Power transmission

Abstract

[Problem] To reduce the air suction of an oil pump. [Solution] This power transmission device comprises: a motor; a gear mechanism connected downstream of the motor; a pump which suctions an oil through a pump inlet; and a box including a first chamber that accommodates the gear mechanism, and a second chamber in which the pump inlet is disposed.

Description

[Technical field]

[0001] The present invention relates to a power transmission device. [Background technology]

[0002] Patent Document 1 discloses a power transmission device for an electric vehicle. The power transmission device has a gear mechanism (planetary reduction gear and a differential mechanism). A strainer is disposed on the outer periphery (radially outer side) of the gear mechanism to filter the oil supplied to the gear mechanism and supply it to the oil pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-152320 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the gear mechanism rotates, the oil on the outer periphery of the gear mechanism is scooped up, which can reduce the amount of oil near the strainer's intake port. If the oil pump sucks in oil when the amount of oil near the intake port is reduced, air may be sucked in.

[0005] In power transmission devices, it is required to reduce air intake by oil pumps. [Means for solving the problem]

[0006] In one embodiment of the present invention, a power transmission device comprises: A motor; a gear mechanism connected downstream of the motor; A strainer having a body and a pump inlet connected to the body; a pump into which oil is drawn via the pump inlet; a box including a first chamber that houses the gear mechanism and has an oil reservoir, and a second chamber in which the pump inlet and the main body are disposed, When viewed in a radial direction, the second chamber is offset from the motor, When viewed from a radial direction, the main body overlaps with the first chamber via a support wall that surrounds an outer periphery of the gear mechanism, The support wall portion has an opening portion that communicates with the first chamber and the second chamber and faces the oil reservoir portion. 、 The support wall has a portion whose outer diameter decreases with increasing distance from the motor, and the main body has a portion that overlaps the portion of the support wall where the outer diameter decreases as viewed in the radial direction. . Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to reduce air intake by the oil pump. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a skeleton diagram of a power transmission device according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of the power transmission device. [Diagram 3] FIG. 3 is an enlarged view of the planetary reduction gear and its surroundings of the power transmission device. [Figure 4] FIG. 4 is an enlarged view of the differential mechanism and its surroundings in the power transmission device. [Diagram 5] FIG. 5 is an exploded perspective view of a differential mechanism of the power transmission device. [Figure 6] FIG. 6 is a diagram illustrating the oil catch portion. [Figure 7] FIG. 7 is a diagram illustrating the oil catch portion. [Figure 8] FIG. 8 is a diagram illustrating the oil catch portion. [Figure 9] FIG. 9 is a diagram illustrating the oil catch portion. [Figure 10] FIG. 10 is a diagram illustrating the oil catch portion. [Figure 11] FIG. 11 is a diagram illustrating the oil catch portion. [Figure 12] FIG. 12 is a diagram illustrating the plate member. [Figure 13] FIG. 13 is a diagram illustrating the plate member. [Figure 14] FIG. 14 is a view of the fourth box as seen from the motor side. [Figure 15] FIG. 15 is a view of the fourth box as seen from the motor side. [Figure 16] FIG. 16 is a diagram illustrating the park lock mechanism. [Figure 17] FIG. 17 is a diagram illustrating the park lock mechanism. [Figure 18] FIG. 18 is a diagram illustrating the park lock mechanism. [Figure 19] FIG. 19 is an enlarged view of the strainer chamber and its surroundings. [Figure 20] FIG. 20 is a diagram illustrating an example of the configuration of an oil pump according to the first modification. [Figure 21] FIG. 21 is a diagram illustrating an example of the configuration of an oil pump according to the first modification. [Figure 22] FIG. 22 is a diagram illustrating an example of the configuration of an oil pump according to the first modification. [Figure 23] FIG. 23 is a diagram showing a configuration of a strainer chamber according to the second modification. [Figure 24] FIG. 24 is a schematic diagram showing a layout of a strainer chamber according to the third modification. [Diagram 25] FIG. 25 is a schematic diagram showing a layout of a strainer chamber according to the third modification. [Figure 26] FIG. 26 is a schematic diagram showing a layout of a strainer chamber according to the third modification. [Figure 27] FIG. 27 is a schematic diagram showing a layout of a strainer chamber according to the third modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a power transmission device according to an embodiment of the present invention will be described. In the following description, when a second element (part, section, etc.) connected to a first element (part, section, etc.), a second element (part, section, etc.) connected downstream of a first element (part, section, etc.), or a second element (part, section, etc.) connected upstream of a first element (part, section, etc.) is mentioned, it means that the first element and the second element are connected so as to be capable of transmitting power. The power input side is the upstream side, and the power output side is the downstream side. In addition, the first element and the second element may be connected via another element (clutch, other gear mechanism, etc.).

[0010] "Overlapping when viewed from a predetermined direction" means that a plurality of 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 travel direction (the vehicle forward direction, the vehicle backward direction), etc. When a drawing shows multiple elements (parts, portions, etc.) arranged in a specified direction, it may be assumed that the description in the specification contains a sentence explaining that they overlap when viewed from the specified direction.

[0011] "Not overlapping when viewed from a predetermined direction" and "offset when viewed from 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 reverse direction). When a drawing shows that multiple elements (parts, portions, etc.) are not lined up in a specified direction, it may be assumed that the description in the specification contains a sentence explaining that they do not overlap when viewed from a specified direction.

[0012] "When viewed from a predetermined direction, a first element (part, section, etc.) is located between a second element (part, section, etc.) and a third element (part, section, etc.)" means that the first element can be observed to be between the second element and the third element when observed from a predetermined direction. The "predetermined direction" refers to the axial direction, radial direction, gravity direction, vehicle running direction (vehicle forward direction, vehicle backward direction), etc. For example, when the second element, the first element, and the third element are arranged in that order along the axial direction, it can be said that the first element is located between the second element and the third element when viewed from the radial direction. When the drawing shows that the first element is between the second element and the third element when viewed from a predetermined direction, it may be deemed that the description in the specification contains a sentence explaining that the first element is between the second element and the third element when viewed from the predetermined direction.

[0013] When two elements (parts, sections, etc.) overlap when viewed in an axial direction, the two elements are coaxial.

[0014] "Axial direction" refers to the axial direction of the rotation shaft of a component constituting the power transmission device. "Radial direction" refers to the direction perpendicular to the rotation shaft of a component constituting the power transmission device. The component is, for example, a motor, a gear mechanism, a differential gear mechanism, etc.

[0015] FIG. 1 is a skeleton diagram illustrating a power transmission device 1 according to this embodiment. FIG. 2 is a schematic cross-sectional view illustrating the power transmission device 1 according to this embodiment. FIG. 3 is an enlarged view of the planetary reduction gear 4 and its surroundings of the power transmission device 1. As shown in FIG. FIG. 4 is an enlarged view of the differential mechanism 5 and its surroundings of the power transmission device 1. As shown in FIG.

[0016] As shown in FIG. 1, the power transmission device 1 includes a motor 2, a planetary reduction gear 4 (reduction mechanism) that reduces the output rotation of the motor 2 and inputs it to a differential mechanism 5 (differential gear), drive shafts DA and DB, and a park lock mechanism 3. In the power transmission device 1, a park lock mechanism 3, a planetary reduction gear 4, a differential mechanism 5, and drive shafts DA and DB (drive shafts) are provided along a transmission path of the output rotation about the rotation axis X of the motor 2. The planetary reduction gear 4 and the differential mechanism 5 are gear mechanisms.

[0017] In the power transmission device 1, the output rotation of the motor 2 is reduced by a planetary reduction gear 4 and input to a differential mechanism 5, and then transmitted via drive shafts DA, DB to the left and right drive wheels W, W of the vehicle on which the power transmission device 1 is mounted. Here, the planetary reduction gear 4 is connected downstream of the motor 2, the differential mechanism 5 is connected downstream of the planetary reduction gear 4, and the drive shafts DA, DB are connected downstream of the differential mechanism 5.

[0018] 2, the main box 10 (box) of the power transmission device 1 has a first box 11 that houses the motor 2, and a second box 12 that is extrapolated to the first box 11. The main box 10 has a third box 13 that is assembled to the first box 11, and a fourth box 14 that is assembled to the second box 12.

[0019] The first box 11 has a cylindrical support wall portion 111 and a flange-shaped joint portion 112 provided on one end 111 a of the support wall portion 111 . The first box 11 is provided with a support wall portion 111 oriented along the rotation axis X of the motor 2, and the motor 2 is housed inside the support wall portion 111.

[0020] The joint portion 112 is provided in a direction perpendicular to the rotation axis X, and is formed with an outer diameter larger than that of the support wall portion 111.

[0021] The second box 12 has a cylindrical peripheral wall portion 121, a flange-like joint portion 122 provided at one end 121a of the peripheral wall portion 121, and a flange-like joint portion 123 provided at the other end 121b of the peripheral wall portion 121. The peripheral wall portion 121 is formed with an inner diameter that allows it to be fitted onto the support wall portion 111 of the first box 11 . The first box 11 and the second box 12 are assembled to each other by fitting a peripheral wall portion 121 of the second box 12 onto a support wall portion 111 of the first box 11 .

[0022] A joint 122 on one end 121a side of the peripheral wall portion 121 abuts against a joint 112 of the first box 11 from the direction of the rotation axis X. These joints 122, 112 are connected to each other by a bolt (not shown). In the first box 11, a plurality of grooves 111b are provided on the outer periphery of the support wall portion 111. The plurality of grooves 111b are provided at intervals in the direction of the rotation axis X. Each of the grooves 111b is provided over the entire circumference in the circumferential direction around the rotation axis X. A peripheral wall portion 121 of the second box 12 is fitted onto the support wall portion 111 of the first box 11. The opening of the recessed groove 111b is closed by the peripheral wall portion 121. A plurality of cooling paths CP are formed between the support wall portion 111 and the peripheral wall portion 121, through which the coolant CL flows.

[0023] An inlet 124a for the coolant CL is provided on the joint 122 side of the peripheral wall 121, and an outlet 124b for the coolant CL is provided on the joint 123 side. The inlet 124a and the outlet 124b are holes that penetrate the peripheral wall 121 in the radial direction of the rotation axis X, and are each connected to a pipe (not shown) through which the coolant CL flows. The coolant CL is circulated through a pipe (not shown) arranged inside the vehicle by a water pump (not shown). The coolant CL is introduced from the inlet 124a into a cooling passage CP, and cools the oil OL in a motor chamber Sa, which will be described later.

[0024] Ring grooves 111c, 111c are formed on both sides of the region where the recessed groove 111b is provided on the outer periphery of the support wall portion 111 of the first box 11. Seal rings 113, 113 are fitted and attached to the ring grooves 111c, 111c. These seal rings 113 are pressed against the inner periphery of a peripheral wall portion 121 fitted onto 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 .

[0025] The other end 121b of the second box 12 is provided with a beam portion 120 extending from the joint portion 123 toward the inner diameter side. The beam portion 120 is provided in a direction perpendicular to the rotation axis X. An opening 120a through which the drive shaft DA is inserted is provided in a region of the beam portion 120 intersecting with the rotation axis X. A cylindrical motor support portion 125 surrounding the opening 120a is provided on the surface of the beam portion 120 facing the motor 2 (the right side in the figure).

[0026] The motor support portion 125 is inserted into the inside of a coil end 253b (described later). The motor support portion 125 faces an end portion 21b of the rotor core 21 with a gap in the direction of the rotation axis X. A bearing B1 is supported on the inner periphery of the motor support part 125. The outer periphery of the motor shaft 20 is supported by the motor support part 125 via the bearing B1.

[0027] A plurality of openings 120b extending in the radial direction of the rotation axis X are formed between the motor support portion 125 and the joint portion 123. The plurality of openings 120b are provided at intervals in the circumferential direction of the rotation axis X. The interiors of the second box 12 and the fourth box 14 are in communication with each other via the openings 120b.

[0028] 2, the vertical direction based on the state in which the power transmission device 1 is mounted on a vehicle is illustrated along the up-down direction of the figure. The peripheral wall portion 121 of the second box 12 has a radial thickness in a lower region in the vertical direction that is thicker than that in an upper region. An oil reservoir 128 is provided in this radially thick region so as to penetrate in the direction of the rotation axis X. The oil reservoir 128 is connected to an axial oil passage 138 provided in a joint 132 of the third box 13 via a communication hole 112 a provided in the joint 112 of the first box 11 .

[0029] The third box 13 has a wall portion 130 perpendicular to the rotation axis X. On the outer periphery of the wall portion 130, a joint portion 132 having a ring shape when viewed from the direction of the rotation axis X is provided. When viewed from the first box 11, the third box 13 is located on the opposite side to the differential mechanism 5 (on the right side in the figure). A joint 132 of the third box 13 is joined to a joint 112 of the first box 11 from the direction of the rotation axis X. The third box 13 and the first box 11 are connected to each other with bolts (not shown). In this state, the opening of the support wall 111 on the joint 122 side (on the right side in the figure) of the first box 11 is blocked by the third box 13.

[0030] In the third box 13, a wall portion 130 has a through hole 130a in the center thereof for receiving the drive shaft DA. A lip seal RS is provided on the inner periphery of the insertion hole 130a. The lip seal RS has a lip portion (not shown) that resiliently contacts the outer periphery of the drive shaft DA. The gap between the inner periphery of the insertion hole 130a and the outer periphery of the drive shaft DA is sealed by the lip seal RS. A peripheral wall portion 131 surrounding the insertion hole 130a is provided on the surface of the wall portion 130 facing the first box 11 (on the 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.

[0031] A motor support portion 135 is provided on the motor 2 side (left side in the figure) as viewed from the peripheral wall portion 131. The motor support portion 135 has a cylindrical shape that surrounds the rotation axis X with a gap therebetween. A cylindrical connecting wall 136 is connected to the outer periphery of the motor support portion 135. The connecting wall 136 is formed with an outer diameter larger than that of the peripheral wall portion 131 on the wall portion 130 side (the right side in the figure). The connecting wall 136 is provided in a direction along the rotation axis X and extends in a direction away from the motor 2. The connecting wall 136 connects the motor support portion 135 and the wall portion 130 of the third box 13.

[0032] The motor support portion 135 is supported by the third box 13 via a connection wall 136. One end 20a of the motor shaft 20 penetrates the inside of the motor support portion 135 from the motor 2 side to the peripheral wall portion 131 side. A bearing B1 is supported on the inner periphery of the motor support part 135. The outer periphery of the motor shaft 20 is supported by the motor support part 135 via the bearing B1.

[0033] An opening 136a is provided in the connecting wall 136. A space surrounded by the connecting wall 136 (an internal space Sc) communicates with a motor chamber Sa, which will be described later, via this opening 136a.

[0034] The fourth box 14 has a peripheral wall portion 141 that surrounds 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 box 12 side. The fourth box 14 is located on the differential mechanism 5 side (left side in the figure) when viewed from the second box 12. A joint 142 of the fourth box 14 is joined to a joint 123 of the second box 12 from the direction of the rotation axis X. The fourth box 14 and the second box 12 are connected to each other with bolts (not shown).

[0035] Inside a main body box 10 of the power transmission device 1, a motor chamber Sa that houses the motor 2, and a gear chamber Sb (first chamber) that houses the planetary reduction gear 4 and the differential mechanism 5 are formed. The motor chamber Sa is formed within the first box 11 between the beam portion 120 of the second box 12 and the wall portion 130 of the third box 13 .

[0036] The gear chamber Sb is formed between the beam portion 120 of the second box 12 in the fourth box 14 and the peripheral wall portion 141 of the fourth box 14. The motor chamber Sa and the gear chamber Sb communicate with each other through an opening 120b of the beam portion 120. Oil OL for lubricating the motor 2, the planetary reduction gear 4, the differential mechanism 5, etc. is sealed inside the main body box 10. As shown by the thick line in FIG. 2, an oil reservoir portion OP for storing the oil OL is formed in the motor chamber Sa and the gear chamber Sb. The oil OL in the oil reservoir portion OP can also flow into the above-mentioned internal space Sc through the opening 136a.

[0037] A plate member 8 (plate) is provided inside the gear chamber Sb. The plate member 8 is fixed to the fourth box 14 by bolts B. The plate member 8 divides the gear chamber Sb into a first gear chamber Sb1 that houses the planetary reduction gear 4 and the differential mechanism 5, and a second gear chamber Sb2 that houses the park lock mechanism 3. 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. The second gear chamber Sb2 communicates with the motor chamber Sa via an opening 120b of the beam portion 120.

[0038] The motor 2 has a motor shaft 20, a rotor core 21 (rotor), and a stator core 25 (stator). The motor shaft 20 is cylindrical. The drive shaft DA is disposed penetrating the inner circumference of the motor shaft 20. The rotor core 21 is cylindrical and is extrapolated onto the motor shaft 20. The stator core 25 surrounds the outer circumference of the rotor core 21 with a gap therebetween.

[0039] In the motor shaft 20, bearings B1, B1 are fitted onto and fixed to both sides of the rotor core 21. The bearing B1 located on one end 20a side (right side in the figure) of the motor shaft 20 when viewed from the rotor core 21 is supported on the inner periphery of the motor support part 135 of the third box 13. The bearing B1 located on the other end 20b side is supported on the inner periphery of the cylindrical motor support part 125 of the second box 12.

[0040] The motor support portions 135, 125 are disposed on the inner diameter side of coil ends 253a, 253b (described later) at one end 21a and the other end 21b of the rotor core 21, facing each other with a gap in the direction of the rotation axis X.

[0041] The rotor core 21 is formed by laminating a plurality of silicon steel plates. Each of the silicon steel plates is fitted onto the motor shaft 20 in a state in which the relative rotation with respect to the motor shaft 20 is restricted. The silicon steel plate is ring-shaped when viewed from the direction of the rotation axis X of the motor shaft 20. On the outer periphery of the silicon steel plate, N-pole and S-pole magnets (not shown) are provided alternately in the circumferential direction around the rotation axis X.

[0042] The stator core 25 surrounding the outer periphery of the rotor core 21 is formed by laminating a plurality of electromagnetic steel plates. The stator core 25 is fixed to the inner periphery of the cylindrical support wall portion 111 of the first box 11. Each of the electromagnetic steel plates has a yoke portion 251, teeth portions 252, and a coil 253. Yoke portion 251 is ring-shaped, and is fixed to the inner periphery of support wall portion 111. Teeth portions 252 protrude from the inner periphery of yoke portion 251 towards rotor core 21.

[0043] In this embodiment, the coil 253 is formed by winding a wire (not shown) across the multiple teeth 252. A known copper wire or the like can be used for the wire forming the coil 253. The coil 253 may be configured with a distributed winding or a concentrated winding around each of the multiple teeth 252 protruding toward the rotor core 21.

[0044] In stator core 25, the length of coil 253 in the direction of rotation axis X is set to be longer than that of rotor core 21. In stator core 25, coil ends 253a, 253b located at both ends of coil 253 in the direction of rotation axis X each protrude in the direction of rotation axis X beyond rotor core 21. Coil ends 253a, 253b are symmetrical with respect to teeth portion 252.

[0045] The other end 20b of the motor shaft 20 passes through an opening 120a provided in a beam portion 120 (motor support portion 125) of the second box 12 to the differential mechanism 5 side (left side in the figure) and is located inside the fourth box 14. The other end 20b of the motor shaft 20 faces a side gear 54A (described later) inside the fourth box 14 with a gap in the direction of the rotation axis X therebetween.

[0046] 3, the motor shaft 20 has a step portion 201 in a region located inside the fourth box 14. The region of the motor shaft 20 from the step portion 201 to the vicinity of the other end 20b forms a fitting portion 202 having a spline provided on the outer periphery. The park gear 30 of the parking lock mechanism 3 and the sun gear 41 are spline-fitted to the outer periphery of the fitting portion 202 .

[0047] One side surface of the park gear 30 in the direction of the rotation axis X abuts against the step portion 201. One end 410a of a cylindrical base portion 410 of the sun gear 41 abuts against the other side surface of the park gear 30 in the direction of the rotation axis X. A nut N that is screwed onto the other end 20b of the motor shaft 20 is in pressure contact with the other end 410b of the base portion 410 from the direction of the rotation axis X. The sun gear 41 and the park gear 30 are sandwiched between the nut N and the step portion 201 and are arranged so as to be unable to rotate relative to the motor shaft 20.

[0048] The sun gear 41 has a toothed portion 411 on the outer periphery on the other end 20b side of the motor shaft 20. A large diameter gear portion 431 of the stepped pinion gear 43 meshes with the outer periphery of the toothed portion 411.

[0049] The stepped pinion gear 43 has a large diameter gear portion 431 that meshes with the sun gear 41 and a small diameter gear portion 432 that has a smaller diameter than the large diameter gear portion 431. The stepped pinion gear 43 is a gear component in which a large diameter gear portion 431 and a small diameter gear portion 432 are arranged side by side in the direction of an axis X1 parallel to the rotation axis X and integrally provided. The large diameter gear portion 431 is formed with an outer diameter R 1 that is larger than an outer diameter R 2 of the small diameter gear portion 432 . The stepped pinion gear 43 is provided in a direction along the axis X1. A large diameter gear portion 431 of the stepped pinion gear 43 is located on the motor 2 side (on the right side in the figure).

[0050] 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 in the shape of a ring surrounding the rotation axis X at a distance. A plurality of engagement teeth 421 that protrude radially outward is provided on the outer periphery of the ring gear 42. The plurality of engagement teeth 421 are provided at intervals in the circumferential direction around the rotation axis X. Engagement teeth 421 provided on the outer periphery of the ring gear 42 are spline-fitted with teeth 146a provided on the support wall portion 146 of the fourth box 14. The rotation of the ring gear 42 around the rotation axis X is restricted.

[0051] The stepped pinion gear 43 has a through hole 430 passing through the inner diameter sides of the large diameter gear portion 431 and the small diameter gear portion 432 in the direction of the axis X1. The stepped pinion gear 43 is rotatably supported via needle bearings NB, NB on the outer periphery of a pinion shaft 44 which passes through a through hole 430.

[0052] 4, an in-shaft oil passage 440 is provided inside the pinion shaft 44. The in-shaft oil passage 440 penetrates the pinion shaft 44 from one end 44a to the other end 44b along the axis X1. The pinion shaft 44 is provided with oil holes 442 and 443 that connect the in-shaft oil passage 440 with the outer periphery of the pinion shaft 44 .

[0053] Furthermore, the pinion shaft 44 is provided with an introduction passage 441 for introducing the oil OL into the in-shaft oil passage 440 . The introduction passage 441 communicates with an internal case oil passage 781 formed in the base portion 71 of the second case portion 7, which will be described later.

[0054] Oil OL scooped up by the differential case 50, which will be described later, flows into the intra-case oil passage 781. The oil OL moving to the outer diameter side by centrifugal force caused by the rotation of the differential case 50 flows into the intra-case oil passage 781. The oil OL that flows from the in-case oil passage 781 into the introduction passage 441 flows into the in-shaft oil passage 440 of the pinion shaft 44. The oil OL that flows into the in-shaft oil passage 440 is discharged radially outward from the oil holes 442, 443. The oil OL discharged from the oil holes 442, 443 lubricates the needle bearing NB that is fitted onto the pinion shaft 44.

[0055] The pinion shaft 44 is provided with a through hole 444 on the other end 44b side from the region where the introduction passage 441 is provided. The through hole 444 passes through the pinion shaft 44 in the diameter direction. The pinion shaft 44 is provided so that its phase about the axis X1 is aligned with that of the through hole 444 and an insertion hole 782 on the second case part 7 side, which will be described later. The positioning pin P inserted into the insertion hole 782 passes through the through hole 444 of the pinion shaft 44. As a result, the pinion shaft 44 is supported on the second case part 7 side with its rotation about the axis X1 restricted.

[0056] 4, at one end 44a side in the longitudinal direction of the pinion shaft 44, an area protruding from the stepped pinion gear 43 constitutes 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. At the other end 44b side in the longitudinal direction of the pinion shaft 44, a region protruding from the stepped pinion gear 43 constitutes 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.

[0057] Here, the first shaft portion 445 refers to a region of the pinion shaft 44 on one end 44a side where the stepped pinion gear 43 is not fitted. The second shaft portion 446 refers to a region of the pinion shaft 44 on the other end 44b side where the stepped pinion gear 43 is not fitted. The length of the second shaft portion 446 of the pinion shaft 44 in the direction of the axis X1 is longer than the length of the first shaft portion 445 in the direction of the axis X1.

[0058] The main configuration of the differential mechanism 5 will now be described. FIG. 5 is an exploded perspective view of the differential mechanism 5. 4 and 5, the differential case 50 of the differential mechanism 5 is formed by assembling a first case portion 6 and a 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 function as a carrier that supports the pinion shaft 44 of the planetary reduction gear 4.

[0059] Between the first case portion 6 and the second case portion 7 of the differential case 50, three pinion mate gears 52 and three pinion mate shafts 51 are provided. The pinion mate shafts 51 function as support shafts that support the pinion mate gears 52. The pinion mate shafts 51 are provided at equal intervals in the circumferential direction about the rotation axis X. The inner diameter side ends of the pinion mate shafts 51 are connected to each other by a common connecting portion 510.

[0060] The pinion mate gears 52 are fitted onto the respective pinion mate shafts 51. Each of the pinion mate gears 52 is in contact with a connecting portion 510 from the radially outer side of the rotation axis X. In this state, each of the pinion mate gears 52 is rotatably supported by the pinion mate shaft 51 .

[0061] 4, in the differential case 50, a side gear 54A is located on one side of a connecting portion 510 in the direction of the rotation axis X, and a side gear 54B is located on the other side. The side gear 54A is rotatably supported by the first case portion 6. The side gear 54B is rotatably supported by the second case portion 7. The side gear 54A meshes with the pinion mate gear 52 from one side in the direction of the rotation axis X. The side gear 54B meshes with the pinion mate gear 52 from the other side in the direction of the rotation axis X.

[0062] The first case portion 6 has a ring-shaped base portion 61. An opening 60 is provided in the center of the base portion 61. A cylindrical wall portion 611 surrounding the opening 60 is provided on the surface of the base portion 61 opposite to the second case portion 7 (the right side in the figure). The outer periphery of the cylindrical wall portion 611 is supported by the plate member 8 via a bearing B3.

[0063] As shown in FIG. 5, three connecting beams 62 extending toward the second case portion 7 are provided on the surface of the base 61 facing the second case portion 7. The connecting beams 62 are provided at equal intervals in the circumferential direction about the rotation axis X. The connecting beam 62 has a base portion 63 perpendicular to the base portion 61 and a connecting portion 64 wider than the base portion 63.

[0064] As shown in FIG. 4, a support groove 65 for supporting the pinion mate shaft 51 is provided on the tip surface of the connecting portion 64. An arcuate portion 641 is formed on the inner diameter side (rotation axis X side) of the connecting portion 64 so as to have a shape that fits along the outer periphery of the pinion mate gear 52 . The outer periphery of the pinion mate gear 52 is supported by the arc portion 641 .

[0065] In the connecting beam 62, a gear support portion 66 is connected to the boundary portion between the base portion 63 and the connecting portion 64. The gear support portion 66 is provided in a direction perpendicular to the rotation axis X. The gear support portion 66 has a through hole 660 in the center. This through hole 660 is extrapolated to the cylindrical wall 541 of the side gear 54A.

[0066] A support hole 61a is provided in the base portion 61. One end 44a of the pinion shaft 44 is fitted into the support hole 61a.

[0067] The second case portion 7 has a ring-shaped base portion 71 . A through hole 70 is provided in the center of the base 71, penetrating the base 71 in the thickness direction. A cylindrical wall portion 72 surrounding the through hole 70 and a peripheral wall portion 73 surrounding the cylindrical wall portion 72 with a gap therebetween are provided on the surface of the base portion 71 opposite to the first case portion 6 (the left side in the figure).

[0068] A slit 710 is provided on the inner diameter side of the peripheral wall portion 73, penetrating the base portion 71 in the thickness direction. A protruding wall 711 is provided between adjacent slits 710, 710 in the circumferential direction around the rotation axis. The protruding wall 711 extends linearly in the radial direction of the rotation axis X. The protruding wall 711 is provided straddling the peripheral wall portion 73 on the outer diameter side and the cylindrical wall portion 72 on the inner diameter side.

[0069] On the outer diameter side of the peripheral wall portion 73, between the support holes 71a, 71a adjacent to each other in the circumferential direction around the rotation axis X, bolt accommodating portions 76, 76 recessed toward the rear of the page are provided. A bolt insertion hole 77 opens on the inside of the bolt accommodating portion 76. The insertion hole 77 penetrates the base portion 71 in the thickness direction (the direction of the rotation axis X).

[0070] A connecting portion 74 that protrudes towards the first case portion 6 is provided on the surface of the base portion 71 facing the first case portion 6 (the right side in the figure). 4, a support groove 75 for supporting the pinion mate shaft 51 is provided on the tip surface of the connecting portion 74. An arc portion 741 that follows the outer periphery of the pinion mate gear 52 is provided on the inner diameter side (rotation axis X side) of the connecting portion 74. The arc portion 741 supports the outer periphery of the pinion mate gear 52.

[0071] 5, a cylindrical tube wall portion 540 is provided on the back surface of the side gear 54B. A washer 55 is fitted onto the tube wall portion 540. A guide portion 78 is provided on the base portion 71 of the second case portion 7, protruding toward the first case portion 6 side (the right side in the figure).

[0072] As shown in FIG. 4, in a cross-sectional view along the axis X1, the pinion shaft 44 is inserted into the support hole 71a of the guide portion 78 from the first case portion 6 side.

[0073] In the differential case 50, a bearing B2 is fitted onto the cylindrical wall portion 72 of the second case portion 7. The bearing B2 fitted onto the cylindrical wall portion 72 is held by a support portion 145 of the fourth box 14, and the cylindrical wall portion 72 of the differential case 50 is rotatably supported by the fourth box 14 via the bearing B2.

[0074] The drive shaft DB, which passes through an opening 145a of the fourth box 14, is inserted into the support portion 145 from the direction of the rotation axis X. The drive shaft DB is supported by the support portion 145 so as to be rotatable. A lip seal RS is fixed to the inner periphery of the opening 145a. A lip portion (not shown) of the lip seal RS is in elastic contact with the outer periphery of a cylindrical wall portion 540 of a side gear 54B that is fitted onto the drive shaft DB. This seals the gap between the outer periphery of the cylindrical wall portion 540 of the side gear 54B and the inner periphery of the opening 145a.

[0075] The first case portion 6 of the differential case 50 is supported by a plate member 8 via a bearing B3 that is fitted onto the cylindrical wall portion 611. As shown in FIG. 2, inside the first case portion 6, the drive shaft DA passing through the insertion hole 130a of the third box 13 is inserted from the rotation axis direction. The drive shaft DA is provided across 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.

[0076] 4, side gears 54A, 54B are spline-fitted to the outer periphery of the tip end of the drive shafts DA, DB inside the differential case 50. The side gears 54A, 54B and the drive shafts DA, DB are connected to be able to rotate integrally around the rotation axis X.

[0077] In this state, the side gears 54A, 54B are disposed facing each other with a gap therebetween in the direction of the rotation axis X. A connecting portion 510 of the pinion mate shaft 51 is positioned between the side gears 54A, 54B. 5, the pinion mate gears 52 are supported by the pinion mate shafts 51. The pinion mate gears 52 are assembled to a side gear 54A located on one side in the direction of the rotation axis X and a side gear 54B located on the other side in a state in which their teeth mesh with each other.

[0078] As shown in FIG. 2, when the power transmission device 1 is mounted on a vehicle, the lower side of the differential case 50 is located within an oil reservoir OP.

[0079] In this embodiment, when the connecting beam 62 is positioned at the lowest side, the oil OL is stored up to a height at which the connecting beam 62 is located within the oil reservoir OP. 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.

[0080] 6 to 11 are diagrams illustrating the oil catch portion 15. FIG. FIG. 6 is a plan view of the fourth box 14 as viewed from the third box 13 side. FIG. 7 is a perspective view of the oil catch portion 15 shown in FIG. 6, seen obliquely from above. Fig. 8 is a plan view of the fourth box 14 as viewed from the third box 13 side. Fig. 8 shows a state in which the differential case 50 is disposed. Fig. 9 is a perspective view of the oil catch portion 15 shown in Fig. 8 as viewed obliquely from above. FIG. 10 is a schematic diagram of a cross section taken along line AA in FIG. FIG. 11 is a schematic diagram illustrating the positional relationship between the oil catch portion 15 and the differential case 50 (the first case portion 6, the second case portion 7) when the power transmission device 1 is viewed from above. 6 and 8, the joint portion 142 and the support wall portion 146 of the fourth box 14 are shown with hatching to clarify the positions thereof. Also, the plate member 8 is not shown in FIGS. 6 and 8.

[0081] 6, the fourth box 14 is provided with a support wall portion 146 surrounding a central opening 145a with a gap therebetween when viewed from the direction of the rotation axis X. The inside of the support wall portion 146 (the rotation axis X) forms an accommodation portion 140 for the differential case 50. At the upper part inside the fourth box 14, a space for an oil catch portion 15 and a space for a breather chamber 16 are formed.

[0082] A communication port 147 is provided in a region of the support wall portion 146 of the fourth box 14 that intersects with the vertical line VL. The communication port 147 connects the oil catch portion 15 and the accommodation portion 140 of the differential case 50 to each other.

[0083] The oil catch portion 15 and the breather chamber 16 are located on one side (the left side in the figure) and the other side (the right side in the figure) of a vertical line VL that is perpendicular to the rotation axis X, respectively. The oil catch portion 15 is disposed at a position offset from a vertical line VL passing through the rotation center (rotation axis X) of the differential case 50. When viewed from above, the oil catch portion 15 is disposed at a position offset from directly above the differential case 50. Here, the vertical line VL is a vertical line VL based on the installation state of the power transmission device 1 on the vehicle. When viewed from the direction of the rotation axis X, the vertical line VL is perpendicular to the rotation axis X. In the following description, the horizontal line HL is a horizontal line HL based on 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.

[0084] In FIG. 6, the oil catch portion 15 is formed so as to extend beyond the support wall portion 146 into the depth of the page. A support base 151 (shelf) is provided at the lower edge of the oil catch portion 15 so as to protrude toward the front side of the page. The support base 151 is provided in a range that is closer to the front side of the page than the support wall portion 146 and is located beyond the joint portion 142 of the fourth box 14 toward the back side of the page.

[0085] When viewed from the direction of the rotation axis X, a communication port 147 is provided on the vertical line VL side (the right side in the figure) of the oil catch portion 15. The communication port 147 is formed by cutting out a part of the support wall portion 146. When viewed from the direction of the rotation axis X, the communication port 147 is provided in a range that crosses the vertical line VL from the breather chamber 16 side (right side in the figure) to the oil catch portion 15 side (left side in the figure).

[0086] As shown in FIG. 8, 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 about the rotation axis X as viewed from the third box 13 side. Therefore, the oil catch portion 15 is located downstream in the rotation direction of the differential case 50. The circumferential width of the communication port 147 is wider on the left side of the vertical line VL than on the right side. Here, the left side of the communication port 147 across the vertical line VL is the downstream side in the rotation direction of the differential case 50, and the right side is the upstream side. This allows most of the oil OL scooped up by the differential case 50 rotating around the rotation axis X to flow into the oil catch portion 15.

[0087] 11 , the outer circumferential position of the rotation orbit of the second shaft portion 446 of the pinion shaft 44 and the outer circumferential position of the rotation orbit of the large diameter gear portion 431 are offset in the radial direction of the rotation axis X. The outer circumferential position of the rotation orbit of the second shaft portion 446 is located on the inner diameter side of the outer circumferential position of the rotation orbit of the large diameter gear portion 431. Therefore, there is a space on the outer diameter side of the second shaft portion 446. The oil catch portion 15 is provided by utilizing this space, and the space inside the main body box 10 can be effectively utilized.

[0088] 11, the second shaft portion 446 protrudes to the rear side of the small diameter gear portion 432 when viewed from the motor 2. A peripheral member of the second shaft portion 446 (for example, the guide portion 78 of the differential case 50 that supports the second shaft portion 446) is located close to the oil catch portion 15. This allows the oil OL (lubricating oil) to be smoothly supplied to the oil catch portion 15 from the surrounding members.

[0089] 7, an outer diameter side end of the oil hole 151a opens at the back side of the support base portion 151. The oil hole 151a extends toward the inner diameter side within the fourth box 14. The inner diameter side end of the oil hole 151a opens to the inner periphery of the support portion 145. As shown in FIG. 4, an end portion on the inner diameter side of the oil hole 151a in the support portion 145 opens between the lip seal RS and the bearing B2.

[0090] As shown in FIGS. 8 and 11, an oil guide 152 is placed on the support base portion 151. The oil guide 152 has a catch portion 153 and a guide portion 154 extending from the catch portion 153 toward the first box 11 side (the front side of the paper in FIG. 8).

[0091] As shown in FIG. 11, when viewed from above, the support base portion 151 is provided radially outward of the rotation axis X at a position overlapping a portion of the differential case 50 (first case portion 6, second case portion 7) while avoiding interference with the stepped pinion gear 43 (large diameter gear portion 431). When viewed from the radial direction of the rotation axis X, the catch portion 153 is provided at a position overlapping with the second shaft portion 446 of the pinion shaft 44. Furthermore, the guide portion 154 is provided at a position overlapping with the first shaft portion 445 of the pinion shaft 44 and the large diameter gear portion 431.

[0092] Therefore, when the differential case 50 rotates around the rotation axis X, a portion of the oil OL scooped up by the differential case 50 moves towards the catch portion 153 and the guide portion 154.

[0093] A wall portion 153a is provided on the outer circumferential edge of the catch portion 153, extending in a direction (upward) away from the support base portion 151. A part of the oil OL scooped up by the differential case 50 rotating about the rotation axis X is stored in the oil guide 152.

[0094] At the rear side of the catch portion 153 (the rear side of the paper surface in FIG. 9), a notch 155 is provided in the wall portion 153a. The notch 155 is provided in a region facing the oil hole 151a. A part of the oil OL stored in the catch portion 153 is discharged from the notch 155 toward the oil hole 151a.

[0095] Guide portion 154 is inclined downward as it moves away from catch portion 153. Wall portions 154a, 154a are provided on both sides in the width direction of guide portion 154. Wall portions 154a, 154a are provided over the entire length of guide portion 154 in the longitudinal direction. Wall portions 154a, 154a are connected to wall portion 153a that surrounds the outer periphery of catch portion 153. A portion of the oil OL stored in the catch portion 153 is also discharged to the guide portion 154 side.

[0096] As shown in Fig. 10, the guide portion 154 extends toward the second box 12 at a position that avoids interference with the differential case 50 (see Fig. 2). A tip 154b of the guide portion 154 is located above the parking lock mechanism 3 (see Fig. 2). As shown by the arrow in Fig. 10, the oil OL that reaches the tip 154b of the guide portion 154 drops downward and is supplied to the parking lock mechanism 3 (see Fig. 2).

[0097] 2, a radial oil passage 137 is provided between the joints 132 of the wall 130 of the third box 13. The radial oil passage 137 communicates with an axial oil passage 138 provided in the joint 132.

[0098] The axial oil passage 138 communicates with an oil reservoir 128 provided in the lower part of the second box 12 via a communication hole 112 a provided in the joint 112 of the first box 11 . The oil reservoir 128 penetrates the peripheral wall 121 in the direction of the rotation axis X, and communicates with the oil reservoirs OP of the motor chamber Sa and the gear chamber Sb.

[0099] 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 box 14 into the first gear chamber Sb1 on the differential case 50 side and the second gear chamber Sb2 on the motor 2 side.

[0100] 12 and 13 are diagrams illustrating the plate member 8. FIG. FIG. 12 is a plan view of the plate member 8 as viewed from the motor 2 side. FIG. 13 is a cross-sectional view taken along line AA in FIG. 13, the plate member 8 has a surface 80a and a surface 80b. The surface 80b (opposing surface) faces the planetary reduction gear 4 and the differential case 50 (see FIG. 2), which are the gear mechanism. The opposite surface 80a (rear surface) faces the motor 2 (see FIG. 2). 12, the plate member 8, as viewed from the motor 2 side, has a ring-shaped base 80. A ring-shaped support portion 801 surrounding a through hole 800 is provided in the center of the base 80.

[0101] As shown in FIG. 12, the base portion 80 has an outer peripheral edge 80c provided with connection pieces 81, 82, 83, and 84. Each of the connection pieces 81, 82, 83, and 84 extends radially outward from an outer circumferential edge 80c of the base portion 80. The connection pieces 81, 82, 83, and 84 are provided with bolt holes 81a, 82a, 83a, and 84a, respectively.

[0102] The connection piece 81 is provided at a position intersecting the vertical line VL on the upper portion of the plate member 8. The connection piece 81 extends in a direction away from the base portion 80 along the vertical line VL. On one side of the vertical line VL (the left side in FIG. 12), one connection piece 82 and one connection piece 83 are provided on the upper and lower sides of the horizontal line HL. These connection pieces 82 and 83 also extend in a direction away from the base 80.

[0103] On the other side of the vertical line VL (the right side in FIG. 12), a connection piece 84 is provided below the horizontal line HL. This connection piece 84 protrudes downward below the horizontal line HL from a position where it passes through the lower edge of the connection piece 83 and intersects with a straight line HLa that is parallel to the horizontal line HL.

[0104] On the other side of the vertical line VL (the right side in FIG. 12), a connection piece 85 is provided above the horizontal line HL. The connection piece 85 is provided in an arc shape having a width in the circumferential direction about the rotation axis X. A bolt hole 85a is provided in the connection piece 85 at a position closer to the vertical line VL. A support pin 85b is provided at a position closer to the horizontal line HL. The support pin 85b protrudes towards the front of the page.

[0105] A support boss 86 for a stopper pin 861 (see FIG. 17) is provided on a surface 80a (see FIG. 13) of the plate member 8 facing the motor 2. The support boss 86 is provided with a hole 86a (see FIG. 12) through which the stopper pin 861 is inserted. The support boss 86 is provided adjacent to the connection piece 81 below the connection piece 81 located on the vertical line VL.

[0106] 12, an attachment boss 87 is provided below the support boss 86. The attachment boss 87 passes through the support pin 85b and is provided at a position where it intersects with a straight line HLb that is parallel to the horizontal line HL. The attachment boss 87 protrudes further into the paper than the support boss 86. Furthermore, a mounting boss 88 that pairs with the mounting boss 87 is provided below the support pin 85b in the direction of the vertical line VL.

[0107] As viewed from the mounting boss 87, on the opposite side to the support pin 85b (the left side in the figure), a mounting portion 89 for a support 33, which will be described later, is provided. The mounting portion 89 has two bolt holes 89a, 89a arranged adjacent to each other in the horizontal direction.

[0108] FIG. 14 is a diagram of the fourth box 14 as viewed from the motor 2 side, illustrating the arrangement of steps 148d, 149d, and 17d that support the outer periphery of the plate member 8. As shown in FIG. In FIG. 14, the positions of the peripheral walls 148, 149, the arcuate wall 17, and the positions of the steps 148d, 149d, 17d are shown hatched in order to clarify them. FIG. 15 is a diagram of the fourth box 14 as viewed from the motor 2 side, illustrating a state in which the plate member 8 is attached.

[0109] 14, the fourth box 14 is provided with peripheral wall portions 148, 149 when viewed in the direction of the rotation axis X. The peripheral wall portions 148, 149 are provided on the outer diameter side of the region of the support wall portion 146 where the teeth portion 146a is provided. The peripheral walls 148 and 149 are formed in an arc shape with the rotation axis X as the center.

[0110] The peripheral wall portion 148 is located below the oil catch portion 15 in the direction of the vertical line VL. When viewed from the direction of the rotation axis X, the peripheral wall portion 148 is provided in a range that crosses a horizontal line HL passing through the rotation axis X from above to below. An upper end 148a of the peripheral wall portion 148 is located near the support base portion 151. A lower end 148b of the peripheral wall portion 148 is located near the straight line HLa.

[0111] When viewed from the direction of the rotation axis X, the inner periphery 148c of the peripheral wall portion 148 forms an arc shape that follows the outer periphery of the plate member 8 (base portion 80) described above. The inner diameter of the inner periphery 148c of the peripheral wall portion 148 is slightly larger than the outer diameter of the plate member 8. Here, the inner diameter of the inner periphery 148c and the outer diameter of the plate member 8 are based on the rotation axis X. The peripheral wall portion 148 is provided on its inner side with a step portion 148d recessed toward the back of the page. When the plate member 8 is attached to the fourth box 14, the outer circumferential edge of the plate member 8 (base portion 80) comes into contact with the step portion 148d from the direction of the rotation axis X.

[0112] A boss portion 18 having a bolt hole 18a is formed integrally with the peripheral wall portion 148 on the outer side of the peripheral wall portion 148. The boss portion 18 is provided near an upper end portion 148a and a lower end portion 148b of the peripheral wall portion 148. The boss portions 18, 18 protrude beyond the peripheral wall portion 148 to the front side of the page.

[0113] The peripheral wall portion 149 is located below the breather chamber 16. The peripheral wall portion 149 is located on the inner side of the drawing sheet relative to a wall portion 160 that defines the breather chamber 16. When viewed from the direction of the rotation axis X, an upper end 149a of the peripheral wall portion 149 is connected to the boss portion 18 on the vertical line VL. A side wall portion 159 extending toward the oil catch portion 15 is further connected to the boss portion 18. A lower end 149b of the peripheral wall portion 149 is connected to the peripheral wall portion 141 of the fourth box 14 below the breather chamber 16.

[0114] When viewed from the direction of the rotation axis X, the inner periphery 149c of the peripheral wall portion 149 forms an arc shape that follows the outer periphery of the plate member 8 (base portion 80) described above. The inner diameter of the inner periphery 149c of the peripheral wall portion 149 is slightly larger than the outer diameter of the plate member 8. Here, the inner diameter of the inner periphery 149c and the outer diameter of the plate member 8 are based on the rotation axis X. A step 149d recessed toward the rear of the page is provided on the inner side of the peripheral wall portion 149. When the plate member 8 is attached to the fourth box 14, the outer peripheral edge of the plate member 8 (base portion 80) abuts against the step 149d from the direction of the rotation axis X.

[0115] On the outer side of the peripheral wall portion 149, boss portions 18, 18 having bolt holes 18a are formed integrally with the peripheral wall portion 149. The boss portions 18, 18 are provided at intervals in the circumferential direction about the rotation axis X. The boss portions 18 are provided on the outer periphery of an upper end portion 148a of the peripheral wall portion 149 and on the outer periphery of a region located below the breather chamber 16. The boss portions 18, 18 protrude beyond the peripheral wall portion 149 toward the front side of the page.

[0116] In the fourth box 14, an arcuate wall portion 17 is provided in a region below the horizontal line HL below the breather chamber 16. The arcuate wall portion 17 is provided at a position that is shifted in phase by approximately 180° from the peripheral wall portion 148 in the circumferential direction about the rotation axis X. When viewed from the direction of the rotation axis X, the inner periphery 17c of the arc-shaped wall portion 17 forms an arc shape that follows the outer periphery of the plate member 8 (base portion 80) described above. The inner diameter of the inner periphery 17c of the arc-shaped wall portion 17 is slightly larger than the outer diameter of the plate member 8. Here, the inner diameter of the inner periphery 17c and the outer diameter of the plate member 8 are based on the rotation axis X. A boss portion 18 having a bolt hole 18a is formed at a position where the arc-shaped wall portion 17 intersects with the straight line HLa. The boss portion 18 protrudes further than the arc-shaped wall portion 17 toward the front side of the page.

[0117] The boss portion 18 is provided on its inner periphery with a step portion 17d that protrudes in the direction of the rotation axis X. When the plate member 8 is attached to the fourth box 14, the outer circumferential edge of the plate member 8 (base portion 80) comes into contact with the step portion 17d from the direction of the rotation axis X.

[0118] Here, the plate member 8 is attached to the fourth box 14 by first abutting the outer periphery of the plate member 8 (base portion 80) against the steps 148d, 149d of the peripheral walls 148, 149 and the step 17d of the arcuate wall portion 17 from the direction of the rotation axis X. Next, the bolts B passing through the bolt holes 81a-85a of the connection pieces 81-85 are screwed into the corresponding bolt holes 18a of the boss portion 18, thereby fixing the plate member 8 to the fourth box 14 (see FIG. 16).

[0119] Figures 16, 17 and 18 are diagrams for explaining the parking lock mechanism 3. Figure 16 is a perspective view of the fourth box 14 in which the parking lock mechanism 3 is provided, as seen from diagonally above. Figure 17 is a plan view of the fourth box 14 in which the parking lock mechanism 3 is provided, as seen from the motor 2 side. Figure 18 is a view of the parking lock mechanism 3 as seen from above.

[0120] As shown in FIG. 16, the parking lock mechanism 3 has a parking gear 30, a parking pole 31, a parking rod 32, a support 33, a holder 34, a manual plate 35, a detent spring 36, and a manual shaft 37. The park lock mechanism 3 is a park-by-wire type parking lock mechanism. When a sensor detects switching between driving mode and parking mode of the vehicle equipped with the power transmission device 1, the park lock mechanism 3 rotates the manual shaft 37 around the rotation axis Y (see FIG. 18) by the actuator ACT.

[0121] In this embodiment, a park gear 30, a park pole 31, a park rod 32, a support 33, and a holder 34 are located on the motor 2 side (the lower side in FIG. 18) of the plate member 8. A manual plate 35, a detent spring 36, and a manual shaft 37 are located on the opposite side.

[0122] The holder 34 is a plate-shaped member. The holder 34 has a protrusion 341 for supporting the park pole 31. As shown in Fig. 16 and Fig. 17, the park pole 31 is supported by the plate member 8 via the holder 34. The park pole 31 is an integral part having a first plate-shaped portion 310 having an insertion hole 310d and a second plate-shaped portion 311 having a claw portion 311c.

[0123] A protrusion 341 on the holder 34 side is inserted into the insertion hole 310d of the park pole 31. The park pole 31 is rotatably supported by the protrusion 341. In the rotation 310, the park pole 31 has an area beyond the bent part 310e extending along the straight line Lx2. The tip side of this area is an operated part 310c that is operated by the cam 320 of the park rod 32. The operated portion 310 c is placed on a cam 320 supported by a support 33 .

[0124] A claw portion 311c is provided on the lower portion of the second plate-shaped portion 311 when viewed from the direction of the rotation axis X. The claw portion 311c is an engagement portion with the park gear 30. The claw portion 311c is formed so as to bulge out from the lower portion of the second plate-shaped portion 311 toward the rotation axis X side.

[0125] A locking hole 310f is provided on the side of the insertion hole 310d in the first plate-shaped portion 310 of the park pole 31. One end of a spring Sp that is fitted onto the support pin 85b of the plate member 8 is engaged with the locking hole 310f. The park pole 31 is constantly biased by the biasing force of the spring Sp in a direction that moves the claw portion 311c away from the park gear 30 (counterclockwise in FIG. 17: see the arrow).

[0126] 3, the first plate-shaped portion 310 of the park pole 31 is disposed between the holder 34 and the plate member 8 in the direction of the rotation axis X. The second plate-shaped portion 311 is positioned closer to the motor 2 (to the right in the figure) than the first plate-shaped portion 310. The second plate-shaped portion 311 extends downward on the inner diameter side of the holder 34.

[0127] As shown in FIG. 17, when viewed from the direction of the rotation axis X, the park rod 32 is provided in a direction perpendicular to the rotation axis X and along a straight line Lx3 passing above the horizontal line HL. The parking rod 32 is provided such that the tip side where the cam 320 is inserted faces the park pole 31 side (the breather chamber 16 side). The cam 320 is inserted between the support 33 and the operated portion 310c of the park pole 31.

[0128] When the parking rod 32 is displaced in a direction (rightward in FIG. 18) in which the cam 320 is pushed between the support 33 and the operated portion 310c of the parking pole 31, the cam 320 pushes up the operated portion 310c. 17, the park pole 31 is rotated clockwise in FIG.

[0129] When the park rod 32 is displaced in a direction to pull out the cam 320 from between the support 33 and the operated portion 310c of the park pole 31 (to the left in FIG. 18), the park pole 31 rotates counterclockwise in FIG. 17 due to the biasing force of the spring Sp. The park pole 31 rotated counterclockwise is located at a disengaged position. The disengaged position is a position where the claw portion 311c is disengaged from the outer periphery of the park gear 30.

[0130] 18, the other end 32b of the parking rod 32 is supported by a connecting portion 355 of the manual plate 35. In this state, the parking rod 32 is provided so as to be displaceable in the axial direction while being prevented from falling off the connecting portion 355.

[0131] The manual plate 35 has a base portion 351, an arm portion 353, and an engagement portion 352. The base portion 351 is fitted onto the manual shaft 37. The arm portion 353 and the engagement portion 352 extend from the outer periphery of the base portion 351 in the radial direction of the rotation axis Y of the manual shaft 37.

[0132] The base portion 351 is fixed to the manual shaft 37 in a state in which relative rotation between the base portion 351 and the manual shaft 37 is restricted. The arm portion 353 extends from the outer periphery of the base portion 351 in a direction approaching the motor 2. When viewed in the radial direction of the rotation axis X, the arm portion 353 crosses the outer diameter side of the plate member 8 towards the motor 2.

[0133] As shown in FIG. 16, the tip side of arm portion 353 is bent downward (towards the rotation axis), and then a connecting portion 355 is connected to a support portion 354 fixed to the upper surface.

[0134] 18, a base end 361 in the longitudinal direction of the detent spring 36 is fixed to the fourth box 14 by a bolt B. The tip side of the detent spring 36, where a roller 365 is provided, is elastically displaceable in the radial direction of the base 351 of the manual plate 35. The tip side of the detent spring 36 is in pressure contact with the outer periphery (recess) of the base 351 of the manual plate 35.

[0135] In this embodiment, the manual shaft 37 rotates about the rotation axis Y in conjunction with switching between a driving mode and a parking mode of the vehicle on which the power transmission device 1 is mounted. When the manual shaft 37 rotates, the manual plate 35 fixed to the manual shaft 37 also rotates around the rotation axis Y. As a result, an arm 353 extending from a base 351 of the manual plate 35 and a connecting part 355 fixed to a support part 354 at the tip of the arm 353 are displaced in the circumferential direction around the rotation axis Y. The park rod 32 connected to the connecting part 355 is also displaced in the longitudinal direction of the park rod 32.

[0136] As shown in Fig. 2, a strainer chamber SR (second chamber) is provided adjacent to the gear chamber Sb below the gear chamber Sb of the fourth box 14. A strainer 90 is disposed inside the strainer chamber SR. Although not shown in Fig. 2 because it is only a schematic illustration, the strainer 90 is fixed inside the strainer chamber SR by a fixing device (not shown). FIG. 19 is an enlarged view of the strainer chamber SR and its surroundings. 19, the strainer chamber SR is a space surrounded by the support wall portion 146, the jacket portion 143, and the cover portion 144, and is provided apart from the gear chamber Sb. In other words, the strainer chamber SR is separated from the gear chamber Sb by the support wall portion 146 which is the inner wall of the fourth box 14.

[0137] A step portion 146c formed of a plurality of steps is provided at the lower portion of the support wall portion 146. The step portion 146c gradually increases in diameter from a joint portion 146b with the lid portion 144 toward a joint portion 142 with the second box 12. The jacket portion 143 is a wall portion that covers the outer periphery (radial outward) of the step portion 146c. The jacket portion 143 extends along the direction of the rotation axis X. A base end portion 143a provided on one end side of the step portion 146c in the direction of the rotation axis X is connected to a joint portion 142 at the bottom of the fourth box 14. A lid portion 144 is joined to a joint portion 143b provided on the other end side of the step portion 146c in the direction of the rotation axis X.

[0138] An inner wall surface 143c of the jacket portion 143 faces the step portion 146c with a gap therebetween, and the gap gradually narrows from the joint portion 143b toward the base end portion 143a. The joint portion 143b of the jacket portion 143 and the joint portion 146b of the support wall portion 146 form an opening portion SRo of the strainer chamber SR. The lid portion 144 closes the opening portion SRo of the strainer chamber SR.

[0139] In this way, the strainer chamber SR provided by utilizing the step portion 146c of the support wall portion 146 overlaps with the gear chamber Sb in the direction of the rotation axis X and in the radial direction of the rotation axis X. In the fourth box 14, the outer diameter of the step portion 146c of the support wall portion 146 becomes smaller as it moves away from the second box 12. Therefore, there is a space on the outer diameter side of the step portion 146c. The size of this space in the radial direction increases toward the left side in FIG. 19. In this embodiment, the strainer chamber SR is provided by utilizing this space. The stepped portion 146c has a reduced diameter relative to the peripheral wall portion 121 of the second box 12. As shown in Fig. 2, a part of the jacket portion 143 of the strainer chamber SR overlaps in the direction of the rotation axis X with the peripheral wall portion 121 of the second box 12 that constitutes the motor chamber Sa.

[0140] An opening 146d that communicates between the gear chamber Sb and the strainer chamber SR is formed in the step portion 146c. The opening 146d is located on the side of the surface 80b of the plate member 8 in the direction of the rotation axis X. The opening 146d penetrates the support wall portion 146 in the radial direction of the rotation axis X and opens vertically upward. A portion of the oil OL in the oil reservoir OP of the gear chamber Sb also flows into the strainer chamber SR through this opening 146d, forming an oil pool inside the strainer chamber SR.

[0141] The strainer 90 disposed inside the strainer chamber SR includes a main body 91 and a suction port 92 (pump inlet). The main body 91 is, for example, a hollow container. A filter F for filtering the oil OL is disposed inside the main body 91. The suction port 92 can be, for example, a cylindrical member protruding downward from the bottom surface of the main body 91. At least the suction port 92 of the strainer 90 is immersed in the oil pool in the strainer chamber SR, i.e., it is submerged in the oil. The oil OL is introduced into the main body 91 through the suction port 92.

[0142] The strainer 90 is connected to a suction port 95a of an oil pump 95 (pump) provided outside the strainer chamber SR via a pipe PI. The oil pump 95 may be, for example, an electric oil pump driven by a motor (not shown). The oil pump 95 is controlled by a control device (not shown).

[0143] The discharge port 95b of the oil pump 95 is connected to oil holes Ha, Hb, and Hc (see FIG. 2) formed in the upper part of the main box 10 via piping (not shown) arranged inside the vehicle. The oil hole Ha is formed in the upper part of the fourth box 14, on the outer diameter side of the differential case 50. The oil hole Hb is formed in the upper part of the second box 12, on the outer diameter side of the coil end 251b of the motor 2. The oil hole Hc is formed in the upper part of the third box 13, near the coil end 253a of the motor 2.

[0144] The operation of the power transmission device 1 having such a configuration will now be described. As shown in FIG. 1, 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 a motor 2.

[0145] When the motor 2 is driven and the rotor core 21 rotates around the rotation axis X, the rotation is input to the sun gear 41 of the planetary reduction gear 4 via the motor shaft 20 which rotates integrally with the rotor core 21 .

[0146] 3, in the planetary reduction gear 4, the sun gear 41 serves as an input portion of the output rotation of the motor 2. A differential case 50 supporting the stepped pinion gear 43 serves as an output portion of the input rotation.

[0147] When the sun gear 41 rotates around the rotation axis X by the input rotation, the stepped pinion gear 43 (large diameter gear portion 431, small diameter gear portion 432) rotates around the axis X1 by the rotation input from the sun gear 41 side. Here, the small diameter gear portion 432 of the stepped pinion gear 43 meshes with the ring gear 42 fixed to the inner periphery of the fourth box 14. Therefore, the stepped pinion gear 43 revolves around the rotation axis X while rotating about the axis line X1.

[0148] Here, in the stepped pinion gear 43, the outer diameter R2 of the small diameter gear portion 432 is smaller than the outer diameter R1 of the large diameter gear portion 431 (see FIG. 3). As a result, the differential case 50 (first case portion 6, 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. Therefore, the rotation input to the sun gear 41 of the planetary reduction gear 4 is greatly reduced in speed by the stepped pinion gear 43. The reduced rotation is output to the differential case 50 (differential mechanism 5).

[0149] Then, as the differential case 50 rotates about the rotation axis X by the input rotation, the drive shafts DA, DB meshing with the pinion mate gears 52 rotate about the rotation axis X inside the differential case 50. As a result, the left and right drive wheels (not shown) of the vehicle on which the power transmission device 1 is mounted rotate by the transmitted rotational driving force.

[0150] 2, an oil reservoir OP is formed inside the motor chamber Sa and the gear chamber Sb to store lubricating oil OL. The oil OL stored in the oil reservoir OP is scooped up by the rotation of the motor 2 and cools the motor 2. A portion of the scooped up oil OL also flows into the internal space Sc through the opening 136a of the connecting wall 136 and lubricates the bearings B1 and B4.

[0151] In the gear chamber Sb, the oil OL stored 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. The oil OL thus scooped up lubricates the meshing portion between the sun gear 41 and the large diameter gear portion 431, the meshing portion between the small diameter gear portion 432 and the ring gear 42, and the meshing portions between the pinion mate gear 52 and the side gears 54A and 54B.

[0152] As shown in FIG. 8, the differential case 50 rotates in the counterclockwise direction CCW about the rotation axis X when viewed from the third box 13 side. An oil catch portion 15 is provided on the upper portion of the fourth box 14. The oil catch portion 15 is located downstream in the rotation direction of the differential case 50, and most of the oil OL scooped up by the differential case 50 flows into the oil catch portion 15 and is supplied to an oil guide 152 placed on a support base portion 151 within the oil catch portion 15. As shown in FIG. 10, some of the oil OL supplied to the oil guide 152 drops from a tip 154b and lubricates the park gear 30 of the park lock mechanism 3 located below (see FIG. 3).

[0153] In this way, most of the oil OL scooped up by the differential case 50 flows into the oil catch portion 15, but the oil OL that falls due to gravity returns to and is stored in the oil reservoir OP. A portion of the oil OL stored in the oil reservoir OP flows into the oil reservoir 128 due to gravity. The temperature of the oil OL rises due to the scooping up of the motor 2 and the differential case 50, but by flowing into the oil reservoir 128, the oil is cooled by the coolant CL flowing through the cooling path CP.

[0154] 19, a portion of the oil OL stored in the oil reservoir OP flows into the strainer chamber SR through the opening 146d due to gravity and centrifugal force generated by the upward movement of the differential case 50. In addition, a portion of the oil OL also flows into the strainer chamber SR due to negative pressure generated by the suction of the oil pump 95.

[0155] When the oil pump 95 is driven, the oil OL in the strainer chamber SR is sucked through the suction port 92 of the strainer 90. The oil OL introduced into the main body 91 of the strainer 90 passes through the filter F, whereby impurities are filtered out. The filtered oil OL is sucked into the suction port 95a of the oil pump 95 through the pipe PI.

[0156] The oil OL sucked into the oil pump 95 is discharged from the discharge port 95b. The oil OL discharged from the discharge port 95b is supplied to the oil holes Ha, Hb, and Hc (see FIG. 2) inside the main box 10. The oil OL supplied to the oil hole Ha is supplied to the planetary reduction gear 4 and the differential case 50 in the fourth box 14. The oil OL supplied to the oil hole Hb is supplied to the coil end 253b side of the motor 2 and the park lock mechanism 3. The oil OL supplied to the oil hole Hc is supplied to the coil end 253a side of the motor 2. In this way, the power transmission device 1 is provided with a mechanism for filtering and circulating the oil OL used for lubricating and cooling each component.

[0157] In the embodiment, the strainer 90 is disposed in the strainer chamber SR. The strainer chamber SR is provided away from the gear chamber Sb that houses the planetary reduction gear 4 and the differential case 50, which are the gear mechanism. Specifically, the strainer chamber SR is separated from the gear chamber Sb by the support wall portion 146. Here, it is also conceivable to dispose the strainer 90 so as to be submerged in the oil reservoir OP of the gear chamber Sb. In this case, the amount of oil OL near the suction port 92 of the strainer 90 may decrease as the differential case 50 scoops up the oil OL in the oil reservoir OP. If the oil pump 95 is operated in this state, air suction of the oil pump 95 may occur, which may affect the suction performance of the oil pump 95.

[0158] On the other hand, in the embodiment, the strainer 90 is disposed in a strainer chamber SR separated from the gear chamber Sb. This reduces a decrease in the amount of oil OL near the suction port 92 of the strainer 90 caused by the oil OL being scooped up in the differential case 50. This reduces air suction by the oil pump 95.

[0159] Furthermore, when the main body 91 of the strainer 90 is disposed in the gear chamber Sb, the layout of other components is likely to be restricted because the strainer 90 requires space. By disposing the strainer 90 in the strainer chamber SR, the volume of the main body 91 can be secured while improving the degree of freedom in the layout of components in the gear chamber Sb.

[0160] In the embodiment, the strainer chamber SR is provided by utilizing the step portion 146c of the support wall portion 146 of the fourth box 14. The strainer chamber SR overlaps with the gear chamber Sb in the direction of the rotation axis X and in the radial direction of the rotation axis X. This reduces the strainer chamber SR from protruding from the gear chamber Sb in the direction of the rotation axis X and in the radial direction, improving the layout of the power transmission device 1. In addition, since the strainer chamber SR is located below the gear chamber Sb, the oil OL easily flows from the oil reservoir OP into the strainer chamber SR due to gravity. In addition, a part of the jacket portion 143 of the strainer chamber SR overlaps with the peripheral wall portion 121 of the second box 12 constituting the motor chamber Sa in the direction of the rotation axis X. This reduces the strainer chamber SR from protruding from the motor chamber Sa in the radial direction of the rotation axis X.

[0161] As described above, the power transmission device 1 according to the embodiment has the following configuration. (1) A power transmission device 1 includes: Motor 2; a planetary reduction gear 4 and a differential mechanism 5 (gear mechanism) connected downstream of the motor 2; an oil pump 95 (pump) into which oil OL is sucked through a suction port 92 (pump inlet) of a strainer 90; The pump has a main body box 10 (box) having a gear chamber Sb (first chamber) that houses the planetary reduction gear 4 and the differential mechanism 5 (gear mechanism), and a strainer chamber SR (second chamber) in which the suction port 92 (pump inlet) of the strainer 90 is located.

[0162] When the suction port 92 (pump inlet) of the strainer 90 is disposed inside the gear chamber Sb, the oil OL on the outer periphery of the differential case 50 is scooped up as the differential case 50 constituting the differential mechanism 5 (differential gear) rotates. This scooping up reduces the amount of oil near the suction port 92 of the strainer 90, which may cause the oil pump 95 to suck in air. The strainer chamber SR (second chamber), which is provided separated (isolated) from the gear chamber Sb (first chamber), is less susceptible to the reduction in the amount of oil caused by the rotation of the differential case 50. Therefore, by arranging the suction port 92 of the strainer 90, which is the pump inlet, in the strainer chamber SR, it is possible to reduce air suction by the oil pump 95.

[0163] The first chamber is a "space surrounded by a first wall," and the second chamber is a "space surrounded by a second wall." However, the first wall and the second wall may share a part. In the embodiment, the gear chamber Sb (first chamber) is a space surrounded by the support wall portion 146 of the fourth box 14, and the strainer chamber SR (second chamber) is a space surrounded by the support wall portion 146 and the jacket portion 143. The gear chamber Sb and the strainer chamber SR share the support wall portion 146. In other words, this structure is a structure in which a partition wall is provided between the suction port 92 (pump inlet) of the strainer 90 and the planetary reduction gear 4 and the differential mechanism 5 (gear mechanism).

[0164] The "pump inlet" is in contact with the oil reservoir, i.e., immersed in the oil reservoir, and is connected to the suction port 95a of the oil pump 95. When the strainer 90 is connected to the suction port 95a of the oil pump 95 as in the embodiment, the suction port 92 of the strainer 90 corresponds to the "pump inlet". Also, for example, when the suction port 95a of the oil pump 95 is in direct contact with (immersed in) the oil reservoir, the suction port 95a of the oil pump 95 corresponds to the "pump inlet". This case will be described in Modification 1 below.

[0165] The "gear mechanism" refers to the entire mechanism including gears. For example, in this embodiment, the gear mechanism is made up of a planetary reduction gear 4 and a differential mechanism 5 (differential gear).

[0166] "Connected downstream" means a connection relationship in which power is transmitted from a component arranged upstream to a component arranged downstream. For example, "planetary reduction gear 4 connected downstream of motor 2" means that power is transmitted from motor 2 to planetary reduction gear 4.

[0167] For example, a gear mechanism may be connected downstream of the motor 2 via a speed change mechanism, a clutch, etc. In this case, the connection is such that the power of the motor 2 is transmitted to the gear mechanism via the speed change mechanism, a clutch, etc. The speed change mechanism is a mechanism having a speed change function, and includes, for example, a stepped speed change mechanism and a continuously variable speed change mechanism.

[0168] A "power transmission device" refers to a power train device (transmission, reduction gear, etc.) equipped with a rotating electric machine.

[0169] (2) The power transmission device 1 has a drive shaft DA (drive shaft) that is connected downstream of the planetary reduction gear 4 and the differential mechanism 5 (gear mechanism) and that is disposed penetrating the inner periphery of the motor 2 .

[0170] In a power transmission device 1 having such a configuration, by arranging the suction port 92 (pump inlet) of the strainer 90 in the strainer chamber SR (second chamber), it is no longer necessary to consider the layout for arranging the suction port 92 in the gear chamber Sb (first chamber) which houses the planetary reduction gear 4 and the differential mechanism 5 (gear mechanism), thereby improving the freedom of layout design of the gear chamber Sb.

[0171] (3) The main body box 10 (box) has an opening 146d that communicates between the gear chamber Sb (first chamber) and the strainer chamber SR (second chamber). By providing the opening 146d, it is possible to introduce the oil OL from the gear chamber Sb into the strainer chamber SR by utilizing gravity or the centrifugal force caused by the upward movement of the differential case 50. This promotes an increase in the amount of oil in the strainer chamber SR, and further reduces the air suction of the oil pump 95.

[0172] (4) The pump inlet is configured as a suction port 92 of the strainer 90. At least a portion of a main body 91 of the strainer 90 is disposed in a strainer chamber SR (second chamber).

[0173] The main body 91 of the strainer 90 requires space for placement. By placing the main body 91 in the strainer chamber SR isolated from the gear chamber Sb, the degree of freedom in the layout of the gear chamber Sb can be improved. In the embodiment, the entire main body 91 is placed in the strainer chamber SR, but it is also possible to place a part of the main body 91 in the strainer chamber SR and the remainder outside the strainer chamber SR. This makes it possible to increase the volume of the main body 91. In this case, the main body parts 91 placed inside and outside the strainer chamber SR may be connected by piping or the like.

[0174] (5) The strainer chamber SR (second chamber) overlaps with the gear chamber Sb (first chamber) in the direction of the rotation axis X (axial direction).

[0175] In the embodiment, the strainer chamber SR is provided by utilizing the step portion 146c of the fourth box 14, and overlaps with the gear chamber Sb in the direction of the rotation axis X. This reduces the strainer chamber SR from protruding radially outward from the gear chamber Sb, and improves the layout flexibility of the power transmission device 1.

[0176] (6) The strainer chamber SR (second chamber) overlaps with the gear chamber Sb (first chamber) in the radial direction of the rotating shaft X (radial direction).

[0177] This can reduce the strainer chamber SR from protruding in the direction of the rotation axis X from the gear chamber Sb, improving layout flexibility. In the embodiment, the strainer chamber SR overlaps with the gear chamber Sb both in the direction of the rotating shaft X and in the radial direction of the rotating shaft X. In this case, it is possible to reduce the protrusion of the strainer chamber SR in both the radial direction of the rotating shaft X and the direction of the rotating shaft X, and it is possible to realize a well-balanced layout.

[0178] (7) The strainer chamber SR (second chamber) is located below the gear chamber Sb (first chamber). By arranging the gear chamber Sb in a position where the oil OL is likely to accumulate due to gravity, it is possible to promote an increase in the amount of oil in the strainer chamber SR. Note that "below the gear chamber Sb" means the lower side in the vertical direction when the power transmission device 1 is mounted on a vehicle.

[0179] (8) The gear mechanism includes a planetary reduction gear 4. As described above, the gear mechanism refers to the entire mechanism including gears, and in this embodiment, the planetary reduction gear 4 is included as the gear mechanism.

[0180] (Variation 1) 20 to 22 are diagrams showing an example of the configuration of an oil pump 95 according to the first modification. In the embodiment, an example has been described in which the mechanism for filtering and circulating the oil OL in the power transmission device 1 is configured with the oil pump 95 and the strainer 90 (see FIG. 2). However, the circulation mechanism for the oil OL is not limited to the example in the embodiment, and for example, the strainer 90 may be omitted.

[0181] As shown in FIG. 20, when the strainer is omitted, a filter F for filtering out foreign matter may be disposed inside the pipe PI connected to the suction port 95a of the oil pump 95. 20, when the oil pump 95 is driven, the oil OL is sucked from the end PE of the pipe PI, passes through the filter F, and is sucked into the suction port 95a of the oil pump 95. That is, the end PE of the pipe PI corresponds to the "pump inlet."

[0182] Fig. 21 is an example in which the end PE of the pipe PI corresponds to the "pump inlet" as in Fig. 20, but in Fig. 21, the end PE of the pipe PI is enlarged in diameter and a filter F is disposed at the end PE. By configuring as in Fig. 21, the size of the filter F can be increased. 20 and 21, both the oil pump 95 and the pipe PI may be disposed in the strainer chamber SR (see FIG. 2). Alternatively, the oil pump 95 may be disposed outside the strainer chamber SR, and a portion of the pipe PI may be disposed in the strainer chamber SR. In this case, it is preferable that at least the end PE of the pipe PI is disposed in the strainer chamber SR so as to be immersed in the oil OL.

[0183] Fig. 22 shows an example in which piping is also omitted, and the filter F is placed directly at the suction port 95a of the oil pump 95. In this case, the suction port 95a corresponds to the "pump inlet." In the configuration of Fig. 22, the oil pump 95 is preferably placed in the strainer chamber SR, with the suction port 95a immersed in the oil OL stored in the strainer chamber SR.

[0184] (Variation 2) FIG. 23 is a diagram showing the configuration of a strainer chamber SR according to the second modification. In the second modification, an example will be described in which the strainer 90 is omitted and the strainer chamber SR itself serves as the strainer. As shown in Fig. 23, in the second modification, the strainer chamber SR is provided by utilizing the step portion 146c of the fourth box 14, but the cover portion 144 is attached closer to the joint portion 142 than in the embodiment. This makes the strainer chamber SR smaller than in the embodiment. Also, in the embodiment, the opening 146d connecting the gear chamber Sb and the strainer chamber SR is provided on the surface 80b side of the plate member 8 (see Fig. 19), but in the second modification, the opening 146d is provided on the surface 80a side of the plate member 8.

[0185] A filter F that filters the oil OL is disposed inside the strainer chamber SR. The strainer chamber SR and a suction port 95a of the oil pump 95 are connected via a pipe PI. In the second modification, an opening 146d provided in the support wall portion 146 is a suction port of the strainer and functions as a “pump inlet.” The inside of the strainer chamber SR in which the filter F is disposed functions as a main body of the strainer that filters the oil OL.

[0186] As in the embodiment, gravity and centrifugal force caused by the upward movement of the differential case 50 cause oil OL to flow from the oil reservoir OP of the gear chamber Sb into the strainer chamber SR through the opening 146d. Furthermore, when the oil pump 95 is driven, the oil OL in the gear chamber Sb is sucked into the strainer chamber SR through the opening 146d, which is a suction port. The oil OL is filtered by passing through a filter F arranged in the strainer chamber SR. The filtered oil OL is sucked into the oil pump 95 through the pipe PI.

[0187] In the second modification, the opening 146d corresponding to the "pump inlet" is open vertically upward, so that the oil OL can be easily sucked in by gravity. Also, the opening 146d is moved from the surface 80b side facing the gear mechanism (planetary reduction gear 4, differential case 50) of the plate member 8 to the surface 80a side facing the motor 2.

[0188] As described above, the amount of oil may decrease near the differential case 50 due to the oil OL being scooped up in the differential case 50. In the second modification, the opening 146d corresponding to the "pump inlet" is positioned away from the differential case 50, thereby reducing air intake by the oil pump 95.

[0189] The second gear chamber Sb2, in which the opening 146d is open, and the motor chamber Sa are in communication with each other via the opening 120b of the beam portion 120. The oil OL warmed by the stator core 25 of the motor 2, which is a heat source, is discharged from the opening 120b (discharge port) and stored in the oil storage portion OP of the second gear chamber Sb2. Therefore, the opening 146d provided in the second gear chamber Sb2 at a position close to the stator core 25 can easily suck in the oil OL warmed by the stator core 25. At low temperatures, the viscosity of the oil OL is likely to be high, but by arranging the opening 146d close to the motor 2, the suction performance of the oil pump 95 can be improved even at low temperatures when the viscosity of the oil OL is likely to be high.

[0190] Furthermore, in Modification 2, by integrating the strainer into the strainer chamber SR, it is possible to reduce the size of the strainer chamber SR and improve the layout flexibility of the power transmission device 1. The strainer chamber SR may have the same volume as in the embodiment, which allows the volume of the strainer to be increased.

[0191] As described above, the power transmission device 1 according to the second modification has the following configuration. (9) The pump inlet is provided as an opening 146d in the support wall portion 146 which is the inner wall of the strainer chamber SR (second chamber). The pump inlet for sucking the oil OL itself occupies a small area, so by providing it on the support wall portion 146 which is the inner wall of the strainer chamber SR, the degree of freedom in layout of the pump inlet can be improved.

[0192] In addition, by arranging the pump inlet on the inner wall of the strainer chamber SR, the layout options increase, as described below, and the layout freedom can be improved. (A) The components connected downstream of the pump inlet (oil pump and / or strainer) can be disposed outside the strainer chamber SR. For example, as in the second modification, the oil pump 95 can be disposed outside the strainer chamber SR. Also, for example, the filter F may not be disposed inside the strainer chamber SR, and the entire strainer chamber SR may function as the suction port of the strainer. In this case, the main body of the strainer in which the filter F is disposed may be provided separately outside the strainer chamber SR. (B) The components connected downstream of the pump inlet (the pump and / or the strainer) can be disposed in the strainer chamber SR at a location separate from the pump inlet. For example, the configurations of FIGS. 20 and 21 may be applied, with the oil pump 95 disposed in the strainer chamber SR, and the suction port 95a of the oil pump 95 directly connected to the opening 146d by the pipe PI.

[0193] (Variation 3) In the embodiment, an example in which the strainer chamber SR is provided below the gear chamber Sb has been described, but the present invention is not limited to this, and the position of the strainer chamber SR can be changed as appropriate. 24 to 27 are schematic diagrams showing the layout of the strainer chamber SR according to the third modification. 24 to 27, the positional relationship between the main body box 10 and the strainer chamber SR is shown typically, and detailed internal configurations are omitted, but the configurations of the above-described embodiment and modified examples can be applied.

[0194] As shown in FIG. 24, the strainer chamber SR can be disposed below the motor chamber Sa. As shown in FIG. 25, the strainer chamber SR can be disposed to the side of the motor chamber Sa. In the configurations of Figs. 24 and 25, the strainer chamber SR (second chamber) is disposed at a position where it overlaps with the motor 2 in the radial direction. Although not shown, the strainer chamber SR and the motor chamber Sa are connected by an oil passage. As shown by the arrow in the figure, the oil OL in the motor chamber Sa flows into the strainer chamber SR. The oil passage may be provided, for example, in the inner wall of the main body box 10 as in the embodiment, and may be an opening that communicates between the strainer chamber SR and the motor chamber Sa. Also, as in the example of Fig. 26, the oil passage may be provided in both the upper and lower parts of the motor chamber Sa to facilitate the inflow of the oil OL.

[0195] The oil OL in the motor chamber Sa is heated by the stator core 25 of the motor 2, which serves as a heat source. The oil OL heated in the motor chamber Sa flows into the strainer chamber SR. This improves the oil suction performance of the strainer suction port (pump inlet) even at low temperatures when the viscosity of the oil OL is high.

[0196] As shown in FIG. 26, a strainer chamber SR can be provided above the main body box 10. The area in which the strainer chamber SR is provided is not limited, and for example, the strainer chamber SR may be provided so as to extend across the motor chamber Sa and the gear chamber Sb in the direction of the rotation axis X. Alternatively, the strainer chamber SR may be provided above either the motor chamber Sa or the gear chamber Sb.

[0197] In this case, the strainer chamber SR may be configured to introduce the oil OL scooped up by the rotation of the differential case 50 or the motor 2. For example, an oil passage or the like may be provided so that the oil OL that has flowed into the oil catch portion 15 (see FIG. 9) by being scooped up by the differential case 50 is introduced into the strainer chamber SR.

[0198] 25 and 26, by arranging the strainer chamber SR to the side or above the motor chamber Sa, the strainer chamber SR (second chamber) overlaps with the motor chamber Sa in the radial direction of the rotating shaft X. This makes it possible to reduce the strainer chamber SR protruding from the motor chamber Sa in the direction of the rotating shaft X, improving layout flexibility.

[0199] The strainer chamber SR may be disposed to the side or above the gear chamber Sb. In this case, similar to the embodiment, the strainer chamber SR (second chamber) overlaps with the gear chamber Sb (first chamber) in the radial direction of the rotating shaft X. This reduces the strainer chamber SR protruding from the gear chamber Sb in the direction of the rotating shaft X, improving the layout flexibility.

[0200] As shown in Fig. 27, a strainer chamber SR can be provided on the outer periphery of each of the drive shafts DA, DB (radially outward from the rotation axis X). Fig. 27 shows an example in which a strainer chamber SR is provided on the outer periphery of both the drive shafts DA, DB. Although not shown in the figure, the strainer chamber SR on the drive shaft DA side is connected to the motor chamber Sa by an oil passage, and the oil OL in the motor chamber Sa flows into it. The strainer chamber SR on the drive shaft DB side is connected to the gear chamber Sb by an oil passage, and the oil OL in the gear chamber Sb flows into it.

[0201] By providing strainer chambers SR in two locations, the volume of the strainer can be increased, but it is also possible to provide one in only one location. Also, by providing the strainer chambers SR around the drive shafts DA and DB, the strainer chamber SR (second chamber) overlaps with the gear chamber Sb (first chamber) in the direction of the rotation axis X (axial direction). This makes it possible to reduce the strainer chamber SR protruding radially outward from the gear chamber Sb, improving layout flexibility.

[0202] As described above, one example of the power transmission device 1 of the third modification has the following configuration. (10) The strainer chamber SR (second chamber) overlaps with the motor 2 in the radial direction. 27, by locating the strainer chamber SR (second chamber) in a position close to the motor 2, which is the heat source, even at low temperatures when the viscosity of the oil OL is high, the oil OL in the strainer chamber SR can be warmed by the heat of the motor 2. This makes it possible to improve the oil suction performance of the pump inlet (e.g., the suction port of the strainer) located in the strainer chamber SR, even at low temperatures.

[0203] (Other variations) In the embodiment, an example has been described in which an electric oil pump is used as the oil pump 95, but a mechanical oil pump may also be used. The mechanical oil pump may be disposed, for example, in the motor chamber Sa of the main body box 10 and driven by using the rotation of the motor 2.

[0204] Although an embodiment of the present invention has been described above, the above embodiment merely illustrates one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment. [Explanation of symbols]

[0205] 1: Power transmission device 10: Main unit box 2: Motor 4: Planetary reduction gear (gear mechanism) 5: Differential mechanism (gear mechanism) 90: Strainer 91: Main body 92: Suction port (pump inlet) 95: Oil pump (pump) DA: Drive shaft SR: Strainer chamber (chamber 2) Sb: Gear chamber (first chamber)

Claims

1. A motor; a gear mechanism connected downstream of the motor; A strainer having a body and a pump inlet connected to the body; a pump into which oil is drawn via the pump inlet; a box including a first chamber that houses the gear mechanism and has an oil reservoir, and a second chamber in which the pump inlet and the main body are disposed, When viewed in a radial direction, the second chamber is offset from the motor, When viewed from a radial direction, the main body portion overlaps with the first chamber across a support wall portion that surrounds an outer periphery of the gear mechanism, The support wall portion has an opening portion that communicates with the first chamber and the second chamber and faces the oil reservoir portion, A power transmission device, wherein the support wall portion has a portion whose outer diameter decreases with increasing distance from the motor, and the main body portion has a portion that overlaps the portion of the support wall portion where the outer diameter decreases when viewed in the radial direction.

2. A motor; a gear mechanism connected downstream of the motor; A strainer having a body and a pump inlet connected to the body; a pump into which oil is drawn via the pump inlet; a box having a first chamber that houses the gear mechanism, a second chamber in which the pump inlet and the main body are disposed, and a third chamber that houses the motor, The second chamber is offset from the third chamber when viewed in a radial direction, the other of the first chamber and the third chamber is disposed between the second chamber and one of the first chamber and the third chamber in the axial direction, When viewed from a radial direction, the second chamber overlaps a portion of a drive shaft connected downstream of the gear mechanism that is located outside the box, A power transmission device, wherein the main body portion has a portion that overlaps with the first chamber when viewed in the axial direction.

3. In claim 1 or 2, a power transmission device having a drive shaft connected downstream of the gear mechanism and disposed through an inner circumference of the motor;

4. In claim 2, The box has an opening that communicates between the first chamber and the second chamber.

5. In claim 2, The pump inlet is configured as a suction port of a strainer; At least a portion of the main body of the strainer is disposed in the second chamber.

6. In any one of claims 1 to 4, The pump inlet is provided in an inner wall of the second chamber.

7. In any one of claims 1 to 6, The second chamber is located below the first chamber.

8. In any one of claims 1 to 6, The gear mechanism includes a planetary reduction gear.

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