Drive unit

Abstract

To provide a drive unit having a configuration capable of improving efficiency for supplying fluid to each part.SOLUTION: A drive unit 100 comprises: a motor 20 having a rotor 21, and a stator 22 facing the rotor 21 with a gap therebetween; a gear mechanism 30 connected with the rotor 21; a housing 10 having a motor housing 11 for housing the motor 20 inside, and a gear housing 12 for housing the gear mechanism 30 inside; and a flow channel 90 in which fluid flows. The rotor 21 comprises a hollow motor shaft 23 extending in an axial direction. The gear mechanism 30 comprises a hollow gear shaft 33. The flow channel 90 includes: a first flow channel part 91 connecting the inside of the gear housing 12 with the inside of the gear shaft 33; a second flow channel part 92 connected with the first flow channel part 91; a third flow channel part 93 connected with a part on the other side in the axial direction of the second flow channel part 92; and a first fluid supply part 94 connected with the third flow channel part 93 and located on an upper side in a vertical direction of the stator 22.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a drive device.

Background Art

[0002] There is known a drive device including a supply oil passage that supplies oil. For example, Patent Document 1 describes, as such a drive device, a drive device mounted on an electric vehicle.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the above-described drive device, there may be cases where a plurality of supply oil passages for supplying oil to respective parts are provided, such as a supply oil passage for supplying oil to a stator and a supply oil passage for supplying oil into a hollow shaft. In such a case, there has been a demand for being able to supply oil more efficiently to respective parts.

[0005] In view of the above circumstances, an object of the present invention is to provide a drive device having a structure capable of improving the efficiency of supplying fluid to respective parts.

Means for Solving the Problem

[0006] One aspect of the drive device of the present invention comprises a motor having a rotor rotatable about a central axis and a stator facing the rotor with a gap between them, a gear mechanism connected to the rotor, a motor housing housing the motor, a housing located on one axial side of the motor housing and having a gear housing housing the gear mechanism, and a fluid passage through which fluid flows. The rotor has a hollow motor shaft extending in the axial direction. The gear mechanism has a hollow gear shaft connected to one axial side of the motor shaft. The gear housing houses the fluid. The fluid passage has a first fluid passage section connecting the inside of the gear housing and the inside of the gear shaft, a second fluid passage section connected to the first fluid passage section, at least a portion of which is composed of the inside of the gear shaft and the inside of the motor shaft, a third fluid passage section connected to the other axial side of the second fluid passage section, and a first fluid supply section connected to the third fluid passage section and located vertically above the stator.

[0007] One aspect of the drive device of the present invention comprises a motor having a rotor rotatable about a central axis and a stator facing the rotor with a gap between them, a gear mechanism connected to the rotor, a motor housing housing the motor, a housing located on one axial side of the motor housing and having a gear housing housing the gear mechanism, a hollow drive shaft connected to the gear mechanism and extending in the axial direction, and a fluid passage through which fluid flows. The gear housing houses the fluid. The fluid passage has a first fluid passage section connecting the inside of the gear housing and the inside of the drive shaft, a second fluid passage section connected to the first fluid passage section and at least a portion of which is formed by the inside of the drive shaft, a third fluid passage section connected to the other axial side of the second fluid passage section, and a first fluid supply section connected to the third fluid passage section and located vertically above the stator. [Effects of the Invention]

[0008] According to one aspect of the present invention, the efficiency of supplying fluid to each part of a drive device can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the drive unit of the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing the drive device of the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view of the drive device of the first embodiment, and is a view of the drive device from one side in the axial direction. [Figure 4] Figure 4 is a cross-sectional view showing a part of the drive device of the first embodiment. [Figure 5] Figure 5 is a cross-sectional view showing a part of the drive unit of the second embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view showing the drive device of the third embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view showing the drive unit of the fourth embodiment. [Figure 8] Figure 8 is a schematic cross-sectional view showing the drive unit of the fifth embodiment. [Modes for carrying out the invention]

[0010] In the following description, the vertical direction will be defined and explained based on the positional relationship when the drive unit of the embodiment is mounted on a vehicle located on a horizontal road surface. In other words, the relative positional relationship with respect to the vertical direction described in the following embodiment only needs to be satisfied when the drive unit is mounted on a vehicle located on a horizontal road surface.

[0011] In the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The side in which the Z-axis arrow points (+Z side) is the vertically upward side, and the side opposite to the side in which the Z-axis arrow points (-Z side) is the vertically downward side. In the following description, the vertically upward side will simply be referred to as the "upper side," and the vertically downward side will simply be referred to as the "lower side." The X-axis direction is perpendicular to the Z-axis direction and is the longitudinal direction of the vehicle on which the drive unit is mounted. In the following embodiments, the side in which the X-axis arrow points (+X side) is the front of the vehicle, and the side opposite to the side in which the X-axis arrow points (-X side) is the rear of the vehicle. The Y-axis direction is perpendicular to both the X-axis direction and the Z-axis direction and is the lateral direction of the vehicle, i.e., the vehicle width direction. In the following embodiment, the side indicated by the Y-axis arrow (+Y side) is the left side of the vehicle, and the side opposite to the Y-axis arrow (-Y side) is the right side of the vehicle. The longitudinal and lateral directions are horizontal directions perpendicular to the vertical direction.

[0012] Note that the front-to-back positional relationship is not limited to the positional relationship of the embodiments described below. The side in which the X-axis arrow points (+X side) may be the rear of the vehicle, and the side opposite to the side in which the X-axis arrow points (-X side) may be the front of the vehicle. In this case, the side in which the Y-axis arrow points (+Y side) is the right side of the vehicle, and the side opposite to the side in which the Y-axis arrow points (-Y side) is the left side of the vehicle. Furthermore, in this specification, "parallel direction" includes substantially parallel directions, and "orthogonal direction" includes substantially orthogonal directions.

[0013] The central axis J1, as shown in the diagrams, is a virtual axis extending in a direction intersecting the vertical direction. More specifically, the central axis J1 extends in the Y-axis direction perpendicular to the vertical direction, that is, in the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the central axis J1 will be simply called the "axial direction," the radial direction centered on the central axis J1 will be simply called the "radial direction," and the circumferential direction centered on the central axis J1, that is, around the axis of the central axis J1, will be simply called the "circumferential direction." In the following embodiments, the left side (+Y side) will be called the "axial side," and the right side (-Y side) will be called the "axial side."

[0014] <First Embodiment> The drive unit 100 of this embodiment shown in Figure 1 is a drive unit mounted on a vehicle that rotates a drive shaft 39 connected to a wheel (not shown). The vehicle on which the drive unit 100 is mounted is a vehicle powered by a motor, such as a hybrid electric vehicle (HEV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV). As shown in Figure 1, the drive unit 100 comprises a housing 10 and an inverter unit 50. As shown in Figure 2, the drive unit 100 comprises a motor 20, a gear mechanism 30, a pump 71, and a cooler 72.

[0015] The housing 10 includes a motor housing 11 that houses the motor 20, a gear housing 12 that houses the gear mechanism 30, and a partition wall 13 that separates the interior of the motor housing 11 from the interior of the gear housing 12. In this embodiment, the gear housing 12 is connected to one axial side (+Y side) of the motor housing 11. That is, the gear housing 12 is located on one axial side of the motor housing 11. The partition wall 13 separates the interior of the motor housing 11 from the interior of the gear housing 12 in the axial direction. The partition wall 13 has a hole 13a that penetrates the partition wall 13 in the axial direction. The partition wall 13 has a partition wall opening 13b that connects the interior of the motor housing 11 and the interior of the gear housing 12.

[0016] The motor housing 11 is substantially cylindrical in shape and extends in the axial direction. The motor housing 11 comprises a motor housing body 11a and a motor cover 14. In this embodiment, the motor housing body 11a and the motor cover 14 are separate components. However, the motor housing body 11a and the motor cover 14 may be parts of the same single component.

[0017] The motor housing main body 11a is a peripheral wall portion that surrounds the motor 20 around the central axis J1. The motor cover 14 is a wall portion on the other axial side (-Y side) among the wall portions constituting the motor housing 11. The motor cover 14 is located on the other axial side of the motor 20. In the present embodiment, the motor cover 14 is arranged with the inner space of the motor housing 11 interposed between the motor cover 14 and the partition wall portion 13. A holding hole 14a recessed toward the other axial side is provided on a surface on one axial side (+Y side) of the motor cover 14.

[0018] The gear housing 12 includes a gear housing main body 12a and a gear cover 15. In the present embodiment, the gear housing main body 12a and the gear cover 15 are separate members from each other. Note that the gear housing main body 12a and the gear cover 15 may be parts of the same single member.

[0019] The gear housing main body 12a is a peripheral wall portion that surrounds the gear mechanism 30 around the central axis J1. The gear cover 15 is a wall portion on one axial side (+Y side) among the wall portions constituting the gear housing 12. The gear cover 15 is located on one axial side of the gear mechanism 30. In the present embodiment, the gear cover 15 is arranged with the inner space of the gear housing 12 interposed between the gear cover 15 and the partition wall portion 13. A bottom portion 12b located on the lower side of the gear housing 12 is positioned lower than a bottom portion 11b located on the lower side of the motor housing 11. The gear cover 15 has a holding hole 15a recessed from a surface on the other axial side (-Y side) of the gear cover 15 toward one axial side (+Y side).

[0020] The gear housing 12 houses oil O as a fluid. Inside the gear housing 12, there is a first storage section 16 capable of storing oil O. In other words, the drive unit 100 includes the first storage section 16. The first storage section 16 is formed by the lower part of the gear housing 12. The interior of the first storage section 16 is the lower region inside the gear housing 12. Part of the first storage section 16 is formed by the bottom 12b of the gear housing 12. When oil O is stored in the first storage section 16, an oil reservoir P is formed in the lower region inside the gear housing 12.

[0021] The oil O flows through the flow path 90, which will be described later. In this embodiment, the oil O is used as a coolant to cool the motor 20. The oil O is also used as a lubricant for the gear mechanism 30 and the bearings, which will be described later. As for the oil O, it is preferable to use an oil equivalent to an automatic transmission fluid (ATF) with relatively low viscosity in order to perform the functions of both coolant and lubricant.

[0022] The motor 20 includes a rotor 21 that can rotate about a central axis J1, and a stator 22 that faces the rotor 21 with a gap between them. The rotor 21 includes a hollow motor shaft 23 that extends in the axial direction, a rotor core 24a fixed to the outer circumferential surface of the motor shaft 23, and a magnet 24b fixed to the rotor core 24a. The motor shaft 23 is cylindrical with the central axis J1 as its center and openings on both sides in the axial direction. The motor shaft 23 has through holes 23a that penetrate radially through the wall portion of the motor shaft 23 from the inner circumferential surface to the outer circumferential surface of the motor shaft 23. Multiple through holes 23a are provided at intervals in the circumferential direction. The inner circumferential surface of the motor shaft 23 where the through holes 23a are provided is part of the inner circumferential surface of the second flow channel 92, which will be described later.

[0023] The other axial end (-Y side) of the motor shaft 23 is supported by the motor cover 14 via a bearing 41. The other axial end (+Y side) of the motor shaft 23 is supported by the partition wall 13 via a bearing 42. The rotor 21 is rotatably supported by the bearings 41 and 42 around the central axis J1. In other words, in this embodiment, the drive unit 100 includes bearings 41 and 42 that rotatably support the motor shaft 23. Bearing 41 is held in a holding hole 14a of the motor cover 14 and supports the other axial end of the motor shaft 23. Bearing 42 is held in a hole 13a of the partition wall 13 and supports the other axial end of the motor shaft 23. Bearings 41 and 42 are, for example, ball bearings.

[0024] The stator 22 is located radially outward from the rotor 21. The stator 22 is fixed inside the motor housing 11. The stator 22 has an annular stator core 25 surrounding the rotor 21 and a plurality of coils 26 attached to the stator core 25.

[0025] The gear mechanism 30 is connected to the rotor 21. More specifically, the gear mechanism 30 is connected to one axial end (+Y side) of the motor shaft 23. The gear mechanism 30 includes a reduction gear 31 and a differential gear 32. The reduction gear 31 is connected to one axial end of the motor shaft 23. The reduction gear 31 includes a first gear shaft 33, a first gear 34, a second gear 35, a third gear 36, and a second gear shaft 37. In other words, the gear mechanism 30 includes a first gear shaft 33, a first gear 34, a second gear 35, a third gear 36, and a second gear shaft 37.

[0026] The first gear shaft 33 is connected to one axial side (+Y side) of the motor shaft 23. The first gear shaft 33 is a hollow shaft that extends in the axial direction. The first gear shaft 33 is cylindrical with its center on the central axis J1 and openings on both axial sides. The other axial end (-Y side) of the first gear shaft 33 is fitted inside the motor shaft 23. In this embodiment, the other axial end of the first gear shaft 33 is connected to one axial end of the motor shaft 23 by spline fitting. In other words, in this embodiment, the motor shaft 23 and the first gear shaft 33 are separate entities and are connected to each other by spline fitting. The first gear shaft 33 is supported so as to be rotatable around the central axis J1 by a bearing 43 held in the hole 13a of the partition wall 13 and a bearing 44 held in the holding hole 15a of the gear cover 15. Bearings 43 and 44 are, for example, ball bearings.

[0027] The first gear 34 is fixed to the outer surface of the first gear shaft 33. Thus, the first gear 34 is connected to the rotor 21 via the first gear shaft 33. The first gear shaft 33 and the first gear 34 rotate together with the rotor 21 around the central axis J1.

[0028] The second gear shaft 37 extends in the axial direction. The second gear shaft 37 is cylindrical with an intermediate axis J2 that extends in the axial direction as its center. The intermediate axis J2 is a virtual axis parallel to the central axis J1. The intermediate axis J2 is located, for example, below the central axis J1. In this embodiment, the second gear shaft 37 is a shaft provided in the gear mechanism 30 and rotates together with the second gear 35.

[0029] The second gear 35 and the third gear 36 are fixed to the outer surface of the second gear shaft 37. The second gear 35 meshes with the first gear 34. The third gear 36 meshes with the ring gear 38 of the differential 32, which will be described later. The rotational speed of the first gear shaft 33 and the first gear 34 are the same as the rotational speed of the rotor 21. The rotational speed of the second gear 35, the third gear 36, and the second gear shaft 37 are smaller than the rotational speed of the rotor 21.

[0030] The differential gear 32 has a ring gear 38. Torque output from the motor 20 is transmitted to the ring gear 38 via the reduction gear 31. The lower end of the ring gear 38 is located inside the first reservoir 16. The lower end of the ring gear 38 is the lower end of the gear mechanism 30. In other words, in this embodiment, the lower end of the gear mechanism 30 is located inside the first reservoir 16. As a result, the lower end of the ring gear 38 is immersed in the oil reservoir P provided in the first reservoir 16. As the ring gear 38 rotates, the oil O in the oil reservoir P is stirred up. The stirred-up oil O is supplied as lubricant to the reduction gear 31 and the differential gear 32, for example. The differential gear 32 rotates the drive shaft 39 around the differential shaft J3. The differential shaft J3 is a virtual shaft extending parallel to the central axis J1.

[0031] In this embodiment, the drive unit 100 is equipped with a passage 90 through which oil O flows. In this embodiment, the passage 90 is an oil passage through which oil O flows. The passage 90 includes a first passage section 91, a second passage section 92, a third passage section 93, a first fluid supply section 94, and a rotor core internal passage section 95.

[0032] The first flow path section 91 is a flow path section that connects the inside of the gear housing 12 and the inside of the first gear shaft 33. In this embodiment, the first flow path section 91 is provided in the gear cover 15. The first flow path section 91 has a first connecting flow path section 91a that connects the inside of the first storage section 16 and the pump 71, a second connecting flow path section 91b that connects the pump 71 and the cooler 72, and a third connecting flow path section 91c that connects the cooler 72 and the inside of the first gear shaft 33.

[0033] As shown in Figure 3, one end of the first connecting channel section 91a is connected to the inside of the first storage section 16. The other end of the first connecting channel section 91a is located above and behind (-X side) the one end of the first connecting channel section 91a and is connected to the pump 71. The third connecting channel section 91c extends forward (+X side) and diagonally upward from the cooler 72 and is connected to the inside of the first gear shaft 33.

[0034] As shown in Figure 2, the second flow path section 92 is a flow path section in which at least a portion is formed by the inside of the first gear shaft 33 and the inside of the motor shaft 23. In this embodiment, the entirety of the second flow path section 92 is formed by the inside of the first gear shaft 33 and the inside of the motor shaft 23. The second flow path section 92 extends in the axial direction. The second flow path section 92 is connected to the first flow path section 91. More specifically, one end of the second flow path section 92 on one axial side (+Y side) is connected to the upper end of the third connecting flow path section 91c via a retaining hole 15a provided in the gear cover 15.

[0035] The third flow path section 93 is a flow path section connected to the axially opposite (-Y side) portion of the second flow path section 92. In this embodiment, the third flow path section 93 is connected to the axially opposite end of the second flow path section 92 via a retaining hole 14a provided in the motor cover 14. In this embodiment, the third flow path section 93 is provided in the motor cover 14. The third flow path section 93 extends in the vertical direction. The third flow path section 93 extends upward from the axially opposite end of the second flow path section 92. As shown in Figure 4, the flow path cross-sectional area of ​​the third flow path section 93 is smaller than the flow path cross-sectional area of ​​the second flow path section 92. In other words, in this embodiment, the flow path cross-sectional area of ​​the second flow path section 92 is larger than the flow path cross-sectional area of ​​the third flow path section 93.

[0036] As shown in Figure 2, the first fluid supply unit 94 is located inside the motor housing 11. The first fluid supply unit 94 is located vertically above the stator 22. In this embodiment, the first fluid supply unit 94 is a tubular member extending in the axial direction. The first fluid supply unit 94 is, for example, a cylindrical pipe opening on both sides in the axial direction. One end of the first fluid supply unit 94 (+Y side) in the axial direction is held by the partition wall 13. The other end of the first fluid supply unit 94 (-Y side) in the axial direction is held by the motor cover 14. The first fluid supply unit 94 is connected to the third flow path 93. More specifically, the other end of the first fluid supply unit 94 in the axial direction is connected to the upper end of the third flow path 93. As shown in Figure 4, the flow path cross-sectional area of ​​the first fluid supply unit 94 is, for example, the same as the flow path cross-sectional area of ​​the third flow path 93.

[0037] The first fluid supply unit 94 has a plurality of supply ports 94a. The supply ports 94a open downwards. In this embodiment, each supply port 94a is made up of a hole provided in the lower part of the wall of the pipe member constituting the first fluid supply unit 94. The oil O in the first fluid supply unit 94 is discharged from the plurality of supply ports 94a and supplied to the stator 22 from above. In this way, the first fluid supply unit 94 supplies oil O to the stator 22.

[0038] The internal flow channel 95 of the rotor core is provided in the rotor core 24a. The internal flow channel 95 of the rotor core is connected to the second flow channel 92 via a through hole 23a. The internal flow channel 95 of the rotor core opens at both axial ends of the rotor core 24a.

[0039] The flow path 90 has a second fluid supply section 96 that supplies oil O to a bearing 41 that rotatably supports the motor shaft 23. In this embodiment, the second fluid supply section 96 is made up of a hole that penetrates the wall portion of the motor shaft 23 radially from the inner circumferential surface of the motor shaft 23 to the outer circumferential surface of the motor shaft 23. Multiple second fluid supply sections 96 are provided at intervals in the circumferential direction. The second fluid supply section 96 is provided on the portion of the motor shaft 23 that is held by the bearing 41. The second fluid supply section 96 is connected to the second flow path section 92. The second fluid supply section 96 opens into the holding hole portion 14a.

[0040] In this specification, "two flow channels are connected" means that it is possible for fluid to flow from one of the two flow channels to the other.

[0041] As shown in Figure 2, the pump 71 and the cooler 72 are attached to the gear cover 15 of the gear housing 12. In this embodiment, the pump 71 is an electric pump that supplies oil O. The cooler 72 is provided in the first flow path section 91. More specifically, the cooler 72 is provided between the second connecting flow path section 91b and the third connecting flow path section 91c. Part of the refrigerant circulation path 60 passes through the cooler 72. The refrigerant circulation path 60 is a flow path through which the refrigerant circulates. The refrigerant flowing in the refrigerant circulation path 60 is, for example, water. The refrigerant circulation path 60 returns to the radiator, passing from a radiator (not shown) through the inverter unit 50 and the cooler 72 in that order. The cooler 72 cools the oil O flowing in the first flow path section 91 by heat exchange with the refrigerant flowing in the refrigerant circulation path 60.

[0042] When the pump 71 is driven, oil O from the oil reservoir P is drawn into the passage 90 from the lower end of the first passage section 91. The oil O drawn into the passage 90 flows through the first connecting passage section 91a, the pump 71, the second connecting passage section 91b, the cooler 72, and the third connecting passage section 91c in that order, and flows into the axial end (+Y side) of the second passage section 92. The oil O that has flowed into the second passage section 92 flows in the other axial direction (-Y direction) within the second passage section 92, and flows from inside the gear housing 12 into the motor housing 11.

[0043] A portion of the oil O that flows into the second flow path section 92 is supplied to the portion where the motor shaft 23 and the first gear shaft 33 are spline-fitted. Another portion of the oil O that flows into the second flow path section 92 flows into the rotor core internal flow path section 95 through the through hole 23a. The oil O that flows into the rotor core internal flow path section 95 is scattered radially outward from both axial ends of the rotor core 24a and supplied to the coil 26. This allows the rotor 21 and stator 22 to be cooled with oil O. Yet another portion of the oil O that flows into the second flow path section 92 is supplied to the bearing 41 from the second fluid supply section 96. This allows the bearing 41 to be supplied with oil O as lubricant. The remaining portion of the oil O that flows into the second flow path section 92 flows into the third flow path section 93. The oil O that flows into the third flow path section 93 flows into the first fluid supply section 94.

[0044] The oil O that flows into the first fluid supply unit 94 is discharged into the motor housing 11 from multiple supply ports 94a. The oil O discharged from the multiple supply ports 94a is supplied to the stator 22. This allows the stator 22 to be cooled more effectively by the oil O. The oil O supplied to the stator 22 from the rotor core internal flow path 95, the oil O supplied to the bearing 41 from the second fluid supply unit 96, and the oil O supplied to the stator 22 from the supply ports 94a all fall downwards and accumulate in the lower region of the motor housing 11. The oil O accumulated in the lower region of the motor housing 11 returns to the gear housing 12 through the partition wall opening 13b provided in the partition wall 13.

[0045] According to this embodiment, the flow path 90 includes a first flow path section 91 connecting the inside of the gear housing 12 and the inside of the first gear shaft 33, a second flow path section 92 connected to the first flow path section 91 and at least a portion of which is composed of the inside of the first gear shaft 33 and the inside of the motor shaft 23, a third flow path section 93 connected to the other axial side portion of the second flow path section 92, and a first fluid supply section 94 connected to the third flow path section 93 and located on the vertically upper side of the stator 22. In other words, the first flow path section 91, the second flow path section 92, the third flow path section 93, and the first fluid supply section 94 are all connected in one unit. Therefore, a single pump 71 can sequentially supply oil O to each flow path section, including the inside of the motor shaft 23 and the first fluid supply section 94 located on the upper side of the stator 22. This allows for more efficient supply of oil O to each part of the drive unit 100 compared to the case where multiple pumps 71 are used.

[0046] Furthermore, compared to a case where, for example, the oil O supplied from the first fluid supply unit 94 to the stator 22 flows into the second flow path unit 92, it is possible to make it easier for the oil O to flow into the second flow path unit 92, which is composed of each shaft, via the first flow path unit 91 or the third flow path unit 93. Also, the temperature of the oil O after it has been supplied to the stator 22 varies depending on the amount of heat generated by the stator 22, etc. Therefore, the viscosity of the oil O after it has been supplied to the stator 22 also varies depending on the amount of heat generated by the stator 22, etc. As a result, when the oil O supplied to the stator 22 flows into the second flow path unit 92, the viscosity of the oil O after it has been supplied to the stator 22 causes variations in the flow rate of the oil O flowing into the second flow path unit 92. In contrast, in this embodiment, since the oil O before it is supplied to the stator 22 is supplied to the second flow path unit 92, the flow rate of the oil O supplied to the second flow path unit 92 can be stabilized.

[0047] Furthermore, for example, when oil O flows through a branched flow path 92 and a first fluid supply unit 94, the ratio of the flow rate of oil O supplied to the second flow path 92 to the flow rate of oil O supplied to the first fluid supply unit 94 may change due to changes in the viscosity of the oil O. Specifically, for example, the flow rate of oil O supplied from the first fluid supply unit 94 to the stator 22 via the supply port 94a is easily affected by the viscosity of the oil O. Therefore, when oil O flows through a branched flow path 92 and a first fluid supply unit 94, changes in the viscosity of the oil O may cause a change in the flow rate of oil O flowing to the first fluid supply unit 94, potentially causing fluctuations in the flow rate of oil O flowing to the second flow path 92. In contrast, according to this embodiment, the second flow path 92 and the first fluid supply unit 94 are connected by a third flow path 93, forming a single continuous flow path. Therefore, even if the viscosity of the oil O changes, fluctuations in the flow rate of oil O supplied to the second flow path 92 can be suppressed.

[0048] As a result, the efficiency of supplying oil O to each part of the drive unit 100 can be improved. Furthermore, the flow rate of oil O supplied to each part of the drive unit 100 can be easily controlled. In addition, since it is not necessary to provide multiple pumps 71, the number of parts in the drive unit 100 can be reduced. Moreover, the complexity of the flow path 90 can be suppressed compared to cases where branching flow path sections are provided. Therefore, the man-hours required to create the flow path 90 can be reduced. This reduces the manufacturing cost of the drive unit 100.

[0049] Furthermore, according to this embodiment, the pump 71 flows the oil O into the flow path 90 in the direction that the oil O flows from the second flow path section 92 through the third flow path section 93 to the first fluid supply section 94. Therefore, the oil O supplied by the pump 71 flows through the second flow path section 92 before the first fluid supply section 94. This makes it easier for the relatively low-temperature oil O cooled by the cooler 72 to flow into the second flow path section 92, especially when a cooler 72 is provided near the pump 71, as in this embodiment. Consequently, it is easier for the relatively low-temperature oil O to flow into the motor shaft 23, making it easier to cool the rotor 21. This makes it easier to cool the magnet 24b of the rotor 21, and prevents the magnet 24b from becoming too hot. This prevents the magnet 24b from demagnetizing. Consequently, it is possible to prevent a decrease in the output torque of the motor 20. As a result, it is possible to maintain the output torque of the motor 20 even when using an inexpensive magnet with relatively low magnetic force as the magnet 24b. Therefore, the manufacturing cost of the drive unit 100 can be reduced by using an inexpensive magnet 24b while maintaining the output of the drive unit 100. In this embodiment, since a rotor core internal flow channel 95 connected to the second flow channel 92 is provided, relatively low-temperature oil O can be flowed from the second flow channel 92 to the rotor core internal flow channel 95, thereby more effectively cooling the magnet 24b fixed to the rotor core 24a.

[0050] Furthermore, according to this embodiment, the motor shaft 23 has a through hole 23a that penetrates the wall portion of the motor shaft 23 radially from the inner circumferential surface of the second flow channel 92 to the outer circumferential surface of the motor shaft 23. Therefore, a portion of the oil O flowing through the second flow channel 92 can be supplied to the radially outer side of the motor shaft 23 through the through hole 23a. This makes it easier to cool the rotor core 24a and magnet 24b fixed to the motor shaft 23 with the oil O.

[0051] Furthermore, according to this embodiment, the cross-sectional area of ​​the second flow path section 92 is larger than the cross-sectional area of ​​the third flow path section 93. Therefore, the flow rate of oil O flowing through the second flow path section 92 can be increased. This allows for an increased flow rate of oil O flowing from the second flow path section 92 to the radially outer side of the motor shaft 23 through the through hole 23a. Consequently, the rotor core 24a and magnet 24b can be more easily cooled by the oil O.

[0052] Furthermore, according to this embodiment, the motor shaft 23 and the first gear shaft 33 are separate entities and are connected to each other by spline fitting. Therefore, a portion of the oil O flowing through the second flow path 92 can be supplied to the spline fitting portion between the motor shaft 23 and the first gear shaft 33. This makes it easier to maintain a well-connected state between the motor shaft 23 and the first gear shaft 33. In addition, the oil O supplied to the spline fitting portion between the motor shaft 23 and the first gear shaft 33 can also be supplied to the bearings supporting each shaft. Specifically, in this embodiment, the oil O supplied to the spline fitting portion between the motor shaft 23 and the first gear shaft 33 flows into the hole 13a and is supplied to the bearings 42 and 43 held in the hole 13a.

[0053] Furthermore, according to this embodiment, the flow path 90 has a second fluid supply section 96 that supplies oil O to the bearing 41. Therefore, oil O can be suitably supplied to the bearing 41 as a lubricant. The flow path 90 may also have a second fluid supply section that supplies oil O to other bearings 42, 43, and 44, or a second fluid supply section that supplies oil O to the bearing supporting the second gear shaft 37.

[0054] Furthermore, according to this embodiment, the first fluid supply unit 94 is a tubular member extending in the axial direction. Therefore, the first fluid supply unit 94 is easy to manufacture. Also, it is easy to pump oil O into the first fluid supply unit 94. Therefore, it is possible to suitably supply oil O to the first fluid supply unit 94.

[0055] Furthermore, according to this embodiment, the cooler 72 is provided in the first flow path section 91. Therefore, the cooler 72 can cool the oil O flowing through the first flow path section 91. As a result, when the oil O flows in the direction from the first flow path section 91 to the second flow path section 92, as in this embodiment, the oil O that has just been cooled by the cooler 72 in the first flow path section 91 can flow into the second flow path section 92. Therefore, the temperature of the oil O flowing inside the motor shaft 23 can be suitably lowered. This allows for more suitable cooling of the rotor 21. Consequently, the magnet 24b can be cooled more suitablely.

[0056] <Second Embodiment> Hereafter, the same components as those in the embodiments described above may be omitted from explanation by using the same reference numerals as appropriate. As shown in Figure 5, in the drive device 200 of this embodiment, the inner diameter of the hollow motor shaft 223 is smaller than the inner diameter of the motor shaft 23 in the first embodiment. The cross-sectional area of ​​the second flow path section 292 in the flow path 290 is smaller than the cross-sectional area of ​​the second flow path section 92 in the first embodiment. The cross-sectional area of ​​the third flow path section 293 is larger than the cross-sectional area of ​​the third flow path section 93 in the first embodiment. The cross-sectional area of ​​the first fluid supply section 294 is larger than the cross-sectional area of ​​the first fluid supply section 94 in the first embodiment.

[0057] The cross-sectional area of ​​the second flow path section 292 is smaller than the cross-sectional area of ​​the third flow path section 293. Therefore, it is easier to reduce the flow rate of oil O flowing through the second flow path section 292, and thus reduce the flow rate of oil O flowing from the second flow path section 292 through the through hole 23a to the rotor core internal flow path section 95. This allows for a relatively larger flow rate of oil O flowing from the third flow path section 293 to the first fluid supply section 294. Consequently, the flow rate of oil O supplied from the first fluid supply section 294 to the stator 22 can be increased. The other configurations of the drive unit 200 are the same as those of the drive unit 100 in the first embodiment.

[0058] <Third Embodiment> In the following, the same components as those in the embodiments described above may be omitted from explanation by using the same reference numerals as appropriate. As shown in Figure 6, in the flow path 390 of the drive device 300 of this embodiment, the first fluid supply unit 394 is a trough-shaped member that opens vertically upward. Therefore, even in cases where it is difficult to supply oil O to the stator 22 from a tubular member, such as when the viscosity of the oil O is high and it is difficult to pump the oil O, it is easy to suitably supply oil O to the stator 22 from the supply port 394a of the first fluid supply unit 394.

[0059] The end of the third flow path section 393 opposite to the side connected to the second flow path section 92 is an opening 393a that opens into the motor housing 11. The opening 393a is provided in the upper wall portion of the wall portion that constitutes the motor housing 11. The opening 393a is located above the first fluid supply section 394. The opening 393a opens downwards. The oil O in the third flow path section 393 discharged from the opening 393a is supplied into the first fluid supply section 394 from above. The oil O is stored in the first fluid supply section 394. The oil O stored in the first fluid supply section 394 flows along the trough-shaped first fluid supply section 394 and is supplied to the stator 22 from the supply port 394a. The other configurations of the drive unit 300 are the same as the other configurations of the drive unit 100 of the first embodiment.

[0060] <Fourth Embodiment> In the following description, components similar to those in the embodiments described above may be omitted from explanation by using the same reference numerals as appropriate. As shown in Figure 7, the drive unit 400 of this embodiment includes a second storage section 480 provided in the gear housing 12. The second storage section 480 is located above the first storage section 16. In this embodiment, the second storage section 480 is located above the gear mechanism 30. The second storage section 480 opens upwards. The second storage section 480 is, for example, trough-shaped. At least a portion of the oil O scooped up by the ring gear 38 is stored inside the second storage section 480. The second storage section 480 has a supply port 481.

[0061] The second storage section 480 is provided in the flow path 490. The supply port 481 of the second storage section 480 is connected to the first flow path section 491 of the flow path 490. In this embodiment, the first flow path section 491 connects the second storage section 480 and the second flow path section 92.

[0062] In this embodiment, the pump 471 is a mechanical pump. The pump 471 is connected to the other axial end (-Y side) of the motor shaft 23. The pump 471 has an annular inner rotor 471a fixed to the outer circumferential surface of the motor shaft 23, and an annular outer rotor 471b surrounding the inner rotor 471a radially outward. The inner rotor 471a and the outer rotor 471b are provided in a pump chamber 471c provided in the motor cover 14. The inner rotor 471a and the outer rotor 471b mesh with each other via teeth (not shown).

[0063] As the motor shaft 23 rotates, the inner rotor 471a rotates around the central axis J1, causing the outer rotor 471b to also rotate. This draws the oil O in the second reservoir 480 into the first flow path 491. The oil O drawn into the first flow path 491 flows through the first flow path 491 and the second flow path 92 in that order, and flows into the gap between the inner rotor 471a and the outer rotor 471b via the holding hole 14a. The oil O that has flowed into the gap between the inner rotor 471a and the outer rotor 471b moves circumferentially as the inner rotor 471a and the outer rotor 471b rotate, and is discharged into the third flow path 493. In other words, in this embodiment, the third flow path 493 is connected to the second flow path 92 via the pump 471. The other configurations of the drive unit 400 are the same as the other configurations of the drive unit 100 in the first embodiment.

[0064] According to this embodiment, the drive unit 400 includes a second storage section 480 located inside the gear housing 12 and capable of storing oil O. The second storage section 480 is located vertically above the first storage section 16 and is provided in the flow path 490. Therefore, a portion of the oil O contained in the gear housing 12 can be stored in the second storage section 480, relatively reducing the amount of oil O stored in the first storage section 16. This lowers the liquid level of the oil reservoir P in the first storage section 16. Consequently, even if the height difference between the bottom 11b of the motor housing 11 and the bottom 12b of the gear housing 12 is small, it is easier to return the oil O supplied to the motor housing 11 by the flow path 490 back into the gear housing 12.

[0065] Furthermore, according to this embodiment, the first flow channel 491 connects the second storage section 480 and the second flow channel 92. The second storage section 480 opens to the upper side in the vertical direction. The lower end of the gear mechanism 30 in the vertical direction is located within the first storage section 16. Therefore, a portion of the oil O in the first storage section 16 that is stirred up by the gear mechanism 30 can be stored in the second storage section 480. In addition, the oil O stored in the second storage section 480 can be flowed to the second flow channel 92 via the first flow channel 491. This lowers the liquid level of the oil reservoir P in the first storage section 16, making it easier to return the oil O to the gear housing 12, while also allowing the oil O to be suitably delivered to the motor housing 11 via the second flow channel 92.

[0066] <Fifth Embodiment> In the following, components similar to those in the embodiments described above may be omitted from explanation by using the same reference numerals as appropriate. As shown in Figure 8, in the housing 510 of the drive unit 500, the bottom 511b of the motor housing 511 is located below the bottom 512b of the gear housing 512. An oil reservoir P1 is provided below the flow path member 597, which will be described later, in the motor housing 511. An oil reservoir P2 is provided in the lower region of the gear housing 512. The oil reservoirs P1 and P2 are connected to each other via the partition opening 13b of the partition wall 13. A part of the motor 20 may be immersed in the oil O of the oil reservoir P1.

[0067] In the gear mechanism 530, the first gear shaft 533 of the reduction gear 531 is a hollow shaft that opens on both axial sides. The second gear 535 and the third gear 536 can be switched between being connected to each other and being disconnected by a clutch mechanism 573. The second gear 535 meshes with the first gear 34 which is connected to the rotor 21. The second gear 535 is rotatable about an intermediate shaft J2 which is radially positioned differently from the central shaft J1. In this embodiment, the intermediate shaft J2 is located above the central shaft J1. The third gear 536 is rotatable about the intermediate shaft J2 together with the second gear 535 when connected to the second gear 535 via the clutch mechanism 573.

[0068] The drive unit 500 includes a drive shaft 539 connected to a gear mechanism 530. The drive shaft 539 is a hollow shaft extending in the axial direction. The drive shafts 539 are provided on both the axial sides of the differential 532. Each drive shaft 539 is connected to a vehicle wheel H. The drive shaft 539 extending from the differential 532 to the other axial side (-Y side) passes through the inside of the first gear shaft 533 and the inside of the motor shaft 23. In this embodiment, the differential axis J3 of the differential 532 coincides with the central axis J1 of the motor 20. In this embodiment, the ring gear 38 of the differential 532 corresponds to the fourth gear that meshes with the third gear 536.

[0069] The drive unit 500 includes a flow path member 597 located within the motor housing 511. The flow path member 597 is located radially outward from the stator 22. The flow path member 597 is cylindrical and surrounds the stator 22. The flow path member 597 is fixed to the inner circumferential surface of the motor housing 11. The flow path member 597 is provided with a refrigerant flow path 597a through which a refrigerant flows. The refrigerant flowing through the refrigerant flow path 597a is, for example, water. In other words, the flow path member 597 is, for example, a water jacket. A refrigerant inlet passage 561 and a refrigerant outlet passage 562 extending from a radiator (not shown) are connected to the refrigerant flow path 597a. Refrigerant cooled by the radiator (not shown) flows into the refrigerant flow path 597a from the refrigerant inlet passage 561. The refrigerant flowing through the refrigerant flow path 597a can cool the stator 22. The refrigerant in the refrigerant flow path 597a flows out into the refrigerant outlet passage 562 and returns to the radiator (not shown).

[0070] In this embodiment, the flow path 590 through which oil O flows has a first flow path section 591, a second flow path section 592, a third flow path section 593, a fourth flow path section 594, and a first fluid supply section 595. The first flow path section 591 is a flow path section that connects the inside of the gear housing 12 and the inside of the drive shaft 539. In this embodiment, the first flow path section 591 connects the inside of the first storage section 16, which is provided with an oil reservoir P2, and the inside of the drive shaft 539, which extends from the differential gear 532 in one axial direction (+Y side). The first flow path section 591 opens into the oil reservoir P2. A pump 571 and a cooler 572 are provided in the middle of the first flow path section 591. The pump 571 is an electric pump. In this embodiment, the pump 571 and the cooler 572 are attached to the gear housing 512. More specifically, the pump 571 and the cooler 572 are attached to the wall portion of the gear housing 512 located on one axial side, i.e., the gear cover 15.

[0071] The second flow path section 592 is a flow path section in which at least a portion is formed by the inside of the drive shaft 539. In this embodiment, the second flow path section 592 is formed by the inside of the drive shaft 539 on one axial side (+Y side), the inside of the differential 532, and the inside of the drive shaft 539 on the other axial side (-Y side). The axial end of the second flow path section 592 is connected to the first flow path section 591.

[0072] The third flow path section 593 is a flow path section connected to the axially opposite (-Y side) portion of the second flow path section 592. In this embodiment, the third flow path section 593 connects the axially opposite end of the second flow path section 592 to the axially opposite end of the first fluid supply section 595. In this embodiment, the third flow path section 593 is provided in the motor housing 511. More specifically, the third flow path section 593 is provided in the motor cover 14. In this embodiment, the motor cover 14 corresponds to the axial wall portion located on the axially opposite side of the stator 22.

[0073] The fourth fluid passage section 594 is a fluid passage section that connects the inside of the motor housing 511 to the first fluid supply section 595. The fourth fluid passage section 594 opens into the oil reservoir P1. In this embodiment, the fourth fluid passage section 594 is provided in the motor cover 14. A portion of the oil O flowing through the fourth fluid passage section 594 is supplied to a bearing that rotatably supports the motor shaft 23. A mechanical pump 574 is provided in the fourth fluid passage section 594. The mechanical pump 574 is connected to the drive shaft 539 on the other axial side (-Y side).

[0074] The first fluid supply unit 595 is located above the stator 22. In this embodiment, the first fluid supply unit 595 is provided on the upper wall of the motor housing 511. The first fluid supply unit 595 extends in the axial direction. The first fluid supply unit 595 is connected to the third flow path 593 and the fourth flow path 594. More specifically, the upper end of the third flow path 593 and the upper end of the fourth flow path 594 are connected to the other axial end (-Y side) of the first fluid supply unit 595. The first fluid supply unit 595 has a supply port for supplying oil O to the bearings supporting the stator 22 and the motor shaft 23.

[0075] When the drive shaft 539 is driven, the mechanical pump 574 is driven. When the mechanical pump 574 is driven, oil O from the oil reservoir P1 in the motor housing 511 is drawn into the fourth flow path section 594. The oil O drawn into the fourth flow path section 594 flows upward through the fourth flow path section 594 and flows into the first fluid supply section 595. The oil O that flows into the first fluid supply section 595 is supplied to the bearings supporting the stator 22 and the motor shaft 23.

[0076] When the pump 571 is driven, the oil O in the first reservoir 16, i.e., the oil O in the oil reservoir P2, flows into the first flow path 591. The oil O that flows into the first flow path 591 flows through the cooler 572 and the pump 571 in that order and flows into the axial end (+Y side) of the second flow path 592. The oil O that flows into the second flow path 592 flows to the other axial side (-Y side), passes through the third flow path 593, and flows into the first fluid supply unit 595. The oil O that flows into the first fluid supply unit 595 is supplied to the bearings supporting the stator 22 and the motor shaft 23. The other configurations of the drive unit 500 can be the same as the other configurations of the drive unit 100 of the first embodiment.

[0077] According to this embodiment, the flow path 590 includes a first flow path section 591 connecting the inside of the gear housing 512 and the inside of the drive shaft 539, a second flow path section 592 which is at least partly composed of the inside of the drive shaft 539 and connected to the first flow path section 591, a third flow path section 593 which is connected to the other axial side portion of the second flow path section 592, and a first fluid supply section 595 which is connected to the third flow path section 593 and located on the vertically upper side of the stator 22. In other words, the first flow path section 591, the second flow path section 592, the third flow path section 593, and the first fluid supply section 595 are connected as one unit. Therefore, as in the embodiment described above, oil O can be sequentially supplied to each flow path section, including the inside of the drive shaft 539, by a single pump 571. This makes it possible to efficiently supply oil O to each part of the drive device 500.

[0078] Furthermore, according to this embodiment, the drive shaft 539 is routed through the inside of the hollow motor shaft 23. Therefore, the second flow path 592, which is at least partially formed by the inside of the drive shaft 539, can be suitably arranged within the housing 510. This makes it easier to suitably supply the oil O in the gear housing 512 to the first fluid supply unit 595 via the second flow path 592. In addition, the drive unit 500 can be made smaller compared to the case where the drive shaft 539 is not routed through the inside of the motor shaft 23.

[0079] Furthermore, according to this embodiment, the gear mechanism 530 includes a first gear 34 connected to the rotor 21, a second gear 535 that is rotatable around an intermediate shaft J2 which is radially positioned differently from the central shaft J1 and meshes with the first gear 34, a third gear 536 that is rotatable together with the second gear 535 around the intermediate shaft J2, and a ring gear 38 which acts as a fourth gear and meshes with the third gear 536, and a differential device 532 that rotates the drive shaft 539 around the differential shaft J3. The differential shaft J3 coincides with the central shaft J1. Therefore, the drive shaft 539 can be easily and suitably passed inside the hollow motor shaft 23.

[0080] Furthermore, according to this embodiment, the pump 571 and the cooler 572 are attached to the gear housing 512. Therefore, the pump 571 makes it easier to send the oil O inside the gear housing 512 into the drive shaft 539. Also, the cooler 572 makes it easier to cool the oil O that is sent from inside the gear housing 512 into the drive shaft 539.

[0081] Furthermore, according to this embodiment, the third flow path section 593 is provided in the motor housing 511. Therefore, the third flow path section 593 can be created without providing separate components such as pipe members. This helps to suppress an increase in the number of parts of the drive unit 500.

[0082] Furthermore, according to this embodiment, the third flow path 593 is provided in the motor cover 14, which is an axial wall located on the other axial side (-Y side) of the stator 22. Therefore, it is easy to connect the inside of the drive shaft 539, which penetrates the motor cover 14 in the axial direction, to the third flow path 593. This makes it easy to connect the second flow path 592 to the third flow path 593.

[0083] Furthermore, according to this embodiment, the third flow channel 593 connects the axial opposite end (-Y side) of the second flow channel 592 to the axial opposite end of the first fluid supply unit 595. Therefore, the third flow channel 593 facilitates the connection between the second flow channel 592 and the first fluid supply unit 595.

[0084] Furthermore, according to this embodiment, the flow path 590 has a fourth flow path section 594 that connects the inside of the motor housing 511 to the first fluid supply unit 595. Therefore, the oil O inside the motor housing 511 can be sent to the first fluid supply unit 595 via the fourth flow path section 594. This makes it possible to supply oil O to the first fluid supply unit 595 from both the third flow path section 593 and the fourth flow path section 594. Thus, oil O can be suitably supplied to the first fluid supply unit 595.

[0085] The present invention is not limited to the embodiments described above, and other configurations and methods may be adopted within the scope of the technical idea of ​​the present invention.

[0086] The flow path may have any configuration as long as it includes a first flow path section, a second flow path section, a third flow path section, and a first fluid supply section. The fluid may flow in any direction within the flow path. For example, a pump supplying fluid may flow the fluid through the flow path in a direction such that the fluid flows from the first fluid supply section through the third flow path section to the second flow path section. The fluid flowing through the flow path may be of any type.

[0087] The applications of the drive unit to which the present invention is applied are not particularly limited. The drive unit may be mounted on a vehicle for purposes other than rotating a drive shaft connected to a wheel, for example, or it may be mounted on equipment other than a vehicle. The orientation of the drive unit when it is used is not particularly limited. The central axis of the motor may be inclined with respect to a horizontal direction perpendicular to the vertical direction, or it may extend in the vertical direction. The configurations described herein can be combined as appropriate, within the bounds of mutual non-inconsistency. [Explanation of Symbols]

[0088] 10,510…Housing, 11,511…Motor housing, 12b,512b…Bottom, 12,512…Gear housing, 14…Motor cover (axial wall), 16…First reservoir, 20…Motor, 21…Rotor, 22…Stator, 23,223…Motor shaft, 23a…Through hole, 30,530…Gear mechanism, 33…First gear shaft (gear shaft), 34…First gear, 35,535…Second gear, 36,536…Third gear, 38…Ring gear (fourth gear), 39,539…Drive shaft, 4 1,42,43,44…Bearings, 71,471,571…Pumps, 72,572…Coolers, 90,290,390,490,590…Flow channels, 91,491,591…First flow channel section, 92,292,592…Second flow channel section, 93,293,393,493,593…Third flow channel section, 94,294,394,595…First fluid supply section, 96…Second fluid supply section, 100,200,300,400,500…Drive unit, 480…Second storage section, 594…Fourth flow channel section, J1…Central shaft, J2…Intermediate shaft, J3…Differential shaft

Claims

1. A motor having a rotor that can rotate about a central axis and a stator that faces the rotor with a gap between them, A gear mechanism connected to the rotor, A motor housing that houses the motor inside, and a housing having a gear housing located on one axial side of the motor housing that houses the gear mechanism inside, A fluid channel through which fluid flows, A first storage section is provided inside the gear housing and capable of storing the fluid, Equipped with, The rotor has a hollow motor shaft extending in the axial direction, The gear mechanism has a hollow gear shaft connected to one axial side of the motor shaft, The gear housing has a gear cover that covers the gear mechanism from one axial side, and contains the fluid inside. The aforementioned flow path is A first flow path section connecting the inside of the gear housing and the inside of the gear shaft, At least a portion of it is composed of the inside of the gear shaft and the inside of the motor shaft, and a second flow path is connected to the first flow path, A third flow channel is connected to the portion of the second flow channel that is on the other axial side, A first fluid supply unit is connected to the third flow path and located above the stator, It has, At least a portion of the first flow path is provided inside the gear cover, A portion of the first storage section is formed by the bottom of the gear housing, A drive device wherein the portion of the first flow path provided inside the gear cover has a portion located below the gear shaft.

2. The system includes a pump that supplies the aforementioned fluid, The drive device according to claim 1, wherein the pump flows the fluid through the flow path in a direction such that the fluid flows from the second flow path through the third flow path to the first fluid supply section.

3. The drive device according to claim 1, wherein the first flow path section is provided with a pump for supplying the fluid.

4. The drive device according to claim 2, wherein the pump is provided in the first flow path section.

5. The gear housing is provided with a second storage section capable of storing the fluid, The drive device according to any one of claims 1 to 4, wherein the second storage section is located above the first storage section and is provided in the flow path.

6. The first flow channel connects the second storage section and the second flow channel section. The second storage section opens upward, The drive device according to claim 5, wherein the lower end of the gear mechanism is located within the first storage section.

7. The drive device according to any one of claims 1 to 6, wherein the motor shaft has a through hole that penetrates the wall portion of the motor shaft radially from the inner surface of the second flow path portion to the outer surface of the motor shaft.

8. The drive device according to claim 7, wherein the cross-sectional area of ​​the second flow channel is larger than the cross-sectional area of ​​the third flow channel.

9. The drive device according to claim 7, wherein the cross-sectional area of ​​the second flow channel is smaller than the cross-sectional area of ​​the third flow channel.

10. The drive device according to any one of claims 1 to 9, wherein the motor shaft and the gear shaft are separate entities and are connected to each other by spline fitting.

11. The motor shaft is provided with a bearing that rotatably supports it, The drive device according to any one of claims 1 to 10, wherein the flow path has a second fluid supply unit that supplies the fluid to the bearing.

12. The drive device according to any one of claims 1 to 11, wherein the first fluid supply unit is a tubular member extending in the axial direction.

13. The drive device according to any one of claims 1 to 11, wherein the first fluid supply unit is a trough-shaped member that opens upward.

14. The system includes a cooler for cooling the aforementioned fluid, The cooler is provided in the first flow path section, the drive device according to any one of claims 1 to 13.

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