SHIFT DEVICE

A shift device is provided. The shift device comprises a first member axially movably supported on a shaft, a second member axially movably supported on the shaft, and an elastic member arranged on the shaft and elastically compressible in the axial direction of the shaft. The second member is engaged with the first member such that an axial movement of the first member is transmitted to the second member and vice versa via the elastic member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European patent application no. 23172173.9, filed May 9, 2023, the disclosure of which is hereby incorporated in its entirety by reference herein.

TECHNICAL FIELD

The present invention relates to a shift device, and in particular to a shift device for a shifting system.

BACKGROUND

In, for example, a vehicle transmission with an electrically actuated shifting system, it is important to prevent overloading of an actuator that performs a shift operation. To do this, conventionally, a shift device including a spring system is used. The spring system temporarily compensates for a shifting movement caused upon operation of the actuator, when a shift sleeve configured to engage and disengage gears of the transmission with a transmission shaft (e.g., a sliding collar or a dog clutch) is prevented from shifting during an engagement process with a corresponding gear, for example, due to a tooth-to-tooth position with the gear, or during a disengagement process with the gear, for example, due to torque still acting on the engagement between the shift sleeve and the gear. That is, even if the shifting of the shift sleeve is temporarily prevented, the actuator is allowed to complete the shifting movement and an overload of the actuator during the shift operation can be avoided. As a result, the spring system can prevent damage to the actuator and help prevent a reduction in its service life.

Conventionally, as shown inFIG.3, the shift device including the spring system uses two springs301,302(so-called blocker springs). When the actuator is operated and moves a first member100supported on a shaft400in a first axial direction A1(e.g., to the left inFIG.3), the movement is transmitted via the first spring301to a second member200supported on the shaft400and in communication with the shift sleeve. By compressing the first spring301in the axial direction, the spring system can temporarily compensate for the shifting movement, when the shifting of the shift sleeve is prevented, for example, due to tooth-to-tooth position with the gear. As a result, relative axial movement between the first and the second members100,200occurs. When the tooth-to-tooth position with the gear is released, the first spring301, being compressed, exerts an urging force (due to the elastic restoring force) on the first and second members100,200, which moves the second member200in the first axial direction A1and completes the shifting of the shift sleeve. When the actuator is operated and moves the first member100into a second axial direction A2(e.g., to the right inFIG.3) opposite to the first axial direction A1, the corresponding effect is achieved by the compression of the second spring302.

However, the conventional design of the shift device including the spring system is associated with disadvantages. Firstly, depending on the relative axial movement toward the first or the second axial direction A2, the elastic restoring force of either the first spring301or of the second spring302is applied. Consequently, the neutral position of the first member100with respect to the second member200is influenced by any difference in spring forces of the first and second springs301,302. Therefore, positional accuracy of the first member100with respect to the second member200is not sufficiently ensured, which may affect the shifting accuracy of the shift device. Furthermore, the requirements for the manufacturing tolerances of the springs301,302are very high. Additionally, by sequentially arranging the first and second springs301,302in the axial direction, an axial length of the spring system cannot be reduced without affecting the possible compensation distance for the axial movement. This conflicts with the generally desired goal of reducing the space required to be installed.

Therefore, there is a need for a compactly designed shift device including a spring system that provides improved shifting accuracy.

In view of the above, it is the object of the present invention to provide a compactly designed shift device that provides improved shifting accuracy.

SUMMARY

The object is achieved by a shift device having the features of independent claim1. A shifting system including the shift device according to the invention is subject matter of claim10. Further advantageous developments are set out in the dependent claims.

According to the invention, the axial movement of a first member supported on a shaft is transmitted to a second member supported on the shaft and vice versa via an elastic member. By compression of the elastic member, a relative axial movement between the first member and the second member is allowed in both the first axial direction and the second axial direction opposite to the first axial direction. That is, when the first member is axially moved relative to the second member in the first axial direction, the elastic member is compressed, and the elastic restoring force of the elastic member urges the first member back to its initial position relative to the second member. When the first member is moved axially relative to the second member in the second axial direction, also in this case, the elastic member is compressed and the elastic restoring force of the elastic member urges the first member back to its initial position relative to the second member.

Therefore, in the shift device according to the invention, regardless of whether a relative axial movement occurs between the first and the second members in the first or second axial direction, the elastic restoring force of the same elastic member is applied. As a result, it is ensured that the initial position of the first member relative to the second member, in particular a neutral position of the shift device, is always in the same position. Therefore, the positional accuracy of the shift device can be ensured, resulting in excellent shifting accuracy of the shift device.

The elastic member compensates for the relative axial movement between the first and the second member in both the first and the second axial directions. Therefore, an installation space required for the spring system can be reduced.

Optionally, the shift device may further include two inner sleeves, which are axially movably supported on the shaft. In addition, the first member may comprise an outer sleeve, which is disposed radially outwardly of the inner sleeves. The outer sleeve may be axially movably supported on the shaft via the two inner sleeves. The elastic member may be arranged between the two inner sleeves.

Accordingly, the two inner sleeves may serve as bearing portions for the first member including the outer sleeve. The two inner sleeves are spaced apart by the elastic member arranged between the two inner sleeves. As a result, an excellent bearing of the first member on the shaft can be ensured despite the reduced installation space required for the spring system of the shift device. Therefore, tilting of the first member (and thus, jamming of the sleeve on the shaft) can be effectively prevented.

Optionally, the inner sleeve may have an outer abutment projecting radially outwardly from an outer peripheral surface of the inner sleeve. The outer sleeve may have, at each axial end, an inner abutment projecting radially inwardly from an inner peripheral surface of the outer sleeve. An axial movement of the inner sleeve relative to the outer sleeve towards a position, in which the inner sleeve protrudes from the outer sleeve, is restricted by the outer abutment of the inner sleeve abutting the inner abutment of the outer sleeve. In addition, the clastic member may be disposed radially inside the outer sleeve so as to urge the outer abutments of the inner sleeves into contact with the inner abutments of the outer sleeve. Therefore, as long as the elastic resilient force of the elastic member is high enough to urge the outer abutments of the inner sleeves into contact with the inner abutments of the outer sleeve, the initial position (i.e., the neutral position) of the first member is dependent only on the geometrical dimensions of the inner sleeves and the outer sleeve. Thus, the influence of fluctuations of elastic characteristics of the elastic member on the initial position of the first member can be suppressed. As a result, excellent shifting accuracy of the shift device can be achieved while simultaneously achieving a reduced required installation space for the spring system of the shift device.

Optionally, the second member may include first and second bearing portions for axially movably supporting the second member on the shaft. The outer sleeve of the first member accommodating the elastic member, and the inner sleeves may be interposed between the first and second bearing portions of the second member. As a result, an excellent bearing of the second member on the shaft can be ensured while simultaneously achieving a reduced required installation space for the spring system of the shift device. Therefore, tilting of the second member can be effectively prevented.

Optionally, when the first member is in the initial position relative to the second member, one of the inner sleeves may abut the first bearing portion and the other of the inner sleeves may abut the second bearing portion. Therefore, the initial position (i.e., the neutral position) of the first member relative to the second member is dependent only on the geometrical dimensions of the inner sleeves, the outer sleeve of the first member and the bearing portions of the second member. Thus, the influence of fluctuations of elastic characteristics of the elastic member on the initial position of the first member relative to the second member can be suppressed. As a result, excellent shifting accuracy of the shift device can be achieved.

Optionally, the inner sleeve may include an axial protrusion partially covering an outer peripheral surface of an axial end portion of the elastic member. Therefore, the elastic member can be centered via the axial protrusion of the inner sleeve. Hence, centering or guiding of the elastic member via the shaft is not necessary. As a result, friction between the elastic member and the shaft can be reduced.

Optionally, an inner peripheral surface of the inner abutments of the outer sleeve of the first member may slidably contact the outer peripheral surface of the inner sleeve. Therefore, when the first member is displaced from the initial position relative to the second member, an excellent guidance and support of the first member moving axially relative to the second member can be achieved.

Optionally, the elastic member may include at least a first coil spring and a second coil spring arranged on a radially outer side of the first coil spring so as to circumferentially surround the first coil spring. As a result, depending on the purpose of use, various elastic characteristics can be appropriately chosen. In addition, compared to the use of only one coil spring, higher elastic restoring forces can be achieved.

Further benefits and advantages of the present invention will become apparent from the following detailed description of at least one exemplary embodiment for carrying out the present invention with reference to the accompanying drawings.

DETAILED DESCRIPTION

A first embodiment of the present invention is described below with reference toFIG.1.

FIG.1illustrates a schematic sectional view of the shift device according to the first embodiment. The shift device allows a relative axial movement between a first member1and a second member2and provides an elastic restoration to the initial position. In the first embodiment, the shift device is exemplified for the use in an electrically actuated shifting system. However, the shift device according to the invention is not limited to the use in the electrically actuated shifting system. In particular, the shift device according to the invention can be implemented in various fields, where a relative movement between two members and an elastic restoration to the initial position is required.

The shift device includes the first member1, which is axially movably supported on a shaft4. The first member1is in communication with an actuator of the shifting system (not shown) via a coupling mechanism, so that when the actuator is actuated, the first member1is shifted in the axial direction of the shaft4. Depending on the control of the actuator, an axial movement of the first member1can be made in one axial direction (a first axial direction A1) or the other axial direction (a second axial direction A2) opposite to the first axial direction A1.

The first member1comprises an outer sleeve11. The outer sleeve11is disposed so as to surround the shaft4at least partially in the circumferential direction. That is, the outer sleeve11may have a partially opened circumferential portion. At each axial end portion of the outer sleeve11, an inner abutment111is formed by a protrusion projecting radially inwardly from an inner peripheral surface of the outer sleeve11. The inner abutments111extend in a circumferential direction of the outer sleeve11.

The first member1further comprises a coupling portion for coupling with the coupling mechanism. As shown inFIG.1, the coupling portion is formed on an axial end portion (on the right end portion inFIG.1). However, the design of the coupling portion is not limited to this and can be appropriately provided, e.g., on an axial central portion of the outer sleeve11.

The shift device further includes two inner sleeves5, which are axially movably supported on the shaft4. The inner sleeves5are disposed so as to surround the shaft4at least partially in the circumferential direction. The inner sleeves5are disposed radially inwardly with respect to the outer sleeve11. In particular, a diameter of an outer peripheral surface of the inner sleeves5is smaller than a diameter of an inner peripheral surface of the outer sleeve11.

Furthermore, one of the two inner sleeves5is axially arranged such that one axial end portion of the inner sleeve5is disposed inside the outer sleeve11. That is, one of the axial end portions of the outer sleeve11radially overlaps with the axial end portion of the inner sleeve5disposed inside the outer sleeve11. Correspondingly, also the other of the two inner sleeves5is axially arranged such that one axial end portion of the inner sleeve5is disposed inside the outer sleeve11. That is, the other of the axial end portions of the outer sleeve11radially overlaps with the axial end portion of the other of the inner sleeve5disposed inside the outer sleeve11. The axial end portions of the inner sleeves5, which are not disposed inside the outer sleeve11, protrude from the outer sleeve11in the axial direction.

As mentioned above, the outer sleeve11is axially movably supported on the shaft4. This support is provided via the two inner sleeves5. In particular, an inner peripheral surface of the inner abutments111of the outer sleeve11slidably contacts the outer peripheral surface of the respective inner sleeve5. Therefore, the inner sleeves5are axially movable with respect to the outer sleeve11.

An outer abutment51is formed on each of the inner sleeves5at the axial end portion disposed inside the outer sleeve11. The outer abutment51projects radially outwardly from the outer peripheral surface of the inner sleeve5and extends in the circumferential direction of the inner sleeve5. An outer diameter of the outer abutment51of the inner sleeve5is larger than an inner diameter of the inner abutment111of the outer sleeve1. Therefore, when the inner sleeve5is axially moved relative to the outer sleeve11in the axial direction, in which the inner sleeve protrudes from the outer sleeve, the outer abutment51of the inner sleeve5engages with the respective inner abutment111of the outer sleeve11, thereby restricting the axial movement of the inner sleeve5relative to the outer sleeve11.

An axial protrusion52is formed on an outer circumferential edge portion of the outer abutment51on an axial end side of the inner sleeve5. The axial protrusion52partially covers an outer peripheral surface of an axial end portion of an elastic member3described below.

The shift device further comprises an elastic member3. According to the first embodiment shown inFIG.1, a coil spring is used as the elastic member3. However, the present invention is not limited thereto. For example, plate springs or rubber members can be used as the elastic member3. The elastic member3is elastically compressible in the axial direction.

The elastic member3is arranged concentrically around the shaft4so as to be axially aligned with the shaft4. The elastic member3is arranged radially inside of the outer sleeve11of the first member1. Furthermore, the elastic member3is arranged between the two inner sleeves5with respect to the axial direction. The elastic member3urges the two inner sleeves5in the direction in which the respective inner sleeve5protrudes out of the outer sleeve11. That is, the elastic member3(i.e., an elastic restoring force) urges the outer abutments51of the inner sleeves5into contact with the respective inner abutment111of the outer sleeve11. Furthermore, by compression of the elastic member3, the inner sleeves5can be axially moved with respect to the outer sleeve11in a direction opposite to the direction in which the respective inner sleeve5protrudes out of the outer sleeve11.

Outer peripheral surfaces of the axial end portions of the elastic members3are at least partially covered by the axial protrusion52of the inner sleeve5. The axial protrusions52serve for axial centering of the elastic member3.

The shift device includes the second member2, which is axially movably supported on the shaft4. The second member2is in communication with a shift member of the shifting system, such as a shift fork and/or a shift sleeve (e.g., a sliding collar or a dog clutch). The second member2includes a first bearing portion21and a second bearing portion22. The first and second bearing portions21,22serve for axially movably supporting the second member2on the shaft4. In particular, the first and second bearing portions21,22are formed substantially in a ring shape coaxially arranged with the shaft4.

The first bearing portion21and the second bearing portion22are spaced apart from each other in the axial direction. The outer sleeve11of the first member1and the inner sleeves5are interposed between the first bearing portion21and the second bearing portion22. In particular, a axial distance from an axial end side of the first bearing portion21facing the second bearing portion22to an axial end side of the second bearing portion22facing the first bearing portion21is substantially equal to a distance from an axial end side of one inner sleeve5facing the first bearing portion21to an axial end side of the other inner sleeve5facing the second bearing portion22, when the outer abutments51of the inner sleeves5contact the respective inner abutment111of the outer sleeve11. Consequently, in a state, in which the outer abutments51of the inner sleeves5contact the respective inner abutment111of the outer sleeve11, the axial end side of one inner sleeve5contacts the axial end side of the first bearing portion21facing the second bearing portion22, and the axial end side of the other inner sleeve5contacts the axial end side of the second bearing portion22facing the first bearing portion22.

In the following, operation of the shift device according to the first embodiment of the present invention is described with reference toFIG.1.

In the shift device according to the first embodiment described above, the second member2is engaged with the first member1such that an axial movement of the first member1is transmitted to the second member2via the elastic member3. In particular, when the first member1is moved axially toward the first axial direction A1(e.g., to the left inFIG.1) upon operation of the actuator of the shifting system, the axial movement of the first member1is transmitted to one of the two inner sleeves5(e.g., the right inner sleeve5inFIG.1) via the engagement of the inner abutment111of the outer sleeve11with the outer abutment51of the inner sleeve5. The axial movement of the one inner sleeve5is transmitted to the other inner sleeve5(e.g., the left inner sleeve5inFIG.1) via the elastic member3. The axial movement of the other inner sleeve5is transmitted to the second member2via one of the first and second bearing portions21,22(e.g., the first bearing portion21) being in contact with the other inner sleeve5. As a result, the second member22axially moves the shift member and, for example, a shift sleeve connected to the shift member is engaged with a gear of a manual transmission.

In the shifting process described above, the first member1and the second member2both move axially with respect to the shaft. That is, the first member1does not move axially relative to the second member2. Thus, the first member1remains in an initial position (i.e., a neutral position) relative to the second member2, as it is shown inFIG.1.

In the following, the shifting process is described for a situation when the axial movement of the shift member of the shifting system is restricted, for example, due to a tooth-to-tooth position with the gear.

Initially, the axial movement is transmitted from the first element1to the second element2as described above. However, when the axial movement of the shift member connected to the second member2is restricted, the axial movement of the second member2is also restricted. As a result, the axial movement of the inner sleeve5, which is provided on the axial end side of the outer sleeve11facing in the axial moving direction of the first member1, is restricted by contacting one of the first and second bearing portions21,22of the second member2. The inner sleeve5, which is provided on the axial end side of the outer sleeve11facing opposite to the axial moving direction of the first member1, is still moved axially by the engagement of the outer abutment52with the inner abutment111of the outer sleeve11. Therefore, the elastic member3is compressed between the two inner sleeves5. As a result, the first member1moves axially while the second member2does not move axially. That is, the first member1is moved axially relative to the second member2and deviates from its initial position relative to the second member2.

When the first member1is moved in the first axial direction A1relative to the second member2, the inner sleeve5provided on the axial end side of the outer sleeve11in the first axial direction A1is displaced relative to the outer sleeve11so as to space the outer abutment51from the respective inner abutment111. The inner sleeve5provided on the axial end side of the outer sleeve11in the second axial direction A2is displaced from the second bearing portion22so as to space the inner sleeve5from the second bearing portion22.

Correspondingly, when the first member1is moved in the second axial direction A2relative to the second member2, the inner sleeve5provided on the axial end side of the outer sleeve11in the second axial direction A2is displaced relative to the outer sleeve11so as to space the outer abutment51from the respective inner abutment111. The inner sleeve5provided on the axial end side of the outer sleeve11in the first axial direction A1is displaced from the first bearing portion21so as to space the inner sleeve5from the second bearing portion21.

Therefore, the elastic member3, by being compressed, allows relative axial movement in both the first axial direction A1and the opposite second axial direction A2between the first member1and the second member2so that one of the first member1and the second member2is displaced from an initial position relative to the other of the first member and the second member2.

The elastic member3is appropriately adapted to compensate for the relative axial movement of the first member1with respect to the second member2without interrupting the operation of the actuator before the intended end position is reached. Typical dimensions for the axial movement during the shifting process (i.e., a specific amount) are, for example, about 11 mm. Therefore, the elastic member3is designed to be compressible by at least about 11 mm (i.e., the specific amount) when the elastic member3is arranged inside the outer sleeve11and between the two inner sleeves5(i.e., in an installed state). The tooth-to-tooth position occurs, for example, after an axial movement of about 2 mm. Consequently, the elastic member3is able to compensate for the relative movement between the first member1and the second member2, which is, for example, approximately 9 mm.

When the restriction on the axial movement of the shift member is released (e.g., the tooth-to-tooth position is released), the elastic restoring force of the elastic member3urges the first member1in the second axial direction A2and the second member2in the first axial direction A1(according to the above-described example). Consequently, the second member2is axially moved, thereby axially moving the shift member so as to complete the shifting process of the shift member.

In particular, the elastic restoring force of the elastic member3ensures that the first member1is moved axially to its initial position relative to the second member2, when the axial movement of the second member2(i.e., the shift member) is no longer restricted. Thus, after the restriction of the axial movement is removed, the shift device returns to the initial position described above.

According to the first embodiment of the present invention, the first member1communicates with the actuator of the shifting system and the second member2communicates with the shift member of the shifting system. However, the first embodiment can be modified so that the second member2communicates with the actuator and the first member1communicates with the shift member. This arrangement also provides the same effects and advantages as the first embodiment.

A second embodiment of the present invention is described below with reference toFIG.2.

The second embodiment differs from the first embodiment in that the elastic member3comprises a first coil spring31and a second coil spring32. The second coil spring32is arranged on a radially outer side of the first coil spring32. The first coil spring31and the second coil spring32are arranged axially aligned with the shaft4. The first coil spring31and the second coil spring32are axially arranged between the two inner sleeves5and radially inside of the outer sleeve5.

By providing of the first coil spring31and the second coil spring32, higher elastic restoring forces can be achieved compared to using only one coil spring. In addition, the same effects and advantages can be achieved as with the first embodiment.

The above-described embodiments of the present invention can be appropriately modified or combined. The above description is not exhaustive, and the present invention is not limited to the above embodiments. The skilled person will recognize that various modifications and combinations of the features included in the above embodiments are possible within the scope of the invention. Accordingly, the scope of the invention should be determined from the accompanying claims.