Vehicle drive device

Abstract

To provide a vehicle drive device which can achieve downsizing of a dimension in an axial direction.SOLUTION: A vehicle drive device (100) comprises a rotary electric machine (1), an input shaft (2), a pair of output members (3), a speed reduction mechanism (4), a differential gear mechanism (5), and a case (9). The speed reduction mechanism (4) decelerates rotation of the rotary electric machine (1). The input shaft (2) is connected to the rotary electric machine (1) so as to rotate integrally with the rotary electric machine (1). The differential gear mechanism (5) has a differential input member (51) and distributes the rotation transmitted from the speed reduction mechanism (4) to the pair of output members (3). The differential input member (51) is supported rotatably with respect to the case (9) through a first bearing (B31). The input shaft (2) is supported rotatably with respect to the differential input member (51) through a second bearing (B12). The first bearing (B31) is disposed so as to overlap the second bearing (B12) when seen in a radial direction (R).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle drive device including a rotating electric machine having a rotor and a speed reduction mechanism for reducing the rotation of the rotor.

Background Art

[0002] An example of such a vehicle drive device is disclosed in Patent Document 1 below. In the following description of the background art, the reference numerals and names in Patent Document 1 are cited in parentheses.

[0003] The vehicle drive device (rear transaxle 10) described in Patent Document 1 includes a rotating electric machine (motor 1), a speed reduction mechanism (first speed reduction gear pair 14, second speed reduction gear pair 16), a differential gear mechanism (differential mechanism 17), a case (20) for housing these, and a pair of output members (a pair of rear axles 18). In this vehicle drive device (rear transaxle 10), the rotating electric machine (motor 1) and the differential gear mechanism (differential mechanism 17) are arranged on the same axis, and the counter gear mechanism constituting the speed reduction mechanism (first speed reduction gear pair 14, second speed reduction gear pair 16) is arranged on an axis different from that of the rotating electric machine (motor 1) and the differential gear mechanism (differential mechanism 17). The rotation of the rotor (11a) of the rotating electric machine (motor 1) is reduced by the speed reduction mechanism (first speed reduction gear pair 14, second speed reduction gear pair 16) and transmitted to the pair of output members (a pair of rear axles 18) via the differential gear mechanism (differential mechanism 17).

[0004] In the vehicle drive device (rear transaxle 10) described in Patent Document 1, the rotor (11a) of the rotating electric machine (motor 1) is rotatably supported by the case (20) via an input shaft (output shaft 12) that rotates integrally with the rotor (11a) and a pair of bearings (output shaft bearings 21). Further, the differential gear mechanism (differential mechanism 17) is rotatably supported by the case (20) via a pair of bearings (27).

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2014-025491 Summary of the Invention Problems to be Solved by the Invention

[0006] In the vehicle drive device (rear transaxle 10) described in Patent Document 1, since the rotary electric machine (motor 1) and the differential gear mechanism (differential mechanism 17) are arranged on the same axis, the bearing (output shaft bearing 21) that supports the rotor (11a) and the bearing (17) that supports the differential gear mechanism (differential mechanism 17) are arranged side by side in the axial direction on the same axis. Therefore, the axial dimension of the vehicle drive device (rear transaxle 10) tends to be increased by the amount of axial space required for the arrangement of these bearings (output shaft bearing 21, bearing 17).

[0007] Therefore, it is desired to realize a vehicle drive device that is easy to reduce the axial dimension. Means for Solving the Problems

[0008] In view of the above, the characteristic configuration of the vehicle drive device includes a rotary electric machine having a rotor, an input shaft connected to rotate integrally with the rotor, a pair of output members each drivingly connected to a wheel, a speed reduction mechanism for reducing the rotation of the input shaft, a differential input member, and a differential gear mechanism for distributing the rotation transmitted from the speed reduction mechanism to the differential input member to the pair of output members, and a case for housing the rotary electric machine, the input shaft, the speed reduction mechanism, and the differential gear mechanism. The rotor, the input shaft, the pair of output members, and the differential gear mechanism are arranged on a first axis, the speed reduction mechanism is arranged on the first axis, and includes a first gear connected to rotate integrally with the input shaft, a second gear meshing with the first gear, and a third gear connected to rotate integrally with the second gear. A counter gear mechanism is arranged on a second axis which is a different axis from the first axis, and a fourth gear is arranged on the first axis, meshing with the third gear and connected to rotate integrally with the differential input member. The differential input member is rotatably supported by the case via a first bearing, the input shaft is rotatably supported by the differential input member via a second bearing, and in a radial view along the radial direction with the direction orthogonal to the first axis as the radial direction, the first bearing and the second bearing are arranged so as to overlap each other.

[0009] According to this characteristic configuration, since the differential input member of the differential gear mechanism is supported by the case via the first bearing and the input shaft is supported by the differential input member via the second bearing, it is possible to arrange the first bearing and the second bearing to overlap in a radial view while preventing the shape of the case from becoming complicated. And by arranging the first bearing and the second bearing to overlap in a radial view, it is easier to reduce the axial dimension of the vehicle drive device compared to a configuration where they are arranged in a non-overlapping positional relationship in a radial view.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0011] The vehicle drive device 100 according to the embodiment will be described with reference to FIGS. 1 to 3. As shown in FIGS. 1 and 2, the vehicle drive device 100 includes a rotating electric machine 1 having a rotor 12, an input shaft 2 connected to the rotor 12 so as to rotate integrally with the rotor 12, a pair of output members 3 each drivingly connected to a wheel W, a reduction gear mechanism 4, a differential gear mechanism 5, and a case 9. The reduction gear mechanism 4 and the differential gear mechanism 5 drivingly connect the input shaft 2 and the output member 3. The case 9 houses the rotating electric machine 1, the input shaft 2, the reduction gear mechanism 4, and the differential gear mechanism 5. In the present embodiment, the rotor 12 of the rotating electric machine 1, the input shaft 2, the pair of output members 3, and the differential gear mechanism 5 are arranged on the same axis (first axis X1).

[0012] Here, in the present application, "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 two or more transmission members. Such transmission members include various members that transmit rotation at the same speed or with speed change, for example, shafts, gear mechanisms, belts, chains, and the like. Note that the transmission members may include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices.

[0013] In the following description, the direction along the first axis X1 is defined as the "axial direction L" of the vehicle drive device 100. The direction orthogonal to the first axis X1 is defined as the "radial direction R". One side in the axial direction L is defined as the first axial side L1. The other side in the axial direction L is defined as the second axial side L2.

[0014] The rotating electrical machine 1 functions as a driving force source for the wheel W. The rotating electrical machine 1 has a function as a motor (electric motor) that generates power upon receiving power supply, and a function as a generator (electric generator) that generates power upon receiving driving force. Specifically, the rotating electrical machine 1 is electrically connected to a power storage device (not shown) such as a battery or a capacitor. Then, the rotating electrical machine 1 runs on the power stored in the power storage device to generate a driving force. Also, the rotating electrical machine 1 generates electricity by the driving force transmitted from the side of the wheel W to charge the power storage device.

[0015] The rotating electrical machine 1 further includes a stator 11. The stator 11 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 the case 9 as a non-rotating member. The rotor 12 of the rotating electrical machine 1 includes a cylindrical rotor core 121. The rotor core 121 is rotatably supported with respect to the stator core 111.

[0016] The speed reduction mechanism 4 reduces the rotation of the input shaft 2. The speed reduction mechanism 4 includes a first gear 4A connected to rotate integrally with the input shaft 2, a counter gear mechanism 41 including a second gear 4B and a third gear 4C, and a fourth gear 4D. The first gear 4A is disposed on the first axis X1. The counter gear mechanism 41 is drivingly connected to the first gear 4A via the second gear 4B. Also, the counter gear mechanism 41 is disposed on a second axis X2 which is a different axis from the first axis X1. In this example, the first axis X1 and the second axis X2 are parallel to each other. In this embodiment, the fourth gear 4D is drivingly connected to the differential input member 51. The fourth gear 4D shown in FIG. 1 is disposed on the first axis X1.

[0017] In this embodiment, as shown in FIGS. 1 and 2, the first gear 4A is connected to the rotor 12 by the input shaft 2. The input shaft 2 includes a shaft member connected to rotate integrally with the rotor 12. The connection structure between the input shaft 2 and the rotor 12 in this embodiment will be described later.

[0018] The counter gear mechanism 41 includes a second gear 4B and a third gear 4C. The second gear 4B meshes with the first gear 4A. The third gear 4C is connected so as to rotate integrally with the second gear 4B. In the present embodiment, the third gear 4C is connected to the second gear 4B via a counter shaft 411. The counter shaft 411 includes a shaft member that is connected so as to rotate integrally with the second gear 4B and the third gear 4C. In the example shown in FIGS. 1 and 3, the counter shaft 411 is formed so as to extend along the second axis X2. At least one of the second gear 4B or the third gear 4C is a separate member from the counter shaft 411 and is connected so as to rotate integrally with the counter shaft 411. And the remaining one of the second gear 4B or the third gear 4C is integrally formed on the counter shaft 411. In this example, the second gear 4B is a separate member from the counter shaft 411, and the third gear 4C is integrally formed on the counter shaft 411.

[0019] Here, the "separate member" refers to separate members separated in the state of parts before becoming the final product, and includes both those separable in the state of the final product and those joined inseparably in the state of the final product. Also included are both cases where the plurality of members constituting the "separate member" are of the same material and cases where they are of different materials from each other.

[0020] In the example shown in FIG. 1, the second gear 4B is formed with a larger diameter than the first gear 4A. Also, although not shown, the number of teeth of the second gear 4B is larger than the number of teeth of the first gear 4A. Therefore, when the rotation of the first gear 4A is transmitted to the second gear 4B, the rotation speed of the counter shaft 411 becomes slower than the rotation speed of the first gear 4A.

[0021] The fourth gear 4D meshes with the third gear 4C. In the example shown in FIG. 1, the fourth gear 4D is formed with a larger diameter than the third gear 4C. Although not shown, the number of teeth of the fourth gear 4D is larger than the number of teeth of the third gear 4C. Further, in the example shown in FIG. 1, the third gear 4C is formed with a smaller diameter than the second gear 4B. Therefore, in the axial direction L view, a fourth gear 4D (described later) that meshes with the third gear 4C can also be disposed at a position overlapping the second gear 4B. For this reason, it is easy to form the fourth gear 4D with a large diameter without increasing the radial dimension R of the vehicle drive device 100.

[0022] As shown in FIG. 1, the differential gear mechanism 5 includes a differential input member 51. The differential gear mechanism 5 distributes the rotation transmitted from the speed reduction mechanism 4 to the differential input member 51 to the pair of output members 3. In the present embodiment, the fourth gear 4D is connected so as to rotate integrally with the differential input member 51.

[0023] In the present embodiment, the rotor 12, the first gear 4A, the pair of output members 3, and the differential gear mechanism 5 are arranged in the order described from the axial first side L1 to the axial second side L2 on the first axis X1. And the radial R arrangement area of the differential gear mechanism 5 overlaps with the radial R arrangement area of the second gear 4B. Therefore, the radial R dimension of the entire vehicle drive device 100 becomes smaller as compared with the case where the radial R arrangement area of the differential gear mechanism 5 does not overlap with the radial R arrangement area of the second gear 4B.

[0024] Here, regarding the arrangement of two elements, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a part of the region where the virtual straight line intersects both of the two elements.

[0025] In the present embodiment, as shown in FIG. 3, the differential gear mechanism 5 further includes a pair of pinion gears 52 and a pair of side gears 53. Here, both the pair of pinion gears 52 and the pair of side gears 53 are bevel gears.

[0026] The differential input member 51 of this embodiment is a hollow member that houses a pair of pinion gears 52 and a pair of side gears 53. The differential input member 51 is connected so as to rotate integrally with the fourth gear 4D.

[0027] The pair of pinion gears 52 are arranged to face each other with a space in the radial direction R with respect to the first axis X1. And the pair of pinion gears 52 are attached to a pinion shaft 52a that is supported so as to rotate integrally with the differential input member 51. Each of the pair of pinion gears 52 is configured to be rotatable (self-rotate) about the pinion shaft 52a and rotatable (revolve) about the first axis X1.

[0028] The pair of side gears 53 mesh with the pair of pinion gears 52. The pair of side gears 53 are arranged to rotate about the first axis X1 as the rotation axis. The pair of side gears 53 are arranged with a space in the axial direction L between them and facing each other across the pinion shaft 52a.

[0029] As described above, the case 9 houses the rotary electric machine 1, the input shaft 2, the speed reduction mechanism 4, and the differential gear mechanism 5. In this embodiment, the case 9 also houses a pair of output members 3.

[0030] As shown in FIG. 1, in this embodiment, the case 9 includes a first housing portion A1 and a second housing portion A2 inside. The first housing portion A1 includes a space in which the rotary electric machine 1 is housed. The second housing portion A2 includes a space in which the speed reduction mechanism 4 and the differential gear mechanism 5 are housed.

[0031] In this embodiment, the case 9 includes a partition wall 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, and a support wall portion 94.

[0032] The partition portion 91 is formed so as to partition the first accommodating portion A1 and the second accommodating portion A2. In the present embodiment, the partition portion 91 is formed to extend in the radial direction R. That is, the partition portion 91 partitions the first accommodating portion A1 and the second accommodating portion A2 in the axial direction L.

[0033] The first peripheral wall portion 92a is formed so as to cover the outside of the rotating electrical machine 1 in the radial direction R. In the example shown in FIG. 1, the stator 11 of the rotating electrical machine 1 is fixed to the first peripheral wall portion 92a. In the present embodiment, the rotating electrical machine 1 is of an inner rotor type. That is, the stator 11 is arranged outside the rotor 12 in the radial direction R. Therefore, the stator core 111 is arranged outside the rotor core 121 in the radial direction R.

[0034] Further, in the present embodiment, the rotating electrical machine 1 is of a rotating field type. Therefore, a stator coil is wound around the stator core 111. The stator coil is wound around the stator core 111 such that a pair of coil end portions 112 protruding in the first axial side L1 and the second axial side L2 with respect to the stator core 111 are formed. Further, a permanent magnet 122 is provided on the rotor core 121.

[0035] The first side wall portion 92b is formed so as to cover the first axial side L1 of the rotating electrical machine 1. In the present embodiment, the first peripheral wall portion 92a is formed in a cylindrical shape with the first axial side L1 open. And the opening on the first axial side L1 of the first peripheral wall portion 92a is blocked by the first side wall portion 92b. On the other hand, the partition portion 91 is integrally provided at a portion of the first peripheral wall portion 92a on the second axial side L2 with respect to the rotating electrical machine 1.

[0036] The second circumferential wall portion 93a is formed to cover the outside in the radial direction R of the speed reduction mechanism 4 and the differential gear mechanism 5. The second side wall portion 93b is formed to cover the second side L2 in the axial direction of the speed reduction mechanism 4 and the differential gear mechanism 5. In the present embodiment, the second circumferential wall portion 93a is formed in a cylindrical shape with the second side L2 in the axial direction being open. And the opening on the second side L2 in the axial direction of the second circumferential wall portion 93a is blocked by the second side wall portion 93b. On the other hand, a partition wall portion 91 is integrally provided at a portion on the first side L1 in the axial direction with respect to the first gear 4A in the second circumferential wall portion 93a.

[0037] In the present embodiment, the first accommodation portion A1 is formed by the partition wall portion 91, the first circumferential wall portion 92a, and the first side wall portion 92b. That is, a space surrounded by the partition wall portion 91, the first circumferential wall portion 92a, and the first side wall portion 92b inside the case 9 is formed as the first accommodation portion A1.

[0038] Also, in the present embodiment, the second accommodation portion A2 is formed by the partition wall portion 91, the second circumferential wall portion 93a, and the second side wall portion 93b. That is, a space surrounded by the partition wall portion 91, the second circumferential wall portion 93a, and the second side wall portion 93b inside the case 9 is formed as the second accommodation portion A2.

[0039] In the present embodiment, the support wall portion 94 includes portions that support the input shaft 2 and the differential gear mechanism 5. The support wall portion 94 is disposed inside the case 9. In the example shown in FIG. 1, the support wall portion 94 is disposed inside the second accommodation portion A2 and extends from the outside in the radial direction R toward the inside. Also, the support wall portion 94 shown in FIG. 1 is a separate member from the second side wall portion 93b and is fixed to the second side wall portion 93b. The support wall portion 94 overlaps with the arrangement region in the axial direction L of at least one of the rotor 12 and the differential gear mechanism 5. Note that if the case 9 can support the input shaft 2 and the differential gear mechanism 5, the support wall portion 94 may be integral with the second side wall portion 93b. Note that the support wall portion 94 may be fixed to the second circumferential wall portion 93a or may be integral with the second circumferential wall portion 93a.

[0040] In this embodiment, the input shaft 2 with the rotor 12 fixed thereto is accommodated in the first accommodating portion A1 and the second accommodating portion A2, and is rotatably supported by the case 9. Further, the reduction mechanism 4 and the differential gear mechanism 5 are accommodated in the second accommodating portion A2, and are rotatably supported by the case 9. Hereinafter, the support structures of the input shaft 2, the reduction mechanism 4, and the differential gear mechanism 5 will be described.

[0041] In this embodiment, as shown in FIGS. 1 and 3, the input shaft 2 includes a first shaft end portion 21, a rotor fixing portion 22, a bearing fitting portion 23, a first gear connecting portion 24, and a second shaft end portion 25. The second shaft end portion 25 in this embodiment corresponds to the "second supported portion". The first shaft end portion 21, the rotor fixing portion 22, the bearing fitting portion 23, the first gear connecting portion 24, and the second shaft end portion 25 are arranged in the described order along the axial direction L from the first axial side L1 to the second axial side L2.

[0042] The first shaft end portion 21 is a portion supported by a first input bearing B11 described later. In the example shown in FIG. 1, the first shaft end portion 21 is formed in a cylindrical shape having an axis along the axial direction L.

[0043] The rotor 12 is fixed to the rotor fixing portion 22. The rotor fixing portion 22 is formed in a cylindrical shape having an axis along the axial direction L. In the example shown in FIG. 1, the rotor fixing portion 22 is arranged so as to project from the rotor 12 to each of the first axial side L1 and the second axial side L2 in the axial direction.

[0044] The bearing fitting portion 23 is fitted with a third input bearing B13 described later. In the example shown in FIG. 1, the bearing fitting portion 23 is formed in a cylindrical shape having an axis along the axial direction L.

[0045] The first gear connecting portion 24 includes a portion to which the first gear 4A is connected. The first gear 4A illustrated in FIGS. 1 and 3 is integrally formed on the outer peripheral surface of the first gear connecting portion 24. And the first gear connecting portion 24 illustrated in FIGS. 1 and 3 is a separate member from the first shaft end portion 21, the rotor fixing portion 22, and the bearing fitting portion 23, and is formed in a cylindrical shape having an axis along the axial direction L. The first gear connecting portion 24 has a structure that fits with the bearing fitting portion 23 and is spline-engaged with the bearing fitting portion 23.

[0046] The second shaft end portion 25 is a portion supported by a second input bearing B12 described later. In the example shown in FIGS. 1 and 3, the second shaft end portion 25 is a portion protruding toward the second side L2 in the axial direction with respect to the first gear 4A. Specifically, the second shaft end portion 25 is a member integral with the first gear connecting portion 24 and is formed in a cylindrical shape having an axis along the axial direction L.

[0047] As shown in FIG. 1, the rotor 12 and the input shaft 2 are connected to each other in a state where the inner peripheral surface of the rotor 12 and the outer peripheral surface of the input shaft 2 are in contact with each other. In the present embodiment, the inner peripheral surface of the rotor 12 is the inner peripheral surface of the rotor core 121. In the present embodiment, the outer peripheral surface of the input shaft 2 is the outer peripheral surface of the rotor fixing portion 22.

[0048] As shown in FIGS. 1 and 2, the input shaft 2 is rotatably supported with respect to the case 9 at three different positions along the axial direction L by the first input bearing B11, the second input bearing B12, and the third input bearing B13. The second input bearing B12 in the present embodiment corresponds to the "second bearing".

[0049] The first input bearing B11 is arranged on the first axial side L1 with respect to the rotor 12. The first input bearing B11 rotatably supports the input shaft 2. In the present embodiment, the first input bearing B11 is arranged to support the outer peripheral surface of the first shaft end portion 21 of the input shaft 2 from the outer side in the radial direction R. In the example shown in FIG. 1, the first side wall portion 92b of the case 9 includes a first bearing support portion 92c. The first bearing support portion 92c is formed in a cylindrical shape extending along the axial direction L so as to overlap the first shaft end portion 21 in the radial direction R inside the first shaft end portion 21. And the first input bearing B11 is arranged between the inner peripheral surface of the first bearing support portion 92c and the outer peripheral surface of the first shaft end portion 21.

[0050] The second input bearing B12 is arranged on the second axial side L2 with respect to the first gear 4A. The second input bearing B12 is arranged to rotatably support the second shaft end portion 25 provided on the input shaft 2. In the present embodiment, the second input bearing B12 is arranged to support the outer peripheral surface of the second shaft end portion 25 from the outer side in the radial direction R. And the second input bearing B12 is supported by the case 9 via a first end portion 511 and a first differential bearing B31, which will be described later.

[0051] As shown in FIG. 1, the third input bearing B13 is arranged between the rotor 12 and the first gear 4A in the axial direction L. The third input bearing B13 rotatably supports the input shaft 2. In the present embodiment, the third input bearing B13 is arranged to support the bearing fitting portion 23 from the outer side in the radial direction R. In this example, the third input bearing B13 is arranged to support the outer peripheral surface of the bearing fitting portion 23 from the outer side in the radial direction R. In the example shown in FIG. 1, the case 9 includes a third bearing support portion 91a that supports the third input bearing B13 from the outer side in the radial direction R. And the third input bearing B13 is supported by the third bearing support portion 91a. The third bearing support portion 91a is formed in a cylindrical shape extending along the axial direction L so as to overlap the bearing fitting portion 23 in the radial direction R outside the bearing fitting portion 23 of the input shaft 2.

[0052] The counter gear mechanism 41 is rotatably supported with respect to the case 9 by the first counter bearing B21 and the second counter bearing B22. In the example shown in FIGS. 1 and 3, the first counter bearing B21 and the second counter bearing B22 rotatably support the counter shaft 411. The first counter bearing B21 is disposed on the first axial side L1 with respect to the second gear 4B. The second counter bearing B22 is disposed on the second axial side L2 with respect to the third gear 4C. The second counter bearing B22 in the present embodiment corresponds to the "fourth bearing".

[0053] In the present embodiment, the first counter bearing B21 is arranged to support the outer peripheral surface of the end portion on the first axial side L1 of the counter shaft 411 from the outside in the radial direction R. In the example shown in FIGS. 1 and 3, the partition wall portion 91 of the case 9 includes a first counter bearing support portion 91b. The first counter bearing support portion 91b is formed in a cylindrical shape extending along the axial direction L so as to overlap the end portion on the first axial side L1 of the counter shaft 411 in the radial direction R outside the end portion on the first axial side L1 of the counter shaft 411. And the first counter bearing B21 is disposed between the inner peripheral surface of the first counter bearing support portion 91b and the outer peripheral surface of the end portion on the first axial side L1 of the counter shaft 411.

[0054] In the present embodiment, the second counter bearing B22 is arranged to support the outer peripheral surface of the end portion on the second axial side L2 of the counter shaft 411 from the outside in the radial direction R. In the example shown in FIGS. 1 and 3, the case 9 includes a second counter bearing support portion 93c. The second counter bearing support portion 93c is formed in a cylindrical shape extending along the axial direction L so as to overlap the end portion on the second axial side L2 of the counter shaft 411 in the radial direction R outside the end portion on the second axial side L2 of the counter shaft 411. And the second counter bearing B22 is disposed between the inner peripheral surface of the end portion on the second axial side L2 of the second counter bearing support portion 93c and the outer peripheral surface of the counter shaft 411.

[0055] In this embodiment, the differential gear mechanism 5 is rotatably supported with respect to the case 9 by the first differential bearing B31 and the second differential bearing B32. The first differential bearing B31 in this embodiment corresponds to the "first bearing". Also, the second differential bearing B32 in this embodiment corresponds to the "third bearing". In the example shown in FIG. 3, the differential input member 51 is rotatably supported with respect to the case 9 by the first differential bearing B31 and the second differential bearing B32. Specifically, the differential input member 51 is rotatably supported with respect to the case 9 via the first differential bearing B31 on the first side L1 in the axial direction L from the center position of the differential gear mechanism 5 in the axial direction L (differential gear center position). Supplementary, in the example shown in FIG. 1, the differential gear center position is the position of the axis of the pinion gear 52. Also, the differential input member 51 is rotatably supported with respect to the case 9 via the second differential bearing B32 on the second side L2 in the axial direction from the differential gear center.

[0056] The first differential bearing B31 is arranged so as to overlap with the second input bearing B12 in a radial direction R view. In the example shown in FIG. 1, the second input bearing B12 is included in the arrangement region of the first differential bearing B31 in the axial direction L. Therefore, compared with the case where the first differential bearing B31 and the second input bearing B12 are arranged so that the arrangement region of the first differential bearing B31 in the axial direction L and a part of the arrangement region of the second input bearing B12 in the axial direction L overlap, the dimension in the axial direction L of the vehicle drive device 100 shown in FIG. 1 can be reduced.

[0057] In this embodiment, the first differential bearing B31 is arranged to support the first end portion 511 provided on the first side L1 in the axial direction from the differential gear center position of the differential input member 51. The first end portion 511 in this embodiment corresponds to the "first supported portion". In the example shown in FIG. 3, the first end portion 511 is a portion that protrudes on the first side L1 in the axial direction in the differential input member 51. In addition, the first end portion 511 shown in FIG. 3 is formed in a cylindrical shape extending in the axial direction L.

[0058] In this embodiment, the first end portion 511 is rotatably supported by the first differential bearing B31 from the outside in the radial direction R. In the example shown in FIG. 3, the case 9 includes a first differential bearing support portion 94a. The first differential bearing support portion 94a is formed on the support wall portion 94. The first differential bearing support portion 94a is formed in a cylindrical shape extending along the axial direction L so as to overlap the first end portion 511 in the radial direction R view on the outside in the radial direction R than the first end portion 511. And the first differential bearing B31 is disposed between the inner peripheral surface of the first differential bearing support portion 94a and the outer peripheral surface of the first end portion 511. Therefore, the aforementioned second input bearing B12 is supported by the first differential bearing support portion 94a via the first end portion 511 and the first differential bearing B31.

[0059] In this embodiment, the second differential bearing B32 is disposed so as to support a second end portion 512 provided on the second side L2 in the axial direction from the differential gear center of the differential input member 51. The second end portion 512 in this embodiment corresponds to the "third supported portion". In the example shown in FIG. 1, the second end portion 512 is a portion protruding toward the second side L2 in the axial direction in the differential input member 51. In addition, the second end portion 512 is formed in a cylindrical shape having an axis along the axial direction L. Also, in the examples shown in FIGS. 1 and 3, the second side wall portion 93b of the case 9 includes a second differential bearing support portion 93d. The second differential bearing support portion 93d is formed in a cylindrical shape extending along the axial direction L so as to overlap the second end portion 512 in the radial direction R view on the outside in the radial direction R than the second end portion 512. And the second differential bearing B32 is disposed between the inner peripheral surface of the second differential bearing support portion 93d and the outer peripheral surface of the second end portion 512.

[0060] The second differential bearing B32 is arranged so as to overlap with the second counter bearing B22 in the radial direction R view. Further, the second counter bearing B22 is arranged so as to overlap with a portion on the first axial side L1 in the axial direction of the second end portion 512 of the differential input member 51 in the radial direction R view. In the example shown in FIGS. 1 and 3, the second differential bearing B32 and the second counter bearing B22 are arranged such that a part of the arrangement region of the second differential bearing B32 in the axial direction L (the part on the first axial side L1) overlaps with a part of the arrangement region of the second counter bearing B22 in the axial direction L (the part on the second axial side L2).

[0061] Preferably, as illustrated in FIGS. 1 and 3, at least a part of the second counter bearing B22 is arranged radially inside the fourth gear 4D in the radial direction R. And the second counter bearing B22 is arranged so as to overlap with an extending portion 54 extending in the radial direction R in the differential input member 51 in the axial direction L view. In the example shown in FIG. 3, the extending portion 54 includes a portion for fixing the fourth gear 4D to the differential input member 51 with a fastening member (a bolt in the example shown in FIG. 3). According to this configuration, the second counter bearing B22 can be arranged using the space generated on the second axial side L2 with respect to the differential input member 51. Therefore, it is easy to reduce the size of the vehicle drive device 100 in the radial direction R. Note that the extending portion 54 only needs to be a portion extending in the radial direction R in the differential input member 51, and is not limited to the portion for fixing the fourth gear 4D to the differential input member 51. For example, the extending portion 54 may be a portion for supporting the pinion shaft 52a in the differential input member 51, or a wall portion formed around the pinion gear 52 or the side gear 53.

[0062] In the present embodiment, each of the pair of output members 3 is connected so as to rotate integrally with the side gear 53. And each of the pair of output members 3 is connected so as to rotate integrally with a drive shaft DS that is drivingly connected to the wheel W. In the example shown in FIG. 1, each of the pair of output members 3 is formed in a cylindrical shape with the first axis X1 as the axis. And they are connected to each other by spline engagement in a state where the drive shaft DS is arranged inside the pair of output members 3 in the radial direction R.

[0063] 〔Other Embodiments〕 (1) In the above-described embodiment, the first shaft end portion 21, the rotor fixing portion 22, and the bearing fitting portion 23, and the first gear connecting portion 24 and the second shaft end portion 25 have been described for the input shaft 2 of separate members. However, the first shaft end portion 21, the rotor fixing portion 22, the bearing fitting portion 23, the first gear connecting portion 24, and the second shaft end portion 25 may be integrally formed. Conversely, the individual components constituting the input shaft 2 may be arbitrarily separable.

[0064] (2) In the above-described embodiment, it has been described that the first gear 4A is integrally formed with the first gear connecting portion 24. However, the first gear 4A and the first gear connecting portion 24 may be separate members. In such a case, the connection between the first gear 4A and the first gear connecting portion 24 includes, for example, spline connection, fastening by a fastening member such as a bolt, and joining by welding.

[0065] (3) In the above-described embodiment, the bevel gear type differential gear mechanism 5 has been illustrated and described. However, the differential gear mechanism 5 may be a planetary gear type. Also, the differential gear mechanism 5 may be a planetary gear type having a double pinion. In this case, the differential input member 51 becomes a member that rotates integrally with the ring gear. And the differential gear center position when the differential gear mechanism 5 is of the planetary gear type is the center position in the width direction of the pinion.

[0066] (4) In the above-described embodiment, it has been described that the first axis X1 and the second axis X2 are parallel to each other. However, a positional relationship in which some axes are three-dimensionally intersecting with respect to other axes may be acceptable. For example, the first axis X1 may have a positional relationship of three-dimensionally intersecting with respect to the second axis X2.

[0067] (5) In the above-described embodiment, it was explained that the second input bearing B12 is included within the arrangement region in the axial direction L of the first differential bearing B31. However, when the dimension of the second input bearing B12 in the axial direction L is larger than the dimension of the first differential bearing B31 in the axial direction L, the first differential bearing B31 may be included within the arrangement region in the axial direction L of the second input bearing B12. Also in this case, similar to the case where the dimension of the first differential bearing B31 in the axial direction L is larger than the dimension of the second input bearing B12 in the axial direction L, the dimension of the vehicle drive device 100 in the axial direction L shown in FIG. 1 can be reduced. Further, the first differential bearing B31 and the second input bearing B12 may be arranged such that a part of the arrangement region of the first differential bearing B31 in the axial direction L and a part of the arrangement region of the second input bearing B12 in the axial direction L overlap.

[0068] (6) In the above-described embodiment, it was explained that the second differential bearing B32 and the second counter bearing B22 are arranged such that a part of the arrangement region of the second differential bearing B32 in the axial direction L and a part of the arrangement region of the second counter bearing B22 in the axial direction L overlap. However, the second differential bearing B32 may be included within the arrangement region in the axial direction L of the second counter bearing B22. Conversely, when the dimension of the second differential bearing B32 in the axial direction L is larger than the dimension of the second counter bearing B22 in the axial direction L, the second counter bearing B22 may be included within the arrangement region in the axial direction L of the second differential bearing B32.

[0069] (7) In the above-described embodiment, the configuration in which the second counter bearing B22 is arranged so as to overlap with the portion (hereinafter referred to as the "target portion") on the first side L1 in the axial direction of the second end portion 512 of the differential input member 51 in the radial direction R view was explained. However, the second counter bearing B22 may be arranged on the second side L2 in the axial direction with respect to the target portion so as not to overlap with the target portion in the radial direction R view.

[0070] (8) In the above-described embodiment, the configuration in which the second differential bearing B32 and the second counter bearing B22 are arranged so as to overlap in the radial direction R view has been described. However, the second differential bearing B32 and the second counter bearing B22 may be arranged at different positions in the axial direction L so that they do not overlap in the radial direction R view.

[0071] (9) In addition, the configurations disclosed in the above-described embodiments can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction occurs. Regarding other configurations as well, all the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be appropriately made without departing from the spirit of the present disclosure.

[0072] Summary of this embodiment Hereinafter, a summary of the embodiment related to the vehicle drive device (100) described above will be described below.

[0073] The vehicle drive device (100) includes a rotary electric machine (1) having a rotor (12), an input shaft (2) connected to rotate integrally with the rotor (12), a pair of output members (3) each drivingly connected to a wheel (W), a speed reduction mechanism (4) for reducing the rotation of the input shaft (2), a differential input member (51), and a differential gear mechanism (5) for distributing the rotation transmitted from the speed reduction mechanism (4) to the differential input member (51) to the pair of output members (3). The vehicle drive device (100) also includes a case (9) for housing the rotary electric machine (1), the input shaft (2), the speed reduction mechanism (4), and the differential gear mechanism (5). The rotor (12), the input shaft (2), the pair of output members (3), and the differential gear mechanism (5) are arranged on a first axis (X1). The speed reduction mechanism (4) is arranged on the first axis (X1) and includes a first gear (4A) connected to rotate integrally with the input shaft (2), a second gear (4B) meshing with the first gear (4A), and a third gear (4C) connected to rotate integrally with the second gear (4B). The speed reduction mechanism (4) further includes a counter gear mechanism (41) arranged on a second axis (X2) which is an axis different from the first axis (X1), and a fourth gear (4D) arranged on the first axis (X1), meshing with the third gear (4C), and connected to rotate integrally with the differential input member (51). The differential input member (51) is rotatably supported by the case (9) via a first bearing (B31). The input shaft (2) is rotatably supported by the differential input member (51) via a second bearing (B12). In a radial direction (R) view along the radial direction (R) with the direction orthogonal to the first axis (X1) being the radial direction (R), the first bearing (B31) and the second bearing (B12) are arranged so as to overlap each other.

[0074] According to this configuration, the differential input member (51) of the differential gear mechanism (5) is supported by the case (9) via the first bearing (B31), and the input shaft (2) is supported by the differential input member (51) via the second bearing (B12). By adopting such a configuration, while preventing the shape of the case (9) from becoming complicated, it is possible to arrange the first bearing (B31) and the second bearing (B12) so that they overlap in the radial direction (R) view. And, by arranging the first bearing (B31) and the second bearing (B12) so that they overlap in the radial direction (R) view, it becomes easier to reduce the axial dimension (L) of the vehicle drive device (100) compared to a configuration where they are arranged in a positional relationship where they do not overlap in the radial direction (R) view.

[0075] In the vehicle drive device (100), the direction along the first axis (X1) is defined as the axial direction (L), one side of the axial direction (L) is defined as the first axial side (L1), the other side of the axial direction (L) is defined as the second axial side (L2), and with the center position of the differential gear mechanism (5) in the axial direction (L) being the differential gear center position, the rotor (12), the first gear (4A), and the differential gear mechanism (5) are arranged in the described order from the first axial side (L1) to the second axial side (L2) on the first axis (X1). The first bearing (B31) is arranged to support the first supported portion (511) provided on the first axial side (L1) of the differential input member (51) relative to the differential gear center position, and the second bearing (B12) is arranged to support the second supported portion (25) provided on the second axial side (L2) of the input shaft (2) relative to the first gear (4A).

[0076] According to this configuration, the input shaft (2) and the differential input member (51) can be appropriately supported, and the first bearing (B31) and the second bearing (B12) for supporting them can be appropriately arranged using the space surrounded by the first gear (4A), the second gear (4B), and the differential gear mechanism (5).

[0077] The vehicle drive device (100) is configured such that the differential input member (51) is rotatably supported by the case (9) via a third bearing (B32) on the second axial side (L2) with respect to the center position of the differential gear. The counter gear mechanism is rotatably supported by the case (9) via a fourth bearing (B22) on the second axial side (L2) with respect to the third gear (4C). In a radial direction (R) view, the third bearing (B32) and the fourth bearing (B22) are arranged to overlap each other.

[0078] According to this configuration, by arranging the third bearing (B32) and the fourth bearing (B22) to overlap each other in a radial direction (R) view, it is easier to reduce the axial dimension (L) of the vehicle drive device (100) compared to a configuration where they are arranged in a non-overlapping positional relationship in the radial direction (R).

[0079] In the vehicle drive device (100), the third bearing (B32) is arranged to support a third supported portion (512) provided on the second axial side (L2) with respect to the center position of the differential gear in the differential input member (51). The fourth bearing (B22) is arranged to overlap, in a radial direction (R) view, a portion on the first axial side (L1) with respect to the third supported portion (512) in the differential input member (51).

[0080] According to this configuration, the fourth bearing (B22) is arranged to overlap both the third bearing (B32) and a portion on the first axial side (L1) with respect to the third supported portion (512) in the differential input member (51) in a radial direction (R) view. Therefore, the fourth bearing (B22) can be arranged by utilizing the space generated outside the differential gear mechanism (5) in the radial direction (R). Thus, it is easier to reduce the size of the vehicle drive device (100).

Industrial Applicability

[0081] The technology according to the present disclosure can be used in a vehicle drive device including a rotating electric machine having a rotor and a speed reduction mechanism for reducing the rotation of the rotor.

Explanation of Reference Numerals

[0082] 100: Vehicle drive device, 1: Rotating electric machine, 12: Rotor, 2: Input shaft, 25: Second shaft end (second supported part), 3: Output member, 4: Reduction mechanism, 4A: First gear, 41: Counter gear mechanism, 4B: Second gear, 4C: Third gear, 4D: Fourth gear, 5: Differential gear mechanism, 51: Differential input member, 511: First end (first supported part), 512: Second end (third supported part), 9: Case, B12: Second input bearing (second bearing), B22: Second counter bearing (fourth bearing), B31: First differential bearing (first bearing), B32: Second differential bearing (third bearing), L: Axial direction, L1: First axial side, L2: Second axial side, R: Radial direction, WH: Wheel, X1: First axis center, X2: Second axis center

Claims

1. A rotating electrical machine having a rotor, An input shaft connected so as to rotate integrally with the rotor, A pair of output members each drivingly connected to a wheel, A speed reduction mechanism for reducing the rotation of the input shaft, A differential gear mechanism having a differential input member and distributing the rotation transmitted from the speed reduction mechanism to the differential input member to the pair of output members, A vehicle drive device comprising the rotating electrical machine, the input shaft, the speed reduction mechanism, and a case for housing the differential gear mechanism, The rotor, the input shaft, the pair of output members, and the differential gear mechanism are arranged on a first axis, The speed reduction mechanism is A first gear disposed on the first axis and connected so as to rotate integrally with the input shaft, A counter gear mechanism including a second gear meshing with the first gear and a third gear connected so as to rotate integrally with the second gear, the counter gear mechanism being disposed on a second axis which is an axis different from the first axis, A fourth gear disposed on the first axis, meshing with the third gear, and connected so as to rotate integrally with the differential input member, Comprising The differential input member is rotatably supported with respect to the case via a first bearing, The input shaft is rotatably supported with respect to the differential input member via a second bearing, Taking the direction orthogonal to the first axis as the radial direction, A vehicle drive device in which the first bearing and the second bearing are arranged so as to overlap in a radial view along the radial direction.

2. Taking the direction along the first axis as the axial direction, one side of the axial direction as the first axial side, the other side of the axial direction as the second axial side, and the central position of the differential gear mechanism in the axial direction as the differential gear center position, The rotor, the first gear, and the differential gear mechanism are arranged in the described order from the first axial side to the second axial side on the first axis, The first bearing is arranged to support a first supported portion provided on the first axial side of the differential gear center position in the differential input member, The vehicle drive device according to claim 1, wherein the second bearing is arranged to support a second supported portion provided on the second axial side of the input shaft with respect to the first gear.

3. The differential input member is rotatably supported with respect to the case via a third bearing on the second axial side of the differential gear center position. The counter gear mechanism is rotatably supported with respect to the case via a fourth bearing on the second side in the axial direction from the third gear. The vehicle drive device according to claim 2, wherein the third bearing and the fourth bearing are arranged so as to overlap each other in the radial direction view.

4. The third bearing is arranged to support a third supported portion provided on the second side in the axial direction from the differential gear center position in the differential input member. The vehicle drive device according to claim 3, wherein the fourth bearing is arranged so as to overlap a portion on the first side in the axial direction from the third supported portion in the differential input member in the radial direction view.

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