Power transmission device and vehicle

Abstract

Protecting the power transmission device from external heat. The power transmission device includes a motor, a gear mechanism connected downstream of the motor, and a housing for storing the gear mechanism and lubricating oil. A first cooling housing is formed around the periphery of the motor to introduce coolant for cooling the motor. A second cooling housing is formed around the periphery of the housing and is connected to the first cooling housing so that the coolant can flow between the second cooling housing and the first cooling housing.

Description

Technical Field

[0001] The present invention relates to a power transmission device and a vehicle. Background Art

[0002] Patent Document 1 discloses a power transmission device for an electric vehicle including a bevel gear type differential mechanism and a planetary gear mechanism.

[0003] This planetary gear mechanism includes a stepped pinion having large planetary gears and small planetary gears.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 8-240254 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] A structure is required to protect the power transmission device from external heat.

[0009] Technical solutions to solve problems

[0010] One embodiment of the present invention provides a power transmission device having:

[0011] motor;

[0012] a gear mechanism connected downstream of the motor;

[0013] A box housing the gear mechanism and lubricating oil.

[0014] A first cooling box is formed on the outer periphery of the motor to introduce a cooling liquid to cool the motor.

[0015] A second cooling box is formed on the outer periphery of the box, and the second cooling box is connected to the first cooling box so that a coolant can flow therebetween.

[0016] In addition, a certain embodiment of the present invention provides a vehicle,

[0017] Having a heat source and a power transmission device, wherein

[0018] The power transmission device comprises:

[0019] motor;

[0020] a gear mechanism connected downstream of the motor;

[0021] A box housing the gear mechanism and lubricating oil.

[0022] A first cooling box is formed on the outer periphery of the motor to introduce a cooling liquid to cool the motor.

[0023] A second cooling box is formed on the outer periphery of the box, and the second cooling box is connected to the first cooling box so that a coolant can flow therebetween.

[0024] The heat source is arranged on the second cooling box side.

[0025] Effects of the Invention

[0026] According to one embodiment of the present invention, the power transmission device can be protected from external heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a power transmission device.

[0028] Figure 2 It is a schematic diagram of a cross section of a power transmission device.

[0029] Figure 3 This is an enlarged view of the area surrounding the planetary reduction gear of the power transmission device.

[0030] Figure 4 This is an enlarged view of the differential mechanism and its surroundings of the power transmission device.

[0031] Figure 5 This is a perspective view of the differential mechanism of the power transmission device.

[0032] Figure 6 This is an exploded perspective view of the differential mechanism of the power transmission device.

[0033] Figure 7 It is a diagram for explaining the oil shielding portion.

[0034] Figure 8 It is a diagram for explaining the oil shielding portion.

[0035] Figure 9 It is a diagram for explaining the oil shielding portion.

[0036] Figure 10 It is a diagram for explaining the oil shielding portion.

[0037] Figure 11 It is a diagram for explaining the oil shielding portion.

[0038] Figure 12 It is a diagram for explaining the oil shielding portion.

[0039] Figure 13 It is an enlarged view of the lower part of the fourth box body and the surrounding area of ​​the cooling chamber.

[0040] Figure 14 This is a diagram showing the cooling chamber as viewed from the peripheral wall side of the fourth housing.

[0041] Figure 15 This is a diagram showing a state where the cover of the cooling chamber is removed.

[0042] Figure 16 It is a diagram explaining the flow of coolant.

[0043] Figure 17 It is a figure which shows the structure of a cover part.

[0044] Figure 18 It is a diagram for explaining the assembly of the spacer to the cover.

[0045] Figure 19 It is a diagram for explaining the flow of coolant in the cooling chamber.

[0046] Figure 20 is a schematic diagram showing a series hybrid vehicle.

[0047] Figure 21 It is a diagram showing the arrangement of a power transmission device and an exhaust pipe.

[0048] Figure 22 It is a diagram showing the arrangement of a power transmission device and an exhaust pipe. DETAILED DESCRIPTION

[0049] Hereinafter, embodiments of the present invention will be described.

[0050] Figure 1 It is a schematic diagram illustrating the power transmission device 1 according to the present embodiment.

[0051] Figure 2 It is a schematic diagram illustrating a cross section of the power transmission device 1 according to the present embodiment.

[0052] Figure 3 It is an enlarged view of the periphery of the planetary reduction gear 4 of the power transmission device 1 .

[0053] Figure 4 It is an enlarged view of the differential mechanism 5 and its surroundings of the power transmission device 1 .

[0054] like Figure 1 As shown, the power transmission device 1 includes a motor 2 and a planetary reduction gear 4 (reduction mechanism) that reduces the output rotation of the motor 2 and inputs the reduced rotation to a differential mechanism 5. The power transmission device 1 also includes drive shafts DA and DB and a parking lock mechanism 3.

[0055] In the power transmission device 1 , a parking lock mechanism 3 , a planetary reduction gear 4 , a differential mechanism 5 , and drive shafts DA and DB are provided along a transmission path of output rotation of the motor 2 about the rotation axis X. The axes of the drive shafts DA and DB are coaxial with the rotation axis X of the motor 2 .

[0056] In the power transmission device 1 , the output rotation of the motor 2 is reduced by the planetary reduction gear 4 and input to the differential mechanism 5 , and then transmitted to the left and right drive wheels W, W of the vehicle equipped with the power transmission device 1 via the drive shafts DA, DB.

[0057] Here, the planetary reduction gear 4 is connected to the downstream of the motor 2. The differential mechanism 5 is connected to the downstream of the planetary reduction gear 4. The drive shafts DA and DB are connected to the downstream of the differential mechanism 5.

[0058] like Figure 2 As shown, the main body housing 10 of the power transmission device 1 includes a first housing 11 housing the motor 2 and a second housing 12 inserted outside the first housing 11. The main body housing 10 also includes a third housing 13 assembled to the first housing 11 and a fourth housing 14 assembled to the second housing 12.

[0059] The first housing 11 includes a cylindrical support wall portion 111 and a flange-shaped joint portion 112 provided at one end 111 a of the support wall portion 111 .

[0060] The first housing 11 is provided so that the support wall portion 111 is oriented along the direction of the rotation axis X of the motor 2 . The motor 2 is housed inside the support wall portion 111 .

[0061] The joint portion 112 is provided in a direction perpendicular to the rotation axis X. The joint portion 112 is formed to have a larger outer diameter than the support wall portion 111 .

[0062] The second housing 12 includes a cylindrical peripheral wall portion 121 , a flange-shaped joint portion 122 provided at one end 121 a of the peripheral wall portion 121 , and a flange-shaped joint portion 123 provided at the other end 121 b of the peripheral wall portion 121 .

[0063] The peripheral wall portion 121 is formed with an inner diameter that can be externally inserted into the support wall portion 111 of the first housing 11 .

[0064] The first housing 11 and the second housing 12 are assembled to each other by inserting the peripheral wall 121 of the second housing 12 onto the support wall 111 of the first housing 11 .

[0065] The joint portion 122 on the side of the one end 121a of the peripheral wall portion 121 contacts the joint portion 112 of the first housing 11 in the direction of the rotation axis X. These joint portions 122 and 112 are connected to each other by bolts (not shown).

[0066] In the first housing 11 , a plurality of grooves 111 b are provided on the outer periphery of the support wall portion 111 . The plurality of grooves 111 b are provided at intervals in the direction of the rotation axis X. Each groove 111 b is provided over the entire circumference around the rotation axis X in the circumferential direction.

[0067] The peripheral wall 121 of the second housing 12 is inserted into the support wall 111 of the first housing 11. The opening of the groove 111b is closed by the peripheral wall 121. A plurality of cooling paths CP (first cooling housing) through which the coolant CL flows are formed between the support wall 111 and the peripheral wall 121.

[0068] The inlet 124a of the coolant CL is provided on the side of the joint 122 of the peripheral wall portion 121. The outlet 124b of the coolant CL is provided on the side of the joint 123 of the peripheral wall portion 121. The inlet 124a and the outlet 124b are holes that pass through the peripheral wall portion 121 in the radial direction of the rotation axis X. A pipe (not shown) through which the coolant CL flows is connected to each of the inlet 124a and the outlet 124b. The coolant CL circulates in the pipe (not shown) provided inside the vehicle through a water pump (not shown). The coolant CL is introduced from the inlet 124a into the cooling path CP to cool the motor 2. After cooling the motor 2, the coolant CL is discharged from the outlet 124b. The coolant CL is introduced into the cooling chamber CR provided in the fourth case 14 described later through the pipe (not shown).

[0069] Annular grooves 111c, 111c are formed on both sides of the region where the groove 111b is provided in the outer periphery of the support wall portion 111 of the first housing 11. Seal rings 113, 113 are fitted externally in the annular grooves 111c, 111c.

[0070] These seal rings 113 are pressed against the inner periphery of the peripheral wall portion 121 inserted outside the support wall portion 111 , thereby sealing the gap between the outer periphery of the support wall portion 111 and the inner periphery of the peripheral wall portion 121 .

[0071] A wall portion 120 extending to the inner diameter side is provided at the other end 121b of the second housing 12. The wall portion 120 is provided in a direction perpendicular to the rotation axis X. An opening 120a is formed in a region of the wall portion 120 intersecting the rotation axis X, through which the drive shaft DA is inserted.

[0072] A cylindrical motor support portion 125 surrounding the opening 120 a is provided on the surface of the wall portion 120 on the motor 2 side (right side in the figure).

[0073] The motor support portion 125 is inserted into the inner side of the coil end 253b described later. The motor support portion 125 faces the end portion 21b of the rotor core 21 with a gap in the direction of the rotation axis X therebetween.

[0074] The peripheral wall portion 121 of the second case 12 has a radial thickness thicker in a lower region in the vertical direction relative to the state in which the power transmission device 1 is mounted on the vehicle than in an upper region.

[0075] In this radially thick region, an oil reservoir 128 is provided penetrating in the direction of the rotation axis X.

[0076] The oil reservoir 128 is connected to an axial oil passage 138 provided in the joint 132 of the third case 13 via the communication hole 112a. The communication hole 112a is provided in the joint 112 of the first case 11.

[0077] The third housing 13 includes a wall portion 130 perpendicular to the rotation axis X. A joint portion 132 having an annular shape when viewed from the rotation axis X direction is provided on the outer periphery of the wall portion 130 .

[0078] The third case 13 is located on the opposite side of the differential mechanism 5 (right side in the figure) from the first case 11. The joint 132 of the third case 13 is joined to the joint 112 of the first case 11 along the rotation axis X. The third case 13 and the first case 11 are connected to each other using bolts (not shown). In this state, the opening of the support wall 111 of the first case 11 on the side of the joint 122 (right side in the figure) is blocked by the third case 13.

[0079] In the third housing 13 , an insertion hole 130 a for the drive shaft DA is provided in the center of the wall portion 130 .

[0080] A lip seal RS is provided on the inner periphery of the insertion hole 130a. The lip seal RS elastically contacts the outer periphery of the drive shaft DA with a lip portion (not shown). The lip seal RS seals the gap between the inner periphery of the insertion hole 130a and the outer periphery of the drive shaft DA.

[0081] A peripheral wall portion 131 surrounding the insertion hole 130a is provided on the surface of the wall portion 130 on the first housing 11 side (left side in the figure). The drive shaft DA is supported on the inner periphery of the peripheral wall portion 131 via a bearing B4.

[0082] A motor support portion 135 is provided on the motor 2 side (left side in the figure) when viewed from the peripheral wall portion 131. The motor support portion 135 is formed in a cylindrical shape surrounding the rotation axis X at a distance.

[0083] A cylindrical connecting wall 136 is connected to the outer periphery of the motor support portion 135. The connecting wall 136 has a larger outer diameter than the peripheral wall portion 131 on the wall portion 130 side (the right side in the figure). The connecting wall 136 is oriented along the rotation axis X and extends away from the motor 2. The connecting wall 136 connects the motor support portion 135 to the wall portion 130 of the third housing 13.

[0084] The motor support portion 135 is supported by the third housing 13 via the connection wall 136. One end 20a of the motor shaft 20 passes through the inside of the motor support portion 135 from the motor 2 side toward the peripheral wall portion 131 side.

[0085] A bearing B1 is supported on the inner periphery of the motor support portion 135. The outer periphery of the motor shaft 20 is supported by the motor support portion 135 via the bearing B1.

[0086] A lip seal RS is provided adjacent to the bearing B1 .

[0087] In the third housing 13, an oil hole 136a (described later) is formed on the inner periphery of the connecting wall 136. Oil OL flows from the oil hole 136a into the space (internal space Sc) surrounded by the connecting wall 136. A lip seal RS is provided to prevent the oil OL in the connecting wall 136 from flowing toward the motor 2.

[0088] The fourth case 14 includes a peripheral wall portion 141 surrounding the outer periphery of the planetary reduction gear 4 and the differential mechanism 5, and a flange-shaped joint portion 142 provided at the end of the peripheral wall portion 141 on the second case 12 side. The fourth case 14 functions as a case that houses the gear mechanism, namely, the planetary reduction gear 4 and the differential mechanism 5.

[0089] The fourth case 14 is located on the differential mechanism 5 side (left side in the figure) when viewed from the second case 12 .

[0090] The engaging portion 142 of the fourth housing 14 engages with the engaging portion 123 of the second housing 12 in the rotation axis X direction.

[0091] The fourth housing 14 and the second housing 12 are connected to each other by bolts (not shown).

[0092] A motor chamber Sa accommodating the motor 2 and a gear chamber Sb accommodating the planetary reduction gear 4 and the differential mechanism 5 are formed inside the main body case 10 of the power transmission device 1 .

[0093] The motor chamber Sa is formed inside the first housing 11 between the wall portion 120 of the second housing 12 and the wall portion 130 of the third housing 13 .

[0094] The gear chamber Sb is formed between the wall portion 120 of the second case 12 and the peripheral wall portion 141 of the fourth case 14 on the inner diameter side of the fourth case 14 .

[0095] A plate member 8 is provided inside the gear chamber Sb.

[0096] The plate member 8 is fixed to the fourth case 14 with bolts B.

[0097] The plate member 8 partitions the gear chamber Sb into a first gear chamber Sb1 accommodating the planetary reduction gear 4 and the differential mechanism 5 , and a second gear chamber Sb2 accommodating the parking lock mechanism 3 .

[0098] The second gear chamber Sb2 is located between the first gear chamber Sb1 and the motor chamber Sa in the direction of the rotation axis X.

[0099] The motor 2 includes a cylindrical motor shaft 20 , a cylindrical rotor core 21 inserted onto the motor shaft 20 , and a stator core 25 surrounding the outer circumference of the rotor core 21 at intervals.

[0100] In the motor shaft 20 , bearings B1 and B1 are fixedly inserted on both sides of the rotor core 21 .

[0101] The bearing B1 located on one end 20a of the motor shaft 20 (right side in the figure) is supported by the inner periphery of the motor support portion 135 of the third housing 13 when viewed from the rotor core 21. The bearing B1 located on the other end 20b is supported by the inner periphery of the cylindrical motor support portion 125 of the second housing 12.

[0102] The motor support portions 135 and 125 are arranged to face the one end portion 21 a and the other end portion 21 b of the rotor core 21 with a gap in the rotation axis X direction, on the inner diameter side of coil ends 253 a and 253 b described later.

[0103] The rotor core 21 is formed by laminating a plurality of silicon steel sheets. Each of the silicon steel sheets is externally inserted into the motor shaft 20 in a state where relative rotation with the motor shaft 20 is restricted.

[0104] The silicon steel sheet is annular when viewed from the rotation axis X of the motor shaft 20. On the outer periphery of the silicon steel sheet, magnets having N poles and S poles (not shown) are alternately provided in the circumferential direction around the rotation axis X.

[0105] The stator core 25 surrounding the outer periphery of the rotor core 21 is formed by laminating a plurality of electromagnetic steel sheets. The stator core 25 is fixed to the inner periphery of the cylindrical support wall portion 111 of the first casing 11 .

[0106] Each of the electromagnetic steel sheets includes an annular yoke portion 251 fixed to the inner periphery of the support wall portion 111 and a pole tooth portion 252 protruding from the inner periphery of the yoke portion 251 toward the rotor core 21 .

[0107] In this embodiment, the stator core 25 is configured such that the winding 253 is distributedly wound across a plurality of teeth 252. The stator core 25 is longer in the rotation axis X direction than the rotor core 21 by the coil ends 253a and 253b protruding in the rotation axis X direction.

[0108] Alternatively, a stator core may be employed in which windings are concentratedly wound around each of the plurality of pole teeth 252 protruding toward the rotor core 21 .

[0109] An opening 120 a is provided in the wall portion 120 (motor support portion 125 ) of the second case 12 . The other end 20 b of the motor shaft 20 passes through the opening 120 a on the differential mechanism 5 side (left side in the figure) and is located in the fourth case 14 .

[0110] The other end 20 b of the motor shaft 20 is located inside the fourth housing 14 and faces a side gear 54A, which will be described later, with a gap in the direction of the rotation axis X therebetween.

[0111] like Figure 3 As shown, the motor shaft 20 has a step 201 in the area located inside the fourth housing 14. The step 201 is located near the motor support 125. The lip seal RS supported on the inner periphery of the motor support 125 abuts against the outer periphery of the area between the step 201 and the bearing B1.

[0112] The lip seal RS defines a motor chamber Sa accommodating the motor 2 and a gear chamber Sb in the fourth housing 14 .

[0113] Oil OL for lubricating the planetary reduction gear 4 and the differential mechanism 5 is enclosed in the inner diameter side of the fourth case 14 (see Figure 2 ).

[0114] The lip seal RS is provided to prevent the oil OL from flowing into the motor chamber Sa.

[0115] like Figure 3 As shown, on the motor shaft 20 , the region from the step portion 201 to the vicinity of the other end 20 b forms a fitting portion 202 having a spline provided on the outer periphery.

[0116] The parking gear 30 and the sun gear 41 are spline-fitted to the outer circumference of the fitting portion 202 .

[0117] One side surface of the parking gear 30 contacts the step portion 201 (right side in the figure). One end 410a of the cylindrical base 410 of the sun gear 41 contacts the other side surface of the parking gear 30 (left side in the figure).

[0118] A nut N threadedly engaged with the other end 20 b of the motor shaft 20 is press-fitted to the other end 410 b of the base 410 from the direction of the rotation axis X.

[0119] The sun gear 41 and the parking gear 30 are provided so as to be non-rotatable relative to the motor shaft 20 in a state of being sandwiched between the nut N and the step portion 201 .

[0120] The sun gear 41 has a tooth portion 411 on the outer periphery of the other end 20b side of the motor shaft 20. The large-diameter gear portion 431 of the stepped pinion 43 meshes with the outer periphery of the tooth portion 411.

[0121] The stepped pinion 43 includes a large-diameter gear portion 431 that meshes with the sun gear 41 and a small-diameter gear portion 432 having a smaller diameter than the large-diameter gear portion 431 .

[0122] The stepped pinion 43 is a gear component in which a large-diameter gear portion 431 and a small-diameter gear portion 432 are arranged in an axis X1 direction parallel to the rotation axis X and integrally provided.

[0123] The large-diameter gear portion 431 is formed to have an outer diameter R1 that is larger than an outer diameter R2 of the small-diameter gear portion 432 .

[0124] The stepped pinion 43 is provided in a direction along the axis X1. In this state, the large-diameter gear portion 431 is located on the motor 2 side (right side in the figure).

[0125] The outer periphery of the small-diameter gear portion 432 meshes with the inner periphery of the ring gear 42. The ring gear 42 is annularly shaped, surrounding the rotation axis X at intervals. A plurality of engaging teeth 421 projecting radially outward are provided on the outer periphery of the ring gear 42. The plurality of engaging teeth 421 are spaced apart from one another in the circumferential direction around the rotation axis X.

[0126] The ring gear 42 has engaging teeth 421 provided on the outer periphery thereof spline-fitted with teeth 146a provided on the support wall 146 of the fourth case 14. The ring gear 42 is restricted from rotating about the rotation axis X.

[0127] The stepped pinion 43 includes a through hole 430 that penetrates the inner diameter sides of the large-diameter gear portion 431 and the small-diameter gear portion 432 in the axis X1 direction.

[0128] The stepped pinion 43 is rotatably supported on the outer periphery of a pinion shaft 44 that passes through the through hole 430 via needle roller bearings NB, NB.

[0129] On the outer periphery of the pinion shaft 44 , an intermediate spacer MS is interposed between a needle roller bearing NB supporting the inner periphery of the large-diameter gear portion 431 and a needle roller bearing NB supporting the inner periphery of the small-diameter gear portion 432 .

[0130] like Figure 4 As shown, an in-shaft oil passage 440 is provided inside the pinion shaft 44. The in-shaft oil passage 440 passes through the pinion shaft 44 from one end 44a to the other end 44b along the axis X1.

[0131] The pinion shaft 44 is provided with oil holes 442 and 443 that allow the shaft oil passage 440 to communicate with the outer periphery of the pinion shaft 44 .

[0132] The oil hole 443 is opened in a region where a needle roller bearing NB that supports the inner periphery of the large-diameter gear portion 431 is provided.

[0133] The oil hole 442 is opened in a region where a needle roller bearing NB that supports the inner periphery of the small-diameter gear portion 432 is provided.

[0134] On the pinion shaft 44 , oil holes 443 , 442 are formed in the area where the stepped pinion 43 is inserted.

[0135] Furthermore, the pinion shaft 44 is provided with an introduction passage 441 for introducing the oil OL into the intra-shaft oil passage 440 .

[0136] The introduction path 441 is opened in the outer periphery of the pinion shaft 44 in a region located within a support hole 71 a of the second housing portion 7 , which will be described later. The introduction path 441 connects the shaft oil path 440 to the outer periphery of the pinion shaft 44 .

[0137] The inner periphery of the support hole 71a is provided with an internal oil passage 781. The internal oil passage 781 allows the outer periphery of the guide portion 78 protruding from the base portion 71 of the second case portion 7 to communicate with the support hole 71a.

[0138] The housing oil passage 781 is inclined relative to the axis X1 in a cross-sectional view along the axis X1. The housing oil passage 781 is inclined in a direction approaching the slit 710 provided in the base 71 as it approaches the rotation axis X side.

[0139] The oil OL lifted by the differential case 50 described later flows into the case oil passage 781. The oil OL moving radially outward also flows into the case oil passage 781 due to the centrifugal force generated by the rotation of the differential case 50.

[0140] Oil OL flowing from the housing oil passage 781 into the inlet passage 441 flows into the pinion shaft 44's in-shaft oil passage 440. The oil OL flowing into the in-shaft oil passage 440 is discharged radially outward from the oil holes 442 and 443. The oil OL discharged from the oil holes 442 and 443 lubricates the needle roller bearing NB externally inserted into the pinion shaft 44.

[0141] The pinion shaft 44 is provided with a through hole 444 on the other end 44b side of the region provided with the introduction path 441. The through hole 444 penetrates the pinion shaft 44 in the radial direction.

[0142] The pinion shaft 44 is provided so that its through-hole 444 and an insertion hole 782 on the second housing portion 7, described later, are aligned in phase about the axis X1. A positioning pin P, inserted into the insertion hole 782, passes through the through-hole 444 of the pinion shaft 44. This allows the pinion shaft 44 to be supported by the second housing portion 7 while its rotation about the axis X1 is restricted.

[0143] like Figure 4 As shown, a region protruding from the stepped pinion 43 at one longitudinal end 44a of the pinion shaft 44 serves as a first shaft portion 445. The first shaft portion 445 is supported by a support hole 61a provided in the first case portion 6 of the differential case 50.

[0144] A region protruding from the stepped pinion 43 at the other longitudinal end 44b of the pinion shaft 44 serves as a second shaft portion 446. The second shaft portion 446 is supported by a support hole 71a provided in the second case portion 7 of the differential case 50.

[0145] Here, the first shaft portion 445 is a region of the pinion shaft 44 on the side where the one end 44a of the stepped pinion 43 is not inserted. The second shaft portion 446 is a region of the pinion shaft 44 on the side where the other end 44b of the stepped pinion 43 is not inserted.

[0146] In the pinion shaft 44 , the second shaft portion 446 is longer than the first shaft portion 445 in terms of length in the axis X1 direction.

[0147] Hereinafter, the main structure of the differential mechanism 5 will be described.

[0148] Figure 5 It is a perspective view of the periphery of the differential case 50 of the differential mechanism 5 .

[0149] Figure 6 It is an exploded perspective view of the periphery of the differential case 50 of the differential mechanism 5 .

[0150] like Figures 4 to 6 As shown, the differential case 50 of the differential mechanism 5 is formed by assembling the first case portion 6 and the second case portion 7 in the direction of the rotation axis X. In this embodiment, the first case portion 6 and the second case portion 7 of the differential case 50 have the function of a planetary gear carrier that supports the pinion shaft 44 of the planetary reduction gear 4.

[0151] like Figure 6 As shown, a pinion mating shaft 51 and a pinion mating gear 52 are arranged between the first housing portion 6 and the second housing portion 7 of the differential case 50. Three pinion mating gears 52 and three pinion mating shafts 51 are provided.

[0152] The pinion mating shafts 51 are arranged at equal intervals in the circumferential direction around the rotation axis X.

[0153] The inner diameter side end portions of the respective pinion mating shafts 51 are connected to a common connection portion 510 .

[0154] One pinion mating gear 52 is externally inserted on each pinion mating shaft 51. Each pinion mating gear 52 contacts the connection portion 510 from the radially outer side of the rotation axis X.

[0155] In this state, the pinion mating gears 52 are each rotatably supported by the pinion mating shaft 51 .

[0156] like Figure 4As shown, a spherical washer 53 is externally inserted on the pinion mating shaft 51. The spherical washer 53 contacts the spherical outer periphery of the pinion mating gear 52.

[0157] In the differential case 50 , the side gear 54A is located on one side of the connection portion 510 in the direction of the rotation axis X, and the side gear 54B is located on the other side. The side gear 54A is rotatably supported by the first case portion 6 , and the side gear 54B is rotatably supported by the second case portion 7 .

[0158] The side gear 54A meshes with the three pinion mating gears 52 from one side in the direction of the rotation axis X. The side gear 54B meshes with the three pinion mating gears 52 from the other side in the direction of the rotation axis X.

[0159] like Figure 6 As shown, the first housing portion 6 has an annular base portion 61. The base portion 61 is a plate-shaped member having a thickness W61 in the direction of the rotation axis X.

[0160] like Figure 4 As shown, an opening 60 is provided in the center of the base 61. A cylindrical wall portion 611 is provided on the surface of the base 61 opposite to the second housing portion 7 (right side in the figure) to surround the opening 60. The outer periphery of the cylindrical wall portion 611 is supported by the plate member 8 via the bearing B3.

[0161] like Figure 6 As shown, three connecting beams 62 extending toward the second case portion 7 are provided on the surface of the base portion 61 on the second case portion 7 side.

[0162] The connecting beams 62 are provided at equal intervals in the circumferential direction around the rotation axis X. The connecting beam 62 includes a base portion 63 perpendicular to the base portion 61 and a connecting portion 64 having a width wider than that of the base portion 63 .

[0163] like Figure 4 As shown, a support groove 65 for supporting the pinion mating shaft 51 is provided on the front end surface of the connecting portion 64 .

[0164] An arc portion 641 is formed on the inner diameter side (rotation axis X side) of the coupling portion 64 in a shape that follows the outer circumference of the pinion mating gear 52 .

[0165] The outer periphery of the pinion mating gear 52 is supported by the arc portion 641 via a spherical washer 53 .

[0166] A gear support portion 66 is connected to the boundary portion between the base portion 63 and the connection portion 64 of the connection beam 62 . The gear support portion 66 is provided in a direction perpendicular to the rotation axis X. A through hole 660 is formed in the center portion of the gear support portion 66 .

[0167] A recess 661 surrounding the through hole 660 is provided on the surface of the gear support portion 66 on the opposite side (left side in the figure) from the base portion 61. The recess 661 accommodates the annular washer 55 supporting the back surface of the side gear 54A.

[0168] A cylindrical wall portion 541 is provided on the back surface of the side gear 54A, and a washer 55 is externally inserted into the cylindrical wall portion 541 .

[0169] like Figure 6 As shown, the connecting beams 62 , 62 of the base portion 61 are arranged at intervals in the circumferential direction around the rotation axis X. A support hole 61 a for the pinion shaft 44 is formed in a region between the connecting beams 62 , 62 .

[0170] The base 61 is provided with a boss portion 616 surrounding the support hole 61a. Figure 3 As shown, the washer Wc externally inserted into the pinion shaft 44 contacts the boss portion 616 from the direction of the rotation axis X.

[0171] like Figure 6 As shown, an oil groove 617 is provided in the base portion 61, extending from the central opening 60 to the boss portion 616. The oil groove 617 is formed in a tapered shape, with its width in the circumferential direction around the rotation axis X becoming narrower as it approaches the boss portion 616. The oil groove 617 is connected to an oil groove 618 provided in the boss portion 616.

[0172] The connecting portion 64 is provided with bolt holes 67 , 67 on both sides of the support groove 65 .

[0173] The connecting portion 74 on the second case portion 7 side is joined to the connecting portion 64 on the first case portion 6 in the direction of the rotation axis X. Bolts B (see FIG. 1 ) that penetrate the connecting portion 74 on the second case portion 7 side are screwed into the bolt holes 67, 67. Figure 5 The first housing portion 6 and the second housing portion 7 are joined to each other using bolts B.

[0174] like Figure 6 As shown, the second housing part 7 has an annular base 71 .

[0175] like Figure 4 As shown, the base portion 71 is a plate-shaped member having a thickness W71 in the direction of the rotation axis X.

[0176] A through hole 70 is provided in the center of the base portion 71 so as to penetrate the base portion 71 in the thickness direction.

[0177] A cylindrical wall portion 72 surrounding the through hole 70 and a peripheral wall portion 73 surrounding the cylindrical wall portion 72 at a distance therefrom are provided on the surface of the base portion 71 on the opposite side (left side in the figure) from the first case portion 6 .

[0178] A protrusion 73 a that protrudes toward the rotation axis X is provided at the front end of the peripheral wall portion 73 . The protrusion 73 a is provided over the entire circumference of the rotation axis X.

[0179] like Figure 6 As shown, three support holes 71a for the pinion shaft 44 are opened on the outer diameter side of the peripheral wall portion 73. The three support holes 71a are arranged in the circumferential direction around the rotation axis X at intervals.

[0180] Three slits 710 penetrating the base portion 71 in the thickness direction are provided on the inner diameter side of the peripheral wall portion 73 .

[0181] The slit 710 is formed in an arc shape along the inner circumference of the peripheral wall portion 73 when viewed from the direction of the rotation axis X. The slit 710 is formed in a predetermined angular range in the circumferential direction around the rotation axis X.

[0182] In the second case portion 7 , the slits 710 are arranged at intervals from each other in the circumferential direction around the rotation axis X. Each of the slits 710 is provided across the inner diameter side of the support hole 71 a in the circumferential direction around the rotation axis X.

[0183] Three protruding walls 711 are provided between adjacent slits 710, 710 in the circumferential direction around the rotation axis, protruding in a direction away from the first housing portion 6. The protruding walls 711 extend linearly in the radial direction of the rotation axis X. The protruding walls 711 are provided across the outer diameter side peripheral wall portion 73 and the inner diameter side cylindrical wall portion 72.

[0184] The three protruding walls 711 are provided at intervals from each other in the circumferential direction around the rotation axis X. The protruding walls 711 are provided with a phase shift of approximately 45 degrees relative to the slit 710 in the circumferential direction around the rotation axis X.

[0185] Bolt receiving portions 76 , 76 recessed toward the first case portion 6 are provided between adjacent support holes 71 a , 71 a in the circumferential direction around the rotation axis X on the outer diameter side of the peripheral wall portion 73 .

[0186] A bolt insertion hole 77 is formed inside the bolt receiving portion 76. The insertion hole 77 penetrates the base portion 71 in the thickness direction (rotation axis X direction).

[0187] like Figure 4 As shown, a connection portion 74 that protrudes toward the first case portion 6 is provided on the surface of the base portion 71 on the first case portion 6 side (right side in the figure).

[0188] The connection portions 74 are provided in the same number as the connection beams 62 on the first case portion 6 side.

[0189] A support groove 75 for supporting the pinion mating shaft 51 is provided on the front end surface of the coupling portion 74 .

[0190] An arc portion 741 is provided on the inner diameter side (rotation axis X side) of the coupling portion 74 so as to follow the outer circumference of the pinion mating gear 52 .

[0191] The outer periphery of the pinion mating gear 52 is supported on the arc portion 741 via the spherical washer 53 .

[0192] In the second housing 7 , an annular washer 55 supporting the back surface of the side gear 54B is placed on the surface 71 b of the base 71 . A cylindrical wall 540 is provided on the back surface of the side gear 54B. The washer 55 is externally inserted into the wall 540 .

[0193] The base 71 of the second housing portion 7 is provided with guide portions 78. The guide portions 78 protrude toward the first housing portion 6 (right side in the figure). The guide portions 78 are provided in the same number as the boss portions 616 of the first housing portion 6.

[0194] like Figure 4 As shown, in a cross-section along the axis X1, the pinion shaft 44 is inserted from the first housing portion 6 side into the support hole 71a of the guide portion 78. The pinion shaft 44 is positioned by a positioning pin P while being restricted from rotating about the axis X1.

[0195] In this state, the small-diameter gear portion 432 of the stepped pinion 43 externally inserted into the pinion shaft 44 abuts against the guide portion 78 from the axis X1 direction with the washer Wc interposed therebetween.

[0196] In the differential case 50, a bearing B2 is externally inserted into the cylindrical wall portion 72 of the second case portion 7. The bearing B2 externally inserted into the cylindrical wall portion 72 is held by the support portion 145 of the fourth case 14. The cylindrical wall portion 72 of the differential case 50 is rotatably supported by the fourth case 14 via the bearing B2.

[0197] The drive shaft DB that passes through the opening 145 a of the fourth housing 14 is inserted into the support portion 145 in the direction of the rotation axis X. The drive shaft DB is rotatably supported by the support portion 145 .

[0198] A lip seal RS is fixed to the inner periphery of the opening 145a. A lip portion (not shown) of the lip seal RS elastically contacts the outer periphery of the cylindrical wall portion 540 of the side gear 54B externally inserted on the drive shaft DB.

[0199] As a result, the gap between the outer periphery of the cylindrical wall portion 540 of the side gear 54B and the inner periphery of the opening 145 a is sealed.

[0200] like Figure 2 As shown, the first case portion 6 of the differential case 50 is supported by the plate member 8 via the bearing B3 externally inserted into the cylindrical wall portion 611 .

[0201] The drive shaft DA that has passed through the insertion hole 130 a of the third housing 13 is inserted into the first case portion 6 from the rotation axis X direction.

[0202] The drive shaft DA is provided so as to cross the motor shaft 20 of the motor 2 and the inner diameter side of the sun gear 41 of the planetary reduction gear 4 in the direction of the rotation axis X.

[0203] like Figure 4 As shown, side gears 54A, 54B are spline-fitted to the outer circumferences of the front ends of drive shafts DA, DB inside the differential case 50. The side gears 54A, 54B and the drive shafts DA, DB are coupled so as to be rotatable integrally about the rotation axis X.

[0204] In this state, the side gears 54A and 54B are arranged to face each other with a gap therebetween in the direction of the rotation axis X. The connecting portion 510 of the pinion mating shaft 51 is located between the side gears 54A and 54B.

[0205] In this embodiment, three pinion mating shafts 51 extend radially outward from the connecting portion 510. A pinion mating gear 52 is supported on each of the pinion mating shafts 51. The pinion mating gears 52 are assembled to a side gear 54A located on one side of the rotation axis X direction and a side gear 54B located on the other side, with their teeth meshing with each other.

[0206] exist Figure 2 As shown by a bold line in FIG, an oil reservoir OP for storing lubricating oil OL is formed in a lower portion of the gear chamber Sb of the fourth case 14. The lower portion of the differential case 50 is located in the oil reservoir OP.

[0207] In the present embodiment, when the connecting beam 62 is located at the lowermost side, the oil OL is stored to a height at which the connecting beam 62 is located in the oil reservoir OP.

[0208] The oil OL in the oil reservoir OP is scooped up by the differential case 50 rotating about the rotation axis X when the output rotation of the motor 2 is transmitted.

[0209] Figures 7 to 12 It is a diagram for explaining the oil-shielding portion 15 .

[0210] Figure 7 This is a plan view of the fourth housing 14 as viewed from the third housing 13 side.

[0211] Figure 8 Observed from above Figure 7 A perspective view of the oil baffle 15 is shown.

[0212] Figure 9 It is a plan view of the fourth case 14 as viewed from the third case 13 side, and shows a state where the differential case 50 is arranged.

[0213] Figure 10 Observed from above Figure 9 A perspective view of the oil baffle 15 is shown.

[0214] Figure 11 yes Figure 9 Schematic diagram of the A-A section in .

[0215] Figure 12 1 is a schematic diagram illustrating the positional relationship between the oil shield portion 15 and the differential case 50 (the first case portion 6 and the second case portion 7 ) when the power transmission device 1 is viewed from above.

[0216] In addition, Figure 7 and Figure 9 In the figure, hatching is used to clearly indicate the positions of the joint portion 142 and the support wall portion 146 of the fourth housing 14 .

[0217] Figure 7 and Figure 9 The plumb line VL in FIG. 1 is the plumb line VL used as a reference for the installation state of the power transmission device 1 on the vehicle. When viewed from the direction of the rotation axis X, the plumb line VL is perpendicular to the rotation axis X. Furthermore, the horizontal line HL is the horizontal line HL used as a reference for the installation state of the power transmission device 1 on the vehicle. When viewed from the direction of the rotation axis X, the horizontal line HL is perpendicular to the rotation axis X and the plumb line VL.

[0218] like Figure 7 As shown, the fourth case 14 is provided with a support wall 146 that surrounds a central opening 145a at intervals when viewed from the rotation axis X. The inner side (rotation axis X) of the support wall 146 serves as the housing 140 of the differential case 50 .

[0219] A space for an oil shield portion 15 and a space for an air breather chamber 16 are formed in an upper portion of the fourth housing 14 .

[0220] A communication port 147 for communicating between the oil-spill portion 15 and the housing portion 140 of the differential case 50 is provided in a region intersecting the vertical line VL in the support wall portion 146 of the fourth case 14 .

[0221] The oil-shielding portion 15 and the breather chamber 16 are respectively located on one side (left side in the figure) and the other side (right side in the figure) of a vertical line VL perpendicular to the rotation axis X.

[0222] The oil deflector 15 is arranged at a position offset from a vertical line VL passing through the rotation center (rotation axis X) of the differential case 50. Figure 12 As shown, when the oil-spill portion 15 is viewed from above, the oil-spill portion 15 is arranged at a position offset from right above the differential case 50 .

[0223] like Figure 8As shown, the oil shield 15 is formed to extend further into the drawing than the support wall 146. A support platform 151 (shelf) is provided at the lower edge of the oil shield 15, projecting toward the front of the drawing. The support platform 151 is positioned within a range closer to the front of the drawing than the support wall 146 and further into the drawing than the joint 142 of the fourth housing 14.

[0224] like Figure 7 As shown, a portion of the support wall portion 146 is cut out to form a communication port 147 on the vertical line VL side (right side in the figure) of the oil sling 15 as viewed from the rotation axis X. The communication port 147 connects the oil sling 15 with the housing portion 140 of the differential case 50.

[0225] The communication port 147 is provided in a range crossing the vertical line VL from the breather chamber 16 side (right side in the figure) to the oil shield portion 15 side (left side in the figure) when viewed in the direction of the rotation axis X.

[0226] like Figure 9 As shown, in this embodiment, when the vehicle equipped with the power transmission device 1 travels forward, the differential case 50 rotates in the counterclockwise direction CCW around the rotation axis X as viewed from the third case 13 side.

[0227] Therefore, the oil shield 15 is located downstream in the rotational direction of the differential case 50. Furthermore, the circumferential width of the communication opening 147 is wider on the left side of the vertical line VL than on the right side. The left side of the vertical line VL is the downstream side in the rotational direction of the differential case 50, while the right side is the upstream side. As a result, most of the oil OL stirred up by the differential case 50 rotating about the rotation axis X can flow into the oil shield 15.

[0228] In addition, if Figure 12 As shown, the outer peripheral position of the rotation track of the second shaft portion 446 of the pinion shaft 44 and the outer peripheral position of the rotation track of the large-diameter gear portion 431 are offset in the radial direction of the rotation axis X. The outer peripheral position of the rotation track of the second shaft portion 446 is located on the inner diameter side of the outer peripheral position of the rotation track of the large-diameter gear portion 431.

[0229] Therefore, there is a margin in space on the outer diameter side of the second shaft portion 446. By utilizing this space to provide the oil-repellent portion 15, the space in the main body housing 10 can be effectively utilized.

[0230] like Figure 12 As shown, the second shaft portion 446 protrudes toward the rear of the small-diameter gear portion 432 when viewed from the motor 2. Components surrounding the second shaft portion 446 (e.g., the guide portion 78 of the differential case 50 supporting the second shaft portion 446) are located close to the oil shield portion 15.

[0231] Therefore, the oil OL (lubricating oil) can be smoothly supplied from the peripheral members to the oil guard portion 15 .

[0232] like Figure 8 As shown, an outer diameter end portion of an oil hole 151a is formed on the rear side of the support platform 151. The oil hole 151a extends radially inward within the fourth housing 14. The inner diameter end portion of the oil hole 151a is formed on the inner circumference of the support portion 145.

[0233] like Figure 2 As shown, in the support portion 145 , the inner diameter side end portion of the oil hole 151 a is opened between the lip seal RS and the bearing B2 .

[0234] like Figure 10 and Figure 12 As shown, an oil guide 152 is placed on the support platform 151 .

[0235] The oil guide 152 has a catch portion 153 and a portion extending from the catch portion 153 toward the first housing 11 ( Figure 10 A guide portion 154 extending from the front side of the paper (near the front side).

[0236] like Figure 12 As shown, when viewed from above, the support platform 151 is arranged at a position radially outside the rotation axis X and overlaps with a portion of the differential case 50 (first housing portion 6, second housing portion 7) to avoid interference with the stepped pinion 43 (large diameter gear portion 431).

[0237] The catch portion 153 is provided at a position overlapping the second shaft portion 446 of the pinion shaft 44 as viewed in the radial direction of the rotation axis X. The guide portion 154 is provided at a position overlapping the first shaft portion 445 and the large-diameter gear portion 431 of the pinion shaft 44 .

[0238] Therefore, when the differential case 50 rotates about the rotation axis X, the oil OL stirred up by the differential case 50 moves toward the capture portion 153 and the guide portion 154 .

[0239] A wall portion 153 a extending in a direction (upward) away from the support base portion 151 is provided on the outer peripheral edge of the catch portion 153 . A portion of the oil OL stirred up by the differential case 50 rotating about the rotation axis X can be stored in the oil guide 152 .

[0240] On the deep side of the capture portion 153 ( Figure 10 A cutout portion 155 is provided in the wall portion 153a (on the depth side of the paper).

[0241] The cutout portion 155 is provided in a region facing the oil hole 151 a . A portion of the oil OL stored in the capture portion 153 is discharged from the cutout portion 155 toward the oil hole 151 a .

[0242] Guide portion 154 tilts downward as it moves away from catch portion 153. Wall portions 154a, 154a are provided on both sides of guide portion 154 in the width direction. Wall portions 154a, 154a are provided along the entire length of guide portion 154 in the longitudinal direction. Wall portions 154a, 154a are connected to wall portion 153a surrounding the outer periphery of catch portion 153.

[0243] Therefore, a portion of the oil OL stored in the capture portion 153 is also discharged to the guide portion 154 side.

[0244] like Figure 11 As shown, the guide portion 154 extends toward the second case 12 at a position that avoids interference with the differential case 50. The front end 154b of the guide portion 154 faces the oil hole 126a provided in the wall portion 120 of the second case 12 with a gap in the rotation axis X direction.

[0245] A boss portion 126 surrounding the oil hole 126a is provided on the outer periphery of the wall portion 120. One end of a pipe 127 is fitted into the boss portion 126 in the direction of the rotation axis X.

[0246] The pipe 127 passes through the outside of the second housing 12 and reaches the third housing 13. The other end of the pipe 127 is connected to the oil hole 136a (see Figure 2 ) connected.

[0247] A portion of the oil OL stirred up by the differential case 50 rotating about the rotation axis X reaches the oil catcher 15 . The oil OL is supplied to the internal space Sc of the connecting wall 136 through the guide portion 154 and the pipe 127 .

[0248] like Figure 2 As shown, a radial oil passage 137 communicating with the internal space Sc is provided in the third case 13 .

[0249] The radial oil passage 137 extends radially downward from the internal space Sc and communicates with an axial oil passage 138 provided in the joint 132 .

[0250] The axial oil passage 138 is connected to the oil reservoir 128 provided in the lower portion of the second case 12 via a communication hole 112 a provided in the joint 112 of the first case 11 .

[0251] The oil reservoir 128 penetrates the inner portion of the peripheral wall 121 in the direction of the rotation axis X. The oil reservoir 128 is connected to an oil storage portion OP provided in the gear chamber Sb of the fourth case 14 .

[0252] In the gear chamber Sb, the disk-shaped plate member 8 is provided in a direction perpendicular to the rotation axis X. As described above, the plate member 8 divides the gear chamber Sb in the fourth case 14 into the first gear chamber Sb1 on the differential case 50 side and the second gear chamber Sb2 on the motor 2 side.

[0253] A cooling chamber CR (second cooling housing) is provided in a lower portion of the gear chamber Sb of the fourth housing 14 so as to be adjacent to the gear chamber Sb.

[0254] Figure 13 It is an enlarged view of the lower portion of the fourth housing 14 and the surrounding area of ​​the cooling chamber CR.

[0255] Figure 14 From the side of the peripheral wall portion 141 of the fourth housing 14 ( Figure 2 (left side of the paper) Observe the diagram of the cooling chamber CR.

[0256] Figure 15 This is a diagram showing a state where the cover 9 of the cooling chamber CR is removed.

[0257] Figure 16 It is a diagram for explaining the flow of the coolant CL.

[0258] Figure 17 It is a diagram showing the structure of the cover portion 9.

[0259] Figure 18 It is a diagram for explaining the assembly of the spacer 94 to the cover 9 .

[0260] Figure 19 It is a diagram for explaining the flow of the coolant CL in the cooling chamber CR.

[0261] like Figure 13 As shown, the cooling chamber CR includes a cover 143 and a lid 9. Coolant CL is introduced into the cooling chamber CR. As described above, an oil reservoir OP is formed in the lower portion of the gear chamber Sb. The coolant CL introduced into the cooling chamber CR cools the oil OL stored in the oil reservoir OP.

[0262] The outer cover portion 143 is a wall portion that covers the outer peripheral surface of the support wall portion 146 via a gap. Figure 15 As shown, the cover portion 143 is formed in an arc shape along the cylindrical support wall portion 146 when viewed from the direction of the rotation axis X. The cover portion 143 can be formed integrally with the support wall portion 146 by, for example, casting.

[0263] like Figure 13 As shown, the outer cover portion 143 extends along the direction of the rotation axis X. A base end portion 143a of the outer cover portion 143, which is provided on one end side in the direction of the rotation axis X, is connected to the joint portion 142 at the lower portion of the fourth housing 14. A joint portion 143b for the cover portion 9, described later, is provided at the opposite end of the base end portion 143a.

[0264] The inner wall surface 143c of the outer cover portion 143 and the outer peripheral surface of the support wall portion 146 are opposed to each other via a gap. Figure 15 As shown, an arcuate internal space is defined between the outer cover 143 and the support wall 146 when viewed from the direction of the rotation axis X. This arcuate internal space constitutes the interior of the cooling chamber CR. Furthermore, the opening CRo of the cooling chamber CR is formed by the joint 143b of the outer cover 143 and the joint 146b of the support wall 146.

[0265] The cover 9 closes the opening CRo of the cooling chamber CR. Figure 14 As shown, the cover portion 9 is a plate-shaped member having an arc shape when viewed from the rotation axis X direction.

[0266] An inlet 92a and an outlet 92b are provided near one end 91a and the other end 91b of the cover 9 in the circumferential direction of the rotation axis X. The inlet 92a and the outlet 92b are holes that pass through the cover 9 in the direction of the rotation axis X, and a pipe PI is connected to each of the holes. Figure 13 As shown, the inlet port 92a of the cover portion 9 is connected to the outlet port 124b of the cooling passage CP via the pipe PI.

[0267] Coolant CL in cooling circuit CP (refer to Figure 2 ) flows through the interior of the cooling passage CP to cool the motor 2 and is then discharged from the outlet 124b of the cooling passage CP. The coolant CL is introduced into the cooling chamber CR from the inlet 92a of the cooling chamber CR through the pipe PI.

[0268] like Figure 16 As shown in FIG. 1 , the cooling liquid CL introduced into the cooling chamber CR flows inside the cooling chamber CR. Thus, the supporting wall portion 146 (see FIG. 1 ) of the cooling chamber CR is formed. Figure 15 ) cooling. By also using it as the gear chamber Sb (refer to Figure 13 ) is cooled, and the oil OL stored in the oil storage portion OP in the gear chamber Sb is cooled.

[0269] like Figure 16 As shown, the coolant CL flowing in the cooling chamber CR is discharged from the discharge port 92b. The discharged coolant CL is introduced into the inlet 124a of the cooling passage CP again through a pipe (not shown) provided inside the vehicle. Figure 2 ).

[0270] like Figure 13 As shown in FIG. 1 , the end surface 93 of the cover 9 faces the interior of the cooling chamber CR. A spacer 94 is mounted on the end surface 93 so as to protrude toward the interior of the cooling chamber CR. Figure 17As shown in FIG. 1 , the spacer 94 is an arc-shaped component similar to the cover 9. The spacer 94 is installed between the inlet 92a and the outlet 92b of the cover 9. Figure 13 As shown, the spacer 94 has a thickness in the radial direction of the rotation axis X. The cover 9 and the spacer 94 may be made of different materials. The cover 9 may be made of metal, for example, and the spacer 94 may be made of resin, for example.

[0271] like Figure 18 As shown, spacer 94 is provided with a protrusion 95 for attaching spacer 94 to lid 9. A hole 93a is provided on end surface 93 of lid 9, into which protrusion 95 is inserted. An annular groove 93b is formed on the inner circumference of hole 93a of lid 9. The number and location of holes 93a corresponding to protrusion 95 are not limited; multiple holes 93a may be provided to ensure stable attachment of spacer 94 to lid 9.

[0272] The protrusion 95 is formed with a slit 95a cut from the distal end toward the proximal end of the protrusion 95 along the axis Y. For example, four slits 95a can be formed in the circumferential direction around the axis Y at 90° intervals.

[0273] The protrusions 95, which are divided by slits 95a, each have hook portions 95b formed at their tips, protruding radially outward from the axis Y. Each hook portion 95b is sized to fit into annular groove 93b in hole 93a. The outer diameter of protrusion 95 is set to match the inner diameter of hole 93a. The outer diameter of a certain tip of hook portion 95b is set to be larger than the inner diameter of hole 93a.

[0274] When installing the cover 9, the protrusion 95 is pressed in one direction, that is, toward the bottom of the hole 93a. Figure 18 The movement of protrusion 95 is indicated by the double-dashed line. When the tip of protrusion 95 contacts hole 93a, it bends due to the compressive force from the outer periphery, shrinking the width of slit 95a. The shrinking of slit 95a reduces the outer diameter of the tip of hook 95b. When the diameter matches the inner diameter α of hole 93a, protrusion 95 is inserted into hole 93a. When the tip of protrusion 95 reaches annular groove 93b, hook 95b engages with the annular groove 93b, and slit 95a returns to its original width. This engages protrusion 95 with hole 93a, and spacer 94 is attached to cover 9.

[0275] Note that this mounting method is just an example, and the spacer 94 may be mounted to the cover 9 by other mounting methods such as bolt fixing.

[0276] like Figure 13As shown, the cooling chamber CR is formed so as to span the first gear chamber Sb1 and the second gear chamber Sb2 when viewed in the radial direction of the rotation axis X. The first gear chamber Sb1 is located on the opening CRo side, which is the front side (left side in the figure) of the cooling chamber CR. The second gear chamber Sb2 is located on the back side (right side in the figure) of the cooling chamber CR, away from the opening CRo.

[0277] When the cover 9 closes the opening CRo of the cooling chamber CR, the spacer 94 is located on the front side of the cooling chamber CR (left side in the figure). The spacer 94 has a thickness in the radial direction of the rotation axis X, and thus functions as a volume reducing portion that reduces the volume of the front side of the cooling chamber CR. Figure 19 As shown by the dashed line, without the spacer 94, the coolant CL flowing from the inlet 92a to the outlet 92b tends to stagnate near the front of the cooling chamber CR and is less likely to reach the rear end of the cooling chamber CR. On the other hand, when the spacer 94 is included as in the embodiment, the spacer 94 extends toward the front of the cooling chamber CR. As a result, as shown by the dashed line, the coolant CL is guided not only toward the front of the cooling chamber CR but also toward the rear end. In other words, the spacer 94 functions as a guide member that directs the coolant CL introduced from the inlet 92a toward the direction away from the opening CR0.

[0278] like Figure 13 As shown, in the first gear chamber Sb1, located in the upper portion near the front side (left side in the figure) of the cooling chamber CR, the oil OL is lifted by the differential case 50, resulting in intense circulation of the oil OL. On the other hand, in the second gear chamber Sb2, located in the upper portion near the back side (right side in the figure) of the cooling chamber CR, the oil OL circulates more smoothly. Therefore, by providing a spacer 94, the coolant CL is directed toward the back side of the cooling chamber CR, allowing the coolant CL to gradually cool the oil OL in the second gear chamber Sb2. This improves the overall cooling efficiency of the oil OL in the oil reservoir OP.

[0279] The power transmission device 1 of the embodiment may be provided in a so-called series hybrid vehicle or a range-extended vehicle.

[0280] Figure 20 Schematic diagram showing a series hybrid vehicle VH.

[0281] Figure 21 and Figure 22 It is a schematic diagram showing the arrangement relationship between the power transmission device 1 and the exhaust pipe 104 . Figure 21 This is a diagram showing the power transmission device 1 as viewed from above. Figure 22 This is a diagram of the power transmission device 1 as viewed from the rotation axis X direction.

[0282] like Figure 20As shown, the vehicle VH includes an engine 100 as an internal combustion engine. The engine 100 does not drive the drive shafts DA and DB but drives a generator 101 .

[0283] Electric power generated by a generator 101 driven by the engine 100 is supplied to the motor 2 via an inverter 102 or stored in a battery 103 .

[0284] like Figure 21 As shown, the vehicle VH is provided with an exhaust pipe 104 for discharging exhaust gas from the engine 100 to the outside of the vehicle VH. The exhaust pipe 104 becomes a heat source because the exhaust gas from the engine 100 passes through the exhaust pipe 104 and its temperature rises.

[0285] The main body case 10 of the power transmission device 1 is located on a route of the exhaust pipe 104 from the engine 100 to the outside of the vehicle VH. Therefore, the exhaust pipe 104 is provided with a bent portion 104a that bypasses the main body case 10.

[0286] The bent portion 104a of the exhaust pipe 104 is bent in a direction away from the first housing 11 housing the motor 2. Figure 22 As shown, the curved portion 104a is configured to surround the lower portion of the fourth housing 14. This configuration of the curved portion 104a allows the exhaust pipe 104, a heat source, to be kept away from the motor 2, which has a high cooling priority. Furthermore, the cooling chamber CR is located in the lower portion of the fourth housing 14. The oil OL within the gear chamber Sb in the upper portion of the fourth housing 14 can be protected by the cooling chamber CR from the heat of the exhaust pipe 104. As described above, the cooling chamber CR is formed in an arc shape and is provided so as to surround the cylindrical fourth housing 14. Therefore, the cooling chamber CR can appropriately protect the gear chamber Sb from the heat of the exhaust pipe 104.

[0287] like Figure 1 1 and 2 , the operation of the power transmission device 1 having the above-described structure will be described.

[0288] In the power transmission device 1 , a planetary reduction gear 4 , a differential mechanism 5 , and drive shafts DA and DB are provided along a transmission path of the output rotation of the motor 2 .

[0289] like Figure 2 As shown, when the motor 2 is driven and the rotor core 21 rotates about the rotation axis X, rotation is input to the sun gear 41 of the planetary reduction gear 4 via the motor shaft 20 that rotates integrally with the rotor core 21 .

[0290] like Figure 3 As shown, in the planetary reduction gear 4, the sun gear 41 serves as an input portion for the output rotation of the motor 2. The differential case 50 supporting the stepped pinion 43 serves as an output portion for the input rotation.

[0291] When the sun gear 41 rotates about the rotation axis X by the input rotation, the stepped pinion 43 (large diameter gear portion 431 , small diameter gear portion 432 ) rotates about the axis X1 by the rotation input from the sun gear 41 side.

[0292] Here, the small-diameter gear portion 432 of the stepped pinion 43 meshes with the ring gear 42 fixed to the inner periphery of the fourth case 14. Therefore, the stepped pinion 43 revolves around the rotation axis X while rotating around the axis X1.

[0293] Here, the outer diameter R2 of the small-diameter gear portion 432 of the stepped pinion 43 is smaller than the outer diameter R1 of the large-diameter gear portion 431 (see Figure 3 ).

[0294] As a result, the differential case 50 (the first case portion 6 and the second case portion 7 ) supporting the stepped pinion gear 43 rotates about the rotation axis X at a rotation speed lower than the rotation input from the motor 2 side.

[0295] Therefore, the rotation of the sun gear 41 input to the planetary reduction gear 4 is greatly reduced in speed by the stepped pinion 43. The reduced rotation is output to the differential case 50 (differential mechanism 5).

[0296] The differential case 50 rotates around the rotation axis X by the input rotation, and thereby the drive shafts DA and DB meshing with the pinion gear 52 in the differential case 50 rotate around the rotation axis X. As a result, the left and right drive wheels W and W (see FIG. 1 ) of the vehicle equipped with the power transmission device 1 are rotated. Figure 1 ) is rotated by the transmitted rotational driving force.

[0297] like Figure 2 As shown, an oil reservoir OP storing lubricating oil OL is formed inside the fourth case 14. The oil OL stored in the oil reservoir OP is lifted up by the differential case 50 rotating about the rotation axis X when the output rotation of the motor 2 is transmitted.

[0298] The stirred oil OL lubricates the meshing portions between the sun gear 41 and the large-diameter gear portion 431 , the meshing portions between the small-diameter gear portion 432 and the ring gear 42 , and the meshing portions between the pinion mating gear 52 and the side gears 54A, 54B.

[0299] like Figure 9 As shown, the differential case 50 rotates in the counterclockwise direction CCW around the rotation axis X when viewed from the third case 13 side.

[0300] An oil sparging portion 15 is provided above the fourth case 14. This portion is located downstream of the differential case 50 in the rotational direction. Most of the oil OL lifted by the differential case 50 flows into the oil sparging portion 15. The oil OL is then supplied to an oil guide 152 mounted on a support platform 151 within the oil sparging portion 15.

[0301] Thus, most of the oil OL lifted by the differential case 50 flows into the oil retaining portion 15. A portion of the oil OL falls due to gravity and returns to and is stored in the oil storage portion OP. Figure 13 As shown, a cooling chamber CR is provided below the oil reservoir OP, through which coolant CL flows. While the temperature of the oil OL lifted by the differential case 50 rises, the oil OL returning to the oil reservoir OP is cooled by heat exchange with the coolant CL. The cooled oil OL is then lifted again by the differential case 50 and used for lubrication.

[0302] The cooling fluid CL of the oil OL in the cooling oil reservoir OP is stored in the cooling passage CP (refer to Figure 2 ) and then introduced into the cooling chamber CR. Specifically, in the embodiment, the coolant CL used to cool the motor 2 is also used to cool the oil OL, eliminating the need to provide a new coolant CL for cooling the oil OL. Furthermore, in the embodiment, by cooling the motor 2, which has a higher cooling priority, before the oil OL, appropriate thermal management of the entire power transmission device 1 can be achieved.

[0303] As described above, the power transmission device 1 of the present embodiment has the following structure.

[0304] (1) The power transmission device 1 has:

[0305] Motor 2;

[0306] a planetary reduction gear 4 and a differential mechanism 5 (gear mechanism), which are connected downstream of the motor 2;

[0307] The fourth case 14 (case) houses the planetary reduction gear 4 , the differential mechanism 5 , and oil OL (lubricating oil).

[0308] A cooling passage CP (first cooling box) is formed on the outer periphery of the motor 2 , through which a coolant CL for cooling the motor 2 is introduced.

[0309] A cooling chamber CR (second cooling chamber) is formed on the outer periphery of the fourth housing 14 , and the cooling chamber CR is connected to the cooling path CP so that the coolant CL can flow therethrough.

[0310] A cooling path CP for introducing coolant CL is provided on the periphery of the motor 2, and a cooling chamber CR for introducing coolant CL for cooling the motor 2 is provided on the periphery of the fourth case 14 housing the planetary reduction gear 4. The power transmission device 1 of the embodiment has a structure in which the cooling path CP protects the motor 2 from external heat, while the cooling chamber CR protects the oil OL. This provides a structure that protects the power transmission device 1 from external heat.

[0311] In the embodiment, the cooling chamber CR is provided in contact with the support wall 146, which is the outer periphery of the fourth housing 14. However, any structure may be used as long as it can protect the fourth housing 14 from external heat. For example, the cooling chamber CR may be provided separately from the support wall 146.

[0312] (2) The cooling chamber CR and the cooling path CP are arranged separately.

[0313] The cooling path CP and the cooling chamber CR may be formed integrally on the outer periphery of the main body housing 10, but are formed separately in the embodiment. This increases the degree of freedom in designing the power transmission device 1.

[0314] (3) The cooling chamber CR is formed in the lower portion of the fourth housing 14 as a part of the fourth housing 14 .

[0315] The cooling chamber CR is formed as part of the fourth housing 14, which is the gear housing housing that houses the planetary reduction gear 4 and the differential mechanism 5. Thus, in addition to providing protection from external heat, the cooling chamber CR also has the added function of cooling the lubricating oil OL within the fourth housing 14. Furthermore, since the cooling chamber CR is formed in the lower portion of the fourth housing 14, it can directly cool the oil reservoir OP below the gear chamber Sb, thereby improving cooling efficiency.

[0316] (4) The cooling chamber CR is configured to have an arc shape when viewed from the rotation axis X direction (axial direction).

[0317] The cooling chamber CR can be formed so as to wrap around the cylindrical fourth housing 14, thereby suppressing an increase in the size of the device. In addition, the protection effect of the cooling chamber CR against external heat can be enhanced.

[0318] (5) The coolant CL discharged from the cooling passage CP is introduced into the cooling chamber CR.

[0319] By also using the coolant CL from motor 2 to cool the oil OL in gear chamber Sb, there's no need to prepare new coolant CL. Furthermore, after cooling motor 2, coolant CL cools the oil OL in gear chamber Sb. Thus, the power transmission device 1 of the embodiment prioritizes cooling motor 2, enabling optimal thermal management of the entire device.

[0320] (6) The vehicle VH of the embodiment includes a heat source such as the exhaust pipe 104 and the above-described power transmission device 1. The heat source is disposed on the cooling chamber CR side.

[0321] Priority is given to protecting the motor 2 from external heat, so the heat source is arranged away from the motor 2. Thus, the heat source is arranged near the gear chamber Sb side, but the gear chamber Sb can be protected from heat by the cooling chamber CR.

[0322] (7) The heat source is the exhaust pipe 104 connected to the engine 100 (internal combustion engine).

[0323] The exhaust pipe 104 has a curved portion 104 a (circumvented portion) that curves in a direction away from the motor 2 .

[0324] The curved portion 104a is arranged so as to surround the cooling chamber CR.

[0325] With this configuration, the exhaust pipe 104 can be arranged at a position that prioritizes thermal management of the motor 2 and the oil OL. Furthermore, by providing the bent portion 104a that bypasses the motor 2, the exhaust pipe 104 can be arranged compactly.

[0326] While the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified appropriately within the scope of the technical concept of the invention.

[0327] Description of Reference Numerals

[0328] 1: Power transmission device

[0329] 14: The fourth box (box)

[0330] 2: Motor

[0331] 4: Planetary reduction gear

[0332] 5: Differential mechanism

[0333] 100: Engine (internal combustion engine)

[0334] 104: Exhaust pipe (heat source)

[0335] 104a Bend (circumventing portion)

[0336] CL: Coolant

[0337] CP: Cooling circuit (first cooling box)

[0338] CR: Cooling chamber (second cooling box)

[0339] VH: Vehicle

[0340] X: Rotation axis (axis)

Claims

1. A vehicle comprising: motor; a gear mechanism connected downstream of the motor; a housing having a motor chamber for accommodating the motor and a gear chamber for accommodating the gear mechanism and lubricating oil; exhaust pipe, A first cooling box is formed on the outer periphery of the motor to introduce a cooling liquid to cool the motor. A second cooling box is formed on the outer periphery of the box, and the second cooling box is connected so that the coolant can flow between the second cooling box and the first cooling box. The motor chamber is arranged at a position farther from the exhaust pipe than the gear chamber. The exhaust pipe has a winding portion that winds away from the motor. The circuitous portion is configured to surround the gear chamber.

2. The vehicle according to claim 1, wherein The second cooling box is arranged separately from the first cooling box.

3. The vehicle according to claim 1 or 2, wherein: The second cooling box is formed as a part of the box at the lower part of the box.

4. The vehicle according to claim 1 or 2, wherein: The second cooling box is configured to have an arc shape when viewed from the axial direction.

5. The vehicle according to claim 1 or 2, wherein: The coolant discharged from the first cooling box is introduced into the second cooling box.

6. The vehicle according to claim 1 or 2, wherein: The detour portion is arranged to surround the second cooling box.

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