Unit

Abstract

[Problem] To provide a breather structure that has improved resistance to external oil discharge. [Solution] A unit comprises: a breather passage that is configured so as to include a first fin projecting from an inner circumferential surface of a housing, and a second fin projecting toward the inner circumferential surface of the housing; and a cooling part that cools the first fin.

Description

unit

[0001] The present invention relates to a unit.

[0002] Patent Document 1 discloses a breather structure.

[0003] JP 2012-77898 A

[0004] For example, in a unit using a motor as a drive source, when the motor is configured to rotate at high speed, the following tendencies occur: (a) Oil droplets or oil mist are generated due to the agitation of oil caused by the rotation of the rotor shaft and each gear; (b) The generated oil droplets or oil mist tend to have higher thermal energy and kinetic energy as the rotation speed increases. Therefore, in a conventional breather chamber installed in the gear chamber, oil is more likely to spray out. Therefore, there is a demand for a breather structure that is more resistant to oil spraying out.

[0005] In one aspect of the present invention, the unit has a breather passage including a first fin protruding from the inner surface of a housing and a second fin protruding toward the inner surface of the housing, and a cooling section that cools the first fin.

[0006] According to one aspect of the present invention, it is possible to provide a breather structure that has improved resistance to external oil spraying.

[0007] FIG. 1 is a diagram showing a unit. FIG. 2 is a diagram showing a cooling section and a breather passage. FIG. 3 is a diagram showing a breather passage. FIG. 4 is a diagram showing a first fin. FIG. 5 is a diagram showing a second fin. FIG. 6 is a diagram showing a drain section. FIG. 7 is a diagram explaining movement of oil mist in the breather passage. FIG. 8 is a diagram explaining drainage of oil in the breather passage. FIG. 9 is a diagram showing a unit according to a first modification. FIG. 10 is a diagram showing a unit according to a second modification. FIG. 11 is a diagram showing a unit according to the second modification. FIG. 12 is a diagram showing a unit according to the second modification. FIG. 13 is a diagram showing a unit according to the second modification. FIG. 14 is a diagram showing a unit according to a third modification. FIG. 15 is a diagram showing a unit according to the third modification.

[0008] First, definitions of terms used in this specification will be explained. A "unit" is also called a "motor unit," a "power transmission device," etc. A motor unit is a 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 unit that is a device that has a motor and a power transmission mechanism belongs to the concepts of both a motor unit and a power transmission device.

[0009] The "housing" contains the motor, gears, and inverter. The housing is made up of one or more cases.

[0010] The term "motor" refers to a rotating electric machine having a motor function and / or a generator function.

[0011] When it is stated that an element B (component, part, etc.) is connected to an element A (component, part, etc.), an element B (component, part, etc.) is connected downstream of an element A (component, part, etc.), or an element B (component, part, etc.) is connected upstream of an element A (component, part, etc.), it means that the elements A and B are connected so that power can be transmitted. The power input side is the upstream side, and the power output side is the downstream side. Furthermore, the elements A and B may be connected via another element (a clutch, another gear mechanism, etc.).

[0012] "Overlapping when viewed in a predetermined direction" means that multiple elements are lined up in a predetermined direction, and is synonymous with "overlapping in a predetermined direction." The "predetermined direction" is, for example, the axial direction, the radial direction, the direction of gravity, the vehicle traveling direction (the forward direction of the vehicle, the backward direction of the vehicle), etc. When a drawing shows that multiple elements (components, parts, etc.) are lined up in a predetermined direction, it may be assumed that the description in the specification contains a sentence explaining that they overlap when viewed in the predetermined direction.

[0013] "Not overlapping when viewed in a predetermined direction" and "offset when viewed in a predetermined direction" mean that multiple elements are not lined up in a predetermined direction, and are synonymous with "not overlapping in a predetermined direction" and "offset in a predetermined direction." Examples of the "predetermined direction" include the axial direction, radial direction, gravity direction, and vehicle travel direction (vehicle forward direction, vehicle backward direction). When a drawing shows that multiple elements (components, parts, etc.) are not lined up in a predetermined direction, it may be assumed that the description in the specification includes a sentence explaining that they are not overlapping when viewed in a predetermined direction.

[0014] The phrase "element A (component, part, etc.) is located between element B (component, part, etc.) and element C (component, part, etc.) when viewed from a predetermined direction" means that element A can be observed to be located between element B and element C when viewed from a predetermined direction. The "predetermined direction" is, for example, the axial direction, the radial direction, the direction of gravity, the vehicle traveling direction (the forward direction of the vehicle, the backward direction of the vehicle), etc. For example, when element B, element A, and element C are lined up in this order along the axial direction, it can be said that element A is located between element B and element C when viewed from a radial direction. When a drawing shows that element A is located between element B and element C when viewed from a predetermined direction, it can be considered that the description in the specification includes a sentence explaining that element A is located between element B and element C when viewed from the predetermined direction.

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

[0016] "Axial direction" means the axial direction of the rotation axis of the component that constitutes the unit. "Radial direction" means the direction perpendicular to the rotation axis of the component that constitutes the unit. The component is, for example, a motor, a gear mechanism, a differential gear mechanism, etc.

[0017] This embodiment will be described below. In this embodiment, a unit 1 mounted on a vehicle will be described as an example. FIG. 1 is a diagram showing the unit 1. FIG. 1 schematically shows a cross section of the unit 1 along the rotation axis X of the motor 2. In FIG. 1, the power transmission mechanism 3 is shown by an imaginary line. Here, the "vertical direction" in the drawings refers to the vertical direction when the unit 1 is mounted on the vehicle. Therefore, when the term "upper side" is used, it means "upper side" in the vertical direction, and when the term "lower side" is used, it means "lower side" in the vertical direction.

[0018] As shown in FIG. 1, the unit 1 includes a motor 2, a power transmission mechanism 3 that transmits the rotational driving force of the motor 2 to a drive shaft DS, and a housing HS that accommodates the motor 2 and the power transmission mechanism 3.

[0019] The power transmission mechanism 3 may be, for example, a planetary gear mechanism. The power transmission mechanism 3 has a sun gear 31, a pinion gear 32 meshing with the sun gear 31, a carrier 33 supporting the pinion gear 32, and a ring gear 34 meshing with the pinion gear 32.

[0020] The sun gear 31 is provided coaxially with the rotation axis X of the motor 2. The sun gear 31 is connected to the motor shaft 20 of the motor 2 and rotates integrally with the motor 2. The ring gear 34 is fixed to the housing HS so as not to rotate relative to the motor 2. In the power transmission mechanism 3, the sun gear 31 serves as an input part for the output rotation of the motor 2, and the carrier 33 supporting the pinion gear 32 serves as an output part for the input rotation.

[0021] In this embodiment, the rotational driving force of the motor 2 input to the sun gear 31 is decelerated by the revolution of the pinion gear 32 and output from the carrier 33. The rotational driving force output from the carrier 33 is transmitted from the drive shaft DS to the left and right drive wheels (not shown) via a differential mechanism (not shown).

[0022] 1, the housing HS has a motor case 10 that houses the motor 2 and a gear case 14 that houses the power transmission mechanism 3. The motor case 10 and the gear case 14 are joined in the direction of the rotation axis X.

[0023] The motor case 10 includes a case member 11 and a cover member 12 (housing main body) joined to the case member 11 in the direction of the rotation axis X. The case member 11 includes a cylindrical support wall portion 111 that surrounds the rotation axis X. The support wall portion 111 is oriented along the rotation axis X. The motor 2 is housed inside the support wall portion 111. The cover member 12 is connected to one end 111a of the support wall portion 111 with a bolt (not shown). The gear case 14 is connected to the other end 111b of the support wall portion 111 with a bolt (not shown).

[0024] The gear case 14 has a support wall 141 that surrounds the rotation axis X and supports the ring gear 34. The support wall 141 is provided with a wall 140 that extends radially inward between the motor 2 and the power transmission mechanism 3. The wall 140 is provided in a direction perpendicular to the rotation axis X.

[0025] A cylindrical motor support portion 145 is provided in an area of ​​the wall portion 140 that intersects with the rotation axis X. The other end 20b of the motor shaft 20 of the motor 2 passes through the motor support portion 145 in the direction of the rotation axis X. A bearing B1 is supported on the inner periphery of the motor support portion 145. The outer periphery of the motor shaft 20 is supported by the motor support portion 145 via the bearing B1.

[0026] The space formed inside the housing HS is divided into two by a wall 140. The space on the motor 2 side from the wall 140 (on the right side in the figure) is a motor chamber Sa that houses the motor 2. The space on the power transmission mechanism 3 side from the wall 140 (on the left side in the figure) is a gear chamber Sb that houses the power transmission mechanism 3.

[0027] The wall portion 140 is also provided with a through-hole 140a that penetrates in the direction of the rotation axis X. The through-hole 140a is provided below the rotation axis X, between the support wall portion 141 and the motor support portion 145 in the radial direction of the rotation axis X. The motor chamber Sa and the gear chamber Sb are in communication with each other via the through-hole 140a.

[0028] The cover member 12 has a wall portion 120 perpendicular to the rotation axis X and a peripheral wall portion 121 surrounding the outer periphery 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 of the case member 11 on the side of the one end 111a is closed by the cover member 12.

[0029] A cylindrical motor support portion 125 is provided in an area where the wall portion 120 intersects with the rotation axis X. 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 periphery of the motor support portion 125. The outer periphery of the motor shaft 20 is supported by the motor support portion 125 via the bearing B1.

[0030] The motor case 10 also has a lid member 13 joined to the cover member 12. The lid member 13 is provided on the opposite side of the cover member 12 from the case member 11 in the direction of the rotation axis X.

[0031] The cover member 13 has a wall portion 130 that is perpendicular to the rotation axis X. The drive shaft DS penetrates the wall portion 130 in the direction of the rotation axis X through a region that intersects with the rotation axis X. The wall portion 130 is provided with a cylindrical drive shaft support portion 135 that surrounds the drive shaft DS.

[0032] The drive shaft support portion 135 is provided on the surface of the wall portion 130 facing the cover member 12. A bearing B2 is supported on the inner periphery of the drive shaft support portion 135. The outer periphery of the drive shaft DS is supported by the drive shaft support portion 135 via the bearing B2.

[0033] The motor 2 has a cylindrical motor shaft 20, a cylindrical rotor core 21 that is fitted onto the motor shaft 20, a stator core 22 that surrounds the outer periphery of the rotor core 21 at a distance, and coils 23 that are provided on 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.

[0034] Bearings B1, B1 are fitted around the motor shaft 20 on one side and the other side in the direction of the rotation axis X, sandwiching the rotor core 21 therebetween. The motor shaft 20 is rotatably supported by the motor case 10 and the gear case 14 via the bearings B1, B1. A hollow portion 201 extending in the direction of the rotation axis X is provided inside the motor shaft 20. The drive shaft DS passes through the hollow portion 201 of the motor shaft 20. The motor shaft 20 is provided so as to be rotatable relative to the drive shaft DS.

[0035] As shown in Figure 1, the motor chamber Sa stores oil OL that cools the motor 2. The gear chamber Sb stores oil OL that lubricates 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 140a in the wall portion 140. The oil levels of the oil OL in the motor chamber Sa and the gear chamber Sb are aligned via the through-hole 140a.

[0036] The unit 1 according to this embodiment has an oil circulation section P1 that circulates oil OL within the motor chamber Sa and the gear chamber Sb. The oil circulation section P1 has a discharge passage P11 connected to the motor chamber Sa and a supply passage P12 connected to the gear chamber Sb. For example, one end of the discharge passage P11 opens to a region below the motor chamber Sa in the vertical direction, and one end of the supply passage P12 opens to a region above the gear chamber Sb in the vertical direction.

[0037] The other end of the discharge passage P11 (the end opposite the motor chamber Sa) is connected to an oil cooler 51 (cooler). The other end of the supply passage P12 (the end opposite the gear chamber Sb) is connected to the oil cooler 51. The discharge passage P11 and the supply passage P12 are connected via an oil flow path 53 (see FIG. 2) in the oil cooler 51. The oil cooler 51 is provided on the upper surface 121a of the peripheral wall portion 121 of the cover member 12 via a mount portion 50.

[0038] The discharge passage P11 is provided with an oil pump OP and a filter F (see FIG. 1). When the oil pump OP is driven, oil OL stored in the motor chamber Sa is drawn into the discharge passage P11. The oil OL drawn from the motor chamber Sa has a high temperature due to the heat collected from the motor 2.

[0039] The oil OL in the discharge passage P11 is pressurized by the oil pump OP and filtered by the filter F. The pressurized and filtered oil OL is cooled in the oil cooler 51 and then supplied from the supply passage P12 to the gear chamber Sb to lubricate the power transmission mechanism 3. The oil OL in the gear chamber Sb moves from the through-hole 140a in the wall portion 140 toward the motor chamber Sa and cools the motor 2 again.

[0040] Furthermore, the support wall portion 111 of the case member 11 is provided with a flow path 110 through which the refrigerant flows. The flow path 110 is provided so as to surround the outer periphery of the stator core 22. For example, the flow paths 110 are provided with a phase difference in the circumferential direction around the rotation axis X, and are provided in a spiral shape whose position in the direction of the rotation axis X changes from the cover member 12 side toward the gear case 14 side. The refrigerant in the flow path 110 cools the motor 2 together with the oil OL described above. Note that the refrigerant may be a liquid (such as cooling water) or a gas (such as air), which is different from the oil OL. In this embodiment, a case where cooling water W is used as the refrigerant will be described as an example.

[0041] The unit 1 according to this embodiment has a cooling water circulation section P2 that circulates the cooling water W in the flow path 110. The cooling water circulation section P2 has a discharge path P21 and a supply path P22. One end of the discharge path P21 is connected to the flow path 110 on the gear case 14 side. One end of the supply path P22 is connected to the flow path 110 on the cover member 12 side. The other end of the discharge path P21 (the end opposite the flow path 110) is connected to the oil cooler 51. The other end of the supply path P22 (the end opposite the flow path 110) is connected to the oil cooler 51. The discharge path P21 and the supply path P22 are connected via a cooling water flow path 52 (cooling path, see FIG. 2 ) in the oil cooler 51.

[0042] The discharge passage P21 is provided with a radiator RD and a water pump WP (see FIG. 1). When the water pump WP is driven, the coolant W in the flow passage 110 is drawn into the discharge passage P21. The coolant W drawn from the flow passage 110 has recovered heat from the motor 2 and has a high temperature.

[0043] The coolant W in the discharge passage P21 is cooled by the radiator RD and pressurized by the water pump WP. The cooled and pressurized coolant W passes through the oil cooler 51 and is returned from the supply passage P22 to the flow path 110, where it cools the motor 2 again. As the coolant W in the coolant circulation section P2 passes through the oil cooler 51, it cools the oil OL flowing through the oil circulation section P1.

[0044] When the rotor core 21 of the motor 2 and the gears (sun gear 31, pinion gear 32, carrier 33) of the power transmission mechanism 3 rotate, the oil OL in the motor chamber Sa and the gear chamber Sb is stirred up and scattered. In this case, the higher the rotation speed of the motor 2, the more likely the scattered oil OL becomes mist-like. The mist-like scattering of the oil OL can increase the pressure inside the housing HS. The generated oil mist is likely to have higher thermal energy and kinetic energy as the rotation speed increases. Therefore, the housing HS is provided with a breather passage 7 to release the increased pressure. As will be described in detail later, by arranging the breather passage 7 in close proximity to the oil cooler 51, the cooling effect of the oil cooler 51 also acts on the breather passage 7.

[0045] Fig. 2 is a diagram showing the cooling section 5 and the breather passage 7. Fig. 3 is a diagram showing the breather passage 7. Fig. 4 is a diagram showing a first fin 8D. Fig. 4 is a schematic diagram of a cross section taken along line A-A in Fig. 2. Fig. 5 is a diagram showing a second fin 9B. Fig. 5 is a schematic diagram of a cross section taken along line B-B in Fig. 2.

[0046] 2, the cover member 12 has a recess 16 formed by recessing the peripheral wall portion 121 downward. The recess 16 is provided at a connection portion of the peripheral wall portion 121 with the wall portion 120.

[0047] The recess 16 has a bottom wall portion 161 provided below the peripheral wall portion 121 and oriented along the rotation axis X. The bottom wall portion 161 protrudes from a surface 120b of the wall portion 120 of the cover member 12 on the motor chamber Sa side toward the peripheral wall portion 121. The bottom wall portion 161 is located on the inner diameter side of the peripheral wall portion 121 in the radial direction of the rotation axis X.

[0048] When viewed from the vertical direction, a tip 161c side of the bottom wall portion 161 extends to a position where it overlaps with the peripheral wall portion 121. A gap CL1 is provided between an upper surface 161a of the bottom wall portion 161 and a lower surface 121b of the peripheral wall portion 121 in the vertical direction.

[0049] As shown in FIG. 4 , the bottom wall portion 161 of the recess 16 is oriented along a horizontal line HL1. FIG. 4 shows a vertical line VL1 and a horizontal line HL1. The vertical line VL1 is aligned along the extension direction of the first fin 8D and perpendicular to the rotation axis X. The horizontal line HL1 is perpendicular to the vertical line VL1 that passes through the rotation axis X and passes through the intersection of a horizontal hole 171 and a vertical hole 174 of the drain portion 17, which will be described later. Side wall portions 162 and 163 that connect the bottom wall portion 161 and the peripheral wall portion 121 are provided at both ends of the bottom wall portion 161 in the direction of the horizontal line HL1. The side wall portions 162 and 163 are arranged parallel to each other along the vertical line VL1.

[0050] The upper surface 161a of the bottom wall portion 161 is inclined so that its vertical position decreases as it approaches the vertical line VL1 from the connection portion with the side wall portions 162, 163. In other words, the upper surface 161a is inclined so that its vertical position decreases as it moves from both ends in the direction of the horizontal line HL1 toward the center. The upper surface 161a of the bottom wall portion 161 is lowest at an intersection 161a1 with the vertical line VL1 (the center portion in the direction of the horizontal line HL1).

[0051] The internal space of the recess 16, surrounded by the bottom wall 161 and the side wall portions 162 and 163, constitutes the breather chamber Sc. The breather chamber Sc opens to the upper surface 121a of the peripheral wall portion 121. As shown in FIG. 2 , the breather chamber Sc is sandwiched between the peripheral wall portion 121 and the wall portion 120 in the direction of the rotation axis X. The breather chamber Sc communicates with the motor chamber Sa via a gap CL1. Therefore, air from within the motor chamber Sa flows into the breather chamber Sc through the portion where the gap CL1 is formed.

[0052] The oil cooler 51 is attached to the peripheral wall 121 via a mount 50. The mount 50 is plate-shaped and closes the upper opening 16a (opening) of the recess 16. The mount 50 is provided across the upper surface 121a of the peripheral wall 121 and the upper surface 120a of the wall 120. The mount 50 and the oil cooler 51 constitute the cooling section 5 of the unit 1. Note that, although the present embodiment illustrates an example in which the mount 50 and the oil cooler 51 are separate bodies, the mount 50 and the oil cooler 51 may be formed integrally. It is sufficient that heat can be exchanged between the mount 50 and the oil cooler 51.

[0053] 5, the mount 50 of the cooling unit 5 is fixed to the upper surface 121a of the peripheral wall 121 by a bolt B. A seal material S seals the gap between the mount 50 and the upper surface 121a of the peripheral wall 121.

[0054] 2, the oil cooler 51 of the cooling unit 5 has a housing 511 with a bottom and an opening facing downward. The lower opening of the housing 511 is sealed by the upper surface 501 of the mount unit 50. The discharge path P21 and the supply path P22 of the cooling water circulation unit P2 are connected to the housing 511. The internal space of the housing 511 forms a cooling water flow path 52 through which the cooling water W flows.

[0055] An oil flow path 53 through which oil OL flows is arranged in the cooling water flow path 52 of the housing 511. The oil flow path 53 has an inlet pipe 531, an outlet pipe 532, and a heat radiation pipe 533 that connects the inlet pipe 531 and the outlet pipe 532.

[0056] The inlet pipe 531 passes through the housing 511 and is connected to the discharge path P11 of the oil circulation section P1 outside the housing 511. The discharge pipe 532 passes through the housing 511 and is connected to the supply path P12 of the oil circulation section P1 outside the housing 511. A plurality of heat radiation pipes 533 are provided between the inlet pipe 531 and the discharge pipe 532.

[0057] In the oil cooler 51, the oil OL flows from the discharge passage P11 of the oil circulation section P1 into the inlet pipe 531 of the oil flow passage 53. The oil OL that has flowed into the inlet pipe 531 is cooled by heat exchange with the cooling water W in the cooling water flow passage 52 as it passes through the heat radiation pipe 533. The oil OL that has been cooled after passing through the heat radiation pipe 533 is discharged from the discharge pipe 532 to the supply passage P12 of the oil circulation section P1.

[0058] 2, the cooling unit 5 closes the upper opening 16a of the recess 16 on the bottom surface 502 side of the mount unit 50 in the up-down direction. Therefore, the bottom surface 502 of the mount unit 50 forms part of the inner circumferential surface of the housing HS.

[0059] Furthermore, a breather 6 for releasing the air in the breather chamber Sc to the atmosphere is provided in the mount part 50 of the cooling part 5. The mount part 50 is formed with a breather hole 55 that opens to a lower surface 502 and a side surface 503. The side surface 503 connects the upper surface 501 and the lower surface 502 of the mount part 50.

[0060] 3 , the breather 6 has a breather pipe 61 inserted into the breather hole 55 from the side surface 503, and a filter 60 that closes the opening of the breather pipe 61. The breather chamber Sc communicates with the outside via the breather hole 55 and the breather 6. Note that the breather 6 may not be provided with the breather pipe 61. For example, the filter 60 may be provided directly in the breather hole 55 of the mount portion 50.

[0061] The housing HS is formed with a breather passage 7 that is made up of a breather chamber Sc, a breather hole 55, and a breather 6. An area in the breather chamber Sc that opens to the tip 161c of the bottom wall portion 161 forms an inlet portion 7a of the breather passage 7. Air within the motor chamber Sa flows into the breather passage 7 from the inlet portion 7a, and finally enters the breather hole 55 and is released to the atmosphere through the breather 6.

[0062] As shown in Figure 2, the rising oil mist OM and oil droplets tend to collect on the upper side of the motor chamber Sa (the cross-hatched area in Figure 2). The oil mist OM and oil droplets are mist-like oil OL that is stirred up and scattered inside the housing HS by the rotation of the rotor core 21 and the power transmission mechanism 3 (see Figure 1).

[0063] For example, the higher the rotation speed of the motor 2, the more the stirred-up oil OL scatters, and the kinetic energy of the oil mist OM and oil droplets tends to increase. Also, the higher the rotation speed of the motor 2, the greater the heat generated by the motor 2, and the greater the thermal energy of the oil mist OM and oil droplets tends to increase. In the following explanation, oil mist OM and oil droplets will be collectively referred to simply as "oil mist OM."

[0064] The greater the kinetic energy and thermal energy of the oil mist OM, the greater its fluidity. Therefore, when the air in the motor chamber Sa is released to the atmosphere, a large amount of oil mist OM tends to enter the breather passage 7. This makes it easier for the oil mist OM to pass through the breather passage 7 and be ejected to the outside from the breather 6. Therefore, in this embodiment, a labyrinth portion 75 is provided in the breather chamber Sc to restrict the movement of the oil mist OM toward the breather 6.

[0065] The labyrinth portion 75 is composed of thin plate-shaped first fins 8 provided on the mount portion 50 of the cooling unit 5 and thin plate-shaped second fins 9 provided in the recess 16. The first fins 8 protrude from the lower surface 502 of the mount portion 50 (the inner peripheral surface of the housing HS) toward the upper surface 161 a of the bottom wall portion 161 located below. In other words, the mount portion 50 constitutes a support portion that supports the first fins 8. The second fins 9 protrude from the upper surface 161 a of the bottom wall portion 161 of the recess 16 toward the lower surface 502 of the mount portion 50 located above (the inner peripheral surface of the housing HS). The first fins 8 and the second fins 9 are alternately arranged in the direction of the rotation axis X to constitute the labyrinth portion 75.

[0066] 3, in this embodiment, four first fins 8 (8A to 8D) are provided on the mount portion 50. The first fins 8 (8A to 8D) are formed integrally with the mount portion 50. Note that the first fins 8 and the mount portion 50 may be formed separately. It is sufficient that heat can be transferred between the first fins 8 and the mount portion 50.

[0067] When viewed from the vertical direction, which is the protruding direction of the first fins 8, the first fins 8 (8A to 8D) are provided in a position where they overlap (overlap) the oil cooler 51 and the cooling water flow passage 52 of the oil cooler 51.

[0068] The mount 50 and the first fins 8 are made of a material with high thermal conductivity, such as copper or aluminum, so that the first fins 8 are cooled by the cooling water W (see FIG. 2 ) in the cooling water flow passage 52 via the mount 50.

[0069] The four first fins 8 (8A to 8D) have the same shape and are spaced apart in the direction of the rotation axis X. A gap CL2 is provided between the tip surface 81 of each first fin 8 (8A to 8D) in the vertical direction and the upper surface 161 a of the bottom wall portion 161 of the recess 16.

[0070] 3, in this embodiment, three second fins 9 (9A to 9C) are provided on the bottom wall portion 161 of the recess 16. The three second fins 9 (9A to 9C) have the same shape and are provided at intervals in the direction of the rotation axis X.

[0071] A gap CL3 is provided between the tip surfaces 91 of the second fins 9 (9A to 9C) in the vertical direction and the lower surface 502 of the mount part 50 of the cooling unit 5. The tip surfaces 91 of the second fins 9 (9A to 9C) are located above the tip surfaces 81 of the first fins 8. When viewed from the direction of the rotation axis X, the first fins 8 (8A to 8D) and the second fins 9 (9A to 9C) have overlapping portions.

[0072] The first fins 8 and the second fins 9 are alternately arranged at a distance CL4 in the direction of the rotation axis X. Specifically, the second fin 9A is located between the first fins 8A and 8B arranged in the direction of the rotation axis X. The second fin 9B is located between the first fins 8B and 8C arranged in the direction of the rotation axis X. The second fin 9C is located between the first fins 8C and 8D arranged in the direction of the rotation axis X. The first fin 8B has a region sandwiched between the two second fins 9A and 9B (a pair of second fins 9). The first fin 8C has a region sandwiched between the two second fins 9B and 9C (a pair of second fins 9). The number of first fins 8 and second fins 9 is not particularly limited. When at least one first fin 8 has a region sandwiched between two second fins 9 (a pair of second fins 9), a labyrinth portion 75 can be formed.

[0073] 4, the first fin 8D has a generally rectangular shape when viewed from the direction of the rotation axis X and extends in a direction along a horizontal line HL1. One side surface 82 and the other side surface 83 of the first fin 8D in the direction of the horizontal line HL1 abut against the inner wall surfaces 162a, 163a of the side wall portions 162, 163 of the recess 16 without any gap. Therefore, in the region of the breather chamber Sc where the first fin 8D is provided, the portion other than the lower gap CL2 is sealed.

[0074] Here, the upper surface 161a of the bottom wall portion 161 slopes downward from the connection portion with the side wall portions 162, 163 toward the intersection 161a1 with the vertical line VL1. Therefore, the gap CL2 between the tip surface 81 of the first fin 8D and the upper surface 161a of the bottom wall portion 161 is widest in the region through which the vertical line VL1 passes (the center in the direction of the horizontal line HL1). Note that although FIG. 4 illustrates the shape of the first fin 8D as a representative of the first fins 8, the other first fins 8A to 8C (see FIG. 3) also have a shape similar to that of the first fin 8D.

[0075] 5, the second fin 9B has a generally rectangular shape when viewed from the direction of the rotation axis X and extends in a direction along a horizontal line HL2. The horizontal line HL2 is perpendicular to a vertical line VL2 passing through the rotation axis X and intersects with a horizontal hole 171 of the drain portion 17 (described later). The second fin 9B is provided across an upper surface 161a of the bottom wall portion 161 of the recess 16 and inner wall surfaces 162a, 163a of the side wall portions 162, 163. Therefore, in the region of the breather chamber Sc where the second fin 9B is provided, the entire region except for the upper gap CL3 is sealed.

[0076] 3, the gaps CL2 and CL3 are provided at positions offset in the vertical direction and alternately provided in the direction of the rotation axis X. Therefore, when the oil mist OM in the breather passage 7 passes between the first fin 8 and the second fin 9, it is guided to pass through the gaps CL2 and CL3 while repeatedly moving in the vertical direction. As a result, the first fin 8 and the second fin 9 function as a labyrinth in the breather chamber Sc that restricts the oil mist OM from moving linearly toward the breather 6.

[0077] As shown in FIG. 3 , a drain portion 17 that discharges oil OL from the breather chamber Sc is formed in the bottom wall portion 161 of the recess 16. The drain portion 17 has vertical holes 172, 173, and 174 that are oriented in the up-down direction in the bottom wall portion 161. The drain portion 17 also has a horizontal hole 171 that is oriented in the direction of the rotation axis X, which intersects the up-down direction, below the vertical holes 172, 173, and 174. The drain portion 17 also has a vertical hole 175 that is oriented in the up-down direction below the horizontal hole 171. The vertical holes 172, 173, and 174 discharge the oil OL from the breather chamber Sc to the horizontal hole 171. The horizontal hole 171 guides the discharged oil OL to the vertical hole 175. The vertical hole 175 discharges the oil OL introduced from the horizontal hole 171 into the motor chamber Sa.

[0078] The horizontal hole 171 of the drain portion 17 is a blind hole provided in a direction along the rotation axis X. One end 171a of the horizontal hole 171 in the direction of the rotation axis X opens to a surface 120c of the wall portion 120 opposite the motor chamber Sa and is sealed with a plug PG. The other end 171b of the horizontal hole 171 extends to the region between the second fins 9A and 9B in the direction of the rotation axis X.

[0079] Fig. 6 is a diagram showing the drain portion 17. Fig. 6 is an enlarged view of region C in Fig. 2. As shown in Fig. 6, the upper end 172a of the vertical hole 172 opens to the upper surface 161a of the bottom wall portion 161 between the second fins 9A and 9B in the direction of the rotation axis X. The upper end 172a of the vertical hole 172 faces the tip surface 81 of the first fin 8B in the vertical direction with a gap CL2 (see Fig. 4) between them. The lower end 172b of the vertical hole 172 communicates with the horizontal hole 171.

[0080] An upper end 173a of the vertical hole 173 opens to an upper surface 161a of the bottom wall portion 161 between the second fins 9B and 9C in the direction of the rotation axis X. The upper end 173a of the vertical hole 173 faces the tip surface 81 of the first fin 8C in the vertical direction with a gap CL2 (see FIG. 4 ) therebetween. A lower end 173b of the vertical hole 173 communicates with the horizontal hole 171.

[0081] An upper end 174a of the vertical hole 174 opens to an upper surface 161a of the bottom wall portion 161 between the second fin 9C and the wall portion 120 in the direction of the rotation axis X. The upper end 174a of the vertical hole 174 faces the tip surface 81 of the first fin 8D in the vertical direction with a gap CL2 therebetween. A lower end 174b of the vertical hole 174 communicates with the horizontal hole 171.

[0082] An upper end 175a of the vertical hole 175 communicates with the horizontal hole 171. A lower end 175b of the vertical hole 175 opens to the lower surface 161b of the bottom wall portion 161. The vertical hole 175 is provided in a position that overlaps with the vertical hole 174 when viewed from the top-bottom direction. In other words, the vertical holes 174 and 175 can also be regarded as a single through-hole that passes through the bottom wall portion 161 in the top-bottom direction and intersects with the horizontal hole 171.

[0083] As shown in Fig. 4, when viewed from the direction of the rotation axis X, the vertical hole 174 of the drain portion 17 is provided at a position that overlaps with an intersection 161a1 of the bottom wall portion 161 with the vertical line VL1. In other words, the vertical hole 174 is provided at a position where the height is lowest (the center in the direction of the horizontal line HL1) on the upper surface 161a of the bottom wall portion 161. Although not shown, the vertical holes 172 and 173 (see Fig. 6) are also similarly provided at a position where the height is lowest (the center in the direction of the horizontal line HL1) on the upper surface 161a of the bottom wall portion 161 when viewed from the direction of the rotation axis X.

[0084] Fig. 7 is a diagram illustrating the movement of oil mist OM in the breather passage 7. Fig. 8 is a diagram illustrating the drainage of oil OL in the breather passage 7. Fig. 8 is a schematic diagram of the A-A cross section in Fig. 7. Note that in Fig. 8, the positions of the first fins 8 (8A to 8D) are indicated by virtual lines.

[0085] The breather passage 7 is provided in an upper portion of the motor chamber Sa. The breather passage 7 is provided along the rotation axis X. When viewed from the direction of the rotation axis X, the upper region of the breather passage 7 overlaps with the peripheral wall portion 121 of the cover member 12. The inlet portion 7a of the breather passage 7 is provided in a lower region that does not overlap with the peripheral wall portion 121. The opening area of ​​the inlet portion 7a is sufficiently narrow compared to the flow path cross-sectional area of ​​the breather passage 7. The opening of the inlet portion 7a faces in a direction along the lower surface 121b of the peripheral wall portion 121 (the left-right direction in FIG. 7 ). By arranging the inlet portion 7a in this manner, oil OL or oil mist OM scooped up by the rotation of the motor 2 is less likely to enter the breather passage 7 while retaining the kinetic energy it retained when it was scooped up.

[0086] When viewed from the direction of the rotation axis X, the wall portion 120 of the cover member 12 overlaps with the breather passage 7. The opening of the breather passage 7 opposite the inlet portion 7a is closed by the wall portion 120. In this embodiment, a breather hole 55 that connects the inside of the breather passage 7 with the outside of the housing HS is provided in the mount portion 50 that closes the upper opening 16a of the recess 16. The breather hole 55 is provided at a position separated in the direction of the rotation axis X from the inlet portion 7a that opens at the tip 161c of the bottom wall portion 161. Specifically, the breather hole 55 opens at an upper portion of the breather passage 7 on the wall portion 120 side. The breather hole 55 extends upward along the wall portion 120 and then bends toward the wall portion 120. The tip of the breather hole 55 opens to a side surface 503 of the mount portion 50 above the wall portion 120. In other words, the breather hole 55 is provided downstream of the flow of the oil mist OM in the breather passage 7 .

[0087] By arranging the breather hole 55 in this manner, oil mist OM that has entered the breather passage 7 from the inlet portion 7a moves vertically within the breather passage 7 and cannot reach the breather hole 55 until it collides with the wall portion 120 and changes its direction of movement. Furthermore, because the breather hole 55 is curved, it is difficult for the oil mist OM that has entered the breather hole 55 to reach the breather 6 on the tip side of the breather hole 55.

[0088] As shown in Figure 7, air within the motor chamber Sa flows into the breather passage 7 through the inlet 7a and is released to the atmosphere through the breather 6. This causes an air flow toward the breather 6 within the motor chamber Sa. Oil mist OM within the motor chamber Sa is carried by this air flow and enters the breather passage 7 from the inlet 7a (indicated by the cross-hatched arrows in the figure). Therefore, the air flowing through the breather passage 7 contains oil mist OM.

[0089] The oil mist OM that enters the breather passage 7 from the inlet 7a reaches the labyrinth portion 75. Within the labyrinth portion 75, some of the oil mist OM collides with the first fins 8A and is restricted in its movement (arrow a in the figure). On the other hand, the oil mist OM that does not collide with the first fins 8A moves in the direction of the rotation axis X between the first fins 8A and the bottom wall portion 161 in the vertical direction (arrow b in the figure).

[0090] The oil mist OM that passes between the first fin 8A and the bottom wall portion 161 rises between the first fin 8A and the second fin 9A, then turns back between the second fin 9A and the mount portion 50, and descends between the second fin 9A and the first fin 8B (arrow c in the figure).

[0091] The oil mist OM that descends between the second fin 9A and the first fin 8B then moves toward the wall portion 120 in the direction of the rotation axis X, repeatedly moving up and down between the first fins 8B to 8D and the second fins 9B to 9C. During this movement, the oil mist OM moves inside the breather chamber Sc while colliding with the first fin 8 and the second fin 9, thereby reducing its kinetic energy. This makes it difficult for the oil mist OM that has entered the breather chamber Sc from the inlet portion 7a to reach the breather hole 55.

[0092] Furthermore, in this embodiment, the mount 50 and first fins 8 of the cooling unit 5 are cooled by the cooling water W in the cooling water flow path 52. Therefore, when the oil mist OM comes into contact with the lower surface 502 of the mount 50 and the first fins 8, the heat H of the oil mist OM is transferred to the cooling water flow path 52 and is collected by the cooling water W (indicated by the thick arrow in the figure). This cools the oil mist OM in the breather passage 7, reducing its thermal energy.

[0093] The cooled oil mist OM liquefies to become oil OL. The liquefied oil OL falls by its own weight along the first fins 8 and drips from the tip end surface 81 (see FIG. 6). The oil OL dripping from the tip end surface 81 is stored in the breather chamber Sc.

[0094] In this embodiment, one first fin 8 (for example, the first fin 8B) is sandwiched between two second fins 9 (for example, the second fins 9A and 9B), so that the oil mist OM comes into contact with both surfaces of the first fin 8 in the direction of the rotation axis X. This increases the contact area between the oil mist OM and the first fins 8, making it possible to cool the oil mist OM more efficiently.

[0095] In this way, even if oil mist OM is contained in the air Air flowing through the breather passage 7, the kinetic energy and thermal energy of the oil mist OM are significantly reduced as it passes between the first fin 8 and the second fin 9. Therefore, the oil mist OM that has entered the breather passage 7 loses a significant amount of fluidity in the breather chamber Sc, making it difficult for it to reach the breather hole 55.

[0096] As a result, oil mist OM is removed from the air flowing through the breather passage 7 as it passes between the first fin 8 and the second fin 9. This allows air with less oil content to move from the breather hole 55 to the breather 6. Therefore, it is possible to provide a breather structure in the unit 1 that is more resistant to the external ejection of oil OL.

[0097] In this embodiment, the breather hole 55 is formed in the mount portion 50. Therefore, even if oil mist OM enters the breather hole 55, the oil mist OM is cooled within the breather hole 55. After being cooled and liquefied within the breather hole 55, the oil mist OM falls under its own weight and is returned to the breather chamber Sc.

[0098] Here, for example, it is conceivable to cool the first fins 8 using a cooler separate from the oil cooler 51. However, using a cooler separate from the oil cooler 51 leads to increased costs. Therefore, in this embodiment, the first fins 8 are cooled using the oil cooler 51 that is already provided in the unit 1. This eliminates the need to provide a separate, dedicated cooler for cooling the first fins 8, which contributes to cost reduction.

[0099] It is also conceivable to form the first fins 8 and the mount portions 50 that support the first fins 8 integrally with the cover member 12. However, because the cover member 12 is formed by casting or the like, it is difficult to form the first fins 8 and the mount portions 50, which have a somewhat complex structure, integrally with the cover member 12. Therefore, in this embodiment, the first fins 8 and the mount portions 50 are formed separately from the cover member 12, making it easier to form the cover member 12 by casting or the like. Furthermore, by forming the first fins 8 and the mount portions 50 separately from the cover member 12, it is also possible to insert and attach an assembly of the first fins 8, the mount portions 50, and the oil cooler 51 into the cover member 12. This also contributes to improved ease of attachment.

[0100] 7, the oil OL cooled and liquefied by the first fin 8A is returned to the motor chamber Sa from the inlet 7a due to its own weight. The oil OL cooled and liquefied by the first fin 8B is stored between the second fins 9A and 9B in the breather chamber Sc. The oil OL cooled and liquefied by the first fin 8C is stored between the second fins 9B and 9C in the breather chamber Sc. The oil OL cooled and liquefied by the first fin 8D is stored between the second fin 9C and the wall 120 in the breather chamber Sc.

[0101] If an excessive amount of liquefied oil OL accumulates in the breather chamber Sc, the possibility of the oil OL spraying out increases. Therefore, in this embodiment, a drain portion 17 is provided for draining the oil OL stored in the breather chamber Sc. The drain portion 17 has vertical holes 172, 173, and 174. The vertical hole 172 opens between the second fins 9A and 9B on the upper surface 161 a of the bottom wall portion 161 of the recess 16, the vertical hole 173 opens between the second fins 9B and 9C, and the vertical hole 174 opens between the second fin 9C and the wall portion 120.

[0102] The vertical holes 172, 173, and 174 communicate with the vertical hole 175 via the horizontal hole 171. The vertical hole 175 opens into the motor chamber Sa. Therefore, the oil OL that has accumulated in the breather chamber Sc between the second fins 9A and 9B, between the second fins 9B and 9C, and between the second fin 9C and the wall portion 120 is discharged from the breather chamber Sc to the motor chamber Sa by the drain portion 17. This prevents the oil OL from accumulating in the breather chamber Sc, thereby contributing to improving resistance to the oil OL being sprayed out.

[0103] 6, in this embodiment, the vertical holes 172, 173, and 174 of the drain portion 17 are provided at positions that face the tip surfaces 81 of the first fins 8B to 8D in the up-down direction, respectively. This allows droplets of oil OL dripping from the tip surfaces 81 of the first fins 8 to directly fall into the vertical holes 172, 173, and 174, thereby improving the efficiency of draining the oil OL.

[0104] 4, the upper surface 161a of the bottom wall portion 161 slopes downward from the connection portion with the side wall portions 162, 163 toward the intersection 161a1 with the vertical line VL1. Also, as shown in FIG. 8, the vertical hole 174 is provided at a position overlapping with the intersection 161a1 in the bottom wall portion 161. The vertical holes 172, 173 are similarly positioned.

[0105] Therefore, as shown in Fig. 8 , even if droplets of oil OL dripping from the tip surface 81 of the first fin 8 land at a position offset from the vertical holes 172, 173, and 174, they are guided to the vertical holes 172, 173, and 174 along the slope of the upper surface 161a of the bottom wall portion 161 (in the direction of the arrows in Fig. 8 ). This allows the oil OL stored in the breather chamber Sc to be quickly drained. Note that although the upper surface 161a of the bottom wall portion 161 may be a flat surface perpendicular to the vertical line VL1, an inclined surface as in this embodiment is advantageous in that the oil OL can be quickly guided to the vertical holes 172, 173, and 174.

[0106] 7, the vertical hole 174 is positioned so as to overlap the vertical hole 175 in the up-down direction, and together with the vertical hole 175, they form a single through-hole that passes through the bottom wall portion 161 in the up-down direction. Therefore, the oil OL drained from the vertical hole 174 flows directly into the vertical hole 175 without passing through the horizontal hole 171 and is then discharged into the motor chamber Sa. On the other hand, the oil OL drained from the vertical holes 172 and 173 passes through the horizontal hole 171, joins the vertical hole 175, and is then released from the lower surface 161b of the bottom wall portion 161 and returned to the motor chamber Sa.

[0107] It is possible to configure all of the vertical holes 172, 173, and 174 of the drain portion 17 as through-holes that vertically penetrate the bottom wall portion 161. In this case, the horizontal hole 171 can be omitted. However, there is a possibility that the oil mist OM and the stirred-up oil OL in the motor chamber Sa may flow back through these through-holes and easily invade the breather chamber Sc. Therefore, in this embodiment, only the vertical holes 174 and 175 are configured as through-holes, and the other vertical holes 172 and 173 are connected to the vertical hole 175 via the horizontal hole 171. By reducing the number of through-holes that directly connect the motor chamber Sa and the breather chamber Sc, the oil mist OM and the stirred-up oil OL are prevented from flowing back through the drain portion 17 and invading the breather chamber Sc.

[0108] In the motor chamber Sa, the area farther from the motor 2 in the direction of the rotation axis X is less affected by the oil OL being scooped up, resulting in less fluctuation in the oil level of the oil OL stored in the motor chamber Sa. In other words, the oil mist OM and the scooped-up oil OL are less likely to reach the areas of the motor chamber Sa farther from the motor 2 in the direction of the rotation axis X. Therefore, in this embodiment, through-holes (vertical holes 174, 175) that directly connect the breather chamber Sc to the motor chamber Sa are formed in the motor chamber Sa at the location farthest from the motor 2. The other vertical holes 172, 173 are configured to communicate with the vertical hole 175 via the horizontal hole 171. This makes it more difficult for the oil mist OM and the scooped-up oil OL to enter the breather chamber Sc.

[0109] In this embodiment, as shown in FIG. 6 , the vertical holes 174, 175 of the drain portion 17 form through holes, but this is not limiting. For example, the vertical hole 175 may be offset from the vertical hole 174 when viewed from the top-bottom direction. For example, the vertical hole 175 may be positioned closer to the wall portion 120 than the vertical hole 174 when viewed from the top-bottom direction. In this case, the oil OL discharged into the vertical hole 174 is introduced into the vertical hole 175 via the horizontal hole 171, similar to the vertical holes 172, 173. With this configuration, even if the oil mist OM and the oil OL scooped up in the motor chamber Sa flow back through the vertical hole 175, they collide with the inner wall of the horizontal hole 171 before entering the vertical hole 174. This prevents the oil mist OM and oil OL from flowing back into the motor chamber Sa, making it more difficult for them to enter the breather chamber Sc.

[0110] Examples of the unit 1 according to certain aspects of the present invention are listed below. (1) The unit 1 has a breather passage 7 and a cooling unit 5. A lower surface 502 of a mount portion 50 of the cooling unit 5 forms the inner peripheral surface of the housing HS. The breather passage 7 includes a first fin 8 protruding from the lower surface 502 of the mount portion 50 and a second fin 9 protruding toward the lower surface 502 of the mount portion 50. The cooling unit 5 cools the first fin 8.

[0111] With this configuration, oil mist OM passing through the breather passage 7 is more likely to collide with the first fins 8 and the second fins 9. This makes it possible to reduce the kinetic energy of the oil mist OM within the breather passage 7. Furthermore, by cooling the first fins 8 with the cooling section 5, it is possible to reduce the thermal energy of the oil mist OM. Due to this reduction in kinetic energy and thermal energy, the oil mist OM becomes liquefied and more likely to drip, making it possible to provide a breather structure that is more resistant to the external spraying of oil OL.

[0112] (2) The cooling unit 5 includes an oil cooler 51, which is a heat exchanger provided separately from the housing HS. The oil cooler 51 exchanges heat between the oil OL in the housing HS and the cooling water W, which is a coolant separate from the oil OL.

[0113] With this configuration, the first fins 8 can be cooled by effectively utilizing the oil cooler 51 that is already provided in the unit 1. This eliminates the need to provide a separate cooler specifically for cooling the first fins 8, which contributes to reducing the size of the unit 1. It also contributes to reducing the cost of the unit 1.

[0114] (3) When viewed in the vertical direction of the unit 1 along the protruding direction of the first fins 8 (viewed in a predetermined direction), the oil cooler 51 has a portion that overlaps (is superimposed on) the first fins 8 .

[0115] With this configuration, the oil cooler 51 can be disposed near the first fins 8 of the unit 1, thereby improving the heat exchange efficiency between the oil cooler 51 and the first fins 8. The direction in which the oil cooler 51 overlaps with the first fins 8 is not limited to when viewed from the top-bottom direction. For example, the first fins 8 and the second fins 9 can be disposed side by side in the top-bottom direction so that they each protrude in the direction of the rotation axis X. In this case, the oil cooler 51 is disposed to the side of the first fins 8. The oil cooler 51 has a portion that overlaps with the first fins 8 when viewed from the direction of the rotation axis X. In other words, "viewed from a predetermined direction" corresponds to the protruding direction of the fins (axial, radial, or other direction).

[0116] (4) The cooling unit 5 is provided in the housing HS and has a cooling water flow path 52 (cooling passage) through which the cooling water W flows.

[0117] The cooling section 5 can cool the first fins 8 by effectively utilizing the cooling water W used in the oil cooler 51. This eliminates the need to provide a separate cooler specifically for cooling the first fins 8, which can contribute to reducing the size of the unit 1. It can also contribute to reducing the cost of the unit 1.

[0118] (5) When viewed in the vertical direction along the protruding direction of the first fins 8 (viewed in the predetermined direction), the cooling water flow passages 52 have portions that overlap with the first fins 8 .

[0119] With this configuration, the cooling water flow passage 52 can be disposed near the first fins 8, thereby improving the efficiency of heat exchange between the cooling water W and the first fins 8.

[0120] (6) The housing HS includes the cover member 12 (housing main body) and a mount 50 (support portion) of the cooling unit 5 that supports the first fins 8. The mount 50 is inserted into the upper opening 16 a (opening) of the recess 16 of the cover member 12.

[0121] The set of the first fins 8 and the mount 50 has a somewhat complicated structure. By forming the mount 50 separately from the cover member 12 of the housing HS, it becomes easier to form the cover member 12 by casting or the like. It is also possible to mount the first fins 8, mount 50, and oil cooler 51 as an assembly by inserting it into the cover member 12. This is preferable because it facilitates attachment to the housing HS.

[0122] (Modification 1) In the above embodiment, the breather passage 7 is connected to the motor chamber Sa, but the present invention is not limited to this. For example, in the unit 1A including the inverter case 4, the breather passage 7 may be provided in the inverter chamber Sd.

[0123] 9 is a diagram showing a unit 1A according to Modification 1. In the following description, the same components as those in the embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0124] As shown in Fig. 9, the unit 1A according to the first modification has an inverter INV, which is a power conversion device for the motor 2. The housing HS has an inverter case 4 that houses the inverter INV. The inverter case 4 is provided above the motor 2, straddling a case member 11 and a cover member 12. The inverter case 4 is provided at the highest position in the housing HS.

[0125] The inverter case 4 has a bottom wall 40 joined to the upper surface 111c of the support wall 111 of the case member 11, and a bottomed housing 41 with an opening facing downward. The lower opening of the housing 41 is sealed by the bottom wall 40. In the inverter case 4, the space surrounded by the bottom wall 40 and the housing 41 forms an inverter chamber Sd that houses the inverter INV.

[0126] The housing 41 of the inverter case 4 has a ceiling wall 410 that faces the bottom wall 40 in the vertical direction with a gap therebetween, and a peripheral wall 411 that surrounds the outer periphery of the ceiling wall 410. A lower end surface 411a of the peripheral wall 411 abuts against the bottom wall 40 along the entire periphery.

[0127] The bottom wall 40 of the inverter case 4 is provided with a through-hole 40a that penetrates in the vertical direction and a cylindrical wall 45 that surrounds the through-hole 40a. The cylindrical wall 45 is provided across the one end 111a of the support wall 111 in the vertical direction. A lower end surface 45a of the cylindrical wall 45 is joined to an upper surface 121c of the peripheral wall 121 of the cover member 12.

[0128] A through-hole 126 that connects the inside and outside of the motor chamber Sa is formed in the upper surface 121c of the peripheral wall portion 121 of the cover member 12. When viewed from the top and bottom, the through-hole 126 is formed in a position that overlaps with the through-hole 40a of the inverter case 4. As a result, the motor chamber Sa is in communication with the inverter chamber Sd via the through-holes 126 and 40a.

[0129] The inverter INV and the coil 23 of the motor 2 are electrically connected via a bus bar Bs. The bus bar Bs passes through the through hole 40a of the inverter case 4 and the through hole 126 of the cover member 12, and is provided across the motor chamber Sa and the inverter chamber Sd.

[0130] As indicated by the cross-hatched arrows in the figure, oil mist OM generated by the rotation of the motor 2 rises from the motor chamber Sa through the through-holes 126 and 40a and enters the inverter chamber Sd. The oil mist OM that enters the inverter chamber Sd gathers around the top wall 410 located at the top. Therefore, in the unit 1A according to the first modification, a breather passage 7 is provided in the housing portion 41 of the inverter case 4. Specifically, a recess 16A is provided by recessing the top wall 410 of the housing portion 41 downward, and the upper opening 16a of the recess 16A is blocked by the mount portion 50 of the cooling unit 5, thereby forming the breather passage 7. An oil cooler 51 is provided above the mount portion 50.

[0131] As in the embodiment, the oil mist OM that has entered the breather passage 7 from the inverter chamber Sd passes between the first fin 8 and the second fin 9, whereby its kinetic energy and thermal energy are greatly reduced. As a result, the fluidity of the oil mist OM is greatly reduced, and the oil mist OM is liquefied and stored in the breather chamber Sc. The oil OL that has liquefied in the breather chamber Sc is discharged from the drain portion 17 provided in the bottom wall portion 161 and returned to the motor chamber Sa through the through holes 126 and 40a.

[0132] In this way, even in the unit 1A having the inverter chamber Sd, oil mist OM is removed from the air Air flowing through the breather passage 7, and air with less oil content Air moves from the breather hole 55 to the breather 6. Therefore, in the unit 1A according to the first modification, it is possible to provide a breather structure with improved resistance to the external spraying of oil OL.

[0133] (Variation 2) In the above-described embodiment, as one aspect of the breather passage 7 (see FIG. 3 ), an example is shown in which the first fin 8 and the second fin 9 face the bottom wall 161 of the recess 16 and the mount 50 with gaps CL2 and CL3 in the up-down direction, respectively. However, the breather passage is not limited to this aspect. For example, in Variation 2, a breather passage 7A will be described in which the first fin 8 and the second fin 9 are provided with no gaps in the up-down direction with respect to the bottom wall 161 of the recess 16 and the mount 50, respectively.

[0134] FIG. 10 is a diagram showing a unit 1B according to Modification 2. FIG. 11 is a diagram showing a unit 1B according to Modification 2. FIG. 11 is a schematic diagram of the A-A cross section of FIG. 10. FIG. 12 is a diagram showing a unit 1B according to Modification 2. FIG. 12 is a schematic diagram of the B-B cross section of FIG. 10. FIG. 13 is a diagram showing a unit 1B according to Modification 2. FIG. 13 is a schematic diagram of the C-C cross section of FIG. 10.

[0135] 10 , in the breather passage 7A of the unit 1B according to the second modification, the first fins 8 (8E to 8H) extend downward from the lower surface 502 of the mount portion 50, and the tip surfaces 85 abut against the upper surface 161 a of the bottom wall portion 161 of the recess 16B. The second fins 9 (9D to 9F) extend upward from the upper surface 161 a of the bottom wall portion 161 of the recess 16B, and the tip surfaces 95 abut against the lower surface 502 of the mount portion 50.

[0136] 12 , when viewed from the direction of the rotation axis X, the first fin 8H has a generally rectangular shape and extends in a direction along a horizontal line HL1. A gap CL5 is provided between one side surface 86 of the first fin 8H in the direction of the horizontal line HL1 and the inner wall surface 162a of the side wall portion 162 of the recess 16B. The other side surface 87 of the first fin 8H in the direction of the horizontal line HL1 abuts against the inner wall surface 163a of the side wall portion 163 of the recess 16B. A tip surface 85 of the first fin 8H abuts against the upper surface 161a of the bottom wall portion 161 of the recess 16B.

[0137] Furthermore, when viewed from the direction of the rotation axis X, the tip surface 85 of the first fin 8H has a shape that follows the slope of the upper surface 161a of the bottom wall portion 161 of the recess 16B. The tip surface 85 of the first fin 8H slopes downward from one side surface 86 and the other side surface 87 toward the vertical line VL1 (toward the center in the direction of the horizontal line HL1). Therefore, the tip surface 85 of the first fin 8H abuts against the upper surface 161a of the bottom wall portion 161 along its entire length in the direction of the horizontal line HL1.

[0138] Therefore, in the region of the breather chamber Sc where the first fin 8H is provided, the portion other than the gap CL5 on one side in the direction of the horizontal line HL1 is sealed. Note that, although the shape of the first fin 8H is described as a representative of the first fins 8 in Fig. 12, the first fins 8E to 8G (see Fig. 10) also have a shape similar to that of the first fin 8H.

[0139] 13 , the second fin 9E has a generally rectangular shape when viewed from the direction of the rotation axis X and extends in a direction along the horizontal line HL2. The tip surface 95 of the second fin 9E abuts against the lower surface 502 of the mount portion 50 over its entire length in the direction of the horizontal line HL2. The second fin 9E is also provided across the upper surface 161 a of the bottom wall portion 161 of the recess 16B and the inner wall surface 162 a of the side wall portion 162.

[0140] Further, a notch 97 is provided between the second fin 9E and the inner wall surface 163a of the side wall portion 163 in the direction of the horizontal line HL2. Therefore, a gap CL6 is provided between the second fin 9E and the inner wall surface 163a of the side wall portion 163 in the direction of the horizontal line HL2.

[0141] Therefore, in the region of the breather chamber Sc where the second fin 9E is provided, the portion other than the gap CL6 on the side of the side wall portion 163 in the direction of the horizontal line HL2 is sealed. Note that, although the shape of the second fin 9E is described in Fig. 13 as a representative of the second fins 9, the second fins 9D and 9F (see Fig. 10) also have a shape similar to that of the second fin 9E.

[0142] 11, when viewed from above, the gaps CL5 and CL6 are provided at offset positions on one side and the other side of the rotation axis X, and are arranged alternately in the direction of the rotation axis X. Therefore, the first fins 8E to 8H and the second fins 9D to 9F function as a labyrinth within the breather passage 7A.

[0143] When oil mist OM enters from the motor chamber Sa side and passes between the first fins 8E to 8H and the second fins 9D to 9F, it moves repeatedly from one side to the other of the rotation axis X, and moves toward the wall portion 120 in the direction of the rotation axis X (in the direction of the arrow in the figure).

[0144] At this time, the oil mist OM moves through the breather passage 7A while colliding with the first fins 8E to 8H and the second fins 9D to 9F, thereby reducing its kinetic energy and thermal energy and causing it to liquefy in the breather chamber Sc.

[0145] 10, oil-free air (Air) flows into the breather hole 55. The oil OL liquefied in the breather chamber Sc is returned to the motor chamber Sa through the drain portion 17, as in the embodiment. Therefore, the unit 1B according to the second modification can provide a breather structure that is more resistant to the external ejection of oil OL.

[0146] (Variation 3) In the above embodiment, the cooling unit 5 includes the mount 50 and the oil cooler 51 (see FIG. 2), but the present invention is not limited to this. For example, the cooling unit 5A may not include the oil cooler 51. In Variation 3, an example will be described in which the cooling unit 5A forms a cooling passage 56 through which cooling water W flows inside the mount 50A. Note that the oil cooler 51 may be disposed in a location separate from the cooling unit 5A in the housing HS, for example.

[0147] Fig. 14 is a diagram showing a unit 1C according to Modification 3. Fig. 15 is a diagram showing a unit 1C according to Modification 3. Fig. 15 is a schematic diagram of a cross section taken along line AA in Fig. 14. In Fig. 15, the positions of the first fins 8A to 8D are indicated by dashed lines.

[0148] As shown in FIG. 14, in a cooling section 5A of a unit 1C according to the third modification, a cooling passage 56 is provided between an upper surface 501 and a lower surface 502 of a mount portion 50A instead of the oil cooler 51.

[0149] 15, the cooling path 56 is a space that is substantially rectangular when viewed from above. The cooling path 56 is provided in a range that overlaps with the first fins 8 (8A to 8D) when viewed from above.

[0150] The cooling path 56 has long sides 561, 562 that are perpendicular to the rotation axis X, and short sides 563, 564 that connect the ends of the long sides 561, 562 and are provided along the rotation axis X. The short side 563 is provided with communication holes 56a, 56b that communicate with the discharge path P21 and the supply path P22 of the cooling water circulation section P2 described above. Therefore, the cooling path 56 uses the cooling water W that is used to cool the motor 2.

[0151] A partition wall 565 that separates the internal space of the cooling passage 56 is provided on the short side portion 563 between the communication holes 56a and 56b in the direction of the rotation axis X. The partition wall 565 is oriented along a straight line Lp. The straight line Lp is perpendicular to the rotation axis X and parallel to the long side portions 561 and 562.

[0152] The partition wall 565 protrudes from the short side portion 563, crosses the rotation axis X, and extends to the vicinity of the short side portion 564. The length of the partition wall 565 in the direction of the straight line Lp is shorter than that of the long side portion 562. A gap CL7 is provided between a tip 565a of the partition wall 565 and the short side portion 564.

[0153] The cooling water W passing through the discharge passage P21 of the cooling water circulation section P2 flows into the cooling passage 56 through the communication hole 56a. The cooling water W in the cooling passage 56 is pushed by the cooling water W sequentially flowing in from the communication hole 56a and moves toward the communication hole 56b. In this case, the cooling water W flowing in from the communication hole 56a passes through the gap CL7 between the partition wall 565 and the short side portion 564 and moves toward the communication hole 56b.

[0154] As a result, the coolant W cools the mount portion 50A and the first fins 8 (8A to 8D) as it flows through the cooling path 56. As shown in Figure 14, when the oil mist OM that has entered the breather passage 7 comes into contact with the underside 502 of the mount portion 50A and the first fins 8, the heat H of the oil mist OM is transferred to the cooling path 56 and recovered by the coolant W. As a result, the oil mist OM in the breather chamber Sc is cooled, and the thermal energy is reduced.

[0155] Furthermore, as in the embodiment, the oil mist OM that has entered the breather passage 7 moves within the breather chamber Sc while colliding with the first fin 8 and the second fin 9, thereby reducing its kinetic energy. This allows air with less oil content (Air) to move from the breather hole 55 to the breather 6. The oil OL that has liquefied within the breather chamber Sc is returned to the motor chamber Sa through the drain portion 17. Therefore, the unit 1C according to the third modification can provide a breather structure that is more resistant to the external spraying of oil OL.

[0156] The unit 1C according to the third modification has the following configuration. (1) The unit 1C has a breather passage 7 and a cooling unit 5A. A lower surface 502 of a mount portion 50A of the cooling unit 5A forms the inner peripheral surface of the housing HS. The breather passage 7 includes a first fin 8 protruding from the lower surface 502 of the mount portion 50A and a second fin 9 protruding toward the lower surface 502 of the mount portion 50A. The cooling unit 5A cools the first fin 8.

[0157] With this configuration, oil mist OM passing through the breather passage 7 is more likely to collide with the first fins 8 and the second fins 9. This makes it possible to reduce the kinetic energy of the oil mist OM within the breather passage 7. Furthermore, by cooling the first fins 8 with the cooling section 5A, it is possible to reduce the thermal energy of the oil mist OM. This reduction in kinetic energy and thermal energy makes it easier for the oil mist OM to liquefy and drip, making it possible to provide a breather structure with increased resistance to the external spraying of oil OL.

[0158] (4) The cooling unit 5A is provided in the housing HS and has the cooling passage 56 through which the cooling water W (coolant) flows.

[0159] With this configuration, the cooling water W used to cool the motor 2 can be effectively used to cool the first fins 8. This eliminates the need to provide a separate, dedicated cooler for cooling the first fins 8, which contributes to a reduction in the size of the unit 1. It also contributes to cost reduction. Although the example in which the cooling water W is used as the cooling liquid has been described in Modification 3, the cooling liquid is not limited to the cooling water W, and any liquid that can flow through the cooling path 56 may be used.

[0160] (5) When viewed in the vertical direction along the protruding direction of the first fins 8 (viewed in a predetermined direction), the cooling passages 56 have portions that overlap with the first fins 8 .

[0161] With this configuration, the cooling passages 56 can be arranged close to the first fins 8, thereby improving the efficiency of heat exchange between the cooling water W and the first fins 8.

[0162] The above-described modifications 1 to 3 can be applied not only to the embodiment but also to combinations of the modifications with each other.

[0163] Although the embodiment of the present invention has been described above, the above embodiment merely shows one application example of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configuration of the above embodiment. Appropriate modifications are possible within the scope of the technical concept of the invention.

[0164] 1, 1A to 1C: unit, 2: motor, 3: power transmission mechanism, 4: inverter case, 5, 5A: cooling section, 6: breather, 7, 7A: breather passage, 8 (8A to 8D, 8E to 8H): first fin, 9 (9A to 9C, 9D to 9F): second fin, 10: motor case, 11: case member, 12: cover member (housing main body), 16: recess, 16a: upper opening (opening), 17: drain section, 50, 50A: mount section (support section), 51: oil cooler (heat exchanger), 52: cooling water flow path (cooling path), 55: breather hole, 56: cooling path, CL1 to CL7: gap, HS: housing, OL: oil, OM: oil mist, Sa: motor chamber, Sb: gear chamber, Sc: breather chamber, Sd: inverter chamber, W: cooling water (cooling liquid), X: rotating shaft

Claims

1. A unit having: a breather passage including a first fin protruding from the inner peripheral surface of a housing; and a second fin protruding toward the inner peripheral surface of the housing; and a cooling section that cools the first fin.

2. A unit according to claim 1, wherein the cooling section is configured as a heat exchanger separate from the housing, which exchanges heat between the oil in the housing and a coolant other than the oil.

3. A unit according to claim 2, wherein the heat exchanger has a portion that overlaps with the first fin when viewed in a predetermined direction.

4. A unit according to claim 1, wherein the cooling portion is provided in the housing and configured as a cooling passage through which a cooling liquid flows.

5. A unit according to claim 4, wherein, when viewed in a predetermined direction, the cooling passage has a portion that overlaps with the first fin.

6. A unit according to any one of claims 1 to 5, wherein the housing comprises a housing main body and a support portion that supports the first fin, and the support portion is inserted into an opening in the housing main body.

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