Drive systems for electric vehicles

Abstract

The present invention provides a drive system for electric vehicles that can reliably prevent shift shock when switching from a high reduction ratio mode to a reduced speed ratio mode. [Solution] During the torque phase while the reduction ratio switching mode is in operation, the control device 4 controls the torque of the input member 6 to increase its torque value, using the value obtained by multiplying the torque value of the input member 6 at the start of the reduction ratio switching mode by the reduction ratio in the high reduction ratio mode as the target value.

Description

[Technical Field]

[0001] This disclosure relates to a drive system for electric vehicles that increases the output torque of an electric motor (reduces its rotation) and transmits it to the drive wheels. [Background technology]

[0002] In response to the recent trend towards reducing fossil fuel consumption, research into electric vehicles and hybrid vehicles has progressed, and some are already being implemented. Unlike internal combustion engines that operate by directly burning fossil fuels, electric motors, which are the power source for electric and hybrid vehicles, have characteristics of torque and rotational speed (revolutions per unit time) of the output shaft that are favorable for automotive use (generally, they generate maximum torque at startup), so it is not always necessary to have a transmission like that of a typical car that uses an internal combustion engine as its power source.

[0003] However, even when using an electric motor as the power source, acceleration and high-speed performance can be improved by installing a transmission. Specifically, by installing a transmission, the relationship between the vehicle's speed and acceleration can be made smoother, similar to that of an automobile equipped with a gasoline engine and a transmission in the power transmission system. This point will be explained with reference to Figure 28.

[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 of the differential gear connected to the drive wheels, the relationship between the acceleration (G) and driving speed (km / h) of the electric vehicle will be as shown by the solid line a in Figure 28. In other words, acceleration performance at low speeds will be excellent, but high-speed driving will be impossible. In contrast, if a power transmission device with a small reduction ratio is placed between the output shaft and the input, this relationship will be as shown by the dashed line b in Figure 28. In other words, high-speed driving will be possible, but acceleration performance at low speeds will be impaired.

[0005] In contrast, by providing a transmission between the output shaft and the input section, and changing the reduction ratio of this transmission according to the vehicle speed, a characteristic can be obtained that is a continuation of the portion to the left of point P in the solid line a and the portion to the right of point P in the dashed line b. This characteristic is almost equivalent to that of a gasoline engine vehicle with a similar output, as shown by the dashed line c in Figure 28, and it can be seen that performance equivalent to that of a gasoline engine vehicle with a transmission in the power transmission system can be obtained in terms of acceleration performance and high-speed performance.

[0006] International Publication No. 2023 / 248571 discloses the structure of a drive system for an electric vehicle in which the torque of the output shaft of an electric motor, which is the drive source, is increased by a two-speed transmission equipped with an electric friction clutch device that can switch between connected and disconnected modes, and a rotational transmission state switching device that can switch between locked mode, one-way clutch mode, and free mode, and transmitted to a differential gear. In this drive system for an electric vehicle, by switching the mode of the electric friction clutch device and the mode of the rotational transmission state switching device, the two-speed transmission can be switched between a reduced speed 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 of the reduced speed ratio mode.

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

[0008] Furthermore, in the electric vehicle drive system described in International Publication No. 2023 / 248571, a reduction ratio switching mode is used to prevent discontinuous changes in the torque of the output component when switching the two-speed transmission from a high reduction ratio mode to a low reduction ratio mode during normal forward driving of the vehicle.

[0009] In the reduction ratio switching mode, when the two-speed transmission is switched from the high reduction ratio mode to the reduced speed ratio mode, the rotational transmission state switching device is first switched to one-way clutch mode. In one-way clutch mode, only rotation of the first member relative to the second member constituting the rotational transmission state switching device in a predetermined direction is permitted, and rotation in the opposite direction to the predetermined direction is prevented.

[0010] Simultaneously with, or after, the rotational transmission state switching device switches to one-way clutch mode, the electric friction clutch device begins switching from disconnection mode to engagement mode. That is, the fastening force of the friction engagement portion of the electric friction clutch device is gradually increased.

[0011] As the input member rotates in the forward direction, the fastening force of the friction engagement portion gradually increases, causing the torque applied to the first member in the direction opposite to the predetermined direction to gradually decrease. At this time, since the rotation transmission state switching device is switched to one-way clutch mode, the first member does not rotate even if torque is applied to it in the direction opposite to the predetermined direction.

[0012] After the torque applied to the first member in the direction opposite to the predetermined direction gradually decreases to zero, the direction of the torque applied to the first member reverses, and when torque is applied to the first member in the predetermined direction, rotation of the first member in the predetermined direction is permitted at that moment. After the first member begins to rotate in the predetermined direction, the rotation transmission state switching device is switched to free mode, and the two-speed transmission is switched to the reduced speed ratio mode. This prevents discontinuous changes in the torque of the output member, while allowing the two-speed transmission to be switched from the high reduction ratio mode to the reduced speed ratio mode. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] International Publication No. 2023 / 248571 [Overview of the project] [Problems that the invention aims to solve]

[0014] The electric vehicle drive system described in International Publication No. 2023 / 248571 has room for improvement in terms of maintaining the torque of the output member more stably and constantly in the reduction ratio switching mode, that is, in terms of more reliably preventing shift shock when switching from the high reduction ratio mode to the low reduction ratio mode.

[0015] In other words, in the electric vehicle drive system described in International Publication No. 2023 / 248571, during the torque phase while the reduction ratio switching mode is being executed, the torque of the input member is increased by an amount corresponding to the increase in the clamping force of the friction engagement part of the electric friction clutch device. This controls the system to maintain the torque of the output member at a nearly constant level, and to match the torque of the input member to the torque of the output member at the end of the torque phase. This suppresses fluctuations in the torque of the output member when transitioning from the torque phase to the inertia phase, thereby preventing the occurrence of shift shock.

[0016] However, as the friction engagement elements constituting the friction engagement part wear down with prolonged use, the deviation of the friction coefficient of the friction engagement part from the assumed value becomes large, making it difficult to maintain a nearly constant torque of the output member by increasing the torque of the input member during the torque phase. Specifically, the amount of increase in the torque of the input member may become excessively large. As a result, when transitioning from the torque phase to the inertia phase, the torque of the output member may temporarily increase, potentially causing a shift shock.

[0017] The present disclosure aims to provide a drive system for electric vehicles that can reliably prevent shift shock when switching from a high reduction ratio mode to a reduced speed ratio mode. [Means for solving the problem]

[0018] An electric vehicle drive system according to one aspect of the present disclosure comprises a drive motor, a two-speed transmission, and a control device.

[0019] The drive motor has a motor output shaft.

[0020] The aforementioned 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.

[0021] The input member is capable of transmitting torque to the motor output shaft.

[0022] The output member is supported in a way that allows for relative rotation with respect to the input member.

[0023] The rotating member is supported in such a way that it can rotate relative to the input member and the output member.

[0024] The electric friction clutch device comprises a first clutch member, a second clutch member, a friction engagement portion, a cam device, and an electric actuator.

[0025] The first clutch member rotates integrally with the rotating member, or is composed of the rotating member itself.

[0026] The second clutch member is supported coaxially with the first clutch member, enabling relative rotation with respect to the first clutch member, and rotates integrally with the input member or the output member, or is composed of the input member or the output member itself.

[0027] The friction engagement portion has at least one first friction plate and at least one second friction plate, which are supported to allow relative displacement in the axial direction, and is provided between the first clutch member and the second clutch member.

[0028] The cam device comprises a drive cam and a driven cam supported to allow relative rotation and axial displacement with respect 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.

[0029] The electric actuator comprises a shift motor and a reduction gear, and the shift motor rotates the drive cam via the reduction gear.

[0030] The electric friction clutch device is configured to switch between a connection mode, in which torque is transmitted between the first clutch member and the second clutch member by pressing the at least one first friction plate and the at least one second friction plate against each other based on expanding or contracting the axial dimension of the cam device, and a disconnection mode, in which torque is not transmitted between the first clutch member and the second clutch member by releasing the force pressing the at least one first friction plate and the at least one second friction plate against each other.

[0031] The rotation transmission state switching device comprises a first member, a second member, a mode select member, a first claw member, a second claw member, a first claw biasing member, and a second claw biasing member.

[0032] The first member has engagement recesses at multiple locations in the circumferential direction.

[0033] The second member is arranged coaxially with the first member.

[0034] The mode select member has multiple protrusions that project radially or axially at multiple locations in the circumferential direction, and rotates or is displaced axially as the drive cam rotates.

[0035] The first claw member has a first base portion pivotally supported by the second member, and a first engaging claw extending from the first base portion toward the first side in the circumferential direction.

[0036] The second claw member has a second base pivotally supported by the second member, and a second engaging claw extending from the second base toward the second side in the circumferential direction.

[0037] The first claw biasing member elastically biases the first engaging claw in a direction that causes it to engage with the engaging recess.

[0038] The second claw biasing member elastically biases the second engaging claw in a direction that causes it to engage with the engaging recess.

[0039] One of the first and second members rotates integrally with the rotating member, or is formed by the rotating member itself. The other of the first and second members is supported so as not to rotate relative to a fixed portion that does not rotate even during use.

[0040] The rotation transmission state switching device is configured to switch between a locked mode, a free mode, and a one-way clutch mode based on the rotation or axial displacement of the mode select member.

[0041] In the lock mode, the protrusion is positioned so as to be offset circumferentially or axially from the first and second engaging claws, and the first and second engaging claws are engaged with the engaging recess, thereby preventing the rotation of one member relative to the other member, regardless of the relative rotation direction of one member relative to the other member.

[0042] In the free mode, the protrusion presses the first engaging claw and the second engaging claw in the radial or axial direction, causing them to retract from the engaging recess, thereby allowing the rotation of the one member relative to the other member regardless of the relative rotation direction of the one member relative to the other member.

[0043] In the one-way clutch mode, the protrusion presses only one of the first and second engaging claws radially or axially, causing it to retract from the engaging recess, while engaging the other engaging claw with the engaging recess. This allows the first member to rotate in a predetermined direction relative to the other member, and prevents the first member from rotating in the opposite direction relative to the other member.

[0044] The control device is equipped with a reduction ratio switching function.

[0045] The reduction ratio switching function switches 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, by switching the mode of the electric friction clutch and the mode of the rotational transmission state switching device based on the rotational drive of the drive cam by the electric actuator.

[0046] Specifically, the reduction ratio switching function switches the two-speed transmission to the high reduction ratio mode by switching the electric friction clutch device to the disconnection mode and the rotation transmission state switching device to the lock mode, and switches the two-speed transmission to the reduced speed ratio mode by switching the electric friction clutch device to the connection mode and the rotation transmission state switching device to the free mode.

[0047] When the control device switches the two-speed transmission from the high reduction ratio mode to the reduced speed ratio mode using the reduction ratio switching function, it simultaneously switches the rotational transmission state switching device to the one-way clutch mode, or, after switching to the one-way clutch mode, it passes through a reduction ratio switching mode that increases the fastening force of the friction engagement portion of the electric friction clutch device.

[0048] Furthermore, during the torque phase while the reduction ratio switching mode is being executed, the control device controls the torque of the input member to increase its torque, using a target value obtained by multiplying the torque value of the input member at the start of the reduction ratio switching mode by the reduction ratio in the high reduction ratio mode.

[0049] In a drive system for an electric vehicle according to one aspect of the present disclosure, the control device can, in the torque phase, when the torque of the input member reaches the target value, maintain the torque of the input member at the target value while reversing the rotation direction of the drive cam from the rotation direction in which the electric friction clutch device transitions to the connection mode to the disconnection mode, and then, when the rotation speed of the input member decreases by a predetermined amount, control the rotation direction of the drive cam back to the rotation direction in which the electric friction clutch device transitions to the connection mode.

[0050] An electric vehicle drive system according to one aspect of the present disclosure may further include an input-side rotation sensor for measuring the rotational speed of the input member and an output-side rotation sensor for measuring the rotational speed of the output member.

[0051] In this case, during the inertia phase while the reduction ratio switching mode is running, the phase of the drive cam with respect to the rotation direction can be controlled so that the torque of the output member does not fluctuate, by utilizing the μ-V characteristic which represents the relationship between the coefficient of friction between the first friction plate and the second friction plate and the difference in rotational speed between the first friction plate and the second friction plate. Furthermore, while monitoring the rotational speed of the input member measured by the input-side rotation sensor and the rotational speed of the output member measured by the output-side rotation sensor, control can be performed to adjust the torque of the input member so that the rotational speed of the input member and the rotational speed of the output member match.

[0052] In one aspect of the present disclosure, the electric friction clutch device may 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 that separates them from each other.

[0053] In a drive system for an electric vehicle according to one aspect of the present disclosure, the electric friction clutch device may further include an elastic biasing mechanism provided between the first clutch member or the second clutch member and the friction engagement portion, which elastically biases the at least one first friction plate and the at least one second friction plate in a direction that causes them to press against each other.

[0054] Alternatively, in a drive system for an electric vehicle according to one aspect of the present disclosure, the electric friction clutch device may further include an elastic biasing mechanism disposed between the friction engagement portion and the driven cam, which elastically biases the friction engagement portion and the driven cam in a direction away from each other.

[0055] In one aspect of the present disclosure, the two-speed transmission may further include a planetary gear mechanism having a sun gear, a ring gear arranged coaxially with the sun gear around the sun gear, a carrier supported to allow relative rotation between the sun gear and the ring gear, and a plurality of planetary gears that mesh with the sun gear and the ring gear and are supported on the carrier to allow rotation about their own central axis.

[0056] In this case, the input element, which is one of the sun gear, the ring gear, and the carrier, rotates integrally with the input member, or is composed of the input member itself.

[0057] An output element, which is one of the sun gear, the ring gear, and the carrier and is a separate element from the input element, rotates integrally with the output member, or is composed of the output member itself.

[0058] The rotating elements, which are the remaining elements of the sun gear, ring gear, and carrier excluding the input element and the output element, rotate integrally with the rotating member, or are composed of the rotating member itself. [Effects of the Invention]

[0059] According to one embodiment of the present invention, a drive system for electric vehicles can reliably prevent shift shock when switching from a high reduction ratio mode to a reduced speed ratio mode. [Brief explanation of the drawing]

[0060] [Figure 1] Figure 1 is a schematic cross-sectional view showing a first example of an electric vehicle drive system according to the embodiments of this disclosure. [Figure 2] Figure 2(A) shows the torque transmission path in the reduced gear ratio mode of the two-speed transmission for the first example, and Figure 2(B) shows the torque transmission path in the high reduction ratio mode of the two-speed transmission for the first example. [Figure 3] Figure 3 is a perspective view showing the two-speed transmission in the first example. [Figure 4] Figure 4 is a cross-sectional view showing the two-speed transmission in the first example. [Figure 5] Figure 5 is a perspective view of the first example, showing the planetary gear mechanism removed from the two-speed transmission. [Figure 6] Figure 6 is a cross-sectional view of the first example, showing the planetary gear mechanism removed from the two-speed transmission. [Figure 7] Figure 7 is an exploded perspective view showing the planetary gear mechanism removed from the two-speed transmission in the first example. [Figure 8] Figure 8 is an enlarged view of section X in Figure 4. [Figure 9] Figure 9 is a perspective view showing the drive cam removed from the electric friction clutch device in the first example. [Figure 10] Figure 10 is an exploded perspective view showing the driven cam and rolling elements removed from the electric friction clutch device in the first example. [Figure 11] Figure 11(A) is a perspective view showing the flange portion and pressing member of the rotating member removed from the two-speed transmission in the first example, and Figure 11(B) is an exploded perspective view showing the flange portion and pressing member removed. [Figure 12]Figures 12(A) to 12(D) are schematic diagrams of the cam mechanism of the electric friction clutch device as viewed from the radially outer side. [Figure 13] Figure 13 is a perspective view of the rotational transmission state switching device, which constitutes the two-speed transmission, as seen from the other axial side, for the first example. [Figure 14] Figure 14 is an exploded perspective view of the rotation transmission state switching device for the first example. [Figure 15] Figure 15 is an end view of the first example, showing the rotation transmission state switching device with the cover removed, viewed from the other axial side. [Figure 16] Figure 16 is an enlarged view of section Y in Figure 15. [Figure 17] Figure 17(A) is a schematic diagram showing the engagement relationship between the first and second engaging claws, the engaging recess, and the projection in the free mode of the rotation transmission state switching device in the first example; Figure 17(B) is a schematic diagram showing the engagement relationship in the locked mode; and Figure 17(C) is a schematic diagram showing the engagement relationship in the one-way clutch mode. [Figure 18] Figure 18 is a schematic diagram illustrating the modes of the electric friction clutch device and the rotational transmission state switching device in the two-speed transmission of the first example. [Figure 19] Figure 19 is a flowchart showing the operation of switching the two-speed transmission from the reduced gear ratio mode to the high reduction ratio mode in the first example. [Figure 20] Figure 20 is a diagram showing the time evolution of each parameter when the two-speed transmission is switched from the high reduction ratio mode to the reduced speed ratio mode in the first example. [Figure 21] Figure 21 is a reference example related to the first example, similar to Figure 20, but showing the case where the coefficient of friction μ is smaller than expected. [Figure 22] Figure 22 is a reference example related to the first example, showing a similar diagram to Figure 20 when the coefficient of friction μ is larger than expected. [Figure 23] Figure 23 is a cross-sectional view showing a portion of a comparative example's two-speed transmission. [Figure 24] Figure 24 is a schematic diagram showing the disconnected and disconnected states of the first friction engagement device and the second friction engagement device for a comparative example two-speed transmission. [Figure 25] Figure 25 is a schematic cross-sectional view showing a second example of an electric vehicle drive system according to the embodiments of this disclosure. [Figure 26] Figure 26(A) shows the torque transmission path in the reduced gear ratio mode of the two-speed transmission that constitutes the second example of the electric vehicle drive system, and Figure 26(B) shows the torque transmission path in the high reduction ratio mode of the two-speed transmission for the second example. [Figure 27] Figure 27 is a cross-sectional view showing the two-speed transmission of the second example. [Figure 28] Figure 28 is a diagram illustrating the effects of incorporating a transmission into a drive system that uses an electric motor as its power source. [Modes for carrying out the invention]

[0061] [Example 1] A first example of an embodiment of this disclosure will be described with reference to Figures 1 to 24.

[0062] The electric vehicle drive system 1 comprises a drive motor 2, a two-speed transmission 3, and a control device 4.

[0063] The drive motor 2 has a motor output shaft 5.

[0064] The two-speed transmission 3 comprises an input member 6, an output member 7, a rotating member 8, an electric friction clutch device 9, and a rotation transmission state switching device 10.

[0065] With respect to the two-speed transmission 3, the axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the input member 6, unless otherwise specified. The axial, radial, and circumferential directions of the input member 6 coincide with the axial, radial, and circumferential directions of the output member 7, and also coincide with the axial, radial, and circumferential directions of the rotating member 8. Furthermore, one side of the axial direction refers to the right side in Figures 1, 2(A), 2(B), 4, 6, 8, and 12(A) to 12(D), and the other side of the axial direction refers to the left side in Figures 1, 2(A), 2(B), 4, 6, 8, and 12(A) to 12(D).

[0066] The two-speed transmission 3 is configured to switch between a high reduction ratio mode, in which the reduction ratio between the input member 6 and the output member 7 is large, and a low reduction ratio mode, in which the reduction ratio between the input member 6 and the output member 7 is small, by switching the torque transmission path by switching the mode of the electric friction clutch device 9 and the rotation transmission state switching device 10. 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 11 by switching the mode of the electric friction clutch device 9 and the rotation transmission state switching device 10.

[0067] The input member 6 is capable of transmitting torque to the motor output shaft 5. Specifically, the input member 6 has an input gear 14 at one end on the axial side that meshes with a drive gear 13 provided on the motor output shaft 5 of the drive motor 2.

[0068] In this example, the input member 6 is rotatably supported by rolling bearings (not shown) or the like, to a fixed part 12 that does not rotate during use, which is made up of a housing that accommodates the two-speed transmission 3. Furthermore, the input member 6 is constructed in a cylindrical (hollow) shape.

[0069] The output member 7 is supported in a way that allows for relative rotation with respect to the input member 6.

[0070] In this example, the output member 7 is arranged coaxially with the input member 6 and is supported radially inside the cylindrical input member 6 via a rolling bearing (not shown) or the like, allowing for relative rotation with respect to the input member 6. The output member 7 also has an output gear 15 at one end on its axial side.

[0071] The rotating member 8 is supported in a way that allows it to rotate relative to the input member 6 and the output member 7.

[0072] In this example, the rotating member 8 is arranged coaxially with the input member 6 and the output member 7, and is rotatably supported with respect to the fixed portion 12 via the rotation transmission state switching device 10, the cam device 31 constituting the electric friction clutch device 9, and the radial bearing 42 for rotatably supporting the drive cam 38 constituting the cam device 31 with respect to the rotating member 8.

[0073] Specifically, the rotating member 8 has a small-diameter flange portion 16 projecting radially outward in the axial middle portion, and a flange portion 17 projecting radially outward in the portion located on the other axial side of the small-diameter flange portion 16. The flange portion 17 has a hollow circular plate-shaped first ring portion 19, a first cylindrical portion 20 bent radially outward from the radially outer end of the first ring portion 19, a hollow circular plate-shaped second ring portion 21 bent radially outward from the other axial end of the first cylindrical portion 20, and a second cylindrical portion 22 bent radially outward from the radially outer end of the second ring portion 21. The first ring portion 19 has multiple partially arc-shaped through holes 18 in the radial middle portion for inserting partially cylindrical portions 67 of the pressing member 62 that constitutes the electric friction clutch device 9.

[0074] In this example, the rotating member 8 is constructed by externally fitting and fixing a stepped cylindrical member 24 to a shaft member 23 having a small-diameter flange portion 16. That is, as shown in Figures 11(A) and 11(B), the stepped cylindrical member 24 has a flange portion 17 and a small-diameter cylindrical portion 25 that is bent axially from the radially inner end of the first ring portion 19 of the flange portion 17 toward the other side. The rotating member 8 is constructed by supporting and fixing the stepped cylindrical member 24 to the shaft member 23, for example, by spline engaging a female spline portion 26 provided on the inner circumferential surface of the small-diameter cylindrical portion 25 with a male spline portion provided on the outer circumferential surface of the shaft member 23. However, the rotating member may also be constructed by joining and fixing the stepped cylindrical member and the shaft member by press-fitting, welding, or the like.

[0075] The electric friction clutch device 9 comprises a first clutch member 27, a second clutch member 28, a friction engagement portion 29, a cam device 31, and an electric actuator 32, and is installed between the rotating member 8 and the input member 6 or output member 7. The electric friction clutch device 9 switches between a connection mode in which torque is transmitted between the first clutch member 27 and the second clutch member 28 and a disconnection mode in which torque is not transmitted.

[0076] The first clutch member 27 is connected to the rotating member 8 so as to rotate integrally with it, or it is formed by the rotating member 8 itself. In this example, the first clutch member 27 is formed by the rotating member 8 itself. In other words, the rotating member 8 and the first clutch member 27 are formed as a single unit.

[0077] The second clutch member 28 is supported coaxially with the first clutch member 27, allowing for relative rotation with respect to the first clutch member 27. Furthermore, the second clutch member 28 is connected to the input member 6 or the output member 7 so as to rotate integrally with it, or it is composed of the input member 6 or the output member 7 itself. In this example, the second clutch member 28 is composed of the input member 6 itself. In other words, the input member 6 and the second clutch member 28 are integrally configured.

[0078] The friction engagement portion 29 has at least one first friction plate 33 and at least one second friction plate 34, which are supported to allow relative axial displacement, and is provided between the first clutch member 27 and the second clutch member 28.

[0079] In this example, at least one first friction plate 33 is composed of multiple first friction plates 33, and at least one second friction plate 34 is composed of multiple second friction plates 34. Specifically, the friction engagement portion 29 is composed of a multi-plate clutch in which multiple first friction plates 33 supported by a first clutch member 27 (rotating member 8) and multiple second friction plates 34 supported by a second clutch member 28 (input member 6) are alternately stacked.

[0080] More specifically, the multiple first friction plates 33 are supported on the outer circumferential surface of the first cylindrical portion 20 in such a way that they can be displaced axially but cannot rotate relative to the first cylindrical portion 20.

[0081] Multiple second friction plates 34 are supported on the inner circumferential surface of the other end of the input member 6 on the axial side, in such a way that they can be displaced in the axial direction but cannot rotate relative to the input member 6.

[0082] The cam device 31 includes a drive cam 38 and a driven cam 39 that is supported to allow relative rotation and relative axial displacement with respect to the drive cam 38. As the drive cam 38 rotates, the cam device 31 expands and contracts the axial distance between the drive cam 38 and the driven cam 39.

[0083] The cam device 31 can be configured in any way as long as the axial distance between the drive cam 38 and the driven cam 39, i.e., the axial dimension of the cam device 31, can be expanded or contracted as the drive cam 38 rotates. For example, the cam device can be configured such as a configuration in which the drive cam surface on the drive cam and the driven cam surface on the driven cam slide directly against each other, a configuration in which a plurality of rolling elements are sandwiched between the drive cam surface on the drive cam and the driven cam surface on the driven cam, or a configuration in which a plurality of rolling elements supported by one of the cams (the drive cam and the driven cam) roll into contact with the cam surface on the other cam (the drive cam and the driven cam).

[0084] In this example, the cam device 31 further includes a drive cam 38 and a driven cam 39, as well as a plurality of rolling elements 40 that are supported by the driven cam 39 and roll in contact with the drive cam surface 52 provided on the drive cam 38.

[0085] The drive cam 38 is supported relative to the rotating member 8 in such a way that it can rotate relative to both the rotating member 8 and the input member 6, but cannot be displaced axially relative to the rotating member 8. Specifically, as shown in Figure 6 and other figures, the drive cam 38 is supported relative to the rotating member 8 by a cylindrical member 41, a radial bearing 42, and an angular contact ball bearing 43, allowing for relative rotation with respect to the rotating member 8. Note that the cylindrical member 41 and the angular contact ball bearing 43 are not shown in Figures 1 to 2(B).

[0086] The cylindrical member 41 has a cylindrical portion 44 and an outward-facing flange portion 45 that is bent radially outward from the other axial end of the cylindrical portion 44. The outward-facing flange portion 45 of the cylindrical member 41 is supported and fixed to the fixing portion 12 by screws or the like.

[0087] The radial bearing 42 has an inner ring 46 fitted and fixed to the other axial end of the rotating member 8, an outer ring 47 fitted and fixed to the cylindrical portion 44 of the cylindrical 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 illustrated example, the radial bearing 42 is made of a double-row deep groove ball bearing using balls as the rolling elements 48. However, the radial bearing is not particularly limited as long as it enables relative rotation between the first member and the cam device and can support the axial biasing force by the elastic biasing mechanism, and can be made of, for example, a deep groove ball bearing, a radial angular contact ball bearing, or a radial tapered roller bearing.

[0088] The angular contact ball bearing 43 has an inner ring 49 fitted and fixed to the cylindrical portion 44 of the cylindrical member 41, an outer ring 50 fitted and fixed to the drive cam 38, and a plurality of balls 51 that are rotatably arranged between the inner ring 49 and the outer ring 50.

[0089] As shown in Figure 9, the drive cam 38 has a drive cam surface 52 on the radially inner portion of one axial side surface, in which equal numbers of recesses and protrusions are alternately arranged in the circumferential direction. The drive cam surface 52 is arranged in the order of a first bottom portion 52a, a gently sloping 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, repeated a number of times equal to the number of rolling elements 40 (3 times in this example), from top to bottom in Figures 12(A) to 12(D).

[0090] Of the drive cam surface 52, the first flat surface portion 52c and the second flat surface portion 52g are located furthest to one side in the axial direction, i.e., at the tip of the convex portion, while the first bottom portion 52a and the second bottom portion 52e are located furthest 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 a virtual plane P perpendicular to the central axis of the drive cam 38 are greater than those of the gently inclined surface portion 52b with respect to the virtual plane P.

[0091] The inclination angle of the gently sloping surface 52b, and the inclination angles of the first intermediate inclined surface 52f and the second intermediate inclined surface 52h are all set to a size that allows the rolling element 40 to move either by rolling down or by riding over it. In this example, the first intermediate inclined surface 52f and the second intermediate inclined surface 52h have opposite inclination directions and the same inclination angles, but the inclination angles can also be made different. In this example, the inclination angle of the gently sloping surface 52b is smaller than the inclination angles of the first intermediate inclined surface 52f and the second intermediate inclined surface 52h, but the inclination angle of the gently sloping surface 52b and the inclination angles of the first intermediate inclined surface 52f and the second intermediate inclined surface 52h can also be made the same.

[0092] Furthermore, the inclination angle of the inclined surface portion 52d with respect to the virtual plane P can be set to any size as long as the rolling element 40 can ride over it.

[0093] In this example, the drive cam 38 has wheel teeth 53, which are helical gears, on its outer circumferential surface, and has pin portions 54 that protrude toward the axial direction at multiple locations (three locations in the illustrated example) in the circumferential direction in the radial middle of one side surface.

[0094] The driven cam 39 is positioned around the rotating member 8 so as to be able to move 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 able to move in the axial direction relative to the fixed portion 12. In this example, the driven cam 39 is supported so as to be able to move in the axial direction relative to the fixed portion 12 by spline-engaging a female spline portion 55 provided on the inner circumferential surface of the driven cam 39 with a male spline portion 56 provided on the outer circumferential surface of one axial side portion of the cylindrical portion 44 of the cylindrical member 41. However, the method of supporting the driven cam with respect to the fixed portion is not particularly limited as long as the driven cam can be supported so as to be able to move only in the axial direction relative to the fixed portion. For example, the driven cam can also be supported so as to be able to move in the axial direction relative to the fixed portion by key-engaging a convex portion provided on one of the driven cam and the fixed portion with a concave groove provided on the other.

[0095] As shown in Figure 10, the driven cam 39 has multiple rectangular holes 57 that penetrate axially at multiple locations (three locations in the illustrated example) in the circumferential direction in the radially intermediate part, and substantially semicircular plate-shaped support plate portions 58a and 58b that protrude from each radial side of the rectangular hole 57 toward the other axial direction. Of the support plate portions 58a and 58b, the radially outer support plate portion 58a has a support hole 59 which is a circular hole that penetrates radially, and the radially inner support plate portion 58b has a support recess 60 with a circular opening on its radially outer surface.

[0096] In this example, the multiple rolling elements 40 are composed of three rolling elements 40. However, the multiple rolling elements 40 can also be composed of two or four or more rolling elements 40.

[0097] Each of the rolling elements 40 has a cylindrical shape. That is, each of the rolling elements 40 is composed of a roller. Each of the rolling elements 40 is supported to rotate freely on the support plate portions 58a and 58b via a cylindrical support shaft 68 and a plurality of rollers 69. Specifically, the outer end of the support shaft 68 in the radial direction with respect to the central axis of the driven cam 39 is fitted and fixed into 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 with respect to the central axis of the driven cam 39 is fitted and fixed into the support recess 60 of the radially inner support plate portion 58b. The plurality of rollers 69 are clamped between the inner circumferential surface of the rolling element 40 and the outer circumferential surface of the axial intermediate portion of the support shaft 68 so as to be able to roll freely. As a result, the rolling element 40 is supported by the driven cam 39 and can freely rotate (rotate) around its rotation axis C, which is oriented radially from the central axis of the driven cam 39.

[0098] With the rolling elements 40 supported by the driven cam 39, one axial portion of the rolling elements 40 is positioned inside the rectangular hole 57. Each of the rolling elements 40 has its outer circumferential surface in rolling contact with the drive cam surface 52 provided on the other axial side of the drive cam 38.

[0099] The cam device 31 rotates the drive cam 38 and increases or decreases the amount by which the rolling elements 40 ride up from the first bottom 52a or the second bottom 52e of the drive cam surface 52, thereby moving the driven cam 39 in the axial direction and expanding or contracting the axial distance between the drive cam 38 and the driven cam 39, i.e., the axial dimension of the cam device 31.

[0100] In this example, rollers are used as rolling elements 40, and the rolling elements 40 are freely supported to rotate (rotate) around a rotation axis C that is oriented radially from the central axis of the driven cam 39 relative to the driven cam 39. Therefore, when the drive cam 38 is rotated, slippage can be prevented at the rolling contact point between the outer 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.

[0101] In contrast, when balls are used as rolling elements in a cam mechanism, slippage may occur at the rolling contact point between the surface of the rolling element and the surface of the driving cam when the driving cam is rotated. If slippage occurs at the rolling contact point between the surface of the rolling element and the surface of the driving cam, the driven cam may not be able to be displaced axially, or the amount of axial displacement of the driven cam may not be sufficiently secured in relation to the amount of rotation of the driving cam. However, balls can also be used as rolling elements in a cam mechanism.

[0102] The electric actuator 32 includes a shift motor 70 and a reduction gear 71, and the shift motor 70 rotates the drive cam 38 of the cam device 31 via the reduction gear 71.

[0103] In this example, the reduction gear 71 is composed of a worm gear reducer. Specifically, the reduction gear 71 is formed by meshing the worm teeth on the outer circumferential surface of a worm 72 connected to the output shaft of the shift motor 70 with the wheel teeth 53 on the outer circumferential surface of a drive cam 38. The worm 72 is rotatably supported relative to the fixed part 12 by a pair of support bearings 73a and 73b. However, the reduction gear 71 can also be composed by meshing a spur gear or bevel gear on the output shaft of the electric motor with a spur gear or bevel gear on the drive cam, or by stretching a belt or chain between the output shaft of the electric motor and the drive cam.

[0104] The electric friction clutch device 9 is configured to be switchable between a connection mode, in which torque is transmitted between the first clutch member 27 and the second clutch member 28 by pressing the first friction plate 33 and the second friction plate 34 against each other based on expanding or contracting the axial dimension of the cam device 31, and a disconnection mode, in which torque is not transmitted between the first clutch member 27 and the second clutch member 28 by releasing the force pressing the first friction plate 33 and the second friction plate 34 against each other.

[0105] In this example, the electric actuator 32 rotates the drive cam 38, and the first friction plate 33 and the second friction plate 34 are pressed against each other based on a reduction in the axial dimension of the cam device 31, i.e., the axial distance between the drive cam 38 and the driven cam 39. The force pressing the first friction plate 33 and the second friction plate 34 against each other is released based on an increase in the axial dimension of the cam device 31.

[0106] The electric friction clutch device 9 may further include, as an optional component, an elastic biasing mechanism 30 provided between the first clutch member 27 or the second clutch member 28 and the friction engagement portion 29, which elastically biases the first friction plate 33 and the second friction plate 34 in a direction that presses them against each other.

[0107] In this case, the electric friction clutch device 9 is configured such that, based on the relative displacement of the driven cam 39 in a direction that increases the axial distance between it and the drive cam 38, the driven cam 39 presses the elastic 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 drive cam 38, the elastic biasing mechanism 30 presses the first friction plate 33 and the second friction plate 34 against each other.

[0108] Alternatively, the electric friction clutch device 9 may further include, as an optional component, an elastic biasing mechanism disposed between the friction engagement portion 29 and the driven cam 39, which elastically biases the friction engagement portion 29 and the driven cam 39 in a direction away from each other.

[0109] In this case, the electric friction clutch device 9 is configured such that, based on the relative displacement of the driven cam 39 in a direction that increases the axial distance between it and the drive cam 38, the driven cam 39 presses the first friction plate 33 and the second friction plate 34 against each other via the elastic biasing mechanism 30, and based on the relative displacement of the driven cam 39 in a direction that decreases the axial distance between it and the drive cam 38, the force pressing the first friction plate 33 and the second friction plate 34 against each other is released.

[0110] In this example, the electric friction clutch device 9 includes an elastic biasing mechanism 30 provided between the first clutch member 27 or the second clutch member 28 and the friction engagement portion 29, which elastically biases the first friction plate 33 and the second friction plate 34 in a direction that causes them to press against each other.

[0111] In this example, the elastic biasing mechanism 30 includes a piston 36 and an elastic member 37.

[0112] The piston 36 is supported to allow axial displacement relative to the rotating member 8. The piston 36 is configured in the shape of a hollow circular plate and is supported around the portion of the rotating member 8 between the small-diameter flange portion 16 and the flange portion 17 in the axial direction, allowing axial displacement relative to the rotating member 8. The piston 36 has its axial end face on the other axial side of the radially outer portion facing the axial side of either the first friction plate 33 or the second friction plate 34, which is located furthest to the axial side of the first friction plate 33 or the second friction plate 34.

[0113] The elastic member 37 is provided between the rotating member 8 and the piston 36. In this example, the elastic member 37 is elastically compressed and sandwiched between the other axial side of the small-diameter flange portion 16 of the rotating member 8 and the axial side of the piston 36. That is, the elastic biasing mechanism 30 elastically biases the first friction plate 33 and the second friction plate 34 in a direction that causes them to press against each other, by pressing the first friction plate 33 or the second friction plate 34, which is on the axial side, toward the other axial side via the piston 36, due to the force with which the elastic member 37 tries to return to its original position.

[0114] The specific configuration of the elastic member is not particularly limited. In this example, the elastic member 37 is composed of at least one disc spring, or two disc springs in the illustrated example. However, the elastic member may also be composed of other elastic members, such as at least one coil spring.

[0115] The elastic biasing mechanism 30 in this example further includes a thrust bearing 61, a pressing member 62, and a preload application means 65 between the driven cam 39 and the piston 36.

[0116] The thrust bearing 61 is provided between a pressing member 62 positioned opposite the piston 36 and the driven cam 39 of the cam device 31. The thrust bearing 61 has a pair of raceway rings 63a and 63b, and a plurality of rolling elements 64 that are rotatably arranged between the pair of raceway rings 63a and 63b. Of the pair of raceway rings 63a and 63b, the raceway ring 63b on the axial side is supported and fixed to the driven cam 39.

[0117] The pressing member 62 has a cylindrical base 66 and a partial cylindrical portion 67 that protrudes in the axial direction from multiple locations (three locations in the illustrated example) in the circumferential direction of one end of the base 66 on the axial side. The axial raceway 63a of a pair of raceway rings 63a, 63b of the thrust bearing 61 is supported and fixed to the other end of the base 66 on the axial side. The partial cylindrical portion 67 is inserted through the through hole 18 of the rotating member 8, and the tip of the partial cylindrical portion 67 (the end on the axial side) faces the radial middle portion of the other side surface of the piston 36 on the axial side.

[0118] The preload application means 65 is positioned between the pressing member 62 and the rotating member 8 and applies preload to the thrust bearing 61. The preload application means 65 is elastically compressed and sandwiched between the pressing member 62 and the other axial side of the first ring portion 19 of the flange portion 17 constituting the rotating member 8. As a result, as shown in Figure 2(A), even when the axial dimension of the cam device 31 is reduced, 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 application means 65 is less than the elastic restoring force of the elastic member 37. The preload application means 65 can be composed of, for example, an elastic member such as an elastomer like rubber, one or more disc springs, one or more coil springs, etc.

[0119] The electric friction clutch device 9 in this example includes, as an optional component, a return spring 35 positioned between the first friction plate 33 and the second friction plate 34, and elastically biasing them in a direction that increases the distance between the first friction plate 33 and the second friction plate 34. This ensures that when the force pressing the first friction plate 33 and the second friction plate 34 against each other is released, the first friction plate 33 and the second friction plate 34 are reliably separated. The elasticity of the return spring 35 is less than the elastic restoring force of the elastic member 37 of the elastic biasing mechanism 30.

[0120] In this example, the electric friction clutch device 9 rotates the drive cam 38 with the electric actuator 32, expanding and contracting the axial dimension of the cam device 31, and displacing the piston 36 of the elastic biasing mechanism 30 relative to the rotating member 8 in the axial direction, thereby enabling switching between a disconnection mode in which torque is not transmitted between the rotating member 8 and the input member 6 and a connection mode in which torque is transmitted.

[0121] First, when switching the electric friction clutch device 9 to a disengagement mode in which torque is not transmitted between the rotating member 8 and the input member 6, the electric actuator 32 rotates the drive cam 38 to position the rolling element 40 on the first flat surface portion 52c or the second flat surface portion 52g of the drive cam surface 52, as shown in Figures 12(B) and 12(D), or to increase the amount that the rolling element 40 rides up onto the gently sloping surface portion 52b, the inclined surface portion 52d, the first intermediate inclined surface portion 52f, or the second intermediate inclined surface portion 52h.

[0122] As a result, the driven cam 39 is moved axially to one side, in the direction that increases the axial distance between it and the drive cam 38. This causes the piston 36 of the elastic biasing mechanism 30 to be pressed axially to one side 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 eventually disappears. As a result, the return spring 35 increases the distance between the first friction plate 33 and the second friction plate 34, and the friction engagement portion 29 is disengaged, causing the electric friction clutch device 9 to switch to disengagement mode.

[0123] In contrast, when the electric friction clutch device 9 is switched to a connection mode that transmits torque between the rotating member 8 and the input member 6, the electric actuator 32 rotates the drive cam 38, so that the rolling element 40 is positioned on the first bottom 52a or second bottom 52e of the drive cam surface 52, or the amount of riding up onto the gently sloping surface 52b, the sloping surface 52d, the first intermediate sloping surface 52f, or the second intermediate sloping surface 52h, as shown in Figures 12(A) and 12(C).

[0124] This reduces the force pressing the piston 36 of the elastic biasing mechanism 30 toward one axial direction by moving the driven cam 39 toward the other axial direction, which reduces the axial distance between it and the drive cam 38. As a result, mainly due to the elastic restoring force of the elastic member 37, the piston 36, the thrust bearing 61, and the pressing member 62 are pressed toward the other axial direction, and the piston 36 presses the first friction plate 33 or the second friction plate 34, which is closest to the one axial direction, toward the other axial direction. As a result, the first friction plate 33 and the second friction plate 34 press against each other, and the friction engagement portion 29 is connected, causing the electric friction clutch device 9 to switch to the connected mode.

[0125] In this example, when the electric friction clutch device 9 is maintained in the disengagement mode, the shift motor 70 must be continuously energized to prevent the piston 36 from moving in the other axial direction due to the elasticity of the elastic member 37. In contrast, when the electric friction clutch device 9 is maintained in the connection mode, the elasticity of the elastic member 37 pushes the piston 36 in the other axial direction, causing the first friction plate 33 and the second friction plate 34 to press against each other. Therefore, when the electric friction clutch device 9 is maintained in the connection mode, it is not necessary to continuously energize the shift motor 70. In other words, the electric friction clutch device 9 in this example is configured as a normally closed type clutch device.

[0126] The rotation transmission state switching device 10 comprises a first member 74, a second member 75, a mode select member 76, a first claw member 89, a second claw member 90, a first claw biasing member 91, and a second claw biasing member 92.

[0127] The first member 74 has multiple engagement recesses 77 in the circumferential direction.

[0128] The second member 75 is arranged coaxially with the first member 74.

[0129] The mode select member 76 has multiple protrusions 100 that project radially or axially at multiple locations in the circumferential direction, and rotates or is displaced axially as the drive cam 38 rotates.

[0130] The first claw member 89 has a first base portion 93 pivotally supported on the second member 75 and a first engaging claw 94 extending from the first base portion 93 toward the first side in the circumferential direction.

[0131] The second claw member 90 has a second base portion 96 pivotally supported on the second member 75, and a second engaging claw 97 extending from the second base portion 96 toward the second side in the circumferential direction.

[0132] The first claw biasing member 91 elastically biases the first engaging claw 94 in a direction that engages it with the engaging recess 77.

[0133] The second claw biasing member 92 elastically biases the second engaging claw 97 in a direction that engages it with the engaging recess 77.

[0134] One of the first member 74 and the second member 75 is connected to the rotating member 8 so as to rotate integrally with it, or is formed by the rotating member 8 itself. The other of the first member 74 and the second member 75 is supported so as not to rotate relative to the fixed part 12, which does not rotate even during use.

[0135] The rotation transmission state switching device 10 is configured to switch between a lock mode in which the rotation of one member relative to the other member is prevented regardless of the relative rotation direction of the one member relative to the other member, a free mode in which the rotation of one member relative to the other member is permitted regardless of the relative rotation direction of the one member relative to the other member, and a one-way clutch mode in which the rotation of one member relative to the other member in a predetermined direction is permitted, and the rotation of one member relative to the other member in the opposite direction to the predetermined direction is prevented.

[0136] Specifically, in lock mode, the protrusion 100 is positioned circumferentially or axially away from the first engaging claw 94 and the second engaging claw 97, and the first engaging claw 94 and the second engaging claw 97 are engaged with the engaging recess 77, thereby preventing the rotation of one member relative to the other member, regardless of the relative rotation direction of one member relative to the other member.

[0137] In free mode, the first engaging claw 94 and the second engaging claw 97 are pressed radially or axially by the protrusion 100 and retracted from the engaging recess 77, thereby allowing the rotation of one member relative to the other member regardless of the relative rotation direction of one member relative to the other member.

[0138] In one-way clutch mode, the protrusion 100 presses only one of the first engaging claws, the first engaging claw 94 and the second engaging claw 97, in the radial or axial direction, causing it to retract from the engaging recess 77, while engaging the other engaging claw with the engaging recess 77. This allows the first member to rotate in a predetermined direction relative to the other member, and prevents the first member from rotating in the opposite direction relative to the other member.

[0139] In this example, the first member 74 is connected to the rotating member 8 so as to rotate integrally with it, and the second member 75 is supported so as not to rotate relative to the fixed part 12, which does not rotate even during use. In addition, the mode select member 76 rotates in conjunction with the rotation of the drive cam 38.

[0140] In this example, the first member 74 has multiple engagement recesses 77 at circumferential locations on its outer surface. Specifically, the first member 74 has a gear-shaped protrusion-recess portion 79 on its outer surface, in which engagement recesses 77 and protrusions 78 are alternately arranged in the circumferential direction.

[0141] Furthermore, the first member 74 has an outer diameter side concave-convex engagement portion 80 on its inner circumferential surface, which is formed by alternately arranging concave and convex portions in the circumferential direction. The first member 74 is supported in a way that prevents relative rotation with respect to the rotating member 8 by engaging the outer diameter side concave-convex engagement portion 80 with an inner diameter side concave-convex engagement portion 81 provided on the outer circumferential surface of the second cylindrical portion 22 of the rotating member 8. In other words, the first member 74 rotates integrally with the rotating member 8.

[0142] The second member 75 is supported around the first member 74 coaxially with the first member 74 and is capable of relative rotation with respect 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 surface of the convex portion 78, with a gap in between. The second member 75 has an inner diameter side concave-convex engagement portion 82 on its outer circumferential surface, which has concave and convex portions arranged alternately in the circumferential direction. The second member 75 is supported in a way that prevents relative rotation with respect to the fixed portion 12 by engaging the inner diameter side concave-convex engagement portion 82 with an outer diameter side concave-convex engagement portion provided on the inner circumferential surface of the fixed portion 12. That is, the second member 75 does not rotate even when the two-speed transmission 3 is in use.

[0143] The second member 75 comprises a base portion 83 having a rectangular cross-sectional shape, and a cylindrical portion 84 that protrudes around the entire circumference from the radially outer end of the side surface on the other axial side of the base portion 83 toward the other axial side.

[0144] The base portion 83 has multiple (six in the illustrated example) first retaining recesses 85 and second retaining recesses 86 arranged alternately in the circumferential direction.

[0145] Each first retaining recess 85 opens onto the inner circumferential surface and the other axial side of the base 83. Each first retaining recess 85 comprises a spring retaining portion 87a and a base portion 88a. The spring retaining portion 87a has a substantially rectangular opening shape, with its major axis positioned so that it extends radially outward as it moves toward one circumferential side (the clockwise front side in Figures 15 to 17) when viewed from the other axial side. The base portion 88a has a substantially circular opening shape when viewed from the other axial side and is positioned adjacent to the other circumferential side (the clockwise rear side in Figures 15 to 17) of the spring retaining portion 87a.

[0146] Each second retaining recess 86 opens onto the inner circumferential surface and the other axial side of the base 83. Each second retaining recess 86 has a shape symmetrical to the first retaining recess 85 with respect to a virtual plane containing the central axis of the second member 75 when viewed from the other axial side. That is, each second retaining recess 86 comprises a spring retaining portion 87b and a base portion 88b. The spring retaining portion 87b has a substantially rectangular opening shape, with its major axis positioned in a direction that extends radially outward as it approaches the other circumferential side when viewed from the other axial side. The base portion 88b has a substantially circular opening shape when viewed from the other axial side and is positioned adjacent to one circumferential side of the spring retaining portion 87a.

[0147] The rotation transmission state switching device 10 in this example has a first claw member 89 and a second claw member 90, and a first claw biasing member 91 and a second claw biasing member 92. In this example, the rotation transmission state switching device 10 has multiple and equal numbers of each of the first claw member 89 and the second claw member 90, and the first claw biasing member 91 and the second claw biasing member 92.

[0148] The first base portion 93 of each first claw member 89 is configured in a substantially cylindrical shape and is supported (pivoted) on the base portion 88a of the first retaining recess 85 so as to be able to swing about a pivot parallel to the central axis of the second member 75.

[0149] Each first claw member 89 has a first engaging claw 94 which is substantially flat and extends from the first base 93 toward one side in the circumferential direction. The other axial side portion of the first engaging claw 94 is positioned opposite (engaged with) the outer circumferential surface of the annular projection 95 of the mode select member 76, and the one axial side portion is positioned opposite (engaged with) the recessed portion 79 of the first member 74 (engaged to enable engagement and disengagement with the engaging recess 77).

[0150] The second base portion 96 of each second claw member 90 is configured in a substantially cylindrical shape and is supported on the base portion 88b of the second retaining recess 86 so as to be able to swing about a pivot parallel to the central axis of the second member 75.

[0151] Each second claw member 90 has a second engaging claw 97 which is substantially flat and extends from the second base 96 toward the other side in the circumferential direction. The second engaging claw 97 has its axial other side facing the outer circumferential surface of the annular projection 95 of the mode select member 76, and its axial one side facing the recessed portion 79 of the first member 74.

[0152] The first claw biasing member 91 applies a biasing force to the first claw member 89 in a direction that causes the first claw member 89 to swing clockwise around the central axis (pivot) of the first base 93 as shown in Figure 16. Specifically, the first claw biasing member 91 is made 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 87a of the first holding recess 85 and the radially outer surface of the first engaging claw 94.

[0153] The second claw biasing member 92 applies a biasing force to the second claw member 90 in a direction that causes the second claw member 90 to swing counterclockwise around the central axis of the second base 96 as shown in Figure 16. Specifically, the second claw biasing member 92 is made of an elastic member such as a coil spring and is held in an elastically compressed state between the bottom surface (the surface facing radially inward) of the spring holding portion 87b of the second holding recess 86 and the radially outer surface of the second engaging claw 97.

[0154] As shown in Figure 14, the mode select member 76 comprises a substantially circular plate-shaped base portion 98 and an annular projection portion 95 that protrudes around the entire circumference from the radial middle portion of the side surface on one axial side (left side in Figure 14) of the base portion 98 toward the axial side.

[0155] The base portion 98 has plate-side engagement holes 99 at multiple equally spaced locations in the circumferential direction in the radially intermediate part of the other side of the axial portion (three locations in the illustrated example). The axial end of the pin portion 54 is fitted (engaged) into each plate-side engagement hole 99 without any 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).

[0156] The annular projection 95 has multiple projections 100 on its outer surface in the circumferential direction, projecting radially outward. That is, the annular projection 95 has a gear-shaped uneven surface 101 on its outer surface, in which projections 100 and recesses are alternately arranged in the circumferential direction.

[0157] The first member 74 and the second member 75 and the mode select member 76 are combined by the cover 102 and the retaining ring 103 so as to be rotatable relative to each other, but so as not to be displaced relative in the axial direction (to prevent accidental separation in the axial direction), thereby constituting the rotation transmission state switching device 10.

[0158] Specifically, with the first member 74 positioned radially inward of one axial side portion of the base 83 of the second member 75, a ring-shaped cover 102 is supported and fixed to one axial side of the second member 75 by screws, and the other axial side of the radially inward portion of the cover 102 is positioned opposite one axial side of the first member 74. This prevents the first member 74 from being displaced in one axial direction relative to the second member 75.

[0159] The annular projection 95 of the mode select member 76 is positioned radially inward of the axially opposite portion of the base 83 of the second member 75, the tip surface (axially opposite side) of the annular projection 95 is in sliding contact or close proximity to the axially opposite side of the first member 74, and the axially opposite side of the radially outer portion of the base 98 is in sliding contact or close proximity to the axially opposite side of the base 83 of the second member 75, while the retaining ring 103 is locked to the axially opposite end 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 being displaced axially to the other side relative to the second member 75.

[0160] The rotation transmission state switching device 10 in this example is configured to switch between free mode, locked mode, and one-way clutch mode by switching the engagement state between the first engaging claw 94 of the first claw member 89 and the engaging recess 77 of the first member 74, and the engagement state between the second engaging claw 97 of the second claw member 90 and the engaging recess 77, based on the rotation of the mode select member 76.

[0161] In free mode, the circumferential phase of the mode select member 76 relative to the second member 75 is adjusted, and as shown in Figure 17(A), the projection 100 pushes the first engaging claw 94 radially outward against the elasticity of the first claw biasing member 91, and pushes the second engaging claw 97 radially outward against the elasticity of the second claw biasing member 92. As a result, the engagement between the engaging recess 77 of the first member 74 and the first engaging claw 94 and the second engaging claw 97 is disengaged. In this state, rotation of the first member 74 relative to the second member 75 is permitted regardless of the relative rotation direction of the first member 74 and the second member 75. That is, rotation of the first member 74 relative to the fixed portion 12 is permitted regardless of the rotation direction of the first member 74.

[0162] In lock mode, the circumferential phase of the mode select member 76 relative to the second member 75 is adjusted so that the protrusion 100 is positioned circumferentially away from the first engaging claw 94 of the first claw member 89 and the second engaging claw 97 of the second claw member 90, as shown in Figure 17(B). That is, the phase of the recess of the uneven portion 101 is aligned with that of the first engaging claw 94 and the second engaging claw 97 in the circumferential direction. As a result, the engaging recess 77 of the first member 74 engages with the first engaging claw 94 and the second engaging claw 97. In this state, regardless of the relative rotation direction of the first member 74 and the second member 75, rotation of the first member 74 relative to the second member 75 is prevented. That is, regardless of the rotation direction of the first member 74, rotation of the first member 74 relative to the fixed portion 12 is prevented.

[0163] In 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 17(C), the projection 100 pushes only the second engaging claw 97 radially outward against the elasticity of the second claw biasing member 92. As a result, the engaging recess 77 of the first member 74 engages with the first engaging claw 94, and the engagement between the engaging recess 77 and the second engaging claw 97 is disengaged. In this state, only rotation of the first member 74 relative to the second member 75 in the predetermined direction (clockwise in Figure 17(C)) is permitted, and rotation in the opposite direction (counterclockwise in Figure 17(C)) is prevented.

[0164] In other words, when the first member 74 attempts to rotate relative to the second member 75 in the predetermined direction, the protrusion 78 of the recessed portion 79 pushes the first engaging claw 94 radially outward against the elasticity of the first claw biasing member 91. As a result, rotation of the first member 74 in the predetermined direction is permitted. Conversely, when the first member 74 attempts to rotate relative to the second member 75 in the opposite direction to the predetermined direction, the engagement between the engaging recess 77 and the first engaging claw 94 prevents the first member 74 from rotating in the opposite direction. In short, the rotation transmission state switching device 10 operates as a ratchet-type one-way clutch.

[0165] The predetermined direction mentioned above coincides with the forward rotation direction of the input member 6. The forward rotation direction of the input member 6 refers to the direction of rotation of the input member 6 when the automobile is moved forward.

[0166] The two-speed transmission 3 is configured to switch between a high reduction ratio mode, in which the reduction ratio between the input member 6 and the output member 7 is large, and a low reduction ratio mode, in which the reduction ratio between the input member 6 and the output member 7 is small, by switching the mode of the electric friction clutch device 9 and the rotation transmission state switching device 10.

[0167] The two-speed transmission 3 in this example further comprises a planetary gear mechanism 11 as an optional component. That is, the two-speed transmission 3 in 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 9 and the mode of the rotation transmission state switching device 10, thereby switching the torque transmission path transmitted through the planetary gear mechanism 11.

[0168] The planetary gear mechanism 11 includes a sun gear 104, a ring gear 105, a carrier 106, and a plurality of planetary gears 107.

[0169] The ring gear 105 is positioned around the sun gear 104, coaxially with the sun gear 104.

[0170] The carrier 106 is supported coaxially with the sun gear 104 and the ring gear 105, and is capable of relative rotation with respect to the sun gear 104 and the ring gear 105.

[0171] Multiple planetary gears 107 mesh with the sun gear 104 and the ring gear 105, and are supported by the carrier 106, enabling them to rotate (spin) around their own central axis.

[0172] Each of the multiple planetary gears 107 can be composed of a planetary gear that meshes with both the sun gear 104 and the ring gear 105. In other words, the planetary gear mechanism 11 can be composed of a single-pinion type planetary gear mechanism. Alternatively, each of the multiple 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 also meshes with the first planetary gear. In other words, the planetary gear mechanism 11 can be composed of a double-pinion type planetary gear mechanism.

[0173] In the two-speed transmission 3, the input member 6, output member 7, the first friction plate 33 and second friction plate 34 of the electric friction clutch device 9, and the first member 74 and second member 75 of the rotational transmission state switching device 10 are connected to the sun gear 104, ring gear 105, carrier 106, or fixed part 12 so that the reduction ratio between the input member 6 and the output member 7 can be switched between two stages, high and low, by switching the mode of the electric friction clutch device 9 and the rotational transmission state switching device.

[0174] Specifically, an input element, which is one of the sun gear 104, ring gear 105, and carrier 106, rotates integrally with the input member 6, or is composed of the input member 6 itself. An output element, which is one of the sun gear 104, ring gear 105, and carrier 106, and is a different element from the input element, rotates integrally with the output member 7, or is composed of the output member 7 itself. Furthermore, among the sun gear 104, ring gear 105, and carrier 106, the rotating elements, which are the remaining elements excluding the input element and the output element, rotate integrally with the rotating member 8, or is composed of the rotating member 8 itself.

[0175] For example, the ring gear 105 may rotate integrally with the input member 6, or be composed of the input member 6 itself; the carrier 106 may rotate integrally with the output member 7, or be composed of the output member 7 itself; and the sun gear 104 may rotate integrally with the rotating member 8, or be composed of the rotating member 8 itself.

[0176] Alternatively, the sun gear 104 may rotate integrally with the input member 6, or be composed of the input member 6 itself; the carrier 106 may rotate integrally with the output member 7, or be composed of the output member 7 itself; and the ring gear 105 may rotate integrally with the rotating member 8, or be composed of the rotating member 8 itself.

[0177] Alternatively, the sun gear 104 may rotate integrally with the input member 6, or be composed of the input member 6 itself; the ring gear 105 may rotate integrally with the output member 7, or be composed of the output member 7 itself; and the carrier 106 may rotate integrally with the rotating member 8, or be composed of the rotating member 8 itself.

[0178] In this example, the ring gear 105 rotates integrally with the input member 6, or is composed of the input member 6 itself; the carrier 106 rotates integrally with the output member 7, or is composed of the output member 7 itself; and the sun gear 104 rotates integrally with the rotating member 8, or is composed of the rotating member 8 itself.

[0179] More specifically, the sun gear 104 is provided at one end of the rotating member 8 on the axial side.

[0180] The ring gear 105 is located in the axial middle portion of the input member 6.

[0181] The carrier 106 is integrated with the output component 7.

[0182] Furthermore, each of the multiple planetary gears 107 meshes with both the sun gear 104 and the ring gear 105, and is supported by the carrier 106 so that it can rotate (spin) around its own central axis. In other words, in this example, the planetary gear mechanism 11 is composed of a single-pinion type planetary gear mechanism.

[0183] The electric vehicle drive system 1 in this example further includes a torque transmission mechanism 109 that transmits torque between the output member 7 and the drive wheels 108. Specifically, the torque transmission mechanism 109 is composed of a differential that distributes the torque of the output member 7 to a pair of drive wheels 108. By meshing the output gear 15 of the output member 7 with the ring gear 110 of the differential that constitutes the torque transmission mechanism 109, torque can be transmitted between the output member 7 and the drive wheels 108.

[0184] The control device 4 is equipped with a reduction ratio switching function that switches the two-speed transmission 3 between a high reduction ratio mode and a low reduction ratio mode based on the rotational drive of the drive cam 38 by the electric actuator 32.

[0185] Also, in this example, the control device 4 obtains the output torque of the drive motor 2, that is, the torque of the motor output shaft 5, based on the current value of the drive motor 2, and further, based on the obtained output torque of the drive motor 2 and the reduction ratio between the motor output shaft 5 and the input member 6, the torque T in of the input member 6 can be obtained. The reduction ratio between the motor output shaft 5 and the input member 6 is the reduction ratio of the speed reducer formed by meshing the drive gear 13 and the input gear 14.

[0186] The drive device 1 for an electric vehicle in this example has an input-side rotation sensor (not shown) for measuring the rotational speed R in of the input member 6, and an output-side rotation sensor (not shown) for measuring the rotational speed R out of the output member 7. In this example, the control device 4 can obtain the rotational speed R in of the input member 6 based on the output signal of the input-side rotation sensor, and can obtain the rotational speed R out of the output member 7 based on the output signal of the output-side rotation sensor.

[0187] The input-side rotation sensor can be installed at a location where it directly measures the rotational speed R in of the input member 6, or can also be installed at a location where it indirectly measures the rotational speed R in of the input member 6 through the rotational speed of another member that rotates synchronously with the input member 6. In this example, the input-side rotation sensor is installed at a location where it measures the rotational speed of the motor output shaft 5 that rotates synchronously with the input member 6. That is, in this example, the control device 4 obtains the rotational speed of the motor output shaft 5 based on the output signal of the input-side rotation sensor, and further, based on the obtained rotational speed of the motor output shaft 5 and the reduction ratio between the motor output shaft 5 and the input member 6, the rotational speed R in of the input member 6 can be obtained.

[0188] The output-side rotation sensor can be installed at a location where it directly measures the rotational speed R out of the output member 7, or can also be installed at a location where it measures the rotational speed R outIt can also be installed in a location where the rotation speed is measured indirectly via the rotation speed of another member that rotates in sync with the output member 7. In this example, the output-side rotation sensor measures the rotation speed R of the output member 7. out It is installed at the location where the measurement is taken directly.

[0189] <Reduced Speed ​​Ratio Mode> To switch the two-speed transmission 3 to the reduced gear ratio mode, the electric friction clutch device 9 is switched to the connected mode, and the rotational transmission state switching device 10 is switched to the free mode.

[0190] Specifically, the electric friction clutch device 9 is switched to the connected mode based on the rotation of the drive cam 38 by the electric actuator 32, which reduces the axial dimension of the cam device 31. As a result, the input member 6 and the rotating member 8 rotate together, and the sun gear 104 and the ring gear 105 rotate together.

[0191] When the electric friction clutch device 9 is switched to connection mode, the rotation transmission state switching device 10 is switched 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 of the first member 74 and the second member 75, based on the adjustment of the circumferential phase of the mode select member 76 relative to the second member 75 by the rotation of the drive cam 38. As a result, rotation of the rotating member 8 relative to the fixed part 12 is permitted, and rotation of the sun gear 104 is permitted.

[0192] In the reduced speed ratio mode, the rotation direction and rotation speed of the sun gear 104, ring gear 105, and carrier 106 become the same, and the entire planetary gear mechanism 11 rotates as a single unit, in a so-called glued state. Therefore, the torque T of the input member 6 in As shown by the thick lines in Figure 2(A), the signal is transmitted in the order of input member 6, carrier 106, and output member 7, and is extracted from output member 7.

[0193] <High reduction ratio mode> To switch the two-speed transmission 3 to the high reduction ratio mode, the electric friction clutch device 9 is switched to the disengagement mode, and the rotational power transmission state switching device 10 is switched to the lock mode.

[0194] Specifically, the drive cam 38 is rotated by the electric actuator 32, and based on expanding the axial dimension of the cam device 31, the electric friction clutch device 9 is switched to the disengagement mode. As a result, the input member 6 and the rotating member 8 become capable of relative rotation, and the sun gear 104 and the ring gear 105 become capable of relative rotation.

[0195] Simultaneously with switching the electric friction clutch device 9 to the disengagement mode, by the rotation of the drive cam 38, the rotational power transmission state switching device 10 is switched to the lock mode in which the rotation of the first member 74 with respect to the second member 75 is blocked regardless of the relative rotation direction between the first member 74 and the second member 75. As a result, the rotation of the rotating member 8 with respect to the fixed portion 12 is blocked, and the rotation of the sun gear 104 is blocked.

[0196] In the high reduction ratio mode, the torque T of the input member 6 in is transmitted in the order of the input member 6, the ring gear 105, the rotational movement of the planetary gear 107, the orbital movement of the planetary gear 107 based on the meshing with the sun gear 104, the carrier 106, and the output member 7, and is taken out from the output member 7 as shown by the thick line in Fig. 2(B). The reduction ratio i between the input member 6 and the output member 7 in the high reduction ratio mode is determined by the gear ratio of the ring gear 105 and the sun gear 104 (the number of teeth of the ring gear 105 / the number of teeth of the sun gear 104).

[0197] In the drive device 1 for an electric vehicle of this example, based on rotating and driving one drive cam 38 by one electric actuator 32, by switching the mode of the electric friction clutch device 9 and the mode of the rotation transmission state switching device 10, the reduction ratio between the input member 6 and the output member 7 can be switched between two levels of high and low. Specifically, for example, in the region where the power input to the input member 6 is low speed and high torque, the two-speed transmission 3 is switched to the high reduction ratio mode, and in the region of high speed and low torque, it is switched to the low reduction ratio mode. For this reason, the acceleration performance and high-speed performance when an electric vehicle or a hybrid vehicle is running with only an electric motor as a drive source are such that the left side portion of the solid line a in FIG. 28 of the above-mentioned compared with the point P and the right side portion of the chain line b compared with the point P are made continuous, and it can be made close to the gasoline engine vehicle shown by the broken line c in FIG. 28.

[0198] In the drive device 1 for an electric vehicle of this example, a hydraulic system for controlling a friction engagement device such as a clutch or a brake is not required. For this reason, in an electric vehicle or a hybrid vehicle, the system can be simplified, the cost can be reduced, and the power consumption performance can be improved.

[0199] In the drive device 1 for an electric vehicle, when the control device 4 switches the two-speed transmission 3 from the high reduction ratio mode to the low reduction ratio mode, it switches the rotation transmission state switching device 10 to the one-way clutch mode at the same time, or after switching to the one-way clutch mode, it is configured to pass through a reduction ratio switching mode for increasing the fastening force F C of the friction engagement portion 29 of the electric friction clutch device 9. Thereby, it prevents the torque T out of the output member 7 from changing discontinuously. The fastening force F C means the force with which the first friction plate 33 and the second friction plate 34 press against each other in the axial direction.

[0200] <Reduction ratio switching mode> When the two-speed transmission 3 is switched from the high reduction ratio mode to the reduced speed ratio mode during normal forward driving of the vehicle, first, based on adjusting the circumferential phase of the mode select member 76 with respect to the second member 75, the projection 100 pushes only the second engaging claw 97 radially outward against the elasticity of the second claw biasing member 92, as shown in Figure 17(C). As a result, only the first engaging claw 94 engages with the engaging recess 77 of the first member 74, and the rotation transmission state switching device 10 switches to a one-way clutch mode that allows the first member 74 to rotate only in the predetermined direction (the predetermined direction in Figure 17(C)) relative to the second member 75, and prevents rotation in the opposite direction.

[0201] Simultaneously with, or after, the rotation transmission state switching device 10 switches to one-way clutch mode, the electric friction clutch device 9 starts switching from disconnection mode to connection mode. During the switching of the electric friction clutch device 9 from disconnection mode to connection mode, based on the rotation of the drive cam 38, the rolling elements 40 move down the gently sloping surface portion 52b of the drive cam surface 52, as shown in Figures 12(B) and 12(A). As the amount of the rolling elements 40 riding up from the first bottom portion 52a of the drive cam surface 52 gradually decreases, the force pressing the first friction plate 33 and the second friction plate 34 together in the axial direction, i.e., the fastening force F of the friction engagement portion 29, is generated. C The force gradually increases. At this time, the input member 6 rotates while sliding (making contact with) the axial sides of the second friction plate 34 against the axial sides of the first friction plate 33.

[0202] During rotation of the input member 6 in the forward direction, the fastening force F of the friction engagement portion 29 CAs the torque gradually increases, the torque applied to the first member 74 of the rotational transmission state switching device 10 in the direction opposite to the predetermined direction gradually decreases. At this time, since the rotational transmission state switching device 10 is switched to one-way clutch mode, even if torque is applied to the first member 74 in the direction opposite to the predetermined direction, the first member 74 does not rotate. After the torque applied to the first member 74 in the direction opposite to the predetermined direction gradually decreases to zero, the direction of the torque applied to the first member 74 reverses, and when torque is applied to the first member 74 in the predetermined direction, rotation of the first member 74 in the predetermined direction is permitted at that moment. After that, the rotational transmission state switching device 10 is switched to free mode, and the two-speed transmission 3 is switched to the reduced speed ratio mode.

[0203] In the electric vehicle drive system 1 of this example, the transition from the high reduction ratio mode to the reduced speed ratio mode during normal forward driving passes through a reduction ratio switching mode. This suppresses the shift shock associated with mode switching while also suppressing torque loss. The reason for this will be explained with reference to Figures 23 and 24.

[0204] Figure 23 shows a part of the comparative example's two-speed transmission. The comparative example's two-speed transmission includes a first friction engagement device 201 that switches between relative rotation between the input member 6 and the rotating member 8, in other words, between relative rotation between the ring gear 105 and the sun gear 104, and a second friction engagement device 202 that switches between rotation of the rotating member 8 relative to the fixed part 12, in other words, between rotation of the sun gear 104. That is, the comparative example's two-speed transmission employs a second friction engagement device 202 that switches modes by pressing or separating the first friction plate 33 and the second friction plate 34, instead of the rotation transmission state switching device 10 of the two-speed transmission 3 of this example.

[0205] In the comparative example, the mode of the first friction engagement device 201 and the mode of the second friction engagement device 202 are switched based on the rotational drive of the drive cam 38z of the cam device 31z by an electric actuator, thereby displacing the first driven cam 203 and the second driven cam 204 in the axial direction. The first driven cam 203 and the second driven cam 204 are displaced at different phases from each other as the drive cam 38z rotates (they are displaced (moving forward and backward) in opposite directions with respect to the axial direction).

[0206] In the comparative example's two-speed transmission, during the switch from a high reduction ratio mode with a large reduction ratio to a low reduction ratio mode with a small reduction ratio, as shown in Figure 24, 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. Therefore, during the switch 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, causing a torque loss between the rotating member 8 and the fixed part 12.

[0207] Furthermore, in the comparative example's two-speed transmission, as the fastening force of the first friction engagement device 201 gradually increases, the torque applied to the sun gear 104 in the direction opposite to the predetermined direction gradually decreases to zero, and then the direction of the torque applied to the sun gear 104 reverses. However, in the comparative example's two-speed transmission, at the moment when the direction of the torque applied to the sun gear 104 reverses and the rotation direction of the planetary gear 107 coincides with the rotation direction of the sun gear 104, the fastening force of the second friction engagement device 202 cannot be made sufficiently large. As a result, the sun gear 104 is dragged against the fixed part 12, and torque loss occurs between the sun gear 104 and the fixed part 12.

[0208] In contrast, in this example, the rotation transmission state switching device 10 is set to one-way clutch mode before the electric friction clutch device 9 begins to switch from the disconnection mode to the connection mode in order to switch from the high reduction ratio mode to the reduced speed ratio mode based on the rotation of the drive cam 38. For this reason, the fastening force F of the friction engagement part 29 is set in order to switch the electric friction clutch device 9 from the disconnection mode to the connection mode. C The torque is gradually increased so that the sun gear 104 can rotate in the predetermined direction at the moment the direction of the torque applied to the sun gear 104 reverses. This makes it possible to suppress the shift shock associated with mode switching while suppressing torque loss in the two-speed transmission 3.

[0209] In the reduction ratio switching mode, the reduction ratio between the input member 6 and the output member 7 is determined by the fastening force F of the friction engagement portion 29. C However, when the torque loss at the contact points between the axial sides of the first friction plate 33 and the axial sides of the second friction plate 34 is small enough that no torque loss occurs, the reduction ratio i is the same as in the high reduction ratio mode. On the other hand, the fastening force F of the friction engagement portion 29 C However, when the friction ratio increases to a size sufficient to transmit torque without slippage at the contact points between the axial sides of the first friction plate 33 and the axial sides of the second friction plate 34, it is the same as the reduction ratio in the reduced speed ratio mode, i.e., 1.

[0210] Fastening force F of friction engagement portion 29 C However, in a state where slippage occurs at the contact points between the axial sides of the first friction plate 33 and the axial sides of the second friction plate 34, the reduction ratio between the input member 6 and the output member 7 is equal to the torque T of the input member 6. in or rotation speed R in The value will depend on factors such as these.

[0211] When the input member 6 is rotating in the forward direction, and during the switching from the high reduction ratio mode to the reduction ratio switching mode, a torque is applied to the second member 75 of the rotation transmission state switching device 10 in the direction opposite to the predetermined direction. In the rotation transmission state switching device 10, rotation of the second member 75 in the direction opposite to the predetermined direction is prevented even during the switching from the lock mode to the one-way clutch mode. That is, during the switching from the high reduction ratio mode to the reduction ratio switching mode, the reduction ratio between the input member 6 and the output member 7 is the same as the reduction ratio i in the high reduction ratio mode.

[0212] When the input member 6 is rotating in the forward direction, and during the switching from the reduction ratio switching mode to the reduced speed ratio mode, torque is applied to the second member 75 of the rotation transmission state switching device 10 in the predetermined direction. In the rotation transmission state switching device 10, rotation of the second member 75 in the predetermined direction is permitted even during the switching from the one-way clutch mode to the free mode.

[0213] Furthermore, in order to more reliably prevent shift shock when the two-speed transmission 3 is switched from high reduction ratio mode to low reduction ratio mode by the reduction ratio switching function, the control device 4 controls the torque T of the input member 6 at the start of the reduction ratio switching mode during the torque phase while the reduction ratio switching mode is being executed. in Value (reference value) T B The value T is obtained by multiplying this by the reduction ratio i in high reduction ratio mode. G With this as the target value, the torque T of the input member 6 in Control is implemented to increase it.

[0214] An example of this control will be explained using Figures 19 and 20. The following example shows the torque T of the output member 7 before and after switching from the high reduction ratio mode to the reduced speed ratio mode. out This is an example of maintaining a nearly constant value.

[0215] When switching from the high reduction ratio mode to the reduced speed ratio mode is initiated based on conditions such as the vehicle's speed and accelerator opening, first, in (S1), the torque T of the input member 6 at the start of the switching, i.e., at the start of the reduction ratio switching mode, is measured. in The value of the reference value T B The reference value T B The value obtained by multiplying this by the reduction ratio i in high reduction ratio mode is the target value T of the torque of the input member 6 at the time the switch from high reduction ratio mode to reduced speed ratio mode is completed. G Set to this.

[0216] Next, in (S2), the electric actuator 32 rotates the drive cam 38 in the direction that the electric friction clutch device 9 transitions to the connection mode, thereby switching the rotation transmission state switching device 10 to one-way clutch mode, and the phase (cam angle) of the rotation direction of the drive cam 38 is set to the clutch touch point θ f Move it to [location].

[0217] Clutch touch point θ f This is the point at which the elastic biasing mechanism 30 begins to generate a force that presses the first friction plate 33 and the second friction plate 34 against each other. In other words, the clutch touch point θ f This is the point where the axial end of the piston 36 and the first friction plate 33 or the second friction plate 34, which is located furthest to the axial side, begin to come into contact.

[0218] In this example, the control device 4 is determined by the phase (cam angle) of the rotation direction of the drive cam 38 and the clutch torque capacity T, which is the magnitude of the torque that can be transmitted by the friction engagement part 29, obtained through prior experiments. C Map M representing the relationship C Using the clutch touch point θ, f We will find map M. C In this context, the clutch touch point θ f The clutch torque capacity T CIt can be obtained as the phase (cam angle) regarding the rotation direction of the drive cam 38 when switching from 0 to a finite value. Note that in International Publication No. 2023 / 248571, there is a function for detecting the clutch touch point θ f That is, even when the clutch touch point θ f changes due to wear of the friction engagement elements constituting the friction engagement portion, etc., a two-speed transmission capable of detecting the changed clutch touch point θ f is disclosed. When implementing the present disclosure, this function can be added to the two-speed transmission, and the clutch touch point θ f can also be obtained by this function.

[0219] When the phase (cam angle) regarding the rotation direction of the drive cam 38 is moved to the clutch touch point θ f it shifts to the torque phase.

[0220] In the torque phase, the drive cam 38 is continuously rotationally driven in the direction in which the electric friction clutch device 9 shifts to the connection mode, and the fastening force F C of the friction engagement portion 29 is increased (S3-1).

[0221] In this example, the rotational speed of the drive cam 38 in the torque phase (S3-1) is made smaller than the rotational speed of the drive cam 38 when moving the phase (cam angle) regarding the rotation direction of the drive cam 38 to the clutch touch point θ f However, the rotational speed of the drive cam 38 in the torque phase can also be made the same as the rotational speed of the drive cam 38 when moving the phase (cam angle) regarding the rotation direction of the drive cam 38 to the clutch touch point θ f or can be made larger than the rotational speed of the drive cam 38 when moving the phase (cam angle) regarding the rotation direction of the drive cam 38 to the clutch touch point θ f In the torque phase, the drive cam 38 is rotationally driven in the direction in which the electric friction clutch device 9 shifts to the connection mode, and the fastening force F

[0222] of the friction engagement portion 29 CBy performing an action to increase the torque T of the input member 6, and simultaneously gradually increasing the output torque of the drive motor 2, the torque T of the input member 6 is increased. in Gradually increase (S3-2).

[0223] In other words, if the torque T of the input member 6 in If the torque is kept constant, the fastening force F of the friction engagement portion 29 during the torque phase. C As the torque increases, the torque passing through the friction engagement portion 29 increases, and therefore the torque T of the output member 7 increases. out The force decreases. Therefore, the fastening force F of the friction engagement portion 29 C Regardless of the increase in the torque T of the output member 7, out The fastening force F of the friction engagement portion 29 is maintained at a nearly constant level. C The torque T of the output member 7 changes according to the amount of increase, i.e., the amount of rotation of the drive cam 38. out Gradually increase it.

[0224] The torque T of the output member 7 is as follows: out Torque T of input member 6 to maintain a nearly constant value in I will explain how to increase it.

[0225] Torque T of input member 6 during the torque phase in and the torque T of the output member 7 out The relationship is as shown in equation (1) below.

number

[0226] Also, the clutch torque capacity T in equation (1) C This can be calculated using equation (2) below.

number

[0227] The control device 4 controls the clutch torque capacity T based on equation (2). C After calculating the torque T of the output member 7, based on the relationship in equation (1), out The torque T of the input member 6 is maintained at approximately a constant value. in Issue a command to increase it.

[0228] In this example, the control device 4 determines the phase (cam angle) of the rotation direction of the drive cam 38 and the fastening force F of the friction engagement part 29, which were obtained by conducting experiments beforehand. C Table T1 shows the relationship, and the fastening force F of the friction engagement part 29. C Using table T2 which shows the relationship between and the coefficient of friction μ, the calculation of equation (2) is performed. Specifically, the control device 4 uses table T1 to calculate the fastening force F of the friction engagement portion 29 with respect to the phase (cam angle) of the rotation direction of the drive cam 38. C Furthermore, using table T2, the fastening force F of the friction engagement portion 29 is determined. C The coefficient of friction μ is determined. Then, the fastening force F of the friction engagement part 29 determined in this way is calculated. C And using the coefficient of friction μ, the clutch torque capacity T is calculated using equation (2). C Calculate.

[0229] However, throughout the entire range of the torque phase, the torque T of the output member 7 is determined based on the relationship in equation (1). out The torque T of the input member 6 is maintained at approximately a constant value. in Issuing a command to increase this may result in the following problems:

[0230] That is, due to factors such as the temperature of the friction engagement portion 29, the wear amount of the axial side surfaces of the first friction plate 33 and the second friction plate 34, and the lubrication state between the axial side surfaces of the first friction plate 33 and the second friction plate 34, the actual friction coefficient μ varies. Therefore, the friction coefficient μ obtained using the table T2 may be larger or smaller than the actual friction coefficient μ. Thus, when the friction coefficient μ is obtained using the table T2, the clutch torque capacity T calculated by equation (2) C may be larger or smaller than the actual clutch torque capacity T C . As a result, the command value of the torque T in of the input member 6 adjusted based on the relationship of equation (1) becomes too large or too small, and when shifting from the torque phase to the inertia phase, the torque T out of the output member 7 fluctuates, and a shift shock may occur.

[0231] Specifically, for example, when the actual friction coefficient μ becomes smaller than expected due to the wear of the axial side surface of the first friction plate 33 and / or the axial side surface of the second friction plate 34, that is, when the assumed friction coefficient μ obtained from the table T2 is larger than the actual friction coefficient μ, the assumed clutch torque capacity T calculated by equation (2) C is larger than the actual clutch torque capacity T C . As a result, as shown in the P portion of FIG. 21, the torque T in of the input member 6 becomes excessive, and accordingly, the torque T out of the output member 7 increases without being maintained substantially constant.

[0232] Incidentally, if an output-side torque sensor for measuring the torque T out of the output member 7 is provided, while monitoring the torque T out of the output member 7 based on the output signal of the output-side torque sensor, the torque T out of the output member 7 is maintained substantially constant, and the torque T inThe command value can be feedback-controlled. However, providing an output-side torque sensor for measuring the torque T of the output member 7 only for such feedback control is not preferable because it causes an increase in cost and / or an increase in the size of the drive device 1 for an electric vehicle. out When the torque T of the input member 6 shown in the P part of FIG. 21 becomes excessive and, accordingly, the torque T of the output member 7 increases without being maintained substantially constant, as a result, as shown in the Q part of FIG. 21, even after shifting from the torque phase to the inertia phase, the torque T of the output member 7 becomes excessive. The reason is as follows.

[0233] As shown in the P part of FIG. 21, when the torque T of the input member 6 in becomes excessive and, accordingly, the torque T of the output member 7 out increases without being maintained substantially constant, as a result, as shown in the Q part of FIG. 21, even after shifting from the torque phase to the inertia phase, the torque T of the output member 7 out becomes excessive. The reason is as follows.

[0234] In the torque phase, when the torque T of the input member 6 in and the torque T of the output member 7 out are equal, the torque phase ends and the process shifts to the inertia phase. In the inertia phase, the torque T of the output member 7 out is not affected by the torque T of the input member 6 in and is secured by the clutch torque capacity T C C and is specifically calculated by the following formula (3).

Equation

[0235] As shown in the P part of FIG. 21, in the torque phase, when the torque T of the input member 6 in becomes excessive and, accordingly, the torque T of the output member 7 out increases without being maintained substantially constant, when the torque T of the input member 6 in and the torque T of the output member 7 out are not equal, the rotation of the drive cam 38 in the direction in which the electric friction clutch device 9 shifts to the connection mode, that is, the direction in which the fastening force F C of the friction engagement part 29 increases progresses, and the actual clutch torque capacity T CThis becomes excessive. Therefore, as shown in section Q of Figure 21, even after transitioning from the torque phase to the inertia phase, the torque T of the output member 7 remains excessive. out This will remain excessive.

[0236] As a result, as shown in sections P and Q of Figure 21, when transitioning from the torque phase to the inertia phase, the torque T of the output member 7 out This can cause fluctuations and potentially lead to shifting shocks.

[0237] On the other hand, if the actual friction coefficient μ is larger than assumed due to factors such as the temperature of the friction engagement part 29 being low in cold regions, that is, if the assumed friction coefficient μ obtained in the table T2 is smaller than the actual friction coefficient μ, then the assumed clutch torque capacity T calculated by equation (2) C The actual clutch torque capacity T C It becomes smaller than that. As a result, as shown in section R of Figure 22, the torque T of the input member 6 in The increase in the torque T of the output member 7 becomes insufficient, and consequently, out It does not remain relatively constant but decreases.

[0238] Furthermore, as shown in section S of Figure 22, even after transitioning from the torque phase to the inertia phase, the torque T of the output member 7 out This remains in an underestimation state. As a result, when transitioning from the torque phase to the inertia phase, the torque T of the output member 7 out This can cause fluctuations and potentially lead to shifting shocks.

[0239] Therefore, in this example, the torque T of the output member 7 out In order to maintain it at a nearly constant level, the torque T of the input member 6 in When increasing (S3-2), if the actual friction coefficient μ becomes larger than expected due to factors such as the temperature of the friction engagement part 29 being low in cold regions, that is, the assumed clutch torque capacity T calculated by equation (2) C The actual clutch torque capacity T CEven if it becomes smaller than (1), the clutch torque capacity T used in the calculation of equation (1) C However, the actual clutch torque capacity T C To prevent it from becoming smaller than this, specifically, the clutch torque capacity T used in the calculation of equation (1) is C The clutch torque capacity T is calculated using equation (2). C It is set to be larger by a predetermined amount ΔT than the specified amount ΔT. The predetermined amount ΔT is not limited to this, but is the clutch torque capacity T calculated by equation (2). C It can be set to approximately 5% to 15%.

[0240] However, it is extremely rare for the actual friction coefficient μ to be larger than expected. Therefore, when implementing this disclosure, the clutch torque capacity T in equation (1) should be used. C The clutch torque capacity T is calculated using equation (2). C It can also be used as is.

[0241] Furthermore, in this example, even if the actual friction coefficient μ becomes smaller than expected due to the wear on the axial side surface of the first friction plate 33 and / or the axial side surface of the second friction plate 34, the torque T of the input member 6 will still be lower. in To prevent it from becoming excessive, the torque T of the input member 6 is increased in the torque phase, as shown in Figure 20. in The target value T set in (S1) is used to determine this. G It is limited to this. For this purpose, in (S4), the torque T of the input member 6 in However, the target value T G A determination is made as to whether or not the torque T of the input member 6 is reached. (S4) in The target value is T G If it is determined that the target has not been reached, the process returns to (S3-1) and (S3-2).

[0242] Thus, in this example, the torque T of the input member 6 is increased during the torque phase. in The target value T set in (S1) is used to determine this. G In order to limit it to a certain point, in the torque phase, the torque T of the input member 6 inThis becomes excessive, and consequently, the torque T of the output member 7 out This prevents the value from increasing instead of being maintained at a constant level. Therefore, it is possible to more reliably prevent shift shock when switching from a high reduction ratio mode to a reduced speed ratio mode.

[0243] In (S4), the torque T of the input member 6 in The target value is T G If it is determined that the torque T of the input member 6 has been reached, then at that point, in The target value T G While holding it in place, the rotation direction of the drive cam 38 is set to the rotation direction in which the electric friction clutch device 9 transitions to the connection mode (the fastening force F of the friction engagement portion 29). C The rotational direction in which the force increases (the direction of rotation) transitions to the cutting mode (the fastening force F of the friction engagement part 29). C Reverses the rotation direction (where the torque decreases). This reduces the clutch torque capacity T C Lower (S5).

[0244] As shown in section P of Figure 21, in the torque phase, the torque T of the input member 6 in This becomes excessive, and consequently, the torque T of the output member 7 out The fact that it does not remain nearly constant but increases means that the phase (cam angle) of the drive cam 38 in relation to the rotation direction changes the fastening force F of the friction engagement portion 29. C This means that the torque T of the input member 6 is moving excessively in the direction of increasing torque. in The target value is T G Even when this is reached, the phase (cam angle) of the drive cam 38 in relation to the rotational direction is the fastening force F of the friction engagement portion 29. C It is moving excessively in the direction of increasing.

[0245] On the other hand, in the inertia phase, the torque T of the output member 7 out The torque T of the input member 6 is in Unaffected by, clutch torque capacity T C This is guaranteed and calculated by equation (3) above. Therefore, in the torque phase, the phase (cam angle) of the drive cam 38 with respect to the rotation direction is the fastening force F of the friction engagement portion 29.C If the torque continues to increase excessively and then transitions to the inertia phase, the torque T of the output member 7 immediately after transitioning to the inertia phase will be out This can become excessive, causing shifting shocks.

[0246] Therefore, in this example, in (S4), the torque T of the input member 6 in The target value is T G If it is determined that the torque T of the input member 6 is reached, in (S5) the torque T of the input member 6 is in The target value T G While holding it in place, the rotation direction of the drive cam 38 is controlled by the fastening force F of the friction engagement portion 29. C From the direction of rotation in which the force increases, the fastening force F of the friction engagement portion 29 C The rotational force is reversed in the direction of decrease. As a result, the phase (cam angle) of the drive cam 38 with respect to the rotational direction changes, and the fastening force F of the friction engagement portion 29 is reversed. C This prevents the transition from the torque phase to the inertia phase while the torque T of the output member 7 remains excessively advanced in the direction of increasing torque. In other words, it prevents the transition from the torque T of the output member 7 at the end of the torque phase. out The target value T G By matching this, the torque T of the output member 7 immediately after transitioning to the inertia phase is out This prevents the value from becoming excessive and thus prevents shift shock. Therefore, in this example, in this respect as well, it is possible to more reliably prevent shift shock when switching from high reduction ratio mode to low reduction ratio mode.

[0247] During the torque phase, the torque T of the input member 6 in and the torque T of the output member 7 out When these conditions are met, the torque phase ends and the inertia phase begins. When the inertia phase begins, the rotational speed of the motor output shaft 5 of the drive motor 2 decreases, that is, the rotational speed R of the input member 6 decreases. in It begins to decrease.

[0248] Therefore, in this example, after the start of operation (S5), in (S6), the rotational speed R of the input member 6 is determined based on the output signal of the input-side rotation sensor.in The rotational speed R of the input member 6 is monitored. in The system determines whether the decrease in R has reached a predetermined amount ε. Then, it checks the rotational speed R of the input member 6. in If it is determined that the decrease has not reached a predetermined amount ε, the process returns to (S5). The predetermined amount ε in this case is not limited to this, but for example, 10 min -1 ~15min -1 It is preferable to set it to this value. However, if the set value of the predetermined amount ε is set too large, the cam angle will return too far and the clutch torque capacity T will be reduced. C When the torque drops excessively, the rotational speed R of the input member 6 decreases. in The value then starts to increase. Therefore, it is desirable to set the predetermined value ε to a value that does not cause such problems, based on prior experiments or other assessments.

[0249] In (S6), the rotational speed R of the input member 6 in When it is determined that the decrease in the torque has reached a predetermined amount ε, that is, when it is determined that the torque phase has ended, at that point, that is, at the start of the inertia phase, the rotation direction of the drive cam 38 is changed to the rotation direction in which the electric friction clutch device 9 transitions to the engagement mode (the fastening force F of the friction engagement portion 29). C (In the direction in which it increases), and the phase (cam angle) of the rotation direction of the drive cam 38 is returned to the torque T of the output member 7. out The rotational speed R of the input member 6 is changed so that it does not fluctuate (S7-1), and the rotational speed R of the input member 6 is changed. in and the rotational speed R of the output member 7 out The torque T of the input member 6 is set to match. in Adjust (S7-2).

[0250] The friction coefficient μ between the first friction plate 33 and the second friction plate 34 also fluctuates depending on the difference in rotational speed (difference rotation) between the first friction plate 33 and the second friction plate 34. Therefore, in this example, in (S7-1), the μ-V characteristic, which represents the relationship between the friction coefficient μ between the first friction plate 33 and the second friction plate 34 and the difference rotation between the first friction plate 33 and the second friction plate 34, obtained experimentally in advance, is used to determine the phase (cam angle) of the rotation direction of the drive cam 38, and the torque T of the output member 7. out Control is implemented to prevent fluctuations.

[0251] Specifically, in (S7-1), the "μ change Δμ" calculated by "friction coefficient μ at the current differential rotation" / "friction coefficient μ at the differential rotation at the start of the torque phase" is considered, and the necessary "fastening force F of the friction engagement part 29" is determined. C The rate of change of "μ change amount Δμ" is calculated. Also, "clutch torque capacity T at the start of the torque phase" × "μ change amount Δμ" × "clutch torque capacity T at the start of the torque phase". C The "target cam angle" corresponding to the "target clutch torque capacity" calculated in the map M C This is determined using the following method. Then, the phase (cam angle) of the drive cam 38 in relation to the rotation direction is calculated as described above, and the fastening force F of the friction engagement part 29 is used. C The control is performed to change the rotational speed R of the input member 6 toward the "target cam angle" determined as described above, at a rotational speed that can achieve the "rate of change" of R. in and the rotational speed R of the output member 7 out The phase (cam angle) of the drive cam 38 with respect to the direction of rotation can also be changed linearly over time until the two conditions coincide. Furthermore, if the variation in the friction coefficient μ with respect to the differential rotation is small enough to be negligible, the phase (cam angle) of the drive cam 38 with respect to the direction of rotation can also be changed without considering the variation in the friction coefficient μ with respect to the differential rotation.

[0252] In (S7-2), after the start of the inertia phase, the torque T of the input member 6 in The rotation speed R of the input member 6 is temporarily reduced. in This promotes a further reduction of the torque T of the input member 6. inThe amount of decrease is the rotational speed R of the input member 6. in It is not particularly limited as long as it can encourage a further decrease in [the number of cases].

[0253] Rotational speed R of input member 6 in When the decrease in torque T of input member 6 begins to accelerate, in The target value is T G Until it returns, the torque T of input member 6 in This increases the torque T of the input member 6. in The rate of increase is such that by the end of the inertia phase, the torque T of the input member 6 in The target value T G As long as it can be restored to that point, it is not particularly limited.

[0254] In this example, the rotational speed R of the input member 6 is measured by the input-side rotation sensor. in The rotational speed R of the output member 7 is measured by the output side rotation sensor. out While monitoring the rotation speed R of the input member 6, in and the rotational speed R of the output member 7 out The torque T of the input member 6 is set to match. in Feedback control is performed to adjust the torque T of the input member 6. in Based on the adjustment of the rotation speed R of the input member 6, in Adjust.

[0255] In short, in (S7-2), the rotational speed R of the input member 6 in The rotational speed R of the input member 6 decreases. in and the rotational speed R of the output member 7 out As the difference ΔR decreases, the torque T of the input member 6, which was initially reduced, in The torque T of the input member 6 is increased, and when the difference ΔR becomes 0, in The target value is T G Control it so that it becomes like this.

[0256] Next, in (S8), the rotational speed R of the input member 6 in and the rotational speed R of the output member 7out It determines whether the two values ​​match, that is, whether the difference ΔR is below a predetermined threshold.

[0257] Rotational speed R of input member 6 in and the rotational speed R of the output member 7 out If it is not determined that they match, return to (S7-1) and (S7-2).

[0258] Rotational speed R of input member 6 in and the rotational speed R of the output member 7 out If it is determined that the two conditions match, the inertia phase is considered to have ended, and the process proceeds to the next step (S9).

[0259] In (S9), the electric actuator 32 rotates the drive cam 38 to a predetermined phase in the circumferential direction, positioning the rolling element 40 on the first bottom 52a of the drive cam surface 52, and displacing the driven cam 39 toward the other axial direction, which reduces the axial distance between it and the drive cam 38. This reduces the piston clearance C between the axial end of the pressing member 62 and the other axial side of the piston 36. p Ensure that. In other words, piston clearance C p Make it greater than or equal to 0, preferably greater than 0.

[0260] Piston clearance C p After securing the necessary items, proceed to the end.

[0261] As a result, the two-speed transmission 3 is switched from high reduction ratio mode to reduced speed ratio mode. Thereafter, the two-speed transmission 3 is maintained in reduced speed ratio mode by maintaining the phase of the drive cam 38 in the circumferential direction.

[0262] 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 reliably prevent shift shock when switching from the high reduction ratio mode to the reduced speed ratio mode.

[0263] Additionally, the two-speed transmission 3 may have a neutral mode in which torque is not transmitted between the input member 6 and the output member 7. To switch the two-speed transmission 3 to neutral mode, the electric friction clutch device 9 is switched to the disengagement mode, and the rotation transmission state switching device 10 is switched to the free mode. In neutral mode, the input member 6 and the output member 7 rotate freely relative to each other, and torque is not transmitted between the input member 6 and the output member 7.

[0264] Additionally or alternatively, the two-speed transmission 3 may have a parking lock mode that locks the rotation of the output member 7. To switch the two-speed transmission 3 to parking lock mode, the electric friction clutch device 9 is switched to connection mode, and the rotation transmission state switching device 10 is switched to lock mode. In parking lock mode, the rotation of the input member 6 and the output member 7 is locked.

[0265] [Example 2] A second example of the embodiment of this disclosure will be described with reference to Figures 25 to 27. In the electric vehicle drive system 1a of this example, the structure of the two-speed transmission 3a differs from the structure of the two-speed transmission 3 of the first example.

[0266] In this example, the two-speed transmission 3a comprises an input member 6a, an output member 7a, a rotating member 8a, an electric friction clutch device 9a, a rotation transmission state switching device 10a, and a planetary gear mechanism 11a.

[0267] In this example, the electric friction clutch device 9a is provided between the rotating member 8a and the input member 6a, and switches between a connection mode in which torque is transmitted between the rotating member 8a and the input member 6a, and a disconnection mode in which torque is not transmitted. That is, in this example, the second clutch member 28a rotates integrally with the input member 6a. More specifically, the second clutch member 28a is made up of the input member 6a itself. Also, the first clutch member 27a is made up of the rotating member 8a itself.

[0268] In this example, the electric friction clutch device 9a is positioned between the friction engagement portion 29 and the driven cam 39 of the cam device 31, and includes an elastic biasing mechanism 30a that elastically biases the friction engagement portion 29 and the driven cam 39 in a direction away from each other.

[0269] The elastic biasing mechanism 30a has an elastic member 37a and a thrust bearing 61a between the friction engagement portion 29 and the driven cam 39, in that order from the side of the driven cam 39.

[0270] The elastic member 37a is composed of a single disc spring.

[0271] The thrust bearing 61a has a pair of raceway rings 63c and 63d, and a plurality of rolling elements 64 that are rotatably arranged between the pair of raceway rings 63c and 63d.

[0272] In this example, when switching the electric friction clutch device 9a to a disengagement mode in which torque is not transmitted between the rotating member 8a and the input member 6a, the electric actuator 32 rotates the drive cam 38, causing the driven cam 39 to move in a direction that reduces the axial distance between it and the drive cam 38. As a result, the force pressing the first friction plate 33 and the second friction plate 34 against each other is lost. Consequently, the return spring 35 causes the distance between the first friction plate 33 and the second friction plate 34 to widen, the friction engagement portion 29 is disengaged, and the electric friction clutch device 9a switches to the disengagement mode.

[0273] In contrast, when switching the electric friction clutch device 9a to a connection mode in which torque is transmitted between the rotating member 8a and the input member 6a, the electric actuator 32 rotates the drive cam 38, moving the driven cam 39 in a direction that increases the axial distance between it and the drive cam 38. As a result, the driven cam 39 presses the first friction plate 33 and the second friction plate 34 against each other via the elastic member 37a and the thrust bearing 61a. Consequently, the first friction plate 33 and the second friction plate 34 press against each other, and the friction engagement portion 29a is connected, thereby switching the electric friction clutch device 9a to connection mode.

[0274] In this example, when the electric friction clutch device 9a is maintained in the connected mode, the shift motor 70 must be continuously energized. Conversely, when the electric friction clutch device 9a is maintained in the disconnected mode, it is not necessary to continuously energize the shift motor 70. In other words, the electric friction clutch device 9a in this example is configured as a normally open type clutch device.

[0275] In this example, the planetary gear mechanism 11a is composed of a single-pinion type planetary gear mechanism. In this example, the carrier 106a is connected to the output member 7a so as to rotate integrally with the output member 7a, the sun gear 104a is connected to the input member 6a so as to rotate integrally with the input member 6a, and the ring gear 105a is connected to the rotating member 8a so as to rotate integrally with the rotating member 8a.

[0276] In the electric vehicle drive system 1a of this example, the control device 4 is equipped with 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 6a and the output member 7a is large, and a low reduction ratio mode in which the reduction ratio is small.

[0277] <Reduced Speed ​​Ratio Mode> To switch the two-speed transmission 3a to the reduced gear ratio mode, the electric friction clutch device 9a is switched to the connected mode. This causes the input member 6a and the rotating member 8a to rotate together, and the sun gear 104a and the ring gear 105a to rotate together. In addition, the rotation transmission state switching device 10a is switched to the free mode. This allows the rotation of the rotating member 8a relative to the fixed part 12, and allows the rotation of the ring gear 105a.

[0278] In the reduced speed ratio mode, the rotation direction and rotation speed of the sun gear 104a, ring gear 105a, and carrier 106a become the same, and the entire planetary gear mechanism 11a rotates as a single unit, in a so-called glued state. Therefore, the torque of the input member 6a is transmitted in the order of input member 6a, carrier 106a, and output member 7a, as shown by the thick line in Figure 26(A), and is taken out from the output member 7.

[0279] <High reduction ratio mode> To switch the two-speed transmission 3a to the reduced gear ratio mode, the electric friction clutch device 9a is switched to the disengagement mode. This allows the input member 6a and the rotating member 8a to rotate relative to each other, and the sun gear 104a and the ring gear 105a to rotate relative to each other. In addition, the rotation transmission state switching device 10a is switched to the lock mode. This prevents the rotation of the rotating member 8a relative to the fixed part 12, and prevents the rotation of the ring gear 105a.

[0280] In high reduction ratio mode, the torque of the input member 6a is transmitted in the following order, as shown in Figure 26(B): input member 6a, sun gear 104a, rotational motion of planetary gear 107a, revolutionary motion of planetary gear 107a based on meshing with ring gear 105a, carrier 106a, and output member 7a, and is extracted from output member 7a.

[0281] In this example as well, the two-speed transmission 3a passes through a reduction ratio switching mode during the transition from the high reduction ratio mode to the reduced speed ratio mode while driving forward under normal conditions.

[0282] In this example as well, the control device 4, during the torque phase while the reduction ratio switching mode is being executed, controls the torque T of the input member 6a at the start of the reduction ratio switching mode. in Value (reference value) T B The value T is obtained by multiplying this by the reduction ratio i in high reduction ratio mode. G With this as the target value, the torque T of the input member 6a in Control is implemented to increase the value. Therefore, as in the first example, the shift shock when switching from the high reduction ratio mode to the reduced speed ratio mode can be prevented more reliably.

[0283] In this example as well, the control device 4 controls the torque T of the input member 6a during the torque phase while the reduction ratio switching mode is being executed. in The target value is T G When it reaches this point, the torque T of the input member 6a in The target value T G While maintaining this position, the rotation direction of the drive cam 38 is reversed from the rotation direction in which the electric friction clutch device 9a transitions to the engagement mode to the rotation direction in which it transitions to the disengagement mode. Then, when the rotational speed of the input member 6a decreases by a predetermined amount, the rotation direction of the drive cam 38 is controlled to return to the rotation direction in which the electric friction clutch device 9a transitions to the engagement mode. Therefore, in this respect as well, similar to the first example, the shift shock when switching from the high reduction ratio mode to the reduced speed ratio mode can be prevented more reliably.

[0284] The composition and effects of the other parts of the second example are the same as those of the first example. [Explanation of symbols]

[0285] 1, 1a Drive system for electric vehicles 2 Drive motor 3, 3a 2-speed transmission 4. Control device 5. Motor output shaft 6, 6a Input members 7, 7a Output component 8, 8a Rotating member 9, 9a Electric friction clutch device 10, 10a Rotation transmission state switching device 11, 11a Planetary gear mechanism 12 Fixed part 13 Drive gear 14 Input Gears 15 Output Gear 16 Small diameter flange section 17 Flange section 18 Through hole 19 1st circular limbus 20 First cylindrical section 21 Second circular ring 22 Second cylindrical section 23 Shaft member 24-step cylindrical member 25 Small diameter cylindrical section 26 Female spline section 27, 27a First clutch member 28, 28a Second clutch member 29 Friction engagement part 30, 30a Elastic biasing mechanism 31, 31z cam mechanism 32 Electric Actuators 33 1st friction plate 34 2nd friction plate 35 Return Spring 36 pistons 37, 37a Elastic members 38, 38z drive cam 39 Driven cam 40 Rolling element 41 Cylindrical member 42 Radial bearings 43 Angular Contact Ball Bearings 44 Cylindrical section 45 Outward flange section 46 Inner circle 47 Outer ring 48 Rolling element 49 Inner circle 50 Outer ring 51 balls 52 Drive cam surface 52a 1st bottom 52b Gentle slope section 52c 1st flat surface part 52d Slope section 52e 2nd bottom 52f 1st medium slope section 52g 2nd flat surface part 52h 2nd medium slope section 53 Wheel Teeth 54 Pin section 55 Female spline section 56 Male spline section 57 Rectangular hole 58a, 58b Support plate part 59 Support hole 60 Support recess 61, 61a Thrust bearing 62 Pressing member 63a, 63b, 63c, 63d bearing ring 64 Rolling element 65 Preload applying means 66 base 67 Partial cylindrical section 68 Support shaft Around 69 70 Shift motor 71 Reducer 72 Warm 73a, 73b Support bearings 74 First Member 75 Second Member 76 Mode Select Components 77 Engaging recess 78 Convex part 79 Uneven part 80 Outer diameter side uneven engagement part 81 Inner diameter side uneven engagement part 82 Inner diameter side uneven engagement part 83 Base 84 Cylindrical section 85 First retaining recess 86 Second retaining recess 87a, 87b Spring retaining part 88a, 88b Base 89 1st claw member 90 Second claw member 91 First claw biasing member 92 Second claw biasing member 93 1st base 94 First Engaging Claw 95 Annular protrusion 96 Second base 97 Second Engaging Claw 98 Base 99 Plate-side engagement holes 100 Protrusion 101 Uneven part 102 Lid 103 Retaining ring 104, 104a Sun Gear 105, 105a Ring gear 106, 106a carrier 107 Planetary Gear 108 drive wheels 109 Torque transmission mechanism 110 Ring Gear 201 First friction engagement device 202 Second friction engagement device 203 First driven cam 204 Second driven cam

Claims

1. A drive motor having a motor output shaft, A two-speed transmission having an input member capable of transmitting torque to the motor output shaft, an output member supported to enable relative rotation with respect to the input member, a rotating member supported to enable relative rotation with respect to the input member and the output member, an electric friction clutch device, and a rotation transmission state switching device, Control device and Equipped with, The aforementioned electric friction clutch device, A first clutch member that rotates integrally with the rotating member, or is formed by the rotating member itself, A second clutch member is supported coaxially with the first clutch member, enabling relative rotation with respect to the first clutch member, and rotating integrally with the input member or the output member, or is composed of the input member or the output member itself. A friction engagement portion is provided between the first clutch member and the second clutch member, having at least one first friction plate and at least one second friction plate, which are supported to allow relative axial displacement, A cam device comprising a drive cam and a driven cam supported to allow relative rotation and relative axial displacement with respect to the drive cam, wherein the axial distance between the drive cam and the driven cam expands and contracts as the drive cam rotates, It has a shift motor and a reduction gear, and an electric actuator that rotates the drive cam via the reduction gear using the shift motor, and, The cam mechanism 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 or contracting the axial dimension of the cam mechanism, and a disconnection mode, in which torque is not transmitted between the first clutch member and the second clutch member by releasing the force pressing the at least one first friction plate and the at least one second friction plate against each other. The rotation transmission state switching device is A first member having multiple engagement recesses in the circumferential direction, A second member arranged coaxially with the first member, A mode select member having multiple protrusions that project radially or axially in the circumferential direction, which rotates or is displaced axially in conjunction with the rotation of the drive cam, A first claw member having a first base pivotally supported on the second member, and a first engaging claw extending from the first base toward the first side in the circumferential direction, A second claw member having a second base pivotally supported on the second member, and a second engaging claw extending from the second base toward the second side in the circumferential direction, A first claw biasing member elastically biases the first engaging claw in a direction that engages it with the engaging recess, The device comprises a second claw biasing member that elastically biases the second engaging claw in a direction that engages it with the engaging recess, One of the first member and the second member rotates integrally with the rotating member, or is composed of the rotating member itself, and the other of the first member and the second member is supported so as not to rotate relative to a fixed portion that does not rotate even during use. The device is configured to be switchable between a lock mode, in which the protrusion is positioned circumferentially or axially away from the first and second engaging claws, and the first and second engaging claws are engaged in the engagement recess, thereby preventing the rotation of one member relative to the other member regardless of the relative rotation direction of the one member relative to the other member; a free mode, in which the first and second engaging claws are pressed radially or axially by the protrusion and retracted from the engagement recess, thereby allowing the rotation of one member relative to the other member regardless of the relative rotation direction of the one member relative to the other member; and a one-way clutch mode, in which only one of the first and second engaging claws is pressed radially or axially by the protrusion and retracted from the engagement recess, and the other engaging claw is engaged in the engagement recess, thereby allowing the one member to rotate in a predetermined direction relative to the other member, and preventing the one member from rotating in the opposite direction relative to the other member. The control device is Based on the rotational drive of the drive cam by the electric actuator, the two-speed transmission is switched to a high reduction ratio mode, where the reduction ratio between the input member and the output member is large, by switching the electric friction clutch device to the disconnection mode and the rotation transmission state switching device to the lock mode, and the two-speed transmission is switched to a low reduction ratio mode, where the reduction ratio between the input member and the output member is small, by switching the electric friction clutch device to the connection mode and the rotation transmission state switching device to the free mode, the two-speed transmission is provided with a reduction ratio switching function. When the reduction ratio switching function switches the two-speed transmission from the high reduction ratio mode to the reduced speed ratio mode, the rotational transmission state switching device is switched to the one-way clutch mode at the same time as, or after, the reduction ratio switching mode is activated to increase the fastening force of the friction engagement portion of the electric friction clutch device. During the torque phase in the execution of the reduction ratio switching mode, control is performed to increase the torque of the input member, with the value obtained by multiplying the torque value of the input member at the start of the reduction ratio switching mode by the reduction ratio in the high reduction ratio mode as the target value. A drive system for electric vehicles.

2. The control device, in the torque phase, when the torque of the input member reaches the target value, maintains the torque of the input member at the target value while reversing the rotation direction of the drive cam from the rotation direction in which the electric friction clutch device transitions to the connection mode to the rotation direction in which it transitions to the disconnection mode, and then, when the rotation speed of the input member decreases by a predetermined amount, controls the rotation direction of the drive cam back to the rotation direction in which the electric friction clutch device transitions to the connection mode, as described in claim 1.

3. The system further comprises an input-side rotation sensor for measuring the rotational speed of the input member and an output-side rotation sensor for measuring the rotational speed of the output member, The control device, during the inertia phase while the reduction ratio switching mode is being executed, uses a μ-V characteristic representing the relationship between the friction coefficient between the first friction plate and the second friction plate and the difference in rotational speed between the first friction plate and the second friction plate to control the phase of the drive cam with respect to the rotational direction so that the torque of the output member does not fluctuate, and while monitoring the rotational speed of the input member measured by the input-side rotation sensor and the rotational speed of the output member measured by the output-side rotation sensor, controls the torque of the input member so that the rotational speed of the input member and the rotational speed of the output member match. The drive system for an electric vehicle according to claim 1.

4. The electric friction clutch device has a return spring that elastically biases the at least one first friction plate and the at least one second friction plate in a direction that separates them from each other, according to claim 1, for use as an electric vehicle drive device.

5. The electric friction clutch device further comprises an elastic biasing mechanism provided between the first clutch member or the second clutch member and the friction engagement portion, which elastically biases the at least one first friction plate and the at least one second friction plate in a direction that causes them to press against each other, according to claim 1.

6. The electric friction clutch device further comprises an elastic biasing mechanism disposed between the friction engagement portion and the driven cam, which elastically biases the friction engagement portion and the driven cam in a direction away from each other, according to claim 1.

7. The aforementioned two-speed transmission further comprises a planetary gear mechanism having a sun gear, a ring gear arranged coaxially with the sun gear around the sun gear, a carrier supported to enable relative rotation between the sun gear and the ring gear, and a plurality of planetary gears that mesh with the sun gear and the ring gear and are supported on the carrier to enable rotation about their own central axis. The input element, which is one of the sun gear, the ring gear, and the carrier, rotates integrally with the input member, or is composed of the input member itself. An output element, which is one of the sun gear, the ring gear, and the carrier and is a separate element from the input element, rotates integrally with the output member, or is composed of the output member itself. The rotating elements, which are the remaining elements of the sun gear, ring gear, and carrier excluding the input element and the output element, rotate integrally with the rotating member, or are composed of the rotating member itself. The drive system for an electric vehicle according to claim 1.

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