BACKGROUND
[0001] The present invention relates to an electric power tool provided with a fuel cell.
[0002] An electric power tool disclosed in Unexamined Japanese Patent Application Publication
No.
2008-132551 is provided with a fuel cell, and is configured to provide electric power from the
fuel cell to an electric motor.
SUMMARY
[0003] While a fuel cell generates electric power by oxidizing a fuel such as hydrogen with
an oxidizing agent such as oxygen, reaction water is produced by oxidation reaction.
In the aforementioned electric power tool, however, particular measures concerning
a method of processing the reaction water (water, in the above-referenced Publication)
are not explicitly disclosed.
[0004] If the reaction water is directly discharged from the interior of an electric power
tool to the outside, a user and a work object such as a building material undesirably
get wet.
[0005] It is preferable that the present invention can provide an electric power tool which
can inhibit reaction water produced in a fuel cell from being directly discharged
from the electric power tool.
[0006] An electric power tool according to the present invention includes a tool portion,
a fuel cell, a power drive source, and a water-holding unit. The fuel cell generates
electric power by oxidation reaction between a fuel and an oxidizing agent. The power
drive source receives electric power to drive the tool portion. The water-holding
unit holds a reaction water produced in the fuel cell by the oxidation reaction.
[0007] In the electric power tool of the present invention configured as such, the reaction
water produced in the fuel cell is held in the water-holding unit. Thus, the reaction
water can be inhibited from being directly discharged from the electric power tool.
[0008] The water-holding unit can be configured in any manner in order to hold the reaction
water. For example, the water-holding unit may be configured to be detachably installed
in the electric power tool. In this case, for example, the electric power tool may
include a holder portion that detachably holds the water-holding unit. In the electric
power tool configured as such, the reaction water held in the water-holding unit can
be easily processed (disposed of), by detaching the water-holding unit from the electric
power tool. Or, the water-holding unit may be configured to be attachable to or detachable
from the fuel cell or a battery pack housing the fuel cell, or have other configurations.
[0009] In the present invention, the water-holding unit may include a drainage inlet to
which the reaction water flows in. The electric power tool may include a drainage
outlet from which the reaction water is discharged. In this case, the electric power
tool may include a positioner which positions the drainage inlet with respect to the
drainage outlet, so that the reaction water flows in from the drainage outlet to the
drainage inlet. In the electric power tool configured as such, the reaction water
can be reliably received in the water-holding unit.
[0010] A packing may be provided around at least one of the drainage outlet and the drainage
inlet. In this case, the positioner may be configured to position the drainage inlet
with respect to the drainage outlet along such a direction that the packing is inhibited
from being damaged. In the electric power tool configured as such, the packing can
be inhibited from being damaged, and further inhibit the reaction water from being
discharged from the electric power tool due to damage in the packing.
[0011] The drainage outlet may be provided in any section of the electric power tool. For
example, the drainage outlet may be provided in a section where the water-holding
unit is held.
[0012] Also, the electric power tool of the present invention may be provided with an operation
prohibiting unit that prohibits operation of the power drive source, when the drainage
inlet is not located at a position where the reaction water can flow in from the drainage
outlet to the drainage inlet. In the electric power tool configured as such, the electric
power tool does not operate when the drainage inlet is not located at a position where
the reaction water can flow in from the drainage outlet to the drainage inlet. Thus,
the reaction water can be inhibited from being discharged from the electric power
tool due to vibration, and so on, which occurs by the operation of the electric power
tool. A user and a work object can be inhibited from getting wet.
[0013] The operation prohibiting unit may be configured in any manner in order to prohibit
operation of the power drive source. For example, the operation prohibiting unit may
be configured to prohibit the operation of the power drive source by interrupting
a supply passage of electric power from the fuel cell to the power drive source. In
this case, since electric power is not supplied to the power drive source, the operation
of the power drive source can be reliably prohibited.
[0014] Also, the electric power tool of the present invention may include a reaction water
remover that removes the reaction water held in the water-holding unit from the water-holding
unit. In the electric power tool configured as such, the reaction water held in the
water-holding unit can be inhibited from being accumulated to fill up the water-holding
unit with the reaction water.
[0015] The reaction water remover may be configured in any manner in order to remove the
reaction water from the water-holding unit. For example, the reaction water remover
may include a reaction water outlet formed in the water-holding unit in order to discharge
the reaction water held in the water-holding unit out of the water-holding unit. In
this case, the reaction water can be removed from the water-holding unit via the reaction
water outlet. Or, if the electric power tool includes a fan that is driven by the
power drive source, the reaction water remover may be configured to pass at least
part of an air flow induced by the fan through an interior of the water-holding unit.
In this case, evaporation of the reaction water is facilitated by the air flow, so
that the reaction water can be removed from the water-holding unit. As a result, the
number of times of operation to remove the reaction water can be reduced.
[0016] Also, the electric power tool of the present invention may include a fuel tank that
stores a fuel to be supplied to the fuel cell. In this case, the fuel tank and the
water-holding unit may be integrally formed. If the fuel tank and the water-holding
unit are integrally formed, the reaction water accumulated in the water-holding unit
can be easily processed (disposed of). Also, the fuel tank can be easily replenished
with the fuel.
[0017] Also, the electric power tool of the present invention may be provided with a main
body portion that includes the tool portion and the power drive source. In this case,
the water-holding unit may be separately provided from the main body portion. In case
that the water-holding unit is separately provided from the main body portion, the
water-holding unit may be configured to be attachable to a user of the electric power
tool. If the water-holding unit is configured as such, the user can operate the electric
power tool with the water-holding unit being attached to the user.
[0018] Also in the present invention, the water-holding unit may include a drainage inlet
to which the reaction water flows in, and a back flow inhibiting unit that inhibits
the reaction water held in the water-holding unit from flowing backward from the drainage
inlet out of the water-holding unit. In the electric power tool configured as such,
the reaction water can be inhibited from directly being discharged from the electric
power tool due to a back flow of the reaction water from the drainage inlet.
[0019] In the present invention, the water-holding unit may include an absorber that absorbs
and holds the reaction water. In the electric power tool configured as such, the reaction
water can be inhibited from flowing backward out of the water-holding unit, regardless
of posture of the electric power tool, since the absorber absorbs and holds the reaction
water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The present invention will now be described by way of example with reference to the
accompanying drawings, in which:
FIG. 1 is a schematic diagram of an electric power tool according to a first embodiment
of the present invention;
FIG. 2 is a schematic diagram of a battery pack according to the first embodiment
of the present invention;
FIG. 3A is a view taken in a front-back direction of a water-holding tank according
to the first embodiment of the present invention in a state being detached from the
battery pack;
FIG. 3B is a view taken in the front-back direction of the water-holding tank according
to the first embodiment of the present invention in a state being attached to the
battery pack;
FIGS. 4A and 4B are explanatory views taken in a right-left direction of the water-holding
tank according to the first embodiment of the present invention in an attached state;
FIG. 5 is a block diagram showing an electrical configuration of the electric power
tool according to the first embodiment of the present invention;
FIGS. 6A and 6B are views taken in the front-back direction of a water-holding tank
according to a second embodiment of the present invention in an attached state;
FIGS. 7A and 7B are views taken in the right-left direction of a water-holding tank
according to a third embodiment of the present invention in an attached state;
FIG. 8A is a view schematically showing configurations of a battery pack and a water-holding
tank according to a fourth embodiment of the present invention;
FIG. 8B is a circuit diagram showing a schematic electrical configuration of an electric
power tool according to the fourth embodiment of the present invention;
FIG. 9 is a view schematically showing a configuration of a water-holding tank according
to a fifth embodiment of the present invention;
FIG. 10 is a view schematically showing a configuration of a water-holding tank according
to a sixth embodiment of the present invention;
FIG. 11 is a view schematically showing a configuration of a water-holding tank according
to a seventh embodiment of the present invention;
FIG. 12 is a view schematically showing a configuration of a water-holding tank according
to an eighth embodiment of the present invention;
FIG. 13 is a view schematically showing a configuration of a main body of an electric
power tool according to the eighth embodiment of the present invention;
FIG. 14A is a view taken in a front-back direction of a water-holding tank according
to a ninth embodiment of the present invention in a state being detached from a battery
pack;
FIG. 14B is a view taken in a right-left direction of the water-holding tank according
to the ninth embodiment of the present invention in a state being attached to the
battery pack;
FIG. 15 is a schematic diagram of an electric power tool according to a tenth embodiment
of the present invention; and
FIG. 16 is a schematic diagram of a battery pack according to an eleventh embodiment
of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The following embodiments are examples in which an electric power tool according
to the present invention is adapted to an electric power tool such as an electric
driver, an electric drill, and others. In the following embodiments, the same reference
numerals are given to components identical or similar in function, and the description
thereof may be simplified or omitted.
[First Embodiment]
[0022] As shown in FIG. 1, an electric power tool 1 according to the present first embodiment
includes a main body portion 5 and a handle portion 7. A main body of the electric
power tool 1 is formed by the main body portion 5 and the handle portion 7. The main
body portion 5 has a substantially cylindrical outer shape. An electric motor 3 that
rotates/drives a driver bit and a drill bit is housed in the main body portion 5.
The handle portion 7 is provided in the main body portion 5 in such a manner as to
protrude from the main body portion 5. Particularly, the electric power tool 1 is
formed into a pistol-like shape.
[0023] To a rotation shaft of the electric motor 3 are provided a chucking 3A that secures
the driver bit and a fan 3B that blows cooling air to the electric motor 3. When the
electric motor 3 rotates, the chucking 3A and the fan 3B are integrally rotated with
the rotation shaft of the electric motor 3.
[0024] The handle portion 7 is a gripper to be gripped by a user. The handle portion 7 is
provided with a tool switch (trigger) 9 for the user to activate the electric power
tool 1 (electric motor 3).
[0025] At an end of the handle portion 7, a battery pack 11 that supplies electric power
to the electric motor 3 is detachably installed. As schematically shown in FIG. 2,
the battery pack 11 includes a casing 11E. Inside the casing 11E, at least a fuel
cell (FC stack) 11A, a fuel tank 11B, a rechargeable battery 11C and a fuel pump 11D
are housed.
[0026] The fuel cell 11A generates electric power by oxidizing a fuel with an oxidizing
agent. The fuel cell 11A of the present first embodiment is not a fuel cell which
is supplied with a reformed fuel (hydrogen), but is a so-called direct methanol fuel
cell (DMFC) that is directly supplied with a liquid fuel (methanol) stored in the
fuel tank 11B. The rechargeable battery 11C is a chargeable and dischargeable chemical
battery or a capacitor.
[0027] The fuel stored in the fuel tank 11B is supplied by the fuel pump 11D to the fuel
cell 11A. The fuel pump 11D is driven by electric power supplied from the rechargeable
battery 11C.
[0028] Returning to FIG. 1, in a downward side of the battery pack 11, a water-holding tank
13 that retains reaction water produced in the fuel cell 11A is detachably fitted
to the battery pack 11 (more particularly, the casing 11E). A volume of the water-holding
tank 13 of the present first embodiment is adapted to a volume which can hold reaction
water produced when all the fuel stored in the fuel tank 11B is reacted.
[0029] Here, the downward side of the battery pack 11 indicates a lower side of the drawing
sheet when the electric power tool 1 is arranged as shown in FIG. 1. Hereinafter,
if not otherwise specified, an upper side of the drawing sheet when the electric power
tool 1 is arranged as shown in FIG. 1 is referred to as an upward side, and the lower
side of the drawing sheet is referred to as the downward side.
[0030] As shown in FIGS. 3A and 3B, the water-holding tank 13 includes a resin-made tank
portion 13B that retains the reaction water. The tank portion 13B is provided with
a drainage inlet 13A from which the reaction water flows in. A packing (O-ring) 13C
made of an elastic body such as rubber is fitted around the drainage inlet 13A.
[0031] In a section of the battery pack 11 (more particularly, the casing 11E) where the
water-holding tank 13 is held, that is, on the downward side of the battery pack 11,
a drainage outlet 11F is provided from which the reaction water is discharged. A packing
(O-ring) 11G made of an elastic body such as rubber is also fitted around the drainage
outlet 11F.
[0032] As shown in FIGS. 3A, 3B, 4A and 4B, positioning portions 11H, 11J, 13D and 13E that
position the drainage inlet 13A with respect to the drainage outlet 11F so that the
reaction water flows in from the drainage outlet 11F to the drainage inlet 13A are
respectively provided in either of the water-holding tank 13 or the battery pack 11
(more particularly, the casing 11E).
[0033] More particularly, the water-holding tank 13 is, as shown in FIGS. 4A and 4B, attached
to the battery pack 11 in such a manner as to move parallel to a direction orthogonal
to an up and down direction with respect to the battery pack 11 (hereinafter, the
direction is referred to as a front-back direction). When the water-holding tank 13
is attached to the battery pack 11, the positioning portion 13E provided in the water-holding
tank 13 comes into contact with the positioning portion 11J provided in the battery
pack 11, thereby positioning the water-holding tank 13 in the front-back direction
with respect to the battery pack 11, as shown in FIG. 4B.
[0034] As shown in FIG. 3A, the pair of positioning portions 11H provided in the battery
pack 11 are constituted by two wall surfaces of the casing 11E, spaced apart in a
direction orthogonal to the up and down direction and to the front-back direction
(hereinafter, the direction is referred to as a right and left direction). As shown
in FIG. 3B, when the water-holding tank 13 is attached to the battery pack 11, the
pair of positioning portions 13D provided in the water-holding tank 13 come into contact
with the pair of positioning portions 11H provided in the battery pack 11, thereby
positioning the water-holding tank 13 in the right and left direction with respect
to the battery pack 11.
[0035] As noted above, when the position of the water-holding tank 13 in the right and left
direction and in the front-back direction with respect to the battery pack 11 is determined,
the drainage outlet 11F of the battery pack 11 and the drainage inlet 13A of the water-holding
tank 13 coincide with each other, thereby allowing the reaction water to flow in from
the drainage outlet 11F to the drainage inlet 13A. The position of the water-holding
tank 13 in the up-down direction with respect to the battery pack 11 is determined
by contact of an upper surface side of the water-holding tank 13 to an undersurface
side of the battery pack 11 (more particularly, the casing 11E).
[0036] As shown in FIG. 3A, a pair of holder portions 11K which detachably hold the water-holding
tank 13 with respect to the battery pack 11 are provided on the undersurface side
of the battery pack 11. The pair of holder portions 11K respectively extend in the
front-back direction, and are formed into a shape protruding in a direction facing
to each other, in cross sections orthogonal to the front-back direction (i.e., a near
L or hook-like shape). The pair of holder portion 11K hold the water-holding tank
13 by engaging with a pair of hook portions 13F provided in the water-holding tank
13. The pair of hook portions 13F are respectively formed into a shape protruding
in a direction separating from each other along the right and left direction, in cross
sections orthogonal to the front-back direction.
[0037] As shown in FIG. 4A, an engaging body 13G, which engages with an engaging portion
11L provided in the battery pack 11, is provided in the water-holding tank 13.
[0038] The engaging portion 11L is configured by a concave portion which is dented upward
from the undersurface of the battery pack 11. The engaging body 13G is projectably
and retractably housed in a hole which extends downward from the upper surface of
the water-holding tank 13 facing the undersurface of the battery pack 11. The engaging
body 13G is pressed (biased) toward the battery pack 11 (upward) by an elastic body
such as a spring 13H housed in the water-holding tank 13.
[0039] Thus, a front end side of the engaging body 13G (a side facing the undersurface of
the battery pack 11) is normally in a state protruding from the upper surface of the
water-holding tank 13 by the elastic force of the spring 13H. When an operating portion
13J is displaced downward by a user, the engaging body 13G is integrally displaced
with the operating portion 13J. Thereby, the whole engaging body 13G is housed inside
the hole (water-holding tank 13).
[0040] On the side of the positioning portion 13E in the front end side of the engaging
body 13G, a tilted surface 13K is provided which is tilted in a direction opposite
to a direction in which the water-holding tank 13 is attached to the battery pack
11. Thus, if the water-holding tank 13 is displaced in parallel toward the positioning
portion 11J with the pair of hook portions 13F caught by the pair of holder portions
11K, the tilted surface 13K and the battery pack 11 (casing 11E) are brought into
contact. Thereby, a force that presses the engaging body 13G into the water-holding
tank 13 operates on the engaging body 13G.
[0041] When the water-holding tank 13 is displaced in parallel until the positioning portion
13E provided in the water-holding tank 13 and the positioning portion 11J provided
in the battery pack 11 are brought into contact, the front end of the engaging body
13G is fitted into the engaging portion 11L to engage the engaging body 13G with the
engaging portion 11L, as shown in FIG. 4B. As a result, the position of the water-holding
tank 13 with respect to the battery pack 11 is held/fixed.
[0042] As shown in FIG. 5, the electric power tool 1 includes a controller 20. Operation
of the electric motor 3 and the fuel pump 11D is controlled by the controller 20.
The controller 20 drives the electric motor 3 and the fuel pump 11D by electric power
supplied from the rechargeable battery 11C and the fuel cell 11A. The controller 20
itself operates by electric power supplied from the rechargeable battery 11C.
[0043] Particularly, when the tool switch 9 is turned ON by a user, the controller 20 first
supplies electric power to the fuel pump 11D and the electric motor 3 from the rechargeable
battery 11C to activate the fuel pump 11D and the electric motor 3, thereby supplying
the fuel in the fuel tank 11B to the fuel cell 11A to generate electric power in the
fuel cell 11A, and also rotate the electric motor 3.
[0044] When electric power from the fuel cell 11A is started to be supplied, the controller
20, depending on the remaining power of the rechargeable battery 11C and the electric
power required by the electric motor 3, supplies the power supplied from the fuel
cell 11A to at least one of the electric motor 3 and the rechargeable battery 11C.
[0045] When the tool switch 9 is turned OFF by a user, the controller 20 stops electric
power supply to the fuel pump 11D and to the electric motor 3.
[0046] In the electric power tool 1 of the present first embodiment configured as above,
the reaction water produced in the fuel cell 11A is held in the water-holding tank
13. Thus, the reaction water is inhibited from being discharged directly from the
electric power tool 1.
[0047] Also, in the electric power tool 1 of the present first embodiment, the water-holding
tank 13 is detachably attached to the battery pack 11. Thus, by removing the water-holding
tank 13 from the battery pack 11, the reaction water retained in the water-holding
tank 13 can be easily processed (disposed of).
[0048] Further, the electric power tool 1 of the present first embodiment includes the positioning
portions 11H, 11J, 13D and 13E which position the drainage inlet 13A with respect
to the drainage outlet 11F. Thus, upon attachment of the water-holding tank 13, the
position of drainage inlet 13A with respect to the drainage outlet 11F is determined
so that the drainage outlet 11F and the drainage inlet 13A coincide with one another,
and the reaction water flows in from the drainage outlet 11F to the drainage inlet
13A. Accordingly, in the electric power tool 1 of the present first embodiment, the
reaction water discharged from the drainage outlet 11F can be reliably received by
the water-holding tank 13.
[0049] Further, in the electric power tool 1 of the present first embodiment, the packings
13C and 11G are respectively fitted around the drainage inlet 13A and the drainage
outlet 11F. Thus, the reaction water can be inhibited from leaking outside the electric
power tool 1 from a joint surface between the drainage outlet 11F and the drainage
inlet 13A.
[0050] In the present first embodiment, the chucking 3A is an example of the tool portion
of the present invention. The electric motor 3 is an example of the power drive source
of the present invention. The water-holding tank 13 is an example of the water-holding
unit of the present invention.
[Second Embodiment]
[0051] The present second embodiment is a variation of the above-described first embodiment.
Particularly, in the first embodiment, the engaging body 13G is configured to be displaced
in the up and down direction. In the present second embodiment, as shown in FIGS.
6A and 6B, the pair of the hook portions 13F are replaced with the pair of engaging
bodies 13G, and the pair of engaging bodies 13G are configured to be displaceable
in the right and left direction. Thereby, the pair of engaging bodies 13G are projectable
and retractable with respect to the water-holding tank 13.
[0052] In the present second embodiment, the water-holding tank 13 is attached to and detached
from the battery pack 11 by displacing the water-holding tank 13 in the up and down
direction with respect to the battery pack 11. Thus, the tilted surfaces 13K of the
engaging bodies 13G are provided on the undersurface side of the battery pack 11 on
the front end sides of the engaging bodies 13G.
[0053] Also, in the present second embodiment, the water-holding tank 13 is attached to
and detached from the battery pack 11 by displacing the water-holding tank 13 in the
up and down direction with respect to the battery pack 11. Thus, upon attaching the
water-holding tank 13 to the battery pack 11, a force that may crush both the packings
13C and 11G acts on the packings 13C and 11G. It is difficult for a shear force to
act. Accordingly, at least one of the packings 13C and 11G can be inhibited from being
damaged upon attaching the water-holding tank 13 to the battery pack 11. Further,
the reaction water can be inhibited from being discharged from the electric power
tool 1, due to damage to at least one of the packings 13C and 11G.
[Third Embodiment]
[0054] The present third embodiment is a variation of the first embodiment. Particularly,
as shown in FIGS. 7A and 7B, the drainage inlet 13A is provided in the positioning
portion 13E on the side of the water-holding tank 13, and the drainage outlet 11F
is provided in the positioning portion 11J on the side of the battery pack 11. Further,
the packings 13C and 11G are fitted respectively around the drainage inlet 13A or
the drainage outlet 11F. Both the positioning portions 13E and 11J are tilted with
respect to a horizontal plane along the front-back direction.
[0055] With such configuration, even if the water-holding tank 13 is moved parallel in the
front-back direction and attached to the battery pack 11, it is difficult for a shear
force to act on both the packings 13C and 11G. Thus, upon attaching the water-holding
tank 13 to the battery pack 11, at least one of the packings 13C and 11G can be inhibited
from being damaged. That is, the reaction water can be inhibited from being discharged
from the electric power tool 1 due to damage to at least one of the packings 13C and
11G.
[0056] The present third embodiment is not limited to the configuration shown in FIGS. 7A
and 7B. It is only necessary for both the positioning portions 13E and 11J to be tilted
with respect to a plane along a direction in which the water-holding tank 13 is attached.
For example, if the water-holding tank 13 is attached to the battery pack 11 obliquely
from the front and downward of the battery pack 11, both the positioning portions
13E and 11J can be provided parallel to a plane along the up and down direction.
[Fourth Embodiment]
[0057] The present fourth embodiment is configured to prohibit operation of the electric
motor 3, when the drainage inlet 13A is not at a position where the reaction water
can flow in from the drainage outlet 11F to the drainage inlet 13A (hereinafter, this
position is referred to as an attachment complete position).
[0058] Particularly, as shown in FIG. 8A, in at least one of the positioning portions 11H
and 11J (in the positioning portion 11J, in the present fourth embodiment) of the
battery pack 11, a tank detection switch 21 is provided which is configured to be
a closed state when the water-holding tank 13 is positioned at the attachment complete
position, and to be an open state when the water-holding tank 13 is not positioned
at the attachment complete position.
[0059] As shown in FIG. 8B, in the electric power tool 1 of the present fourth embodiment,
the tank detection switch 21 is connected in series with the electric motor 3, together
with a tool switch 9, so as to be able to connect and interrupt a supply passage of
electric power from the fuel cell 11A and the rechargeable battery 11C to the electric
motor 3.
[0060] With such configuration, when the water-holding tank 13 is not positioned at the
attachment complete position, the tank detection switch 21 is in an open state. Regardless
of a state of the tool switch 9, electric power is not supplied to the electric motor
3. When the water-holding tank 13 is positioned at the attachment complete position,
the tank detection switch 21 is in a closed state. Depending on the state of the tool
switch 9, electric power is supplied to the electric motor 3. In other words, in the
present fourth embodiment, the tank detection switch 21 functions as an example of
the operation prohibiting unit of the present invention, which prohibits operation
of the electric motor 3 when the drainage inlet 13A is not at the attachment complete
position.
[0061] Accordingly, in the present fourth embodiment, when the drainage inlet 13A is not
at the attachment complete position, electric power is not supplied to the electric
motor 3. The electric motor 3 is reliably inhibited from being operated. Thus, the
reaction water can be inhibited from being discharged from the electric power tool
1 due to vibration, and so on, which occurs by the operation of the electric motor
3. A user and a work object can be inhibited from getting wet.
[0062] The operation prohibiting unit is not limited to the tank detection switch 21. For
example, the operation prohibiting unit may be configured to mechanically lock the
tool switch 9, so that the tool switch 9 cannot be operated when the drainage inlet
13A is not at the attachment complete position.
[Fifth Embodiment]
[0063] As shown in FIG. 9, in the present fifth embodiment, a back-flow inhibiting valve
13L that inhibits the reaction water retained in the tank portion 13B from flowing
backward out of the tank portion 13B from the drainage inlet 13A is provided in the
water-holding tank 13. The back-flow inhibiting valve 13L is an example of the back-flow
inhibiting unit of the present invention.
[0064] Particularly, the back-flow inhibiting valve 13L is installed in the water-holding
tank 13 in such a manner as to be able to be displaced between a position to close
the drainage inlet 13A (position shown by a chain double-dashed line in FIG. 9) and
a position to open the drainage inlet 13A (position shown by a solid line in FIG.
9) by gravity that acts on the back-flow inhibiting valve 13L.
[0065] More particularly, the plate-like back-flow inhibiting valve 13L is swingably installed
in the water-holding tank 13 at a position to open/close the drainage inlet 13A inside
the tank portion 13B. Therefore, when the drainage outlet 11F is positioned upward
of the drainage inlet 13A in a direction of gravitational force, the back-flow inhibiting
valve 13L swings downward in the direction of gravitational force by gravity that
acts on the back-flow inhibiting valve 13L, thereby to be displaced to a position
to open the drainage inlet 13A. When at least part of the drainage outlet 11F is not
positioned upward of the drainage inlet 13A in the direction of gravitational force,
due to, for example, tilting of the electric power tool 1, the back-flow inhibiting
valve 13L swings downward in the direction of gravitational force by the gravity that
acts on the back-flow inhibiting valve 13L, thereby to be displaced to a position
to close the drainage inlet 13A.
[0066] Accordingly, when the drainage outlet 11F is positioned upward of the drainage inlet
13A in the direction of gravitational force, the reaction water discharged from the
drainage outlet 11F moves downward by the gravity. Thus, the reaction water retained
in the tank portion 13B is inhibited from flowing backward out of the tank portion
13B from the drainage inlet 13A.
[0067] When at least part of the drainage outlet 11F is not positioned upward of the drainage
inlet 13A in the direction of gravitational force, the drainage inlet 13A is closed
by the back-flow inhibiting valve 13L. Thus, the reaction water retained in the tank
portion 13B is inhibited from flowing backward out of the tank portion 13B from the
drainage inlet 13A.
[0068] As described in the above, in the present fifth embodiment, regardless of posture
of the electric power tool 1, the reaction water retained in the tank portion 13B
can be inhibited from flowing backward out of the tank portion 13B from the drainage
inlet 13A. The reaction water can be inhibited from being directly discharged from
the electric power tool 1.
[0069] In the present fifth embodiment, in order that the drainage inlet 13A is closed by
the back-flow inhibiting valve 13L even when the water-holding tank 13 is rotated
either to the right (clockwise) or to the left (counterclockwise) with respect to
the drawing sheet, the back-flow inhibiting valve 13L is installed in the water-holding
tank 13 so as to be tilted with respect to a vertical direction (up and down direction),
in the state shown in FIG. 9.
[Sixth Embodiment]
[0070] As shown in FIG. 10, in the present sixth embodiment, an absorber 13M which absorbs
and holds the reaction water is arranged inside the tank portion 13B. As the absorber
13M, for example, a sponge-like porous body may be used.
[0071] With such configuration, in the present sixth embodiment, the reaction water retained
in the tank portion 13B is absorbed and held by the absorber 13M. Regardless of the
posture of the electric power tool 1, the reaction water retained in the tank portion
13B can be inhibited from flowing backward out of the tank portion 13B from the drainage
inlet 13A. The reaction water can be also inhibited from being fluctuated, depending
on the posture of the electric power tool 1.
[Seventh Embodiment]
[0072] In the above-described first to sixth embodiments, the water-holding tank 13 is detachably
installed in the battery pack 11. Thus, upon discharging the reaction water retained
in the tank portion 13B, the water-holding tank 13 is removed from the battery pack
11 to discharge the reaction water from the drainage inlet 13A. To the contrary to
these embodiments, in the present seventh embodiment, a pair of drainage openings
13N which discharge the reaction water retained in the tank portion 13B are provided
downward side of the water-holding tank 13, as shown in FIG. 11. Further, the pair
of drainage openings 13N are sealed with a pair of caps 13P attachable to and detachable
from the pair of drainage openings 13N.
[0073] With such configuration, in the electric power tool 1 according to the present seventh
embodiment, the reaction water retained in the tank portion 13B can be discharged
by removing the caps 13P without removing the water-holding tank 13 from the battery
pack 11. Thereby, the reaction water held in the water-holding tank 13 can be inhibited
from being accumulated to fill up the water-holding tank 13.
[0074] The drainage openings 13N correspond to an example of the reaction water remover
and the reaction water outlet of the present invention.
[Eighth Embodiment]
[0075] In the present eighth embodiment, as shown in FIG. 12, the water-holding tank 13
and the battery pack 11 are integrated. Further, the water-holding tank 13 is configured
such that at least part of the air flow induced by the fan 3B is introduced into the
water-holding tank 13 (tank portion 13B) and evaporation of the reaction water retained
in the tank portion 13B is promoted.
[0076] Particularly, as shown in FIG. 13, a wind guide path 7A that guides part of the air
flow induced by the fan 3B (hereinafter, this part of the air flow is referred to
as a guide wind) into the water-holding tank 13 (tank portion 13B) is provided in
the main body of the electric power tool 1 (i.e., the main body portion 5 and the
handle portion 7). In the water-holding tank 13 integrated with the battery pack 11,
as shown in FIG. 12, an air inlet 13Q which communicates the wind guide path 7A and
the inside of the tank portion 13B, and an air outlet 13R which discharges the guide
wind guided into the inside of the tank portion 13B out of the water-holding tank
13, are provided.
[0077] In the electric power tool 1 according to the present eighth embodiment configured
as such, when the tool switch 9 is turned ON and the electric motor 3 is started to
rotate, the guide wind passes through the inside the tank portion 13B. Thus, evaporation
of the reaction water discharged from the fuel cell 11A (battery pack 11) and retained
in the tank portion 13B is promoted. The evaporated reaction water is discharged out
of the water-holding tank 13 from the air outlet 13R together with the guide wind.
[0078] Accordingly, in the electric power tool 1 according to the present eighth embodiment,
too much of the reaction water can be inhibited from being retained in the tank portion
13B (the water-holding tank 13). The number of operation of discharging the reaction
water can be reduced. The wind guide path 7A, the air inlet 13Q and the air outlet
13R correspond to an example of the reaction water remover of the present invention.
[0079] In FIG. 13, part of the air flow induced by the fan 3B is guided into the water-holding
tank 13 as the guide wind. The present invention is not limited to the above configuration.
For example, the electric power tool 1 may be configured such that the fan 3B is arranged
on the side of the chucking 3A, and all the air flow induced by the fan 3B is guided
into the water-holding tank 13 as the guide wind.
[0080] Also, in FIG. 12, the absorber 13M is arranged inside the tank portion 13B. The absorber
13M may be removed.
[Ninth Embodiment]
[0081] In the first embodiment, the pair of holder portions 11K are formed into a hook-like
shape, and sections of the pair of holder portions 11K facing each other are open.
In the present ninth embodiment, as shown in FIG. 14A, the sections of the pair of
holder portions 11K facing each other are connected and closed. Inside the closed
section, the water-holding tank 13 is housed. In the electric power tool 1 according
to the present ninth embodiment as well, the water-holding tank 13 can be attached
to or detached from the battery pack 11 by displacing (sliding) the water-holding
tank 13 in parallel to the front-back direction, as shown in FIG. 14B.
[Tenth Embodiment]
[0082] In the above-described first to ninth embodiments, the water-holding tank 13 is provided
separate from the main body of the electric power tool 1. However, the water-holding
tank 13 is installed in the main body of the electric power tool 1 or in the battery
pack 11 attached to the main body, upon use. The water-holding tank 13 is used in
a state integrated with the main body. In the electric power tool 1 of the present
tenth embodiment, at least the water-holding tank 13 is provided in a separate body
14 that can be attached to a user (for example, attached to the back, the waist, the
arm, or the leg of a user), as shown in FIG. 15.
[0083] The separate body 14 in the present tenth embodiment is configured to be attached
to (secured to) the user by means of a belt 22. In the electric power tool 1 according
to the present tenth embodiment configured as such, the user can operate the electric
power tool 1 with the water-holding tank 13 being attached to the user.
[0084] In FIG. 15, only the water-holding tank 13 is provided in the separate body 14. The
present invention is not limited to this configuration. The separate body 14 may house
the water-holding tank 13 and the battery pack 11.
[Eleventh Embodiment]
[0085] In the battery pack 11 of the above-described first embodiment, the fuel cell 11A,
the fuel tank 11B, and the rechargeable battery 11C are integrated. The water-holding
tank 13 is detachably attached to the battery pack 11.
[0086] As compared to such the battery pack 11 of the first embodiment, in the battery pack
11 in the eleventh embodiment, the fuel cell 11A and the rechargeable battery 11C
are integrally provided inside the casing 11E, while the water-holding tank 13 and
the fuel tank 11B are integrally provided inside a casing 11S detachably attached
to the casing 11E, as shown in FIG. 16.
[0087] When the casing 11S is attached to the casing 11E, the drainage outlet 11F provided
in the casing 11E and the drainage inlet 13A provided in the casing 11S communicate
with each other. Also, the casing 11E and the casing 11S are respectively provided
with a fuel supply opening 11T or 13T for feeding the fuel inside the fuel tank 11B
into the fuel cell 11A. When the casing 11S is attached to the casing 11E, the fuel
supply openings 11T and 13T communicate with each other. The fuel inside the fuel
tank 11B is fed into the fuel cell 11A by the fuel pump 11D.
[0088] In the electric power tool 1 of the eleventh embodiment configured as such, when
the casing 11S is detached, the reaction water accumulated in the water-holding tank
13 can be easily processed (disposed of). Also, the fuel tank 11B can be easily replenished
with the fuel.
[Other Embodiments]
[0089] The embodiments of the present invention are described in the above. However, the
present invention is not limited to the above-described embodiments and can take various
forms within a scope not departing from the gist of the invention.
[0090] In the above-described first to eleventh embodiments, the present invention is applied
to a pistol-shaped electric power tool. Adaptation of the present invention is not
limited to such electric power tools. The present invention can be applied to gardening
tools such as a lawnmower, for example.
[0091] In the above-described first to eleventh embodiments, the direct methanol fuel cell
(DMFC) is adopted as the fuel cell 11A. The present invention is not limited to such
configuration. Any types of fuel cells can be adopted.
[0092] In the above-described first to eleventh embodiments, the fuel cell 11A and the rechargeable
battery 11C are housed in the same casing 11E. The present invention is not limited
to such configuration. For example, the rechargeable battery 11C may be housed in
the main body of the electric power tool 1.
[0093] In the above-described first to eleventh embodiments, the fuel cell 11A and the rechargeable
battery 11C are provided as power sources. If, for example, high-pressure hydrogen
is used as the fuel, the fuel pump 11D is no longer necessary. Thus, the rechargeable
battery 11C may be removed.
[0094] In the above-described fourth embodiment, the electric power tool 1 is configured
to prohibit the operation of the electric motor 3 when the drainage inlet 13A is not
at the attachment complete position. The electric power tool 1 may be configured to
prohibit the operation of the electric motor 3 when an amount of the reaction water
retained in the water-holding tank 13 exceeds a predetermined amount. In this case,
for example, a detecting unit which detects whether or not the amount of the reaction
water retained in the water-holding tank 13 exceeds a predetermined amount may be
provided in the electric power tool 1.
[0095] In the above-described first to eleventh embodiments, the drainage outlet 11F is
provided in the section of the battery pack 11 where the water-holding tank 13 is
held. The present invention is not limited to such configuration. For example, the
drainage outlet 11F may be provided in a different section other than the section
in the battery pack 11 where the water-holding tank 13 is held.
[0096] In the above-described first embodiment, the engaging portion 11L is provided in
the battery pack 11, and the engaging body 13G is provided in the water-holding tank
13. The engaging portion 11L may be provided in the water-holding tank 13, and the
engaging body 13G may be provided in the battery pack 11.
[0097] It is explicitly stated that all features disclosed in the description and/or the
claims are intended to be disclosed separately and independently from each other for
the purpose of original disclosure as well as for the purpose of restricting the claimed
invention independent of the composition of the features in the embodiments and/or
the claims. It is explicitly stated that all value ranges or indications of groups
of entities disclose every possible intermediate value or intermediate entity for
the purpose of original disclosure as well as for the purpose of restricting the claimed
invention, in particular as limits of value ranges.
1. An electric power tool (1) comprising:
a tool portion (3A);
a fuel cell (11A) that generates electric power by oxidation reaction between a fuel
and an oxidizing agent;
a power drive source (3) that receives electric power to drive the tool potion (3A);
and
a water-holding unit (13) that holds a reaction water produced in the fuel cell (11A)
by the oxidation reaction.
2. The electric power tool (1) according to claim 1, further comprising:
a holder portion (11K) that detachably holds the water-holding unit (13).
3. The electric power tool (1) according to claim 1 or 2, wherein
the water-holding unit (13) includes:
a drainage inlet (13A) to which the reaction water flows in, and
the electric power tool (1) includes:
a drainage outlet (11F) from which the reaction water is discharged; and
a positioner (11H, 11J, 13D, 13E) that positions the drainage inlet (13A) with respect
to the drainage outlet (11F), so that the reaction water flows in from the drainage
outlet (11F) to the drainage inlet (13A).
4. The electric power tool (1) according to claim 3, wherein
a packing (11G, 13C) is provided around at least one of the drainage outlet (11F)
and the drainage inlet (13A), and
the positioner (11H, 11J, 13D, 13E) is configured to position the drainage inlet (13A)
with respect to the drainage outlet (11F) along such a direction in which the packing
(11G, 13C) is inhibited from being damaged.
5. The electric power tool (1) according to claim 3 or 4, wherein
the drainage outlet (11F) is provided in a section where the water-holding unit (13)
is held.
6. The electric power tool (1) according to any one of claims 3 to 5, further comprising:
an operation prohibiting unit (21) that prohibits operation of the power drive source
(3), when the drainage inlet (13A) is not located at a position where the reaction
water can flow in from the drainage outlet (11F) to the drainage inlet (13A).
7. The electric power tool (1) according to claim 6, wherein
the operation prohibiting unit (21) is configured to prohibit the operation of the
power drive source (3) by interrupting a supply passage of electric power from the
fuel cell (11A) to the power drive source (3).
8. The electric power tool (1) according to any one of claims 1 to 7, further comprising:
a reaction water remover (7A, 13N, 13Q, 13R) that removes the reaction water held
in the water-holding unit (13) from the water-holding unit (13).
9. The electric power tool (1) according to claim 8, wherein
the reaction water remover (13N) includes a reaction water outlet (13N) formed in
the water-holding unit (13) in order to discharge the reaction water held in the water-holding
unit (13) out of the water-holding unit (13).
10. The electric power tool (1) according to claim 8, further comprising:
a fan (3B) that is driven by the power drive source (3),
wherein the reaction water remover (7A, 13Q, 13R) is configured to pass at least part
of an air flow induced by the fan (3B) through an interior of the water-holding unit
(13).
11. The electric power tool (1) according to any one of claims 1 to 10, further comprising:
a fuel tank (11B) that stores a fuel to be supplied to the fuel cell (11A),
wherein the fuel tank (11B) and the water-holding unit (13) are integrally formed.
12. The electric power tool (1) according to any one of claims 1 to 11, further comprising:
a main body portion (5) that includes the tool portion (3A) and the power drive source
(3),
wherein the water-holding unit (13) is separately provided from the main body portion
(5).
13. The electric power tool (1) according to claim 12, wherein
the water-holding unit (13) is configured to be attachable to a user of the electric
power tool (1).
14. The electric power tool (1) according to any one of claims 1 to 13, wherein
the water-holding unit (13) includes:
a drainage inlet (13A) to which the reaction water flows in, and
a back flow inhibiting unit (13L) that inhibits the reaction water held in the water-holding
unit (13) from flowing backward from the drainage inlet (13A) out of the water-holding
unit (13).
15. The electric power tool (1) according to any one of claims 1 to 14, wherein
the water-holding unit (13) includes an absorber (13M) that absorbs and holds the
reaction water.