CN113098191A - Drive device - Google Patents

Abstract

One aspect of the driving device of the present invention includes: a motor having a rotor and a stator, the rotor having a motor shaft and a rotor body fixed to the motor shaft, the stator surrounding the rotor; a gear portion connected to the motor shaft; and a plurality of bearings rotatably supporting the motor shaft. The motor shaft has: a first shaft fixed to the rotor body; and a second shaft, one side of which is connected with the first shaft and the other side of which is connected with the gear part. One of the first shaft and the second shaft has a spline shaft portion having a plurality of external tooth portions on an outer peripheral surface. The other of the first shaft and the second shaft has a spline hole portion into which the spline shaft portion is fitted. The spline hole portion has a plurality of internal tooth portions on an inner peripheral surface thereof, which mesh with the plurality of external tooth portions. The gear portion has a helical gear portion connected to an outer peripheral surface of the second shaft. The drive has oil in the gap between the external toothing and the internal toothing.

Description

Drive device

Technical Field

The present invention relates to a drive device.

Background

There is known a drive device in which a rotor shaft of a motor and a drive shaft, to which power is transmitted through the rotor shaft, are connected to each other by spline coupling. For example, patent document 1 describes a drive device in which both end portions of a rotor shaft and both end portions of a drive shaft are supported by bearings, respectively.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-214646

In a drive device in which a rotor shaft and a drive shaft are connected by spline coupling, when a helical gear portion is connected to the drive shaft, an axial force is applied from the helical gear portion to the drive shaft. Therefore, when the direction of the torque applied to the bevel gear portion is reversed by switching the mode of the drive device or the like, the drive shaft moves in the axial direction. Here, in the spline coupling, relative movement of the rotor shaft and the drive shaft in the axial direction is basically allowed, and therefore, even if the drive shaft moves in the axial direction, the force in the axial direction is not easily transmitted to the rotor shaft. However, in a state where the spline-coupled external tooth portions and internal tooth portions are strongly engaged with each other, for example, axial end portions of the external tooth portions are engaged with the inner circumferential surface of the spline hole portion, and thus an axial force applied to the drive shaft may be transmitted to the rotor shaft. Therefore, the rotor shaft may move in the axial direction along with the axial movement of the drive shaft. When the shafts are moved in the axial direction as described above, a load in the axial direction may be applied to the bearings that support the shafts to be rotatable.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a drive device having a structure capable of suppressing an axial load applied to a bearing.

One aspect of the driving device of the present invention includes:

a motor having a rotor and a stator, the rotor having a motor shaft that rotates about a rotation axis and a rotor main body fixed to the motor shaft, the stator surrounding the rotor;

a gear part connected with the motor shaft; and

a plurality of bearings rotatably supporting the motor shaft. The motor shaft has:

a first shaft fixed to the rotor body; and

and a second shaft having one side connected to the first shaft and the other side connected to the gear portion. One of the first shaft and the second shaft has a spline shaft portion having a plurality of external tooth portions on an outer peripheral surface. The other of the first shaft and the second shaft has a spline hole portion into which the spline shaft portion is fitted. The spline hole portion has a plurality of internal tooth portions on an inner peripheral surface thereof, and the plurality of internal tooth portions and the plurality of external tooth portions are meshed with each other. The gear portion has a bevel gear portion connected to an outer peripheral surface of the second shaft. The drive device has oil at a gap between the outer teeth and the inner teeth.

According to one aspect of the present invention, the load in the axial direction applied to the bearing in the driving device can be suppressed.

Drawings

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

Fig. 2 is a sectional view showing a part of the motor shaft of the first embodiment.

Fig. 3 is a perspective view showing a part of the first shaft of the first embodiment.

Fig. 4 is a perspective view showing a part of the second shaft and a part of the gear portion in the first embodiment.

Fig. 5 is a cross-sectional view showing the meshing of the external teeth portion and the internal teeth portion of the first embodiment.

Fig. 6 is a perspective view showing a part of the second shaft and a part of the gear portion in the modification of the first embodiment.

Fig. 7 is a sectional view showing a part of a motor shaft according to a second embodiment.

Fig. 8 is a sectional view showing the meshing of the external teeth portion and the internal teeth portion in the second embodiment.

(symbol description)

1a driving device;

2, a motor;

3a gear portion;

6, a shell;

20 a rotor;

21. 221a motor shaft;

21a, 221a first axis;

21b, 121b, 221b second axis;

21c, 21d oil passage portions;

22 an expanding part;

23a through holes;

24 a rotor body;

26. 126, 226 spline shaft portions;

26a external teeth;

26b, 126b supply holes;

26c, 126c supply paths;

26d, 126d, 226 d;

27a bearing;

27a first bearing;

27b a second bearing;

28. 228 a spline hole portion;

28a inner teeth portion;

29. 70, 229 gap;

30 a stator;

41 a first bevel gear portion (bevel gear portion);

61 a motor housing section;

62 a gear housing section;

63 a partition wall portion;

66a first holding portion;

66b a second holding portion;

66c a storage section;

j1 rotating shaft;

and (4) O oil.

Detailed Description

In the following description, the vertical direction is defined with reference to the positional relationship when the drive device 1 of the present embodiment shown in each drawing is mounted on a vehicle on a horizontal road surface. In addition, in the drawings, an XYZ coordinate system is appropriately expressed 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 vertical upper side is simply referred to as "upper side", and the vertical lower side is simply referred to as "lower side". The X-axis direction is a direction orthogonal to the Z-axis direction, and is a front-rear direction of the vehicle on which the drive device 1 is mounted. In the following embodiments, the + X side is the front side of the vehicle and the-X side is the rear side of the vehicle. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction, and is a vehicle width direction, which is a lateral direction of the vehicle. In the following embodiments, the + Y side is the left side of the vehicle and the-Y side is the right side of the vehicle. The front-back direction and the left-right direction are horizontal directions orthogonal to the vertical direction.

The positional relationship in the front-rear direction is not limited to the positional relationship in the following embodiments, and the + X side may be the rear side of the vehicle and the-X side may be the front side of the vehicle. In this case, the + Y side is the right side of the vehicle and the-Y side is the left side of the vehicle.

The rotation shaft J1 shown in each figure as appropriate 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 "axial direction", a radial direction centering on the rotation axis J1 is simply referred to as "radial direction", and a circumferential direction centering on the rotation axis J1, that is, an axial direction of the rotation axis J1 is simply referred to as "circumferential direction". In the present specification, the "parallel direction" also includes a substantially parallel direction, and the "orthogonal direction" also includes a substantially orthogonal direction.

< first embodiment >

The drive device 1 of the present embodiment shown in fig. 1 is mounted on a vehicle having a motor as a power source, such as a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an Electric Vehicle (EV), and is used as the power source. The drive device 1 has a motor 2, a gear portion 3, a housing 6, an oil pump 96, a cooler 97, a duct 10, and a plurality of bearings 27, and the gear portion 3 includes 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 27 d. In the present embodiment, the drive device 1 does not include an inverter unit. In other words, the drive device 1 is configured to be separate from the inverter unit.

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 housed in the motor housing portion 61. The gear housing 62 houses the gear portion 3 therein. The gear housing 62 is located on the left side of the motor housing 61. The bottom portion 61f of the motor housing portion 61 is located above the bottom portion 62c of the gear housing portion 62. The partition wall 63 partitions the interior of the motor housing 61 and the interior of the gear housing 62 in the axial direction. The partition wall 63 is provided with a connection hole 68 that penetrates the partition wall 63 in the axial direction. The connection hole 68 connects the inside of the motor housing 61 and the inside of the gear housing 62. The partition wall 63 is located on the left side of the stator 30.

As shown in fig. 2, the partition wall 63 has a hole 66 that penetrates the partition wall 63 in the axial direction. The hole 66 is through which a motor shaft 21 described later is inserted. 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 66 c. That is, the partition wall portion 63 has a first holding portion 66a, a second holding portion 66b, and a reservoir portion 66 c. Further, the housing 6 has a first holding portion 66a, a second holding portion 66b, and a storage portion 66 c.

The first holding portion 66a is a portion that holds the first bearing 27a inside. The first holding portion 66a is open to the right. The first holding portion 66a opens inside the motor housing portion 61. The second holding portion 66b is a portion that holds the second bearing 27b therein. The second holding portion 66b is located on the left side of the first holding portion 66 a.

The second holding portion 66b is open to the right. The second holding portion 66b opens into the motor housing portion 62.

The inner diameter of the second holding portion 66b is larger than the inner diameter of the first holding portion 66a, for example.

The reservoir 66c is a portion where the oil supply O is stored around the second shaft 21b described later. The reservoir portion 66c is located between the first holding portion 66a and the second holding portion 66b in the axial direction. The inside of the reservoir 66c is open to both axial sides. The inside of the storage portion 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 storage portion 66 c. This enables the oil O in the reservoir 66c to 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 reservoir portion 66c has an inner diameter smaller than that of the first holding portion 66 a.

As shown in fig. 1, the casing 6 internally accommodates oil O as a refrigerant. In the present embodiment, oil O is stored in the motor storage portion 61 and the gear storage portion 62. An oil reservoir P in which the oil supply O is stored is provided in a lower region inside the gear housing portion 62. The oil O in the oil reservoir P is fed to the inside of the motor housing portion 61 through an oil passage 90 described later. The oil O delivered into the motor housing portion 61 is accumulated in a lower region inside the motor housing portion 61. At least a part of the oil O stored in the motor housing portion 61 moves to the gear housing portion 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" may be used as long as the oil is located in the certain portion during at least a part of the driving of the motor, and the oil may not be located in the certain portion when the motor is stopped. For example, in the present embodiment, the oil O may be contained in the motor housing portion 61 as long as the oil O is located in the motor housing portion 61 during at least a part of the driving of the motor 2, and all of the oil O in the motor housing portion 61 may be moved to the gear housing portion 62 through the connection hole 68 when the motor 2 is stopped. A part of the oil O fed into the motor housing portion 61 through the oil passage 90 described later may be left in 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 4 and the differential 5. Further, the oil O is used for cooling the motor 2. As the oil O, in order to exhibit functions of a lubricating oil and a cooling oil, it is preferable to use an oil equivalent to an Automatic Transmission lubricating oil (ATF) having a low viscosity.

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 drive device 1 and a function as a power generation device. In the following description, a state in which the motor 2 is used as a power source to drive the vehicle is referred to as a drive mode, and a state in which the motor 2 is used as a power generator to generate power is referred to as a regeneration mode. The motor 2 has a device 20 and a stator 30.

The motor 20 is rotatable about a rotation shaft J1 extending in the horizontal direction. The motor 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 fixed to the outer peripheral surface of the motor shaft 21 and a rotor magnet fixed to the rotor core. The torque of the rotor 20 is transmitted to the gear portion 3.

The motor shaft 21 extends in the axial direction around the rotation shaft J1. The motor shaft 21 rotates about a rotation shaft 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 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 21 b.

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

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 shaft 21 a. The first shaft 21a is housed inside the motor housing portion 61. Both axial end portions of the first shaft 21a are rotatably supported 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 for rotatably supporting both end portions in the axial direction of the first shaft 21 a. As shown in fig. 2, the end portion on the left side of the first shaft 21a is located inside the first holding portion 66 a. The left end surface of the first shaft 21a axially faces the inside of the storage portion 66 c.

As shown in fig. 3, the first shaft 21a has a spline hole portion 28. In the present embodiment, the spline hole 28 is recessed rightward from the left end of the first shaft 21 a. The spline hole portion 28 is, for example, a circular hole centered on the rotation shaft J1. The inside of the spline hole portion 28 is the inside at the end on the left side of the first shaft 21 a. The spline hole portion 28 extends in the axial direction. The spline hole portion 28 is open to both axial sides.

The spline hole 28 has a plurality of internal tooth portions 28a on the inner peripheral surface. The plurality of inner teeth 28a protrude radially inward. The plurality of internal teeth 28a extend in the axial direction. The plurality of inner teeth 28a are arranged at intervals in the circumferential direction. The plurality of inner teeth 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 circumferential surface of the spline 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 enlarged diameter portion 22 is larger than the inner diameter of portions of the first shaft 21a located on both sides in the axial direction of the enlarged diameter portion 22. The enlarged diameter portion 22 is located on the right side of the spline hole portion 28. The inside of the enlarged diameter portion 22 is connected to the inside of the spline hole portion 28. The inner peripheral surface 22a of the enlarged diameter portion 22 has a tapered surface 22b and a cylindrical surface 22 c.

The tapered surface 22b is a left 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 spline hole 28. The tapered surface 22b is centered on the pivot J1. The inner diameter of the tapered surface 22b becomes larger 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 portion of the inner peripheral surface 22 a. The cylindrical surface 22c is centered on the rotation axis J1.

As shown in fig. 1, the first shaft 21a has a through hole 23 that penetrates from the inner peripheral surface to the outer peripheral surface of the first 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-holes 23 include through-holes 23a that pass through from the inner peripheral surface to the outer peripheral surface of the enlarged diameter portion 22. The plurality of through holes 23a are provided along the circumferential direction. For example, two through holes 23a are provided.

A part of the oil O passing through the oil passage portion 21c of the first shaft 21a flows out from the through hole 23a to the outside of the first shaft 21 a. The oil O flowing out of the through hole 23a is discharged to the outside in the radial direction 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 shaft 21b is located on the left side of the first shaft 21 a. The second shaft 21b is a shaft having one side connected to the first shaft 21a and the other side connected to the gear portion 3. In the present specification, the phrase "one side of the second shaft is connected to the first shaft and the other side is connected to the gear portion" may be used as long as the portion of the second shaft connected to the gear portion is located at a position axially farther from the first shaft than the portion of the second shaft connected to the first shaft. That is, in the present embodiment, the phrase "one side of the second shaft 21b is connected to the first shaft 21a and the other side is connected to the gear portion 3" may be used as long as the portion of the second shaft 21b connected to the gear portion 3 is located on the left side of the portion of the second shaft 21b connected to the first 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 shaft 21b is connected to the gear portion 3.

The second shaft 21b is housed inside the gear housing portion 62. Both axial end portions of the second shaft 21b are rotatably supported 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 for rotatably supporting both end portions in the axial direction of the second shaft 21 b. As shown in fig. 2, the right end of the second shaft 21b protrudes into the motor housing 61 through the hole 66.

As shown in fig. 4, the second shaft 21b has a spline shaft portion 26. In the present embodiment, the spline shaft 26 is the right end of the second shaft 21 b. The splined shaft portion 26 extends in the axial direction. As shown in fig. 2, in the present embodiment, the second shaft 21b is a hollow shaft, and therefore, the spline 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 inside the first shaft 21 a. The clearance 29 between the outer peripheral surface of the spline shaft 26 and the inner peripheral surface of the spline hole 28 opens inside the storage portion 66 c.

As shown in fig. 4, the spline shaft portion 26 has a plurality of external tooth portions 26a on the outer peripheral surface. The plurality of external teeth portions 26a protrude radially outward. The plurality of outer teeth 26a extend in the axial direction. The plurality of outer teeth 26a are arranged at intervals in the circumferential direction. The plurality of outer teeth 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 teeth 26a is the same as that of the internal teeth 28 a.

As shown in fig. 5, the plurality of inner teeth 28a intermesh with the plurality of outer teeth 26 a. Thus, in the drive mode, rotation of the first shaft 21a about the rotation shaft J1 is transmitted to the second shaft 21b via the plurality of inner teeth 28a and the plurality of outer teeth 26 a. Further, in the regeneration mode, the rotation of the second shaft 21b about the rotation shaft J1 is transmitted to the first shaft 21a via the plurality of inner teeth 28a and the plurality of outer teeth 26 a.

The interval between the outer teeth 26a adjacent in the circumferential direction is larger than the size of the inner teeth 28a in the circumferential direction. The circumferentially adjacent inner teeth 28a are spaced apart from each other by a larger dimension than the outer teeth 26a in the circumferential direction. Therefore, a gap 70 is provided between the external teeth 26a and the internal teeth 28 a. The gap 70 is provided in plurality at intervals in the circumferential direction. As shown in fig. 2, the gap 70 between the external teeth 26a and the internal teeth 28a in the circumferential direction extends in the axial direction. The clearance 70 is a part of the clearance 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 to both axial sides. The gap 70 has an opening 70a that opens inside the first shaft 21 a. The opening 70a is an end portion on the right side of the gap 70. In the present embodiment, the opening 70a opens inside the enlarged diameter portion 22.

The clearance 70 has an opening 70b that opens inside the spline hole 28. The opening 70b is an end portion on the left side of the gap 70. The opening 70b opens into the spline hole 28 at a portion on the left side of the internal teeth 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 enlarged diameter portion 22 and the inside of the storage portion 66c are connected via the gap 70.

The spline shaft 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, the 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 radially sandwich the rotation shaft J1. As shown in fig. 4, 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 of the spline shaft portion 26. The radially outer end of the supply hole 26b is formed by cutting out 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 outer tooth portion 26a and the inner tooth portion 28a in the gap 29.

The radially outer end of the supply hole 26b may be provided in a portion of the outer peripheral surface of the spline shaft 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 is, for example, a portion of the outer peripheral surface of the spline shaft portion 26 located between the external tooth portions 26a adjacent to each other in the circumferential direction. In this case, the external teeth portion 26a is not cut off by the supply hole 26 b.

As shown in fig. 4, the spline shaft 26 has an annular supply passage 26 c. The supply passage 26c is provided over the entire outer peripheral surface of the spline shaft 26. The supply passage 26c is annular and centered on the rotation axis J1, for example. 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 circumferentially adjacent external teeth 26a of the spline shaft 26. The supply passage 26c is located at the axial center portion of the outer peripheral surface of the spline shaft portion 26.

The supply passage 26c penetrates all of the plurality of outer teeth portions 26a in the circumferential direction. All the external teeth portions 26a are axially divided by the supply passage 26 c. The circumferentially adjacent external teeth 26a are connected to each other via a supply passage 26 c. A radially outer end of the supply hole 26b is provided in the middle of the supply passage 26 c. Thereby, the supply passage 26c is connected to the supply hole 26 b. In the present embodiment, the axial width of the supply passage 26c 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 outward of the rotor 20. The stator 30 surrounds the rotor 20. The stator 30 has a stator core 32 and a coil assembly 33. Stator core 32 is fixed to the inner circumferential surface of motor housing 61. Although not shown, the stator core 32 has: a cylindrical core back portion 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 entire circumference in the circumferential direction.

The coil assembly 33 has a plurality of coils 31 mounted to the stator core 32 along the circumferential direction. The plurality of coils 31 are attached to the respective pole teeth of the stator core 32 via insulators 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 along the circumferential direction over the entire circumference. 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 projecting in the axial direction from the stator core 32. The coil end 33a is a portion protruding from the stator core 32 toward the right side. The coil end 33b is a portion protruding toward the left side from the stator core 32. The coil end 33a includes a portion of each coil 31 included in the coil assembly 33 that protrudes to the right of the stator core 32. The coil end 33b includes a portion of each coil 31 included in the coil assembly 33 that protrudes to the left side of the stator core 32. The coil ends 33a and 33b are, for example, annular around the rotation axis J1. 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 shaft 21a so as to be rotatable. The second bearing 27b and the fourth bearing 27d are bearings for rotatably supporting the second shaft 21 b. 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 61, and the cover member 61b covers the right side of the rotor 20 and the stator 30. The fourth bearing 27d is held by a 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 positioned radially outward of the inner ring, and a plurality of balls positioned 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 the fixed-position preload manner is fixed in a state where the outer ring is displaced in the axial direction with respect to the inner ring in accordance with a dimension measured in advance. This can suppress the outer ring from wobbling relative to the inner ring, and can improve the accuracy of the rotational 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 becomes 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, when the fixed-position preload is applied to the ball bearing, the inner ring and the outer ring are assembled in a state where a slight gap is provided in the relationship of the inner ring, the balls, and the outer ring. In the assembled ball bearing, the outer ring is movable relative to the inner ring in the axial direction by the gap. In the present specification, the above 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 clearance.

Therefore, the motor shaft 21 supported by the bearings 27 of the present embodiment can move in the axial direction by the remaining gap of the bearings 27. More specifically, the first shaft 21a can move the first bearing 27a and the third bearing 27c in the axial direction by the amount of the remaining clearance. The second shaft 21b is able to move the second bearing 27b and the fourth bearing 27d in the axial direction by the amount of remaining clearance.

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 device 5 via the reduction gear device 4.

The reduction gear 4 is connected to the motor 2. The reduction gear 4 reduces the rotation 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 device 5. The reduction gear 4 has a first bevel gear portion 41, a second bevel gear portion 42, a third bevel gear portion 43, and an intermediate shaft 45. That is, the gear portion 3 has a first bevel gear portion 41, a second bevel gear portion 42, a third bevel gear portion 43, and an intermediate shaft 45.

The first bevel gear portion 41 is connected to the outer peripheral surface of the second shaft 21 b. As shown in fig. 4, the first bevel gear portion 41 is integrally molded with the second shaft 21b, for example. The first bevel gear portion 41 may be formed separately from the second shaft 21b and fixed to the outer peripheral surface of the second shaft 21 b. The first bevel gear portion 41 rotates about the rotation shaft J1 together with the motor shaft 21.

As shown in fig. 1, the intermediate shaft 45 extends along the intermediate shaft J2 parallel to the rotation shaft J1. The intermediate shaft 45 rotates about the intermediate shaft J2. The second bevel gear portion 42 and the third bevel gear portion 43 are fixed to the outer peripheral surface of the intermediate shaft 45. The second bevel gear portion 42 and the third bevel gear portion 43 are connected via an intermediate shaft 45. The second bevel gear portion 42 and the third bevel gear portion 43 rotate about the intermediate shaft J2. The second bevel gear portion 42 meshes with the first bevel 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 shaft 21, the first bevel gear portion 41, the second bevel gear portion 42, the intermediate shaft 45, and the third bevel 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 a required reduction ratio. In the present embodiment, the reduction gear 4 is a parallel axis gear type reduction gear in which the axes of the gears are arranged in parallel.

The differential device 5 is connected to the motor 2 via the reduction gear 4. The differential device 5 is a device for transmitting the torque output from the motor 2 to the wheels of the vehicle. The differential device 5 absorbs a 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. In this way, 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 includes a ring gear 51, a gear housing, a pair of pinion gears, a pinion shaft, and a pair of side gears. The ring gear 51 rotates about a differential shaft J3 parallel to the rotation shaft 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 supply O circulates inside the casing 6. The oil passage 90 is a path of the oil O that supplies the oil O from the oil reservoir P to the motor 2 and leads the oil O to the oil reservoir P again. The oil passage 90 is provided so as to extend between the inside of the motor housing 61 and the inside of the gear housing 62.

In addition, 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 directed in one direction, but also a path that temporarily retains oil and a path through which oil drops. The path for temporarily retaining oil includes, for example, a reservoir portion for storing 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 are configured such that the oil supply O circulates inside the casing 6. 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 91 d. 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 lift path 91a is a path through which the oil O is lifted from the oil reservoir P by the rotation of the ring gear 51 of the differential device 5 and received by the first reservoir 93. The first storage portion 93 opens to the upper side. The first reservoir 93 receives the oil O lifted by the ring gear 51. Further, when the liquid level S of the oil reservoir P is high immediately after the motor 2 is driven, the first reservoir portion 93 receives the oil O lifted by the second bevel gear portion 42 and the third bevel gear portion 43 in addition to the oil O lifted by the ring gear 51.

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 supply O passes inside the motor shaft 21. The in-shaft 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 through 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 through hole 23 of the motor shaft 21 and penetrates the interior of the rotor body 24 to be scattered to the stator 30.

In the in-shaft path 91c, a centrifugal force is applied to the oil O inside the rotor 20 as the rotor 20 rotates. Thereby, the oil O continuously scatters radially outward from the rotor 20. The path inside the rotor 20 becomes negative pressure with the scattering of the oil O, and the oil O stored in the first reservoir 93 is sucked into the rotor 20, thereby filling the path inside the rotor 20 with the oil O.

The oil O reaching the stator 30 deprives heat from the stator 30. The oil O having cooled the stator 30 drops downward and is accumulated in the lower region of the motor housing portion 61. The oil O accumulated in the lower region of the motor housing portion 61 moves to the gear housing portion 62 through the connection hole 68 provided in the partition wall portion 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 shaft inner path 91c is supplied to the gap 70 between the external teeth portion 26a and the internal teeth portion 28a via the supply hole 26 b. Thus, as shown in fig. 5, the drive device 1 has oil O in the gap 70 between the external teeth 26a and the internal teeth 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 reservoir 66 c.

In the present specification, the phrase "the drive device has oil in the gap between the outer teeth and the inner teeth" may be used as long as the oil is located in the gap between the outer teeth and the inner teeth in at least a part of the driving process of the motor, and the oil may not be located in the gap between the outer teeth and the inner teeth when the motor is stopped. In the present specification, the phrase "the drive device has oil in the gaps between the outer teeth and the inner teeth" is used as long as oil is present in at least one of the gaps between the outer teeth and the inner teeth. That is, in the present embodiment, the oil O may not be present in some of the plurality of gaps 70 among the 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. Second oil passage 92 is provided with an oil pump 96, a cooler 97, and a pipe 10. The second oil passage 92 has a first flow passage 92a, a second flow passage 92b, a third flow passage 92c, and a fourth flow passage 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 to the oil pump 96. The second flow path 92b connects the oil pump 96 and the cooler 97. The third flow path 92c connects the cooler 97 to 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 to the inside of the duct 10. The pipe 10 extends in the axial direction. The duct 10 is located radially outside the stator 30. The duct 10 has: oil supply holes that supply oil to the coil ends 33a, 33 b; and an oil supply hole that supplies oil to the stator core 32. Although not shown, for example, a plurality of pipes 10 are provided.

The oil pump 96 is a pump that conveys oil O as refrigerant. In the present embodiment, the oil pump 96 is an electrically driven pump. 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 duct 10. The oil O flowing into the pipe 10 flows to the right side in the pipe 10 and is supplied to the stator 30 from an oil supply port 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 portion 61. The oil O accumulated in the lower region of the motor housing portion 61 moves to the oil reservoir P of the gear housing portion 62 through the connection hole 68 provided in the partition wall portion 63. As described above, the second oil passage 92 supplies the oil O to the stator 30.

Cooler 97 cools oil O passing through second oil passage 92. 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 cooler 97 and the cooling water passing through the cooling water pipe 98 are cooled by heat exchange.

When the drive device 1 is in the drive 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 regeneration mode, the rotation of the second shaft 21b is transmitted to the first shaft 21 a. When the mode of the motor 2 is switched, the circumferential surfaces of the outer teeth 26a and the inner teeth 28a are switched.

Specifically, for example, as shown in fig. 5, when the drive device 1 is in the drive mode, one circumferential surface of the internal tooth portion 28a is in contact with the other circumferential surface of the external tooth portion 26 a. Here, the circumferential side is a side toward which an arrow θ faces. The other side in the circumferential direction is opposite 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 shaft rotates.

In this case, when the drive device 1 is switched from the drive mode to the regeneration mode, the outer teeth 26a are relatively moved with respect to the inner teeth 28a in one circumferential direction as indicated by the hollow arrows in fig. 5. In the regeneration mode, the first shaft 21a is rotated by the rotation of the second shaft 21b in a state where one circumferential surface of the outer teeth 26a is in contact with the other circumferential surface of the inner teeth 28 a. Thereby, the motor 2 functions as an engine.

When the drive device 1 is switched from the regeneration mode to the drive mode, the first shaft 21a is rotated by the motor 2, and therefore, the first shaft 21a is rotated relative to the second shaft 21b toward the circumferential side. As a result, the internal teeth portions 28a move relative to the external teeth portions 26a in the circumferential one-side direction, and the external teeth portions 26a and the internal teeth portions 28a come into contact with each other in the state shown in fig. 5. Therefore, the rotation of the first shaft 21a is transmitted to the second shaft 21 b.

When the drive device 1 is in the drive 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 wheel. Therefore, a torque in the opposite direction to the direction in which the first shaft 21a rotates is applied at the second shaft 21b and the gear portion 3. Thus, when the mode of the drive device 1 is switched between the drive mode and the regeneration mode, the direction of the torque applied to the second shaft 21b is reversed.

In the present embodiment, the gear portion 3 includes the first bevel gear portion 41 connected to the outer peripheral surface of the second shaft 21 b. Therefore, at the second shaft 21b, stress of one side or the other side in the axial direction is applied depending on the application direction of the torque. Thus, when the mode of the drive device 1 is switched and the direction in which torque is applied is reversed, the second shaft 21b moves in the axial direction by the remaining clearance between the second bearing 27b and the fourth bearing 27 d. Therefore, an axial load may be applied to the bearing 27 supporting the second shaft 21b due to the axial movement of the second shaft 21 b.

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

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

When the second shaft 21b moves in the axial direction toward the first shaft 21a, the axial end of the external teeth 26a is easily engaged with the inner circumferential surface of the spline hole 28, and the axial movement of the second shaft 21b is easily transmitted to the first shaft 21 a. On the other hand, when the second shaft 21b moves in a direction away from the first shaft 21a, the axial end of the external teeth 26a is less likely to be engaged with the inner circumferential surface of the spline hole 28, and the axial movement of the second shaft 21b is less likely to be transmitted to the first shaft 21 a. That is, when the second shaft 21b moves in the axial direction toward the first shaft 21a, the possibility that the load in the axial direction is applied to the bearing 27 that supports the first shaft 21a is likely to increase.

Further, the present inventors have newly found that there is a possibility that the first shaft 21a moves in the axial direction along with the axial movement of the second shaft 21b, and particularly, when the second shaft 21b moves in the axial direction in a direction approaching the first shaft 21a, there is a high possibility that the first shaft 21a also moves in the axial direction.

In view of the above problem, according to the present embodiment, the drive device 1 has the oil O in the gap 70 between the external teeth portions 26a and the internal teeth portions 28 a. Therefore, the oil O functions as a damper, and the relative speed at which the outer teeth portions 26a and the inner teeth portions 28a approach 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 circumferential one surface of the external teeth 26a approaches the circumferential other surface of the internal teeth 28a as indicated by the hollow arrow in fig. 5, the oil O exists in the gap 70, and therefore the external teeth 26a and the internal teeth 28a approach each other relatively slowly while pushing the oil O out of the gap 70.

This can extend the time until the external teeth 26a and the internal teeth 28a come into meshing contact with each other in the opposite direction at the time of mode switching. Therefore, the second shaft 21b can be moved relative to the first shaft 21a in the axial direction until the external teeth 26a and the internal teeth 28a strongly mesh with each other. Therefore, at the time of mode switching, the force in the axial direction can be suppressed from being applied to the first shaft 21a from the second shaft 21b, so that the first shaft 21a can be suppressed from moving in the axial direction. Therefore, the axial load applied to the first bearing 27a and the third bearing 27c that support the first shaft 21a can be suppressed. Particularly, the generation of a sudden load at the first bearing 27a and the third bearing 27c can be suppressed. Thereby, bearings that are small and resistant to a small load can be used as the first bearing 27a and the third bearing 27 c.

Further, when the second shaft 21b moves in the axial direction, the oil O can also function as a lubricating oil so that the second shaft 21b can easily slide in the axial direction. The oil O also functions as a damper by the viscosity of the oil O with respect to the axial movement of the second shaft 21 b. Therefore, the speed at which the second shaft 21b moves in the axial direction can also be reduced. This can suppress the axial load applied to the second bearing 27b and the fourth bearing 27d that support the second shaft 21b when the second shaft 21b moves in the axial direction. Particularly, the generation of a sudden load at the second bearing 27b and the fourth bearing 27d can be suppressed. Therefore, bearings that are small and resistant to small loads can be used as the second bearing 27b and the fourth bearing 27 d.

Thus, 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 include the bearing 27 that rotatably supports both axial end portions of the first shaft 21a and the bearing that rotatably supports both axial end portions of the second shaft 21 b.

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

Even when the axial movement of the second shaft 21b is transmitted to the first shaft 21a after the outer teeth 26a and the inner teeth 28a come into contact with each other, the oil O can function as a damper for the axial movement of the first shaft 21a due to the viscosity of the oil O. Therefore, the speed at which the first shaft 21a moves in the axial direction can also be reduced. Thereby, even when the first 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 shaft 21a can be suppressed. Particularly, the generation of a sudden load at the first bearing 27a and the third bearing 27c can be suppressed.

On the other hand, during the mode switching of the drive device 1 until the external teeth 26a and the internal teeth 28a come into meshing contact with each other in the opposite direction, the movement of the first shaft 21a in the axial direction can be more desirably suppressed when the axial movement of the second shaft 21b is performed as a whole. Therefore, the axial load applied to the bearing 27 supporting the first shaft 21a can be more desirably suppressed. Particularly, it is possible to more desirably suppress the occurrence of a sudden load at the bearing 27 that supports the first shaft 21 a.

In addition, the external teeth portions 26a and the internal teeth portions 28a do not directly contact before the external teeth portions 26a and the internal teeth portions 28a are brought into meshing contact in reverse after the mode switching of the drive device 1. However, even in this case, the transmission of the rotation between the first shaft 21a and the second shaft 21b can be performed through the oil O in the gap 70. Therefore, even when the drive device 1 is switched from the regenerative mode to the drive mode, for example, the rotational torque of the first shaft 21a is transmitted to the second shaft 21b before the external teeth portions 26a come into meshing contact with the internal teeth portions 28a in the reverse direction. Thus, before the external teeth portions 26a come into meshing contact with the internal teeth portions 28a in the opposite direction, the torque applied to the second shaft 21b is reversed, and the second 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 that supports the first shaft 21a can be suppressed. In particular, it is possible to suppress the occurrence of a sudden load on the bearing 27 that supports the first shaft 21 a.

Further, according to the present embodiment, the spline shaft portion 26 has the hollow portion 26d and the 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 teeth 26a and the internal teeth 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 26 b. This makes it easy to maintain the state in which the oil O is present in the gap 70 between the external teeth 26a and the internal teeth 28 a. The oil O can also be supplied through the supply hole 26b to the gap 70 newly generated by bringing the external teeth 26a into meshing contact with the internal teeth 28a in the opposite direction in 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, a gap 70 generated between the other circumferential surface of the outer tooth portion 26a and the one circumferential surface of the inner tooth portion 28a when the outer tooth portion 26a is moved relatively to the inner tooth portion 28a from the state shown in fig. 5 toward the one circumferential side.

Further, according to the present embodiment, the supply hole 26b is provided in plurality along the circumferential direction of the spline shaft portion 26. Therefore, the oil O can be supplied more desirably and easily to each gap 70 between the external tooth portions 26a and the internal tooth portions 28a via the supply hole 26 b.

Further, according to the present embodiment, the spline shaft portion 26 has an annular supply passage 26c provided over the entire circumference of the outer circumferential 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 portion 26 can be easily supplied to the entire periphery of the spline shaft portion 26 via the supply passage 26 c. Thereby, the oil O can be easily supplied to all of the plurality of gaps 70. Therefore, the damping function of the oil O can be obtained more desirably. 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 further suppressed.

Further, according to the present embodiment, the supply passage 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 caused to flow over the entire periphery while being retained in the supply passage 26 c. Thereby, the oil O can be easily and uniformly supplied to all of the plurality of gaps 70.

Further, according to the present embodiment, the inside of the enlarged diameter portion 22 and the inside of the storage portion 66c are connected via the gaps 70 between the external teeth 26a and the internal teeth 28 a. Therefore, the enlarged diameter portion 22 and the reservoir portion 66c, which easily accumulate a large amount of oil O, 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 further suppressed.

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

(modification example)

As shown in fig. 6, in the second shaft 121b of the present modification, the entire spline shaft portion 126 in the axial direction is constituted by the hollow portion 126d as in the above-described embodiment. As in the above 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 the present modification, the supply hole 126b and the supply passage 126c are provided in a portion on the left side of the hollow portion 126 d. That is, the supply hole 126b and the supply passage 126c are provided in the 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 through the supply hole 126b and the supply passage 126c is easily made to flow in the same direction as the oil O flows in the hollow portion 126d in the gap 70, and the oil can be easily supplied to the entire axial direction of the gap 70. This makes it possible to desirably supply the oil O to the entire gap 70.

In the present specification, the phrase "the supply hole and the supply passage are provided in the hollow portion at a portion on the upstream side in the flow direction of the oil in the hollow portion" may be any as long as the supply hole and the supply passage are located on the upstream side of the center of the hollow portion in the flow direction of the oil in the hollow portion. In the present modification, the supply hole 126b and the supply passage 126c are located on the left side of 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 passage 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 passage 126 c. The other structure of the second shaft 121b is the same as that of the second shaft 21b described above.

< second embodiment >

As shown in fig. 7, in the second shaft 221b of the motor shaft 221 of the present embodiment, the entire axial direction of the spline shaft portion 226 is constituted by the hollow portion 226d as in the above-described embodiment. Unlike the first embodiment, in the present embodiment, the spline shaft portion 226 does not have the supply hole 26b and the supply passage 26 c. A gap 229 between the outer peripheral surface of the spline shaft portion 226 and the inner peripheral surface of the spline hole portion 228 opens inside the first shaft 221 a. In the present embodiment, the oil O flows into the gap 229 from inside the first shaft 221 a. Thereby, the oil O flows into the gaps 70 between the external teeth portions 26a and the internal teeth portions 28 a. Therefore, the supply hole 26b and the supply passage 26c do not need to be provided in the second shaft 221b, and the second shaft 221b can be easily manufactured.

As shown in fig. 8, in the present embodiment, the number of teeth of the internal tooth portion 28a of the spline hole 228 is smaller than the number of teeth of the external tooth portion 26a of the spline shaft 226. Therefore, the area of the gap 229 between the inner peripheral surface of the spline hole 228 and the outer peripheral surface of the spline shaft 226, which is open in the first shaft 221a, can be increased by the number of internal teeth 28 a. This allows the oil O to easily flow from within the first shaft 221a into the gap 229. Therefore, the oil O can be easily supplied to the gap 70 which is a part of the gap 229.

In the present embodiment, the number of teeth of the internal teeth portion 28a is half of the number of teeth of the external teeth portion 26 a. Therefore, the two outer teeth portions 26a are located between the circumferentially adjacent inner teeth portions 28 a. This can increase the opening area of the gap 229 by the gap between the outer teeth 26a adjacent to each other in the circumferential direction. The other structure of the motor shaft 221 is the same as that of the motor shaft 21 of the first embodiment.

The present invention is not limited to the above-described embodiments, and other configurations can be adopted within the scope of the technical idea of the present invention. A method of supplying oil to the gap between the outer teeth portion and the inner teeth portion is not particularly limited. The number of supply holes provided in the spline shaft portion is not particularly limited. The annular supply passage provided in the spline shaft portion may not be a groove. The supply passage may be formed by an outer peripheral surface of a portion of the spline shaft portion located between the circumferentially adjacent external teeth portions and a hole penetrating each external tooth portion in the circumferential direction. The drive device may not have a structure for actively supplying oil to the gap between the external teeth portion and the internal teeth portion as long as the drive device has oil in the gap between the external teeth portion and the internal teeth portion.

The spline shaft portion may be formed with a hollow portion only in a part in the axial direction. The spline shaft portion may not have a hollow portion. In this case, the entire spline shaft portion in the axial direction is a solid portion. 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 toothing can be less than the number of teeth of the internal toothing. The first and second shafts may also be solid shafts.

The bearing that supports the motor shaft to be rotatable may not include either a bearing that supports the first shaft or a bearing that supports the second shaft. The first shaft may not be supported by bearings at both axial ends. The second shaft may not be supported by bearings at both axial ends.

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

Claims (13)

1. A drive device, comprising:

a motor having a rotor and a stator, the rotor having a motor shaft that rotates about a rotation axis and a rotor main body fixed to the motor shaft, the stator surrounding the rotor;

a gear part connected with the motor shaft; and

a plurality of bearings rotatably supporting the motor shaft,

the motor shaft has:

a first shaft fixed to the rotor body; and

a second shaft having one side connected to the first shaft and the other side connected to the gear part,

one of the first shaft and the second shaft has a spline shaft portion having a plurality of external tooth portions on an outer peripheral surface,

the other of the first shaft and the second shaft has a spline hole portion into which the spline shaft portion is fitted,

the spline hole portion has a plurality of internal tooth portions on an inner peripheral surface thereof, the plurality of internal tooth portions and the plurality of external tooth portions are meshed with each other,

the gear portion has a bevel gear portion connected to an outer peripheral surface of the second shaft,

oil is present at the gap between the outer teeth and the inner teeth.

2. The drive of claim 1,

the spline shaft portion has:

a hollow portion extending in an axial direction; 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 gap between the outer teeth and the inner teeth.

3. The drive of claim 2,

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

4. The drive device according to claim 2 or 3,

the spline shaft portion has an annular supply passage provided over the entire circumference of the outer peripheral surface,

the supply passage is connected to the supply hole.

5. The drive of claim 4,

the supply path is an annular groove.

6. The drive device according to claim 4 or 5,

the oil passes through the inside of the hollow portion,

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

7. The drive device according to any one of claims 1 to 6,

the first shaft and the second shaft are hollow shafts connected to each other inside and have an oil passage portion inside,

a gap between an outer peripheral surface of the spline shaft portion and an inner peripheral surface of the spline hole portion is opened in the other shaft.

8. The drive of claim 7,

the number of teeth of the inner tooth portion is less than that of the outer tooth portion.

9. The drive device according to claim 7 or 8,

the drive device further has a housing that houses the motor and the gear portion inside,

the other shaft has an enlarged diameter portion with an enlarged inner diameter,

the housing has a reservoir portion that supplies oil to be stored around the one shaft,

the inside of the diameter-expanding portion and the inside of the storage portion are connected via a gap between the outer tooth portion and the inner tooth portion.

10. The drive of claim 9,

the housing has:

a motor housing portion that houses the motor therein;

a gear housing portion that houses the gear portion therein; and

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

the bearing includes:

a first bearing that supports the first shaft to be rotatable; and

a second bearing that supports the second shaft to be rotatable,

the partition wall portion has:

the reservoir section;

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

a second holding portion that holds the second bearing inside,

the interior of the first holding portion and the interior of the second holding portion are connected via the interior of the reservoir portion.

11. The drive device as claimed in claim 9 or 10,

the other shaft has a through hole penetrating from an inner peripheral surface to an outer peripheral surface of the enlarged diameter portion.

12. The drive device according to any one of claims 1 to 11,

said one axis is said second axis and said one axis is said second axis,

the other shaft is the first shaft.

13. The drive device according to any one of claims 1 to 12,

a plurality of said bearings comprising:

a bearing that supports both axial end portions of the first shaft so as to be rotatable; and

and bearings for rotatably supporting both axial end portions of the second shaft.

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