Vehicle drive systems

Abstract

To efficiently secure the necessary capacity of a breather chamber while preventing the increasing size of a case.SOLUTION: A disclosed drive unit for a vehicle comprises: a transfer mechanism that transfers a driving force from a driving source to a wheel; a case that forms a storage chamber for housing the driving source and / or the transfer mechanism with oil; and a breather that is provided in the case. The breather has a case-side opening that is opened in the storage chamber, an atmospheric opening that is opened in atmospheric air, and a breather chamber that communicates with the case-side opening and the atmospheric opening. The breather chamber includes a first breather chamber that is formed in the case, and a second breather chamber that is formed of an insulation member for being attached to the case in the storage chamber.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In a vehicle drive device, a technology is known in which a breather chamber communicated with the outside of a case is partitioned into a motor housing chamber of the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art as described above, the breather recess (breather chamber) is configured to be closed by a flat breather plate. When increasing the volume of the breather chamber, there is a risk of causing an increase in the size of the case along with an increase in the size of the breather recess.

[0005] Therefore, on one side, an object of the present disclosure is to efficiently secure the necessary volume of the breather chamber while preventing an increase in the size of the case.

Means for Solving the Problems

[0006] On one side, a transmission mechanism that transmits the driving force from the drive source to the wheels, a case that forms a housing chamber for housing at least one of the drive source and the transmission mechanism together with oil, and a breather provided on the case are provided, where the breather has a case - side opening that opens into the housing chamber, an atmosphere opening that opens to the atmosphere, It has a case-side opening and a breather chamber that communicates with the atmospheric opening, The aforementioned breather chamber is A first breather chamber formed in the aforementioned case, A vehicle drive system is provided, which includes a second breather chamber formed by an insulating member attached to the case. [Effects of the Invention]

[0007] In one respect, this disclosure makes it possible to efficiently secure the necessary volume for the breather chamber while preventing the case from becoming too large. [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 a vehicle drive system. [Figure 2A] This is a skeleton diagram showing a vehicle drive system. [Figure 3] This is a schematic top view showing a vehicle drive system according to Example 1. [Figure 3A] This is a schematic side view showing the vehicle drive unit according to Example 1 as viewed from the axial first side A1. [Figure 4] This is a perspective view of the channel forming member. [Figure 5] This is an enlarged view of section Q6 in Figure 2. [Figure 6] This is a schematic side view showing the vehicle drive unit according to Example 1 as viewed from the axial second side A2. [Figure 7] This is a schematic cross-sectional view of a vehicle drive system through a breather in a vertical plane according to Example 1. [Figure 8] This is a schematic cross-sectional view of a vehicle drive system through a breather in a vertical plane according to Example 2. [Figure 9] This is a schematic side view showing the bulkhead in the vehicle drive system according to Embodiment 2, viewed from the axial first side A1. [Figure 10] This is an enlarged view of section Q10 in Figure 8. [Figure 11] It is a perspective view of the insulating member in a single-piece state as viewed from the first axial side A1. [Figure 12] It is an exploded perspective view of the insulating member in the same view as FIG. 11. [Figure 13] It is a perspective view of the insulating member in a single-piece state as viewed from the second axial side A2. [Figure 14] It is a schematic cross-sectional view of a vehicle drive device by a vertical plane passing through a breather according to a comparative example.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes in the drawings may be exaggerated partially for the convenience of explanation. Also, in the drawings, for the sake of clarity, only some of the parts having the same attribute may be labeled with reference numerals.

[0010] In the following description, the Y direction (see FIG. 3A etc.) corresponds to 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 its usage state orientation. And the Y1 side and the Y2 side correspond to the upper side and the lower side along the Y direction. Note that the vertical direction does not necessarily have to be parallel to the vertical direction, and it is sufficient to mainly have a vertical direction component. 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. Also, terms regarding the dimensions, arrangement directions, arrangement positions, etc. of the respective members are concepts including states having differences due to errors (errors allowable in manufacturing). The A direction (see FIG. 2 etc.) corresponds to the axial direction, and in FIG. 2 etc., the A1 side and the A2 side along the A direction are defined. Also, the X direction (see FIG. 3 etc.) is a direction orthogonal to both the A direction and the Y direction, and in FIG. 3 etc., the X1 side and the X2 side along the X direction are defined.

[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 addition, in this specification, "communication" refers to a state in which two spatial elements are in fluid communication with each other. That is, it refers to a state in which fluid can flow back and forth between two spatial elements. At this time, the two spatial elements may communicate directly or indirectly (that is, via other spatial elements).

[0013] In this specification, "rotating electrical machine" is used as a concept that includes any of a motor (electric motor), a generator (generator), and a motor-generator that performs the functions of both a motor and a generator as required. 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 part of a 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.

[0014] FIG. 1 is a schematic top view showing the mounting state of the vehicle drive device 100 in the vehicle VC. FIG. 2 is a cross-sectional view of the vehicle drive device 100. FIG. 2A is a skeleton view showing the vehicle drive device 100.

[0015] As schematically shown in Figure 2A, the vehicle drive unit 100 comprises a rotating electric machine 1, a pair of output members 6 that are driven and connected to a pair of wheels W (see Figure 1), and a transmission mechanism 3 that transmits driving force between the rotating electric machine 1 and the pair of output members 6. The vehicle drive unit 100 further comprises a case 2 that houses the rotating electric machine 1. The case 2 also houses the pair of output members 6 and the transmission mechanism 3. In a modified example, the case 2 may house only one of the pair of output members 6 (for example, the first output member 61). Furthermore, the vehicle drive unit 100 can be applied to any vehicle having a rotating electric machine 1, such as electric vehicles or hybrid vehicles, and the drive system can be any vehicle, such as front-wheel drive or rear-wheel drive. Also, the drive source may be only an engine (internal combustion engine).

[0016] 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. The first output member 61 may be in the form of an intermediate shaft. The first output member 61 is rotatably supported on the second axial side A2 via bearing BR1 relative to the case 2, and on the first axial side A1 via bearing BR2 relative to the case 2. In this embodiment, bearings BR1 and BR2 are ball bearings as an example, but other forms may also be used.

[0017] The vehicle drive unit 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 unit 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 a three-phase AC.

[0018] As shown in Figure 2, the rotating electric machine 1 and the pair of output members 6 are arranged on two parallel axes (specifically, a first axis C1 and a 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 a 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 (ring 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).

[0019] The rotating electric machine 1 is, for example, an inner rotor type. In the rotating electric machine 1, a rotor 14 that can rotate around the first axis C1 is arranged radially inside the stator 11 (see Figure 2).

[0020] The rotor shaft 15 of the rotor 14 is rotatably supported relative to the case 2 via bearing BR3 on the second axial side A2, and via bearing BR4 on the first axial side A1. In this embodiment, bearings BR3 and BR4 are ball bearings as an example, but other forms may be used. In the example shown in Figure 2, the rotor shaft 15 has an axial oil passage 15a and radial ejection holes 15b, and during rotation, centrifugal force can eject oil from the axial oil passage 15a toward the coil end 13 from each of the radial ejection holes 15b.

[0021] 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.

[0022] In this embodiment, the reduction mechanism 34 is arranged coaxially with the rotating electric machine 1 (i.e., on the first axis C1) and is driven and connected to the rotating electric machine 1. In this embodiment, as an example, the rotor 14 of the rotating electric machine 1 rotates integrally with the input member 16 together with the sun gear 341 of the reduction mechanism 34.

[0023] 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. In the example shown in Figure 2, the differential gear mechanism 5 distributes the rotation of the output gear 30 to the first side gear 51 and the second side gear 52. 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 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.

[0024] Next, the configuration of Case 2 will be explained in detail with reference to Figures 2 and 3.

[0025] Figure 3 is a schematic top view showing the vehicle drive unit 100 according to this embodiment. In Figure 3, the inverter cover member 203 at the top of the inverter case 24 is omitted from the illustration so that the elements arranged inside the inverter case 24 can be seen.

[0026] 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).

[0027] 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 70. 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.

[0028] The motor case portion 21 has a cylindrical shape corresponding to the outer shape of the rotating electric machine 1. However, the motor case portion 21 does not need to have a completely closed cylindrical outer circumference. For example, the motor housing chamber S1 and the output shaft housing chamber S3 may be in communication, in which case a wall portion (partition wall portion) does not need to be formed on the side of the motor case portion 21 facing the output shaft housing chamber S3.

[0029] The transmission mechanism case 22 is provided on the second axial side A2 relative to the motor case 21 and the output shaft case 23. The output shaft case 23 is provided on the X-direction X2 side relative to the motor case 21. The inverter case 24 is provided above the transmission mechanism case 22 and the output shaft case 23. Details of the inverter case 24 will be described later.

[0030] 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 secured between the first output member 61 and surrounding parts can be reduced. However, in a modified example, the first output member 61 may be provided outside the case 2.

[0031] 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.

[0032] 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). In this embodiment, since oil is supplied to the motor housing chamber S1, the motor housing chamber S1 and the inverter housing chamber S4 may be separated.

[0033] 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.

[0034] 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.

[0035] The case member 200 has an axial opening on the first axial side A1 and an axial opening on the second axial side A2.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The inverter device 70 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.

[0040] As described above, the inverter device 70 is housed in the inverter housing chamber S4 of the inverter case 24. The inverter device 70 receives power from the battery BA (see Figure 1) and supplies power to the rotating electric machine 1. The battery BA is optional, but may be a high-voltage battery with a relatively high rated voltage, and may be a lithium-ion battery or the like. The inverter device 70 mainly includes a power module PM, a smoothing capacitor CM, and a busbar structure 72. The inverter device 70 may further include a control board (not shown) on which a control device for controlling the inverter circuit is mounted. The busbar structure 72 is placed between the rotating electric machine 1 and the power module PM and electrically connects the two.

[0041] In this embodiment, the inverter case 24 is arranged so as to overlap the first axis C1 and the second axis C2 when viewed from above (viewed in the second direction Y, the same applies hereinafter).

[0042] The inverter housing chamber S4 includes a first housing section S41, a second housing section S42, and a third housing section S43. In a top view, the inverter housing chamber S4 has an L-shape, as shown in Figure 3. Specifically, if the X-direction center is defined as the space between the first axis C1 and the second axis C2 in the X-direction, the inverter housing chamber S4 extends on both sides in the X-direction with respect to the X-direction center, straddling the X-direction center. Also, if the A-direction center is defined as the space between the rotating electric machine 1 and the reduction mechanism 34 in the A-direction, the inverter housing chamber S4 extends on both sides in the A-direction center, straddling the A-direction center on the second side X2 of the first direction. On the other hand, in the first side X1 of the first direction, the inverter housing chamber S4 extends only on the axial second side A2 beyond the A-direction center.

[0043] More specifically, the first housing section S41, the second housing section S42, and the third housing section S43 are arranged in an L-shape overall when viewed from above, as shown in Figure 3. In this arrangement, the first housing section S41 overlaps the first axis C1 (i.e., the reduction mechanism 34) on the second axial side A2 when viewed from above, and overlaps the rotating electric machine 1 when viewed in the axial direction A. The second housing section S42 overlaps the second axis C2 when viewed from above, and overlaps the rotating electric machine 1 when viewed in the first direction X. The third housing section S43 is adjacent to the first housing section S41 and the second housing section S42, and overlaps the second axis C2 when viewed from above. The third housing section S43 may be integrally connected to the first housing section S41 and the second housing section S42.

[0044] The first housing section S41, the second housing section S42, and the third housing section S43 are positioned above a plane (not shown) that includes the first axis C1, which is the axis of rotation of the rotating electric machine 1, and the second axis C2, which is the axis of the output member 6. In this embodiment, as described above, 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, so the plane (not shown) that includes the first axis C1 and the second axis C2 is a plane close to the horizontal plane.

[0045] In this embodiment, the busbar structure 72, a component of the inverter device 70, is arranged in the first housing section S41, the smoothing capacitor CM is arranged in the second housing section S42, and the power module PM is arranged in the third housing section S43. In this case, the busbar structure 72 and the power module PM are adjacent in the first direction X, and the power module PM and the smoothing capacitor CM are adjacent in the axial direction A. Note that the boundaries of the first housing section S41, the second housing section S42, and the third housing section S43 do not need to be strict; for example, a part of the first axial side A1 of the power module PM may be arranged in the second housing section S42, or a part of the first axial side X1 of the power module PM may be arranged in the first housing section S41.

[0046] Next, with reference to Figures 3A and 4, the water-cooling structure of the rotating electric machine 1 according to this embodiment and its related components (such as the flow path forming member 90) will be described.

[0047] Figure 3A is a schematic side view showing the vehicle drive unit according to this embodiment as viewed from the axial first side A1. In Figure 3A, the motor cover member 201 is omitted from the illustration so that the state inside the motor housing chamber S1 can be seen. Also in Figure 3A, the inverter device 70 inside the inverter case 24 is schematically shown with a dotted line. Figure 4 is a perspective view of the flow path forming member 90.

[0048] The water-cooling structure of the rotating electric machine 1 according to this embodiment is a structure for cooling the rotating electric machine 1 with cooling water. The cooling water may be water containing, for example, LLC (Long Life Coolant), and may be circulated by a water pump (not shown). A heat dissipation part such as a radiator (not shown) may be provided in the cooling water circulation path. In addition to cooling the rotating electric machine 1, the cooling water may also be used to cool other components, such as an inverter device 70 that is electrically connected to the rotating electric machine 1.

[0049] The water-cooling structure of the rotating electric machine 1 according to this embodiment includes a refrigerant supply unit 40, a refrigerant discharge unit 42, and a flow path forming member 90.

[0050] The refrigerant supply unit 40 communicates with the discharge side of, for example, a water pump (not shown) and supplies cooling water to the refrigerant flow path 300 formed by the flow path forming member 90.

[0051] The refrigerant discharge section 42 communicates with the suction side of, for example, a water pump (not shown), and supplies (discharges) cooling water from the refrigerant flow path 300 formed by the flow path forming member 90 to the water pump (not shown).

[0052] The refrigerant supply unit 40 and the refrigerant discharge unit 42 may be provided above and below the first output member 61, respectively. In this case, the space around the first output member 61 can be effectively utilized to accommodate the refrigerant supply unit 40 and the refrigerant discharge unit 42.

[0053] As shown in Figure 4, the flow path forming member 90 has a cylindrical shape with an inner circumferential surface radially opposite the outer circumferential surface of the rotating electric machine 1. The flow path forming member 90 forms a refrigerant flow path 300 around the rotating electric machine 1. In the example shown in Figure 4, the refrigerant flow path 300 has multiple flow path sections SC1 to SC4 in the circumferential direction, but the configuration of the refrigerant flow path 300 is arbitrary.

[0054] The flow path forming member 90 may be made of a material with good thermal conductivity, such as aluminum. In this embodiment, as an example, the flow path forming member 90 is fitted to the stator core 12 of the stator 11 by shrink fitting, for example. In other embodiments, the flow path forming member 90 may be integrally formed with the stator core 12 by casting or the like.

[0055] In this embodiment, the flow path forming member 90 is, as an example, in the form of an inner case fastened to the case 2, as shown in Figure 3A. In this case, the flow path forming member 90 may have a plurality of fastening portions 500 on one axial end, as shown in Figure 3A. The plurality of fastening portions 500 are fastened to the case 2 by bolts (not shown) (see bolt holes BT4). In a modified example, the flow path forming member 90 may be formed as part of the case 2.

[0056] The flow path forming member 90 is inserted into the cylindrical space of the case 2. At this time, the outer circumferential surface of the flow path forming member 90 faces radially with respect to the inner circumferential surface of the case 2 (the inner circumferential surface that defines the multiple fastening portions 500). Hereafter, the inner circumferential surface of the case 2 that surrounds the flow path forming member 90 in this manner will also be referred to as the "flow path forming surface 209 of the case 2" (see Figure 5). The inner diameter of the flow path forming surface 209 of the case 2 may be a constant value that is larger than the basic outer diameter of the stator core 12 by the basic thickness of the flow path forming member 90.

[0057] The flow path forming member 90 cooperates with the flow path forming surface 209 of the case 2 to form a refrigerant flow path 300. Specifically, the refrigerant flow path 300 is formed radially between the outer circumferential surface of the flow path forming member 90 and the flow path forming surface 209 of the case 2.

[0058] The refrigerant flow path 300 may extend circumferentially so that cooling water flows circumferentially throughout the entire circumferential direction. The refrigerant flow path 300 may also be formed so as to be radially opposite the outer circumferential surface of the stator core 12 over the entire axial direction of the stator core 12 of the rotating electric machine 1. The refrigerant flow path 300 is closed at both axial ends. For example, between the flow path forming member 90 and the flow path forming surface 209 of the case 2, a sealing member 97 (see Figure 5) may be provided over the entire circumferential direction at both axial ends of the flow path forming member 90.

[0059] Next, with reference to Figures 5 and 6, the oil passage structure of the vehicle drive unit 100 according to this embodiment and its related components will be described. Unless otherwise specified, the various oil passages in the oil passage structure described below are formed by case 2. In this specification, the various oil passages formed by case 2 include not only oil passages formed by case 2 alone, but also oil passages formed by a combination of case 2 and other components (components other than case 2). Furthermore, a housing chamber such as the output shaft housing chamber S3 also constitutes an oil passage.

[0060] Figure 5 is a cross-sectional view taken from a plane passing through the second axis C2 and the Y direction, and is an enlarged view of part Q6 in Figure 2 (a cross-sectional view passing through the output shaft housing chamber S3). Figure 6 is a schematic side view showing the vehicle drive unit 100 according to this embodiment as viewed from the axial second side A2.

[0061] As described above, the transmission mechanism housing chamber S2 and the output shaft housing chamber S3 overlap the second shaft C2 in a top view and are adjacent in the axial direction. Furthermore, since the transmission mechanism housing chamber S2 extends in the X direction in a manner that accommodates the reduction mechanism 34 and the differential gear mechanism 5, the transmission mechanism housing chamber S2 and the output shaft housing chamber S3 extend in an L-shape in a top view. Hereinafter, the portion of the transmission mechanism housing chamber S2 that accommodates the reduction mechanism 34 will also be referred to as the "reduction mechanism housing chamber S21," and the portion that accommodates the differential gear mechanism 5 will also be referred to as the "differential gear housing chamber S22."

[0062] The output shaft case portion 23 extends around the second shaft C2 along the extending direction (i.e., axial direction) of the first output member 61. The output shaft case portion 23 may take the form of a peripheral wall portion that forms the space (output shaft housing chamber S3) around the first output member 61. In this case, the output shaft case portion 23 extends radially outward (towards the X direction X2) of the rotating electric machine 1 and may also form a part of the motor case portion 21.

[0063] In this embodiment, the output shaft housing chamber S3 has an axial second side A2 that communicates with the transmission mechanism housing chamber S2 (particularly the differential gear housing chamber S22). Furthermore, an object to be lubricated by oil is placed in the axial first side A1 of the output shaft housing chamber S3. That is, the end of the axial first side A1 of the output shaft housing chamber S3 communicates with the space S31 in which the object to be lubricated by oil is placed. In this embodiment, the object to be lubricated by oil includes a bearing BR2 and an oil seal 700. The oil seal 700 is provided at the end of the axial first side A1 of the first output member 61 and provides an oil-tight seal between the first output member 61 and the case 2. In a modified example, instead of the output shaft housing chamber S3 communicating with the space S31 in which the bearing BR2 and oil seal 700 are placed, the end of the axial first side A1 may enclose the space S31 (the space in which the bearing BR2 and oil seal 700 are placed).

[0064] In this embodiment, oil is circulated within the vehicle drive unit 100 by a lubrication method (natural lubrication method) in which oil is stirred up by the rotation of gears, rather than by a so-called forced lubrication method using an oil pump (mechanical or electric oil pump). However, in modified cases, an oil pump may be used in combination for some of the lubrication.

[0065] Specifically, in this embodiment, a lubrication method is employed in which various objects to be lubricated are lubricated by scraping them up with the rotation of the output gear 30 (so-called differential ring) of the differential gear mechanism 5.

[0066] In this way, according to this embodiment, by adopting such a natural lubrication method in the vehicle drive unit 100, it is possible to reduce costs and size by eliminating the oil pump.

[0067] On the other hand, with natural lubrication, properly supplying oil to the aforementioned bearing BR2 and oil seal 700 often necessitates raising the oil level or installing additional components such as catch tanks. Raising the oil level increases the required oil volume, leading to increased costs.

[0068] Therefore, in this embodiment, the surface 231 of the output shaft case portion 23 facing the first output member 61 (hereinafter also referred to as the "inner peripheral wall surface 231") (see Figure 5), and the outer peripheral surface of the first output member 61 are configured such that the axial first side A1 extends to a position lower than the axial second side A2.

[0069] Specifically, the inner surface 231 of the peripheral wall includes an inclined surface that forms a height difference between the first axial side A1 and the second axial side A2. Such an inclined surface may be realized by increasing the inner diameter (inner diameter around the first axis C1) of the inner surface 231 of the peripheral wall as it approaches the first axial side A1. However, in other embodiments, a step may be formed instead of or in addition to the inclined surface. In this case as well, the step may be formed such that the inner diameter (inner diameter around the first axis C1) of the inner surface 231 of the peripheral wall increases in stages as it approaches the first axial side A1.

[0070] Similarly, the outer circumferential surface of the first output member 61 also includes an inclined surface that forms a height difference between the axial first side A1 and the axial second side A2. Such an inclined surface may be realized by increasing the outer diameter of the outer circumferential surface of the first output member 61 (outer diameter around the first axis C1) as it approaches the axial first side A1. In this case, the outer diameter of the outer circumferential surface of the first output member 61 may be a constant value smaller than the inner diameter of the inner circumferential surface 231 of the peripheral wall at each position along the axial direction. However, in other embodiments, steps may be formed instead of or in addition to the inclined surface.

[0071] The inner circumferential surface 231 of the peripheral wall and the outer circumferential surface of the first output member 61 can utilize the action of gravity to allow oil supplied from the axial second side A2 by the rotation of the output gear 30 of the differential gear mechanism 5 to flow along the inclined surface to the axial first side A1 at a relatively large flow rate. Specifically, the oil supplied from the axial second side A2 by the rotation of the output gear 30 of the differential gear mechanism 5 (see arrow R61 in Figure 5) falls onto the surface of the first output member 61 and then flows along the surface of the first output member 61 to the axial first side A1 (see arrow R62 in Figure 5). At this time, the flow of oil to the axial first side A1 is promoted due to the inclination of the surface of the first output member 61. In addition, the oil supplied from the axial second side A2 by the rotation of the output gear 30 of the differential gear mechanism 5 (see arrow R61 in Figure 5) falls either via the surface of the first output member 61 or directly onto the upward-facing surface portion of the inner circumferential surface 231 of the peripheral wall. Subsequently, the oil flows along the upward-facing surface portion of the inner circumferential wall surface 231 toward the first axial side A1 (see arrow R63 in Figure 5). At this time, the inclination of the inner circumferential wall surface 231 promotes the flow of oil toward the first axial side A1. As a result, oil can be supplied at an appropriate flow rate to the lubrication target (bearing BR2 or oil seal 700) located at or near the end of the first axial side A1 of the first output member 61.

[0072] In this embodiment, without providing additional parts such as a catch tank, the oil scooped up by the rotation of the output gear 30 of the differential gear mechanism 5 can be appropriately supplied to the lubricated objects (bearing BR2 and oil seal 700). Therefore, while achieving miniaturization and cost reduction through a natural lubrication method, oil can be appropriately supplied to lubricated objects (bearing BR2 and oil seal 700) located relatively far in the axial direction from the output gear 30 of the differential gear mechanism 5.

[0073] In this embodiment, the portion of the transmission mechanism case 22 located at the boundary with the output shaft case 23 in the axial direction (hereinafter also referred to as the "bearing support portion 223") has a cavity S223 (see Figure 5). The bearing support portion 223 is located around the bearing BR1 and is the part that supports the bearing BR1. In this case, the cavity S223 is located radially outward of the bearing BR1 and may be formed at a height over which oil scraped up by the rotation of the output gear 30 of the differential gear mechanism 5 is applied. Two or more cavities S223 may be provided around the bearing BR1, for example, directly above it in the vertical direction (12 o'clock position) and below it (for example, at the 11 o'clock position).

[0074] By providing such a cavity S223, the oil sloshed up by the rotation of the output gear 30 of the differential gear mechanism 5 can be introduced into the output shaft housing chamber S3 from the axial second side A2 at an appropriate flow rate. Furthermore, the oil sloshed up by the rotation of the output gear 30 of the differential gear mechanism 5 can be directly introduced into the cavity S223. Therefore, it can be introduced into the output shaft housing chamber S3 from the axial second side A2 at an appropriate flow rate without the need for additional parts such as a catch tank.

[0075] In this embodiment, as shown in Figures 2 and 5, the oil supplied to the motor housing chamber S1 and the output shaft housing chamber S3 for lubrication is returned to the transmission mechanism housing chamber S2 (particularly the differential gear housing chamber S22) via a return passage 290 formed in the lower part of the case 2.

[0076] The return passage 290 has an end on the axial second side A2 that opens into the differential gear housing chamber S22, and an end on the axial first side A1 that communicates with the output shaft housing chamber S3. The output shaft case portion 23 may have an opening or notch 99 (see Figure 3A) to ensure communication between the output shaft housing chamber S3 and the return passage 290. This allows oil to be efficiently introduced from inside the output shaft housing chamber S3 into the return passage 290.

[0077] Next, referring primarily to Figure 6, we will mainly explain the structure within the transmission mechanism housing chamber S2 of the oil passage structure.

[0078] In this embodiment, as described above, a natural lubrication method is employed, so it is useful to return the oil used to lubricate various lubricated objects to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly. For example, if a return passage such as the return passage 290 described above opens to the reduction mechanism housing chamber S21, which is part of the transmission mechanism housing chamber S2 other than the differential gear housing chamber S22, there is a tendency for insufficient oil to return to the lower part of the differential gear housing chamber S22 via the return passage. In this case, depending on the vehicle's driving conditions, the oil temperature sensor may not be immersed in oil and may measure the internal air temperature instead. To eliminate such inconveniences, it is possible to increase the total amount of oil, but in this case, problems such as increased costs due to the increased amount of oil and increased agitation losses due to the rise in the oil level in a static state (agitation losses by the output gear 30) may arise.

[0079] Therefore, in this embodiment, the return passage 290 opens at the lower part of the differential gear housing chamber S22 (below the second shaft C2) within the transmission mechanism housing chamber S2. In this case, the axial second side A2 end of the return passage 290 (the opening on the differential gear housing chamber S22 side) preferably overlaps the output gear 30 when viewed in the axial direction. This makes it possible to return the oil used to lubricate various lubricated objects, including the bearing BR2 and oil seal 700 mentioned above, to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly.

[0080] In this embodiment, as described above, a flow path forming member 90 is provided on the radially outer side of the rotating electric machine 1. The radially inner side of the flow path forming member 90 is fitted to the stator core 12, and the radially outer side is sealed on both sides in the axial direction to the flow path forming surface 209 of the case 2. That is, the flow path forming member 90 is provided in such a manner that it separates the movement of oil between the space S11 (see Figure 2) where the coil end 13 on the axial second side A2 (in this embodiment, the lead-side coil end 13-1) is located in the motor housing chamber S1, and the space S12 (see Figure 2) where the coil end 13 on the axial first side A1 is located. For this reason, the space S11 (see Figure 2) where the coil end 13 on the axial second side A2 (in this embodiment, the lead-side coil end 13-1) is located in the motor housing chamber S1, and the space S12 (see Figure 2) where the coil end 13-2 on the axial first side A1 is located, are not substantially in communication in the axial direction. In other words, a refrigerant flow path 300 is formed over the entire circumferential area of ​​the rotating electric machine 1, and there is no gap between the rotating electric machine 1 and the flow path forming member 90 in the radial direction. Therefore, no movement of oil through this gap (movement between space S11 and space S12) occurs. Consequently, the oil ejected towards each coil end 13 via the axial oil passage 15a of the rotor shaft 15 and the radial ejection holes 15b of the rotor shaft 15 (oil ejected by centrifugal force during rotor rotation) cannot be returned to the transmission mechanism housing chamber S2 by a single return flow path. Specifically, the oil injected into the coil end 13 in space S12 can be returned to the transmission mechanism housing chamber S2 (especially the differential gear housing chamber S22) by the return flow path 290 described above, due to the communication between space S12 and the output shaft housing chamber S3 (see Figure 2). On the other hand, the oil injected into the coil end 13 in space S11 cannot be returned to the transmission mechanism housing chamber S2 (especially the differential gear housing chamber S22) by the return flow path 290 described above.

[0081] Therefore, in this embodiment, a second return passage 292 is provided, which connects the space S11 and the transmission mechanism housing chamber S2. Specifically, the end of the return passage 292 on the axial first side A1 communicates with the space S11 of the motor housing chamber S1, and the end of the axial second side A2 communicates with the lower part of the transmission mechanism housing chamber S2 (the lower part of the catch tank 920, which will be described later). In this embodiment, the end of the return passage 292 on the axial second side A2 opens to the lower part of the reduction mechanism housing chamber S21 (below the first axis C1). In this case, the end of the return passage 292 on the axial second side A2 (the opening on the reduction mechanism housing chamber S21 side) preferably opens below the second axis C2. This makes it possible to return the oil used to cool the coil end 13 in the aforementioned space S11 to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) via the reduction mechanism housing chamber S21. In other words, while realizing a water-cooling structure around the stator core 12 using the flow path forming member 90, the oil supplied to the motor housing chamber S1 can be efficiently returned to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed).

[0082] In this embodiment, the axial second side A2 of the return passage 292 (the opening on the reduction mechanism housing chamber S21 side) is located inside the catch tank 920 within the reduction mechanism housing chamber S21. As shown in Figure 6, the return passage 292 may be in the form of a hole that penetrates axially through the partition wall that axially separates the motor housing chamber S1 and the transmission mechanism housing chamber S2 in the case 2.

[0083] As shown in Figure 6, the catch tank 920 extends radially outward from the axial wall portion 9201 around the reduction mechanism 34 in the reduction mechanism housing chamber S21 and has an inlet 921 at a position capable of capturing oil scraped up by the rotation of the output gear 30. The catch tank 920 also has an outlet 922 at its lower part that opens into the differential gear housing chamber S22. In this case, the end of the axial second side A2 of the return passage 292 (the opening on the reduction mechanism housing chamber S21 side) may be provided near the outlet 922. This makes it possible to return the oil used to cool the coil end 13 in the space S11 to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly via the lower part of the catch tank 920. The catch tank 920 may also be connected to the axial oil passage 15a of the rotor shaft 15, etc., to supply oil to the axial oil passage 15a of the rotor shaft 15. Furthermore, the lower part of the catch tank 920 refers to the portion below the vertical center of the catch tank 920, for example, the portion below the first shaft C1.

[0084] In the modified configuration, the return channel 292 may be connected to the return channel 290 described above. For example, the return channel 292 may be formed as a channel connecting space S11 and the return channel 290. In this case, the overall length of the return channel can be reduced, and an efficient return channel configuration can be achieved.

[0085] An oil temperature sensor 98 (schematically shown as a circle in Figure 6) is provided at the bottom of the catch tank 920. In this case, the oil temperature sensor 98 is located near the outlet 922 of the catch tank 920. This reduces the possibility that the oil temperature sensor 98 may rise above the oil level depending on the vehicle's driving conditions, thereby improving the reliability of the sensor information from the oil temperature sensor 98.

[0086] In this embodiment, as described above, the oil scraped up by the rotation of the output gear 30 of the differential gear mechanism 5 is introduced from the transmission mechanism housing chamber S2 to the output shaft housing chamber S3 via the cavity S223 located above the second shaft C2. The oil then flows downward due to gravity, lubricating the bearing BR2 and the like, and is returned from the output shaft housing chamber S3 to the differential gear housing chamber S22 via the end of the return passage 290 located below the second shaft C2 (the end of the axial second side A2). This makes it possible to scrape the oil again by the rotation of the output gear 30 of the differential gear mechanism 5.

[0087] Furthermore, the oil stirred up by the rotation of the output gear 30 of the differential gear mechanism 5 is introduced into the axial oil passage 15a of the rotor shaft 15 via the catch tank 920. Specifically, the catch tank 920 is provided with a communication port 75 at its top. The communication port 75 is the radially outer opening of the radial communication passage 74, and the radially inner end of the communication passage 74 is connected to the axial oil passage 16a of the input member 16. In this case, the oil stirred up by the rotation of the output gear 30 of the differential gear mechanism 5 enters the communication passage 74 from the communication port 75 of the catch tank 920, and is then supplied to the axial oil passage 15a of the rotor shaft 15 via the axial oil passage 16a. The oil supplied to the axial oil passage 15a is ejected from the ejection hole 15b to the coil end 13 of the rotating electric machine 1, as described above. This allows the coil end 13 to be efficiently cooled by the oil churned up by the rotation of the output gear 30 of the differential gear mechanism 5. The oil sprayed onto the coil end 13 in space S12 of the motor housing chamber S1 is returned from space S12 to the transmission mechanism housing chamber S2 via the end of the return passage 290 located below the second shaft C2 (the end of the axial second side A2). Similarly, the oil sprayed onto the coil end 13 in space S11 of the motor housing chamber S1 is returned from space S11 to the transmission mechanism housing chamber S2 via the end of the return passage 292 located below the second shaft C2 (the end of the axial second side A2). The oil returned to the transmission mechanism housing chamber S2 in this way is returned to the differential gear housing chamber S22 from the outlet 922 in the catch tank 920 located below the second shaft C2. This makes it possible to churn it up again by the rotation of the output gear 30 of the differential gear mechanism 5.

[0088] Next, with reference to Figures 3 and 7, the preferred arrangement of the breather 150 in this embodiment will be described in detail.

[0089] Figure 7 is a schematic cross-sectional view of the vehicle drive unit 100 through a vertical plane passing through the breather 150.

[0090] The breather 150 has the function of opening the motor housing chamber S1 and the transmission mechanism housing chamber S2, which are formed by the case 2 of the vehicle drive unit 100, to atmospheric pressure. The breather 150 is installed at the top of the case 2 to prevent oil (for example, oil that accumulates at the bottom) from entering the case 2 when the vehicle's behavior changes.

[0091] Specifically, as shown in Figure 7, the breather 150 includes a first passage 151 extending in the axial direction A and a second passage 152 extending in the vertical direction, which mainly form the breather chamber. The first passage 151 has openings at both ends and forms a first opening 153 that opens into the motor housing chamber S1 and a second opening 154 that opens into the transmission mechanism housing chamber S2. The second passage 152 has its lower end connected to (opening into) the first passage 151 and forms a third opening 156 that opens to the atmosphere at its upper end. A breather valve 158 may be attached to the third opening 156. The detailed configuration of the breather valve 158 is arbitrary, but it may have a configuration such as that disclosed in Japanese Patent Application Publication No. 2007-127139, whose contents may be incorporated into this application by reference herein.

[0092] With this configuration, the breather 150 can open the motor housing chamber S1 to atmospheric pressure through the first opening 153 and the third opening 156 that open into the motor housing chamber S1. In addition, the breather 150 can open the transmission mechanism housing chamber S2 to atmospheric pressure through the second opening 154 and the third opening 156 that open into the transmission mechanism housing chamber S2. Therefore, a more efficient configuration can be achieved compared to a configuration in which a breather for the motor housing chamber S1 and a breather for the transmission mechanism housing chamber S2 are provided separately.

[0093] In this embodiment, the third opening 156 is positioned near the center of the case 2 when viewed in the vertical direction, as can be seen from the position of the breather valve 158 shown in Figure 3. Specifically, the third opening 156 is positioned between the first axis C1 and the second axis C2 in the first direction X (an example of a direction perpendicular to the first axis), and between the center position of the rotating electric machine 1 and the center position of the reduction mechanism 34 in the axial direction A (an example of a direction parallel to the first axis). The center position of the rotating electric machine 1 in the axial direction A may correspond to, for example, the axial center position of the stator core 12. The center position of the reduction mechanism 34 in the axial direction A may correspond to an intermediate position between the position A1 on the axial first side and the position A2 on the axial second side of the reduction mechanism 34.

[0094] With this arrangement of the breather 150, the breather 150 can be easily implemented by utilizing the dead space that is easily formed between the rotating electric machine 1 and the reduction mechanism 34 in the axial direction A, and between the first axis C1 and the second axis C2.

[0095] In particular, the third opening 156 is preferably positioned on the axial second side A2 (i.e., closer to the reduction mechanism 34) than the coil end 13-1 on the axial second side A2. This is because a dead space, as shown by Q1 in Figure 2, is more likely to form on the axial second side A2 than the coil end 13-1 on the axial second side A2. The area shown by Q1 in Figure 2 is part of this dead space and is located between bearing BR3 and bearing BR1 in the first direction X.

[0096] Incidentally, in this embodiment, as described above, the inverter housing chamber S4 (inverter case section 24) forms the upper part of the case 2 and extends over a relatively wide area.

[0097] Therefore, in this embodiment, the third opening 156 is positioned at a distance from the inverter housing chamber S4 (inverter case portion 24) when viewed in the vertical direction, as can be seen from the position of the breather valve 158 shown in Figure 3. In particular, in this embodiment, it is positioned near the L-shaped corner of the inverter housing chamber S4. This allows the inverter housing chamber S4 described above to be established while positioning the third opening 156 of the breather 150 near the center of the case 2 when viewed in the vertical direction. In other words, according to this embodiment, by forming the inverter housing chamber S4 in an L-shape, the vertical size of the vehicle drive unit 100 can be reduced while positioning the third opening 156 of the breather 150 near the center of the case 2 when viewed in the vertical direction.

[0098] Next, referring to Figure 8 and subsequent figures, we will describe another embodiment (hereinafter also referred to as "Embodiment 2" for distinction purposes) that differs from the embodiment described above (hereinafter also referred to as "Embodiment 1" for distinction purposes). In the following, we will mainly describe the configuration of Embodiment 2 as differing from that of Embodiment 1 described above, but other configurations not described for Embodiment 2 may be the same as those of Embodiment 1 described above.

[0099] Figure 8 is a schematic cross-sectional view of the vehicle drive unit 100A in a vertical plane passing through the breather 150A according to this embodiment 2. Figure 9 is a schematic side view showing the bulkhead 26 in the vehicle drive unit 100A according to this embodiment 2, viewed from the axial first side A1. In Figure 9, for ease of viewing, some of the components inside the motor housing chamber S1 (such as the rotating electric machine 1) are omitted. Also, in Figure 9, for ease of viewing, some of the insulating member 160 (lid portion 169), which will be described later, is not shown.

[0100] The vehicle drive unit 100A according to this embodiment 2 differs from the vehicle drive unit 100 according to embodiment 1 described above mainly in that the breather 150 is replaced with a breather 150A.

[0101] The breather 150A differs from the breather 150 in the configuration of the motor housing chamber S1 described above.

[0102] Specifically, the breather 150A has an opening 155A on the motor housing chamber S1 side formed by the case 2A, instead of the first opening 153 of the breather 150 according to the above-described embodiment 1. Unlike the breather 150 according to the above-described embodiment 1, the breather 150A opens to the motor housing chamber S1 via an insulating member 160, which is a separate component from the case 2A described later.

[0103] The insulating member 160 is formed of an insulating material (e.g., a resin material) that has electrical insulating properties, and forms the insulating portion of the breather 150A. That is, the breather 150A includes an insulating portion formed by the insulating member 160 in addition to the conductive portion formed by the case 2A.

[0104] In this embodiment 2, the insulating member 160, together with the case 2A, forms the breather chamber of the breather 150A. Specifically, the breather chamber of the breather 150A includes a space (an example of a first breather chamber) formed by the first passage 151 and the second passage 152 formed by the case 2A, as well as a space (an example of a second breather chamber) formed by the insulating member 160.

[0105] Figures 10 to 12 are explanatory diagrams of the insulating member 160. Figure 10 is an enlarged view of part Q10 in Figure 8. Figure 11 is a perspective view of the insulating member 160 in its individual state, viewed from the first axial side A1. Figure 12 is an exploded perspective view of the insulating member 160 from the same view as Figure 11. Figure 13 is a perspective view of the insulating member 160 in its individual state, viewed from the second axial side A2.

[0106] The insulating member 160 is attached to the partition wall 26 of the case 2A in a manner that it is located in the motor housing chamber S1. The method of attaching the insulating member 160 is arbitrary, but it may be fastened to the partition wall 26 by means of bolt holes BT5 (see Figure 11), for example.

[0107] The insulating member 160 includes a main body portion 161 and a lid portion 169.

[0108] The main body portion 161 forms a common passage 162 that overlaps the first passage 151 when viewed in the axial direction A. The axial dimension of the common passage 162 may be relatively small. The main body portion 161 has an outer peripheral wall portion 1620 that borders the common passage 162 when viewed in the axial direction. The outer peripheral wall portion 1620 is formed in such a manner that it protrudes from the outer peripheral edge of the main wall portion 1610 of the main body portion 161 toward the first axial side A1. The main wall portion 1610 of the main body portion 161 extends in a plane substantially perpendicular to the axial direction A.

[0109] The main body portion 161 forms a common passage 162 in a manner that communicates with the first passage 151. Specifically, the main wall portion 1610 of the main body portion 161 has a through hole 1613 in the axial direction A, and the common passage 162 communicates with the first passage 151 via the through hole 1613. In this embodiment 2, the through hole 1613 is formed on the inner circumference side of the cylindrical fitting portion 165. The cylindrical fitting portion 165 is formed on the axial first side A1 of the main wall portion 1610 of the main body portion 161. In this case, the insulating member 160 is fitted into the case 2A in a manner that the cylindrical fitting portion 165 is inserted into the first passage 151 through the opening 155A.

[0110] The main body 161 is further formed into two passages that communicate with the common passage 162: a ventilation passage 163 and a drain passage 164. The main body 161 has a hollow projection 1630 for ventilation that borders the ventilation passage 163 and a hollow projection 1640 for drainage that borders the drain passage 164.

[0111] The hollow projection 1630 for ventilation is cylindrical in shape and protrudes from the main wall 1610 of the main body 161 toward the second axial side A2. The hollow projection 1630 for ventilation may protrude toward the second axial side A2 in such a manner that it reaches the vicinity of the partition wall 26 in the axial direction A. The hollow projection 1630 for ventilation extends in the axial direction A, connects to the main wall 1610 on the first axial side A1, and opens toward the second axial side A2. Therefore, the ventilation passage 163 formed by the hollow projection 1630 for ventilation communicates with the common passage 162 on the first axial side A1 and communicates with (opens toward) the motor housing chamber S1 on the second axial side A2. The opening on the second axial side A2 of the hollow projection 1630 for ventilation forms a ventilation hole 1631. The hollow ventilation projection 1630 is preferably located at a relatively high position. For example, the hollow ventilation projection 1630 is located above the through hole 1613 and is located at the highest point of the common passage 162 when viewed in the axial direction A (see ventilation hole 1631 in Figure 9). This effectively reduces the possibility of oil entering the ventilation passage 163.

[0112] The hollow projection 1640 for drainage is cylindrical in shape and protrudes from the main wall 1610 of the main body 161 toward the second axial side A2. The hollow projection 1640 for drainage may protrude toward the second axial side A2 in such a manner that it reaches the vicinity of the partition wall 26 in the axial direction A. The hollow projection 1640 for drainage extends in the axial direction A, connects to the main wall 1610 on the first axial side A1, and opens toward the second axial side A2. Therefore, the drain passage 164 formed by the hollow projection 1640 for drainage communicates with the common passage 162 on the first axial side A1 and communicates with (opens toward) the motor housing chamber S1 on the second axial side A2. The opening on the second axial side A2 of the hollow projection 1640 for drainage forms a drain hole 1641. The hollow projection 1640 for drainage is provided at a relatively low position. For example, the hollow projection 1640 for drainage is located below the through-hole 1613 and is positioned at the lowest point of the common passage 162 when viewed in the axial direction A (see drain hole 1641 in Figure 9). This ensures that oil that has entered the breather 150A is returned without any loss to the motor housing chamber S1 via the drain passage 164.

[0113] The cover portion 169 is provided to cover the axial first side A1 of the common passage 162. Accordingly, the cover portion 169 is coupled to the main body portion 161 in such a manner that it abuts against the end face of the axial first side A1 of the outer peripheral wall portion 1620. The method of coupling the cover portion 169 to the main body portion 161 is arbitrary and may be achieved by fitting, adhesive, etc. Also, a sealing member (not shown) may be provided between the main body portion 161 and the cover portion 169, but preferably the sealing member is omitted to reduce the number of parts.

[0114] In this way, the insulating member 160, having a main body portion 161 and a lid portion 169, can form a new breather chamber (a breather chamber different from the space formed by case 2A) through a common passage 162, a ventilation passage 163, and a drain passage 164. This makes it easy to secure the necessary volume for the breather chamber of the breather 150A as a whole.

[0115] Furthermore, since the insulating member 160 forms a ventilation passage 163 with a hollow projection 1630 for ventilation, the volume of the ventilation passage 163 can be made relatively large by the axial length of the hollow projection 1630 for ventilation. The same applies to the drain passage 164. Therefore, it becomes even easier to secure the required volume of the breather chamber as a whole for the breather 150A. In addition, since the insulating member 160 can be formed from a resin material or the like, the space formed by the insulating member 160 has a higher degree of freedom in shape than the space formed by the case 2A. Therefore, the hollow projection 1630 for ventilation and the hollow projection 1640 for drain can be formed with a relatively high degree of freedom in shape.

[0116] Incidentally, in the motor housing chamber S1, oil (for example, oil sprayed through the ejection holes 15b) is scattered due to the rotation of the rotor 14 of the rotating electric machine 1. Therefore, the breather 150A, which is located near the rotating electric machine 1, is prone to getting covered in oil, and consequently, oil is likely to enter the breather chamber.

[0117] In this regard, in this embodiment 2, the hollow projection 1630 for ventilation and the hollow projection 1640 for drainage are located in the second axial direction A2 relative to the main wall 1610, as described above. For example, the hollow projection 1630 for ventilation and the hollow projection 1640 for drainage are located in the second axial direction A2 relative to the axial position A1, which is the axial position furthest axially on the first side of the first passage 151. This effectively reduces the possibility of oil entering the breather chamber through the ventilation holes 1631 and the drain holes 1641. In particular, if the hollow projection 1630 for ventilation and the hollow projection 1640 for drainage extend in the axial direction A to the vicinity of the partition wall 26, the possibility of oil entering the breather chamber through the ventilation holes 1631 and the drain holes 1641 can be significantly reduced.

[0118] Furthermore, in this embodiment 2, the breather 150A can be positioned between the partition wall 26 and the rotating electric machine 1 in the axial direction, avoiding the rotation angle sensor 88. That is, the breather 150A can be positioned by efficiently utilizing the dead space between the partition wall 26 and the rotating electric machine 1 in the axial direction. Specifically, as shown in Figure 8, the hollow projection 1630 for ventilation and the hollow projection 1640 for drainage extend axially to the second axial side A2 beyond the rotation angle sensor 88. That is, the axial positioning range of both the ventilation passage 163 and the drainage passage 164 overlaps with that of the rotation angle sensor 88. As a result, the volume of the breather chamber of the breather 150A can be efficiently increased while positioning the breather 150A together with the rotation angle sensor 88 between the partition wall 26 and the rotating electric machine 1 in the axial direction. Note that in this embodiment 2, the rotation angle sensor 88 is, for example, in the form of a resolver, but it may be in other forms as well.

[0119] Next, we will explain the further advantages of this embodiment 2 in comparison with the comparative example shown in Figure 14.

[0120] Figure 14 is a schematic cross-sectional view of a vehicle drive unit 100A through a vertical plane passing through a breather 150' according to a comparative example.

[0121] The breather 150' in the comparative example differs from the breather 150A in this embodiment 2 in that the insulating member 160 is replaced with a metallic lid member 28'.

[0122] The lid member 28' is formed from the same material as case 2A (e.g., aluminum). The lid member 28' is in the form of a flat plate and covers the opening 155A on the axial first side A1 of the first passage 151. The lid member 28' may have drain holes 1641' and ventilation holes 1631'.

[0123] In the comparative example and this embodiment 2, the first passage 151 faces the coil end 13-1 when viewed in the axial direction A. Therefore, if the first passage 151 is extended axially towards the first side A1, the electrical insulation distance between the coil end 13-1 and the end of the axial first side A1 in case 2A (specifically, the outer peripheral edge around the first passage 151) becomes shorter. Consequently, due to the need (constraint) to secure the necessary electrical insulation distance between the coil end 13-1 and the end of the axial first side A1 in case 2A, it is difficult to increase the volume of the breather chamber by extending the first passage 151 axially towards the first side A1.

[0124] In the comparative example, the lid member 28' is a conductor facing the coil end 13-1 in the axial direction, and is therefore positioned at a distance of at least the required electrical insulation distance L14 (see Figure 14) from the coil end 13-1.

[0125] In contrast, according to this embodiment 2, the insulating member 160 described above is provided so as to cover the portion 29 (part of the partition wall 26) around the first passage 151 in case 2A. As a result, the insulating member 160 is positioned between the portion 29 around the first passage 151 in case 2A and the coil end 13-1. Consequently, the electrical insulation between the coil end 13-1 and the axial first side A1 end (portion 29 around the first passage 151) in case 2A can be improved. In other words, the insulating member 160 described above can face the coil end 13-1 in the axial direction while being close to the coil end 13-1. By bringing the insulating member 160 closer to the coil end 13-1 (for example, to a distance smaller than the insulation distance L14), the volume of the breather chamber formed by the insulating member 160 (for example, the volume of the common passage 162) can be increased. In this way, according to this embodiment 2, even when the breather 150A is positioned opposite the coil end 13-1 in the axial direction, the necessary insulation distance from the coil end 13-1 can be secured while ensuring the necessary volume of the breather chamber of the breather 150A.

[0126] In this embodiment 2, a second opening 154 similar to that in embodiment 1 described above is provided, but the second opening 154 may be omitted. That is, the breather 150A may be configured not to open into the transmission mechanism housing chamber S2.

[0127] Furthermore, in this embodiment 2, a third opening 156 similar to that in embodiment 1 described above is provided, but the opening corresponding to the third opening 156 (an atmospheric opening that opens to the atmosphere) may be provided at a different position than in embodiment 1 described above.

[0128] Furthermore, in this embodiment 2, a preferred configuration includes a hollow projection 1630 for ventilation and a hollow projection 1640 for draining, but either one or both may be omitted. For example, if the hollow projection 1630 for ventilation is omitted, a ventilation hole may be provided on the upper side of the lid 169.

[0129] Furthermore, in this embodiment 2, the ventilation hole 1631 of the breather 150A opens into the motor housing chamber S1, but the ventilation hole 1631 may also be provided in a manner that opens into the transmission mechanism housing chamber S2. In this case, the hollow projection 1630 for ventilation may be omitted, or a similar hollow projection for ventilation may be provided, differing only in that it does not have a ventilation hole 1631. Even in the latter case, the required volume of the breather chamber of the breather 150A can still be efficiently secured.

[0130] Furthermore, in this embodiment 2, the drain hole 1641 of the breather 150A opens into the motor housing chamber S1, but the drain hole 1641 may also be provided in a manner that opens into the transmission mechanism housing chamber S2. In this case, the hollow projection 1640 for draining may be omitted, or a similar hollow projection for draining may be provided, differing only in that it does not have a drain hole 1641. Even in the latter case, the required volume of the breather chamber of the breather 150A can still be efficiently secured.

[0131] Furthermore, in this embodiment 2, a rotating electric machine 1 and a transmission mechanism 3 are provided, but either one may be omitted. For example, if the rotating electric machine 1 is omitted (for example, if an engine is provided), an insulating member corresponding to the insulating member 160 may be provided on the second opening 154 side.

[0132] 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.

[0133] Furthermore, the following is disclosed regarding the above embodiments.

[0134] In conventional technologies as described above, when oil circulates to other chambers besides the motor chamber (for example, the chamber housing the transmission mechanism), a separate space is required specifically for the breather chamber, making it difficult to reduce the overall size of the vehicle's drive system.

[0135] Therefore, in one respect, the invention described below aims to eliminate or reduce the increase in the size of the vehicle drive system caused by the breather.

[0136] (Note 1) A rotating electric machine with the first shaft as its axis, A transmission mechanism for transmitting the driving force from the rotating electric machine to the wheels, comprising: a first transmission mechanism section arranged with the first shaft as its axis; and a second transmission mechanism section arranged with a second shaft parallel to the first shaft as its axis; A case housing the aforementioned rotating electric machine and the aforementioned transmission mechanism, The case is provided with a breather, Within the case, oil can flow back and forth between the first housing chamber housing the rotating electric machine and the second housing chamber housing the transmission mechanism. The breather has a first opening that opens into the first containment chamber, a second opening that opens into the second containment chamber, and a third opening that opens to the atmosphere. The third opening is positioned, when viewed in the vertical direction, between the first and second axes in a direction perpendicular to the first axis, and between the center position of the rotating electric machine and the center position of the first transmission mechanism in a direction parallel to the first axis, in a vehicle drive device.

[0137] (Note 2) The rotating electric machine has a first coil end on the side closer to the first transmission mechanism in the axial direction, and a second coil end on the side further away from the first transmission mechanism in the axial direction. The vehicle drive device as described in Appendix 1, wherein the third opening is, when viewed in the vertical direction, closer to the first transmission mechanism in the axial direction than the first coil end.

[0138] (Note 3) A first output member is one of a pair of output members that are driven and connected between a pair of wheels and the transmission mechanism, A first bearing rotatably supports the rotor shaft of the rotating electric machine on the side closer to the first transmission mechanism in the axial direction, The system further includes a second bearing that rotatably supports the first output member on the side closer to the second transmission mechanism in the axial direction, The vehicle drive device according to Appendix 1, wherein the third opening is positioned between the first bearing and the second bearing in a direction perpendicular to the first axis when viewed in the vertical direction.

[0139] (Note 4) The system further includes an inverter device that receives power from a battery and supplies power to the rotating electric machine, The aforementioned case further houses the inverter device, The vehicle drive device according to any one of the appendices 1 to 3, wherein the third opening is located at a distance from the third housing chamber in the case that houses the inverter device when viewed in the vertical direction.

[0140] (Note 5) An inverter device that receives power from a battery and supplies power to the rotating electric machine, further comprising a power module and an inverter device having a wiring section that electrically connects the rotating electric machine and the power module, The aforementioned case further houses the inverter device, The third housing chamber in the case that houses the inverter device overlaps the first transmission mechanism, the second transmission mechanism, and the first output member when viewed in the vertical direction. The vehicle drive device according to Appendix 3, wherein the third opening is located at a distance from the third housing chamber when viewed in the vertical direction. [Explanation of symbols]

[0141] 100...Vehicle drive unit, 1...Rotating electric machine (drive source), 2...Case, 3...Transmission mechanism, 13-1...Coil end (coil end), 150A...Breather, 151...First passage (breather chamber, first breather chamber), 152...Second passage (breather chamber, first breather chamber), 156...Third opening (atmospheric opening), 160...Insulating member, 162...Common passage (breather chamber, second breather chamber), 163...Ventilation passage (breather chamber, second breather chamber), 164...Drain passage (breather chamber, second breather chamber), 1631...Ventilation hole (opening on case side), 1641...Drain hole (opening on case side), 88...Rotation angle sensor

Claims

1. A transmission mechanism that transmits the driving force from the power source to the wheels, A case forming a housing chamber that houses at least one of the drive source and the transmission mechanism together with oil, The case is provided with a breather, The aforementioned breather is A case-side opening that opens into the aforementioned storage chamber, An atmospheric opening that opens to the atmosphere, It has a case-side opening and a breather chamber that communicates with the atmospheric opening, The aforementioned breather chamber is A first breather chamber formed in the case, Including the second breather chamber, The second breather chamber is formed by an insulating member attached to the case within the containment chamber, The aforementioned drive source includes a rotating electric machine, The aforementioned housing chamber houses the rotating electric machine, The insulating member is located closer to the rotating electric machine than the first breather chamber in the axial direction, and faces the rotating electric machine when viewed in the axial direction, in a vehicle drive device.

2. The vehicle drive device according to claim 1, wherein the insulating member further forms the case-side opening.

3. The vehicle drive device according to claim 1 or 2, wherein the case-side opening is located at an axial position further away from the rotating electric machine than the axial position closest to the rotating electric machine in the first breather chamber.

4. A transmission mechanism that transmits the driving force from the power source to the wheels, A case forming a housing chamber that houses at least one of the drive source and the transmission mechanism together with oil, The case is provided with a breather, The aforementioned breather is A case-side opening that opens into the aforementioned storage chamber, An atmospheric opening that opens to the atmosphere, It has a case-side opening and a breather chamber that communicates with the atmospheric opening, The aforementioned breather chamber is A first breather chamber formed in the case, Including the second breather chamber, The second breather chamber is formed by an insulating member attached to the case within the containment chamber, The aforementioned drive source includes a rotating electric machine, The system further includes a rotation angle sensor that generates sensor information relating to the rotation angle of the aforementioned rotating electric machine, The aforementioned housing chamber houses the rotating electric machine and the rotation angle sensor, A vehicle drive system in which the axial arrangement ranges of the second breather chamber and the rotation angle sensor overlap.

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