Rotating electric machine and drive device

Abstract

A drive device according to an aspect of the present invention comprises: a rotor that can rotate about the central axis; a stator that faces the rotor in the radial direction; a housing that houses the rotor and the stator; and a first flow path and a second flow path that are independent of each other. The housing has a bearing holder that is positioned on one side in the axial direction of the stator and supports the rotor via a bearing. The first flow path has a first heat exchange flow path part provided inside the bearing holder. The second flow path has a second heat exchange flow path part provided inside the bearing holder. The bearing holder has a wall part that partitions the first heat exchange flow path part and the second heat exchange flow path part.

Description

Rotating electric machine and drive unit

[0001] This application claims priority to U.S. Provisional Application No. 63 / 661,628, filed June 19, 2024, the contents of which are incorporated herein by reference.

[0002] BACKGROUND ART Vehicles using a rotating electric machine as a drive source, such as electric vehicles or hybrid vehicles, are provided with a cooling circuit for cooling the rotating electric machine. A cooling system is known that cools the rotating electric machine by supplying oil cooled by an oil cooler disposed outside the case to the rotating electric machine inside the case (for example, see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2020-61859

[0004] When a rotating electrical machine is cooled using a fluid, there is a problem that the rotating electrical machine becomes large in size depending on the arrangement of the heat exchanger.

[0005] In view of the above circumstances, an object of the present invention is to provide a rotating electric machine and a drive device that can be made smaller in size.

[0006] One aspect of the rotating electric machine of the present invention includes a rotor rotatable about a central axis, a stator radially opposed to the rotor, a housing portion that houses the rotor and the stator, and first and second flow paths that are independent of each other. The housing portion has a bearing holder located on one axial side of the stator and supporting the rotor via a bearing. The first flow path has a first heat exchange flow path portion provided inside the bearing holder. The second flow path has a second heat exchange flow path portion provided inside the bearing holder. The bearing holder has a wall portion that separates the first and second heat exchange flow path portions.

[0007] One aspect of the drive device of the present invention is a drive device including the above-described rotating electric machine and a power transmission mechanism connected to the rotor.

[0008] According to one aspect of the present invention, it is possible to provide a rotating electric machine and a drive device that can be made smaller in size.

[0009] FIG. 1 is a schematic diagram of a drive device according to an embodiment. FIG. 2 is an exploded perspective view of a drive device according to an embodiment. FIG. 3 is an exploded perspective view of a drive device according to an embodiment. FIG. 4 is a cross-sectional view of a drive device according to an embodiment. FIG. 5 is a front view of a drive device according to an embodiment. FIG. 6 is a cross-sectional view of a drive device according to a first modified example. FIG. 7 is a cross-sectional view of a drive device according to a second modified example.

[0010] A rotating electric machine and a drive unit according to an embodiment of the present invention will be described below with reference to the drawings. In the following description, the vertical direction will be defined based on the positional relationship when the drive unit according to the embodiment shown in each figure is mounted on a vehicle positioned on a horizontal road surface. The drawings also illustrate an XYZ coordinate system as a three-dimensional Cartesian coordinate system, as appropriate. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the upper side, and the −Z side is the lower side. In the following description, the upper side in the vertical direction will be simply referred to as the “upper side,” and the lower side in the vertical direction will be simply referred to as the “lower side.” The X axis direction is perpendicular to the Z axis direction and corresponds to the front-to-rear direction of the vehicle on which the drive unit is mounted. The Y axis direction is perpendicular to both the X axis direction and the Z axis direction and corresponds to the left-to-right direction of the vehicle, i.e., the vehicle width direction. The front-to-rear direction and the left-to-right direction are horizontal directions perpendicular to the vertical direction.

[0011] The center axis J1 shown in each drawing as appropriate is a virtual line extending in the Y-axis direction, i.e., in the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the center axis J1 will be simply referred to as the "axial direction," the radial direction about the center axis J1 will be simply referred to as the "radial direction," and the circumferential direction about the center axis J1, i.e., around the center axis J1, will be simply referred to as the "circumferential direction." In the following description, the +Y side may be simply referred to as one axial side, and the -Y side may be simply referred to as the other axial side. Similarly, the +X side may be simply referred to as one front-rear side, and the -X side may be simply referred to as the other front-rear side.

[0012] In each figure, the circumferential direction is indicated by an arrow θ. The side of the circumferential direction toward which the arrow θ points (+θ side) is called the "one circumferential side." The opposite side of the circumferential direction to the side toward which the arrow θ points (-θ side) is called the "other circumferential side." The one circumferential side is the side that advances counterclockwise around the central axis J1 when viewed from one axial side (+Y). The other circumferential side is the side that advances clockwise around the central axis J1 when viewed from one axial side (+Y).

[0013] 1 is a schematic diagram of a drive unit 1 according to this embodiment. The drive unit 1 is mounted on a vehicle that uses a rotating electric machine as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as the power source thereof.

[0014] The drive device 1 includes a rotating electric machine 2, a power transmission mechanism 3, a control unit 7, and a pump 8. As will be described later, the rotating electric machine 2 includes a first housing portion (housing portion) 6A, the power transmission mechanism 3 includes a second housing portion 6B, and the control unit 7 includes a third housing portion 6C. The first housing portion 6A, the second housing portion 6B, and the third housing portion 6C are connected to one another to form a housing 6. That is, the drive device 1 includes the housing 6.

[0015] (Rotating Electric Machine) In this embodiment, the rotating electric machine 2 is an inner rotor type motor. In addition, the rotating electric machine 2 in this embodiment is, for example, a three-phase AC motor. The rotating electric machine 2 may have only one of the functions as an electric motor and the function as a generator, or may have both of these functions. The configuration of the rotating electric machine 2 is not limited to this embodiment. The rotating electric machine 2 may be, for example, an outer rotor type motor or a DC motor.

[0016] The rotating electric machine 2 includes a rotor 20, a stator 30, a bus bar 90, a rotational position sensor 50, and a first housing portion 6A. The rotor 20 and the stator 30 constitute a motor main body 2a. That is, the motor main body 2a is made up of the rotor 20 and the stator 30.

[0017] The first accommodating portion 6A accommodates the rotor 20, the stator 30, the bus bar 90, and the rotational position sensor 50. The detailed configuration of the first accommodating portion 6A will be described later as part of the housing 6.

[0018] The rotor 20 is rotatable about a central axis J1. Torque of the rotor 20 is transmitted to the power transmission mechanism 3. The rotor 20 has a motor shaft 21 extending axially about the central axis J1, a rotor core 24 fixed to the outer peripheral surface of the motor shaft 21, and a rotor magnet (not shown) fixed to the rotor core 24. In this embodiment, the motor shaft 21 is a hollow shaft having a hollow portion 22 therein.

[0019] The stator 30 faces the rotor 20 in the radial direction. The stator 30 surrounds the rotor 20 from the radial outside. The stator 30 has a stator core 32, a coil 31, and an insulating member (not shown) interposed between the stator core 32 and the coil 31. The stator 30 is held in the first housing portion 6A. The stator core 32 has a plurality of magnetic pole teeth (not shown) that protrude radially inward from the inner circumferential surface of the annular yoke. A coil wire is arranged between the magnetic pole teeth via an insulating member. The coil wire located between adjacent magnetic pole teeth constitutes the coil 31. The insulating member is, for example, insulating paper.

[0020] The stator core 32 of this embodiment is provided with a groove 32g, a plurality of first holes 32a, and a plurality of second holes 32b. The groove 32g is provided on the outer peripheral surface of the stator core 32 facing radially outward. The groove 32g extends in an annular shape along the circumferential direction. The groove 32g is located approximately in the axial center of the stator core 32. The plurality of first holes 32a extend from the groove 32g toward one axial side (+Y) and open at the end face of the stator core 32 on the one axial side (+Y). The plurality of second holes 32b extend from the groove 32g toward the other axial side (-Y) and open at the end face of the stator core 32 on the other axial side (-Y). In this embodiment, the plurality of first holes 32a and the plurality of second holes 32b are arranged at equal intervals in the circumferential direction. The first holes 32a and the second holes 32b may be arranged unevenly in the circumferential direction.

[0021] The coil 31 in this embodiment is composed of multiple coil wires. Alternatively, the coil 31 may be composed of multiple rod-shaped conductors connected together. The coil 31 has coil ends 31a that protrude from both axial ends of the stator core 32. That is, the stator 30 has coil ends 31a located on one axial side (+Y) and the other axial side (-Y).

[0022] The busbar 90 is located on one axial side (+Y) of the stator 30. The busbar 90 overlaps the coil end 31a in the axial direction. The busbar 90 is a plate-shaped member made of a metal material with low electrical resistance (e.g., a copper alloy). The drive device 1 of this embodiment is provided with three busbars 90 corresponding to the U phase, V phase, and W phase. The three busbars 90 are supported by a busbar 90 holder made of, for example, a resin material. One end of the busbar 90 is connected to the coil wire extending from the coil 31, and the other end of the busbar 90 is connected to the control unit 7. In other words, the busbar 90 connects the control unit 7 and the stator 30.

[0023] The rotational position sensor 50 detects the rotational position of the rotor 20. In this embodiment, the rotational position sensor 50 is, for example, a resolver. The rotational position sensor 50 has a sensor rotor 51 and a sensor main body 52. ​​The sensor rotor 51 has a plurality of magnets arranged in the circumferential direction. The sensor rotor 51 rotates around the central axis J1 together with the rotor 20. The sensor main body 52 is supported by the bearing holder 80. The sensor main body 52 is annular and surrounds the sensor rotor 51 from the radially outer side. The sensor main body 52 has a coil that is excited by changes in magnetic flux that accompany the rotation of the sensor rotor 51. The sensor main body 52 detects the rotation angle of the rotor 20 based on the changes in the excited magnetic flux.

[0024] (Control Unit) The control unit 7 is electrically connected to the stator 30 via the bus bar 90. The control unit 7 controls the current supplied to the stator 30. The control unit 7 is, for example, an inverter. In this case, the control unit 7 has electronic components such as a power board, a capacitor, and a switching element, and converts direct current supplied from a battery (not shown) into alternating current. The control unit 7 also has a third housing portion 6C that houses the electronic components.

[0025] (Power Transmission Mechanism) The power transmission mechanism 3 is located on the other axial side (-Y) of the rotating electric machine 2. The power transmission mechanism 3 is connected to the rotor 20. The power transmission mechanism 3 transmits the rotation of the rotor 20 to the output shaft 5a.

[0026] The power transmission mechanism 3 includes a first shaft 44, a second shaft 45, a first gear 41, a second gear 42, a third gear 43, a differential device 5, and a second housing portion 6B. The differential device 5 includes a ring gear 5g and a pair of output shafts 5a. Wheels (not shown) are connected to the pair of output shafts 5a, respectively. The second housing portion 6B houses the first shaft 44, the second shaft 45, the first gear 41, the second gear 42, the third gear 43, and the differential device 5.

[0027] The first shaft 44 is disposed on the same line as the motor shaft 21. The first shaft 44 is coupled to the motor shaft 21 and rotates together with the rotor 20. The first gear 41 is provided on the outer peripheral surface of the first shaft 44. The second shaft 45 rotates about an intermediate axis J2 parallel to the central axis J1. The second gear 42 and the third gear 43 are provided on the outer peripheral surface of the second shaft 45. The second gear 42 meshes with the first gear 41. The third gear 43 meshes with a ring gear 5g of the differential device 5. The differential device 5 rotates about an output axis J3 parallel to the central axis J1. When the vehicle turns, the differential device 5 transmits torque transmitted from the third gear 43 to the output shaft 5a while absorbing the speed difference between the left and right wheels. The torque output from the rotating electric machine 2 is transmitted to the ring gear 5g of the differential device 5 via the first gear 41, the second gear 42, the second shaft 45 and the third gear 43, and is output to a pair of output shafts 5a via the differential mechanism part of the differential device 5.

[0028] (Housing) The housing 6 has a first housing portion 6A, a second housing portion 6B, and a third housing portion 6C. The first housing portion 6A houses each component of the rotating electric machine 2. The second housing portion 6B houses each component of the power transmission mechanism 3. The second housing portion 6B is located on the other axial side (-Y) of the first housing portion 6A. The third housing portion 6C houses each component of the control unit 7. The third housing portion 6C is located above the first housing portion 6A. The first housing portion 6A, the second housing portion 6B, and the third housing portion 6C may be separate members that are connected to each other, or may be portions of a single member.

[0029] The housing 6 is also provided with a first flow path 60 and a second flow path 70. That is, the drive unit 1 includes the first flow path 60 and the second flow path 70. The first flow path 60 and the second flow path 70 are flow paths independent of each other. Therefore, the first flow path 60 and the second flow path 70 constitute at least a part of different circulation paths. Furthermore, the fluid flowing through the first flow path 60 (hereinafter referred to as the first fluid O) and the fluid flowing through the second flow path 70 (hereinafter referred to as the second fluid W) do not mix with each other.

[0030] In the present embodiment, the first fluid O is, for example, oil, and the second fluid W is, for example, cooling water. However, the types of the first fluid O and the second fluid W are merely examples. However, of the two fluids (first fluid O and second fluid W), the fluid that flows into the internal space of the first housing portion 6A (first fluid O in the present embodiment) is preferably an insulating liquid to prevent short-circuiting of the coil 31.

[0031] The first housing 6A has an outer peripheral wall 6d, a bottom wall 6e, a cover 6k, a bearing holder 80, and two fluid guides 87A and 87B. The outer peripheral wall 6d, the bottom wall 6e, and the cover 6k surround the motor main body 2a, forming a space in which the motor main body 2a is disposed. In this embodiment, the bearing holder 80 and the two fluid guides 87A and 87B are disposed in the internal space of the first housing 6A together with the motor main body 2a.

[0032] The outer peripheral wall portion 6d is cylindrical and surrounds the central axis J1 from the radially outward side. The outer peripheral wall portion 6d surrounds the motor main body portion 2a from the radially outward side. The stator 30 is fixed to the inner peripheral surface of the outer peripheral wall portion 6d. The inner peripheral surface of the outer peripheral wall portion 6d is provided with a stepped surface 6f facing one axial side (+Y). The stepped surface 6f is located on one axial side (+Y) of the motor main body portion 2a. A bearing holder 80 is fixed to the stepped surface 6f. Furthermore, a portion of the outer peripheral wall portion 6d located above the motor main body portion 2a constitutes part of the third housing portion 6C. In this embodiment, the control unit 7 is fixed to the surface of the outer peripheral wall portion 6d facing radially outward.

[0033] The bottom wall portion 6e is plate-shaped and extends along a plane perpendicular to the central axis J1. The bottom wall portion 6e is connected to the end of the outer peripheral wall portion 6d on the other axial side (-Y). The bottom wall portion 6e is located on the other axial side (-Y) of the motor main body 2a. A first through-hole 6h is provided in the bottom wall portion 6e. The motor shaft 21 and the first shaft 44 pass through the first through-hole 6h. A bearing 4B that rotatably supports the motor shaft 21 is also disposed in the first through-hole 6h. The bottom wall portion 6e supports the rotor 20 via the bearing 4B.

[0034] The cover 6k is a plate-like member extending along a plane perpendicular to the central axis J1. The cover 6k is fixed to an end portion of the outer peripheral wall portion 6d on one axial side (+Y). The cover 6k covers an opening on one axial side (+Y) of the outer peripheral wall portion 6d. The cover 6k is located on one axial side (+Y) of the motor main body 2a.

[0035] (Bearing Holder) The bearing holder 80 supports the bearing 4A. The bearing 4A rotatably supports the motor shaft 21. Therefore, the bearing holder 80 supports the rotor 20 via the bearing 4A.

[0036] The bearing holder 80 is provided with a first holder internal flow path portion 66 and a second holder internal flow path portion 76. The first holder internal flow path portion 66 is a part of the first flow path 60. The second holder internal flow path portion 76 is a part of the second flow path 70. The first holder internal flow path portion 66 has a first inflow flow path portion 64A, a first heat exchange flow path portion 63, and a first outflow flow path portion (outflow flow path portion) 64B. The second holder internal flow path portion 76 has a second inflow flow path portion 74A, a second heat exchange flow path portion 73, and a second outflow flow path portion 74B.

[0037] The bearing holder 80 is located on one axial side (+Y) of the motor main body 2a and on the other axial side (-Y) of the cover 6k. The bearing holder 80 is fixed to the stepped surface 6f of the outer peripheral wall 6d. Note that the fixed position of the bearing holder 80 relative to the outer peripheral wall 6d is not limited to this embodiment. For example, the bearing holder 80 may be fixed to the end of the outer peripheral wall 6d on one axial side (+Y).

[0038] A second through-hole 80h is provided in the bearing holder 80. The motor shaft 21 is passed through the second through-hole 80h. The bearing 4A and the sensor main body 52, which is located on one axial side (+Y) of the bearing 4A, are also disposed in the second through-hole 80h.

[0039] 2 and 3 are exploded perspective views of the bearing holder 80 as viewed from different directions. The bearing holder 80 has a holder main body 81, a first lid (lid portion) 88, and a second lid portion 89. The first lid portion 88 is fixed to the holder main body 81 from the other axial side (-Y). The second lid portion 89 is fixed to the holder main body 81 from one axial side (+Y).

[0040] The holder main body 81 is made of a metal material such as an aluminum alloy to ensure sufficient rigidity. Meanwhile, the first lid 88 is made of a resin material, for example. The first lid 88 is disposed on the motor main body 2a side of the bearing holder 80. By using an insulating material for the first lid 88, the bearing holder 80 can be disposed closer to the motor main body 2a. This allows the rotating electric machine 2 to be downsized in the axial direction. Furthermore, the thermal conductivity of resin materials is generally lower than that of metal materials. Therefore, by disposing the first lid 88 on the side of the bearing holder 80 closer to the motor main body 2a, the first fluid O flowing through the first-holder internal flow path 66 and the second fluid W flowing through the second-holder internal flow path 76 can be prevented from being heated by the motor main body 2a. In addition, as long as the thermal conductivity of the material constituting the first lid portion 88 is lower than the thermal conductivity of the material constituting the holder main body portion 81, the material constituting the first lid portion 88 and the second lid portion 89 is not particularly limited, and may be a metal material or a resin material.

[0041] The first lid portion 88 is fixed to the holder main body portion 81 by, for example, screwing or adhesive. When the first lid portion 88 and the holder main body portion 81 are both made of a metal material, the first lid portion 88 and the holder main body portion 81 may be fixed by friction stir welding. When fixed by friction stir welding, it is preferable that the first lid portion 88 is provided inside a first groove portion 81b described below and be joined along a mating surface with a second surface 82b described below. Similarly, the second lid portion 89 is fixed to the holder main body portion 81 by, for example, screwing or adhesive. When the second lid portion 89 and the holder main body portion 81 are both made of a metal material, the second lid portion 89 and the holder main body portion 81 may be fixed by friction stir welding. When fixed by friction stir welding, it is preferable that the second lid portion 89 is provided inside a second groove portion 81c described below and be joined along a mating surface with a first surface 82a described below.

[0042] 2 and 3, the holder main body 81 has a plate portion 82, a first retaining cylindrical portion 83, a second retaining cylindrical portion 86, a wall portion 84, and a boss 85. The plate portion 82 extends along a plane perpendicular to the central axis J1. The plate portion 82 is provided with the second through-hole 80h described above. The plate portion 82 has a first surface 82a facing one axial side (+Y) and a second surface 82b facing the other axial side (-Y).

[0043] As shown in Figure 2, the first retaining cylindrical portion 83 protrudes from the second surface 82b toward the other axial side (-Y). The first retaining cylindrical portion 83 is substantially cylindrical and centered on the central axis J1. The first retaining cylindrical portion 83 extends along the axial direction and defines a second through-hole 80h. The first retaining cylindrical portion 83 holds the bearing 4A (see Figure 1) from the radially outer side.

[0044] As shown in Figure 3, the second retaining cylindrical portion 86 protrudes from the first surface 82a toward one axial side (+Y). The second retaining cylindrical portion 86 is generally cylindrical and centered on the central axis J1. The second retaining cylindrical portion 86 holds the bearing 4A from the radially outer side. The second retaining cylindrical portion 86 also holds the sensor body 52 (see Figure 1) of the rotational position sensor 50 from the radially outer side.

[0045] As shown in FIG. 2 , the wall portion 84 protrudes from the second surface 82b toward the other axial side (−Y). The wall portion 84 includes an arc-shaped wall portion 84a and a linear wall portion 84b. In this embodiment, the arc-shaped wall portion 84a extends in a generally arc-like shape centered on the central axis J1 and passing through the other front-rear direction side (−X) when viewed from the axial direction. The end of the arc-shaped wall portion 84a on one circumferential side (+θ) is located above the central axis J1, and the end of the arc-shaped wall portion 84a on the other circumferential side (−θ) is located below the central axis J1. The linear wall portion 84b extends linearly from the end of the arc-shaped wall portion 84a on the other circumferential side (−θ) toward the one front-rear direction side (+X). The arc-shaped wall portion 84a does not necessarily have to have an arc-like shape when viewed in the axial direction, but may have a curved shape that extends radially around the center axis J1 from the outside. The linear wall portion 84b does not necessarily have to extend linearly, but may have a shape that is at least partially curved. Furthermore, the wall portion 84 may not have the linear wall portion 84b, and may be composed of only the arc-shaped wall portion 84a, for example.

[0046] The wall portion 84 has a tip surface 84f facing the other axial side (-Y). The tip surface 84f is provided with a first groove portion (groove portion) 81b recessed toward one axial side (+Y). In other words, the first groove portion 81b is provided on the surface of the holder main body portion 81 facing the other axial side (-Y).

[0047] The first groove 81b extends over the entire length of the wall 84. Accordingly, the first groove 81b has a first arc portion 81ba and a first linear portion 81bb. The first arc portion 81ba of the first groove 81b is provided in the arc-shaped wall portion 84a of the wall 84. The first linear portion 81bb of the first groove 81b is provided in the linear wall portion 84b of the wall 84. In this embodiment, the first arc portion 81ba extends in a generally arc-like shape centered on the central axis J1 and passing through the other side (-X) in the front-rear direction, as viewed from the axial direction. The end of the first arc portion 81ba on one circumferential side (+θ) is located above the central axis J1, and the end of the first arc portion 81ba on the other circumferential side (-θ) is located below the central axis J1. The first straight portion 81bb extends linearly from the other circumferential side (-θ) end of the first arc portion 81ba toward one front-rear direction side (+X). Note that the first arc portion 81ba does not necessarily have an arc-like shape when viewed in the axial direction, but may have a curved shape that surrounds the central axis J1 from the radially outer side. The first straight portion 81bb does not necessarily have to extend linearly, but may have a shape that is at least partially curved. Furthermore, the first groove portion 81b may, for example, not have the first straight portion 81bb and may be composed only of the first arc portion 81ba.

[0048] A plurality of first protrusions 81d are provided on the bottom surface of the first groove portion 81b. The plurality of first protrusions 81d protrude from the bottom surface of the first groove portion 81b toward the other axial side (-Y). In this embodiment, the first protrusions 81d are plate-shaped. The plurality of first protrusions 81d extend along the extension direction of the first groove portion 81b at their respective locations. That is, the first protrusions 81d or portions of the first protrusions 81d arranged on the first arc portion 81ba are curved along the extension direction of the first arc portion, and the first protrusions 81d or portions of the first protrusions 81d arranged on the first linear portion 81bb extend in a substantially linear manner along the extension direction of the first linear portion 81bb. Furthermore, the first protrusions 81d do not necessarily have to extend along the direction in which the first groove portions 81b extend at each location, and at least some of the multiple first protrusions 81d may extend in a direction other than the direction in which the first groove portions 81b extend.

[0049] A second outlet flow path 74B is provided in the tip surface 84f of the wall portion 84. The second outlet flow path 74B is a hole that axially penetrates the tip surface 84f of the wall portion 84. The second outlet flow path 74B is located further to the one side (+X) in the front-rear direction of the end portion on one side (+X) in the front-rear direction of the linear wall portion 84b.

[0050] The boss 85 protrudes from the second surface 82b toward the other axial side (-Y). The boss 85 is located toward one side (+X) in the front-rear direction relative to the end of the arc-shaped wall portion 84a on one circumferential side (+θ). The boss 85 is located above the second outlet flow passage 74B. The boss 85 has a tip surface 85f facing the other axial side (-Y). The tip surface 85f of the boss 85 is provided with the second inlet flow passage 74A. The second inlet flow passage 74A is a hole that axially penetrates the tip surface 85f of the boss 85 and the interior of the boss 85. In this embodiment, the second inlet flow passage 74A is located above the second outlet flow passage 74B. Therefore, the second inlet flow passage 74A and the second outlet flow passage 74B are aligned vertically.

[0051] A first lid portion 88 is fixed to the tip surface 84f of the wall portion 84. The first lid portion 88 covers the first groove portion 81b from the other axial side (-Y). The first heat exchange passage portion 63 is provided between the first lid portion 88 and the first groove portion 81b. That is, the first heat exchange passage portion 63 is provided inside the bearing holder 80. The first lid portion 88 does not overlap with the second inflow passage portion 74A and the second outflow passage portion 74B in the axial direction. Therefore, the second inflow passage portion 74A and the second outflow passage portion 74B are not blocked by the first lid portion 88.

[0052] The first heat exchange flow path portion 63 includes a first arc-shaped flow path portion 63a and a first linear flow path portion 63b. The first arc-shaped flow path portion 63a is a flow path provided in the first arc portion 81ba of the first groove portion 81b. In this embodiment, the first arc-shaped flow path portion 63a extends in a generally arc-like shape centered on the central axis J1 and passing through the other side (-X) in the front-rear direction when viewed from the axial direction. One end of the first arc-shaped flow path portion 63a is located above the central axis J1, and the other end of the first arc-shaped flow path portion 63a is located below the central axis J1. The first linear flow path portion 63b is a flow path provided in the first linear portion 81bb of the first groove portion 81b. The first linear flow path portion 63b extends linearly from the end of the first arc-shaped flow path portion 63a on the other circumferential side (-θ) to one side (+X) in the front-rear direction. Like the first arcuate portion 81ba, the first arcuate flow path portion 63a does not necessarily have an arcuate shape when viewed in the axial direction, but may have a curved shape that surrounds the central axis J1 from the radially outer side. Like the first linear portion 81bb, the first straight flow path portion 63b does not necessarily have to extend linearly, but may have a shape that is at least partially curved. For example, the first heat exchange flow path portion 63 may not have the first straight flow path portion 63b and may be composed only of the first arcuate flow path portion 63a.

[0053] As shown in FIG. 3 , a recess 88a that overlaps with the first groove 81b is provided on a surface of the first cover 88 facing one axial side (+Y). The recess 88a is recessed from the surface of the first cover 88 facing one axial side (+Y) toward the other axial side (−Y). The recess 88a overlaps with the first groove 81b when viewed from the axial direction. The space inside the recess 88a is part of the first heat exchange channel 63. By providing the recess 88a in the first cover 88, the flow path cross section of the first heat exchange channel 63 can be expanded toward one axial side (+Y).

[0054] The first lid 88 is provided with a first inflow passage 64A and a first outflow passage 64B. The first inflow passage 64A has a radial passage 64Aa extending radially outward from the inner surface of the recess 88a and an axial passage 64Ab extending from a radially outer end of the radial passage 64Aa to the other axial side (-Y). Similarly, the first outflow passage 64B has a radial passage 64Ba extending radially outward from the inner surface of the recess 88a and an axial passage 64Bb extending from a radially outer end of the radial passage 64Ba to the other axial side (-Y). The first inflow passage 64A and the first outflow passage 64B are connected to the first heat exchange passage 63 at the radial passages 64Aa and 64Ba, respectively. The first inflow channel portion 64A and the first outflow channel portion 64B open to the other axial side (-Y) at axial channel portions 64Ab and 64Bb, respectively.

[0055] In this embodiment, the first inflow channel portion 64A is located below the central axis J1. The first inflow channel portion 64A is connected to the first straight channel portion 63b of the first heat exchange channel portion 63. On the other hand, the first outflow channel portion 64B is located above the central axis J1. The first outflow channel portion 64B is connected to the first arc-shaped channel portion 63a of the first heat exchange channel portion 63.

[0056] In this embodiment, the connection position of the first heat exchange passage portion 63 with the first outlet passage portion 64B is located on the other circumferential side (-θ) of the end portion on one circumferential side (+θ) of the first heat exchange passage portion 63. In the following description, the portion of the first heat exchange passage portion 63 that extends to one circumferential side (+θ) from the connection position with the first outlet passage portion 64B is referred to as an extension portion 63e. The first heat exchange passage portion 63 of this embodiment has the extension portion 63e that extends to one circumferential side (+θ) from the connection position with the first outlet passage portion 64B.

[0057] The first lid portion 88 is provided with a plurality of ejection ports 88b, 88c. The plurality of ejection ports 88b, 88c penetrate the first lid portion 88 in the axial direction. In this embodiment, the plurality of ejection ports 88b, 88c are aligned along the direction in which the first heat exchange passage portion 63 extends. Of the plurality of ejection ports 88b, 88c, those disposed in the extension portion 63e of the first heat exchange passage portion 63 are referred to as first ejection ports 88b, and those disposed in regions other than the extension portion 63e are referred to as second ejection ports 88c. In this embodiment, the first lid portion 88 is provided with one first ejection port 88b and a plurality of second ejection ports 88c. The first fluid O flowing through the first heat exchange passage portion 63 is ejected to the other axial side (−Y) through the first ejection port 88b and the second ejection port 88c.

[0058] As shown in FIG. 3, a second groove 81c recessed toward the other axial side (-Y) is provided on the first surface 82a of the plate portion 82. That is, the second groove 81c is provided on the surface of the holder main body 81 facing the other axial side (-Y). The second groove 81c has a second arc portion 81ca, a second linear portion 81cb, and a third linear portion 81cc. In this embodiment, the second arc portion 81ca extends in a generally arc shape centered on the central axis J1 and passing toward the other front-rear direction side (-X) when viewed from the axial direction. The second arc portion 81ca of the second groove 81c axially overlaps with the first arc portion 81ba of the first groove 81b (see FIG. 2). The end of the second arc portion 81ca on one circumferential side (+θ) is located above the central axis J1, and the end of the second arc portion 81ca on the other circumferential side (-θ) is located below the central axis J1. The second linear portion 81cb extends linearly from the end of the second arc portion 81ca on the other circumferential side (-θ) toward one front-rear direction side (+X). The second linear portion 81cb of the second groove portion 81c axially overlaps with the first linear portion 81bb of the first groove portion 81b (see FIG. 2). The third linear portion 81cc extends linearly from the end of the second arc portion 81ca on one circumferential side (+θ) toward one front-rear direction side (+X). Note that the second arc portion 81ca does not necessarily have to have an arc-like shape when viewed in the axial direction, but may have a curved shape that extends radially around the central axis J1 from the outside. The second linear portion 81cb and the third linear portion 81cc do not necessarily need to extend linearly, and may have at least a partially curved shape. Furthermore, the second groove portion 81c may not have, for example, either or both of the second linear portion 81cb and the third linear portion 81cc.

[0059] A plurality of second protrusions 81e are provided on the bottom surface of the second groove portion 81c. The plurality of second protrusions 81e protrude from the bottom surface of the second groove portion 81c toward one axial side (+Y). In this embodiment, the second protrusions 81e are plate-shaped. The plurality of second protrusions 81e extend along the extension direction of the second groove portion 81c at their respective locations. That is, the second protrusions 81e or portions of the second protrusions 81e arranged on the second arc portion 81ca are curved along the extension direction of the second arc portion 81ca, while the second protrusions 81e or portions of the second protrusions 81e arranged on the third linear portion 81cc extend substantially linearly along the extension direction of the third linear portion 81cc. In addition, the second protrusions 81e do not necessarily have to extend along the direction in which the second groove portions 81c extend at each location, and at least some of the multiple second protrusions 81e may extend in a direction other than the direction in which the second groove portions 81c extend.

[0060] The second groove 81c has a bottom surface provided with a second inlet flow passage 74A and a second outlet flow passage 74B. The second inlet flow passage 74A is located at the end of the third straight portion 81cc on one side (+X) in the front-rear direction. The second outlet flow passage 74B is located at the end of the second straight portion 81cb on one side (+X) in the front-rear direction.

[0061] A second lid portion 89 is fixed to the second surface 82b of the plate portion 82. The second lid portion 89 covers the second groove portion 81c from one axial side (+Y). A second heat exchange passage portion 73 is provided between the second lid portion 89 and the second groove portion 81c. In other words, the second heat exchange passage portion 73 is provided inside the bearing holder 80.

[0062] The second heat exchange flow path portion 73 includes a second arc-shaped flow path portion 73a, a second linear flow path portion 73b, and a third linear flow path portion 73c. ​​The second arc-shaped flow path portion 73a is a flow path provided in the second arc portion 81ca of the second groove portion 81c. In this embodiment, the second arc-shaped flow path portion 73a extends in a substantially arc shape centered on the central axis J1 and passing through the other side (-X) in the front-rear direction when viewed from the axial direction. One end of the second arc-shaped flow path portion 73a is located above the central axis J1, and the other end of the second arc-shaped flow path portion 73a is located below the central axis J1. The second linear flow path portion 73b is a flow path provided in the second linear portion 81cb of the second groove portion 81c. The second straight flow path portion 73b extends linearly from the end of the second arc-shaped flow path portion 73a on the other circumferential side (-θ) toward one side (+X) in the front-rear direction. The third straight flow path portion 73c is a flow path provided in the third straight flow path portion 81cc of the second groove portion 81c. The third straight flow path portion 73c extends linearly from the end of the second arc-shaped flow path portion 73a on the one circumferential side (+θ) toward one side (+X) in the front-rear direction. Note that, like the second arc-shaped flow path portion 81ca, the second arc-shaped flow path portion 73a does not necessarily have an arc-like shape when viewed in the axial direction, but may have a curved shape that surrounds the central axis J1 from the radially outer side. Like the second straight flow path portion 81cb and the third straight flow path portion 81cc, the second straight flow path portion 73b and the third straight flow path portion 73c do not necessarily have to extend linearly and may have at least a partially curved shape. The second heat exchange passage section 73 may not have, for example, either one or both of the second straight passage section 73b and the third straight passage section 73c.

[0063] In the second heat exchange passage portion 73, the second outlet passage portion 74B is connected to the end of the second straight passage portion 73b on one side (+X) in the front-rear direction, and the second inlet passage portion 74A is connected to the end of the third straight passage portion 73c on one side (+X) in the front-rear direction. That is, the second inlet passage portion 74A is connected to one end of the second heat exchange passage portion 73, and the second outlet passage portion 74B is connected to the other end. The second inlet passage portion 74A and the second outlet passage portion 74B each extend from the second heat exchange passage portion 73 toward the other axial side (-Y).

[0064] As shown in FIGS. 2 and 3 , the first arc-shaped flow path portion 63a and the second arc-shaped flow path portion 73a overlap in the axial direction, and the first straight flow path portion 63b and the second straight flow path portion 73b overlap in the axial direction. That is, the first heat exchange flow path portion 63 and the second heat exchange flow path portion 73 at least partially overlap in the axial direction. A wall portion 81a is provided between the first heat exchange flow path portion 63 and the second heat exchange flow path portion 73. The wall portion 81a is a part of the plate portion 82 and extends along a plane perpendicular to the central axis J1. That is, the bearing holder 80 has the wall portion 81a. The bottom surface of the first groove portion 81b faces the other axial side (−Y) of the wall portion 81a, and the bottom surface of the second groove portion 81c faces the one axial side (+Y) of the wall portion 81a. The wall portion 81 a separates the first heat exchange passage portion 63 from the second heat exchange passage portion 73. Heat exchange occurs between the first fluid O flowing through the first heat exchange passage portion 63 and the second fluid W flowing through the second heat exchange passage portion 73 via the wall portion 81 a.

[0065] The first heat exchange passage portion 63 of this embodiment is provided between the first groove portion 81b and the first lid portion 88 that covers the first groove portion 81b. Similarly, the second heat exchange passage portion 73 of this embodiment is provided between the second groove portion 81c and the second lid portion 89 that covers the second groove portion 81c. Therefore, compared to, for example, forming the hole-shaped first heat exchange passage portion or the second heat exchange passage portion by drilling or the like, it is easier to form the curved first heat exchange passage portion 63 and the second heat exchange passage portion 73. As a result, the first heat exchange passage portion 63 and the second heat exchange passage portion 73 that are long enough to perform heat exchange can be provided in the bearing holder 80 without increasing the size of the bearing holder 80.

[0066] In this embodiment, the wall portion 81a is provided with a first protrusion 81d that protrudes into the first heat exchange channel portion 63. This increases the surface area of ​​the bearing holder 80 that comes into contact with the first fluid O flowing through the first heat exchange channel portion 63, facilitating heat transfer from the first fluid O to the wall portion 81a. Furthermore, the first protrusion 81d generates turbulence in the first fluid O flowing through the first heat exchange channel portion 63, facilitating heat transfer between the first fluid O and the wall portion 81a. Similarly, in this embodiment, the wall portion 81a is provided with a second protrusion 81e that protrudes into the second heat exchange channel portion 73. This generates turbulence in the second fluid W flowing through the second heat exchange channel portion, enabling efficient heat exchange between the wall portion 81a and the second fluid W. This allows one fluid to efficiently cool another fluid. In the present embodiment, the wall portion 81a is provided with both the first protrusion 81d and the second protrusion 81e. However, if the wall portion 81a is provided with at least one of the first protrusion 81d and the second protrusion 81e, heat exchange between the first fluid O and the second fluid W can be performed more efficiently. In the present embodiment, the first protrusion 81d and the second protrusion 81e are plate-shaped. However, the shapes of the first protrusion 81d and the second protrusion 81e are not limited, and for example, the first protrusion 81d and the second protrusion 81e may have other shapes, such as a pin shape.

[0067] In this embodiment, the first protrusion 81 d and the second protrusion 81 e overlap in the axial direction. This facilitates mutual heat conduction between the first protrusion 81 d and the second protrusion 81 e. This allows for more efficient heat exchange between the first fluid O flowing through the first heat exchange passage 63 and the second fluid W flowing through the second heat exchange passage 73.

[0068] 1, the fluid guides 87A and 87B are respectively disposed on one axial side and the other axial side of the stator 30. In this embodiment, the two fluid guides 87A and 87B have a generally annular shape when viewed in the axial direction. The two fluid guides 87A and 87B are assembled to at least one of the first housing portion 6A and the stator core 32. The fluid guides 87A and 87B are made of, for example, a resin material.

[0069] Hereinafter, when distinguishing between the two fluid guides 87A and 87B, the one located on one axial side (+Y) of the stator 30 will be referred to as the first fluid guide 87A, and the other located on the other axial side (-Y) of the stator 30 will be referred to as the second fluid guide 87B.

[0070] The first fluid guide 87A faces the opening of the first hole 32a in the end face on one axial side (+Y) of the stator core 32. The first fluid guide 87A is disposed along the inner surface of the first accommodating portion 6A. A gap is provided between the first fluid guide 87A and the inner surface of the first accommodating portion 6A. The gap between the first fluid guide 87A and the inner surface of the first accommodating portion 6A connects to the first hole 32a. The first fluid guide 87A is located radially outward of the coil end 31a on one axial side (+Y) and faces the coil end 31a in the radial direction. The first fluid guide 87A has multiple holes (not shown). The multiple holes of the first fluid guide 87A guide the first fluid O that flows from the first hole 32a into the gap between the first fluid guide 87A and the inner surface of the first accommodating portion 6A to the coil end 31a.

[0071] The second fluid guide 87B faces the opening of the second hole 32b in the end face on the other axial side (-Y) of the stator core 32. The second fluid guide 87B is arranged along the inner surface of the first accommodating portion 6A. A gap is provided between the second fluid guide 87B and the inner surface of the first accommodating portion 6A. The gap between the second fluid guide 87B and the inner surface of the first accommodating portion 6A connects to the second hole 32b. The second fluid guide 87B is located radially outward of the coil end 31a on the other axial side (-Y) and faces the coil end 31a in the radial direction. The second fluid guide 87B has multiple holes (not shown). The multiple holes of the second fluid guide 87B guide the first fluid O that flows from the second hole 32b into the gap between the second fluid guide 87B and the inner surface of the first accommodating portion 6A to the coil end 31a.

[0072] The shapes of the fluid guides 87A and 87B are not limited to those of the present embodiment as long as they are capable of supplying the first fluid O to the coil end 31 a. The first fluid guide 87A and the second fluid guide 87B may have the same shape or different shapes.

[0073] When the first fluid O is oil, the first fluid O is used not only as a coolant for the rotating electric machine 2 but also as a lubricant for the power transmission mechanism 3. In this case, it is preferable to use an oil equivalent to an automatic transmission fluid (ATF) with a relatively low viscosity as the first fluid O to function as both a lubricant and a coolant. In this case, the first fluid O accumulates in a lower region of the second housing 6B. In the following description, this lower region of the second housing 6B is referred to as a fluid pool P. The first fluid O accumulated in the fluid pool P is scooped up by the operation of the power transmission mechanism 3 and splashes into the second housing 6B. The first fluid O splashed into the second housing 6B is supplied to each gear of the power transmission mechanism 3 in the second housing 6B and applied to the gear tooth surfaces. The first fluid O supplied to the power transmission mechanism 3 and used for lubrication drips into the fluid pool P.

[0074] (First flow path) The first flow path 60 is a circulation path that supplies the first fluid O from the fluid reservoir P to the bearing holder 80, cools it in the bearing holder 80, supplies it to the rotating electric machine 2 to cool the rotating electric machine 2, and then returns it to the fluid reservoir P.

[0075] A pump 8 is provided in the first flow path 60. The pump 8 is fixed to the outer surface of the housing 6. The pump 8 in this embodiment is an electric pump that is driven by electricity. The pump 8 may also be a mechanical pump that operates in conjunction with the driving of the power transmission mechanism 3. The pump 8 pumps the first fluid O in the first flow path 60. The pump 8 may also be fixed to the inner surface of the housing.

[0076] The first flow passage 60 of this embodiment has a plurality of connection flow passage portions 61 , 62 , a first holder internal flow passage portion 66 , a stator cooling flow passage portion 67 , and a supply flow passage portion (supply portion) 65 .

[0077] The plurality of connection flow passages 61, 62 and the supply flow passage 65 are holes provided in the outer peripheral wall 6d of the housing 6, and are provided by drilling holes in the outer peripheral wall 6d, for example.

[0078] The connection flow path portions 61, 62 are flow paths that connect the fluid reservoir P and the bearing holder 80. When the multiple connection flow path portions 61, 62 are to be distinguished from one another, they are referred to as a first connection flow path portion 61 and a second connection flow path portion 62. The first connection flow path portion 61 connects the fluid reservoir P and the intake port of the pump 8. The second connection flow path portion 62 connects the discharge port of the pump 8 and a first holder internal flow path portion 66.

[0079] The first fluid O passing through the first holder internal flow path section 66 is cooled by heat exchange with the second fluid W in the second holder internal flow path section 76. In the first holder internal flow path section 66, the first fluid O flows through the first inflow flow path section 64A, the first heat exchange flow path section 63, and the first outflow flow path section 64B in this order.

[0080] 4 is a cross-sectional view of the drive unit 1 showing the first heat exchange channel portion 63. The first heat exchange channel portion 63 extends along a plane perpendicular to the central axis J1. The first heat exchange channel portion 63 surrounds the bearing 4A from the radial outside. The first fluid O flows through the first heat exchange channel portion 63 toward one circumferential side (+θ). The first fluid O also flows through the first heat exchange channel portion 63 from the lower side to the upper side.

[0081] In this embodiment, the first heat exchange passage portion 63 extends in the circumferential direction about the central axis J1. Furthermore, as shown in Fig. 2, a plurality of ejection ports 88b, 88c are provided in the first lid portion 88 of the bearing holder 80. As shown in Fig. 1, a portion of the first fluid O flowing through the first heat exchange passage portion 63 is ejected from the ejection ports 88b, 88c toward the other axial side (-Y) and supplied to the coil end 31a, cooling the coil end 31a.

[0082] As shown in Fig. 4, the first heat exchange passage portion 63 is provided with an extension portion 63e that extends further toward one circumferential side (+θ) than the first outlet passage portion 64B. At least a portion of the extension portion 63e overlaps with the bus bar 90 in the axial direction. As shown in Fig. 2, the first ejection port 88b is provided in the extension portion 63e. As shown in Fig. 1, a portion of the first fluid O flowing through the first heat exchange passage portion 63 is ejected from the first ejection port 88b toward the other axial side (-Y) and supplied to the bus bar 90, cooling the bus bar 90.

[0083] In the present embodiment, the bus bar 90 is described as being located axially between the motor body 2a and the bearing holder 80. However, the bus bar 90 may be located on one axial side (+Y) of the bearing holder 80. In this case, the first ejection port 88b provided in the bearing holder 80 ejects the first fluid O toward one axial side.

[0084] In the present embodiment, the bearing holder 80 and the bus bar 90 are disposed at a distance from each other in the axial direction. However, the bearing holder 80 may be in contact with the bus bar 90. For example, a portion of the first lid portion 88 may protrude toward the bus bar 90 and be in contact with the bus bar 90. In this case, the bus bar 90 can be cooled without applying the first fluid O to the bus bar 90.

[0085] As shown in FIG. 1 , the first fluid O flowing through the first holder internal flow path 66 flows into the supply flow path 65. The supply flow path 65 in this embodiment supplies the first fluid O to the stator 30. However, the supply flow path 65 may also be a flow path that supplies the first fluid O to the rotor 20. The supply flow path 65 may also branch midway through its path to supply the first fluid O to both the rotor 20 and the stator 30. That is, the supply flow path 65 may be any flow path that supplies the first fluid O to the motor main body 2a. When the supply flow path 65 supplies the first fluid O to the rotor 20, the supply flow path 65 is connected to the hollow portion 22 of the motor shaft 21. In this case, the first fluid O supplied to the hollow portion 22 is guided into the rotor 20 via a through-hole provided in the motor shaft 21 and cools the rotor 20.

[0086] The supply passage 65 connects the first holder inner passage 66 and the stator cooling passage 67. The downstream end of the supply passage 65 opens at the inner circumferential surface of the outer circumferential wall 6d. The downstream end of the supply passage 65 faces the groove 32g of the stator core 32.

[0087] The stator cooling flow path 67 is a flow path that supplies the first fluid O to the coil end 31a through the groove 32g of the stator core 32, the first hole 32a, the second hole 32b, and the inside of the fluid guides 87A and 87B.

[0088] In the stator cooling flow path 67, the grooves 32g allow the first fluid O supplied from the supply flow path 65 to flow in the circumferential direction. In the stator cooling flow path 67, the first holes 32a guide the first fluid O in the grooves 32g toward one axial side (+Y) and supply it to the first fluid guide 87A, and the second holes 32b guide the first fluid O in the grooves 32g toward the other axial side (-Y) and supply it to the second fluid guide 87B. The first fluid O cools the stator core 32 as it flows through the grooves 32g, the first holes 32a, and the second holes 32b.

[0089] The first fluid guide 87A and the second fluid guide 87B supply the first fluid O to the coil end 31 a through a plurality of holes. The first fluid O supplied to the coil end 31 a cools the coil end 31 a. The first fluid O supplied to the coil end 31 a drips from the coil end 31 a, reaches a lower region of the first accommodating portion 6A, and then returns to the fluid pool P inside the second accommodating portion 6B through a flow path not shown.

[0090] (Second Flow Path) The second flow path 70 is a circulation path that supplies the second fluid W cooled by a radiator (not shown) to the drive unit 1 via an external pipe 71, cools the control unit 7 and the first fluid O inside the drive unit 1, and then returns the second fluid W to the radiator again via the external pipe 71. For example, a pump (not shown) that pressurizes the second fluid W is provided in the path of the external pipe 71.

[0091] The second flow path 70 of this embodiment has an external pipe 71 , a control unit cooling flow path portion 72 , a second holder internal flow path portion 76 , and a third connection flow path portion 75 .

[0092] The control unit cooling flow passage portion 72 and the third connection flow passage portion 75 are holes provided in the outer peripheral wall portion 6d of the housing 6, and are provided by drilling holes in the outer peripheral wall portion 6d, for example.

[0093] The control unit cooling flow path 72 connects the external piping 71 and the second holder internal flow path 76. The control unit cooling flow path 72 is provided on the outer peripheral wall 6d directly below the control unit 7. As described above, a portion of the outer peripheral wall 6d is part of the third housing 6C. By providing the control unit cooling flow path 72 on the outer peripheral wall 6d directly below the control unit 7, the control unit 7 is cooled by the second fluid W flowing through the control unit cooling flow path 72. Note that the control unit cooling flow path 72 may be a flow path provided inside the third housing 6C that directly cools the control unit 7.

[0094] The second-holder internal flow path 76 is connected to the control unit cooling flow path 72. The second fluid W flows through the second inflow flow path 74A, the second heat exchange flow path 73, and the second outflow flow path 74B in this order within the second-holder internal flow path 76. The second fluid W passing through the second heat exchange flow path 73 exchanges heat with the first fluid O in the first-holder internal flow path 66, thereby cooling the first fluid O.

[0095] As described above, the first heat exchange passage portion 63 and the second heat exchange passage portion 73 are separated by the wall portion 81a of the bearing holder 80. Therefore, the first fluid O flowing through the first heat exchange passage portion 63 contacts one surface of the wall portion 81a, and the second passage 70 flowing through the second heat exchange passage portion 73 contacts the other surface of the wall portion 81a. According to this embodiment, the bearing holder 80 can exchange heat between the first fluid O flowing through the first passage 60 and the second fluid W flowing through the second passage 70 via the wall portion 81a. This allows the drive unit 1 to be more compact than when a separate heat exchanger is provided in the rotating electric machine 2. In particular, because the bearing holder 80 is disposed near the motor main body 2a, the supply passage portion 65, which supplies the first fluid O cooled by the bearing holder 80 to the motor main body 2a, can be shortened. This reduces pressure loss of the first fluid O in the supply passage portion 65 and makes it easier to prevent the temperature of the first fluid O from increasing midway through the supply passage portion 65. Therefore, the motor main body 2a can be cooled efficiently.

[0096] According to this embodiment, the first heat exchange passage portion 63 is located on the other axial side (−Y) of the wall portion 81a, and the second heat exchange passage portion 73 is located on one axial side (+Y) of the wall portion 81a. That is, one of the first heat exchange passage portion 63 and the second heat exchange passage portion 73 of this embodiment is located on the motor main body 2a side of the wall portion 81a, and the other is located on the opposite side of the wall portion 81a from the motor main body 2a. If both the first heat exchange passage portion 63 and the second heat exchange passage portion 73 were located near the motor main body 2a, the heat from the motor main body 2a would cause the temperatures of both the first fluid O and the second fluid W to rise, which could result in insufficient heat exchange between the first fluid O and the second fluid W. According to this embodiment, by arranging the second heat exchange passage portion 73 farther from the motor main body 2a than the first heat exchange passage portion 63, it is possible to suppress the heat of the motor main body 2a from being transferred to the second fluid W, and it is easier to exchange heat between the first fluid O and the second fluid W. Furthermore, according to this embodiment, the bearing holder 80 is less likely to become large in the radial direction than when the first heat exchange passage portion 63 and the second heat exchange passage portion 73 are arranged radially, and the rotating electric machine 2 can be made smaller in the radial direction.

[0097] In this embodiment, the temperature of the first fluid O flowing through the first heat exchange channel portion 63 before heat exchange is higher than the temperature of the second fluid W flowing through the second heat exchange channel portion 73 before heat exchange. Therefore, in the bearing holder 80, the first fluid O is cooled by the second fluid W. According to this embodiment, the low-temperature first fluid O flows on the motor main body 2a side of the wall portion 81a, and the high-temperature second fluid W flows on the opposite side of the wall portion 81a from the motor main body 2a. This prevents heat from the motor main body 2a from being transferred to the second fluid W, making it easier for the second fluid W to cool the first fluid O and other parts.

[0098] In this embodiment, at least a portion of the first heat exchange channel portion 63 axially overlaps with the second heat exchange channel portion 73. Therefore, the first fluid O flowing through the first heat exchange channel portion 63 and the wall portion 81a are disposed between the second heat exchange channel portion 73 and the motor main body 2a. This prevents heat from the motor main body 2a from being transferred to the second fluid W flowing through the second heat exchange channel portion 73, making it easier for the second fluid W to cool the first fluid O.

[0099] The temperature of the first fluid flowing through the first heat exchange passage portion 63 before heat exchange may be lower than the temperature of the second fluid flowing through the second heat exchange passage portion 73 before heat exchange. In this case, in the bearing holder 80, the second fluid is cooled by the first fluid located on the motor main body 2a side of the wall portion 81a. In this case, by arranging the first heat exchange passage portion 63 on the other axial side (-Y) of the wall portion 81a and the second heat exchange passage portion 73 on one axial side (+Y) of the wall portion 81a, the first fluid can absorb heat generated by the motor main body 2a, and the motor main body 2a can be cooled by the first fluid.

[0100] 5 is a front view of the drive unit 1 showing the second heat exchange passage portion 73. Note that in FIG. 5, some components of the housing 6 (the second lid portion 89 and the cover 6k) are not shown in order to show the second heat exchange passage portion 73.

[0101] As shown in Fig. 5, the second heat exchange passage portion 73 extends along a plane perpendicular to the central axis J1. The second heat exchange passage portion 73 surrounds the bearing 4A and the sensor main body 52 from the radial outside. When viewed from one axial side (+Y), the second fluid W flows through the second heat exchange passage portion 73 toward the other circumferential side (-θ). The second fluid W also flows from the top to the bottom of the second heat exchange passage portion 73.

[0102] According to this embodiment, the second fluid W in the second heat exchange passage portion 73 flows in the opposite direction to the direction in which the first fluid O flows in the first heat exchange passage portion 63. Therefore, a temperature difference between the first fluid O and the second fluid W can be ensured over the entire length of the first heat exchange passage portion 63, and heat can be efficiently exchanged between the first fluid O and the second fluid W in the bearing holder 80.

[0103] In this embodiment, the first heat exchange channel portion 63 and the second heat exchange channel portion 73 both extend in the circumferential direction about the central axis J1. According to this embodiment, the first heat exchange channel portion 63 and the second heat exchange channel portion 73 can be formed in the bearing holder 80 so as to surround the bearing 4A. This makes it possible to lengthen the channel lengths of the first heat exchange channel portion 63 and the second heat exchange channel portion 73 formed in the bearing holder 80 while preventing the bearing holder 80 from becoming larger, thereby enabling efficient heat exchange between the first fluid O and the second fluid W.

[0104] According to this embodiment, the second heat exchange passage portion 73 overlaps with the coil end 31 a in the axial direction, similar to the first heat exchange passage portion 63. Therefore, the heat generated by the coil end 31 a can be absorbed by the second fluid W flowing through the second heat exchange passage portion 73, thereby cooling the coil end 31 a. In this embodiment, both the first heat exchange passage portion 63 and the second heat exchange passage portion 73 overlap with the coil end 31 a in the axial direction. Therefore, the coil end 31 a can be cooled by the first fluid O and the second fluid W. However, if at least one of the first heat exchange passage portion 63 and the second heat exchange passage portion 73 overlaps with the coil end 31 a in the axial direction, the coil end 31 a can be cooled more effectively.

[0105] According to this embodiment, the second heat exchange channel portion 73 overlaps with the bus bar 90 in the axial direction, similar to the first heat exchange channel portion 63. Therefore, the heat generated by the bus bar 90 can be absorbed by the second fluid W flowing through the second heat exchange channel portion 73, thereby cooling the bus bar 90. In this embodiment, both the first heat exchange channel portion 63 and the second heat exchange channel portion 73 overlap with the bus bar 90 in the axial direction. Therefore, the bus bar 90 can be cooled by the first fluid O and the second fluid W. However, if at least one of the first heat exchange channel portion 63 and the second heat exchange channel portion 73 overlaps with the bus bar 90 in the axial direction, the bus bar 90 can be cooled more effectively.

[0106] In this embodiment, the second heat exchange passage portion 73 is disposed in an arc shape that surrounds the central axis J1 and the sensor main body 52 of the rotational position sensor 50 from the radially outer side. According to this embodiment, the sensor main body 52 is disposed radially inward of the second heat exchange passage portion 73. This allows the sensor main body 52 to be disposed in a radially inner region of the second heat exchange passage portion 73, thereby enabling the rotary electric machine 2 to be miniaturized. Here, "arc-shaped" does not necessarily mean a shape that includes an arc-shaped portion, but also means a shape that extends to surround the central axis J1 and the sensor main body 52 as viewed in the axial direction. For example, the second heat exchange passage portion 73 may have a shape that connects multiple straight portions and surrounds the central axis J1 and the sensor main body 52 as a whole.

[0107] 5, multiple electric wires 53 extend radially outward from the sensor main body 52. ​​That is, the rotational position sensor 50 has multiple electric wires 53. The number of electric wires 53 of the rotational position sensor 50 is not limited. In this embodiment, the multiple electric wires 53 extend from the sensor main body 52 to one side (+X) in the front-rear direction. Although not shown, the electric wires 53 extend further upward and are led into the third housing portion 6C and connected to the control unit 7. The electric wires 53 connect the sensor main body 52 and the control unit 7. The electric wires 53 supply power from the control unit 7 to the sensor main body 52. ​​The electric wires 53 output the result of detection of the rotation angle of the rotor 20 by the rotational position sensor 50 to the control unit 7.

[0108] According to this embodiment, the electric wire 53 extends radially outward from the sensor main body 52. ​​Furthermore, the electric wire 53 is located between the second straight flow path portion 73b and the third straight flow path portion 73c of the second heat exchange flow path portion 73 in the up-down direction. Therefore, the electric wire 53 overlaps with the second heat exchange flow path portion 73 in the circumferential direction. According to this embodiment, the region in the circumferential direction where the second heat exchange flow path portion 73 is not provided can be used as an arrangement region for the electric wire 53, and the rotating electric machine 2 can be made smaller.

[0109] 1 , the second fluid W flowing through the second holder internal flow path portion 76 flows into the third connection flow path portion 75. The third connection flow path portion 75 connects the second holder internal flow path portion 76 and the external piping 71. The third connection flow path portion 75 opens, for example, at the outer peripheral surface of the outer peripheral wall portion 6d and is connected to the external piping 71. The second fluid W flows through the external piping 71, is cooled by the radiator, and then flows again into the control unit cooling flow path portion 72.

[0110] The second flow path 70 may further include a flow path portion for cooling the motor main body 2a downstream of the third connecting flow path portion 75. In this case, the flow path portion provided downstream of the third connecting flow path portion 75 may be, for example, a flow path portion provided in a cylindrical water jacket surrounding the stator core 32, or may be a flow path portion that guides the second fluid W to the hollow portion 22 of the motor shaft 21. The shape of the flow path portion is not particularly limited as long as it can cool the motor main body 2a.

[0111] Next, a description will be given of modified bearing holders 180 and 280 that can be employed in the above-described embodiment. In the following description of each modified example, the same components as those in the embodiment already described will be assigned the same reference numerals, and the description thereof will be omitted.

[0112] 6 is a cross-sectional view of a drive unit 1 having a bearing holder 180 of Modification 1. The bearing holder 180 of this modification differs from the above-described embodiment in the arrangement of the first heat exchange passage portion 163, the second heat exchange passage portion 173, and the wall portion 181 a.

[0113] Similar to the above-described embodiment, the bearing holder 180 of this modified example is provided with a first heat exchange channel portion 163 and a second heat exchange channel portion 173. A first fluid O flows through the first heat exchange channel portion 163, and a second fluid W flows through the second heat exchange channel portion 173. The bearing holder 180 is also provided with a wall portion 181a that separates the first heat exchange channel portion 163 and the second heat exchange channel portion 173. Heat exchange occurs between the first fluid O flowing through the first heat exchange channel portion 163 and the second fluid W flowing through the second heat exchange channel portion 173 via the wall portion 181a.

[0114] In this modification, the first heat exchange passage portion 163 is located radially inward relative to the wall portion 181a, and the second heat exchange passage portion 173 is located radially outward relative to the wall portion 181a. According to this modification, the bearing holder 180 can be made smaller in the axial direction than when the first heat exchange passage portion 163 and the second heat exchange passage portion 173 are located on opposite axial sides of the wall portion 181a, and an increase in the axial size of the rotating electric machine 2 can be suppressed.

[0115] In this modified example, the temperature of the first fluid O flowing through the first heat exchange channel portion 163 is higher than the temperature of the second fluid W flowing through the second heat exchange channel portion 173. Therefore, in the bearing holder 180, the first fluid O is cooled by the second fluid W. In this modified example, by arranging the second heat exchange channel portion 173 radially outward of the first heat exchange channel portion 163, it is easy to make the path length of the second heat exchange channel portion 173 longer than the path length of the first heat exchange channel portion 163. Therefore, it is easy to cool the first fluid O by the second fluid W.

[0116] In this modified example, at least a portion of the first heat exchange passage portion 163 radially overlaps with the second heat exchange passage portion 173. This allows efficient heat exchange between the first fluid O flowing through the first heat exchange passage portion 163 and the second fluid W flowing through the second heat exchange passage portion 173, while also enabling the bearing holder 180 to be made smaller overall.

[0117] 7 is a cross-sectional view of the drive unit 1 having a bearing holder 280 of Modification 2. The bearing holder 280 of this modification has a different structure of the first heat exchange channel portion 263 compared to the above-described embodiment.

[0118] Similar to the above-described embodiment, the bearing holder 280 is provided with a first holder internal flow path 266 and a second holder internal flow path 76 (not shown in FIG. 7 ). The first holder internal flow path 266 has a first inflow flow path 64A, a first heat exchange flow path 263, and a first outflow flow path (outflow flow path) 264B. The first fluid O flows through the first holder internal flow path 266 in the following order: the first inflow flow path 64A, the first heat exchange flow path 263, and the first outflow flow path 264B. The first fluid O flowing out of the first outflow flow path 264B is supplied to the motor main body 2a via the supply flow path 65 shown in FIG. 1 .

[0119] As shown in FIG. 7 , the first heat exchange channel portion 263 of this modification does not have the extension portion 63e (see FIG. 4 ) as compared to the above-described embodiment. The length of the first heat exchange channel portion 263 is shorter than when the extension portion 63e is included as in the above-described embodiment. In this modification, the first outlet channel portion 264B is connected to the end of the first heat exchange channel portion 263. According to this modification, when the first fluid O flowing through the first heat exchange channel portion 263 flows into the first outlet channel portion 264B, the pressure loss of the first fluid O flowing through the first holder channel portion 266 can be reduced compared to when the extension portion 63e (see FIG. 4 ) is included. Therefore, the power consumption of the pump 8 that pumps the first fluid O can be reduced.

[0120] Although various embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in each embodiment and modification are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

[0121] For example, in the above-described embodiment, the first inlet flow passage, the second inlet flow passage, the first outlet flow passage, and the second outlet flow passage are provided in the bearing holder. However, these flow passages may be provided inside a pipe that is a separate member from the bearing holder, or may be provided inside the first housing.

[0122] In the above-described embodiment, the first heat exchange passage portion and the second heat exchange passage portion are respectively provided between the groove portion and the lid portion that covers the groove portion. However, the first heat exchange passage portion and the second heat exchange passage portion may be holes provided in the bearing holder.

[0123] Furthermore, in the above-described embodiment, the first and second heat exchange passages are provided in the bearing holder located on one axial side of the motor body. However, the first and second heat exchange passages may be provided in the bearing holder (i.e., the bottom wall) located on the other axial side of the motor body.

[0124] In the above embodiment, the case where the cover, which is a separate member from the bearing holder, is provided on one axial side of the bearing holder has been described. However, the bearing holder and the cover may be an integrated member.

[0125] In the above embodiment, the first arc-shaped flow path portion of the first heat exchange flow path portion and the second arc-shaped flow path portion of the second heat exchange flow path portion both pass through the other side (-X) of the central axis in the front-rear direction. However, either or both of the first arc-shaped flow path portion and the second arc-shaped flow path portion may be arc-shaped and pass through one side (+X) of the central axis in the front-rear direction.

[0126] The arrangements of the first and second heat exchange passage sections in the above-described embodiment and its modified examples are merely examples. For example, the first and second heat exchange passage sections may be arranged at an angle around the central axis relative to the arrangements shown in Figures 4 to 7.

[0127] In the above-described embodiment and its modified examples, the first heat exchange passage portion and the second heat exchange passage portion overlap only in either the axial direction or the radial direction. However, the first heat exchange passage portion and the second heat exchange passage portion may have both an axially overlapping portion and a radially overlapping portion.

[0128] DESCRIPTION OF SYMBOLS 1... drive device, 2... rotating electric machine, 2a... motor main body, 3... power transmission mechanism, 4A, 4B... bearings, 6A... first housing (housing), 7... control unit, 20... rotor, 30... stator, 31... coil, 31a... coil end, 32g... groove, 50... rotational position sensor, 52... sensor main body, 53... electric wire, 60... first flow path, 63, 163, 263... first heat exchange flow path, 64 B, 264B...first outlet flow path portion (outlet flow path portion), 65...supply flow path portion (supply portion), 70...second flow path, 73, 173...second heat exchange flow path portion, 80, 180, 280...bearing holder, 81...holder main body portion, 81a, 181a...wall portion, 81b...first groove portion (groove portion), 81d...first protrusion portion, 81e...second protrusion portion, 88...first lid portion (lid portion), 90...bus bar, J1...central axis line

Claims

1. A rotating electric machine comprising: a rotor rotatable about a central axis; a stator radially opposed to the rotor; a housing portion that houses the rotor and the stator; and a first flow path and a second flow path that are independent of each other, wherein the housing portion has a bearing holder located on one axial side of the stator and supporting the rotor via a bearing, the first flow path having a first heat exchange flow path portion provided inside the bearing holder, the second flow path having a second heat exchange flow path portion provided inside the bearing holder, and the bearing holder having a wall portion that separates the first heat exchange flow path portion and the second heat exchange flow path portion.

2. A rotating electric machine according to claim 1, wherein the first heat exchange passage portion is located on the other axial side of the wall portion, and the second heat exchange passage portion is located on one axial side of the wall portion.

3. A rotating electric machine according to claim 2, wherein at least a portion of the first heat exchange passage portion overlaps with the second heat exchange passage portion in the axial direction.

4. A rotating electric machine according to claim 1, wherein the first heat exchange passage portion is located radially inward relative to the wall portion, and the second heat exchange passage portion is located radially outward relative to the wall portion.

5. A rotating electric machine according to claim 4, wherein at least a portion of the first heat exchange passage portion overlaps with the second heat exchange passage portion in the radial direction.

6. A rotating electric machine according to any one of claims 1 to 5, wherein the stator has coil ends located on one axial side and the other axial side, the first heat exchange passage portion and the second heat exchange passage portion extend in a circumferential direction centered on the central axis, and at least one of the first heat exchange passage portion and the second heat exchange passage portion overlaps with the coil ends in the axial direction.

7. A rotating electric machine according to any one of claims 1 to 6, wherein the fluid inside the second heat exchange passage portion flows in a direction opposite to the direction in which the fluid inside the first heat exchange passage portion flows.

8. A rotating electric machine according to any one of claims 1 to 7, further comprising: a bus bar located on one axial side of the stator and connecting the stator and the control unit, wherein at least one of the first heat exchange flow path portion and the second heat exchange flow path portion overlaps with the bus bar in the axial direction.

9. A rotating electric machine as claimed in any one of claims 1 to 8, wherein the first flow path comprises: a supply section that supplies fluid to a motor main body consisting of the stator and the rotor; and an outlet flow path section that connects the first heat exchange flow path section and the supply section, and the outlet flow path section is connected to an end of the first heat exchange flow path section.

10. A rotating electric machine as claimed in any one of claims 1 to 9, comprising a rotational position sensor that detects the rotational position of the rotor, the rotational position sensor comprising: a sensor body supported by the bearing holder; and an electric wire extending radially outward from the sensor body, the second heat exchange flow path portion being arranged in an arc that surrounds the central axis and the sensor body from the radially outward side, and the electric wire overlapping the second heat exchange flow path portion in the circumferential direction.

11. A rotating electric machine according to any one of claims 1 to 10, wherein the bearing holder has a holder main body and a lid fixed to the holder main body, and the first heat exchange flow path is provided between a groove provided on a surface of the holder main body facing the other axial side and the lid covering the groove.

12. The rotating electric machine according to claim 11, wherein the thermal conductivity of the material forming the lid is lower than the thermal conductivity of the material forming the holder body.

13. A rotating electric machine according to any one of claims 1 to 12, wherein the wall portion is provided with at least one of a first protrusion protruding into the inside of the first heat exchange flow path portion and a second protrusion protruding into the inside of the second heat exchange flow path portion.

14. A drive device comprising: a rotating electric machine according to any one of claims 1 to 13; and a power transmission mechanism connected to the rotor.

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