TECHNICAL FIELD
[0001] This disclosure relates to a power tool, and in particular to a power tool having
a compact motor assembly.
BACKGROUND
[0002] Power tools such as impact drivers, impact wrenches and the like may be used for
driving threaded fasteners into workpieces. In some situations, these types of power
tools may lack sufficient power to drive a threaded fastener into a workpiece, or
may be too large in length and/or girth to fit into a desired location. In such power
tools, it is desirable to reduce the girth and/or the length of the tool, including
the motor assembly and related components, without sacrificing power and/or performance
of the power.
SUMMARY
[0003] In one general aspect, a power tool includes a housing having a rear end portion
and a front end portion opposite the rear end portion, the front end portion corresponding
to a working end of the power tool; and a motor assembly received in the housing.
The motor assembly may include a rotor configured to rotate about a central axis of
the power tool; a stator assembly operably coupled to the rotor; and magnets received
in magnet pockets defined in the rotor. The power tool may also include a rotor shaft
extending along the central axis, the rotor shaft being coupled to the rotor so as
to be driven by the rotor; a transmission assembly coupled to the rotor shaft and
configured to transmit a torque generated by the motor assembly to an output spindle;
a first bearing configured to support the rotor shaft; and a second bearing configured
to support a component of the transmission assembly. At least a portion of the second
bearing may be radially aligned with at least a portion of the first bearing.
[0004] In some implementations, the first bearing and the second bearing are at least partially
received within a motor envelope defined by a first plane corresponding to a rearmost
portion of the motor assembly and a second plane corresponding to a frontmost portion
of the motor assembly
[0005] In some implementations, the first bearing includes an inner race positioned on the
rotor shaft such that the inner race of the first bearing rotates together with the
rotor shaft at a first speed; and an outer race supported on a first side surface
of a cam carrier plate of the transmission assembly such that the outer race of the
first bearing rotates together with the cam carrier plate at a second speed that is
less than the first speed and the second bearing includes an inner race positioned
on a second side surface of the cam carrier plate, opposite the first side surface
thereof, such that the inner race of the second bearing rotates together with cam
carrier plate at the second speed; and an outer race supported on radial projection
of a ring gear mount coupled to the housing, such that the outer race of the second
bearing is substantially stationary.
[0006] In some implementations, the power tool includes a third bearing coupled to an end
portion of the rotor shaft, opposite an end portion of the rotor shaft to which the
first bearing is coupled, and configured to support the rotor shaft, wherein the third
bearing is received in a bearing pocket defined in a corresponding portion of the
housing; and a fan coupled to the rotor shaft, positioned axially between the third
bearing and the motor assembly.
[0007] In some implementations, the first bearing is mounted on the rotor shaft, positioned
axially between the motor assembly and a cam carrier of the transmission assembly,
such that an axial position of the first bearing is constrained by the cam carrier.
[0008] In another general aspect, a power tool includes a housing having a rear end portion
and a front end portion opposite the rear end portion, the front end portion corresponding
to a working end of the power tool; and a motor assembly received in the housing.
The motor assembly may include a rotor having a rear end portion and a front end portion
configured to rotate about a central axis of the power tool; a stator assembly operably
coupled to the rotor; and magnets received in magnet pockets defined in the rotor.
The power tool may also include a rotor shaft extending along the central axis, the
rotor shaft being coupled to the rotor so as to be driven by the rotor; a transmission
assembly coupled to the rotor and configured to transmit a force generated by the
motor assembly to an output spindle, the transmission assembly including a carrier,
a gear carried by the carrier, and an output member coupled for rotation with the
carrier and extending toward the front end portion; a first bearing configured to
support the front end portion of the rotor shaft, the first bearing in a bearing pocket
defined in a cam shaft at least partially axially forward of the gear carried by the
carrier; and a second bearing configured to support the carrier, the second bearing
being received between the carrier and the housing, such that the second bearing is
such that the second bearing is located between the motor assembly and the first bearing
along the central axis and positioned axially rearward of the first bearing.
[0009] In some implementations, the power tool also includes a pinion having a proximal
end portion coupled to the rotor shaft, and a distal end portion positioned in a bearing
pocket defined in a cam shaft of a cam carrier of the transmission assembly.
[0010] In some implementations, the second bearing is radially aligned with end windings
of the stator assembly, and is at least partially received within a motor envelope
defined by a first plane corresponding to a rearmost portion of the motor assembly
and a second plane corresponding to a frontmost portion of the motor assembly.
[0011] In some implementations, the second bearing is positioned axially rearward of a gear
assembly of the transmission assembly.
[0012] In some implementations, the first bearing includes an inner race positioned on the
distal end portion of the rotor shaft such that the inner race of the first bearing
rotates together with the rotor shaft, via the pinion, at a first speed; and an outer
race supported on an inner wall of the bearing pocket defined in the cam shaft such
that the outer race of the first bearing rotates together with the carrier at a second
speed that is less than the first speed, and the second bearing includes an inner
race positioned on a rear plate portion of the cam carrier such that the inner race
of the second bearing rotates at the second speed together with cam carrier; and an
outer race supported on radial projection of a ring gear mount, such that the outer
race of the second bearing is substantially stationary.
[0013] In some implementations, the power tool includes a third bearing coupled to a proximal
end portion of the rotor shaft and configured to support the rotor shaft, wherein
the third bearing is received in a bearing pocket defined in a corresponding portion
of the housing; and a fan coupled to the rotor shaft, positioned axially between the
third bearing and the motor assembly.
[0014] In another general aspect, a power tool includes a housing having a rear end portion
and a front end portion opposite the rear end portion, the front end portion corresponding
to a working end of the power tool; and a motor assembly received in the housing,
the motor assembly including a rotor configured to rotate about a central axis of
the power tool; a stator assembly operably coupled to the rotor; and magnets received
in magnet pockets defined in the rotor. The power tool may also include a rotor shaft
extending along the central axis, the rotor shaft being coupled to the rotor so as
to be driven by the rotor; a transmission assembly, including a cam carrier, coupled
to the rotor shaft and configured to transmit a force generated by the motor assembly
to an output spindle, and an annular rearward projection coaxial with the central
axis; a fan coupled to a front axial end of the rotor, a first bearing mounted on
the annular rearward projection within a first bearing pocket and configured to support
the fan; and a second bearing mounted on the annular rearward projection within a
second bearing pocket and configured to support the cam carrier, the second bearing
pocket being positioned axially forward of the first bearing pocket.
[0015] In some implementations, a central hub portion of the fan is radially aligned with
stator end windings of the stator assembly.
[0016] In some implementations, at least the first bearing pocket and first bearing mounted
therein are at least partially received within a motor envelope defined by a first
plane corresponding to a rearmost portion of the motor assembly and a second plane
corresponding to a frontmost portion of the motor assembly.
[0017] In some implementations, the second bearing pocket is axially aligned with the first
bearing pocket.
[0018] In some implementations, the first bearing pocket is defined by a central hub portion
of the fan and a rear plate portion of the cam carrier, such that the first bearing
is radially aligned with the central hub portion of the fan and stator end windings
of the stator assembly; and the second bearing pocket is defined by a radial portion
of a ring gear mount coupled to the housing and a rear plate portion of the cam carrier,
such that the second bearing is radially aligned with blades of the fan.
[0019] In some implementations, the first bearing includes an inner race positioned on a
rear plate portion of the cam carrier such that the inner race of the first bearing
rotates at a first speed together with the cam carrier; and an outer race supported
on an inner wall of a central hub portion of the fan such that the outer race of the
first bearing rotates at a second speed together with the fan, and the second bearing
includes an inner race positioned on the rear plate portion of the cam carrier such
that the inner race of the second bearing rotates together with cam carrier at the
first speed; and an outer race supported on radial projection of a ring gear mount
fixed to the housing, such that the outer race of the second bearing is substantially
stationary.
[0020] In some implementations, the power tool includes a pinion that mounts the fan on
the rotor shaft, wherein the pinion mounting of the fan on the rotor shaft supports
an axial position of the first bearing relative to the rotor.
[0021] In some implementations, the power tool includes a third bearing coupled to a rear
end portion of the rotor shaft, such that the rotor is positioned between the third
bearing and the fan, wherein the third bearing is received in a bearing pocket defined
in a corresponding portion of the housing.
[0022] In some implementations, the first bearing pocket and the first bearing received
therein are radially aligned with a central hub portion of the fan and stator end
windings of the stator assembly; and the second bearing pocket and the second bearing
received therein are radially aligned with blades of the fan.
[0023] In some implementations, a central hub portion of the fan has a stepped configuration;
and a ring gear mount positioned axially forward from the central hub portion of the
fan and coupled to the housing has a stepped configuration corresponding to the stepped
configuration of the central hub portion.
[0024] In some implementations, the first bearing pocket is defined by a first stepped portion
of the ring gear mount corresponding to a first stepped portion of the central hub
portion of the fan; and the second bearing pocket is defined by a second stepped portion
of the ring gear mount corresponding to a second stepped portion of the central hub
portion of the fan.
[0025] In some implementations, the first bearing includes an inner race positioned on a
pinion mounted on the rotor shaft such that the inner race of the first bearing rotates
at a first speed together with the rotor shaft via the pinion; and an outer race supported
on the first stepped portion of the ring gear mount such that the outer race of the
first bearing is substantially stationary, and the second bearing includes an inner
race positioned on a rear plate portion of the cam carrier such that the inner race
of the second bearing rotates at a second speed together with the cam carrier; and
an outer race supported on the second stepped portion of the ring gear mount such
that the outer race of the second bearing is substantially stationary.
[0026] In another general aspect, a power tool includes a housing having a rear end portion
and a front end portion opposite the rear end portion, the front end portion corresponding
to a working end of the power tool; and a motor assembly received in the housing,
the motor assembly including a rotor configured to rotate about a central axis of
the power tool; and a stator assembly operably coupled to the rotor; and a plurality
of magnets respectively received in a plurality of magnet pockets axially arranged
in the rotor. The power tool may also include a transmission assembly coupled to the
motor assembly and configured to transmit a force generated by the motor assembly
to an output spindle; a drive pin extending between the transmission assembly and
the rotor so as to transmit a rotational force from the rotor to the transmission
assembly; a fan mounted to a rear portion of the rotor via an interlocking device
configured to rotational fix the fan to the rotor; a first bearing mounted in a first
bearing pocket and configured to support the drive pin; and a second bearing mounted
in a second bearing pocket and configured to support a cam carrier of the transmission
assembly.
[0027] In some implementations, the drive pin includes a gear portion in meshed engagement
with planet gears of the transmission assembly; and a shaft portion configured to
be fitted in a central opening in the rotor such that the drive pin rotates together
with the rotor.
[0028] In some implementations, the first bearing includes an inner race positioned on the
shaft portion of the drive pin such that the inner race of the first bearing rotates
at a first speed together with the drive pin and the rotor; and an outer race supported
on a first side surface of a rear plate portion of the cam carrier such that the outer
race of the first bearing rotates at a second speed together with the cam carrier,
and the second bearing includes an inner race positioned on a second side surface
of the rear plate portion of the cam carrier such that the inner race of the second
bearing rotates at the second speed together with cam carrier; and an outer race supported
on a radial portion of a ring gear mount fixed to the housing such that the outer
race of the second bearing is substantially stationary.
[0029] In some implementations, the second bearing is radially aligned with the first bearing,
and wherein the first bearing and the second bearing are at least partially received
within a motor envelope defined by a first plane corresponding to a rearmost portion
of the motor assembly and a second plane corresponding to a frontmost portion of the
motor assembly.
[0030] In some implementations, the fan includes a plate portion; a central opening formed
in a central portion of the plate portion, wherein the central opening is configured
to receive a protruded rear portion of the rotor for mounting the fan on the rotor;
a plurality of protrusions formed on a portion of a first side of the plate portion,
at positions respectively corresponding to axial end portions of the plurality of
magnet pockets formed in the rotor; and a plurality of blades arranged radially on
the first side of the plate portion.
[0031] In some implementations, the plurality of protrusions are configured to be received
in axial end portions of the plurality of magnet pockets to interlock a position of
the fan relative to the rotor.
[0032] In some implementations, a contour of each protrusion of the plurality of protrusions
corresponds to a contour of a respective axial end portion of a magnet pocket of the
plurality of magnet pockets in which it is received so as to restrict rotation of
the fan relative to the rotor.
[0033] In some implementations, an axial length of the plurality of magnet pockets is greater
than an axial length of the plurality of magnets, and wherein the plurality of protrusions
are received in axial end portions of the plurality of magnet pockets not occupied
by the plurality of magnets.
[0034] In some implementations, a contour of each protrusion of the plurality of protrusions
corresponds to a respective corner portion of the axial end portion of a magnet pocket
of the plurality of magnet pockets in which it is received so as to restrict rotation
of the fan relative to the rotor.
[0035] In some implementations, the power tool includes a recessed area formed in a second
side of the plate portion; and a third bearing mounted on the protruded rear portion
of the rotor and configured to support the rotor, between the recessed area of the
plate portion and a bearing pocket defined in a corresponding portion of the housing,
wherein the third bearing axially constrains a position of the fan.
[0036] In another general aspect, a power tool includes a housing having a rear end portion
and a front end portion opposite the rear end portion, the front end portion corresponding
to a working end of the power tool; a motor assembly received in the housing, the
motor assembly including a stator and a rotor shaft configured to rotate about a central
axis relative to the stator, the rotor shaft having a rear end portion and a front
end portion; a transmission assembly including an input gear rotatably driven by the
rotor shaft and an output shaft that is rotatably driven upon rotation of the input
gear; a rotary impact mechanism including a hammer received over the output shaft,
and an anvil configured to be driven continuously or by rotational impacts by the
hammer; an output spindle coupled to a tool holder and rotatably driven by the anvil;
a first bearing configured to support the rotor shaft; and a second bearing received
in a pocket inside the anvil and configured to support a front end portion of the
output shaft that is received in the pocket, wherein the second bearing is the sole
bearing that rotatably supports the transmission assembly.
[0037] In some implementations, the first bearing is the sole bearing the supports the rotor
shaft.
[0038] In some implementations, the transmission assembly further includes a carrier coupled
to the output shaft and at least one planet gear supported by a pin coupled to the
carrier, the planet gear meshing with the input gear.
[0039] In some implementations, the power tool includes a rolling disc disposed between
the rotor shaft and a stationary component.
[0040] In some implementations, the stationary component is a ring gear of the transmission
assembly that is meshed with the at least one planet gear.
[0041] In some implementations, the stationary component is a portion of the housing.
[0042] In some implementations, the stationary component is a ring gear mount configured
to support a stationary ring gear of the transmission assembly.
[0043] In some implementations, the rolling disc is supported by the pin that supports the
at least one planet gear.
[0044] The details of one or more implementations are set forth in the accompanying drawings
and the description below. Other features will be apparent from the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045]
FIG. 1A is a side view of an example power tool.
FIG. 1B is a schematic partial cross-sectional view of the example power tool shown
in FIG. 1A.
FIG. 1C is a partial cross-sectional view of the example power tool shown in FIG.
1A.
FIG. 1D is an exploded perspective view of an example hammer mechanism of the example
power tool shown in FIGs. 1A-1C.
FIG. 1E is a close-in view of an example motor assembly of the example power tool
shown in FIGs. 1A-1C.
FIG. 2A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 2B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 2A.
FIG. 3A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 3B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 3A.
FIG. 4A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 4B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 4A.
FIG. 5A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 5B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 5A.
FIG. 6A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 6B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 6A.
FIG. 7A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 7B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 7A.
FIG. 7C is a perspective view of an example rotor of the example power tool shown
in FIG. 7A.
FIG. 7D is a perspective view of an example fan coupled to the example rotor shown
in FIG. 7C.
FIG. 7E is a disassembled cross-sectional view, taken along line E-E of FIG. 7D.
FIG. 7F is an assembled cross-sectional view, taken along line E-E of FIG. 7D.
FIG. 7G is an exploded perspective view of an example drive assembly.
FIG. 7H is an assembled perspective view of the example drive assembly shown in FIG.
7F.
FIG. 7I is a cross-sectional view taken along line F-F of FIG. 7H.
FIG. 7J is a partially assembled perspective view of an example fan, and example rotor,
and the example drive assembly shown in FIGs. 7G and 7H.
FIG. 7K is an assembled view of the example fan, the example rotor, and the example
drive assembly.
FIG. 7L is a cross-sectional view taken along line G-G of FIG. 7K.
FIG. 8A is a partial cross-sectional view of an example power tool, in accordance
with implementations described herein.
FIG. 8B is a close-in view of an example motor assembly of the example power tool
shown in FIG. 8A.
FIG. 8C is a perspective view of an example fan of the example power tool shown in
FIG. 8A.
FIG. 9 is a partial cross-sectional view of an example power tool, in accordance with
implementations described herein.
FIG. 10A is a perspective view, and FIG. 10B is a side view, illustrating internal
components of the example power tool, in accordance with implementations described
herein.
FIGs. 10C and 10D are partial cross-sectional views, and FIGs. 10E-10G are perspective
views, of components of an example impact mechanism 1400 of the example power tool
shown in FIGs. 10A and 10B.
FIGs. 10H-10J are perspective views of an example cam carrier of the example power
tool shown in FIGs. 10A and 10B.
DETAILED DESCRIPTION
[0046] Example implementations will now be described more fully with reference to the accompanying
drawings. It is to be understood that both the foregoing general description and the
following detailed description are provided for purposes of discussion and illustration
only, and are intended to provide an explanation of various implementations of the
present teachings.
[0047] FIG. 1A is a side view of an example power tool 100, in the form of an example impact
tool. FIG. 1B is a partial cross-sectional schematic view of the example power tool
100 shown in FIG. 1A. FIG. 1C is a partial cross-sectional view of the example power
tool 100 shown in FIG. 1A. FIG. 1D is an exploded view of an example transmission
assembly and an example impact mechanism 140 of the example power tool 100 shown in
FIG. 1A.
[0048] In the example shown in FIGs. 1A and 1B, the example power tool 100 includes a housing
190 having a motor housing portion 193 and a transmission housing portion 191 coupled
to the motor housing portion 193. The motor housing portion 193 includes two clamshells
that come together to house a motor assembly 110 that rotatably drives a rotor shaft
102. The transmission housing portion 191 houses a transmission assembly 120 and an
impact mechanism 140 that together selectively impart a rotary motion and/or a rotary
impact motion to an output spindle 160. Example implementations described herein include
an impact mechanism 140, simply for purposes of discussion and illustration. The principles
described herein may be applied to rotary power driven tools that do not include an
impact mechanism. For example, in some implementations, the power tool may be a drill
that does not include an impact mechanism, such that the power tool imparts only rotary
motion to the output spindle, or may be a hammer drill and may include an axially
oriented impact mechanism so that rotary motion and axial impacts are transmitted
to the output spindle. A tool holder 170 is coupled to the output spindle 160. The
tool holder 170 is configured to retain an accessory tool (e.g., a drill bit, a screw
driving bit, a socket wrench, and other such accessory tools, not shown). Further
details regarding example tool holders are set forth in
U.S. patent application Ser. 12/394,426. In alternative implementations, the tool holder may comprise a keyed or keyless
chuck or a collet.
[0049] The example power tool 100 includes a handle 192 that extends transverse to the housing
190. The handle 192 may accommodate a trigger 196, a control and/or power module (not
shown) that includes control electronics and switching components for driving the
motor assembly 110, and a battery receptacle 194 that receives a removeable power
tool battery pack for supplying electric power to the motor assembly 110. The handle
192 has a proximal portion coupled to the housing 190 and a distal portion coupled
to the battery receptacle 194. The motor assembly 110 may be powered by an electrical
power source, such as a DC power source or battery (not shown), that is coupled to
the battery receptacle 194, or by an AC power source. In some examples, the trigger
196 is coupled at a portion of the handle 192 adjacent the housing 190. The trigger
196 connects the electrical power source to the motor assembly 110 via the control
and/or power module, which controls power delivery to the motor assembly 110. The
rotor shaft 102 rotates in response to power supplied to the motor assembly 110. Rotation
of the rotor shaft 102 generates a rotational force that is transmitted to an accessory
tool coupled to the example power tool by the tool holder 170, via the transmission
assembly 120 and the output spindle 160, to perform an operation on a workpiece.
[0050] As shown in FIGs. 1C and 1D, in some examples, the transmission assembly 120 may
be a planetary transmission including, among other features, a pinion or sun gear
122 that is coupled to an end of the rotor shaft 102 of the motor assembly 110, and
that extends along a tool axis X into a cavity 121 formed in the cam shaft 129 of
the carrier 126 and defining a bearing pocket for the front motor bearing within the
cam shaft 129. One or more planet gears 124 are positioned surrounding the sun gear
122. Teeth on an outer circumferential surface of the one or more planet gears 124
mesh with the teeth on an outer circumferential surface of the sun gear 122. An outer
ring gear 123 is rotationally fixed to the housing 190 and centered on the tool axis
X. Teeth formed on an inner circumferential surface of the outer ring gear 123 mesh
with the teeth on the planet gears 124.
[0051] A carrier 126 (which may be part of a cam carrier) includes a pair of carrier plates,
i.e., a first, or rear carrier plate 126A and a second, or front carrier plate 126B,
that support the one or more planet gears 124. Each of the planet gears 124 is mounted
on a pin 125 extending between the rear carrier plate 126A and the front carrier plate
126B, so that the planet gears 124 can rotate about the pins 125. In other implementations,
the carrier 126 may only have a single carrier plate with the pins coupled to the
single carrier plate. The carrier 126 includes a rearward projection 127 having an
annular body that extends axially rearward from the rear carrier plate 126A along
the tool axis X. The carrier may be integrally or non-integrally coupled to a cam
shaft 129 that extends axially forward from the front carrier plate 126B along the
tool axis X to form the cam carrier. In other implementations the carrier 126 may
be integrally or non-integrally coupled directly to the output spindle or may be coupled
to other transmission components such as a sun gear for another planetary transmission
stage, a clutch, or a spindle lock assembly.
[0052] In response to the application of power to the motor assembly 110, the rotor shaft
102 and the sun gear 122 rotate about the axis X. Rotation of the sun gear 122 causes
the planet gears 124 to orbit the sun gear 122 about the axis X, which in turn causes
the carrier 126 to rotate about the axis X at a reduced speed relative to the rotational
speed of the rotor shaft 102. In the example shown in FIGs. 1C and 1D, the transmission
assembly 120 includes a single planetary stage, simply for purposes of discussion
and illustration. The principles to be described herein can be applied to an arrangement
including multiple planetary stages that may provide for multiple speed reductions,
and that each stage can be selectively actuated to provide for multiple different
output speeds of the carrier 126. In some examples, the transmission assembly 120
may include a different type of gear system such as, for example, a parallel axis
transmission, a spur gear transmission, and the like.
[0053] In the example arrangement shown in FIGs. 1C and 1D, the impact mechanism 140 includes
the cam shaft 129, with a generally cylindrical hammer 142 received over the cam shaft
129. In some examples, the hammer 142 may selectively engage the output spindle 160,
based on a position of the hammer 142 on the cam shaft 129. That is, the hammer 142
may be movably coupled on the cam shaft 129. The hammer 142 may include lugs 145 configured
to engage corresponding projections 146 extending radially from an anvil 144 fixedly
coupled on the output spindle 160. A pair of rear-facing V-shaped cam grooves 147
may be formed on an outer surface of the cam shaft 129. Open end portions of the V-shaped
cam grooves 47 may be oriented toward the transmission assembly 120. The hammer 142
may be movably coupled to the cam shaft 129, with relative movement therebetween guided
by, for example, balls 149 received in the V-shaped cam grooves 147. In this example,
a compression spring 141 is received in a cylindrical recess in the hammer 142, abutting
a forward face of the front carrier plate 126B. The spring 141 biases the hammer 142
toward the anvil 144 so that the
lugs 145 engage the corresponding projections 146 formed on the anvil 144. An example
of an impact mechanism is further described in
U.S. Pat. App. Pub. No. 2019/0344411, filed July 26, 2019.
[0054] At low torque levels, the impact mechanism 140 transmits torque from the transmission
assembly 120 to the output spindle 160 in a rotary mode of operation of the power
tool 100. In the rotary mode, the compression spring 141 maintains the hammer 142
in a forward position so that the lugs 145 continuously engage the projections 146.
This causes the cam shaft 129, the hammer 142, the anvil 144, and the output spindle
160 to rotate together as a unit about the axis X. As torque increases, the impact
mechanism 140 may transition to transmitting torque to the output spindle 160 in an
impact mode. During operation of the example power tool 100 in the impact mode, the
hammer 142 moves axially rearward against the force of the spring 141, decoupling
the lugs 145 from the projections 146. The anvil 44 continues to spin freely about
the axis X, though driven by the motor assembly 110 and the transmission assembly
120, so that the anvil 144 coasts to a slower speed than the hammer 142. The hammer
142 continues to be driven at a higher speed by the motor assembly 110 and transmission
assembly 120, while the hammer 142 moves axially rearward relative to the anvil 144
by the movement of the balls 149 in the V-shaped cam grooves 147. When the balls 149
reach a rearmost position in the V-shaped cam grooves 147, the spring 141 drives the
hammer 142 axially forward with a rotational speed that exceeds the rotational speed
of the anvil 144. This causes the lugs 145 to rotationally strike the projections
146, imparting a rotational impact to the output spindle 160.
[0055] In some examples, the motor assembly 110 is a brushless direct-current (BLDC) motor
that includes an inner rotor 104 having surface-mount rotor magnets 106 on a rotor
core 108, and a stator assembly 111 located around the rotor 104. The stator assembly
111 includes a stator core 112 having a series of teeth 114 projecting radially inward
from the stator core 112, and a series of conductive windings 113 wound around the
stator teeth 114 to define three phases connected in a wye or a delta configuration.
As the phases of the stator assembly 111 are sequentially energized, they interact
with the rotor magnets 106 to cause rotation of the rotor 104 relative to the stator
assembly 111.
[0056] In some examples, the rotor core 108 is mounted on the rotor shaft 102 and includes
an annular recess 116 around the rotor shaft 102, on one side of the rotor core 108.
In the example shown in FIGs. 1C and 1D, the rotor 104 is provided with what is referred
to in this disclosure as an open-core construction, where the rotor magnet 106 is
mounted around the core 112 and the annular recess 116 is provided within the core
112 for positioning of one or more of the rotor bearings. The core 112 may be made
of a solid core piece of metal or lamination stack that includes a series of parallel
laminations. The annular recess 116 may be carved or stamped out of the core 112,
or it may be formed using ring-shaped laminations.
[0057] In the example shown in FIGs. 1C-1E, the rotor magnet 106 has a ring configuration
that is surface-mounted on the outer surface of the rotor core 108 and magnetized
in a series of poles, e.g., four poles having a S-N-S-N orientation. In some examples,
the rotor magnet 106 may be provided as a series of discrete magnet segments that
may be pre-magnetized prior to assembly, with the outer surface of the rotor core
108 shaped for retention of the magnet segments. In some examples, the rotor magnets
106 may be fully or partially embedded within the rotor core 108.
[0058] In some examples, a fan 118 is mounted on the rotor shaft 102 behind the motor assembly
110. A tool cap 198 may be mounted to the end of the housing 190 to contain the end
of the motor assembly 110. The tool cap 198 may be provided integrally with the housing
190 or as a separate piece. In some examples, the fan 118 is positioned between the
motor assembly 110 and the tool cap 198. The fan 118 generates airflow through the
motor assembly 110 and the transmission assembly 120 to cool the components.
[0059] In some examples, a ring gear mount 130 supports a front motor bearing 156 and a
rear motor bearing 158 supporting the rotor shaft 102. In the example shown in FIG.
1C, at least the rear motor bearing 158 is located within the stator assembly 111
and within the annular recess 116 defined by the rotor core 108 along the axial direction
of the motor assembly 110, such that the rear motor bearing 158 intersects a portion
of the rotor core 108 along a radial plane. The ring gear mount 130 includes a cylindrical
portion 132 that receives the outer races of the motor bearings 156 and 158 and a
radial portion 134 that extends radially from the cylindrical portion 132 and includes
radial ends supported by the tool housing 190. The stator assembly 111 is also supported
by the tool housing 190, thus being axially and radially secure with respect to the
ring gear mount 130. In this manner, the ring gear mount 130 axially and radially
supports the rotor 104 within the stator assembly 111. In some examples, the ring
gear mount 130 and the stator assembly 111 may be independently supported by the tool
housing 190. In some examples, the ring gear mount 130 may be formed integrally as
a part of two clamshells that form the tool housing 190. In some examples, the ring
gear mount 130 may be piloted to and retained by the stator assembly 111 directly
and independently of the tool housing 190.
[0060] As shown in FIG. 1C, in some examples, the ring gear mount 130 includes a front lip
131 that supports a component of the transmission assembly1 20, such as, for example,
the ring gear 123, to inhibit axial and rotational movement of the ring gear 123 relative
to the housing 190. In some examples, the ring gear mount 130 supports a cam carrier
bearing 154 that supports the carrier 126 relative to the ring gear mount 130, and
therefore relative to the motor assembly 110 and the tool housing 190. The cam carrier
bearing 154 is nested within the ring gear mount 130 adjacent the motor assembly 110.
Specifically, in this example arrangement, the ring gear mount 130 is positioned between
the motor assembly 110 and the transmission assembly 120, and provides support for
the motor bearings 156 and 158 on one side, and provides support for the cam carrier
bearing 154 on the other side. In some examples, the ring gear mount 130 includes
a recessed portion 136 having a larger diameter than the radial portion 134, such
that the recessed portion 136 is sized to receive the cam carrier bearing 154 therein.
The cam carrier bearing 154 is thus located axially forward of the motor assembly
110.
[0061] At least a portion of the ring gear mount 130 is received within the stator assembly
111 and within the rotor core 108. In this example, the rear cylindrical projection
of the ring gear mount 130 that supports the motor bearings 156 and 158 is at least
partially received within the stator assembly 111 and within the rotor core 108. In
this example, the nested arrangement of motor bearings 156 and 158 and the ring gear
mount 130 provide a compact motor assembly 110 compared to conventionally available
brushless motors. Disposition of the motor bearings 156 and 158 and at least a portion
of the ring gear mount 130 within the stator assembly 111 and within the rotor core
108 reduces the length of the motor assembly 110, reduces the overall length of the
power tool 100, and improves power density.
[0062] In some examples, the motor assembly 110 defines a motor envelope 180 bounded by
a rear plane 182 at a rearmost portion of the motor assembly 110 (i.e., at the rearmost
point of the stator assembly 111), a front plane 184 at a frontmost portion of the
motor assembly 110 (i.e., at the frontmost point of the stator assembly 111), and
a generally cylindrical boundary 186 extending from the rear plane 182 to the front
plane 184 and surrounding a radially outermost portion of the motor assembly 110 (e.g.,
a radially outermost portion of the stator assembly 111) not including terminal block
151. In the example shown in FIG. 1E, the rear plane 182 is at a rearmost portion
of the stator assembly 111 (including the windings 113), the front plane 184 is at
a frontmost point of the stator assembly 11 (including the windings 113), and the
generally cylindrical boundary 186 surrounds a radially outermost portion of the stator
assembly 111. In some examples, the rear plane may be defined at a rearmost point
of the rotor 104, if the rotor 104 extends further rearward than the stator assembly
111, the front plane may be defined at a frontmost point of the rotor 104, if the
rotor 104 extends further frontward than the stator assembly 111, and the generally
cylindrical boundary may defined be at an outermost point of the rotor 104, if the
rotor 104 extends further radially outward than the stator assembly 11 (for example,
as would be the case in an outer rotor motor). The motor envelope 180 may have a length
L1 from the rear plane 182 to the front plane 184. The motor envelope 180 may have
a diameter D1 corresponding to the cylindrical boundary 186. In some examples, at
least a portion of at least one of the motor bearings 156 and 158 and at least a portion
of the ring gear mount 130 are received within the motor envelope 180.
[0063] FIGs. 2A and 2B present an example power tool 200, in accordance with implementations
described herein. In particular, FIG. 2A is a partial cross-sectional view of the
example power tool 200, and FIG. 2B is a zoomed-in partial cross-sectional view of
the example power tool 200.
[0064] The example power tool 200 shown in FIGs. 2A and 2B includes a motor assembly 210
and a ring gear mount 230 that are physically configured to provide for a reduced
overall length of the power tool 200 (for example, compared to an overall length of
the power tool 100 described above with respect to FIGs. 1A-1E). Many features of
the example power tool 200 are similar to features of the power tool 100 described
above with respect to FIGs. 1A-1E, such as, for the example the transmission assembly
120, the impact mechanism 140, the output spindle 160, the tool holder 170, the housing
190 including the handle 192, the trigger 196, the receptacle 194, and the like. Thus,
duplicative detailed description thereof will not be repeated except as necessary.
[0065] In the example shown in FIGs. 2A and 2B, the ring gear mount 230 is configured to
position the cam carrier bearing along substantially the same radial plane as at least
an end of the stator windings, so that the cam carrier bearing is positioned at least
partially within an envelope defined by the ends of the motor assembly 210. In some
examples, the motor assembly 210 includes a rotor shaft 202, an inner rotor 204 mounted
on the rotor shaft 202 with a ring shaped surface-mount rotor magnet 206 on a rotor
core 208, and a stator assembly 211 positioned around the rotor 204. The stator assembly
211 includes a stator core 212, a series of stator teeth 214 radially projecting inwardly
from the core 212, and a series of conductive windings 113 wound around the stator
teeth 214 to define three phases connected in a wye or a delta configuration.
[0066] In this arrangement, the motor assembly 210 defines the tool axis X extending along
a longitudinal centerline of the rotor shaft 202, from a rear end portion of the power
tool 300 (i.e., an end portion of the power tool 200 corresponding to the tool cap
198) to a front end portion of the power tool 200 (i.e., an end portion of the power
tool 200 corresponding to the tool holder 170). In this disclosure, the terms "rear"
and "front" are used to describe relative positions of various components along the
tool axis X. Thus, as an example, in the arrangement shown in FIGs. 2A and 2B, the
motor assembly 210 is disposed rearward of the transmission assembly 120.
[0067] In the example shown in FIGs. 2A and 2B, the rotor core 208 is mounted on the rotor
shaft 202. An annular recess 216 is formed around the rotor shaft 202, on one side
of the rotor core 208, for positioning of one or more of a first, or front motor bearing
256 and/or a second, or rear motor bearing 258. The core 212 may be made of a solid
core piece of metal or lamination stack that includes a series of parallel laminations.
In some examples, the annular recess 216 is carved or stamped out of the core 212.
In some examples, the annular recess 216 is formed using ring-shaped laminations.
The rotor magnet 206 may be ring-shaped or segmented, and it may be surface-mounted
or embedded within the rotor core 208.
[0068] In this example arrangement, the ring gear mount 230 includes a first bearing pocket
232 formed as a cylindrical or rim-shaped projection extending from a radial portion
234 of the ring gear mount 230, for supporting at least the front motor bearing 256.
The first bearing pocket 232 of the ring gear mount 230 at least partially projects
into and is received within the annular recess 216 of the rotor 204. This allows the
front motor bearing 256 to be received at least partially within the stator assembly
211 and within an envelope defined by the radial surfaces of the rotor core 208.
[0069] In the example shown in FIGs. 2A and 2B, the ring gear
mount 230 includes a second bearing pocket 236 for supporting a cam carrier bearing
254. The second bearing pocket 236 may be formed as a recessed portion of the radial
portion 234 of the ring gear mount 230 facing away from the first bearing pocket 232.
In some examples, the second bearing pocket 236 is formed as an intermediate annular
portion formed between the radial portion 234 and a radial wall 235, where the radial
portion 234 is located along a radial plane that intersects a portion of the stator
assembly 211, and the radial wall 235 is located adjacent a front end portion of the
stator assembly 211. As such, the radial portion 234 extends between a front end of
the first bearing pocket 232 and a rear end of the second bearing pocket 236. In some
examples, the radial wall 235 extends radially outward from the front end of the second
bearing pocket 236 and is supported by either the tool housing 190 or the stator assembly
211. In some examples, the ring gear mount 230 includes an outer rim portion or a
lip 231 projecting axially forward from an outer circumference of the radial wall
235 for coupling with a corresponding portion of the transmission housing portion
191 and/or the tool housing 190 and for receiving and supporting a component of the
transmission assembly 120, such as the ring gear 123 of the transmission assembly
120.
[0070] In some examples, an inner diameter of the second bearing pocket 236 is greater than
an inner diameter of the first bearing pocket 232. In some examples, the inner diameter
of the second bearing pocket 236 is substantially the same as the outside surface
of the rotor core 208. In some examples, the outer surface of the second bearing pocket
236 is received within the opening of the stator assembly 211, i.e., within the inner
diameter formed by front end portions of the stator windings 213 adjacent the rotor
204. In some examples, the outer annular surface of the second bearing pocket 236
may be in physical contact with the stator windings 213 or a front end insulator 219
of the stator assembly 211. In some examples, a relatively small air gap 217 radially
separates the outer annular surface of the second bearing pocket 236 from the stator
windings 213 and the front end insulator 219 of the stator assembly 211.
[0071] In some examples, the cam carrier bearing 254 is received within the second bearing
pocket 236 so that it is at least partially nested within the stator assembly 211
along a radial plane that intersects the front end portions of the stator windings
213.
[0072] In some examples, the motor assembly 210 defines a motor envelope 280 similar to
the motor envelope 180 of the motor assembly 110 described above. The motor envelope
280 is bounded by a rear plane 282 at a rearmost portion of the motor assembly 210
(i.e., at the rearmost portion of the stator assembly 211), a front plane 284 at a
frontmost portion of the motor assembly 210, and a generally cylindrical boundary
286 extending from the rear plane 282 to the front plane 284 and surrounding a radially
outermost portion of the motor assembly 210 (e.g., a radially outermost portion of
the stator assembly 211). In the example arrangement shown in FIGs. 2A and 2B, the
rear plane 282 is at a rearmost portion of the stator assembly 211 (including the
stator windings 213), the front plane 284 is at a frontmost point of the stator assembly
211 (including the stator windings 213), and the generally cylindrical boundary 286
surrounds a radially outermost portion of the stator assembly 211 (not including the
terminal block 251). In some examples, the rear plane may be at a rearmost portion
of the rotor 204 (if the rotor 204 extends further rearward than the stator assembly
211), the front plane may be at a frontmost portion of the rotor 204 (if the rotor
204 extends further frontward than the stator assembly 211), and the generally cylindrical
boundary may be at an outermost portion of the rotor 204 (if the rotor 204 extends
further radially outward than the stator assembly 211, such as, for example, in an
outer rotor motor). As shown in FIG. 2B, the motor envelope 280 may have a length
L2 from the rear plane 282 to the front plane 284 and a diameter D2 of the cylindrical
boundary 286. In some examples, at least a portion of the front motor bearing 256
and at least a portion of the ring gear mount 230 are received within the motor envelope
280.
[0073] In the example arrangements shown in FIGs. 1C-1E, 2A and 2B, depending on a length
of the rotor core 208, the configuration, for example, the shape and/or the contour,
of the ring gear mount 230 together with the open rotor core 208, allows one or both
of the motor bearings 256 and 258 to be at least partially received within the annular
recess 216 formed by the core 212. In particular, in the arrangement shown in FIGs.
2A and 2B, the front motor bearing 256 is supported within the annular recess 216
of the core 212, with the front motor bearing 256 positioned within the motor envelope
280, and the cam carrier bearing 254 at least partially positioned within the motor
envelope 280. In the example arrangement shown in FIGs. 2A and 2B, the rear motor
bearing 258 is supported by the tool cap 198 coupled to the rear end portion of the
tool housing 190. In some examples, the tool cap 198 includes a radial body that includes
a central bearing pocket for supporting the rear motor bearing 258.
[0074] In some examples, a fan 218 is mounted on the rotor shaft 202 to rotate with the
rotation of the motor assembly 210. The fan 218 includes a radial main body and a
plurality of blades facing the stator assembly 211. In some examples, an inner portion
of the fan 218 is recessed to allow the rear motor bearing 258 to be at least partially
nested in the axial direction within the fan 218, and to be radially aligned with
the main body of the fan 218. The bearing pocket defined by the tool cap 198 may be
axially received within the recessed portion of the fan 218, around the rear motor
bearing 258, so that positioning of the rear motor bearing 258 within the rear tool
cap 198 does not pose a significant increase in the overall length of the motor assembly
210.
[0075] FIGs. 3A and 3B present an example power tool 300, in accordance with implementations
described herein. In particular, FIG. 3A is a partial cross-sectional view illustrating
internal components of the example power tool 300, and FIG. 3B is a zoomed-in partial
cross-sectional view of internal components of the example power tool 300.
[0076] The example power tool 300 shown in FIGs. 3A and 3B includes a motor assembly 310
and a ring gear mount 330 that are physically configured to provide for a reduced
overall length and/or girth of the power tool 300 (for example, compared to an overall
length and/or girth of the power tool 100 described above with respect to FIGs. 1A-1E).
Many features of the example power tool 300 are similar to features of the example
power tool 100 described above with respect to FIGs. 1A-1E and/or the example power
tool 200 described above with respect to FIGs. 2A and 2B, such as, for the example
the transmission assembly 120, the impact mechanism 140, the output spindle 160, the
tool holder 170, the housing 190 including the handle 192, the trigger 196, the receptacle
194, and the like. Thus, duplicative detailed description thereof will not be repeated
except as necessary.
[0077] In the example shown in FIGs. 3A and 3B, the motor assembly 310 includes a solid
core rotor configuration, rather than the open core rotor configuration of the example
motor assembly 210 described above with respect to FIGs. 2A and 2B and/or the example
motor assembly 110 described above with respect to FIGs. 1C-1E. In the example shown
in FIGs. 3A and 3B, the motor assembly 310 includes an embedded magnet configuration,
rather than the surface mounted ring configuration of the magnet of the example motor
assembly 210 shown in FIGs. 2A and 2B.
[0078] As described above, the open core rotor configuration, together with the surface
mounted ring configuration of the magnet, of the example motor assembly 210, allows
for the front motor bearing 256 to be received in the annular recess 216 formed within
the rotor core 208, piloted by the ring gear mount 230, such that at least one of
the front motor bearing 256 and/or the rear motor bearing 258 can be received within
the envelope 280 defined by the motor assembly 210. In contrast, in the example motor
assembly 310 shown in FIGs. 3A and 3B, the solid core rotor configuration including
the embedded magnets does not form an annular recess in which the front motor bearing
and/or the rear motor bearing and/or the cam carrier bearing can be accommodated.
Rather, the example motor assembly 310 shown in FIGs. 3A and 3B includes a ring gear
mount 330 configured such that a front motor bearing can be radially aligned with
a cam carrier bearing, and for both the front motor bearing and the cam carrier bearing
to be substantially radially aligned with corresponding end portion(s) of stator windings
of the motor assembly 310. In the example arrangement shown in FIGs. 3A and 3B, the
cam carrier (rather than the ring gear mount 230 as in the example arrangement shown
in FIGs. 2A and 2B) indexes, or sets a location for, or supports a position of the
front motor bearing. The configuration of the ring gear mount 330 allows for a reduced
overall length of the example power tool 300 (for example compared to the overall
length of the example power tool 100 described above with respect to FIGs. 1A-1E)
and/or an overall length that is less than or equal to the overall length of the example
power tool 200 shown in FIGs. 2A and 2B, but with the motor assembly 310 including
the solid core rotor configuration and embedded magnet configuration.
[0079] In some examples, the motor assembly 310 includes a rotor 304 including magnets 306
mounted in magnet pockets 307 formed in a rotor core 308. The example motor assembly
310 shown in FIGs. 3A and 3B has an internal permanent magnet configuration in which
the rotor magnets 306 are mounted in the magnet pockets 307 defined in the rotor core
308, such that the rotor magnets 306 are embedded in the rotor core 308. The rotor
core 308 is mounted on the rotor shaft 302. A stator assembly 311 is positioned around
the rotor 304. The stator assembly 311 includes a stator core 312 having a series
of teeth projecting radially inward from the stator core 312, and a series of conductive
windings 313 wound around the stator teeth. As the phases of the stator assembly 311
are sequentially energized, they interact with the rotor magnets 306 to cause rotation
of the rotor 304 relative to the stator assembly 311.
[0080] In the example shown in FIGs. 3A and 3B, the ring gear mount 330 includes a cylindrical
or rim-shaped portion 333, and a radial portion 334 extending radially outward from
the rim-shaped portion 333 of the ring gear mount 330. The ring gear mount 330 includes
an outer rim portion or a lip 331 projecting axially forward from the radial portion
334, for coupling with a corresponding portion of the transmission housing portion
191 and/or the tool housing 190, and for receiving and supporting a component of the
transmission assembly 120, such as the ring gear 123. The rim-shaped portion 333 (for
example, together with corresponding portions of the rear carrier plate 126A and the
rearward projection 127 of the carrier 126) defines a bearing pocket 332 in which
a cam carrier bearing 354 is received. In this example arrangement, the cam carrier
bearing 354 is supported by the ring gear mount 330, and in particular, the outer
race of the cam carrier bearing 354 is supported by the rim-shaped portion 333 of
the ring gear mount 330.
[0081] In the example arrangement shown in FIGs. 3A and 3B, a front motor bearing 356 is
mounted on the rotor shaft 302, and is piloted, located, set in position, and/or supported,
by the rearward projection 127 of the rear carrier plate 126A of the carrier 126.
In this example arrangement, the rearward projection 127 is fitted between the front
motor bearing 356 and the cam carrier bearing 354. Thus, in this example arrangement,
an outer race of the cam carrier bearing 354 is supported by the (stationary) ring
gear mount 330, with an inner race being supported by and rotating with the rearward
projection 127 of the carrier 126. The outer race of the front motor bearing 356 is
supported by the rearward projection 127, that rotates with the carrier 126. That
is, in this example, the outer race of the front motor bearing 356 rotates together
with the carrier 126, at a somewhat lower speed than the inner race of the front motor
bearing 356 that rotates together with the rotor shaft 302.
[0082] In the example arrangement shown in FIGs. 3A and 3B, a rear motor bearing 358 is
supported by the tool cap 198 coupled to the rear end portion of the tool housing
190. In some examples, a fan 318 is mounted on the rotor shaft 302 to rotate with
the rotation of the motor assembly 310. In some examples, the fan 318 includes a radial
main body and a plurality of blades facing the stator assembly 311. In some examples,
a central hub portion of the fan 318 is recessed to allow the rear motor bearing 358
to be at least partially nested in the axial direction within the fan 318, and to
be radially aligned with the main body of the fan 318. The bearing pocket defined
by the tool cap 198 may be axially received within the recessed portion of the fan
318, around the rear motor bearing 358, so that positioning of the rear motor bearing
358 within the rear tool cap 198 does not pose a significant increase in the overall
length of the motor assembly 310.
[0083] In the example arrangement shown in FIGs. 3A and 3B, the front motor bearing 356
has been moved axially rearward, such that the front motor bearing 356 is substantially
radially aligned with the cam carrier bearing 354, and substantially radially aligned
with the conductive windings 313, and the front motor bearing 356 and the cam carrier
bearing 354 are at least partially received within a motor envelope 380 of the motor
assembly 310. As described above, the motor envelope 380 may be bounded by a rear
plane 382 at a rearmost portion of the motor assembly 310 (i.e., at the rearmost portion
of the stator assembly 311), a front plane 384 at a frontmost portion of the motor
assembly 310, and a generally cylindrical boundary 386 extending from the rear plane
382 to the front plane 384 and surrounding a radially outermost portion of the motor
assembly 310 (e.g., a radially outermost portion of the stator assembly 311). The
motor envelope 380 may have a length L3 from the rear plane 382 to the front plane
384 and a diameter D3 of the cylindrical boundary 386. In some examples, at least
a portion of the front motor bearing 356 and at least a portion of the cam carrier
bearing 354 are received within the motor envelope 380. In some examples, the length
L3 associated with the motor assembly 310 shown in FIGs. 3A and 3B may be less than
or equal to the length L2 associated with the motor assembly 210 shown in FIGs. 2A
and 2B. In some examples, the diameter D3 associated with the motor assembly 310 shown
in FIGs. 3A and 3B may be less than or equal to the diameter D2 associated with the
motor assembly 210 shown in FIGs. 2A and 2B.
[0084] In some implementations, the length L3 of the example motor assembly 310 may be between
approximately 16.0 mm and 19.4 mm. In some examples, the length L3 may be smaller
than or equal to approximately 17.7 mm. In some implementations, the diameter D3 of
the example power tool 300 may be between approximately 46.0 mm and 56.0 mm. In some
examples, the diameter D3 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 300 may be
between approximately 89.0 mm and 109.0 mm. In some examples, the overall axial length
of the example power tool 300 may be smaller than or equal to approximately 99.5 mm.
In some implementations, an overall girth of the example power tool 300 may be between
approximately 60.0 mm and 72.0 mm. In some examples, the overall girth of the example
power tool 300 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 310 (i.e., frontmost
part of the conductive windings 313) to a rear end portion of the carrier 126 (i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 3.0 mm and
5.5 mm. In some examples, the axial length from the front end portion of the motor
assembly 310 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 5.0 mm, preferably smaller than or equal to approximately 4.6 mm, more
preferably smaller than or equal to approximately 4.2 mm. Accordingly, In some implementations,
an axial length from a rear end portion of the motor assembly 310 to a front end portion
of the tool holder 170 is between approximately 85.0 mm and 104.0 mm. In some examples,
the axial length from the rear end portion of the motor assembly 310 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 94.37
mm. In some implementations, an inner diameter of the ring gear mount 330 is between
approximately 21.6 mm and 26.4 mm. In some examples, the inner diameter of the ring
gear mount 330 is smaller than or equal to approximately 24.0 mm. In some implementations,
an outer diameter of the ring gear mount 330 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 330 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 310
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 310 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 310 is greater than or equal
to approximately 440 W when using an 20V max battery pack, with current drawn by the
motor assembly 310 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 300, a ratio of the maximum power output of the motor assembly 310 to the
axial length from the front end portion of the motor assembly 310 to the rear end
portion of the carrier 126 is greater than or equal to approximately 86 W/mm, preferably
greater than or equal to approximately 90 W/mm, more preferably greater than or equal
to approximately 94 W/mm. In some implementations, an output torque of the example
power tool 300 is between approximately 1642.0 in-lbs and 2007 in-lbs when using a
20V max battery pack. In some examples, the output torque of the example power tool
300 is greater than or equal to approximately 1825 in-lbs when using a 20V max battery
pack. In some examples, the output torque of the example power tool 300 is greater
than or equal to 2400 in-lbs.
[0085] FIGs. 4A and 4B present an example power tool 400, in accordance with implementations
described herein. In particular, FIG. 4A is a partial cross-sectional view of internal
components of the example power tool 400, and FIG. 4B is a zoomed-in partial cross-sectional
view of the internal components the example power tool 400.
[0086] The example power tool 400 shown in FIGs. 4A and 4B includes a motor assembly and
a ring gear mount that are physically configured to provide for a reduced overall
length and/or girth of the power tool 400, together with the fitting of a front motor
bearing in a cavity formed within a cam shaft and defining a bearing pocket for the
front motor bearing (for example, compared to an overall length and/or girth of the
power tool 100 described above with respect to FIGs. 1A-1E). Many features of the
example power tool 400 are similar to features of the power tool 100 described above
with respect to FIGs. 1A-1E and/or the example power tool 200 described above with
respect to FIGs. 2A and 2B, and/or the example power tool 300 described above with
respect to FIGs. 3A and 3B, such as, for the example the transmission assembly 120,
the impact mechanism 140, the output spindle 160, the tool holder 170, the housing
190 including the handle 192, the trigger 196, the receptacle 194, and the like. Thus,
duplicative detailed description thereof will not be repeated except as necessary.
[0087] In the example shown in FIGs. 4A and 4B, the motor assembly 410 includes a solid
core rotor configuration, rather than the open core rotor configuration described
above with respect to FIGs. 1C-2B. In the example shown in FIGs. 4A and 4B, the motor
assembly 410 includes an embedded magnet configuration, rather than the surface mounted
ring configuration of the magnet of the example motor assembly 210 shown in FIGs.
2A and 2B. As described above, due to the solid core rotor configuration including
the embedded magnets of the example motor assembly 410 shown in FIGs. 4A and 4B, the
rotor does not form an annular recess in which the front motor bearing and/or the
rear motor bearing and/or the cam carrier bearing can be accommodated. Rather, in
the example motor assembly 410 shown in FIGs. 4A and 4B, the front motor bearing is
received in a cavity formed in the cam shaft of the cam carrier that defines a bearing
pocket for the front motor bearing, with a ring gear mount 430 configured such that
the cam carrier bearing can be substantially radially aligned with corresponding end
portion(s) of stator windings of the motor assembly 410. The press fit of the front
motor bearing in the cavity formed in the cam shaft 129 of the carrier 126, with the
cam carrier bearing at least partially accommodated within a motor envelope of the
motor assembly 410, allows for a reduced overall length of the example power tool
400 (for example compared to the overall length of the power tool 100 described above
with respect to FIGs. 1A-1E) and/or an overall length that is less than or equal to
the overall length of the example power tool 200 shown in FIGs. 2A and 2B and/or the
example power tool 300 shown in FIGs. 3A and 3B.
[0088] The example motor assembly 410 includes a rotor 404 including magnets 406 mounted
in magnet pockets 407 formed in a rotor core 408 mounted on a rotor shaft 402. In
this internal permanent magnet configuration, the rotor magnets 406 are essentially
embedded in the rotor core 408. A stator assembly 411 is positioned around the rotor
404. The stator assembly 411 includes a stator core 412 having a series of teeth projecting
radially inward from the stator core 412, and a series of conductive windings 413
wound around the stator teeth. As the phases of the stator assembly 411 are sequentially
energized, they interact with the rotor magnets 406 to cause rotation of the rotor
404 relative to the stator assembly 411.
[0089] In the example shown in FIGs. 4A and 4B, the ring gear mount 430 includes a cylindrical
or rim-shaped portion 433, and a radial portion 434 extending radially outward from
a first axial end portion of the rim-shaped portion 433. An outer rim portion or a
lip 431 projects axially forward from the radial portion 434, for coupling with a
corresponding portion of the transmission housing portion 191 and/or the tool housing
190, and for receiving and supporting a component of the transmission assembly 120,
such as the ring gear 123.
[0090] In the example arrangement shown in FIGs. 4A and 4B, a front motor bearing 456 is
received within the cavity 121 formed in the cam shaft 129 of the carrier 126 that
defines the bearing pocket in the cam shaft 129. In particular, in this example arrangement,
the front motor bearing 456 is fitted on an end portion of the pinion forming the
sun gear 122, and is press fit within the walls of the cavity 121. In this example,
the rim-shaped portion 433 (for example, together with corresponding portions of the
rear carrier plate 126A and the rearward projection 127 of the carrier 126) defines
a bearing pocket 432 in which a cam carrier bearing 454 is received. Thus, in this
example arrangement, the cam carrier bearing 454 remains radially aligned with the
conductive windings 413 of the stator assembly 411, at least partially received within
the motor envelope 480, while the front motor bearing 456 has been positioned axially
forward (for example, compared to the position of the front motor bearing 356 shown
in FIGs. 3A and 3B).
[0091] Axial movement of the front motor bearing 456 in this manner makes additional space
available in the area of the cam carrier bearing 454. In some examples, this additional
space may be used to accommodate a larger, more robust cam carrier bearing 454, increasing
surface area contact between the cam carrier cam carrier bearing 454 and the ring
gear mount 430. In some examples, this additional space may be used to accommodate
an increase in size of the rim-shaped portion 433 of the ring gear mount 430, to provide
more robust support to the cam carrier bearing 454. In some examples, this additional
space may be used to accommodate both a larger cam carrier bearing 454 and also a
larger rim-shaped portion 433 of the ring gear mount 430. A more robust cam carrier
bearing 454 and/or more robust support of the cam carrier bearing 454 (by a larger
rim-shaped portion 433 of the ring gear mount 430) may provide improved resistance
to axial rearward movement of the impact mechanism 140 during operation of the example
power tool 400 in the impact mode of operation, i.e., rearward axial movement of the
impact mechanism 140 toward/into the motor envelope 480. In some examples, a more
robust cam carrier bearing 454 and/or more robust support of the cam carrier bearing
454 (by a larger rim-shaped portion 433 of the ring gear mount 430) may direct forces
generated due to operation of the impact mechanism 140 back into the housing 190 via
the ring gear mount 430, thus reducing vibration experienced by the user operating
the power tool 400 in the impact mode of operation.
[0092] In this example arrangement, the outer race of the cam carrier bearing 454 is supported
by the rim-shaped portion 433 of the ring gear mount 430, which is fixed to the housing
190 and thus remains substantially stationary. The inner race of the cam carrier bearing
454 is supported on the rearward projection 127 of the carrier 126, such that the
inner race of the cam carrier cam carrier bearing 454 rotates together with the carrier
126, while the outer race of the cam carrier bearing 454 remains substantially stationary.
[0093] In the example arrangement shown in FIGs. 4A and 4B, the press fit of the front motor
bearing 456 bearing pocket defined in the cavity 121 of the cam shaft 129 limits axial
movement of the front motor bearing 456 relative to the carrier 126. The inner race
of the front motor bearing 456 is fitted on a distal end portion of the pinion that
is coupled on the rotor shaft 402, and that includes the sun gear 122, such that the
inner race of the front motor bearing 456 rotates together with/at substantially the
same rotational speed as the rotor shaft 402/sun gear 122. The outer race of the front
motor bearing 456 is press fit in the bearing pocket defined in the cavity 121 formed
in the cam shaft 129, such that the outer race of the front motor bearing 456 rotates
together with/at substantially the same rotational speed as the carrier 126. Thus,
the outer race of the front motor bearing 456 rotates at a slower speed than the inner
race of the front motor bearing 456.
[0094] In the example arrangement shown in FIGs. 4A and 4B, a rear motor bearing 458 is
supported by the tool cap 198 coupled to the rear end portion of the tool housing
190. In some examples, a fan 418 is mounted on the rotor shaft 402 to rotate with
the motor assembly 410. In some examples, the fan 418 includes a radial main body
and a plurality of blades facing the stator assembly 411. In some examples, an inner
portion of the fan 418 is recessed to allow the rear motor bearing 458 to be at least
partially nested in the axial direction within the fan 418, and to be radially aligned
with the main body of the fan 418. The bearing pocket defined by the tool cap 198
may be axially received within the recessed portion of the fan 418, around the rear
motor bearing 458, so that positioning of the rear motor bearing 458 within the rear
tool cap 198 does not pose a significant increase in the overall length of the motor
assembly 410.
[0095] In the example arrangement shown in FIGs. 4A and 4B, the front motor bearing 456
has been moved axially forward, to a position within the cavity 121 of the cam shaft
129. The cam carrier bearing 454 and the rearward projecting rim-shaped portion 433
of the ring gear mount 430 are substantially radially aligned with the conductive
windings 413, and at least partially received within the motor envelope 480 of the
motor assembly 410. As with the example motor assemblies 210, 310 described above
with respect to FIGs. 2A-3B, the motor envelope 480 may be bounded by a rear plane
482 at a rearmost portion of the motor assembly 410 (i.e., at the rearmost portion
of the stator assembly 411), a front plane 484 at a frontmost portion of the motor
assembly 410, and a generally cylindrical boundary 486 extending from the rear plane
482 to the front plane 484 and surrounding a radially outermost portion of the motor
assembly 410 (e.g., a radially outermost portion of the stator assembly 411). The
motor envelope 480 may have a length L4 from the rear plane 482 to the front plane
484 and a diameter D4 of the cylindrical boundary 486. In some examples, the length
L4 associated with the motor assembly 410 shown in FIGs. 4A and 4B may be less than
or equal to the length L2 associated with the motor assembly 210 shown in FIGs. 2A
and 2B and/or the length L3 associated with the motor assembly 310 shown in FIGs.
3A and 3B. In some examples, the diameter D4 associated with the motor assembly 410
shown in FIGs. 4A and 4B may be less than or equal to the diameter D2 associated with
the motor assembly 210 shown in FIGs. 2A and 2B and/or the diameter D3 associated
with the motor assembly 310 shown in FIGs. 3A and 3B.
[0096] In some implementations, the length L4 of the example motor assembly 410 may be between
approximately 16.5 mm and 20.1 mm. In some examples, the length L4 may be smaller
than or equal to approximately 18.3 mm. In some implementations, the diameter D4 of
the example power tool 400 may be between approximately 46.0 mm and 56.0 mm. In some
examples, the diameter D4 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 400 may be
between approximately 89.6 mm and 109.0 mm. In some examples, the overall axial length
of the example power tool 400 may be smaller than or equal to approximately 99.5 mm.
In some implementations, an overall girth of the example power tool 400 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 400 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 410 (i.e., frontmost
part of the conductive windings 413) to a rear end portion of the carrier 126 i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 3.0 mm and
5.0 mm. In some examples, the axial length from the front end portion of the motor
assembly 410 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 4.5 mm, preferably smaller than or equal to approximately 4.1 mm, more
preferably smaller than or equal to approximately 3.7 mm. In some implementations,
an axial length from a rear end portion of the motor assembly 410 to a front end portion
of the tool holder 170 is between approximately 84.9 mm and 103.8 mm. In some examples,
the axial length from the rear end portion of the motor assembly 410 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 93.4
mm. In some implementations, an inner diameter of the ring gear mount 430 is between
approximately 21.5 mm and 26.4 mm. In some examples, the inner diameter of the ring
gear mount 430 is smaller than or equal to approximately 24.0 mm. In some implementations,
an outer diameter of the ring gear mount 430 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 430 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 410
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 410 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 410 is greater than or equal
to approximately 440 W when using a 20V max battery pack, with current drawn by the
motor assembly 410 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 400, a ratio of the maximum power output of the motor assembly 410 to the
axial length from the front end portion of the motor assembly 410 to the rear end
portion of the carrier 126 is greater than or equal to approximately 97.5 W/mm, preferably
greater than or equal to approximately 102 W/mm, more preferably greater than or equal
to approximately 107 W/mm. In some implementations, an output torque of the example
power tool 400 is between approximately 1642.0 in-lbs and 2007 in-lbs when using a
20V max battery pack. In some examples, the output torque of the example power tool
400 is greater than or equal to approximately 1825 in-lbs when using a 20V max battery
pack. In some examples, the output torque of the example power tool 400 is greater
than or equal to 2400 in-lbs.
[0097] FIGs. 5A and 5B present an example power tool 500, in accordance with implementations
described herein. In particular, FIG. 5A is a partial cross-sectional view of internal
components of the example power tool 500, and FIG. 5B is a zoomed-in partial cross-sectional
view of the internal components of the example power tool 500.
[0098] The example power tool 500 shown in FIGs. 5A and 5B includes a motor assembly 510
and a fan 518 that are physically configured to provide for a reduced overall length
and/or girth of the power tool 500 (for example, compared to an overall length and/or
girth of the example power tool 100 described above with respect to FIGs. 1A-1E).
Many features of the example power tool 500 are similar to features of the example
power tool 100 described above with respect to FIGs. 1A-1E and/or the example power
tool 200 described above with respect to FIGs. 2A and 2B, and/or the example power
tool 300 described above with respect to FIGs. 3A and 3B, and/or the example power
tool 400 described above with respect to FIGs. 4A and 4B, and thus, duplicative detailed
description thereof will not be repeated except as necessary.
[0099] In the example shown in FIGs. 5A and 5B, the motor assembly 510 includes a solid
core rotor configuration (rather than the open core rotor configuration described
above with respect to FIGs. 1C-2B), with an embedded magnet configuration (rather
than the surface mounted ring configuration described above with respect to FIGs.
2A and 2B). The solid core rotor configuration including the embedded magnets of the
example motor assembly 510 shown in FIGs. 5A and 5B does not provide for an annular
recess in the rotor core, in which the front motor bearing and/or the rear motor bearing
and/or the cam carrier bearing can be accommodated. Rather, in the example motor assembly
510 shown in FIGs. 5A and 5B, the front motor bearing is received in a cavity formed
in a central portion of the fan 518, such that the front motor bearing can be substantially
radially aligned with corresponding end portion(s) of stator winding(s) of the motor
assembly 510, and accommodated within a motor envelope of the motor assembly 510.
In the example motor assembly 510 shown in FIGs. 5A and 5B, the front motor bearing
and the cam carrier bearing are mounted on a corresponding rearward protrusion of
the cam carrier, so that the cam carrier bearing is supported be the ring gear mount
and substantially radially aligned with corresponding blades of the fan 518. This
arrangement allows for a reduced overall length of the example power tool 500 (for
example compared to the overall length of the power tool 100 described above with
respect to FIGs. 1A-1E) and/or an overall length that is less than or equal to the
overall length of the example power tool 200 shown in FIGs. 2A and 2B and/or the example
power tool 300 shown in FIGs. 3A and 3B and/or the example power tool 400 shown in
FIGs. 4A and 4B.
[0100] The example motor assembly 510 includes a rotor 504 including magnets 506 mounted
in magnet pockets 507 formed in a rotor core 508 mounted on a rotor shaft 502. In
this internal permanent magnet configuration, the rotor magnets 506 are essentially
embedded in the rotor core 508. A stator assembly 511 is positioned around the rotor
504, including a stator core 512 and a series of conductive windings 513. The ring
gear mount 530 includes a cylindrical or rim-shaped portion 533, and a radial portion
534 extending radially outward from a first axial end portion of the rim-shaped portion
533. An outer rim portion or a lip 531 projects axially forward from the radial portion
534.
[0101] In the example arrangement shown in FIGs. 5A and 5B, the fan 518 is coupled to the
rotor shaft 502 via a pinion 515. The fan 518 includes a plurality of blades 519 extending
radially outward from a contoured central hub portion 517 between the conductive windings
513 and the radial portion 534, the central hub portion 517 defining a recessed portion
of the fan 518. In the example arrangement shown in FIGs. 5A and 5B, a front motor
bearing 556 is received within the recess defined by the central hub portion 517 of
the fan 518. Thus, in this example arrangement, the front motor bearing 556 received
in the central hub portion 517 of the fan 518 remains radially aligned with the conductive
windings 513 of the stator assembly 511, and may be accommodated within a motor envelope
580 of the motor assembly 510. In this example arrangement, the fan 518 (mounted on
the rotor shaft 502 via the pinion 515) pilots, or provides support to, or supports
a relative position of the rotor 504 and the front motor bearing 556.
[0102] In this example arrangement, an inner race of the front motor bearing 556 is mounted
on the rearward projection 127 of the carrier 126, thus rotating together with the
carrier 126. In this example arrangement, the rearward projection 127 of the carrier
126 extends sufficiently rearward so that the front motor bearing 556 can be mounted
thereon. That is, in this example arrangement, the rearward projection 127 may be
somewhat elongated, compared to the example arrangements shown in, for example, FIGs.
2A-4B. In the example arrangement shown in FIGs. 5A and 5B, the outer race of the
front motor bearing 556 may abut a sidewall portion of the contoured central hub portion
517 of the fan 518, such that the outer race rotates together with the fan 518. In
some examples, rotation of the inner race of the 556 with the carrier 126, and rotation
of the outer race of the front motor bearing 556 with the fan 518 may produce a differential
in rotational speeds between the inner race and the outer race of the front motor
bearing 556. For example, the outer race may rotate at a slower speed than the inner
race of the front motor bearing 556.
[0103] In the example arrangement shown in FIGs. 5A and 5B, a cam carrier bearing 554 is
mounted on the rearward projection 127 of the carrier 126, supported by the cylindrical
or rim-shaped portion 533 of the ring gear mount 530 fixed to the housing 190. In
this example arrangement, an inner race of the cam carrier bearing 554 is mounted
on the rearward projection 127 of the carrier 126, thus rotating together with the
carrier 126. In this example arrangement, the outer race of the cam carrier bearing
554 may abut the cylindrical or rim-shaped portion 533 of the ring gear mount 530,
which is in turn fixed to the housing 190. Thus, the inner race of the cam carrier
bearing 554 rotates together with the carrier 126, while the outer race of the cam
carrier bearing 554 remains substantially stationary. In this example arrangement,
the cam carrier bearing 554 and the front motor bearing 556 are axially aligned, with
both the cam carrier bearing 554 and the front motor bearing 556 being mounted on
the carrier 126, and the cam carrier bearing 554 being radially aligned at least partially
with the blades 519 of the fan 518.
[0104] In the example arrangement shown in FIGs. 5A and 5B, a rear motor bearing 558 is
supported by the tool cap 198 coupled to the rear end portion of the tool housing
190. Axial movement of the fan 518, to a position that is axially forward of the rotor
504, shifts the rotor 504 axially rearward, allowing the front motor bearing 556 to
be received in the contoured central hub portion 517 of the fan 518, and within the
motor envelope 580 of the motor assembly 510, e.g., in radial alignment with the conductive
windings 513. As with the example motor assemblies 210, 310, 410 described above with
respect to FIGs. 2A-4B, the motor envelope 580 may be bounded by a rear plane 582
at a rearmost portion of the motor assembly 510 (i.e., at the rearmost portion of
the stator assembly 511), a front plane 584 at a frontmost portion of the motor assembly
510, and a generally cylindrical boundary 586 extending from the rear plane 582 to
the front plane 584 and surrounding a radially outermost portion of the motor assembly
510 (e.g., a radially outermost portion of the stator assembly 511). The motor envelope
580 may have a length L5 from the rear plane 582 to the front plane 584 and a diameter
D5 of the cylindrical boundary 586. In some examples, the length L5 associated with
the motor assembly 510 shown in FIGs. 5A and 5B may be less than or equal to the length
L2 associated with the motor assembly 210 shown in FIGs. 2A and 2B and/or the length
L3 associated with the motor assembly 310 shown in FIGs. 3A and 3B and/or the length
L4 associated with the motor assembly 410 shown in FIGs. 4A and 4B. In some examples,
the diameter D5 associated with the motor assembly 510 shown in FIGs. 5A and 5B may
be less than or equal to the diameter D2 associated with the motor assembly 210 shown
in FIGs. 2A and 2B and/or the diameter D3 associated with the motor assembly 310 shown
in FIGs. 3A and 3B and/or the diameter D4 associated with the motor assembly 410 shown
in FIGs. 4A and 4B.
[0105] In some implementations, the length L5 of the example motor assembly 510 may be between
approximately 16.6 mm and 20.2 mm. In some examples, the length L5 may be smaller
than or equal to approximately 18.4 mm. In some implementations, the diameter D5 of
the example power tool 500 may be between approximately 45.9 mm and 56.1 mm. In some
examples, the diameter D5 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 500 may be
between approximately 88.8 mm and 108.6 mm. In some examples, the overall axial length
of the example power tool 500 may be smaller than or equal to approximately 98.7 mm.
In some implementations, an overall girth of the example power tool 500 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 500 may be smaller than or equal to approximately 66.0 mm. an axial length
from a front end portion of the motor assembly 510 (i.e., frontmost part of the conductive
windings 513) to a rear end portion of the carrier 126 i.e., rearmost part of the
rear carrier plate 126A) is between approximately 5.0 mm and 8.0 mm. In some examples,
the axial length from the front end portion of the motor assembly 510 to the rear
end portion of the carrier 126 is smaller than or equal to approximately 7.7 mm, preferably
smaller than or equal to approximately 7.3 mm, more preferably smaller than or equal
to approximately 6.9 mm. In some implementations, an axial length from a rear end
portion of the motor assembly 510 to a front end portion of the tool holder 170 is
between approximately 84.4 mm and 103.2 mm. In some examples, the axial length from
the rear end portion of the motor assembly 510 to the front end portion of the tool
holder 170 is smaller than or equal to approximately 93.8 mm. In some implementations,
an inner diameter of the ring gear mount 530 is between approximately 16.2 mm and
21.6 mm. In some examples, the inner diameter of the ring gear mount 530 is smaller
than or equal to approximately 18.0 mm. In some implementations, an outer diameter
of the ring gear mount 530 is between approximately 46.8 mm and 57.2 mm. In some examples,
the outer diameter of the ring gear mount 530 is smaller than or equal to approximately
52.0 mm. In some examples, a maximum operating voltage of the removeable power tool
battery pack coupled to the power tool is in the range of approximately 20V to 80V,
and a nominal voltage of the battery pack is in the range of 18V to 72V. In some examples,
a maximum output power of the motor assembly 510 is between approximately 396.0 W
and 484.0 W when using a 20V battery pack, with a current drawn by the motor assembly
510 between approximately 22.0 amps and 27.0 amps. In some examples, the output power
of the motor assembly 510 is greater than or equal to approximately 440 W when using
a 20V max battery pack, with current drawn by the motor assembly 510 being greater
than or equal to approximately 24.5 amps. Thus, in power tool 500, a ratio of the
maximum power output of the motor assembly 510 to the axial length from the front
end portion of the motor assembly 510 to the rear end portion of the carrier 126 is
greater than or equal to approximately 53.1 W/mm, preferably greater than or equal
to approximately 55.6 W/mm, more preferably greater than or equal to approximately
58.4 W/mm. In some implementations, an output torque of the example power tool 500
is between approximately 1642.0 in-lbs and 2007 in-lbs when using a 20V max battery
pack. In some examples, the output torque of the example power tool 500 is greater
than or equal to approximately 1825 in-lbs when using a 20V max battery pack. In some
examples, the output torque of the example power tool 500 is greater than or equal
to 2400 in-lbs.
[0106] FIGs. 6A and 6B present an example power tool 600, in accordance with implementations
described herein. In particular, FIG. 6A is a partial cross-sectional view illustrating
internal components of the example power tool 600, and FIG. 6B is a zoomed-in partial
cross-sectional view of the internal components of the example power tool 600.
[0107] The example power tool 600 shown in FIGs. 6A and 6B includes a motor assembly 610,
a fan 618, and a ring gear mount 630 that are physically configured to provide for
a reduced overall length and/or girth of the power tool 600 (for example, compared
to an overall length and/or girth of the power tool 100 described above with respect
to FIGs. 1A-1E). Many features of the example power tool 600 are similar to features
of the power tool 100 described above with respect to FIGs. 1A-1E and/or the example
power tools 200, 300, 400, 500 described above with respect to FIGs. 2A-5B. Thus,
duplicative detailed description thereof will not be repeated except as necessary.
[0108] In the example shown in FIGs. 6A and 6B, the motor assembly 610 includes a solid
core rotor configuration (rather than the open core rotor configuration described
above with respect to FIGs. 1C-2B), with an embedded magnet configuration (rather
than the surface mounted ring configuration described above with respect to FIGs.
2A and 2B). As described above, the solid core rotor configuration/embedded magnet
configuration of rotor does not provide for an annular recess in which the front motor
bearing and/or the rear motor bearing and/or the cam carrier bearing can be accommodated.
Rather, in the example motor assembly 610 shown in FIGs. 6A and 6B, the front motor
bearing is received in a cavity formed in a central portion of the fan 618, such that
the front motor bearing can be substantially radially aligned with corresponding end
portion(s) of stator winding(s) of the motor assembly 610, and accommodated within
a motor envelope of the motor assembly 610. This axial shifting of the motor assembly
610 and the fan 618, and positioning of the front motor bearing within a cavity defined
by the fan, allows for a reduced overall length of the example power tool 600 (for
example compared to the overall length of the power tool 100 described above with
respect to FIGs. 1A-1E) and/or an overall length that is less than or equal to the
overall length(s) of the example power tools 200, 300, 400, 500 shown in FIGs. 2A-5B.
[0109] The example motor assembly 610 includes a rotor 604 including magnets 606 mounted
in magnet pockets 607 formed in a rotor core 608 mounted on a rotor shaft 602. In
this internal permanent magnet configuration, the rotor magnets 606 are essentially
embedded in the rotor core 608. A stator assembly 611 is positioned around the rotor
604, including a stator core 612 and a series of conductive windings 613. The ring
gear mount 630 includes a cylindrical or rim-shaped portion 633, and a radial portion
634 extending radially outward from a first axial end portion of the rim-shaped portion
633. An outer rim portion or a lip 631 projects axially forward from the radial portion
634. A rear projection 635 projects axially rearward from a second end portion of
the rim-shaped portion 633 of the ring gear mount 630, with a tab 637 projecting radially
inward.
[0110] In the example arrangement shown in FIGs. 6A and 6B, the fan 618 is coupled to the
rotor shaft 602 via a pinion 615. The fan 618 includes a plurality of blades 619 extending
radially outward from a contoured central hub portion 617, the central hub portion
617 defining a recessed portion of the fan 618. In this example, a portion of the
contour of the ring gear mount 630 follows, or corresponds to, a contour of a corresponding
portion of the fan 618.
[0111] In the example arrangement shown in FIGs. 6A and 6B, a front motor bearing 656 is
received within a bearing pocket 657 defined by the recess formed in the central hub
portion 617 of the fan 618, together with the rear projection 635 and tab 637 of the
ring gear mount 630. Thus, in this example arrangement, the front motor bearing 656
received in the bearing pocket 657 (defined by the central hub portion 617 of the
fan 618 and the rear projection 635 of the ring gear mount 630) remains radially aligned
with the conductive windings 613 of the stator assembly 611, and may be accommodated
at least partially or predominantly within a motor envelope 680 of the motor assembly
610. In this example arrangement, the tab 637 of the ring gear mount 630 provides
an axial stop for support of the front motor bearing 656.
[0112] In this example arrangement, an inner race of the front motor bearing 656 is mounted
on the rotor shaft 602, thus rotating together with the rotor shaft 602. The outer
race of the front motor bearing 656 may abut the rear projection 635 of the ring gear
mount 630, which is fixed to the housing 190 and thus remains substantially stationary.
Accordingly, the inner race of the front motor bearing 656 rotates together with the
rotor shaft 602, while the outer race of the front motor bearing 656 remains substantially
stationary.
[0113] In the example arrangement shown in FIGs. 6A and 6B, a cam carrier bearing 654 is
received within a bearing pocket 659 defined by the rear carrier plate 126A and the
rearward projection 127 of the carrier 126 together with the rim-shaped portion 633
of the ring gear mount 630. In this example arrangement, the cam carrier bearing 654
is radially aligned with the blades 619 of the fan 618. In this example arrangement,
an inner race of the cam carrier bearing 654 is mounted on the rearward projection
127 of the carrier 126, thus rotating together with the carrier 126. An outer race
of the cam carrier bearing 654 may abut the cylindrical or rim-shaped portion 633
of the ring gear mount 630, which is in turn fixed to the housing 190. Thus, the inner
race of the cam carrier bearing 654 rotates together with the carrier 126, while the
outer race of the cam carrier bearing 654 remains substantially stationary.
[0114] In the example arrangement shown in FIGs. 6A and 6B, a rear motor bearing 658 is
supported by the tool cap 198 coupled to the rear end portion of the tool housing
190. Axial location of the fan 618 at a position that is axially forward of the rotor
604, where the central hub portion 617 penetrates within the body of the motor to
approximately a front axial end of the stator core 612, allows the front motor bearing
656 to be received in the bearing pocket 657, and at least partially or predominantly
within the motor envelope 680 of the motor assembly 610. As with the example motor
assemblies 210, 310, 410, 510 described above with respect to FIGs. 2A-5B, the motor
envelope 680 may be bounded by a rear plane 682 at a rearmost portion of the motor
assembly 610 (i.e., at the rearmost portion of the stator assembly 611), a front plane
684 at a frontmost portion of the motor assembly 610, and a generally cylindrical
boundary 686 extending from the rear plane 682 to the front plane 684 and surrounding
a radially outermost portion of the motor assembly 610 (e.g., a radially outermost
portion of the stator assembly 611). The motor envelope 680 may have a length L6 from
the rear plane 682 to the front plane 684 and a diameter D6 of the cylindrical boundary
686. In some examples, the length L6 associated with the motor assembly 610 shown
in FIGs. 6A and 6B may be less than or equal to the length L2 associated with the
motor assembly 210 shown in FIGs. 2A and 2B and/or the length L3 associated with the
motor assembly 310 shown in FIGs. 3A and 3B and/or the length L4 associated with the
motor assembly 410 shown in FIGs. 4A and 4B and/or the length L5 associated with the
motor assembly 510 shown in FIGs. 5A and 5B. In some examples, the diameter D6 associated
with the motor assembly 610 shown in FIGs. 6A and 6B may be less than or equal to
the diameter D2 associated with the motor assembly 210 shown in FIGs. 2A and 2B and/or
the diameter D3 associated with the motor assembly 310 shown in FIGs. 3A and 3B and/or
the diameter D4 associated with the motor assembly 410 shown in FIGs. 4A and 4B and/or
the diameter D5 associated with the motor assembly 510 shown in FIGs. 5A and 5B. In
an example, the front motor bearing 656 is radially aligned at least in part with
the rear projection 635 of the ring gear mount 630, the central hub portion 617 of
the fan 618, and a front end of the conductive windings 613.
[0115] In some implementations, the length L6 of the example motor assembly 610 may be between
approximately 16.6 mm and 20.2 mm. In some examples, the length L6 may be smaller
than or equal to approximately 18.4 mm. In some implementations, the diameter D6 of
the example power tool 600 may be between approximately 45.9 mm and 56.1 mm. In some
examples, the diameter D6 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 600 may be
between approximately 88.8 mm and 108.6 mm. In some examples, the overall axial length
of the example power tool 600 may be smaller than or equal to approximately 98.7 mm.
In some implementations, an overall girth of the example power tool 600 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 600 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 610 (i.e., frontmost
part of the conductive windings 613) to a rear end portion of the carrier 126 i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 6.7 mm and
8.9 mm. In some examples, the axial length from the front end portion of the motor
assembly 610 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 8.5 mm, preferably smaller than or equal to approximately 8.1 mm, more
preferably smaller than or equal to approximately 7.7 mm. In some implementations,
an axial length from a rear end portion of the motor assembly 610 to a front end portion
of the tool holder 170 is between approximately 84.5 mm and 103.3 mm. In some examples,
the axial length from the rear end portion of the motor assembly 610 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 93.8
mm. In some implementations, an inner diameter of the ring gear mount 630 is between
approximately 21.5 mm and 26.4 mm. In some examples, the inner diameter of the ring
gear mount 630 is smaller than or equal to approximately 24.0 mm. In some implementations,
an outer diameter of the ring gear mount 630 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 630 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 610
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 510 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 610 is greater than or equal
to approximately 440 W when using a 20V max battery pack, with current drawn by the
motor assembly 510 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 600, a ratio of the maximum power output of the motor assembly 610 to the
axial length from the front end portion of the motor assembly 610 to the rear end
portion of the carrier 126 is greater than or equal to approximately 47.2 W/mm, preferably
greater than or equal to approximately 49.5 W/mm, more preferably greater than or
equal to approximately 51.9 W/mm. In some implementations, an output torque of the
example power tool 600 is between approximately 1642.0 in-lbs and 2007 in-lbs when
using a 20V max battery pack. In some examples, the output torque of the example power
tool 600 is greater than or equal to approximately 1825 in-lbs when using a 20V max
battery pack. In some examples, the output torque of the example power tool 600 is
greater than or equal to 2400 in-lbs.
[0116] FIGs. 7A-7L illustrate features of an example power tool 700, in accordance with
implementations described herein. The example power tool 700 includes a motor assembly
710 having a shaftless rotor structure. The shaftless rotor structure may provide
for modular assembly of the front motor bearing and the cam carrier bearing with the
cam assembly, thus facilitating assembly of the example power tool 700, while still
maintaining a reduced overall length and/or girth of the example power tool 700. The
shaftless rotor structure of the motor assembly 710 includes an integrated fan interlocking
structure, that allows the fan to rotate together with the rotor structure, without
connection to a rotor shaft. Some features of the example power tool 700 are similar
to features of the example power tool 100 described above with respect to FIGs. 1A-1E
and/or the example power tools 200, 300, 400, 500, 600 described above with respect
to FIGs. 2A-6B. Accordingly, duplicative detailed description thereof will not be
repeated except as necessary.
[0117] FIG. 7A is a partial cross-sectional view, illustrating internal components of the
example power tool 700, and FIG. 7B is a zoomed-in partial cross-sectional view of
the internal components of the example power tool 700. As shown in FIGs. 7A and 7B,
the example power tool 700 includes a motor assembly 710 and a ring gear mount 730
that are physically configured to provide for a reduced overall length and/or girth
of the power tool 700 (for example, compared to an overall length and/or girth of
the power tool 100 described above with respect to FIGs. 1A- 1E). The motor assembly
710 includes a solid core rotor configuration, with embedded magnets.
[0118] As described above, the solid core rotor configuration including the embedded magnets
does not form an annular recess in which the front motor bearing and/or the rear motor
bearing and/or the cam carrier bearing can be accommodated. Rather, the example motor
assembly 710 includes a ring gear mount 730 configured such that a front motor bearing
can be radially aligned with a cam carrier bearing, and for both the front motor bearing
and the cam carrier bearing to be substantially radially aligned with corresponding
end portion(s) of stator windings of the motor assembly 710. In the example arrangement
shown in FIGs. 7A and 7B, the cam carrier indexes, or sets a location for, or supports,
a position of the front motor bearing. The configuration of the ring gear mount 730
allows for a reduced overall length of the example power tool 700 (for example compared
to the overall length of the power tool 100 described above with respect to FIGs.
1A-1E) and/or an overall length that is less than or equal to the overall length of
the example power tools 200, 300, 400, 500, 600 shown in FIGs. 2A-6B.
[0119] The example motor assembly 710 includes a rotor 704 including magnets 706 mounted
in magnet pockets 707 formed in a rotor core 708. A stator assembly 711 positioned
around the rotor 704 includes a stator core 712 including a series of conductive windings
713. As the phases of the stator assembly 711 are sequentially energized, they interact
with the rotor magnets 706 to cause rotation of the rotor 704 relative to the stator
assembly 711.
[0120] The ring gear mount 730 includes a cylindrical or rim-shaped portion 733, and a radial
portion 734 extending radially outward from the rim-shaped portion 733 of the ring
gear mount 730. The ring gear mount 730 includes an outer rim portion or a lip 731
projecting axially forward from the radial portion 734, for coupling with a corresponding
portion of the housing 190. The rim-shaped portion 733 (for example, together with
corresponding portions of the rear carrier plate 126A and the rearward projection
127 of the carrier 126) defines a bearing pocket 732 in which a cam carrier bearing
754 is received. In this example arrangement, the cam carrier bearing 754 is supported
by the ring gear mount 730, and in particular, an outer race of the cam carrier bearing
754 is supported by the rim-shaped portion 733 of the ring gear mount 730. An inner
race of the cam carrier bearing 754 is supported on the rearward projection 127 of
the carrier 126, such that the inner race of the cam carrier bearing 754 rotates together
with the carrier 126.
[0121] In the example shown in FIGs. 7A and 7B, a drive pin 701 has a first end portion
that is fixedly coupled in the transmission assembly 120 during the manufacturing
of the transmission assembly 120, and a second end portion that is received and fixedly
coupled in the rotor 704 during the assembly of the motor and transmission into the
power tool housing 190. In particular, the first end portion of the drive pin 701
defines a gear portion 722 that functions as a sun gear in the transmission assembly
120. In an example, the gear portion 722 of the drive pin 701 is in meshed engagement
with the one or more planet gears 124 of the transmission assembly 120. The second
end portion projects rearwardly through the rearward projection 127 of the cam carrier
126 and out of the transmission assembly 120. A shaft portion 702 formed at the second
end portion of the drive pin 701 extends into an axial opening 703 formed in the rotor
704. In some examples, the shaft portion 702 of the drive pin 701 is press fit, or
interference fit, into the axial opening 703 in the rotor 704 during the assembly
step of the motor and transmission into the power tool housing 190. This ensures that
the drive pin 701 is rotationally fixed to the rotor 704 within the power tool 700.
In the example arrangement shown in FIGs. 7A and 7B, an axial length of the axial
opening 703 in the rotor 704 is greater than an axial length of the shaft portion
702 of the drive pin 701.
[0122] In this example arrangement, a front motor bearing 756 is mounted on the shaft portion
702 of the drive pin 701, and is piloted, or set in position by the rearward projection
127 of the rear carrier plate 126A of the carrier 126. In particular, the rearward
projection 127 is fitted between the front motor bearing 756 and the cam carrier bearing
754. In some examples, a rotor end cap 740, mounted on a front end of the rotor to
retain the rotor magnets 706 within the magnet pockets 707 of the rotor core 708,
may additionally engage a rear end of the front motor bearing 756, to provide for
axial support of the front motor bearing 756 in an axial direction away from the transmission
assembly 120. In this example arrangement, an outer race of the cam carrier bearing
754 is supported by the (stationary) ring gear mount 330, and an inner race of the
cam carrier bearing 754 is supported by, and rotates with, the rearward projection
127 of the carrier 126. An outer race of the front motor bearing 756 is supported
by the rearward projection 127 that rotates together with the carrier 126 and an inner
race of the front motor bearing 756 is supported by and rotates with the shaft portion
702 of the drive pin 701. That is, in this example, the outer race of the front motor
bearing 756 also rotates, but at a somewhat lower speed than the inner race of the
front motor bearing 756.
[0123] In some examples, a fan 750 may be coupled to the rotor 704, so as to rotate together
with the rotor 704. The fan 750 and/or the rotor 704 may include geometry that provides
for interlocking of the fan 750 and the rotor 704, allowing the fan 750 to rotate
together with the rotor 704, without the mounting of the fan 750 on a shaft extending
from the rotor 704. This interlocking of the fan 750 and the rotor 704, rather than
mounting the fan on a rotor shaft as is conventionally done, may facilitate the shaftless
rotor structure. In an embodiment, the fan 750 is mounted on a protruded portion 705
of the rotor 704. In some examples, the fan 750 is contoured to allow a rear motor
bearing 758, which is also seated on the protruded portion 705 of the rotor 704, to
be located within a recessed portion 757 of the fan 750 and in radial alignment with
at least a portion of the fan 750. In an embodiment, the rear motor bearing 758 is
axially and radially supported by the tool cap 198 coupled to the rear end portion
of the tool housing 190.
[0124] FIG. 7C is a perspective view of the rotor 704. FIG. 7D is a perspective view of
the fan 750 coupled to the rotor 704. FIG. 7E is a disassembled cross-sectional view,
and FIG. 7F is an assembled cross-sectional view, of the fan 750 and the rotor 704,
taken along line E-E of FIG. 7D.
[0125] As shown in FIGs. 7C-7F, the fan 750 includes a fan plate 752 having a central opening
755. In the assembled configuration, the protruded portion 705 of the rotor 704 is
received through the central opening 755 in the fan plate 752. In an example, the
protruded portion 705 includes a non-circular outer profile, in this example, with
a square or circular outer cross-section. The center opening 755 of the fan plate
752 includes a corresponding profile. This arrangement allows transfer of rotational
torque from the rotor 704 to the fan 750. The recessed portion 757 is formed on a
first side of the fan plate 752, surrounding the central opening 755, to accommodate
the rear motor bearing 758. The rear motor bearing 758 is received in the recessed
portion 757 defined in the fan plate 752, so that positioning of the rear motor bearing
358 at the rear tool cap 198 does not pose a significant increase in the overall length
of the motor assembly 710. A plurality of blades 751 are provided on a second side
of the fan plate 752, for generating axial airflow through the example power tool
700 during operation. In some examples, a plurality of protrusions 753 are provided
on the second side of the fan plate 752. The protrusions 753 may be positioned on
a portion of the second side of the fan plate 752 corresponding to the recessed portion
757. The protrusions 753 may be positioned so as to correspond to positions of the
magnet pockets 707 of the rotor 704 when the rotor 704 and the fan 750 are coupled.
In some examples, a shape, or a contour, of each of the plurality of protrusions 753
may correspond to a shape, or a contour, of a corresponding end portion 707A of a
magnet pocket 707 to which the protrusion 753 is to be coupled. Specifically, in an
example, protrusions 753 are provided in pairs, each pair including two protrusions
facing one another in a lateral direction and distance properly to fit into end portions
707A of a corresponding magnet pocket 707. Thus, the plurality of protrusions 753
may define geometric interlocking features that, together with the corresponding end
portions 707A of the magnet pockets 707, provide for interlocking and coupling of
the rotor 704 and the fan 750. This feature, alone or in cooperation with the protruded
portion 705, ensures that the fan 750 is rotationally fixed to the rotor 704. Furthermore,
in an example, each pair of protrusions 753 engages lateral sides of the rotor magnet
706 disposed within the corresponding magnet pocket 707 to mechanically retain the
magnet 706, and protect the magnet against wobble and vibration within the magnet
pocket 707.
[0126] FIG. 7G is an exploded perspective view, and FIG. 7H is an assembled perspective
view, of a drive assembly 770 including the drive pin 701, the front motor bearing
756, and the rotor end cap 740. FIG. 7I is a cross-sectional view taken along line
F-F of FIG. 7H. FIG. 7J is a partially assembled perspective view, and FIG. 7K is
an assembled view, of the fan 750, the rotor 704, and the drive assembly. FIG. 7L
is a cross-sectional view taken along line G-G of FIG. 7K.
[0127] As shown in FIGs. 7G-7K, the rotor end cap 740 includes a cap plate 742, with an
opening 745 defined by an annular flange formed at a central portion of the cap plate
742. The shaft portion 702 of the drive pin 701 is received through the front motor
bearing 756 and through the opening 745 in the central portion of the cap plate 742.
In some examples, a plurality of protrusions 743 are formed on a side of the cap plate
742 configured to face the rotor 704. The protrusions 743 may be positioned similarly
to, and in mirror opposite to, the protrusions 753 of the fan 750. In some examples,
a shape, or a contour, of each of the plurality of protrusions 743 may correspond
to a shape, or a contour, of a corresponding end portion 707B of a magnet pocket 707
to which the protrusion 743 is to be coupled. Thus, the plurality of protrusions 743
may define geometric interlocking features that, together with the corresponding end
portions 707B of the magnet pockets 707, provide for interlocking and coupling of
the rotor end cap 740 to the rotor 704. In an embodiment, the cap plate 742 may be
securely mounted on the shaft portion 702 of the drive pin 701 via, e.g., press-fitting,
so the rotor end cap 740 rotationally locks the drive pin 701 to the rotor 704.
[0128] The shaftless configuration of the rotor 704 provides for modular assembly of the
drive system of the example power tool 700.
[0129] In the example power tool 700, the front motor bearing 756 is substantially radially
aligned with the cam carrier bearing 754, and substantially radially aligned at least
a front end of with the conductive windings 713, and the front motor bearing 756 and
the cam carrier bearing 754 are at least partially received within a motor envelope
780 of the motor assembly 710. The motor envelope 780 may have a length L7 from the
rear plane to the front plane and a diameter D7 defining a cylindrical boundary. In
some examples, at least a portion of the front motor bearing 756 and at least a portion
of the cam carrier bearing 754 are received within the motor envelope 780. In some
examples, the length L7 associated with the motor assembly 710 of the example power
tool 700 may be less than or equal to the length L2 associated with the motor assembly
210 shown in FIGs. 2A and 2B and/or the length L3 associated with the motor assembly
310 shown in FIGs. 3A and 3B and/or the length L4 associated with the motor assembly
410 shown in FIGs. 4A and 4B and/or the length L5 associated with the motor assembly
510 shown in FIGs. 5A and 5B and/or the length L6 associated with the motor assembly
610 shown in FIGs. 6A and 6B. In some examples, the diameter D7 associated with the
motor assembly 710 of the example power tool 700 may be less than or equal to the
diameter D2 associated with the motor assembly 210 shown in FIGs. 2A and 2B and/or
the diameter D3 associated with the motor assembly 310 shown in FIGs. 3A and 3B and/or
the diameter D4 associated with the motor assembly 410 shown in FIGs. 4A and 4B and/or
the diameter D5 associated with the motor assembly 510 shown in FIGs. 5A and 5B and/or
the diameter D6 associated with the motor assembly 610 shown in FIGs. 6A and 6B.
[0130] In some implementations, the length L7 of the example motor assembly 710 may be between
approximately 16.5 mm and 20.1 mm. In some examples, the length L7 may be smaller
than or equal to approximately 18.3 mm. In some implementations, the diameter D7 of
the example power tool 700 may be between approximately 45.9 mm and 56.1 mm. In some
examples, the diameter D7 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 700 may be
between approximately 89.6 mm and 109.0 mm. In some examples, the overall axial length
of the example power tool 700 may be smaller than or equal to approximately 99.5 mm.
In some implementations, an overall girth of the example power tool 700 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 700 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 710 (i.e., frontmost
part of the conductive windings 713) to a rear end portion of the carrier 126 i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 3.2 mm and
5.2 mm. In some examples, the axial length from the front end portion of the motor
assembly 710 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 4.7 mm, preferably smaller than or equal to approximately 4.3 mm, more
preferably smaller than or equal to approximately 3.9 mm. In some implementations,
an axial length from a rear end portion of the motor assembly 710 to a front end portion
of the tool holder 170 is between approximately 84.9 mm and 103.8 mm. In some examples,
the axial length from the rear end portion of the motor assembly 710 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 93.4
mm. In some implementations, an inner diameter of the ring gear mount 730 is between
approximately 18.9 mm and 23.1 mm. In some examples, the inner diameter of the ring
gear mount 730 is smaller than or equal to approximately 21.0 mm. In some implementations,
an outer diameter of the ring gear mount 730 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 730 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 710
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 310 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 710 is less than or equal
to approximately 440 W when using a 20V max battery pack, with current drawn by the
motor assembly 710 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 700, a ratio of the maximum power output of the motor assembly 710 to the
axial length from the front end portion of the motor assembly 710 to the rear end
portion of the carrier 126 is greater than or equal to approximately 93.2 W/mm, preferably
greater than or equal to approximately 97.7 W/mm, more preferably greater than or
equal to approximately 103 W/mm. In some implementations, an output torque of the
example power tool 700 is between approximately 1642.0 in-lbs and 2007 in-lbs when
using a 20V max battery pack. In some examples, the output torque of the example power
tool 700 is greater than or equal to approximately 1825 in-lbs when using a 20V max
battery pack. In some examples, the output torque of the example power tool 700 is
greater than or equal to 2400 in-lbs.
[0131] FIGs. 8A and 8B present an example power tool 800, in accordance with implementations
described herein. In particular, FIG. 8A is a partial cross-sectional view illustrating
internal components of the example power tool 800, and FIG. 8B is a zoomed-in partial
cross-sectional view of the internal components of the example power tool 800. FIG.
8C is a perspective view of an example fan 850 of the example power tool 800.
[0132] The example power tool 800 shown in FIGs. 8A and 8B includes a motor assembly and
a ring gear mount that are physically configured to provide for a reduced overall
length and/or girth of the power tool (for example, compared to an overall length
and/or girth of the power tool 100 described above with respect to FIGs. 1A-1E), together
with the fitting of a front motor bearing within a bearing pocket defined in a cavity
formed within a cam shaft. Many features of the example power tool 800 are similar
to features of the power tool 100 described above with respect to FIGs. 1A-1E and/or
the example power tools 200, 300, 400, 500, 600, 700 described above with respect
to FIGs. 2A-7L. Thus, duplicative detailed description thereof will not be repeated
except as necessary.
[0133] In the example shown in FIGs. 8A and 8B, the motor assembly 810 includes a solid
core rotor configuration, with an embedded magnet configuration. As described above,
due to the solid core rotor configuration including the embedded, an annular recess
is not formed within the motor assembly 810 in which the front motor bearing and/or
the rear motor bearing and/or the cam carrier bearing can be accommodated. Rather,
in the example motor assembly 810 shown in FIGs. 8A and 8B, the front motor bearing
856 is received in a bearing pocket defined in a cavity 121 formed in the cam shaft
129 of the carrier 126, with a ring gear mount 830 configured such that the cam carrier
bearing 854 can be substantially radially aligned with corresponding end portion(s)
of stator windings of the motor assembly 810. In the example power tool 800 shown
in FIGs. 8A-8C, a geometric interlocking structure allows a fan 850 to be coupled
to and rotate together with a rotor 804 of the motor assembly 810. The press fit of
the front motor bearing 856 in the bearing pocket defined in the cavity 121 formed
in the cam shaft 129 of the carrier 126, with the cam carrier bearing 756 at least
partially accommodated within a motor envelope of the motor assembly 810, alone or
together with the geometric interlocking of the fan 850 and the rotor 804, allows
for a reduced overall length of the example power tool 800 (for example compared to
the overall length of the example power tool 100 described above with respect to FIGs.
1A-1E) and/or an overall length that is less than or equal to the overall length of
the example power tools 200, 300, 400, 500, 60, 700 shown in FIGs. 2A-7L.
[0134] The example motor assembly 810 includes a rotor 804 including magnets 806 mounted
in magnet pockets 807 formed in a rotor core 808 mounted on a rotor shaft 802. In
this internal permanent magnet configuration, the rotor magnets 806 are essentially
embedded in the rotor core 808. A stator assembly 811 is positioned around the rotor
804. The stator assembly 811 includes a stator core 812 having a series of teeth projecting
radially inward from the stator core 812, and a series of conductive windings 813
wound around the stator teeth. As the phases of the stator assembly 811 are sequentially
energized, they interact with the rotor magnets 806 to cause rotation of the rotor
804 relative to the stator assembly 811.
[0135] In the example shown in FIGs. 8A and 8B, the ring gear mount 830 includes a cylindrical
or rim-shaped portion 833, and a radial portion 834 extending radially outward from
a first axial end portion of the rim-shaped portion 833. An outer rim portion or a
lip 831 projects axially forward from the radial portion 834, for coupling with a
corresponding portion of the 8 tool housing 190, and for receiving and supporting
a component of the transmission assembly 120, such as the ring gear 123.
[0136] In the example arrangement shown in FIGs. 8A and 8B, the front motor bearing 856
is received within the bearing pocket defined by the cavity 121 formed in the cam
shaft 129 of the carrier 126. In particular, in this example arrangement, the front
motor bearing 856 is fitted on an end portion of the pinion forming the sun gear 122,
and is press fit within the walls of the cavity 121. In this example, the rim-shaped
portion 833 (for example, together with corresponding portions of the rear carrier
plate 126A and the rearward projection 127 of the carrier 126) defines a bearing pocket
832 in which the cam carrier bearing 854 is received. Thus, in this example arrangement,
the cam carrier bearing 854 remains radially aligned with at least the front end of
the conductive windings 813 of the stator assembly 811, at least partially received
within the motor envelope 880, while the front motor bearing 856 has been positioned
axially forward of the cam carrier bearing 854.
[0137] In some examples, axial position of the front motor bearing 856 in this manner provides
additional space available in the area of the cam carrier bearing 854. In some examples,
this additional space may be used to accommodate a larger, more robust cam carrier
bearing 854 as may be required by the torque and power output of the power tool, increasing
surface area contact between the cam carrier cam carrier bearing 854 and the ring
gear mount 830. In some examples, this additional space may be used to accommodate
an increase in size of the rim-shaped portion 833 of the ring gear mount 830, to provide
more robust support to the cam carrier bearing 854. In some examples, this additional
space may be used to accommodate both a larger cam carrier bearing 854 and also a
larger rim-shaped portion 833 of the ring gear mount 830. A more robust cam carrier
bearing 854 and/or more robust support of the cam carrier bearing 854 (by a larger
rim-shaped portion 833 of the ring gear mount 830) may provide improved resistance
to axial rearward movement of the impact mechanism 140 during operation of the example
power tool 800 in the impact mode of operation, i.e., rearward axial movement of the
impact mechanism 140 toward/into the motor envelope 880. In some examples, a more
robust cam carrier bearing 854 and/or more robust support of the cam carrier bearing
854 (by a larger rim-shaped portion 833 of the ring gear mount 830) may direct forces
generated due to operation of the impact mechanism 140 back into the housing 190 via
the ring gear mount 830, thus reducing vibration experienced by the user operating
the power tool 800 in the impact mode of operation. In an embodiment, a thickness
of the cam carrier bearing 854 as defined as the radial distance between its inner
and outer race is greater than or equal to approximately 30% of the radius of the
rotor core 808.
[0138] In this example arrangement, the outer race of the cam carrier bearing 454 is supported
by the rim-shaped portion 833 of the ring gear mount 830, which is fixed to the housing
190 and thus remains substantially stationary. The inner race of the cam carrier bearing
854 is supported on the rearward projection 127 of the carrier 126, such that the
inner race of the cam carrier bearing 854 rotates together with the carrier 126, while
the outer race of the cam carrier bearing 854 remains substantially stationary.
[0139] In the example arrangement shown in FIGs. 8A and 8B, the press fit of the front motor
bearing 856 in the bearing pocket defined by the cavity 121 of the cam shaft 129 limits
axial movement of the front motor bearing 856 relative to the carrier 126. The inner
race of the front motor bearing 856 is fitted on a distal end portion of the pinion
that is coupled on the rotor shaft 802, and that includes the sun gear 122, such that
the inner race of the front motor bearing 856 rotates together with/at substantially
the same rotational speed as the rotor shaft 402/sun gear 122. The outer race of the
front motor bearing 856 is press fit in the cavity 121 formed in the cam shaft 129,
such that the outer race of the front motor bearing 856 rotates together with/at substantially
the same rotational speed as the carrier 126. Thus, the outer race of the front motor
bearing 856 rotates at a slower speed than the inner race of the front motor bearing
856.
[0140] In some examples, a fan 850 may be coupled to the rotor 804, so as to rotate together
with the rotor 804. The fan 850 and/or the rotor 804 may include geometry that provides
for interlocking of the fan 850 and the rotor 804, such that the fan 850 rotates together
with the rotor 804. In an example, the fan 850 may be slip fit on the rotor shaft
802 without an intermediary bushing. The interlock mechanism described transmits rotational
torque from the rotor 804 to the fan 850 without a need to rigidly mount the fan 850
on the rotor shaft 802. In some examples, a rear motor bearing 858 is seated on a
rear end portion of the rotor shaft 802, within a recessed portion 857 of the fan
850, and axially supported by the tool cap 198 coupled to the rear end portion of
the tool housing 190.
[0141] As shown in 8C, the fan 850 includes a fan plate 852 having a central opening 855.
In the assembled configuration, the rotor shaft 802 is received through the central
opening 855 in the fan plate 852. A recessed portion 857 (see FIG. 8B) is formed on
a first side of the fan plate 852, surrounding the central opening 855, to accommodate
the rear motor bearing 858 together with the tool cap 198. This positioning of the
rear motor bearing 858 in the recessed portion 857 defined between the fan plate 852
and the tool cap 198 does not pose a significant increase in the overall length of
the motor assembly 810. A plurality of blades 851 are provided on a second side of
the fan plate 852, for generating axial airflow through the example power tool 800
during operation.
[0142] In some examples, a plurality of protrusions 853 are provided on the second side
of the fan plate 852. The protrusions 853 may be so as to correspond to positions
of the magnet pockets 807 of the rotor 804 when the rotor 804 and the fan 850 are
coupled. In some examples, a shape, or a contour, of each of the plurality of protrusions
853 may correspond to a shape, or a contour, of a corresponding magnet pocket 807
in which the protrusion 853 is to be received. As shown in FIGs. 8A and 8B, in some
examples, corresponding portions of the rotor core 808 extend beyond, or overhang,
a position of rear end portions of the magnets 806 received in the magnet pockets
807. That is, an axial length of the magnet pockets 807 may be greater than an axial
length of the corresponding magnets 806 received therein. Accordingly, in some examples,
the protrusions 853 are inserted into axial end portions of the corresponding magnet
pockets 807 not occupied by the magnets 806 received therein. Thus, the plurality
of protrusions 853 may define geometric interlocking features that, together with
the corresponding magnet pockets 807, provide for interlocking and coupling of the
rotor 804 and the fan 850, such that the fan 850 rotates together with the rotor 804.
[0143] In the example power tool 800, the front motor bearing 856 has been moved axially
forward, and the cam carrier bearing 854 is substantially radially aligned with the
conductive windings 813, so as to be at least partially received within a motor envelope
880. The motor envelope 880 may have a length L8 from the rear plane to the front
plane and a diameter D8 defining a cylindrical boundary. In some examples, the length
L8 associated with the motor assembly 810 of the example power tool 800 may be less
than or equal to the length L2 associated with the motor assembly 210 shown in FIGs.
2A and 2B and/or the length L3 associated with the motor assembly 310 shown in FIGs.
3A and 3B and/or the length L4 associated with the motor assembly 410 shown in FIGs.
4A and 4B and/or the length L5 associated with the motor assembly 510 shown in FIGs.
5A and 5B and/or the length L6 associated with the motor assembly 610 shown in FIGs.
6A and 6B and/or the length L7 associated with the motor assembly 710 shown in FIGs.
7A and 7B. In some examples, the diameter D8 associated with the motor assembly 810
of the example power tool 800 may be less than or equal to the diameter D2 associated
with the motor assembly 210 shown in FIGs. 2A and 2B and/or the diameter D3 associated
with the motor assembly 310 shown in FIGs. 3A and 3B and/or the diameter D4 associated
with the motor assembly 410 shown in FIGs. 4A and 4B and/or the diameter D5 associated
with the motor assembly 510 shown in FIGs. 5A and 5B and/or the diameter D6 associated
with the motor assembly 610 shown in FIGs. 6A and 6B and/or the diameter D7 associated
with the motor assembly 710 shown in FIGs. 7A and 7B.
[0144] In some implementations, the length L8 of the example motor assembly 810 may be between
approximately 16.5 mm and 20.1 mm. In some examples, the length L8 may be smaller
than or equal to approximately 18.2 mm. In some implementations, the diameter D8 of
the example power tool 800 may be between approximately 45.9 mm and 56.1 mm. In some
examples, the diameter 87 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 800 may be
between approximately 89.6 mm and 109.0 mm. In some examples, the overall axial length
of the example power tool 800 may be smaller than or equal to approximately 99.5 mm.
In some implementations, an overall girth of the example power tool 800 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 800 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 810 (i.e., frontmost
part of the conductive windings 813) to a rear end portion of the carrier 126 i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 2.6 mm and
4.2 mm. In some examples, the axial length from the front end portion of the motor
assembly 810 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 4.1 mm, preferably smaller than or equal to approximately 3.7 mm, more
preferably smaller than or equal to approximately 3.3 mm. In some implementations,
an axial length from a rear end portion of the motor assembly 810 to a front end portion
of the tool holder 170 is between approximately 84.3 mm and 103.3 mm. In some examples,
the axial length from the rear end portion of the motor assembly 710 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 92.8
mm. In some implementations, an inner diameter of the ring gear mount 730 is between
approximately 18.9 mm and 23.1 mm. In some examples, the inner diameter of the ring
gear mount 830 is smaller than or equal to approximately 21.0 mm. In some implementations,
an outer diameter of the ring gear mount 830 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 830 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 810
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 310 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 810 is greater than or equal
to approximately 440 W when using a 20V max battery pack, with current drawn by the
motor assembly 710 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 800, a ratio of the maximum power output of the motor assembly 810 to the
axial length from the front end portion of the motor assembly 810 to the rear end
portion of the carrier 126 is greater than or equal to approximately 109 W/mm, preferably
greater than or equal to approximately 114 W/mm, more preferably greater than or equal
to approximately 120 W/mm. In some implementations, an output torque of the example
power tool 800 is between approximately 1642.0 in-lbs and 2007 in-lbs when using a
20V max battery pack. In some examples, the output torque of the example power tool
800 is greater than or equal to approximately 1825 in-lbs when using a 20V max battery
pack. In some examples, the output torque of the example power tool 800 is greater
than or equal to 2400 in-lbs.
[0145] FIG. 9 presents an example power tool 900, in accordance with implementations described
herein. In particular, FIG. 9 is a partial cross-sectional view illustrating internal
components of the example power tool 900.
[0146] The example power tool 900 shown in FIGs. 3A and 3B includes a motor assembly 910
and a ring gear mount 930 that are physically configured to provide for a reduced
overall length and/or girth of the power tool 900 (for example, compared to an overall
length and/or girth of the example power tool 100 described above with respect to
FIGs. 1A-1E). Many features of the example power tool 900 are similar to features
of the example power tool 100 described above with respect to FIGs. 1A-1E and/or the
example power tools 200, 300, 400, 500, 600, 700, 800 described above with respect
to FIGs. 2A-8B. Thus, duplicative detailed description thereof will not be repeated
except as necessary.
[0147] In the example shown in FIG. 9, the motor assembly 010 includes a solid core rotor
configuration, including embedded magnets. In the example motor assembly 910 shown
in FIG. 9, the solid core rotor configuration including the embedded magnets does
not form an annular recess in which the front motor bearing and/or the rear motor
bearing and/or the cam carrier bearing can be accommodated. Rather, the example motor
assembly 910 includes a ring gear mount 930 configured such that a front motor bearing
can be radially aligned with a cam carrier bearing, and for both the front motor bearing
and the cam carrier bearing to be substantially radially aligned with corresponding
end portion(s) of stator windings of the motor assembly 910. In this example arrangement,
the cam carrier may index, or set a location for, or may support a position of the
front motor bearing. The configuration of the ring gear mount 930 allows for a reduced
overall length of the example power tool 900 (for example compared to the overall
length of the example power tool 100 described above with respect to FIGs. 1A-1E)
and/or an overall length that is less than or equal to the overall length of the example
power tools 200, 300, 400, 500, 600, 700, 800 shown in FIGs. 2A-8B.
[0148] In some examples, the motor assembly 910 includes a rotor 904 including magnets 906
mounted in magnet pockets 907 formed in a rotor core 908. The example motor assembly
910 has an internal permanent magnet configuration in which the rotor magnets 906
are mounted in the magnet pockets 907 defined in the rotor core 908, such that the
rotor magnets 906 are embedded in the rotor core 908. The rotor core 908 is mounted
on the rotor shaft 902. A stator assembly 911 is positioned around the rotor 904.
The stator assembly 911 includes a stator core 912 having a series of teeth projecting
radially inward from the stator core 912, and a series of conductive windings 913
wound around the stator teeth.
[0149] The example ring gear mount 930 includes a cylindrical or rim-shaped portion 933,
and a radial portion 934 extending radially outward from the rim-shaped portion 933
of the ring gear mount 930. The ring gear mount 930 includes an outer rim portion
or a lip 931 projecting axially forward from the radial portion 934, for coupling
with a corresponding portion of the housing 190, and for receiving and supporting
a component of the transmission assembly 120, such as the ring gear 123. The rim-shaped
portion 933 (for example, together with corresponding portions of the rear carrier
plate 126A and the rearward projection 127 of the carrier 126) defines a bearing pocket
932 in which a cam carrier bearing 954 is received.
[0150] A front motor bearing 956 is mounted on a pinion 990 which is in turn mounted on
the rotor shaft 902, and is piloted, or set in position, or supported by, by the rearward
projection 127 of the rear carrier plate 126A of the carrier 126. In this example
arrangement, the rearward projection 127 is fitted between the front motor bearing
956 and the cam carrier bearing 954. Thus, in this example arrangement, an outer race
of the cam carrier bearing 954 is supported by the (stationary) ring gear mount 930,
with an inner race being supported by and rotating with the rearward projection 127
of the carrier 126. The front motor bearing 356 is supported by the rearward projection
127, that rotates with the carrier 126. That is, in this example, the outer race of
the front motor bearing 356 rotates together with the carrier 126, at a somewhat lower
speed than the inner race of the front motor bearing 956 that rotates together with
the rotor shaft 902, via the coupling of the pinion 990 to the rotor shaft 902.
[0151] In the example arrangement shown in FIG. 9, the front motor bearing 956 is in an
axially rearward position, such that the front motor bearing 956 is substantially
radially aligned with the cam carrier bearing 954, and substantially radially aligned
with the conductive windings 913, and the front motor bearing 956 and the cam carrier
bearing 954 are at least partially received within a motor envelope 980 of the motor
assembly 910. The motor envelope 980 may have a length L9 from a rear plane to a front
plane and a diameter D9 of a cylindrical boundary. In some examples, at least a portion
of the front motor bearing 956 and at least a portion of the cam carrier bearing 954
are received within the motor envelope 980.
[0152] In some examples, a fan, such as the fan 850 described above with respect to FIGs.
8A and 8B, may be coupled to the rotor 904, so as to rotate together with the rotor
904. The fan 850 and/or the rotor 904 may include geometry that provides for interlocking
of the fan 850 and the rotor 904, such that the fan 850 rotates together with the
rotor 904. In some examples, a rear motor bearing 958 is seated on a rear end portion
of the rotor shaft 902, within the recessed portion 857 of the fan 850, and axially
supported by the tool cap 198 coupled to the rear end portion of the tool housing
190.
[0153] The plurality of protrusions 853 provided on the second side of the fan plate 852
may be positioned to correspond to positions of the magnet pockets 907 of the rotor
904 when the rotor 904 and the fan 850 are coupled. In some examples, a shape, or
a contour, of each of the plurality of protrusions 853 may correspond to a shape,
or a contour, of a corresponding magnet pocket 907 in which the protrusion 853 is
to be received. Corresponding portions of the rotor core 908 extend beyond, or overhang,
a position of the magnets 906 received in the magnet pockets 907. That is, an axial
length of the magnet pockets 907 may be greater than an axial length of the corresponding
magnets 906 received therein, so that the protrusions 853 may be inserted into axial
end portions of the corresponding magnet pockets 907 not occupied by the magnets 906
received therein. Thus, the plurality of protrusions 853 may define geometric interlocking
features that, together with the corresponding magnet pockets 907, provide for interlocking
and coupling of the rotor 904 and the fan 850, such that the fan 850 rotates together
with the rotor 904.
[0154] In the example power tool 900, the front motor bearing 956 and the cam carrier bearing
954 are substantially radially aligned, and at least partially received within the
motor envelope 980. In some examples, the length L9 associated with the motor assembly
910 of the example power tool 900 may be less than or equal to the length L2 associated
with the motor assembly 210 shown in FIGs. 2A and 2B and/or the length L3 associated
with the motor assembly 310 shown in FIGs. 3A and 3B and/or the length L4 associated
with the motor assembly 410 shown in FIGs. 4A and 4B and/or the length L5 associated
with the motor assembly 510 shown in FIGs. 5A and 5B and/or the length L6 associated
with the motor assembly 610 shown in FIGs. 6A and 6B and/or the length L7 associated
with the motor assembly 710 shown in FIGs. 7A and 7B and/or the length L8 associated
with the motor assembly 810 shown in FIGs. 8A and 8B. In some examples, the diameter
D9 associated with the motor assembly 910 of the example power tool 900 may be less
than or equal to the diameter D2 associated with the motor assembly 210 shown in FIGs.
2A and 2B and/or the diameter D3 associated with the motor assembly 310 shown in FIGs.
3A and 3B and/or the diameter D4 associated with the motor assembly 410 shown in FIGs.
4A and 4B and/or the diameter D5 associated with the motor assembly 510 shown in FIGs.
5A and 5B and/or the diameter D6 associated with the motor assembly 610 shown in FIGs.
6A and 6B and/or the diameter D7 associated with the motor assembly 710 shown in FIGs.
7A and 7B and/or the diameter D8 associated with the motor assembly 810 shown in FIGs.
8A and 8B.
[0155] In some implementations, the length L9 of the example motor assembly 910 may be between
approximately 16.5 mm and 20.1 mm. In some examples, the length L9 may be smaller
than or equal to approximately 18.3 mm. In some implementations, the diameter D9 of
the example power tool 900 may be between approximately 45.9 mm and 56.1 mm. In some
examples, the diameter D9 may be smaller than or equal to approximately 51.0 mm. In
some implementations, an overall axial length of the example power tool 900 may be
between approximately 89.6 mm and 109.0 mm. In some examples, the overall axial length
of the example power tool 900 may be smaller than or equal to approximately 99.5 mm.
In some implementations, an overall girth of the example power tool 900 may be between
approximately 59.4 mm and 72.6 mm. In some examples, the overall girth of the example
power tool 900 may be smaller than or equal to approximately 66.0 mm. In some implementations,
an axial length from a front end portion of the motor assembly 910 (i.e., frontmost
part of the conductive windings 913) to a rear end portion of the carrier 126 i.e.,
rearmost part of the rear carrier plate 126A) is between approximately 3.2 mm and
5.2 mm. In some examples, the axial length from the front end portion of the motor
assembly 910 to the rear end portion of the carrier 126 is smaller than or equal to
approximately 4.8 mm, preferably smaller than or equal to approximately 4.4 mm, more
preferably smaller than or equal to approximately 4.0 mm. In some implementations,
an axial length from a rear end portion of the motor assembly 910 to a front end portion
of the tool holder 170 is between approximately 84.9 mm and 103.8 mm. In some examples,
the axial length from the rear end portion of the motor assembly 910 to the front
end portion of the tool holder 170 is smaller than or equal to approximately 93.4
mm. In some implementations, an inner diameter of the ring gear mount 930 is between
approximately 18.9 mm and 23.1 mm. In some examples, the inner diameter of the ring
gear mount 930 is smaller than or equal to approximately 21.0 mm. In some implementations,
an outer diameter of the ring gear mount 930 is between approximately 46.8 mm and
57.2 mm. In some examples, the outer diameter of the ring gear mount 930 is smaller
than or equal to approximately 52.0 mm. In some examples, a maximum operating voltage
of the removeable power tool battery pack coupled to the power tool is in the range
of approximately 20V to 80V, and a nominal voltage of the battery pack is in the range
of 18V to 72V. In some examples, a maximum output power of the motor assembly 910
is between approximately 396.0 W and 484.0 W when using a 20V battery pack, with a
current drawn by the motor assembly 910 between approximately 22.0 amps and 27.0 amps.
In some examples, the output power of the motor assembly 910 is greater than or equal
to approximately 440 W when using a 20V max battery pack, with current drawn by the
motor assembly 910 being greater than or equal to approximately 24.5 amps. Thus, in
power tool 900, a ratio of the maximum power output of the motor assembly 910 to the
axial length from the front end portion of the motor assembly 910 to the rear end
portion of the carrier 126 is greater than or equal to approximately 91.8 W/mm, preferably
greater than or equal to approximately 96.2 W/mm, more preferably greater than or
equal to approximately 101 W/mm. In some implementations, an output torque of the
example power tool 900 is between approximately 1642.0 in-lbs and 2007 in-lbs when
using a 20V max battery pack. In some examples, the output torque of the example power
tool 900 is greater than or equal to approximately 1825 in-lbs when using a 20V max
battery pack. In some examples, the output torque of the example power tool 900 is
greater than or equal to 2400 in-lbs.
[0156] As noted above, in some examples, a power tool, in accordance with implementations
described herein, includes an impact mechanism, such as, for example, the impact mechanism
140 described above with respect to the example power tool 100 shown in FIGs. 1A-1E.
In some examples, a front end portion of the cam shaft includes a pilot tip that is
received in a pilot hole in the anvil, to rotationally support the front end of the
cam shaft. This arrangement may guide axial assembly of the front end portion of the
cam shaft relative to the anvil but may permit some amount of axial movement of the
cam shaft. In this type of arrangement, the cam carrier bearing may constrain some
axial movement of the cam carrier.
[0157] FIGs. 10A-10J present features of an example power tool 1000, in accordance with
implementations described herein. The example power tool 1000 incorporates features
into the cam carrier that provide for axial constraint of the cam carrier. The example
features may eliminate the need for a cam carrier bearing to provide for axial constraint
of the cam carrier. In some examples, the example features may eliminate the need
for a front motor bearing to provide for axial constraint.
[0158] FIG. 10A is a perspective cross-section view, and FIG. 10B is a side cross-section
view, illustrating internal components of the example power tool 1000. FIGs. 10C and
10D are partial cross-sectional views, and FIGs. 10E-10G are perspective views, of
components of an example impact mechanism 1400 of the example power tool 1000. FIGs.
10H-10J are perspective views of an example cam carrier 1300 of the example power
tool 1000.
[0159] The example power tool 1000 includes a motor assembly 1010 including a rotor 1004,
including magnets 1006, mounted on a rotor shaft 1002, and a stator core 1012 with
a series of conductive windings 1013, and may be similar to one or more of the motors
assemblies described above. A ring gear mount 1030 is coupled to a corresponding portion
of the tool housing 190, for receiving and supporting a component of the transmission
assembly 1020. As best shown in Fig. 10B, the ring gear mount 1030 includes a plurality
of rearward projections that extend into slots formed between the respective stator
teeth of the stator core 1012 to secure the ring gear mount 1030 to at least partially
restraint the movement of the stator core 1012 relative to the ring gear mount 1030.
It is noted that Fig 10A depicts a cross-sectional view of the power tool along a
plane that intersects the stator teeth, and Fig. 10B depicts a cross0sectional view
along a plane that intersects the rearward projections. A rear motor bearing 1058
is mounted at a rear end portion of the rotor shaft 1002, within a corresponding recess
formed in the rear tool cap 198. A fan 1050 is coupled so as to rotate together with
the rotor 1004, to direct cooling air axially during operation of the power tool 1000.
A transmission assembly 1020 is coupled between the rotor 1004 and a cam carrier 1300,
to transmit torque from the motor assembly 1010 to the cam carrier 1300. The transmission
assembly1020 includes a pinion coupled on the rotor shaft 1002, having a sun gear
1022 formed on an end portion thereof, and one or more planet gears 1024 in meshed
engagement with the sun gear 1022. The one or more planet gears 1024 are mounted in
the cam carrier 1300 on pins 1025 that allow for rotation of the planet gears 1024
in response to rotation of the sun gear 1022. This transmission arrangement may be
similar to one or more of the transmission arrangements described above.
[0160] In this example arrangement, the cam carrier 1300 includes a first, or rear carrier
plate 1320A and a second, or front carrier plate 1320B, that support the one or more
planet gears 1024, and may be similar to one or more of the cam carriers described
above. In other implementations the cam carrier may include only a single carrier
plate that supports the pins that support the planet gears. In response to the application
of power to the motor assembly 1010, the rotor shaft 1002 and the sun gear 1022 rotate,
causing the planet gears 1024 to orbit the sun gear 1022, and the cam carrier 1300
to rotate at a reduced speed relative to the rotational speed of the rotor shaft 1002.
[0161] The example power tool 1000 includes an impact mechanism 1400 including the cam shaft
1310, with a generally cylindrical hammer 1412 received over the cam shaft 1310. In
some examples, the hammer 1412 may selectively engage an output spindle 1160 of the
power tool 1000, based on a position of the hammer 1412 on the cam shaft 1310. The
hammer 1412 may be movably coupled on the cam shaft 1310, and may include lugs 1418
configured to engage corresponding projections extending radially from an anvil 1414
fixedly coupled on an output spindle 1160. A compression spring 1141 is received in
a cylindrical recess in the hammer 1412, abutting a forward face of the front carrier
plate 1320B. The spring 1141 biases the hammer 1412 toward the anvil 1414 so that
the lugs engage the corresponding projections formed on the anvil 1414. The impact
mechanism may be similar to one or more of the impact mechanisms described above.
[0162] In this example arrangement, an external annular groove 1335 is formed in a pilot
tip 1330 of the cam shaft 1310. A corresponding interior annular groove 1415 is formed
in a pilot hole 1416 of the anvil 1414. A plurality of ball bearings1440 are received
in an annular channel defined by the external annular groove 1335 and the interior
annular groove 1415. The plurality of ball bearings may provide for both rotational
support and axial support of the cam carrier 1300. In some examples, the anvil 1414
may include a radial opening 1419 to facilitate insertion of the ball bearings 1440
into the annular channel defined by the annular grooves 1415, 1335 during assembly.
In some examples, the radial opening 1419 may be closed (for example, after insertion
of the plurality of ball bearings 1440) by a closing device 1425 such as, for example,
lock spring, a set screw, a plug, or other such closing device.
[0163] In this example arrangement, the support provided by the plurality of ball bearings
1440 received in the annular channel defined by the annular grooves 1415, 1335 at
the front end portion of the cam shaft 1310 allows for elimination of a cam carrier
bearing and/or a front motor bearing that would otherwise be used to support a rear
portion of the cam carrier 1300 and/or a front end portion of the rotor shaft 1002.
This arrangement reduces the overall length and/or girth of the power tool.
[0164] As shown in FIGs. 10H-10J, in some examples, such a cam carrier bearing and/or a
front motor bearing may be replaced with rolling disks 1500 supported on a rear side
of the rear carrier plate 1320A. In particular, the rolling disks 1500 may be supported
on the rear carrier plate 1320A by the same pins 1025 on which the planet gears 1024
are mounted. In response to rotation of the rotor shaft 1002, the rolling disks 1500
may roll against the rotor shaft 1002 and/or a pinion that is press fit onto the rotor
shaft 1002. In response to rotation of the rotor shaft 1002, the rolling disks may
roll against an interior facing rim portion 1520 of a ring gear 1023 of the transmission
assembly 1020. The rolling action of the rolling disks 1500 may provide radial support
for the rotor shaft 1002 and the cam carrier 1300. In some examples, the rolling disks
1500 may roll against an inside rim of the ring gear mount 1030 to which the ring
gear 1023 is fixed. The rolling disks may have a thickness or axial length that is
substantially less than a thickness or axial length of a cam carrier bearing. In some
implementations, the rolling disks may have a thickness of between approximately 1.8
mm and 2.2 mm. In some examples, the rolling disks 1500 may have a thickness of approximately
2.0 mm. In some implementations, the rolling disks 1500 may have a diameter of between
approximately 11.7 mm and 14.3 mm. In some examples, the rolling disks 1500 may have
a diameter of approximately 13.0 mm. This arrangement may reduce an overall length
and/or an overall girth of the example power tool 1000.
[0165] In some implementations, a length L10 of a motor envelope associated with the motor
assembly 1010 of the example power tool 1000 may be between approximately 19.1 mm
and 23.3 mm. In some examples, the length L10 may be less than or equal to approximately
21.2 mm. In some implementations, a diameter D10 of the motor envelope associated
with the motor assembly 1010 of the example power tool 1000 may be between approximately
45.9 mm and 56.1 mm. In some examples, the diameter D10 may be less than or equal
to approximately 51.0 mm. In some implementations, an overall axial length of the
example power tool 1000 may be between approximately 88.7 mm and 108.4 mm. In some
examples, the overall axial length of the example power tool 1000 may be less than
or equal to approximately 98.5 mm. In some implementations, an overall girth of the
example power tool 1000 may be between approximately 59.4 mm and 72.6mm. In some examples,
the overall girth of the example power tool 1000 may be less than or equal to approximately
66.0 mm. In some implementations, an axial length from a front end portion of the
motor assembly 1010 (i.e., frontmost part of the conductive windings 1013) to a rear
end portion of the cam carrier 1300 (i.e., rearmost part of the rear carrier plate
1320A) is between approximately 3.0 mm and 5.0 mm. In some examples, the axial length
from the front end portion of the motor assembly 1010 to the rear end portion of the
cam carrier 1300 is smaller than or equal to approximately 4.5 mm, preferably smaller
than or equal to approximately 4.1 mm, more preferably smaller than or equal to approximately
3.7 mm. In some implementations, an axial length from a rear end portion of the motor
assembly 1010 to a front end portion of the tool holder 170 is between approximately
84.9 mm and 103.8 mm. In some examples, the axial length from the rear end portion
of the motor assembly 1010 to the front end portion of the tool holder 170 is less
than or equal to approximately 94.3 mm. In some implementations, an inner diameter
of the ring gear mount 1030 is between approximately 12.6 mm and 15.4 mm. In some
examples, the inner diameter of the ring gear mount 1030 is less than or equal to
approximately 14.0 mm. In some implementations, an outer diameter of the ring gear
mount 1030 is between approximately 46.4 mm and 56.7 mm. In some examples, the outer
diameter of the ring gear mount 1030 is less than or equal to approximately 51.5 mm.
In some examples, a maximum operating voltage of the removeable power tool battery
pack coupled to the power tool is in the range of approximately 20V to 80V, and a
nominal voltage of the battery pack is in the range of 18V to 72V. In some examples,
a maximum output power of the motor assembly 1010 is between approximately 606.0 W
and 737.0 W when using a 20V battery pack, with a current drawn by the motor assembly
1010 between approximately 31.3 amps and 38.3 amps. In some examples, the output power
of the motor assembly 1010 is greater than or equal to approximately 670 W when using
a 20V max battery pack, with current drawn by the motor assembly 1010 being greater
than or equal to approximately 34.8 amps. Thus, in power tool 1000, a ratio of the
maximum power output of the motor assembly 1010 to the axial length from the front
end portion of the motor assembly 1010 to the rear end portion of the cam carrier
1300 is greater than or equal to approximately 163 W/mm, preferably greater than or
equal to approximately 171 W/mm, more preferably greater than or equal to approximately
180 W/mm. In some implementations, an output torque of the example power tool 1000
is between approximately 2498 in-lbs and 3053 in-lbs when using a 20V max battery
pack. In some examples, the output torque of the example power tool 1000 is greater
than or equal to approximately 2775 in-lbs when using a 20V max battery pack. In some
examples, the output torque of the example power tool 1000 is greater than or equal
to 3650 in-lbs.
[0166] A number of embodiments have been described. Nevertheless, it will be understood
that various modifications may be made without departing from the spirit and scope
of the specification.
[0167] In addition, any logic flows depicted in the figures do not require the particular
order shown, or sequential order, to achieve desirable results. In addition, other
steps may be provided, or steps may be eliminated, from the described flows, and other
components may be added to, or removed from, the described systems. Accordingly, other
embodiments are within the scope of the following claims.
[0168] The terminology used herein is for the purpose of describing particular example embodiments
only and is not intended to be limiting. As used herein, the singular forms "a," "an,"
and "the" may be intended to include the plural forms as well, unless the context
clearly indicates otherwise. The terms "comprises," "comprising," "including," and
"having," are inclusive and therefore specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude the presence or
addition of one or more other features, integers, steps, operations, elements, components,
and/or groups thereof. The method steps, processes, and operations described herein
are not to be construed as necessarily requiring their performance in the particular
order discussed or illustrated, unless specifically identified as an order of performance.
It is also to be understood that additional or alternative steps may be employed.
[0169] When an element or layer is referred to as being "on," "engaged to," "connected to,"
or "coupled to" another element or layer, it may be directly on, engaged, connected
or coupled to the other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being "directly on," "directly
engaged to," "directly connected to," or "directly coupled to" another element or
layer, there may be no intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in a like fashion
(e.g., "between" versus "directly between," "adjacent" versus "directly adjacent,"
etc.). As used herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0170] Although the terms first, second, third, etc. may be used herein to describe various
elements, components, regions, layers and/or sections, these elements, components,
regions, layers and/or sections should not be limited by these terms. These terms
may be only used to distinguish one element, component, region, layer or section from
another region, layer or section. Terms such as "first," "second," and other numerical
terms when used herein do not imply a sequence or order unless clearly indicated by
the context. Thus, a first element, component, region, layer or section discussed
below could be termed a second element, component, region, layer or section without
departing from the teachings of the example embodiments.
[0171] Terms of degree such as "generally," "substantially," "approximately," and "about"
may be used herein when describing the relative positions, sizes, dimensions, or values
of various elements, components, regions, layers and/or sections. These terms mean
that such relative positions, sizes, dimensions, or values are within the defined
range or comparison (e.g., equal or close to equal) with sufficient precision as would
be understood by one of ordinary skill in the art in the context of the various elements,
components, regions, layers and/or sections being described.
[0172] While certain features of the described implementations have been illustrated as
described herein, many modifications, substitutions, changes and equivalents will
now occur to those skilled in the art. It is, therefore, to be understood that the
appended claims are intended to cover all such modifications and changes as fall within
the scope of the implementations. It should be understood that they have been presented
by way of example only, not limitation, and various changes in form and details may
be made. Any portion of the apparatus and/or methods described herein may be combined
in any combination, except mutually exclusive combinations. The implementations described
herein can include various combinations and/or sub-combinations of the functions,
components and/or features of the different implementations described.