BACKGROUND
[0001] Rotary operating elements that are operable also in axial direction, such as a rotary
pull/push button, are known in the art and are used in a wide variety of machinery,
such as mobile machines. Examples are agricultural or construction vehicles that may
comprise a respective rotary operating element.
[0002] Repeated use of such rotary operating element may result in increased wear and may
reduce the lifetime. In such harsh operating environment, debris may further enter
the control element, which can lead to a malfunction of the mechanical components
used therein. To avoid such problems, operating elements that employ optical means
for detecting an actuation are known. However, such optical detection may likewise
be degraded in such environment, for example by dust particles entering the operating
element. Further, the problems related to the mechanical actuation mechanism remain.
[0003] It is thus desirable to provide a compact but robust operating element that can be
used in a respective harsh environment. It is in particular desirable to enable a
secure operation that does not result in increased wear and in a reduced lifetime
of the operating element.
SUMMARY
[0004] Accordingly, there is a need to mitigate at least some of the drawbacks mentioned
above and to provide an improved rotary operating element. It is particularly desirable
to reduce wear experienced by such rotary operating element while at the same time
providing an intuitive operation thereof.
[0005] This need is met by the features of the independent claims. The dependent claims
describe embodiments of the invention.
[0006] According to an embodiment of the invention, a rotary operating element for controlling
a function of a machine, such as of a mobile machine, in particular of a vehicle,
is provided. The rotary operating element comprises a shaft, wherein the shaft is
rotatable to provide a rotary control function and wherein the shaft is actuable in
the axial direction of the shaft to provide an axial control function. The shaft has
a default position in the axial direction. The rotary operating element further comprises
a restoring assembly configured to apply a restoring force in the axial direction
to the shaft to return the shaft to the default position. The restoring assembly is
a magnetic restoring assembly that comprises a first component coupled to (in particular
mounted to) a housing of the rotary operating element and a second component provided
on the shaft. The first component and/or the second component comprises a magnet.
The first component and the second component are configured to interact magnetically
to generate the restoring force when the shaft is moved in axial direction out of
the default position.
[0007] By providing the rotary operating element (abbreviated herein as "operating element")
with a magnetic restoring assembly, the wear associated with a respective mechanical
restoring assembly may be avoided. Furthermore, since the shaft needs to be rotated
for implementing the rotary control function, wear generally occurs on the mechanical
components of the axial control function during such rotation. By employing such magnetic
restoring assembly, such wear can be avoided and the shaft may be rotated without
causing friction on the mechanical components as in a conventional restoring assembly.
Such benefits may in particular be experienced when the shaft is rotated while being
pushed or pulled in the axial direction.
[0008] The rotary operating element may in particular be a rotary button, such as a rotary
push and/or pull button. The default position may correspond to an equilibrium position
of the forces applied to the shaft by the magnetic restoring assembly. The first and
second components may in particular interact to maintain the shaft in the default
position. It is not precluded that further restoring forces act on the shaft; however,
it is preferred that only a magnetic restoring force provided by the magnetic restoring
assembly acts on the shaft in axial direction.
[0009] The shaft may be movable from the default position in two axial directions including
a pushing axial direction and a pulling axial direction. The magnetic restoring assembly
may be configured to generate the restoring force for movement of the shaft in both
axial directions. A magnetic restoring force may thus be applied both, when the shaft
is moved in the pushing direction and is moved in the pulling direction. The operating
element may provide a respective pulling control function and pushing control function,
such as switching a particular device or tool on and off, moving a tool up or down,
or moving a tool left or right, and the like. In other embodiments, the shaft may
be movable only in one axial direction.
[0010] In an embodiment, the magnetic restoring assembly is configured to provide a contactless
interaction between the first component and the second component to apply the restoring
force to the shaft. Wear may thus be reduced, and debris entering the rotary operating
element may only have a limited effect on the functionality of the magnetic restoring
assembly. For example, in the default position, a circumferential gap may be present
between the first component and the second components, so that they are not in physical
contact. The restoring assembly does accordingly not impede the rotation of the shaft
and shaft rotation may not result in increased wear.
[0011] The first component may have an annular shape that includes a through-hole. The shaft
may extend through the through-hole, wherein in the default position, a first contour
of a radially inwardly facing surface of the annular first component faces a second
contour of a radially outwardly facing surface of the second component provided on
the shaft. Such contours that face each other may facilitate the generation of magnetic
force between the first and second components. The contours may for example be rotationally
symmetric about the rotation axis. This may avoid forces in radial direction, and
may thus support contactless operation of the restoring assembly. The first component
may be arranged concentrically with the shaft that includes the second component.
[0012] The first contour and the second contour may be shaped to define the default position.
The default position may thus not be mechanically fixed, such as by a latching mechanism
or the like, but may be defined by the magnetic interaction.
[0013] The magnetic restoring assembly may be configured to generate a predefined force
profile for the restoring force acting on the shaft at different axial positions of
the shaft. A desired force characteristic for the actuation of the rotary operating
element may thus be obtained.
[0014] For example, the first contour and the second contour may be shaped to generate a
predefined force profile for the restoring force acting on the shaft at different
axial positions of the shaft.
[0015] The magnetic restoring assembly may be configured to generate a force profile for
the restoring force that has a maximum at an axial position of the shaft that is located
between the default position and an axial position of the shaft at an end stop, e.g.
in push and/or pull direction.
[0016] For example, the first contour and the second contour may be shaped to generate a
force profile for the restoring force that has a maximum at an axial position of the
shaft that is located between the default position and an axial end stop of the shaft.
When the user actuates the operating element in axial direction, the user will thus
experience an increased force that has to be overcome before reaching, e.g., a position
of the shaft at which the respective control function is triggered. A pressure point
may thus be generated in the force profile that provides haptic feedback to the user.
In particular, by overcoming such pressure point when pushing or pulling the operating
element, the user will know precisely whether or not he has actuated the function
he/she intends to control.
[0017] The force profile may be shaped such that if the shaft is moved past the position
at which the restoring force has a maximum, the restoring force drops again. The user
thus obtains a clear indication that the maximum, i.e. the pressure point, has been
passed.
[0018] In a particular implementation, the shaft may be actuable from the default position
into a pushing axial direction to provide a push control function and into a pulling
axial direction to provide a pull control function. The first contour and the second
contour may be shaped such that the force profile of the restoring force has a respective
maximum for both the push axial direction and the pull axial direction. Haptic feedback
may thus be provided for either direction of actuation. It is also conceivable to
provide plural (e.g. local) maxima in the force profile for one or for both axial
directions of actuation. The user may thus experience plural pressure points when
either pulling or pushing the shaft.
[0019] The restoring force at the first maximum may be similar to or may be different from
the restoring force at the second maximum. The restoring force at the second maximum
is preferably smaller than at the first maximum, so that the force required by the
user to overcome the pressure point in a pulling direction is smaller than the force
required for overcoming the pressure point in the pushing direction. This may improve
the haptic experience for the user as pushing is generally performed more effortless
than pulling.
[0020] It is also conceivable that the first contour and the second contour are shaped such
that the force profile comprises an axial position of the shaft at which the restoring
force changes sign to provide a locked position of the shaft that is different from
the default position. The force profile may in particular change sign twice, wherein
at the second intersection of the force profile with the zero force, a second stable
position may be generated at which the shaft will be locked when actuated to that
position. This may allow latching the shaft at a particular position to continuously
activate the respective control function, until the user brings back the shaft into
the default position. Such locked position may also be provided at an end stop of
the shaft in axial direction, which simplifies the force profile required for implementing
a locked position.
[0021] In an embodiment, the first component comprises one, two, or more protrusions extending
in radial direction towards the shaft and/or the second component comprises one, two,
or more protrusions extending in a radial direction away from the shaft. At least
in the default position of the shaft, at least one of the protrusions of the respective
component forms part of a magnetic path towards the respective other component. Such
protrusion may close a magnetic path or may form part of a magnetic circuit from the
magnet through the respective other component. Such configuration may allow the generation
of relatively high restoring forces and may further provide an improved definition
of the default position. If two or more protrusions are provided on the same component,
they may be spaced apart in axial direction. A protrusion may be continuous in circumferential
direction, i.e. it may be a ring-shaped protrusion, or it may be provided as one or
more sections in circumferential direction. A ring-shaped or rotationally symmetric
protrusion may provide symmetrical forces that facilitate centering the shaft in radial
direction in the restoring assembly.
[0022] The first contour may for example be defined by the one, two or more protrusions
of the first component. The second contour may be defined by the one, two, or more
protrusions of the second component. Preferably, in the default position of the shaft,
at least one or two of the protrusions on the first component are arranged radially
opposite to at least one or two of the protrusions on the second component, respectively,
they may in particular face each other. By such arrangement of the protrusions, a
defined alignment and a high holding force may be achieved in the default position.
[0023] At least two of the protrusions on the first component and/or at least two of the
protrusions on the second component may have a different extension in axial direction
configured to generate an asymmetric force profile of the restoring force. By such
configuration, the haptic feedback experienced by the user may be adjusted in an efficient
manner. Such configuration may in particular allow the generation of different maxima
of the force profile for different axial directions of movement of the shaft. If the
second component is for example provided with a protrusion closer to a knob/handle
of the shaft and a protrusion further away from the knob/handle of the shaft, the
axial extension of the latter protrusion may be made larger to reduce the maximum
pulling force in the force profile. Preferably, at least two protrusions on the second
component are provided with different axial extensions, which may simplify the mechanical
configuration.
[0024] At least one protrusion on the first component may have a different axial extension
than a protrusion on the second component that it faces in the default position. The
change in restoring force with axial movement of the shaft may be made less steep
(for the contribution of these facing protrusions) which allows tuning of the force
profile and also reduction of the maximum restoring force for the respective axial
direction.
[0025] In an embodiment, the number of protrusions of the second component may be different
from the number of protrusions of the first component to achieve a predefined force
profile of the restoring force. Such additional protrusions may allow modulating the
force profile in the desired way. Interaction of an additional protrusion on the shaft
with a protrusion of the first component may for example generate additional force
after the shaft has been moved for a predefined distance in axial direction. More
protrusions may for example be provided by the second component than by the first
component.
[0026] In a particular implementation, the first component may comprise one, two, or more
return rings that are arranged concentrically with the rotational axis. The shaft
including the second component may be arranged radially inwardly of the one, two,
or more return rings, wherein the one, two, or more return rings may form part of
a magnetic path towards the second component. Such rings may provide a simple mechanical
implementation that closes a magnetic circuit via the second component. Each return
ring may form a respective protrusion at its radially inner edge, i.e. the above-mentioned
ring-shaped protrusion. The inner radial surface of each return ring may face a respective
ring-shaped protrusion of the second component when the shaft in the default position.
[0027] The first component may for example comprise a ring magnet, which may be concentric
with the shaft. Such ring magnet may be arranged between two of the return rings (and
concentrically therewith). Each return ring for example protrudes radially inwardly
from the ring magnet and may thus form a respective ring-shaped protrusion.
[0028] The first component may for example comprise one, two, or more magnets, e.g. ring
magnets. The first component may comprise one, two, three, or more return rings. The
one, two, or more magnets may be arranged between respective two, three, or more return
rings. Between two return rings, one, two, or more magnets may for example be arranged
(in axial direction). If three or more return rings are provided, one, two, or more
magnets may for example be stacked between at least one pair or between each pair
of return rings.
[0029] The second component may similarly comprise one, two, or more magnets.
[0030] The magnet may be a permanent magnet or may be an electromagnet. A magnet may be
provided in one of the first and second components, or in each of these components.
One component may be provided with a permanent magnet, and the other with an electromagnet,
or both with the same type of magnet. The first component may for example comprise
a respective winding of an electromagnet, which may be concentric with the shaft.
In other implementations, a winding may be provided on the second component, e.g.
around or within the shaft. Any combinations are conceivable.
[0031] The first and/or second component may also be provided with plural magnets of the
same type or of a different type.
[0032] In an embodiment, at least one of the first component and the second component comprises
an electromagnet, and the operating element further comprises a controller configured
to control the restoring force applied by the magnetic restoring assembly in dependence
on an axial position of the shaft. Control may for example be provided by controlling
a current through the electromagnet. The force profile may thus be determined by the
controller, alone or optionally in combination with the shape of the above-mentioned
contours. The force profile may thus also be adjusted dynamically, e.g. in dependence
on an operating mode of the control element. The controller may be configured to control
the restoring force in accordance with any of the force profiles disclosed herein
(e.g., a force profile having one or more pressure points and/or one or more locked
positions).
[0033] The second component may be mounted to the shaft or may be formed integrally with
the shaft. The second component and/or the return rings may comprise or consist of
soft iron. The rotary operating element may not have a mechanical return element for
the axial direction, i.e. the restoring force in axial direction may solely be supplied
by the magnetic return element.
[0034] The operating element may further comprise a bushing that supports the shaft. The
bushing may be configured to allow an axial movement and a rotational movement of
the shaft. The bushing may for example provide a glide bearing.
[0035] In an embodiment, the rotary operating element further comprises a magnetic sensor
configured to detect a rotation of the shaft and/or to detect an axial movement of
the shaft. Preferably, the detection occurs contactless. By providing a contactless
restoring force and providing a contactless detection, wear of the operating element
can further be reduced and the operating element is made particularly resistant to
debris and harsh environments. The electrical and mechanical configuration may further
be simplified by detecting both the axial actuation and the rotary actuation by the
same magnetic sensor.
[0036] The operating element may further comprise a permanent magnet element mounted to
the shaft, in particular to an axial end of the shaft that is opposite to the end
that is to be actuated by the user. The magnetic sensor may be mounted spaced apart
from the end of the shaft, in particular from the permanent magnet element. Rotation
of the shaft may for example lead to a rotating magnetic field which may be detected
by the magnetic sensor. Axial movement of the shaft may result in a different field
strength (due to the different distance) that is detected by the magnetic sensor.
The same magnetic sensor may thus detect both the rotation and the axial actuation
of the shaft by detecting changes to the magnetic field generated by the permanent
magnet element.
[0037] The sensor may for example be a Hall-sensor. The Hall-sensor may be provided on an
integrated circuit that is mounted on a circuit board of the rotary operating element.
The magnetic sensor, in particular the integrated circuit, may provide two or more
Hall-sensors, thus providing redundancy and fail-safe operation.
[0038] The rotary operating element may further include an axial stop for stopping a movement
of the shaft in axial direction, either in one or both directions if provided. Such
axial stop may be provided by a housing part and/or by a bushing supporting the shaft
and/or by the first component. The axial stop may for example include a protrusion
on the shaft that makes contact with the respective housing part or first component.
An axial stop is preferably provided in push direction and is arranged such that the
above-mentioned magnet element is spaced apart from the magnetic sensor when the axial
stop in push direction is engaged. A contactless operation of the magnetic sensor
may thus be ensured.
[0039] According to a further embodiment of the invention, a machine, in particular a mobile
machine, such as an agricultural, construction, or industrial vehicle is provided.
The machine comprises a rotary operating element having any of the configurations
disclosed herein for controlling a function of the machine. By such machine, advantages
similar to the ones outlined further above may be achieved.
[0040] According to a further embodiment of the invention, a method of operating a rotary
operating element for a controlling a function of a machine is provided. The operating
element may have any of the configurations described herein. The method comprises
moving the shaft of the operating element in axial direction out of the default position
and generating the restoring force by magnetic interaction between the first component
and the second component of the magnetic restoring assembly. By such method, a contactless
operation in axial direction may be achieved. Further, advantages similar to the ones
outline above with respect to the rotary operating element may be achieved by such
method.
[0041] It is to be understood that the features mentioned above and those yet to be explained
below can be used not only in the respective combinations indicated, but also in other
combinations or in isolation, without leaving the scope of the present invention.
In particular, the features of the different aspects and embodiments of the invention
can be combined with each other unless noted to the contrary.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The forgoing and other features and advantages of the invention will become further
apparent from the following detailed description read in conjunction with the accompanying
drawings. In the drawings, like reference numerals refer to like elements.
Fig. 1 is a schematic drawing showing a sectional side view of a rotary operating
element according to an embodiment.
Fig. 2 is a schematic drawing showing an enlarged section of the rotary operating
element of figure 1.
Fig. 3 is a schematic drawing showing an exemplary implementation of the magnetic
restoring assembly of figure 2.
Fig. 4 is a diagram showing a restoring force profile of the magnetic restoring assembly
of figure 3.
Fig. 5 is a schematic drawing showing an exemplary implementation of the magnetic
restoring assembly of figure 2.
Fig. 6 is a diagram showing a restoring force profile of the magnetic restoring assembly
of figure 5.
Fig. 7 is a schematic drawing showing an exemplary implementation of the magnetic
restoring assembly of figure 2.
Fig. 8 is a diagram showing a restoring force profile of the magnetic restoring assembly
of figure 7.
Fig. 9 is a schematic drawing showing an exemplary implementation of the magnetic
restoring assembly of figure 2.
Fig. 10 is a diagram showing a restoring force profile of the magnetic restoring assembly
of figure 9.
Fig. 11 is a schematic drawing showing an exemplary implementation of the magnetic
restoring assembly of figure 2.
Fig. 12 is a flow diagram illustrating a method of operating a rotary operating element
according to an embodiment.
DETAILED DESCRIPTION
[0043] In the following, embodiments of the invention will be described in detail with reference
to the accompanying drawings. It is to be understood that the following description
of the embodiments is given only for the purpose of illustration and is not to be
taken in a limiting sense. It should be noted that the drawings are to be regarded
as being schematic representations only, and elements in the drawings are not necessarily
to scale with each other. Rather, the representation of the various elements is chosen
such that their function and general purpose become apparent to a person skilled in
the art. As used herein, the singular forms "a," "an," and "the" are intended to include
the plural forms as well, unless the context clearly indicates otherwise. The terms
"comprising," "having," "including," and "containing" are to be construed as openended
terms (i.e., meaning "including, but not limited to,") unless otherwise noted.
[0044] Fig. 1 schematically illustrates a rotary operating element 10 implemented as a rotary
push and pull button. In other implementations, it may only be a rotary push button
or a rotary pull button. It comprises a knob or button 19 to be actuated by a user
that has a recess for receiving the rotary shaft 12. The user can push or pull knob
19 to actuate shaft 12 in axial direction to activate a respective axial control function
and can rotate the knob 19 to rotate shaft 12 about rotational axis 13 in order to
operate a rotary control function. A bushing 16 supports shaft 12 rotationally in
housing 11 such that it is actuable in axial direction, i.e. in a direction parallel
to the rotational axis 13. Bushing 16 provides a sliding bearing; however, other types
of rotational support may be provided.
[0045] Restoring assembly 15 returns the shaft to a default position, in particular an equilibrium
position, when the operating element 10 is not actuated (in axial direction). Assembly
15 is a magnetic restoring assembly that employs magnetic interaction to provide a
force in axial direction that returns the shaft to the default position, which is
illustrated in Fig. 1. The magnetic restoring assembly 15 will be described in more
detail further below.
[0046] A sensor assembly 17 detects both axial operation and rotational operation of the
operating element 10. Sensor assembly 17 includes a magnet element 51 mounted by the
magnet holder 53 to the shaft 12 and magnetic sensor 52. Magnet element 51 may be
magnetized in a direction perpendicular to rotational axis 13 (e.g., north pole on
the left side and a south pole on the right side in Fig. 1), or may include any other
configuration, such as a ring magnet having plural opposing poles distributed circumferentially,
so that two north poles and two south poles for example face the magnetic sensor 52.
Rotation of shaft 12 thus results in a rotating magnetic field that is sensed by magnetic
sensor 52 to detect rotary actuation. Movement of shaft 12 in axial direction results
in a different field strength being experienced by magnetic sensor 52, so that the
axial position of shaft 12 and thus a push or pull operation of operating element
10 can be detected. A reliable and contactless detection of the actuation of rotary
operating element 10 is thus achieved. Magnetic sensor 52 is provided on circuit board
54 that is mounted to housing 11. A Hall-sensor may for example be used. It should
be clear that the geometric configuration of the arrangement of magnetic element 51
and magnetic sensor 52 can be changed and can be adapted in accordance with the spatial
requirements.
[0047] Magnet element 51 is mounted to an end of shaft 12 that is opposite to the end to
which the knob 19 is mounted. Magnet element 51 is arranged rotationally symmetrically
about the rotation axis 13. Magnet element 51 faces and is spaced apart from the magnetic
sensor 52.
[0048] Fig. 2 is an enlarged section of the drawing of Fig. 1 that illustrates the restoring
assembly 15 in more detail. Restoring assembly 15 comprises a first component 20 that
is mounted to the housing 11 and a second component 30 that is provided on the shaft
12. Second component 30 is in the present example integral with shaft 12, but it may
also be or comprise a separate component that is mounted to shaft 12 or integrated
therein. A magnet 40 is provided in the first component 20 but may additionally or
alternatively be provided in second component 30. Both component 20 and component
30 are rotationally symmetric about the rotational axis 13 of shaft 12. Component
20 has a radially inwardly facing contour 21 that faces the radially outwardly facing
contour 31 of the second component 30. Contour 21 of component 20 comprises the protrusions
25 and 26 protruding radially inwardly, they are ring-shaped protrusions in the present
example. The contour 31 of the second component 30 comprises protrusions 35 and 36
that extend radially outwardly and similarly form ring-shaped protrusions. Protrusion
35 is shaped and arranged to face protrusion 25, and protrusion 36 is shaped and arranged
to face protrusion 26.
[0049] The protrusions 25, 26 and 35, 36, and in particular the parts providing these protrusions,
may be made of soft iron material. Magnet 40 may be a ring magnet that is magnetized
to have opposite magnetic poles at its respective opposite annular end faces.
[0050] It may for example present a north pole on the annular end face 40-1 and a south
pole on the annular end face 40-2, or vice versa. Protrusions 25, 26 may be provided
by annular return rings 27, 28 between which the magnet 40 is arranged. Via return
rings 27, 28 and their protrusions 25, 26, and via the second component 30 and its
protrusions 35, 36, a magnetic circuit is thus formed. The magnetic field lines will
concentrate in the return rings 27, 28 and a magnetic path is formed via the second
component 30 that closes the magnetic field lines. The magnetic field lines may in
particular concentrate in the soft iron material of the return rings 27, 28 and of
the second component 30.
[0051] Opening this magnetic circuit by either pulling or pushing the shaft 12 thus requires
the application of a force, and the restoring assembly 15 generates a respective restoring
force that acts to bring the shaft 12 back into the equilibrium position illustrated
in Fig. 2. The restoring assembly 15 can be adapted to generate a desired force profile
for the restoring force, which can be the same or can be different for the pulling
direction and the pushing direction of shaft 12. The force profile can be adapted
by adjusting properties of magnet 40, adapting the position where magnet 40 is placed,
adapting the shape of the contours 21, 31, adapting the material of the protrusions,
and the like. To increase the restoring force or further modulate the restoring force,
further magnetic restoring assemblies 15 may be provided on shaft 12.
[0052] A gap is present between the first component 20 and the second component 30, in particular
between the respective protrusions that face each other. The restoring force is thus
applied contactlessly to the shaft 12. Further, rotation of shaft 12 is not impeded
by the restoring assembly 15. Restoring assembly 15 thus provides no resistance to
the rotation and significantly reduces wear of the operating element 10, even when
used in harsh conditions.
[0053] Operating element 41 further comprises an axial stop 41 in push direction that is
contacted by a protrusion on shaft 12 to stop any further axial travel of the shaft.
Axial stop 41 is formed by bushing 16 in the present example. Further, an axial stop
42 in pull direction is provided by housing 11. A protrusion on shaft 12 contacts
axial stop 42 to prevent any further movement of shaft in pull direction. The protrusions
on the shaft are in the present example provided by the protrusions of the second
component 30, thus implementing two functionalities in component 30 and improving
the compactness of element 10. In other embodiments, axial stops 41, 42 may be provided
at another position and may be contacted by another part of the shaft.
[0054] Fig. 3 schematically illustrates the restoring assembly 15 of Fig. 2 wherein other
components of operating element 10 are not shown to simplify the presentation. Fig.
3 illustrates a situation in which the shaft 12 has been pulled (in positive Z-direction)
so that a restoring force acts towards the default position (in negative Z-direction).
Protrusions 25, 26 and 35, 36 are of a similar size (with respect to their extension
in axial direction) and are arranged so that they face each other in the default position.
For such symmetric configuration, the force profile for the restoring force F illustrated
in Fig. 4 is obtained. It can be seen that the restoring force F reaches a maximum
value at position 71, which corresponds to the position shown in Fig. 3 (the force
value is negative in Fig. 4 as it acts in negative Z-direction). When shaft 12 is
pushed, the restoring force F reaches a maximum at position 72. Due to the symmetric
configuration, the force at maxima 71, 72 has a similar magnitude. As the restoring
force becomes smaller again once the maximum value has been passed, the user will
experience a point of resistance (pressure point) when actuating the operating element
10 either in push or in pull direction. The maxima 71, 72 thus constitute pressure
points that provide haptic feedback to the user. This allows the user to safely recognize
when the respective function controlled by the control element is activated.
[0055] Fig. 5 illustrates a further exemplary implementation of the restoring assembly 15
of Fig. 2. To reduce the maximum value of the restoring force that has to be overcome
by the user when actuating the operating element 10 in the pull direction, the protrusion
36 of the second component 30 has been enlarged in axial direction. In the resulting
force profile of Fig. 6, it can be seen that the maximum restoring force 71 in pulling
direction is smaller (5 N) than the maximum restoring force 72 in pushing direction
(about 6.5 N) that has to be overcome by the user. This may improve the haptic feedback
for the user, since the subjective perception is generally such that a higher force
needs to be applied for pulling than for pushing even though both forces are the same.
The (absolute) force values at the maxima 71, 72 can thus be made different so that
the subjective perception of a similar pulling force and pushing force is obtained.
[0056] Fig. 7 illustrates a further possible implementation of the restoring assembly 15
of Fig. 2. For changing the restoring force profile, a further protrusion 39 is provided
on the second component 30. The resulting restoring force profile is shown in Fig.
8. Although the sizes of the protrusions 25, 26 and 35, 36 are similar (in particular
their axial extension), the maximum pulling force 71 that has to be overcome is further
reduced. The maximum restoring force 72 that has to be overcome when actuating shaft
12 in the pushing direction is of a similar value. Further, by means of the further
protrusion 39, a zero crossing 73 of the restoring force profile is obtained in the
pull-direction. The restoring force is thus reversed, so that the shaft will not by
itself return to the default position. A locked position is thereby generated in which
the shaft remains until the user pushes the shaft back towards the default position
(in particular to a position in which the restoring force acts again towards the default
position). Additionally or alternatively, a respective locked position may be provided
in the push-direction, e.g. by providing one or more respective protrusions. One or
more of such further protrusions 39 may additionally or alternatively be provided
on the first component 20, in particular if a magnet is provided on the second component
30.
[0057] A plurality of possibilities thus exists for adapting the contour 31 for changing
the restoring force profile. Additionally or alternatively, the contour 21 may be
adapted (e.g. in a similar manner) to adjust the restoring force profile.
[0058] In the example of Fig. 2, a further possibility of adapting the contours 21, 31 is
shown. In this example, the axial extension of protrusions 35 is larger than the axial
extension of protrusion 25, and the axial extension of protrusion 36 is smaller than
the axial extension of protrusion 26. A variety of ways thus exist for adjusting the
force profile.
[0059] Fig. 9 illustrates a further example, wherein not only the contours 21, 31 are adapted
to adjust the restoring force profile, but a second magnet 40 is provided in the second
component 30. The poles of both magnets 40 may be aligned such that the magnetic strength
is increased. This is illustrated in Fig. 10, where it can be seen that the maximum
restoring force 72 in the pushing direction is increased to almost 10 N. Due to the
asymmetric contours 21, 31, the maximum restoring force 71 in pull direction is maintained
below 7.5 N. Two pressure points that provide an improved haptic feedback may thus
be provided similar to the example of Figs. 5 and 6, but with an overall higher restoring
force.
[0060] In the above examples, the magnet 40 is implemented as a permanent magnet, but may
also be implemented as an electromagnet. Fig. 11 shows an example in which magnet
40 is implemented as an electromagnet 45. An electromagnet may be provided in the
first component 20 and/or in the second component 30. In the first component 20, either
magnet sections having windings around them may be distributed circumferentially about
the rotation axis 13 (as shown in figure 11), or windings of component 20 may extend
circumferentially about the shaft 12 (shaft 12 may then essentially be arranged inside
a coil formed by such windings of the first component 20). For the second component
30, such electromagnet 45 may for example comprise windings 44 that are wound about
the shaft 12, e.g. in a respective recess provided in the shaft or on the surface
of the shaft. Such electromagnet 45 provided in the first component 20 and/or in the
second component 30 may in a similar manner generate a magnetic field that applies
a restoring force to the shaft 12. As mentioned above, the restoring assembly 12 may
comprise an electromagnet in only one of the components 20, 30, or may combine an
electromagnet in one component with a permanent magnet in the other component. A combination
of an electromagnet and a permanent magnet in the same component is likewise possible.
[0061] Operating element 10 may comprise a controller 46 for controlling the electromagnet
45. A power source 47 may for example be controlled to apply a respective current
to the windings in order to control the magnetic field. Changes to the current, e.g.
due to changes in flux due to movement of the shaft, may be detected by current sensors
49 and may provide feedback for controller 46. Additionally or alternatively, a position
sensor 48 may employed that detects the axial position of shaft 12 for providing feedback
to controller 46. Controller 46 may thus control the restoring force profile in dependence
on the axial position of the shaft 12. The skilled person will recognize that this
allows the implementation of a variety of restoring force profiles, such as any of
the force profiles disclosed herein. Besides controlling the restoring force, the
controller 46 may additionally or alternatively provide impedance control, which may
control a mechanical impedance of the shaft in axial direction in dependence on the
axial position of the shaft (using, e.g., stiffness and damping as control variables).
An impedance profile may be employed and may define a mechanical target impedance,
and the magnetic restoring force generated by the electromagnet 45 may be controlled
in accordance with such target impedance. For example, feedback control may be employed
(e.g., position-based active impedance control) based on a position detected by position
sensor 48.
[0062] The position sensor 48 may be an additional sensor, or position measurements by Hall-sensor
52 may be used.
[0063] The above-described restoring force profiles have two pressure points, one for actuation
in pulling direction and one for actuation in pushing direction. The force profiles
may be modified to have any desired number of pressure points such as plural or no
pressure points in a certain direction of actuation. The restoring force profile may
also be adapted so that a locking position is generated, for example by reducing the
restoring force so that at a certain point, it changes sign, so that the shaft is
driven towards the end stop. Additional protrusions may for example be provided on
the second component 20 to generate the respective magnetic force. Additional lock
positions may be generated by providing additional protrusions.
[0064] The skilled person will readily appreciate that the above-described ways of modifying
the restoring force profile can be combined with each other to generate any desired
restoring force profile that is suitable for the particular application of rotary
operating element 10.
[0065] Fig. 12 is a flow diagram showing a method of operating a rotary operating element
having any of the configurations described herein. In step S 1, the rotary operating
element including the magnetic restoring assembly is provided. In step S2, the shaft
12 is moved in axial direction out of the default position. In step S3, the magnetic
restoring assembly 15 generates a restoring force that acts on the shaft towards the
default position. In step S4, the axial movement of the shaft is detected contactlessly
by the magnetic sensor 52. Besides the shaft being supported by the bushing 16, a
completely contactless operation of the operating element 10 may thus be achieved.
Some steps of the method are optional (such as step S4) and the steps may be performed
in a different order or simultaneously, such as steps S2, S3, and S4.
[0066] While specific embodiments are disclosed herein, various changes and modifications
can be made without departing from the scope of the invention. The present embodiments
are to be considered in all respects as illustrative and non-restrictive, and all
changes coming within the meaning and equivalency range of the appended claims are
intended to be embraced therein.
List of reference signs
[0067]
- 10
- rotary operating element
- 11
- housing
- 12
- shaft
- 13
- rotation axis
- 15
- restoring assembly
- 16
- bushing
- 17
- sensor assembly
- 18
- housing cover
- 19
- knob/button
- 20
- first component of restoring assembly
- 21
- contour of first component
- 25, 26
- protrusion
- 27, 28
- return ring
- 30
- second component of restoring assembly
- 31
- contour of second component
- 31
- contour of second component
- 35, 36
- protrusion
- 37, 38
- return ring
- 39
- protrusion
- 40
- magnet
- 40-1
- magnet annular end face
- 40-2
- magnet annular end face
- 41
- axial stop push direction
- 42
- axial stop pull direction
- 44
- windings
- 45
- electromagnet
- 46
- controller
- 47
- power source
- 48
- position sensor
- 49
- current sensor
- 51
- magnet element
- 52
- magnetic sensor
- 53
- magnet holder
- 54
- circuit board
- 71
- maximum restoring force in pull direction
- 72
- maximum restoring force in push direction
- 73
- zero crossing of restoring force
- S1-S4
- method steps
1. A rotary operating element for controlling a function of a machine, wherein the rotary
operating element (10) comprises:
- a shaft (12), wherein the shaft (12) is rotatable to provide a rotary control function
and wherein the shaft is actuatable in an axial direction of the shaft to provide
an axial control function, wherein the shaft (12) has a default position in the axial
direction; and
- a restoring assembly (15) configured to apply a restoring force in the axial direction
to the shaft (12) to return the shaft into the default position,
wherein the restoring assembly (15) is a magnetic restoring assembly that comprises
a first component (20) coupled to a housing (11) of the rotary operating element (10)
and a second component (30) provided on the shaft (12), wherein the first component
(20) and/or the second component (30) comprises a magnet (40), and wherein the first
component (20) and the second component (30) are configured to interact magnetically
to generate said restoring force when the shaft (12) is moved in axial direction out
of the default position.
2. The rotary operating element according to claim 1, wherein the shaft (12) is movable
from the default position in two axial directions including a pushing axial direction
and a pulling axial direction, wherein the magnetic restoring assembly (15) is configured
to generate the restoring force for movement of the shaft (12) in both axial directions.
3. The rotary operating element according to claim 1 or 2, wherein the magnetic restoring
assembly (15) is configured to provide a contactless interaction between the first
component (20) and the second component (30) to apply the restoring force to the shaft
(12).
4. The rotary operating element according to any of the preceding claims, wherein the
first component (20) has an annular shape including a though hole, wherein the shaft
(12) extends through the through hole, wherein in the default position, a first contour
(21) of a radially inwardly facing surface of the annular first component (20) faces
a second contour (31) of a radially outwardly facing surface of the second component
(30) provided on the shaft (12).
5. The rotary operating element according to claim 4, wherein the first contour (21)
and the second contour (31) are shaped to generate a force profile for the restoring
force that has a maximum (72, 71) at an axial position of the shaft (12) that is located
between the default position and an axial position of the shaft at an end stop (41,
42).
6. The rotary operating element according to claim 5, wherein the shaft (12) is actuatable
from the default position into a pushing axial direction to provide a push control
function and into a pulling axial direction to provide a pull control function, wherein
the first contour (21) and the second contour (31) are shaped such that the force
profile of the restoring force has a first respective maximum (72) when the shaft
(12) is moved in the pushing axial direction and has a second respective maximum (71)
when the shaft (12) is moved in the pulling axial direction.
7. The rotary operating element according to claim 6, wherein the restoring force at
the first maximum (72) is similar to or is different from the restoring force at the
second maximum (71).
8. The rotary operating element according to any of the preceding claims, wherein the
first component (20) comprises one, two, or more protrusions (25, 26) extending in
radial direction towards the shaft (12) and/or the second component (30) comprises
one, two, or more protrusions (35, 36, 39) extending in radial direction away from
the shaft (12), wherein at least in the default position of the shaft (12) at least
one of the protrusions (25, 26; 35, 36) of the respective component (20; 30) forms
part of a magnetic path towards the respective other component (30; 20).
9. The rotary operating element according to claim 8 when dependent on any of claims
4-7, wherein the first contour (21) is defined by the one, two, or more protrusions
(25, 26) of the first component (20) and/or wherein the second contour (31) is defined
by the one, two, or more protrusions (35, 36, 39) of the second component (30).
10. The rotary operating element according to claim 8 or 9, wherein at least two of the
protrusions (25, 26) on the first component (20) and/or at least two of the protrusions
(35, 36) on the second component (30) have a different extension in axial direction
configured to generate an asymmetric force profile of the restoring force.
11. The rotary operating element according to any of the preceding claims, wherein the
first component (20) comprises one, two, or more return rings (27, 28) that are arranged
concentrically with a rotational axis (13) of the shaft (12), wherein the shaft (12)
including the second component (30) is arranged radially inwardly of the one, two,
or more return rings (27, 28), wherein the one, two, or more return rings (27, 28)
form part of a magnetic path towards the second component (30).
12. The rotary operating element according to any of the preceding claims, wherein the
first component (20) comprises a ring magnet (40), wherein the ring magnet is concentric
with the shaft (12).
13. The rotary operating element according to any of the preceding claims, further comprising
a magnetic sensor (52) configured to detect a rotation of the shaft and/or to detect
an axial movement of the shaft, wherein the detection occurs contactlessly.
14. The rotary operating element according to claim 13, wherein the sensor (52) is a Hall
sensor.
15. A method of operating a rotary operating element (10) for a controlling a function
of a machine, wherein the rotary operating element (10) comprises a shaft (12), wherein
the shaft (12) is rotatable to provide a rotary control function and wherein the shaft
(12) is actuatable in an axial direction of the shaft to provide an axial control
function, wherein the shaft (12) has a default position in the axial direction; and
a restoring assembly (15) configured to apply a restoring force in the axial direction
to the shaft (12) to return the shaft (12) into the default position, wherein the
restoring assembly (15) is a magnetic restoring assembly that comprises a first component
(20) coupled to a housing (11) of the rotary operating element and a second component
(30) provided on the shaft, wherein the first component (20) and/or the second component
(30) comprises a magnet (40), and wherein method comprises:
- moving the shaft (12) in axial direction out of the default position; and
- generating said restoring force by magnetic interaction between the first component
(20) and the second component (30).