Drive device for electric vehicle

Abstract

In a drive device for an electric vehicle capable of switching the reduction ratio between high and low levels in two stages, a structure is realized that can smoothly switch the mode of the rotation transmission state switching device even during regenerative running when regenerative torque acts on the drive motor. The control device of the drive device for an electric vehicle, in accordance with the mode switching of the two-speed transmission (3) by the reduction ratio switching function, before pressing one of the engaging claws (94 or 97) that extends from the base (93 (or 96)) pivotally supported by the second member (75) toward the other side in the circumferential direction by the protrusion (100) to retract it from the engaging recess (77), while reducing the regenerative torque of the drive motor (2), a cooperative control function is provided that executes a pre-shift process of increasing the braking force by the friction braking device (5).

Description

Technical Field

[0001] The present disclosure relates to a drive device for an electric vehicle that increases the output torque (decelerates rotation) of an electric motor and transmits it to drive wheels.

Background Art

[0002] In response to the recent trend of reducing fossil fuel consumption, research on electric vehicles and hybrid vehicles has progressed and is being partially implemented. An electric motor, which is a power source for electric vehicles and hybrid vehicles, differs from an internal combustion engine (engine) that operates by directly burning fossil fuel. The characteristics of the torque and rotational speed of the output shaft are preferable for automotive use (generally, maximum torque is generated at startup). Therefore, it is not always necessary to provide a transmission like that of a general automobile with an internal combustion engine as a drive source.

[0003] However, even when an electric motor is used as a drive source, the acceleration performance and high-speed performance can be improved by providing a transmission. Specifically, by providing a transmission, the relationship between the traveling speed and acceleration of the vehicle can be made smooth, similar to that of a gasoline-engine vehicle equipped with a transmission in the power transmission system. This will be described with reference to FIG. 36.

[0004] For example, if a power transmission device with a large reduction ratio is arranged between the output shaft of the electric motor and the input part of the differential gear connected to the drive wheels, the relationship between the acceleration (G) and traveling speed (km / h) of the electric vehicle will be as shown by the solid line a in FIG. 36. That is, the acceleration performance at low speeds is excellent, but high-speed traveling becomes impossible. On the other hand, if a power transmission device with a small reduction ratio is arranged between the output shaft and the input part, this relationship will be as shown by the dashed line b in FIG. 36. That is, high-speed traveling becomes possible, but the acceleration performance at low speeds is impaired.

[0005] On the other hand, if a transmission is provided between the output shaft and the input section and the reduction ratio of this transmission is changed according to the vehicle speed, characteristics can be obtained such that the left side portion of the solid line a from point P and the right side portion of the chain line b from point P are made continuous. These characteristics are almost equivalent to those of a gasoline engine vehicle having the same level of output shown by the broken line c in Fig. 36, and it can be seen that acceleration performance and high speed performance can obtain performance equivalent to that of a gasoline engine vehicle provided with a transmission in the power transmission system.

[0006] International Publication No. 2023 / 135870 discloses a structure of a drive device for an electric vehicle that increases the output torque of a drive motor as a drive source and transmits it to a differential gear by means of a two-stage transmission provided with a friction engagement device capable of switching between a connection mode and a disconnection mode, and a rotational transmission state switching device capable of switching between a lock mode, a one-way clutch mode, and a free mode. In this drive device for an electric vehicle, by switching the mode of the friction engagement device and the mode of the rotational transmission state switching device, it is possible to switch the two-stage transmission between a low reduction ratio mode in which the reduction ratio between the input member and the output member is small and a high reduction ratio mode in which the reduction ratio is larger than that in the low reduction ratio mode.

[0007] Specifically, by switching the electric friction clutch device to the disconnection mode and switching the rotational transmission state switching device to the lock mode, the two-stage transmission can be switched to the high reduction ratio mode, and by switching the electric friction clutch device to the connection mode and switching the rotational transmission state switching device to the free mode, the two-stage transmission can be switched to the low reduction ratio mode.

[0008] In the drive device for an electric vehicle described in International Publication No. 2023 / 135870, when switching from the high reduction ratio mode to the low reduction ratio mode during normal forward driving (power running), after switching the rotational transmission state switching device from the lock mode to the one-way clutch mode, the friction engagement device is switched from the disconnection mode to the connection mode. This prevents the occurrence of shock (shift shock) when switching the reduction ratio.

[0009] The rotational transmission state switching device that constitutes this drive device for an electric vehicle includes a first member, a second member, a mode selection member, a first claw member, a second claw member, a first claw biasing member, and a second claw biasing member.

[0010] The first member has engagement recesses at a plurality of locations in the circumferential direction on its outer peripheral surface.

[0011] The second member is arranged coaxially with the first member around the first member.

[0012] The mode selection member has protrusions that project radially at a plurality of locations in the circumferential direction, and rotates along with the rotation of a drive cam for switching a friction clutch device.

[0013] The first claw member has a first base portion pivotally supported by the second member and a first engagement claw that extends from the first base portion toward the first side in the circumferential direction.

[0014] The second claw member has a second base portion pivotally supported by the second member and a second engagement claw that extends from the second base portion toward the second side in the circumferential direction.

[0015] The first claw biasing member elastically biases the first engagement claw in a direction to engage with the engagement recess.

[0016] The second claw biasing member elastically biases the second engagement claw in a direction to engage with the engagement recess.

[0017] This rotational transmission state switching device switches between a free mode, a lock mode, and a one-way clutch mode as the mode selection member rotates.

[0018] Specifically, when switching the rotational transmission state switching device to the free mode, the mode selection member is rotated, and the protrusions push up the first engagement claw and the second engagement claw radially outward to retract them from the engagement recesses, thereby allowing the rotation of the first member relative to the second member regardless of the relative rotational direction between the first member and the second member.

[0019] When switching the rotation transmission state switching device to the lock mode, the protruding portion is positioned at a portion circumferentially disengaged from the first engaging claw and the second engaging claw, and the first engaging claw and the second engaging claw are engaged with the engaging recess, thereby preventing the rotation of the first member with respect to the second member regardless of the relative rotation direction between the first member and the second member.

[0020] When switching the rotation transmission state switching device to the one-way clutch mode, only the second engaging claw is pushed radially outward by the protruding portion and retracted from the engaging recess, thereby allowing only the rotation of the first member in a predetermined direction with respect to the second member and preventing the rotation in the direction opposite to the predetermined direction.

Prior Art Documents

Patent Documents

[0021]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0022] In the drive device for an electric vehicle described in International Publication No. 2023 / 135870, when switching from the high reduction ratio mode to the low reduction ratio mode during regenerative braking in which regenerative torque acts on the drive motor, it is necessary to switch the rotation transmission state switching device from the lock mode to the one-way clutch mode and further to the free mode.

[0023] Here, when the vehicle is performing regenerative driving forward in the high reduction ratio mode, a torque in the direction opposite to the predetermined direction, that is, the direction in which rotation is blocked by the rotation transmission state switching device, is applied to the first member. For this reason, the circumferential side surface of the engagement recess provided in the first member is strongly pressed against the tip of the first engagement claw. Therefore, in order to switch the rotation transmission state switching device from the lock mode to the one-way clutch mode, the force required to press the first engagement claw radially outward by the protruding portion may become excessive, and in extreme cases, it may not be possible to switch the mode of the rotation transmission state switching device.

[0024] If a motor with a large output is used as the shift motor that rotationally drives the drive cam, the mode of the rotation transmission state switching device can be switched regardless of the torque applied to the first member during regenerative driving forward in the high reduction ratio mode, but there is a problem that the shift motor becomes larger.

[0025] In view of the above circumstances, an object of the present disclosure is to realize a structure capable of smoothly switching the mode when switching from the low reduction ratio mode to the high reduction ratio mode during regenerative running in an electric vehicle drive device capable of switching the reduction ratio between two levels, when a regenerative torque acts on the drive motor.

Means for Solving the Problem

[0026] An electric vehicle drive device according to an aspect of the present disclosure includes a drive motor, a two-stage transmission, a torque transmission mechanism, a friction brake device, and a control device.

[0027] The drive motor has a motor output shaft.

[0028] The two-stage transmission has an input member, an output member, a rotating member, an electric friction clutch device, and a rotation transmission state switching device.

[0029] Torque transmission is possible between the input member and the motor output shaft.

[0030] The output member is supported so as to be rotatable relative to the input member.

[0031] The rotating member is supported so as to be rotatable relative to the input member and the output member.

[0032] The electric friction clutch device includes a first clutch member, a second clutch member, a friction engagement portion, a cam device, and an electric actuator.

[0033] The first clutch member rotates integrally with the rotating member or is constituted by the rotating member itself.

[0034] The second clutch member is supported coaxially with the first clutch member so as to be rotatable relative to the first clutch member, and rotates integrally with the input member or the output member, or is constituted by the input member or the output member itself.

[0035] The friction engagement portion includes at least one first friction plate and at least one second friction plate supported so as to be axially displaceable relative to each other, and is provided between the first clutch member and the second clutch member.

[0036] The cam device includes a driving cam and a driven cam supported so as to be rotatable and axially displaceable relative to the driving cam. The cam device expands and contracts the axial distance between the driving cam and the driven cam as the driving cam rotates.

[0037] The electric actuator includes a shift motor and a speed reducer, and the shift motor rotationally drives the driving cam via the speed reducer.

[0038] The electric friction clutch device is configured to be able to switch between a connection mode in which torque is transmitted between the first clutch member and the second clutch member by pressing the at least one first friction plate and the at least one second friction plate against each other based on expanding or contracting the axial dimension of the cam device, and a disconnection mode in which torque is not transmitted between the first clutch member and the second clutch member by releasing the force pressing the at least one first friction plate and the at least one second friction plate against each other.

[0039] The rotational transmission state switching device includes a first member, a second member, a mode selection member, a first claw member, a second claw member, a first claw biasing member, and a second claw biasing member.

[0040] The first member has engagement recesses at a plurality of locations in the circumferential direction.

[0041] The second member is arranged coaxially with the first member.

[0042] The mode selection member has protrusions protruding in the radial direction or the axial direction at a plurality of locations in the circumferential direction, and rotates or is displaced in the axial direction as the drive cam rotates.

[0043] The first claw member includes a first base portion pivotally supported by the second member, and extends from the first base portion toward the first side in the circumferential direction.

[0044] The second claw member includes a second base portion pivotally supported by the second member, and a second engagement claw extending from the second base portion toward the second side in the circumferential direction.

[0045] The first claw biasing member elastically biases the first engagement claw in a direction to engage with the engagement recess.

[0046] The second claw biasing member elastically biases the second engagement claw in a direction to engage with the engagement recess.

[0047] One of the first member and the second member rotates integrally with the rotating member or is constituted by the rotating member itself. The other member of the first member and the second member is supported so as not to be relatively rotatable with respect to a fixed portion that does not rotate even during use.

[0048] The rotation transmission state switching device is configured to be able to switch between at least one of a lock mode and a one-way clutch mode and a free mode.

[0049] In the lock mode, the protruding portion is positioned at a position deviated from the first engaging claw and the second engaging claw in the circumferential direction or the axial direction, and the first engaging claw and the second engaging claw are engaged with the engaging recess, thereby preventing relative rotation between the first member and the second member regardless of the relative rotation direction between the first member and the second member.

[0050] In the one-way clutch mode, the protruding portion presses only one of the first engaging claw and the second engaging claw in the radial direction or the axial direction to retract it from the engaging recess, and engages the other engaging claw with the engaging recess, thereby allowing only rotation of one member in a predetermined direction with respect to the other member and preventing rotation of one member in a direction opposite to the predetermined direction with respect to the other member.

[0051] In the free mode, the protruding portion presses the first engaging claw and the second engaging claw in the radial direction or the axial direction to retract them from the engaging recess, thereby allowing relative rotation between the first member and the second member regardless of the relative rotation direction between the first member and the second member.

[0052] The torque transmission mechanism transmits torque between the output member and the drive wheel.

[0053] The friction brake device is disposed between the output member and the drive wheel to brake the rotation of the drive wheel.

[0054] The control device includes a reduction ratio switching function and a cooperative control function.

[0055] Based on the rotation drive of the drive cam by the electric actuator, the reduction ratio switching function switches the mode of the friction engagement portion and the mode of the rotation transmission state switching device, thereby switching the two-speed transmission between a high reduction ratio mode with a large reduction ratio between the input member and the output member and a low reduction ratio mode with a small reduction ratio between the input member and the output member.

[0056] In the cooperative control function, when torque is passing from the output member side to the input member side of the two-speed transmission, a torque is applied to one of the members to rotate the one member in the one circumferential direction with respect to the other member, and the rotation of the one member in the one circumferential direction with respect to the other member is blocked by the rotation transmission state switching device, before the engaging claw extending from the base portion pivotally supported by the second member in the other circumferential direction is pressed radially or axially by the protruding portion to be retracted from the engaging recess in accordance with the mode switching of the two-speed transmission by the reduction ratio switching function, a pre-shift process is executed to increase the braking force of the friction brake device while reducing the regenerative torque of the drive motor.

[0057] In the drive device for an electric vehicle according to one aspect of the present disclosure, in the pre-shift process, the regenerative torque of the drive motor can be reduced until it becomes zero.

[0058] In the drive device for an electric vehicle according to the first aspect of the present disclosure, the two-speed transmission can be configured to be capable of switching to the lock mode. In this case, the reduction ratio switching function switches the two-speed transmission to the high reduction ratio mode by switching the electric friction clutch device to the disconnection mode and switching the rotation transmission state switching device to the lock mode, and switches the two-speed transmission to the low reduction ratio mode by switching the electric friction clutch device to the connection mode and switching the rotation transmission state switching device to the free mode.

[0059] In the drive device for an electric vehicle according to one aspect of the present disclosure, the two-speed transmission can be configured to be capable of switching to the one-way clutch mode. In this case, during the switching of the two-speed transmission from the high reduction ratio mode to the low reduction ratio mode, the cooperative control function can be executed before the rotation transmission state switching device is switched from the lock mode to the one-way clutch mode.

[0060] In the drive device for an electric vehicle according to one aspect of the present disclosure, the cooperative control function performs the pre-shift process, and further, after pressing the one engagement claw radially or axially by the protrusion and retracting it from the engagement recess, increases the drive torque of the drive motor in the same direction as the direction of the regenerative torque acting on the drive motor, thereby promoting a decrease in the rotational speed of the motor output shaft. Then, when the rotational speed of the motor output shaft starts to decrease, an inertia process of decreasing the drive torque of the drive motor can be executed.

[0061] In the drive device for an electric vehicle according to one aspect of the present disclosure, after performing the inertia process, the cooperative control function sets the fastening force of the friction engagement portion to a magnitude such that the torque that can be transmitted without the at least one first friction plate and the at least one second friction plate slipping relative to each other is equal to or greater than the torque that passes through the friction engagement portion after completion of the switching of the two-speed transmission to the low reduction ratio mode. Further, thereafter, a shift completion process can be executed in which the regenerative torque of the drive motor is increased while reducing the braking force by the friction brake device.

[0062] In the drive device for an electric vehicle according to one aspect of the present disclosure, the electric friction clutch device can have a return spring that elastically biases the at least one first friction plate and the at least one second friction plate in a direction to separate them from each other.

[0063] In the drive device for an electric vehicle according to one aspect of the present disclosure, the electric friction clutch device is provided between the first clutch member or the second clutch member and the friction engagement portion, and can further include an elastic biasing mechanism that elastically biases the at least one first friction plate and the at least one second friction plate in a direction to press against each other.

[0064] Alternatively, in the drive device for an electric vehicle according to one aspect of the present disclosure, the electric friction clutch device is disposed between the friction engagement portion and the driven cam, and can further include an elastic biasing mechanism that elastically biases the friction engagement portion and the driven cam in a direction to move away from each other.

[0065] In the drive device for an electric vehicle according to one aspect of the present disclosure, the two-speed transmission can further include a planetary gear mechanism having a sun gear, a ring gear disposed coaxially with the sun gear around the sun gear, a carrier supported to enable relative rotation with respect to the sun gear and the ring gear, and a plurality of planetary gears meshing with the sun gear and the ring gear and supported by the carrier to enable rotation about its own central axis.

[0066] In this case, an input element, which is any one of the sun gear, the ring gear, and the carrier, is connected to the input member so as to rotate integrally with the input member.

[0067] An output element, which is any one of the sun gear, the ring gear, and the carrier and is an element different from the input element, is connected to the output member so as to rotate integrally with the output member.

[0068] A rotating element, which is the remaining element excluding the input element and the output element among the sun gear, the ring gear, and the carrier, is connected to the rotating member so as to rotate integrally with the rotating member.

Advantages of the Invention

[0069] According to the drive device for an electric vehicle of one aspect of the present disclosure, even during regenerative running in which regenerative torque acts on the drive motor, the mode switching of the rotation transmission state switching device can be smoothly performed.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0071] [First Example] The first example of the embodiment of the present disclosure will be described with reference to FIGS. 1 to 29.

[0072] The drive device 1 for an electric vehicle includes a drive motor 2, a two-speed transmission 3, a torque transmission mechanism 4, a friction brake device 5, and a control device 6.

[0073] The drive motor 2 has a motor output shaft 7.

[0074] Note that a positive value of the torque (T2) of the drive motor 2 means that it is an output torque (drive torque, power running torque), and a negative value of the torque (T2) means that it is a regenerative torque. In the following description, the torque (T2) with a positive value may be expressed as an output torque, and the torque (T2) with a negative value may be expressed as a regenerative torque.

[0075] The two-speed transmission 3 includes an input member 8, an output member 9, a rotating member 10, an electric friction clutch device 11, and a rotational transmission state switching device 12.

[0076] Regarding the two-speed transmission 3, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the input member 8. The axial direction, radial direction, and circumferential direction of the input member 8 coincide with the axial direction, radial direction, and circumferential direction of the output member 9, and also coincide with the axial direction, radial direction, and circumferential direction of the rotating member 10. Also, one side in the axial direction refers to the right side in FIGS. 2, 3(A), 3(B), 5, 7, 11, 15(A) to 15(D), and FIGS. 23 to 25, and the other side in the axial direction refers to the left side in FIGS. 2, 3(A), 3(B), 5, 7, 11, 15(A) to 15(D), and FIGS. 23 to 25.

[0077] The two-speed transmission 3 is configured to be able to switch between a high reduction ratio mode in which the reduction ratio between the input member 8 and the output member 9 is large and a low reduction ratio mode in which the reduction ratio between the input member 8 and the output member 9 is small by switching the mode of the electric friction clutch device 11 and the mode of the rotational transmission state switching device 12 to switch the torque transmission path. In this example, the two-speed transmission 3 switches between the high reduction ratio mode and the low reduction ratio mode by switching the mode of the electric friction clutch device 11 and the mode of the rotational transmission state switching device 12 to switch the torque transmission path passing through the planetary gear mechanism 13.

[0078] The input member 8 is capable of transmitting torque to and from the motor output shaft 7. Specifically, the input member 8 has an input gear 16 at one end in the axial direction that meshes with a drive gear 15 provided on the motor output shaft 7 of the drive motor 2.

[0079] In this example, the input member 8 is constituted by, for example, a housing that houses the two-speed transmission 3, and is rotatably supported by a rolling bearing (not shown) or the like with respect to a fixed portion 14 that does not rotate even during use. Further, the input member 8 is configured in a cylindrical (hollow) shape.

[0080] The output member 9 is supported so as to be capable of relative rotation with respect to the input member 8.

[0081] In this example, the output member 9 is arranged coaxially with the input member 8, and is supported so as to be capable of relative rotation with respect to the input member 8 via a rolling bearing (not shown) or the like inside the input member 8 in the radial direction. Further, the output member 9 has an output gear 17 at one end in the axial direction.

[0082] The rotating member 10 is supported so as to be capable of relative rotation with respect to the input member 8 and the output member 9.

[0083] In this example, the rotating member 10 is arranged coaxially with the input member 8 and the output member 9, and is rotatably supported with respect to the fixed portion 14 via a rotation transmission state switching device 12, a cam device 31 that constitutes the electric friction clutch device 11, and a radial bearing 42 for rotatably supporting a drive cam 38 that constitutes the cam device 31 with respect to the rotating member 10.

[0084] Specifically, the rotating member 10 has a small-diameter flange portion 18 protruding radially outward at an axially intermediate portion, and has a flange portion 19 protruding radially outward at a portion located on the other axial side (the left side in FIG. 2) of the small-diameter flange portion 18. The flange portion 19 has a hollow circular plate-shaped first ring portion 21, a first cylindrical portion 22 bent from the radially outer end portion of the first ring portion 21 toward the other axial side, a hollow circular plate-shaped second ring portion 23 bent from the axially other end portion of the first cylindrical portion 22 radially outward, and a second cylindrical portion 24 bent from the radially outer end portion of the second ring portion 23 toward the other axial side. The first ring portion 21 has partial arc-shaped through holes 20 for inserting partial cylindrical portions 67 of pressing members 62 constituting the electric friction clutch device 11 at a plurality of radially intermediate portions.

[0085] In this example, the rotating member 10 is configured by externally fitting and fixing a stepped cylindrical member 26 to a shaft member 25 having a small-diameter flange portion 18. That is, as shown in FIGS. 14(A) and 14(B), the stepped cylindrical member 26 has a flange portion 19 and a small-diameter cylindrical portion 27 bent from the radially inner end portion of the first ring portion 21 of the flange portion 19 toward the other axial side. The rotating member 10 supports and fixes the stepped cylindrical member 26 to the shaft member 25 by spline-engaging a female spline portion 28 provided on the inner peripheral surface of the small-diameter cylindrical portion 27 with a male spline portion provided on the outer peripheral surface of the shaft member 25. However, the rotating member may be configured by coupling and fixing the stepped cylindrical member and the shaft member by press-fitting, welding, or the like.

[0086] The electric friction clutch device 11 has a first clutch member, a second clutch member, a friction engagement portion 29, a cam device 31, and an electric actuator 32, and is provided between the rotating member 10 and the input member 8 or the output member 9. The electric friction clutch device 11 switches between a connection mode for transmitting torque between the first clutch member and the second clutch member and a disconnection mode for not transmitting torque.

[0087] The first clutch member is connected to rotate integrally with the rotating member 10 or is constituted by the rotating member 10 itself. In this example, the first clutch member is constituted by the rotating member 10 itself.

[0088] The second clutch member is supported coaxially with the first clutch member so as to be capable of relative rotation with respect to the first clutch member. Further, the second clutch member is connected to rotate integrally with the input member 8 or the output member 9 or is constituted by the input member 8 or the output member 9 itself. In this example, the second clutch member is constituted by the input member 8 itself.

[0089] The friction engagement portion 29 has at least one first friction plate 33 and at least one second friction plate 34 supported to enable relative displacement in the axial direction, and is provided between the rotating member 10 which is the first clutch member and the input member 8 which is the second clutch member.

[0090] In this example, at least one first friction plate 33 is constituted by a plurality of first friction plates 33, and at least one second friction plate 34 is constituted by a plurality of second friction plates 34. More specifically, the friction engagement portion 29 is constituted by a multi-plate clutch in which a plurality of first friction plates 33 supported by the rotating member 10 and a plurality of second friction plates 34 supported by the input member 8 are alternately stacked.

[0091] The plurality of first friction plates 33 are supported on the outer peripheral surface of the first cylindrical portion 22 so as to be axially displaceable and non-rotatable relative to the first cylindrical portion 22.

[0092] The plurality of second friction plates 34 are supported on the inner peripheral surface of the end portion on the other axial side of the input member 8 so as to be axially displaceable and non-rotatable relative to the input member 8.

[0093] The cam device 31 has a drive cam 38 and a driven cam 39 that is supported so as to be capable of relative rotation and axial relative displacement with respect to the drive cam 38. As the drive cam 38 rotates, the cam device 31 expands and contracts the axial distance between the drive cam 38 and the driven cam 39.

[0094] The cam device 31 can adopt any configuration as long as it can expand and contract the axial distance between the drive cam 38 and the driven cam 39, that is, the axial dimension of the cam device 31, as the drive cam 38 rotates. For example, the cam device may have a configuration in which a drive cam surface provided on the drive cam directly slides on a driven cam surface provided on the driven cam, a configuration in which a plurality of rolling elements are sandwiched between the drive cam surface provided on the drive cam and the driven cam surface provided on the driven cam, or a configuration in which a plurality of rolling elements supported by one of the drive cam and the driven cam are in rolling contact with a cam surface provided on the other of the drive cam and the driven cam.

[0095] In this example, the cam device 31 further has a plurality of rolling elements 40 that are supported by the driven cam 39 and are in rolling contact with a drive cam surface 52 provided on the drive cam 38, in addition to the drive cam 38 and the driven cam 39.

[0096] The drive cam 38 is supported with respect to the rotating member 10 so as to be capable of rotating with respect to the rotating member 10 and the input member 8 and incapable of axial displacement with respect to the rotating member 10. Specifically, as shown in FIG. 5 and the like, the drive cam 38 is supported by a cylindrical member 41, a radial bearing 42, and an angular ball bearing 43 so as to be capable of relative rotation with respect to the rotating member 10. In FIGS. 2 to 3(B), the illustration of the cylindrical member 41 and the angular ball bearing 43 is omitted.

[0097] The cylindrical member 41 has a cylindrical portion 44 and an outward flange portion 45 that bends radially outward from the end on the other axial side of the cylindrical portion 44. The cylindrical member 41 is supported and fixed to the fixed portion 14 by screwing or the like.

[0098] The radial bearing 42 has an inner ring 46 externally fitted and fixed to the end portion on the other axial side of the rotating member 10, an outer ring 47 internally fitted and fixed to the cylindrical portion 44 of the cylindrical member 41, and a plurality of rolling elements 48 rotatably arranged between the inner ring 46 and the outer ring 47. In the illustrated example, the radial bearing 42 is constituted by a double-row deep groove ball bearing using balls as the rolling elements 48. However, the radial bearing is not particularly limited as long as it enables relative rotation between the first member and the cam device and can support the axial biasing force by the elastic biasing mechanism. For example, it can also be constituted by a deep groove ball bearing, a radial angular ball bearing, or a radial cylindrical roller bearing.

[0099] The angular ball bearing 43 has an inner ring 49 externally fitted and fixed to the cylindrical portion 44 of the cylindrical member 41, an outer ring 50 internally fitted and fixed to the drive cam 38, and a plurality of balls 51 rotatably arranged between the inner ring 49 and the outer ring 50.

[0100] As shown in FIG. 12, the drive cam 38 has a drive cam surface 52 in which the same number of concave portions and convex portions are alternately arranged in the circumferential direction in the radially inner portion of the side surface on one axial side. The drive cam surface 52 is arranged in the order of a first bottom portion 52a, a gentle inclined surface portion 52b, a first flat surface portion 52c, an inclined surface portion 52d, a second bottom portion 52e, a first middle inclined surface portion 52f, a second flat surface portion 52g, and a second middle inclined surface portion 52h from the upper side to the lower side in FIGS. 15(A) to 15(D), and is repeated the number of times of the rolling elements 40 (three times in this example).

[0101] Among the drive cam surface 52, the first flat surface portion 52c and the second flat surface portion 52g are located on the most one side in the axial direction, that is, at the tip of the convex portion, and the first bottom portion 52a and the second bottom portion 52e are located on the most other side in the axial direction. The inclination angles of the first middle inclined surface portion 52f and the second middle inclined surface portion 52h with respect to the virtual plane P orthogonal to the central axis of the drive cam 38 are larger than those of the gentle inclined surface portion 52b with respect to the virtual plane P.

[0102] The inclination angle of the gently inclined surface portion 52b, and the inclination angles of the first moderately inclined surface portion 52f and the second moderately inclined surface portion 52h are all set to magnitudes such that the rolling element 40 can move either by rolling down or by riding up. In this example, the first moderately inclined surface portion 52f and the second moderately inclined surface portion 52h have opposite inclination directions and the same inclination angles as each other, but the inclination angles can also be made different from each other. Also, in this example, the inclination angle of the gently inclined surface portion 52b is made smaller than the inclination angles of the first moderately inclined surface portion 52f and the second moderately inclined surface portion 52h, but the inclination angle of the gently inclined surface portion 52b and the inclination angles of the first moderately inclined surface portion 52f and the second moderately inclined surface portion 52h can also be made the same as each other.

[0103] Note that the inclination angle of the inclined surface portion 52d with respect to the virtual plane P can be set to any magnitude as long as the rolling element 40 can ride up.

[0104] In this example, the drive cam 38 has, on its outer peripheral surface, wheel teeth 53 which are helical gears, and has, at a plurality of circumferential positions (three positions in the illustrated example) in the radial intermediate portion of one side surface in the axial direction, pin portions 54 that project toward one side in the axial direction.

[0105] The driven cam 39 is arranged around the rotating member 10 so as to be axially displaceable only. In this example, the driven cam 39 has a hollow circular plate shape and is supported so as to be axially displaceable with respect to the fixed portion 14. In this example, the driven cam 39 is supported so as to be axially displaceable with respect to the fixed portion 14 by spline-engaging a female spline portion 55 provided on the inner peripheral surface of the driven cam 39 with a male spline portion 56 provided on the outer peripheral surface of one axial side portion of the cylindrical portion 44 of the cylindrical member 41. However, the method of supporting the driven cam with respect to the fixed portion is not particularly limited as long as the driven cam can be supported with respect to the fixed portion so as to be axially displaceable only. For example, the driven cam can also be supported so as to be axially displaceable with respect to the fixed portion by key-engaging a convex portion provided on one of the driven cam and the fixed portion with a concave groove provided on the other.

[0106] As shown in FIG. 13, the driven cam 39 has rectangular holes 57 penetrating axially at a plurality of circumferential positions (three positions in the illustrated example) in the radial intermediate portion, and has substantially semi-circular plate-shaped support plate portions 58a and 58b protruding axially toward the other side from both radial sides of each of the rectangular holes 57. Among the support plate portions 58a and 58b, the radially outer support plate portion 58a is provided with a support hole 59 which is a circular hole penetrating in the radial direction, and the radially inner support plate portion 58b is provided with a support recess 60 having a circular opening on the radially outer surface.

[0107] In this example, the plurality of rolling elements 40 are constituted by three rolling elements 40. However, the plurality of rolling elements 40 can also be constituted by two or four or more rolling elements 40.

[0108] Each of the rolling elements 40 has a cylindrical shape and is rotatably supported on the support plate portions 58a and 58b via a cylindrical support shaft 68 and a plurality of rollers 69. That is, among the support shafts 68, the outer end portion in the radial direction centered on the central axis of the driven cam 39 is fitted and fixed in the support hole 59 of the radially outer support plate portion 58a, and among the support shafts 68, the inner end portion in the radial direction centered on the central axis of the driven cam 39 is fitted and fixed in the support recess 60 of the radially inner support plate portion 58b. The plurality of rollers 69 are rotatably sandwiched between the inner peripheral surface of the rolling element 40 and the outer peripheral surface of the axial intermediate portion of the support shaft 68. Thereby, the rolling element 40 is supported by the driven cam 39 so as to be able to freely rotate (autogenerate) about a rotation axis C facing in the radial direction centered on the central axis of the driven cam 39.

[0109] With the rolling element 40 supported by the driven cam 39, one axial side portion of the rolling element 40 is disposed inside the rectangular hole 57. Each of the rolling elements 40 has its outer peripheral surface in rolling contact with a drive cam surface 52 provided on the axial other side surface of the drive cam 38.

[0110] The cam device 31 rotationally drives the drive cam 38, and by increasing or decreasing the amount by which the rolling element 40 rides up from the first bottom 52a or the second bottom 52e of the drive cam surface 52, the driven cam 39 is axially moved, and the axial distance between the drive cam 38 and the driven cam 39, that is, the axial dimension of the cam device 31 is expanded or contracted.

[0111] The electric actuator 32 has a shift motor 70 and a speed reducer 71, and the shift motor 70 rotationally drives the drive cam 38 of the cam device 31 via the speed reducer 71.

[0112] In this example, the speed reducer 71 is constituted by a worm speed reducer. That is, the speed reducer 71 is formed by meshing worm teeth provided on the outer peripheral surface of a worm 72 connected to the output shaft of the shift motor 70 with wheel teeth 53 provided on the outer peripheral surface of the drive cam 38. The worm 72 is rotatably supported with respect to the fixed portion 14 by a pair of support bearings 73a and 73b. However, the speed reducer 71 can also be constituted by meshing spur gears or bevel gears provided on the output shaft of the electric motor with spur gears or bevel gears provided on the drive cam, or by passing a belt or a chain between the output shaft of the electric motor and the drive cam.

[0113] The electric friction clutch device 11 is configured to be switchable between a connection mode in which torque is transmitted between the first clutch member and the second clutch member by pressing the first friction plate 33 and the second friction plate 34 against each other based on expanding or contracting the axial dimension of the cam device 31, and a disconnection mode in which torque is not transmitted between the first clutch member and the second clutch member by releasing the force pressing the first friction plate 33 and the second friction plate against each other.

[0114] In this example, the drive cam 38 is rotationally driven by the electric actuator 32, and based on expanding the axial dimension of the cam device 31, that is, the axial interval between the drive cam 38 and the driven cam 39, the first friction plate 33 and the second friction plate 34 are pressed against each other, and based on reducing the axial dimension of the cam device 31, the force with which the first friction plate 33 and the second friction plate 34 are pressed against each other is released.

[0115] As an optional component, the electric friction clutch device 11 can further include an elastic biasing mechanism 30 provided between the rotating member 10 which is the first clutch member or the input member 8 which is the second clutch member and the friction engagement portion 29, and elastically biasing the first friction plate 33 and the second friction plate 34 in a direction to press against each other.

[0116] In this case, based on relatively displacing the driven cam 39 in a direction in which the axial interval from the drive cam 38 expands, the electric friction clutch device 11 presses the elastic biasing mechanism 30 by the driven cam 39 in a direction to release the force with which the first friction plate 33 and the second friction plate 34 are pressed against each other, and based on relatively displacing the driven cam 39 in a direction in which the axial interval from the drive cam 38 contracts, it is configured such that the elastic biasing mechanism 30 presses the first friction plate 33 and the second friction plate 34 in a direction to press against each other.

[0117] Alternatively, as an optional component, the electric friction clutch device 11 can further include an elastic biasing mechanism disposed between the friction engagement portion 29 and the driven cam 39 and elastically biasing the friction engagement portion 29 and the driven cam 39 in a direction to separate from each other.

[0118] In this case, the electric friction clutch device 11 presses the first friction plate 33 and the second friction plate 34 against each other in a direction to press them against each other based on relative displacement of the driven cam 39 in a direction in which the axial distance from the driving cam 38 increases, via the elastic biasing mechanism 30 by the driven cam 39, and is configured to release the force pressing the first friction plate 33 and the second friction plate 34 against each other based on relative displacement of the driven cam 39 in a direction in which the axial distance from the driving cam 38 decreases.

[0119] In this example, the electric friction clutch device 11 is provided between the rotating member 10 which is the first clutch member or the input member 8 which is the second clutch member and the friction engagement portion 29, and includes an elastic biasing mechanism 30 that elastically biases the first friction plate 33 and the second friction plate 34 in a direction to press them against each other.

[0120] In this example, the elastic biasing mechanism 30 has a piston 36 and an elastic member 37.

[0121] The piston 36 is supported so as to be axially displaceable with respect to the rotating member 10. The piston 36 is configured in a hollow circular plate shape and is supported so as to be axially displaceable with respect to the rotating member 10 around a portion between the small-diameter flange portion 18 and the flange portion 19 of the rotating member 10 in the axial direction. The piston 36 opposes the end face on the other axial side of the radially outer portion to the side face on the one axial side of the first friction plate 33 or the second friction plate 34 which is located on the most one axial side among the first friction plate 33 and the second friction plate 34.

[0122] The elastic member 37 is provided between the rotating member 10 and the piston 36. In this example, the elastic member 37 is sandwiched in an elastically compressed state between the side face on the other axial side of the small-diameter flange portion 18 of the rotating member 10 and the side face on the one axial side of the piston 36. That is, the elastic biasing mechanism 30 elastically biases the first friction plate 33 and the second friction plate 34 in a direction to press them against each other by pressing the first friction plate 33 or the second friction plate 34 on the most one axial side toward the other axial side via the piston 36 by the force with which the elastic member 37 tries to elastically recover.

[0123] The specific configuration of the elastic member is not particularly limited. In this example, the elastic member 37 is composed of at least one disc spring, and in the illustrated example, two disc springs. However, the elastic member can also be composed of other elastic members such as at least one coil spring.

[0124] The elastic biasing mechanism 30 of this example further includes a thrust bearing 61, a pressing member 62, and a preload applying means 65 between the driven cam 39 and the piston 36.

[0125] The thrust bearing 61 is provided between the pressing member 62 disposed opposite to the piston 36 and the driven cam 39 of the cam device 31. The thrust bearing 61 has a pair of race rings 63a, 63b and a plurality of rolling elements 64 rotatably disposed between the pair of race rings 63a, 63b. Of the pair of race rings 63a, 63b, the race ring 63b on the other axial side is supported and fixed to the driven cam 39.

[0126] The pressing member 62 has a cylindrical base portion 66 and a partial cylindrical portion 67 protruding axially on one side from a plurality of circumferential positions (three positions in the illustrated example) at one axial end of the base portion 66. At the other axial end of the base portion 66, the race ring 63a on the one axial side of the pair of race rings 63a, 63b of the thrust bearing 61 is supported and fixed. The partial cylindrical portion 67 is inserted into the through hole 20 of the rotating member 10, and the tip end portion (one axial end portion) of the partial cylindrical portion 67 faces the radial intermediate portion of the side surface on the other axial side of the piston 36.

[0127] The preloading means 65 is disposed between the pressing member 62 and the rotating member 10, and applies preload to the thrust bearing 61. The preloading means 65 is elastically compressed and held between the pressing member 62 and the side surface on the other axial side of the first annular portion 21 of the flange portion 19 constituting the rotating member 10. Thereby, as shown in FIG. 3(B), even when the piston 36 is pressed toward one axial side against the elastic restoring force of the elastic member 37, preload is applied to the thrust bearing 61, and the thrust bearing 61 is prevented from falling off between the elastic biasing mechanism 30 and the cam device 31. Note that the elastic force of the preloading means 65 is smaller than the elastic restoring force of the elastic member 37. The preloading means 65 can be constituted by, for example, an elastic member such as an elastomer like rubber, one or a plurality of disc springs, or one or a plurality of coil springs.

[0128] The electric friction clutch device 11 in this example includes, as an optional component, a return spring 35 that is disposed between the first friction plate 33 and the second friction plate 34 and is elastically biased in a direction to increase the distance between the first friction plate 33 and the second friction plate 34. Thereby, when the force pressing the first friction plate 33 and the second friction plate 34 against each other is released, the first friction plate 33 and the second friction plate 34 can be surely separated. The elastic force of the return spring 35 is smaller than the elastic restoring force of the elastic member 37 of the elastic biasing mechanism 30.

[0129] In this example, the electric friction clutch device 11 is configured such that the drive cam 38 is rotationally driven by the electric actuator 32, the axial dimension of the cam device 31 is expanded and contracted, and the piston 36 of the elastic biasing mechanism 30 is axially displaced relative to the rotating member 10, whereby the electric friction clutch device 11 can be switched between a disconnection mode in which torque is not transmitted between the rotating member 10 and the input member 8 and a connection mode in which torque is transmitted.

[0130] First, when switching the electric friction clutch device 11 to the disengagement mode in which torque is not transmitted between the rotating member 10 and the input member 8, by rotationally driving the drive cam 38 with the electric actuator 32, as shown in FIGS. 15(B) and 15(D), the rolling element 40 is positioned on the first flat surface portion 52c or the second flat surface portion 52g of the drive cam surface 52, or the amount of riding up on the gentle slope surface portion 52b, the slope surface portion 52d, the first middle slope surface portion 52f, or the second middle slope surface portion 52h is increased.

[0131] Thereby, by moving the driven cam 39 in the axial direction one side which is the direction in which the axial direction interval with the drive cam 38 expands, via the thrust bearing 61 and the pressing member 62, the piston 36 of the elastic biasing mechanism 30 is pressed toward the axial direction one side, and the elastic member 37 is elastically compressed. When the elastic member 37 is elastically compressed, the force for pressing the first friction plate 33 and the second friction plate 34 against each other decreases and finally disappears. As a result, due to the action of the return spring 35, the interval between the first friction plate 33 and the second friction plate 34 expands, and the friction engagement portion 29 is disengaged, whereby the electric friction clutch device 11 is switched to the disengagement mode.

[0132] On the other hand, when switching the electric friction clutch device 11 to the connection mode in which torque is transmitted between the rotating member 10 and the input member 8, by rotationally driving the drive cam 38 with the electric actuator 32, as shown in FIGS. 15(A) and 15(C), the rolling element 40 is positioned on the first bottom portion 52a or the second bottom portion 52e of the drive cam surface 52, or the amount of riding up on the gentle slope surface portion 52b, the slope surface portion 52d, the first middle slope surface portion 52f, or the second middle slope surface portion 52h is decreased.

[0133] By moving the driven cam 39 axially toward the other axial side, which is the direction in which the axial distance from the driving cam 38 decreases, the force pressing the piston 36 of the elastic biasing mechanism 30 axially toward one side is decreased. For this reason, mainly due to the elastic restoring force of the first friction plate 33 and the elastic member 37, the piston 36, the thrust bearing 61, and the pressing member 62 are pressed axially toward the other side, and the first friction plate 33 or the second friction plate 34 on the most axially one side is pressed axially toward the other side by the piston 36. As a result, the first friction plate 33 and the second friction plate 34 are pressed against each other, and when the friction engagement portion 29 is connected, the electric friction clutch device 11 switches to the connected mode.

[0134] In this example, when maintaining the disconnection mode of the electric friction clutch device 11, it is necessary to continue energizing the shift motor 70 in order to prevent the piston 36 from moving axially toward the other side due to the elastic force of the elastic member 37. On the other hand, when maintaining the electric friction clutch device 11 in the connected mode, the first friction plate 33 and the second friction plate 34 can be pressed against each other by pressing the piston 36 axially toward the other side due to the elastic force of the elastic member 37. Therefore, when maintaining the electric friction clutch device 11 in the connected mode, it is not necessary to continue energizing the shift motor 70. That is, the electric friction clutch device 11 of this example is configured by a normally-closed type clutch device.

[0135] The rotational transmission state switching device 12 includes a first member 74 having engagement recesses 77 at a plurality of locations in the circumferential direction, a second member 75 arranged coaxially with the first member 74, and a mode select member 76 that rotates or is displaced axially as the driving cam 38 rotates.

[0136] One of the first member 74 and the second member 75 is connected to the rotating member 10 so as to rotate integrally therewith, or is constituted by the rotating member 10 itself. The other member of the first member 74 and the second member 75 is supported so as not to be relatively rotatable with respect to the fixed portion 14 that does not rotate even during use. In this example, the first member 74 is connected to the rotating member 10 so as to rotate integrally therewith, and the second member 75 is supported so as not to be relatively rotatable with respect to the fixed portion 14 that does not rotate even during use. Further, the mode select member 76 rotates as the drive cam 38 rotates.

[0137] The rotation transmission state switching device 12 has a free mode in which rotation of the first member 74 with respect to the second member 75 is allowed regardless of the relative rotation direction between the first member 74 and the second member 75, which is switched based on the rotation or axial displacement of the mode select member 76, and a lock mode in which relative rotation between the first member 74 and the second member 75 is blocked regardless of the relative rotation direction between the first member 74 and the second member 75.

[0138] The rotation transmission state switching device 12 is configured to be switched to the free mode by disengaging the engaging member from at least one of the first member 74 and the second member 75 based on the rotation or axial displacement of the mode select member 76, and to be switched to the lock mode by engaging the engaging member with both the first member 74 and the second member 75.

[0139] In addition to the free mode and the lock mode, the rotation transmission state switching device 12 can have a one-way clutch mode in which only rotation of the first member 74 in a predetermined direction with respect to the second member 75 is allowed. The rotation transmission state switching device 12 in this example has a one-way clutch mode. Specifically, the rotation transmission state switching device 12 is switchable between the free mode, the lock mode, and the one-way clutch mode based on the rotation of the mode select member 76.

[0140] When the rotation transmission state switching device 12 has a one-way clutch mode, the engaging member includes a first engaging member that is stretched between the first member 74 and the second member 75, allows rotation of the one member in a predetermined direction with respect to the other member, and blocks rotation in a direction opposite to the predetermined direction; and a second engaging member that is stretched between the first member 74 and the second member 75, blocks rotation of the one member in a direction opposite to the predetermined direction with respect to the other member, and allows rotation in the predetermined direction.

[0141] The rotation transmission state switching device 12 can be switched to a free mode by disengaging the first engaging member from at least one of the first member 74 and the second member 75 and disengaging the second engaging member from at least one of the first member 74 and the second member 75. The rotation transmission state switching device 12 can be switched to a lock mode by engaging both the first engaging member and the second engaging member with the first member 74 and the second member 75. Further, the rotation transmission state switching device 12 can be switched to a one-way clutch mode by engaging the first engaging member with both the first member 74 and the second member 75 and disengaging the second engaging member from at least one of the first member 74 and the second member 75.

[0142] In this example, the first member 74 has engaging recesses 77 at a plurality of circumferential positions on the outer peripheral surface. That is, the first member 74 has a gear-shaped uneven portion 79 in which the engaging recesses 77 and the convex portions 78 are alternately arranged in the circumferential direction on the outer peripheral surface.

[0143] Further, the first member 74 has an outer diameter side uneven engagement portion 80 in which concave and convex portions are alternately arranged in the circumferential direction on the inner peripheral surface. The first member 74 is supported so as not to be able to rotate relative to the rotating member 10 by engaging the outer diameter side uneven engagement portion 80 with an inner diameter side uneven engagement portion 81 provided on the outer peripheral surface of the second cylindrical portion 24 of the rotating member 10. That is, the first member 74 rotates integrally with the rotating member 10.

[0144] The second member 75 is supported coaxially with the first member 74 around the first member 74 and is capable of relative rotation with respect to the first member 74. That is, the inner peripheral surface of the second member 75 faces the outer peripheral surface of the first member 74, that is, the tip surface of the convex portion 78, with a gap therebetween. The second member 75 has an inner diameter side concavo-convex engagement portion 82 on its outer peripheral surface, in which concave portions and convex portions are alternately arranged in the circumferential direction. The second member 75 is supported so as to be unable to rotate relative to the fixed portion 14 by engaging the inner diameter side concavo-convex engagement portion 82 with an outer diameter side concavo-convex engagement portion provided on the inner peripheral surface of the fixed portion 14. That is, the second member 75 does not rotate even when the two-speed transmission 3 is in use.

[0145] The second member 75 includes a base portion 83 having a rectangular cross-sectional shape, and a cylindrical portion 84 that projects over the entire circumference from the radially outer end of the side surface on one axial side of the base portion 83 toward one axial side.

[0146] The base portion 83 has a plurality (six in the illustrated example) of first holding recesses 85 and second holding recesses 86 that are alternately arranged in the circumferential direction.

[0147] Each of the first holding recesses 85 opens to the inner peripheral surface of the base portion 83 and the side surface on the other axial side. Each of the first holding recesses 85 includes a spring holding portion 87a and a pedestal portion 88a. The spring holding portion 87a has a substantially rectangular opening shape in which the major axis is arranged in a direction extending radially outward as it goes toward one circumferential side (the clockwise front side in FIGS. 18 to 20) when viewed from the other axial side. The pedestal portion 88a has a substantially circular opening shape when viewed from the other axial side and is arranged adjacent to the other circumferential side (the clockwise rear side in FIGS. 18 to 20) of the spring holding portion 87a.

[0148] Each second holding recess 86 opens to the inner circumferential surface of the base portion 83 and the side surface on the other axial side. Each second holding recess 86 has a shape symmetrical to the first holding recess 85 with respect to the virtual plane including the central axis of the second member 75 when viewed from the other axial side. That is, each second holding recess 86 includes a spring holding portion 87b and a pedestal portion 88b. The spring holding portion 87b has a substantially rectangular opening shape in which the major axis is arranged in a direction extending radially outward as it goes toward the other circumferential side when viewed from the other axial side. The pedestal portion 88b has a substantially circular opening shape when viewed from the other axial side and is arranged adjacent to the one circumferential side of the spring holding portion 87a.

[0149] The rotation transmission state switching device 12 in this example includes a first claw member 89 as a first engaging member and a second claw member 90 as a second engaging member, and a first claw biasing member 91 and a second claw biasing member 92. In this example, the rotation transmission state switching device 12 has a plurality of each of the first claw member 89 and the second claw member 90, and the same number of each of the first claw biasing member 91 and the second claw biasing member 92.

[0150] Each first claw member 89 includes a first base portion 93 and a first engaging claw 94.

[0151] The first base portion 93 is configured in a substantially cylindrical shape and is supported (pivotally supported) on the pedestal portion 88a of the first holding recess 85 so as to be able to swing about a pivot axis parallel to the central axis of the second member 75.

[0152] The first engaging claw 94 is configured in a substantially flat plate shape and extends from the first base portion 93 toward the one circumferential side. The first engaging claw 94 opposes (engages) the outer circumferential surface of the annular convex portion 95 of the mode select member 76 at the other axial side portion, and engages (enables engagement and disengagement with the engaging recess 77) the uneven portion 79 of the first member 74 at the one axial side portion.

[0153] Each second claw member 90 includes a second base portion 96 and a second engaging claw 97.

[0154] The second base portion 96 is configured in a substantially cylindrical shape and is supported on the pedestal portion 88b of the second holding recess 86 so as to be capable of swinging about a pivot axis parallel to the central axis of the second member 75.

[0155] The second engaging claw 97 is configured in a substantially flat plate shape and extends from the second base portion 96 toward the other side in the circumferential direction. The second engaging claw 97 has the other portion on the other side in the axial direction facing the outer peripheral surface of the annular convex portion 95 of the mode select member 76, and has the one portion on the one side in the axial direction facing the concavo-convex portion 79 of the first member 74.

[0156] The first claw biasing member 91 elastically biases the first engaging claw 94 of the first claw member 89 in a direction to engage with the engaging recess 77 of the first member 74. That is, the first claw biasing member 91 applies a biasing force to the first claw member 89 in a direction in which the first claw member 89 swings in the clockwise direction in FIG. 19 about the central axis (pivot axis) of the first base portion 93. Specifically, the first claw biasing member 91 is constituted by an elastic member such as a coil spring, and is held in an elastically compressed state between the bottom surface (the surface facing the radially inner side) of the spring holding portion 87a of the first holding recess 85 and the radially outer surface of the first engaging claw 94.

[0157] The second claw biasing member 92 elastically biases the second engaging claw 97 of the second claw member 90 in a direction to engage with the engaging recess 77 of the first member 74. That is, the second claw biasing member 92 applies a biasing force to the second claw member 90 in a direction in which the second claw member 90 swings in the counterclockwise direction in FIG. 19 about the central axis of the second base portion 96. Specifically, the second claw biasing member 92 is constituted by an elastic member such as a coil spring, and is held in an elastically compressed state between the bottom surface (the surface facing the radially inner side) of the spring holding portion 87b of the second holding recess 86 and the radially outer surface of the second engaging claw 97.

[0158] As shown in FIG. 17, the mode select member 76 includes a substantially annular plate-shaped base portion 98 and an annular convex portion 95 that projects over the entire circumference from the radially intermediate portion of the side surface on the other side in the axial direction of the base portion 98 toward the other side in the axial direction.

[0159] The base portion 98 has plate-side engagement holes 99 at a plurality of circumferentially equally spaced positions in the radial intermediate portion of the side surface on the other axial side (three positions in the illustrated example). The end portion on one axial side of the pin portion 54 is snugly fitted (engaged) into each of the plate-side engagement holes 99 without rattling. That is, the mode selection member 76 rotates integrally (in the same direction at the same speed) with the drive cam 38.

[0160] The annular convex portion 95 has protruding portions 100 protruding radially outward at a plurality of circumferentially spaced positions on the outer peripheral surface. That is, the annular convex portion 95 has a gear-shaped uneven portion 101 formed by alternately arranging the protruding portions 100 and the concave portions on the outer peripheral surface in the circumferential direction.

[0161] The first member 74, the second member 75, and the mode selection member 76 are combined by the lid body 102 and the retaining ring 103 so as to be relatively rotatable and incapable of relative displacement in the axial direction (so as not to be inadvertently separated in the axial direction), thereby constituting the rotation transmission state switching device 12.

[0162] Specifically, with the first member 74 disposed radially inside the one-axial-side portion of the base portion 83 of the second member 75, an annular lid body 102 is supported and fixed by screwing to the side surface on the one-axial side of the second member 75, and the side surface on the other axial side of the radially inner portion of the lid body 102 is opposed to the side surface on the one-axial side of the first member 74. Thereby, the displacement of the first member 74 toward the one-axial side with respect to the second member 75 is blocked.

[0163] The annular convex portion 95 of the mode selection member 76 is disposed radially inside the other-axial-side portion of the base portion 83 of the second member 75, the tip surface (the side surface on the one-axial side) of the annular convex portion 95 is in sliding contact or closely opposed to the side surface on the other axial side of the first member 74, and the side surface on the one-axial side of the radially outer portion of the base portion 98 is in sliding contact or closely opposed to the side surface on the other axial side of the base portion 83 of the second member 75. In this state, the retaining ring 103 is locked to the end portion on the other axial side of the inner peripheral surface of the cylindrical portion 84 of the second member 75. Thereby, the displacement of the first member 74 and the mode selection member 76 toward the other axial side with respect to the second member 75 is blocked.

[0164] The rotation transmission state switching device 12 of this example is configured to be able to switch between a free mode, a lock mode, and a one-way clutch mode by switching the engagement state between the first engaging claw 94 of the first claw member 89 and the engaging recess 77 of the first member 74, and the engagement state between the second engaging claw 97 of the second claw member 90 and the engaging recess 77 based on the rotation of the mode select member 76.

[0165] <Free mode> In the free mode, the circumferential phase of the mode select member 76 with respect to the second member 75 is adjusted. As shown in Fig. 20(A), by the protruding portion 100, the first engaging claw 94 is pushed radially outward against the elastic force of the first claw biasing member 91, and the second engaging claw 97 is pushed radially outward against the elastic force of the second claw biasing member 92. As a result, the engagement between the engaging recess 77 of the first member 74 and the first engaging claw 94 and the second engaging claw 97 is disengaged. In this state, regardless of the relative rotation direction between the first member 74 and the second member 75, the rotation of the first member 74 with respect to the second member 75 is permitted. That is, regardless of the rotation direction of the first member 74, the rotation of the first member 74 with respect to the fixed portion 14 is permitted.

[0166] <Lock mode> In the lock mode, the circumferential phase of the mode select member 76 with respect to the second member 75 is adjusted. As shown in Fig. 20(B), the protruding portion 100 is positioned at a portion circumferentially disengaged from the first engaging claw 94 of the first claw member 89 and the second engaging claw 97 of the second claw member 90. That is, in the circumferential direction, the phase of the recess among the concave-convex portions 101 is made to coincide with the first engaging claw 94 and the second engaging claw 97. As a result, the engaging recess 77 of the first member 74 engages with the first engaging claw 94 and the second engaging claw 97. In this state, regardless of the relative rotation direction between the first member 74 and the second member 75, the rotation of the first member 74 with respect to the second member 75 is blocked. That is, regardless of the rotation direction of the first member 74, the rotation of the first member 74 with respect to the fixed portion 14 is blocked.

[0167] <One-way clutch mode> In the one-way clutch mode, the circumferential phase of the mode select member 76 with respect to the second member 75 is adjusted. As shown in FIG. 20(C), only the second engagement claw 97 is pushed radially outward against the elastic force of the second claw biasing member 92 by the protrusion 100. As a result, the engagement recess 77 of the first member 74 engages with the first engagement claw 94, and the engagement between the engagement recess 77 and the second engagement claw 97 is disengaged. In this state, only the rotation of the first member 74 in the predetermined direction (clockwise direction in FIG. 20(C)) with respect to the second member 75 is allowed, and the rotation in the direction opposite to the predetermined direction (counterclockwise direction in FIG. 20(C)) is blocked.

[0168] That is, when the first member 74 attempts to rotate in the predetermined direction with respect to the second member 75, the first engagement claw 94 is pushed radially outward against the elastic force of the first claw biasing member 91 by the convex portion 78 of the concavo-convex portion 79. As a result, the rotation of the first member 74 in the predetermined direction is allowed. On the other hand, when the first member 74 attempts to rotate in the direction opposite to the predetermined direction with respect to the second member 75, the engagement between the engagement recess 77 and the first engagement claw 94 blocks the rotation of the first member 74 in the direction opposite to the predetermined direction. In short, the rotation transmission state switching device 12 operates as a ratchet type one-way clutch.

[0169] Note that the predetermined direction coincides with the forward rotation direction of the input member 8. The forward rotation direction of the input member 8 refers to the rotation direction of the input member 8 when the vehicle is moving forward.

[0170] The two-speed transmission 3 is configured to be able to switch between a high reduction ratio mode in which the reduction ratio between the input member 8 and the output member 9 is large and a low reduction ratio mode in which the reduction ratio between the input member 8 and the output member 9 is small by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12.

[0171] The two-speed transmission 3 of this example further includes a planetary gear mechanism 13 as an optional component. That is, the two-speed transmission 3 of this example can switch between a high reduction ratio mode and a low reduction ratio mode by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12, thereby switching the transmission path of the torque transmitted through the planetary gear mechanism 13.

[0172] The planetary gear mechanism 13 includes a sun gear 104, a ring gear 105, a carrier 106, and a plurality of planetary gears 107.

[0173] The ring gear 105 is arranged coaxially with the sun gear 104 around the sun gear 104.

[0174] The carrier 106 is supported coaxially with the sun gear 104 and the ring gear 105 and is capable of relative rotation with respect to the sun gear 104 and the ring gear 105.

[0175] The plurality of planetary gears 107 mesh with the sun gear 104 and the ring gear 105 and are supported by the carrier 106 so as to be capable of rotating (self-rotating) about their own central axes.

[0176] The plurality of planetary gears 107 can each be constituted by a planetary gear that meshes with both the sun gear 104 and the ring gear 105. That is, the planetary gear mechanism 13 can be constituted by a single pinion type planetary gear mechanism. Alternatively, the plurality of planetary gears 107 can also have a first planetary gear that meshes with the sun gear 104 and a second planetary gear that meshes with the ring gear and also meshes with the first planetary gear. That is, the planetary gear mechanism 13 can be constituted by a double pinion type planetary gear mechanism.

[0177] In the two-speed transmission 3, by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device, the reduction ratio between the input member 8 and the output member 9 can be switched between a high and a low stage. The input member 8, the output member 9, the first friction plate 33 and the second friction plate 34 of the electric friction clutch device 11, and the first member 74 and the second member 75 of the rotation transmission state switching device 12 are connected to the sun gear 104, the ring gear 105, the carrier 106, or the fixed portion 14.

[0178] Specifically, an input element, which is any one of the sun gear 104, the ring gear 105, and the carrier 106, is connected to the input member 8 so as to rotate integrally with the input member 8. An output element, which is any one of the sun gear 104, the ring gear 105, and the carrier 106 and is different from the input element, is connected to the output member 9 so as to rotate integrally with the output member 9. Further, a rotation element, which is the remaining element among the sun gear 104, the ring gear 105, and the carrier 106 excluding the input element and the output element, is connected to the rotating member 10 so as to rotate integrally with the rotating member 10.

[0179] For example, the ring gear 105 can be connected to the input member 8 so as to rotate integrally with the input member 8, the carrier 106 can be connected to the output member 9 so as to rotate integrally with the output member 9, and the sun gear 104 can be connected to the rotating member 10 so as to rotate integrally with the rotating member 10.

[0180] Alternatively, the sun gear 104 can be connected to the input member 8 so as to rotate integrally with the input member 8, the carrier 106 can be connected to the output member 9 so as to rotate integrally with the output member 9, and the ring gear 105 can be connected to the rotating member 10 so as to rotate integrally with the rotating member 10.

[0181] Alternatively, the sun gear 104 can be connected to the input member 8 so as to rotate integrally with the input member 8, the ring gear 105 can be connected to the output member 9 so as to rotate integrally with the output member 9, and the carrier 106 can be connected to the rotating member 10 so as to rotate integrally with the rotating member 10.

[0182] In this example, the ring gear 105 is connected to the input member 8 so as to rotate integrally with the input member 8, the carrier 106 is connected to the output member 9 so as to rotate integrally with the output member 9, and the sun gear 104 is connected to the rotating member 10 so as to rotate integrally with the rotating member 10.

[0183] More specifically, the sun gear 104 is provided at one end of the rotating member 10 in the axial direction.

[0184] The ring gear 105 is provided at the intermediate portion of the input member 8 in the axial direction.

[0185] The carrier 106 is integrally formed with the output member 9.

[0186] Also, each of the plurality of planetary gears 107 meshes with both the sun gear 104 and the ring gear 105, and is supported by the carrier 106 so as to be able to rotate (revolve) about its own central axis. That is, in this example, the planetary gear mechanism 13 is constituted by a single pinion type planetary gear mechanism.

[0187] The torque transmission mechanism 4 transmits torque between the output member 9 and the drive wheels 108.

[0188] In this example, the torque transmission mechanism 4 is constituted by a differential device that distributes the rotational torque of the output member 9 to a pair of drive wheels 108. By meshing the output gear 17 of the output member 9 with the ring gear 117 of the differential device that constitutes the torque transmission mechanism 4, torque can be transmitted between the output member 9 and the drive wheels 108.

[0189] The friction brake device 5 is disposed between the output member 9 and the drive wheel 108 to brake the rotation of the drive wheel 108.

[0190] In this example, the friction brake device 5 is configured to brake the rotation of the drive wheel 108 by pressing a friction member such as a pad or a shoe against a rotating body 110 for braking, such as a rotor or a drum, which is supported and fixed to the drive shaft 109 of the differential device that constitutes the torque transmission mechanism 4.

[0191] The control device 6 has a reduction ratio switching function and a cooperative control function.

[0192] In this example, the control device 6 is configured to control the drive motor 2, the two-speed transmission 3, and the friction brake device 5 based on signals from various sensors such as an accelerator opening sensor 111 that detects the operation amount of the accelerator pedal, an input rotation sensor 112 that detects the rotation speed of the motor output shaft 7, and an output rotation sensor 113 that detects the rotation speed of the drive wheel 108, in order to realize the reduction ratio switching function and the cooperative control function.

[0193]

[0194] First, the reduction ratio switching function of the control device 6 will be described.

[0195] ​The reduction ratio switching function switches the two-speed transmission 3 between a high reduction ratio mode with a large reduction ratio between the input member 8 and the output member 9 and a low reduction ratio mode with a small reduction ratio between the input member 8 and the output member 9 by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12 based on driving the drive cam 38 to rotate by the electric actuator 32. In the drive device 1 for an electric vehicle in this example, the control device 6 controls the electric actuator 32 by the TCU 114 based on a command from the VCU 116, and executes the reduction ratio switching function by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12.

[0196] <Low reduction ratio mode> To switch the two-speed transmission 3 to the low reduction ratio mode, switch the electric friction clutch device 11 to the connected mode and switch the rotation transmission state switching device 12 to the free mode.

[0197] Specifically, the drive cam 38 is rotated by the electric actuator 32, and based on expanding the axial dimension of the cam device 31, the electric friction clutch device 11 is switched to the connected mode. As a result, the input member 8 and the rotating member 10 rotate integrally, and the sun gear 104 and the ring gear 105 rotate integrally.

[0198] Simultaneously with switching the electric friction clutch device 11 to the connected mode, based on adjusting the phase of the mode select member 76 with respect to the circumferential direction of the second member 75 by the rotation of the drive cam 38, the rotation transmission state switching device 12 is switched to the free mode in which the rotation of the first member 74 with respect to the second member 75 is permitted regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, the rotation of the rotating member 10 with respect to the fixed portion 14 is permitted, and the rotation of the sun gear 104 is permitted.

[0199] In the low reduction ratio mode, the rotational directions and speeds of the sun gear 104, the ring gear 105, and the carrier 106 are the same, and the entire planetary gear mechanism 13 rotates integrally, which is a so-called mounted state. Therefore, the rotational torque of the input member 8 is transmitted in the order of the input member 8, the carrier 106, and the output member 9 and taken out from the output member 9, as shown by the thick line in Fig. 3(A).

[0200] <High reduction ratio mode> To switch the two-speed transmission 3 to the high reduction ratio mode, the electric friction clutch device 11 is switched to the disengagement mode, and the rotation transmission state switching device 12 is switched to the lock mode.

[0201] Specifically, the drive cam 38 is rotated by the electric actuator 32, and based on reducing the axial dimension of the cam device 31, the electric friction clutch device 11 is switched to the disengagement mode. As a result, the input member 8 and the rotating member 10 rotate relative to each other, and the sun gear 104 and the ring gear 105 can rotate relative to each other.

[0202] Simultaneously with switching the electric friction clutch device 11 to the disengagement mode, due to the rotation of the drive cam 38, the rotation transmission state switching device 12 is switched to the lock mode in which the rotation of the first member 74 relative to the second member 75 is blocked regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, the rotation of the rotating member 10 relative to the fixed portion 14 is blocked, and the rotation of the sun gear 104 is blocked.

[0203] In the high reduction ratio mode, the rotational torque of the input member 8 is transmitted in the order of the input member 8, the ring gear 105, the self-rotation of the planetary gear 107, the revolution of the planetary gear 107 based on the meshing with the sun gear 104, the carrier 106, and the output member 9 and taken out from the output member 9, as shown by the thick line in Fig. 3(B). The reduction ratio between the input member 8 and the output member 9 in the high reduction ratio mode is determined by the gear ratio between the ring gear 105 and the sun gear 104 (the number of teeth of the ring gear 105 / the number of teeth of the sun gear 104).

[0204] In the drive device 1 for an electric vehicle of this example, based on rotating one drive cam 38 by one electric actuator 32, by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12, the reduction ratio between the input member 8 and the output member 9 can be switched between two levels of high and low. Specifically, for example, when the power input to the input member 8 is in the region of low speed and high torque, the two-speed transmission 3 is switched to the high reduction ratio mode, and when it is in the region of high speed and low torque, it is switched to the low reduction ratio mode. Therefore, the acceleration performance and high-speed performance when an electric vehicle or a hybrid vehicle is running with only an electric motor as a drive source are such that the left side portion of the solid line a in FIG. 36 from the point P and the right side portion of the chain line b from the point P are continuous, and it can be made close to a gasoline engine vehicle shown by the broken line c in FIG. 36.

[0205] In the drive device 1 for an electric vehicle of this example, a hydraulic system for controlling a friction engagement device such as a clutch or a brake is not required. Therefore, in an electric vehicle or a hybrid vehicle, the system can be simplified, the cost can be reduced, and the power consumption performance can be improved.

[0206] In the drive device 1 for an electric vehicle of the present disclosure, the two-speed transmission 3 can have a reduction ratio switching mode for smoothly switching from the high reduction ratio mode during normal forward running (power running) to the low reduction ratio mode. Additionally or alternatively, the two-speed transmission 3 can have a neutral mode in which torque is not transmitted between the input member 8 and the output member 9, and / or a parking mode in which the rotation of the output member 9 is locked. In this example, the two-speed transmission 3 has, in addition to the low reduction ratio mode and the high reduction ratio mode, a reduction ratio switching mode, a neutral mode, and a parking mode.

[0207] <Reduction ratio switching mode> When the switching from the high reduction ratio mode to the low reduction ratio mode of the two-speed transmission 3 is started during normal forward running of the vehicle, first, based on adjusting the phase of the mode selection member 76 with respect to the second member 75 in the circumferential direction, as shown in FIG. 20(C), the protruding portion 100 pushes only the second engaging claw 97 radially outward against the elastic force of the second claw biasing member 92. As a result, only the first engaging claw 94 engages with the engaging recess 77 of the first member 74, and the rotation transmission state switching device 12 switches to the one-way clutch mode that allows only the rotation of the first member 74 with respect to the second member 75 in the predetermined direction (the predetermined direction in FIG. 20(C)) and blocks the rotation in the direction opposite to the predetermined direction.

[0208] Simultaneously with the rotation transmission state switching device 12 switching to the one-way clutch mode, or after switching to the one-way clutch mode, the electric friction clutch device 11 starts to switch from the disconnection mode to the connection mode. During the switching of the electric friction clutch device 11 from the disconnection mode to the connection mode, based on the rotation of the drive cam 38, as shown in the order of FIGS. 15(B) and 15(A), the rolling element 40 descends along the gently inclined surface portion 52b of the drive cam surface 52. Then, as the amount of the rolling element 40 rising from the first bottom portion 52a of the drive cam surface 52 gradually decreases, the force with which the first friction plate 33 and the second friction plate 34 press against each other gradually increases (the fastening force F of the friction engagement portion 29 gradually increases). At this time, the input member 8 rotates while sliding (while being in sliding contact) the axially both side surfaces of the second friction plate 34 with respect to the axially both side surfaces of the first friction plate 33.

[0209] During the rotation of the input member 8 in the forward rotation direction, when the fastening force F of the friction engagement portion 29 gradually increases, the torque applied to the second member 75 of the rotation transmission state switching device 12 in the direction opposite to the predetermined direction gradually decreases. At this time, since the rotation transmission state switching device 12 is switched to the one-way clutch mode, even if torque is applied to the second member 75 in the direction opposite to the predetermined direction, the second member 75 does not rotate. After the torque applied to the second member 75 in the direction opposite to the predetermined direction gradually decreases to zero and the direction of the torque applied to the second member 75 reverses (torque in the predetermined direction is applied to the second member 75), at that moment, the rotation of the second member 75 in the predetermined direction is permitted.

[0210] <Neutral mode> To switch the two-speed transmission 3 to the neutral mode, the electric friction clutch device 11 is switched to the disengagement mode, and the rotation transmission state switching device 12 is switched to the free mode.

[0211] For this purpose, based on rotating the drive cam 38 by the electric actuator 32, the rolling element 40 is positioned on the second flat surface portion 52g of the drive cam surface 52, and the driven cam 39 is displaced in the direction in which the axial distance from the drive cam 38 expands (one axial side). As a result, the piston 36 of the elastic biasing mechanism 30 is pressed toward one axial side via the thrust bearing 61 and the pressing member 62, thereby elastically compressing the elastic member 37 and losing the force that presses the first friction plate 33 and the second friction plate 34 against each other. Then, due to the action of the return spring 35, the distance between the first friction plate 33 and the second friction plate 34 expands, and the friction engagement portion 29 is disengaged, so that the electric friction clutch device 11 is switched to the disengagement mode. As a result, the input member 8 and the rotating member 10 become relatively rotatable, and the sun gear 104 and the ring gear 105 become relatively rotatable.

[0212] When the electric friction clutch device 11 is switched to the connection mode and, based on adjusting the phase of the mode selection member 76 with respect to the circumferential direction of the second member 75, as shown in FIG. 20(A), the protruding portion 100 pushes up the first engagement claw 94 radially outward and pushes up the second engagement claw 97 radially outward. As a result, the engagement between the engagement recess 77 of the first member 74 and the first engagement claw 94 and the second engagement claw 97 is disengaged, and the rotation transmission state switching device 12 switches to the free mode in which the rotation of the first member 74 with respect to the second member 75 is allowed regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, the rotation of the rotating member 10 with respect to the fixed portion 14 is allowed, and the rotation of the sun gear 104 is allowed.

[0213] In such a neutral mode, the input member 8 and the output member 9 rotate freely with respect to each other, and torque is not transmitted between the input member 8 and the output member 9.

[0214] <Parking lock mode> To switch the two-speed transmission 3 to the parking lock mode, the electric friction clutch device 11 is switched to the connection mode, and the rotation transmission state switching device 12 is switched to the lock mode.

[0215] For this purpose, based on rotating the drive cam 38 by the electric actuator 32, the rolling element 40 is positioned at the second bottom portion 52e of the drive cam surface 52, and the driven cam 39 is displaced in a direction in which the axial distance from the drive cam 38 is reduced (the other axial side). As a result, the force for pressing the piston 36 of the elastic biasing mechanism 30 toward one axial side is lost. Then, mainly due to the elastic restoring forces of the first friction plate 33 and the elastic member 37, the piston 36, the thrust bearing 61, and the pressing member 62 are pressed toward the other axial side, and the piston 36 presses the first friction plate 33 or the second friction plate 34 on the most one axial side toward the other axial side.

[0216] As a result, the first friction plate 33 and the second friction plate 34 are pressed against each other, and when the friction engagement portion 29 is connected, the electric friction clutch device 11 switches to the connection mode. As a result, the rotation of the input member 8 with respect to the rotating member 10 is blocked, and the rotation of the ring gear 105 with respect to the sun gear 104 is blocked.

[0217] Simultaneously with switching the electric friction clutch device 11 to the connection mode, based on adjusting the phase in the circumferential direction of the mode select member 76 with respect to the second member 75, as shown in FIG. 20(B), the protruding portion 100 is positioned at a portion deviated in the circumferential direction from the first engagement claw 94 and the second engagement claw 97. As a result, the engagement concave portion 77 of the first member 74 engages with the first engagement claw 94 and the second engagement claw 97, and the rotation transmission state switching device 12 switches to the lock mode in which the rotation of the first member 74 with respect to the second member 75 is blocked regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, the rotation of the rotating member 10 with respect to the fixed portion 14 is blocked, and the rotation of the sun gear 104 is blocked.

[0218] In such a parking lock mode, the rotations of the input member 8 and the output member 9 are locked.

[0219] The drive device 1 for an electric vehicle in this example is configured to control the output torque and the rotational speed R of the drive motor 2 and the rotational speed (rotation amount) of the shift motor 70 in order to prevent the rotational torque of the output member 9 from changing discontinuously (suddenly) and to prevent the occurrence of a shift shock when switching from the high reduction ratio mode to the low reduction ratio mode during normal forward running. An example of this control will be described with reference to FIGS. 26 and 27. The following example is an example in which the rotational torque of the output member 9 is maintained substantially constant before and after switching from the high reduction ratio mode to the low reduction ratio mode. s The rotational speed of the shift motor 70 is controlled. An example of this control will be described with reference to FIGS. 26 and 27. The following example is an example in which the rotational torque of the output member 9 is maintained substantially constant before and after switching from the high reduction ratio mode to the low reduction ratio mode.

[0220] When the switching from the high reduction ratio mode to the low reduction ratio mode is started based on conditions such as the running speed and accelerator opening of the vehicle, first, the drive cam 38 is rotationally driven by the electric actuator 32 to switch the rotational transmission state switching device 12 to the one-way clutch mode, and the phase regarding the rotational direction of the drive cam 38 is moved to the clutch touch point θ f (S1). The clutch touch point θ f is the point where the elastic biasing mechanism 30 starts to generate a force that presses the first friction plate 33 and the second friction plate 34 against each other.

[0221] In other words, the clutch touch point θ f is the point where the end portion on the other side in the axial direction of the piston 36 starts to contact the first friction plate 33 or the second friction plate 34 located on the most axially one - side, that is, the point where the clutch clearance C f (see Fig. 25) becomes 0. In this example, the clutch touch point θ f is obtained in advance by the clutch touch point detection function.

[0222] When the phase regarding the rotational direction of the drive cam 38 is moved to the clutch touch point θ f , it shifts to the torque phase (S2). In the torque phase, the drive cam 38 is rotationally driven at a predetermined rotational speed (rotational velocity) by the electric actuator 32, and by reducing the amount of climbing of the rolling element 40 from the first bottom portion 52a, the pressing force between the first friction plate 33 and the second friction plate 34, that is, the fastening force F of the friction engagement portion 29 is gradually increased. At the same time, the output torque (drive torque, power running torque) of the drive motor 2 is gradually increased.

[0223] That is, if the output torque of the drive motor 2 is kept constant, in the torque phase, as the fastening force F of the friction engagement portion 29 increases, the torque transmitted to the friction engagement portion 29 increases, so the rotational torque of the output member 9 decreases. Therefore, in the two-stage transmission 3 of this example, so that the rotational torque of the output member 9 can be maintained substantially constant regardless of the increase in the fastening force F of the friction engagement portion 29, that is, in accordance with the increase in the fastening force F of the friction engagement portion 29, that is, the rotation amount of the drive cam 38, the output torque of the drive motor 2 is gradually increased.

[0224] Note that the relationship between the rotation amount of the drive cam 38 and the increase amount of the output torque of the drive motor 2 is obtained in advance by experiments or calculations. In this example, the rotation speed of the drive cam 38 in S2 is made smaller than the rotation speed of the drive cam 38 in S1. However, the rotation speed of the drive cam 38 in S2 can also be made the same as the rotation speed of the drive cam 38 in S1, or can be made larger than the rotation speed of the drive cam 38 in S1.

[0225] In S2, more specifically, the drive cam 38 is rotated by a predetermined angle, and at the same time, the output torque of the drive motor 2 is increased by an amount corresponding to the rotation amount of the drive cam 38. Then, in the next S3, it is determined whether or not the torque phase has ended.

[0226] That is, in the torque phase, as the fastening force F of the friction engagement portion 29 increases, the clutch torque transmitted to the friction engagement portion 29 increases, and the torque applied to the second member 75 of the rotation transmission state switching device 12 in the direction opposite to the predetermined direction gradually decreases. The torque applied to the second member 75 in the direction opposite to the predetermined direction gradually decreases to 0.

[0227] In this example, when switching from the high reduction ratio mode to the low reduction ratio mode during normal forward travel, since the two-speed transmission 3 is switched to the reduction ratio switching mode, after the torque applied to the second member 75 in the direction opposite to the predetermined direction becomes zero, when the direction of the torque applied to the second member 75 is reversed (the torque in the predetermined direction is applied to the second member 75), at that moment, the rotation of the second member 75 in the predetermined direction is permitted, and the rotation of the sun gear 104 is permitted. When the sun gear 104 rotates, the rotational speed R of the motor output shaft 7 of the drive motor 2 s begins to decrease.

[0228] Therefore, in this example, based on the output signal of the input rotation sensor 112 attached to the motor output shaft 7 of the drive motor 2, when it is determined that the rotational speed R of the motor output shaft 7 s has decreased by a predetermined value or more, it is determined that the torque phase has ended. This determination is made based on the input rotation sensor 112 attached to the motor output shaft 7 of the drive motor 2.

[0229] If the rotational speed R of the motor output shaft 7 s is substantially constant, that is, if the decrease amount of the rotational speed R of the motor output shaft 7 s is smaller than the predetermined value and it is determined that the torque phase has not ended, the process returns to S2.

[0230] In S3, if the decrease amount of the rotational speed R of the motor output shaft 7 s is equal to or greater than the predetermined value and it is determined that the torque phase has ended, the process proceeds to the inertia phases (S4-1 to S4-3).

[0231] In the inertia phases, first, the output torque of the drive motor 2 is rapidly decreased to promote a further decrease in the rotational speed R of the motor output shaft 7 (S4-1). The decrease amount of the output torque of the drive motor 2 is not particularly limited as long as it can promote a further decrease in the rotational speed R of the motor output shaft 7. Specifically, for example, the output torque of the drive motor 2 can be decreased to 0 or a negative value. s s s Specifically, for example, the output torque of the drive motor 2 can be decreased to 0 or a negative value.

[0232] The rotational speed R of the motor output shaft 7 s Once the rotational speed R of the motor output shaft 7 starts to decrease, the output torque of the drive motor 2 is increased so that the rotational torque of the input member 8 becomes the target torque, which is the rotational torque that the output member 9 should output in the state where the switching to the low reduction ratio mode of the two-speed transmission 3 is completed (S4-2). In this example, since the rotational torque of the output member 9 is kept substantially constant before and after the switching from the high reduction ratio mode to the low reduction ratio mode, the output torque of the drive motor 2 is increased until the rotational torque of the input member 8 becomes equal to the rotational torque of the output member 9 at the start of the switching from the high reduction ratio mode to the low reduction ratio mode.

[0233] The speed at which the output torque of the drive motor 2 is increased is not particularly limited as long as the rotational torque of the input member 8 can be increased to the target torque by the time the inertia phases are completed. For example, according to the difference (differential rotation) ΔR between the rotational speed R in of the input member 8 and the rotational speed R out of the output member 9, the output torque of the drive motor 2 can be controlled. More specifically, as the rotational speed R s of the motor output shaft 7 decreases, the rotational speed R in of the input member 8 decreases, and as the differential rotation ΔR decreases, the output torque of the drive motor 2 is increased, and when the differential rotation ΔR becomes 0, it is possible to control so that the rotational torque of the input member 8 becomes the target torque.

[0234] Next, in S4-3, it is determined whether the rotational speed R in of the input member 8 is equal to the rotational speed R out of the output member 9. Specifically, it is determined whether the difference (differential rotation) ΔR between the rotational speed R in of the input member 8 and the rotational speed R out of the output member 9 is within a predetermined range. This determination is made based on the output signal of the input rotation sensor 112 or the output signals of the rotation sensors respectively attached to the input member 8 and the output member 9.

[0235] If the differential rotation ΔR is not within the predetermined range, that is, the rotational speed R in of the input member 8 and the rotational speed R of the output member 9out When it is determined that they are not equal, after a predetermined time has elapsed, S4-3 is executed again.

[0236] The differential rotation ΔR is within a predetermined range, that is, the rotational speed R of the input member 8 in and the rotational speed R of the output member 9 out When it is determined that they are equal, it is determined that the inertia phase has ended, and the process proceeds to the next S5.

[0237] In S5, the drive cam 38 is rotated by the electric actuator 32 to a phase with respect to a predetermined circumferential direction, the rolling element 40 is positioned at the first bottom portion 52a of the drive cam surface 52, and the driven cam 39 is displaced toward the other axial side in the direction in which the axial distance from the drive cam 38 is reduced. Thereby, the piston clearance C between the end portion on one axial side of the pressing member 62 and the side surface on the other axial side of the piston 36 p is ensured. In other words, the piston clearance C p is made 0 or more, preferably greater than 0.

[0238] After moving the rolling element 40 to the first bottom portion 52a, proceed to the end. As described above, the two-speed transmission 3 is switched from the high reduction ratio mode to the low reduction ratio mode. Thereafter, by maintaining the phase of the drive cam 38 with respect to the circumferential direction, the two-speed transmission 3 is maintained in the low reduction ratio mode.

[0239] As described above, in the drive device 1 for an electric vehicle of this example, by controlling the drive motor 2 and the shift motor 70, even when switching between the high reduction ratio mode and the low reduction ratio mode during normal forward travel, it is possible to prevent the rotational torque of the output member 9 from changing (suddenly) and prevent the occurrence of a shift shock. However, in order to prevent the occurrence of a shift shock, the output torque and rotational speed R of the drive motor 2 s and the timing for controlling the rotational speed (rotation amount) of the shift motor 70 are important.

[0240] For example, the phase with respect to the rotational direction of the drive cam 38 is the clutch touch point θ fEven though it has not reached that point yet, if it shifts to S2 and increases the output torque of the drive motor 2, as indicated by the dashed line in Fig. 27(F), the rotational torque of the output member 9 may inadvertently increase.

[0241] Here, as the use of the two-speed transmission 3 progresses and the wear amounts of the first friction plate 33 and the second friction plate 34 increase, the required pressing amount of the first friction plate 33 or the second friction plate 34 on the other axial side by the elastic biasing mechanism 30 for switching the electric friction clutch device 11 to the connection mode increases. In other words, when switching the electric friction clutch device 11 to the disconnection mode, the required pressing amount of the piston 36 on one axial side by the cam device 31 decreases. As a result, the relationship between the rotation angle θ of the drive cam 38 and the current value A of the shift motor 70 changes as shown in Fig. 22(A) and Fig. 22(B) in that order. That is, as is clear from Fig. 22(A) and Fig. 22(B), when the wear amounts of the first friction plate 33 and the second friction plate 34 increase, the clutch touch point θ f becomes smaller.

[0242] Figs. 22(A) and 22(B) are diagrams showing the relationship between the rotation angle θ of the drive cam 38, the output torque T of the shift motor 70, and the current value A when switching the electric friction clutch device 11 from the connection mode to the disconnection mode. Fig. 22(A) shows the case when the first friction plate 33 and the second friction plate 34 are new and not worn, and Fig. 22(B) shows the case when the wear of the first friction plate 33 and the second friction plate 34 has progressed significantly.

[0243] As is clear from Fig. 22(A) and Fig. 22(B), when the wear amounts of the first friction plate 33 and the second friction plate 34 increase, the piston touch point θ p also becomes smaller. The piston touch point θ p is the point at which, when the drive cam 38 is rotated in the direction of switching the friction engagement portion 29 from the connected state to the disconnected state, the elastic biasing mechanism 30 begins to be pressed in the direction of releasing the force that presses the first friction plate 33 and the second friction plate 34 against each other. In other words, the piston touch point θ pWhen the drive cam 38 is rotated in a direction to switch the friction engagement portion 29 from the disconnected state to the connected state, the piston clearance C between the end on one axial side of the pressing member 62 and the side surface on the other axial side of the piston 36 p (see Fig. 23) starts to occur.

[0244] In the drive device 1 for an electric vehicle of this example, the control device 6 has a function for preventing shift shock regardless of the wear of the first friction plate 33 and the second friction plate 34. Specifically, the control device 6 has a piston touch point detection function for detecting the piston touch point θ p , a clutch touch point detection function for detecting the clutch touch point θ f , and a touch point adjustment function for adjusting the rotation amount of the drive cam 38 based on the piston touch point θ p and / or the clutch touch point θ f when switching between the high reduction ratio mode and the low reduction ratio mode.

[0245] As is also apparent from Figs. 22(A) and 22(B), when the electric friction clutch device 11 is switched between modes, the output torque T of the shift motor 70 and the current value A of the shift motor 70 change in the same tendency. The two-speed transmission 3 of this example detects the piston touch point θ p and the clutch touch point θ f based on the current value A of the shift motor 70 when the electric friction clutch device 11 is switched from the connected mode to the disconnected mode.

[0246] In a state where the electric friction clutch device 11 is switched to the connected mode, the rolling element 40 of the cam device 31 is located at the first bottom portion 52a of the drive cam surface 52. In this state, as shown in Fig. 23, there is a piston clearance C between the end on one axial side of the pressing member 62 and the side surface on the other axial side of the piston 36 p existing. This piston clearance C pBased on the presence of , displacement of the piston 36 toward the other axial side is permitted. Accordingly, due to the force with which the elastic member 37 attempts to elastically restore, the piston 36 is elastically pressed toward the other axial side, and by this piston 36, the first friction plate 33 or the second friction plate 34 on the most axial one side is pressed toward the other axial side, whereby the first friction plate 33 and the second friction plate 34 are pressed against each other.

[0247] To switch the electric friction clutch device 11 from the connection mode to the disconnection mode, based on energization of the shift motor 70, the drive cam 38 is rotated in the predetermined direction, and the amount of the rolling element 40 riding up from the first bottom portion 52a is increased. At this time, the current value A of the shift motor 70 becomes substantially constant (range α in FIGS. 22(A) and 22(B)) except for the starting current that flows temporarily.

[0248] By increasing the amount of the rolling element 40 riding up from the first bottom portion 52a and moving the pressing member 62 toward the one axial side, as shown in FIG. 24, the end portion on the one axial side of the pressing member 62 comes into contact with the side surface on the other axial side of the piston 36. In other words, the piston clearance C p becomes zero.

[0249] When, from the state shown in FIG. 24, the drive cam 38 is rotationally driven in the predetermined direction by the shift motor 70 further, the piston 36 is pressed toward the one axial side against the elastic restoring force of the elastic member 37 by the driven cam 39 via the pressing member 62. In this state, a part of the elastic restoring force of the elastic member 37 is supported by the cam device 31 via the pressing member 62 and the thrust bearing 61, and the remainder is supported by the fixed portion 14 via the friction engagement portion 29 and the rotation transmission state switching device 12. As the piston 36 is pressed toward the one axial side, the force pressing the first friction plate 33 and the second friction plate 34 against each other gradually decreases mainly based on the elastic restoring force of the second friction plate 34 and the elastic member 37. That is, the fastening force F of the friction engagement portion 29 gradually decreases.

[0250] While gradually decreasing the fastening force F of the friction engagement portion 29, the current value A of the shift motor 70 increases at a substantially constant rate of increase (slope) (range β in FIGS. 22(A) and 22(B)). That is, the rate of increase of the current value A in range β is greater than the rate of increase of the current value A in range α.

[0251] Therefore, after the control device 6 starts energizing the shift motor 70 in order to switch the electric friction clutch device 11 from the connection mode to the disconnection mode by means of the piston touch point detection function, when the current value A of the shift motor 70 starts to increase at a rate of increase equal to or greater than a predetermined first threshold value, the phase (rotation angle from the reference position (for example, the initial position where the rolling element 40 is located at the bottom of the concave portion)) θ regarding the rotation direction of the drive cam 38 is determined as the piston clearance C p of the piston touch point θ at which the piston clearance C becomes 0 p and is detected. The first threshold value can be obtained in advance through experiments, simulations, etc.

[0252] Note that the rate of increase of the current value A is the increase amount ΔA of the current value A per unit rotation angle Δθ of the drive cam 38. When the drive cam 38 is rotated in the predetermined direction at a constant rotation speed, the increase amount ΔA of the current value A per unit time can also be used for the determination.

[0253] As the fastening force F of the friction engagement portion 29 gradually decreases and the fastening force F becomes 0, from that moment on, as shown in FIG. 25, a clutch clearance C is generated between the end portion on the other side in the axial direction of the piston 36 and the first friction plate 33 or the second friction plate 34 located on the most axially one - side. f begins to occur. When the clutch clearance C f begins to occur, almost all of the elastic restoring force of the elastic member 37 is supported by the cam device 31 via the pressing member 62 and the thrust bearing 61. In this way, the clutch clearance C fAfter it starts to occur, the current value A of the shift motor 70 increases gently and logarithmically (range γ in FIGS. 22(A) and 22(B)). That is, the increase rate of the current value A in range γ is smaller than the increase rate of the current value A in range β.

[0254] When the control device 6 switches the electric friction clutch device 11 from the connection mode to the disconnection mode by the clutch touch point detection function, the phase regarding the rotation direction of the drive cam 38 is the piston touch point θ p After exceeding, the control device 6 detects, as the clutch clearance C f the phase θ regarding the rotation direction of the drive cam 38 when the increase rate of the current value A of the shift motor 70 becomes equal to or less than a predetermined second threshold value at the clutch touch point θ f where the clutch clearance C becomes 0. Note that the second threshold value is smaller than the first threshold value. The second threshold value can be obtained in advance by experiments, simulations, or the like.

[0255] Note that the detection of the piston touch point θ p and the clutch touch point θ f can be carried out at an arbitrary timing as long as it does not interfere with the running of an automobile equipped with the two-speed transmission 3. Specifically, for example, it can be carried out at a timing such as immediately after turning on the ignition key, during kick-down acceleration, or during engine brake operation when switching the two-speed transmission from the low reduction ratio mode to the high reduction ratio mode. However, when trying to carry out the above operation during the running of the vehicle, there are problems such as the drive cam 38 not being able to be driven at an arbitrary rotational speed. For this reason, the detection of the piston touch point θ p and the clutch touch point θ f is preferably carried out while the vehicle is stopped, such as immediately after turning on the ignition key.

[0256] In the drive device 1 for an electric vehicle of this example, when switching between the high reduction ratio mode and the low reduction ratio mode, the control device 6 adjusts the rotation amount of the drive cam 38 that is rotationally driven by the shift motor 70 via the speed reducer 71 based on the piston touch point θ p detected by the piston touch point detection function and / or the clutch touch point θ f detected by the clutch touch point detection function. Specifically, for example, when maintaining the rotational torque of the output member 9 substantially constant before and after switching from the high reduction ratio mode to the low reduction ratio mode, at S1, as the target value of the phase regarding the rotation direction of the drive cam 38, the clutch touch point θ f detected by the clutch touch point detection function is used.

[0257] Thus, in the drive device 1 for an electric vehicle of this example, even when the piston touch point θ p and the clutch touch point θ f change from the initial position due to wear of the first friction plate 33 and the second friction plate 34, the shift control can be implemented based on the corrected piston touch point θ p and the clutch touch point θ f Therefore, according to the drive device 1 for an electric vehicle of this example, it is possible to prevent the occurrence of shift shock regardless of the wear of the first friction plate 33 and the second friction plate 34.

[0258] In the drive device 1 for an electric vehicle of this example, since it passes through the reduction ratio switching mode during the switching from the high reduction ratio mode to the low reduction ratio mode during normal forward driving, it is possible to suppress torque loss while suppressing the shift shock associated with the mode switching. The reason for this will be described while referring to FIGS. 30 and 31.

[0259] FIG. 30 shows a part of a two-speed transmission of a comparative example. The two-speed transmission of the comparative example includes a first friction engagement device 201 that switches the possibility of relative rotation between the input member 8 and the rotating member 10, in other words, the possibility of relative rotation between the ring gear 105 and the sun gear 104, and a second friction engagement device 202 that switches the possibility of rotation of the rotating member 10 relative to the fixed portion 14, in other words, the possibility of rotation of the sun gear 104. That is, instead of the rotation transmission state switching device 12 of the two-speed transmission of this example, the two-speed transmission of the comparative example employs a second friction engagement device 202 that switches modes by pressing and separating a first friction plate 33 and a second friction plate 34.

[0260] In the comparative example, the drive cam 38z of the cam device 31z is rotationally driven by an electric actuator, and based on displacing the first driven cam 203 and the second driven cam 204 in the axial direction, the mode of the first friction engagement device 201 and the mode of the second friction engagement device 202 are switched. The first driven cam 203 and the second driven cam 204 are displaced with different phases from each other as the drive cam 38z rotates (displace in opposite directions (advance and retreat) with respect to the axial direction).

[0261] In the two-speed transmission of the comparative example, during the switching from the high reduction ratio mode with a large reduction ratio to the low reduction ratio mode with a small reduction ratio, as shown in FIG. 31, the fastening force of the first friction engagement device 201 gradually increases, and the fastening force of the second friction engagement device 202 gradually decreases. For this reason, if the fastening force of the second friction engagement device 202 gradually becomes small and is insufficient during the switching from the high reduction ratio mode to the low reduction ratio mode, the sun gear 104 is dragged by the revolution of the planetary gear 107, and torque loss occurs between the rotating member 10 and the fixed portion 14.

[0262] Also, in the two-speed transmission of the comparative example, as the fastening force of the first friction engagement device 201 gradually increases, the torque applied to the sun gear 104 in the direction opposite to the predetermined direction gradually decreases and becomes zero, and then the direction of the torque applied to the sun gear 104 reverses. However, in the two-speed transmission of the comparative example, when the direction of the torque applied to the sun gear 104 reverses and the moment when the revolution direction of the planetary gear 107 coincides with the rotation direction of the sun gear 104, the fastening force of the second friction engagement device 202 cannot be made sufficiently large. For this reason, the sun gear 104 is dragged relative to the fixed portion 14, and torque loss occurs between the sun gear 104 and the fixed portion 14.

[0263] On the other hand, in this example, based on the rotation of the drive cam 38, before starting to switch the electric friction clutch device 11 from the disengagement mode to the engagement mode in order to switch from the high reduction ratio mode to the low reduction ratio mode, the rotation transmission state switching device 12 is set to the one-way clutch mode. For this reason, in order to switch the electric friction clutch device 11 from the disengagement mode to the engagement mode, the fastening force F of the friction engagement portion 29 is gradually increased so that the rotation of the sun gear 104 in the predetermined direction can be allowed at the moment when the direction of the torque applied to the sun gear 104 reverses. For this reason, it is possible to suppress torque loss in the two-speed transmission 3 while suppressing a shift shock associated with mode switching.

[0264] Note that the reduction ratio between the input member 8 and the output member 9 in the reduction ratio switching mode is the same as the reduction ratio in the high reduction ratio mode when the fastening force F of the friction engagement portion 29 is small enough that no torque loss occurs at the contact portions between both axial side surfaces of the first friction plate 33 and both axial side surfaces of the second friction plate 34. On the other hand, when the fastening force F of the friction engagement portion 29 increases to such an extent that torque can be transmitted without slippage occurring at the contact portions between both axial side surfaces of the first friction plate 33 and both axial side surfaces of the second friction plate 34, it is the same as the reduction ratio in the low reduction ratio mode, that is, 1.

[0265] When the fastening force F of the friction engagement portion 29 causes slippage at the contact portions between the axially opposite side surfaces of the first friction plate 33 and the axially opposite side surfaces of the second friction plate 34, the reduction ratio between the input member 8 and the output member 9 becomes a value corresponding to the magnitude of the input torque, the rotational speed, and the like.

[0266] When the input member 8 is rotating in the forward rotation direction and during the switching from the high reduction ratio mode to the reduction ratio switching mode, torque is applied to the second member 75 of the rotation transmission state switching device 12 in a direction opposite to the predetermined direction. Here, in the rotation transmission state switching device 12, the rotation of the second member 75 in the direction opposite to the predetermined direction is blocked even during the switching from the lock mode to the one-way clutch mode. That is, the reduction ratio between the input member 8 and the output member 9 during the switching from the high reduction ratio mode to the reduction ratio switching mode is the same as the reduction ratio in the high reduction ratio mode.

[0267] When the input member 8 is rotating in the forward rotation direction and during the switching from the reduction ratio switching mode to the low reduction ratio mode, torque is applied to the second member 75 of the rotation transmission state switching device 12 in the predetermined direction. Here, in the rotation transmission state switching device 12, the rotation of the second member 75 in the predetermined direction is allowed even during the switching from the one-way clutch mode to the free mode.

[0268] Incidentally, when the input member 8 rotates in the reverse direction, that is, when the vehicle equipped with the drive device 1 for an electric vehicle of this example is reversing, it is almost impossible for the vehicle to travel at a high speed. Therefore, when the input member 8 is rotating in the reverse direction, when switching from the high reduction ratio mode to the low reduction ratio mode, like when rotating in the forward direction, by setting the electric friction clutch device 11 to the one-way clutch mode, there is little need to switch to the reduction ratio switching mode that allows the rotation of the sun gear 104 at the moment when the direction of the torque applied to the sun gear 104 is reversed. Also, even when the input member 8 is rotating in the forward direction, when switching from the low reduction ratio mode to the high reduction ratio mode, mainly the vehicle is in a decelerated state. In this case, since the power is not transmitted from the input member 8 to the output member 9, there is little need to switch the two-speed transmission 3 to the reduction ratio switching mode.

[0269] Next, the cooperative control function provided in the control device 6 will be described. The cooperative control function is in a state where torque is passing through the two-speed transmission 3 from the output member 9 side toward the input member 8 side, and a torque that attempts to rotate the first member 74 in one circumferential direction with respect to the second member 75 is applied to the first member 74, and the rotation of the first member 74 in one circumferential direction with respect to the second member 75 is blocked by the rotation transmission state switching device 12. In this case, when the mode of the two-speed transmission 3 is switched by the reduction ratio switching function, before the second engaging claw 97 is radially pressed by the protruding portion 100 and retracted from the engaging recess 77, a pre-shift process is executed to increase the braking force by the friction brake device 5 while reducing the regenerative torque of the drive motor 2.

[0270] That is, when switching the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode in a state where torque is transmitted through the two-speed transmission 3 from the output member 9 side toward the input member 8 side, that is, during regenerative running of the vehicle, it is necessary to switch the electric friction clutch device 11 from the disconnection mode to the connection mode, switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, and further switch to the free mode.

[0271] Here, when the vehicle equipped with the drive device 1 for an electric vehicle is in a state of regenerative running forward in the high reduction ratio mode, a torque is applied to the first member 74 of the rotation transmission state switching device 12 to rotate the first member 74 in the one circumferential direction with respect to the second member 75. For this reason, the side surface facing the one circumferential direction among the inner surfaces of the engagement recess 77 provided in the first member 74 is pressed against the tip surface of the second engagement claw 97. For this reason, during the switching from the high reduction ratio mode to the low reduction ratio mode of the two-stage transmission 3, in order to release the engagement between the engagement recess 77 and the second engagement claw 97 to switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, the protrusion 100 of the mode select member 76 may cause the force required to press the second engagement claw 97 radially outward to become excessive.

[0272] Therefore, in the drive device 1 for an electric vehicle of this example, when switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode during the switching from the high reduction ratio mode to the low reduction ratio mode of the two-stage transmission 3 while the vehicle is in a state of regenerative running, by coordinately controlling the regenerative torque T2 of the drive motor 2 and the braking force BF by the friction brake device 5 by the cooperative control function, it is possible to prevent the force required for the mode switching of the rotation transmission state switching device 12 from becoming excessive and suppress or prevent giving a sense of discomfort to the occupant.

[0273] In the drive device 1 for an electric vehicle of this example, the VCU 116 controls the rotational speed and torque of the drive motor 2 via the inverter 115 based on signals from various sensors, controls the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12 via the TCU 114, and controls the braking force by the friction brake device 5, thereby executing the cooperative control function.

[0274] While torque is being transmitted from the output member 9 side to the input member 8 side of the two-speed transmission 3, the rotational speed and torque of the drive motor 2, the mode of the electric friction clutch device 11 and the mode of the rotational transmission state switching device 12, and the braking force by the friction brake device 5 are controlled in cooperation. While executing the cooperative control, a method of switching the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode will be described with reference to FIGS. 28 and 29. The following example is an example in which the rotational speed of the output member 9 is maintained substantially constant before and after switching from the high reduction ratio mode to the low reduction ratio mode.

[0275] When torque is being transmitted from the output member 9 side to the input member 8 side of the two-speed transmission 3, that is, during regenerative running of the vehicle, based on conditions such as the running speed of the vehicle, when switching from the high reduction ratio mode to the low reduction ratio mode is started by the reduction ratio switching function, first, as a pre-shift process, the control device 6 controls the drive motor 2 and the friction brake device 5 in cooperation. Specifically, by controlling the energization of the drive motor 2, while reducing the regenerative torque T2 by the drive motor 2 (P1-1), the braking force BF by the friction brake device 5 is increased (P1-2). Here, when the regenerative torque T2 by the drive motor 2 is reduced, the torque T9 passing through the output member 9 in the direction from the drive wheel 108 side to the drive motor 2 side also decreases.

[0276] More specifically, in this example, while reducing the regenerative torque T2 by the drive motor 2 until it becomes 0, the braking force BF by the friction brake device 5 is increased so that the rotational speed R out of the output member 9 is maintained substantially constant.

[0277] In this example, the regenerative torque T2 by the drive motor 2 is decreased until it becomes 0. However, when implementing the drive device for an electric vehicle of the present disclosure, in the following first mode switching step (P2), as long as the force required to rotate the mode select member 76 can be reduced in order to switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, that is, in order for the protruding portion 100 to push only the second engaging claw 97 radially outward against the elastic force of the second claw biasing member 92, the regenerative torque T2 can be made greater than 0.

[0278] In FIG. 29, the fact that the value of T2 is negative means that it is a regenerative torque. Increasing the regenerative torque means making T2 larger in the negative direction (increasing the absolute value of the negative value), and decreasing the regenerative torque means making the value of T2 approach 0 (decreasing the absolute value of the negative value).

[0279] Also, in FIG. 29, for ease of understanding of the invention, the braking force BF by the friction braking device 5 is represented by a negative value. Increasing the braking force BF means making the braking force BF larger in the negative direction (increasing the absolute value of the negative value). In FIG. 29, the fact that the value of the torque T9 of the output member 9 is negative means that the torque passes through the output member 9 in the direction from the drive wheel 108 side toward the drive motor 2 side.

[0280] During the pre-shift process of decreasing the regenerative torque T2 by the drive motor 2 and increasing the braking force BF by the friction braking device 5, the drive wheel 108 is decelerated by the combined braking force of the regenerative braking force T2 by the drive motor 2 and the friction braking force BF by the friction braking device 5. After the regenerative torque T2 by the drive motor 2 becomes 0, the drive wheel 108 is decelerated by the friction braking force BF by the friction braking device 5.

[0281] In the next first mode switching step (P2), based on rotationally driving the drive cam 38 by the electric actuator 32, the mode select member 76 is rotationally driven, thereby switching the rotational transmission state switching device 12 from the lock mode to the one-way clutch mode.

[0282] That is, as shown in FIGS. 20(B) and 20(C) in this order, the circumferential phase of the mode select member 76 with respect to the second member 75 is adjusted, and only the second engaging claw 97 is pushed radially outward against the elastic force of the second claw biasing member 92 by the protruding portion 100 and retracted from the engaging recess 77. Thereby, the rotational transmission state switching device 12 is switched to the one-way clutch mode in which only the rotation of the first member 74 in the predetermined direction (clockwise direction in FIG. 20(C)) with respect to the second member 75 is allowed and the rotation in the direction opposite to the predetermined direction is blocked.

[0283] Once the rotational transmission state switching device 12 is switched to the one-way clutch mode, the process proceeds to the next inertia step (P3 to P4).

[0284] In the inertia step, first, by controlling the energization to the drive motor 2, the regeneration torque T2 by the drive motor 2 is increased, thereby promoting the decrease in the rotational speed R s of the motor output shaft 7 (P3).

[0285] The speed and amount of increasing the regeneration torque T2 by the drive motor 2 are not particularly limited as long as they can promote the decrease in the rotational speed R s of the motor output shaft 7. However, in order to quickly reduce the rotational speed R s of the motor output shaft 7 to quickly perform the mode switching of the two-speed transmission 3, it is preferable to increase it as quickly as possible within a range where an excessive load is not applied to the drive motor 2.

[0286] When the rotational speed R s of the motor output shaft 7 starts to decrease, the regeneration torque T2 by the drive motor 2 is decreased (P4). Specifically, the rotational speed R sWhen the reduction reaches a predetermined target value, the regenerative torque T2 by the drive motor 2 is decreased so that the regenerative torque T2 by the drive motor 2 becomes 0. More specifically, in this example, the rotational speed R of the motor output shaft 7 s is the rotational speed R of the output member 9 before the start of the mode switching of the two-speed transmission 3 out When the reduction reaches the rotational speed R of the output member 9 before the start of the mode switching of the two-speed transmission 3, the regenerative torque T2 by the drive motor 2 is decreased so that the regenerative torque T2 by the drive motor 2 becomes 0.

[0287] In the next inertia phase end determination step (P5), it is determined whether or not the inertia step has ended. Specifically, it is determined whether or not the rotational speed R of the motor output shaft 7 detected by the input rotation sensor 112 s has reached the target value. More specifically, in this example, the rotational speed R of the motor output shaft 7 s is the rotational speed R of the output member 9 before the start of the mode switching of the two-speed transmission 3 out and it is determined whether or not they are equal.

[0288] When it is determined that the rotational speed R of the motor output shaft 7 s has not reached the target value, after a predetermined time has elapsed, the torque phase end determination step (P5) is executed again.

[0289] When it is determined that the rotational speed R of the motor output shaft 7 s has reached the target value, it is determined that the inertia step has ended, and the process proceeds to the next shift completion steps (P6 to P8).

[0290] In the shift completion steps, first, the drive cam 38 is rotated by the electric actuator 32, and the fastening force F of the friction engagement portion 29 of the electric friction clutch device 11 is increased to a predetermined magnitude (P6). Specifically, the fastening force F of the friction engagement portion 29 is such that the torque that can be transmitted without the first friction plate 33 and the second friction plate 34 slipping relative to each other is equal to or greater than the torque that passes through the friction engagement portion 29 after the completion of the switching to the low reduction ratio mode of the two-speed transmission 3, preferably greater than the torque that passes through the friction engagement portion 29 after the completion of the switching to the low reduction ratio mode of the two-speed transmission 3.

[0291] Next, while reducing the braking force BF by the friction brake device 5 (P7-1), the regeneration torque T2 by the drive motor 2 is increased (P7-2). Specifically, when the braking force BF by the friction brake device 5 becomes 0, the regeneration torque T2 by the drive motor 2 is increased until the magnitude of the rotational torque T9 of the output member 9 becomes substantially the same as the magnitude of the rotational torque T9 of the output member 9 at the time when the mode switching of the two-speed transmission 3 is started.

[0292] While reducing the braking force BF by the friction brake device 5 and increasing the regeneration torque T2 by the drive motor 2, the drive wheels 108 are decelerated by the combined braking force of the regeneration braking force T2 (regeneration braking force) by the drive motor 2 and the friction braking force BF by the friction brake device 5. After the braking force BF by the friction brake device 5 becomes 0, the drive wheels 108 are decelerated by the regeneration torque T2 (regeneration braking force) by the drive motor 2.

[0293] After reducing the braking force BF by the friction brake device 5 to 0, the drive cam 38 is rotated by the electric actuator 32, and the rotation transmission state switching device 12 is switched to the free mode, thereby completing the switching of the two-speed transmission 3 to the low reduction ratio mode (P8), and then it ends.

[0294] In the drive device 1 for an electric vehicle of this example, during the regenerative running of the vehicle, before switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode in order to switch the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode, the regeneration torque T2 by the drive motor 2 is decreased. Therefore, the force pressing the side surface facing one side in the circumferential direction among the inner surfaces of the engagement recess 77 provided in the first member 74 against the tip surface of the second engagement claw 97 can be reduced.

[0295] Specifically, in this example, before switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, since the regenerative torque T2 by the drive motor 2 is set to 0, the force pressing the side surface of the inner surface of the engagement recess 77 facing one side in the circumferential direction against the tip surface of the second engagement claw 97 can be lost.

[0296] In this example, since the force pressing the side surface of the inner surface of the engagement recess 77 facing one side in the circumferential direction against the tip surface of the second engagement claw 97 can be reduced or lost, in order to disengage the engagement between the engagement recess 77 and the second engagement claw 97 to switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, the force required to press the second engagement claw 97 radially outward by the protrusion 100 of the mode select member 76 can be suppressed to be small. As a result, even when the two-speed transmission 3 is switched from the high reduction ratio mode to the low reduction ratio mode during the regenerative running of the vehicle, the mode switching of the rotation transmission state switching device 12 can be smoothly performed.

[0297] Also, in the drive device 1 for an electric vehicle of this example, during the regenerative running of the vehicle, while reducing the regenerative torque T2 by the drive motor 2 in cooperation with increasing the braking force BF on the drive wheels 108 by the friction brake device 5 before switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode during the switching of the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode. For this reason, even when the regenerative torque T2 by the drive motor 2 is reduced, it is possible to suppress or prevent the feeling of the deceleration acceleration (deceleration G) being lost, and it is possible to suppress or prevent giving a sense of discomfort to the driver and other passengers.

[0298] In this example, the case where the torque is transmitted from the output member 9 side to the input member 8 side of the two-speed transmission 3 and the two-speed transmission 3 is switched from the high reduction ratio mode to the low reduction ratio mode, and the rotational speed of the output member 9 is maintained substantially constant before and after the mode switching of the two-speed transmission 3 has been described. However, when implementing the present disclosure, the rotational speed of the output member can also be changed before and after the mode switching of the two-speed transmission. Specifically, by adjusting the regenerative torque by the drive motor and / or the braking force by the friction brake device, the rotational speed of the output member after the mode switching of the two-speed transmission can be adjusted.

[0299] Further, according to the drive device 1 for an electric vehicle of this example, good torque transmission efficiency can be ensured. The reason for this will be described next.

[0300] In a state where the cam device 31 generates a pressing force, that is, in a state where the driven cam 39 presses the piston 36 toward one axial side via the thrust bearing 61 and the pressing member 62 (the state shown in FIG. 3(B)), a force directed toward one axial side is applied to the thrust bearing 61. Further, a reaction force accompanying the pressing of the piston 36 toward one axial side by the driven cam 39 is applied to the radial bearing 42 toward the other axial side via the rolling element 40 and the driving cam 38.

[0301] The raceway ring 63a on one axial side constituting the thrust bearing 61 is supported by the rotating member 10 via the pressing member 62 and the piston 36, and the raceway ring 63b on the other axial side is supported by the fixed portion 14 via the cam device 31, the angular ball bearing 43, and the cylindrical member 41. Further, the inner ring 46 constituting the radial bearing 42 is externally fitted and fixed to the rotating member 10, and the outer ring 47 is supported by the driving cam 38 of the cam device 31 via the cylindrical member 41 and the angular ball bearing 43.

[0302] Here, in this example, in a state where the cam device 31 generates a pressing force, that is, the piston 36 is pressed toward one axial side, the axial dimension of the elastic member 37 is elastically contracted, and the force that presses the first friction plate 33 and the second friction plate 34 against each other is released and the electric friction clutch device 11 is disengaged, the rotation transmission state switching device 12 enters the lock mode. In the high reduction ratio mode where the electric friction clutch device 11 is disengaged and the rotation transmission state switching device 12 is switched to the lock mode, relative rotation of the rotating member 10 with respect to the fixed portion 14 is blocked. In this state, the raceway ring 63a on one axial side and the raceway ring 63b on the other axial side that constitute the thrust bearing 61 do not rotate relative to each other, and the inner ring 46 and the outer ring 47 that constitute the radial bearing 42 do not rotate relative to each other.

[0303] In short, when axial forces (the left - right direction in FIG. 2(B)) are applied to the thrust bearing 61 and the radial bearing 42 and the rolling resistance increases, the raceway ring 63a on one axial side and the raceway ring 63b on the other axial side that constitute the thrust bearing 61 do not rotate relative to each other, and the inner ring 46 and the outer ring 47 that constitute the radial bearing 42 do not rotate relative to each other. Therefore, it is possible to prevent the occurrence of torque loss in the thrust bearing 61 and the radial bearing 42.

[0304] Note that the pressing force generated by the cam device 31 is applied to the rotating member 10 in the direction of one axial side from the driven cam 39 via the pressing member 62, the thrust bearing 61, the piston 36, and the elastic member 37. On the contrary, the reaction force accompanying the generation of the pressing force by the cam device 31 is applied to the rotating member 10 in the direction of the other axial side from the driving cam 38 via the radial bearing 42. Thus, the axial forces accompanying the generation of the pressing force by the cam device 31 cancel each other out (are offset) within the rotating member 10.

[0305] On the other hand, when the rotation transmission state switching device 12 switches to the free mode and the relative rotation of the rotating member 10 with respect to the fixed portion 14 is permitted (the state shown in FIG. 3(A)), the electric friction clutch device 11 is connected and the cam device 31 does not generate a pressing force. In this state, no axial force (the left-right direction in FIG. 3(A)) is applied to the thrust bearing 61 and the radial bearing 42 due to the pressing force generated by the cam device 31. Therefore, the rolling resistance of the thrust bearing 61 and the radial bearing 42 does not increase unnecessarily, and the torque loss does not become excessively large.

[0306] In short, in the drive device 1 for an electric vehicle of this example, except for a short time during mode switching, an axial force is applied due to the pressing force generated by the cam device 31, and the thrust bearing 61 and the radial bearing 42 do not rotate in a state where the rolling resistance has increased. Therefore, it is possible to prevent excessive torque loss from occurring in the thrust bearing 61 and the radial bearing 42, and it is possible to ensure good torque transmission efficiency of the two-speed transmission 3.

[0307] The two-speed transmission of the present disclosure can also be applied to a structure including a rotation transmission state switching device that does not have a one-way clutch mode, that is, has only a free mode and a lock mode. In such a modification, when switching from the high reduction ratio mode to the low reduction ratio mode, as shown in FIG. 32, after switching the rotation transmission state switching device from the lock mode to the free mode, the electric friction clutch device is switched from the disconnection mode to the connection mode.

[0308] According to the two-speed transmission 3 of this example, based on rotating the drive cam 38, the driven cam 39 can be surely displaced in the axial direction, and the mode switching of the two-speed transmission 3 can be accurately performed.

[0309] That is, when balls are used as the rolling elements that make up the cam device, there is a possibility of slippage occurring at the rolling contact portion between the surface of the rolling element and the driving cam surface when the driving cam is rotated. When slippage occurs at the rolling contact portion between the surface of the rolling element and the driving cam surface, the driven cam may become unable to be displaced in the axial direction, or the axial displacement amount of the driven cam with respect to the rotation amount of the driving cam may not be ensured sufficiently.

[0310] In contrast, in the two-speed transmission 3 of this example, a roller is used as the rolling element 40, and the rolling element 40 is freely supported so as to rotate (revolve) about a rotation axis C that faces in the radial direction centered on the central axis of the driven cam 39 with respect to the driven cam 39. For this reason, when the driving cam 38 is rotated, it is possible to prevent slippage from occurring at the rolling contact portion between the outer peripheral surface of the rolling element 40 and the driving cam surface 52, and based on rotating the driving cam 38, the driven cam 39 can be reliably displaced in the axial direction. As a result, the mode switching of the two-speed transmission 3 can be performed accurately. However, as described above, balls can also be used as the rolling elements that make up the cam device.

[0311] [Second Example] A second example of the embodiment of the present disclosure will be described with reference to FIGS. 33 to 35. In the drive device 1a for an electric vehicle of this example, the structure of the two-speed transmission 3a is different from the structure of the two-speed transmission 3 of the first example.

[0312] In this example, the two-speed transmission 3a includes an input member 8a, an output member 9a, a rotating member 10a, an electric friction clutch device 11a, a rotation transmission state switching device 12a, and a planetary gear mechanism 13a.

[0313] In this example, the electric friction clutch device 11a is provided between the rotating member 10a and the input member 8a, and switches between a connection mode for transmitting torque between the rotating member 10a and the input member 8a and a disconnection mode for not transmitting torque. That is, in this example, the second clutch member rotates integrally with the input member 8a. More specifically, the second clutch member is constituted by the input member 8a itself. Further, the first clutch member is constituted by the rotating member 10a itself.

[0314] Also, in this example, the electric friction clutch device 11a is disposed between the friction engagement portion 29 and the driven cam 39 of the cam device 31, and includes an elastic biasing mechanism 30a that elastically biases the friction engagement portion 29 and the driven cam 39 in a direction away from each other.

[0315] The elastic biasing mechanism 30a has an elastic member 37a and a thrust bearing 61a in order from the side of the driven cam 39 between the friction engagement portion 29 and the driven cam 39.

[0316] The elastic member 37a is constituted by a single disc spring.

[0317] The thrust bearing 61a has a pair of raceway rings 63c, 63d and a plurality of rolling elements 64 that are rotatably disposed between the pair of raceway rings 63c, 63d.

[0318] In this example, when switching the electric friction clutch device 11a to the disconnection mode in which torque is not transmitted between the rotating member 10a and the input member 8a, the drive cam 38 is rotationally driven by the electric actuator 32, so that the driven cam 39 is moved in a direction in which the axial distance from the drive cam 38 is reduced. As a result, the force for pressing the first friction plate 33 and the second friction plate 34 against each other is lost. As a result, due to the action of the return spring 35, the distance between the first friction plate 33 and the second friction plate 34 increases, and the friction engagement portion 29 is disconnected, so that the electric friction clutch device 11 switches to the disconnection mode.

[0319] On the other hand, when switching the electric friction clutch device 11a to the connection mode for transmitting torque between the rotating member 10a and the input member 8a, the drive cam 38 is rotationally driven by the electric actuator 32, and thereby the driven cam 39 is moved in a direction in which the axial distance from the drive cam 38 increases. As a result, the driven cam 39 presses the first friction plate 33 and the second friction plate 34 against each other via the elastic member 37a and the thrust bearing 61a in a direction in which they are pressed against each other. As a result, the first friction plate 33 and the second friction plate 34 are pressed against each other, and the friction engagement portion 29 is connected, whereby the electric friction clutch device 11a is switched to the connection mode.

[0320] In this example, when maintaining the connection mode of the electric friction clutch device 11a, it is necessary to continuously energize the shift motor 70. On the other hand, when maintaining the electric friction clutch device 11a in the disconnection mode, it is not necessary to continuously energize the shift motor 70. That is, the electric friction clutch device 11 in this example is configured by a normally open type clutch device.

[0321] In this example, the planetary gear mechanism 13a is configured by a single pinion type planetary gear mechanism. Further, in this example, the carrier 106a is connected to the output member 9a so as to rotate integrally with the output member 9a, the sun gear 104a is connected to the input member 8a so as to rotate integrally with the input member 8a, and the ring gear 105a is connected to the rotating member 10a so as to rotate integrally with the rotating member 10a.

[0322] Also in the drive device 1a for an electric vehicle of this example, the control device 6 has a reduction ratio switching function for switching the two-speed transmission 3a between a high reduction ratio mode in which the reduction ratio between the input member 8a and the output member 9a is large and a low reduction ratio mode in which the reduction ratio is small.

[0323] <Low reduction ratio mode> To switch the two-speed transmission 3a to the low reduction ratio mode, the electric friction clutch device 11a is switched to the connection mode. As a result, the input member 8a and the rotating member 10a rotate integrally, and the sun gear 104a and the ring gear 105a rotate integrally. Also, the rotation transmission state switching device 12a is switched to the free mode. As a result, the rotation of the rotating member 10a with respect to the fixed portion 14 is permitted, and the rotation of the ring gear 105a is permitted.

[0324] In the low reduction ratio mode, the rotation directions and rotation speeds of the sun gear 104a, the ring gear 105a, and the carrier 106a become the same, and the entire planetary gear mechanism 13a rotates integrally, which is a so-called mounted state. Therefore, the rotational torque of the input member 8a is transmitted in the order of the input member 8a, the carrier 106a, and the output member 9a and taken out from the output member 9 as shown by the thick line in FIG. 34(A).

[0325] <High reduction ratio mode> To switch the two-speed transmission 3a to the low reduction ratio mode, the electric friction clutch device 11a is switched to the disconnection mode. As a result, the input member 8a and the rotating member 10a can rotate relative to each other, and the sun gear 104a and the ring gear 105a can rotate relative to each other. Also, the rotation transmission state switching device 12a is switched to the lock mode. As a result, the rotation of the rotating member 10a with respect to the fixed portion 14 is blocked, and the rotation of the ring gear 105a is blocked.

[0326] In the high reduction ratio mode, the rotational torque of the input member 8a is transmitted in the order of the input member 8a, the sun gear 104a, the self-rotation of the planetary gear 107a, the revolution of the planetary gear 107a based on the meshing with the ring gear 105a, the carrier 106a, and the output member 9a and taken out from the output member 9a as shown in FIG. 34(B).

[0327] Also in this example, the two-speed transmission 3a can be switched to a reduction ratio switching mode, a neutral mode, and a parking mode.

[0328] The control device 6 has a torque passing through the two-speed transmission 3a from the side of the output member 9a toward the side of the input member 8a, and a torque is applied to the first member 74 to rotate the first member 74 in one circumferential direction with respect to the second member 75. Also, when the rotation of the first member 74 in one circumferential direction with respect to the second member 75 is blocked by the rotation transmission state switching device 12a, the control device 6 is provided with a cooperative control function that executes a pre-shift process of increasing the braking force by the friction braking device 5 while reducing the regenerative torque of the drive motor 2, before the second engaging claw 97 is radially pressed by the protruding portion 100 and retracted from the engaging recess 77, along with the mode switching of the two-speed transmission 3a by the reduction ratio switching function. Thereby, even during regenerative running in which regenerative torque acts on the drive motor 2, the mode switching of the rotation transmission state switching device 12a can be performed smoothly.

[0329] The configurations and the operational effects of the other parts for the second example are the same as those of the first example.

Explanation of Reference Numerals

[0330] 1, 1a Drive device for electric vehicle 2 Drive motor 3, 3a Two-speed transmission 4 Torque transmission mechanism 5 Friction braking device 6 Control device 7 Motor output shaft 8, 8a Input member 9, 9a Output member 10, 10a Rotating member 11, 11a Electric friction clutch device 12, 12a Rotation transmission state switching device 13, 13a Planetary gear mechanism 14 Fixed part 15 Driving gear 16 Input gear 17 Output gear 18 Small-diameter flange portion 19 Flange portion 20 Through hole 21 First ring portion 22 First cylindrical portion 23 Second annular part 24 Second cylindrical part 25 Shaft member 26 Step cylindrical member 27 Small-diameter cylindrical part 28 Female spline part 29 Frictional engagement part 30, 30a Elastic biasing mechanism 31, 31z Cam device 32 Electric actuator 33 First friction plate 34 Second friction plate 35 Return spring 36 Piston 37, 37a Elastic member 38, 38z Driving cam 39 Driven cam 40 Rolling element 41 Cylindrical member 42 Radial bearing 43 Angular ball bearing 44 Cylindrical part 45 Outer flange part 46 Inner ring 47 Outer ring 48 Rolling element 49 Inner ring 50 Outer ring 51 Ball 52 Driving cam surface 52a First bottom 52b Gentle inclined surface part 52c First flat surface part 52d Inclined surface part 52e Second bottom 52f First medium inclined surface part 52g Second flat surface part 52h Second medium inclined surface part 53 Wheel teeth 54 Pin part 55 Female spline part 56 Male spline part 57 Rectangular hole 58a, 58b Support plate part 59 Support hole 60 Support recess 61 and 61a thrust bearings 62 pressing member 63a, 63b, 63c, and 63d raceway wheels 64 rolling elements 65 preload applying means 66 base 67 partial cylindrical portion 68 support shaft 69 roller 70 shift motor 71 speed reducer 72 worm 73a and 73b support bearings 74 first member 75 second member 76 mode select member 77 engaging recess 78 convex portion 79 concavo-convex portion 80 outer diameter side concavo-convex engaging portion 81 inner diameter side concavo-convex engaging portion 82 inner diameter side concavo-convex engaging portion 83 base 84 cylindrical portion 85 first retaining recess 86 second retaining recess 87a and 87b spring retaining portions 88a and 88b pedestal portions 89 first claw member 90 second claw member 91 first claw biasing member 92 second claw biasing member 93 first base 94 first engaging claw 95 annular convex portion 96 second base 97 second engaging claw 98 base 99 plate side engaging hole 100 protruding portion 101 concavo-convex portion 102 lid 103 retaining ring 104 and 104a sun gears 105 and 105a ring gears 106 and 106a carriers 107 Planetary gear 108 Driving wheel 109 Drive shaft 110 Rotating body for braking 111 Accelerator opening sensor 112 Input rotation sensor 113 Output rotation sensor 114 TCU 115 Inverter 116 VCU 117 Ring gear 201 First friction engagement device 202 Second friction engagement device 203 First driven cam 204 Second driven cam

Claims

1. a drive motor having a motor output shaft; a two-speed transmission including an input member capable of transmitting torque between the input member and the motor output shaft, an output member supported so as to be rotatable relative to the input member, a rotating member supported so as to be rotatable relative to the input member and the output member, an electric friction clutch device, and a rotation transmission state switching device; a torque transmission mechanism that transmits torque between the output member and a drive wheel; a friction brake device disposed between the output member and the drive wheel for braking the rotation of the drive wheel; a control device; Equipped with The electric friction clutch device is a first clutch member that rotates integrally with the rotary member or is constituted by the rotary member itself; a second clutch member that is coaxial with the first clutch member, is supported so as to be rotatable relative to the first clutch member, and rotates integrally with the input member or the output member, or is constituted by the input member or the output member itself; a friction engagement portion provided between the first clutch member and the second clutch member, the friction engagement portion having at least one first friction plate and at least one second friction plate supported to allow relative displacement in the axial direction; a cam device including a drive cam and a driven cam supported so as to be capable of relative rotation and axial displacement with respect to the drive cam, the cam device expanding and contracting an axial distance between the drive cam and the driven cam as the drive cam rotates; an electric actuator having a shift motor and a reducer, the electric actuator rotatingly driving the drive cam by the shift motor via the reducer; and The cam device is configured to be switchable between a connection mode in which torque is transmitted between the first clutch member and the second clutch member by pressing the at least one first friction plate and the at least one second friction plate against each other based on expansion and contraction of the axial dimension thereof, and a disconnection mode in which torque is not transmitted between the first clutch member and the second clutch member by releasing the force pressing the at least one first friction plate and the at least one second friction plate against each other, The rotation transmission state switching device is a first member having engaging recesses at a plurality of locations in a circumferential direction; a second member disposed coaxially with the first member; a mode selector member having protrusions protruding in a radial or axial direction at a plurality of circumferential locations, the mode selector member rotating or displacing in the axial direction as the drive cam rotates; a first claw member having a first base portion pivotally supported on the second member and a first engagement claw extending from the first base portion toward a first side in a circumferential direction; a second claw member having a second base portion pivotally supported on the second member and a second engagement claw extending from the second base portion toward a second side in the circumferential direction; a first claw biasing member that elastically biases the first engagement claw in a direction to engage with the engagement recess; a second claw biasing member that elastically biases the second engagement claw in a direction to engage with the engagement recess; and One of the first member and the second member rotates integrally with the rotating member or is constituted by the rotating member itself, and the other of the first member and the second member is supported so as not to rotate relatively to a fixed part that does not rotate even during use, a lock mode in which the protrusion is positioned at a position deviated from the first engagement claw and the second engagement claw in the circumferential direction or the axial direction, and the first engagement claw and the second engagement claw are engaged with the engagement recesses, thereby preventing relative rotation between the first member and the second member regardless of the relative rotation direction between the first member and the second member; and a one-way clutch mode in which the protrusion presses only one of the first engagement claw and the second engagement claw in the radial direction or the axial direction, thereby retracting the first engagement claw and the second engagement claw from the engagement recesses, and engages the other engagement claw with the engagement recesses, thereby allowing rotation of the one member relative to the other member only in a predetermined direction and preventing rotation of the one member relative to the other member in a direction opposite to the predetermined direction; and a free mode in which the protrusion presses the first engagement claw and the second engagement claw in the radial direction or the axial direction, thereby retracting the first engagement claw and the second engagement claw from the engagement recesses, thereby allowing relative rotation between the first member and the second member regardless of the relative rotation direction between the first member and the second member. The control device a reduction ratio switching function that switches a mode of the electric friction clutch device and a mode of the rotation transmission state switching device based on the rotational driving of the drive cam by the electric actuator, thereby switching the two-stage transmission between a high reduction ratio mode in which the reduction ratio between the input member and the output member is large and a low reduction ratio mode in which the reduction ratio between the input member and the output member is small; and a cooperative control function of executing a pre-shift process in which, in a state in which torque passes through the two-stage transmission from the output member side toward the input member side, torque is applied to one of the members tending to rotate the one of the members toward one circumferential side relative to the other member, and the rotation of the one of the members toward one circumferential side relative to the other member is prevented by the rotation transmission state switching device, in response to a mode switching of the two-stage transmission by the reduction ratio switching function, the cooperative control function executes a pre-shift process in which the regenerative torque of the drive motor is reduced while increasing the braking force of the friction brake device, before one of the first engagement pawls and the second engagement pawls extending from a base pivotally supported on the second member toward the other circumferential side is pressed radially or axially by the protruding portion to retract from the engagement recess. Drive unit for electric vehicles.

2. 2. The electric vehicle drive system according to claim 1, wherein the regenerative torque of the drive motor is reduced to zero in the pre-shifting step.

3. the two-speed transmission is configured to be switchable to the lock mode, 2. The electric vehicle drive device according to claim 1, wherein the reduction ratio switching function switches the two-stage transmission to the high reduction ratio mode by switching the electric friction clutch device to the disengagement mode and the rotation transmission state switching device to the lock mode, and switches the two-stage transmission to the low reduction ratio mode by switching the electric friction clutch device to the engagement mode and the rotation transmission state switching device to the free mode.

4. the two-speed transmission is configured to be switchable to the one-way clutch mode, 4. The electric vehicle drive device according to claim 3, wherein the control device executes the cooperative control function while the two-stage transmission is being switched from the high reduction ratio mode to the low reduction ratio mode and before the rotation transmission state switching device is switched from the lock mode to the one-way clutch mode.

5. 5. The electric vehicle drive device according to claim 4, wherein the cooperative control function performs the pre-shift process, and further performs an inertia process of reducing the drive torque of the drive motor by increasing the drive torque of the drive motor in the same direction as the direction of the regenerative torque acting on the drive motor after performing the pre-shift process and retracting the one of the engagement pawls from the engagement recess by using the protrusion in the radial or axial direction.

6. 6. The electric vehicle drive device according to claim 5, wherein the cooperative control function, after carrying out the inertia process, adjusts the fastening force of the friction engagement portion to a magnitude such that a torque that can be transmitted without slippage between the at least one first friction plate and the at least one second friction plate is equal to or greater than a torque that passes through the friction engagement portion after completion of switching of the two-stage transmission to the low reduction ratio mode, and thereafter carries out a shift completion process in which the braking force of the friction brake device is reduced while the regenerative torque of the drive motor is increased.

7. 2. The electric vehicle drive device according to claim 1, wherein the electric friction clutch device includes a return spring that elastically biases the at least one first friction plate and the at least one second friction plate in a direction separating them from each other.

8. 2. The electric vehicle drive device according to claim 1, wherein the electric friction clutch device further comprises an elastic biasing mechanism provided between the first clutch member or the second clutch member and the friction engagement portion, and elastically biasing the at least one first friction plate and the at least one second friction plate in a direction pressing them against each other.

9. 2. The electric vehicle drive device according to claim 1, wherein the electric friction clutch device further comprises an elastic biasing mechanism that is disposed between the friction engagement portion and the driven cam and that elastically biases the friction engagement portion and the driven cam in directions away from each other.

10. The two-speed transmission further includes a planetary gear mechanism including a sun gear, a ring gear arranged coaxially around the sun gear, a carrier supported to be rotatable relative to the sun gear and the ring gear, and a plurality of planetary gears meshed with the sun gear and the ring gear and supported by the carrier to be rotatable about their own central axes, an input element, which is any one of the sun gear, the ring gear, and the carrier, is connected to the input member so as to rotate integrally with the input member; an output element, which is one of the sun gear, the ring gear, and the carrier and is an element separate from the input element, is connected to the output member so as to rotate integrally with the output member; 10. The electric vehicle drive device according to claim 1, wherein rotating elements, which are the remaining elements of the sun gear, the ring gear, and the carrier excluding the input element and the output element, are connected to the rotating member so as to rotate integrally with the rotating member.

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