Electric vehicle drive device

Abstract

This electric vehicle drive device is capable of switching the reduction ratio between two stages of high and low, wherein a structure is realized in which a rotary transmission state switching device can smoothly switch modes even during regenerative travel in which regenerative torque acts on a drive motor.　A control device of the electric vehicle drive device is provided with a cooperative control function for executing, in association with the mode switching of a two-stage transmission (3) by a reduction ratio switching function, a pre-shift step for increasing the braking force from a friction brake device (5) while reducing the regenerative torque of a drive motor (2) before one engagement claw (94 (or 97)), between a first engagement claw (94) and a second engagement claw (97), that extends from a base (93 (or 96)) pivotally supported by a second member (75) toward the other side in the circumferential direction is pressed in the radial direction or the axial direction by a protrusion (100) so as to retreat from an engagement recess (77).

Description

Electric vehicle drive unit

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

[0002] In response to the recent trend toward reducing fossil fuel consumption, research into electric vehicles and hybrid vehicles has progressed, and some have already been implemented. Unlike internal combustion engines, which are powered by directly burning fossil fuels, electric motors, which are the power source for electric vehicles and hybrid vehicles, have output shaft torque and rotational speed characteristics that are favorable for automotive use (generally, maximum torque is generated at startup), so they do not necessarily need to be equipped with a transmission like ordinary vehicles powered by internal combustion engines.

[0003] However, even when an electric motor is used as the drive source, the provision of a transmission can improve acceleration and high-speed performance. Specifically, the provision of a transmission can make the relationship between the vehicle's running speed and acceleration smoother, similar to that of a vehicle equipped with a gasoline engine and a transmission in its power transmission system. This point will be explained with reference to FIG. 36.

[0004] For example, if a power transmission device with a large reduction ratio is placed between the output shaft of an electric motor and the input part of a differential gear connected to the drive wheels, the relationship between the acceleration (G) and running speed (km / h) of the electric vehicle will be as shown by the solid line a in Figure 36. In other words, the electric vehicle will have excellent acceleration performance at low speeds, but will not be able to run at high speeds. In contrast, if a power transmission device with a small reduction ratio is placed between the output shaft and the input part, the relationship will be as shown by the dotted line b in Figure 36. In other words, the electric vehicle will be able to run at high speeds, but its acceleration performance at low speeds will be impaired.

[0005] In contrast to this, 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, a characteristic can be obtained in which the portion of the solid line a to the left of point P is continuous with the portion of the chain line b to the right of point P. This characteristic is roughly equivalent to that of a gasoline engine vehicle with a similar output, shown by the dashed line c in Figure 36, and it can be seen that in terms of acceleration performance and high-speed performance, performance equivalent to that of a gasoline engine vehicle with a transmission provided in the power transmission system can be obtained.

[0006] International Publication No. 2023 / 135870 discloses a structure of a drive unit for an electric vehicle in which the output torque of a drive motor, which is a drive source, is increased by a two-stage transmission including a friction engagement device switchable between an engagement mode and a disengagement mode, and a rotation transmission state switching device switchable between a lock mode, a one-way clutch mode, and a free mode, and then transmitted to a differential gear. In this electric vehicle drive unit, by switching the mode of the friction engagement device and the mode of the rotation 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 a disconnection mode and the rotation transmission state switching device to a lock mode, the two-speed transmission can be switched to a high reduction ratio mode, and by switching the electric friction clutch device to a connection mode and the rotation transmission state switching device to a free mode, the two-speed transmission can be switched to a low reduction ratio mode.

[0008] In the electric vehicle drive system described in WO 2023 / 135870, when switching from a high reduction ratio mode to a low reduction ratio mode during normal forward running (power running), the rotation transmission state switching device is switched from a lock mode to a one-way clutch mode, and then the friction engagement device is switched from a disengagement mode to an engagement mode, thereby preventing the occurrence of shock (shift shock) when switching the reduction ratio.

[0009] The rotation transmission state switching device that constitutes this electric vehicle drive device includes a first member, a second member, a mode select member, a first pawl member, a second pawl member, a first pawl biasing member, and a second pawl biasing member.

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

[0011] The second member is disposed around and coaxial with the first member.

[0012] The mode select member has a plurality of radially protruding projections at circumferential locations, and rotates in conjunction with the rotation of a drive cam for switching the friction clutch device.

[0013] The first claw member has 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 the circumferential direction.

[0014] The second claw member has a second base portion pivotally supported on the second member, and a second engagement claw extending 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 pawl biasing member elastically biases the second engagement pawl in a direction to engage with the engagement recess.

[0017] This rotation transmission state switching device switches between a free mode, a lock mode, and a one-way clutch mode in accordance with the rotation of the mode select member.

[0018] Specifically, when the rotation transmission state switching device is switched to free mode, the mode select member is rotated and the protrusion pushes the first engagement claw and the second engagement claw radially outward and retracts them from the engagement recess, thereby allowing rotation of the first member relative to the second member regardless of the relative rotation direction between the first member and the second member.

[0019] When the rotation transmission state switching device is switched to the lock mode, the protrusion is positioned at a position circumferentially offset from the first engagement claw and the second engagement claw, and the first engagement claw and the second engagement claw are engaged with the engagement recess, thereby preventing rotation of the first member relative to the second member regardless of the relative rotation direction between the first member and the second member.

[0020] When the rotation transmission state switching device is switched to one-way clutch mode, the protrusion pushes only the second engagement claw radially outward and retracts it from the engagement recess, thereby allowing only rotation of the first member in a specified direction relative to the second member and preventing rotation in the direction opposite to the specified direction.

[0021] WO 2023 / 135870

[0022] In the electric vehicle drive device described in WO 2023 / 135870, when switching from high reduction ratio mode to low reduction ratio mode during regenerative driving in which regenerative torque acts on the drive motor, it is necessary to switch the rotation transmission state switching device from lock mode to one-way clutch mode and then to free mode.

[0023] When the vehicle is traveling forward in a high reduction ratio mode, torque is applied to the first member in a direction opposite to the predetermined direction, i.e., in a direction that prevents rotation by the rotation transmission state switching device. As a result, the circumferential side surface of the engagement recess provided in the first member is pressed strongly against the tip of the first engagement pawl. Therefore, the force required to press the first engagement pawl radially outward by the protrusion to switch the rotation transmission state switching device from the lock mode to the one-way clutch mode may be excessive. In severe cases, the mode of the rotation transmission state switching device may not be switched.

[0024] If a high-output motor is used as the shift motor that rotates 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 forward regenerative driving in high reduction ratio mode, but this creates the problem of the shift motor becoming larger.

[0025] In view of the above-mentioned circumstances, the present disclosure aims to realize a structure for an electric vehicle drive device capable of switching the reduction ratio between two levels, high and low, that enables smooth mode switching when switching from a low reduction ratio mode to a high reduction ratio mode during regenerative driving in which regenerative torque acts on the drive motor.

[0026] An electric vehicle drive system according to one aspect of the present disclosure includes a drive motor, a two-speed 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-speed transmission includes an input member, an output member, a rotating member, an electric friction clutch device, and a rotation transmission state switching device.

[0029] The input member is capable of transmitting torque between itself and the motor output shaft.

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

[0031] The rotation 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 rotary member, or is formed by the rotary member itself.

[0034] 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, 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 has at least one first friction plate and at least one second friction plate supported to allow relative axial displacement, and is provided between the first clutch member and the second clutch member.

[0036] The cam device has a drive cam and a driven cam supported to be able to rotate relative to the drive cam and to be displaced axially relative to the drive cam. The cam device expands and contracts the axial distance between the drive cam and the driven cam as the drive cam rotates.

[0037] The electric actuator has a shift motor and a reducer, and the drive cam is rotationally driven by the shift motor via the reducer.

[0038] The electric friction clutch 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 expanding and 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 rotation transmission state switching device includes a first member, a second member, a mode select member, a first pawl member, a second pawl member, a first pawl biasing member, and a second pawl biasing member.

[0040] The first member has a plurality of engaging recesses at circumferential positions.

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

[0042] The mode select member has protrusions that protrude radially or axially at a plurality of circumferential locations, and rotates or displaces axially as the drive cam rotates.

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

[0044] The second claw member has a second base portion pivotally supported by the second member, and a second engaging claw extending from the second base portion toward a 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, and the other of the first member and the second member is supported non-rotatably relative 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] The locking mode positions the protrusion at a position circumferentially or axially offset from the first engagement claw and the second engagement claw, and engages the first engagement claw and the second engagement claw with the engagement 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 protrusion presses only one of the first and second engagement claws radially or axially to retract it from the engagement recess, and engages the other engagement claw with the engagement recess, thereby allowing only rotation of the one member in a predetermined direction relative to the other member and preventing rotation of the one member in the direction opposite to the predetermined direction relative to the other member.

[0051] The free mode allows relative rotation between the first member and the second member regardless of the relative rotation direction between the first member and the second member by using the protrusion to press the first engagement claw and the second engagement claw radially or axially and retract them from the engagement recess.

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

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

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

[0055] The reduction ratio switching function switches the mode of the friction engagement portion and the 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-speed 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.

[0056] The cooperative control function is in a state where torque is passing through the two-speed transmission from the output member side toward the input member side, a torque is applied to one of the members that tends to rotate the one member toward one circumferential side relative to the other member, and the rotation transmission state switching device prevents the one member from rotating toward one circumferential side relative to the other member, and when the mode of the two-speed transmission is switched by the reduction ratio switching function, a pre-shift process is executed in which the regenerative torque of the drive motor is reduced while the braking force of the friction brake device is increased before one of the first engagement claw and the second engagement claw that extends toward the other circumferential side from a base pivotally supported on the second member is pressed radially or axially by the protrusion to retract from the engagement recess.

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

[0058] In the electric vehicle drive device according to the first aspect of the present disclosure, the two-stage transmission can be configured to be switchable to the locked mode. In this case, the reduction ratio switching function can switch the two-stage transmission to the high reduction ratio mode by switching the electric friction clutch device to the disengaged mode and the rotation transmission state switching device to the locked mode, and can switch the two-stage transmission to the low reduction ratio mode by switching the electric friction clutch device to the engaged mode and the rotation transmission state switching device to the free mode.

[0059] In the electric vehicle drive system according to one aspect of the present disclosure, the two-stage transmission may be configured to be switchable to the one-way clutch mode, and in this case, the cooperative control function may be executed 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.

[0060] In one aspect of the electric vehicle drive device of the present disclosure, the cooperative control function performs the pre-shift process, and further presses one of the engagement claws radially or axially with the protrusion to retract it from the engagement recess, and then 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 rotation speed of the motor output shaft, and then, when the rotation speed of the motor output shaft begins to decrease, performs an inertia process to reduce the drive torque of the drive motor.

[0061] In the electric vehicle drive device of one aspect of the present disclosure, the cooperative control function, after performing the inertia process, adjusts the fastening force of the friction engagement portion to a magnitude such that the 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 the torque that passes through the friction engagement portion after the two-stage transmission has completely switched to the low reduction ratio mode, and thereafter executes a shift completion process that increases the regenerative torque of the drive motor while reducing the braking force of the friction brake device.

[0062] In one aspect of the electric vehicle drive device 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 separating them from each other.

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

[0064] Alternatively, in an electric vehicle drive device according to one aspect of the present disclosure, the electric friction clutch device may further include 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.

[0065] In one aspect of the electric vehicle drive device of the present disclosure, the two-speed transmission can further include a planetary gear mechanism having a sun gear, a ring gear arranged coaxially around the sun gear, a carrier supported to be able to rotate 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 on the carrier to be able to rotate around their own central axes.

[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 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.

[0068] Of the sun gear, the ring gear, and the carrier, the remaining rotating elements excluding the input element and the output element are connected to the rotating member so as to rotate integrally with the rotating member.

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

[0070] FIG. 1 is a block diagram showing an electric vehicle drive device according to a first example of an embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically showing the electric vehicle drive device according to the first example. FIG. 3(A) is a diagram showing a torque transmission path in a low reduction ratio mode of a two-speed transmission according to the first example, and FIG. 3(B) is a diagram showing a torque transmission path in a high reduction ratio mode of the two-speed transmission according to the first example. FIG. 4 is a perspective view showing the two-speed transmission according to the first example. FIG. 5 is a cross-sectional view showing the two-speed transmission according to the first example. FIG. 6 is a perspective view showing the two-speed transmission according to the first example with the planetary gear mechanism removed. FIG. 7 is a cross-sectional view showing the two-speed transmission according to the first example with the planetary gear mechanism removed. FIG. 8 is an exploded perspective view showing the two-speed transmission according to the first example with the planetary gear mechanism removed. FIG. 9 is an exploded perspective view showing a worm and two support bearings removed from the electric friction clutch device constituting the two-speed transmission in the first example. FIG. 10 is an exploded perspective view showing a first friction plate and a second friction plate removed from the electric friction clutch device in the first example. FIG. 11 is an enlarged view of the X portion in FIG. 5. FIG. 12 is an oblique view showing a drive cam removed from the electric friction clutch device in the first example. FIG. 13 is an exploded perspective view showing a driven cam and rolling elements removed from the electric friction clutch device in the first example. FIG. 14(A) is an oblique view showing a flange portion and a pressing member of a rotating member removed from the two-speed transmission in the first example, and FIG. 14(B) is an exploded perspective view showing the flange portion and the pressing member removed. FIGS. 15(A) to 15(D) are schematic views of the cam device of the electric friction clutch device as viewed from the radial outside. Fig. 16 is a perspective view of the rotation transmission state switching device constituting the two-speed transmission according to the first example, as seen from the other axial side. Fig. 17 is an exploded perspective view of the rotation transmission state switching device according to the first example. Fig. 18 is an end view of the rotation transmission state switching device according to the first example, as seen from the other axial side with the cover removed. Fig. 19 is an enlarged view of part Y in Fig. 18.Fig. 20(A) is a schematic diagram showing the engagement relationship between the first engagement pawl and the second engagement pawl and the engagement recess and the protrusion in the free mode of the rotation transmission state switching device for the first example, Fig. 20(B) is a schematic diagram showing the engagement relationship in the locked mode, and Fig. 20(C) is a schematic diagram showing the engagement relationship in the one-way clutch mode. Fig. 21 is a diagram showing the mode of the electric friction clutch device and the mode of the rotation transmission state switching device in the two-speed transmission for the first example. Figs. 22(A) and 22(B) are diagrams showing the relationship between the rotation angle of the drive cam and the output torque and current value of the shift motor when the electric friction clutch device is switched from the engaged mode to the disengaged mode for the first example. Fig. 22(A) shows the case where the first friction plate and the second friction plate are new and not worn, and Fig. 22(B) shows the case where the first friction plate and the second friction plate have significantly advanced wear. FIG. 23 is a cross-sectional view showing a state in which the electric friction clutch device has been switched to the connection mode for the first example. FIG. 24 is a cross-sectional view showing a state in which the pressing member and the piston are in contact with each other during switching of the electric friction clutch device from the connection mode to the disconnection mode for the first example. FIG. 25 is a cross-sectional view showing a state in which the electric friction clutch device has been switched to the disconnection mode for the first example. FIG. 26 is a flowchart showing the operation of the two-stage transmission when switching from the high reduction ratio mode to the low reduction ratio mode during normal forward traveling for the first example. FIG. 27 is a diagram showing the time changes of each parameter when switching the two-stage transmission from the high reduction ratio mode to the low reduction ratio mode during normal forward traveling for the first example. FIG. 28 is a flowchart showing the operation of the two-stage transmission when switching from the high reduction ratio mode to the low reduction ratio mode during regenerative traveling in which regenerative torque is acting on the drive motor for the first example. Fig. 29 is a diagram showing the time variations of each parameter when the two-speed transmission is switched from the high reduction ratio mode to the low reduction ratio mode during the regenerative running for the first example. Fig. 30 is a cross-sectional view showing a part of the two-speed transmission of the comparative example. Fig. 31 is a diagram showing a schematic diagram of the engagement and disengagement states of the first friction engagement device and the second friction engagement device for the two-speed transmission of the comparative example.Fig. 32 is a diagram corresponding to Fig. 21 and illustrating a two-speed transmission that is a modified example of the first example. Fig. 33 is a cross-sectional view that schematically illustrates an electric vehicle drive system of a second example of an embodiment of the present disclosure. Fig. 34(A) is a diagram illustrating a torque transmission path in a low reduction ratio mode of a two-speed transmission that constitutes the electric vehicle drive system of the second example, and Fig. 34(B) is a diagram illustrating a torque transmission path in a high reduction ratio mode of the two-speed transmission of the second example. Fig. 35 is a cross-sectional view that illustrates the two-speed transmission of the second example. Fig. 36 is a diagram for explaining the effect of incorporating a transmission into a drive system that uses an electric motor as a drive source.

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

[0072] The electric vehicle drive system 1 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] The torque of the drive motor 2 (T ２ ) is positive means that it is an output torque (driving torque, power torque), and ２ In the following description, a positive value of torque (T ２ ) is expressed as the output torque, and the torque with a negative value (T ２ ) is sometimes referred to as 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 rotation transmission state switching device 12 .

[0076] With respect to the two-speed transmission 3, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the input member 8, unless otherwise specified. 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. Furthermore, one axial side refers to the right side in Figures 2, 3(A), 3(B), 5, 7, 11, 15(A) to 15(D), and 23 to 25, and the other axial side refers to the left side in Figures 2, 3(A), 3(B), 5, 7, 11, 15(A) to 15(D), and 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 torque transmission path by switching between the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12. In this example, the two-speed transmission 3 switches between the high reduction ratio mode and the low reduction ratio mode by switching the torque transmission path passing through the planetary gear mechanism 13, by switching between the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12.

[0078] The input member 8 is capable of transmitting torque between itself and the motor output shaft 7. Specifically, the input member 8 has, at one axial end thereof, an input gear 16 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 rotatably supported by a rolling bearing (not shown) or the like with respect to a fixed part 14 that does not rotate even during use and is constituted by a housing or the like that accommodates the two-speed transmission 3. The input member 8 is also cylindrical (hollow).

[0080] The output member 9 is supported so as to be rotatable relative to the input member 8 .

[0081] In this example, the output member 9 is disposed coaxially with the input member 8 and is supported radially inside the cylindrical input member 8 via a rolling bearing (not shown) or the like so as to be rotatable relative to the input member 8. The output member 9 also has an output gear 17 at one end in the axial direction.

[0082] The rotary member 10 is supported so as to be rotatable relative 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 relative to the fixed part 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 the drive cam 38 that constitutes the cam device 31 relative to the rotating member 10.

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

[0085] In this example, the rotating member 10 is constructed 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 Figures 14(A) and 14(B), the stepped cylindrical member 26 has a flange portion 19 and a small-diameter cylindrical portion 27 that is bent from the radially inner end of the first annular portion 21 of the flange portion 19 toward the other axial direction. The rotating member 10 is constructed by supporting and fixing the stepped cylindrical member 26 to the shaft member 25, for example, 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 also be constructed by connecting 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 an engagement mode in which torque is transmitted between the first clutch member and the second clutch member, and a disengagement mode in which torque is not transmitted.

[0087] The first clutch member is connected to the rotating member 10 so as 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 rotatable relative to the first clutch member. The second clutch member is connected to the input member 8 or the output member 9 so as to rotate integrally therewith, 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 allow relative axial displacement, 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 made up of a plurality of first friction plates 33, and at least one second friction plate 34 is made up of a plurality of second friction plates 34. More specifically, the friction engagement portion 29 is made up of 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 capable of axial displacement but not capable of relative rotation with respect to the first cylindrical portion 22 .

[0092] The plurality of second friction plates 34 are supported on the inner peripheral surface of the other axial end of the input member 8 so as to be capable of axial displacement but not capable of relative rotation with respect to the input member 8 .

[0093] The cam device 31 has a driving cam 38 and a driven cam 39 that is supported so as to be capable of relative rotation and axial displacement relative to the driving cam 38. The cam device 31 increases or decreases the axial distance between the driving cam 38 and the driven cam 39 as the driving cam 38 rotates.

[0094] Cam device 31 may have any configuration as long as the axial distance between drive cam 38 and driven cam 39, i.e., the axial dimension of cam device 31, can be increased or decreased in accordance with the rotation of drive cam 38. For example, the cam device may have a configuration in which a drive cam surface provided on the drive cam and a driven cam surface provided on the driven cam directly slide against each other, a configuration in which multiple 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 multiple rolling elements supported on one of the drive cam and the driven cam are in rolling contact with the cam surface provided on the other of the drive cam and the driven cam.

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

[0096] The drive cam 38 is supported relative to the rotating member 10 so as to be rotatable relative to the rotating member 10 and the input member 8, but so as not to be displaceable in the axial direction relative to the rotating member 10. Specifically, as shown in Fig. 5 and other figures, 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 rotatable relative to the rotating member 10. Note that the cylindrical member 41 and the angular ball bearing 43 are not shown in Figs. 2 to 3(B).

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

[0098] The radial bearing 42 has an inner ring 46 fitted and fixed to the outside of the other axial end of the rotating member 10, an outer ring 47 fitted and fixed to the inside of the cylindrical portion 44 of the tubular member 41, and a plurality of rolling elements 48 arranged to roll freely between the inner ring 46 and the outer ring 47. In the example shown, the radial bearing 42 is configured as a double-row deep groove ball bearing that uses balls as the rolling elements 48. However, the radial bearing is not particularly limited as long as it allows relative rotation between the first member and the cam device and can support the axial biasing force of the elastic biasing mechanism, and can also be configured as, for example, a deep groove ball bearing, a radial angular contact ball bearing, or a radial tapered roller bearing.

[0099] The angular ball bearing 43 has an inner ring 49 fitted and fixed to the outside of the cylindrical portion 44 of the tubular member 41, an outer ring 50 fitted and fixed to the inside of the drive cam 38, and a plurality of balls 51 arranged freely rotatably 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 on the radially inner side of one axial side surface, in which the same number of recesses and protrusions are alternately arranged in the circumferential direction. The drive cam surface 52 is arranged in the following order from top to bottom in Figs. 15(A) to 15(D): a first bottom portion 52a, a gently inclined surface portion 52b, a first flat surface portion 52c, an inclined surface portion 52d, a second bottom portion 52e, a first intermediate inclined surface portion 52f, a second flat surface portion 52g, and a second intermediate inclined surface portion 52h. These portions are repeated the same number of times as the number of rolling elements 40 (three times in this example).

[0101] Of the drive cam surface 52, the first flat surface portion 52c and the second flat surface portion 52g are located closest to one side in the axial direction, i.e., at the tip of the convex portion, and the first bottom portion 52a and the second bottom portion 52e are located closest to the other side in the axial direction. The inclination angles of the first intermediate inclined surface portion 52f and the second intermediate inclined surface portion 52h with respect to an imaginary plane P perpendicular to the central axis of the drive cam 38 are larger than that of the gently inclined surface portion 52b with respect to the imaginary plane P.

[0102] The inclination angle of the gentle inclined surface portion 52b and the inclination angles of the first and second intermediate inclined surface portions 52f, 52h are all set to a magnitude that allows the rolling elements 40 to move in a rolling-down manner or a climbing-up manner. Note that in this example, the first intermediate inclined surface portion 52f and the second intermediate inclined surface portion 52h are inclined in opposite directions and have the same inclination angle, but the inclination angles can also be different. Also, in this example, the inclination angle of the gentle inclined surface portion 52b is smaller than the inclination angles of the first intermediate inclined surface portion 52f and the second intermediate inclined surface portion 52h, but the inclination angle of the gentle inclined surface portion 52b and the inclination angles of the first intermediate inclined surface portion 52f and the second intermediate inclined surface portion 52h can also be set to be the same.

[0103] The inclination angle of the inclined surface portion 52d with respect to the imaginary plane P can be set to any value as long as the rolling element 40 can ride up on it.

[0104] In this example, the drive cam 38 has wheel teeth 53, which are helical gears, on its outer surface, and also has pin portions 54 that protrude toward one axial side at multiple circumferential locations (three locations in the illustrated example) in the radially middle part of the side surface on one axial side.

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

[0106] 13, driven cam 39 has rectangular holes 57 penetrating in the axial direction at a plurality of circumferential locations (three locations in the illustrated example) in a radially intermediate portion, and has support plate portions 58a, 58b each having a substantially semicircular plate shape that protrudes toward the other axial direction from both radially opposite sides of rectangular hole 57. Of support plate portions 58a, 58b, the radially outer support plate portion 58a has a support hole 59 that is a circular hole penetrating in the radial direction, and radially inner support plate portion 58b has a support recess 60 with a circular opening on its radially outer surface.

[0107] In this example, the plurality of rolling elements 40 is made up of three rolling elements 40. However, the plurality of rolling elements 40 may also be made up of two or four or more rolling elements 40.

[0108] Each rolling element 40 has a cylindrical shape and is rotatably supported by the support plate portions 58a, 58b via a columnar support shaft 68 and a plurality of rollers 69. That is, the outer end of the support shaft 68 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 the inner end of the support shaft 68 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 rollably sandwiched between the inner peripheral surface of the rolling element 40 and the outer peripheral surface of the axially middle portion of the support shaft 68. As a result, the rolling element 40 is supported by the driven cam 39 so as to be able to rotate (spin) about a rotation axis C oriented in the radial direction centered on the central axis of the driven cam 39.

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

[0110] The cam device 31 drives the driving cam 38 to rotate, and increases or decreases the amount of the rolling body 40 that rides over the first bottom 52a or the second bottom 52e of the driving cam surface 52, thereby moving the driven cam 39 in the axial direction and expanding or contracting the axial distance between the driving cam 38 and the driven cam 39, i.e., the axial dimension of the cam device 31.

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

[0112] In this example, the reducer 71 is a worm reducer. That is, the 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 relative to the fixed part 14 by a pair of support bearings 73 a, 73 b. However, the reducer 71 can also be formed by meshing a spur gear or bevel gear provided on the output shaft of the electric motor with a spur gear or bevel gear provided on the drive cam, or by stretching a belt or 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 and 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 driving cam 38 is rotationally driven by the electric actuator 32, and the axial dimension of the cam device 31, i.e., the axial distance between the driving cam 38 and the driven cam 39, is increased, thereby pressing the first friction plate 33 and the second friction plate 34 against each other, and the axial dimension of the cam device 31 is reduced, thereby releasing the force pressing the first friction plate 33 and the second friction plate 34 against each other.

[0115] The electric friction clutch device 11 may further include, as an optional component, an elastic biasing mechanism 30 that 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 that elastically biases the first friction plate 33 and the second friction plate 34 in a direction pressing them against each other.

[0116] In this case, the electric friction clutch device 11 is configured so that, based on the relative displacement of the driven cam 39 in a direction that increases the axial distance between it and the driving cam 38, the driven cam 39 presses the elastically biasing mechanism 30 in a direction that releases the force pressing the first friction plate 33 and the second friction plate 34 against each other, and based on the relative displacement of the driven cam 39 in a direction that decreases the axial distance between it and the driving cam 38, the elastically biasing mechanism 30 presses the first friction plate 33 and the second friction plate 34 against each other.

[0117] Alternatively, the electric friction clutch device 11 may further include, as an optional component, an elastic biasing mechanism that is arranged between the friction engagement portion 29 and the driven cam 39 and elastically biases the friction engagement portion 29 and the driven cam 39 in directions away from each other.

[0118] In this case, the electric friction clutch device 11 is configured so that the driven cam 39 presses the first friction plate 33 and the second friction plate 34 toward each other via the elastic biasing mechanism 30 based on the relative displacement of the driven cam 39 in the direction of increasing the axial distance between it and the driving cam 38, and so that the force pressing the first friction plate 33 and the second friction plate 34 toward each other is released based on the relative displacement of the driven cam 39 in the direction of decreasing the axial distance between it and the driving cam 38.

[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 is equipped with an elastic biasing mechanism 30 that elastically biases the first friction plate 33 and the second friction plate 34 in a direction pressing them against each other.

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

[0121] The piston 36 is supported so as to be movable in the axial direction relative to the rotating member 10. The piston 36 is configured in the shape of a hollow circular plate, and is supported around a portion of the rotating member 10 between the small diameter flange portion 18 and the flange portion 19 in the axial direction so as to be movable in the axial direction relative to the rotating member 10. The end face on the other axial side of the radially outer portion of the piston 36 faces a side face on one axial side of the first friction plate 33 or the second friction plate 34 that is located furthest axially to one 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 a side surface on the other axial direction side of the small-diameter flange portion 18 of the rotating member 10 and a side surface on one axial direction side of the piston 36. In other words, the elastic biasing mechanism 30 elastically biases the first friction plate 33 or the second friction plate 34 closest to one axial direction side toward the other axial direction via the piston 36 by the force of the elastic member 37 attempting to elastically restore its original shape.

[0123] The specific configuration of the elastic member is not particularly limited. In this example, the elastic member 37 is configured by at least one disc spring, two disc springs in the illustrated example. However, the elastic member may also be configured by 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 a pressing member 62 disposed opposite the piston 36 and the driven cam 39 of the cam device 31. The thrust bearing 61 has a pair of raceways 63 a, 63 b and a plurality of rolling elements 64 disposed to roll freely between the pair of raceways 63 a, 63 b. Of the pair of raceways 63 a, 63 b, the raceway 63 b on the other axial side is supported and fixed to the driven cam 39.

[0126] The pressing member 62 has a cylindrical base 66 and partial cylindrical portions 67 that protrude toward one axial direction from multiple locations (three locations in the illustrated example) around the circumference of one axial end of the base 66. One axially facing raceway 63a of a pair of raceways 63a, 63b of the thrust bearing 61 is supported and fixed to the other axial end of the base 66. The partial cylindrical portion 67 is inserted into the through-hole 20 of the rotating member 10, and the tip end (the end on one axial side) of the partial cylindrical portion 67 faces a radially intermediate portion of the side surface on the other axial side of the piston 36.

[0127] The preload applying means 65 is disposed between the pressing member 62 and the rotating member 10 and applies a preload to the thrust bearing 61. The preload applying means 65 is sandwiched in an elastically compressed state between the pressing member 62 and the other axial side surface of the first circular ring portion 21 of the flange portion 19 constituting the rotating member 10. As a result, even when the piston 36 is pressed toward one axial side against the elastic restoring force of the elastic member 37 as shown in FIG. 3(B), a preload is applied to the thrust bearing 61 and the thrust bearing 61 is prevented from falling out from between the elastic biasing mechanism 30 and the cam device 31. The elasticity of the preload applying means 65 is smaller than the elastic restoring force of the elastic member 37. The preload applying means 65 can be configured, for example, by an elastic member such as an elastomer, e.g., rubber, or one or more disc springs, one or more coil springs, or other springs.

[0128] The electric friction clutch device 11 of this example includes, as an optional component, a return spring 35 that is disposed between the first friction plates 33 and the second friction plates 34 and elastically biases the first friction plates 33 and the second friction plates 34 in a direction that widens the gap between them. This ensures that the first friction plates 33 and the second friction plates 34 are separated from each other when the force pressing the first friction plates 33 and the second friction plates 34 against each other is released. 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 rotates the drive cam 38 using the electric actuator 32, expanding and contracting the axial dimension of the cam device 31, and displacing the piston 36 of the elastic driving mechanism 30 axially relative to the rotating member 10, thereby making it possible to switch 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 the electric friction clutch device 11 is switched to a disconnection mode in which torque is not transmitted between the rotating member 10 and the input member 8, the driving cam 38 is rotationally driven by the electric actuator 32, so that the rolling body 40 is positioned on the first flat surface portion 52c or the second flat surface portion 52g of the driving cam surface 52, or the amount of riding on the gentle slope surface portion 52b, the slope surface portion 52d, the first medium slope surface portion 52f, or the second medium slope surface portion 52h is increased, as shown in Figures 15(B) and 15(D).

[0131] As a result, by moving the driven cam 39 in one axial direction, which is a direction in which the axial distance between the driving cam 38 increases, the piston 36 of the elastically biasing mechanism 30 is pressed in one axial direction via the thrust bearing 61 and the pressing member 62, and the elastic member 37 is elastically compressed. When the elastic member 37 is elastically compressed, the force pressing the first friction plate 33 and the second friction plate 34 against each other decreases and is eventually lost. As a result, the distance between the first friction plate 33 and the second friction plate 34 increases due to the action of the return spring 35, and the friction engagement portion 29 is disengaged, and the electric friction clutch device 11 switches to the disengagement mode.

[0132] In contrast, when the electric friction clutch device 11 is switched to a connection mode in which torque is transmitted between the rotating member 10 and the input member 8, the electric actuator 32 rotates and drives the drive cam 38, so that the rolling body 40 is positioned at the first bottom 52a or the second bottom 52e of the drive cam surface 52, or the amount of riding up onto the gentle slope surface portion 52b, the slope surface portion 52d, the first medium slope surface portion 52f, or the second medium slope surface portion 52h is reduced, as shown in Figures 15(A) and 15(C).

[0133] This causes the driven cam 39 to move in the other axial direction, which is the direction in which the axial distance between the drive cam 38 and the driven cam 39 decreases, thereby reducing the force pressing the piston 36 of the elastic biasing mechanism 30 toward one axial side. Therefore, the piston 36, thrust bearing 61, and pressing member 62 are pressed toward the other axial side mainly by the elastic restoring force of the first friction plate 33 and the elastic member 37, and the first friction plate 33 or the second friction plate 34 closest to one axial side is pressed toward the other axial side by the piston 36. As a result, the first friction plate 33 and the second friction plate 34 are pressed against each other, the friction engagement portion 29 is engaged, and the electric friction clutch device 11 switches to the engagement mode.

[0134] In this example, when the electric friction clutch device 11 is maintained in the disengaged mode, it is necessary to continue to energize the shift motor 70 in order to prevent the piston 36 from moving toward the other axial side due to the elastic force of the elastic member 37. In contrast, when the electric friction clutch device 11 is maintained in the engaged mode, the elastic force of the elastic member 37 presses the piston 36 toward the other axial side, thereby pressing the first friction plate 33 and the second friction plate 34 against each other. Therefore, when the electric friction clutch device 11 is maintained in the engaged mode, it is not necessary to continue to energize the shift motor 70. In other words, the electric friction clutch device 11 of this example is configured as a normally closed type clutch device.

[0135] The rotation transmission state switching device 12 comprises a first member 74 having engagement recesses 77 at multiple 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 displaces axially in accordance with the rotation of the drive cam 38.

[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 of the first member 74 and the second member 75 is supported so as to be non-rotatable relative to the fixed portion 14, which 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 to be non-rotatable relative to the fixed portion 14, which does not rotate even during use. The mode select member 76 rotates in conjunction with the rotation of the drive cam 38.

[0137] The rotation transmission state switching device 12 has a free mode, which is switched based on the rotation or axial displacement of the mode select member 76, in which rotation of the first member 74 relative to the second member 75 is allowed regardless of the relative rotation direction between the first member 74 and the second member 75, and a locked mode in which relative rotation between the first member 74 and the second member 75 is prevented 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 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 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 locked mode, the rotation transmission state switching device 12 can have a one-way clutch mode in which only rotation of the first member 74 relative to the second member 75 in a predetermined direction is permitted. The rotation transmission state switching device 12 of this example has the one-way clutch mode. Specifically, the rotation transmission state switching device 12 can be switched among the free mode, the locked 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 can include a first engaging member that, when stretched across the first member 74 and the second member 75, allows rotation of one member relative to the other member in a predetermined direction and prevents rotation in the opposite direction to the predetermined direction, and a second engaging member that, when stretched across the first member 74 and the second member 75, prevents rotation of the one member relative to the other member in the opposite direction to the predetermined direction and allows rotation in the predetermined direction.

[0141] The rotation transmission state switching device 12 is 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 is switched to a locked mode by engaging the first engaging member and the second engaging member with both the first member 74 and the second member 75. Furthermore, the rotation transmission state switching device 12 is 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 multiple locations in the circumferential direction on its outer peripheral surface. That is, the first member 74 has a gear-shaped uneven portion 79 on its outer peripheral surface, in which engaging recesses 77 and protrusions 78 are alternately arranged in the circumferential direction.

[0143] The first member 74 also has an outer diameter side concave-convex engaging portion 80 on its inner circumferential surface, which is made up of concave and convex portions alternately arranged in the circumferential direction. The first member 74 is supported so as to be unable to rotate relative to the rotating member 10 by engaging the outer diameter side concave-convex engaging portion 80 with an inner diameter side concave-convex engaging portion 81 provided on the outer circumferential surface of the second cylindrical portion 24 of the rotating member 10. In other words, the first member 74 rotates integrally with the rotating member 10.

[0144] The second member 75 is supported around the first member 74 coaxially with the first member 74 and rotatable relative to the first member 74. That is, the inner circumferential surface of the second member 75 faces the outer circumferential surface of the first member 74, i.e., the tip surfaces of the convex portions 78, with a gap between them. The second member 75 has an inner diameter side concave-convex engaging portion 82 on its outer circumferential surface, where 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 concave-convex engaging portion 82 with an outer diameter side concave-convex engaging portion provided on the inner circumferential 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 comprises a base 83 having a rectangular cross-sectional shape and a cylindrical portion 84 that protrudes from the radially outer end of one axial side of the base 83 around its entire circumference toward one axial side.

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

[0147] Each first retaining recess 85 opens to the inner circumferential surface of the base 83 and to a side surface on the other axial side. Each first retaining recess 85 includes a spring retaining portion 87a and a pedestal portion 88a. When viewed from the other axial side, the spring retaining portion 87a has a generally rectangular opening shape with its major axis extending radially outward as it approaches one circumferential side (the front clockwise side in FIGS. 18 to 20 ). The pedestal portion 88a has a generally circular opening shape when viewed from the other axial side, and is disposed adjacent to the other circumferential side of the spring retaining portion 87a (the rear clockwise side in FIGS. 18 to 20 ).

[0148] Each second retaining recess 86 opens to the inner circumferential surface of the base portion 83 and to a side surface on the other axial side. When viewed from the other axial side, each second retaining recess 86 has a shape symmetrical to the first retaining recess 85 with respect to an imaginary plane including the center axis of the second member 75. That is, each second retaining recess 86 includes a spring retaining portion 87b and a pedestal portion 88b. When viewed from the other axial side, the spring retaining portion 87b has a substantially rectangular opening shape with its major axis extending radially outward as it approaches the other circumferential side. The pedestal portion 88b has a substantially circular opening shape when viewed from the other axial side, and is disposed adjacent to one circumferential side of the spring retaining portion 87a.

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

[0150] Each of the first claw members 89 includes a first base portion 93 and a first engagement claw 94 .

[0151] The first base portion 93 is configured in an approximately cylindrical shape and is supported (pivoted) on the pedestal portion 88 a 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 engagement claw 94 is configured in a generally flat plate shape and extends toward one circumferential side from the first base 93. The other axial side portion of the first engagement claw 94 faces (engages with) the outer circumferential surface of the annular protrusion 95 of the mode select member 76, and the one axial side portion faces (engages with) the uneven portion 79 of the first member 74 (engages with the engagement recess 77 so as to be able to be engaged and disengaged with).

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

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

[0155] The second engagement claw 97 is configured in a generally flat plate shape and extends toward the other circumferential side from the second base 96. The other axial side portion of the second engagement claw 97 faces the outer circumferential surface of the annular protrusion 95 of the mode select member 76, and the one axial side portion faces the uneven portion 79 of the first member 74.

[0156] The first claw biasing member 91 elastically biases the first engagement claw 94 of the first claw member 89 in a direction to engage with the engagement recess 77 of the first member 74. In other words, the first claw biasing member 91 applies a biasing force to the first claw member 89 in a direction to cause the first claw member 89 to swing clockwise in FIG. 19 around the central axis (pivot) of the first base 93. Specifically, the first claw biasing member 91 is formed of an elastic member such as a coil spring, and is held in an elastically compressed state between the bottom surface (surface facing radially inward) of the spring holding portion 87 a of the first holding recess 85 and the radially outer surface of the first engagement claw 94.

[0157] The second claw biasing member 92 elastically biases the second engagement claw 97 of the second claw member 90 in a direction to engage with the engagement 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 to cause the second claw member 90 to swing counterclockwise in FIG. 19 around the central axis of the second base 96. Specifically, the second claw biasing member 92 is formed of an elastic member such as a coil spring, and is held in an elastically compressed state between the bottom surface (surface facing radially inward) of the spring holding portion 87b of the second holding recess 86 and the radially outer surface of the second engagement claw 97.

[0158] As shown in Figure 17, the mode select member 76 has a base 98 that is approximately circular and has an annular protrusion 95 that protrudes from the radial middle of the side surface on the other axial side of the base 98 toward the other axial side around the entire circumference.

[0159] The base portion 98 has plate-side engagement holes 99 at a plurality of locations (three locations in the illustrated example) at equal circumferential intervals in a radially intermediate portion of its side surface on the other axial side. One axial end of the pin portion 54 fits (engages) into each plate-side engagement hole 99 without rattle. In other words, the mode select member 76 rotates integrally with the drive cam 38 (in the same direction and at the same speed).

[0160] The annular convex portion 95 has protrusions 100 that protrude radially outward at multiple locations on the outer circumferential surface. That is, the annular convex portion 95 has gear-shaped concave-convex portions 101 on the outer circumferential surface, in which the protrusions 100 and the concave portions are alternately arranged in the circumferential direction.

[0161] The first member 74, the second member 75, and the mode select member 76 are combined by a cover 102 and a retaining ring 103 so as to be capable of relative rotation but not capable of relative axial displacement (so as to prevent inadvertent separation in the axial direction), thereby forming the rotation transmission state switching device 12.

[0162] Specifically, with the first member 74 disposed radially inside one axial side portion of the base 83 of the second member 75, the annular lid body 102 is supported and fixed by screws to the side surface of one axial side of the second member 75, and the side surface of the other axial side of the radially inner portion of the lid body 102 faces the side surface of one axial side of the first member 74. This prevents the first member 74 from displacing axially to one side relative to the second member 75.

[0163] The annular protrusion 95 of the mode select member 76 is disposed radially inside the other axial side portion of the base 83 of the second member 75, with the tip surface (side surface on one axial side) of the annular protrusion 95 in sliding contact with or closely facing the side surface on the other axial side of the first member 74, and with the side surface on one axial side of the radially outer portion of the base 98 in sliding contact with or closely facing the side surface on the other axial side of the base 83 of the second member 75, a retaining ring 103 is engaged with the end on the other axial side of the inner circumferential surface of the cylindrical portion 84 of the second member 75. This prevents the first member 74 and the mode select member 76 from displacing toward the other axial side relative to the second member 75.

[0164] The rotation transmission state switching device 12 in this example is configured to be able to switch between free mode, locked mode, and one-way clutch mode by switching the engagement state between the first engagement claw 94 of the first claw member 89 and the engagement recess 77 of the first member 74, and the engagement state between the second engagement claw 97 of the second claw member 90 and the engagement 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 relative to the second member 75 is adjusted, and as shown in FIG. 20A , the protrusions 100 push the first engagement claws 94 radially outward against the elastic force of the first-claw biasing members 91, and push the second engagement claws 97 radially outward against the elastic force of the second-claw biasing members 92. This disengages the engagement recesses 77 of the first member 74 from the first engagement claws 94 and second engagement claws 97. In this state, rotation of the first member 74 relative to the second member 75 is permitted regardless of the relative rotation direction between the first member 74 and the second member 75. In other words, rotation of the first member 74 relative to the fixed portion 14 is permitted regardless of the rotation direction of the first member 74.

[0166] <Lock Mode> In the lock mode, the circumferential phase of the mode select member 76 relative to the second member 75 is adjusted, and as shown in FIG. 20(B) , the protrusion 100 is positioned circumferentially offset from the first engagement claw 94 of the first claw member 89 and the second engagement claw 97 of the second claw member 90. That is, the phases of the recesses of the uneven portion 101 and the first engagement claw 94 and the second engagement claw 97 are matched in the circumferential direction. This causes the engagement recesses 77 of the first member 74 to engage with the first engagement claw 94 and the second engagement claw 97. In this state, rotation of the first member 74 relative to the second member 75 is prevented regardless of the relative rotation direction between the first member 74 and the second member 75. That is, rotation of the first member 74 relative to the fixed portion 14 is prevented regardless of the rotation direction of the first member 74.

[0167] <One-way clutch mode> In the one-way clutch mode, the circumferential phase of the mode select member 76 relative to the second member 75 is adjusted, and as shown in Figure 20(C) , the protrusion 100 pushes only the second engagement pawl 97 radially outward against the elastic force of the second pawl biasing member 92. This causes the engagement recess 77 of the first member 74 to engage with the first engagement pawl 94, and disengages the engagement recess 77 from the second engagement pawl 97. In this state, rotation of the first member 74 relative to the second member 75 is permitted only in the predetermined direction (clockwise in Figure 20(C) ), and rotation in the direction opposite to the predetermined direction (counterclockwise in Figure 20(C) ) is prevented.

[0168] That is, when the first member 74 attempts to rotate in the predetermined direction relative to the second member 75, the convex portion 78 of the concave-convex portion 79 pushes the first engagement pawl 94 radially outward against the elastic force of the first pawl biasing member 91. As a result, rotation of the first member 74 in the predetermined direction is permitted. On the other hand, when the first member 74 attempts to rotate in the direction opposite to the predetermined direction relative to the second member 75, engagement between the engagement recess 77 and the first engagement pawl 94 prevents 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] The predetermined direction coincides with the normal rotation direction of the input member 8. The normal rotation direction of the input member 8 refers to the rotation direction of the input member 8 when moving the automobile 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, as an optional component, a planetary gear mechanism 13. 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 to switch the transmission path of torque transmitted through the planetary gear mechanism 13.

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

[0173] The ring gear 105 is disposed around the sun gear 104 and coaxially therewith.

[0174] The carrier 106 is supported coaxially with the sun gear 104 and the ring gear 105 and is capable of rotating relative 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 able to rotate (spin) around their own central axes.

[0176] Each of the plurality of planetary gears 107 can be configured 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 configured by a single-pinion planetary gear mechanism. Alternatively, the plurality of planetary gears 107 can have a first planetary gear that meshes with the sun gear 104 and a second planetary gear that meshes with the ring gear and the first planetary gear. That is, the planetary gear mechanism 13 can be configured by a double-pinion planetary gear mechanism.

[0177] In the two-speed transmission 3, 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 part 14 so that the reduction ratio between the input member 8 and the output member 9 can be switched between two levels, high and low, by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device.

[0178] Specifically, an input element, which is any one of sun gear 104, ring gear 105, and carrier 106, is connected to input member 8 so as to rotate integrally with input member 8. An output element, which is any one of sun gear 104, ring gear 105, and carrier 106 and is an element other than the input element, is connected to output member 9 so as to rotate integrally with output member 9. Furthermore, the remaining rotating elements, which are the sun gear 104, ring gear 105, and carrier 106 excluding the input element and the output element, are connected to rotating member 10 so as to rotate integrally with rotating member 10.

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

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

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

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

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

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

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

[0186] 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 (spin) around its own central axis. That is, in this example, the planetary gear mechanism 13 is configured as a single-pinion 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 configured 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 a ring gear 117 of the differential device that configures 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 wheels 108 by pressing friction members such as pads or shoes against a braking rotating body 110 such as a rotor or drum that 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, in order to realize the reduction ratio switching function and the cooperative control function, 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 amount of operation 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 wheels 108.

[0193] The control device 6 also includes a TCU (Transmission Control Unit) 114 that controls the two-speed transmission 3, and a VCU (Vehicle Control Unit) 116 that controls various components of the vehicle, including the TCU 114 and an inverter 115 for supplying power to the drive motor 2.

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

[0195] The reduction ratio switching function switches the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12 based on the rotational driving of the drive cam 38 by the electric actuator 32, thereby switching the two-speed transmission 3 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. In the electric vehicle drive system 1 of this example, the control device 6 executes the reduction ratio switching function by controlling the electric actuator 32 via the TCU 114 based on a command from the VCU 116, thereby 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, the electric friction clutch device 11 is switched to the connected mode, and the rotation transmission state switching device 12 is switched to the free mode.

[0197] Specifically, the electric actuator 32 rotates the drive cam 38, expanding the axial dimension of the cam device 31, thereby switching the electric friction clutch device 11 to the engagement 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] At the same time as switching the electric friction clutch device 11 to the connected mode, the rotation of the drive cam 38 adjusts the circumferential phase of the mode select member 76 relative to the second member 75, and switches the rotation transmission state switching device 12 to a free mode in which rotation of the first member 74 relative 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, rotation of the rotating member 10 relative to the fixed portion 14 is permitted, and rotation of the sun gear 104 is permitted.

[0199] In the low reduction ratio mode, the sun gear 104, ring gear 105, and carrier 106 rotate in the same direction and at the same speed, and the entire planetary gear mechanism 13 rotates as a unit, in a so-called glued state. Therefore, the rotational torque of the input member 8 is transmitted in this order from the input member 8 to the carrier 106 and then to the output member 9, as shown by the thick line in Figure 3(A) , and is extracted from the output member 9.

[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 electric actuator 32 rotates the drive cam 38, thereby reducing the axial dimension of the cam device 31, and 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 become rotatable relative to each other.

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

[0203] 3B, the rotational torque of the input member 8 is transmitted in the order of the input member 8, ring gear 105, rotational motion of the planetary gears 107, orbital motion of the planetary gears 107 based on meshing with the sun gear 104, carrier 106, and output member 9, and is then extracted from the output member 9. In the high reduction ratio mode, the reduction ratio between the input member 8 and the output member 9 is determined by the gear ratio of the ring gear 105 and the sun gear 104 (number of teeth of the ring gear 105 / number of teeth of the sun gear 104).

[0204] In the electric vehicle drive system 1 of this example, the reduction gear ratio between the input member 8 and the output member 9 can be switched between two levels, high and low, by switching the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12 based on the rotational driving of one drive cam 38 by one electric actuator 32. Specifically, for example, when the power input to the input member 8 is in a low-speed, high-torque range, the two-speed transmission 3 is switched to a high reduction ratio mode, and when the power is input to the input member 8 is in a high-speed, low-torque range, the two-speed transmission 3 is switched to a low reduction ratio mode. As a result, the acceleration performance and high-speed performance of an electric vehicle or hybrid vehicle running solely using the electric motor as a drive source can be made to have characteristics that are a continuation of the portion of the solid line a to the left of point P in Figure 36 and the portion of the chain line b to the right of point P, which are similar to those of a gasoline engine vehicle shown by the dashed line c in Figure 36.

[0205] The electric vehicle drive system 1 of this example does not require a hydraulic system for controlling friction engagement devices such as clutches and brakes, which simplifies the system in electric vehicles and hybrid vehicles, reducing costs and improving fuel economy.

[0206] In the electric vehicle drive system 1 disclosed herein, the two-speed transmission 3 can have a reduction ratio switching mode for smoothly switching from the high reduction ratio mode to the low reduction ratio mode during normal forward driving (powered driving). 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 rotation of the output member 9 is locked. In this example, the two-speed transmission 3 has the reduction ratio switching mode, neutral mode, and parking mode in addition to the low reduction ratio mode and the high reduction ratio mode.

[0207] <Reduction Ratio Switching Mode> When switching of the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode is initiated during normal forward traveling of the vehicle, first, based on adjusting the circumferential phase of the mode select member 76 relative to the second member 75, the protrusion 100 pushes only the second engagement pawl 97 radially outward against the elastic force of the second pawl biasing member 92, as shown in Figure 20(C) . As a result, only the first engagement pawl 94 engages with the engagement recess 77 of the first member 74, and the rotation transmission state switching device 12 switches to the one-way clutch mode which allows rotation of the first member 74 relative to the second member 75 only in the predetermined direction (the predetermined direction in Figure 20(C) ) and prevents rotation in the direction opposite to the predetermined direction.

[0208] Simultaneously with or after the rotation transmission state switching device 12 switches to the one-way clutch mode, the electric friction clutch device 11 starts switching from the disengagement mode to the engagement mode. During the switching of the electric friction clutch device 11 from the disengagement mode to the engagement mode, the rolling elements 40 move down the gently inclined surface portion 52b of the drive cam surface 52 based on the rotation of the drive cam 38, as shown in FIG. 15(B) and FIG. 15(A) in that order. As the amount of the rolling elements 40 climbing up from the first bottom portion 52a of the drive cam surface 52 gradually decreases, the force pressing the first friction plates 33 and the second friction plates 34 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 both axial side surfaces of the second friction plates 34 against (in sliding contact with) both axial side surfaces of the first friction plates 33.

[0209] As the fastening force F of the friction engagement portion 29 gradually increases during rotation of the input member 8 in the forward direction, 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, because the rotation transmission state switching device 12 is switched to the one-way clutch mode, the second member 75 does not rotate even if torque is applied to the second member 75 in the direction opposite to the predetermined direction. After the torque applied to the second member 75 in the direction opposite to the predetermined direction gradually decreases to zero, the direction of the torque applied to the second member 75 reverses (torque in the predetermined direction is applied to the second member 75), and at that moment, 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] To this end, by 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 a direction that widens the axial distance between the drive cam 38 and the driven cam 39 (to one axial side). This causes the piston 36 of the elastically biasing mechanism 30 to be pressed toward one axial side via the thrust bearing 61 and the pressing member 62, elastically compressing the elastic member 37 and eliminating the force pressing the first friction plates 33 and the second friction plates 34 against each other. Then, due to the action of the return spring 35, the distance between the first friction plates 33 and the second friction plates 34 widens, disengaging the friction engagement portion 29, and switching the electric friction clutch device 11 to the disengagement mode. As a result, the input member 8 and the rotating member 10 begin to rotate relative to each other, and the sun gear 104 and the ring gear 105 become rotatable relative to each other.

[0212] 20A , based on adjusting the circumferential phase of the mode select member 76 relative to the second member 75, the protrusion 100 pushes the first engagement pawl 94 radially outward and pushes the second engagement pawl 97 radially outward, as shown in FIG. 20A . This disengages the engagement recess 77 of the first member 74 from the first engagement pawl 94 and the second engagement pawl 97, and the rotation transmission state switching device 12 switches to the free mode in which rotation of the first member 74 relative 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, rotation of the rotating member 10 relative to the fixed portion 14 is permitted, and rotation of the sun gear 104 is permitted.

[0213] In such a neutral mode, the input member 8 and the output member 9 rotate freely relative to each other, and no torque is 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 reason, by rotating the driving cam 38 by the electric actuator 32, the rolling element 40 is positioned at the second bottom portion 52e of the driving cam surface 52, and the driven cam 39 is displaced in a direction that reduces the axial distance between the driving cam 38 and the driven cam 39 (toward the other axial side). This causes the force of the elastic biasing mechanism 30 that presses the piston 36 toward one axial side to be lost. Then, the piston 36, the thrust bearing 61, and the pressing member 62 are pressed toward the other axial side mainly by the elastic restoring force of the first friction plate 33 and the elastic member 37, and the first friction plate 33 or the second friction plate 34 that is closest to the one axial side to be pressed toward the other axial side by the piston 36.

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

[0217] 20(B) , the protrusion 100 is positioned at a position circumferentially offset from the first engagement pawl 94 and the second engagement pawl 97 based on adjusting the circumferential phase of the mode select member 76 relative to the second member 75. As a result, the engagement recess 77 of the first member 74 engages with the first engagement pawl 94 and the second engagement pawl 97, and the rotation transmission state switching device 12 switches to a lock mode in which rotation of the first member 74 relative to the second member 75 is prevented, regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, rotation of the rotating member 10 relative to the fixed portion 14 is prevented, and rotation of the sun gear 104 is prevented.

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

[0219] In the electric vehicle drive system 1 of this example, when switching from the high reduction ratio mode to the low reduction ratio mode during normal forward driving, the output torque and the rotational speed R of the drive motor 2 are controlled to prevent discontinuous (sudden) changes in the rotational torque of the output member 9 and to prevent the occurrence of gear change shock. ｓ The control is configured to control the rotation speed (amount of rotation) of shift motor 70. An example of this control will be described with reference to Figures 26 and 27. The following example is an example in which the rotational torque of output member 9 is maintained approximately constant before and after switching from the high reduction ratio mode to the low reduction ratio mode.

[0220] When switching from the high reduction ratio mode to the low reduction ratio mode is initiated based on conditions such as the vehicle running speed and accelerator opening, the electric actuator 32 first rotates the drive cam 38, thereby switching the rotation transmission state switching device 12 to the one-way clutch mode, and then adjusting the phase of the drive cam 38 in the rotation direction to the clutch touch point θｆ (S1) Clutch touch point θ ｆ is the point at which 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 at which the end of the piston 36 on the other axial side begins to come into contact with the first friction plate 33 or the second friction plate 34 located closest to one axial side, i.e., the clutch clearance C ｆ (see FIG. 25) is the point where the clutch touch point θ ｆ is calculated in advance using the clutch touch point detection function.

[0222] The phase of the drive cam 38 in the rotation direction is defined as the clutch touch point θ ｆ When the driving motor 2 is moved to the position indicated by arrow S1, the driving cam 38 transitions to the torque phase (S2). In the torque phase, the electric actuator 32 rotates the driving cam 38 at a predetermined rotational speed, thereby reducing the amount of the rolling elements 40 that climb up from the first bottom 52a, gradually increasing the pressing force between the first friction plates 33 and the second friction plates 34, i.e., the fastening force F of the friction engagement portion 29. At the same time, the output torque (driving torque, power torque) of the driving motor 2 is gradually increased.

[0223] That is, if the output torque of the drive motor 2 is maintained 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, resulting in a decrease in the rotational torque of the output member 9. Therefore, in the two-speed transmission 3 of this example, the output torque of the drive motor 2 is gradually increased in accordance with the increase in the fastening force F of the friction engagement portion 29, i.e., the amount of rotation of the drive cam 38, so that the rotational torque of the output member 9 can be maintained approximately constant regardless of the increase in the fastening force F of the friction engagement portion 29.

[0224] The relationship between the amount of rotation of the drive cam 38 and the increase in output torque of the drive motor 2 is determined in advance by experiment or calculation. In this example, the rotation speed of the drive cam 38 in S2 is set to be 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 set to be the same as the rotation speed of the drive cam 38 in S1, or can be set to be larger than the rotation speed of the drive cam 38 in S1.

[0225] More specifically, in S2, 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 amount of rotation of the drive cam 38. Then, in the next S3, it is determined whether the torque phase has ended.

[0226] That is, in the torque phase, as the fastening force F of the frictional engagement portion 29 increases, the clutch torque transmitted to the frictional 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 zero.

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

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

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

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

[0231] In the inertia phase, first, the output torque of the drive motor 2 is quickly reduced, and the rotation speed R of the motor output shaft 7 is reduced. ｓ The amount of reduction in the output torque of the drive motor 2 is proportional to the rotational speed R of the motor output shaft 7. ｓ There are no particular limitations on the amount of torque that can be reduced as long as it can promote a further decrease in torque. Specifically, for example, the output torque of the drive motor 2 can be reduced to 0 or a negative value.

[0232] Rotation speed R of motor output shaft 7 ｓ begins 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 should be output by the output member 9 when the two-stage transmission 3 has completed switching to the low reduction ratio mode (S4-2). In this example, because the rotational torque of the output member 9 is kept substantially constant before and after 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 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 phase is completed. ｉｎ and the rotation speed R of the output member 9 ｏｕｔ The output torque of the drive motor 2 can be controlled in accordance with the difference (differential rotation) ΔR between the rotation speed R of the motor output shaft 7 and the rotation speed R of the drive motor 2. ｓ As the rotation speed R of the input member 8 decreases, ｉｎAs the rotational speed difference ΔR decreases, the output torque of the drive motor 2 is increased, and when the rotational speed difference ΔR becomes 0, the rotational torque of the input member 8 can be controlled to become the target torque.

[0234] Next, in S4-3, the rotation speed R of the input member 8 is ｉｎ and the rotation speed R of the output member 9 ｏｕｔ Specifically, it is determined whether the rotation speed R of the input member 8 is equal to or not. ｉｎ and the rotation speed R of the output member 9 ｏｕｔ It is determined whether the difference (differential rotation) ΔR between the input member 8 and 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 attached to the input member 8 and the output member 9, respectively.

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

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

[0237] In S5, the electric actuator 32 rotates the driving cam 38 to a predetermined circumferential phase, positions the rolling element 40 at the first bottom 52a of the driving cam surface 52, and displaces the driven cam 39 toward the other axial side in a direction that reduces the axial distance between the driving cam 38 and the driven cam 39. As a result, the piston clearance C between the end of the pressing member 62 on one axial side and the side surface of the piston 36 on the other axial side is reduced. ｐ In other words, the piston clearance C ｐ is set to 0 or more, preferably greater than 0.

[0238] After the rolling element 40 has been moved to the first bottom 52a, the process proceeds to "End." As a result of the above, the two-speed transmission 3 is switched from the high reduction ratio mode to the low reduction ratio mode. Thereafter, the phase of the drive cam 38 in the circumferential direction is maintained, thereby maintaining the two-speed transmission 3 in the low reduction ratio mode.

[0239] As described above, in the electric vehicle drive system 1 of this example, by controlling the drive motor 2 and the shift motor 70, it is possible to prevent a (sudden) change in the rotational torque of the output member 9 and prevent the occurrence of a gear shift shock, even when switching between the high reduction ratio mode and the low reduction ratio mode during normal forward driving. However, in order to prevent the occurrence of a gear shift shock, it is necessary to control the output torque and the rotational speed R of the drive motor 2. ｓ In addition, the timing for controlling the number of rotations (amount of rotation) of the shift motor 70 becomes important.

[0240] For example, the phase of the drive cam 38 in the rotation direction is the same as the clutch touch point θ ｆ If the process proceeds to S2 and the output torque of the drive motor 2 is increased even though the torque has not yet reached this value, there is a possibility that the rotational torque of the output member 9 will increase inadvertently, as shown by the dashed line in Figure 27 (F).

[0241] Here, as the wear of the first friction plates 33 and the second friction plates 34 increases with use of the two-speed transmission 3, the amount of pressure required by the elastic biasing mechanism 30 to press the first friction plate 33 or the second friction plate 34, which is closest to one axial side, toward the other axial side in order to switch the electric friction clutch device 11 to the engagement mode increases. In other words, the amount of pressure required by the cam device 31 to press the piston 36 toward one axial side when switching the electric friction clutch device 11 to the disengagement mode 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 in the order shown in Figures 22(A) and 22(B). That is, as is clear from Figures 22(A) and 22(B), as the wear of the first friction plates 33 and the second friction plates 34 increases, the clutch touch point θ ｆ becomes smaller.

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

[0243] As is clear from FIGS. 22A and 22B, when the wear amount of the first friction plate 33 and the second friction plate 34 increases, the piston touch point θ ｐ The piston touch point θ ｐ is the point at which the elastic biasing mechanism 30 begins to be pressed in a direction to release the force pressing the first friction plate 33 and the second friction plate 34 against each other when the drive cam 38 is rotated in a direction to switch the friction engagement portion 29 from the connected state to the disconnected state. In other words, the piston touch point θ ｐ When 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 of the pressing member 62 on one axial side and the side surface of the piston 36 on the other axial side is ｐ (See FIG. 23) begins to occur.

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

[0245] 22(A) and 22(B), when the mode of the electric friction clutch device 11 is switched, the output torque T of the shift motor 70 and the current value A of the shift motor 70 change in the same manner. ｐ and clutch touch point θ ｆ is detected based on the current value A of the shift motor 70 when the electric friction clutch device 11 is switched from the engagement mode to the disengagement mode.

[0246] When the electric friction clutch device 11 is switched to the engagement 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 , a piston clearance C is formed between the end of the pressing member 62 on one axial side and the side surface of the piston 36 on the other axial side. ｐ This piston clearance C ｐ Based on the presence of the elastic member 37, displacement of the piston 36 toward the other axial side is permitted. Therefore, the piston 36 is elastically pressed toward the other axial side by the force of the elastic member 37 attempting to elastically restore its original shape, and the piston 36 presses the first friction plate 33 or the second friction plate 34 closest to one axial side toward the other axial side, causing the first friction plate 33 and the second friction plate 34 to press against each other.

[0247] To switch the electric friction clutch device 11 from the engagement mode to the disengagement mode, the drive cam 38 is rotated in the predetermined direction by energizing the shift motor 70, thereby increasing the amount of the rolling elements 40 that climb up from the first bottom portion 52a. At this time, the current value A of the shift motor 70 remains substantially constant (range α in FIGS. 22A and 22B) except for a temporary starting current.

[0248] When the pressing member 62 is moved toward one axial side by increasing the amount of the rolling element 40 climbing up from the first bottom portion 52a, the end of the pressing member 62 on one axial side comes into contact with the side surface of the piston 36 on the other axial side, as shown in FIG. ｐ becomes 0.

[0249] 24 , when the shift motor 70 further rotates the drive cam 38 in the predetermined direction, the driven cam 39 presses the piston 36 toward one axial direction via the pressing member 62 against the elastic restoring force of the elastic member 37. In this state, a portion of the elastic restoring force of the elastic member 37 is borne by the cam device 31 via the pressing member 62 and the thrust bearing 61, and the remainder is borne by the fixed part 14 via the friction engagement portion 29 and the rotation transmission state switching device 12. As the piston 36 is pressed toward one axial direction, the force pressing the first friction plate 33 and the second friction plate 34 toward one another gradually decreases, mainly due to the elastic restoring force of the second friction plate 34 and the elastic member 37. In other words, the fastening force F of the friction engagement portion 29 gradually decreases.

[0250] While the fastening force F of the friction engagement portion 29 is gradually reduced, the current value A of the shift motor 70 increases at a substantially constant rate (slope) (range β in FIGS. 22A and 22B). 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, the control device 6, using the piston touch point detection function, starts energizing the shift motor 70 in order to switch the electric friction clutch device 11 from the engagement mode to the disengagement mode, and then calculates a phase (rotation angle from a reference position (e.g., an initial position where the rolling element 40 is located at the bottom of the recess)) θ in the rotation direction of the drive cam 38 when the current value A of the shift motor 70 starts to increase at an increasing rate equal to or greater than a predetermined first threshold value, as a function of the piston clearance C. ｐ Piston touch point θ where ｐ The first threshold value can be determined in advance by experiment, simulation, or the like.

[0252] The rate of increase in the current value A is the increase ΔA in 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 ΔA in the current value A per unit time can also be used for the determination.

[0253] The fastening force F of the friction engagement portion 29 gradually decreases, and from that moment on, as shown in FIG. 25, a clutch clearance C is generated between the end of the piston 36 on the other axial side and the first friction plate 33 or the second friction plate 34 located closest to one axial side. ｆ Clutch clearance C ｆ When the clutch clearance C 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. ｆ After this begins to occur, current value A of shift motor 70 increases slowly and logarithmically (range γ in FIGS. 22A and 22B). That is, the rate of increase of current value A in range γ is smaller than the rate of increase of current value A in range β.

[0254] The control device 6 detects by its clutch touch point detection function whether the phase of the drive cam 38 in the rotation direction reaches the piston touch point θ when the electric friction clutch device 11 is switched from the connection mode to the disconnection mode. ｐ The phase θ in the rotation direction of the drive cam 38 when the rate of increase of the current value A of the shift motor 70 becomes equal to or less than the second threshold value after exceeding the second threshold value is defined as the clutch clearance C. ｆ Clutch touch point θ becomes 0 ｆ The second threshold is smaller than the first threshold, and the second threshold can be determined in advance by experiment, simulation, or the like.

[0255] In addition, the piston touch point θ ｐ and clutch touch point θ ｆ The detection of the piston touch point θ can be performed at any timing as long as it does not interfere with the running of the automobile equipped with the two-speed transmission 3. Specifically, it can be performed, for example, immediately after the ignition key is turned on, or when the two-speed transmission is switched from the low reduction ratio mode to the high reduction ratio mode, such as during kickdown acceleration or engine braking. However, if the above operation is attempted while the vehicle is running, there is a problem that the drive cam 38 cannot be driven at a desired rotational speed. For this reason, the piston touch point θｐ and clutch touch point θ ｆ It is preferable to perform the detection while the vehicle is stopped, such as immediately after the ignition key is turned on.

[0256] In the electric vehicle drive system 1 of this example, when switching between the high reduction ratio mode and the low reduction ratio mode, the control device 6 calculates the rotation amount of the drive cam 38, which is rotationally driven by the shift motor 70 via the reducer 71, based on the piston touch point θ detected by the piston touch point detection function. ｐ and / or the clutch touch point θ detected by the clutch touch point detection function ｆ Specifically, for example, when 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, in S1, the clutch touch point θ detected by the clutch touch point detection function is used as the target value of the phase in the rotational direction of the drive cam 38. ｆ Use.

[0257] In this way, in the electric vehicle driving device 1 of this example, the piston touch point θ ｐ and clutch touch point θ ｆ Even if the initial position is changed, the corrected piston touch point θ ｐ and clutch touch point θ ｆ Therefore, the electric vehicle driving device 1 of this embodiment can prevent the occurrence of gear shift shock regardless of the wear of the first friction plates 33 and the second friction plates 34.

[0258] In the electric vehicle drive system 1 of this example, the reduction ratio change mode is passed through during the change from the high reduction ratio mode to the low reduction ratio mode during normal forward traveling, so that torque loss can be reduced while suppressing the gear shift shock that accompanies the mode change. The reason for this will be explained with reference to Figures 30 and 31.

[0259] 30 shows a portion 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 whether or not relative rotation is permitted between input member 8 and rotating member 10, in other words, whether or not relative rotation is permitted between ring gear 105 and sun gear 104, and a second friction engagement device 202 that switches whether or not rotation of rotating member 10 is permitted relative to fixed part 14, in other words, whether or not rotation of sun gear 104 is permitted. That is, the two-speed transmission of the comparative example employs a second friction engagement device 202 that switches modes by pressing first friction plates 33 and second friction plates 34 against or away from each other, instead of the rotation transmission state switching device 12 of the two-speed transmission of the present example.

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

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

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

[0263] In contrast, in this example, in order to switch from the high reduction ratio mode to the low reduction ratio mode based on the rotation of the drive cam 38, the rotation transmission state switching device 12 is set to the one-way clutch mode before the electric friction clutch device 11 starts to switch from the disengagement mode to the engagement mode. Therefore, 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 sun gear 104 is allowed to rotate in the predetermined direction at the moment the direction of the torque applied to the sun gear 104 is reversed. Therefore, it is possible to suppress torque loss in the two-speed transmission 3 while suppressing the shift shock associated with the mode switch.

[0264] 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 portions 29 is small enough to prevent torque loss at the contact portions between both axial side surfaces of the first friction plates 33 and both axial side surfaces of the second friction plates 34. On the other hand, when the fastening force F of the friction engagement portions 29 is increased to a magnitude large enough to transmit torque without causing slippage at the contact portions between both axial side surfaces of the first friction plates 33 and both axial side surfaces of the second friction plates 34, the reduction ratio is the same as the reduction ratio in the low reduction ratio mode, i.e., 1.

[0265] When the fastening force F of the friction engagement portion 29 is such that slippage occurs at the contact points between both axial side surfaces of the first friction plate 33 and both axial side surfaces of the second friction plate 34, the reduction ratio between the input member 8 and the output member 9 becomes a value that corresponds to the magnitude of the input torque, the rotational speed, etc.

[0266] When the input member 8 is rotating in the forward direction and the mode is being switched 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 the direction opposite to the predetermined direction. Here, in the rotation transmission state switching device 12, rotation of the second member 75 in the direction opposite to the predetermined direction is prevented even during switching from the lock mode to the one-way clutch mode. In other words, the reduction ratio between the input member 8 and the output member 9 during 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 direction and during switching from the reduction ratio switching mode to the low reduction ratio mode, torque is applied in the predetermined direction to the second member 75 of the rotation transmission state switching device 12. Here, in the rotation transmission state switching device 12, rotation of the second member 75 in the predetermined direction is permitted even during switching from the one-way clutch mode to the free mode.

[0268] Note that when the input member 8 rotates in the reverse direction, i.e., when a vehicle equipped with the electric vehicle drive system 1 of this embodiment is reversing, the vehicle rarely travels at high speed. Therefore, when the input member 8 is rotating in the reverse direction, there is little need to switch to the reduction ratio switching mode, which allows the sun gear 104 to rotate, at the moment the direction of torque applied to the sun gear 104 is reversed by switching the electric friction clutch device 11 to the one-way clutch mode, as occurs when the input member 8 is rotating in the forward direction. Furthermore, even when the input member 8 rotates in the forward direction, the vehicle is primarily in a deceleration state when switching from the low reduction ratio mode to the high reduction ratio mode. In this case, power is not transmitted from the input member 8 to the output member 9, so there is little need to switch the two-speed transmission 3 to the reduction ratio switching mode.

[0269] Next, a description will be given of the cooperative control function of the control device 6. When torque is passing through the two-speed transmission 3 from the output member 9 side to the input member 8 side, torque is applied to the first member 74 that tends to rotate the first member 74 in one circumferential direction relative to the second member 75, and the rotation of the first member 74 in one circumferential direction relative to the second member 75 is prevented by the rotation transmission state switching device 12, the cooperative control function executes a pre-shift process in which the regenerative torque of the drive motor 2 is reduced and the braking force of the friction brake device 5 is increased in response to a mode switch of the two-speed transmission 3 by the reduction ratio switching function, before the second engagement pawl 97 is pressed radially by the protrusion 100 to retract from the engagement recess 77.

[0270] In other words, when torque is being transmitted through the two-speed transmission 3 from the output member 9 side to the input member 8 side, i.e., when the vehicle is in regenerative driving mode, if the two-speed transmission 3 is to be switched from the high reduction ratio mode to the low reduction ratio mode, the electric friction clutch device 11 must be switched from the disconnection mode to the connection mode, and the rotation transmission state switching device 12 must be switched from the lock mode to the one-way clutch mode, and then to the free mode.

[0271] Here, when a vehicle equipped with the electric vehicle drive device 1 is traveling forward regeneratively 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 one circumferential direction relative to the second member 75. As a result, the side surface of the inner surface of the engagement recess 77 provided in the first member 74 that faces one circumferential direction is pressed against the tip surface of the second engagement pawl 97. Therefore, during switching of the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode, there is a possibility that an excessively large force will be required to press the second engagement pawl 97 radially outward by the protrusion 100 of the mode select member 76 in order to disengage the engagement recess 77 from the second engagement pawl 97 in order to switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode.

[0272] Therefore, in the electric vehicle drive system 1 of this example, when the two-stage transmission 3 is being switched from the high reduction ratio mode to the low reduction ratio mode while the vehicle is running in a regenerative mode, when the rotation transmission state switching device 12 is being switched from the lock mode to the one-way clutch mode, the regenerative torque T ２ By controlling the braking force BF of the friction brake device 5 in coordination with the force required for mode switching of the rotation transmission state switching device 12, it is possible to prevent the force required for mode switching of the rotation transmission state switching device 12 from becoming excessive, while suppressing or preventing the occupants from feeling uncomfortable.

[0273] In the electric vehicle drive system 1 of this example, the VCU 116 controls the rotation 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 of the friction brake device 5, thereby performing a cooperative control function.

[0274] 28 and 29 will be used to explain a method for switching the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode while executing coordinated control that coordinates the rotation speed and torque of the drive motor 2, the mode of the electric friction clutch device 11 and the mode of the rotation transmission state switching device 12, and the braking force of the friction brake device 5, in a state where torque is transmitted through the two-speed transmission 3 from the output member 9 side to the input member 8 side. The following example is an example where the rotation speed of the output member 9 is maintained approximately constant before and after switching from the high reduction ratio mode to the low reduction ratio mode.

[0275] When torque is being transmitted through the two-speed transmission 3 from the output member 9 side to the input member 8 side, i.e., when the vehicle is running in a regenerative mode, the reduction ratio switching function starts switching from the high reduction ratio mode to the low reduction ratio mode based on conditions such as the vehicle running speed, and first, as a pre-shift process, the control device 6 controls the drive motor 2 and the friction brake device 5 in cooperation with each other. Specifically, by controlling the supply of electricity to the drive motor 2, the regenerative torque T ２While decreasing (P1-1), the braking force BF by the friction brake device 5 is increased (P1-2). ２ When the torque T ９ also decreases.

[0276] More specifically, in this example, the regenerative torque T ２ until it reaches 0, the braking force BF of the friction brake device 5 is increased by the rotational speed R of the output member 9. ｏｕｔ is increased so that it remains approximately constant.

[0277] In this example, the regenerative torque T ２ However, when the electric vehicle drive device of the present disclosure is implemented, as long as the force required to switch the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode in the next first mode switching step (P2), that is, the force required to rotationally drive the mode select member 76 in order to push only the second engagement pawls 97 radially outward against the elastic force of the second pawl biasing member 92 by the protrusion 100, can be reduced, the regenerative torque T ２ can also be greater than 0.

[0278] In FIG. ２ A negative value of T means that it is a regenerative torque. ２ Increasing the negative value of T ２ This means bringing the value closer to 0 (reducing the absolute value of a negative value).

[0279] 29, in order to facilitate understanding of the invention, the braking force BF of the friction brake device 5 is expressed as a negative value, and increasing the braking force BF means increasing the braking force BF in the negative direction (increasing the absolute value of the negative value). ９ A negative value of π / (π / π) means that the torque passes through the output member 9 in a direction from the drive wheel 108 side to the drive motor 2 side.

[0280] Regenerative torque T by the drive motor 2 ２ During the pre-shift process, the braking force BF of the friction brake device 5 is increased while the regenerative torque T ２ The drive wheels 108 are decelerated by a combined braking force of the regenerative braking force T (regenerative braking force) and the friction braking force BF by the friction brake device 5. ２ After the friction braking force BF of the friction brake device 5 becomes 0, the driving wheels 108 are decelerated.

[0281] In the next first mode switching process (P2), the drive cam 38 is rotationally driven by the electric actuator 32, which in turn rotates the mode select member 76, thereby switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode.

[0282] 20(B) and 20(C) in that order, the circumferential phase of the mode select member 76 relative to the second member 75 is adjusted, and the protrusion 100 pushes up only the second engagement pawl 97 radially outward against the elastic force of the second pawl biasing member 92, causing it to retract from the engagement recess 77. This switches the rotation transmission state switching device 12 to a one-way clutch mode in which rotation of the first member 74 relative to the second member 75 is permitted only in the predetermined direction (clockwise in FIG. 20(C)) and rotation in the direction opposite to the predetermined direction is prevented.

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

[0284] In the inertia stroke, first, the regenerative torque T ２ By increasing the rotation speed R of the motor output shaft 7, ｓ Promotes a reduction in (P3).

[0285] Regenerative torque T by the drive motor 2 ２ The speed and amount of increase of the motor output shaft 7 R ｓHowever, in order to quickly switch the mode of the two-speed transmission 3, the rotation speed R of the motor output shaft 7 is preferably reduced. ｓ In order to quickly decrease the load, it is preferable to increase the load as quickly as possible within a range that does not place an excessively large load on the drive motor 2.

[0286] Rotation speed R of motor output shaft 7 ｓ When the regenerative torque T ２ Specifically, the rotation speed R of the motor output shaft 7 is decreased (P4). ｓ When the regenerative torque T ２ The regenerative torque T ２ More specifically, in this example, the rotation speed R of the motor output shaft 7 is reduced. ｓ is the rotation speed R of the output member 9 before the mode change of the two-speed transmission 3 starts. ｏｕｔ When the regenerative torque T ２ The regenerative torque T ２ Reduces.

[0287] In the next inertia phase end determination step (P5), it is determined whether the inertia phase has ended. Specifically, the rotation speed R of the motor output shaft 7 detected by the input rotation sensor 112 is ｓ More specifically, in this example, the rotation speed R of the motor output shaft 7 is determined. ｓ is the rotation speed R of the output member 9 before the mode change of the two-speed transmission 3 starts. ｏｕｔ It is determined whether

[0288] Rotation speed R of motor output shaft 7 ｓ If it is determined that the torque phase end determination step (P5) has not reached the target value, the torque phase end determination step (P6) is executed again after a predetermined time has elapsed.

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

[0290] In the shift completion process, 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 increased until the torque that can be transmitted without the first friction plates 33 and the second friction plates 34 slipping on each other is equal to or greater than the torque that passes through the friction engagement portion 29 after the two-speed transmission 3 has completely switched to the low reduction ratio mode, preferably greater than the torque that passes through the friction engagement portion 29 after the two-speed transmission 3 has completely switched to the low reduction ratio mode.

[0291] Next, while reducing the braking force BF by the friction brake device 5 (P7-1), the regenerative torque T ２ Specifically, when the braking force BF of the friction brake device 5 becomes 0, the rotational torque T of the output member 9 is increased. ９ The magnitude of the rotational torque T of the output member 9 at the time when the mode switching of the two-speed transmission 3 is started is ９ The regenerative torque T ２ Increase.

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

[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 free mode, thereby completing the switching of the two-speed transmission 3 to the low reduction ratio mode (P8), and then the process ends.

[0294] In the electric vehicle drive system 1 of this example, during regenerative running of the vehicle, in order to switch the two-stage transmission 3 from the high reduction ratio mode to the low reduction ratio mode, before switching the rotation transmission state switching device 12 from the lock mode to the one-way clutch mode, the regenerative torque T ２ Therefore, the force that presses the side surface of the inner surface of the engagement recess 77 provided in the first member 74 that faces one circumferential direction against the tip end surface of the second engagement claw 97 can be reduced.

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

[0296] In this example, the force pressing the side surface of the inner surface of the engagement recess 77 facing one circumferential direction against the tip surface of the second engagement pawl 97 can be reduced or eliminated, so that the force required to press the second engagement pawl 97 radially outward by the protrusion 100 of the mode select member 76 to disengage the engagement recess 77 from the second engagement pawl 97 in order to switch the rotation transmission state switching device 12 from the locked mode to the one-way clutch mode can be reduced. 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 regenerative driving of the vehicle, the mode switching of the rotation transmission state switching device 12 can be performed smoothly.

[0297] In the electric vehicle drive system 1 of this example, during regenerative running of the vehicle, while the two-stage transmission 3 is being switched from the high reduction ratio mode to the low reduction ratio mode, and before the rotation transmission state switching device 12 is switched from the lock mode to the one-way clutch mode, the regenerative torque T ２ In cooperation with the reduction of the regenerative torque T ２Even when the vehicle speed is reduced, it is possible to suppress or prevent the driver and other passengers from feeling as if the deceleration acceleration (deceleration G) has been lost, thereby suppressing or preventing the driver and other passengers from feeling uncomfortable.

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

[0299] Furthermore, the electric vehicle drive system 1 of this embodiment can ensure good torque transmission efficiency, the reason for which will be explained next.

[0300] When the cam device 31 generates a pressing force, that is, when 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. 3B ), a force directed toward one axial side is applied to the thrust bearing 61. In addition, a reaction force caused by the driven cam 39 pressing the piston 36 toward one axial side is applied to the radial bearing 42 toward the other axial side via the rolling element 40 and the driving cam 38.

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

[0302] In this example, when the cam device 31 generates a pressing force, i.e., when the piston 36 is pressed toward one axial side, the axial dimension of the elastic member 37 elastically contracts, the force pressing 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 in which the electric friction clutch device 11 is disengaged and the rotation transmission state switching device 12 has switched to the lock mode, relative rotation of the rotating member 10 with respect to the fixed part 14 is prevented. In this state, the bearing ring 63 a on one axial side and the bearing ring 63 b 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 other words, when an axial force (left and right direction in FIG. 2B) is applied to the thrust bearing 61 and the radial bearing 42 and rolling resistance increases, the race 63a on one axial side and the race 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. This makes it possible to prevent torque loss in the thrust bearing 61 and the radial bearing 42.

[0304] The pressing force generated by the cam device 31 is applied from the driven cam 39 to the rotating member 10 in one axial direction via the pressing member 62, thrust bearing 61, piston 36, and elastic member 37. In contrast, the reaction force caused by the pressing force generated by the cam device 31 is applied from the driving cam 38 to the rotating member 10 in the other axial direction via the radial bearing 42. In this way, the axial forces caused by the pressing forces generated 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 is switched to the free mode and relative rotation of the rotating member 10 with respect to the fixed part 14 is permitted (the state shown in FIG. 3A), the electric friction clutch device 11 is engaged and the cam device 31 does not generate a pressing force. In this state, no axial force (the left-right direction in FIG. 3A) associated with the pressing force generated by the cam device 31 is applied to the thrust bearing 61 and the radial bearing 42, so the rolling resistance of the thrust bearing 61 and the radial bearing 42 does not increase unnecessarily and torque loss does not become excessively large.

[0306] In short, in the electric vehicle drive system 1 of this example, except for a short period during mode switching, the thrust bearing 61 and radial bearing 42 do not rotate when the axial force caused by the pressing force generated by the cam device 31 is applied and the rolling resistance is increased. Therefore, it is possible to prevent excessive torque loss from occurring in the thrust bearing 61 and 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 that does not have a one-way clutch mode, i.e., that includes a rotation transmission state switching device that has only a free mode and a locked mode. In such a modified example, when switching from the high reduction ratio mode to the low reduction ratio mode, as shown in Figure 32, the rotation transmission state switching device is switched from the locked mode to the free mode, and then the electric friction clutch device is switched from the disengaged mode to the engaged mode.

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

[0309] That is, when balls are used as the rolling elements that make up the cam device, slippage may occur at the rolling contact area between the surface of the rolling element and the drive cam surface when the drive cam is rotated. If slippage occurs at the rolling contact area between the surface of the rolling element and the drive cam surface, the driven cam may not be able to displace in the axial direction, or the amount of axial displacement of the driven cam relative to the amount of rotation of the drive cam may not be sufficiently ensured.

[0310] In contrast, in the two-speed transmission 3 of this example, rollers are used as the rolling elements 40, and the rolling elements 40 are supported to rotate (spin) freely relative to the driven cam 39 about a rotation axis C that faces in a radial direction from the central axis of the driven cam 39. Therefore, when the drive cam 38 is rotated, slippage can be prevented at the rolling contact portion between the outer circumferential surface of the rolling element 40 and the drive cam surface 52, and the driven cam 39 can be reliably displaced in the axial direction based on the rotation of the drive cam 38. As a result, the mode switching of the two-speed transmission 3 can be performed with high precision. However, as mentioned 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 Figures 33 to 35. In an electric vehicle driving device 1a of this example, a two-speed transmission 3a has a different structure from 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 an engagement mode in which torque is transmitted between the rotating member 10a and the input member 8a and a disengagement mode in which torque is not transmitted between the rotating member 10a and the input member 8a. That is, in this example, the second clutch member rotates integrally with the input member 8a. More specifically, the second clutch member is formed by the input member 8a itself. Furthermore, the first clutch member is formed by the rotating member 10a itself.

[0314] In addition, in this example, the electric friction clutch device 11a is provided with an elastic biasing mechanism 30a that is arranged between the friction engagement portion 29 and the driven cam 39 of the cam device 31 and elastically biases the friction engagement portion 29 and the driven cam 39 in directions away from each other.

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

[0316] The elastic member 37a is made up of a single disc spring.

[0317] The thrust bearing 61a has a pair of raceways 63c, 63d and a plurality of rolling elements 64 arranged to roll freely between the pair of raceways 63c, 63d.

[0318] In this example, when the electric friction clutch device 11a is switched to a disconnection mode in which torque is not transmitted between the rotating member 10a and the input member 8a, the electric actuator 32 rotates the drive cam 38, thereby moving the driven cam 39 in a direction that reduces the axial distance between the drive cam 38. This causes the force pressing the first friction plate 33 and the second friction plate 34 against each other to be lost. As a result, the return spring 35 acts to widen the distance between the first friction plate 33 and the second friction plate 34, disengaging the friction engagement portion 29 and switching the electric friction clutch device 11 to the disconnection mode.

[0319] On the other hand, when the electric friction clutch device 11a is switched to a connection mode in which torque is transmitted between the rotating member 10a and the input member 8a, the electric actuator 32 rotates the drive cam 38, thereby moving the driven cam 39 in a direction that increases the axial distance between the drive cam 38 and the driven cam 39. As a result, the driven cam 39 presses the first friction plates 33 and the second friction plates 34 against each other via the elastic member 37a and the thrust bearing 61a. As a result, the first friction plates 33 and the second friction plates 34 press against each other, and the friction engagement portion 29 is engaged, thereby switching the electric friction clutch device 11a to the connection mode.

[0320] In this example, when the electric friction clutch device 11a is to be maintained in the engaged mode, it is necessary to continue to energize the shift motor 70. In contrast, when the electric friction clutch device 11a is to be maintained in the disengaged mode, it is not necessary to continue to energize the shift motor 70. In other words, the electric friction clutch device 11 in this example is configured as a normally open type clutch device.

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

[0322] In the electric vehicle drive device 1a of this example, the control device 6 also has a reduction ratio switching function that switches 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 low reduction ratio mode, the electric friction clutch device 11a is switched to the connected mode. This causes the input member 8a and the rotating member 10a to rotate integrally, and the sun gear 104a and the ring gear 105a to rotate integrally. In addition, the rotation transmission state switching device 12a is switched to the free mode. This allows the rotating member 10a to rotate relative to the fixed part 14, and also allows the ring gear 105a to rotate.

[0324] In the low reduction ratio mode, the sun gear 104a, ring gear 105a, and carrier 106a rotate in the same direction and at the same speed, and the entire planetary gear mechanism 13a rotates as a unit, in a so-called glued state. Therefore, the rotational torque of the input member 8a is transmitted in this order to the input member 8a, carrier 106a, and output member 9a, and is taken out from the output member 9, as shown by the thick line in Figure 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 disengagement mode. This allows the input member 8a and the rotating member 10a to rotate relative to each other, and also allows the sun gear 104a and the ring gear 105a to rotate relative to each other. In addition, the rotation transmission state switching device 12a is switched to the lock mode. This prevents the rotating member 10a from rotating relative to the fixed part 14, and prevents the ring gear 105a from rotating.

[0326] In the high reduction ratio mode, the rotational torque of the input member 8a is transmitted in the following order: input member 8a, sun gear 104a, rotational motion of planetary gear 107a, orbital motion of planetary gear 107a based on meshing with ring gear 105a, carrier 106a, and output member 9a, as shown in Figure 34 (B), and is then extracted from output member 9a.

[0327] In this example, the two-speed transmission 3a can also be switched among a reduction ratio change mode, a neutral mode, and a parking mode.

[0328] The control device 6 has a cooperative control function that, when torque is passing through the two-speed transmission 3a from the output member 9a side to the input member 8a side, torque is applied to the first member 74 that tends to rotate the first member 74 in one circumferential direction relative to the second member 75, and the rotation of the first member 74 in one circumferential direction relative to the second member 75 is prevented by the rotation transmission state switching device 12a, in response to a mode switch of the two-speed transmission 3a by the reduction ratio switching function, executes a pre-shift process that reduces the regenerative torque of the drive motor 2 and increases the braking force of the friction brake device 5 before the second engagement pawl 97 is pressed radially by the protrusion 100 to retract from the engagement recess 77. This enables smooth mode switching of the rotation transmission state switching device 12a even during regenerative running in which regenerative torque acts on the drive motor 2.

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

[0330] REFERENCE SIGNS LIST 1, 1a Electric vehicle drive device 2 Drive motor 3, 3a Two-speed transmission 4 Torque transmission mechanism 5 Friction brake 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 portion 15 Drive gear 16 Input gear 17 Output gear 18 Small diameter flange portion 19 Flange portion 20 Through hole 21 First circular ring portion 22 First cylindrical portion 23 Second circular ring portion 24 Second cylindrical portion 25 Shaft member 26 Stepped cylindrical member 27 Small diameter cylindrical portion 28 Female spline portion 29 Friction engagement portion 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 Drive cam 39 Driven cam 40 Rolling element 41 Cylindrical member 42 Radial bearing 43 Angular contact ball bearing 44 Cylindrical portion 45 Outward flange portion 46 Inner ring 47 Outer ring 48 Rolling element 49 Inner ring 50 Outer ring 51 Ball 52 Drive cam surface 52a First bottom portion 52b Gently inclined surface portion 52c First flat surface portion 52d Inclined surface portion 52e Second bottom portion 52f First intermediate inclined surface portion 52g Second flat surface portion 52h Second intermediate inclined surface portion 53 Wheel tooth 54 Pin portion 55 Female spline portion 56 Male spline portion 57 Rectangular hole 58a, 58b Support plate portion 59 Support hole 60 Support recess 61, 61a Thrust bearing 62 Pressing member 63a, 63b, 63c, 63d Raceway ring 64 Rolling element 65 Preload applying means 66 Base portion 67 Partial cylindrical portion 68 Support shaft 69 Roller 70 Shift motor 71 Reducer 72 Worm 73a, 73b Support bearing 74 First member 75 Second member 76 Mode select member 77 Engaging recess 78 Convex portion 79 Concave-convex portion 80 Outer diameter side concave-convex engaging portion 81 Inner diameter side concave-convex engaging portion 82 Inner diameter side concave-convex engaging portion 83 Base portion 84 Cylindrical portion85 First retaining recess 86 Second retaining recess 87a, 87b Spring retaining portion 88a, 88b Base portion 89 First claw member 90 Second claw member 91 First claw biasing member 92 Second claw biasing member 93 First base portion 94 First engaging claw 95 Annular convex portion 96 Second base portion 97 Second engaging claw 98 Base portion 99 Plate side engaging hole 100 Projecting portion 101 Concave and concave portion 102 Cover body 103 Retaining ring 104, 104a Sun gear 105, 105a Ring gear 106, 106a Carrier 107 Planetary gear 108 Drive wheel 109 Drive shaft 110 Braking rotor 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 two-speed transmission having a drive motor having a motor output shaft, an input member capable of transmitting torque between 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 for transmitting torque between the output member and a driving wheel, a friction brake device disposed between the output member and the driving wheel and for braking the rotation of the driving wheel, and a control device, wherein the electric friction clutch device comprises: a first clutch member which rotates integrally with the rotating member or which is constituted by the rotating member itself; a second clutch member which is supported coaxially with the first clutch member so as to be rotatable relative to the first clutch member, and which rotates integrally with the input member or the output member or which 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 be capable of relative displacement in the axial direction; a cam device having a drive cam and a driven cam supported to be capable of relative rotation with respect to the drive cam and relative displacement in the axial direction, the cam device expanding and contracting an axial interval 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 rotating and driving the drive cam by the shift motor via the reducer; and A first member having a plurality of engagement recesses at circumferential positions; a second member arranged coaxially with the first member;a mode select member having protruding portions protruding in a radial or axial direction at a plurality of circumferential locations, and rotating or displacing in the axial direction with rotation of the drive cam; a first claw member having a first base portion pivotally supported on the second member and a first engaging claw extending from the first base portion toward a first side in the circumferential direction; a second claw member having a second base portion pivotally supported on the second member and a second engaging 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 engaging claw in a direction to engage with the engaging recess; and a second claw biasing member that elastically biases the second engaging claw in a direction to engage with the engaging 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 to be non-rotatable relative to a fixed portion 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 to prevent 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 to retract the first engagement claw and the second engagement claw from the engagement recess and engages the other engagement claw with the engagement recess, thereby allowing only rotation of the one member in a predetermined direction relative to the other member and preventing rotation of the one member in a direction opposite to the predetermined direction relative to the other member, and a free mode in which the first engagement claw and the second engagement claw are pressed in the radial direction or the axial direction by the protrusion to retract the first engagement claw and the second engagement claw from the engagement recess, The control device includes: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 of increasing the braking force by the friction brake device while reducing the regenerative torque of the drive motor, before one of the first engagement claws and the second engagement claws, which extends from a base pivotally supported on the second member toward the other circumferential side, is pressed radially or axially by the protrusion to retract from the engagement recess, in a state in which torque passes through the two-speed transmission from the output member side toward the input member side, a torque is applied to the one member tending to rotate the one member toward one circumferential side relative to the other member, and the rotation transmission state switching device prevents the one member from rotating toward one circumferential side relative to the other member.

2. The electric vehicle drive device according to claim 1, wherein in the pre-shift process, the regenerative torque of the drive motor is reduced to zero.

3. A drive device for an electric vehicle as described in claim 1 or 2, wherein the two-speed transmission is configured to be switchable to the locked mode, and 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 disconnected mode and the rotation transmission state switching device to the locked mode, and switches the two-speed transmission to the low reduction ratio mode by switching the electric friction clutch device to the connected mode and the rotation transmission state switching device to the free mode.

4. A drive device for an electric vehicle as described in claim 3, wherein the two-speed transmission is configured to be able to switch to the one-way clutch mode, and the control device executes the cooperative control function while the two-speed 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. 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 to reduce 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 by pressing the one of the engagement claws radially or axially with the protrusion to retract it from the engagement recess, and then, when the rotation speed of the motor output shaft begins to decrease, performs an inertia process to reduce the drive torque of the drive motor.

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 the torque that can be transmitted without the at least one first friction plate and the at least one second friction plate slipping on each other is equal to or greater than the torque that passes through the friction engagement portion after the two-speed transmission has been switched to the low reduction ratio mode, and then executes a shift completion process that increases the regenerative torque of the drive motor while reducing the braking force applied by the friction brake device.

7. An electric vehicle drive device according to any one of claims 1 to 6, wherein the electric friction clutch device has a return spring that elastically urges the at least one first friction plate and the at least one second friction plate in a direction separating them from each other.

8. An electric vehicle drive device as described in any one of claims 1 to 7, wherein the electric friction clutch device further comprises an elastic biasing mechanism that is provided between the first clutch member or the second clutch member and the friction engagement portion and that elastically biases the at least one first friction plate and the at least one second friction plate in a direction pressing them against each other.

9. An electric vehicle drive device as described in any one of claims 1 to 7, 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 elastically biases the friction engagement portion and the driven cam in directions away from each other.

10. The electric vehicle drive device according to any one of claims 1 to 9, wherein the two-speed transmission further comprises a planetary gear mechanism having a sun gear, a ring gear arranged coaxially around the sun gear, a carrier supported to be capable of relative rotation with respect 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 on the carrier to be capable of rotation about their own central axes, wherein 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 any 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, and a rotating element which is the remaining element among the sun gear, the ring gear, and the carrier excluding the input element and the output element is connected to the rotating member so as to rotate integrally with the rotating member.

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