Vehicle drive systems

Abstract

Disclosed is a drive device for a vehicle comprising a rotary electric machine, a transmission mechanism, an inverter device, a case having a first case portion that houses the rotary electric machine, and a rotor shaft to which a rotor is fixed, the rotary electric machine and a pair of output members have a two-shaft structure, the transmission mechanism is provided with an output gear that is drivingly connected to at least one of the pair of output members coaxially with the pair of output members, the output gear is disposed so as to overlap with each of the rotary electric machine and the inverter device as viewed in the axial direction, the inverter device is disposed so as to overlap with a first output member, which is one of the pair of output members, as viewed in the vertical direction, the first output member is disposed so as to overlap with the axial center of the rotor shaft as viewed in the horizontal direction, and the inverter device is disposed at a position below the uppermost position of the first case portion in a second direction.

Description

Technical Field

[0001] The present disclosure relates to a vehicle drive device.

Background Art

[0002] By arranging an output member drivingly connected to a wheel offset in the vertical direction without overlapping in the horizontal direction with respect to a rotor shaft to which a rotor of a rotating electric machine is fixed, an inverter device is arranged using a space on one horizontal side and above the rotating electric machine, which is a space lower than the highest position in the case (see, for example, FIG. 4 of Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the prior art as described above has a layout in which an output member drivingly connected to a wheel is arranged offset in the vertical direction without overlapping in the horizontal direction with respect to the rotor shaft, and it is difficult to reduce the vertical dimensions of the entire vehicle drive device.

[0005] Therefore, on one aspect, the present disclosure aims to reduce the vertical dimensions of the entire vehicle drive device.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, a rotating electric machine having a rotor and a stator, a first output member which is one of a pair of output members respectively drivingly connected to a pair of wheels, A transmission mechanism for transmitting driving force between the rotating electric machine and a pair of output members, An inverter device that receives power from a battery and supplies power to the rotating electric machine, A case having a first case section for housing the rotating electric machine, a second case section for housing the transmission mechanism, and a third case section for housing the inverter device, The rotor is fixed so as not to rotate and comprises a rotor shaft supported by the case, The rotating electric machine and the pair of output members are arranged on two axes that are parallel to each other. The transmission mechanism includes an output gear, which is driven and connected to at least one of the pair of output members, coaxially with the pair of output members. The output gear is arranged so as to overlap with the rotating electric machine and the inverter device in an axial view along the axial direction. The inverter device is arranged so as to overlap with the transmission mechanism or the first output member when viewed in the vertical direction. A vehicle drive system is provided, wherein the pair of output members are arranged so as to overlap with the axis of the rotor shaft when viewed in the direction along the longitudinal direction of the vehicle, and the inverter device is arranged below the uppermost position of the first case portion in the vertical direction. [Effects of the Invention]

[0007] In one respect, this disclosure makes it possible to reduce the overall vertical size of the vehicle drive system. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic top view diagram showing the mounting configuration of the vehicle's drive system. [Figure 2] This is a cross-sectional view of the main components of a vehicle's drive system. [Figure 2A] This is a skeleton diagram showing a vehicle drive system. [Figure 3] This is a schematic three-view drawing showing a vehicle drive system according to Example 1. [Figure 4] This figure schematically shows a vehicle drive system according to Example 1 in an axial view. [Figure 5] This figure schematically shows a vehicle drive system according to Embodiment 1, viewed from the first axial side. [Figure 6] This is an explanatory diagram illustrating a modified example of Figure 5. [Figure 7] This diagram schematically shows the interior of the vehicle drive unit according to Embodiment 1, viewed from the first axial side. [Figure 8] This is a two-view diagram schematically showing a vehicle drive system according to Example 2. [Figure 9] This figure schematically shows the vehicle drive system according to Embodiment 2, viewed from a direction perpendicular to the two directions of the two-view drawing in Figure 8. [Figure 10] This is an explanatory diagram illustrating a modified example of Figure 9. [Figure 11] This figure schematically shows a vehicle drive system according to Embodiment 2 in an axial view as seen from the first axial side. [Figure 12] This diagram schematically shows the interior of the vehicle drive unit according to Embodiment 2, viewed from the first axial side. [Modes for carrying out the invention]

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, some shapes and other details in the drawings may be exaggerated for illustrative purposes.

[0010] In the following description, the vertical direction V (see FIG. 2 etc.) means the vertical direction in the usage state of the vehicle drive device 100, that is, the vertical direction when the vehicle drive device 100 is arranged in the orientation in its usage state. Since the vehicle drive device 100 is mounted on a vehicle VC (see FIG. 1) and used, the vertical direction V is the vertical direction in the state where the vehicle drive device 100 is mounted on the vehicle VC (hereinafter referred to as the "vehicle-mounted state"), more specifically, it coincides with the vertical direction in the vehicle-mounted state where the vehicle VC is stopped on a flat road (a road along a horizontal plane). And the upper side V1 and the lower side V2 mean the upper side and the lower side in this vertical direction V. Also, the directions of the respective members in the following description represent the directions in the state where they are assembled to the vehicle drive device 100. Further, terms related to the dimensions, arrangement directions, arrangement positions, etc. of the respective members are concepts including states having differences due to errors (errors allowable in manufacturing).

[0011] In this specification, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force (synonymous with torque), including 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 with speed change (for example, shafts, gear mechanisms, belts, chains, etc.). Note that the transmission members may include engagement devices (for example, friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0012] In this specification, the "rotating electrical machine" is used as a concept that includes any of a motor (electric motor), a generator (dynamo), and a motor-generator that performs the functions of both a motor and a generator as needed. Further, in this specification, regarding the arrangement of two members, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a partial region where the virtual straight line intersects both of the two members. Also, in this specification, regarding the arrangement of two members, "the arrangement regions in a specific direction overlap" means that at least a part of the arrangement region of the other member in a specific direction is included within the arrangement region of one member in the specific direction.

[0013] FIG. 1 is a schematic top view showing the mounted state of the vehicle drive device 100 in the vehicle VC. FIG. 2 is a cross-sectional view of a main part of the vehicle drive device 100. FIG. 2A is a skeleton view showing the vehicle drive device 1C FIG. 3 is a three-view schematically showing the vehicle drive device 100 according to the present embodiment, and a part is shown in perspective so that the inside can be seen.

[0014] As schematically shown in FIG. 1, the vehicle drive device 100 includes a rotating electrical machine 1, a pair of output members 6 respectively drivingly connected to a pair of vehicle wheels W (see FIG. 1), a transmission mechanism 3 that transmits driving force between the rotating electrical machine 1 and the pair of output members 6, and an inverter device 90 that drives and controls the rotating electrical machine 1. The vehicle drive device 100 further includes a case 2 that houses the rotating electrical machine 1 and the inverter device 90. The case 2 also houses the pair of output members 6 and the transmission mechanism 3.

[0015] One of a pair of output members 6, the first output member 61, is driven and connected to the first wheel W1, one of a pair of wheels W, and the other of the pair of output members 6, the second output member 62, is driven and connected to the second wheel W2, the other of the pair of wheels W. As shown in Figure 1, the vehicle VC on which the vehicle drive unit 100 is mounted includes a first drive shaft 63 that rotates integrally with the first wheel W1 and a second drive shaft 64 that rotates integrally with the second wheel W2. The first drive shaft 63 is connected to the first wheel W1, for example via a constant velocity joint, and the second drive shaft 64 is connected to the second wheel W2, for example via a constant velocity joint. The first output member 61 is connected to the first drive shaft 63 so as to rotate integrally with the first drive shaft 63, and the second output member 62 is connected to the second drive shaft 64 so as to rotate integrally with the second drive shaft 64.

[0016] The vehicle drive system 100 transmits the output torque of the rotating electric machine 1 to a pair of wheels W via a pair of output members 6, thereby driving the vehicle VC on which the vehicle drive system 100 is mounted. In other words, the rotating electric machine 1 is the driving force source for the pair of wheels W. The pair of wheels W are a left and right pair of wheels on the vehicle VC (for example, a left and right pair of front wheels, or a left and right pair of rear wheels). The rotating electric machine 1 may be, for example, an AC rotating electric machine driven by three-phase AC (an example of multi-phase AC). The rotating electric machine 1 is electrically connected to a battery BA (including an energy storage device such as a capacitor) via an inverter device 90 that performs power conversion between DC power and AC power, and is powered by power supplied from the battery BA, or power generated by the inertial force of the vehicle VC is supplied to the energy storage device for storage.

[0017] As shown in Figure 2, the rotating electric machine 1 and the pair of output members 6 are arranged on two parallel axes (specifically, the first axis C1 and the second axis C2). Specifically, the rotating electric machine 1 is positioned on the first axis C1, and the pair of output members 6 are positioned on the second axis C2, which is different from the first axis C1. The first axis C1 and the second axis C2 are axes (virtual axes) that are positioned parallel to each other. The transmission mechanism 3 is provided with an output gear 30 that is driven and connected to at least one of the pair of output members 6, coaxially with the pair of output members 6 (i.e., on the second axis C2).

[0018] As shown in Figure 1, the vehicle drive unit 100 is mounted on the vehicle VC with its axial direction A aligned with the left-right direction of the vehicle. The axial direction A is parallel to the first axis C1 and the second axis C2, in other words, it is the common axial direction between the first axis C1 and the second axis C2. That is, the axial direction A is the direction in which the rotation axis of the rotating electric machine 1 extends, and also the direction in which the rotation axes of the pair of output members 6 extend. Here, one side of the axial direction A is called the axial first side A1, and the other side of the axial direction A (opposite to the axial first side A1 in the axial direction A) is called the axial second side A2. The axial first side A1 is the side in the axial direction A on which the rotating electric machine 1 is positioned relative to the transmission mechanism 3. As shown in Figure 2, the first output member 61 is the output member 6 of the pair of output members 6 that is positioned on the axial first side A1, and the second output member 62 is the output member 6 of the pair of output members 6 that is positioned on the axial second side A2.

[0019] As shown in Figure 1, the vehicle drive unit 100 may be mounted on the vehicle VC with the axial first side A1 on the right side of the vehicle and the axial second side A2 on the left side of the vehicle. In this case, the first wheel W1 to which the first output member 61 is driven is the right wheel, and the second wheel W2 to which the second output member 62 is driven is the left wheel. Figure 1 assumes that the vehicle drive unit 100 is a front-wheel drive system that drives a pair of left and right front wheels. Therefore, in the example shown in Figure 1, the first wheel W1 is the right front wheel, and the second wheel W2 is the left front wheel.

[0020] As shown in Figure 2, the rotating electric machine 1 comprises a rotor 10 and a stator 11. The stator 11 is fixed to the case 2, and the rotor 10 is supported by the case 2 so as to be rotatable relative to the stator 11. The rotating electric machine 1 may be an inner rotor type, in which case the rotor 10 may be positioned radially inward relative to the stator 11, overlapping with the stator 11 in a radial view along the radial direction. Here, the radial direction is the radial direction with respect to the first axis C1, in other words, the radial direction with respect to the rotation axis of the rotating electric machine 1.

[0021] The stator 11 comprises a stator core 12 and coil end portions 13 that protrude from the stator core 12 in the axial direction A. A coil is wound around the stator core 12, and the portion of the coil that protrudes from the stator core 12 in the axial direction A forms the coil end portions 13. The coil end portions 13 are formed on both sides of the stator core 12 in the axial direction A.

[0022] The transmission mechanism 3 includes a reduction mechanism 34 in the power transmission path between the rotating electric machine 1 and the output gear 30. The reduction mechanism 34 is optional and may include a reduction mechanism using a counter gear or a reduction mechanism using planetary gears. In this embodiment, as an example, the reduction mechanism 34 includes a planetary gear mechanism and is arranged coaxially with the rotating electric machine 1. The output gear (carrier) 342 of the reduction mechanism 34 meshes radially with the output gear 30 of the differential gear mechanism 5. Such a vehicle drive system 100 can have a compact configuration consisting of two shafts (first shaft C1 and second shaft C2). In a modified example, the vehicle drive system 100 may have three or more shafts.

[0023] In this embodiment, the reduction mechanism 34 is arranged coaxially with the rotating electric machine 1 (i.e., on the first shaft C1) in a manner that drives and connects it to the rotating electric machine 1. The input member 16 that meshes with the sun gear 341 of the reduction mechanism 34 is connected to the rotor 10 so as to rotate integrally with the rotor 10. In the example shown in Figure 2, the vehicle drive unit 100 includes a rotor shaft 15 to which the rotor 10 is fixed, and the input member 16 is connected to the rotor shaft 15 so as to rotate integrally with the rotor shaft 15. Specifically, the axial first side A1 portion of the input member 16 may be connected (in this case, by spline connection) to the axial second side A2 portion of the rotor shaft 15. In contrast to this configuration, the rotor shaft 15 of the vehicle drive unit 100 can also be configured such that the input member 16 and the rotor shaft 15 are integrally formed as a single piece.

[0024] Furthermore, the transmission mechanism 3 further includes a differential gear mechanism 5. The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to a pair of output members 6. The differential gear mechanism 5 may be arranged coaxially with the pair of output members 6 (i.e., on the second shaft C2). The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to the output gear 30 to the pair of output members 6. That is, the output gear 30 is driven and connected to both of the pair of output members 6 via the differential gear mechanism 5. The differential gear mechanism 5 may be a bevel gear type differential gear mechanism, and the output gear 30 may be connected to the differential case portion 50 of the differential gear mechanism 5 so as to rotate integrally with the differential case portion 50.

[0025] In the example shown in Figure 2, the differential gear mechanism 5 distributes the rotation of the output gear 30 to a first side gear 51 and a second side gear 52. The first side gear 51 rotates integrally with the first output member 61, and the second side gear 52 rotates integrally with the second output member 62. The first side gear 51 may be formed from a separate component from the components constituting the first output member 61 (here, the shaft member), and may be connected to the first output member 61 (here, spline connected) so as to rotate integrally with the first output member 61. At least the portion of the first output member 61 on the axial first side A1 is formed in a cylindrical shape (specifically, a cylindrical shape) extending in the axial direction A, and the first drive shaft 63 (see Figure 1) may be inserted into the interior of the first output member 61 (the space surrounded by the inner circumferential surface) from the axial first side A1. The second output member 62 may also be connected to the second side gear 52. The second output member 62 may also be realized by a second drive shaft 64.

[0026] In this embodiment, the output gear 30 of the differential gear mechanism 5 is preferably located near the axial second side A2 end of the case 2. In this case, the gear (not shown) of the reduction mechanism 34 that meshes with the output gear 30 may be located at the axial second side A2 of the reduction mechanism 34. In this case, the output gear 30 can be positioned closer to the axial second side A2 of the entire vehicle drive unit 100.

[0027] In this embodiment, case 2 includes a motor case section 21, a transmission mechanism case section 22, an output shaft case section 23, and an inverter case section 24 in an integrated form. Here, "integrated form" includes forms where the components are integrated with fastening members such as bolts, or forms where they are integrated by integral molding (for example, casting or aluminizing).

[0028] The motor case section 21 forms a motor housing chamber S1 for housing the rotating electric machine 1, the transmission mechanism case section 22 forms a transmission mechanism housing chamber S2 for housing the transmission mechanism 3, the output shaft case section 23 forms an output shaft housing chamber S3 for housing the first output member 61, and the inverter case section 24 forms an inverter housing chamber S4 for housing the inverter device 90. Note that when we say that the motor case section 21 forms the motor housing chamber S1, we mean that the wall section bordering the motor housing chamber S1 forms the motor case section 21. This also applies to the transmission mechanism housing chamber S2, the output shaft case section 23, and the inverter case section 24.

[0029] In this embodiment, since the output shaft case portion 23 is provided, the first output member 61 can be effectively protected from the external environment (e.g., flying stones) compared to the case where the first output member 61 is provided outside the case 2. In addition, the clearance that needs to be maintained between the first output member 61 and surrounding parts can be reduced.

[0030] Case 2 may be formed by joining multiple components (case components and cover components). Therefore, one case component forming Case 2 may form two or more case components from among the motor case component 21, the transmission mechanism case component 22, the output shaft case component 23, and the inverter case component 24.

[0031] Furthermore, the motor housing chamber S1, transmission mechanism housing chamber S2, output shaft housing chamber S3, and inverter housing chamber S4 formed by case 2 may be completely isolated from each other, partially connected, or shared in a manner without boundaries. For example, the motor housing chamber S1 and the output shaft housing chamber S3 may be shared in a manner without partition walls separating them. In this case, the rotating electric machine 1 and the first output member 61 will be housed in a common housing chamber formed by case 2 (specifically, the motor housing chamber S1 and the output shaft housing chamber S3).

[0032] In the following description, Case 2 is assumed to be formed by joining together a case member 200, a motor cover member 201, a differential cover member 202, and an inverter cover member 203, as an example. The joining method may be fastening with bolts or the like.

[0033] The case member 200 may be formed from a single piece of material (for example, a single piece of material made by die-casting). In this case, the motor housing chamber S1 and the transmission mechanism housing chamber S2 may be separated by a single partition wall 26.

[0034] The case member 200 has an opening in the axial direction A on the first axial side A1 and an opening in the axial direction A on the second axial side A2.

[0035] The motor cover member 201 is provided to cover the opening on the first axial side A1 of the case member 200 (i.e., the opening on the first axial side A1 of the motor housing chamber S1). The motor cover member 201 may be formed as a single piece. The motor cover member 201 may be joined to the end face (joint surface) of the first axial side A1 of the case member 200. In this case, the joint surface (matting surface) 221 between the motor cover member 201 and the case member 200 may extend in a plane perpendicular to the axial direction A.

[0036] The differential cover member 202 is provided to cover the axial second side A2 opening of the case member 200 (i.e., the axial second side A2 opening of the transmission mechanism housing chamber S2). The differential cover member 202 may be formed as a single piece. The differential cover member 202 may be joined to the end face (joint surface) of the axial second side A2 of the case member 200. In this case, the joint surface (matting surface) 222 between the differential cover member 202 and the case member 200 may extend in a plane perpendicular to the axial direction A.

[0037] The inverter cover member 203 is provided to cover the opening of the inverter housing chamber S4 in the case member 200. The inverter cover member 203 may be formed as a single piece.

[0038] The inverter device 90 may be in the form of a module and may be fixed to the wall portion forming the inverter case portion 24 by bolts or the like. The inverter device 90 comprises a power module PM (described later) including a plurality of switching elements that constitute the inverter circuit, a control board SB (described later) on which a control device for controlling the inverter circuit is mounted, and a smoothing capacitor CM (described later) for smoothing the voltage between the positive and negative poles on the DC side of the inverter circuit. The inverter device 90 may also further include various sensors such as current sensors, filters such as Y capacitors (not shown), various wiring (including connectors and busbars), etc. The inverter device 90 may also include a cooling water channel (described later) for cooling the power module PM. The smoothing capacitor CM may be in the form of a module formed by molding a plurality of capacitor elements and terminals with resin.

[0039] Here, as shown in Figure 3, the direction in which the rotating electric machine 1 and the inverter device 90 are aligned in an axial view along the axial direction A is defined as the first direction X, and the direction perpendicular to both the axial direction A and the first direction X is defined as the second direction Y. Furthermore, one side of the first direction X is defined as the first side X1 of the first direction, the other side of the first direction X (opposite to the first side X1 of the first direction X) is defined as the second side X2 of the first direction, one side of the second direction Y is defined as the first side Y1 of the second direction, and the other side of the second direction Y (opposite to the first side Y1 of the second direction Y) is defined as the second side Y2 of the second direction. The first side X1 of the first direction is the side in the first direction X where the rotating electric machine 1 is positioned relative to the inverter device 90.

[0040] In the following description, the second direction is assumed to have a vertical component. In this case, the second direction may be parallel to the direction of gravity (vertical direction) or inclined when the vehicle drive unit 100 is mounted on the vehicle VC. For example, the vehicle drive unit 100 may be mounted on the vehicle VC in a orientation where the first side Y1 of the second direction is the upper side V1 and the second side Y2 of the second direction is the lower side V2. Alternatively, the vehicle drive unit 100 may be mounted on the vehicle VC in a orientation where the first side X1 of the first direction is the front side L1 (front side of the vehicle longitudinal direction L) and the second side X2 of the first direction is the rear side L2 (rear side of the vehicle longitudinal direction L). As shown in Figure 1, the vehicle drive unit 100 may be mounted in the vehicle VC at a position L1 forward of the center of the vehicle longitudinal direction L. Furthermore, if the vehicle drive unit 100 is mounted on the vehicle VC at a rearward L2 from the center of the vehicle's longitudinal direction L, the vehicle drive unit 100 can be mounted on the vehicle VC in a orientation where the first side X1 in the first direction is at the rear L2 and the second side X2 in the first direction is at the front L1, thereby enabling the inverter device 90 to be positioned closer to the center of the vehicle's longitudinal direction L than the rotating electric machine 1. In this case, when the vehicle drive unit 100 is mounted at a rearward L2 from the center of the vehicle's longitudinal direction L in the vehicle VC, the pair of wheels W driven by the vehicle drive unit 100 may be, for example, a pair of left and right rear wheels.

[0041] When the vehicle VC is equipped with a pair of left and right front wheels and a pair of left and right rear wheels, the wheel that is not driven by the vehicle drive unit 100 (in the example shown in Figure 1, the pair of left and right rear wheels) can be driven by a drive unit other than the vehicle drive unit 100. The drive unit other than the vehicle drive unit 100 may be, for example, a drive unit configured to transmit the output torque of an internal combustion engine (an example of a driving force source other than a rotating electric machine) to the pair of wheels to be driven, a drive unit configured to transmit the output torque of a rotating electric machine (a rotating electric machine other than the rotating electric machine 1 provided in the vehicle drive unit 100) to the pair of wheels to be driven, or a drive unit configured to transmit the output torque of both an internal combustion engine and a rotating electric machine (a rotating electric machine other than the rotating electric machine 1 provided in the vehicle drive unit 100) to the pair of wheels to be driven. The drive unit other than the vehicle drive unit 100 may also be a drive unit with the same configuration as the vehicle drive unit 100.

[0042] Incidentally, the rotating electric machine 1 of the vehicle drive unit 100 may have the largest size in the second direction when viewed axially. The size of the rotating electric machine 1 is determined according to the required output, etc. Therefore, in order to reduce the overall size of the vehicle drive unit 100 in the second direction, it is useful to arrange the main components of the vehicle drive unit 100 (main components other than the rotating electric machine 1) so that they overlap with the rotating electric machine 1 when viewed in the first direction X. In particular, if the vehicle drive unit 100 includes an output gear 30 with a relatively large outer diameter, the positional relationship between the output gear 30 and the rotating electric machine 1 can significantly affect the overall size of the vehicle drive unit 100 in the second direction.

[0043] Taking this into consideration, in this embodiment, the output gear 30 is preferably positioned relative to the rotating electric machine 1 such that it does not significantly affect the overall size of the vehicle drive unit 100 in the second direction. That is, the offset amount in the second direction Y between the central axis of the output gear 30 (i.e., the second axis C2) and the central axis of the rotating electric machine 1 (i.e., the first axis C1) is set to be relatively small. Specifically, a pair of output members 6 concentric with the central axis of the output gear 30 are positioned so as to overlap with the rotor shaft 15 of the vehicle drive unit 100 in a first-direction view. In this case, the relative positions of the output gear 30 and the rotating electric machine 1 may be set such that the outer shape of the output member 6 (e.g., the circular outer shape portion) overlaps with the outer shape of the rotor shaft 15 (e.g., the circular outer shape portion) in a first-direction view. Alternatively, the relative positions of the output members 6 may be set such that the central axis of the output member 6 (i.e., the second axis C2) overlaps with the rotor axis 15 in a first-direction view, or the relative positions of the output members 6 may be set such that the central axis of the rotor axis 15 (i.e., the first axis C1, which is the axis of the rotor axis 15) overlaps with the pair of output members 6 in a first-direction view. By arranging the output gear 30 and the rotating electric machine 1 in such a relative position, the influence of the output gear 30 on the overall size of the vehicle drive system 100 in the second direction can be reduced or eliminated. In other words, the overall size of the vehicle drive system 100 in the second direction is substantially determined by the size of the rotating electric machine 1 (and consequently the size of the motor case 21), so under the same size conditions of the rotating electric machine 1, the overall size of the vehicle drive system 100 in the second direction can be minimized.

[0044] Next, with further reference to Figure 4 and subsequent figures, a characteristic configuration of the arrangement of the inverter device 90 according to this embodiment will be described.

[0045] Figure 4 is a schematic diagram of the vehicle drive unit 100 in an axial view, showing different parts offset in the axial direction A with line 400 as the boundary. Figure 5 is a schematic diagram of the vehicle drive unit 100 in an axial view as seen from the axial first side A1, with a portion shown in perspective so that the interior is visible. Figure 6 is an explanatory diagram of a modified example of Figure 5.

[0046] In this embodiment, the inverter case portion 24 has an L-shape when viewed in the axial direction and includes an upper case portion 241 and a lateral case portion 242. The upper case portion 241 and the lateral case portion 242 form a housing space that communicates with each other.

[0047] Specifically, the upper case portion 241 extends in the first direction X and axial direction A, forming a first inverter housing chamber S41 inside. The lateral case portion 242 extends in the second direction Y and axial direction A, forming a second inverter housing chamber S42 inside. In this case, the inverter case portion 24 extends axially A around the differential case portion 50 and the first output member 61 (in a manner opposite to the differential case portion 50 and the first output member 61 in the first direction X and the second direction Y). That is, the inverter case portion 24 forms a peripheral wall portion 250 (a peripheral wall portion relating to a part of the entire circumference around the second shaft C2) that extends so as to surround the differential case portion 50 and the first output member 61 in the output shaft case portion 23. The peripheral wall portion 250 extends in a manner that partitions the inverter housing chamber S4 from the output shaft housing chamber S3. In this case, the peripheral wall portion 250 includes a first wall portion 251 extending in the first direction X and axial direction A, and a second wall portion 252 extending in the second direction Y and axial direction A, and the first wall portion 251 and the second wall portion 252 overlap the output gear 30 in an axial view. As a result, the inverter housing chamber S4 can be partitioned from the output shaft housing chamber S3 without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the peripheral wall portion 250.

[0048] The first inverter housing chamber S41 and the second inverter housing chamber S42 may be in communication with each other and may be perpendicular to each other at the corners of the second side X2 in the first direction and the first side Y1 in the second direction. In this case, the inverter case portion 24 has a corner 249 (see Figure 4) of the second side X2 in the first direction and the first side Y1 in the second direction.

[0049] The extension ranges of the first inverter housing S41 and the second inverter housing S42 overlap in the axial direction A. For example, the extension ranges of the first inverter housing S41 and the second inverter housing S42 in the axial direction A may be approximately the same. Alternatively, one of the first inverter housing S41 and the second inverter housing S42 may be set to have a shorter axial extension range than the other.

[0050] Preferably, the inverter case section 24 is formed so as not to affect the overall size of the case 2 in the second direction Y, in order to prevent an increase in the overall size of the case 2. In this embodiment, the overall size of the case 2 in the second direction Y is determined by the overall size of the rotating electric machine 1 in the second direction Y (see lines P0 and P2 in Figures 3 and 4), specifically, by the overall size of the motor case section 21 in the second direction Y. Therefore, the inverter case section 24 is positioned at the second-to-second-side Y2 position of the motor case section 21, rather than at the position furthest to the first-to-second-side Y1 position in the second direction (see line P2 in Figures 3 and 4). In this case, the overall size of the case 2 in the second direction Y can be reduced.

[0051] Furthermore, the upper case portion 241 of the inverter case portion 24 is preferably positioned between both end faces of the case member 200 in the axial direction A. That is, the inverter case portion 24 is preferably positioned between the axial direction A of the joint surface (matting surface) 221 between the motor cover member 201 and the case member 200 and the joint surface (matting surface) 222 between the differential cover member 202 and the case member 200. In this case, compared to the case in which the inverter case portion 24 is formed protruding from both end faces of the case member 200 in the axial direction A, it is easier to position the inverter case portion 24 in the second direction, second side Y2, rather than in the position furthest to the first side Y1 in the second direction on the differential cover member 202. That is, the second side Y2 of the second direction of the inverter case portion 24 can be positioned in the second direction, second side Y2, rather than in the flanges related to the mating surfaces 221 and 222, making it easier to position the inverter case portion 24 in the second direction, second side Y2, rather than in the position furthest to the first side Y1 in the second direction on the differential cover member 202.

[0052] Furthermore, the inverter case section 24 is preferably formed so as not to affect the overall dimensions of the case 2 in the first direction X, in order to prevent an increase in the overall dimensions of the case 2. In this embodiment, the boundary (outer shape) of the second side X2 in the first direction of the overall dimensions of the case 2 in the first direction X is determined by the dimensions of the differential gear mechanism 5, and specifically by the dimensions of the transmission mechanism case section 22 in the first direction X. Therefore, the inverter case section 24 is positioned closer to the first side X1 in the first direction (the side closer to the rotating electric machine 1) than the position of the second side X2 in the first direction of the transmission mechanism case section 22 (the end position of the second side X2 in the first direction, see line P1 in Figures 3 and 4). In this case, the overall dimensions of the case 2 in the first direction X can be reduced.

[0053] In this embodiment, the inverter housing chamber S4 may have an opening in the first direction X on the second side X2 in the first direction, and in this case, the inverter cover member 203 may extend in the axial direction A and the second direction Y. In this case, the inverter cover member 203 may extend towards the first side X1 in the first direction (the side closer to the rotating electric machine 1) rather than the position of the second side X2 in the first direction of the transmission mechanism case portion 22.

[0054] The capacities of the first inverter housing chamber S41 and the second inverter housing chamber S42 are arbitrary, but may be determined according to the components of the inverter device 90 to be housed. In this embodiment, as an example, the size of the rotating electric machine 1 in an axial view is larger than the size of the output gear 30, so around the second axis C2, dead space (space between the first side X1 in the first direction and between the position of the first side X1 in the first direction and between the position of the first side Y1 in the second direction of the motor case 21 is more likely to be formed on the first side Y1 in the second direction than on the second side X2 in the first direction) is formed. Therefore, the dimension of the first inverter housing chamber S41 in the second direction Y (for example, the maximum dimension or the average dimension) may preferably be set to be larger than the same dimension of the second inverter housing chamber S42 in the first direction X. In this case, it becomes easy to position the inverter case 24 at a position Y2 in the second direction that is further to the second side in the second direction than the position Y1 in the motor case 21, and at a position X1 in the first direction (closer to the rotating electric machine 1) that is further to the first side in the first direction than the position X2 in the first direction of the transmission mechanism case 22.

[0055] Hereinafter, the components of the inverter device 90 that are located within the upper case portion 241 will be referred to as the first inverter portion 91, and the components that are located within the side case portion 242 will be referred to as the second inverter portion 92. The first inverter portion 91 may preferably include a smoothing capacitor CM, and the second inverter portion 92 may preferably include a power module PM. This arrangement is suitable when the required mounting space thickness (height) of the smoothing capacitor CM is greater than that of the power module PM.

[0056] As shown in Figure 4, in this embodiment, the rotating electric machine 1 and the first inverter section 91 or upper case section 241 of the inverter device 90 are arranged such that their respective vertical direction V arrangement areas overlap. Therefore, as an example, the horizontal direction H perpendicular to the axial direction A (in other words, the direction perpendicular to both the axial direction A and the vertical direction V) can be defined as the first direction X. In this case, as shown in Figure 4, the second direction Y is parallel to the vertical direction V. Alternatively, as another example, the direction along a virtual straight line passing through the first axis C1 and the center of the first inverter section 91 or upper case section 241 in an axial view can also be defined as the first direction X. Here, the center of the first inverter section 91 or upper case section 241 in an axial view can be the centroid of the figure forming the outer shape (outer edge) of the first inverter section 91 or upper case section 241 in an axial view. In the example shown in Figure 4, the horizontal direction H perpendicular to the axial direction A and the direction along the virtual straight line in an axial view are parallel to each other. In other words, in the example shown in Figure 4, the first direction X is defined in the same direction regardless of which of the two definitions above is used.

[0057] Furthermore, as shown in Figure 4, the first output member 61 is positioned between the rotating electric machine 1 and the inverter device 90 in the first direction X at a position in the second direction Y where both the rotating electric machine 1 and the inverter device 90 (or the second inverter section 92 or the side case section 242 of the inverter device 90) are located. The portion of the first output member 61 that is positioned between the rotating electric machine 1 and the inverter device 90 in the first direction X overlaps with the axial A positioning area of ​​the rotating electric machine 1 and the axial A positioning area of ​​the inverter device 90 (see Figure 3). Then, as shown in Figure 4, the output gear 30 may be positioned so as to overlap with the rotating electric machine 1 and the inverter device 90 in an axial view. Specifically, the output gear 30 may be positioned such that the portion of the output gear 30 on the first side X1 in the first direction overlaps with the rotating electric machine 1 in an axial view, and the portion of the output gear 30 on the second side X2 in the first direction overlaps with the inverter device 90 in an axial view. As shown in Figure 3, the output gear 30 is positioned on one side of the axial direction A (specifically, the second axial side A2) relative to the rotating electric machine 1 and the inverter device 90.

[0058] In this embodiment, the rotating electric machine 1 and the inverter device 90 may be arranged in such a manner that their respective axial direction A arrangement areas do not overlap. That is, the inverter device 90 or the inverter case 24 may be positioned on the second side X2 in the first direction relative to the rotating electric machine 1. However, the axial direction A arrangement area of ​​the inverter device 90 or the inverter case 24 may overlap with that of the axial direction A1 of the first side A1 of the rotating electric machine 1. The same applies to the first direction X. Specifically, the inverter device 90 or the inverter case 24 may be positioned on the second side X2 in the first direction relative to the rotating electric machine 1. That is, the inverter device 90 or the inverter case 24 may be positioned in an area that overlaps with the portion of the transmission mechanism 3 around the second axis C2 (the portion of the transmission mechanism 3 excluding the reduction mechanism 34) in the second direction. However, the inverter device 90 or the inverter case portion 24 may have an overlap in its arrangement area in the first direction X with a portion of the first side X1 in the first direction of the rotating electric machine 1 or the second side X2 in the first direction of the reduction mechanism 34.

[0059] In this embodiment, when mounted on a vehicle, at least a portion (only a portion in the example shown in Figure 4) of the lateral case portion 242 of the inverter device 90 is positioned below the second axis C2 V2. However, when mounted on a vehicle, as long as the position of the lateral case portion 242 of the inverter device 90 in the second direction Y overlaps with the position of the first output member 61 in the second direction Y, the entire lateral case portion 242 of the inverter device 90 can also be positioned above the second axis C2 V1, in an axial view.

[0060] In this embodiment, the first output member 61 is positioned between the first direction X of the rotating electric machine 1 and the inverter device 90 at the second direction Y where both the rotating electric machine 1 and the inverter device 90 are located. Therefore, the arrangement areas in the second direction Y of the rotating electric machine 1, the inverter device 90, and the output gear 30, which is arranged coaxially with the first output member 61, overlap, making it possible to reduce the overall size of the vehicle drive unit 100 in the second direction Y. In this embodiment, the output gear 30 is positioned so as to overlap with the rotating electric machine 1 and the inverter device 90 in an axial view. Therefore, while the first output member 61 is positioned between the first direction X of the rotating electric machine 1 and the inverter device 90 as described above, by effectively utilizing the space that overlaps with the output gear 30 in an axial view, the rotating electric machine 1 and the inverter device 90 can be positioned closer to the first direction X. This also makes it possible to reduce the overall size of the vehicle drive unit 100 in the first direction X.

[0061] In this way, according to this embodiment, the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y can be reduced, that is, the dimensions of the vehicle drive unit 100 in the axial view can be reduced. This improves the mountability of the vehicle drive unit 100 on the vehicle VC.

[0062] In this embodiment, the rotating electric machine 1 and the second inverter section 92 or side case section 242 of the inverter device 90 are arranged separately on both sides in the first direction with respect to the first output member 61, which is arranged coaxially with the output gear 30. As a result, it is easier to increase both the proportion of the rotating electric machine 1 overlapping with the output gear 30 in an axial view and the proportion of the second inverter section 92 or side case section 242 of the inverter device 90 overlapping with the output gear 30 in an axial view, thereby making it easier to reduce the axial dimensions of the vehicle drive unit 100.

[0063] Furthermore, according to this embodiment, the inverter case section 24 that houses the inverter device 90 includes an upper case section 241 and a lateral case section 242. Compared to the case where the inverter case section 24 consists of only the upper case section 241 or only the lateral case section 242, the overall capacity (volume of the inverter housing chamber S4) can be efficiently increased. This makes it possible to achieve an efficient arrangement (layout) of the inverter device 90 without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the inverter device 90.

[0064] In particular, according to this embodiment, the first inverter section 91 or the upper case section 241 of the inverter device 90 extends over a relatively wide range in the first direction X, overlapping with the second axis C2 of the first output member 61 in a second-direction view. In the illustrated example, the first inverter section 91 or the upper case section 241 of the inverter device 90 extends from the second axis C2 to the first side X1 in the first direction in an axial view. This makes it possible to arrange the first inverter section 91, which has a relatively large size in the first direction X, in the first inverter section 91 or the upper case section 241. In this embodiment, the first inverter section 91 is a smoothing capacitor CM, but it may also be a power module PM, or it may include both the first inverter section 91 and the smoothing capacitor CM.

[0065] Furthermore, according to this embodiment, it is also possible to consolidate various wiring related to the inverter device 90 (for example, busbar B1 as shown in Figure 4) by utilizing the area (corner region) that overlaps with the corner 249 of the inverter case 24 in an axial view. Since this area that overlaps with the corner 249 of the inverter case 24 in an axial view includes the area that overlaps with the output gear 30 in an axial view, various wiring can be consolidated without increasing the axial dimensions of the vehicle drive unit 100. Therefore, connectors and the like can be placed in the area that overlaps with the corner 249 of the inverter case 24 in an axial view. The various wiring to be consolidated is arbitrary, but may include, for example, high-voltage wiring (power supply wiring) for receiving power from a high-voltage battery BA (see Figure 1) and low-voltage wiring for the control system. In addition, some or all of the various wiring placed in the area that overlaps with the corner 249 of the inverter case 24 in an axial view may be placed outside the case 2 (inverter case 24). For example, in the example shown in Figure 3, connectors CN10 and CN11 are arranged in an area that overlaps with the corner 249 of the inverter case 24 in an axial view. In this case, connector CN10 is located on the second axial side A2, and connector CN11 is located on the first axial side A1. The male or female side of connectors CN10 and CN11 may be fixed to the inverter case 24. Connectors CN10 and CN11 may form a wiring section for electrically connecting a wiring cable (not shown) located outside the case 2 to the inverter device 90. One of connectors CN10 and CN11 may be for high-voltage wiring to receive power from a high-voltage battery BA (see Figure 1), and the other may be for low-voltage wiring of the control system. In this case, an appropriate insulation distance can be easily secured between connectors CN10 and CN11. In the modified example, one of connectors CN10 or CN11 may be omitted.

[0066] Furthermore, in this embodiment, the high-voltage connector CN1 (see Figure 4) for receiving power from the battery BA may be located on the second direction first side Y1 of the reduction mechanism 34. In this case, the connector CN1 can be located using the dead space that is easily formed on the second direction first side Y1 of the reduction mechanism 34 (dead space that does not affect the size of the vehicle drive unit 100 in the second direction Y). In this case, the high-voltage connector CN1 (see Figure 4) may be located in place of the connector CN10, CN11 shown in Figure 3, which is for the high-voltage system.

[0067] Incidentally, in the differential gear mechanism 5, the output gear 30 tends to be the largest component of the differential gear mechanism 5 in terms of its size around the second shaft C2. Therefore, when the output gear 30 of the differential gear mechanism 5 is positioned closer to the second axial side A2, the space around the second shaft C2 that is on the first axial side A1 side of the space around the output gear 30 can be secured in a manner that is relatively wide in the radial direction and continuous with the axial direction A, allowing other components (such as the water channels described later) to be arranged efficiently.

[0068] More specifically, in this embodiment, around the second shaft C2, the output gear 30, the differential case 50, and the first output member 61 are mainly provided in order from the second axial side A2 toward the first axial side A1. In this case, the mounting space around the second shaft C2 (mounting space for other members) gradually increases from the second axial side A2 toward the first axial side A1. That is, the mounting space around the second shaft C2 (mounting space for other members) gradually increases from the second axial side A2 toward the first axial side A1. Therefore, in this embodiment, the vehicle drive unit 100 may have a mounting portion MT (mounting portion) for the vehicle body of the vehicle VC at the axial position A of the differential case 50 around the second shaft C2. In this case, as shown in Figure 4, the mounting portion MT may be arranged in an area that overlaps with the output gear 30 and the inverter device 90 (or inverter case 24) in an axial view. This makes it possible to efficiently establish the mounting portion MT by utilizing the space around the second shaft C2 that tends to be dead space. The mounting section MT may be located outside of case 2.

[0069] Furthermore, in this embodiment, as described above, the mounting space around the second axis C2 (mounting space for other components) gradually increases from the axial second side A2 to the axial first side A1. Therefore, the dimension of the upper case portion 241 of the inverter device 90 in the second direction Y (the dimension of the second inverter housing chamber S42 in the second direction Y) can also be gradually increased from the axial second side A2 to the axial first side A1 without changing the position of the upper case portion 241 at the furthest point on the second direction first side Y1. In this case, the various components of the inverter device 90 may be arranged in the upper case portion 241 in such a manner that the dimension of the component located on the axial first side A1 is smaller than that of the component located on the axial second side A2.

[0070] In this embodiment, the control board of the inverter device 90 may be positioned on the second direction first side Y1 of the output gear 30. In this case, the control board may be positioned in a direction where the second direction Y is the normal direction. In this case, since the dimension of the control board in the second direction Y is relatively small, it may still be possible to position the inverter case 24 on the second direction second side Y2 rather than the position on the differential cover member 202 that is closest to the first direction first side Y1.

[0071] Next, with reference to Figures 6 and 7, the oil lubrication structure and cooling structure of the vehicle drive unit 100 in this embodiment will be outlined.

[0072] Figure 6 is a schematic diagram of the vehicle drive unit 100 in an axial view as seen from the first axial side A1, with a portion shown in perspective to allow the interior to be seen. Figure 6 corresponds to a modified example of a water-cooled structure compared to the oil-cooled structure shown in Figure 5. Figure 7 is a schematic diagram of the interior of the vehicle drive unit 100 (the interior in a cross-sectional view along line QQ in Figure 3) in an axial view as seen from the first axial side A1, showing a different part offset in the axial direction A with line 700 as the boundary. The water pump W / P is also schematically shown in Figure 7. In addition, the outer circumference of the output gear 30 is shown by a dashed line in Figure 7 for the purpose of explaining the positional relationship.

[0073] In this embodiment, the rotating electric machine 1 may be oil-cooled, water-cooled, or a combination thereof. In the case of oil cooling, the inverter housing chamber S4 may be sealed in such a manner that it does not fluidly communicate with the motor housing chamber S1, the transmission mechanism housing chamber S2, and the output shaft housing chamber S3. In this case, as shown in Figure 5, a partition wall may not be formed between the motor housing chamber S1 and the output shaft housing chamber S3, and they may communicate with each other. In this case, the wiring connection portion 600 between the rotating electric machine 1 and the inverter device 90 may be provided in such a manner that it penetrates the axial partition wall portion 29 that separates the motor housing chamber S1 or the output shaft housing chamber S3 from the inverter housing chamber S4. The wiring connection portion 600 may be in the form of a high-voltage connector or terminal block for connecting the rotating electric machine 1 and the power module PM of the inverter device 90. The wiring connection portion 600 may be located in an area that overlaps with the output gear 30 in an axial view.

[0074] On the other hand, in the case of a water-cooled system, the inverter housing chamber S4 may be fluidly connected to the motor housing chamber S1, etc. In this case, for example, as shown in Figure 6, part or all of the wall separating the inverter housing chamber S4 and the motor housing chamber S1 (a wall like the partition wall 29 in Figure 5) may be eliminated, making it easier to route the wiring between the rotating electric machine 1 and the inverter device 90. For example, in the example shown in Figure 6, the wiring connection part 600 between the rotating electric machine 1 and the inverter device 90 is provided in a manner that communicates with both the inverter housing chamber S4 and the motor housing chamber S1. In this case, as shown in Figure 6, a partition wall 28 may be formed between the motor housing chamber S1 and the output shaft housing chamber S3.

[0075] If the rotating electric machine 1 is water-cooled, a cooling water channel (hereinafter referred to as "motor cooling water channel 129" for distinction) may be formed around the outer circumference of the stator core 12. In this case, the motor cooling water channel 129 may be formed in the case member 200, or in another support member 204 (a component of the motor case portion 21 of the case 2) that is coupled to the case member 200. In this case, the other support member 204 may be cylindrical in shape and may be made of a material with high thermal conductivity, such as aluminum, and may be integrated with the radially outer side of the stator core 12 by shrink-fitting, casting, etc. This reduces the thermal resistance between the support member 204 and the stator core 12, and allows for efficient cooling of coils, etc., through the stator core 12. In this case, the other support member 204 may also be integrated with the case member 200 by fastening, etc. Furthermore, if the rotor shaft 15 is hollow with an axial hole, the motor cooling water channel 129 may communicate with the axial hole of the rotor shaft 15.

[0076] In this embodiment, the inverter case portion 24 of case 2 has a cooling water passage (hereinafter referred to as the "inverter cooling water passage 99" for distinguishing it) through which cooling water (for example, cooling water containing long-life coolant) that cools the inverter device 90 passes.

[0077] The inverter cooling water passage 99 may be positioned in an area that overlaps with the output gear 30 in an axial view. In this case, an efficient arrangement (layout) of the inverter cooling water passage 99 can be achieved without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the inverter cooling water passage 99.

[0078] When the smoothing capacitor CM of the inverter device 90 is located in the upper case portion 241, the inverter cooling water passage 99 may have a water passage portion (hereinafter also referred to as the "upper water passage portion") (not shown) that extends over an area overlapping with the entire or a part of the smoothing capacitor CM in a second view. In this case, the upper water passage portion may be located in the second Y2 in the second direction from the smoothing capacitor CM. In this case, the upper water passage portion may be formed in the first wall portion 251 of the peripheral wall portion 250 described above.

[0079] When the power module PM of the inverter device 90 is arranged in the lateral case portion 242, the inverter cooling water channel 99 may have a water channel portion (hereinafter also referred to as the "lateral water channel portion 9902") that extends to an area overlapping with the entire power module PM or a part of it in a first view. In this case, the lateral water channel portion 9902 may be located on the first side X1 in the first direction from the power module PM. In this case, the lateral water channel portion 9902 may be formed on the second wall portion 252 of the peripheral wall portion 250 described above. The power module PM may have a plurality of fins F formed on the surface of the housing on the first side X1 in the first direction (the surface that comes into contact with the cooling water in the inverter cooling water channel 99).

[0080] Furthermore, when the power module PM of the inverter device 90 is arranged in the lateral case portion 242, the lateral waterway portion 9902 may extend in the second direction Y, together with the power module PM, from the second side Y2 of the second direction relative to the central axis (i.e., the second axis C2) of the first output member 61 to the first side Y1 of the second direction relative to the same central axis (i.e., the second axis C2). Here, the separation distance in the first direction X between the lateral case portion 242 and the differential case portion 50, which extend in the axial direction A and the second direction Y, is minimized at each position along the second direction Y where it overlaps with the central axis (i.e., the second axis C2) of the differential case portion 50 in the first direction view, and increases as it moves away from that overlapping position towards the first side Y1 or the second side Y2 of the second direction. Taking advantage of this point, the lateral water channel portion 9902 of the inverter cooling water channel 99 may have an inlet portion 991 and a chamber portion 992 in a region where the distance from the differential case portion 50 in the first direction X is relatively large (for example, in an axial view, the region Y2 on the second side of the second direction from the first output member 61). The inlet portion 991 is the part into which the cooling water discharged from the water pump W / P (see Figure 7) is introduced. In the following, the terms "upstream side" and "downstream side" are used in reference to the flow of the cooling water.

[0081] The chamber portion 992 may extend axially along the entire axial length A of the lateral channel portion 9902 of the inverter cooling water channel 99. The chamber portion 992 has a significantly larger cross-sectional area than the inlet portion 991 and significantly less resistance than the flow path portion in contact with the power module PM (for example, the flow path around the fin F). The cross-sectional area of ​​each position along the second direction of the inverter cooling water channel 99 is the cross-sectional area when cut by a plane perpendicular to the flow direction, and in this case, it corresponds to the cross-sectional area when cut by a plane perpendicular to the second direction.

[0082] Therefore, by providing the chamber section 992 adjacent to the inlet section 991 from the downstream side, the required flow rate of cooling water introduced into the inverter cooling water channel 99 can be effectively secured. A chamber chamber 993 similar to the chamber section 992 may also be provided downstream of the flow path portion in contact with the power module PM in the lateral water channel portion 9902 of the inverter cooling water channel 99.

[0083] Furthermore, if the motor cooling water passage 129 described above is provided, the inverter cooling water passage 99 may communicate with the motor cooling water passage 129. In this case, the inverter cooling water passage 99 may be located upstream of the motor cooling water passage 129, and in this case, the motor cooling water passage 129 may have an outlet (not shown) for returning the cooling water to the water pump W / P. The outlet (not shown), together with the inlet 991 described above, may be located in a region that overlaps with the output gear 30 in an axial view. In this case, an efficient arrangement of the inverter cooling water passage 99 can be achieved without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the inverter cooling water passage 99.

[0084] Furthermore, if the motor cooling water passage 129 described above is provided, a water passage for connecting the inverter cooling water passage 99 and the motor cooling water passage 129 (hereinafter also referred to as the "connecting water passage 1290") may be formed in the case 2. That is, the connecting water passage 1290 may be realized as a water passage inside the case, similar to the motor cooling water passage 129 and the inverter cooling water passage 99. The connecting water passage 1290 may extend in the axial direction A and the first direction X. Alternatively, the connecting water passage 1290 may extend in the axial direction A, the first direction X and the second direction Y. In this case, the connecting water passage 1290 may be formed in the part of the case 2 that forms the motor case portion 21 and the transmission mechanism case portion 22 or the output shaft case portion 23. Also, the connecting water passage 1290 may be located above the first output member 61 in an axial view and in a region that overlaps with the output gear 30 in an axial view.

[0085] Next, with reference to Figure 8 and subsequent figures, the vehicle drive unit 100A according to Embodiment 2 will be described. In the following description of Embodiment 2 and the related figures, components that may be substantially the same as those in Embodiment 1 described above may be given the same reference numerals and their descriptions may be omitted.

[0086] Figure 8 is a schematic two-view drawing of the vehicle drive unit 100A according to this embodiment, Figure 9 is a schematic drawing of the vehicle drive unit 100A in a direction perpendicular to the two directions of the two-view drawing of Figure 8 (i.e., a first-direction view), and Figure 10 is an explanatory diagram of a modified example of Figure 9. Figures 9 and 10 show different portions offset in the first direction X with line 802 as the boundary.

[0087] The vehicle drive unit 100A according to Example 2 differs from the vehicle drive unit 100 according to Example 1 described above mainly in the arrangement of the inverter device and inverter case. Specifically, the vehicle drive unit 100A according to Example 2 differs from the vehicle drive unit 100 according to Example 1 described above in that case 2 and inverter device 90 are replaced by case 2A and inverter device 90A, respectively.

[0088] Case 2A differs from Case 2 in the above-described embodiment 1 in that the inverter case section 24 is replaced with the inverter case section 24A.

[0089] In this embodiment, the inverter case portion 24A differs from the inverter case portion 24 of Embodiment 1 described above (an L-shaped form in an axial view) in that, in an axial view, it extends only in the second direction first side Y1 from the first output member 61.

[0090] Specifically, the inverter case portion 24A extends in the first direction X and axial direction A, forming an inverter housing chamber S4 inside. In this case, as shown in Figures 8 and 9, the inverter case portion 24A extends in the axial direction A in a manner that is opposite to the differential case portion 50 and the first output member 61 in the second direction Y. That is, the inverter case portion 24A extends so as to cover the first side Y1 in the second direction of the differential case portion 50 in the transmission mechanism case portion 22 and the first side Y1 in the second direction of the first output member 61 in the output shaft case portion 23. In this way, the inverter case portion 24A extends in the first direction X and axial direction A, and overlaps with the output gear 30 in an axial view.

[0091] Preferably, the inverter case section 24A is formed so as not to affect the overall size of the case 2A in the second direction Y, in order to prevent an increase in the overall size of the case 2A. In this embodiment, the overall size of the case 2A in the second direction Y is determined by the overall size of the rotating electric machine 1 in the second direction Y, and specifically by the overall size of the motor case section 21 in the second direction Y. Therefore, the inverter case section 24A is positioned at the second-to-second-side Y2 position of the motor case section 21, rather than at the position furthest to the first-to-second-side Y1 position in the second direction (see line P2 in Figure 8). In this case, the overall size of the case 2A in the second direction Y can be reduced.

[0092] Furthermore, the inverter case portion 24A is preferably positioned between both end faces of the case member 200 in the axial direction A. That is, the inverter case portion 24A is preferably positioned between the axial direction A of the joint surface (matting surface) 221 between the motor cover member 201 and the case member 200 and the joint surface (matting surface) 222 between the differential cover member 202 and the case member 200. In this case, compared to the case where the inverter case portion is formed protruding from both end faces of the case member 200 in the axial direction A, it is easier to position the inverter case portion 24A on the differential cover member 202 at the second side Y2 rather than at the position on the first side Y1 in the second direction. That is, since the inverter case portion 24A can be extended below the flanges related to the mating surfaces 221 and 222, it becomes easier to position the inverter case portion 24A on the differential cover member 202 at the second side Y2 rather than at the position on the first side Y1 in the second direction.

[0093] Furthermore, the inverter case section 24A is preferably formed so as not to affect the overall dimensions of the case 2A in the first direction X, in order to prevent an increase in the overall dimensions of the case 2A. In this embodiment, the boundary (outer shape) of the second side X2 in the first direction of the overall dimensions of the case 2A in the first direction X is determined by the dimensions of the differential gear mechanism 5, and specifically by the dimensions of the transmission mechanism case section 22 in the first direction X. Therefore, the inverter case section 24A or the inverter device 90A is positioned closer to the first side X1 in the first direction (closer to the rotating electric machine 1) than the position of the second side X2 in the first direction of the transmission mechanism case section 22 (the end position of the second side X2 in the first direction, see line P1 in Figure 8). In this case, the overall dimensions of the case 2A in the first direction X can be reduced.

[0094] In the modified version, a portion of the inverter case 24A or a portion of the inverter device 90A may protrude beyond the position of the second side X2 in the first direction of the transmission mechanism case 22 (the end position of the second side X2 in the first direction). However, in this case, the increase in size caused by the protruding portion can be minimized by positioning the relatively large power module PM and smoothing capacitor CM, among the various components of the inverter device 90A, on the first side X1 in the first direction (closer to the rotating electric machine 1) rather than the position of the second side X2 in the first direction of the transmission mechanism case 22 (the end position of the second side X2 in the first direction).

[0095] As shown in Figure 8, in this embodiment as well, the rotating electric machine 1 and the inverter device 90A or inverter case section 24A are arranged such that their respective vertical direction V arrangement areas overlap. Therefore, as an example, the horizontal direction H perpendicular to the axial direction A (in other words, the direction perpendicular to both the axial direction A and the vertical direction V) can be defined as the first direction X. In this case, as shown in Figure 8, the second direction Y is parallel to the vertical direction V. Alternatively, as another example, the direction along a virtual straight line passing through the first axis C1 and the center of the first inverter section 91 or inverter case section 24A in an axial view can also be defined as the first direction X. Here, the center of the first inverter section 91 or inverter case section 24A in an axial view can be the centroid of the figure forming the outer shape (outer edge) of the first inverter section 91 or inverter case section 24A in an axial view. In the example shown in Figure 8, the horizontal direction H perpendicular to the axial direction A and the direction along the virtual straight line in an axial view are parallel to each other. In other words, in the example shown in Figure 8, the first direction X is defined in the same direction regardless of which of the two definitions above is used.

[0096] Furthermore, as shown in Figure 8, the output gear 30 is positioned so as to overlap with the rotating electric machine 1 and the inverter device 90A in an axial view. Specifically, the output gear 30 is positioned such that the portion of the output gear 30 on the first side X1 in the first direction overlaps with the rotating electric machine 1 in an axial view, and the portion of the output gear 30 on the first side Y1 in the second direction overlaps with the inverter device 90A in an axial view. As shown in Figure 8, the output gear 30 is positioned on one side of the axial direction A (specifically, the second axial side A2) relative to the rotating electric machine 1 and the inverter device 90A. The rotating electric machine 1 and the inverter device 90A may be positioned so that their respective axial direction A configurations overlap.

[0097] In this embodiment, the inverter device 90A or the inverter case 24A may be positioned on the second side X2 in the first direction relative to the rotating electric machine 1. That is, the inverter device 90A or the inverter case 24A may be positioned in a region that overlaps with the portion of the transmission mechanism 3 around the second axis C2 (the portion of the transmission mechanism 3 excluding the reduction mechanism 34) in a second-direction view. However, the inverter device 90A or the inverter case 24A may have a portion of the first side X1 in the first direction that overlaps with a portion of the second side X2 in the first direction of the rotating electric machine 1 or the reduction mechanism 34 in terms of its positioning region in the first direction X.

[0098] According to this embodiment, the arrangement areas of the rotating electric machine 1, the inverter device 90A, and the output gear 30, which is arranged coaxially with the first output member 61, overlap in an axial view, thereby reducing the overall size of the vehicle drive unit 100 in the second direction Y. That is, by effectively utilizing the space that overlaps with the output gear 30 in an axial view, the rotating electric machine 1 and the inverter device 90A can be arranged closer to the first direction X. This also reduces the overall size of the vehicle drive unit 100 in the first direction X. Furthermore, by arranging the rotating electric machine 1 and the inverter device 90A closer to the first direction X, the wiring for the electrical connection between the rotating electric machine 1 and the inverter device 90A becomes easier to route.

[0099] In this way, according to this embodiment, the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y can be reduced, that is, the dimensions of the vehicle drive unit 100 in the axial view can be reduced. This improves the mountability of the vehicle drive unit 100 on the vehicle VC.

[0100] Incidentally, in this embodiment, as described above, the mounting space around the second axis C2 (mounting space for other members) gradually increases from the second axial side A2 to the first axial side A1. Therefore, the dimension of the inverter case portion 24A of the inverter device 90A in the second direction Y (the dimension of the second inverter housing chamber S42 in the second direction Y) can also be gradually increased from the second axial side A2 to the first axial side A1 without changing the position of the inverter case portion 24A at the furthest point on the first axial side Y1, as shown in Figure 9. In this case, the various components of the inverter device 90A may be arranged in the inverter case portion 24A in such a manner that the dimension of the component located on the first axial side A1 is smaller than that of the component located on the second axial side A2.

[0101] Specifically, as shown in Figure 9, the inverter case section 24A has a differential-side case section 241A that overlaps with the differential case section 50 in a second-direction view, and an intermediate-side case section 242A that overlaps with the first output member 61 in a second-direction view, and the intermediate-side case section 242A may be set to have a larger dimension in the second direction Y than the differential-side case section 241A. In this case, various components of the inverter device 90A, which may have significant differences in the dimension in the second direction Y, can be efficiently arranged. Note that the differential-side case section 241A and the intermediate-side case section 242A may be in internal communication.

[0102] In this embodiment, as a preferred example, as shown in Figure 9, a power module PM is arranged in the differential side case portion 241A, and a smoothing capacitor CM is arranged in the intermediate side case portion 242A. Such an arrangement is suitable when the required mounting space thickness (height) of the smoothing capacitor CM is greater than that of the power module PM. In the example shown in Figure 8, the inverter case portion 24A is provided with a bus bar B2 extending in the axial direction A on the first side X1 of the first direction of the power module PM and the smoothing capacitor CM.

[0103] In this embodiment, a high-voltage connector (not shown) for receiving power from the battery BA (see Figure 1) may be located on the first side Y1 in the second direction of the reduction mechanism 34. In this case, the connector CN1 can be positioned using the dead space that is easily formed on the first side Y1 in the second direction of the reduction mechanism 34 (a dead space that does not affect the size of the vehicle drive unit 100 in the second direction Y). Alternatively, the high-voltage connector may be located on the second side X2 in the first direction relative to the power module PM or smoothing capacitor CM, together with some components of the inverter device 90A (relatively small components other than the power module PM or smoothing capacitor CM, such as a filter). In this case, these components may protrude further into the second side X2 in the first direction than the position of the transmission mechanism case 22 furthest in the second side X2 in the first direction (the end position of the second side X2 in the first direction).

[0104] Furthermore, in this embodiment, as shown in Figure 10, the control board SB of the inverter device 90A may be positioned on the first side Y1 of the second direction of the output gear 30. That is, the control board SB may be positioned on the first side Y1 of the second direction of the output gear 30 in a manner that overlaps with the output gear 30 when viewed from the second direction. In this case, the control board SB may be positioned in a direction where the second direction Y is the normal direction. In this case, since the dimension of the control board SB in the second direction Y is relatively small, it may still be possible to position the inverter case portion 24A (inverter cover member 203A) on the second side Y2 of the second direction rather than the position on the differential cover member 202 that is closest to the first side Y1 of the second direction.

[0105] Next, with reference to Figures 11 and 12, the oil lubrication structure and cooling structure of the vehicle drive unit 100 in this embodiment will be outlined.

[0106] Figure 11 is a schematic diagram showing the vehicle drive unit 100A in an axial view from the first axial side A1, with a portion shown in perspective to allow the interior to be seen. Figure 12 is a schematic diagram showing the interior of the vehicle drive unit 100A in an axial view from the first axial side A1, showing a different part offset in the axial direction A with line 800 as the boundary. In Figure 12, the outer circumference of the output gear 30 is shown by a dashed line to explain the positional relationship.

[0107] In this embodiment, the rotating electric machine 1 may be oil-cooled, water-cooled, or a combination thereof. In the case of oil cooling, the inverter housing chamber S4 may be sealed in such a manner that it does not fluidly communicate with the motor housing chamber S1, the transmission mechanism housing chamber S2, and the output shaft housing chamber S3. In this case, a partition wall may not be formed between the motor housing chamber S1 and the output shaft housing chamber S3, and they may communicate with each other. In this case, the wiring connection portion 600 between the rotating electric machine 1 and the inverter device 90A may be provided in such a manner that it penetrates an axial partition wall portion (not shown) in the direction A that separates the motor housing chamber S1 or the output shaft housing chamber S3 from the inverter housing chamber S4. The wiring connection portion 600 may be in the form of a high-voltage connector or terminal block for connecting the rotating electric machine 1 and the power module PM of the inverter device 90A.

[0108] On the other hand, in the case of a water-cooled system, the inverter housing chamber S4 may be fluidly connected to the motor housing chamber S1, etc. In this case, for example, as shown in Figure 6, part or all of the wall separating the inverter housing chamber S4 and the motor housing chamber S1 may be eliminated, making it easier to route the wiring between the rotating electric machine 1 and the inverter device 90A. For example, in the examples shown in Figures 11 and 12, the rotating electric machine 1 is water-cooled, and the wiring connection part 600 between the rotating electric machine 1 and the inverter device 90A is provided in a manner that communicates with both the inverter housing chamber S4 and the motor housing chamber S1. In this case, as shown in Figure 11, a partition wall 28 may be formed between the motor housing chamber S1 and the output shaft housing chamber S3.

[0109] Furthermore, in the examples shown in Figures 11 and 12, a cooling water channel (hereinafter referred to as "motor cooling water channel 129A" ​​for distinction) is formed around the outer circumference of the stator core 12. In this case, the motor cooling water channel 129A may be formed in the case member 200, or it may be formed in another support member (a component of the motor case portion 21 of case 2A) 204A that is coupled to the case member 200. In this case, the support member 204A may be cylindrical in shape and may be integrated with the radially outer side of the stator core 12 by shrink fitting, casting, etc. Also in this case, the support member 204A may be integrated with the case member 200 by fastening, etc. Furthermore, if the rotor shaft 15 is hollow with an axial hole, the motor cooling water channel 129A may communicate with the axial hole of the rotor shaft 15.

[0110] In this embodiment, the inverter case portion 24A of case 2A has a cooling water passage (hereinafter referred to as "inverter cooling water passage 99A" for distinguishing purposes) through which cooling water for cooling the inverter device 90A passes.

[0111] The inverter cooling water channel 99A may be positioned in a region that overlaps with the output gear 30 in an axial view. In this case, an efficient arrangement (layout) of the inverter cooling water channel 99A can be achieved without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the inverter cooling water channel 99A.

[0112] The inverter cooling water channel 99A may have a channel portion that extends over an area overlapping with the entire or a part of the smoothing capacitor CM in a second view, but preferably it may extend over an area overlapping with the entire or a part of the power module PM in a second view without having a channel portion that extends over an area overlapping with the entire or a part of the smoothing capacitor CM in a second view. That is, the inverter cooling water channel 99A may be located on the second axial side A2 of the smoothing capacitor CM. In this case, the inverter cooling water channel 99A may be formed in the partition wall portion 28 of the case 2A that separates the inverter housing chamber S4 and the transmission mechanism housing chamber S2.

[0113] In this embodiment, the smoothing capacitor CM is positioned in a region that overlaps with the first output member 61 in a second view, and is positioned relatively far from the rotating electric machine 1, which is the main heat source other than the heat source in the inverter case 24A. Therefore, even if the inverter cooling water channel 99A is positioned so that it does not overlap with the smoothing capacitor CM in a second view, the smoothing capacitor CM can be properly cooled via the inverter case 24A, which is cooled by the cooling water in the inverter cooling water channel 99A. Thus, by positioning the inverter cooling water channel 99A so that it does not overlap with the smoothing capacitor CM in a second view, an efficient arrangement of the inverter cooling water channel 99A can be achieved without significantly reducing the cooling performance of the smoothing capacitor CM.

[0114] Furthermore, the inverter cooling water passage 99A may have an inlet portion 991A and a chamber portion 992A in a region where the distance from the differential case portion 50 in the first direction X is relatively large (for example, in an axial view, the region Y2 on the second side of the second direction from the first output member 61). The inlet portion 991A is the part into which cooling water discharged from a water pump (not shown) (see water pump W / P in Figure 7) is introduced.

[0115] The chamber section 992A may extend axially along the entire axial length A of the inverter cooling water channel 99A. The chamber section 992A has a significantly larger cross-sectional area (and volume) than the inlet section 991A, and significantly less resistance than the flow path portion in contact with the power module PM (e.g., the flow path around the fins). Therefore, by providing such a chamber section 992A adjacent to the inlet section 991A from the downstream side, the required flow rate of cooling water introduced into the inverter cooling water channel 99A can be effectively secured. A chamber chamber 993A similar to the chamber section 992A may be provided downstream of the flow path portion in contact with the power module PM in the inverter cooling water channel 99A.

[0116] Furthermore, if the motor cooling water passage 129A described above is provided, the inverter cooling water passage 99A may be in communication with the motor cooling water passage 129A. In this case, the inverter cooling water passage 99A may be located upstream of the motor cooling water passage 129A, and in this case, the motor cooling water passage 129A may have an outlet (not shown) for returning cooling water to a water pump (not shown). The outlet (not shown), together with the inlet 991A described above, may be located in a region that overlaps with the output gear 30 in an axial view. In this case, an efficient arrangement of the inverter cooling water passage 99A can be achieved without increasing the overall size of the vehicle drive unit 100 in the first direction X and the second direction Y due to the inverter cooling water passage 99A.

[0117] Furthermore, if the motor cooling water passage 129A described above is provided, a water passage for connecting the inverter cooling water passage 99A and the motor cooling water passage 129A (hereinafter also referred to as the "connecting water passage 1290A") may be formed in the case 2A. That is, the connecting water passage 1290A may be realized as an internal case water passage, similar to the motor cooling water passage 129A and the inverter cooling water passage 99A. The connecting water passage 1290A may extend in the axial direction A and the first direction X. Alternatively, the connecting water passage 1290A may extend in the axial direction A, the first direction X, and the second direction Y. In this case, the connecting water passage 1290A may be formed in the part of the case 2A that forms the motor case portion 21 and the transmission mechanism case portion 22 or the output shaft case portion 23. Also, the connecting water passage 1290A may be located above the first output member 61 in an axial view and in a region that overlaps with the output gear 30 in an axial view.

[0118] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above. In addition, the effects related to the dependent claims among the effects of each embodiment are additional effects that are distinct from the higher-level concepts (independent claims).

[0119] For example, in the above-described embodiment 1, the first output member 61 is positioned between the first direction X of the rotating electric machine 1 and the inverter device 90 at the second direction Y where both the rotating electric machine 1 and the inverter device 90 are located, but it is not limited to this. For example, the inverter device 90 may be positioned on the second axial side A2 of the first output member 61. In this case, the differential case portion 50 may be positioned between the first direction X of the rotating electric machine 1 or the reduction mechanism 34 and the inverter device 90 at the second direction Y where both the rotating electric machine 1 or the reduction mechanism 34 and the inverter device 90 are located. Even in such a case, the first output member 61 may be positioned between the first direction X of the rotating electric machine 1 and the inverter device 90 at the second direction Y where both the rotating electric machine 1 and the inverter device 90 are located in an axial view.

[0120] Furthermore, in the above-described embodiment 1 (and similarly in embodiment 2), the inverter case portion 24 extends axially A around the differential case portion 50 and the first output member 61 (in a manner opposite to the differential case portion 50 and the first output member 61 in the first direction X and the second direction Y), but is not limited to this. For example, in the above-described embodiment 1, the inverter case portion 24 may extend axially A around the differential case portion 50 of the differential case portion 50 and the first output member 61 (in a manner opposite to the differential case portion 50 in the first direction X and the second direction Y). Also, in the above-described embodiment 2, the inverter case portion 24A may extend axially A around the differential case portion 50 of the differential case portion 50 and the first output member 61 (in a manner opposite to the differential case portion 50 in the second direction Y). [Explanation of symbols]

[0121] 1... Rotating electric machine, 3... Transmission mechanism, 5... Differential gear mechanism, 50... Differential case section, 51... First side gear, 15... Rotor shaft, 2, 2A... Case, 21... Motor case section (first case section), 22... Transmission mechanism case section (second case section), 23... Output shaft case section, 24, 24A... Inverter case section (third case section), 201... Motor cover member (first cover member), 202... Differential cover member (second cover member), 6... Output member, 61... First output member, 30... Output gear, 90, 90A... Inverter device, 99, 99A... Inverter cooling water channel (second cooling water channel), 129, 129A... Motor cooling water channel (first cooling water channel), S1... Motor housing chamber (first housing chamber), S3... Output shaft housing chamber (second housing chamber), S4... Inverter housing chamber (third housing chamber), C1... First shaft (axis), C2... Second shaft (axis), BA... Battery, A... Axial direction, X... First direction, Y... Second direction, PM... Power module, CM... Smoothing capacitor, SB... Control board

Claims

1. A rotating electric machine having a rotor and a stator, A first output member is one of a pair of output members that are driven and connected to each of the wheels, A transmission mechanism for transmitting driving force between the rotating electric machine and a pair of output members, An inverter device that receives power from a battery and supplies power to the rotating electric machine, A case having a first case section for housing the rotating electric machine, a second case section for housing the transmission mechanism, and a third case section for housing the inverter device, The rotor is fixed so as not to rotate and comprises a rotor shaft supported by the case, The rotating electric machine and the pair of output members are arranged on two axes that are parallel to each other. The transmission mechanism includes an output gear, which is driven and connected to at least one of the pair of output members, coaxially with the pair of output members. The output gear is arranged so as to overlap with the rotating electric machine and the inverter device in an axial view along the axial direction. The inverter device is arranged so as to overlap with the transmission mechanism or the first output member when viewed in the vertical direction. The pair of output members are arranged so as to overlap with the axis of the rotor shaft when viewed in the direction along the vehicle's longitudinal direction, and the inverter device is positioned below the uppermost position of the first case in the vertical direction. The inverter device is arranged such that a plane passing through both the axis of the rotating electric machine and the axis of the output gear passes through the inverter device.

2. A rotating electric machine having a rotor and a stator, A first output member is one of a pair of output members that are driven and connected to each of the wheels, A transmission mechanism for transmitting driving force between the rotating electric machine and a pair of output members, An inverter device that receives power from a battery and supplies power to the rotating electric machine, A case having a first case section for housing the rotating electric machine, a second case section for housing the transmission mechanism, and a third case section for housing the inverter device, The rotor is fixed so as not to rotate and comprises a rotor shaft supported by the case, The rotating electric machine and the pair of output members are arranged on two axes that are parallel to each other. The transmission mechanism includes an output gear, which is driven and connected to at least one of the pair of output members, coaxially with the pair of output members. The output gear is arranged so as to overlap with the rotating electric machine and the inverter device in an axial view along the axial direction. The inverter device is arranged so as to overlap with the transmission mechanism or the first output member when viewed in the vertical direction. The inverter device includes a power module and a smoothing capacitor, The power module and the smoothing capacitor are arranged side by side along the axial direction. The transmission mechanism includes a differential gear mechanism, The differential gear mechanism comprises a differential case portion that rotates integrally with the output gear, and a first side gear that is driven and connected to the first output member. A vehicle drive device wherein the power module overlaps with the differential case portion when viewed in the vertical direction, and the smoothing capacitor overlaps with the first output member when viewed in the vertical direction.

3. A rotating electric machine having a rotor and a stator, A first output member is one of a pair of output members that are driven and connected to each of the wheels, A transmission mechanism for transmitting driving force between the rotating electric machine and a pair of output members, An inverter device that receives power from a battery and supplies power to the rotating electric machine, A case having a first case section for housing the rotating electric machine, a second case section for housing the transmission mechanism, and a third case section for housing the inverter device, The rotor is fixed so as not to rotate and comprises a rotor shaft supported by the case, The rotating electric machine and the pair of output members are arranged on two axes that are parallel to each other. The transmission mechanism includes an output gear, which is driven and connected to at least one of the pair of output members, coaxially with the pair of output members. The output gear is arranged so as to overlap with the rotating electric machine and the inverter device in an axial view along the axial direction. The inverter device is arranged so as to overlap with the transmission mechanism or the first output member when viewed in the vertical direction. The pair of output members are arranged so as to overlap with the axis of the rotor shaft when viewed in the direction along the vehicle's longitudinal direction, and the inverter device is positioned below the uppermost position of the first case in the vertical direction. A vehicle drive system in which the vertical arrangement regions of the rotating electric machine, the inverter device, and the output gear overlap.

4. A rotating electric machine having a rotor and a stator, A first output member is one of a pair of output members that are driven and connected to each of the wheels, A transmission mechanism for transmitting driving force between the rotating electric machine and a pair of output members, An inverter device that receives power from a battery and supplies power to the rotating electric machine, A case having a first case section for housing the rotating electric machine, a second case section for housing the transmission mechanism, and a third case section for housing the inverter device, The rotor is fixed so as not to rotate and comprises a rotor shaft supported by the case, The rotating electric machine and the pair of output members are arranged on two axes that are parallel to each other. The transmission mechanism includes an output gear, which is driven and connected to at least one of the pair of output members, coaxially with the pair of output members. The output gear is arranged so as to overlap with the rotating electric machine and the inverter device in an axial view along the axial direction. The inverter device is arranged so as to overlap with the transmission mechanism or the first output member when viewed in the vertical direction. The pair of output members are arranged so as to overlap with the axis of the rotor shaft when viewed in the direction along the vehicle's longitudinal direction, and the inverter device is positioned below the uppermost position of the first case in the vertical direction. The shaft of the output gear is positioned between the rotating electric machine and the inverter device in the longitudinal direction of the vehicle, in a vehicle drive system.

5. The case further houses the first output member, The vehicle drive device according to any one of claims 1 to 4, wherein the first housing chamber in the case for housing the rotating electric machine communicates with the second housing chamber in the case for housing the first output member.

6. The vehicle drive device according to any one of claims 1 to 4, wherein the inverter device is positioned in the longitudinal direction of the vehicle closer to the rotating electric machine than the end of the second case portion opposite to the rotating electric machine.

7. The vehicle drive device according to claim 1, 3, or 4, wherein the third housing chamber for housing the inverter device in the case has a region in the axial direction that is larger in the vertical direction on the side closer to the rotating electric machine than on the side further away, and extends in the longitudinal direction of the vehicle and in the axial direction.

8. The inverter device includes a power module and a smoothing capacitor, The vehicle drive device according to claim 7, wherein the smoothing capacitor is positioned closer to the rotating electric machine in the axial direction than the power module.

9. The vehicle drive device according to claim 2, wherein the third housing chamber for housing the inverter device in the case has a region in the axial direction that is larger in the vertical direction on the side closer to the rotating electric machine than on the side further away, and extends in the longitudinal direction of the vehicle and in the axial direction.

10. The vehicle drive device according to claim 9, wherein the smoothing capacitor is located closer to the rotating electric machine in the axial direction than the power module.

11. The inverter device further includes a control board, The control board overlaps the output gear when viewed in the vertical direction, according to any one of claims 1 to 4.

12. The inverter device includes a power module, The case is formed with a first cooling water channel through which cooling water for cooling the rotating electric machine passes, and a second cooling water channel that communicates with the first cooling water channel and extends to an area that overlaps with the power module when viewed in the vertical direction. The vehicle drive device according to claim 1, 3, or 4, wherein the second cooling water passage overlaps with the output gear in the axial view.

13. The case is provided with a first cooling water channel through which cooling water for cooling the rotating electric machine passes, and a second cooling water channel that communicates with the first cooling water channel and extends to an area that overlaps with the power module when viewed in the vertical direction, The vehicle drive device according to claim 2, wherein the second cooling water passage overlaps with the output gear in the axial view.

14. The first case portion is arranged on one side in the axial direction relative to the second case portion, The first case portion has a first cover member that covers the opening on one side in the axial direction, The second case portion has a second cover member that covers the opening on the opposite side in the axial direction from the one side, The vehicle drive device according to any one of claims 1 to 4, wherein the inverter device extends in the axial direction between the first case portion and the second cover member.

15. The vehicle drive device according to any one of claims 1 to 4, wherein the uppermost position and the lowermost position in the case are located in the first case portion.

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