CN113472137B

CN113472137B - Driving device

Info

Publication number: CN113472137B
Application number: CN202110320449.6A
Authority: CN
Inventors: 水谷竜彦; 石川勇树; 舘形和典; 青野嘉之
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2020-03-31
Filing date: 2021-03-25
Publication date: 2024-04-05
Anticipated expiration: 2041-03-25
Also published as: JP2021162079A; JP7463809B2; CN113472137A

Abstract

One embodiment of the driving device of the present invention includes: a motor having a rotor and a stator, the rotor having a motor rotation shaft and a rotor body fixed to the motor rotation shaft, the stator surrounding the rotor; a gear part connected with the motor rotating shaft; a plurality of bearings that rotatably support the motor shaft; and a housing accommodating the motor and the gear portion. The housing has a partition wall portion that partitions an interior of the motor housing portion from an interior of the gear housing portion. The partition wall portion has: a storage section; a first holding portion that holds the first bearing inside; a second holding portion that holds a second bearing inside; and a communication hole that communicates at least one of the motor housing portion and the gear housing portion with the reservoir portion. The interior of the first holding portion is connected to the interior of the second holding portion via the interior of the reservoir.

Description

Driving device

Technical Field

The present invention relates to a driving device.

Background

In patent document 1, the spline joint includes a spline fitting portion formed by spline fitting an outer peripheral tooth formed on the first rotary member and an inner peripheral tooth formed on the second rotary member. In a spline joint configured to supply lubricating oil from an oil passage formed inside a first rotary member to the outside of the spline fitting portion via the spline fitting portion, a notch is formed at a part in the circumferential direction at the tip end of an outer peripheral tooth of the first rotary member, and the notch penetrates from the axial center of the first rotary member to the outer peripheral surface. The opening area of the notch is set to be equal to or larger than the maximum value of the fitting gap in the spline fitting portion.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2017-075627

In the spline-coupled coupling portion, lubrication by lubricating oil is required to prevent wear and the like of the inner peripheral teeth and the outer peripheral teeth, and further, it is required to suppress wear and the like by improving the lubricity of the coupling portion.

Disclosure of Invention

An object of the present invention is to provide a driving device that improves the lubrication performance of a spline-coupled joint.

One embodiment of the driving device of the present invention includes: a motor having a rotor with a motor rotation shaft rotating about a rotation axis and a rotor body fixed to the motor rotation shaft, and a stator surrounding the rotor; the gear part is connected with the motor rotating shaft; a plurality of bearings that rotatably support the motor shaft; and a housing that houses the motor and the gear portion. The motor shaft has: a first rotating shaft fixed to the rotor body; one side of the second rotating shaft is connected with the first rotating shaft, and the other side of the second rotating shaft is connected with the gear part; a spline shaft portion provided in one of the first rotating shaft and the second rotating shaft, the spline shaft portion having a plurality of external teeth portions on an outer peripheral surface; a spline hole portion provided in the other of the first rotating shaft and the second rotating shaft, the spline hole portion being fitted with the spline shaft portion; and a plurality of internal teeth portions provided on the inner peripheral surface of the spline hole portion, the plurality of internal teeth portions being meshed with the plurality of external teeth portions. The housing has: a motor housing unit configured to house the motor therein; a gear housing portion that houses the gear portion therein; a partition wall portion that partitions an interior of the motor housing portion from an interior of the gear housing portion; and a reservoir portion that stores oil around the one rotating shaft. The bearing includes: a first bearing that rotatably supports the first rotation shaft; and a second bearing that supports the second rotating shaft to be rotatable. The partition wall portion has: the storage portion; a first holding portion that holds the first bearing inside; a second holding portion that holds the second bearing inside; and a communication hole that communicates any one of the motor housing portion and the gear housing portion with the reservoir portion. The interior of the first holding portion is connected to the interior of the second holding portion via the interior of the reservoir.

According to one aspect of the present invention, in the drive device, the lubrication performance of the joint portion of the spline joint can be improved.

Drawings

Fig. 1 is a schematic configuration diagram schematically showing a driving device according to a first embodiment.

Fig. 2 is a cross-sectional view showing a part of a motor shaft according to the first embodiment.

Fig. 3 is a diagram schematically showing the structures of the partition wall portion and the communication hole of the first embodiment.

Fig. 4 is a perspective view showing a part of the first rotating shaft according to the first embodiment.

Fig. 5 is a perspective view showing a part of the second rotating shaft and a part of the gear portion according to the first embodiment.

Fig. 6 is a cross-sectional view showing meshing of the external tooth portion and the internal tooth portion of the first embodiment.

Fig. 7 is a perspective view showing a part of the second rotating shaft and a part of the gear portion in the modification of the first embodiment.

Fig. 8 is a cross-sectional view showing a part of a motor shaft according to the second embodiment.

(symbol description)

1. A driving device;

2. a motor;

3. a gear portion;

6. a housing;

20. a rotor;

21. a motor shaft;

21a first rotation axis;

21b, 121b second axis of rotation;

21c, 21d oil passage portions;

22. an expanded diameter portion;

23a through holes;

24. a rotor body;

26. 126 spline shaft portion;

26a external teeth portion;

26b, 126b feed holes;

26c, 126c supply paths;

26d, 126d hollow portions;

27. a bearing;

27a first bearing;

27b second bearings;

28. a spline hole portion;

28a inner teeth;

29. 70 gaps;

30. a stator;

41. a first helical gear portion (helical gear portion);

61. a motor housing part;

62. a gear housing part;

63. a partition wall portion;

66a first retaining portion;

66b second holding portion;

66c storage;

67. 267 communicating holes;

67a motor side opening;

267a gear side opening;

67b, 267b reservoir side openings;

93. a storage section;

93a, 93b oil supply holes;

99. 299 oil receiving portion;

j1 An axis of rotation;

o oil.

Detailed Description

In the following description, the vertical direction is described with reference to the positional relationship in the case where the rotation axis J1 of the driving device 1 of the present embodiment shown in the drawings is mounted on a vehicle on a horizontal road surface. Further, in the drawings, the XYZ coordinate system is appropriately represented as a three-dimensional rectangular coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the-Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction will be simply referred to as "upper side", and the lower side in the vertical direction will be simply referred to as "lower side". The X-axis direction is a direction orthogonal to the Z-axis direction, and is a direction along which the rotation axis J1 extends. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction.

The rotation axis J1 appropriately shown in each figure extends in the Y-axis direction, i.e., the left-right direction of the vehicle. In the following description, unless otherwise specified, a direction parallel to the rotation axis J1 is simply referred to as an "axial direction", a radial direction centered on the rotation axis J1 is simply referred to as a "radial direction", and a circumferential direction centered on the rotation axis J1, that is, an axial direction around the rotation axis J1 is simply referred to as a "circumferential direction". In the present specification, "parallel direction" also includes a substantially parallel direction, and "orthogonal direction" also includes a substantially orthogonal direction.

< first embodiment >, first embodiment

The driving device 1 of the present embodiment shown in fig. 1 is mounted on a vehicle such as a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHV), and an Electric Vehicle (EV) that uses a motor as a power source, and is used as the power source.

As shown in fig. 1, the driving device 1 has a motor 2, a gear portion 3, a housing 6, an oil pump 96, a cooler 97, a pipe 10, and a plurality of bearings 27, the gear portion 3 including a reduction gear 4 and a differential gear 5. In the present embodiment, the plurality of bearings 27 includes a first bearing 27a, a second bearing 27b, a third bearing 27c, and a fourth bearing 27d.

The housing 6 accommodates the motor 2 and the gear portion 3 therein. The housing 6 has a motor housing portion 61, a gear housing portion 62, and a partition wall portion 63. The motor 2 is accommodated in the motor accommodation portion 61. The gear portion 3 is accommodated in the gear accommodating portion 62. The gear housing 62 and the motor housing 61 are arranged along the rotation axis J1. The bottom 61f of the motor housing 61 is located above the bottom 62c of the gear housing 62. The partition wall 63 axially partitions the inside of the motor housing 61 and the inside of the gear housing 62. The partition wall 63 is provided with a connection hole 68 penetrating the partition wall 63 in the axial direction. The connection hole 68 connects the inside of the motor housing portion 61 with the inside of the gear housing portion 62. The partition wall 63 is located on the gear 3 side of the stator 30.

As shown in fig. 2, the partition wall 63 has a hole 66 penetrating the partition wall 63 in the axial direction. The hole 66 is provided for the motor shaft 21 to be described later to pass through. The hole 66 is, for example, a circular hole centered on the rotation axis J1. The hole portion 66 has a first holding portion 66a, a second holding portion 66b, and a reservoir portion 66c. That is, the partition wall portion 63 has a first holding portion 66a, a second holding portion 66b, and a reservoir portion 66c. Further, the housing 6 has a first holding portion 66a, a second holding portion 66b, and a reservoir portion 66c.

The first holding portion 66a is a portion that holds the first bearing 27a inside. The first holding portion 66a opens in the motor housing portion 61. The second holding portion 66b is a portion that holds the second bearing 27b inside. The second holding portion 66b opens into the gear housing portion 62. The second holding portion 66b has an inner diameter larger than that of the first holding portion 66a, for example. The second bearing 27b is a bearing having a larger diameter than the first bearing 27 a. The first bearing 27a is held by the first holding portion 66a. The second bearing 27b is held by the second holding portion 66b. The first bearing 27a may be a bearing having a larger diameter than the second bearing 27 b. At this time, the inner diameter of the first holding portion 66a is larger than the inner diameter of the second holding portion 66b.

The reservoir 66c is a portion where the oil supply O is stored around the second rotating shaft 21b described later. The reservoir 66c is located between the first and second holding portions 66a, 66b in the axial direction. The interior of the reservoir 66c is open toward both sides in the axial direction. The inside of the reservoir 66c is connected to the inside of the first holding portion 66a and the inside of the second holding portion 66 b. That is, the inside of the first holding portion 66a and the inside of the second holding portion 66b are connected via the inside of the reservoir portion 66c. Thereby, the oil O in the reservoir 66c can be supplied to the first bearing 27a held by the first holding portion 66a and the second bearing 27b held by the second holding portion 66 b. The inner diameter of the reservoir 66c is smaller than the inner diameter of the first holding portion 66 a.

The partition wall portion 63 is provided with a communication hole 67, the communication hole 67 extending in a direction away from the rotation axis J1. The communication hole 67 communicates one of the motor housing portion 61 and the gear housing portion 62 with the reservoir portion 66c. In the drive device 1, the oil O supplied to the region of either the motor housing portion 61 or the gear housing portion 62 is supplied to the reservoir portion 66c via the communication hole 67. For example, the oil O inside the reservoir 66c can be supplied to the first bearing 27a held by the first holding portion 66a and the second bearing 27b held by the second holding portion 66 b. Thereby, the lubrication performance of the first bearing 27a and the second bearing 27b can be improved. The oil O in the reservoir 66c is supplied to the spline shaft portion 26 described later, and thus the lubrication performance of the spline joint portion can be improved.

Fig. 3 is a diagram schematically showing the structures of the partition wall 63 and the communication hole 67 when viewed from the X-axis direction. In a state where the rotation axis J1 is arranged in the horizontal direction, the partition wall portion 63 has a reservoir-side opening 67b, and the reservoir-side opening 67b is located on the inner peripheral surface of the hole portion 66 penetrating in the Y-axis direction. The reservoir side opening 67b is located above the motor shaft 21. The oil O flowing into the communication hole 67 from the opening of either the motor housing portion 61 or the gear housing portion 62 is supplied from the reservoir-side opening 67b to the reservoir 66c. At this time, the oil O is supplied to the upper portion of the motor rotation shaft 21.

For example, the oil O is transmitted to the surface of the motor shaft 21 and supplied to the spline shaft portion 26 described later, and the lubrication performance of the spline joint portion can be improved. Further, by supplying the oil O to the upper portion of the motor rotation shaft 21, the oil O can be stably supplied to the spline joint regardless of the rotation direction of the motor rotation shaft 21. The reservoir-side opening 67b need not be located above the rotation axis J1, and may be located above the motor rotation shaft 21 within the diameter width of the motor rotation shaft 21.

In the first embodiment of the present invention, the communication hole 67 is formed obliquely to the rotation axis J1, penetrates the partition wall 63 in the radial direction, and communicates either one of the motor housing portion 61 and the gear housing portion 62 with the reservoir portion 66c.

For example, as shown in fig. 2, the partition wall 63 includes: a motor-side opening 67a, the motor-side opening 67a being an opening portion located on the outer peripheral surface of the partition wall 63; and a reservoir-side opening 67b, the reservoir-side opening 67b being located on an inner peripheral surface of the hole 66 penetrating the partition wall 63 in the axial direction. That is, the communication hole 67 has a motor-side opening 67a as an opening on one side, and a reservoir-side opening 67b on the other side of the communication hole 67. The oil O supplied to the motor housing portion 61 is supplied from the motor-side opening 67a to the reservoir portion 66c via the communication hole 67.

According to the present embodiment, the oil O flowing into the pipe 10 flows in the pipe 10 and is supplied to the stator 30 from the oil supply hole provided in the pipe 10. The supplied oil O is scattered by the stator 30 or the rotor 20, and a part of the scattered oil O adheres to the partition wall 63. The adhering oil O is transferred at the partition wall 63, and is immersed in the motor-side opening 67a of the communication hole 67, and is supplied to the reservoir 66c.

As shown in fig. 3, the motor-side opening 67a has an oil receiving portion 99 formed to have a larger diameter than the communication hole 67 and to receive the oil O transferred at the partition wall portion 63. Thus, by providing the oil receiving portion 99, the oil in the motor housing portion can be easily collected.

For example, the oil receiving portion 99 has an opening portion that communicates with the motor-side opening 67a and has a diameter larger than that of the motor-side opening 67 a. The opening of the oil receiving portion 99 opens in the motor housing portion 61. In addition, the opening of the oil receiving portion 99 preferably opens upward in the motor housing portion 61. At this time, the oil O supplied from the upper region of the motor housing portion 61 toward the upper portion of the motor 2 can be easily collected, and the oil O can be easily introduced into the communication hole 67. Further, more oil O can be taken in than when the opening toward the inside of the motor housing portion 61 is formed only with the diameter of the motor-side opening 67 a. In fig. 3, the oil receiving portion 99 is illustrated as a conical oil receiving portion, but the shape is not limited thereto. The shape of the oil receiving portion can be changed appropriately to be a box shape or the like.

The communication hole 67 extends straight between the motor-side opening 67a and the reservoir-side opening 67 b. The motor-side opening 67a is located in a region above the reservoir-side opening 67b and toward the motor housing 61 on the outer peripheral surface of the partition wall 63. In the present embodiment, the motor-side opening 67a is located above the first bearing 27a on the outer peripheral surface of the partition wall 63. The reservoir-side opening 67a is located below the motor-side opening 67 a. The motor-side opening 67a is located on the motor housing portion 61 side with respect to the reservoir-side opening 67 b. Accordingly, the communication hole 67 is inclined in a direction away from the motor housing portion 61 as going toward the lower side.

As shown in fig. 2, the first bearing 27a and the second bearing 27b are configured to be axially separated from each other. A reservoir 66c is provided between the first bearing 27a and the second bearing 27 b. The reservoir-side opening 67b opens at a reservoir 66c located between the first bearing 27a and the second bearing 27 b. The motor-side opening 67a is located on the first bearing 27a side. The reservoir-side opening 67b is located on the second bearing 27b side.

In the present embodiment, the second bearing 27b is a bearing having a larger diameter than the first bearing 27 a. At this time, an opening portion that opens on the outer peripheral surface of the partition wall portion 63 is located on the first bearing 27a side. Further, the reservoir-side opening 67b is located on the second bearing 27b side. Since the second bearing 27b on the large diameter side is a bearing with a high load, lubrication of the second bearing 27b on the large diameter side can be improved by forming the communication hole 67 toward the second bearing 27b on the large diameter side.

As shown in fig. 1, the casing 6 accommodates oil O as a refrigerant therein. In the present embodiment, the oil O is stored in the motor storage portion 61 and the gear storage portion 62. An oil reservoir P for storing the oil supply O is provided in a lower region inside the gear housing 62. The oil O in the oil reservoir P is fed into the motor housing 61 through an oil passage 90 described later. The oil O delivered to the inside of the motor housing portion 61 is stored in a lower region inside the motor housing portion 61. At least a part of the oil O stored in the motor housing 61 moves to the gear housing 62 through the connection hole 68 and returns to the oil reservoir P.

In the present specification, the term "oil is contained in a certain portion" is only required to be within a certain portion when the oil is at least in a part during driving of the motor, and the oil may not be within a certain portion when the motor is stopped. For example, in the present embodiment, the oil O may be contained in the motor containing portion 61 as long as the oil O is located in the motor containing portion 61 during at least a part of the driving of the motor 2, and when the motor 2 is stopped, all the oil O in the motor containing portion 61 may move to the gear containing portion 62 through the connection hole 68. A part of the oil O supplied to the inside of the motor housing portion 61 through the oil passage 90 described later may be left in the inside of the motor housing portion 61 in a state where the motor 2 is stopped.

The oil O circulates in an oil passage 90 described later. The oil O is used for lubrication of the reduction gear unit 4 and the differential unit 5. Furthermore, the oil O is used for cooling of the motor 2. As the oil O, in order to function as lubricating oil and cooling oil, oil equivalent to lubricating oil for automatic transmission (ATF: automatic Transmission Fluid) having a low viscosity is preferably used.

In the present embodiment, the motor 2 is an inner rotor type motor. The motor 2 has both a function as a power source of the driving device 1 and a function as a power generation device. In the following description, a state in which the motor 2 drives the vehicle as a power source is referred to as a drive mode, and a state in which the motor 2 generates electricity as a power generation device is referred to as a regeneration mode. The motor 2 has a rotor 20 and a stator 30.

The rotor 20 is rotatable about a rotation axis J1 extending in the horizontal direction. The rotor 20 includes a motor shaft 21 and a rotor body 24. The rotor body 24 is fixed to the motor shaft 21. Although not shown, the rotor main body 24 has a rotor core portion fixed to the outer peripheral surface of the motor shaft 21 and a rotor magnet fixed to the rotor core portion. The torque of the rotor 20 is transmitted to the gear portion 3.

The motor rotation shaft 21 extends in the axial direction about the rotation axis J1. The motor rotation shaft 21 rotates about the rotation axis J1. The motor shaft 21 extends across the inside of the motor housing 61 and the inside of the gear housing 62. The left side portion of the motor rotation shaft 21 protrudes toward the inside of the gear housing portion 62. The motor shaft 21 has a first shaft 21a and a second shaft 21b.

In the present embodiment, the motor shaft 21 is configured by axially connecting the first shaft 21a and the second shaft 21b. In the present embodiment, the first rotation shaft 21a and the second rotation shaft 21b are hollow rotation shafts internally connected to each other. The inside of the first rotating shaft 21a and the inside of the second rotating shaft 21b are penetrated by the oil O. That is, the first shaft 21a has an oil passage portion 21c inside. The second rotary shaft 21b has an oil passage portion 21d inside.

The first shaft 21a is a shaft fixed to the rotor body 24. More specifically, the rotor body 24 is fixed to the outer peripheral surface of the first rotating shaft 21 a. The first shaft 21a is accommodated in the motor accommodating portion 61. The first shaft 21a is rotatably supported at both axial end portions by a first bearing 27a and a third bearing 27 c. That is, in the present embodiment, the bearing 27 includes the first bearing 27a and the third bearing 27c as bearings that rotatably support both axial end portions of the first shaft 21 a. As shown in fig. 2, the left end of the first rotation shaft 21a is located inside the first holding portion 66 a. The left end surface of the first rotation shaft 21a faces the inside of the reservoir 66c in the axial direction.

As shown in fig. 4, the first rotating shaft 21a has a splined hole portion 28. In the present embodiment, the spline hole portion 28 is recessed from the left end portion of the first rotation shaft 21a toward the right. The spline hole 28 is, for example, a circular hole centered on the rotation axis J1. The inside of the splined bore portion 28 is the inside at the end portion on the left side of the first rotation shaft 21 a. The splined bore portion 28 extends in an axial direction. The splined bore portion 28 opens to both sides in the axial direction.

The spline hole 28 has a plurality of internal teeth 28a on the inner peripheral surface. The plurality of internal tooth portions 28a protrude radially inward. The plurality of internal tooth portions 28a extend in the axial direction. The plurality of internal teeth portions 28a are arranged at intervals in the circumferential direction. The plurality of internal teeth portions 28a are arranged at equal intervals over the entire circumference, for example, along the circumferential direction. The left end of the internal tooth portion 28a is located at a position separated to the right from the left end of the inner peripheral surface of the splined hole portion 28.

As shown in fig. 2, the first shaft 21a has an enlarged diameter portion 22 having an enlarged inner diameter. The inner diameter of the expanded diameter portion 22 is larger than the inner diameter of the portion of the first rotating shaft 21a located on both sides in the axial direction of the expanded diameter portion 22. The enlarged diameter portion 22 is located to the right of the splined bore portion 28. The inside of the expanded diameter portion 22 is connected to the inside of the splined hole portion 28. The inner peripheral surface 22a of the expanded diameter portion 22 has a tapered surface 22b and a cylindrical surface 22c.

The tapered surface 22b is a left side portion of the inner peripheral surface 22 a. The left end of the tapered surface 22b is connected to the right end of the inner peripheral surface of the splined hole portion 28. The tapered surface 22b is centered on the rotation axis J1. The inner diameter of the tapered surface 22b increases from the left side toward the right side. The cylindrical surface 22c is connected to the right side of the tapered surface 22 b. The cylindrical surface 22c is a right side portion of the inner circumferential surface 22 a. The cylindrical surface 22c is centered on the rotation axis J1.

As shown in fig. 1, the first rotating shaft 21a has a through hole 23 penetrating from the inner peripheral surface to the outer peripheral surface of the first rotating shaft 21 a. The through hole 23 extends in the radial direction and connects the inside of the first shaft 21a with the outside of the first shaft 21 a. As shown in fig. 2, the through hole 23 includes a through hole 23a penetrating from the inner peripheral surface to the outer peripheral surface of the expanded diameter portion 22. The through holes 23a are provided in plurality along the circumferential direction. The through holes 23a are provided with two, for example.

A part of the oil O passing through the oil passage portion 21c of the first rotary shaft 21a flows out from the through hole 23a to the outside of the first rotary shaft 21 a. The oil O flowing out of the through hole 23a is ejected radially outward of the rotor 20 through the inside of the rotor body 24, for example, and is supplied to the stator 30. That is, in the present embodiment, the through hole 23a is a hole for supplying the oil O to the stator 30. Thereby, the stator 30 can be cooled by the oil O.

As shown in fig. 1, the second rotation shaft 21b is located on the left side of the first rotation shaft 21 a. The second rotation shaft 21b is a rotation shaft having one side connected to the first rotation shaft 21a and the other side connected to the gear portion 3. In the present specification, the "one side of the second rotating shaft is connected to the first rotating shaft and the other side is connected to the gear portion" may be any portion of the second rotating shaft connected to the gear portion that is located at a position axially farther from the first rotating shaft than a portion of the second rotating shaft connected to the first rotating shaft. That is, in the present embodiment, "one side of the second rotation shaft 21b is connected to the first rotation shaft 21a and the other side is connected to the gear portion 3" is only required as long as the portion of the second rotation shaft 21b connected to the gear portion 3 is located on the left side of the portion of the second rotation shaft 21b connected to the first rotation shaft 21 a. In the present embodiment, the right end of the second shaft 21b is connected to the left end of the first shaft 21 a. The axial center portion of the second rotating shaft 21b is connected to the gear portion 3.

The second rotating shaft 21b is accommodated in the gear accommodating portion 62. The second rotating shaft 21b is rotatably supported at both axial end portions by a second bearing 27b and a fourth bearing 27 d. That is, in the present embodiment, the bearing 27 includes the second bearing 27b and the fourth bearing 27d as bearings that rotatably support both axial end portions of the second rotating shaft 21 b. As shown in fig. 2, the right end portion of the second rotating shaft 21b protrudes toward the inside of the motor housing portion 61 through the hole portion 66.

As shown in fig. 5, the second rotating shaft 21b has a spline rotating shaft portion 26. In the present embodiment, the spline shaft portion 26 is the right-side end portion of the second rotation shaft 21 b. The spline shaft portion 26 extends in the axial direction. As shown in fig. 2, in the present embodiment, the second rotating shaft 21b is a hollow rotating shaft, and therefore, the spline rotating shaft portion 26 is hollow in the entire axial direction. That is, the spline shaft portion 26 has a hollow portion 26d extending in the axial direction. In the present embodiment, the hollow portion 26d constitutes the entire axial direction of the spline shaft portion 26. The interior of the hollow portion 26d constitutes a part of the oil passage portion 21 d. The spline shaft portion 26 is fitted in the spline hole portion 28. A gap 29 between the outer peripheral surface of the spline shaft portion 26 and the inner peripheral surface of the spline hole portion 28 opens in the first shaft 21 a. The gap 29 between the outer peripheral surface of the spline shaft portion 26 and the inner peripheral surface of the spline hole portion 28 opens in the reservoir portion 66 c.

As shown in fig. 5, the spline shaft portion 26 has a plurality of external teeth portions 26a on the outer peripheral surface. The plurality of external teeth portions 26a protrude radially outward. The plurality of external teeth portions 26a extend in the axial direction. The plurality of external teeth portions 26a are arranged at intervals in the circumferential direction. The plurality of external teeth portions 26a are arranged at equal intervals over the entire circumference, for example, along the circumferential direction. In the present embodiment, the number of teeth of the external tooth portion 26a is the same as the number of teeth of the internal tooth portion 28 a.

As shown in fig. 6, the plurality of internal tooth portions 28a intermesh with the plurality of external tooth portions 26 a. Thereby, in the drive mode, the rotation of the first rotating shaft 21a about the rotation axis J1 is transmitted to the second rotating shaft 21b via the plurality of internal teeth portions 28a and the plurality of external teeth portions 26 a. Further, in the regeneration mode, the rotation of the second rotating shaft 21b about the rotation axis J1 is transmitted to the first rotating shaft 21a via the plurality of internal teeth portions 28a and the plurality of external teeth portions 26 a.

The outer tooth portions 26a adjacent in the circumferential direction are spaced apart from each other by a distance larger than the size of the inner tooth portion 28a in the circumferential direction. The interval between the inner tooth portions 28a adjacent in the circumferential direction is larger than the size of the outer tooth portion 26a in the circumferential direction. Therefore, a gap 70 is provided between the external tooth portion 26a and the internal tooth portion 28 a. The gaps 70 are provided in plurality at intervals along the circumferential direction. As shown in fig. 2, the gaps 70 between the external teeth portions 26a and the internal teeth portions 28a in the circumferential direction extend in the axial direction. The gap 70 is a part of the gap 29 between the outer peripheral surface of the spline shaft portion 26 and the inner peripheral surface of the spline hole portion 28. The gap 70 is open toward both sides in the axial direction. The gap 70 has an opening 70a that opens in the first shaft 21a. The opening 70a is the right end of the gap 70. In the present embodiment, the opening 70a opens into the expanded diameter portion 22.

The gap 70 has an opening 70b that opens into the splined hole 28. The opening 70b is the left end of the gap 70. The opening 70b opens inside the spline hole 28 on the left side of the internal tooth 28 a. The opening 70b is connected to the inside of the reservoir 66c via the inside of the spline hole 28. Thereby, the inside of the expanded diameter portion 22 and the inside of the reservoir portion 66c are connected via the gap 70.

The spline shaft portion 26 has a supply hole 26b penetrating from the inner peripheral surface to the outer peripheral surface of the hollow portion 26 d. In the present embodiment, a plurality of supply holes 26b are provided along the circumferential direction of the spline shaft portion 26. The supply holes 26b are provided with two, for example. The two supply holes 26b are arranged to sandwich the rotation axis J1 in the radial direction. As shown in fig. 5, the supply hole 26b is, for example, a circular hole. In the present embodiment, the supply hole 26b is located at the axial center portion in the spline shaft portion 26. The radially outer end of the supply hole 26b is formed by cutting away a part of the external tooth portion 26a, for example. As shown in fig. 2, the radially outer end of the supply hole 26b opens at a gap 29 between the outer peripheral surface of the spline shaft portion 26 and the inner peripheral surface of the spline hole portion 28. That is, the supply hole 26b is connected to the gap 29. In the present embodiment, the supply hole 26b is connected to the gap 70 between the external tooth portion 26a and the internal tooth portion 28a in the gap 29.

The radially outer end of the supply hole 26b may be provided at a portion of the outer peripheral surface of the spline shaft portion 26 where the external tooth portion 26a is not provided. The portion of the outer peripheral surface of the spline shaft portion 26 where the external tooth portions 26a are not provided means, for example, a portion of the outer peripheral surface of the spline shaft portion 26 between the circumferentially adjacent external tooth portions 26a. In this case, the external teeth portion 26a is not cut out by the supply hole 26 b.

As shown in fig. 5, the spline shaft portion 26 has an annular supply path 26c. The supply passage 26c is provided on the entire outer peripheral surface of the spline shaft portion 26. The supply path 26c is, for example, annular with the rotation axis J1 as the center. In the present embodiment, the supply passage 26c is an annular groove that opens radially outward. The supply passage 26c is recessed radially inward of the outer peripheral surface between the outer teeth 26a adjacent in the circumferential direction in the spline shaft portion 26. The supply passage 26c is located at an axial central portion in the outer peripheral surface of the spline shaft portion 26.

The supply passage 26c circumferentially penetrates all of the plurality of external teeth portions 26a. All the external teeth 26a are axially interrupted by the supply passage 26c. The circumferentially adjacent external teeth portions 26a are connected to each other via a supply path 26c. An end portion of the supply passage 26c radially outside the supply hole 26b is provided midway in the supply passage 26c. Thereby, the supply passage 26c is connected to the supply hole 26 b. In the present embodiment, the width of the supply passage 26c in the axial direction is smaller than the inner diameter of the supply hole 26 b.

As shown in fig. 1, the stator 30 faces the rotor 20 with a gap therebetween in the radial direction. In more detail, the stator 30 is located radially outside the rotor 20. The stator 30 surrounds the rotor 20. The stator 30 has a stator core 32 and a coil assembly 33. The stator core 32 is fixed to the inner peripheral surface of the motor housing portion 61. Although not shown, the stator core 32 has: a cylindrical core back extending in the axial direction; and a plurality of pole teeth extending radially inward from the core back. The plurality of pole teeth are arranged at equal intervals along the circumferential direction over the entire circumference.

The coil assembly 33 has a plurality of coils 31 mounted to the stator core 32 in the circumferential direction. The plurality of coils 31 are mounted on the respective pole teeth of the stator core 32 via insulation members, not shown. The plurality of coils 31 are arranged along the circumferential direction. More specifically, the plurality of coils 31 are arranged at equal intervals over the entire circumference along the circumferential direction. Although not shown, the coil assembly 33 may have a binding member or the like for binding the coils 31, or may have a jumper wire for connecting the coils 31 to each other.

The coil assembly 33 has coil ends 33a, 33b protruding in the axial direction from the stator core 32. The coil ends 33a are portions protruding to the right from the stator core 32. The coil end 33b is a portion protruding leftward from the stator core 32. The coil end 33a includes a portion of each coil 31 included in the coil assembly 33 protruding toward the right side of the stator core 32. The coil end 33b includes a portion of each coil 31 included in the coil assembly 33 protruding toward the left side of the stator core 32. The coil ends 33a and 33b are, for example, annular with the rotation axis J1 as the center. Although not shown, the coil ends 33a and 33b may include a binding member or the like for binding the coils 31, or may include a jumper wire for connecting the coils 31 to each other.

The plurality of bearings 27 rotatably support the motor shaft 21. The first bearing 27a and the third bearing 27c are bearings that support the first rotating shaft 21a rotatably. The second bearing 27b and the fourth bearing 27d are bearings that support the second rotating shaft 21b rotatably. The first bearing 27a and the second bearing 27b are held by the partition wall portion 63. The third bearing 27c is held by a cover member 61b in the motor housing portion 61, the cover member 61b covering the right sides of the rotor 20 and the stator 30. The fourth bearing 27d is held by the wall portion on the left side of the gear housing portion 62.

The first bearing 27a, the second bearing 27b, the third bearing 27c and the fourth bearing 27d are, for example, ball bearings. That is, each bearing 27 has an inner ring, an outer ring located radially outward of the inner ring, and a plurality of balls located radially between the inner ring and the outer ring. The inner ring of each bearing 27 is fitted and fixed to the outer peripheral surface of the motor shaft 21.

Here, the ball bearing assembled in a fixed-position pre-compression manner is fixed in a state in which the outer race is axially offset from the inner race according to a pre-measured dimension. This can suppress the outer race from rocking with respect to the inner race, and can improve the accuracy of the rotation support. In this case, when the clearance between the inner ring and the outer ring with respect to the balls is set to zero, the load applied to the balls may become large due to expansion caused by heat generation at the time of use, and the life of the ball bearing may be significantly reduced. Therefore, in the case where the ball bearing is subjected to the fixed-position pre-compression, the inner ring and the outer ring are assembled with a slight gap provided in relation to the inner ring, the balls, and the outer ring. In the assembled ball bearing, the outer race is axially movable relative to the inner race by the amount of the gap. In this specification, the gap is referred to as a retention gap. In other words, the outer race is allowed to move relative to the inner race by the amount of the clearance.

Therefore, the motor shaft 21 supported by the bearings 27 of the present embodiment can move the amount of the clearance left by the bearings 27 in the axial direction. More specifically, the first shaft 21a can axially move the amount of the clearance left by the first bearing 27a and the third bearing 27 c. The second rotation shaft 21b can axially move the amount of the clearance between the second bearing 27b and the fourth bearing 27 d.

The gear portion 3 is accommodated in the gear accommodating portion 62 of the housing 6. The gear portion 3 is connected to the motor shaft 21. More specifically, the gear portion 3 is connected to the left end of the motor shaft 21. The gear portion 3 has a reduction gear 4 and a differential gear 5. The torque output from the motor 2 is transmitted to the differential 5 via the reduction gear 4.

The reduction gear 4 is connected to the motor 2. The reduction gear 4 reduces the rotational speed of the motor 2, and increases the torque output from the motor 2 according to the reduction gear ratio. The reduction gear 4 transmits the torque output from the motor 2 to the differential 5. The reduction gear 4 has a first helical gear portion 41, a second helical gear portion 42, a third helical gear portion 43, and an intermediate rotary shaft 45. That is, the gear portion 3 has a first helical gear portion 41, a second helical gear portion 42, a third helical gear portion 43, and an intermediate rotary shaft 45.

The first helical gear portion 41 is connected to the outer peripheral surface of the second rotating shaft 21 b. As shown in fig. 5, the first helical gear portion 41 is integrally formed with the second rotating shaft 21b, for example. The first helical gear portion 41 may be formed separately from the second rotating shaft 21b and fixed to the outer peripheral surface of the second rotating shaft 21 b. The first helical gear portion 41 rotates together with the motor shaft 21 about the rotation axis J1.

As shown in fig. 1, the intermediate rotary shaft 45 extends along an intermediate axis J2 parallel to the rotation axis J1. The intermediate rotary shaft 45 rotates about the intermediate axis J2. The second helical gear portion 42 and the third helical gear portion 43 are fixed to the outer peripheral surface of the intermediate rotary shaft 45. The second bevel gear portion 42 and the third bevel gear portion 43 are connected via an intermediate rotary shaft 45. The second bevel gear portion 42 and the third bevel gear portion 43 rotate about the intermediate axis J2. The second helical gear portion 42 meshes with the first helical gear portion 41. The third bevel gear portion 43 meshes with a ring gear 51 of the differential device 5, which will be described later.

The torque output from the motor 2 is transmitted to the ring gear 51 of the differential device 5 via the motor rotation shaft 21, the first helical gear portion 41, the second helical gear portion 42, the intermediate rotation shaft 45, and the third helical gear portion 43 in this order. The gear ratio of each gear, the number of gears, and the like can be variously changed according to the reduction ratio required. In the present embodiment, the reduction gear 4 is a parallel shaft gear type reduction gear in which the shaft cores of the gears are arranged in parallel.

The differential device 5 is connected to the motor 2 via the reduction device 4. The differential device 5 is a device for transmitting torque output from the motor 2 to wheels of the vehicle. The differential device 5 absorbs the speed difference between the left and right wheels when the vehicle turns, and transmits the same torque to the axles 55 of the left and right wheels. As described above, in the present embodiment, the gear portion 3 transmits the torque of the motor 2 to the axle 55 of the vehicle via the reduction gear 4 and the differential gear 5. Thereby, the drive device 1 rotates the axle 55 of the vehicle.

The differential device 5 has a ring gear 51, a gear housing not shown, a pair of pinion gears not shown, a pinion gear shaft not shown, and a pair of side gears not shown. The ring gear 51 rotates about a differential axis J3 parallel to the rotation axis J1. The torque output from the motor 2 is transmitted to the ring gear 51 via the reduction gear 4.

The motor 2 is provided with an oil passage 90 through which the oil O circulates inside the housing 6. The oil passage 90 is a path for supplying the oil O from the oil reservoir P to the motor 2 and guiding the oil O to the oil reservoir P again. The oil passage 90 extends between the inside of the motor housing 61 and the inside of the gear housing 62.

In the present specification, the "oil passage" refers to a path of oil. Therefore, the concept of the "oil passage" includes not only a "flow passage" that forms a flow of oil always in one direction, but also a path that temporarily stagnates oil and a path through which oil supply drops. The path for temporarily retaining the oil includes, for example, a reservoir for storing the oil.

The oil passage 90 has a first oil passage 91 and a second oil passage 92. The first oil passage 91 and the second oil passage 92 circulate the oil O inside the housing 6, respectively. The first oil passage 91 has a lift path 91a, a shaft supply path 91b, a shaft inner path 91c, and a rotor inner path 91d. Further, a first reservoir 93 is provided in the path of the first oil passage 91. The first storage portion 93 is provided in the gear housing portion 62.

The lifting path 91a is a path for lifting the oil O from the oil reservoir P by rotation of the ring gear 51 of the differential device 5 and receiving the oil O at the first reservoir 93. The first storage portion 93 is opened toward the upper side. The first reservoir 93 receives the oil O lifted by the ring gear 51. When the liquid surface S of the oil reservoir P is high immediately after the motor 2 is driven, the first reservoir 93 receives the oil O lifted by the ring gear 51, and also receives the oil O lifted by the second bevel gear 42 and the third bevel gear 43. The storage unit 93 further includes: an oil supply hole 93a, the oil supply hole 93a supplying oil O to the first bearing 27a or the second bearing 27b; and an oil supply hole 93b, the oil supply hole 93b supplying the oil O to the fourth bearing 27d.

The shaft supply path 91b guides the oil O from the first reservoir 93 to the oil passage portion 21d of the second shaft 21 b. The in-shaft path 91c is a path through which the oil O passes inside the motor shaft 21. The spindle inner path 91c is constituted by the oil passage portion 21d and the oil passage portion 21 c. In the motor shaft 21, the oil O flows from the left side to the right side. That is, the oil O flowing in the motor shaft 21 flows from the inside of the second shaft 21b to the inside of the first shaft 21 a. The rotor inner path 91d is a path that passes through the inside of the rotor body 24 from the through hole 23 of the motor shaft 21 and is scattered to the stator 30.

In the in-shaft path 91c, centrifugal force is applied to the oil O inside the rotor 20 in accordance with the rotation of the rotor 20. Thereby, the oil O continuously flies from the rotor 20 to the radial outside. In addition, the path inside the rotor 20 becomes negative pressure with the scattering of the oil O, and the oil O stored in the first storage 93 is sucked toward the inside of the rotor 20, thereby filling the path inside the rotor 20 with the oil O.

The oil O reaching the stator 30 takes heat from the stator 30. The oil O cooled by the stator 30 is dropped downward and accumulated in a lower region in the motor housing 61. The oil O accumulated in the lower region of the motor housing 61 moves to the gear housing 62 through the connection hole 68 provided in the partition wall 63. As described above, the first oil passage 91 supplies the oil O to the rotor 20 and the stator 30.

As shown in fig. 2, a part of the oil O passing through the spindle inner path 91c is supplied to the gap 70 between the external tooth portion 26a and the internal tooth portion 28a via the supply hole 26 b. As a result, as shown in fig. 6, the drive device 1 has oil O at the gap 70 between the external tooth portion 26a and the internal tooth portion 28 a. A part of the oil O supplied to the gap 70 flows out to the reservoir 66c, for example. Thereby, the oil O is stored in the storage portion 66c.

In addition, according to the present embodiment, the oil O flowing into the pipe 10 disposed in the motor housing 61 flows in the pipe 10, and is supplied to the stator 30 from the oil supply hole provided in the pipe 10. The supplied oil O is scattered by the stator 30 or the rotor 20, and a part of the scattered oil O adheres to the partition wall 63. The adhering oil O is transferred at the partition wall 63, and is immersed in the motor-side opening 67a of the communication hole 67, and is supplied to the reservoir 66c. Thereby, the oil O is stored in the storage portion 66c. In addition, the oil O reaching the stator 30 takes heat from the stator 30. The oil O that does not flow into the communication hole 67 drops downward and is accumulated in the lower region of the motor housing 61. The oil O stored in the lower region of the motor housing 61 moves to the oil reservoir P of the gear housing 62 through the connection hole 68 provided in the partition wall 63.

In the present specification, the "drive device has oil at the gap between the external teeth portion and the internal teeth portion" is not limited to this, as long as the oil is located at the gap between the external teeth portion and the internal teeth portion in at least a part of the motor driving process. In the present specification, the "drive device has oil at the gap between the external gear and the internal gear" is only required to have oil at least one of the gaps between the external gear and the internal gear. That is, in the present embodiment, the oil O may be absent in some of the gaps 70 among the plurality of gaps 70.

As shown in fig. 1, in the second oil passage 92, the oil O is lifted from the oil reservoir P and supplied to the stator 30. The second oil passage 92 is provided with an oil pump 96, a cooler 97, and the pipe 10. The second oil passage 92 has a first flow path 92a, a second flow path 92b, a third flow path 92c, and a fourth flow path 94.

The first flow path 92a, the second flow path 92b, and the third flow path 92c are provided in a wall portion of the housing 6. The first flow path 92a connects the oil reservoir P with the oil pump 96. The second flow path 92b connects the oil pump 96 with the cooler 97. The third flow path 92c connects the cooler 97 with the fourth flow path 94. The fourth flow channel 94 is provided in the partition wall 63. The fourth flow path 94 connects the third flow path 92c with the inside of the pipe 10. The pipe 10 extends in the axial direction. The pipe 10 is located radially outside the stator 30. The pipe 10 has: oil supply holes for supplying oil to the coil ends 33a, 33 b; and an oil supply hole that supplies oil to the stator core 32. Although not shown, the duct 10 is provided in plurality, for example.

The oil pump 96 is a pump that delivers oil O as a refrigerant. In the present embodiment, the oil pump 96 is an electric pump driven electrically. The oil pump 96 sucks up the oil O from the oil reservoir P through the first flow path 92a, and supplies the oil O to the motor 2 through the second flow path 92b, the cooler 97, the third flow path 92c, the fourth flow path 94, and the pipe 10. The oil O flowing into the pipe 10 flows rightward in the pipe 10 and is supplied to the stator 30 from an oil supply hole provided in the pipe 10. Thus, the oil O can be supplied from the pipe 10 to the stator 30, and the stator 30 can be cooled. The oil O supplied from the pipe 10 to the stator 30 drops downward and is accumulated in a lower region in the motor housing 61. The oil O stored in the lower region of the motor housing 61 moves to the oil reservoir P of the gear housing 62 through the connection hole 68 provided in the partition wall 63. As described above, the second oil passage 92 supplies the oil O to the stator 30.

The cooler 97 cools the oil O passing through the second oil passage 92 b. The second flow path 92b and the third flow path 92c are connected to the cooler 97. The second flow path 92b and the third flow path 92c are connected via an internal flow path of the cooler 97. A cooling water pipe 98 is connected to the cooler 97, and the cooling water pipe 98 is passed through by cooling water cooled by a radiator, not shown. The oil O passing through the inside of the cooler 97 is cooled by exchanging heat with the cooling water passing through the cooling water pipe 98.

When the driving device 1 is in the driving mode, the rotation of the first shaft 21a is transmitted to rotate the second shaft 21 b. On the other hand, when the drive device 1 is in the regenerative mode, the rotation of the second rotating shaft 21b is transmitted to the first rotating shaft 21a. When the mode of the motor 2 is switched, the circumferential surface of the external tooth portion 26a that contacts the internal tooth portion 28a is switched.

Specifically, for example, as shown in fig. 6, when the drive device 1 is in the drive mode, the surface on one circumferential side of the internal tooth portion 28a contacts the surface on the other circumferential side of the external tooth portion 26 a. Here, the circumferential direction side is the side toward which the arrow θ faces. The other side in the circumferential direction is the opposite side to the side toward which the arrow θ faces. In this case, the direction of the arrow θ is the direction in which the motor rotation shaft rotates.

In this case, when the drive device 1 is switched from the drive mode to the regeneration mode, the external teeth portion 26a relatively moves with respect to the internal teeth portion 28a in the circumferential direction indicated by the open arrow in fig. 6. In the regeneration mode, the first shaft 21a is rotated by the rotation of the second shaft 21b in a state where the surface on one side in the circumferential direction of the external tooth portion 26a is in contact with the surface on the other side in the circumferential direction of the internal tooth portion 28 a. Thus, the motor 2 functions as an engine.

Further, when the drive device 1 is switched from the regeneration mode to the drive mode, the first rotation shaft 21a is rotated by the motor 2, and therefore, the first rotation shaft 21a is rotated relative to the second rotation shaft 21b toward the circumferential direction side. As a result, the internal tooth portion 28a moves relative to the external tooth portion 26a in the circumferential direction, and the external tooth portion 26a contacts the internal tooth portion 28a in the state shown in fig. 6. Thus, the rotation of the first rotation shaft 21a is transmitted to the second rotation shaft 21b.

When the driving device 1 is in the driving mode, a torque in the same direction as the direction in which the first shaft 21a rotates is applied to the second shaft 21b and the gear portion 3. On the other hand, when the drive device 1 is in the regenerative mode, the motor 2 functions as a regenerative brake for decelerating the rotation of the wheels. Therefore, a torque opposite to the direction in which the first shaft 21a rotates is applied at the second shaft 21b and the gear portion 3. Thereby, when the mode of the driving device 1 is switched between the driving mode and the regenerating mode, the direction of the torque applied to the second rotating shaft 21b is reversed.

Here, in the present embodiment, the gear portion 3 has a first helical gear portion 41 connected to the outer peripheral surface of the second rotating shaft 21b. Therefore, at the second rotating shaft 21b, stress on one axial side or the other axial side is applied according to the application direction of the torque. Thus, when the mode of the drive device 1 is switched and the direction of torque application is reversed, the second rotating shaft 21b moves the amount of the remaining gap of the second bearing 27b and the fourth bearing 27d in the axial direction. Therefore, an axial load may be applied to the bearing 27 supporting the second rotating shaft 21b due to the axial movement of the second rotating shaft 21b.

On the other hand, the first rotation shaft 21a is connected to the second rotation shaft 21b by spline coupling. Thus, the relative movement of the first rotation shaft 21a and the second rotation shaft 21b in the axial direction is substantially allowed. Thus, even if the second rotation shaft 21b moves in the axial direction, the axial force is not easily transmitted to the first rotation shaft 21a. However, in a state where the motor shaft 21 rotates and the spline-coupled external tooth portion 26a and the internal tooth portion 28a are strongly engaged, for example, an axial end portion of the external tooth portion 26a is engaged with an inner peripheral surface of the spline hole portion 28, and the axial force applied to the second shaft 21b may be transmitted to the first shaft 21a. Accordingly, the first rotating shaft 21a may axially move along with the axial movement of the second rotating shaft 21b, so that an axial load is applied to the bearing 27 that rotatably supports the first rotating shaft 21a.

In addition, at the time of mode switching of the driving device 1, the direction of the axial direction in which the second rotating shaft 21b moves differs depending on the skew direction of the teeth of the first helical gear portion 41 and the skew direction of the teeth of the second helical gear portion 42. For example, when the drive device 1 is switched from the drive mode to the regeneration mode, the second rotation shaft 21b moves in the axial direction in a direction approaching the first rotation shaft 21a. On the other hand, for example, when the drive device 1 is switched from the regeneration mode to the drive mode, the second rotation shaft 21b moves in the axial direction in a direction away from the first rotation shaft 21a. Further, the second rotation shaft 21b may be configured to move in the axial direction in a direction away from the first rotation shaft 21a when the drive device 1 is switched from the drive mode to the regeneration mode, and the second rotation shaft 21b may be configured to move in the axial direction in a direction closer to the first rotation shaft 21a when the drive device 1 is switched from the regeneration mode to the drive mode.

When the second rotating shaft 21b moves in the axial direction in the direction approaching the first rotating shaft 21a, the axial end portions of the external tooth portions 26a are easily engaged with the inner peripheral surface of the spline hole portion 28, and the axial movement of the second rotating shaft 21b is easily transmitted to the first rotating shaft 21a. On the other hand, when the second rotating shaft 21b moves in a direction away from the first rotating shaft 21a, the axial end portions of the external teeth portions 26a are less likely to engage with the inner peripheral surface of the spline hole portion 28, and the axial movement of the second rotating shaft 21b is less likely to be transmitted to the first rotating shaft 21a. That is, when the second rotating shaft 21b moves in the axial direction in the direction approaching the first rotating shaft 21a, the possibility that the axial load is applied to the bearing 27 supporting the first rotating shaft 21a is easily increased.

In addition, the present inventors have recently found that there is a possibility that the first rotation shaft 21a is also moved in the axial direction along with the axial movement of the second rotation shaft 21b, and particularly when the second rotation shaft 21b is moved in the axial direction in a direction approaching the first rotation shaft 21a, there is a high possibility that the first rotation shaft 21a is also moved in the axial direction.

In response to the above, according to the present embodiment, in the drive device 1, the oil O flowing into the pipe 10 disposed in the motor housing 61 flows in the pipe 10, and is supplied to the stator 30 from the oil supply hole provided in the pipe 10. The supplied oil O is scattered by the stator 30 or the rotor 20, and a part of the scattered oil O adheres to the partition wall 63. The adhering oil O is transferred at the partition wall 63 and flows into the motor-side opening 67a of the communication hole 67, and is supplied to the reservoir 66c. Thus, by taking in the oil O supplied into the motor housing portion 61, the oil O can be supplied to the reservoir portion 66c. Thereby, the oil O is stored in the storage portion 66c. Therefore, the drive device 1 can supply the oil O from the reservoir 66c to the gap 70 between the external tooth portion 26a and the internal tooth portion 28a forming the spline joint. That is, the drive device 1 has the oil O at the gap 70 between the external gear portion 26a and the internal gear portion 28 a. Therefore, the oil O functions as damping, and the relative speed at which the external tooth portion 26a and the internal tooth portion 28a come close to each other at the time of mode switching can be reduced. For example, when the drive mode is switched to the regeneration mode and the surface on one side in the circumferential direction of the external tooth portion 26a is close to the surface on the other side in the circumferential direction of the internal tooth portion 28a as indicated by the hollow arrow in fig. 6, the external tooth portion 26a and the internal tooth portion 28a relatively gradually approach each other while pushing out the oil O from the gap 70 because the oil O is present in the gap 70. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved.

This can lengthen the time required for the mode switching to the time required for the external tooth portion 26a to make reverse meshing contact with the internal tooth portion 28 a. Therefore, the second rotating shaft 21b can be moved relative to the first rotating shaft 21a in the axial direction until the external tooth portions 26a and the internal tooth portions 28a are strongly engaged. Therefore, at the time of mode switching, the application of the axial force from the second rotation shaft 21b to the first rotation shaft 21a can be suppressed, and the axial movement of the first rotation shaft 21a can be suppressed. Therefore, the axial loads applied to the first bearing 27a and the third bearing 27c supporting the first rotating shaft 21a can be suppressed. In particular, the generation of abrupt loads at the first bearing 27a and the third bearing 27c can be suppressed. Thus, smaller bearings that are resistant to smaller loads can be employed as the first bearing 27a and the third bearing 27c.

Further, when the second rotating shaft 21b moves in the axial direction, the oil O also functions as lubricating oil so that the second rotating shaft 21b can easily slide in the axial direction. Further, the oil O can also function as damping by the viscosity of the oil O with respect to the axial movement of the second rotating shaft 21 b. Therefore, the speed at which the second rotating shaft 21b moves in the axial direction can also be reduced. Thus, when the second rotating shaft 21b moves in the axial direction, the axial loads applied to the second bearing 27b and the fourth bearing 27d that support the second rotating shaft 21b can be suppressed. Particularly, the occurrence of abrupt load at the second bearing 27b and the fourth bearing 27d can be suppressed. Therefore, smaller and less load-resistant bearings can be employed as the second bearing 27b and the fourth bearing 27d.

As described above, according to the present embodiment, the axial load applied to the plurality of bearings 27 can be suppressed. As in the present embodiment, the above-described effects are particularly useful in a configuration in which the plurality of bearings 27 includes a bearing 27 that rotatably supports both axial ends of the first rotating shaft 21a and a bearing that rotatably supports both axial ends of the second rotating shaft 21 b.

The axial movement of the second rotating shaft 21b may be performed entirely or only partially until the external teeth 26a and the internal teeth 28a are in reverse meshing contact at the time of mode switching of the drive device 1. That is, the second rotating shaft 21b may be moved in the axial direction by a portion of the clearance before the external teeth portion 26a and the internal teeth portion 28a are brought into reverse-meshing contact at the time of mode switching, and the second rotating shaft 21b may be moved in the axial direction by the remaining amount of the clearance after the external teeth portion 26a and the internal teeth portion 28a are brought into contact. Even in this case, the external tooth portions 26a and the internal tooth portions 28a can be brought into contact with each other by the damping function of the oil O while relatively moving at a small speed, and therefore, the external tooth portions 26a are less likely to mesh into the inner peripheral surface of the spline hole portion 28. Thus, even after the external tooth portions 26a are in contact with the internal tooth portions 28a, the axial movement of the second rotating shaft 21b is not easily transmitted to the first rotating shaft 21a.

Further, even in the case where the axial movement of the second rotating shaft 21b is transmitted to the first rotating shaft 21a after the external tooth portion 26a contacts with the internal tooth portion 28a, the oil O can function as damping for the axial movement of the first rotating shaft 21a by the viscosity of the oil O. Therefore, the speed at which the first shaft 21a moves in the axial direction can also be reduced. Thus, even when the first rotating shaft 21a moves in the axial direction, the axial load applied to the first bearing 27a and the third bearing 27c that support the first rotating shaft 21a can be suppressed. In particular, the generation of abrupt loads at the first bearing 27a and the third bearing 27c can be suppressed.

On the other hand, when the entire axial movement of the second rotating shaft 21b is performed during the mode switching of the drive device 1 until the external tooth portion 26a and the internal tooth portion 28a are in reverse meshing contact, the axial movement of the first rotating shaft 21a can be more desirably suppressed. Therefore, the axial load applied to the bearing 27 supporting the first rotating shaft 21a can be more desirably suppressed. In particular, the occurrence of a sudden load on the bearing 27 supporting the first shaft 21a can be suppressed.

In addition, the external tooth portion 26a and the internal tooth portion 28a are not in direct contact until the external tooth portion 26a and the internal tooth portion 28a are in reverse meshing contact after the mode switching of the drive device 1. However, even in this case, the transmission of rotation between the first rotation shaft 21a and the second rotation shaft 21b can be performed via the oil O of the gap 70. Therefore, even when, for example, the drive device 1 is switched from the regenerative mode to the drive mode, the rotational torque of the first rotating shaft 21a is transmitted to the second rotating shaft 21b before the external tooth portions 26a are brought into reverse meshing contact with the internal tooth portions 28 a. Thereby, the torque applied to the second rotating shaft 21b is reversed before the external tooth portions 26a and the internal tooth portions 28a are brought into reverse meshing contact, and the second rotating shaft 21b moves in the axial direction. Therefore, even when the drive device 1 is switched from the regenerative mode to the drive mode, the axial load applied to the bearing 27 supporting the first rotating shaft 21a can be suppressed. In particular, the occurrence of a sudden load on the bearing 27 supporting the first shaft 21a can be suppressed.

Further, according to the present embodiment, the spline shaft portion 26 has a hollow portion 26d and a supply hole 26b penetrating from the inner peripheral surface to the outer peripheral surface of the hollow portion 26 d. The supply hole 26b is connected to the gap 70 between the external gear portion 26a and the internal gear portion 28 a. Therefore, by flowing the oil O inside the hollow portion 26d, the oil O passing through the hollow portion 26d can be supplied to the gap 70 via the supply hole 26b. This makes it easy to maintain the state where the oil O is present in the gap 70 between the external teeth 26a and the internal teeth 28 a. Further, by supplying the oil O from the supply hole 26b to the spline joint portion, an oil film is formed between the external tooth portion 26a and the internal tooth portion 28a of the spline joint portion. By forming the oil film, the oil O supplied from the communication hole 67 to the reservoir 66c can be retained in the reservoir 66c without leaking out from the spline joint portion. Therefore, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved.

Further, the gap 70 newly generated by bringing the external tooth portion 26a into reverse meshing contact with the internal tooth portion 28a can also be supplied with the oil O through the supply hole 26b for the mode switching of the drive device 1. Therefore, even if the mode of the drive device 1 is switched between the drive mode and the regeneration mode a plurality of times, the axial load applied to each bearing 27 can be suppressed at each switching. The newly generated gap 70 is, for example, the gap 70 generated between the surface of the external tooth portion 26a on the other side in the circumferential direction and the surface of the internal tooth portion 28a on the one side in the circumferential direction when the external tooth portion 26a moves relative to the internal tooth portion 28a on one side in the circumferential direction from the state shown in fig. 6.

Further, according to the present embodiment, the supply holes 26b are provided in plurality along the circumferential direction of the spline shaft portion 26. Therefore, the oil O is more desirably supplied to the respective gaps 70 of the external tooth portions 26a and the internal tooth portions 28a via the supply holes 26 b.

Further, according to the present embodiment, the spline shaft portion 26 has an annular supply path 26c provided on the entire periphery of the outer peripheral surface. The supply passage 26c is connected to the supply hole 26 b. Therefore, the oil O flowing out from the supply hole 26b to the outer peripheral surface of the spline shaft 26 is easily supplied to the entire circumference of the spline shaft 26 via the supply passage 26c. Thereby, the oil O is easily supplied to all of the plurality of gaps 70. Therefore, the damping function of the oil O can be more desirably obtained. Therefore, the axial load applied to each bearing 27 can be further suppressed. Particularly, the occurrence of a sudden load on each bearing 27 can be suppressed.

Further, according to the present embodiment, the supply path 26c is an annular groove. Therefore, the oil O flowing out from the supply hole 26b to the outer peripheral surface of the spline shaft portion 26 can be held in the supply passage 26c and can flow over the entire circumference. Thereby, the oil O is easily and uniformly supplied to all of the plurality of gaps 70.

Further, according to the present embodiment, the inside of the expanded diameter portion 22 and the inside of the reservoir portion 66c are connected via the gap 70 between the external tooth portion 26a and the internal tooth portion 28 a. Accordingly, the enlarged diameter portion 22 and the reservoir portion 66c, in which a large amount of oil O is easily accumulated, are disposed on both sides of the gap 70. This makes it easy to hold the oil O in the gap 70. Therefore, the damping effect of the oil O can be more desirably obtained. Therefore, the axial load applied to each bearing 27 can be further suppressed. Particularly, the occurrence of a sudden load on each bearing 27 can be suppressed.

Further, according to the present embodiment, the rotation shaft having the spline shaft portion 26 is the second rotation shaft 21b, and the rotation shaft having the spline hole portion 28 is the first rotation shaft 21a. Therefore, when the oil O flows from the inside of the second rotating shaft 21b to the inside of the first rotating shaft 21a, the oil O flows from the inside of the spline shaft portion 26 to the inside of the first rotating shaft 21a. This suppresses leakage of oil O from the gap 29 between the outer peripheral surface of the spline shaft portion 26 and the inner peripheral surface of the spline hole portion 28 to the outside of the motor shaft 21, as compared with the case where oil flows from the inside of the shaft having the spline hole portion 28 to the inside of the spline shaft portion 26. Therefore, when the oil O stored in the gear housing 62 is caused to flow inside the motor shaft 21, the oil O can be desirably caused to flow from inside the second shaft 21b to inside the first shaft 21a.

As shown in fig. 7, in the second rotating shaft 121b of the present example, the entire axial direction of the spline shaft portion 126 is constituted by the hollow portion 126d as in the above-described embodiment. As in the embodiment, the oil O passes through the hollow portion 126 d. In the hollow portion 126d, the oil O flows from the left side to the right side. In this example, the supply hole 126b and the supply path 126c are provided in a left portion of the hollow portion 126 d. That is, the supply hole 126b and the supply path 126c are provided at a portion on the upstream side in the flow direction of the oil O in the hollow portion 126 d. Therefore, the oil O supplied to the gap 70 via the supply hole 126b and the supply passage 126c is easily caused to flow in the same direction as the direction in which the oil O flows in the hollow portion 126d in the gap 70, and the oil O is easily supplied to the entire axial direction of the gap 70. Thus, the oil O can be desirably supplied to the entire gap 70.

In the present specification, "the portion of the hollow portion on the upstream side in the flow direction of the oil in the hollow portion where the supply hole and the supply passage are provided" is only required to be on the upstream side of the center of the hollow portion in the flow direction of the oil in the hollow portion where the supply hole and the supply passage are provided. In this example, the supply hole 126b and the supply path 126c are located on the left side from the axial center of the hollow portion 126 d.

The inner diameter of the supply hole 126b is equal to or smaller than the axial width of the supply channel 126 c. The inner diameter of the supply hole 126b is equal to the axial width of the supply passage 126c, for example. The supply hole 126b opens to the bottom surface of the groove of the supply path 126c as a groove. The other structure of the second rotation shaft 121b is the same as that of the second rotation shaft 21 b.

< second embodiment >

As shown in fig. 8, in the present embodiment, unlike the first embodiment, the communication hole 267 is formed with an opening in the outer peripheral surface of the partition wall 63 on the side of the gear housing 62. That is, the opening portion includes a gear-side opening 267a that opens at the gear housing portion 62. The communication hole 267 is a portion that supplies the oil O supplied into the gear housing portion 62 to the reservoir portion 66 c. The partition wall portion 63 is provided with a communication hole 267 extending in the radial direction. The communication hole 267 is a hole penetrating the partition wall 63 in the radial direction and communicating the gear housing portion 62 with the reservoir portion 66 c. More specifically, as shown in fig. 8, the communication hole 267 has: a gear-side opening 267a, the gear-side opening 267a being an opening portion located on the outer peripheral surface of the partition wall portion 63; and a reservoir-side opening 267b, the reservoir-side opening 267b being located on an inner peripheral surface of the hole 66 penetrating the partition wall 63 in the axial direction. The communication hole 267 extends straight between the gear-side opening 267a and the reservoir-side opening 267 b. The gear-side opening 267a is located above the reservoir-side opening 267b on the outer peripheral surface of the partition wall 63 and faces the gear housing 62 side. In the present embodiment, the gear-side opening 267a is located above the second bearing 27b on the outer peripheral surface of the partition wall 63. The reservoir-side opening 267b is located below the gear-side opening 267a. Further, the reservoir-side opening 267b is located on the motor housing 61 side with respect to the gear-side opening 267a. Therefore, the communication hole 267 is inclined in a direction approaching the motor housing portion 61 as going to the lower side.

As shown in fig. 8, the first bearing 27a and the second bearing 27b are configured to be separated from each other in the axial direction. A reservoir 66c is provided between the first bearing 27a and the second bearing 27 b. That is, the reservoir-side opening 267b opens at a reservoir 66c located between the first bearing 27a and the second bearing 27 b.

According to the second embodiment, the oil O lifted by the ring gear 51 through the lifting path 91a is supplied from the gear-side opening 267a to the reservoir 66c through the communication hole 267. Therefore, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28a, as in the first embodiment. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved.

In addition, a part of the oil O lifted by the gear collides with the outer peripheral surface of the partition wall 63, is transmitted to the outer peripheral surface, and is supplied from the gear-side opening 267a to the reservoir 66c through the communication hole 267. Thus, by taking in the oil O supplied into the gear housing portion 62, the oil O can be supplied to the reservoir portion 66c. Thus, as in the first embodiment, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28 a. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved.

The gear housing 62 has an oil receiving portion 299 provided in the partition wall 63, and receives the oil O. The oil receiving portion 299 is formed so as to cover the periphery of the gear-side opening 267a and to open upward. Further, the oil receiving portion 299 has an opening portion so as to face the oil supply hole 93a formed in the reservoir portion 93, and the oil receiving portion 99 communicates with the gear-side opening 267 a. The oil supply hole 93a is disposed above the oil receiving portion 299.

The oil O lifted by the ring gear 51 through the lifting path 91a is supplied to the oil receiving portion 299. The oil O in the oil receiving portion 299 is supplied from the gear-side opening 267a to the reservoir 66c through the communication hole 267. Therefore, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28a, as in the first embodiment. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved. In addition, a part of the lifted oil O collides with the outer peripheral surface of the partition wall 63, is transferred to the outer peripheral surface, is accumulated in the oil receiving portion 299, and is supplied from the gear-side opening 267a to the reservoir 66c via the communication hole 267. Thus, by taking in the oil O supplied into the gear housing portion 62, the oil O can be supplied to the reservoir portion 66c. Thus, as in the first embodiment, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28 a. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved. Further, by providing the oil receiving portion 299, the oil O in the gear housing portion 62 can be easily collected.

In a state where the rotation axis J1 is arranged in the horizontal direction, the gear housing portion 62 includes: an oil reservoir P located in a lower region in the interior of the gear housing 62; a storage portion 93, the storage portion 93 being located in an upper region in the interior of the gear housing portion 62; and an oil supply hole 93a formed in the reservoir 93 and supplying the oil O to the first bearing 27a or the second bearing 27b. The oil supply hole 93a is located above the oil receiving portion 299.

According to the present second embodiment, the oil O lifted by the ring gear 51 through the lifting path 91a is received by the storage portion 93. The oil O stored in the reservoir 93 is dropped from the oil supply hole 93a formed in the first bearing 27a and the second bearing 27b, and is supplied to the oil receiving portion 299. The oil O in the oil receiving portion 299 is supplied from the gear-side opening 267a to the reservoir 66c through the communication hole 267. Therefore, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28a, as in the first embodiment. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved. In addition, a part of the lifted oil O collides with the outer peripheral surface of the partition wall 63, is transferred to the outer peripheral surface, is accumulated in the oil receiving portion 299, and is supplied from the gear-side opening 267a to the reservoir 66c via the communication hole 267. Thus, by taking in the oil O supplied into the gear housing portion 62, the oil O can be supplied to the reservoir portion 66c. Thus, as in the first embodiment, the drive device 1 can supply the oil O to the gap 70 between the external teeth portion 26a and the internal teeth portion 28 a. Further, since the oil O is stored in the reservoir 66c, the lubricity of the first bearing 27a and the second bearing 27b can be improved. In addition, by providing the oil supply hole 93a above the oil receiving portion 299, the oil O in the gear housing portion 62 can be easily collected.

The present invention is not limited to the above-described embodiments, and other configurations may be adopted within the scope of the technical idea of the present invention. The shape and the number of the communication holes are not particularly limited. The communication hole may be provided in one or both of the gear housing portion and the motor housing portion. The first bearing may be a bearing having a larger diameter than the second bearing. In this case, the opening is preferably provided on the gear housing portion side. The number of the supply holes provided in the spline shaft portion is not particularly limited. The annular supply path provided in the spline shaft portion may be other than a groove. The supply passage may be constituted by an outer peripheral surface of a portion of the spline shaft portion located between the circumferentially adjacent external tooth portions and a hole penetrating each of the external tooth portions in the circumferential direction. The driving device may not be configured to actively supply oil to the gap between the external teeth and the internal teeth, as long as the driving device has oil at the gap between the external teeth and the internal teeth.

The spline shaft may be hollow in a part in the axial direction. The spline shaft portion may not have a hollow portion. In this case, the entire axial direction of the spline shaft portion is a solid portion. Alternatively, the first shaft may have a spline shaft portion and the second shaft may have a spline hole portion. The number of teeth of the external tooth portion may be smaller than the number of teeth of the internal tooth portion. The first and second shafts may also be solid shafts.

The bearing for supporting the motor shaft to be rotatable may not include any one of a bearing for supporting the first shaft and a bearing for supporting the second shaft. The first shaft may not be a structure in which both axial end portions are supported by bearings. The second rotating shaft may not be a structure in which both axial end portions are supported by bearings.

In the above embodiment, the case where the driving apparatus does not include the inverter unit has been described, but the present invention is not limited thereto. The drive device may also comprise an inverter unit. In other words, the driving device may be integrated with the inverter unit. The application of the driving device is not particularly limited. The driving device may not be mounted on the vehicle. The structures described in this specification can be appropriately combined within a range not contradicting each other.

Claims

1. A driving device includes:

a motor having a rotor with a motor rotation shaft rotating about a rotation axis and a rotor body fixed to the motor rotation shaft, and a stator surrounding the rotor;

the gear part is connected with the motor rotating shaft;

a plurality of bearings that rotatably support the motor shaft; and

A housing accommodating the motor and the gear portion,

the motor shaft has:

a first rotating shaft fixed to the rotor body;

one side of the second rotating shaft is connected with the first rotating shaft, and the other side of the second rotating shaft is connected with the gear part;

a spline shaft portion provided in one of the first rotating shaft and the second rotating shaft, the spline shaft portion having a plurality of external teeth portions on an outer peripheral surface;

a spline hole portion provided in the other of the first rotating shaft and the second rotating shaft, the spline hole portion being fitted with the spline shaft portion; and

a plurality of internal teeth portions provided on an inner peripheral surface of the spline hole portion, the plurality of internal teeth portions being engaged with the plurality of external teeth portions,

the housing has:

a motor housing unit configured to house the motor therein;

a gear housing portion that houses the gear portion therein;

a partition wall portion that partitions an interior of the motor housing portion from an interior of the gear housing portion; and

a storage portion that stores oil around the one rotating shaft,

The bearing includes:

a first bearing that rotatably supports the first rotation shaft; and

a second bearing rotatably supporting the second rotating shaft,

the partition wall portion has:

the storage portion;

a first holding portion that holds the first bearing inside;

a second holding portion that holds the second bearing inside; and

a communication hole that communicates one of the motor housing portion and the gear housing portion with the reservoir portion, the oil supplied to a region of one of the motor housing portion and the gear housing portion being supplied to the reservoir portion via the communication hole,

the interior of the first holding portion is connected to the interior of the second holding portion via the interior of the reservoir portion,

a first gap between the outer peripheral surface of the spline shaft portion and the inner peripheral surface of the spline hole portion is opened in the interior of the reservoir portion,

the spline shaft portion has:

a hollow portion extending in an axial direction, oil passing through the hollow portion; and

a supply hole penetrating from an inner peripheral surface to an outer peripheral surface of the hollow portion,

The supply hole is connected to a second gap between the external tooth portion and the internal tooth portion, the second gap being a part of the first gap.

2. The driving device according to claim 1, wherein,

in a state where the rotation axis is arranged in the horizontal direction, the partition wall portion has a reservoir-side opening located on an inner peripheral surface of a hole portion penetrating in the axial direction, and the reservoir-side opening is located above the motor rotation shaft.

3. The driving device according to claim 1, wherein,

the second bearing is a bearing having a larger diameter than the first bearing,

the partition wall portion has:

an opening portion that opens on an outer peripheral surface of the partition wall portion; and

a reservoir-side opening located on an inner peripheral surface of a hole portion penetrating in the axial direction,

the communication hole is formed obliquely with respect to the rotation axis,

the opening is located on the first bearing side, and the reservoir side opening is located on the second bearing side.

4. The driving device according to claim 2, wherein,

The partition wall portion has:

the communication hole is formed obliquely with respect to the rotation axis,

5. The driving device according to claim 3 or 4, wherein,

the opening portion includes a motor-side opening that opens at the motor housing portion.

6. The driving device according to claim 5, wherein,

the motor-side opening has an oil receiving portion having a diameter larger than that of the communication hole.

7. The driving device according to claim 3 or 4, wherein,

the opening portion includes a gear-side opening that opens at the gear housing portion.

8. The driving device according to claim 7, wherein,

the gear housing part is also provided with an oil receiving part which is arranged on the partition wall part and receives the oil,

the gear-side opening communicates with the oil receiving portion.

9. The driving device according to claim 8, wherein,

in a state where the rotation axis is arranged in the horizontal direction, the gear housing portion has:

an oil reservoir located in a lower region in the interior of the gear housing;

a storage portion located in an upper region in an interior of the gear housing portion; and

an oil supply hole formed in the storage portion and supplying the oil to the first bearing or the second bearing,

the oil supply hole is located above the oil receiving portion.

10. The driving device according to claim 1, wherein,

a plurality of the supply holes are provided along a circumferential direction of the spline shaft portion.

11. The driving device according to claim 1 or 10, wherein,

the spline shaft part has an annular supply path provided on the entire periphery of the outer peripheral surface,

the supply path is connected to the supply hole.

12. The driving device according to claim 11, wherein,

the supply path is an annular groove.

13. The driving device according to claim 11, wherein,

the supply hole and the supply path are provided in a portion of the hollow portion on an upstream side in a flow direction of oil in the hollow portion.

14. The driving device according to claim 12, wherein,