Drive unit

Abstract

[Problem] To reduce the amount of oil discharged to the outside of a drive unit.　[Solution] A drive unit has a housing having a first accommodation chamber for accommodating a power transmission mechanism, a second accommodation chamber for accommodating a motor, a third accommodation chamber for accommodating an inverter, and a fourth accommodation chamber adjacent to the third accommodation chamber with a partition wall therebetween. A breather passage is configured to include a first passage provided in the partition wall and a second passage provided in the fourth accommodation chamber.

Description

Drive unit

[0001] The present invention relates to a drive unit.

[0002] Patent Document 1 and Patent Document 2 disclose a breather structure.

[0003] Japanese Patent Laid-Open No. 8-65945 Japanese Patent Laid-Open No. 2016-19436

[0004] It is required to reduce the amount of oil discharged to the outside of the drive unit.

[0005] The drive unit according to an aspect of the present invention has a housing having a first housing chamber for accommodating a power transmission mechanism, a second housing chamber for accommodating a motor, a third housing chamber for accommodating an inverter, and a fourth housing chamber adjacent to the third housing chamber with a partition therebetween, and a breather passage is constituted by including a first passage provided in the partition and a second passage provided in the fourth housing chamber.

[0006] According to an aspect of the present invention, the amount of oil discharged to the outside of the drive unit can be reduced.

[0007] FIG. 1 is a diagram for explaining a drive unit. FIG. 2 is a diagram for explaining a drive unit. FIG. 3 is a diagram for explaining a drive unit. FIG. 4 is a diagram for explaining an inverter case. FIG. 5 is a diagram for explaining an inverter case. FIG. 6 is a diagram for explaining a breather chamber. FIG. 7 is a diagram for explaining a breather chamber. FIG. 8 is a diagram for explaining the air flow in an inverter case. FIG. 9 is a diagram for explaining the connection of a power supply line to an inverter. FIG. 10 is a diagram for explaining a drive unit according to Modification 1. FIG. 11 is a diagram for explaining a drive unit according to Modification 2. FIG. 12 is a diagram for explaining a drive unit according to Modification 2.

[0008] First, the definitions of terms used in this specification will be explained. "Drive unit" means a device that includes a motor that generates power, or a motor and a mechanism for transmitting power (e.g., gears, transmission mechanism, etc.). Therefore, the term "drive unit" is used as a broad concept that includes both motor units, which include only a motor, and power transmission devices, which have a power transmission mechanism in addition to a motor. "Drive unit" is also called a "motor unit," "power transmission device," or "unit." A motor unit is a drive unit that has at least a motor. A power transmission device is a device that has at least a power transmission mechanism, and the power transmission mechanism is, for example, a gear mechanism and / or a differential gear mechanism. A drive unit, which is a device that has a motor and a power transmission mechanism, belongs to both the concepts of a motor unit and a power transmission device.

[0009] A "housing" is a component that houses the motor, gears, and inverter. A housing consists of one or more cases.

[0010] A "motor" is a rotating electric machine that has both electric motor and / or generator functions.

[0011] When it is stated that element B (part, component, etc.) is connected to element A (component, component, etc.), that element B (component, component, etc.) is connected downstream of element A (component, component, etc.), or that element B (component, component, etc.) is connected upstream of element A (component, component, etc.), it means that element A and element B are connected in a way that allows for power transmission. The power input side is the upstream side, and the power output side is the downstream side. In addition, element A and element B may be connected via other elements (clutch, other gear mechanisms, etc.).

[0012] "Overlapping in a specified direction" means that multiple elements are aligned in a specified direction, and is synonymous with the description "overlapping in a specified direction." The "specified direction" can be, for example, the axial direction, radial direction, direction of gravity, or vehicle travel direction (vehicle forward direction, vehicle reverse direction). If multiple elements (parts, sections, etc.) are shown aligned in a specified direction in the drawing, it can be assumed that there is a description in the specification explaining that they overlap in a specified direction.

[0013] "Not overlapping in a given direction" and "offset in a given direction" mean that multiple elements are not aligned in a given direction, and are equivalent to stating "not overlapping in a given direction" and "offset in a given direction." "Given direction" can be, for example, axial direction, radial direction, direction of gravity, or vehicle travel direction (vehicle forward direction, vehicle reverse direction). If a drawing shows that multiple elements (parts, sections, etc.) are not aligned in a given direction, it can be assumed that the description in the specification includes a statement explaining that they do not overlap in a given direction.

[0014] The statement "In a predetermined viewing direction, element A (part, etc.) is located between element B (part, etc.) and element C (part, etc.)" means that when observed from a predetermined direction, element A can be observed to be located between element B and element C. The "predetermined direction" is, for example, the axial direction, the radial direction, the direction of gravity, the direction of vehicle travel (vehicle forward direction, vehicle reverse direction), etc. For example, if elements B, A, and C are arranged in this order along the axial direction, then in a radial viewing direction, element A can be said to be located between element B and element C. If the drawing shows that element A is located between element B and element C in a predetermined viewing direction, it can be assumed that there is a sentence in the specification explaining that element A is located between element B and element C in a predetermined viewing direction.

[0015] When two elements (parts, components, etc.) overlap in an axial view, the two elements are coaxial.

[0016] "Axial direction" refers to the axial direction of the rotation axis of the components that make up the drive unit. "Radial direction" refers to the direction perpendicular to the rotation axis of the components that make up the drive unit. Components include, for example, motors, gear mechanisms, differential gear mechanisms, etc.

[0017] The following describes this embodiment. In this embodiment, a drive unit 1 mounted on a vehicle will be used as an example. Figure 1 is a diagram illustrating the drive unit 1. Figure 2 is a diagram illustrating the drive unit 1. Figure 2 is an enlarged view of the main part of Figure 1. Figure 3 is a diagram illustrating the drive unit 1. Figure 3 is an enlarged view of the area around the differential mechanism 6 in Figure 1.

[0018] Here, "vertical direction" in the drawings refers to the vertical direction relative to the state in which the drive unit 1 is mounted on the vehicle. Therefore, when it is written as "upper side," it refers to the "upper side" in the vertical direction, and when it is written as "lower side," it refers to the "lower side" in the vertical direction. Also, "front-rear direction" refers to the front-rear direction of the vehicle relative to the state in which the drive unit 1 is mounted on the vehicle. Therefore, when it is written as "front side," it refers to the "front side" in the front-rear direction, and when it is written as "rear side," it refers to the "rear side" in the front-rear direction.

[0019] As shown in Figure 1, the drive unit 1 includes a motor 2, a power transmission mechanism 3 that transmits the output rotation of the motor 2 to drive shafts DA and DB, and an inverter 7 which is a power conversion device for the motor 2.

[0020] The power transmission mechanism 3 includes a first planetary gear 4, a second planetary gear 5, and a differential mechanism 6. The first planetary gear 4 is connected downstream of the motor 2. The second planetary gear 5 is connected downstream of the first planetary gear 4. The differential mechanism 6 is connected downstream of the second planetary gear 5. The drive shafts DA and DB are connected downstream of the differential mechanism 6.

[0021] In the drive unit 1, the output rotation of the motor 2 is shifted (for example, reduced) by the first planetary gear 4 and the second planetary gear 5 and input to the differential mechanism 6, after which it is output to the left and right drive wheels (not shown) of the vehicle via the drive shafts DA and DB.

[0022] The drive unit 1 has a housing HS that houses a motor 2, a power transmission mechanism 3, and an inverter 7. The housing HS includes a motor case 10 that houses the motor 2, a gear case 14 that houses the power transmission mechanism 3, and an inverter case 8 that houses the inverter 7. Based on the installation state of the drive unit 1 on the vehicle, the gear case 14 is provided adjacent to the motor case 10 in the direction of the motor 2's rotation axis X. The inverter case 8 is provided adjacent to the upper parts of the motor case 10 and the gear case 14 in the vertical direction.

[0023] The motor case 10 includes a case member 11 and a cover member 12 joined to the case member 11. The case member 11 and the cover member 12 are joined to each other in the direction of the rotation axis X.

[0024] The case member 11 has a support wall portion 111 surrounding the rotation axis X. The support wall portion 111 is provided in a direction along the rotation axis X. The motor 2 is housed inside the support wall portion 111. A cover member 12 is connected to one end 111a of the support wall portion 111 in the direction of the rotation axis X by bolts (not shown). A gear case 14 is connected to the other end 111b of the support wall portion 111 by bolts (not shown).

[0025] The cover member 12 has a wall portion 120 perpendicular to the rotation axis X and a peripheral wall portion 121 surrounding the outer circumference of the wall portion 120. The peripheral wall portion 121 is joined to one end 111a of the support wall portion 111 of the case member 11 from the direction of the rotation axis X. In this state, the opening on the one end 111a side of the case member 11 is closed by the cover member 12.

[0026] In the wall portion 120, a cylindrical motor support portion 125 is provided in the region where the rotation axis X intersects. One end 20a of the motor shaft 20 of the motor 2 passes through the motor support portion 125 in the direction of the rotation axis X. A bearing B1 is supported on the inner circumference of the motor support portion 125. The outer circumference of the motor shaft 20 is supported by the motor support portion 125 via the bearing B1. An oil hole Ha is also formed in the motor support portion 125. The oil hole Ha is connected to the oil pump OP via a branching path Pb, which will be described later.

[0027] Furthermore, the motor case 10 has a lid member 13 that is joined to the cover member 12. The lid member 13 is located on the side opposite to the case member 11 in the rotation axis X direction when viewed from the cover member 12.

[0028] The cover member 13 has a wall portion 130 perpendicular to the rotation axis X. In the wall portion 130, the drive shaft DB penetrates in the direction of the rotation axis X in the region where the rotation axis X intersects. The wall portion 130 is provided with a cylindrical drive shaft support portion 135 that surrounds the drive shaft DB.

[0029] The drive shaft support portion 135 is provided on the wall portion 130 facing the cover member 12. A bearing B5 is supported on the inner circumference of the drive shaft support portion 135. The outer circumference of the drive shaft DB is supported by the drive shaft support portion 135 via the bearing B5.

[0030] The gear case 14 includes a first case member 15, a second case member 16, and a cover member 17. The first case member 15, the second case member 16, and the cover member 17 are joined in this order along the rotation axis X direction. The first case member 15 is joined to the motor case 10. The second case member 16 is joined to the first case member 15 from the side opposite to the motor case 10, and the cover member 17 is joined to the second case member 16 from the side opposite to the first case member 15.

[0031] The first case member 15 has a support wall portion 151 that surrounds the rotating shaft X. The first planetary gear 4 of the power transmission mechanism 3 is housed inside the support wall portion 151. The first case member 15 is provided with a wall portion 150 that extends inward from the support wall portion 151 between the motor 2 and the first planetary gear 4.

[0032] In the wall portion 150, a cylindrical motor support portion 155 is provided in the region where the rotation axis X intersects. The other end 20b of the motor shaft 20 of the motor 2 passes through the motor support portion 155 in the direction of the rotation axis X. A bearing B2 is supported on the inner circumference of the motor support portion 155. The outer circumference of the motor shaft 20 is supported by the motor support portion 155 via the bearing B2.

[0033] The space within the housing HS is divided into two sections by the wall 150. The space on the motor 2 side (right side in the figure), as viewed from the wall 150, is the motor room Sa (second housing room) that houses the motor 2. The space on the first planetary gear 4 side (left side in the figure), as viewed from the wall 150, is the gear room Sb (first housing room) that houses the power transmission mechanism 3.

[0034] Furthermore, the wall portion 150 is provided with through holes 150a that penetrate in the direction of the rotation axis X. Multiple through holes 150a are provided at intervals in the circumferential direction around the rotation axis X. The motor chamber Sa and the gear chamber Sb are in communication with each other through the through holes 150a. As a result, the oil OL and air inside the housing HS can move between the motor chamber Sa and the gear chamber Sb.

[0035] The second case member 16 is joined to the support wall portion 151 of the first case member 15 from the opposite side of the motor case 10. The second case member 16 has a peripheral wall portion 161 that surrounds the rotating shaft X. The peripheral wall portion 161 is provided with a wall portion 160 that extends inward between the first planetary gear 4 and the second planetary gear 5. The first planetary gear 4 of the power transmission mechanism 3 is housed in the space sandwiched between the wall portion 150 of the first case member 15 and the wall portion 160 of the second case member 16.

[0036] In the wall portion 160, a cylindrical carrier support portion 165 is provided in the region where the rotation axis X intersects. The cylindrical portion 552 of the carrier 55 of the second planetary gear 5, which will be described later, is inserted into and passes through the carrier support portion 165 from the direction of the rotation axis X. A bearing B3 is supported on the inner circumference of the carrier support portion 165. The outer circumference of the cylindrical portion 552 of the carrier 55 is supported by the carrier support portion 165 via the bearing B3.

[0037] A cover member 17 is joined to the peripheral wall portion 161 of the second case member 16 from the opposite side of the first case member 15. The cover member 17 has a wall portion 170 perpendicular to the rotation axis X and a peripheral wall portion 175 surrounding the outer circumference of the wall portion 170. The cover member 17 is joined to the second case member 16 with the opening of the peripheral wall portion 175 facing the second case member 16. In this state, the opening of the peripheral wall portion 175 is closed by the second case member 16. The second planetary gear 5 and the differential mechanism 6 of the power transmission mechanism 3 are housed in the space enclosed by the second case member 16 and the cover member 17.

[0038] As shown in Figure 3, the peripheral wall portion 175 of the cover member 17 is composed of four wall portions with different outer diameters (first wall portion 171, second wall portion 172, third wall portion 173, and fourth wall portion 174). These first wall portion 171, second wall portion 172, third wall portion 173, and fourth wall portion 174 are formed continuously in this order from the second case member 16 side toward the wall portion 170 side in the direction of the rotation axis X.

[0039] The first wall portion 171 is provided so as to surround the large-diameter gear portion 531 of the stepped pinion gear 53 of the second planetary gear 5. The first wall portion 171 is joined to the peripheral wall portion 161 of the second case member 16.

[0040] The second wall portion 172 is ring-shaped and surrounds the small-diameter gear portion 532. The outer diameter of the second wall portion 172 is smaller than the outer diameter of the first wall portion 171. The first wall portion 171 and the second wall portion 172 are connected via a connecting wall portion 179 that is perpendicular to the rotation axis X. Furthermore, the second wall portion 172 is provided in a range that crosses the small-diameter gear portion 532 in the direction of the rotation axis X and extends to the outer diameter side of the pinion mate shaft 61 of the differential mechanism 6, which will be described later.

[0041] The third wall portion 173 has a tapered shape that tapers in diameter from the second wall portion 172 toward the fourth wall portion 174. The fourth wall portion 174 has a ring shape that surrounds the support portion 602 of the differential case 60. The fourth wall portion 174 is connected to the wall portion 170 at an end portion on the side opposite to the third wall portion 173.

[0042] As shown in FIG. 1, the motor 2 includes a motor shaft 20, a cylindrical rotor core 21 externally inserted into the motor shaft 20, a stator core 22 surrounding the outer periphery of the rotor core 21, and a coil 23 provided in the stator core 22. The stator core 22 is fixed to the inner periphery of the support wall portion 111 of the case member 11.

[0043] Through holes 205 and 206 penetrating the motor shaft 20 in the radial direction are provided on one end 20a side and the other end 20b side of the motor shaft 20. The through hole 205 is provided between the rotor core 21 and the motor support portion 125. The through hole 206 is provided between the rotor core 21 and the motor support portion 155.

[0044] As shown in FIG. 2, the motor shaft 20 is a hollow cylindrical member, and the drive shaft DB penetrates therethrough. A gap CL1 between the inner peripheral surface 201 of the motor shaft 20 and the outer peripheral surface DBa of the drive shaft DB communicates with an oil hole Ha on the inner diameter side of the motor support portion 125. Although details will be described later, the oil OL supplied from the oil hole Ha flows into the gap CL1, moves in the direction of the rotation axis X, and is then jetted radially outward from the through holes 205 and 206.

[0045] A cylindrical connecting portion 411 extending from the sun gear 41 of the first planetary gear 4 is inserted on the other end 20b side of the motor shaft 20. The motor shaft 20 and the connecting portion 411 are connected so as not to be relatively rotatable by spline fitting.

[0046] The first planetary gear 4 includes a sun gear 41, a ring gear 42, pinion gears 43, pinion shafts 44, and a carrier 45. In the first planetary gear 4, the sun gear 41 serves as an input portion of the output rotation of the motor 2. The carrier 45 supporting the pinion shafts 44 serves as an output portion of the input rotation.

[0047] The sun gear 41 is provided so as to be relatively rotatable with respect to the drive shaft DB while being externally inserted into the drive shaft DB. The ring gear 42 is fixed to the inner circumference of the support wall portion 151 of the first case member 15. The pinion gear 43 meshes with the outer circumference of the sun gear 41 and the inner circumference of the ring gear 42. The pinion gear 43 is rotatably supported by the pinion shaft 44. The carrier 45 has a pair of side plate portions 451 and 452 that support the end on the motor 2 side and the end on the second planetary gear 5 side of the pinion shaft 44.

[0048] A cylindrical connecting portion 453 is provided on the side plate portion 452 located on the second planetary gear 5 side. In the side plate portion 452, the connecting portion 453 protrudes in the direction approaching the second planetary gear 5 (left direction in the figure) along the rotation axis X. The connecting portion 453 is externally inserted into a cylindrical connecting portion 511 extending from the sun gear 51 of the second planetary gear 5. The connecting portion 453 and the connecting portion 511 are connected so as not to be relatively rotatable by spline fitting.

[0049] [[ID=^]] As shown in FIG. 3, the connecting portion 511 is provided with a through hole 515 that penetrates the connecting portion 511 in the radial direction of the rotation axis X. The through hole 515 is provided at the connection portion of the connecting portion 511 with the sun gear 51. Although details will be described later, a part of the oil OL that moves in the rotation axis X direction in the gap CL1 (see FIG. 2) flows into the gap CL2 between the sun gear 51 and the drive shaft DB and is jetted radially outward from the through hole 515.

[0050] The second planetary gear 5 includes a sun gear 51, a ring gear 52, a stepped pinion gear 53, a pinion shaft 54, and a carrier 55. In the second planetary gear 5, the sun gear 51 serves as an input portion of the output rotation of the first planetary gear 4. The carrier 55 that supports the pinion shaft 54 serves as an output portion of the input rotation. /

[0051] The sun gear 51 is provided so as to be relatively rotatable with respect to the drive shaft DB while being externally inserted into the drive shaft DB. The sun gear 51 meshes with the large-diameter gear portion 531 of the stepped pinion gear 53 so as to be rotationally transmissible.

[0052] The stepped pinion gear 53 has a large-diameter gear portion 531 that meshes with the sun gear 51, and a small-diameter gear portion 532 that is smaller in diameter than the large-diameter gear portion 531. The stepped pinion gear 53 is a gear component in which the large-diameter gear portion 531 and the small-diameter gear portion 532 are arranged side by side in the direction of the rotation axis X1, which is parallel to the rotation axis X, and are provided as a single unit. The small-diameter gear portion 532 is located on the differential mechanism 6 side (left side in the figure) when viewed from the large-diameter gear portion 531.

[0053] The pinion shaft 54 ​​passes through the large-diameter gear portion 531 and the small-diameter gear portion 532 of the stepped pinion gear 53 in the direction of the rotation axis X1. A needle bearing NB is provided between the stepped pinion gear 53 and the pinion shaft 54. The stepped pinion gear 53 is rotatably mounted on the pinion shaft 54 ​​via the needle bearing NB.

[0054] One end and the other end of the pinion shaft 54 ​​in the longitudinal direction are supported by a side plate portion 651 formed integrally with the differential case 60 and a side plate portion 551 arranged at intervals from the side plate portion 651. Between the side plate portions 651 and 551, multiple stepped pinion gears 53 are provided at predetermined intervals (for example, three) in the circumferential direction around the rotation axis X.

[0055] Each of the small-diameter gear sections 532 meshes with the inner circumference of the ring gear 52. The ring gear 52 is spline-fitted to the inner circumference of the second wall 172 of the cover member 17. The relative rotation of the ring gear 52 with respect to the cover member 17 is restricted.

[0056] A cylindrical portion 552 surrounding the rotating shaft X is provided on the inner diameter side of the side plate portion 551. The cylindrical portion 552 extends in a direction away from the differential mechanism 6 along the rotating shaft X. The cylindrical portion 552 is rotatably supported on the inner circumference of the carrier support portion 165 of the second case member 16 via a bearing B3.

[0057] In the second planetary gear 5, one of the side plate portions 551 and 651 that constitute the carrier 55, the side plate portion 651, is integrally formed with the differential case 60 of the differential mechanism 6. In the differential case 60, cylindrical support portions 601 and 602 are provided on both sides in the direction of the rotation axis X (left and right direction in the figure). The support portions 601 and 602 extend along the rotation axis X in a direction away from the pinion mate shaft 61.

[0058] A connecting piece 56 is provided on the outer diameter side of the support portion 601, connecting the side plate portion 651 of the carrier 55 to the side plate portion 551. The connecting piece 56 is positioned to avoid interference with the stepped pinion gear 53. As described above, multiple stepped pinion gears 53 are provided at predetermined intervals in the circumferential direction around the rotation axis X (for example, three). The connecting piece 56 is provided between adjacent stepped pinion gears 53 in the circumferential direction around the rotation axis X.

[0059] The outer circumference of the support portion 602 is rotatably supported on the inner circumference of the fourth wall portion 174 of the cover member 17 via the bearing B4.

[0060] In the second planetary gear 5, the output rotation of the motor 2, which has been reduced by the first planetary gear 4, is input to the sun gear 51 from the connecting part 453. The output rotation input to the sun gear 51 is then input to the stepped pinion gear 53 via the large-diameter gear part 531 that meshes with the sun gear 51, causing the stepped pinion gear 53 to rotate around the rotation axis X1.

[0061] In the stepped pinion gear 53, the small-diameter gear portion 532 meshes with the ring gear 52. Therefore, when the small-diameter gear portion 532 rotates around the rotation axis X1, the stepped pinion gear 53 rotates on its own axis around the rotation axis X1 while revolving around the rotation axis X. The differential case 60, which is formed integrally with the carrier 55, rotates around the rotation axis X in conjunction with the revolution of the stepped pinion gear 53.

[0062] In this stepped pinion gear 53, the outer diameter of the small-diameter gear portion 532 is smaller than the outer diameter of the large-diameter gear portion 531 (see Figure 3). Therefore, the rotation input to the sun gear 51 of the second planetary gear 5 is significantly reduced by the stepped pinion gear 53 and output to the differential case 60.

[0063] The differential case 60 is a hollow member having an internal space capable of housing the pinion mate shaft 61, the pinion gears 62, 62, and the side gears 63, 63. Inside the differential case 60, the pinion mate shaft 61 is supported by the differential case 60 in a direction perpendicular to the axis of rotation X. The pinion gears 62, 62 are rotatably supported on the pinion mate shaft 61. When the differential case 60 rotates around the axis of rotation X, the pinion gears 62, 62 rotate together with the differential case 60 around the axis of rotation X.

[0064] Inside the differential case 60, pinion gears 62, 62 and side gears 63, 63 connected to drive shafts DA, DB are meshed in a rotationally transmittable manner. When the differential case 60 rotates around the rotation axis X, the rotation of the differential case 60 is transmitted to the left and right drive shafts DA, DB via the pinion gears 62, 62 and the side gears 63, 63.

[0065] Thus, in the drive unit 1, the output rotation of the motor 2 is reduced by the first planetary gear 4 and the second planetary gear 5 and input to the differential mechanism 6, and then output to the left and right drive wheels (not shown) of the vehicle via the drive shafts DA and DB.

[0066] Here, as shown in Figure 1, in the drive unit 1, power to drive the motor 2 is supplied from the inverter 7. The inverter 7 has a circuit board 71, a plurality of capacitors 72, an input terminal 73, and an output terminal 74. The capacitors 72, the input terminal 73, and the output terminal 74 are electrically connected via the circuit board 71. The input terminal 73 and the output terminal 74 are located on one side and the other side of the capacitor 72 in the direction of the rotation axis X.

[0067] The input terminal 73 is electrically connected to the vehicle's battery BT via the power supply line PN. The output terminal 74 is electrically connected to the coil 23 of the motor 2 via the busbar Bs.

[0068] The DC current from the battery BT is input to the inverter 7 from the input terminal 73. It is then converted to three-phase AC by the capacitor 72, and output to the coil 23 via the busbar Bs from the output terminal 74. The busbar Bs consists of three wires corresponding to the U, V, and W phases (see Figure 5).

[0069] When power is supplied to coil 23, a magnetic field is generated around stator core 22. This causes rotor core 21 and motor shaft 20 to rotate around rotation axis X, driving motor 2.

[0070] The inverter 7's circuit board 71, capacitor 72, input terminal 73, and output terminal 74 are housed in the inverter case 8. The inverter case 8 is located above the motor case 10 and gear case 14, straddling the motor case 10 and gear case 14. In housing HS, the inverter case 8 is located at the highest position.

[0071] Figure 4 is a diagram illustrating the inverter case 8. Figure 5 is a diagram illustrating the inverter case 8. Figure 5 is a schematic diagram of the A-A cross-section in Figure 4. In Figure 5, the power supply line PN is partially cut out to expose the drain hole H3. Figure 6 is a diagram illustrating the breather chamber Sd. Figure 7 is a diagram illustrating the breather chamber Sd. Figure 7 is a schematic diagram of the A-A cross-section in Figure 6.

[0072] As shown in Figure 4, the inverter case 8 has a bottomed housing portion 80 with an opening facing upward, and a plate-shaped cover portion 85 that closes the opening of the housing portion 80. The inverter case 8 is provided in a range in the rotation axis X direction, extending from the cover member 12 side of the motor case 10 to the cover member 17 side of the gear case 14.

[0073] The housing portion 80 has a bottom wall portion 81 that supports the circuit board 71 of the inverter 7, and a peripheral wall portion 82 that surrounds the outer periphery of the bottom wall portion 81. The housing portion 80 also has a partition wall 83 (barrier) that divides the space enclosed by the peripheral wall portion 82. The partition wall 83 is set to a height that is approximately aligned with the peripheral wall portion 82 in the vertical direction.

[0074] As shown in Figure 5, the peripheral wall portion 82 has a substantially rectangular shape when viewed from above. The peripheral wall portion 82 has long wall portions 821 and 822 provided in a direction along the rotation axis X, and short wall portions 823 and 824 connecting the ends of the long wall portions 821 and 822. The partition wall 83 is provided in a direction perpendicular to the rotation axis X. The partition wall 83 is provided between the short wall portions 823 and 824, closer to the short wall portion 824. One end and the other end of the partition wall 83 are connected to the long wall portions 821 and 822.

[0075] In the inverter case 8, the area enclosed by the long walls 821 and 822, the short wall 823, and the partition wall 83 of the housing portion 80 constitutes the inverter room Sc (third housing room) for housing the inverter 7. The area enclosed by the long walls 821 and 822, the short wall 824, and the partition wall 83 constitutes the breather room Sd (fourth housing room). The inverter room Sc has a larger volume than the breather room Sd.

[0076] As shown in Figure 6, a through-hole 83a (first passage) is formed in the partition wall 83, penetrating in the direction of the rotation axis X. Inside the inverter case 8, the inverter chamber Sc and the breather chamber Sd are in communication through the through-hole 83a.

[0077] Two through-holes 824a and 824b are formed in the short wall portion 824, penetrating in the direction of the rotation axis X. The through-holes 824a and 824b are positioned offset from each other in the vertical direction. The breather 9 (second passage) is inserted into the upper through-hole 824a from the outside of the inverter case 8. The power supply line PN is inserted into the lower through-hole 824b from the outside of the inverter case 8. The upper through-hole 824a is a communication hole that connects the breather chamber Sd to the outside. The breather 9 inserted into the through-hole 824a constitutes a passage that connects the breather chamber Sd to the outside.

[0078] The breather 9 includes a breather pipe 91 inserted into a through hole 824a and a filter 90 that closes the opening of the breather pipe 91. The breather chamber Sd communicates with the outside through the breather 9. The breather 9 may also be configured without the breather pipe 91. For example, the filter 90 may be directly provided in the through hole 824a of the short wall portion 824.

[0079] As shown in Figure 4, in the drive unit 1 according to this embodiment, a single breather passage 900 is formed by the through-hole 83a of the partition wall 83, the breather chamber Sd, and the breather 9. That is, the breather passage 900 includes the through-hole 83a of the partition wall 83 and the breather 9.

[0080] As shown in Figure 4, the bottom wall portion 81 of the inverter case 8 is in contact with the upper surface of the motor case 10 and the upper surface of the gear case 14. Specifically, on the motor case 10 side, the bottom wall portion 81 is in contact with the upper surface 111c of the support wall portion 111 of the case member 11. On the gear case 14 side, the bottom wall portion 81 is in contact with the upper surface 151c of the support wall portion 151 of the first case member 15, the upper surface 161c of the peripheral wall portion 161 of the second case member 16, and the upper surface 171c of the first wall portion 171 of the cover member 17. The inverter case 8 is fixed to the motor case 10 and the gear case 14 by bolts (not shown).

[0081] When the inverter case 8 is viewed from above, the short wall portion 823 of the peripheral wall portion 82 overlaps with the wall portion 120 of the cover member 12. The short wall portion 824 overlaps with the third wall portion 173 of the cover member 17. The partition wall 83 overlaps with the connecting wall portion 179 of the cover member 17.

[0082] The breather chamber Sd protrudes from the connecting wall portion 179 of the cover member 17 toward the second wall portion 172 (left side in the figure). In the vertical direction, the breather chamber Sd faces the second wall portion 172 of the cover member 17 with a gap R between them.

[0083] The breather chamber Sd overlaps with the inverter chamber Sc when viewed from the direction of the rotation axis X, and overlaps with the gear chamber Sb when viewed from the radial direction of the rotation axis X. The breather chamber Sd is provided with a drain pipe 89 (oil return passage), which will be described later. The drain pipe 89 penetrates the second wall portion 172 of the cover member 17 and connects to the gear chamber Sb.

[0084] In this case, if a breather chamber Sd is not provided, a stepped portion D1 exists in the drive unit 1 in the area where the partition wall 83 constituting the inverter chamber Sc and the connecting wall portion 179 and the second wall portion 172 of the cover member 17 constituting the gear chamber Sb are located. That is, there is spatial room above the gear chamber Sb, in the area (stepped portion D1) that overlaps with the inverter chamber Sc when viewed from the direction of the rotation axis X. Therefore, the area where the stepped portion D1 is provided tends to become dead space. In this embodiment, by arranging the breather chamber Sd in the stepped portion D1, the dead space is effectively utilized, and the drive unit 1 is prevented from becoming larger in the axial and radial directions of the rotation axis X.

[0085] In the inverter chamber Sc, a through hole 81a is provided on the cover member 12 side (right side in the figure) of the bottom wall portion 81. The through hole 81a penetrates the bottom wall portion 81 in the vertical direction. In the peripheral wall portion 121 of the cover member 12, a through hole 121a is formed in the portion opposite to the through hole 81a, and penetrates in the vertical direction. In addition, a cylindrical portion 122 is formed in the peripheral wall portion 121, surrounding the through hole 121a.

[0086] The cylindrical portion 122 protrudes upward from the peripheral wall portion 121. The upper end 122a of the cylindrical portion 122 is joined to the bottom wall portion 81. Therefore, the motor chamber Sa and the inverter chamber Sc are in communication with each other through the through holes 121a and 81a. The busbar Bs is provided spanning the motor chamber Sa and the inverter chamber Sc, passing through the through holes 121a and 81a.

[0087] Furthermore, drain holes H1 and H2 are formed in the wall portion separating the inverter chamber Sc and the motor chamber Sa (the support wall portion 111 of the case member 11, the bottom wall portion 81 of the inverter case 8, and the substrate 71), which connect the motor chamber Sa and the inverter chamber Sc.

[0088] The drain holes H1 and H2 are oriented along the vertical direction. When viewed from above, the drain holes H1 and H2 are positioned to overlap with the coil ends 23a and 23b of the motor 2.

[0089] The breather chamber Sd is provided with a drain hole H3 that penetrates the bottom wall portion 81 in the vertical direction. A drain pipe 89 is inserted into the drain hole H3. As shown in Figure 7, the drain pipe 89 is oriented along a vertical line VL passing through the rotation axis X. The upper end 89a of the drain pipe 89 is inserted into the drain hole H3 in the bottom wall portion 81, and the lower end 89b is inserted into a through hole 172a that penetrates the second wall portion 172 of the cover member 17. Therefore, the breather chamber Sd is in communication with the gear chamber Sb via the drain pipe 89. Note that Figure 7 illustrates the case where the bottom wall portion 81 of the breather chamber Sd is perpendicular to the vertical line VL, but it is not limited to this shape. For example, the bottom wall portion 81 of the breather chamber Sd may be inclined in a direction in which the vertical position in the figure decreases as it moves from the long wall portions 821 and 822 toward the drain hole H3.

[0090] As shown in Figure 3, the drain pipe 89 penetrates the second wall portion 172 at a position where it overlaps with the pinion mate shaft 61 of the differential mechanism 6 when viewed from above. In the direction of the rotation axis X, the drain pipe 89 is offset from the stepped pinion gear 53.

[0091] As shown in Figure 5, when viewed from above, the output terminal 74 and input terminal 73 on the inverter 7's circuit board 71 are positioned to overlap with the rotation axis X. The output terminal 74 and input terminal 73 are offset from each other in the direction of the rotation axis X. Multiple capacitors 72 are positioned between the input terminal 73 and the output terminal 74. The inverter 7 (circuit board 71) is housed in the inverter chamber Sc with the output terminal 74 facing the short wall portion 823 side of the peripheral wall portion 82 (right side in the figure) and the input terminal 73 facing the partition wall 83 side (left side in the figure). In this state, the output terminal 74 of the inverter 7 is connected to the busbar Bs which penetrate vertically through the through hole 81a of the bottom wall portion 81. The input terminal 73 penetrates the through hole 83a of the partition wall 83 in the direction of the rotation axis X, with the tip end connection portion 73a protruding into the breather chamber Sd.

[0092] The connection portion 73a of the input terminal 73 penetrates the through-hole 83a of the partition wall 83 in the direction of the rotation axis X. In this state, the input terminal 73 is positioned with a gap between it and the inner circumference of the through-hole 83a that allows air to pass through. Furthermore, the connection portion 73a of the input terminal 73 protrudes into the breather chamber Sd. The connector portion PNa (external connection terminal) of the power supply line PN is connected to the connection portion 73a of the input terminal 73.

[0093] As shown in Figure 6, the power supply line PN penetrates the short wall portion 824 from the outside of the inverter case 8. The connector portion PNa of the power supply line PN is connected to the connection portion 73a of the input terminal 73 of the inverter 7 inside the breather chamber Sd.

[0094] As shown in Figure 4, the lid portion 85 is provided with a rib 86 on the surface 851 facing the bottom wall portion 81. The rib 86 protrudes into the interior of the inverter chamber Sc. The rib 86 is oriented along the rotation axis X direction. The rib 86 extends from one end surface 85a on the short wall portion 823 side of the peripheral wall portion 82 toward the partition wall portion 83 side (left side in the figure). The rib 86 is provided in a range that crosses the area where the drain holes H1 and H2 are provided in the rotation axis X direction.

[0095] An oil passage 87 is formed inside the rib 86. The oil passage 87 is a blind hole oriented along the rotation axis X. The oil passage 87 opens to one end face 85a of the cover portion 85 in the direction of the rotation axis X. The oil passage 87 is connected to the oil pump OP (see Figure 1) via the supply passage Pa, which will be described later.

[0096] The rib 86 is provided with discharge holes 871 and 872 that connect the oil passage 87 and the inverter chamber Sc. The discharge holes 871 and 872 are positioned opposite the capacitor 72 in the vertical direction. In this embodiment, an example is shown in which the oil passage 87 is provided with two discharge holes 871 and 872, but the number of discharge holes is not particularly limited and may be one or three or more.

[0097] As shown in Figure 1, the motor chamber Sa stores oil OL for cooling the motor 2. The gear chamber Sb stores oil OL for lubricating the power transmission mechanism 3. The oil OL in the motor chamber Sa and the oil OL in the gear chamber Sb can flow through each other via the through-hole 150a in the wall portion 150. The oil levels of the oil OL in the motor chamber Sa and the oil OL in the gear chamber Sb are aligned via the through-hole 150a.

[0098] In the drive unit 1 according to this embodiment, the oil OL stored in the motor chamber Sa is filtered by the strainer ST, then sucked and pressurized by the oil pump OP and supplied to each part.

[0099] A portion of the oil OL pressurized by the oil pump OP is delivered through the supply passage Pa to an oil passage 87 located in the lid 85 of the inverter case 8. As shown in Figure 4, the oil OL delivered from the supply passage Pa to the oil passage 87 is injected from the discharge holes 871 and 872 toward the inverter 7. This cools the substrate 71 and capacitor 72 of the inverter 7.

[0100] The oil OL that cools the inverter 7 is drained through drain holes H1 and H2. The oil OL drained from drain holes H1 and H2 cools the coil ends 23a and 23b from the outer diameter side, and then moves by its own weight to the lower part of the motor chamber Sa where it is stored.

[0101] Furthermore, as shown in Figure 1, a portion of the oil OL pressurized by the oil pump OP is discharged through a branch path Pb that branches off from the supply path Pa, and through an oil hole Ha provided in the motor support portion 125 of the cover member 12.

[0102] As shown in Figure 2, a portion of the oil OL released from the oil hole Ha lubricates the bearings B1 and B5. In addition, a portion of the oil OL released from the oil hole Ha is pushed by the oil OL released sequentially from the oil hole Ha and is delivered to the power transmission mechanism 3 through the gap CL1 between the motor shaft 20 and the drive shaft DB.

[0103] A portion of the oil OL passing through the gap CL1 between the motor shaft 20 and the drive shaft DB is injected outwards from the through holes 205 and 206 of the motor shaft 20. This cools the coil ends 23a and 23b of the motor 2 from the inner side. After cooling the coil ends 23a and 23b, the oil OL injected from the through holes 205 and 206 is stored in the motor chamber Sa.

[0104] Furthermore, the oil OL that was not injected from the through holes 205 and 206 is transported across the inside of the sun gear 41 of the first planetary gear 4 to the second planetary gear 5 side. As shown in Figure 3, a portion of the oil OL transported to the second planetary gear 5 side passes through the gap CL2 between the sun gear 51 and the drive shaft DB and is injected outwards from the through hole 515 of the connecting portion 511. This lubricates the meshing portion between the large-diameter gear portion 531 and the sun gear 51. After lubricating the meshing portion between the large-diameter gear portion 531 and the sun gear 51, the oil OL injected from the through hole 515 is stored in the gear chamber Sb. The remaining oil OL that was not injected from the through hole 515 proceeds further to the differential mechanism 6 side and lubricates the thrust bearing SB between the sun gear 51 and the differential case 60.

[0105] Furthermore, as shown in Figure 3, the oil OL stored in the gear chamber Sb is set to a height such that at least the connecting piece 56 and the stepped pinion gear 53 are located in the oil OL when one end 61a or the other end 61b of the pinion mate shaft 61 is in its lowest position.

[0106] Therefore, when the stepped pinion gear 53 rotates, the oil OL stored in the lower part of the gear case 14 is greatly stirred up. As a result, each meshing part in the power transmission mechanism 3 is lubricated overall.

[0107] As described above, the drive unit 1 according to this embodiment connects the motor chamber Sa, the gear chamber Sb, and the inverter chamber Sc, and cools and lubricates the motor 2, the power transmission mechanism 3, and the inverter 7 with a common oil OL (see Figure 1).

[0108] As shown in Figure 4, a portion of the oil OL stirred up by the rotation of the motor 2 and the power transmission mechanism 3 becomes a mist-like oil mist OM in the motor chamber Sa and the gear chamber Sb. In addition, a portion of the oil OL sprayed from the oil passage 87 of the inverter case 8 toward the inverter 7 bounces back, becoming a mist-like oil mist OM in the inverter chamber Sc. Furthermore, oil mist OM that has risen through the through hole 81a from the motor chamber Sa side enters the inverter chamber Sc. When oil mist OM is generated, the pressure in the motor chamber Sa, gear chamber Sb, and inverter chamber Sc tends to rise.

[0109] In the drive unit 1, a breather 9 for releasing the increased pressure to the atmosphere is installed in the inverter case 8, which is located away from rotating parts such as the motor 2 and the power transmission mechanism 3. Therefore, it is difficult for the oil OL, which has been stirred up into a foamy state by the rotation of the motor 2 and the power transmission mechanism 3, to enter the breather 9.

[0110] Here, the inverter chamber Sc is located at a higher position than the motor chamber Sa and the gear chamber Sb. Therefore, the oil mist OM inside the housing HS tends to rise and accumulate in the inverter chamber Sc.

[0111] In this case, for example, if the breather 9 in the inverter case 8 is installed near the through hole 81a in the peripheral wall portion 82 that constitutes the inverter room Sc (for example, in the short wall portion 823), oil mist OM may enter the breather 9, and oil OL may be ejected from the breather 9 to the outside of the housing HS. Therefore, in this embodiment, a partition wall 83 is provided in the inverter case 8 at a position away from the through hole 81a to form a breather room Sd as a space separated from the inverter room Sc. The breather 9 is then installed in the wall portion that constitutes the breather room Sd (the wall portion located away from the partition wall 83).

[0112] Figure 8 illustrates the airflow Ar within the inverter case 8. As shown in Figure 8, the inverter chamber Sc and the breather chamber Sd are separated by a partition wall 83 within the inverter case 8. Therefore, most of the oil mist OM remains within the inverter chamber Sc.

[0113] Here, the breather chamber Sd and the inverter chamber Sc are in communication through a through-hole 83a in the partition wall 83. An input terminal 73 is inserted into the through-hole 83a. Air Ar can flow between the breather chamber Sd and the inverter chamber Sc through a small gap between the outer circumference of the input terminal 73 and the inner circumference of the through-hole 83a.

[0114] When the pressure inside the inverter chamber Sc rises, the air Ar inside the inverter chamber Sc is released to the breather chamber Sd through the gap between the through-hole 83a and the input terminal 73. The air Ar released into the breather chamber Sd is then released to the atmosphere through the breather 9 that connects the breather chamber Sd to the outside (see the white arrow in the figure). As a result, the pressure that has risen in the inverter chamber Sc is released to the atmosphere. Also, the driving of the drive unit 1 increases the pressure inside the motor chamber Sa and the gear chamber Sb (see Figure 1). Since the motor chamber Sa and the inverter chamber Sc are connected via the through-hole 81a, the pressure inside the inverter chamber Sc also rises. In this case, the pressure inside the inverter chamber Sc is released to the breather chamber Sd through the small gap between the outer circumference of the input terminal 73 and the inner circumference of the through-hole 83a in the partition wall 83, and then released to the atmosphere through the breather 9 provided in the breather chamber Sd.

[0115] At this time, an airflow (Ar) of air is generated inside the inverter case 8, passing through the through-hole 83a from the inverter room Sc to the breather room Sd. The oil mist OM inside the inverter room Sc is carried by the airflow of Ar towards the breather room Sd. However, much of the oil mist OM heading towards the breather room Sd collides with the partition wall 83, thus restricting its movement beyond the partition wall 83 towards the breather room Sd.

[0116] Therefore, in the inverter case 8, the breather chamber Sd maintains a drier environment with less oil than the inverter chamber Sc. As a result, it is difficult for oil OL to enter the breather 9. In this way, by separating the breather chamber Sd and the inverter chamber Sc with the partition wall 83, the entry of oil OL (oil mist) into the breather chamber Sd is suppressed. This reduces the possibility of oil OL being ejected from the breather 9, while allowing the increased pressure inside the housing HS to be released to the outside from the breather 9.

[0117] Here, some of the oil mist OM in the inverter chamber Sc may enter the breather chamber Sd through the through-hole 83a in the partition wall 83 and the input terminal 73. In this embodiment, the distance traveled by the air Ar containing the oil mist OM within the housing HS is extended by the amount of the breather passage 900, which is composed of the through-hole 83a, the breather chamber Sd, and the breather 9. As a result, the kinetic energy of the air Ar containing the oil mist OM is attenuated as it passes through the breather passage 900, making it easier to liquefy. Therefore, some of the oil OL that has passed from the inverter chamber Sc through the through-hole 83a is caught in the breather chamber Sd. Thus, the breather chamber Sd also functions as a catch tank for the oil OL.

[0118] The oil OL caught in the breather chamber Sd moves to the bottom of the breather chamber Sd due to its own weight and is stored there. Also, some of the oil mist OM that enters the breather chamber Sd reaches the breather 9, but its discharge to the outside is prevented by the filter 90. The oil OL whose discharge to the outside is prevented moves to the bottom of the breather chamber Sd due to its own weight and is stored there.

[0119] A drain pipe 89 is provided in the area constituting the breather chamber Sd on the bottom wall 81 of the inverter case 8. The drain pipe 89 connects the breather chamber Sd and the gear chamber Sb. Therefore, oil OL accumulated at the bottom of the breather chamber Sd is discharged into the gear chamber Sb through the drain pipe 89. Here, the opening area of ​​the drain pipe 89 is larger than the opening area of ​​the gap between the outer circumference of the input terminal 73 and the inner circumference of the through hole 83a in the partition wall 83. Therefore, the amount of oil discharged from the drain pipe 89 into the gear chamber Sb is greater than the amount of oil that enters the breather chamber Sd through the gap between the outer circumference of the input terminal 73 and the inner circumference of the through hole 83a. Thus, the possibility of a large amount of oil OL accumulating in the breather chamber Sd and the accumulated oil OL being ejected to the outside from the breather 9 is reduced.

[0120] The drain pipe 89 may be discharged to the gear chamber Sb, the motor chamber Sa, or another oil tank (not shown). By discharging the drain pipe 89 to the gear chamber Sb as in this embodiment, the overall length of the drain pipe 89 can be shortened. This allows the oil OL in the breather chamber Sd to be quickly discharged to the gear chamber Sb.

[0121] As shown in Figure 3, the drain pipe 89 is connected to the second wall portion 172 of the cover member 17 at a position that overlaps with the pinion mate shaft 61 of the differential mechanism 6. As a result, the oil OL drained from the drain pipe 89 is returned to the gear chamber Sb from the upper side of the differential case 60.

[0122] Here, the oil OL stored in the gear chamber Sb is greatly scraped up by the rotation of the stepped pinion gear 53. In this case, the oil OL around the large-diameter gear portion 531 of the stepped pinion gear 53 is greatly scattered.

[0123] Therefore, for example, if the drain pipe 89 is connected to the first wall portion 171 of the cover member 17 surrounding the large-diameter gear portion 531, it is conceivable that the oil OL scraped up by the large-diameter gear portion 531 could flow back through the drain pipe 89 and enter the breather chamber Sd.

[0124] Therefore, by connecting the drain pipe 89 to the second wall portion 172 of the cover member 17 at a position that overlaps with the pinion mate shaft 61, the backflow of oil OL, which is scraped up by the rotation of the large-diameter gear portion 531, into the drain pipe 89 is reduced. As a result, a dry environment is maintained in the breather chamber Sd. In addition, a check valve may be provided on the drain pipe 89 to prevent the backflow of oil OL into the drain pipe 89.

[0125] In this way, by forming the breather chamber Sd within the same housing HS as the motor chamber Sa, gear chamber Sb, and inverter chamber Sc, it is possible to make the drive unit 1 more compact.

[0126] Figure 9 illustrates the connection of the power supply line PN to the input terminal 73 of the inverter 7. For example, when performing maintenance on the drive unit 1 during vehicle after-sales service, the power supply line PN may be disconnected from the input terminal 73 of the inverter 7.

[0127] The input terminal 73 of the inverter 7 penetrates the partition wall 83 from the inverter room Sc side to the breather room Sd side. The connection portion 73a of the input terminal 73 is located inside the breather room Sd. The connector portion PNa of the power supply line PN is connected to the connection portion 73a of the input terminal 73 inside the breather room Sd.

[0128] To remove the power supply line PN, after removing the cover 85 (see Figure 8), reach your hand into the breather chamber Sd through the upper opening of the housing 80, grasp the connector part PNa of the power supply line PN, and pull it out from the input terminal 73.

[0129] Here, the inverter 7 inside the inverter chamber Sc is slippery due to the oil OL. Therefore, if, for example, the connector part PNa of the power supply line PN and the connection part 73a of the input terminal 73 are located inside the inverter chamber Sc, the oil OL makes them slippery, making it difficult to pull out the power supply line PN and leading to a deterioration in work efficiency.

[0130] Therefore, by placing the connector PNa of the power supply line PN and the connection portion 73a of the input terminal 73 in the breather chamber Sd, which is a dry environment, the slipperiness caused by oil OL is reduced. As a result, the power supply line PN can be easily removed, improving work efficiency.

[0131] The following are examples of a drive unit 1 in a certain aspect of the present invention. (1) The drive unit 1 has a housing HS which includes a gear chamber Sb (first housing chamber) housing a power transmission mechanism 3, a motor chamber Sa (second housing chamber) housing a motor 2, an inverter chamber Sc (third housing chamber) housing an inverter 7, and a breather chamber Sd (fourth housing chamber) adjacent to the inverter chamber Sc separated by a partition wall 83. A breather passage 900 is formed including a through hole 83a (first passage) provided in the partition wall 83 and a breather 9 (second passage) provided in the breather chamber Sd.

[0132] In this embodiment, a breather passage 900 is formed that passes from a through-hole 83a in the partition wall 83 through a breather chamber Sd to the breather 9. The breather chamber Sd is located adjacent to the inverter chamber Sc, which does not have rotating parts such as the motor 2 or the power transmission mechanism 3. This configuration makes it difficult for oil OL and oil mist OM to enter the breather chamber Sd, thereby reducing the amount of oil OL ejected (discharged) to the outside of the drive unit 1. Furthermore, since the breather chamber Sd is interposed between the inverter chamber Sc and the breather 9, rather than directly installing the breather 9 in the inverter chamber Sc, the distance traveled by the air Ar flowing through the housing HS can be extended. As a result, the kinetic energy of the air Ar containing oil mist OM etc. is attenuated, making it easier to liquefy. Therefore, a portion of the oil OL that passes through the through-hole 83a from the inverter chamber Sc is caught in the breather chamber Sd. This makes it difficult for oil OL to be ejected from the breather 9, further reducing the amount of oil OL discharged to the outside of the drive unit 1. Furthermore, the motor chamber Sa, gear chamber Sb, inverter chamber Sc, and breather chamber Sd are all formed within the same housing HS. This allows the drive unit 1 to be made more compact.

[0133] (2) The breather chamber Sd houses (is provided) the connector PNa (external connection terminal) of the power supply line PN that connects to the inverter 7.

[0134] Air Ar flows from the inverter room Sc to the breather room Sd through the through-hole 83a of the partition wall 83. In this case, some of the oil mist OM contained in the air Ar is restricted from flowing into the breather room Sd by the partition wall 83 and remains in the inverter room Sc. As a result, the environment in the breather room Sd has less oil OL than the environment in the inverter room Sc. For example, when considering after-sales service (maintenance) of the power supply line PN, it is easier to work if the connector part PNa is placed in a place with less oil. Therefore, by configuring it as described above and placing the connector part PNa of the power supply line PN in the breather room Sd, workability can be improved.

[0135] (3) The breather chamber Sd has a drain pipe 89 (oil return passage) formed therein that returns oil OL to the gear chamber Sb.

[0136] With this configuration, the oil OL accumulated in the breather chamber Sd can be quickly discharged, further reducing the amount of oil OL sprayed out from the breather 9.

[0137] (4) In the vertical direction with respect to the installation state of the drive unit 1 on the vehicle, the inverter chamber Sc is located above the motor chamber Sa. The gear chamber Sb is located adjacent to the motor chamber Sa in the direction of the rotation axis X of the motor 2. The breather chamber Sd has a portion that overlaps with the inverter chamber Sc when viewed from the direction of the rotation axis X, and overlaps with the gear chamber Sb when viewed from the radial direction of the rotation axis X.

[0138] With this configuration, the breather chamber Sd can be placed in the stepped portion D1 (see Figure 4) formed by the inverter chamber Sc and the gear chamber Sb. This makes it possible to suppress the increase in size of the drive unit 1.

[0139] (5) In the vertical direction with respect to the installation state of the drive unit 1 on the vehicle, the inverter chamber Sc is located above the motor chamber Sa. The gear chamber Sb is located adjacent to the motor chamber Sa in the direction of the rotation axis X of the motor 2. The breather chamber Sd has a drain pipe 89 (oil return passage) that allows oil OL to drain from the gear chamber Sb. The breather chamber Sd has a portion that overlaps with the inverter chamber Sc when viewed from the direction of the rotation axis X, and a portion that overlaps with the gear chamber Sb when viewed from the radial direction of the rotation axis X.

[0140] This configuration allows for a reduction in the size of the drive unit 1 while also shortening the drain pipe 89.

[0141] (Modification 1) In the drive unit 1 according to the above embodiment, the drain pipe 89 is provided in a direction along the vertical direction, and an example was given in which the oil OL in the breather chamber Sd is drained to the gear chamber Sb located directly below the breather chamber Sd. However, it is not limited to draining to the gear chamber Sb. For example, it may be drained to the motor chamber Sa.

[0142] Figure 10 is a diagram illustrating the drive unit 1A according to Modification 1. In the following description, components similar to those in the embodiment will be denoted by the same reference numerals, and detailed explanations will be omitted.

[0143] As shown in Figure 10, the drive unit 1A according to the modified example 1 has a substantially L-shaped drain pipe 89A that is bent between its upper end 89a and lower end 89b. The drain pipe 89A is provided with the upper end 89a side facing vertically from the bent portion 89c, and the lower end 89b side facing along the rotation axis X.

[0144] The upper end 89a of the drain pipe 89A is connected to the breather chamber Sd. The lower end 89b of the drain pipe 89A is connected to the motor chamber Sa via the oil passage Hb. The oil passage Hb has a first oil hole Hb1 that penetrates the first wall portion 171A of the cover member 17A and the peripheral wall portion 161A of the second case member 16A in a direction along the rotation axis X, and a second oil hole Hb2 that penetrates the support wall portion 151A of the first case member 15A in a direction along the rotation axis X.

[0145] The second oil hole Hb2 is inclined downward as it moves away from the first oil hole Hb1. The second oil hole Hb2 opens into the motor chamber Sa at a position opposite the coil end 23b of the motor 2 in the direction of the rotation axis X.

[0146] The oil OL in the breather chamber Sd is drained to the motor chamber Sa through the drain pipe 89A and the oil passage Hb. The second oil hole Hb2 of the oil passage Hb is inclined downward as it moves away from the first oil hole Hb1. Therefore, the oil OL in the oil passage Hb is accelerated by its own weight as it passes through the second oil hole Hb2 and is released to the coil end 23b. This allows the coil end 23b to be cooled.

[0147] The drive unit 1A according to the modified example 1 has the following configuration: (3) A drain pipe 89A (oil return passage) for returning oil OL to the motor chamber Sa is formed in the breather chamber Sd.

[0148] With this configuration, the oil OL accumulated in the breather chamber Sd can be quickly discharged, further reducing the amount of oil OL sprayed out from the breather 9.

[0149] (Modification 2) In the above-described embodiment and Modification 1, an example was given in which the breather chamber Sd is provided at a position that overlaps with the gear chamber Sb when viewed from the radial direction of the rotating shaft X. However, the embodiment is not limited to this. For example, the breather chamber Sd may be provided at a position that overlaps with the motor chamber Sa when viewed from the radial direction of the rotating shaft X.

[0150] Figure 11 is a diagram illustrating modification 2 of drive unit 1B. Figure 11 is a schematic diagram of a cross-section obtained by cutting drive unit 1B in the same plane as Figure 5 (section A-A in Figure 4). Figure 12 is a diagram illustrating modification 2 of drive unit 1B. Figure 12 is a schematic diagram of section A-A in Figure 11. In Figure 12, the vertical line VL direction corresponds to the up and down direction in the figure.

[0151] As shown in Figure 11, in the inverter 7A of the drive unit 1B according to the modified example 2, the input terminal 73A and the output terminal 74A are provided on one side in the direction of the rotation axis X when viewed from the capacitor 72. The input terminal 73A and the output terminal 74A are provided on one side and the other side of the rotation axis X. The busbars Bs connected to the output terminal 74A, and the through holes 81a in the bottom wall portion 81A through which the busbars Bs pass, are also provided on the other side of the rotation axis X.

[0152] The peripheral wall portion 82A of the inverter case 8A surrounding the inverter 7A has a roughly rectangular shape when viewed from above. The peripheral wall portion 82A has long wall portions 821A and 822A arranged in a direction along the rotation axis X, and short wall portions 823A and 824A connecting the ends of the long wall portions 821A and 822A. The inverter case 8A also has a partition wall 83A (barrier wall) that divides the space enclosed by the peripheral wall portion 82A.

[0153] The partition wall 83A has a first wall portion 831 connected to the long wall portion 821A and oriented perpendicular to the rotation axis X, and a second wall portion 832 connected to the short wall portion 823A and oriented along the rotation axis X. The ends of the first wall portion 831 and the second wall portion 832 are connected to each other. As shown in Figure 12, the first wall portion 831 and the second wall portion 832 of the partition wall 83A are set to a height that is substantially aligned with the peripheral wall portion 82A in the vertical direction.

[0154] As shown in Figure 11, the first wall portion 831 is provided between the short wall portion 823A and the inverter 7A. The first wall portion 831 is provided in the range extending from the long wall portion 821A across the rotation axis X. The second wall portion 832 is provided between the through hole 81a of the bottom wall portion 81A and the rotation axis X.

[0155] In the inverter case 8A, the area enclosed by the long walls 821A and 822A, the short wall 824A, and the partition wall 83A (first wall 831, second wall 832) constitutes the inverter room Se (third housing room) for housing the inverter 7A. In addition, the area enclosed by the long wall 821A, the short wall 823A, and the partition wall 83A (first wall 831, second wall 832) constitutes the breather room Sf (fourth housing room).

[0156] As shown in Figure 12, in the vertical direction relative to the installation state of the drive unit 1B on the vehicle, the breather chamber Sf is located above the motor chamber Sa. The breather chamber Sf is located in the stepped portion D2, which is a dead space formed by the inverter chamber Se and the motor chamber Sa. Therefore, even if the breather chamber Sf is provided in the inverter case 8A, it is difficult to increase the size of the drive unit 1B.

[0157] Therefore, as shown in Figure 11, the breather chamber Sf overlaps with the inverter chamber Se when viewed from the direction of the rotation axis X, and as shown in Figure 12, it has a portion that overlaps with the motor chamber Sa when viewed from the radial direction of the rotation axis X.

[0158] As shown in Figure 11, a through-hole 831a is formed in the first wall portion 831 of the partition wall 83A. The inverter room Se and the breather room Sf are in communication through the through-hole 831a. In addition, a breather 9 (see dashed line in the figure) and a power supply line PN pass through the area constituting the breather room Sf of the short wall portion 823A from the outside of the inverter case 8A. The breather 9 and the power supply line PN are installed with a vertical offset from each other (see Figure 12).

[0159] As shown in Figure 12, a drain pipe 89B penetrates the region constituting the breather chamber Sf of the bottom wall portion 81A. The drain pipe 89B is oriented along a vertical line VL passing through the rotation axis X.

[0160] The drain pipe 89B is located on the opposite side of the cylindrical portion 122 surrounding the busbar Bs, with the vertical line VL in between. The upper end 89a of the drain pipe 89B opens into the breather chamber Sf, and the lower end 89b penetrates the peripheral wall portion 121 of the cover member 12 and opens into the motor chamber Sa. Therefore, the breather chamber Sf is in communication with the motor chamber Sa via the drain pipe 89B.

[0161] As shown in Figure 11, the connection portion 73a of the input terminal 73A penetrates the through-hole 831a of the first wall portion 831 of the partition wall 83A from the inverter room Se side to the breather room Sf side. Inside the breather room Sf, the connector portion PN of the power supply line PN is connected to the connection portion 73a of the input terminal 73A.

[0162] In the inverter case 8A, the inverter chamber Se and the breather chamber Sf are separated by a partition wall 83A. As a result, most of the oil mist OM remains in the inverter chamber Se. Consequently, in the inverter case 8A, the breather chamber Sf maintains a drier environment with less oil than the inverter chamber Se. Therefore, it is difficult for oil to enter the breather 9.

[0163] Furthermore, as shown in Figure 12, the oil OL accumulated at the bottom of the breather chamber Sf is quickly drained to the motor chamber Sa through the drain pipe 89B. As a result, the amount of oil OL discharged into the motor chamber Sa is greater than the amount flowing in from the inverter chamber Se. Therefore, the accumulation of a large amount of oil OL in the breather chamber Sf reduces the likelihood of oil OL being ejected from the breather 9.

[0164] In this way, by separating the breather chamber Sf from the inverter chamber Se with the partition wall 83A, the amount of oil OL sprayed from the breather 9 can be reduced while releasing the increased pressure.

[0165] The drive unit 1B according to the modified example 2 has the following configuration: (4) In the vertical direction with respect to the installation state of the drive unit 1B on the vehicle, the inverter chamber Se is located above the motor chamber Sa. The breather chamber Sf has a portion that overlaps with the inverter chamber Se when viewed from the direction of the rotation axis X, and overlaps with the motor chamber Sa when viewed from the radial direction of the rotation axis X.

[0166] With this configuration, the breather chamber Sf can be placed in the stepped portion D2 formed by the inverter chamber Se and the motor chamber Sa. This makes it possible to suppress the increase in size of the drive unit 1B.

[0167] (6) A drain pipe 89B (oil return passage) for returning oil OL to the motor chamber Sa is formed in the breather chamber Sf. The breather chamber Sf has a portion that overlaps with the inverter chamber Se when viewed from the direction of the rotation axis X, and overlaps with the motor chamber Sa when viewed from the radial direction of the rotation axis X.

[0168] This configuration allows for a reduction in the size of the drive unit 1B while also shortening the drain pipe 89B.

[0169] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments shown. It can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0170] 1, 1A, 1B: Drive unit, 2: Motor, 3: Power transmission mechanism, 4: First planetary gear, 5: Second planetary gear, 6: Differential mechanism, 7, 7A: Inverter, 8, 8A: Inverter case, 9: Breather (second passage), 71: Circuit board, 72: Capacitor, 73: Input terminal, 74: Output terminal, 81: Bottom wall, 82: Peripheral wall, 83, 83A: Partition wall (bulkhead), 831: First wall, 832: Second wall, 83a, 831a: Through hole (first passage), 85: Cover, 89, 89A, 89B: Drain pipe (oil return passage), 900: Breather passage, D1: Stepped section, D2: Stepped section, OL: Oil, OM: Oil mist, PN: Power supply line PNa: Connector section (external connection terminal), Sa: Motor room (second housing), Sb: Gear room (first housing), Sc, Se: Inverter room (third housing), Sd, Sf: Breather room (fourth housing), VL: Vertical line, X: Rotation axis

Claims

1. A drive unit having a housing that includes a first housing for housing a power transmission mechanism, a second housing for housing a motor, a third housing for housing an inverter, and a fourth housing adjacent to the third housing separated by a partition wall, wherein a breather passage is configured including a first passage provided in the partition wall and a second passage provided in the fourth housing.

2. The drive unit according to claim 1, wherein an external connection terminal for connection to the inverter is provided in the fourth housing chamber.

3. The drive unit according to claim 1, wherein the fourth storage chamber has an oil return passage formed therein for returning oil to the first storage chamber or the second storage chamber.

4. The drive unit according to claim 1, wherein the fourth housing chamber has a portion that overlaps with the third housing chamber in an axial view and overlaps with the first housing chamber or the second housing chamber in a radial view.

5. The drive unit according to claim 1, wherein the fourth housing chamber has an oil return passage formed therein for returning oil to the first housing chamber, and the fourth housing chamber has a portion that overlaps with the third housing chamber in an axial view and overlaps with the first housing chamber in a radial view.

6. The drive unit according to claim 1, wherein the fourth housing chamber has an oil return passage formed therein for returning oil to the second housing chamber, and the fourth housing chamber has a portion that overlaps with the third housing chamber in an axial view and overlaps with the second housing chamber in a radial view.

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