motor unit

Abstract

One aspect of the motor unit of the present invention includes: a motor having a rotor and a stator, the rotor having a motor shaft rotating about a motor axis, the stator being located radially outward of the rotor; a first bearing supporting the motor shaft; a stator cage holding the stator; and a housing body housing the motor and the stator cage. The stator cage has: a cylindrical portion surrounding the stator radially outward; and a base plate extending radially inward from an axial end of the cylindrical portion. The housing body has opposing inner circumferential surfaces that are radially opposed to the outer circumferential surface of the cylindrical portion. A passage for refrigerant flow is provided between the outer circumferential surface of the cylindrical portion and the opposing inner circumferential surface. The base plate holds the first bearing.

Description

Technical Field

[0001] This invention relates to a motor unit.

[0002] This application asserts priority based on Japanese Patent Application No. 2020-026149, filed on February 19, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] In recent years, the development of drive systems for electric vehicles has been extensive. Patent Document 1 describes a motor-type power unit (motor unit) that achieves miniaturization by passing the output shaft through the interior of a hollow shaft.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-121549 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In the existing structure, the bearings that support both the hollow shaft and the output shaft extending from the hollow shaft are held in the housing. Therefore, the bearing holding structure implemented by the housing becomes complex, as does the assembly process.

[0009] One aspect of the object of the present invention is to provide a motor unit that simplifies the assembly process.

[0010] Technical solutions adopted to solve technical problems

[0011] One aspect of the motor unit of the present invention includes: a motor having a rotor and a stator, the rotor having a motor shaft rotating about a motor axis, the stator being located radially outward of the rotor; a first bearing supporting the motor shaft; a stator cage holding the stator; and a housing body housing the motor and the stator cage. The stator cage has: a cylindrical portion surrounding the stator radially outward; and a base plate extending radially inward from an axial end of the cylindrical portion. The housing body has opposing inner circumferential surfaces that are radially opposed to the outer circumferential surface of the cylindrical portion. A passage for refrigerant flow is provided between the outer circumferential surface of the cylindrical portion and the opposing inner circumferential surface. The base plate holds the first bearing.

[0012] Invention Effects

[0013] According to one aspect of the present invention, a motor unit that simplifies the assembly process is provided. Attached Figure Description

[0014] Figure 1 This is a conceptual diagram of a motor unit according to one implementation method.

[0015] Figure 2 This is a perspective view of a motor unit according to one embodiment.

[0016] Figure 3 This is an exploded perspective view of the shaft holding part of a motor unit according to one embodiment.

[0017] Figure 4 This is a schematic diagram of the oil pump of a motor unit according to one embodiment. Detailed Implementation

[0018] Hereinafter, a motor unit 10 according to one embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, the scope of the present invention is not limited to the following embodiment, but can be arbitrarily modified within the scope of the technical concept of the present invention. Additionally, in the following drawings, for ease of understanding of each structure, the scale, quantity, etc., of each structure may sometimes differ from the actual structure.

[0019] Figure 1 This is a conceptual diagram of motor unit 10. Figure 2 This is a 3D view of motor unit 10.

[0020] In the following description, the direction of gravity is defined based on the positional relationship of the motor unit 10 installed in a vehicle located on a horizontal road surface. Furthermore, in the accompanying drawings, the XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system.

[0021] In this embodiment, the Z-axis direction represents the vertical direction (i.e., the up-down direction), the +Z direction is the upper side (the side opposite to the direction of gravity), and the -Z direction is the lower side (the direction of gravity). Therefore, in this specification, the term "upper side" simply refers to the upper side in the direction of gravity. Furthermore, the X-axis direction is orthogonal to the Z-axis direction and represents the front-to-back direction of the vehicle on which the motor unit 10 is mounted; the +X direction is the front of the vehicle, and the -X direction is the rear of the vehicle. The Y-axis direction is orthogonal to both the X-axis and Z-axis directions and represents the width direction (left-to-right direction) of the vehicle; the +Y direction is the left side of the vehicle, and the -Y direction is the right side of the vehicle.

[0022] In the following description, unless otherwise specified, the direction parallel to the motor axis J1 of motor 1 (the direction parallel to the Y-axis) will be simply referred to as "axial". In addition, the direction on the +Y side of the axial direction will be referred to as the other side of the axial direction, and the -Y side will be referred to as one side of the axial direction. Furthermore, the radial direction centered on the motor axis J1 will be simply referred to as "radial", and the circumferential direction centered on the motor axis J1, that is, the direction around the axis J1, will be simply referred to as "circumferential".

[0023] In addition, the motor shaft J1 and the secondary shaft shaft J3, which will be described later, are imaginary shafts that do not actually exist.

[0024] The motor unit 10 is installed in the vehicle and causes the vehicle to move forward or backward by rotating the wheels H. The motor unit 10 is installed, for example, in an electric vehicle (EV). In addition, the motor unit 10 can be installed in any vehicle that uses a motor as its power source, such as a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHV).

[0025] like Figure 1 As shown, the motor unit 10 includes a motor 1, a gear section 5, an inverter 8, a housing 6 for housing the motor 1, the gear section 5 and the inverter 8, a shaft retainer 80 for retaining the shaft within the housing 6, a stator retainer 40 for retaining the stator 35 of the motor 1 within the housing 6, and an oil 0.

[0026] (shell)

[0027] The housing 6 is, for example, made of die-cast aluminum. The housing 6 includes: a housing body 60; a sealing member 67 located on the other axial side (+Y side) of the housing body 60; an inverter cover 68 located on the upper side of the housing body 60; and a bottom cover member 69 located on the lower side of the housing body 60. That is, the motor unit 10 has a housing body 60, a sealing member 67, an inverter cover 68, and a bottom cover member 69. The housing 6 is constructed by fastening the housing body 60, the sealing member 67, the inverter cover 68, and the bottom cover member 69 together.

[0028] The main body 60 is provided with a drive unit storage space 61, an inverter storage space 62, and an oil storage space 63. The inverter storage space 62 is arranged on the upper side of the drive unit storage space 61, and the oil storage space 63 is arranged on the lower side.

[0029] The drive unit storage space 61 is an integrated space that houses the motor 1, gear unit 5, shaft retainer 80, stator cage 40, and oil 0. Furthermore, the inverter storage space 62 houses the inverter 8. The oil storage space 63 stores the oil 0 that circulates within the drive unit storage space 61. Thus, the housing body 60 houses the motor 1, gear unit 5, shaft retainer 80, stator cage 40, inverter 8, and oil 0 within each of these spaces.

[0030] A connecting hole 65, which connects to an oil storage space 63, is provided on the lower wall of the drive body storage space 61. Oil O in the lower region of the drive body storage space 61 flows into the oil storage space 63 through the connecting hole 65. Oil O accumulates in the lower region of the drive body storage space 61 and the oil storage space 63.

[0031] Oil O circulates in oil passage 90 located within housing 6. Oil O functions as lubricant for the gear section 5 and also as cooling oil for the motor 1. Ideally, the same type of oil as low-viscosity automatic transmission fluid (ATF) should be used as oil O.

[0032] A portion of the gear ring 51 of the gear section 5 (described later) is immersed in oil O accumulated in the lower region of the drive body housing space 61. The oil O is lifted by the movement of the gear ring 51 and diffuses into the drive body housing space 61. The oil O diffused into the drive body housing space 61 is supplied to each gear of the gear section 5 within the drive body housing space 61, ensuring that the oil O covers the tooth surfaces of the gears. The oil O supplied to the gear section 5 for lubrication drips down and is collected back into the lower region of the drive body housing space 61.

[0033] The housing body 60 has: a first opening 61a that exposes the drive unit housing space 61 to the other side (+Y side) axially; a second opening 62a that exposes the inverter housing space 62 to the upper side; and a third opening 63a that exposes the oil storage space 63 to the lower side. The first opening 61a is covered by a sealing member 67. The second opening 62a is covered by an inverter cover 68. The third opening 63a is covered by a bottom cover member 69.

[0034] The housing body 60 includes: a cylindrical portion 60a centered on a motor axis J1; a bottom 60b covering one axial side of the cylindrical portion 60a; an expansion portion 60c expanding radially from an opening on the other axial side of the cylindrical portion 60a; a box-shaped portion 60d disposed on the upper side of the cylindrical portion 60a; and a storage wall portion 60e located on the lower side of the cylindrical portion 60a. The box-shaped portion 60d surrounds the inverter housing space 62. The box-shaped portion 60d has a second opening 62a. The storage wall portion 60e surrounds the oil storage space 63. The storage wall portion 60e has a third opening 63a.

[0035] A cylindrical portion 60a surrounds the motor 1 radially outward. A bottom portion 60b is located on one axial side (-Y side) of the motor 1. The bottom portion 60b has a bearing retainer 60ba that holds a ball bearing 71. The bottom portion 60b supports the output shaft 55 via the ball bearing 71. Furthermore, the bottom portion 60b supports an oil pump 96.

[0036] The expansion portion 60c is axially opposed to the sealing member 67. The expansion portion 60c has: a protrusion 60ca extending from the opening of the cylindrical portion 60a along a plane orthogonal to the axial direction; and an outer edge 60cb extending from the protrusion 60ca to the other axial side (+Y side). The sealing member 67 is secured to the outer edge 60cb using fastening members such as bolts.

[0037] The sealing member 67 covers the first opening 61a. The sealing member 67, the cylindrical portion 60a, the bottom 60b, and the expansion portion 60c of the housing body 60 surround the drive body receiving space 61. Therefore, by detaching the sealing member 67 from the housing body 60, the drive body receiving space 61 is exposed to the other axial side. The sealing member 67 is concave in shape, opening towards one axial side (-Y side). The sealing member 67 supports the secondary shaft 13 (described later) via ball bearings 79. Furthermore, the sealing member 67 supports the gear housing 52 (described later) and the gear ring 51 (described later) for rotation via tapered roller bearings 77.

[0038] According to this embodiment, the first opening 61a of the housing body 60 exposes the drive unit storage space 61, which houses the motor 1, gear 5, shaft retainer 80, and stator retainer 40, to the other axial side (+Y side). The motor 1, gear 5, shaft retainer 80, and stator retainer 40 are inserted into the interior of the housing body 60 through the first opening 61a.

[0039] The assembly process of the motor unit 10 is performed by sequentially installing the motor 1 and gear unit 5 inside the housing body 60. Generally, the orientation of the housing body 60 is changed by aligning the mounting directions of each component. However, when the housing body 60 is heavy, changing the orientation of the housing body 60 will prolong the assembly process time.

[0040] According to this embodiment, the motor 1, gear 5, shaft retainer 80 and stator retainer 40 can be mounted from one direction relative to the housing body 60, thereby simplifying the assembly process and reducing the assembly cost.

[0041] Furthermore, according to this embodiment, the housing body 60 has a bottom 60b on one axial side (-Y side) of the motor 1 that seals the drive unit storage space 61. Therefore, the bottom 60b can support components (such as the output shaft 55) stored in the drive unit storage space 61 from the other axial side (+Y side), improving installation accuracy and simplifying the installation process. Moreover, since the bottom 60b is part of the housing body 60, one axial side of the drive unit storage space 61 is pre-sealed. Therefore, compared to the case where the drive unit storage space 61 is open on both axial sides, the number of components can be reduced, simplifying the assembly process.

[0042] The box-shaped portion 60d is box-shaped, enclosing the inverter 8. The box-shaped portion 60d opens upwards, forming a second opening 62a. The box-shaped portion 60d and the inverter housing 68 form the wall of the inverter housing space 62. The box-shaped portion 60d is connected to the upper side of the cylindrical portion 60a. A portion of the box-shaped portion 60d is formed by a part of the cylindrical portion 60a and a part of the expansion portion 60c.

[0043] The box-shaped portion 60d has a bottom (partition wall, second wall) 60da, a side wall portion 60db (partition wall, first partition wall), and other side wall portions. The bottom 60da is located radially between the motor 1 and the inverter 8 along the motor axis J1, and the side wall portion 60db is located on the other side of the inverter 8 along the axial direction and between the inverter 8 and the gear portion 5. The bottom 60da is part of the cylindrical portion 60a and is opposite to the second opening in the vertical direction. The side wall portion 60db is part of the expansion portion 60c and extends upward from the bottom 60da. The bottom 60da and the side wall portion 60db function as partitions 66 that divide the drive unit housing space 61 and the inverter housing space 62. Furthermore, a through hole 60h is provided in the side wall portion 60db. The through hole 60h communicates the drive unit housing space 61 and the inverter housing space 62. As described later, the busbar 9 passes through the through hole 60h.

[0044] According to this embodiment, the housing body 60 has a partition 66 that divides the drive unit storage space 61 and the inverter storage space 62. That is, according to this embodiment, the components for storing the motor 1 and gear unit 5 and the components for storing the inverter 8 are constituted by a single component (the housing body 60). Therefore, the overall rigidity of the housing body 60 can be improved, and the vibration suppression effect can be enhanced. As a result, the transmission of vibrations caused by the driving of the motor 1 and gear unit 5 to the inverter 8 can be suppressed, and the load on the inverter 8 can be reduced.

[0045] The inverter housing 68 is fixed to the box-shaped portion 60d. The inverter housing 68 has a top plate portion 68a extending along a horizontal plane. The inverter 8 is fixed to the back side of the top plate portion 68a (i.e., the side facing the inside of the inverter housing space 62). Thus, the inverter housing 68 supports the inverter 8.

[0046] According to this embodiment, the inverter 8 is fixed to an inverter cover 68 that can be detached from the housing body 60. Therefore, during maintenance of the motor unit 10, such as routine inspections and parts replacement, the inverter 8 can be easily detached from the motor unit 10 by releasing the fastening of the inverter cover 68 to the housing body 60. This process can also be performed while the motor unit 10 is installed in the vehicle, improving the maintainability of the inverter 8.

[0047] Alternatively, a refrigerant flow path for cooling the inverter 8 can be provided in the top plate portion 68a. In this case, the refrigerant flow path is provided in the inverter cover 68, which is a different component from the housing body 60 that contacts the motor 1. According to this embodiment, since the heat from the motor 1 is not easily transferred to the refrigerant, the temperature of the inverter 8 can be suppressed to be lower than the temperature of the motor. Furthermore, the flow path provided in the top plate portion 68a can also be connected to the passage portion (recess 44) described later. In this case, the refrigerant used to cool the inverter 8 can be shared with the refrigerant used to cool the motor 1.

[0048] (motor)

[0049] Motor 1 is an electric generator that functions as both an electric motor and a generator. Motor 1 primarily functions as an electric motor to drive the vehicle, and during regeneration, it functions as a generator. In this embodiment, motor 1 is a three-phase AC motor.

[0050] Motor 1 is connected to inverter 8. Inverter 8 converts the direct current supplied from the battery (not shown) into alternating current and supplies it to motor 1. The rotational speeds of motor 1 are controlled by controlling inverter 8.

[0051] Motor 1 has a rotor 31 and a stator 35 located radially outside the rotor 31. The rotor 31 is rotatable about the motor axis J1. The stator 35 is annular. The stator 35 surrounds the rotor 31 radially outside the motor axis J1.

[0052] The rotor 31 has a motor shaft 32, a rotor core 31a, and a rotor magnet (not shown) held in the rotor core 31a. That is, the motor 1 has a motor shaft 32.

[0053] The rotor 31 (i.e., the motor shaft 32, the rotor core 31a, and the rotor magnets) rotates around the motor axis J1. The torque of the rotor 31 is transmitted to the gear section 5. The rotor core 31a is constructed by stacking silicon steel sheets. The rotor core 31a is a cylinder extending axially. Multiple rotor magnets are fixed in the rotor core 31a. The multiple rotor magnets are arranged circumferentially with alternating magnetic poles.

[0054] The motor shaft 32 extends along the motor axis J1, which extends in the width direction of the vehicle. The motor shaft 32 is a hollow shaft that opens to both axial sides of the motor axis J1. That is, the motor shaft 32 has a hollow portion 32h that opens to both axial sides.

[0055] The motor shaft 32 has: a first end 32A, which is located on the other side of the axial direction (+Y side); and a second end 32B, which is located on one side of the axial direction (-Y side).

[0056] The first end 32A of the motor shaft 32 is supported by a ball bearing 73 and is rotatable. A recessed spline 32b is provided in the opening of the hollow portion 32h of the first end 32A. The motor shaft 32 is connected to the input shaft 11 of the gear section 5 at the recessed spline 32b of the first end 32A.

[0057] The second end 32B of the motor shaft 32 is supported by a ball bearing 72 and is rotatable. A resolver rotor 3a is fixed to the outer circumferential surface of the second end 32B. The resolver rotor 3a rotates together with the motor shaft 32 about the motor axis J1. The resolver rotor 3a is located further axially (towards the -Y side) than the ball bearing 72 supporting the second end 32B.

[0058] The stator 35 includes: an annular stator core 35a; a coil 35b wound around the stator core 35a; and an insulating member (not shown) sandwiched between the stator core 35a and the coil 35b. The stator core 35a has a plurality of pole teeth protruding radially inward toward the motor axis J1. Coil wire is wound around the pole teeth. The coil wire wound around the pole teeth constitutes the coil 35b.

[0059] Coil 35b has coil edge ends 35c that protrude axially from the stator core 35a to both sides. One coil edge end 35c protrudes axially from the end face on the other side of the stator core 35a, and the other coil edge end 35c protrudes axially from the end face on one side of the stator core 35a. Connecting coil wires 35d extend from the coil edge ends 35c on the other side of the axial direction. Connecting coil wires 35d have twisted coil wires and an insulating tube covering the outer periphery of the coil wires. The motor 1 of this embodiment is a three-phase AC motor, and therefore has three corresponding connecting coil wires 35d. The connecting coil wires 35d are connected to the inverter 8 via bus 9.

[0060] <Gear Section>

[0061] The gear unit 5 is connected to the other side (+Y side) of the motor 1 along its axial direction. The gear unit 5 transmits power from the motor 1 and outputs it from the output shaft 55. The gear unit 5 contains multiple mechanisms that carry out the power transmission between the drive source and the driven device.

[0062] The gear unit 5 includes an input shaft 11, an input gear 21, a countershaft 13, a countershaft gear 23, a drive gear 24, a gear ring 51, an output shaft 55, and a differential device 50.

[0063] Each gear and shaft of the gear unit 5 is rotatable about either the motor axis J1 or the secondary shaft axis J3. In this embodiment, the motor axis J1 and the secondary shaft axis J3 extend parallel to each other. Furthermore, the motor axis J1 and the secondary shaft axis J3 are parallel to the width direction of the vehicle. In the following description, axial direction refers to the axial direction of the motor axis J1. That is, the axial direction in this specification refers to the direction parallel to the motor axis J1, i.e., the width direction of the vehicle.

[0064] The input shaft 11 extends along the motor axis J1. The input shaft 11 is a hollow shaft that opens to both sides of the motor axis J1. That is, the input shaft 11 has a hollow portion 11h that opens to both sides of the motor axis.

[0065] The input shaft 11 has: a first end 11A located on the other side of the axial direction (+Y side); and a second end 11B located on one side of the axial direction (-Y side). The input shaft 11 is supported by a ball bearing 74 between the first end 11A and the second end 11B to enable rotation.

[0066] A male spline 11a is provided on the outer peripheral surface of the second end 11B of the input shaft 11. The male spline 11a is fitted into the female spline 32b of the motor shaft 32. Thus, the first end 32A of the motor shaft 32 is connected to the second end 11B of the input shaft 11. That is, the input shaft 11 is axially connected to the motor shaft 32. Furthermore, the hollow portion 32h of the motor shaft 32 is in communication with the hollow portion 11h of the input shaft 11. The input shaft 11 rotates by transmitting the rotation of the motor 1.

[0067] An input gear 21 is disposed on the outer peripheral surface of the first end 11A of the input shaft 11. The input gear 21 rotates together with the input shaft 11 about the motor axis J1. In this embodiment, the input gear 21 and the input shaft 11 are a single component. However, the input gear 21 may also be a different component mounted on the outer peripheral surface of the input shaft 11.

[0068] The secondary shaft 13 extends along the secondary shaft axis J3. The secondary shaft 13 rotates about the secondary shaft axis J3. The secondary shaft 13 has: a first end 13A located on the other side of the axial direction (+Y side); and a second end 13B located on one side of the axial direction (-Y side).

[0069] The first end 13A of the countershaft 13 is supported by a ball bearing 79 and is rotatable. The second end 13B of the countershaft 13 is supported by a ball bearing 78 and is rotatable. A countershaft gear 23 and a drive gear 24 are disposed on the outer circumferential surface of the countershaft 13 and axially between the first end 13A and the second end 13B. In this embodiment, the drive gear 24 is located on the other side (+Y side) of the axial direction of the countershaft gear.

[0070] The counterspindle gear 23 rotates together with the counterspindle 13 around the counterspindle axis J3. The counterspindle gear 23 meshes with the input gear 21.

[0071] The drive gear 24 rotates together with the secondary shaft 13 and the secondary shaft gear 23 around the secondary shaft axis J3.

[0072] The gear ring 51 is a gear centered on the motor axis J1. The gear ring 51 is fixed to the differential device 50. The gear ring 51 rotates around the motor axis J1. The gear ring 51 meshes with the drive gear 24. The gear ring 51 transmits the power of the motor 1 transmitted via the drive gear 24 to the differential device 50.

[0073] The differential 50 is configured with the motor axis J1 as its center. That is, the differential 50 is mounted on the same axis as the motor 1. The differential 50 is a device for transmitting the torque output from the motor 1 to the wheels H of the vehicle. The differential 50 has the function of absorbing the speed difference between the left and right wheels H when the vehicle is turning and transmitting the same torque to the output shafts 55 of both wheels.

[0074] The differential device 50 includes: a gear housing 52 fixed to a gear ring 51; a pair of pinions 53a; a pinion shaft 53b; and a pair of side gears 54. The gear housing 52 and the gear ring 51 rotate together about the motor axis J1.

[0075] The gear housing 52 houses a pair of pinions 53a, a pinion shaft 53b, and a pair of side gears 54. The pair of pinions 53a are coaxial and opposite bevel gears. The pair of pinions 53a are supported on the pinion shaft 53b. The pair of side gears 54 are bevel gears that mesh at right angles with the pair of pinions 53a. The pair of side gears 54 are respectively fixed to the output shaft 55.

[0076] The gear housing 52 is rotatable by tapered roller bearings 76 and 77 on both sides of the axial direction. That is, the gear ring 51 is supported by the tapered roller bearings 76 and 77 via the gear housing 52.

[0077] Output shaft 55 extends along motor axis J1. Output shaft 55 rotates about motor axis J1. A pair of output shafts 55 arranged axially are provided in motor unit 10. Each pair of output shafts 55 is connected at one end to the side gear 54 of differential device 50. That is, output shaft 55 is connected to gear ring 51 via differential device 50. Power from motor 1 is transmitted to output shaft 55 via each gear. In addition, each pair of output shafts 55 protrudes outward from the other end of housing 6. A wheel H is mounted at the other end of output shaft 55. Output shaft 55 transmits power to the outside (to the road surface via wheel H).

[0078] In this embodiment, the output shaft 55 is arranged coaxially with the motor shaft 32 and the input shaft 11. One of the pair of output shafts 55 is arranged on one axial side (-Y side) and passes through the hollow portions 32h and 11h of the motor shaft 32 and the input shaft 11. According to the motor unit 10 of this embodiment, a portion of the output shaft 55 is arranged inside the motor shaft 32 and the input shaft 11. Therefore, the motor 1 and the differential device 50 can be arranged coaxially when viewed from the axial direction, and the radial dimension of the motor axis J1 of the motor unit 10 can be miniaturized.

[0079] The gear section 5 forms the power transmission path from the motor 1 to the output shaft 55. The gear section 5 has multiple gears (input gear 21, counterspindle gear 23, drive gear 24, ring gear 51, pinion 53a, and side gear 54). The gear section 5 transmits power from the motor shaft 32 to the output shaft 55 through these multiple gears. In the power transmission path of the gear section 5, the power of the motor 1 is first transmitted from the motor shaft 32 to the input shaft 11, and further from the input gear 21 to the counterspindle gear 23. The counterspindle gear 23 is arranged coaxially with the drive gear 24 and rotates together with the drive gear 24. The power of the motor 1 is transmitted from the drive gear 24 to the ring gear 51, and then via the differential device 50 to the output shaft 55.

[0080] (Stator cage)

[0081] The stator retainer 40 has: a cylindrical portion 41 that surrounds the stator 35 from the radially outer side; and a base plate portion 42 that extends radially inward from one end of the cylindrical portion 41 on one axial side (-Y side).

[0082] The stator retainer 40 is disposed inside the cylindrical portion 60a of the housing body 60. The cylindrical portion 60a of the housing body 60 has opposing inner circumferential surfaces 60aa facing radially inward. The opposing inner circumferential surfaces 60aa are radially opposed to the outer circumferential surfaces 41a of the cylindrical portion 41.

[0083] The cylindrical portion 41 is cylindrical with the motor axis J1 as its center. The stator 35 is supported by fitting the outer peripheral surface of the stator 35 into the inner peripheral surface 41b of the cylindrical portion 41. Thus, the stator cage 40 supports the stator 35.

[0084] An insert portion 41p is provided on the inner circumferential surface 41b of the cylindrical portion 41. The insert portion 41p is provided on the opening on the other axial side (+Y side) of the cylindrical portion 41. The inner diameter of the insert portion 41p is larger than the inner diameter of the area in the inner circumferential surface 41b where the stator 35 is fitted. A first retainer 81 of the shaft retainer 80 is embedded in the insert portion 41p.

[0085] A radially recessed recess (passage portion) 44 is provided on the outer peripheral surface 41a of the cylindrical portion 41. The recess 44 extends throughout the entire circumference of the motor axis J1. The recess 44 opens radially outward. The opening of the recess 44 is covered by the opposing inner peripheral surface 60aa of the housing body 60.

[0086] The recess 44 functions as a passage for the refrigerant W to flow through. The refrigerant W flows circumferentially between the inner wall surface of the recess 44 and the opposing inner circumferential surface 60aa. The refrigerant W cools the stator 35 via the stator retainer 40. The refrigerant W is cooled by passing through a heat exchanger (not shown). Therefore, the stator retainer 40 and the cylindrical portion 60a of the outer casing 60 function as a water-cooling jacket that surrounds the stator 35 and allows the refrigerant W to pass through, thereby cooling the stator 35.

[0087] In this embodiment, a recess 44 is provided on the outer peripheral surface 41a of the cylindrical portion 41, and the opening of the recess 44 is covered by the opposing inner peripheral surface 60aa. However, a structure in which a recess is provided on the opposing inner peripheral surface 60aa and the opening of the recess is covered by the outer peripheral surface 41a of the cylindrical portion 41 is also possible. Furthermore, the structure through which the refrigerant W passes is not limited to this embodiment; a passage portion for the refrigerant W to pass through may also be provided between the outer peripheral surface 41a and the opposing inner peripheral surface 60aa of the cylindrical portion 41.

[0088] A pair of fitting portions 46 are provided on the outer peripheral surface 41a of the cylindrical portion 41, which are embedded into the opposing inner peripheral surface 60aa. The fitting portions 46 extend around the entire circumference of the motor axis J1. One of the pair of fitting portions 46 is located on the opposite axial side of the recess 44, and the other is located on one axial side of the recess 44. According to this embodiment, the stator cage 40 is embedded into the opposing inner peripheral surface 60aa of the housing body 60 at the fitting portions 46. As a result, the radial positional accuracy of the stator cage 40 relative to the housing body 60 can be improved.

[0089] A pair of grooves 45a are provided on the outer peripheral surface 41a of the cylindrical portion 41. The grooves 45a extend around the entire circumference of the motor axis J1. One of the grooves 45a is located on the opposite axial side of the recess 44, and the other is located on one axial side of the recess 44. Both grooves 45a are axially positioned between a pair of mating portions 46. The grooves 45a open radially outward. The openings of the grooves 45a are covered by the opposing inner peripheral surfaces 60aa of the housing body 60. O-rings (sealing portions) 45b are respectively housed in the pair of grooves 45a. The O-rings 45b are radially compressed by the opposing inner peripheral surfaces 60aa. Thus, the O-rings 45b function as sealing portions.

[0090] Alternatively, a structure can be adopted in which a groove for receiving the O-ring is provided on the opposing inner circumferential surface 60aa, and the O-ring is compressed by the outer circumferential surface 41a of the cylindrical portion 41. That is, the O-ring 45b, which serves as a sealing part, only needs to be disposed between the outer circumferential surface 41a of the cylindrical portion 41 and the opposing inner circumferential surface 60aa, and extend along the circumferential direction.

[0091] According to this embodiment, O-rings 45b are located on both axial sides of the recess 44, which serves as a passage for the refrigerant W. The O-rings 45b suppress refrigerant W from leaking out of the recess 44 to both axial sides. Furthermore, they suppress oil O from entering between the pair of O-rings 45b within the drive body housing space 61. Thus, mixing of oil O with the refrigerant W within the recess 44 is suppressed.

[0092] The base plate portion 42 is located on one axial side (-Y side) relative to the motor 1. The base plate portion 42 is plate-shaped and orthogonal to the motor axis J1. A through hole 42a is provided in the center of the base plate portion 42. The through hole 42a extends through the base plate portion 42 along the thickness direction. The base plate portion 42 has a bearing retaining portion 43, which protrudes from the edge of the through hole 42a to the other axial side (+Y side). The base plate portion 42 holds the ball bearing 72. Therefore, the base plate portion 42 can support the motor shaft 32 for rotation via the ball bearing 72.

[0093] According to this embodiment, the stator cage 40, which supports the stator 35, supports the rotor 31 via ball bearings 72. That is, the components between the stator 35 and the rotor 31 are only the stator cage 40 and the ball bearings 72. Therefore, according to this embodiment, by managing the dimensions of the stator cage 40, the coaxiality of the rotor 31 relative to the stator 35 can be improved, making it easier to improve the drive efficiency of the motor 1.

[0094] According to this embodiment, the base plate portion 42 of the stator cage 40 holds the ball bearing 72. Therefore, compared to the case where a separate component is provided to hold the ball bearing 72, it is easier to reduce the overall size of the motor unit 10 in the axial direction. In particular, in this embodiment, the axial position of the bearing holding portion 43 of the stator cage 40 overlaps with the axial position of the stator 35. As a result, the motor unit 10 can be reduced in the axial direction more effectively.

[0095] The output shaft 55 protrudes from an opening on the axial side (-Y side) of the motor shaft 32. According to this embodiment, the output shaft 55 and the motor shaft 32 are supported by ball bearings 71 and 72 arranged axially. One of the ball bearings 71 and 72 is held in the housing body 60, and the other is held in the stator cage 40. According to this embodiment, compared to the case where both ball bearings 71 and 72 are held in the housing body 60, the structure of the housing body 60 can be simplified, and the assembly process as a whole can be simplified.

[0096] According to this embodiment, the ball bearing 72 is disposed radially inside one of the two coil end portions 35c of the stator 35, located on the axial side. More specifically, the axial position of the ball bearing 72 overlaps with the axial position of the coil end portion 35c located on the axial side. Therefore, the ball bearing 72 supporting the second end portion 32B of the motor shaft 32 can be disposed near the first end portion 32A. As a result, the bearings 72 and 73 supporting the two ends of the motor shaft 32 can be disposed close to each other, which can suppress eccentricity of the motor shaft 32. Furthermore, the oil O that cools the coil end portion 35c and drips from the coil end portion 35c can be supplied to the ball bearing 72, which can improve the lubricity of the ball bearing 72.

[0097] The base plate 42 of the stator cage 40 supports the resolver stator 3b in addition to supporting the ball bearing 72. The resolver stator 3b is disposed inside the through hole 42a and is positioned axially further than the ball bearing 72. The resolver stator 3b surrounds the second end 32B of the motor shaft 32 from the radially outer side. The resolver stator 3b is radially opposed to the resolver rotor 3a.

[0098] The resolver stator 3b and resolver rotor 3a constitute the resolver. That is, the motor unit 10 includes resolver 3. Resolver 3 measures the rotational speed of the motor shaft 32. Resolver 3 is axially positioned between ball bearing 71 and ball bearing 72.

[0099] According to this embodiment, the base plate 42 of the stator cage 40 supports the resolver stator 3b. Therefore, compared to the case where the housing body 60 supports the resolver stator 3b, the resolver stator 3b can be positioned close to the center of the axial dimension of the motor 1. As a result, the axial protrusion of the resolver stator 3b relative to the motor 1 can be suppressed, and the axial dimension of the motor unit 10 can be miniaturized.

[0100] (Shaft retaining part)

[0101] The shaft retainer 80 is disposed in the drive body storage space 61. Furthermore, the shaft retainer 80 is located between the motor 1 and the gear section 5. The shaft retainer 80 includes a first retainer 81, a second retainer 86, ball bearings 73, 74, 75, and 78, and a tapered roller bearing 76.

[0102] The first retainer 81 is fixed to the stator cage 40 from the other axial side (+Y side). Furthermore, the second retainer 86 is fixed to the first retainer 81 from the other axial side (+Y side). Ball bearings 73, 74, and 78 are held in the first retainer 81. Additionally, ball bearing 75 and tapered roller bearing 76 are held in the second retainer 86.

[0103] Figure 3 This is an exploded perspective view of the shaft retaining part 80.

[0104] The first retainer 81 has a main disc portion 82 and a protruding disc portion 83. The main disc portion 82 and the protruding disc portion 83 are a single component connected to each other. The diameter of the main disc portion 82 is larger than the diameter of the protruding disc portion 83. The protruding disc portion 83 is offset from the main disc portion 82 in the radial and axial directions to the other side (+Y side).

[0105] The main disc portion 82 is disc-shaped with the motor axis J1 as its center. A first through hole 82h is provided in the center of the main disc portion 82, extending axially. When viewed axially, the first through hole 82h is circular with the motor axis J1 as its center. Inside the first through hole 82h, the first end 32A of the motor shaft 32, the second end 11B of the input shaft 11, and the output shaft 55 are arranged.

[0106] A plurality of threaded holes 82s are provided on the surface of the main body disk portion 82 on the other side (+Y side) axially. The plurality of threaded holes 82s are arranged circumferentially along the motor axis J1 in a manner that surrounds the first through hole 82h. Fixing screws 84 for fixing the second retainer 86 are inserted into the threaded holes 82s. That is, the second retainer 86 is fixed by a plurality of fixing screws 84 inserted relative to the first retainer 81 toward the axial side (-Y side). As a result, the second retainer 86 can be installed on the first retainer 81 from the first opening 61a side within the drive body storage space 61, thus simplifying the assembly process of the motor unit 10. Moreover, the plurality of fixing screws 84 are arranged circumferentially along the motor axis J1. Therefore, the second retainer 86 can be securely fixed around the motor axis J1.

[0107] The protruding disc portion 83 is disc-shaped with the secondary shaft axis J3 as its center. A second through hole 83h is provided in the center of the protruding disc portion 83, extending axially. The second end portion 13B of the secondary shaft 13 is disposed inside the second through hole 83h.

[0108] like Figure 1 As shown, the main body disk portion 82 has an outer edge protrusion 82c, which protrudes from the outer edge of the main body disk portion 82 toward one axial side (-Y side). The outer edge protrusion 82c is cylindrical about the motor axis J1. The outer peripheral surface of the outer edge protrusion 82c fits into the insert portion 41p of the stator retainer 40. Thus, the first retainer 81 is supported on the stator retainer 40. Furthermore, the first retainer 81 is fixed to the housing body 60 via the stator retainer 40.

[0109] The main disc portion 82 has two bearing retaining portions 82a and 82b. The bearing retaining portions 82a and 82b are located on the outer edge of the first through hole 82h.

[0110] A bearing retainer 82a is provided on the axially facing (-Y side) surface of the main body disk portion 82. The bearing retainer 82a holds the ball bearing 73. Thus, the bearing retainer 82a supports the first end 32A of the motor shaft 32 so that it can rotate via the ball bearing 73. The ball bearing 73 is located axially between the motor 1 and the gear portion 5. Therefore, the shaft retainer 80 supports the motor shaft 32 so that it can rotate on the other axial side of the motor 1.

[0111] In this embodiment, the motor 1 and the gear unit 5 are housed in an integrated drive body storage space 61. Therefore, without the shaft retaining part 80, the motor shaft 32 becomes a cantilever support, which may cause significant eccentricity during rotation. According to this embodiment, the shaft retaining part 80 rotatably holds the motor shaft 32 between the motor 1 and the gear unit 5. Therefore, the shaft retaining part 80, together with the ball bearing 72 supporting the second end 32B, can support the motor shaft 32 on both sides of the motor 1. According to this embodiment, eccentricity of the motor shaft 32 can be suppressed, thereby improving the rotational efficiency of the motor shaft 32.

[0112] A bearing retainer 82b is provided on the surface of the main body disk portion 82 facing the other side (+Y side) of the axial direction. The bearing retainer 82b holds the ball bearing 74. Thus, the bearing retainer 82b supports the input shaft 11 for rotation via the ball bearing 74.

[0113] The protruding disc portion 83 has a bearing retaining portion 83a. The bearing retaining portion 83a is provided on the outer edge of the second through hole 83h. The bearing retaining portion 83a is provided on the surface of the protruding disc portion 83 facing the other side (+Y side) of the axial direction. The bearing retaining portion 83a supports the ball bearing 78. The bearing retaining portion 83a supports the sub-shaft 13 so that it can rotate via the ball bearing 78.

[0114] According to this embodiment, the first retainer 81 not only supports the shafts (motor shaft 32 and input shaft 11) on the motor shaft J1 to be rotatable, but also supports the shaft (sub-shaft 13) on the secondary shaft shaft J3 to be rotatable. Therefore, by managing the machining accuracy of the first retainer 81, the distance between the motor shaft J1 and the secondary shaft shaft J3 can be guaranteed, resulting in improved power transmission efficiency between gears. Furthermore, by mounting the first retainer 81 to the housing body 60 with multiple bearings (ball bearings 73, 78) installed, the assembly process can be simplified.

[0115] The axial positions of ball bearing 73 and ball bearing 78 can also overlap. Furthermore, the axial positions of ball bearing 74 and ball bearing 78 can also overlap. That is, ideally, the axial positions of the multiple bearings in the shaft retaining portion 80 overlap. Therefore, compared to the case where the bearings are staggered, the axial dimension of the shaft retaining portion 80 can be reduced, thereby effectively utilizing the drive unit storage space 61. Furthermore, among the multiple bearings with overlapping axial positions, radially dispersed oil O can be supplied from one bearing to the other bearings, thereby improving bearing lubrication.

[0116] like Figure 3 As shown, the second retainer 86 has a surrounding portion 88 and a flange portion 89. The surrounding portion 88 and the flange portion 89 are a single component that is interconnected.

[0117] The surrounding portion 88 is annular, surrounding the motor shaft J1 from the radially outer side. The surrounding portion 88 has: a disc portion 88a; and a surrounding cylindrical portion 88b, which extends from the outer edge of the disc portion 88a toward one side in the axial direction.

[0118] The disc portion 88a is disc-shaped with the motor axis J1 as its center. A third through hole 88h is provided in the center of the disc portion 88a, extending axially. When viewed axially, the third through hole 88h is circular with the motor axis J1 as its center. An output shaft 55 is disposed inside the third through hole 88h.

[0119] The disc portion 88a has two bearing retaining portions 88e and 88f. The bearing retaining portions 88e and 88f are located on the outer edge of the third through hole 88h.

[0120] The surrounding cylindrical portion 88b is cylindrical with the motor axis J1 as its center. The surrounding cylindrical portion 88b opens towards one axial side (-Y side). A notch portion 88c is provided in the surrounding cylindrical portion 88b. The notch portion 88c extends from the end of the surrounding cylindrical portion 88b on one axial side (-Y side) towards the other axial side (+Y side). The notch portion 88c is provided in the upper region of the entire circumference of the surrounding cylindrical portion 88b.

[0121] The second retainer 86 is fixed to the first retainer 81 to block the axial side (-Y side) of the notch 88c through the first retainer 81. Thus, the notch 88c functions as an opening 87 that exposes the interior of the surrounding portion 88 to the upward side.

[0122] The flange portion 89 is located at the end of the surrounding portion 88 on one axial side (-Y side). More specifically, the flange portion 89 extends radially outward from the end of the surrounding cylindrical portion 88b on one axial side. A plurality of through holes 89a are provided in the flange portion 89, extending axially. The plurality of through holes 89a are arranged circumferentially along the motor axis J1. To secure the second retainer 86 to the first retainer 81, a fixing screw 84 is inserted through the through hole 89a and into the threaded hole 82s of the first retainer 81. Thus, the second retainer 86 is supported by the first retainer 81.

[0123] like Figure 1 As shown, the bearing retaining portion 88f of the second retainer 86 is provided on the axially facing (-Y side) surface of the disk portion 88a. The bearing retaining portion 88f holds the ball bearing 75. Thus, the bearing retaining portion 88f supports the output shaft 55 for rotation via the ball bearing 75.

[0124] A bearing retainer 88e is provided on the surface of the disc portion 88a facing the other side (+Y side) of the axial direction. The bearing retainer 88e holds the tapered roller bearing 76. Thus, the bearing retainer 88e supports the gear housing 52 and the gear ring 51 for rotation via the tapered roller bearing 76.

[0125] According to this embodiment, a second retainer 86, which supports the output shaft 55 via a ball bearing 75, is fixed to a first retainer 81. The first retainer 81 supports the motor shaft 32 and the input shaft 11 via ball bearings 73 and 74. Therefore, according to this embodiment, the coaxiality of the output shaft 55 with respect to the motor shaft 32 and the input shaft 11 can be ensured based on the installation accuracy of the second retainer 86 relative to the first retainer 81. Therefore, the rotational efficiency of the motor shaft 32 and the input shaft 11 is easily improved.

[0126] According to this embodiment, the shaft retaining portion 80 has a surrounding portion 88 that surrounds the motor shaft, and an opening 87 that opens radially along the motor shaft J1 is provided in the surrounding portion 88. The opening 87 communicates the inside and outside of the surrounding portion 88. This allows oil O that has been dispersed into the drive housing space 61 by the gear ring 51 to reach the surrounding portion 88, thus supplying the dispersed oil O to the interior of the surrounding portion 88. Furthermore, in this embodiment, the opening 87 exposes the ball bearings 74 and 75 into the drive housing space 61. Therefore, according to this embodiment, oil O can be supplied to the ball bearings 74 and 75 from the opening 87, improving the lubrication of the ball bearings 74 and 75.

[0127] In this embodiment, the opening 87 opens upwards. Therefore, oil O that reaches the interior of the enclosure 88 from the opening 87 can accumulate inside the enclosure 88. That is, the enclosure 88 has an oil storage space 64 for storing oil O. Furthermore, the opening 87 and the oil storage space 64 are disposed in the second retainer 86.

[0128] In this embodiment, the surrounding portion 88 of the shaft retaining portion 80 surrounds the first end portion 11A of the input shaft 11. Therefore, the hollow portion 11h of the input shaft 11 opens within the oil receiving space 64. A portion of the oil O in the oil receiving space 64 infiltrates the hollow portion 11h, thereby improving the lubrication between the inner circumferential surface of the input shaft 11 and the output shaft 55. Furthermore, oil O is supplied to the male splines 11a and female splines 32b at the connection between the input shaft 11 and the motor shaft 32, thereby suppressing wear at the connection. Oil O scatters from the connection between the male splines 11a and female splines 32b and is supplied to the ball bearing 73 that supports the motor shaft 32, thereby improving the lubrication of the ball bearing 73.

[0129] In this embodiment, at least a portion of the input gear 21, which is disposed at the first end 11A of the input shaft 11, is located within the oil storage space 64. Therefore, the lower end of the input gear 21 is immersed in the oil O accumulated in the oil storage space 64. The oil O is lifted by the movement of the input gear 21 and diffused into the drive body storage space 61, and spreads throughout the tooth surfaces of each gear.

[0130] In this embodiment, the meshing portion 14 where the input gear 21 meshes with the counterspindle gear 23 is disposed in the opening portion 87. Therefore, the shaft retaining portion 80 can support the shaft on both axial sides of the input gear 21 and transmit power from the input gear 21 to the counterspindle gear 23.

[0131] According to this embodiment, the shaft retaining part 80 has a plurality of bearing retaining parts 82a, 82b, 88f, 88e, and 83a for retaining bearings respectively. Bearing retaining parts 82a, 82b, and 83a are disposed in the first retainer 81, and bearing retaining parts 88f and 88e are disposed in the second retainer 86. Thus, since the first retainer 81 and the second retainer 86, which are separable from each other, each have bearing retaining parts, they can be installed separately in the separated state, thereby simplifying the assembly process. Furthermore, bearings can be installed from both axial sides of the first retainer 81 and the second retainer 86, thereby improving the axial and radial positional accuracy of each bearing.

[0132] (Inverter)

[0133] like Figure 1As shown, inverter 8 is disposed in inverter housing space 62. Inverter 8 is fixed to inverter cover 68. Inverter 8 is connected to stator 35 of motor 1 via bus 9. Inverter 8 converts direct current into alternating current and supplies it to motor 1. That is, inverter 8 controls the current supplied to motor 1.

[0134] The inverter 8 is disposed on the outer peripheral side of the motor 1. More specifically, the inverter 8 is located directly above the motor 1. This allows for a reduction in the longitudinal dimension of the motor unit 10. Consequently, compared to the case where the inverter 8 is disposed relative to the motor 1 in the longitudinal direction of the vehicle, the longitudinal dimension of the motor unit 10 can be reduced. As a result, the collision absorption area within the vehicle can be significantly improved.

[0135] When viewed in the axial direction, at least a portion of the inverter 8 overlaps with the countershaft gear 23. By configuring the inverter 8 to overlap with the countershaft gear 23, the axial projected area of ​​the motor unit 10 is reduced, thereby enabling miniaturization of the motor unit 10.

[0136] Busbar 9 is made of a conductive metallic material. Busbar 9 electrically connects motor 1 and inverter 8 together. In this embodiment, motor 1 is a three-phase AC motor; therefore, motor unit 10 has three corresponding inverters 8.

[0137] The busbar 9 has: an axial extension 9a that extends axially; and a radial extension 9b that extends radially along the motor axis J1.

[0138] One axial side (-Y side) of the axial extension 9a is connected to the inverter 8. Furthermore, the other axial side (+Y side) of the axial extension 9a is connected to the radial extension 9b. The radial extension 9b extends radially inward from the end of the axial extension and is connected to the connecting coil line 35d at its front end. That is, the busbar 9 is connected to the inverter 8 at the axial extension 9a and to the connecting coil line 35d at the radial extension 9b.

[0139] The axial extension 9a passes through a through hole 60h, which is provided in a partition 66 that divides the drive unit housing space 61 and the inverter housing space 62. Thus, the busbar 9 is positioned between the drive unit housing space 61 and the inverter housing space 62.

[0140] Furthermore, busbar 9 is held by a busbar cage (not shown in the figure). The busbar cage has a sealing structure disposed between the inner circumferential surface of the through hole 60h and busbar 9, thereby sealing the drive unit housing space 61 and the inverter housing space 62. Thus, the busbar cage prevents oil O from the drive unit housing space 61 from intruding into the inverter housing space 62.

[0141] According to this embodiment, the through hole 60h through which the busbar 9 passes is provided in the side wall portion 60db. The side wall portion 60db is located on the other side of the inverter 8 along the axial direction and between the inverter 8 and the gear portion 5. Furthermore, the through hole 60h extends through the side wall portion 60db along the axial direction. As described above, the drive body storage space 61 opens at the first opening 61a toward the other side (+Y side) along the axial direction. Therefore, the assembly operator can install the busbar 9 onto the housing body 60 by storing it in the drive body storage space 61 from the first opening 61a and inserting it into the through hole 60h. According to this embodiment, the busbar 9 can be installed relative to the housing body 60 from the first opening 61a in the same way as other components, and the assembly process can be simplified by installing it from one direction.

[0142] <Oil Circuit>

[0143] Oil passage 90 is the path through which oil 0 circulates within housing 6. Oil passage 90 is located within housing 6. Oil pump 96 is installed in oil passage 90.

[0144] In addition, in this specification, the concept of "oil path" includes not only the "flow path" that forms a stable flow of oil that always faces one direction, but also the path where oil is temporarily retained (e.g., oil storage space 63) and the path where oil drips.

[0145] The oil passage 90 includes: a first flow path 91 that guides oil O from the oil storage space 63 to the oil pump 96; and a second flow path 97 that extends from the oil pump 96 toward the upper side of the motor 1 and supplies oil O to the motor 1. Oil O reaches the oil pump 96 from the oil storage space 63 via the first flow path 91 and is supplied to the motor 1 from the oil pump 96 via the second flow path 97. Furthermore, oil O drips from the motor 1 and returns to the oil storage space 63.

[0146] The first flow path 91 and the second flow path 97 are disposed inside the wall of the housing body 60. The first flow path 91 connects from the oil storage space 63 to the oil pump 96. On the other hand, the second flow path 97 extends upward from the oil pump 96 and branches off, opening on the upper side of a pair of coil edge ends 35c of the stator 35.

[0147] Oil pump 96 is located on the axial side (-Y side) of motor 1. Oil pump 96 is a mechanical pump connected to output shaft 55 and driven by the rotation of output shaft 55. Oil pump 96 draws oil O from oil storage space 63 and pressurizes it into oil passage 90.

[0148] Figure 4 This is a schematic diagram of the oil pump 96 as viewed from the axial direction.

[0149] The oil pump 96 has a pump housing 96a, an external gear 92, and an internal gear 93.

[0150] The pump housing 96a is fixed to the bottom 60b of the outer casing 60. In this embodiment, the pump housing 96a is circular when viewed from the axial direction. The pump housing 96a is provided with a pump chamber 96c, a suction port 94, and a discharge port 95.

[0151] When viewed axially, pump chamber 96c is circular with axis J2 eccentric to the motor axis J1 as its center. Inlet 94 and outlet 95 are connected to pump chamber 96c. External gear 92 and internal gear 93 are disposed within pump chamber 96c.

[0152] The suction port 94 and discharge port 95 open onto the axial side of the pump chamber 96c. The suction port 94 is connected to the first flow path 91. The discharge port 95 is connected to the second flow path 97. The oil pump 96 draws oil O in through the suction port 94 and discharges oil O through the discharge port 95.

[0153] External gear 92 is a gear that can rotate about the motor axis J1. External gear 92 is fixed to the output shaft 55. External gear 92 is housed in the pump chamber 96c. External gear 92 has multiple teeth 92a on its outer circumferential surface. The tooth profile of the teeth 92a of external gear 92 is a cocycloidal tooth profile.

[0154] The internal gear 93 is a ring-shaped gear that can rotate about an axis J2 that is eccentric to the motor axis J1. The outer diameter of the internal gear is slightly smaller than the inner diameter of the pump chamber 96c. The outer circumferential surface of the internal gear 93 can slide against the inner circumferential surface of the pump chamber 96c.

[0155] The internal gear 93 surrounds the radially outer side of the external gear 92 and meshes with the external gear 92. The internal gear 93 has multiple teeth 93a on its inner circumferential surface. The tooth profile of the teeth 93a of the internal gear 93 is a cocycloidal tooth profile.

[0156] The external gear 92 rotates around the motor axis J1, causing both the external gear 92 and the internal gear 93 meshing with it to rotate around the axis J2. This causes the gap between the teeth 92a of the external gear 92 and the teeth 93a of the internal gear 93 to move circumferentially, and the oil pump 96 transfers the oil O within this gap from the suction port 94 to the discharge port 95. Thus, the oil pump 96 draws in oil O from the suction port 94 and discharges it from the discharge port 95.

[0157] Oil O discharged from oil pump 96 is supplied to a pair of coil end points 35c via second flow path 97. The oil O supplied to the coil end points 35c permeates the entire coil 35b under the action of capillary force and gravity acting between the coil wires, while simultaneously drawing heat from the stator 35. Then, the oil O drips downwards and returns to the oil storage space 63 through holes and connecting holes 65 provided in the stator retainer 40.

[0158] According to this embodiment, the stator core 35a is cooled by the refrigerant W via the stator retainer 40, and the coil edge end 35c is directly cooled by the oil O. Therefore, each part of the stator 35 can be cooled efficiently.

[0159] In this embodiment, oil O is stored in oil storage space 63. A motor 1 is positioned directly above the oil storage space 63, and a passageway (recess 44) for refrigerant W is provided around the motor 1. Therefore, the oil O in the oil storage space 63 is cooled by the refrigerant W. Thus, the oil O is supplied to the coil edge 35c while its temperature has decreased, thereby efficiently cooling the coil edge 35c.

[0160] (Manufacturing method of motor unit)

[0161] Next, based on Figure 1 The installation steps of each component relative to the outer casing 60 will be described as a manufacturing method for the motor unit 10.

[0162] The manufacturing method of the motor unit 10 mainly includes the following first to ninth steps.

[0163] <First Process>

[0164] The first step is the output shaft mounting step, which involves installing the output shaft 55 onto the housing body 60. Prior to this first step, a bottom cover member 69 is pre-installed on the housing body 60. Thus, the bottom cover member 69 covers the third opening 63a of the housing body 60.

[0165] In the first step, a sealing member (not shown) and a ball bearing 71 are first installed in the bearing retaining portion 60ba located at the bottom 60b of the housing body 60. Next, the output shaft 55 is housed from the first opening 61a of the housing body 60 into the drive body housing space 61. Then, the output shaft 55 is mounted to the housing body 60 by inserting the end of the output shaft 55 on its axial side (-Y side) into the ball bearing 71. Finally, the oil pump 96 is mounted to the output shaft 55.

[0166] <Second Process>

[0167] The second step is the motor installation step, which involves mounting the motor 1 onto the housing body 60. Prior to this second step, the rotor 31 and the stator 35 are pre-assembled. Furthermore, the stator 35, together with the ball bearing 72, is pre-installed onto the stator cage 40.

[0168] In the second step, firstly, the pre-assembled stator 35 and stator cage 40 are stored in the drive body storage space 61 through the first opening 61a. Furthermore, the fitting portion 46 of the stator cage 40 is inserted into the opposing inner circumferential surface 60aa of the cylindrical portion 60a of the outer casing 60. Thus, the stator cage 40 and stator 35 are fixed to the outer casing 60.

[0169] In the second process, the output shaft 55 is then inserted into the hollow portion 32h of the motor shaft 32, while the rotor 31 is stored in the drive body storage space 61 from the first opening 61a.

[0170] After the above steps, in the second process, the motor 1 and the stator cage 40 are stored and fixed in the drive body storage space 61 from the first opening 61a of the housing body 60.

[0171] <Third Process>

[0172] The third step is the busbar installation step, which involves installing the busbars 9 onto the housing body 60. In this third step, the three busbars 9 are housed in the drive body housing space 61 from the first opening 61a of the housing body 60, and then fixed to the housing body 60 through the through hole 60h. Next, the busbars 9 are connected to the connecting coil wire 35d extending from the stator 35.

[0173] <Fourth Process>

[0174] The fourth step is to install the first retainer 81 onto the stator cage 40. Prior to the fourth step, ball bearings 73 and 78 are pre-installed on the first retainer 81.

[0175] In the fourth step, firstly, the first retainer 81 is housed from the first opening 61a of the housing body 60 into the drive body housing space 61, and the motor shaft 32 is inserted into the ball bearing 73. Furthermore, the outer protrusion 82c of the first retainer 81 is engaged with the insertion portion 41p of the stator retainer 40, thereby fixing the first retainer 81 to the housing body 60 via the stator retainer 40. Next, the ball bearing 74 is installed onto the first retainer 81.

[0176] <Fifth Process>

[0177] The fifth step is to install the input shaft 11, the countershaft 13, the input gear 21, the countershaft gear 23, and the drive gear 24 onto the housing body 60. In the fifth step, the input shaft 11, the countershaft 13, the input gear 21, the countershaft gear 23, and the drive gear 24 are taken out from the first opening 61a of the housing body 60 and placed into the drive body storage space 61 and installed.

[0178] <Sixth Process>

[0179] The sixth step is to install the second retainer 86 onto the first retainer 81. Prior to the sixth step, a ball bearing 75 and a tapered roller bearing 76 are pre-installed on the second retainer 86.

[0180] In the sixth step, firstly, the second retainer 86 is housed from the first opening 61a of the housing body 60 into the drive body housing space 61, and the output shaft 55 is inserted into the ball bearing 75. Furthermore, the second retainer 86 is fixed to the first retainer 81.

[0181] By installing the first retainer 81 and the second retainer 86 in the fourth and sixth processes, the shaft retainer 80 is housed and fixed from the first opening 61a of the housing body 60 into the drive body storage space 61.

[0182] <Seventh Process>

[0183] The seventh step is to install the gear ring 51 and the differential device 50 onto the shaft retaining part 80. Prior to the seventh step, the differential device 50 is pre-assembled, and the gear ring 51 is installed onto the gear housing 52 of the differential device 50.

[0184] In the seventh step, the gear housing 52 is held in the tapered roller bearing 76, and the output shaft 55 is connected to the side gear 54 of the differential device 50.

[0185] The fifth and seventh steps described above are gear assembly steps in which the gear part 5 is housed from the first opening 61a into the drive body housing space 61 and fixed.

[0186] <Eighth Process>

[0187] The eighth step is to install the sealing component 67 onto the housing body 60. Prior to the eighth step, ball bearings 79 and tapered roller bearings 77 are pre-assembled on the sealing component 67.

[0188] In the eighth step, firstly, the housing body 60 is installed and secured by covering the first opening 61a with the sealing member 67. At the same time, the countershaft 13 is inserted into the ball bearing 79, and the gear housing 52 is held in the tapered roller bearing 77.

[0189] The first to eighth steps described above are steps of installing the components, including the motor 1 and the gear unit 5, into the drive unit storage space 61 of the housing body 60. In the first to eighth steps, each component is installed into the housing body 60 from the other side (+Y side) of the axial direction. According to this embodiment, the first to eighth steps can be performed without changing the orientation of the housing body 60, and as a result, the time required to manufacture the motor unit 10 can be shortened.

[0190] <Ninth Process>

[0191] The ninth step is the process of installing the inverter 8 onto the housing body 60. Prior to the ninth step, the inverter 8 is pre-installed on the inverter cover 68. That is, the process of installing the inverter 8 includes a preparatory step of fixing the inverter 8 to the inverter cover 68.

[0192] In the ninth step, the inverter cover 68, on which the inverter 8 is installed, is fixed to the housing body 60. This places the inverter 8 in the inverter storage space 62, and the second opening 62a of the housing body 60 is covered by the inverter cover 68. Next, the window (not shown) on the upper surface of the inverter cover is opened, and within the inverter storage space 62, the busbar 9 is connected to the inverter 8, and the window is sealed again.

[0193] As described above, in the first to eighth steps, each component is installed onto the housing body 60 from the opening direction of the first opening 61a. However, in the ninth step, the inverter 8 and inverter cover 68 are installed onto the housing body 60 from the opening direction of the second opening 62a. Therefore, the assembly posture of the housing body 60 is changed before the ninth step. In this embodiment, the steps of installing the motor 1 and gear 5 (the first to eighth steps) are performed with the first opening facing upwards. Furthermore, the step of installing the inverter 8 (the ninth step) is performed with the second opening 62a facing upwards. This facilitates the assembly process.

[0194] The embodiments and variations of the present invention have been described above. However, each structure and combination thereof in the embodiments and variations is an example only, and structural additions, omissions, substitutions, and other changes can be made without departing from the spirit of the present invention. Moreover, the present invention is not limited to the embodiments.

[0195] (Symbol Explanation)

[0196] 1 Motor; 3 Resolver; 3a Resolver rotor; 3b Resolver stator; 5 Gear section; 6 Housing; 8 Inverter; 9 Busbar; 10 Motor unit; 11 Input shaft; 13 Sub-shaft; 14 Meshing section; 21 Input gear; 23 Sub-shaft gear; 31 Rotor; 32 Motor shaft; 35 Stator; 35a Stator core; 35b Coil; 35c Coil edge; 40 Stator cage; 41 Cylindrical section; 41a Outer circumferential surface; 41b Inner circumferential surface; 42 Base plate; 43 Bearing retainer (first bearing retainer); 44 Recess (passage section); 45b O-ring (sealing section); 46 Fitting section; 50 Differential device; 51 Gear ring; 55 Output shaft; 60 Housing body; 60aa Opposing inner circumferential surface; 60b Bottom; 60ba Bearing retainer (second bearing retainer); 60da Box bottom (partition); 60db Side wall (partition, first wall); 60h Through hole; 61 Drive unit storage space; 61a First opening; 62 Inverter storage space; 62a Second opening; 63 Oil storage space; 63a Third opening; 64 Oil storage space; 66 Partition; 68 Inverter cover; 71 Ball bearing (second bearing); 72 Ball bearing (first bearing); 73 Ball bearing; 74 Ball bearing; 75 Ball bearing; 76 Tapered roller bearing; 77 Tapered roller bearing; 78 Ball bearing; 79 Ball bearing; 80 Shaft retainer; 81 First retainer; 82a Bearing retainer; 82b Bearing retainer; 83a Bearing retainer; 84 Fixing screw; 86 Second retainer; 87 Opening; 88 Enclosure; 88e Bearing retainer; 88f Bearing retainer; J1 Motor shaft; J2 Shaft; J3 Sub-shaft shaft; O Oil; W Refrigerant.

Claims

1. A motor unit, wherein, include: A motor having a rotor and a stator, the rotor having a motor shaft that rotates about a motor axis, and the stator being located radially outside the rotor; A first bearing supports the motor shaft; A stator cage for holding the stator; A shaft retaining part is located axially between the motor and the gear part; as well as The housing body has a drive unit storage space and a first opening. The drive unit storage space houses the motor, the stator cage, and the shaft retainer. The first opening exposes the drive unit storage space to the other side axially. The stator cage has: A cylindrical portion that surrounds the stator radially outward; and The base plate extends radially inward from one end of the cylindrical portion along its axial direction. The outer shell body has opposing inner circumferential surfaces, which are radially opposed to the outer circumferential surface of the cylindrical portion. A passage for refrigerant flow is provided between the outer circumferential surface of the cylindrical portion and the opposing inner circumferential surface. The base plate holds the first bearing in place. A fitting portion that embeds into the opposing inner circumferential surface is provided on the outer circumferential surface of the cylindrical portion. The motor shaft is a hollow shaft. The motor unit has the gear section, which is connected to the other side of the motor's axial direction and housed within the housing body. The gear section has: An output shaft, a portion of which is disposed inside the motor shaft and rotates about the motor axis; and Multiple gears, which transmit power from the motor shaft to the output shaft. The housing body supports the output shaft via a second bearing on one axial side of the first bearing. The shaft retaining portion has: A motor shaft bearing that supports the motor shaft so that it can rotate; A first retainer holds the motor shaft in place with a bearing. Output shaft bearing, wherein the output shaft bearing supports the output shaft to enable rotation; and A second retainer is fixed to the first retainer from the other side of the axial direction and holds the output shaft in place by a bearing.

2. The motor unit as claimed in claim 1, wherein, The stator has an annular stator core and a coil wound around the stator core. The coil has coil edge ends that protrude axially to both sides from the stator core. The axial position of the first bearing overlaps with the axial position of the end of the coil of one of the bearings.

3. The motor unit as described in claim 1 or 2, wherein, It also includes a resolver that measures the rotational speed of the motor shaft. The parser has: The resolver stator, which is supported on the base plate portion; and The resolver rotor rotates together with the motor shaft about the motor axis.

4. The motor unit of claim 1 or 2, wherein, Also includes: The oil lubricates the gear assembly and is contained within the housing body. A sealing portion extending circumferentially is provided between the outer circumferential surface of the cylindrical portion and the opposing inner circumferential surface. The sealing parts are located on both sides of the axial direction of the passage.

5. The motor unit as claimed in claim 3, wherein, Also includes: The oil lubricates the gear assembly and is contained within the housing body. A sealing portion extending circumferentially is provided between the outer circumferential surface of the cylindrical portion and the opposing inner circumferential surface. The sealing parts are located on both sides of the axial direction of the passage.

6. The motor unit as claimed in claim 1, wherein, An axially arranged resolver is disposed between the first bearing and the second bearing, the resolver measuring the rotational speed of the motor shaft.

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