Vehicle drive device

Abstract

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 the 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).

Description

Vehicle drive unit

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

[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, the reference numerals and names in Patent Document 1 will be cited in parentheses.

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

[0004] In the vehicle drive system (rear transaxle 10) described in Patent Document 1, a rotor (11a) of a rotating electric machine (electric motor 1) is rotatably supported in a 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). Also, a differential gear mechanism (differential mechanism 17) is rotatably supported in the case (20) via a pair of bearings (27).

[0005] JP 2014-025491 A

[0006] In the vehicle drive system (rear transaxle 10) described in Patent Document 1, the rotating electric machine (electric motor 1) and the differential gear mechanism (differential mechanism 17) are arranged on the same axis, so 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, axial space is required to arrange these bearings (output shaft bearing 21, bearing 17), which tends to increase the axial dimension of the vehicle drive system (rear transaxle 10).

[0007] Therefore, it is desirable to realize a vehicle drive device that can easily be made smaller in axial dimension.

[0008] In view of the above, a characteristic configuration of a vehicle drive device is a vehicle drive device including: a rotating electric machine having a rotor; an input shaft connected to rotate integrally with the rotor; a pair of output members each drivingly connected to wheels; a speed reduction mechanism that reduces the rotation of the input shaft; a differential gear mechanism that includes differential input members and distributes the rotation transmitted from the speed reduction mechanism to the pair of output members; and a case that accommodates the rotating electric machine, the input shaft, the speed reduction mechanism, and the differential gear mechanism, wherein the rotor, the input shaft, the pair of output members, and the differential gear mechanism are arranged on a first axis, and the speed reduction mechanism is arranged on the first axis and rotates integrally with the input shaft. the differential input member is provided with a counter gear mechanism arranged on a second axis which is separate from the first axis, the counter gear mechanism comprising a first gear connected to the first gear, a second gear meshing with the first gear, and a third gear connected to rotate integrally with the second gear, the counter gear mechanism being arranged on a second axis which is separate from the first axis, and a fourth gear arranged on the first axis, meshing with the third gear and connected to rotate integrally with the differential input member, the differential input member being rotatably supported relative to the case via a first bearing, the input shaft being rotatably supported relative to the differential input member via a second bearing, the direction perpendicular to the first axis being defined as the radial direction, and the first bearing and the second bearing being arranged to overlap when viewed in the radial direction along the radial direction.

[0009] According to this characteristic configuration, the differential input member of the differential gear mechanism is supported on the case via the first bearing, and the input shaft is supported on the differential input member via the second bearing, which makes it possible to arrange the first bearing and the second bearing so that they overlap in a radial direction while keeping the shape of the case from becoming complicated. Furthermore, by arranging the first bearing and the second bearing so that they overlap in a radial direction, it is easier to reduce the axial dimension of the vehicle drive device compared to a configuration in which they are arranged in a positional relationship where they do not overlap in a radial direction.

[0010] 1 is a cross-sectional view of a vehicle drive device according to an embodiment; FIG. 2 is a skeleton diagram of a vehicle drive device according to an embodiment; FIG. 3 is an enlarged view of a reduction mechanism and a differential gear mechanism shown in FIG. 1;

[0011] A vehicle drive device 100 according to an 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 wheels W, a reduction mechanism 4, a differential gear mechanism 5, and a case 9. The reduction mechanism 4 and the differential gear mechanism 5 drivingly connect the input shaft 2 and the output members 3. The case 9 houses the rotating electric machine 1, the input shaft 2, the reduction mechanism 4, and the differential gear mechanism 5. In this 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 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 friction engagement devices and meshing engagement devices.

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

[0014] The rotating electric machine 1 functions as a driving force source for the wheels W. 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 the electric power stored in the electric storage device. The rotating electric machine 1 also generates power using the driving force transmitted from the wheels W to charge the electric storage device.

[0015] The rotating electric 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 a case 9 serving 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 supported rotatably relative to the stator core 111.

[0016] The reduction gear mechanism 4 reduces the rotation speed of the input shaft 2. The reduction gear mechanism 4 includes a first gear 4A connected to the input shaft 2 so as 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 a first axis X1. The counter gear mechanism 41 is drivingly connected to the first gear 4A via the second gear 4B. The counter gear mechanism 41 is also disposed on a second axis X2, which is separate 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 a differential input member 51. The fourth gear 4D shown in FIG. 1 is disposed on the first axis X1.

[0017] 1 and 2, in this embodiment, the first gear 4A is connected to the rotor 12 by an 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 to the second gear 4B so as to rotate integrally with it. In this 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 connected to the second gear 4B and the third gear 4C so as to rotate integrally with them. In the example shown in FIGS. 1 and 3 , the counter shaft 411 is formed to extend along the second axis X2. At least one of the second gear 4B and the third gear 4C is a separate member from the counter shaft 411 and is connected to the counter shaft 411 so as to rotate integrally with it. The remaining second gear 4B or the third gear 4C is formed integrally with 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 formed integrally with the counter shaft 411.

[0019] Here, "separate components" refers to separate components that are separated in the state of parts before becoming a final product, and includes both components that are separable in the state of the final product and components that are joined together so that they cannot be separated in the state of the final product. Also, it includes both cases where the multiple components that make up the "separate components" are made of the same material and cases where they are made of different materials.

[0020] 1, the second gear 4B has a larger diameter than the first gear 4A. Although not shown, the second gear 4B has a larger number of teeth than 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 fourth gear 4D has a larger number of teeth than the third gear 4C. Furthermore, in the example shown in FIG. 1, the third gear 4C is formed with a smaller diameter than the second gear 4B. Therefore, the fourth gear 4D (described later) that meshes with the third gear 4C can be disposed at a position overlapping with the second gear 4B when viewed in the axial direction L. Therefore, the fourth gear 4D can be easily formed with a large diameter without increasing the radial dimension R of the vehicle drive device 100.

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

[0023] In this embodiment, the rotor 12, the first gear 4A, the pair of output members 3, and the differential gear mechanism 5 are arranged on the first axis X1 in the order described above from the first axial side L1 to the second axial side L2. The arrangement area of ​​the differential gear mechanism 5 in the radial direction R overlaps with the arrangement area of ​​the second gear 4B in the radial direction R. Therefore, the dimension of the entire vehicle drive device 100 in the radial direction R is smaller than when the arrangement area of ​​the differential gear mechanism 5 in the radial direction R does not overlap with the arrangement area of ​​the second gear 4B in the radial direction R.

[0024] Here, with regard to the arrangement of two elements, "overlapping when viewed in a particular direction" means that when a virtual line parallel to the viewing direction is moved in each direction perpendicular to the virtual line, there is at least a partial area where the virtual line intersects with both of the two elements.

[0025] 3, in this embodiment, the differential gear mechanism 5 further includes a pair of pinion gears 52 and a pair of side gears 53. Here, the pair of pinion gears 52 and the pair of side gears 53 are both 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 to the fourth gear 4D so as to rotate integrally therewith.

[0027] The pair of pinion gears 52 are disposed to face each other at a distance in the radial direction R based on the first axis X1. 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 (spin on its own axis) 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 a rotation axis. The pair of side gears 53 are arranged to face each other with a gap between them in the axial direction L, with the pinion shaft 52a in between.

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

[0030] 1 , in this embodiment, the case 9 includes a first housing portion A1 and a second housing portion A2 therein. The first housing portion A1 includes a space for housing the rotating electric machine 1. The second housing portion A2 includes a space for housing the reduction mechanism 4 and the differential gear mechanism 5.

[0031] In this embodiment, the case 9 includes a partition wall portion 91 , a first peripheral wall portion 92 a , a first side wall portion 92 b , a second peripheral wall portion 93 a , a second side wall portion 93 b , and a support wall portion 94 .

[0032] 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 in 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.

[0033] The first peripheral wall portion 92a is formed to cover the outside of the rotating electric machine 1 in the radial direction R. In the example shown in Fig. 1 , the stator 11 of the rotating electric machine 1 is fixed to the first peripheral wall portion 92a. In this embodiment, the rotating electric machine 1 is an inner rotor type. That is, the stator 11 is disposed on the outside of the rotor 12 in the radial direction R. Therefore, the stator core 111 is disposed on the outside of the rotor core 121 in the radial direction R.

[0034] In this embodiment, the rotating electric machine 1 is 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 so as to form a pair of coil end portions 112 that protrude toward a first axial side L1 and a second axial side L2 with respect to the stator core 111. Furthermore, a permanent magnet 122 is provided in the rotor core 121.

[0035] The first side wall portion 92b is formed to cover the first axial side L1 of the rotating electrical machine 1. In this embodiment, the first circumferential wall portion 92a is formed in a cylindrical shape that is open 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 provided on a portion of the first circumferential wall portion 92a that is on the second axial side L2 with respect to the rotating electrical machine 1.

[0036] The second peripheral wall portion 93a is formed to cover the outside of the reduction gear mechanism 4 and the differential 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 reduction gear mechanism 4 and the differential gear mechanism 5. In this embodiment, the second peripheral wall portion 93a is formed in a cylindrical shape that is open on the second axial side L2. The opening of the second peripheral wall portion 93a on the second axial side L2 is closed by the second side wall portion 93b. Meanwhile, a partition wall portion 91 is integrally provided on a portion of the second peripheral wall portion 93a on the first axial side L1 with respect to the first gear 4A.

[0037] 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.

[0038] 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 inside the case 9 surrounded by the partition wall 91, the second peripheral wall 93a, and the second side wall 93b forms the second storage section A2.

[0039] In the present embodiment, the support wall portion 94 includes a portion that supports 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 housing portion A2 and extends from the outer side toward the inner side in the radial direction R. 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 area of ​​at least one of the rotor 12 and the differential gear mechanism 5 as viewed in the axial direction L. Note that, as long as 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 to which the rotor 12 is fixed is housed in the first housing portion A1 and the second housing portion A2, and is rotatably supported by the case 9. The second housing portion A2 also houses the reduction mechanism 4 and the differential gear mechanism 5, and these are rotatably supported by the case 9. The support structures for the input shaft 2, the reduction mechanism 4, and the differential gear mechanism 5 will be described below.

[0041] 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. In this embodiment, the second shaft end portion 25 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 listed order along the axial direction L, from the first axial side L1 toward the second axial side L2.

[0042] The first shaft end portion 21 is a portion that is supported by a first input bearing B11, which will be described later. In the example shown in Fig. 1, the first shaft end portion 21 is formed in a cylindrical shape having an axis that is aligned with 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 disposed so as to protrude from the rotor 12 to both a first axial side L1 and a second axial side L2.

[0044] A third input bearing B13, which will be described later, is fitted into the bearing fitting portion 23. In the example shown in Fig. 1, the bearing fitting portion 23 is formed in a cylindrical shape having an axis aligned with 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 Figures 1 and 3 is integrally formed on the outer circumferential surface of the first gear connecting portion 24. The first gear connecting portion 24 illustrated in Figures 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 with an axis aligned with the axial direction L. The first gear connecting portion 24 is structured to fit with the bearing fitting portion 23, and is spline-engaged with the bearing fitting portion 23.

[0046] The second shaft end 25 is a portion supported by a second input bearing B12 (described later). In the example shown in Figures 1 and 3, the second shaft end 25 is a portion that protrudes toward the second axial side L2 relative to the first gear 4A. More specifically, the second shaft end 25 is a member that is integral with the first gear connecting portion 24, and is formed in a cylindrical shape with an axis that aligns with the axial direction L.

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

[0048] 1 and 2, the input shaft 2 is rotatably supported by a first input bearing B11, a second input bearing B12, and a third input bearing B13 at three different positions along the axial direction L. The second input bearing B12 in this embodiment corresponds to the "second bearing."

[0049] The first input bearing B11 is disposed on a 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 disposed so as to support the outer peripheral surface of the first shaft end 21 of the input shaft 2 from the outside 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, on a position inside the first shaft end 21 in the radial direction R, so as to overlap with the first shaft end 21 as viewed in the radial direction R. The first input bearing B11 is disposed between the inner peripheral surface of the first bearing support portion 92c and the outer peripheral surface of the first shaft end 21.

[0050] The second input bearing B12 is disposed on the second axial side L2 with respect to the first gear 4A. The second input bearing B12 is disposed to rotatably support the second shaft end portion 25 of the input shaft 2. In the present embodiment, the second input bearing B12 is disposed to support the outer peripheral surface of the second shaft end portion 25 from the outside in the radial direction R. 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 disposed 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 disposed so as 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 disposed so as 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. 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 with the bearing fitting portion 23 as viewed in the radial direction R, on the outer side of the bearing fitting portion 23 of the input shaft 2 in the radial direction R.

[0052] The counter gear mechanism 41 is rotatably supported relative to the case 9 by a first counter bearing B21 and a 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 closer to the first axial side L1 than the second gear 4B. The second counter bearing B22 is disposed closer to the second axial side L2 than the third gear 4C. In this embodiment, the second counter bearing B22 corresponds to the "fourth bearing."

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

[0054] In the present embodiment, the second counter bearing B22 is disposed so as to support the outer peripheral surface of the end portion of the counter shaft 411 on the second axial side L2 from the outside in the radial direction R. In the example shown in FIGS. 1 and 3 , the case 9 is provided with 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 of the counter shaft 411 on the second axial side L2 as viewed in the radial direction R, further outward in the radial direction R than the end portion of the counter shaft 411 on the second axial side L2. The second counter bearing B22 is disposed between the inner peripheral surface of the end portion of the second counter bearing support portion 93c on the second axial side L2 and the outer peripheral surface of the counter shaft 411.

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

[0056] The first differential bearing B31 is disposed so as to overlap with the second input bearing B12 when viewed in the radial direction R. In the example shown in Fig. 1 , the second input bearing B12 is included within the arrangement area of ​​the first differential bearing B31 in the axial direction L. Therefore, the dimension in the axial direction L of the vehicle drive device 100 shown in Fig. 1 can be made smaller than in a case where the first differential bearing B31 and the second input bearing B12 are disposed so that the arrangement area of ​​the first differential bearing B31 in the axial direction L overlaps with a portion of the arrangement area of ​​the second input bearing B12 in the axial direction L.

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

[0058] In this embodiment, the first end 511 is rotatably supported by the first differential bearing B31 from the outer side 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, outward of the first end 511 in the radial direction R, so as to overlap with the first end 511 as viewed in the radial direction R. The first differential bearing B31 is disposed between the inner circumferential surface of the first differential bearing support portion 94a and the outer circumferential surface of the first end 511. Therefore, the second input bearing B12 is supported by the first differential bearing support portion 94a via the first end 511 and the first differential bearing B31.

[0059] In the present embodiment, the second differential bearing B32 is disposed to support a second end 512 provided on the second axial side L2 relative to the center of the differential gear of the differential input member 51. In the present embodiment, the second end 512 corresponds to the "third supported portion." In the example shown in FIG. 1 , the second end 512 is a portion of the differential input member 51 that protrudes toward the second axial side L2. In addition, the second end 512 is formed in a cylindrical shape having an axis along the axial direction L. In the example 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, radially outward of the second end 512 and overlapping with the second end 512 as viewed in the radial direction R. The second differential bearing B32 is disposed between the inner circumferential surface of the second differential bearing support portion 93d and the outer circumferential surface of the second end 512.

[0060] The second differential bearing B32 is disposed so as to overlap with the second counter bearing B22 as viewed in the radial direction R. Furthermore, the second counter bearing B22 is disposed so as to overlap with a portion of the differential input member 51 that is closer to the first axial side L1 than the second end 512 as viewed in the radial direction R. In the example shown in FIGS. 1 and 3 , the second differential bearing B32 and the second counter bearing B22 are disposed so that a portion of the arrangement area of ​​the second differential bearing B32 in the axial direction L (a portion on the first axial side L1) overlaps with a portion of the arrangement area of ​​the second counter bearing B22 in the axial direction L (a portion on the second axial side L2).

[0061] Preferably, as illustrated in FIGS. 1 and 3 , at least a portion of the second counter bearing B22 is disposed radially inward of the fourth gear 4D. The second counter bearing B22 is disposed so as to overlap an extending portion 54 of the differential input member 51 extending in the radial direction R, as viewed in the axial direction L. In the example illustrated in FIG. 3 , the extending portion 54 includes a portion for fastening the fourth gear 4D to the differential input member 51 with a fastening component (a bolt in the example illustrated in FIG. 3 ). This configuration allows the second counter bearing B22 to be disposed by utilizing space generated on the second axial side L2 of the differential input member 51. This facilitates miniaturization of the radial direction R dimension of the vehicle drive device 100. The extending portion 54 may be any portion of the differential input member 51 that extends in the radial direction R, and is not limited to a portion for fastening the fourth gear 4D to the differential input member 51. For example, the extension portion 54 may be a portion of the differential input member 51 that supports the pinion shaft 52 a or a wall portion formed around the pinion gear 52 or the side gear 53 .

[0062] In this embodiment, each of the pair of output members 3 is connected to the side gear 53 so as to rotate integrally therewith. Each of the pair of output members 3 is connected to a drive shaft DS, which is drivingly connected to the wheels W, 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 first axis X1 as its axis. The drive shaft DS is disposed inside each of the pair of output members 3 in the radial direction R, and the pair of output members 3 are connected to each other by spline engagement.

[0063] Other Embodiments (1) In the above embodiment, the input shaft 2 is described in which the first shaft end portion 21, the rotor fixing portion 22, and the bearing fitting portion 23 are separate members from the first gear connecting portion 24 and the second shaft end portion 25. 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 that make up the input shaft 2 may be freely separable.

[0064] (2) In the above embodiment, the first gear 4A is described as being 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 may be achieved by, for example, spline connection, fastening with a fastening member such as a bolt, or joining by welding.

[0065] (3) In the above embodiment, the differential gear mechanism 5 is described as a bevel gear type. However, the differential gear mechanism 5 may be a planetary gear type. Furthermore, the differential gear mechanism 5 may be a planetary gear type equipped with a double pinion. In this case, the differential input member 51 is a member that rotates integrally with the ring gear. When the differential gear mechanism 5 is a planetary gear type, the center position of the differential gear is the center position in the width direction of the pinion.

[0066] (4) In the above embodiment, the first axis X1 and the second axis X2 are described as being parallel to each other. However, some axes may be in a positional relationship in which they intersect with other axes. For example, the first axis X1 may be in a positional relationship in which it intersects with the second axis X2.

[0067] (5) In the above embodiment, the second input bearing B12 is described as being included within the arrangement area of ​​the first differential bearing B31 in the axial direction L. However, if 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 area of ​​the second input bearing B12 in the axial direction L. In this case, as in 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 shown in FIG. 1 in the axial direction L can be reduced. Furthermore, the first differential bearing B31 and the second input bearing B12 may be arranged so that a portion of the arrangement area of ​​the first differential bearing B31 in the axial direction L overlaps a portion of the arrangement area of ​​the second input bearing B12 in the axial direction L.

[0068] (6) In the above embodiment, the second differential bearing B32 and the second counter bearing B22 are described as being arranged so that a portion of the arrangement area of ​​the second differential bearing B32 in the axial direction L overlaps a portion of the arrangement area of ​​the second counter bearing B22 in the axial direction L. However, the second differential bearing B32 may be included in the arrangement area of ​​the second counter bearing B22 in the axial direction L. Conversely, if 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 in the arrangement area of ​​the second differential bearing B32 in the axial direction L.

[0069] (7) In the above embodiment, the second counter bearing B22 is disposed so as to overlap a portion of the differential input member 51 that is closer to the first axial side L1 than the second end 512 (hereinafter referred to as the "target portion") when viewed in the radial direction R. However, the second counter bearing B22 may be disposed closer to the second axial side L2 than the target portion so as not to overlap with the target portion when viewed in the radial direction R.

[0070] (8) In the above embodiment, the second differential bearing B32 and the second counter bearing B22 are arranged so as to overlap when viewed in the radial direction R. 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 when viewed in the radial direction R.

[0071] (9) Note that the configurations disclosed in the above-described embodiments can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure.

[0072] Summary of the Present Embodiment The following provides a summary of the embodiment relating to the vehicle drive device (100) described above.

[0073] The vehicle drive device (100) includes a rotating 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) that reduces the rotation of the input shaft (2), and a differential gear mechanism (51) that distributes the rotation transmitted from the speed reduction mechanism (4) to the differential input member (51) to the pair of output members (3). and a case (9) that houses the rotating electric machine (1), the input shaft (2), the reduction gear mechanism (4), and the differential gear mechanism (5), wherein 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), and the reduction gear mechanism (4) is arranged on the first axis (X1) and is connected to the input shaft (2) so as to rotate integrally with the input shaft (2). a counter gear mechanism (41) disposed on a second axis (X2) which is an axis different from the first axis (X1); a fourth gear (4C) disposed on the first axis (X1), which meshes with the third gear (4C) and is connected to rotate integrally with the differential input member (51); D), wherein the differential input member (51) is rotatably supported relative to the case (9) via a first bearing (B31), the input shaft (2) is rotatably supported relative to the differential input member (51) via a second bearing (B12), and the direction perpendicular to the first axis (X1) is defined as a radial direction (R), and the first bearing (B31) and the second bearing (B12) are arranged to overlap when viewed in the radial direction (R) along the radial direction (R).

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

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

[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 positioned by utilizing the space surrounded by the first gear (4A), the second gear (4B), and the differential gear mechanism (5).

[0077] In the vehicle drive device (100), the differential input member (51) is rotatably supported relative to the case (9) via a third bearing (B32) on the second axial side (L2) of the differential gear center position, and the counter gear mechanism is rotatably supported relative to the case (9) via a fourth bearing (B22) on the second axial side (L2) of the third gear (4C), and is arranged so that the third bearing (B32) and the fourth bearing (B22) overlap when viewed in the radial direction (R).

[0078] According to this configuration, the third bearing (B32) and the fourth bearing (B22) are arranged so as to overlap when viewed in the radial direction (R), which makes it easier to reduce the axial (L) dimension of the vehicle drive device (100) compared to a configuration in which they are arranged in a positional relationship in which they do not overlap when viewed 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) of the differential gear center position in the differential input member (51), and the fourth bearing (B22) is arranged to overlap with a portion of the differential input member (51) that is on the first axial side (L1) of the third supported portion (512) when viewed in the radial direction (R).

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

[0081] The technology disclosed herein can be used in a vehicle drive device that includes a rotating electric machine having a rotor and a speed reduction mechanism that reduces the rotation speed of the rotor.

[0082] 100: Vehicle drive device, 1: Rotating electric machine, 12: Rotor, 2: Input shaft, 25: Second shaft end (second supported portion), 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 portion), 512: Second end (third supported portion), 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 shaft center, X2: Second shaft center

Claims

1. A vehicle drive device comprising: a rotating 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 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; and a case for housing the rotating electric machine, the input shaft, the speed reduction mechanism, and the differential gear mechanism, wherein 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 includes: a first gear arranged on the first axis and connected 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 to rotate integrally with the second gear, the counter gear mechanism being arranged on a second axis which is a different axis from the first axis; and a fourth gear 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 the first bearing and the second bearing are arranged so as to overlap in a radial direction view along the radial direction with the direction orthogonal to the first axis being the radial direction.

2. With the direction along the first axis being the axial direction, one side of the axial direction being the first axial side, the other side of the axial direction being the second axial side, and the central position of the differential gear mechanism in the axial direction being 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 input member with respect to the differential gear center position, and 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. The vehicle drive device according to claim 1.

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

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

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