Vehicle drive device

Abstract

This vehicle drive device comprises: a rotating electric machine having a cylindrical rotor shaft connected so as to rotate integrally with a rotor; a drive transmission mechanism provided in a power transmission path connecting the rotor shaft and a wheel and having an input shaft coupled to the rotor shaft; and a housing for housing the rotating electric machine and the drive transmission mechanism. The rotor shaft is supported to the housing via a first ball bearing having a first inner ring and a first outer ring. The input shaft is supported to the housing via a second ball bearing having a second inner ring and a second outer ring. An elastic member is disposed between the first ball bearing and the second ball bearing which are adjacent to each other in the axial direction of the rotor shaft and the input shaft, the elastic member pressing the first ball bearing and the second ball bearing in a direction for separating the bearings from each other.

Description

Vehicle drive unit

[0001] The present invention relates to a vehicle drive system including a rotating electric machine that serves as a drive source for wheels, and a drive transmission mechanism provided in a power transmission path that connects the rotating electric machine to the wheels.

[0002] An example of such a vehicle drive device is disclosed in the following Patent Document 1. In the following description of this background art, reference numerals in Patent Document 1 will be quoted in parentheses.

[0003] The vehicle drive device (1) of Patent Document 1 includes a rotor shaft (60) of a rotating electric machine (M) and an input shaft (10) spline-connected to the rotor shaft (60), and is provided with a wave spring (82) that presses the rotor shaft (60) and the input shaft (10) in directions away from each other in the axial direction.

[0004] Japanese Patent Application Laid-Open No. 2005-28907

[0005] In the vehicle drive device (1) of Patent Document 1, a wave spring (82) presses a rotor shaft (60) against a housing (5), and reduces radiated noise generated in the housing (5) by transmitting vibrations of a rotating electric machine (M).

[0006] On the other hand, since the rotational noise of the rotating electric machine (M) is generated by a number of factors, such as the accuracy of the spline connection and the amount of radial play during rotation, it is difficult to reduce the rotational noise by simply pressing the rotor shaft (60) against the housing (5).

[0007] Therefore, it is desirable to realize a vehicle drive device that can effectively suppress the rotation noise of a rotating electric machine.

[0008] In view of the above, a characteristic configuration of a vehicle drive device is provided with: a rotating electric machine having a stator, a rotor rotatably supported relative to the stator, and a cylindrical rotor shaft connected to rotate integrally with the rotor, and serving as a drive source for wheels; a drive transmission mechanism provided in a power transmission path connecting the rotor shaft and the wheels and having an input shaft connected to the rotor shaft; and a housing that accommodates the rotating electric machine and the drive transmission mechanism, wherein the rotor shaft is supported by the housing via a first ball bearing having a first inner ring and a first outer ring, and the input shaft is supported by the housing via a second ball bearing having a second inner ring and a second outer ring, and an elastic member is arranged between the first ball bearing and the second ball bearing, which are adjacent to each other in the axial direction of the rotor shaft and the input shaft, to bias the first ball bearing and the second ball bearing in a direction separating them.

[0009] According to this characteristic configuration, an elastic member is disposed between the first ball bearing of the rotor shaft and the second ball bearing of the input shaft, biasing the first ball bearing and the second ball bearing in a direction separating them. For example, if the inner ring of the first ball bearing is movable relative to the rotor shaft, the biasing force of the elastic member causes the first inner ring and the first outer ring to abut against the balls. As a result, under normal conditions, the amount of radial rattle is reduced, achieving smooth rotation of the rotating electric machine. In addition, when excessive force is applied, a force counteracting the biasing force of the elastic member causes the first inner ring and the first outer ring to separate from the balls, preventing seizure of the first ball bearing. Furthermore, because the biasing force of the elastic member moves the first ball bearing toward the rotor shaft, rattle of the first ball bearing on the rotor shaft is also suppressed. Furthermore, because the elastic member is disposed between the first ball bearing and the second ball bearing that are adjacent to each other in the axial direction of the rotor shaft and the input shaft, i.e., for example, near the spline connection between the two shafts, machining errors in the spline connection can be absorbed.

[0010] Therefore, the vehicle drive device can effectively suppress the rotation noise of the rotating electric machine.

[0011] 3 is a cross-sectional view along the axial direction of the vehicle drive device according to the first embodiment. FIG. 4 is a skeleton diagram of the vehicle drive device according to the first embodiment. FIG. 5 is a diagram showing the positional relationship of each element in the vehicle drive device according to the first embodiment when viewed from the front. FIG. 6 is a diagram showing the positional relationship of each element in the vehicle drive device according to the first embodiment when viewed in the axial direction. FIG. 7 is a cross-sectional view taken along the V-V arrows in FIG. 3. FIG. 8 is a cross-sectional view taken along the VI-VI arrows in FIG. 3. FIG. 9 is a cross-sectional view of a main part of a first case. FIG. 10 is a front view of the vehicle drive device according to the first embodiment. FIG. 11 is a side view of one side of the vehicle drive device according to the first embodiment. FIG. 12 is a side view of the other side of the vehicle drive device according to the first embodiment. FIG. 13 is a diagram showing an example of a vehicle in which the vehicle drive device is arranged. FIG. 14 is a cross-sectional view of a main part of the vehicle drive device according to the first embodiment. FIG. 15 is a cross-sectional view of a main part of the vehicle drive device according to the second embodiment. FIG. 16 is a cross-sectional view of a main part of the vehicle drive device according to the third embodiment. FIG. 17 is a cross-sectional view of a main part of the vehicle drive device according to the fourth embodiment. FIG. 18 is a front view of a vehicle drive device according to another embodiment.

[0012] Hereinafter, an embodiment of a vehicle drive device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit and scope of the present invention.

[0013] 1 and 2 , a vehicle drive device 100 includes a rotating electric machine 1 including a stator 11 and a rotor 12, an input member 2, a pair of output members 3, a differential gear mechanism 4, and an inverter device 10. In this embodiment, the vehicle drive device 100 further includes a counter gear mechanism 5 and a case 9.

[0014] The rotating electric machine 1 is disposed on a first axis X1. The first axis X1 is the rotational axis of the rotor 12. In this embodiment, the input member 2 is also disposed on the first axis X1. The differential gear mechanism 4 is disposed on a second axis X2 different from the first axis X1. In this embodiment, the pair of output members 3 are also disposed on the second axis X2. Furthermore, in this embodiment, the counter gear mechanism 5 is disposed on a third axis X3 different from the first axis X1 and the second axis X2. In this example, the axes X1 to X3 are disposed parallel to one another.

[0015] In the following description, the direction parallel to the above-mentioned axes X1 to X3 will be referred to as the "axial direction L" of the vehicle drive device 100. One side of the axial direction L will be referred to as the "first axial side L1," and the other side of the axial direction L will be referred to as the "second axial side L2." In this embodiment, in the axial direction L, the side on which the rotating electric machine 1 is disposed relative to the input member 2 will be referred to as the first axial side L1, and the opposite side will be referred to as the second axial side L2. Furthermore, the direction orthogonal to each of the above-mentioned axes X1 to X3 will be referred to as the "radial direction R" based on each axis. Note that when it is not necessary to distinguish which axis is used as the reference or when it is clear which axis is used as the reference, the term "radial direction R" may be used simply.

[0016] 1 , the case 9 houses the rotating electric machine 1, the input member 2, the differential gear mechanism 4, and the inverter device 10. In this embodiment, the case 9 also houses a pair of output members 3 and a counter gear mechanism 5. The pair of output members 3 are housed in the case 9 with portions of them exposed to the outside of the case 9.

[0017] A first housing section A1, a second housing section A2, a third housing section A3, and a fourth housing section A4 are formed inside the case 9. In this embodiment, the first housing section A1 is a space that houses the rotating electric machine 1. The second housing section A2 is a space that houses the input member 2, the counter gear mechanism 5, and the parking mechanism 7. The third housing section A3 is a space that houses the pair of output members 3 and the differential gear mechanism 4. The fourth housing section A4 is a space that houses the inverter device 10.

[0018] In this embodiment, the case 9 includes a partition portion 91, a first peripheral wall portion 92a, a first side wall portion 92b, a second peripheral wall portion 93a, a second side wall portion 93b, a third peripheral wall portion 94a, a third side wall portion 94b, a fourth side wall portion 94c, a storage wall portion 95a, and a lid portion 95b.

[0019] The partition wall 91 is formed to separate the first housing portion A1 and the second housing portion A2. In this embodiment, the partition wall 91 is formed to extend along the radial direction R. In other words, the partition wall 91 separates the first housing portion A1 and the second housing portion A2 in the axial direction L.

[0020] The first circumferential wall portion 92a is formed to cover the outer side of the rotating electric machine 1 in the radial direction R. The first side wall portion 92b is formed to cover the first axial side L1 of the rotating electric machine 1. In this embodiment, the first circumferential wall portion 92a is formed in a cylindrical shape with an opening on the first axial side L1. The opening on the first axial side L1 of the first circumferential wall portion 92a is closed by the first side wall portion 92b. Meanwhile, a partition wall portion 91 is integrally formed on the first circumferential wall portion 92a on the second axial side L2 with respect to the rotating electric machine 1. In this example, the partition wall portion 91, the first circumferential wall portion 92a, the third circumferential wall portion 94a, the third side wall portion 94b, and the housing wall portion 95a are integrally formed to constitute a first case portion 9A. A second case portion 9B including the first side wall portion 92b is joined to the first case portion 9A from the first axial side L1.

[0021] The second peripheral wall portion 93a is formed to cover the outside of the input member 2 and the counter gear mechanism 5 in the radial direction R. The second side wall portion 93b is formed to cover the second axial side L2 of the input member 2 and the counter gear mechanism 5. In this embodiment, the second side wall portion 93b is integrally formed on the second peripheral wall portion 93a at the second axial side L2 relative to the input member 2 and the counter gear mechanism 5. In this example, the second peripheral wall portion 93a, the second side wall portion 93b, and the fourth side wall portion 94c are integrally formed to form a third case portion 9C. The third case portion 9C is joined to the first case portion 9A from the second axial side L2. As a result, the opening of the second peripheral wall portion 93a on the first axial side L1 is blocked by the first case portion 9A (partition wall portion 91).

[0022] The third peripheral wall portion 94a is formed to cover the outer sides of the pair of output members 3 and the differential gear mechanism 4 in the radial direction R. The third side wall portion 94b is formed to cover the first axial side L1 of the differential gear mechanism 4. The fourth side wall portion 94c is formed to cover the second axial side L2 of the differential gear mechanism 4. In this embodiment, the third peripheral wall portion 94a and the third side wall portion 94b are both formed integrally with the first case portion 9A. The opening of the third peripheral wall portion 94a on the second axial side L2 is closed by the fourth side wall portion 94c. As described above, the fourth side wall portion 94c is formed integrally with the second peripheral wall portion 93a and the second side wall portion 93b.

[0023] In this embodiment, the first storage section A1 is formed by the partition wall 91, the first peripheral wall 92a, and the first side wall 92b. That is, the space inside the case 9 surrounded by the partition wall 91, the first peripheral wall 92a, and the first side wall 92b forms the first storage section A1.

[0024] In this embodiment, the second storage section A2 is formed by the partition wall 91, the second peripheral wall 93a, and the second side wall 93b. That is, the space enclosed by the partition wall 91, the second peripheral wall 93a, and the second side wall 93b inside the case 9 is formed as the second storage section A2. In this embodiment, the third storage section A3 is formed by the third peripheral wall 94a, the third side wall 94b, and the fourth side wall 94c. That is, the space enclosed by the third peripheral wall 94a, the third side wall 94b, and the fourth side wall 94c inside the case 9 is formed as the third storage section A3. In this embodiment, the second storage section A2 and the third storage section A3 are formed to be in communication with each other.

[0025] In this embodiment, the fourth storage section A4 is formed by the storage wall 95 a and the lid 95 b. That is, the space inside the case 9 surrounded by the storage wall 95 a and the lid 95 b forms the fourth storage section A4.

[0026] The accommodation wall portion 95a is formed in a cylindrical shape that surrounds the side of the inverter device 10. In the present embodiment, the accommodation wall portion 95a extends upward from the first peripheral wall portion 92a and the second peripheral wall portion 93a in a vehicle-mounted state so as to form an opening for inserting and removing the inverter device 10 into and from the fourth accommodation portion A4. Here, the "vehicle-mounted state" refers to a state in which the vehicle drive device 100 is mounted on a vehicle. As described above, the accommodation wall portion 95a is formed integrally with the partition wall portion 91, the first peripheral wall portion 92a, the third peripheral wall portion 94a, and the third side wall portion 94b.

[0027] The lid portion 95b is formed to close the opening in the storage wall portion 95a. In this embodiment, the lid portion 95b is configured to be detachable from the storage wall portion 95a.

[0028] The rotating electric machine 1 functions as a drive source for the wheels WH (see FIG. 2 ). The rotating electric machine 1 has a function as a motor (electric motor) that receives a supply of electric power to generate power, and a function as a generator that receives a supply of power to generate electric power. Specifically, the rotating electric machine 1 is electrically connected to an electric storage device (not shown), such as a battery or a capacitor. The rotating electric machine 1 generates driving force by running using electric power stored in the electric storage device. The rotating electric machine 1 also generates power using driving force transmitted from the wheels WH to charge the electric storage device.

[0029] As shown in FIG. 1 , the stator 11 of the rotating electric machine 1 includes a cylindrical stator core 111. The stator core 111 is fixed to a non-rotating member. In this embodiment, the stator core 111 is fixed to a first peripheral wall portion 92a of the case 9, which serves as a non-rotating member. The rotor 12 of the rotating electric machine 1 includes a cylindrical rotor core 121. The rotor core 121 is rotatably supported relative to the stator core 111. In this embodiment, the rotor 12 further includes a rotor shaft 122 connected to the rotor core 121 so as to rotate integrally with the rotor core 121. The rotor shaft 122 is formed to extend along a first axis X1. The rotor core 121 is fixed (e.g., press-fitted) to the rotor shaft 122, and end plates 125 are attached to both sides of the rotor core 121 in the axial direction L. In this embodiment, the rotor shaft 122 is formed in a cylindrical shape with the first axis X1 as its axis.

[0030] In this embodiment, the rotating electric machine 1 is an inner rotor type three-phase AC motor. That is, the stator 11 is disposed on the outer side of the rotor 12 in the radial direction R. Therefore, the stator core 111 is disposed on the outer side of the rotor core 121 in the radial direction R. Furthermore, the rotor shaft 122 is disposed on the inner side of the rotor core 121 in the radial direction R.

[0031] In this embodiment, the rotating electric machine 1 is a rotating field type rotating electric machine. Therefore, a stator coil is wound around the stator core 111. In this embodiment, the stator coil is wound around the stator core 111 so as to form a first coil end portion 112 that protrudes from the stator core 111 toward a first axial side L1 and a second coil end portion 113 that protrudes from the stator core 111 toward a second axial side L2. Although not shown, the rotor core 121 is provided with a permanent magnet. In this manner, the rotating electric machine 1 includes the stator core 111, the rotor core 121 rotatably supported by the stator core 111, and the cylindrical rotor shaft 122 that is connected to the rotor core 121 so as to rotate integrally with the rotor core 121, and serves as a drive source for the wheels WH (see FIG. 2 ).

[0032] The input member 2 is drivingly connected to the rotor 12 of the rotating electric machine 1. In this embodiment, the input member 2 includes an input gear 21 and an input shaft 22. The vehicle drive device 100 is provided in a power transmission path connecting the rotor shaft 122 and the wheels WH, and includes a drive transmission mechanism having the input shaft 22 spline-coupled to the rotor shaft 122. More specifically, an internal spline is formed on the inner peripheral surface of the rotor shaft 122, and an external spline is formed on the outer peripheral surface of the input shaft 22. The engagement of these internal and external splines allows the rotor shaft 122 and the input shaft 22 to rotate integrally. Note that an external spline may be formed on the outer peripheral surface of the rotor shaft 122, and an internal spline may be formed on the inner peripheral surface of the input shaft 22.

[0033] Here, in this application, the term "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, and includes a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at a variable speed, such as a shaft, a gear mechanism, a belt, a chain, etc. Note that the transmission members may also include engagement devices that selectively transmit rotation and driving force, such as a friction engagement device or a meshing engagement device.

[0034] The input gear 21 is connected to the input shaft 22 so as to rotate integrally with the input gear 21. In the example shown in FIG.

[0035] The input shaft 22 is formed to extend along the first axis X1. In this embodiment, the input shaft 22 penetrates the partition wall portion 91 of the case 9 in the axial direction L and is coupled to the rotor shaft 122 so as to rotate integrally with the rotor shaft 122. In the example shown in FIG. 1 , the end of the input shaft 22 on the first axial side L1 is disposed radially inward relative to the end of the rotor shaft 122 on the second axial side L2. These portions are coupled to each other by spline engagement so as to rotate integrally with the rotor shaft 122.

[0036] The counter gear mechanism 5 includes a counter input gear 51 that meshes with the input gear 21, a counter output gear 52 that rotates integrally with the counter input gear 51, and a counter shaft 53 that connects the gears 51 and 52 together.

[0037] The counter input gear 51 and the counter output gear 52 are connected to each other via a counter shaft 53 so as to rotate integrally. The counter shaft 53 is formed to extend along the third axis X3. In the example shown in FIG. 1 , the counter input gear 51 is connected to the counter shaft 53 by spline engagement. The counter output gear 52 is formed integrally with the counter shaft 53. In the example shown in FIG. 1 , the counter output gear 52 is formed to have a smaller diameter than the counter input gear 51. The counter output gear 52 is disposed closer to the first axial side L1 than the counter input gear 51. Although not shown, the output gear of the input shaft 22 may be connected to the input shaft 22 by spline engagement, and the counter input gear may be formed integrally with the counter shaft 53.

[0038] As shown in FIG. 1 , the parking mechanism 7 includes a parking gear 75. The input shaft 22 is connected to the parking gear 75 so as to rotate integrally with the parking gear 75. In the example shown in FIG. 1 , the input shaft 22 and the parking gear 75 are connected to each other by spline engagement. The parking mechanism 7 includes an engagement member (not shown) that selectively engages with the parking gear 75, and a second power transmission mechanism (not shown) that transmits power to the engagement member. The parking mechanism 7 (second power transmission mechanism) is configured to be drivable by a parking actuator 77 provided in a third case portion 9C of the case 9 (see FIGS. 3 and 4 ).

[0039] The present applicant has disclosed a parking mechanism in detail in Japanese Patent Laid-Open No. 2023-48738, and the matters disclosed in that application can be applied to the embodiments of the present invention.

[0040] The differential gear mechanism 4 is configured to distribute rotation transmitted from the input member 2 to the pair of output members 3. In this embodiment, the differential gear mechanism 4 includes a differential input gear 41 that is an input element of the differential gear mechanism 4. Therefore, the differential gear mechanism 4 distributes the rotation of the differential input gear 41 to the pair of output members 3.

[0041] In this embodiment, the differential gear mechanism 4 further includes a differential case 42, a pair of pinion gears 43, and a pair of side gears 44. Here, the pair of pinion gears 43 and the pair of side gears 44 are both bevel gears.

[0042] The differential case 42 is a hollow member that houses a pair of pinion gears 43 and a pair of side gears 44. The differential case 42 is connected to the differential input gear 41 so as to rotate integrally with the differential case 42. In the example shown in FIG. 1 , the differential input gear 41 is connected to the differential case 42 by bolting.

[0043] The pair of pinion gears 43 are disposed to face each other at a distance in the radial direction R based on the second axis X2. The pair of pinion gears 43 are attached to a pinion shaft 43a that is supported so as to rotate integrally with the differential case 42. Each of the pair of pinion gears 43 is configured to be rotatable (spin on its own axis) around the pinion shaft 43a and rotatable (revolve) around the second axis X2.

[0044] The pair of side gears 44 mesh with the pair of pinion gears 43. The pair of side gears 44 are arranged to rotate about the second axis X2 as a rotation axis center. The pair of side gears 44 are arranged to face each other with a gap between them in the axial direction L, with the pinion shaft 43 a sandwiched therebetween.

[0045] Each of the pair of output members 3 is drivingly coupled to a wheel WH (see FIG. 2 ). In this embodiment, each of the pair of output members 3 is coupled to the side gear 44 so as to rotate integrally therewith. In this embodiment, one of the pair of output members 3 penetrates the third side wall portion 94b in the axial direction L, and the other of the pair of output members 3 penetrates the fourth side wall portion 94c in the axial direction L. Each of the pair of output members 3 is coupled to a drive shaft DS, which is drivingly coupled to the wheel WH, so as to rotate integrally therewith. In the example shown in FIG. 1 , each of the pair of output members 3 is formed in a cylindrical shape with the second axis X2 as its axis. The drive shaft DS is disposed radially inward of each of the pair of output members 3 in the radial direction R, and the pair of output members 3 are coupled to each other by spline engagement.

[0046] The inverter device 10 is configured to control the rotating electric machine 1. In this embodiment, the inverter device 10 is electrically connected to the rotating electric machine 1 and the power storage device, and converts power between the direct current of the power storage device and the multiple-phase (three-phase in this case) alternating current of the rotating electric machine 1. In this example, the inverter device 10 includes a switching element unit having multiple switching elements that configure an inverter circuit, a smoothing capacitor that smooths the voltage on the DC power supply side of the inverter circuit, and a control board that controls the inverter circuit.

[0047] As shown in FIG. 3, the first case portion 9A of the case 9 is provided with an inlet 61 and an outlet 62 through which a cooling medium (liquid or gas) for cooling the inverter device 10 flows in and out.

[0048] In the following description, the up-down direction of the vehicle drive device 100 when mounted on the vehicle is referred to as the "up-down direction Z." The upper and lower sides of the "up-down direction Z" are simply referred to as the "upper side Z1" and the "lower side Z2," respectively. Furthermore, the direction perpendicular to the first axis X1 when viewed in the up-down direction along the up-down direction Z is referred to as the "width direction W."

[0049] 4, a breather opening 98 that connects the inside and outside of the second housing portion A2 is disposed on the Z1 side in the vertical direction Z of the case 9. A breather chamber 99 that opens into the second housing portion A2 and connects with the breather opening 98 is formed in the second housing portion A2. In this manner, the vehicle drive device 100 is configured so that the inside and outside of the second housing portion A2 can communicate with each other via the breather opening 98 and the breather chamber 99.

[0050] 3 and 4 , the vehicle drive device 100 has a lubricating oil supply passage 80. The lubricating oil supply passage 80 supplies lubricating oil from a lubricating oil inlet 85 formed in the motor-side space to the motor via an inlet passage 86 and an oil cooler 73. Specifically, the lubricating oil supply passage 80 supplies lubricating oil toward a first outlet E1, a second outlet E2, and a third outlet E3.

[0051] The first outlet E1 supplies lubricating oil to the rotor core 121. The second outlet E2 supplies lubricating oil to the coil ends of the stator core 111. The third outlet E3 supplies lubricating oil to a central lubricating oil passage 2a (see FIG. 4) formed coaxially with the first axis X1, which is the drive axis of the input member 2.

[0052] The lubricating oil supply passage 80 includes a first oil passage 81, a second oil passage 82, a third oil passage 83, and a fourth oil passage 84. The first oil passage 81 is formed from the oil cooler 73 toward the upper side Z1. The second oil passage 82 is formed from a tip end 81a of the first oil passage 81 along the axial direction L. The third oil passage 83 is formed from a tip end 82a of the second oil passage 82 toward the lower side Z2. A branch oil passage 82b toward the second outlet E2 is connected to the upper side Z1 of the third oil passage 83, and an oil passage toward the third outlet E3 is connected to the tip end 83a. In this embodiment, multiple second outlets E2 (three locations) are formed, and lubricating oil is supplied toward a bus bar (not shown) electrically connected to the UVW phases of the rotating electrical machine 1, which is a three-phase AC motor.

[0053] A fourth oil passage 84 branches off from the first oil passage 81. The fourth oil passage 84 is formed to be inclined in the axial direction L and the width direction W. The fourth oil passage 84 is connected to a plurality of first outlets E1 at both the branching portion and the tip portion, and supplies lubricating oil to the rotor core 121 in the axial direction L and the circumferential direction.

[0054] In the vehicle drive device 100, an electric oil pump OP (see FIGS. 4 and 7) is housed in the second housing portion A2 (see FIG. 1) of the first case portion 9A, for example, by bolts, and supplies lubricating and cooling oil to the rotating electric machine 1, etc., as described above. A power connector 87 (see FIG. 3) that supplies power to the electric oil pump OP is provided in the first case portion 9A. The power supplied from the power connector 87 is supplied to the electric oil pump OP via a power cable (not shown) arranged inside the second housing portion A2.

[0055] In addition to the oil supplied by the electric oil pump OP, oil scooped up by gears housed inside the case 9 is also supplied as lubricating and cooling oil. An oil reservoir is formed inside the case 9, particularly in the lower part of the equipment housing chamber, where the oil used for lubrication and cooling falls and accumulates. The oil accumulated in the oil reservoir is scooped up by gears (e.g., differential input gear 41) included in the vehicle drive device 100. The scooped up oil is supplied directly to parts to be lubricated, such as bearings, and is also accumulated in catch tanks 71 and 72 (see FIGS. 5 and 6 ) formed inside the case 9. The oil is then supplied to the parts to be lubricated via the catch tanks 71 and 72. As shown in FIGS. 5 and 6 , in this embodiment, the vehicle drive device 100 is provided with an upper catch tank 71 formed relatively on the upper side Z1 and a lower catch tank 72 formed relatively on the lower side Z2. The upper catch tank 71 and the lower catch tank 72 are connected to each other, and are configured so that oil stored in the upper catch tank 71 can be supplied to the lower catch tank 72 via an orifice. The oil stored in the upper catch tank 71 and the lower catch tank 72 is also supplied to each target part via the orifice.

[0056] The applicant of the present invention has disclosed in detail the arrangement of the electric oil pump OP in Japanese Patent Laid-Open No. 2023-48740. Therefore, the matters disclosed in this application can be applied to the embodiments of the present invention.

[0057] 6 and 7, the case 9 has an oil reservoir S, and a strainer 97 communicating with the electric oil pump OP is provided on a surface 9A1 provided on the first case portion 9A facing the oil reservoir S. As a result, the oil in the oil reservoir S can be sucked up into the electric oil pump OP via the strainer 97 and then supplied again to the rotating electrical machine 1, etc.

[0058] The present applicant has disclosed details of the strainer 97 in Japanese Patent Laid-Open No. 2023-146588. Therefore, the matters disclosed in this application can be applied to the embodiments of the present invention.

[0059] FIGS. 8 to 10 show a configuration example of the vehicle drive device 100 described above. As shown in FIGS. 8 to 10 , the vehicle drive device 100 is supported on a vehicle body (e.g., a cross member) via mounts 65. The mounts 65 are provided on the outer surfaces of the case 9. In this embodiment, the mounts 65 are provided on the front ( FIG. 8 ), one side ( FIG. 9 ), and the other side ( FIG. 10 ) of the vehicle drive device. In this embodiment, the mounts 65 include a first mount 66, a second mount 67, and a third mount 68. Each of the mounts 66, 67, and 68 is configured with a plurality of holes (four in this embodiment) for fastening fixing members such as bolts. As shown in FIG. 8 , the first mount 66 is provided on the front of the first case portion 9A. As shown in FIG. 9 , the second mount 67 is provided on the second case portion 9B disposed on the first axial side L1 of the case 9. As shown in FIG. 10, the third mount portion 68 is provided on the second axial side L2 of the first case portion 9A.

[0060] As shown in FIG. 11 , the vehicle drive device 100 of this embodiment is mounted on a vehicle VC for rear-wheel drive, for example. The side of the front wheels WF relative to the rear wheels WR in the vehicle fore-and-aft direction Y (see FIG. 11 ) is referred to as the fore-and-aft front side YF, and the opposite side is referred to as the fore-and-aft rear side YR. The direction perpendicular to the vehicle fore-and-aft direction Y is referred to as the vehicle width direction X. In this embodiment, the vehicle width direction X and the axial direction L coincide (see FIGS. 1 and 10 ). When the vehicle drive device 100 is mounted on a vehicle VC for rear-wheel drive, the second axis X2, the third axis X3, and the first axis X1 are arranged in this order in the vehicle fore-and-aft direction Y from the fore-and-aft front side YF to the fore-and-aft rear side YR.

[0061] Although not shown, the vehicle drive device 100 of this embodiment may be mounted on the vehicle VC for driving the front wheels WF, or may be mounted at the front and rear of the vehicle VC for driving the front wheels WF and the rear wheels WR. When the vehicle drive device 100 is mounted on the vehicle VC for driving the front wheels WF, the first axis X1, the third axis X3, and the second axis X2 are arranged in this order in the vehicle fore-and-aft direction Y from the front side YF to the rear side YR.

[0062] As shown in FIG. 1 , the rotating electric machine 1 includes a case 9 (an example of a housing) that houses a rotary electric machine 1 and a drive transmission mechanism (including a rotor shaft 122, an input shaft 22, an output member 3, a differential gear mechanism 4, and a counter gear mechanism 5). As shown in FIG. 12 , the rotor shaft 122 and the input shaft 22 of the drive transmission mechanism are disposed adjacent to a partition wall 91 (an example of a housing) of the case 9. The rotor shaft 122 is supported by the partition wall 91 via a first ball bearing 123 having a first inner ring 123 a and a first outer ring 123 b. The rotor shaft 122 is also supported by the case 9 via a third ball bearing 124 provided on the opposite side of the first ball bearing 123 and having a third inner ring 124 a and a third outer ring 124 b (see FIG. 1 ). The input shaft 22 is supported by the partition wall 91 via a second ball bearing 23 having a second inner ring 23 a and a second outer ring 23 b. In this embodiment, the second outer ring 23b is attached to the partition wall portion 91, and the rotor shaft 122 is assembled to the input shaft 22 so as to be spline-coupled with the input shaft 22, with the first outer ring 123b press-fitted onto the rotor shaft 122 and the second inner ring 23a press-fitted onto the input shaft 22. Therefore, a gap is formed between the inner circumferential surface of the first inner ring 123a and the outer circumferential surface of the rotor shaft 122. As a result, the biasing force of the elastic member S1 causes the first inner ring 123a of the first ball bearing 123 to move relative to the first outer ring 123b toward the rotor shaft 122, thereby suppressing rattle of the first ball bearing 123 on the rotor shaft 122. Furthermore, the movement of the first inner ring 123a causes the third inner ring 124a of the third ball bearing 124, which supports the rotor 12 via the rotor shaft 122, to move rightward in FIG. 1 , thereby suppressing rattle of the third ball bearing 124 on the rotor shaft 122.

[0063] A first inner ring 123a of the first ball bearing 123 is provided so as to be movable a predetermined amount in the axial direction L of the rotor shaft 122. An elastic member S1 is disposed between the first ball bearing 123 and the second ball bearing 23, which are adjacent to each other in the axial direction L of the rotor shaft 122 and the input shaft 22, to bias the first ball bearing 123 and the second ball bearing 23 in a direction separating them. The elastic member S1 is formed of, for example, a spring or rubber. In this embodiment, the elastic member S1 is formed in an entirely cylindrical shape and is disposed between the first inner ring 123a of the first ball bearing 123 and the second inner ring 23a of the second ball bearing 23.

[0064] Lubricating oil is supplied from the first outlet E1 to a space 30 surrounded by the partition wall portion 91, the elastic member S1, the first ball bearing 123, and the second ball bearing 23 (see FIG. 7 ). The space 30 is configured as a lubricating oil reservoir. Specifically, the elastic member S1 arranged on the inside in the radial direction R prevents lubricating oil from being discharged from the first outlet E1, so the space 30 functions as a lubricating oil reservoir. This allows an appropriate amount of lubricating oil to be supplied to the first ball bearing 123 and the second ball bearing 23 via the reservoir space 30, improving the lubrication of the first ball bearing 123 and the second ball bearing 23.

[0065] Second Embodiment In the second embodiment, as shown in FIG. 13 , an elastic member S2 is disposed between the first ball bearing 123 and the second ball bearing 23, which are adjacent to each other in the axial direction L of the rotor shaft 122 and the input shaft 22, to bias the first ball bearing 123 and the second ball bearing 23 in a direction separating them. In the second embodiment, the elastic member S2 is formed by a leaf spring that is convex outward in the radial direction R, and is disposed between the first inner ring 123 a of the first ball bearing 123 and the second inner ring 23 a of the second ball bearing 23. Furthermore, the elastic member S2 protrudes outward in the radial direction R beyond the outer diameter of the first inner ring 123 a. The elastic member S2 may protrude outward in the radial direction R beyond the outer diameter of the second inner ring 23 a, or may protrude outward in the radial direction R beyond one or both of the outer diameters of the first inner ring 123 a and the second inner ring 23 a. The other configurations are the same as those of the first embodiment.

[0066] 14 , in the third embodiment, an elastic member S3 is disposed between the first ball bearing 123 and the second ball bearing 23, which are adjacent to each other in the axial direction L of the rotor shaft 122 and the input shaft 22, to bias the first ball bearing 123 and the second ball bearing 23 in a direction separating them. In the third embodiment, the elastic member S3 is formed in an entirely cylindrical shape, similar to the elastic member S1 in the first embodiment. However, the elastic member S3 is disposed between the first inner ring 123a of the first ball bearing 123 and the end portion 122a of the rotor shaft 122 and the second inner ring 23a of the second ball bearing 23, which is a difference from the first embodiment. The other configurations are the same as those in the first embodiment.

[0067] 15 , in the third embodiment, an elastic member S4 is disposed between the first ball bearing 123 and the second ball bearing 23, which are adjacent to each other in the axial direction L of the rotor shaft 122 and the input shaft 22, to bias the first ball bearing 123 and the second ball bearing 23 in a direction separating them. In the fourth embodiment, the elastic member S4 is formed of a leaf spring, similar to the elastic member S2 in the second embodiment. However, the elastic member S4 is a leaf spring that is convex inward in the radial direction R, and is disposed between the first inner ring 123a of the first ball bearing 123 and the end portion 122a of the rotor shaft 122 and the second inner ring 23a of the second ball bearing 23, which is a difference from the second embodiment. The other configurations are the same as those in the first embodiment.

[0068] (a) The elastic member S2 of the second embodiment has been described as protruding outward in the radial direction R relative to either or both of the outer diameter of the first inner ring 123a and the outer diameter of the second inner ring 23a. Although not shown, the elastic member S1 of the first embodiment, the elastic member S3 of the third embodiment, and the elastic member S4 of the fourth embodiment may also protrude outward in the radial direction R relative to either or both of the outer diameter of the first inner ring 123a and the outer diameter of the second inner ring 23a.

[0069] (b) In the above embodiment, cylindrical elastic members and leaf springs are exemplified as elastic members S1 to S4, but elastic members S1 to S4 may have other shapes or configurations as long as they apply a force in a direction that separates first ball bearing 123 and second ball bearing 23.

[0070] (c) As shown in Fig. 16, the vehicle drive device 100 may have a soundproof cover C attached to the front side. The soundproof cover C is fixed by, for example, a plurality of bolts B (three in Fig. 16). Although not shown, the vehicle drive device 100 may have the soundproof cover C attached to the entire surface.

[0071] In the above-described embodiment, the following configuration is conceivable: (1) A vehicle drive device (100) includes a rotating electric machine (1) having a stator (11), a rotor (12) rotatably supported by the stator (11), and a cylindrical rotor shaft (122) connected to the rotor (12) so as to rotate integrally with the rotor (12), and serving as a drive source for wheels (WH), a drive transmission mechanism provided in a power transmission path connecting the rotor shaft (122) and the wheels (WH) and having an input shaft (22) coupled to the rotor shaft (122), and a housing (9) accommodating the rotating electric machine (1) and the drive transmission mechanism, and the rotor shaft (122) is a first The rotor shaft (122) is supported by the housing (9) via a first ball bearing (123) having an inner ring (123a) and a first outer ring (123b), and the input shaft (22) is supported by the housing (9) via a second ball bearing (23) having a second inner ring (23a) and a second outer ring (23b). Elastic members (S1, S2, S3, S4) are arranged between the first ball bearing (123) and the second ball bearing (23), which are adjacent to each other in the axial direction of the rotor shaft (122) and the input shaft (22), to bias the first ball bearing (123) and the second ball bearing (23) in a direction separating them.

[0072] According to this configuration, elastic members (S1, S2, S3, S4) are disposed between the first ball bearing (123) of the rotor shaft (122) and the second ball bearing (23) of the input shaft (22) and bias the first ball bearing (123) in a direction separating the first ball bearing (123) from the second ball bearing (23). For example, when the first inner ring (123a) of the first ball bearing (123) is movably provided on the rotor shaft (122), the biasing force of the elastic members (S1, S2, S3, S4) causes the first inner ring (123a) and the first outer ring (123b) to abut against the balls. As a result, under normal circumstances, the amount of rattle in the radial direction is reduced, thereby realizing smooth rotation of the rotating electric machine (1), and when an excessive force is applied, a force that counteracts the biasing force of the elastic members (S1, S2, S3, S4) causes the first inner ring (123a) and the first outer ring (123b) to move away from the balls, thereby preventing seizure of the first ball bearing (123). Furthermore, the biasing force of the elastic members (S1, S2, S3, S4) causes the first ball bearing (123) to move toward the rotor shaft (122), thereby suppressing rattle of the first ball bearing (123) on the rotor shaft (122). Furthermore, since the elastic members (S1, S2, S3, S4) are provided between the first ball bearing (123) and the second ball bearing (23) that are adjacent to each other in the axial direction of the rotor shaft (122) and the input shaft (22), i.e., for example, close to the spline connection of both shafts, they can also absorb machining errors in the spline connection.

[0073] Therefore, the vehicle drive device (100) can effectively suppress the rotation noise of the rotating electric machine (1).

[0074] (2) In the vehicle drive device (100) of (1), it is preferable that the elastic members (S1, S2, S3, S4) bias the first inner wheel (123a) and the first outer wheel (123b) in a direction that moves them relative to each other.

[0075] According to this configuration, the first inner ring (123a) and the first outer ring (123b) are moved relative to each other by the elastic members (S1, S2, S3, S4). That is, it is possible to smoothly switch between a state in which the first inner ring (123a) and the first outer ring (123b) abut against the balls due to the biasing force of the elastic members (S1, S2, S3, S4) and a state in which the first inner ring (123a) and the first outer ring (123b) are separated from the balls due to a force opposing the biasing force of the elastic members (S1, S2, S3, S4).

[0076] (3) In the vehicle drive device (100) of (1) or (2), it is preferable that the space surrounded by the housing (9), the elastic members (S1, S2, S3, S4), the first ball bearing (123), and the second ball bearing (23) is configured as a lubricating oil reservoir space (30).

[0077] According to this configuration, the space surrounded by the housing (9), the elastic members (S1, S2, S3, S4), the first ball bearing (123), and the second ball bearing (23) serves as a lubricating oil reservoir space (30), making it difficult for the lubricating oil supplied to the reservoir space (30) to be discharged to the outside. This allows an appropriate amount of lubricating oil to be supplied to the first ball bearing (123) and the second ball bearing (23) via the reservoir space (30), thereby improving the lubrication of the first ball bearing (123) and the second ball bearing (23).

[0078] (4) In the vehicle drive device (100) of (3), it is preferable that the elastic members (S1, S2, S3, S4) protrude radially (R) outward beyond the outer diameter of the first inner ring (123a) or the second inner ring (23a).

[0079] According to this configuration, the elastic members (S1, S2, S3, S4) can be properly abutted against predetermined positions including the upper end of the first inner ring (123a) or the second inner ring (23a). As a result, the elastic members (S1, S2, S3, S4) properly abut against the first inner ring (123a) or the second inner ring (23a), and therefore the biasing force of the elastic members (S1, S2, S3, S4) can be reliably applied to the first inner ring (123a) or the second inner ring (23a).

[0080] The present invention can be used in a vehicle drive device.

[0081] 1: rotating electric machine, 9: case (housing), 11: stator, 12: rotor, 22: input shaft, 23: second ball bearing, 23a: second inner ring, 23b: second outer ring, 30: reservoir space, 91: partition wall (housing), 122: rotor shaft, 123: first ball bearing, 123a: first inner ring, 123b: first outer ring, R: radial direction, S1, S2, S3, S4: elastic members, WH: wheel

Claims

1. A vehicle drive device comprising: a rotating electric machine having a stator, a rotor rotatably supported relative to the stator, and a cylindrical rotor shaft connected to rotate integrally with the rotor core, the rotating electric machine serving as a drive source for wheels; a drive transmission mechanism provided in a power transmission path connecting the rotor shaft and the wheels, the drive transmission mechanism having an input shaft connected to the rotor shaft; and a housing that accommodates the rotating electric machine and the drive transmission mechanism, wherein the rotor shaft is supported by the housing via a first ball bearing having a first inner ring and a first outer ring, the input shaft is supported by the housing via a second ball bearing having a second inner ring and a second outer ring, and an elastic member is disposed between the first ball bearing and the second ball bearing which are adjacent to each other in the axial direction of the rotor shaft and the input shaft, for biasing the first ball bearing and the second ball bearing in a direction separating them.

2. The vehicle drive device according to claim 1, wherein the elastic member biases the first inner ring and the first outer ring in a direction that moves the first inner ring and the first outer ring relative to each other.

3. The vehicle drive device according to claim 1 or 2, wherein a space surrounded by the housing, the elastic member, the first ball bearing, and the second ball bearing is configured as a space for storing lubricating oil.

4. The vehicle drive device according to claim 3, wherein the elastic member protrudes radially outward beyond an outer diameter of the first inner ring or the second inner ring.

Images