Drive unit

Abstract

To reduce the weight of a drive device.SOLUTION: A transmission mechanism housing 12 of a drive device is fixed to one axial side of a motor housing 11. The motor housing 11 has: a first housing member 13; and a second housing member 14 fixed to the other axial side of the first housing member. The transmission mechanism housing 12 has: a third housing member 15 fixed to the first housing member 13; and a fourth housing member 16 fixed to one axial side of the third housing member 15. The second housing member 14 and the third housing member 15 are fixed to the first housing member 13 by a first bolt 10a and a second bolt 10b from the other axial side. The fourth housing member is fixed to the third housing member 15 by a third bolt 10c from one axial side.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] 2. Description of the Related Art A rotating electric machine is known that has a housing that accommodates an electric motor therein and a coolant passage in the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-225987 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above rotating electric machine, the housing is composed of a front cover, a rear cover, and a main body. Screw holes are provided on one axial side and the other axial side of the main body, and the front cover and the rear cover are attached with bolts (not shown). On the other hand, in a drive unit for an electric vehicle, the motor housing and the transmission mechanism housing of the rotating electric machine need to be attached integrally. In a structure in which the front cover and the rear cover are attached to the main body from both axial ends as in the above rotating electric machine, the number of divisions of the housing of the drive unit increases, which in turn increases the weight of the drive unit.

[0005] In view of the above circumstances, one object of the present invention is to reduce the weight of a drive device. [Means for solving the problem]

[0006] One embodiment of the drive device of the present invention includes a motor having a rotor rotatable about a central axis and a stator covering the radial outside of the rotor, a transmission mechanism connected to the motor, a motor housing that houses the motor therein, and a housing having a transmission mechanism housing that is fixed to one axial side of the motor housing and houses the transmission mechanism therein. The motor housing has a first housing member fixed to the transmission mechanism housing and a second housing member fixed to the other axial side of the first housing member with a plurality of bolts. The transmission mechanism housing has a third housing member fixed to the first housing member with a plurality of bolts, and a fourth housing member fixed to the one axial side of the third housing member with a plurality of bolts. The plurality of bolts that fix the first housing member and the second housing member are passed through a plurality of through holes provided in the second housing member from the other axial side, respectively, and fixed to a plurality of bolt holes provided in the first housing member. The 1 The bolts for fixing the housing member and the third housing member are passed through a plurality of through holes provided in the first housing member from the other axial side and fixed to a plurality of bolt holes provided in the third housing member. The bolts for fixing the third housing member and the fourth housing member are passed through a plurality of through holes provided in the fourth housing member from one axial side and fixed to a plurality of bolt holes provided in the third housing member. Effect of the Invention

[0007] According to one aspect of the present invention, the weight of the drive unit can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a drive device according to a first embodiment, seen from above. [Diagram 2] FIG. 2 is a cross-sectional view of the drive device of the first embodiment as seen from the rear side. [Diagram 3] FIG. 3 is a perspective view showing a part of a first housing member of the motor housing of the first embodiment. [Figure 4] FIG. 4 is a perspective view showing a part of a second housing member of the motor housing of the first embodiment. [Diagram 5] FIG. 5 is a cross-sectional perspective view showing a part of the oil supply passage of the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a part of the housing of the first embodiment. [Figure 7] FIG. 7 is a perspective view showing a part of the housing of the first embodiment. [Figure 8] FIG. 8 is a view of the first housing member of the motor housing according to the first embodiment, as viewed from the other axial side. [Figure 9] FIG. 9 is a perspective view showing the positioning portion of the first embodiment. [Figure 10] FIG. 10 is a perspective view showing the first trough portion of the first embodiment. [Figure 11] FIG. 11 is a view of the second groove portion of the first embodiment as viewed from one axial side. [Figure 12] FIG. 12 is a cross-sectional perspective view showing a part of the motor housing of the first embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing a part of the first flow path of the first embodiment. [Figure 14] FIG. 14 is a perspective view showing a part of a housing of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the following description, the vertical direction is defined based on the positional relationship when the drive device of the embodiment is mounted on a vehicle positioned on a horizontal road surface. In other words, the relative positional relationship in the vertical direction described in the following embodiment only needs to be satisfied when the drive device is mounted on a vehicle positioned on a horizontal road surface.

[0010] In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction is simply called the "upper side", and the lower side in the vertical direction is simply called the "lower side". The X axis direction is a direction perpendicular to the Z axis direction and is the front-rear direction of the vehicle on which the drive device 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 perpendicular to both the X axis direction and the Z axis direction, and is the left-right direction of the vehicle, that is, the vehicle width direction. 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-rear direction and the left-right direction are horizontal directions perpendicular to the vertical direction.

[0011] The positional relationship in the front-rear direction is not limited to that in the following embodiment, 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. In this specification, the "parallel direction" includes a substantially parallel direction, and the "orthogonal direction" includes a substantially orthogonal direction.

[0012] The central axis J1 shown in the drawings as appropriate 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 is simply referred to as the "axial direction", the radial direction centered on the central axis J1 is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J1, that is, around the axis of the central axis J1, is simply referred to as the "circumferential direction". In each of the following embodiments, the left side (+Y side) is referred to as the "one axial side", and the right side (-Y side) is referred to as the "other axial side".

[0013] An arrow θ shown in the drawings indicates the circumferential direction. In the following description, the side in the circumferential direction that progresses counterclockwise around the central axis J1 as viewed from one axial side (+Y side), i.e., the side to which the arrow θ points (+θ side), is referred to as the "one circumferential side," and the side in the circumferential direction that progresses clockwise around the central axis J1 as viewed from one axial side, i.e., the opposite side to the side to which the arrow θ points (-θ side), is referred to as the "other circumferential side."

[0014] First Embodiment The driving device 100 of the present embodiment shown in FIG. 1 and FIG. 2 is a driving device mounted on a vehicle and rotates an axle 64. The vehicle on which the driving device 100 is mounted is a vehicle that uses 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). As shown in FIG. 1 and FIG. 2, the driving device 100 includes a motor 20, a transmission mechanism 60, a housing 10 having a motor housing 11 that houses the motor 20 therein and a transmission mechanism housing 12 that houses the transmission mechanism 60 therein, bearings 71 to 76, an inverter unit 80, and a pump 94. The motor housing 11 and the transmission mechanism housing 12 are separate bodies that are fixed to each other. The transmission mechanism housing 12 is fixed to one axial side of the motor housing 11. That is, the transmission mechanism housing 12 is connected to one axial side of the motor housing 11. The bearings 71 to 76 are, for example, ball bearings.

[0015] The motor 20 is a part that drives the drive device 100. The motor 20 has a rotor 30 that can rotate around a central axis J1 that extends in the axial direction, and a stator 40. The rotor 30 has a shaft 31 and a rotor body 32. The shaft 31 can rotate around the central axis J1. The shaft 31 is rotatably supported by bearings 71, 72, 73, and 74. As a result, the bearings 71, 72, 73, and 74 rotatably support the rotor 30.

[0016] In this embodiment, the shaft 31 is a hollow shaft. The shaft 31 is cylindrical and extends in the axial direction about the central axis J1. The shaft 31 is provided with a hole 33 that connects the inside of the shaft 31 to the outside of the shaft 31. The shaft 31 extends across the inside of the motor housing 11 and the inside of the transmission mechanism housing 12. One axial end of the shaft 31 protrudes into the inside of the transmission mechanism housing 12. A reduction gear 61 is connected to one axial end of the shaft 31.

[0017] In this embodiment, the shaft 31 is configured by connecting a first shaft member 31a and a second shaft member 31b in the axial direction. The first shaft member 31a is accommodated inside the motor housing 11. The first shaft member 31a is provided with a hole 33. The second shaft member 31b is connected to one side of the first shaft member 31a in the axial direction. The outer diameter of the second shaft member 31b is smaller than the outer diameter of the first shaft member 31a. The other end of the second shaft member 31b in the axial direction is fitted into the inside of the one end of the first shaft member 31a in the axial direction. The second shaft member 31b extends from the inside of the motor housing 11 to the inside of the transmission mechanism housing 12. The first shaft member 31a and the second shaft member 31b are connected to each other by, for example, spline fitting. The first shaft member 31a is rotatably supported by bearings 71 and 72. The second shaft member 31b is rotatably supported by bearings 73 and 74.

[0018] The rotor body 32 is fixed to the outer circumferential surface of the shaft 31. More specifically, the rotor body 32 is fixed to the outer circumferential surface of the first shaft member 31a. Although not shown in the figure, the rotor body 32 has a rotor core and a rotor magnet fixed to the rotor core.

[0019] The stator 40 is located radially outside the rotor 30. The stator 40 is fixed inside the motor housing 11. The stator 40 has a stator core 41 and a coil assembly 42. The stator core 41 is annular and surrounds the rotor 30. The coil assembly 42 has a plurality of coils 42c attached to the stator core 41 along the circumferential direction. The plurality of coils 42c are attached to the stator core 41 via an insulator (not shown). Although not shown, the coil assembly 42 may have a bundling member or the like bundling the coils 42c, or may have a crossover wire connecting the coils 42c to each other. The coil assembly 42 has a coil end 42a protruding from the stator core 41 to one side in the axial direction, and a coil end 42b protruding from the stator core 41 to the other side in the axial direction.

[0020] The transmission mechanism 60 is connected to the motor 20. The transmission mechanism 60 transmits the rotation of the rotor 30 to an axle 64 of the vehicle. As shown in Fig. 1, the transmission mechanism 60 of this embodiment has a reduction gear 61 connected to the motor 20, and a differential gear 62 connected to the reduction gear 61.

[0021] The reduction gear 61 has a first gear 61a, a second gear 61b, a third gear 61c, and a gear shaft 61d. The first gear 61a is fixed to a portion of the shaft 31 that is located inside the transmission mechanism housing 12. The second gear 61b and the third gear 61c are fixed to the gear shaft 61d. The second gear 61b meshes with the first gear 61a. The gear shaft 61d extends in the axial direction about a gear axis J2 that extends parallel to the central axis J1. The gear axis J2 is a virtual axis that is located below the central axis J1. The gear axis J2 is located, for example, on the rear side (-X side) of the central axis J1. The gear shaft 61d is rotatably supported by bearings 75 and 76.

[0022] The differential device 62 has a ring gear 62a. The ring gear 62a meshes with the third gear 61c. A lower end of the ring gear 62a is immersed in the oil O stored in the transmission mechanism housing 12. When the ring gear 62a rotates, the oil O is scooped up. The scooped up oil O is supplied to, for example, the reduction gear 61 and the differential device 62 as lubricating oil. The differential device 62 rotates the axle 64 around a differential axis J3. The differential axis J3 is an imaginary axis extending parallel to the central axis J1.

[0023] The motor housing 11 accommodates therein the rotor 30 and the stator 40. The motor housing 11 has a first housing member 13 and a second housing member .

[0024] The first housing member 13 is a cylindrical member surrounding the motor 20 on the radial outside of the motor 20. In this embodiment, the inner peripheral surface of the first housing member 13 is cylindrical with the central axis J1 as the center. The first housing member 13 opens to the other axial side. The first housing member 13 is fixed to the transmission mechanism housing 12. The stator core 41 is fitted inside the first housing member 13. The first housing member 13 has a first opposing wall portion 13a that expands in the radial direction, a peripheral wall portion 13b that extends from the radial outer peripheral edge portion of the first opposing wall portion 13a to the other axial side, and a bearing holding portion 13c provided on the first opposing wall portion 13a.

[0025] The first opposing wall portion 13a faces the transmission mechanism housing 12 in the axial direction. The first opposing wall portion 13a is located on the other axial side of the transmission mechanism housing 12. The first opposing wall portion 13a is fixed to the transmission mechanism housing 12. The first opposing wall portion 13a has a hole 13d that penetrates the first opposing wall portion 13a in the axial direction. The hole 13d is a circular hole centered on the central axis J1. The second shaft member 31b is passed through the hole 13d in the axial direction.

[0026] As shown in Fig. 2, the first opposing wall portion 13a has a through hole 13e penetrating the first opposing wall portion 13a in the axial direction. The through hole 13e is a through hole that connects a space S located axially between the first opposing wall portion 13a and a second opposing wall portion 15a (described later) to the inside of the motor housing 11. The through hole 13e is provided in a portion of the first opposing wall portion 13a that is located below the bearing holding portion 13c. A lower end of the through hole 13e is connected to the inner circumferential surface of the peripheral wall portion 13b.

[0027] In this embodiment, the bearing holding portion 13c is provided on the surface of the first opposing wall portion 13a on the other axial direction side. The bearing holding portion 13c protrudes from the surface of the first opposing wall portion 13a on the other axial direction side to the other axial direction side. As shown in FIG. 3, the bearing holding portion 13c is cylindrical with the center on the central axis J1. The bearing holding portion 13c has a through portion 13f that penetrates the bearing holding portion 13c in the radial direction. In this embodiment, the through portion 13f penetrates a portion of the bearing holding portion 13c that is above the central axis J1 and located on the rear side (-X side) in the radial direction. The through portion 13f extends from the inner peripheral surface of the bearing holding portion 13c to the outer peripheral surface of the bearing holding portion 13c, rearward and obliquely upward. As shown in FIG. 1, the bearing holding portion 13c holds the bearing 72 therein.

[0028] The second housing member 14 is separate from the first housing member 13. The second housing member 14 is fixed to the other axial side of the first housing member 13. The second housing member 14 closes the opening on the other axial side of the first housing member 13. As shown in FIG. 4, the second housing member 14 has a cover wall portion 14a that spreads in the radial direction and a peripheral wall portion 14b that extends from the radial outer peripheral edge portion of the cover wall portion 14a to one axial side. As shown in FIG. 1, the end portion on one axial side of the peripheral wall portion 14b contacts the end portion on the other axial side of the peripheral wall portion 13b of the first housing member 13. The cover wall portion 14a has a recessed portion 14c that is recessed from the surface on one axial side of the cover wall portion 14a to the other axial side. The portion on one axial side of the recessed portion 14c is a bearing holding portion 14d that holds the bearing 71 therein.

[0029] In this embodiment, an inverter unit 80 is attached to the motor housing 11. The inverter unit 80 is fixed to the rear surface of the motor housing 11. Although not shown in the figure, the inverter unit 80 has an inverter circuit electrically connected to the stator 40.

[0030] The transmission mechanism housing 12 accommodates the reduction gear 61 and the differential gear 62 therein. As shown in Fig. 2, the transmission mechanism housing 12 protrudes downward further than the motor housing 11. A bottom surface located on the lower side of the inner surface of the transmission mechanism housing 12 is located lower than a bottom surface located on the lower side of the inner surface of the motor housing 11. The transmission mechanism housing 12 has a third housing member 15 fixed to the first housing member 13, and a fourth housing member 16 fixed to one axial side of the third housing member 15.

[0031] The third housing member 15 has a second opposing wall portion 15a extending in the radial direction, a peripheral wall portion 15b extending from the radial outer peripheral edge portion of the second opposing wall portion 15a to one axial side, and bearing holding portions 15c, 15d provided on the second opposing wall portion 15a. The second opposing wall portion 15a faces the first opposing wall portion 13a in the axial direction. The second opposing wall portion 15a is fixed to one axial side of the first opposing wall portion 13a. The second opposing wall portion 15a has a hole 15f penetrating the second opposing wall portion 15a in the axial direction. The hole 15f is a circular hole centered on the central axis J1. The second shaft member 31b is passed through the hole 15f in the axial direction.

[0032] The second opposing wall portion 15a has a recess 15e recessed from the surface of the second opposing wall portion 15a on the other axial side toward one axial side. The inner peripheral edge of the recess 15e is, for example, circular about the central axis J1 when viewed in the axial direction. The opening of the recess 15e on the other axial side is closed by the first opposing wall portion 13a. A space S is provided between the first opposing wall portion 13a and the second opposing wall portion 15a in the axial direction. The space S is formed by the inside of the recess 15e.

[0033] As shown in FIG. 2, the second opposing wall portion 15a has a through hole 15h penetrating the second opposing wall portion 15a in the axial direction. The through hole 15h is a through hole that connects a space S located between the first opposing wall portion 13a and the second opposing wall portion 15a in the axial direction and the inside of the transmission mechanism housing 12. The through hole 15h is provided in a portion of the second opposing wall portion 15a that is located lower than the bearing holding portion 15c. The through hole 15h is provided at a lower end of the bottom surface of the recessed portion 15e. The bottom surface of the recessed portion 15e is a surface that is located on one axial side of the inner surface of the recessed portion 15e and faces the other axial side. The lower end of the through hole 15h is connected to the inner peripheral surface of the recessed portion 15e. The through hole 15h is, for example, arranged opposite to one axial side of the through hole 13e provided in the first opposing wall portion 13a with a gap therebetween.

[0034] In this embodiment, the first opposing wall portion 13a and the second opposing wall portion 15a form a partition portion 19 that separates the interior of the motor housing 11 from the interior of the transmission mechanism housing 12. That is, the housing 10 has the partition portion 19. The partition portion 19 has a through hole 19a that connects the interior of the motor housing 11 to the interior of the transmission mechanism housing 12. The through hole 19a penetrates the partition portion 19 in the axial direction. In this embodiment, the through hole 19a is formed by a through hole 13e provided in the first opposing wall portion 13a, a lower end of the recess 15e, and a through hole 15h provided in the second opposing wall portion 15a.

[0035] In this embodiment, the bearing holders 15c and 15d are provided on a surface on one axial side of the second opposing wall portion 15a. The bearing holders 15c and 15d protrude from the surface on one axial side of the second opposing wall portion 15a to one axial side. As shown in FIG. 5, the bearing holder 15c is cylindrical and centered on the central axis J1. The bearing holder 15d is cylindrical and centered on the gear axis J2. As shown in FIG. 1, the bearing holder 15c holds the bearing 73 therein. The bearing holder 15d holds the bearing 75 therein.

[0036] The fourth housing member 16 has a cover wall portion 16a extending in the radial direction, a peripheral wall portion 16b extending from the radial outer peripheral edge portion of the cover wall portion 16a to the other axial direction side, and bearing holding portions 16c and 16d provided on the cover wall portion 16a. An end portion on the other axial direction side of the peripheral wall portion 16b is in axial contact with an end portion on one axial direction side of the peripheral wall portion 15b of the third housing member 15.

[0037] In this embodiment, the bearing holders 16c, 16d are provided on the surface of the cover wall portion 16a on the other axial direction side. The bearing holders 16c, 16d protrude from the surface of the cover wall portion 16a on the other axial direction side toward the other axial direction side. Although not shown in the drawings, the bearing holder 16c is cylindrical and centered on the central axis J1. The bearing holder 16d is cylindrical and centered on the gear axis J2. The bearing holder 16c holds the bearing 74 therein. The bearing holder 16d holds the bearing 76 therein.

[0038] Oil O is accommodated inside the transmission mechanism housing 12. The oil O is stored in a lower region inside the transmission mechanism housing 12. The oil O is used as a refrigerant that cools the motor 20. The oil O is also used as a lubricant for the reduction gear 61 and the differential gear 62. As the oil O, for example, it is preferable to use an oil equivalent to an automatic transmission lubricant (ATF: Automatic Transmission Fluid) having a relatively low viscosity in order to function as a refrigerant and a lubricant. In this embodiment, the oil O corresponds to the second fluid.

[0039] In this embodiment, a pump 94 is attached to the transmission mechanism housing 12. The pump 94 is attached to a lower surface of the transmission mechanism housing 12. The pump 94 is a pump that causes oil O to flow through a second supply flow path 92, which will be described later. In this embodiment, the pump 94 is an electric pump. Note that the pump 94 may be a mechanical pump that is rotated by the shaft 31 or the gear shaft 61d.

[0040] Although not shown, the axial gap between the first housing member 13 and the second housing member 14, the axial gap between the first housing member 13 and the third housing member 15, and the axial gap between the third housing member 15 and the fourth housing member 16 are sealed by seal members. The seal member is, for example, a liquid gasket.

[0041] In this embodiment, the first housing member 13, the second housing member 14, the third housing member 15, and the fourth housing member 16 are fixed to each other by bolts. More specifically, as shown in FIG. 6, the first housing member 13 and the second housing member 14 are fixed to each other by a first bolt 10a. The first housing member 13 and the third housing member 15 are fixed to each other by a second bolt 10b. The third housing member 15 and the fourth housing member 16 are fixed to each other by a third bolt 10c. The first bolt 10a, the second bolt 10b, and the third bolt 10c are each provided in a plurality of bolts surrounding the central axis J1. That is, the second housing member 14 is fixed to the other axial side of the first housing member 13 by a plurality of first bolts 10a. The third housing member 15 is fixed to one axial side of the first housing member 13 by a plurality of second bolts 10b. The fourth housing member 16 is fixed to one axial side of the third housing member 15 by a plurality of third bolts 10c.

[0042] The first bolts 10a respectively fix the first protrusions 13k provided on the outer peripheral surface of the first housing member 13 and the second protrusions 14k provided on the outer peripheral surface of the second housing member 14. The first protrusions 13k are provided on the other axial end of the outer peripheral surface of the first housing member 13. The first protrusions 13k protrude radially outward. As shown in FIG. 7 and FIG. 8, the first protrusions 13k are arranged at intervals along the circumferential direction. As shown in FIG. 8, in this embodiment, the first protrusions 13k are arranged at equal intervals around one circumference along the circumferential direction. In this embodiment, eight first protrusions 13k are provided.

[0043] In this specification, "certain objects are arranged at equal intervals" includes cases where certain objects are arranged at strictly equal intervals and cases where certain objects are arranged at approximately equal intervals.

[0044] The first protruding portion 13k has a female screw hole 13p recessed from the surface on the other axial side of the first protruding portion 13k to one axial side. In this embodiment, the female screw hole 13p penetrates the first protruding portion 13k in the axial direction. The female screw hole 13p may be a hole having a bottom on one axial side. One female screw hole 13p is provided for each first protruding portion 13k. That is, in this embodiment, a total of eight female screw holes 13p are provided. In this embodiment, the multiple female screw holes 13p are arranged at equal intervals around one circumference in the circumferential direction.

[0045] As shown in FIG. 7, the second protrusion 14k is provided at one axial end of the outer circumferential surface of the second housing member 14. The second protrusion 14k protrudes radially outward. The second protrusions 14k are arranged at intervals along the circumferential direction. Although not shown, the second protrusions 14k are arranged at equal intervals around the circumference. For example, eight second protrusions 14k are provided. The surface on one axial side of each second protrusion 14k contacts the surface on the other axial side of each first protrusion 13k.

[0046] The second protrusion 14k has a fixing hole 14p penetrating the second protrusion 14k in the axial direction. The fixing hole 14p is provided for each second protrusion 14k. For example, a total of eight fixing holes 14p are provided. The fixing holes 14p are arranged, for example, at equal intervals around one circumference along the circumferential direction. When viewed in the axial direction, each fixing hole 14p and each female screw hole 13p overlap each other. Each first bolt 10a is passed through each fixing hole 14p from the other axial side and fastened into each female screw hole 13p. As a result, the first housing member 13 and the second housing member 14 are fixed by the multiple first bolts 10a. As shown in FIG. 8, the multiple first bolts 10a are arranged at equal intervals around one circumference along the circumferential direction around the center axis J1.

[0047] As shown in FIG. 6 and FIG. 7, the second bolts 10b respectively fix the third protrusions 13m provided on the outer peripheral surface of the first housing member 13 and the fourth protrusions 15m provided on the outer peripheral surface of the third housing member 15. The third protrusions 13m are provided at one end of the outer peripheral surface of the first housing member 13 in the axial direction. The third protrusions 13m protrude radially outward. The third protrusions 13m are arranged at intervals along the circumferential direction. As shown in FIG. 8, in this embodiment, the third protrusions 13m are arranged at equal intervals around the circumference along the circumferential direction. In this embodiment, eight third protrusions 13m are provided. The circumferential position of the third protrusions 13m is shifted from the circumferential position of the first protrusions 13k. The circumferential position of the third protrusions 13m is, for example, the central position in the circumferential direction between the first protrusions 13k adjacent to each other in the circumferential direction. In this embodiment, the multiple first protrusions 13k and the multiple third protrusions 13m are arranged alternately with each other along the circumferential direction when viewed in the axial direction.

[0048] The third protrusion 13m has a fixing hole 13q penetrating the third protrusion 13m in the axial direction. One fixing hole 13q is provided for each third protrusion 13m. That is, in this embodiment, a total of eight fixing holes 13q are provided. The multiple fixing holes 13q are arranged at equal intervals around the circumference.

[0049] As shown in Figs. 6 and 7, the fourth protrusion 15m is provided at the end of the outer circumferential surface of the third housing member 15 on the other axial side. The fourth protrusion 15m protrudes radially outward. The multiple fourth protrusions 15m are arranged at intervals along the circumferential direction. Although not shown, the multiple fourth protrusions 15m are arranged at equal intervals around the circumference. For example, eight fourth protrusions 15m are provided. The surface on the other axial side of each fourth protrusion 15m contacts the surface on one axial side of each third protrusion 13m.

[0050] The fourth protrusion 15m has a female screw hole 15q recessed from the surface of the fourth protrusion 15m on the other axial side toward one axial side. In this embodiment, the female screw hole 15q penetrates the fourth protrusion 15m in the axial direction. The female screw hole 15q may be a hole having a bottom on one axial side. One female screw hole 15q is provided for each fourth protrusion 15m. For example, a total of eight female screw holes 15q are provided. The multiple female screw holes 15q are, for example, arranged at equal intervals around one circumference in the circumferential direction.

[0051] When viewed in the axial direction, the fixing holes 13q and the female screw holes 15q overlap each other. Each second bolt 10b is passed through each fixing hole 13q from the other axial side and screwed into each female screw hole 15q. As a result, the first housing member 13 and the third housing member 15 are fixed by the second bolts 10b. As shown in FIG. 8, the second bolts 10b are arranged at equal intervals around one circumference along the circumferential direction around the central axis J1. In this embodiment, the first bolts 10a and the second bolts 10b are arranged alternately around the circumferential direction around the central axis J1 when viewed in the axial direction. When viewed in the axial direction, each second bolt 10b is located at the center in the circumferential direction between the first bolts 10a adjacent to each other in the circumferential direction.

[0052] Thus, in this embodiment, the first housing member 13 and the third housing member 15 are fixed to each other by the second bolt 10b, which is fastened from the same side as the first bolt 10a that fixes the first housing member 13 and the second housing member 14. In other words, the second bolt 10b that fixes the first housing member 13 and the third housing member 15 is inserted into the fixing hole 13q and the female screw hole 15q in the same orientation as the first bolt 10a that fixes the first housing member 13 and the second housing member 14.

[0053] As shown in FIG. 6, the third bolt 10c fixes a fifth protrusion 15n provided at an end on one axial side of the outer peripheral surface of the third housing member 15 and a sixth protrusion 16n provided at an end on the other axial side of the outer peripheral surface of the fourth housing member 16. Although not shown, the fifth protrusion 15n and the sixth protrusion 16n are provided in plural numbers at intervals in the circumferential direction. The fifth protrusion 15n and the sixth protrusion 16n protrude radially outward. The circumferential positions of the fifth protrusion 15n and the sixth protrusion 16n may be the same as the circumferential positions of the third protrusion 13m and the fourth protrusion 15m, or may be shifted in the circumferential direction with respect to the third protrusion 13m and the fourth protrusion 15m.

[0054] The fifth protrusion 15n has a female screw hole 15r recessed from the surface of one axial side of the fifth protrusion 15n to the other axial side. In this embodiment, the female screw hole 15r penetrates the fifth protrusion 15n in the axial direction. The female screw hole 15r may be a hole having a bottom on the other axial side. The sixth protrusion 16n has a fixing hole 16r penetrating the sixth protrusion 16n in the axial direction. Each third bolt 10c is passed through each fixing hole 16r from one axial side and tightened into each female screw hole 15r. As a result, the third housing member 15 and the fourth housing member 16 are fixed by the multiple third bolts 10c.

[0055] In this manner, in this embodiment, the third housing member 15 and the fourth housing member 16 are fixed to each other by the first bolt 10a that fixes the first housing member 13 and the second housing member 14 and the third bolt 10c that is fastened from the side opposite to the side where the second bolt 10b that fixes the first housing member 13 and the third housing member 15 is fastened. In other words, the third bolt 10c that fixes the third housing member 15 and the fourth housing member 16 is inserted into the fixing hole 16r and the female screw hole 15r in a different orientation from the first bolt 10a that fixes the first housing member 13 and the second housing member 14 and the second bolt 10b that fixes the first housing member 13 and the third housing member 15.

[0056] In this embodiment, the female screw holes 13p, 13i, 15q, and 15r correspond to bolt holes, and the fixing holes 13q, 14e, 14p, and 16r correspond to through holes.

[0057] As described above, in this embodiment, the first housing member 13 and the third housing member 15 are fixed by the second bolt 10b from the same axial side as the side on which the first housing member 13 and the second housing member 14 are fixed by the first bolt 10a. Therefore, the operation of fixing the first housing member 13 and the second housing member 14 and the operation of fixing the first housing member 13 and the third housing member 15 can be performed from the same axial side, that is, from the other axial side in this embodiment. This improves the ease of assembly of the housing 10.

[0058] Here, in this embodiment, the transmission mechanism housing 12 has a shape that protrudes radially outward beyond the motor housing 11. In such a case, when attempting to fasten the first housing member 13 and the third housing member 15 by inserting a bolt from the side where the transmission mechanism housing 12 is located relative to the motor housing 11, i.e., from one axial side, it becomes necessary to position the fastening portion of the bolt further radially outward to avoid interference with the transmission mechanism housing 12 itself. This makes it easy for the housing 10 to become large.

[0059] In contrast, for example, if the first housing member 13, the third housing member 15, and the fourth housing member 16 are fastened together by a bolt inserted from one axial side, the first housing member 13 and the third housing member 15 can be fixed while preventing the housing 10 from becoming large. However, in this case, when the motor housing 11 and the transmission mechanism housing 12 are separated by removing the bolt, the third housing member 15 and the fourth housing member 16 constituting the transmission mechanism housing 12 are also separated. Therefore, the transmission mechanism housing 12 cannot be handled in an assembled state unless it is fixed to the motor housing 11. This tends to make the housing 10 difficult to assemble. In addition, the workability tends to be poor when performing maintenance on the drive unit 100 and when replacing the transmission mechanism 60.

[0060] In addition, the axial force of the bolt required to maintain a suitable seal may differ between the seal member provided between the first housing member 13 and the third housing member 15 in the axial direction and the seal member provided between the third housing member 15 and the fourth housing member 16 in the axial direction. Therefore, if the first housing member 13, the third housing member 15, and the fourth housing member 16 are fastened together with the same bolt, it may be difficult to apply a suitable axial force to the seal members provided between each of the housing members. This can easily cause problems such as a decrease in the seal between each of the housing members and difficulty in adjusting the axial force of the bolt.

[0061] The problems that arise when the first housing member 13, the third housing member 15, and the fourth housing member 16 described above are fastened together with a bolt inserted from one axial side are also present when the first housing member 13, the second housing member 14, and the third housing member 15 are fastened together with a bolt inserted from the other axial side.

[0062] In response to the above problem, according to the present embodiment, as described above, the first housing member 13 and the third housing member 15 are fixed by the second bolt 10b from the same side in the axial direction as the side where the first housing member 13 and the second housing member 14 are fixed by the first bolt 10a. Therefore, even if the position of the part fixed by the second bolt 10b is not changed to a position further outward in the radial direction, it is possible to prevent the second bolt 10b from interfering with the transmission mechanism housing 12. This allows the first housing member 13 and the third housing member 15 to be fixed by the second bolt 10b while preventing the housing 10 from becoming large. Furthermore, even if the second bolt 10b is removed, only the first housing member 13 and the third housing member 15 are separated, and the third housing member 15 and the fourth housing member 16 are not separated. Therefore, even if the transmission mechanism housing 12 is not fixed to the motor housing 11, it is possible to handle the transmission mechanism housing 12 in an assembled state. This prevents the housing 10 from being easily assembled. In addition, it is possible to prevent deterioration of workability when performing maintenance on the drive device 100 and when replacing the transmission mechanism 60. In addition, since the axial force can be changed between the second bolt 10b and the third bolt 10c, different axial forces can be applied to the seal member located between the first housing member 13 and the third housing member 15 and the seal member located between the third housing member 15 and the fourth housing member 16. This makes it easy to ensure the sealing between the housing members, and also makes it easy to adjust the axial force of the second bolt 10b and the axial force of the third bolt 10c. The same applies to the seal member between the first housing member 13 and the second housing member 14.

[0063] Also, for example, if another housing member is disposed between the motor housing 11 and the transmission mechanism housing 12 and the motor housing 11 and the transmission mechanism housing 12 are fixed to the other housing member, the motor housing 11 and the transmission mechanism housing 12 can be separated from each other in an assembled state. However, in this case, the number of parts constituting the housing 10 increases by the amount of the other housing member provided. In contrast, according to the present embodiment, as described above, the motor housing 11 and the transmission mechanism housing 12 can be separated from each other in an assembled state without providing the other member. Therefore, the increase in the number of parts constituting the housing 10 can be suppressed. In addition, since the other member is not required, the weight of the drive unit 100 can be reduced. As a result, even if the structure of the drive unit 100 is a water-cooled structure in which the motor 20 is cooled by water W as in the present embodiment, the increase in the weight of the entire drive unit 100 can be suppressed.

[0064] Furthermore, according to this embodiment, the multiple first bolts 10a that fix the first housing member 13 and the second housing member 14 fix the multiple first protrusions 13k provided on the outer circumferential surface of the first housing member 13 and the multiple second protrusions 14k provided on the outer circumferential surface of the second housing member 14. In this manner, by providing the first protrusions 13k and the second protrusions 14k that partially protrude from the outer circumferential surface of each housing member and fixing the first protrusions 13k and the second protrusions 14k with the first bolts 10a, it is possible to prevent the first housing member 13 and the second housing member 14 from becoming large in the radial direction over the entire circumference.

[0065] Furthermore, according to this embodiment, the multiple second bolts 10b that fix the first housing member 13 and the third housing member 15 fix the multiple third protrusions 13m provided on the outer circumferential surface of the first housing member 13 and the multiple fourth protrusions 15m provided on the outer circumferential surface of the third housing member 15. In this manner, by providing the third protrusions 13m and the fourth protrusions 15m that partially protrude from the outer circumferential surface of each housing member and fixing the third protrusions 13m and the fourth protrusions 15m with the second bolts 10b, it is possible to prevent the first housing member 13 and the third housing member 15 from becoming large in the radial direction over the entire circumference.

[0066] According to this embodiment, the first bolts 10a and the second bolts 10b are alternately arranged along the circumferential direction around the central axis J1 when viewed in the axial direction. Therefore, the first housing member 13, the second housing member 14, and the third housing member 15 are stably fixed by arranging the first bolts 10a and the second bolts 10b along the circumferential direction, respectively, and it is possible to prevent one of the first bolts 10a and the second bolts 10b from interfering with the other. This makes it easy to perform the work of fixing the first housing member 13 and the second housing member 14 with the first bolt 10a and the work of fixing the first housing member 13 and the third housing member 15 with the second bolt 10b when they are performed from the same axial side. Therefore, it is possible to improve the assemblability of the housing 10.

[0067] Furthermore, according to this embodiment, the multiple first bolts 10a are disposed at equal intervals around the circumference of the center axis J1. Therefore, the multiple first bolts 10a can more stably fasten the first housing member 13 and the second housing member 14 together. Also, the axial force applied by the multiple first bolts 10a to the seal member located between the first housing member 13 and the second housing member 14 can be made uniform over the entire circumference. This makes it easier to appropriately seal the gap between the first housing member 13 and the second housing member 14 over the entire circumference.

[0068] Moreover, according to this embodiment, the second bolts 10b are disposed at equal intervals around the circumference of the central axis J1. Therefore, the first housing member 13 and the third housing member 15 can be fixed more stably by the second bolts 10b. Also, the axial force applied by the second bolts 10b to the seal member located between the first housing member 13 and the third housing member 15 can be made uniform over the entire circumference. This makes it easy to suitably seal the gap between the first housing member 13 and the third housing member 15 over the entire circumference.

[0069] As shown by the two-dot chain line in FIG. 7, the third protrusion 13m provided on the first housing member 13 may extend in the axial direction. In this case, the end of the third protrusion 13m on the other axial side can be brought closer to the first protrusion 13k. This allows the position where the jig and tool for tightening the second bolt 10b is used when the work of fixing the first housing member 13 and the third housing member 15 is performed from the other axial side to be brought closer to the position where the jig and tool are used when the work of fixing the first housing member 13 and the second housing member 14 is performed. In addition, the axial dimensions of the jig and tool can be shortened. This improves the workability of the work of fixing the first housing member 13 and the third housing member 15 with the second bolt 10b. In particular, the second bolt 10b can be tightened appropriately to generate an axial force appropriately.

[0070] An end portion on the other axial direction side of the third protruding portion 13m shown by a two-dot chain line in Fig. 7 is, for example, located on the other axial direction side of the axial center of the first housing member 13. An end portion on the other axial direction side of the third protruding portion 13m shown by a two-dot chain line in Fig. 7 is, for example, located on one axial direction side of an end portion on one axial direction side of the first protruding portion 13k. This makes it possible to prevent the third protruding portion 13m from interfering with the first protruding portion 13k.

[0071] As shown in Figures 3 and 4, in this embodiment, the first housing member 13 and the second housing member 14 are also fixed by a fourth bolt 10d that is different from the above-mentioned multiple first bolts 10a. As shown in Figure 3, the first housing member 13 has a female screw hole 13i that is recessed axially from the end face on the other axial side of the peripheral wall portion 13b to one side. The female screw hole 13i is located circumferentially between a groove portion 93a (described later) and a second circumferential flow path portion 52b of the first flow path 50 (described later). The female screw hole 13i is located radially inside a recovery flow path main body portion 93c (described later).

[0072] As shown in FIG. 4, the second housing member 14 has a fixing hole 14e penetrating the second housing member 14 in the axial direction. The fixing hole 14e is located circumferentially between a connection portion 93b (described later) and a second circumferential flow path portion 52b of the first flow path 50 (described later). The fixing hole 14e is located radially inside a recovery flow path main body portion 93c (described later). A fourth bolt 10d passed through the fixing hole 14e from the other axial side is fastened to the female screw hole 13i. As a result, in this embodiment, the first housing member 13 and the second housing member 14 are fixed to each other radially inside a recovery flow path 93 (described later) and at a position adjacent to the first flow path 50 in the circumferential direction.

[0073] As shown in FIG. 9, the first housing member 13 has a positioning protrusion 13r provided on the outer circumferential surface of the first housing member 13. The second housing member 14 has a positioning protrusion 14r provided on the outer circumferential surface of the second housing member 14. The positioning protrusions 13r, 14r protrude radially outward. The positioning protrusion 13r has a hole 13s recessed from the surface on the other axial side of the positioning protrusion 13r to one axial side. The hole 13s is a circular hole having a bottom on one axial side. The positioning protrusion 14r has a hole 14s recessed from the surface on the one axial side of the positioning protrusion 14r to the other axial side. The hole 14s is a circular hole having a bottom on the other axial side. The hole 13s and the hole 14s face each other in the axial direction.

[0074] The positioning protrusion 13r is connected to one of the first protrusions 13k in the circumferential direction. The positioning protrusion 14r is connected to one of the second protrusions 14k in the circumferential direction. The positioning protrusion 13r and the positioning protrusion 14r are in contact with each other in the axial direction. As shown in FIG. 8, in this embodiment, two positioning protrusions 13r are provided at intervals in the circumferential direction. The two positioning protrusions 13r are provided at positions on almost opposite sides with the central axis J1 in between in the radial direction. Although not shown in the drawings, the positioning protrusions 14r are also provided at intervals in the circumferential direction, similar to the positioning protrusions 13r.

[0075] As shown in Fig. 9, in this embodiment, the housing 10 has a positioning pin 10e for positioning the first housing member 13 and the second housing member 14 in the circumferential direction. The positioning pin 10e is cylindrical and extends in the axial direction. The positioning pin 10e is fitted into both a hole 13s provided in a positioning protrusion 13r of the first housing member 13 and a hole 14s provided in a positioning protrusion 14r of the second housing member 14. This positions the first housing member 13 and the second housing member 14 in the circumferential direction.

[0076] An axially one portion of the positioning pin 10e is fitted into the hole portion 13s. An axially other portion of the positioning pin 10e is fitted into the hole portion 14s. As shown in Fig. 8, in this embodiment, two positioning pins 10e are provided. The two positioning pins 10e are provided at positions substantially opposite each other across the central axis J1.

[0077] In addition, in Fig. 1 and Fig. 2, the first protrusion 13k, the second protrusion 14k, the third protrusion 13m, the fourth protrusion 15m, the fifth protrusion 15n, the sixth protrusion 16n, and the positioning protrusions 13r, 14r are omitted. In Fig. 3, the first protrusion 13k and the positioning protrusion 13r are omitted. In Fig. 4, the second protrusion 14k and the positioning protrusion 14r are omitted. In Fig. 12, the first protrusion 13k, the second protrusion 14k, the third protrusion 13m, and the positioning protrusions 13r, 14r are omitted.

[0078] As shown in FIG. 2, the housing 10 has a first gutter portion 17. The first gutter portion 17 is located axially between the first opposing wall portion 13a and the second opposing wall portion 15a. That is, the first gutter portion 17 is located in the space S. As shown in FIG. 10, the first gutter portion 17 is gutter-shaped and opens upward and extends in the axial direction. Oil O flows inside the first gutter portion 17. The first gutter portion 17 is a reservoir capable of storing the oil O therein. In this embodiment, the first gutter portion 17 is located rearward (-X side) of the central axis J1. The first gutter portion 17 is located rearward of the hole 13d.

[0079] The first gutter 17 connects the first opposing wall 13a and the second opposing wall 15a. In this embodiment, the first gutter 17 has a first portion 17a that protrudes from a surface on one axial side (+Y side) of the first opposing wall 13a toward one axial side, and a second portion 17b that protrudes from a surface on the other axial side (-Y side) of the second opposing wall 15a toward the other axial side. The end of the first portion 17a on one axial side and the end of the second portion 17b on the other axial side are connected to each other. The axial dimension of the second portion 17b is larger than the axial dimension of the first portion 17a.

[0080] The first gutter portion 17 has a bottom surface 17c facing upward, and a pair of side surfaces 17d, 17e protruding upward from both sides of the bottom surface 17c in the front-rear direction. The bottom surface 17c and the pair of side surfaces 17d, 17e extend in the axial direction. The bottom surface 17c and the pair of side surfaces 17d, 17e connect the first opposing wall portion 13a and the second opposing wall portion 15a. The pair of side surfaces 17d, 17e are disposed opposite each other with a gap therebetween in the axial direction. The side surface 17d is located on the front side (+X side) of the side surface 17e.

[0081] The bottom surface 17c is inclined vertically with respect to the front-rear direction. The bottom surface 17c is located lower as it approaches the front side (+X side). In this embodiment, the bottom surface 17c is an inclined surface that is located lower as it approaches the first hole portion 13g provided in the first opposing wall portion 13a. Therefore, the oil O in the first gutter portion 17 is easily guided into the first hole portion 13g along the bottom surface 17c by utilizing gravity. The first hole portion 13g penetrates the first opposing wall portion 13a in the axial direction. The first hole portion 13g is, for example, a circular hole. The first hole portion 13g opens at the front end of the inside of the first gutter portion 17. The first hole portion 13g is connected to the bottom surface 17c and the side surface 17d.

[0082] As shown in Fig. 5, the first gutter portion 17 is connected to a portion of the surface of the first opposing wall portion 13a on one axial side thereof that is located below the first hole portion 13g and a portion of the surface of the second opposing wall portion 15a on the other axial side thereof that is located below the second hole portion 15g. The second hole portion 15g penetrates the second opposing wall portion 15a in the axial direction. The second hole portion 15g is, for example, a circular hole. The second hole portion 15g opens to an end portion on the rear side (-X side) of the inside of the first gutter portion 17 and an end portion on the front side (+X side) of the inside of the second gutter portion 18.

[0083] As shown in FIG. 2, the housing 10 has a second gutter portion 18. The second gutter portion 18 is located inside the transmission mechanism housing 12. As shown in FIG. 5 and FIG. 11, the second gutter portion 18 is gutter-shaped and opens upward and extends in the axial direction. Oil O flows inside the second gutter portion 18. The second gutter portion 18 is a reservoir capable of storing the oil O inside. In this embodiment, the second gutter portion 18 is located rearward (-X side) of the central axis J1. The second gutter portion 18 is located above the bearing holding portion 15d. As shown in FIG. 5, the front end (+X side) of the second gutter portion 18 is located on one axial side (+Y side) of the rear end of the first gutter portion 17.

[0084] 2, the second gutter portion 18 connects the second opposing wall portion 15a and the cover wall portion 16a. In this embodiment, the second gutter portion 18 has a first portion 18a that protrudes to one axial direction side from a surface on one axial direction side (+Y side) of the second opposing wall portion 15a, and a second portion 18b that protrudes to the other axial direction side from a surface on the other axial direction side (-Y side) of the cover wall portion 16a. The end portion on one axial direction side of the first portion 18a and the end portion on the other axial direction side of the second portion 18b are connected to each other.

[0085] As shown in Fig. 11, the second gutter portion 18 has a bottom surface 18c facing upward, and a pair of side surfaces 18d, 18e protruding upward from both sides of the bottom surface 18c in the front-rear direction. The bottom surface 18c and the pair of side surfaces 18d, 18e extend in the axial direction. The bottom surface 18c and the pair of side surfaces 18d, 18e connect the second opposing wall portion 15a and the cover wall portion 16a. The pair of side surfaces 18d, 18e are disposed opposite each other with a gap therebetween in the axial direction.

[0086] The side surface 18d is located in front of the side surface 18e (+X side). The side surface 18d is inclined in the front-rear direction with respect to the vertical direction. The side surface 18d is located closer to the front (+X side) as it approaches the upper side. In this embodiment, the side surface 18d is an inclined surface that is located lower as it approaches the second hole portion 15g. Therefore, the oil O that has entered the second gutter portion 18 can be easily guided along the side surface 18d to the inside of the second hole portion 15g by utilizing gravity.

[0087] Side surface 18e is inclined in the front-rear direction with respect to the vertical direction. Side surface 18d is located toward the rear (-X side) as it moves upward. Bottom surface 18c is inclined in the vertical direction with respect to the front-rear direction. Bottom surface 18c is located toward the rear (-X side).

[0088] As shown in FIG. 5, the second gutter portion 18 is connected to a portion of the surface on one axial side of the second opposing wall portion 15a that is located below the second hole portion 15g. The second gutter portion 18 is provided with supply holes 18f, 18g. The supply hole portion 18f connects the inside of the second gutter portion 18 to the inside of the bearing holding portion 15c. Therefore, a portion of the oil O that has entered the second gutter portion 18 is supplied to the bearing 73 in the bearing holding portion 15c through the supply hole portion 18f. As shown in FIG. 11, the supply hole portion 18f opens to the side surface 18d. The supply hole portion 18f extends from the side surface 18d toward the front side (+X side) and diagonally downward.

[0089] Supply hole 18g connects the inside of second gutter 18 to the inside of bearing holder 15d. Therefore, a portion of oil O that enters second gutter 18 is supplied to bearing 75 in bearing holder 15d through supply hole 18g. Supply hole 18g opens to bottom surface 18c. Supply hole 18g extends downward and diagonally forward (+X side) from bottom surface 18c.

[0090] As shown in FIG. 2, the housing 10 has a first flow path 50 and a second flow path 90. The first flow path 50 is a flow path through which water W flows as a first fluid. The second flow path 90 is a flow path through which oil O flows as a second fluid. In this embodiment, the oil O and the water W function as a refrigerant that cools the stator 40. That is, in this embodiment, the first flow path 50 and the second flow path 90 are flow paths through which water W flows as a refrigerant that cools the stator 40. In this embodiment, at least a part of the first flow path 50 and at least a part of the second flow path 90 are configured by the first housing member 13, the second housing member 14, and the third housing member 15. Therefore, it is easy to increase the axial range in which the first flow path 50 and the second flow path 90 are provided, and it is easy to cool the stator 40.

[0091] In this specification, the term "flow path" refers to a path through which a fluid flows. Therefore, the term "flow path" is a concept that includes not only a "flow path" that creates a steady flow of fluid in one direction, but also a path that temporarily retains a fluid and a path through which a fluid drips. A path that temporarily retains a fluid includes, for example, a reservoir that stores a fluid.

[0092] At least a portion of the second flow passage 90 is defined by the first housing member 13 and the third housing member 15. In this embodiment, the second flow passage 90 is defined by the first housing member 13, the second housing member 14, and the third housing member 15. The second flow passage 90 has a first supply flow passage 91, a second supply flow passage 92, and a recovery flow passage 93. The first supply flow passage 91 and the second supply flow passage 92 are supply flow passages that supply the oil O in the transmission mechanism housing 12 to the inside of the motor housing 11.

[0093] The first supply flow passage 91 has a scooping path 91a, a shaft supply path 91b, a shaft internal path 91c, and a rotor internal path 90a. The scooping path 91a is a path through which the oil O in the transmission mechanism housing 12 is scooped up by the rotation of the ring gear 62a of the differential device 62 and enters the second gutter portion 18. The shaft supply path 91b is a path through which the oil O in the second gutter portion 18 flows into the bearing holding portion 16c through a flow path (not shown) provided in the cover wall portion 16a, and flows from the bearing holding portion 16c into the shaft 31. The oil O flows into the bearing holding portion 16c in the shaft supply path 91b, so that the oil O is supplied to the bearing 74 held by the bearing holding portion 16c. In the shaft supply path 91b of this embodiment, the oil O flows in from one axial end of the shaft 31.

[0094] The intra-shaft path 91c is a path along which the oil O that has flowed into the shaft 31 from one axial end of the shaft 31 flows through the shaft 31 to the other axial end. The intra-rotor path 90a is a path along which the oil O in the shaft 31 passes from the hole 33 through the inside of the rotor body 32 and splashes onto the stator 40. In this manner, the oil O is supplied to the rotor 30 and the stator 40 by the first supply flow path 91.

[0095] 1, the second supply passage 92 has an introduction passage portion 92a, a connecting passage portion 92b, a shaft internal passage 92c, and a rotor internal passage 90a. The introduction passage portion 92a extends in the axial direction from the inside of the transmission mechanism housing 12. More specifically, the introduction passage portion 92a extends from the inside of the transmission mechanism housing 12 to the other axial direction side, passes through the second opposing wall portion 15a, the first opposing wall portion 13a, and the peripheral wall portion 13b, and extends to the second housing member 14. That is, the introduction passage portion 92a has a passage portion 92d provided in the first housing member 13, a passage portion 92e provided in the second housing member 14, and a passage portion 92f provided in the third housing member 15.

[0096] In this embodiment, the flow path portion 92d corresponds to the "first portion", and the flow path portion 92f corresponds to the "third portion". That is, in this embodiment, the second flow path 90 has the flow path portion 92d as the first portion and the flow path portion 92f as the second portion. The flow path portion 92f as the second portion is connected to one axial side of the flow path portion 92d as the first portion. Therefore, the second flow path 90 can be suitably enlarged in the axial direction by the flow path portion 92d and the flow path portion 92f. The flow path portion 92e is connected to the other axial side of the flow path portion 92d. Therefore, the second flow path 90 can be suitably enlarged in the axial direction by the flow path portion 92d and the flow path portion 92e. The flow path portion 92f as the second portion penetrates the second opposing wall portion 15a in the axial direction and opens to the inside of the transmission mechanism housing 12. Therefore, the oil O in the transmission mechanism housing 12 can be flowed from the flow path portion 92f into the introduction flow path portion 92a. The oil O sucked from the inside of the transmission mechanism housing 12 by the pump 94 flows into the introduction flow passage portion 92a. In the introduction flow passage portion 92a, the oil O flows to the other axial side.

[0097] As shown in Fig. 3, the cross section of the introduction flow passage portion 92a is an ellipse that is long in the circumferential direction. The circumferential dimension of the introduction flow passage portion 92a is smaller than the circumferential dimension of the recovery flow passage main body portion 93c described later, the circumferential dimension of the first circumferential flow passage portion 52a described later, and the circumferential dimension of the second circumferential flow passage portion 52b described later. Therefore, the circumferential dimension of the introduction flow passage portion 92a can be made relatively small. This can reduce the pressure loss caused in the oil O flowing in the introduction flow passage portion 92a. Therefore, the oil O can be easily sent into the introduction flow passage portion 92a by the pump 94.

[0098] The introduction flow passage portion 92a is located, for example, in front of (on the +X side) and below the central axis J1. At least a portion of the introduction flow passage portion 92a is located radially outside the first flow passage 50. In this embodiment, almost the entire introduction flow passage portion 92a, except for both axial ends, is located radially outside the first flow passage 50. The introduction flow passage portion 92a is located below the first flow passage 50.

[0099] As shown in FIG. 1, the connecting flow passage portion 92b is provided in the cover wall portion 14a of the second housing member 14. The connecting flow passage portion 92b extends upward from the end portion on the other axial side of the introduction flow passage portion 92a and connects to the recessed portion 14c. As a result, the oil O flows into the recessed portion 14c. A part of the oil O that flows into the recessed portion 14c is supplied to the bearing 71 held by the bearing holding portion 14d. The other part of the oil O that flows into the recessed portion 14c flows into the shaft 31 from the other axial side. The shaft internal path 92c is a path through which the oil O that flows into the shaft 31 from the end portion on the other axial side of the shaft 31 flows inside the shaft 31 to one axial side. Thus, in this embodiment, the oil O flows into the shaft 31 from both sides in the axial direction by the first supply flow passage 91 and the second supply flow passage 92. Therefore, for example, compared to the case where the oil O flows into the shaft 31 only from one end portion, the oil O can be suitably flowed throughout the entire axial direction of the shaft 31. That is, it is possible to prevent the oil O that flows in from one end of the shaft 31 from reaching the other end of the shaft 31 and not reaching the entire inside of the shaft 31. Therefore, it is easy to suitably supply the oil O to each of the bearings 71, 74 that support both axial ends of the shaft 31. The oil O that flows through the in-shaft path 92c flows through the in-rotor path 90a, similarly to the in-shaft path 91c, and is supplied to the rotor 30 and the stator 40.

[0100] The oil O supplied to the stator 40 by the first supply passage 91 and the second supply passage 92 removes heat from the stator 40. After cooling the stator 40, the oil O drops downward and accumulates in a lower region within the motor housing 11. The oil O that has accumulated in the lower region within the motor housing 11 returns to the inside of the transmission mechanism housing 12 via the through hole 19a of the partition portion 19 or the recovery passage 93.

[0101] As shown in FIG. 2, the recovery passage 93 extends from the inside of the motor housing 11 to the inside of the transmission mechanism housing 12. In this embodiment, the recovery passage 93 is provided across the third housing member 15, the first housing member 13, and the second housing member 14. The recovery passage 93 is located below the motor 20. The recovery passage 93 has a groove 93a, a connection portion 93b, and a recovery passage main body portion 93c. The groove 93a is provided on the inner circumferential surface of the motor housing 11. In this embodiment, the groove 93a is recessed downward from a portion located on the lower side of the inner circumferential surface of the first housing member 13. The groove 93a extends in the axial direction. An end portion on one axial side of the groove 93a is closed. An end portion on the other axial side of the groove 93a opens into an end face on the other axial side of the peripheral wall portion 13b. An end portion on the other axial side of the groove 93a is connected to the connection portion 93b.

[0102] The bottom surface of the groove portion 93a is located lower toward the other axial side. In other words, the bottom surface of the groove portion 93a is an inclined surface located lower toward the connecting portion 93b. Therefore, the oil O that has entered the groove portion 93a can be easily guided to the connecting portion 93b along the bottom surface of the groove portion 93a by utilizing gravity. The bottom surface of the groove portion 93a is a surface of the inner surface of the groove portion 93a that is located radially outward and faces radially inward. In this embodiment, the bottom surface of the groove portion 93a faces upward. As shown in FIG. 12, the circumferential dimension of the groove portion 93a is smaller than the circumferential dimension of the through hole 13e.

[0103] The connection portion 93b connects the groove portion 93a and the recovery flow passage main body portion 93c. The connection portion 93b is connected to the end portion 93f of the groove portion 93a on the other axial side. In this embodiment, the connection portion 93b is provided on the peripheral wall portion 14b of the second housing member 14. The connection portion 93b extends downward from a portion located on the lower side of the inner peripheral surface of the peripheral wall portion 14b. The connection portion 93b opens upward. As shown in FIG. 2, the lower end portion of the connection portion 93b is connected to the end portion 93g of the recovery flow passage main body portion 93c on the other axial side. As a result, the connection portion 93b connects the end portion 93f of the groove portion 93a on the other axial side and the end portion 93g of the recovery flow passage main body portion 93c on the other axial side.

[0104] The recovery flow passage body 93c is located radially outward of the groove 93a. In this embodiment, the recovery flow passage body 93c is located below the groove 93a. The recovery flow passage body 93c extends in the axial direction and is connected to the inside of the transmission mechanism housing 12. An end 93p on one axial side of the recovery flow passage body 93c opens into the inside of the transmission mechanism housing 12. In this embodiment, the recovery flow passage body 93c is provided across the second housing member 14, the first housing member 13, and the third housing member 15. That is, the recovery flow passage body 93c has a flow passage portion 93h provided in the first housing member 13, a flow passage portion 93i provided in the second housing member 14, and a flow passage portion 93j provided in the third housing member 15. An end 93k on one axial side of the flow passage portion 93h is connected to an end on the other axial side of the flow passage portion 93j. An end 93m on the other axial side of the flow path portion 93h is connected to an end on one axial side of the flow path portion 93i. The recovery flow path main body 93c extends to one axial side from the lower end of the connection portion 93b, axially penetrating the first housing member 13 and the third housing member 15, and opening into the inside of the transmission mechanism housing 12. The recovery flow path main body 93c is located below the through hole 19a of the partition portion 19.

[0105] In this embodiment, the flow path portion 93h corresponds to the "first portion", and the flow path portion 93j corresponds to the "second portion". That is, in this embodiment, the second flow path 90 has the flow path portion 93h as the first portion, and the flow path portion 93j as the second portion connected to one axial side of the first portion. Therefore, the second flow path 90 can be suitably enlarged in the axial direction by the flow path portion 93h and the flow path portion 93j. The flow path portion 93j as the second portion penetrates the second opposing wall portion 15a in the axial direction and opens to the inside of the transmission mechanism housing 12. Therefore, the oil O can be returned from the flow path portion 93j to the inside of the transmission mechanism housing 12.

[0106] 3 and 4, the flow passage cross section of the recovery flow passage main body 93c has a shape that is long in the circumferential direction. The circumferential dimension of the recovery flow passage main body 93c is larger than the circumferential dimension of the groove portion 93a and the circumferential dimension of the connection portion 93b. Therefore, the flow rate of the oil O that can flow into the recovery flow passage main body 93c can be increased. This allows the amount of oil O that can be returned from inside the motor housing 11 to inside the transmission mechanism housing 12 to be increased.

[0107] At least a part of the recovery flow passage main body 93c is located radially outside the first flow passage 50. As a result, at least a part of the recovery flow passage 93 is located radially outside the first flow passage 50. As shown in FIG. 12, a part of the recovery flow passage main body 93c is located below a pair of axial flow passage sections 51 (described later) arranged circumferentially sandwiching the groove section 93a of the first flow passage 50, a first circumferential flow passage section 52c (described later) arranged on one axial side of the groove section 93a of the first flow passage 50, and a pair of second circumferential flow passage sections 52b (described later) arranged circumferentially sandwiching the connection section 93b of the first flow passage 50. In this embodiment, as described above, the circumferential dimension of the recovery flow passage main body 93c is larger than the circumferential dimension of the groove section 93a and the circumferential dimension of the connection section 93b, so that the recovery flow passage main body 93c can be protruded circumferentially beyond the groove section 93a and the connection section 93b. Therefore, the recovery flow passage main body 93c can be easily arranged radially outside the first flow passage 50.

[0108] The recovery flow passage main body 93c is disposed adjacent to one circumferential side (+θ side) of the introduction flow passage portion 92a. That is, in this embodiment, the introduction flow passage portion 92a is disposed adjacent to the recovery flow passage 93 in the circumferential direction. In this embodiment, the portion of the motor housing 11 in which the recovery flow passage main body 93c and the introduction flow passage portion 92a are provided protrudes downward further than other portions of the motor housing 11.

[0109] The recovery flow passage main body 93c is provided with a partition wall 93d that divides the inside of the recovery flow passage main body 93c in the circumferential direction. The partition wall 93d extends in the axial direction from an end 93p on one axial side of the flow passage portion 93h toward the other axial side. In this embodiment, the partition wall 93d extends from an end 93k on one axial side of the flow passage portion 93h to the axial center of the flow passage portion 93h. In other words, the partition wall 93d extends from an end on one axial side of the first housing member 13 to the axial center of the first housing member 13. The partition wall 93d divides the circumferentially long recovery flow passage main body 93c into approximately two equal parts in the circumferential direction. The partition wall 93d can improve the strength of the part of the housing 10 where the recovery flow passage main body 93c is provided. In addition, the axial force of the second bolt 10b can be more suitably transmitted to the first housing member 13 and the third housing member 15.

[0110] It should be noted that the partition wall portion 93d does not have to extend to the axial center of the flow path portion 93h, i.e., the axial center of the first housing member 13. For example, the end portion 93r on the other axial side of the partition wall portion 93d may be disposed in any position as long as it is located on the other axial side of the end portion 93k on one axial side of the flow path portion 93h and is located on one axial side of the end portion 93m on the other axial side of the flow path portion 93h.

[0111] 3, the recovery passageway main body 93c has a recess 93e recessed radially inward. The recess 93e is located in the circumferential center of the other axial side portion of the recovery passageway main body 93c. The outer peripheral surface of the portion of the motor housing 11 where the recess 93e is provided is recessed radially inward. This can prevent, for example, second bolt 10b that fastens the first housing member 13 and the third housing member 15 from interfering with the recovery passageway main body 93c.

[0112] As shown in Figs. 1 and 2, at least a part of the first flow passage 50 is located radially outside the motor 20. In this embodiment, almost the entire first flow passage 50, except for both axial ends, is located radially outside the motor 20. A lower portion of the first flow passage 50 is located radially between the recovery flow passage main body 93c and the motor 20. As shown in Figs. 12 and 13, in this embodiment, the first flow passage 50 extends in a rectangular wave shape along the circumferential direction. The first flow passage 50 has a plurality of axial flow passage portions 51, a plurality of first circumferential flow passage portions 52a, and a plurality of second circumferential flow passage portions 52b.

[0113] The multiple axial flow passage portions 51 extend in the axial direction. The multiple axial flow passage portions 51 are arranged at intervals in the circumferential direction. In this embodiment, the axial flow passage portions 51 are provided in the motor housing 11. More specifically, the axial flow passage portions 51 are provided in the first housing member 13. As shown in FIG. 12 , the two axial flow passage portions 51 located on the lower side among the multiple axial flow passage portions 51 are arranged to sandwich the groove portion 93a in the circumferential direction.

[0114] 1, the multiple axial flow passage sections 51 include an axial flow passage section 51c divided into two in the axial direction by a partition wall section 51d. The axial flow passage section 51c has an upstream side flow passage section 51a and a downstream side flow passage section 51b. In this embodiment, the upstream side flow passage section 51a is a portion of the axial flow passage section 51c located on one axial side of the partition wall section 51d. In this embodiment, the downstream side flow passage section 51b is a portion of the axial flow passage section 51c located on the other axial side of the partition wall section 51d.

[0115] 13, in this embodiment, the axial flow passage portion 51 is formed by at least a part of the hole 11a that axially penetrates the first housing member 13. The axial flow passage portion 51 is formed by, for example, a portion of the hole 11a excluding both axial ends. An opening on one axial side of the hole 11a is blocked by the third housing member 15. An opening on the other axial side of the hole 11a is blocked by the second housing member 14.

[0116] As shown in FIG. 12, the first circumferential flow passage section 52a and the second circumferential flow passage section 52b extend in the circumferential direction. The first circumferential flow passage sections 52a are arranged at intervals in the circumferential direction. The second circumferential flow passage sections 52b are arranged at intervals in the circumferential direction. The first circumferential flow passage section 52a connects the ends on one axial side of the axial flow passage sections 51 adjacent to each other in the circumferential direction. The second circumferential flow passage section 52b connects the ends on the other axial side of the axial flow passage sections 51 adjacent to each other in the circumferential direction. The first flow passage section 52a and the second circumferential flow passage section 52b alternately connect the ends on both axial sides of the axial flow passage sections 51, so that the first flow passage 50 has a rectangular wave shape.

[0117] The first circumferential flow passage sections 52a include a first circumferential flow passage section 52c that circumferentially spans one axial side of the groove section 93a. The first circumferential flow passage section 52c is the first circumferential flow passage section 52a that is located at the lowest position among the first circumferential flow passage sections 52a. The circumferential dimension of the first circumferential flow passage section 52c is larger than the circumferential dimensions of the other first circumferential flow passage sections 52a. A through hole 13e is located above the other circumferential side (-θ side) portion of the first circumferential flow passage section 52c.

[0118] The second circumferential flow passage portions 52b include a pair of second circumferential flow passage portions 52b that circumferentially sandwich the other axial end portion of the groove portion 93a and the connection portion 93b. That is, in this embodiment, the other axial end portion of the groove portion 93a and the connection portion 93b are located between the second circumferential flow passage portions 52b adjacent to each other in the circumferential direction.

[0119] As shown in FIG. 13, in this embodiment, the first circumferential flow passage portion 52a is provided across the motor housing 11 and the transmission mechanism housing 12. More specifically, the first circumferential flow passage portion 52a is provided across the first housing member 13 and the third housing member 15. That is, at least a part of the first circumferential flow passage portion 52a is provided in the third housing member 15. At least a part of the inner surface of the first circumferential flow passage portion 52a is the surface of the third housing member 15. The first circumferential flow passage portion 52a is configured by axially connecting a part provided on an end face on one axial side of the first housing member 13 and a groove recessed from an end face on the other axial side of the third housing member 15 to one axial side.

[0120] In this embodiment, the second circumferential flow passage portion 52b is provided across the first housing member 13 and the second housing member 14. That is, at least a part of the second circumferential flow passage portion 52b is provided in the second housing member 14. At least a part of the inner surface of the second circumferential flow passage portion 52b is the surface of the second housing member 14. In this embodiment, the first flow passage 50 is provided across the first housing member 13 and the second housing member 14. The second circumferential flow passage portion 52b is configured by axially connecting a part provided on an end face on the other axial direction side of the first housing member 13 and a groove recessed from an end face on one axial direction side of the second housing member 14 to the other axial direction side.

[0121] An end portion on one axial direction side of a partition wall portion 52d that circumferentially separates the pair of axial flow passage portions 51 connected by the first circumferential flow passage portion 52a is disposed away from the other axial direction side of an end face on one axial direction side of the first housing member 13. An end portion on the other axial direction side of a partition wall portion 52e that circumferentially separates the pair of axial flow passage portions 51 connected by the second circumferential flow passage portion 52b is disposed away from the other axial direction side of the end face on the other axial direction side of the first housing member 13.

[0122] In the axial flow passage section 51, the water W flows in the axial direction. The directions in which the water W flows in the axial flow passage sections 51 adjacent to each other in the circumferential direction are opposite to each other. In the first circumferential flow passage section 52a and the second circumferential flow passage section 52b, the water W flows toward one circumferential side (+θ direction). The first circumferential flow passage section 52a connects the end of one axial side of the axial flow passage section 51 where the water W flows toward one axial side and the end of one axial side of the axial flow passage section 51 where the water W flows toward the other axial side. The second circumferential flow passage section 52b connects the end of the other axial side of the axial flow passage section 51 where the water W flows toward the other axial side and the end of the other axial side of the axial flow passage section 51 where the water W flows toward one axial side.

[0123] As shown in FIG. 1, the first flow path 50 has an inflow flow path portion 53a and an outflow flow path portion 53b. In this embodiment, the inflow flow path portion 53a and the outflow flow path portion 53b pass through the inside of the inverter unit 80. Water W flows into the inflow flow path portion 53a from the outside of the drive device 100. The water W that flows into the inflow flow path portion 53a flows into the upstream side flow path portion 51a. The water W that flows into the upstream side flow path portion 51a flows around the motor 20 while flowing along a rectangular wave-shaped flow path formed by the axial flow path portion 51, the first circumferential flow path portion 52a, and the second circumferential flow path portion 52b, and flows into the outflow flow path portion 53b from the downstream side flow path portion 51b. The water W that flows into the outflow flow path portion 53b flows out to the outside of the drive device 100.

[0124] As shown in FIG. 6, the fastening surfaces 13x and 14x of the first housing member 13 and the second housing member 14 fixed to each other by the first bolt 10a are sealing surfaces that seal a part of the first flow passage 50 at the connection part between the first housing member 13 and the second housing member 14. The fastening surface 13x is a surface on the other axial side of the first housing member 13. The fastening surface 14x is a surface on one axial side of the second housing member 14. The fastening surfaces 13x and 14x are also sealing surfaces that seal a part of the second flow passage 90 at the connection part between the first housing member 13 and the second housing member 14. Therefore, a part of the first flow passage 50 and a part of the second flow passage 90 at the connection part between the first housing member 13 and the second housing member 14 can be sealed together by the first bolt 10a. This makes it easier to assemble the housing 10 compared to a case in which the first flow passage 50 and the second flow passage 90 are sealed by different bolts, respectively. In addition, the number of parts in the drive device 100 can be easily reduced.

[0125] The fastening surfaces 13y and 15y of the first housing member 13 and the third housing member 15 fixed to each other by the second bolt 10b are sealing surfaces that seal a part of the first flow passage 50 at the connection part between the first housing member 13 and the third housing member 15. The fastening surface 13y is a surface on one axial side of the first housing member 13. The fastening surface 15y is a surface on the other axial side of the third housing member 15. The fastening surfaces 13y and 15y are also sealing surfaces that seal a part of the second flow passage 90 at the connection part between the first housing member 13 and the third housing member 15. Therefore, a part of the first flow passage 50 and a part of the second flow passage 90 at the connection part between the first housing member 13 and the third housing member 15 can be sealed together by the second bolt 10b. This makes it easier to assemble the housing 10 compared to a case where the first flow passage 50 and the second flow passage 90 are sealed by different bolts, respectively. In addition, the number of parts in the drive device 100 can be reduced.

[0126] As shown in FIG. 2, the housing 10 has an oil supply passage 95. The oil supply passage 95 extends from the inside of the transmission mechanism housing 12 through the second opposing wall portion 15a in the axial direction. In this embodiment, the oil supply passage 95 extends through the first opposing wall portion 13a in the axial direction to the inside of the motor housing 11. As shown in FIG. 5, the oil supply passage 95 has a supply port 13h that supplies oil O to the bearing 72 held by the bearing holding portion 13c. In this embodiment, the supply port 13h is an opening portion of the first hole portion 13g that opens on the surface of the first opposing wall portion 13a on the other axial side. The supply port 13h opens into the inside of the motor housing 11. As shown in FIG. 3, the supply port 13h is located above the central axis J1. The supply port 13h opens into the inside of the through portion 13f. When viewed in the axial direction, the supply port 13h overlaps with the through portion 13f.

[0127] In this embodiment, the oil supply passage 95 has a first hole 13g, a second hole 15g, a first gutter 17, and a second gutter 18. As shown by the dashed arrow in Fig. 5, a part of the oil O that is scooped up by the ring gear 62a and enters the second gutter 18 passes through the second hole 15g and flows into the first gutter 17 in the space S. The oil O that flows into the first gutter 17 flows through the first hole 13g and is supplied from the supply port 13h into the motor housing 11. The oil O discharged from the supply port 13h flows into the inside of the bearing holder 13c through the through-hole 13f and is supplied to the bearing 72.

[0128] According to this embodiment, at least a part of the first flow passage 50 is located radially outside the motor 20. Therefore, the motor 20 can be cooled by the water W flowing in the first flow passage 50. In this embodiment, the stator 40 can be cooled by the water W flowing in the first flow passage 50. In addition, at least a part of the recovery flow passage 93 is located radially outside the first flow passage 50. Therefore, the recovery flow passage 93 can be arranged close to the first flow passage 50. As a result, the oil O passing through the recovery flow passage 93 can be easily cooled by the water W flowing in the first flow passage 50. Therefore, the temperature of the oil O flowing from the recovery flow passage 93 into the transmission mechanism housing 12 can be lowered. Therefore, the temperature of the oil O supplied from the inside of the transmission mechanism housing 12 to the inside of the motor housing 11 by the first supply flow passage 91 and the second supply flow passage 92 can be relatively low. As a result, the oil O at a relatively low temperature can be supplied to the motor 20 accommodated in the motor housing 11. Therefore, the motor 20 can be suitably cooled by the oil O at a relatively low temperature. In this manner, in this embodiment, the motor 20 can be suitably cooled by the water W and the oil O. This improves the cooling efficiency of the motor 20. Also, the motor 20 can be easily cooled without providing a cooler such as an oil cooler to cool the oil O. Therefore, the number of parts of the drive device 100 can be reduced by the amount that a cooler is not provided.

[0129] Further, according to this embodiment, the first flow passage 50 extends in a rectangular wave shape along the circumferential direction. Therefore, the portion of the housing 10 where the first flow passage 50 is provided can be made wider, and the motor 20 can be more suitably cooled by the water W flowing in the first flow passage 50. Therefore, the cooling efficiency of the motor 20 can be further improved. Furthermore, when the housing 10 is divided into a plurality of members as in this embodiment, the first flow passage 50 can be easily made by configuring the first flow passage 50 with each member that configures the housing 10. According to this embodiment, at least a portion of the first flow passage 50 is configured by the first housing member 13 and the third housing member 15. Therefore, the first flow passage 50 can be easily elongated on one axial side where the transmission mechanism housing 12 is located. This makes it easy to suitably cool the motor 20 by the first flow passage 50. Here, in this embodiment, as described above, the motor housing 11 and the transmission mechanism housing 12 are each assembled with two housing members, so that the motor housing 11 and the transmission mechanism housing 12 can be separated. Due to this structure, the first flow passage 50 can be formed by utilizing the third housing member 15 constituting the transmission mechanism housing 12, and the first flow passage 50 can be more suitably provided large in the axial direction. In this embodiment, the first flow passage 50 can be extended to one axial side beyond the bearing 72 held by the first opposing wall portion 13a.

[0130] Moreover, in this embodiment, at least a portion of the first circumferential flow passage portion 52a is provided in the third housing member 15. Therefore, a portion of the first flow passage 50 can also be provided in the third housing member 15. This allows the first flow passage 50 to be preferably enlarged in the axial direction, and the motor 20 can be more preferably cooled. Moreover, in this embodiment, at least a portion of the second circumferential flow passage portion 52b is provided in the second housing member 14. Therefore, a portion of the first flow passage 50 can also be provided in the second housing member 14. This allows the first flow passage 50 to be more preferably enlarged in the axial direction, and the motor 20 can be more preferably cooled.

[0131] In this embodiment, the first flow passage 50 can be easily formed by providing a hole 11a penetrating the first housing member 13 in the axial direction and blocking both axial sides of the hole 11a with the second housing member 14 and the third housing member 15. In this embodiment, the opening on one axial side of the hole 11a is blocked by the third housing member 15, and the opening on the other axial side of the hole 11a is blocked by the second housing member 14. At least a part of the inner surface of the first circumferential flow passage portion 52a is the surface of the third housing member 15. At least a part of the inner surface of the second circumferential flow passage portion 52b is the surface of the second housing member 14. Therefore, the first flow passage 50 can be easily formed.

[0132] Moreover, according to this embodiment, the first circumferential flow passage portion 52a is provided across the first housing member 13 and the third housing member 15. Therefore, for example, compared with a case where the entire first circumferential flow passage portion 52a is provided in the third housing member 15, it is possible to suppress an increase in size of the third housing member 15 in the axial direction. This makes it possible to suppress an increase in size of the drive device 100 in the axial direction. In addition, since the first flow passage 50 can be suitably extended to one side in the axial direction beyond the stator 40, it is possible to widen the range of the stator 40 that can be cooled by the first flow passage 50. This makes it possible to more suitably cool the motor 20 by the water W flowing through the first flow passage 50.

[0133] According to the present embodiment, the recovery passage 93 includes a groove 93a provided on the inner circumferential surface of the motor housing 11 and extending in the axial direction, a recovery passage body 93c located radially outward of the groove 93a, extending in the axial direction and connected to the inside of the transmission mechanism housing 12, and a connection portion 93b connecting the groove 93a and the recovery passage body 93c. Therefore, at least a part of the oil O supplied to the motor housing 11 by the first supply passage 91 and the second supply passage 92 can flow from the groove 93a into the recovery passage 93. The oil O that flows into the groove 93a can be sent into the transmission mechanism housing 12 via the connection portion 93b and the recovery passage body 93c. This makes it easier for the recovery passage 93 to return the oil O in the motor housing 11 to the inside of the transmission mechanism housing 12. According to the present embodiment, at least a part of the recovery passage body 93c is located radially outward of the first passage 50. Therefore, the oil O flowing in the recovery passage body 93c is easily cooled by the water W flowing in the first passage 50.

[0134] Further, according to this embodiment, the connection portion 93b connects the other axial end of the groove portion 93a to the other axial end of the recovery flow passage main body 93c. That is, the position where the connection portion 93b connects the groove portion 93a to the recovery flow passage main body 93c can be located at a position relatively far from the transmission mechanism housing 12 in the axial direction. Therefore, the distance that the oil O flows from the connection portion 93b into the recovery flow passage main body 93c until it reaches the inside of the transmission mechanism housing 12 can be increased. This increases the time that the oil O flowing in the recovery flow passage main body 93c can be cooled by the water W flowing in the first flow passage 50. Therefore, the oil O flowing in the recovery flow passage main body 93c can be suitably cooled by the water W flowing in the first flow passage 50. Therefore, it is possible to easily supply the oil O at a lower temperature to the motor 20. This further improves the cooling efficiency of the motor 20.

[0135] According to the present embodiment, the first circumferential flow passage portions 52a include a first circumferential flow passage portion 52c that circumferentially spans one axial side of the groove portion 93a. The connection portion 93b is located between the second circumferential flow passage portions 52b that are adjacent to each other in the circumferential direction. In this way, by having the first circumferential flow passage portion 52c span the groove portion 93a on the axial side opposite to the side where the connection portion 93b is provided, the connection portion 93b can be extended from the radial inner side of the first flow passage 50 to the radial outer side of the first flow passage 50 without interfering with the first flow passage 50. This allows at least a part of the recovery flow passage main body portion 93c to be disposed radially outside the first flow passage 50 without interfering with the first flow passage 50.

[0136] Further, according to the present embodiment, the second supply passage 92 has an introduction passage portion 92a extending in the axial direction from the inside of the transmission mechanism housing 12. At least a part of the introduction passage portion 92a is located radially outside the first passage 50. Therefore, the introduction passage portion 92a can be disposed close to the first passage 50. This makes it easy to cool the oil O passing through the introduction passage portion 92a by the water W flowing through the first passage 50. Therefore, the temperature of the oil O supplied to the inside of the motor housing 11 by the second supply passage 92 can be made relatively low. Therefore, the motor 20 accommodated in the motor housing 11 can be more suitably cooled by the oil O. Therefore, the cooling efficiency of the motor 20 can be further improved.

[0137] Furthermore, according to this embodiment, the introduction flow passage portion 92a is disposed adjacent to the recovery flow passage 93 in the circumferential direction. Therefore, the introduction flow passage portion 92a and the recovery flow passage 93 can be disposed together. This makes it possible to prevent the structure of the housing 10 from becoming complicated.

[0138] Further, according to this embodiment, the recovery passage 93 and the first passage 50 are provided across the first housing member 13 and the second housing member 14, respectively. Therefore, the recovery passage 93 and the first passage 50 can each be enlarged in the axial direction. This makes it easier to increase the portion of the recovery passage 93 that is disposed close to the first passage 50. Therefore, the oil O flowing in the recovery passage 93 can be more easily cooled by the water W flowing in the first passage 50. Furthermore, by enlarging the first passage 50 in the axial direction, the range of the motor 20 that can be cooled by the water W flowing in the first passage 50 can be widened in the axial direction. This makes it easier to cool the entire stator core 41 and the coil ends 42a, 42b protruding from the stator core 41 on both axial sides by the water W flowing in the first passage 50. As a result, the cooling efficiency of the motor 20 can be further improved.

[0139] Further, according to this embodiment, the first housing member 13 and the second housing member 14 are fixed to each other at a position radially inside the recovery passage 93 and adjacent to the first passage 50 in the circumferential direction. In this embodiment, the first housing member 13 and the second housing member 14 are fixed to each other at this position by the fourth bolt 10d fastened to the female screw hole 13i. This allows the first housing member 13 and the second housing member 14 to be fixed to a position close to both the recovery passage 93 and the first passage 50. Therefore, the parts of the first housing member 13 and the second housing member 14 that respectively constitute the recovery passage 93 can be prevented from being separated from each other. Also, the parts of the first housing member 13 and the second housing member 14 that respectively constitute the first passage 50 can be prevented from being separated from each other. This allows the oil O to be prevented from leaking from inside the recovery passage 93 and the water W to be prevented from leaking from inside the first passage 50. In addition, it is possible to prevent the oil O leaking from the recovery passage 93 from entering the first passage 50 and mixing with the water W. In addition, it is possible to prevent the water W leaking from the first passage 50 from entering the recovery passage 93 and mixing with the oil O.

[0140] Furthermore, according to this embodiment, the partition wall 19 has a through hole 19a that connects the inside of the motor housing 11 and the inside of the transmission mechanism housing 12. Therefore, the oil O supplied into the motor housing 11 can be returned into the transmission mechanism housing 12 from the through hole 19a in addition to the recovery passage 93. This makes it possible to increase the amount of oil O returned from the motor housing 11 into the transmission mechanism housing 12.

[0141] For example, in the present embodiment, when the housing 10 is composed of two separate members constituting the motor housing 11 and two separate members constituting the transmission mechanism housing 12, the motor housing 11 and the transmission mechanism housing 12 are provided separately. In such a case, conventionally, a structure for lubricating the bearings was provided separately for each of the motor housing 11 and the transmission mechanism housing 12. This resulted in a problem of an increase in the manufacturing cost of the drive unit 100 due to the complex structure of the housing 10 or the use of relatively expensive bearings that do not require the supply of lubricating oil. The relatively expensive bearings that do not require the supply of lubricating oil are, for example, bearings provided with semi-solid grease.

[0142] In contrast, according to the present embodiment, the housing 10 has an oil supply passage 95 that extends from inside the transmission mechanism housing 12 through the second opposing wall portion 15a in the axial direction. The oil supply passage 95 has a supply port 13h that supplies oil O to the bearing 72 held by the first opposing wall portion 13a in the motor housing 11. The supply port 13h is located above the central axis J1. Therefore, the oil O discharged from the supply port 13h can be made to fall by gravity and supplied to the bearing 72 provided in the motor housing 11 among the bearings that support the rotor 30 rotatable around the central axis J1. In other words, the oil supply passage 95 can supply a part of the oil O in the transmission mechanism housing 12 to the bearing 72 provided in the motor housing 11. In this way, the bearing lubrication structure provided in the transmission mechanism housing 12 can be used to lubricate the bearing 72 provided in the motor housing 11. That is, in the drive unit 100, the motor housing 11 and the transmission mechanism housing 12 are configured to be separable, and the bearing 72 provided in the motor housing 11 can be lubricated using the oil O in the transmission mechanism housing 12. This makes it possible to prevent the structure of the housing 10 from becoming complicated, and there is no need to use a bearing that does not require the supply of lubricating oil as the bearing 72. This makes it possible to prevent an increase in the manufacturing cost of the drive unit 100.

[0143] Furthermore, according to this embodiment, the bearing holding portion 13c is provided on the surface on the other axial side of the first opposing wall portion 13a. The oil supply passage 95 axially penetrates the first opposing wall portion 13a and extends to the inside of the motor housing 11. The supply port 13h opens into the inside of the motor housing 11. Therefore, even if the bearing 72 held by the bearing holding portion 13c is located inside the motor housing 11, the oil supply passage 95 can supply oil O to the bearing 72.

[0144] Furthermore, according to this embodiment, the bearing holder 13c has a through-hole 13f that penetrates the bearing holder 13c in the radial direction. The supply port 13h opens into the inside of the through-hole 13f. Therefore, the oil O discharged from the supply port 13h is easily supplied from the through-hole 13f to the inside of the bearing holder 13c. This makes it easier to supply the oil O to the bearing 72.

[0145] According to the present embodiment, the oil supply passage 95 has a first hole 13g penetrating the first opposing wall 13a in the axial direction, a second hole 15g penetrating the second opposing wall 15a in the axial direction, and a first gutter 17 located between the first opposing wall 13a and the second opposing wall 15a in the axial direction and connecting the first opposing wall 13a and the second opposing wall 15a. The first gutter 17 is connected to a portion of the surface of the first opposing wall 13a on one axial side that is located below the first hole 13g and a portion of the surface of the second opposing wall 15a on the other axial side that is located below the second hole 15g. Therefore, the oil O in the transmission mechanism housing 12 can be supplied to the motor housing 11 via the second hole 15g, the first gutter 17, and the first hole 13g in this order. This allows the oil O in the transmission mechanism housing 12 to be supplied to the bearings 72 in the motor housing 11 more suitably.

[0146] According to the present embodiment, the oil supply passage 95 has the second gutter 18 located inside the transmission mechanism housing 12. The second gutter 18 is connected to a portion of the surface on one axial side of the second opposing wall 15a that is located below the second hole 15g. For this reason, the second gutter 18 can receive a portion of the oil O that is scattered inside the transmission mechanism housing 12 due to, for example, being scooped up by the ring gear 62a. In addition, at least a portion of the oil O received by the second gutter 18 can flow into the second hole 15g. This allows the oil O in the transmission mechanism housing 12 to be more suitably supplied to the bearing 72 in the motor housing 11 via the second hole 15g, the first gutter 17, and the first hole 13g in this order.

[0147] Furthermore, according to this embodiment, the second opposing wall portion 15a has a through hole 15h that connects the space S located between the first opposing wall portion 13a and the second opposing wall portion 15a in the axial direction to the inside of the transmission mechanism housing 12. Therefore, for example, oil O leaking from the first gutter portion 17 can be returned to the inside of the transmission mechanism housing 12 through the through hole 15h. This makes it possible to prevent the oil O from accumulating in the space S.

[0148] Furthermore, according to this embodiment, the first opposing wall portion 13a has a through hole 13e that connects the space S located axially between the first opposing wall portion 13a and the second opposing wall portion 15a to the inside of the motor housing 11. Therefore, the through hole 13e, the space S, and the through hole 15h can connect the inside of the motor housing 11 to the inside of the transmission mechanism housing 12. This forms the above-mentioned through hole 19a, and at least a portion of the oil O supplied to the inside of the motor housing 11 can be returned to the inside of the transmission mechanism housing 12.

[0149] <Second embodiment> At least one of the multiple third protrusions 213m provided on the first housing member 213 in the housing 210 of this embodiment has a pair of opposing portions 213r, 213s arranged with a gap G in between in the axial direction. At least one third protrusion 213m having a pair of opposing portions 213r, 213s is fixed to the fourth protrusion 15m by a second bolt 210b passing through both through holes 213u, 213v provided in the pair of opposing portions 213r, 213s respectively and the gap G. Therefore, the third protrusion 213m can be reduced in weight by the amount of the gap G provided between the opposing portions 213r, 213s in the axial direction. This allows the housing 210 to be reduced in weight. Meanwhile, since the second bolt 210b is passed through each of the through holes 213u, 213v of the pair of opposing portions 213r, 213s, the second bolt 210b can be prevented from tilting in the axial direction. The through hole 213u penetrates the opposing portion 213r in the axial direction. The through hole 213v penetrates the opposing portion 213s in the axial direction. The second bolt 210b that fixes the pair of opposing portions 213r, 213s has an exposed portion 210e that passes through the gap G and is exposed to the outside of the housing 210.

[0150] In this embodiment, all of the multiple third protrusions 213m have a pair of opposing portions 213r, 213s. In this embodiment, each third protrusion 213m has a connection portion 213t that connects the opposing portion 213r and the opposing portion 213s in the axial direction. The connection portion 213t connects the radially inner portion of the opposing portion 213r and the radially inner portion of the opposing portion 213s in the axial direction. The connection portion 213t is located radially inside the exposed portion 210e. The axial dimension of the connection portion 213t is the same as the axial dimension of the gap G. The axial dimension of the connection portion 213t is larger than the axial dimension of the opposing portions 213r, 213s. The axial dimension of the connection portion 213t is, for example, three times or more the axial dimension of the opposing portions 213r, 213s. The opposing portion 213r is an end portion on the other axial side of the third protrusion 213m. The facing portion 213s is an end portion on one axial side of the third protruding portion 213m. The facing portion 213s is in contact with the fourth protruding portion 15m.

[0151] Other configurations of the housing 210 can be similar to other configurations of the housing 10 of the first embodiment. Note that in this embodiment, only some of the multiple third protrusions 213m may have the pair of opposing portions 213r, 213s, and the other third protrusions 213m may have the same configuration as the third protrusions 13m of the first embodiment. The third protrusions 13m having the pair of opposing portions 213r, 213s may not have the connection portion 213t.

[0152] The present invention is not limited to the above-described embodiment, and other configurations and methods may be adopted within the scope of the technical concept of the present invention. The second flow path may have any configuration as long as it has a supply flow path and a recovery flow path. In the above-described embodiment, the supply flow path is configured to include the first supply flow path 91 and the second supply flow path 92, but is not limited to this. Only one of the first supply flow path 91 and the second supply flow path 92 may be provided as the supply flow path.

[0153] The recovery passage extending from the inside of the motor housing to the inside of the transmission mechanism housing may have any configuration as long as at least a portion is located radially outside the first passage. When the motor housing has a first housing member and a second housing member, the recovery passage may be provided only in the first housing member in the motor housing. The shape and size of the groove portion, the shape and size of the connection portion, and the shape and size of the recovery passage main body portion are not particularly limited. The groove portion and the connection portion do not have to be provided.

[0154] The first flow passage may have any shape. The first circumferential flow passage portion may not be provided across the first housing member and the third housing member. The second circumferential flow passage portion may not be provided across the first housing member and the second housing member. The first flow passage may extend in a rectangular wave shape along the axial direction, for example, by connecting axial ends of a plurality of flow passage portions that extend in the circumferential direction and are arranged at intervals in the axial direction. The first flow passage may extend in a spiral shape. The number of axial flow passage portions is not particularly limited as long as it is two or more. The number of the first circumferential flow passage portions and the number of the second circumferential flow passage portions are not particularly limited as long as it is one or more.

[0155] The type of the first fluid flowing inside the first flow path and the type of the second fluid flowing inside the second flow path are not particularly limited. The first fluid and the second fluid may be the same type of fluid. The second fluid may be an insulating liquid or may be water. When the second fluid is water, an insulating treatment may be applied to the surface of the stator. The first fluid may be oil. At least one of the first flow path and the second flow path may not be provided.

[0156] The oil supply passage extending from inside the transmission mechanism housing through the second opposing wall in the axial direction may have any configuration as long as it has a supply port located above the central axis and supplies oil to the bearing. When the bearing holder provided on the first opposing wall of the motor housing is provided on one axial side of the first opposing wall, that is, on the surface of the first opposing wall facing the transmission mechanism housing, the oil supply passage may only pass through the second opposing wall and not through the first opposing wall. In this case, for example, the supply port of the oil supply passage opens into the space between the first opposing wall and the second opposing wall. The oil supply passage may not have at least one of the first hole, the second hole, the first gutter, and the second gutter. The oil supply passage may be formed of a tubular member such as a pipe. The oil supply passage may not be provided.

[0157] The use of the drive device to which the present invention is applied is not particularly limited. For example, the drive device may be mounted on a vehicle for a purpose other than rotating an axle, or may be mounted on equipment other than a vehicle. The attitude of the drive device when 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 may extend in the vertical direction. The configurations described in this specification above can be appropriately combined within a range that does not contradict each other. [Explanation of symbols]

[0158] 10,210...housing, 10a...first bolt, 10b,210b...second bolt, 10c...third bolt, 11...motor housing, 11a...hole, 12...transmission mechanism housing, 13,213...first housing member, 13a...first opposing wall portion, 13c...bearing retaining portion, 13k...first protrusion, 13m,213m...third protrusion, 13x,13y,14x,15y...fastening surface, 14...second housing member, 14k...second protrusion, 15...third housing member, 15 a...second opposing wall portion, 15m...fourth protrusion portion, 16...fourth housing member, 20...motor, 30...rotor, 40...stator, 50...first flow passage, 51, 51c...axial flow passage portion, 52a, 52c...first circumferential flow passage portion, 52b...second circumferential flow passage portion, 60...transmission mechanism, 72...bearing, 90...second flow passage, 92d, 93h...flow passage portion (first portion), 92f, 93j...flow passage portion (second portion), 100...drive device, 213r, 213s...opposing portion, G...gap, J1...central axis

Claims

1. A motor having a rotor rotatable about a central axis and a stator covering the outside of the rotor in a radial direction; A transmission mechanism connected to the motor; a housing including a motor housing that accommodates the motor therein, and a transmission mechanism housing that is fixed to one axial side of the motor housing and accommodates the transmission mechanism therein; Equipped with The motor housing includes: a first housing member fixed to the transmission mechanism housing; a second housing member fixed to the other axial side of the first housing member by a plurality of first bolts; having The transmission mechanism housing includes: a third housing member fixed to the first housing member by a plurality of second bolts; a fourth housing member fixed to one axial side of the third housing member by a plurality of third bolts; having the first bolts that fix the first housing member and the second housing member are passed through a plurality of through holes provided in the second housing member from the other axial side, respectively, and fixed to a plurality of bolt holes provided in the first housing member, the second bolts that fix the first housing member and the third housing member are passed through a plurality of through holes provided in the first housing member from the other axial side, respectively, and fixed to a plurality of bolt holes provided in the third housing member, the third bolts that fix the third housing member and the fourth housing member are passed through a plurality of through holes provided in the fourth housing member from one axial side, respectively, and fixed to a plurality of bolt holes provided in the third housing member, The housing includes: a first flow path through which a first fluid flows; a second flow path through which a second fluid different in type from the first fluid flows; having At least a portion of the first flow path is defined by the first housing member and the third housing member, At least a portion of the second flow path is defined by the first housing member and the third housing member, a fastening surface between the first housing member and the third housing member which are fixed to each other by the second bolt is a sealing surface which seals a portion of the first flow path at the connection portion between the first housing member and the third housing member, and is a sealing surface which seals a portion of the second flow path at the connection portion between the first housing member and the third housing member.

2. 2. The drive device of claim 1, wherein the plurality of first bolts fixing the first housing member and the second housing member fix a plurality of first protrusions provided on an outer peripheral surface of the first housing member and a plurality of second protrusions provided on an outer peripheral surface of the second housing member, respectively.

3. 3. The drive device described in claim 1 or claim 2, wherein the plurality of second bolts fixing the first housing member and the third housing member fix a plurality of third protrusions provided on the outer peripheral surface of the first housing member and a plurality of fourth protrusions provided on the outer peripheral surface of the third housing member, respectively.

4. The third bolts that fix the third housing member and the fourth housing member fix a plurality of fifth protrusions provided on an outer peripheral surface of the third housing member and a plurality of sixth protrusions provided on an outer peripheral surface of the fourth housing member, respectively; the first bolts and the second bolts are disposed at different positions from each other in a circumferential direction around the central axis, The drive device according to claim 3 , wherein at least one of the plurality of third bolts overlaps with the second bolt when viewed in the axial direction.

5. A motor having a rotor rotatable around a central axis and a stator covering the radial outside of the rotor; A transmission mechanism connected to the motor; a housing including a motor housing that accommodates the motor therein, and a transmission mechanism housing that is fixed to one axial side of the motor housing and accommodates the transmission mechanism therein; Equipped with The motor housing includes: a first housing member fixed to the transmission mechanism housing; a second housing member fixed to the other axial side of the first housing member by a plurality of first bolts; having The transmission mechanism housing includes: a third housing member fixed to the first housing member by a plurality of second bolts; a fourth housing member fixed to one axial side of the third housing member by a plurality of third bolts; having the first bolts that fix the first housing member and the second housing member are passed through a plurality of through holes provided in the second housing member from the other axial side, respectively, and fixed to a plurality of bolt holes provided in the first housing member, the second bolts that fix the first housing member and the third housing member are passed through a plurality of through holes provided in the first housing member from the other axial side, respectively, and fixed to a plurality of bolt holes provided in the third housing member, the third bolts that fix the third housing member and the fourth housing member are passed through a plurality of through holes provided in the fourth housing member from one axial side, respectively, and fixed to a plurality of bolt holes provided in the third housing member, the first bolts that fix the first housing member and the second housing member fix a plurality of first protrusions provided on an outer circumferential surface of the first housing member and a plurality of second protrusions provided on an outer circumferential surface of the second housing member, respectively; the second bolts that fix the first housing member and the third housing member fix a plurality of third protrusions provided on an outer circumferential surface of the first housing member and a plurality of fourth protrusions provided on an outer circumferential surface of the third housing member, respectively; the third bolts that fix the third housing member and the fourth housing member fix a plurality of fifth protrusions provided on an outer circumferential surface of the third housing member and a plurality of sixth protrusions provided on an outer circumferential surface of the fourth housing member, respectively; the first bolts and the second bolts are disposed at different positions from each other in a circumferential direction around the central axis, A drive device, wherein at least one of the plurality of third bolts overlaps with the second bolt when viewed in the axial direction.

6. 6. A drive device as described in any one of claims 3 to 5, wherein at least one of the multiple third protrusions has a pair of opposing portions arranged with a gap in the axial direction, and is fixed to the fourth protrusion by the second bolt passing through both of the through holes provided in each of the pair of opposing portions and the gap.

7. Further comprising a bearing for rotatably supporting the rotor; The first housing member includes: a first opposing wall portion that faces the third housing member in the axial direction; a bearing holder provided on the first opposing wall and holding the bearing; having The first flow path is A plurality of axial flow passages extending in an axial direction and arranged at intervals in a circumferential direction; a first circumferential flow passage portion connecting one axial end portion of the axial flow passage portions adjacent to each other in the circumferential direction; a second circumferential flow passage portion connecting the other axial end portions of the axial flow passage portions adjacent to each other in the circumferential direction; The drive unit according to claim 1 , wherein the first and second grooves extend in a rectangular wave shape along the circumferential direction.

8. The axial flow passage portion is formed by at least a portion of a hole that axially penetrates the first housing member, an opening on one axial side of the hole is closed by the third housing member, The opening of the hole on the other axial side is closed by the second housing member, At least a part of an inner surface of the first circumferential flow path portion is a surface of the third housing member, The drive unit according to claim 7 , wherein at least a portion of an inner surface of the second circumferential flow path portion is a surface of the second housing member.

9. At least a portion of the first circumferential flow path portion is provided in the third housing member, The drive unit according to claim 8 , wherein at least a portion of the second circumferential flow path portion is provided in the second housing member.

10. The second flow path is a first portion provided on the first housing member; a second portion provided in the third housing member and connected to one axial side of the first portion; The drive arrangement according to any one of claims 7 to 9, comprising:

11. the third housing member has a second opposing wall portion axially opposing the first opposing wall portion, The drive device according to claim 10 , wherein the second portion axially passes through the second opposing wall and opens into the interior of the transmission mechanism housing.

12. The drive device according to claim 1 , wherein the first bolts and the second bolts are arranged alternately with each other along a circumferential direction around the central axis when viewed in the axial direction.

13. The first bolts are disposed at equal intervals around a circumference in a circumferential direction about the central axis, The drive device according to claim 1 , wherein the second bolts are disposed at equal intervals around one circumference in a circumferential direction about the central axis.

14. the housing has a flow passage through which a coolant for cooling the stator flows, The drive device according to claim 1 , wherein at least a portion of the flow path is defined by the first housing member, the second housing member, and the third housing member.

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