Vehicular drive device

Abstract

This vehicular drive device (100) comprises a rotary electric machine (1), a pair of output members (3), a speed reduction mechanism (4), and a differential gear mechanism (5). The speed reduction mechanism (4) decelerates the rotation of the rotary electric machine (1). The differential gear mechanism (5) distributes the rotation transmitted from the speed reduction mechanism (4) to the pair of output members (3). The speed reduction mechanism (4) comprises a first gear (4A), a first counter gear mechanism (41), a second counter gear mechanism (42), and a sixth gear (4F) that rotate by means of the rotary electric machine (1). The first counter gear mechanism (41) is coupled to the first gear (4A). The second counter gear mechanism (42) is coupled to the first counter gear mechanism (41). The sixth gear (4F) drives and is coupled to the second counter gear mechanism (42) and the differential gear mechanism (5).

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 device (vehicle electric drive unit 1) described in Patent Document 1 includes a rotating electric machine (electric motor 3), a reduction mechanism (T), a differential transmission mechanism (differential device D), and a pair of output members (left and right output shafts 10L, 10R). The rotation of a rotor (rotor shaft 4) of the rotating electric machine (electric motor 3) is reduced in speed by the reduction mechanism (T) and transmitted to the pair of output members (left and right output shafts 10L, 10R) via the differential gear mechanism (differential device D).

[0004] The reduction gear mechanism (4) of the vehicle drive device (vehicle electric drive unit 1) described in Patent Document 1 is composed of a pair of counter gear mechanisms arranged parallel to a rotor (rotor shaft 4). Each of the pair of counter gear mechanisms includes a second gear (reduction gear 15) that meshes with a first gear (pinion gear 8) that rotates integrally with the rotor (rotor shaft 4), and a third gear (reduction gear 16) that rotates integrally with the second gear (reduction gear 15) and transmits rotation to a differential gear mechanism (differential device D). The third gear transmits rotation to the differential gear mechanism (differential device D) by meshing with a fourth gear (ring gear 20) provided in the differential gear mechanism (differential device D).

[0005] Japanese Patent Application Laid-Open No. 2019-173833

[0006] Incidentally, in order to increase the reduction ratio of the reduction mechanism (T) described in Patent Document 1, the radial dimensions of the second gear (reduction gear 15) and the fourth gear (ring gear 20) must be increased. In other words, when a large reduction ratio is ensured for the reduction mechanism (T), the vehicle drive device (vehicle electric drive unit 1) tends to become larger in the radial direction.

[0007] Therefore, it is desirable to realize a vehicle drive device that is easily downsized while ensuring a large reduction ratio of the reduction mechanism in a configuration that includes the reduction mechanism.

[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, a pair of output members each drivingly connected to a wheel, a speed reduction mechanism that reduces the rotation of the rotor, and 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, wherein the rotor, 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 includes a first gear that is connected to the rotor so as to rotate integrally with the rotor, and a second gear that is connected to the first gear. a first counter gear mechanism including a second gear meshing with the third gear and a third gear connected to rotate integrally with the second gear, the first counter gear mechanism being disposed on a second axis separate from the first axis; a second counter gear mechanism including a fourth gear meshing with the third gear and a fifth gear connected to rotate integrally with the fourth gear, the second counter gear mechanism being disposed on a third axis separate from the first axis and the second axis; and a sixth gear that is disposed on the first axis, meshes with the fifth gear, and is connected to rotate integrally with the differential input member.

[0009] According to this characteristic configuration, the rotation of the rotor can be reduced at three points before being transmitted to the differential gear mechanism: the meshing portion between the first gear and the second gear, the meshing portion between the third gear and the fourth gear, and the meshing portion between the fifth gear and the sixth gear. Therefore, compared to a configuration that includes only one counter gear mechanism between the rotor and the differential gear mechanism, it is easier to reduce the diameters of the multiple gears while ensuring a sufficient reduction ratio. Therefore, it is easier to reduce the overall size of the vehicle drive device. Furthermore, according to this configuration, the reduction mechanism can be constructed using a relatively simple combination of gears, which makes it easier to improve transmission efficiency and reduce manufacturing costs compared to a configuration that uses a planetary gear mechanism as the reduction mechanism.

[0010] A cross-sectional view of a vehicle drive device according to an embodiment. A skeleton diagram of a vehicle drive device according to an embodiment. A diagram showing the positional relationship of each element in an axial view of a vehicle drive device according to an embodiment. A cross-sectional view showing a refrigerant flow path of a vehicle drive device according to an embodiment.

[0011] A vehicle drive system 100 according to an embodiment will be described with reference to FIGS. 1 to 4. As shown in FIGS. 1 and 2, the vehicle drive system 100 includes a rotating electric machine 1 having a rotor 12, a pair of output members 3 each drivingly connected to a wheel WH, 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 rotor 12 to the output members 3. The case 9 illustrated in FIG. 1 houses the rotating electric machine 1, the reduction mechanism 4, and the differential gear mechanism 5. In this embodiment, the vehicle drive system 100 includes an inverter unit 6 for controlling the rotating electric machine 1. The inverter unit 6 illustrated in FIG. 1 is housed in the case 9.

[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] Furthermore, "coupled to rotate integrally" means that a state in which two rotating elements are coupled to rotate integrally (hereinafter referred to as an "integrally rotating state") can be realized. That is, "coupled to rotate integrally" includes both a mode in which the integrally rotating state is always realized (a mode in which the elements are coupled to rotate integrally) and a mode in which the integrally rotating state is selectively realized (a mode in which the elements can be coupled to rotate integrally).

[0014] The rotating electric machine 1 functions as a driving force source for the wheels WH. The rotating electric machine 1 has a function as a motor (electric motor) that receives a supply of electric power to generate power, and a function as a generator that receives a supply of power to generate electric power. Specifically, the rotating electric machine 1 is electrically connected to an electric storage device (not shown) such as a battery or a capacitor. The rotating electric machine 1 generates driving force by running using electric power stored in the electric storage device. The rotating electric machine 1 also generates power using driving force transmitted from the wheels WH to charge the electric storage device.

[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 mechanism 4 reduces the rotation speed of the rotor 12. The reduction mechanism 4 includes a first gear 4A connected to the rotor 12 so as to rotate integrally therewith, a first counter gear mechanism 41, a second counter gear mechanism 42, and a differential input gear 4F. In this embodiment, the first gear 4A is connected to the rotor 12 so as to rotate integrally therewith, and the rotor 12 and the first gear 4A are always connected to rotate integrally therewith. The first gear 4A is disposed on a first axis X1. The first counter gear mechanism 41 is connected to the first gear 4A. The first counter gear mechanism 41 is disposed on a second axis X2, which is a different axis from the first axis X1. The second counter gear mechanism 42 is connected to the first counter gear mechanism 41. The second counter gear mechanism 42 is disposed on a third axis X3, which is a different axis from the first axis X1 and the second axis X2. In this example, the first axis X1, the second axis X2, and the third axis X3 are parallel to one another. The differential input gear 4F is connected to the second counter gear mechanism 42. The differential input gear 4F is also disposed on the first axis X1. The differential input gear 4F is also drivingly connected to the differential gear mechanism 5. The differential input gear 4F corresponds to the "sixth gear."

[0017] 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. Furthermore, as shown in FIG. 3 , the direction perpendicular to the first axis X1 when viewed in the up-down direction is referred to as the "width direction W" of the vehicle drive device 100. Here, the up-down direction is the direction along the vertical direction when the vehicle drive device 100 is mounted on the vehicle (the up-down direction in FIGS. 3 and 4 ). In this example, both the second axis X2 and the third axis X3 are disposed on one side of the first axis X1 in the width direction W. In this example, the second axis X2 is disposed above the third axis X3, and the first axis X1 is disposed between the second axis X2 and the third axis X3 in the up-down direction. Furthermore, the direction perpendicular to the rotational axis of a rotating member such as the rotor 12 is referred to as the "radial direction R" based on each rotational axis. Note that when it is not necessary to distinguish which rotation axis is used as the reference or when it is clear which rotation axis is used as the reference, it may be simply 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.

[0018] In this embodiment, the rotor 12, the pair of output members 3, and the differential gear mechanism 5 are disposed on the first axis X1. Furthermore, in this embodiment, both the first counter gear mechanism 41 and the second counter gear mechanism 42 are disposed so as to overlap with the rotating electric machine 1 when viewed in the axial direction L. In addition, the first counter gear mechanism 41 and the second counter gear mechanism 42 are disposed so as to overlap with each other when viewed in the axial direction L. Note that with regard to the arrangement of two elements, "overlapping when viewed in a specific direction" means that when an imaginary line parallel to the line of sight is moved in each direction perpendicular to the imaginary line, there is at least a region in which the imaginary line intersects with both of the two elements.

[0019] In this embodiment, as shown in FIGS. 1 and 2 , the first gear 4A is connected to the rotor 12 via the rotor shaft 2. The rotor shaft 2 includes a shaft member connected to the rotor 12 so as to rotate integrally with the rotor 12. The rotor shaft 2 is fixed to the rotor 12. The first gear 4A is fixed to the rotor shaft 2. In this example, the first gear 4A is a separate member from the rotor shaft 2 and is connected to the rotor shaft 2 so as to rotate integrally with the rotor shaft 2. Here, the term "separate member" refers to a separate member that is separated from the rotor shaft 2 before it is made into a final product, and includes both a member that is separable in the final product and a member that is joined inseparably in the final product. Furthermore, the term "separate member" also includes a case where multiple members constituting the "separate member" are made of the same material and a case where they are made of different materials. For example, the connection between the rotor shaft 2 and the first gear 4A includes a spline connection, fastening with a fastening member such as a bolt, and joining by welding. Note that the first gear 4A may be formed integrally with the rotor shaft 2.

[0020] The first 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 so as to rotate integrally with it, and the second gear 4B and the third gear 4C are always connected to rotate integrally with it. In this embodiment, the third gear 4C is connected to the second gear 4B via a first counter shaft 411. The first 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. At least one of the second gear 4B and the third gear 4C is a separate member from the first counter shaft 411 and is connected to the first counter shaft 411 so as to rotate integrally with it. The remaining second gear 4B or third gear 4C is formed integrally with the first counter shaft 411. In this example, the second gear 4B is a separate member from the first counter shaft 411, and the third gear 4C is formed integrally with the first counter shaft 411.

[0021] In the example shown in FIG. 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 first countershaft 411 is slower than the rotation speed of the first gear 4A. Furthermore, in the example shown in FIG. 1 , the third gear 4C has a smaller diameter than the second gear 4B. Therefore, a fourth gear 4D (described later) that meshes with the third gear 4C can be positioned at a position overlapping the second gear 4B when viewed in the axial direction L. This makes it easy to form the fourth gear 4D with a large diameter without increasing the width direction W dimension of the vehicle drive device 100.

[0022] The second counter gear mechanism 42 includes a fourth gear 4D and a fifth gear 4E. The fourth gear 4D meshes with the third gear 4C. The fifth gear 4E is connected to the fourth gear 4D so as to rotate integrally with it. In this embodiment, the fifth gear 4E is connected to the fourth gear 4D so as to rotate integrally with it, and the fourth gear 4D and the fifth gear 4E are always connected to rotate integrally with it. In this embodiment, the fourth gear 4D is connected to the fifth gear 4E via a second counter shaft 421. The second counter shaft 421 includes a shaft member connected to the fourth gear 4D and the fifth gear 4E so as to rotate integrally with them. At least one of the fourth gear 4D and the fifth gear 4E is a separate member from the second counter shaft 421 and is connected to the second counter shaft 421 so as to rotate integrally with it. The remaining fourth gear 4D or fifth gear 4E is formed integrally with the second counter shaft 421. In this example, the fourth gear 4D is a separate member from the second counter shaft 421, and the fifth gear 4E is formed integrally with the second counter shaft 421. The fifth gear 4E meshes with the differential input gear 4F. In the example shown in FIG. 1 , the differential input gear 4F is formed with a larger diameter than the fifth gear 4E. Although not shown, the differential input gear 4F has more teeth than the fifth gear 4E. Therefore, when the rotation of the fifth gear 4E is transmitted to the differential input gear 4F, the rotational speed of the differential input gear 4F is slower than the rotational speed of the fifth gear 4E.

[0023] In the example shown in FIG. 1 , the fourth gear 4D has 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. Therefore, when the rotation of the third gear 4C is transmitted to the fourth gear 4D, the rotation speed of the second countershaft 421 becomes slower than the rotation speed of the first countershaft 411. Furthermore, in the example shown in FIG. 1 , the fifth gear 4E has a smaller diameter than the fourth gear 4D. Therefore, the differential input gear 4F meshing with the fifth gear 4E can be positioned overlapping the fourth gear 4D when viewed in the axial direction L. This makes it easy to form the differential input gear 4F with a large diameter without increasing the width direction W dimension of the vehicle drive device 100.

[0024] In this embodiment, the third gear 4C and the fourth gear 4D are disposed closer to the second axial side L2 than the first gear 4A and the second gear 4B. The fifth gear 4E and the differential input gear 4F are disposed closer to the second axial side L2 than the third gear 4C and the fourth gear 4D. Therefore, the differential input gear 4F is disposed farther from the rotating electric machine 1 than the first gear 4A, the second gear 4B, the third gear 4C, and the fourth gear 4D. Therefore, the differential input gear 4F can overlap the second gear 4B, the third gear 4C, and the fourth gear 4D when viewed in the axial direction L. Therefore, the differential input gear 4F can be formed with a large diameter without increasing the overall dimension of the vehicle drive device 100 when viewed in the axial direction L (e.g., the dimension in the width direction W). In other words, it is easy to configure the reduction ratio of the reduction mechanism 4 to be large without increasing the overall dimension of the vehicle drive device 100 as viewed in the axial direction L (for example, the dimension in the width direction W).

[0025] In addition, in the present embodiment, the gear with a larger outer diameter (large diameter gear) of the gears included in the first counter gear mechanism 41 and the gear with a larger outer diameter (large diameter gear) of the gears included in the second counter gear mechanism 42 overlap with the rotating electric machine 1 when viewed in the axial direction L. In the example shown in FIG. 1 , the second gear 4B and the fourth gear 4D overlap with the rotating electric machine 1 when viewed in the axial direction L. This makes it easy to reduce the overall dimension of the vehicle drive device 100 in the width direction W. Furthermore, in the present embodiment, the large diameter gear of the first counter gear mechanism 41 overlaps with the large diameter gear of the second counter gear mechanism 42 when viewed in the axial direction L. In the example shown in FIG. 1 , the second gear 4B and the fourth gear 4D overlap with each other when viewed in the axial direction L. This makes it easy to reduce the overall dimension of the vehicle drive device 100 in the width direction W.

[0026] In this embodiment, as shown in Fig. 3, the entire first counter gear mechanism 41 and the entire second counter gear mechanism 42 are disposed on one side of the first axis X1 in the width direction W. In the example shown in Fig. 3, the entire first counter gear mechanism 41 and the entire second counter gear mechanism 42 are disposed on the left side of the first axis X1 as viewed in the drawing. Therefore, the distance from the second axis X2 to the third axis X3 in the width direction W is smaller than when the entire first counter gear mechanism 41 is disposed on the opposite side of the first axis X1 from the entire second counter gear mechanism 42. Therefore, it is easy to reduce the dimension of the entire vehicle drive device 100 in the width direction W.

[0027] 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 differential input gear 4F is connected to the differential input member 51 so as to rotate integrally therewith.

[0028] In this embodiment, the rotor 12, the first gear 4A, 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 axial direction L overlaps with the arrangement areas of the third gear 4C and the fourth gear 4D in the axial direction L. Therefore, the dimension of the entire vehicle drive device 100 in the axial direction L is smaller than when the arrangement area of ​​the differential gear mechanism 5 in the axial direction L does not overlap with the arrangement areas of the third gear 4C and the fourth gear 4D in the axial direction L.

[0029] 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.

[0030] 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 differential input gear 4F so as to rotate integrally therewith.

[0031] 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.

[0032] 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.

[0033] The inverter unit 6 of this embodiment includes a modularized configuration of an inverter circuit (not shown) connected to a battery (not shown) that stores power, a rotating electric machine control unit (not shown), a driver (not shown), and a heat sink for cooling the inverter circuit.

[0034] The inverter circuit includes multiple switching elements. The inverter circuit includes multiple sets of arms for one AC phase, each consisting of a series circuit of an upper-stage switching element on the positive side of DC and a lower-stage switching element on the negative side. A freewheel diode is provided adjacent to each switching element, with the forward direction being from the negative pole to the positive pole. As the switching element, for example, an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a SiC-MOSFET (Silicon Carbide - Metal Oxide Semiconductor FET), a SiC-SIT (SiC - Static Induction Transistor), and a GaN-MOSFET (Gallium Nitride - MOSFET) can be used.

[0035] For example, a smoothing capacitor (not shown) is provided between the inverter circuit and the battery. The smoothing capacitor smoothes the voltage on the DC side of the inverter circuit. The smoothing capacitor may or may not be included in the inverter unit 6. A boost converter may also be provided, and in this case, the boost converter may be included in the inverter unit 6. The inverter unit 6 has, for example, a plurality of connection terminals (not shown) corresponding to the stator coils (not shown) of each phase of the stator 11 in the rotating electric machine 1. The inverter unit 6 is connected to the stator coils of each phase via these plurality of connection terminals.

[0036] The rotating electric machine control unit controls the switching of multiple switching elements that make up the inverter circuit to convert DC power supplied from the battery into multiple-phase AC power. The rotating electric machine control unit performs current feedback control based on the rotational position of the rotor 12 (magnetic pole position of the permanent magnets 122), the rotational speed of the rotor 12, and the current flowing through the stator coils of each of the three phases. The rotational position of the rotor 12 is detected by a rotation sensor (not shown) such as a resolver or an inductive position sensor. The current flowing through the stator coils is detected by a current sensor (not shown). The driver amplifies the voltage of the switching control signal output from the rotating electric machine control unit, increases the driving force, and supplies it to the inverter circuit.

[0037] In the present embodiment, at least a portion of the inverter unit 6 (for example, the smoothing capacitor described above) is disposed between the rotating electric machine 1 and the differential input gear 4F in the axial direction L, and overlaps with both the rotating electric machine 1 and the differential input gear 4F as viewed in the axial direction L. In the example shown in FIG. 1 , the inverter unit 6 is disposed between the stator 11 of the rotating electric machine 1 and the differential input gear 4F in the axial direction L, and overlaps with both the stator 11 and the differential input gear 4F as viewed in the axial direction L. More specifically, in the example shown in FIG. 1 , the inverter unit 6 is disposed between the coil end portion 112 of the stator 11 and the differential input gear 4F in the axial direction L, and overlaps with both the coil end portion 112 and the differential input gear 4F as viewed in the axial direction L.

[0038] As described above, the case 9 accommodates the rotating electric machine 1, the reduction gear mechanism 4, and the differential gear mechanism 5. In this embodiment, the case 9 also accommodates a pair of output members 3.

[0039] 1 , in this embodiment, the case 9 includes a first housing section A1, a second housing section A2, and a third housing section A3 therein. The first housing section A1 includes a space for housing the rotating electric machine 1. The second housing section A2 includes a space for housing the speed reduction mechanism 4 and the differential gear mechanism 5. The third housing section A3 includes a space for housing the inverter unit 6.

[0040] In this embodiment, the case 9 includes a partition portion 91, a first peripheral wall portion 92a, a first side wall 92b, a second peripheral wall portion 93a, a second side wall portion 93b, an intermediate wall portion 94, a third side wall portion 95a, and a wall portion 95b.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] The first side wall 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 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In the present embodiment, the intermediate wall portion 94 supports at least one of the rotor 12, the reduction gear mechanism 4, and the differential gear mechanism 5 within the case 9. The intermediate wall portion 94 extends from the outer side to the inner side in the radial direction R within the second housing portion A2. In the example shown in FIG. 1 , the intermediate wall portion 94 is fixed to the second circumferential wall portion 93a. The intermediate wall portion 94 overlaps with the arrangement areas of at least one of the rotor 12, the first counter gear mechanism 41, the second counter gear mechanism 42, and the differential gear mechanism 5 as viewed in the axial direction L. In addition, in the example shown in FIG. 1 , a portion of the intermediate wall portion 94 is disposed within the second housing portion A2 between the area where the first counter gear mechanism 41 is disposed and the area where the second counter gear mechanism 42 is disposed. Specifically, the intermediate wall portion 94 includes a portion disposed on the second axial side L2 relative to the third gear 4C and a portion disposed on the first axial side L1 relative to the fourth gear 4D. The third gear 4C and the fourth gear 4D mesh with each other through the intermediate wall portion 94. More specifically, as shown in FIG. 1 , the intermediate wall portion 94 has a communication portion that connects the area where the third gear 4C is located with the area where the fourth gear 4D is located. The third gear 4C and the fourth gear 4D mesh with each other through the communication portion. Note that the intermediate wall portion 94 does not need to be provided as long as the case 9 can support the rotor 12, the reduction mechanism 4, and the differential gear mechanism 5.

[0049] The third side wall portion 95a is formed to cover the outside of the inverter unit 6 in the axial direction L and the width direction W. In the example shown in FIG. 1 , the third side wall portion 95a is formed to extend outward in the radial direction R from the outer circumferential surfaces of the first circumferential wall portion 92a and the second circumferential wall portion 93a. The wall portion 95b covers the inverter unit 6 from the outside in the radial direction R (here, from the upper side). In this embodiment, the third accommodation portion A3 is formed by the first circumferential wall portion 92a, the second circumferential wall portion 93a, the third side wall portion 95a, and the wall portion 95b. In other words, the space inside the case 9 surrounded by the first circumferential wall portion 92a, the second circumferential wall portion 93a, the third side wall portion 95a, and the wall portion 95b defines the third accommodation portion A3. In the example shown in FIG. 1, the inverter unit 6 is accommodated in the third accommodation portion A3 so as to face both the first peripheral wall portion 92a and the second peripheral wall portion 93a.

[0050] In this embodiment, the rotor 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 speed reduction mechanism 4 and the differential gear mechanism 5 are housed in the second housing portion A2, and are rotatably supported by the case 9. The support structure for the rotor shaft 2, the speed reduction mechanism 4, and the differential gear mechanism 5 will be described below.

[0051] In this embodiment, the rotor 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 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.

[0052] The first shaft end portion 21 is supported by a first bearing B1, which will be described later. In the example shown in FIG. 1 , the first shaft end portion 21 is formed into a cylindrical shape with an axis along the axial direction L. The rotor 12 is fixed to the rotor fixing portion 22. In this embodiment, the rotor fixing portion 22 is formed into a cylindrical shape with 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 toward both a first axial side L1 and a second axial side L2. The outer diameter of the rotor fixing portion 22 is smaller than that of the first shaft end portion 21. A third bearing B3, which will be described later, is fitted into the bearing fitting portion 23. The first gear connecting portion 24 is a portion to which the first gear 4A is connected. In this example, the first gear 4A is spline-engaged with the first gear connecting portion 24. The second shaft end portion 25 is supported by a second bearing B2, which will be described later. In the example shown in FIG. 1, the second shaft end portion 25 is formed in a cylindrical shape having an axis aligned with the axial direction L.

[0053] 1, the rotor 12 and the rotor shaft 2 are connected to each other with the inner peripheral surface of the rotor 12 and the outer peripheral surface of the rotor shaft 2 in contact with each other. 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 rotor shaft 2 is the outer peripheral surface of the rotor fixing portion 22. The rotor 12 and the first gear 4A are disposed at different positions in the axial direction L. The first gear 4A is disposed on a second axial side L2 relative to the rotor 12.

[0054] As shown in FIGS. 1 and 2, the rotor shaft 2 is rotatably supported relative to the case 9 at three locations in the axial direction L by a first bearing B1, a second bearing B2, and a third bearing B3.

[0055] The first bearing B1 is disposed on a first axial side L1 relative to the rotor 12. The first bearing B1 rotatably supports the rotor shaft 2. In the present embodiment, the first bearing B1 is disposed so as to support the inner circumferential surface of the first shaft end portion 21 of the rotor shaft 2 from the inside in the radial direction R. In the example shown in FIG. 1 , the first side wall 92b of the case 9 includes a first bearing support portion 92c. The first bearing support portion 92c is formed in a cylindrical shape that protrudes toward the second axial side L2, located inside the first shaft end portion 21 in the radial direction R, so as to overlap with the first shaft end portion 21 as viewed in the radial direction R. The first bearing B1 is disposed between the outer circumferential surface of the first bearing support portion 92c and the inner circumferential surface of the first shaft end portion 21.

[0056] The second bearing B2 is disposed on the second axial side L2 relative to the first gear 4A. The second bearing B2 rotatably supports the second shaft end portion 25 of the rotor shaft 2. In the present embodiment, the second bearing B2 is disposed so as to support the outer peripheral surface of the second shaft end portion 25 from the outside in the radial direction R. In the example shown in FIG. 1 , the case 9 includes a second bearing support portion 94a. The second bearing support portion 94a is formed on the intermediate wall portion 94. The second bearing support portion 94a is formed in a cylindrical shape that protrudes toward the first axial side L1, outward of the second shaft end portion 25 in the radial direction R, so as to overlap with the second shaft end portion 25 as viewed in the radial direction R. The second bearing B2 is disposed between the inner peripheral surface of the second bearing support portion 94a and the outer peripheral surface of the second shaft end portion 25.

[0057] The third bearing B3 is disposed between the rotor 12 and the first gear 4A in the axial direction L. The third bearing B3 rotatably supports the rotor shaft 2. In the present embodiment, the third bearing B3 is disposed so as to support the bearing fitting portion 23 from the outside in the radial direction R. In this example, the third bearing B3 is disposed so as to support the outer peripheral surface of the bearing fitting portion 23 from the outside 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 bearing B3 from the outside in the radial direction R. The third bearing B3 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, outward in the radial direction R from the bearing fitting portion 23 of the rotor shaft 2, so as to overlap with the bearing fitting portion 23 as viewed in the radial direction R.

[0058] The first counter shaft 411 is formed to extend along the second axis X2. In this embodiment, the first counter shaft 411 is rotatably supported with respect to the case 9 by a first counter bearing B11 and a second counter bearing B12.

[0059] In this embodiment, the first counter bearing B11 is disposed on the first axial side L1 with respect to the second gear 4B. In the example shown in Fig. 1, the first counter bearing B11 is disposed on the inner side in the radial direction R with respect to the second axis X2 with respect to the second gear 4B.

[0060] In this embodiment, the first counter bearing B11 is disposed so as to support the outer peripheral surface of the first counter shaft 411 from the outside in the radial direction R. In the example shown in FIG. 1 , the partition wall 91 of the case 9 has a first counter bearing support 91b. The first counter bearing support 91b is formed in a cylindrical shape that protrudes toward the second axial side L2, further inward in the radial direction R than the second gear 4B. The first counter bearing B11 is disposed between the inner peripheral surface of the first counter bearing support 91b and the outer peripheral surface of the first counter shaft 411.

[0061] In this embodiment, the second counter bearing B12 is disposed on the second axial side L2 relative to the third gear 4C. In this embodiment, the second counter bearing B12 is disposed so as to support the outer peripheral surface of the first counter shaft 411 from the outside in the radial direction R. In the example shown in FIG. 1 , the case 9 includes a second counter bearing support portion 94c. The second counter bearing support portion 94c is formed on the intermediate wall portion 94. The second counter bearing support portion 94c is formed in a cylindrical shape having an axis along the axial direction L and is disposed on the second axial side L2 relative to the third gear 4C so as to be spaced apart from the third gear 4C. As a result, the second counter bearing support portion 94c is formed in a cylindrical shape that is outward of the first counter shaft 411 in the radial direction R and overlaps with the first counter shaft 411 as viewed in the radial direction R. The second counter bearing B12 is disposed between the inner peripheral surface of the second counter bearing support portion 94c and the outer peripheral surface of the first counter shaft 411. Thus, in this embodiment, the second counter bearing B12 is disposed on the second axial side L2 relative to the second bearing B2.

[0062] The second counter shaft 421 is formed to extend along the third axis X3. In this embodiment, the second counter shaft 421 is rotatably supported with respect to the case 9 by a third counter bearing B13 and a fourth counter bearing B14.

[0063] In this embodiment, the third counter bearing B13 is disposed on the first axial side L1 with respect to the fourth gear 4D. In the example shown in Fig. 1, the third counter bearing B13 is disposed on the inner side in the radial direction R with respect to the fourth gear 4D, the third axis X3 being the reference point.

[0064] In this embodiment, the third counter bearing B13 is disposed so as to support the outer peripheral surface of the second counter shaft 421 from the outside in the radial direction R. In the example shown in FIG. 1 , the case 9 includes a third counter bearing support portion 94d. The third counter bearing support portion 94d is formed on the intermediate wall portion 94. The third counter bearing support portion 94d is formed in a cylindrical shape that protrudes toward the second axial side L2, more inward in the radial direction R than the fourth gear 4D. The third counter bearing B13 is disposed between the inner peripheral surface of the third counter bearing support portion 94d and the outer peripheral surface of the second counter shaft 421.

[0065] In this embodiment, the fourth counter bearing B14 is disposed on the second axial side L2 relative to the fifth gear 4E. In this embodiment, the fourth counter bearing B14 is disposed so as to support the outer peripheral surface of the second counter shaft 421 from the outside in the radial direction R. In the example shown in FIG. 1 , the case 9 has a fourth counter bearing support 93d. The fourth counter bearing support 93d is formed on the second side wall portion 93b. The fourth counter bearing support 93d is formed in a cylindrical shape having an axis along the axial direction L and is disposed on the second axial side L2 relative to the fifth gear 4E so as to be spaced apart from the fifth gear 4E. As a result, the fourth counter bearing support 93d is formed in a cylindrical shape that is located outside the second counter shaft 421 in the radial direction R and overlaps with the second counter shaft 421 as viewed in the radial direction R. A fourth counter bearing B14 is disposed between the inner peripheral surface of the fourth counter bearing support portion 93d and the outer peripheral surface of the second counter shaft 421.

[0066] In this embodiment, the differential gear mechanism 5 is rotatably supported with respect to the case 9 by a first differential bearing B21 and a second differential bearing B22. In the example shown in FIG. 1 , a differential input member 51 is rotatably supported with respect to the case 9 by the first differential bearing B21 and the second differential bearing B22.

[0067] In the present embodiment, the first differential bearing B21 is disposed so as to support the end of the differential input member 51 on the first axial side L1 from the outside in the radial direction R. In the example shown in FIG. 1 , the case 9 includes a first differential bearing support portion 94b. The first differential bearing support portion 94b is formed on the intermediate wall portion 94. The first differential bearing support portion 94b is formed in a cylindrical shape having an axis along the axial direction L. The first differential bearing support portion 94b is disposed outward in the radial direction R from the end of the differential input member 51 on the first axial side L1, so as to overlap with the end of the differential input member 51 on the first axial side L1 as viewed in the radial direction R. The first differential bearing B21 is disposed between the inner circumferential surface of the first differential bearing support portion 94b and the outer circumferential surface of the end of the differential input member 51 on the first axial side L1.

[0068] In the present embodiment, the second differential bearing B22 is disposed so as to support the end portion of the differential input member 51 on the second axial side L2 from the outside in the radial direction R. In the example shown in FIG. 1 , the second side wall portion 93b of the case 9 is provided with a second differential bearing support portion 93c. The second differential bearing support portion 93c is formed in a cylindrical shape having an axis along the axial direction L. The second differential bearing support portion 93c is disposed outward in the radial direction R from the end portion of the differential input member 51 on the second axial side L2, so as to overlap with the end portion of the differential input member 51 on the second axial side L2 as viewed in the radial direction R. The second differential bearing B22 is disposed between the inner circumferential surface of the second differential bearing support portion 93c and the outer circumferential surface of the end portion of the differential input member 51 on the second axial side L2.

[0069] 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 WH, so as to rotate integrally therewith. In the example shown in FIG. 1 , each of the pair of output members 3 is formed in a cylindrical shape with the first axis X1 as its axis. The drive shaft DS is disposed radially inward of each of the pair of output members 3 in the radial direction R, and the pair of output members 3 are connected to each other by spline engagement.

[0070] The vehicle drive device 100 of this embodiment includes a supply mechanism 7 that supplies cooled oil to various locations within the case 9. The supply mechanism 7 will be described below with reference to FIG.

[0071] The supply mechanism 7 includes an oil pump 71 that circulates oil within the case 9 and an oil cooler 72 that cools the oil circulated by the oil pump 71. In this embodiment, the oil pump 71 draws oil from the case 9 and discharges it toward various locations within the case 9. The oil pump 71 includes, for example, a gear pump or a vane pump. In this embodiment, a suction port (not shown) through which the oil pump 71 draws oil is immersed in oil stored in a reservoir 73. Meanwhile, the discharge port of the oil pump 71 is connected to an oil passage 74 formed in the case 9. The oil passage 74 leads to locations where the oil is needed. The oil discharged from the oil pump 71 passes through the oil passage 74 and reaches each mechanical element. The oil discharged from the oil pump 71 is used, for example, to cool the rotating electric machine 1 and lubricate each mechanical element within the case 9. Here, each mechanical element includes a gear and a bearing. The oil cooler 72 of this embodiment exchanges heat between the oil discharged from the oil pump 71 and a refrigerant, which will be described later. In the example shown in Fig. 4, the oil cooler 72 includes a water-cooled heat exchanger that exchanges heat between the oil and cooling water. In this embodiment, the oil cooler 72 is housed in the case 9.

[0072] In the present embodiment, at least one of the first counter gear mechanism 41 and the second counter gear mechanism 42 is disposed so as to overlap with at least one of the oil pump 71 and the oil cooler 72 as viewed in the axial direction L. In the example shown in FIG. 4 , the oil pump 71 overlaps with the second counter gear mechanism 42 as viewed in the axial direction L. The oil cooler 72 overlaps with both the first counter gear mechanism 41 and the second counter gear mechanism 42 as viewed in the axial direction L.

[0073] The following describes the cooling mechanism 8 for cooling the rotating electric machine 1 and the inverter unit 6. The cooling mechanism 8 circulates a refrigerant inside the case 9, the rotating electric machine 1, or the inverter unit 6. The refrigerant may be a liquid refrigerant such as cooling water, or the outside air outside the case 9. Such a refrigerant exchanges heat with the rotating electric machine 1 and the inverter unit 6. This cools the rotating electric machine 1 and the inverter unit 6. In the example shown in FIG. 4 , a liquid refrigerant exchanges heat with the rotating electric machine 1 and the inverter unit 6.

[0074] The cooling mechanism 8 of this embodiment includes a first heat exchanger 81, a reservoir 73, a second heat exchanger 82, and a refrigerant flow path 80. The first heat exchanger 81 exchanges heat between the inverter unit 6 and the refrigerant. The reservoir 73 is provided in the lower part of the case 9. Oil is stored in the reservoir 73. The second heat exchanger 82 exchanges heat between the oil stored in the reservoir 73 and the refrigerant. The refrigerant flow path 80 is provided in the case 9. The refrigerant flow path 80 is configured so that the refrigerant flows through the first heat exchanger 81, the oil cooler 72, and the second heat exchanger 82 in this order. In this embodiment, the oil cooler 72 exchanges heat between the oil and the refrigerant.

[0075] The refrigerant flow path 80 includes a first refrigerant flow path 80A and a second refrigerant flow path 80B. The first refrigerant flow path 80A connects the first heat exchanger 81 and the oil cooler 72. The second refrigerant flow path 80B connects the oil cooler 72 and the second heat exchanger 82. In the example shown in FIG. 4 , the first refrigerant flow path 80A and the second refrigerant flow path 80B are formed inside the wall of the case 9. Because the first refrigerant flow path 80A and the second refrigerant flow path 80B are formed inside the wall of the case 9, intermediate hoses that are required in an externally mounted structure are not required, making it easier to form the entire vehicle drive device 100 into a compact configuration.

[0076] In the present embodiment, the refrigerant flow path 80 further includes a supply flow path 80C for supplying the refrigerant to the inverter unit 6 and a discharge flow path 80D for discharging the refrigerant supplied to the second heat exchanger 82. The supply flow path 80C communicates from the outside to the inside of the third housing portion A3. The discharge flow path 80D communicates between the inside of the second heat exchanger 82 and the outside. In the example shown in FIG. 4 , the discharge flow path 80D is a pipe for flowing the refrigerant inside the case 9 to the outside of the case 9. Note that in the example shown in FIG. 4 , the supply flow path 80C and the discharge flow path 80D communicate between the inside and outside of the case 9 so that the refrigerant can also circulate outside the case 9. However, the refrigerant flow path 80 may be configured to flow the refrigerant only inside the case 9. In this case, the refrigerant flow path 80 is formed only inside the case 9.

[0077] In this embodiment, the first heat exchanger 81 includes a flow path (e.g., a water channel) formed in the inverter unit 6 housed in the third housing portion A3. The first heat exchanger 81 is formed in the inverter unit 6 so that a refrigerant (e.g., cooling water) flows along a heat sink thermally connected to a plurality of switching elements that constitute, for example, an inverter circuit (not shown). This allows the switching elements, which generate a relatively large amount of heat while the vehicle is running, to be efficiently cooled.

[0078] In the present embodiment, the second heat exchanger 82 is disposed in parallel to the reservoir 73 within the case 9. The refrigerant flowing through the second heat exchanger 82 cools the oil stored in the reservoir 73 through heat exchange within the case 9. In the example shown in Fig. 4, the second heat exchanger 82 is disposed in the first storage section A1. The second heat exchanger 82 is disposed in the lower part of the first storage section A1, in contact with the reservoir 73 across a wall so that the oil stored in the reservoir 73 and the refrigerant flowing through the second heat exchanger 82 do not mix.

[0079] In this embodiment, the first refrigerant flow path 80A is arranged in a position overlapping with at least one of the first counter gear mechanism 41 and the second counter gear mechanism 42, as viewed in the axial direction L. Furthermore, the second refrigerant flow path 80B is arranged in a position overlapping with at least the other of the first counter gear mechanism 41 and the second counter gear mechanism 42, as viewed in the axial direction L. In this embodiment, the first refrigerant flow path 80A overlaps with the first counter gear mechanism 41, as viewed in the axial direction L. Furthermore, the second refrigerant flow path 80B overlaps with the second counter gear mechanism 42, as viewed in the axial direction L.

[0080] Other Embodiments (1) In the above embodiment, the bevel gear type differential gear mechanism 5 has been described as an example. 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.

[0081] (2) In the above embodiment, the entire first counter gear mechanism 41 is described as being disposed on one side in the width direction W with respect to the first axis X1. However, a portion of the first counter gear mechanism 41 may be disposed on the other side in the width direction W with respect to the first axis X1. Similarly, in the above embodiment, the entire second counter gear mechanism 42 is described as being disposed on one side in the width direction W with respect to the first axis X1. However, a portion of the second counter gear mechanism 42 may be disposed on the other side in the width direction W with respect to the first axis X1.

[0082] (3) In the above embodiment, the first axis X1, the second axis X2, and the third axis X3 are described as being parallel to one another. However, some of the axes may be in a positional relationship in which they intersect with other axes at an intersection. For example, the first axis X1 may be in a positional relationship in which it intersects with the second axis X2 at an intersection.

[0083] (4) In the above embodiment, the inverter unit 6 is described as being arranged to overlap both the rotating electric machine 1 and the differential input gear 4F when viewed in the axial direction L. However, the inverter unit 6 may overlap only the rotating electric machine 1 when viewed in the axial direction L. Conversely, the inverter unit 6 may overlap only the differential input gear 4F when viewed in the axial direction L.

[0084] (5) In the above embodiment, the oil discharged from the oil pump 71 is described as cooling the rotating electric machine 1 and the various mechanical elements in the case 9. However, the oil discharged from the oil pump 71 may be used solely for cooling the rotating electric machine 1. In this case, supplying lubricating oil to lubricate the gear mechanism and bearings includes immersing part of the gear mechanism, etc. in the lubricating oil and scooping up the lubricating oil through the rotation of the gear mechanism, etc. Conversely, the oil discharged from the oil pump 71 may be used solely for lubricating the various mechanical elements. In this case, the cooling structure of the rotating electric machine 1 is a water-cooled type or an air-cooled type.

[0085] (6) In the above embodiment, the oil passage 74 is described as being formed in the case 9. However, the oil passage 74 may be formed by a pipe or the like that is a separate member from the case 9. In this case, there is no need to form the oil passage 74 in the case 9, which simplifies the structure of the case 9. Furthermore, the oil passage 74 may be formed by combining the case 9 with the pipe.

[0086] (7) The oil pump 71 may be driven by either a mechanical or an electric method. The mechanical oil pump 71 may be driven by being connected to a drive source via a transmission element such as a gear mechanism. Examples of such a drive source include the rotating electric machine 1 and an internal combustion engine. In addition, if the oil pump 71 is an electric oil pump, the oil pump 71 may be driven by being connected to a motor that is provided separately from the rotating electric machine 1.

[0087] (8) In the above embodiment, the oil pump 71 has been described as overlapping with the second counter gear mechanism 42 as viewed in the axial direction L. However, the oil pump 71 may also overlap with the first counter gear mechanism 41 as viewed in the axial direction L. Furthermore, the oil pump 71 may also overlap with both the first counter gear mechanism 41 and the second counter gear mechanism 42 as viewed in the axial direction L. Furthermore, the oil cooler 72 has been described as overlapping with both the first counter gear mechanism 41 and the second counter gear mechanism 42 as viewed in the axial direction L. However, the oil cooler 72 may also overlap with either the first counter gear mechanism 41 or the second counter gear mechanism 42 as viewed in the axial direction L.

[0088] (9) In the above embodiment, the oil cooler 72 is described as including a water-cooled type. Alternatively, the oil cooler 72 may be an air-cooled heat exchanger that exchanges heat between oil and air. This air may be, for example, air outside the case 9. The oil cooler 72 also includes a heat exchanger that exchanges heat between oil and a refrigerant used in an air conditioning device.

[0089] (10) In the above embodiment, it has been described that the first refrigerant flow path 80A overlaps with the first counter gear mechanism 41 when viewed in the axial direction L, and the second refrigerant flow path 80B overlaps with the second counter gear mechanism 42 when viewed in the axial direction L. However, the first refrigerant flow path 80A may also overlap with the second counter gear mechanism 42. Furthermore, the first refrigerant flow path 80A may also overlap with both the first counter gear mechanism 41 and the second counter gear mechanism 42 when viewed in the axial direction L. Similarly, the second refrigerant flow path 80B may also overlap with the first counter gear mechanism 41. Furthermore, the second refrigerant flow path 80B may also overlap with both the first counter gear mechanism 41 and the second counter gear mechanism 42 when viewed in the axial direction L.

[0090] (11) In the above embodiment, the first refrigerant flow path 80A is described as being formed inside the wall of the case 9. However, the first refrigerant flow path 80A may be formed by a pipe that is a separate member from the case 9. In this case, the pipe may be provided either outside the case 9 or inside the case 9. Similarly, the second refrigerant flow path 80B may also be formed by a pipe as described above.

[0091] (12) 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.

[0092] Summary of the Present Embodiment The following provides a summary of the embodiment relating to the vehicle drive device (100) described above.

[0093] The vehicle drive device (100) includes a rotating electric machine (1) having a rotor (12), a pair of output members (3) each drivingly connected to a wheel (WH), a speed reduction mechanism (4) that reduces the rotation of the rotor (12), and a differential gear mechanism (5) that includes a differential input member (51) and distributes the rotation transmitted from the speed reduction mechanism (4) to the differential input member (51) to the pair of output members (3), wherein the rotor (12), the pair of output members (3), and the differential gear mechanism (5) are arranged on a first axis (X1), and the speed reduction mechanism (4) is arranged on the first axis (X1) and includes a first gear (4A) that is connected to the rotor (12) so as to rotate integrally with the rotor (12), and a second gear (4A) that is connected to the first gear (4A) so as to rotate integrally with the rotor (12). a first counter gear mechanism (41) including a second gear (4B) meshing with the third gear (4C) and a third gear (4C) connected to rotate integrally with the second gear (4B), and disposed on a second axis (X2) separate from the first axis (X1); a second counter gear mechanism (42) including a fourth gear (4D) meshing with the third gear (4C) and a fifth gear (4E) connected to rotate integrally with the fourth gear (4D), and disposed on a third axis (X3) separate from the first axis (X1) and the second axis (X2); and a sixth gear (4F) disposed on the first axis (X1), meshing with the fifth gear (4E), and connected to rotate integrally with the differential input member (51).

[0094] According to this configuration, the rotation of the rotor (12) can be reduced in three places before being transmitted to the differential gear mechanism (5): the meshing portion between the first gear (4A) and the second gear (4B), the meshing portion between the third gear (4C) and the fourth gear (4D), and the meshing portion between the fifth gear (4E) and the sixth gear (4F). Therefore, compared to a configuration having only one counter gear mechanism between the rotor (12) and the differential gear mechanism (5), it is easier to reduce the diameters of the multiple gears while ensuring a sufficient reduction ratio. Therefore, it is easier to reduce the overall size of the vehicle drive device (100). Furthermore, according to this configuration, the reduction mechanism (4) can be configured using a relatively simple combination of gears, which makes it easier to improve transmission efficiency and reduce manufacturing costs compared to a configuration using a planetary gear mechanism as the reduction mechanism (4).

[0095] Here, the first axis (X1), the second axis (X2), and the third axis (X3) are parallel to each other, the direction along the first axis (X1) is defined as the axial direction (L), and the direction perpendicular to the first axis (X1) when viewed in the up-down direction is defined as the width direction (W), and both the second axis (X2) and the third axis (X3) are arranged on one side of the first axis (X1) in the width direction (W), and both the first counter gear mechanism (41) and the second counter gear mechanism (42) are arranged so as to overlap with the rotating electric machine (1) when viewed in the axial direction (L), and it is preferable that the first counter gear mechanism (41) and the second counter gear mechanism (42) are arranged so as to overlap with each other when viewed in the axial direction (L).

[0096] According to this configuration, it is easy to keep the size of the vehicle drive device (100) small when viewed in the axial direction (L).

[0097] Furthermore, 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 axial first side (L1), and the other side of the axial direction (L) is defined as the axial second side (L2), and the rotor (12), the first gear (4A), and the differential gear mechanism (5) are arranged on the first axis (X1) in the order described above from the axial first side (L1) to the axial second side (L2), and the third gear (4C) and the fourth gear (4D) is arranged on the second axial side (L2) of the first gear (4A) and the second gear (4B), the fifth gear (4E) and the sixth gear (4F) are arranged on the second axial side (L2) of the third gear (4C) and the fourth gear (4D), and it is preferable that the axial (L) arrangement area of ​​the differential gear mechanism (5) overlaps with the axial (L) arrangement area of ​​the third gear (4C) and the fourth gear (4D).

[0098] According to this configuration, the rotor (12) is disposed on the first axial side (L1) relative to the first gear (4A), the differential gear mechanism (5) is disposed on the second axial side (L2) relative to the first gear (4A), the third gear (4C) and the fourth gear (4D) are disposed on the second axial side (L2) relative to the first gear (4A) and the second gear (4B), the fifth gear (4E) and the sixth gear (4F) are disposed on the second axial side (L2) relative to the third gear (4C) and the fourth gear (4D), and the sixth gear (4F) is connected to the differential input member (51) so as to rotate integrally with the differential input member (51). Therefore, the driving force can be transmitted from the rotor (12) to the differential input member (51) from the first axial side (L1) to the second axial side (L2). This facilitates simplifying the gear arrangement of the reduction mechanism (4). Furthermore, according to this configuration, the axial (L) arrangement area of ​​the differential gear mechanism (5) overlaps with the axial (L) arrangement areas of the third gear (4C) and the fourth gear (4D), making it easier to reduce the axial (L) dimension of the vehicle drive device (100) compared to when these do not overlap.

[0099] Furthermore, it is preferable that the inverter unit (6) for driving and controlling the rotating electric machine (1) is further provided, and that the direction along the first axis (X1) is defined as the axial direction (L), and that at least a portion of the inverter unit (6) is located between the rotating electric machine (1) and the sixth gear (4F) in the axial direction (L), and is arranged so as to overlap with both the rotating electric machine (1) and the sixth gear (4F) when viewed in the axial direction (L) along the axial direction (L).

[0100] According to this configuration, when the vehicle drive device (100) includes the inverter unit (6), both the rotating electric machine (1) and the sixth gear (4F) are arranged so as to overlap with the inverter unit (6) in the axial direction (L), which makes it easier to reduce the size of the vehicle drive device (100) in the axial direction (L) compared to when they are arranged so as not to overlap. Furthermore, at least a portion of the inverter unit (6) can be arranged by utilizing the space generated between the rotating electric machine (1) and the sixth gear (4F) in the axial direction (L). Therefore, it is easier to reduce the size of the vehicle drive device (100).

[0101] The rotating electric machine further includes a case (9) that houses the rotating electric machine (1), the reduction mechanism (4), and the differential gear mechanism (5), an oil pump (71) that sucks and circulates oil in the case (9), and an oil cooler (72) that cools the oil circulated by the oil pump (71), and it is preferable that the direction along the first axis (X1) is defined as an axial direction (L), and that at least one of the first counter gear mechanism (41) and the second counter gear mechanism (42) is arranged so as to overlap with at least one of the oil pump (71) and the oil cooler (72) when viewed in the axial direction (L) along the axial direction (L).

[0102] According to this configuration, at least one of the first counter gear mechanism (41) and the second counter gear mechanism (42) is arranged so as to overlap with at least one of the oil pump (71) and the oil cooler (72) when viewed in the axial direction (L), and therefore, compared to when these are arranged so as not to overlap, it is easier to keep the size of the vehicle drive device (100) small when viewed in the axial direction (L).

[0103] The oil cooler further includes an inverter unit (6) for driving and controlling the rotating electric machine (1), a first heat exchange section (81) for exchanging heat between the inverter unit (6) and a refrigerant, a reservoir section (73) provided in the lower part of the case (9) for storing the oil, and a second heat exchange section (82) for exchanging heat between the oil stored in the reservoir section (73) and the refrigerant, wherein the oil cooler (72) exchanges heat between the oil and the refrigerant, and the case (9) is provided with a refrigerant flow path (80) configured so that the refrigerant flows through the first heat exchange section (81), the oil cooler (72), and the second heat exchange section (82) in this order, The refrigerant flow path (80) includes a first refrigerant flow path (80A) that connects the first heat exchange section (81) and the oil cooler (72), and a second refrigerant flow path (80B) that connects the oil cooler (72) and the second heat exchange section (82), and it is preferable that, as viewed in the axial direction (L), the first refrigerant flow path (80A) is arranged at a position that overlaps with at least one of the first counter gear mechanism (41) and the second counter gear mechanism (42), and that, as viewed in the axial direction (L), the second refrigerant flow path (80B) is arranged at a position that overlaps with at least the other of the first counter gear mechanism (41) and the second counter gear mechanism (42).

[0104] According to this configuration, at least a portion of the refrigerant flow path (80) can be arranged by utilizing the space overlapping with the first counter gear mechanism (41) and the second counter gear mechanism (42) in the axial direction (L), which makes it easier to reduce the overall size of the vehicle drive device (100).

[0105] The rotating electric machine further includes a case (9) that houses the rotating electric machine (1), the reduction mechanism (4), and the differential gear mechanism (5), with the direction along the front first axis (X1) being the axial direction (L), one side of the axial direction (L) being a first axial side (L1), and the other side of the axial direction (L) being a second axial side (L2), and the case (9) includes an intermediate wall portion (94) that supports at least one of the rotor (12), the reduction mechanism (4), and the differential gear mechanism (5) inside the case (9), and the intermediate wall portion (94) includes a portion that is arranged on the second axial side (L2) with respect to the third gear (4C) and a portion that is arranged on the first axial side (L1) with respect to the fourth gear (4D), and the third gear (4C) and the fourth gear (4D) mesh with each other while passing through the intermediate wall portion (94).

[0106] According to this configuration, the rotor (12), the reduction mechanism (4), and the differential gear mechanism (5) supported by the intermediate wall portion (94) are supported at an intermediate position along the axial direction (L) inside the case (9), which facilitates downsizing in the axial direction (L). In addition, since it is not necessary to provide an engagement portion between the third gear (4C) and the fourth gear (4D) at a position that bypasses the intermediate wall portion (94) in order to support at least one of the rotor (12), the reduction mechanism (4), and the differential gear mechanism (5) on the intermediate wall portion (94), it is easy to achieve downsizing of the entire vehicle drive device (100).

[0107] 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.

[0108] 100: Vehicle drive device, 1: Rotating electric machine, 12: Rotor, 3: Output member, 4: Reduction mechanism, 4A: First gear, 41: First counter gear mechanism, 4B: Second gear, 4C: Third gear, 42: Second counter gear mechanism, 4D: Fourth gear, 4E: Fifth gear, 4F: Differential input gear (sixth gear), 5: Differential gear mechanism, 51: Differential input member, 6: Inverter unit 71: oil pump, 72: oil cooler, 73: reservoir, 81: first heat exchanger, 82: second heat exchanger, 80: refrigerant flow path, 80A: first refrigerant flow path, 80B: second refrigerant flow path, 9: case, 94: intermediate wall, L: axial direction, L1: first axial side, L2: second axial side, R: radial direction, WH: wheel, X1: first axis, X2: second axis, X3: third axis

Claims

1. A vehicle drive device comprising: a rotating electric machine having a rotor; a pair of output members, each of which is drivingly connected to wheels; a speed reduction mechanism for reducing the rotation of the rotor; and 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, wherein the rotor, the pair of output members, and the differential gear mechanism are arranged on a first axis, and the speed reduction mechanism comprises: a first gear arranged on the first axis and connected to rotate integrally with the rotor; a second gear meshing with the first gear, and a third gear connected to rotate integrally with the second gear, and a first counter gear mechanism arranged on a second axis separate from the first axis; a second counter gear mechanism arranged on a third axis separate from the first axis and the second axis, and a sixth gear disposed on the first axis, meshing with the fifth gear and connected to rotate integrally with the differential input member.

2. The first shaft center, the second shaft center, and the third shaft center are parallel to each other, the direction along the first shaft center is the axial direction, and the direction perpendicular to the first shaft center when viewed in the up-down direction is the width direction, and both the second shaft center and the third shaft center are arranged on one side of the first shaft center in the width direction, both the first counter gear mechanism and the second counter gear mechanism are arranged so as to overlap with the rotating electric machine when viewed in the axial direction, and the first counter gear mechanism and the second counter gear mechanism are arranged so as to overlap with each other when viewed in the axial direction. A vehicle drive device as described in claim 1.

3. A vehicle drive device as described in claim 1 or 2, wherein the direction along the first axis is the axial direction, one side in the axial direction is the axial first side, and the other side in the axial direction is the axial second side, the rotor, the first gear, and the differential gear mechanism are arranged on the first axis in the order listed from the axial first side to the axial second side, the third gear and the fourth gear are arranged on the axial second side of the first gear and the second gear, the fifth gear and the sixth gear are arranged on the axial second side of the third gear and the fourth gear, and the axial arrangement area of ​​the differential gear mechanism overlaps with the axial arrangement area of ​​the third gear and the fourth gear.

4. A vehicle drive device as described in claim 3, further comprising an inverter unit for driving and controlling the rotating electric machine, wherein the direction along the first axis is the axial direction, and at least a portion of the inverter unit is between the rotating electric machine and the sixth gear, and is positioned so as to overlap with both the rotating electric machine and the sixth gear when viewed in the axial direction along the axial direction.

5. A vehicle drive device as described in claim 1 or 2, further comprising: a case that houses the rotating electric machine, the reduction mechanism, and the differential gear mechanism; an oil pump that draws in and circulates oil in the case; and an oil cooler that cools the oil circulated by the oil pump, wherein the direction along the first axis is the axial direction, and at least one of the first counter gear mechanism and the second counter gear mechanism are arranged so as to overlap with at least one of the oil pump and the oil cooler when viewed in the axial direction along the axial direction.

6. A vehicle drive device as claimed in claim 5, further comprising: an inverter unit for controlling the drive of the rotating electric machine; a first heat exchange section which exchanges heat between the inverter unit and a refrigerant; a storage section provided in a lower part of the case in which the oil is stored; and a second heat exchange section which exchanges heat between the oil stored in the storage section and the refrigerant, wherein the oil cooler exchanges heat between the oil and the refrigerant, and the case is provided with a refrigerant flow path configured so that the refrigerant flows in the order of the first heat exchange section, the oil cooler, and the second heat exchange section, the refrigerant flow path comprising: a first refrigerant flow path connecting the first heat exchange section and the oil cooler; and a second refrigerant flow path connecting the oil cooler and the second heat exchange section, wherein the first refrigerant flow path is positioned so as to overlap with at least one of the first counter gear mechanism and the second counter gear mechanism when viewed in the axial direction, and the second refrigerant flow path is positioned so as to overlap with at least the other of the first counter gear mechanism and the second counter gear mechanism when viewed in the axial direction.

7. A vehicle drive device as described in claim 1 or 2, further comprising a case that houses the rotating electric machine, the reduction mechanism, and the differential gear mechanism, with the direction along the first axis being the axial direction, one side in the axial direction being the axial first side, and the other side in the axial direction being the axial second side, wherein the case has an intermediate wall portion that supports at least one of the rotor, the reduction mechanism, and the differential gear mechanism inside the case, and the intermediate wall portion has a portion that is arranged on the axial second side with respect to the third gear and a portion that is arranged on the axial first side with respect to the fourth gear, and the third gear and the fourth gear mesh with each other while passing through the intermediate wall portion.

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