JP7491344B2 - Motor Unit - Google Patents

Description

The present invention relates to a motor unit.

Patent document 1 discloses a structure that includes a flow path that passes through the inside of the shaft to cool the motor, and a flow path that supplies oil from the top of the stator to cool the motor.

Patent No. 5911033

In the conventional structure, in addition to the two flow paths, a flow path was provided in which the two flow paths were joined, and a cooling device was provided in the joined flow path to cool the refrigerant. This made the flow path configuration complicated, which could lead to high costs.

An object of one aspect of the present invention is to provide a motor unit in which the configuration of oil passages is simplified to reduce costs.

One aspect of the motor unit of the present invention comprises a motor, a plurality of gears that transmit the torque of the motor, a housing provided with an accommodation space to accommodate the motor and the plurality of gears , oil that collects in an oil sump provided in a vertically lower area of the accommodation space, and an oil passage that supplies the oil from the oil sump to the motor and recovers it again in the oil sump, wherein the housing has a partition wall that divides the accommodation space into a motor chamber in which the motor is accommodated and a gear chamber in which the plurality of gears are accommodated, the partition wall is provided with a partition wall opening that connects the gear chamber and the motor chamber, the bottom of the motor chamber is located above the bottom of the gear chamber, the oil sump is provided in a lower area of the gear chamber, an electric pump is provided in the path of the oil passage, and the oil passage connects the oil sump and the electric pump as well as the electric pump and the motor chamber.

According to one aspect of the present invention , there is provided a motor unit in which the configuration of oil passages is simplified to reduce costs.

FIG. 1 is a conceptual diagram of a motor unit according to an embodiment. FIG. 2 is a perspective view of the motor unit according to the embodiment. FIG. 3 is a side view of the motor unit according to one embodiment. FIG. 4 is a cross-sectional view of the motor unit taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view of a rotor according to one embodiment. FIG. 6 is a plan view of the end plate. FIG. 7 is a cross-sectional view of the end plate taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view of an end plate according to a first modified example. FIG. 9 is a plan view of an end plate according to the second modified example. FIG. 10 is a cross-sectional view of the motor unit according to one embodiment, showing the second oil passage. FIG. 11 is a perspective view of a motor unit according to an embodiment with a portion of the housing omitted. FIG. 12 is a top view of a second reservoir in one embodiment. FIG. 13 is a perspective view of a second reservoir of the modified example. FIG. 14 is a cross-sectional view of a motor unit according to one embodiment, showing an outline of a secondary reservoir. FIG. 15 is a front view of a septum opening in one embodiment. FIG. 16 is a graph showing the relationship between the height of the oil level pooled on the lower side of the motor chamber and the area of the first region in a motor unit of one embodiment. FIG. 17 is a front view of a partition opening of a modified example. FIG. 18 is a graph showing the relationship between the surface area of the first region and the height of the oil level pooled on the lower side of the motor chamber in a motor unit provided with a partition wall opening of a modified example. FIG. 19 is a side view showing the arrangement of gears located inside a gear chamber in a motor unit according to one embodiment. FIG. 20 is a plan view of a parking mechanism that can be used in the motor unit of one embodiment. FIG. 21 is a partial cross-sectional view showing a motor unit separation mechanism of the first modified example. FIG. 22 is a conceptual diagram showing a state in which the motor and the reduction gear transmission are connected by a disconnecting mechanism. FIG. 23 is a conceptual diagram showing a state in which the motor and the reduction gear transmission are separated by the separation mechanism.

Below, a motor according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention. Also, in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each configuration easier to understand.

In the following explanation, the direction of gravity is defined based on the positional relationship when the motor unit 1 is mounted on a vehicle positioned on a horizontal road surface. In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system. In the XYZ coordinate system, the Z axis direction indicates the vertical direction (i.e., the up-down direction), the +Z direction is the upper side (opposite the direction of gravity), and the -Z direction is the lower side (direction of gravity). In addition, the X axis direction is perpendicular to the Z axis direction and indicates the front-to-rear direction of the vehicle on which the motor unit 1 is mounted, with the +X direction being the front of the vehicle and the -X direction being the rear of the vehicle. However, it is also possible that the +X direction is the rear of the vehicle and the -X direction is the front of the vehicle. The Y axis direction is perpendicular to both the X axis direction and the Z axis direction, and is the width direction (left-right direction) of the vehicle.

Unless otherwise specified in the following description, the direction parallel to the motor axis J2 of the motor 2 (Z-axis direction) will be referred to simply as the "axial direction", the radial direction centered on the motor axis J2 will be referred to simply as the "radial direction", and the circumferential direction centered on the motor axis J2, i.e., around the axis of the motor axis J2, will be referred to simply as the "circumferential direction". Furthermore, in the following description, "plan view" refers to a state viewed from the axial direction. However, the above "parallel direction" also includes a direction that is approximately parallel. Furthermore, the above "orthogonal direction" also includes a direction that is approximately orthogonal.

Below, a motor unit (electric drive device) 1 according to an exemplary embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of the motor unit 1 according to one embodiment. FIG. 2 is a perspective view of the motor unit 1. FIG. 3 is a side view of the motor unit 1. FIG. 4 is a cross-sectional view of the motor unit 1 taken along line IV-IV in FIG. 3. Note that part of the internal structure of the differential gear 5 has been omitted in FIG. 4.

The motor unit 1 is mounted on a vehicle that uses a motor as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as the power source.

As shown in FIG. 1, the motor unit 1 includes a motor (main motor) 2, a reduction gear 4, a differential gear 5, a housing 6, oil O, and an oil passage 90 that supplies the oil O to the motor 2. The motor unit 1 may also include a parking mechanism 7, as shown by the phantom line in FIG. 2.

As shown in FIG. 1, the motor 2 includes a rotor 20 that rotates around a motor shaft J2 extending in the horizontal direction, and a stator 30 located radially outside the rotor 20. The reduction gear 4 is connected to the rotor 20 of the motor 2. The differential gear 5 is connected to the motor 2 via the reduction gear 4. The housing 6 has an accommodation space 80 that accommodates the motor 2, the reduction gear 4, and the differential gear 5 inside. The oil O is used to lubricate the reduction gear 4 and the differential gear 5, and is also used to cool the motor 2. The oil O accumulates in the vertically lower region of the accommodation space 80. Since the oil O functions as a lubricating oil and a cooling oil, it is preferable to use an oil equivalent to a low-viscosity automatic transmission lubricating oil (ATF: Automatic Transmission Fluid). The oil passage 90 is a path for the oil O that supplies the oil O from the lower region of the accommodation space 80 to the motor 2. The oil passage 90 has a first oil passage 91 and a second oil passage 92.

In this specification, the term "oil passage" refers to the path of the oil O circulating in the storage space 80. Therefore, the term "oil passage" is a concept that includes not only a "flow path" that creates a steady flow of oil in one direction, but also a path that temporarily retains oil (e.g., a reservoir) and a path along which oil drips.

<Housing> The motor 2, reduction gear 4, and differential gear 5 are accommodated in the accommodation space 80 provided inside the housing 6. The housing 6 holds the motor 2, reduction gear 4, and differential gear 5 in the accommodation space 80. The housing 6 has a partition wall 61c. The accommodation space 80 of the housing 6 is divided into a motor chamber 81 and a gear chamber 82 by the partition wall 61c. The motor chamber 81 accommodates the motor 2. The gear chamber 82 accommodates the reduction gear 4 and differential gear 5.

An oil reservoir P in which oil O accumulates is provided in the lower region of the storage space 80. In this embodiment, the bottom 81a of the motor chamber 81 is located above the bottom 82a of the gear chamber 82. A partition opening 68 is provided in the lower region of the partition 61c that separates the motor chamber 81 from the gear chamber 82. The partition opening 68 connects the motor chamber 81 to the gear chamber 82. The partition opening 68 moves the oil O that accumulates in the lower region of the motor chamber 81 to the gear chamber 82. Therefore, in this embodiment, the oil reservoir P is provided in the lower region of the gear chamber 82.

A portion of the differential gear 5 is immersed in the oil sump P. The oil O that accumulates in the oil sump P is scooped up by the operation of the differential gear 5, with a portion of it being supplied to the first oil passage 91 and a portion being diffused into the gear chamber 82. The oil O that has diffused into the gear chamber 82 is supplied to each gear of the reduction gear 4 and the differential gear 5 in the gear chamber 82, spreading the oil O over the gear tooth surfaces. The oil O used in the reduction gear 4 and the differential gear 5 drips down and is collected in the oil sump P located below the gear chamber 82. The capacity of the oil sump P in the accommodation space 80 is set so that a portion of the bearings of the differential gear 5 are immersed in the oil O when the motor unit 1 is stopped.

The housing 6 is made of, for example, aluminum die casting. The housing 6 forms the outer frame of the motor unit 1. The housing 6 has a motor accommodating section 61, a gear accommodating section 62, and a closing section 63. The gear accommodating section 62 is located on the left side of the motor accommodating section 61. The closing section 63 is located on the right side of the motor accommodating section 61.

The motor housing 61 has a cylindrical peripheral wall 61a that surrounds the motor 2 from the radial outside, and a side plate 61b located on one axial side of the peripheral wall 61a. The space inside the peripheral wall 61a forms the motor chamber 81. The side plate 61b has a partition 61c and a protruding plate 61d. The partition 61c covers the opening on one axial side of the peripheral wall 61a. In addition to the partition opening 68 described above, the partition 61c has an insertion hole 61f through which the shaft 21 of the motor 2 is inserted. The side plate 61b has a partition 61c and a protruding plate 61d that protrudes radially outward from the peripheral wall 61a. The protruding plate 61d has a first axle passage hole 61e through which a drive shaft (not shown) that supports the wheels passes.

The closing portion 63 is fixed to the motor housing portion 61.
1a. That is, the blocking portion 63 blocks the opening on the axially opposite side of the motor accommodating portion 61. The blocking portion 63 has a blocking portion main body 63a and a lid member 63b. The blocking portion main body 63a has a cylindrical protruding portion 63d that protrudes into the accommodation space 80 located inside the motor accommodating portion 61. The protruding portion 63d extends along the inner circumferential surface of the peripheral wall portion 61a. In addition, the blocking portion main body 63a is provided with a window portion 63c that penetrates in the axial direction. The lid member 63b blocks the window portion 63c from the outside of the accommodation space 80.

The gear accommodating portion 62 is fixed to the side plate portion 61b of the motor accommodating portion 61. The gear accommodating portion 62 has a concave shape that opens toward the side plate portion 61b. The opening of the gear accommodating portion 62 is covered by the side plate portion 61b. The space between the gear accommodating portion 62 and the side plate portion 61b forms a gear chamber 82 that accommodates the reduction gear 4 and the differential gear 5. A second axle passage hole 62e is provided in the gear accommodating portion 62. The second axle passage hole 62e overlaps with the first axle passage hole 61e when viewed in the axial direction.

As shown in FIG. 3, the gear accommodating portion 62 has a first reservoir (reservoir) 93 and a shaft supply passage 94. The first reservoir 93 is located on a surface of the gear accommodating portion 62 facing the gear chamber 82 in the axial direction, and extends along the axial direction. The first reservoir 93 receives the oil O scooped up by the differential device 5. The shaft supply passage 94 extends from the bottom of the first reservoir 93 toward the shaft 21 of the motor 2. The shaft supply passage 94 is a passage that supplies the oil O received in the first reservoir 93 to the inside of the hollow portion 22 of the shaft 21.

<Reduction Gear> As shown in FIG. 4, the reduction gear 4 has the function of reducing the rotational speed of the motor 2 and increasing the torque output from the motor 2 according to the reduction ratio. The reduction gear 4 transmits the torque output from the motor 2 to the differential gear 5.

The reduction gear 4 has a first gear (intermediate drive gear) 41, a second gear (intermediate gear) 42, a third gear (primary drive gear) 43, and an intermediate shaft 45. The torque output from the motor 2 is transmitted to the ring gear (gear) 51 of the differential device 5 via the shaft 21 of the motor 2, the first gear 41, the second gear 42, the intermediate shaft 45, and the third gear 43. The gear ratio of each gear and the number of gears can be changed in various ways depending on the required reduction ratio. The reduction gear 4 is a parallel shaft gear type reducer in which the axes of the gears are arranged in parallel.

The first gear 41 is provided on the outer circumferential surface of the shaft 21 of the motor 2. The first gear 41 rotates together with the shaft 21 around the motor axis J2.

The intermediate shaft 45 extends along an intermediate axis J4 that is parallel to the motor shaft J2. The intermediate shaft 45 has a cylindrical shape centered on the intermediate axis J4. The intermediate shaft 45 rotates around the intermediate axis J4. The intermediate shaft 45 is rotatably supported by a pair of intermediate shaft retaining bearings 87. One of the pair of intermediate shaft retaining bearings 87 is held on the surface of the partition wall 61c that faces the gear chamber 82. The other of the pair of intermediate shaft retaining bearings 87 is held in the gear accommodating portion 62.

The second gear 42 and the third gear 43 are provided on the outer circumferential surface of the intermediate shaft 45. The second gear 42 and the third gear 43 are connected via the intermediate shaft 45. The second gear 42 and the third gear 43 rotate around the intermediate shaft J4. The second gear 42 meshes with the first gear 41. The third gear 43 meshes with the ring gear 51 of the differential device 5. The third gear 43 is located on the partition wall 61c side relative to the second gear 42. In this embodiment, the intermediate shaft 45 and the third gear 43 are a single member.

<Differential gear> The differential gear 5 is a device for transmitting the torque output from the motor 2 to the wheels of the vehicle. The differential gear 5 has the function of transmitting the same torque to the axles 55 of both the left and right wheels while absorbing the speed difference between the left and right wheels when the vehicle turns. The differential gear 5 has a ring gear 51, a gear housing 57, a pair of pinion gears (not shown), a pinion shaft (not shown), and a pair of side gears (not shown).

The ring gear 51 rotates around a differential shaft J5 that is parallel to the motor shaft J2. The torque output from the motor 2 is transmitted to the ring gear 51 via the reduction gear 4. In other words, the ring gear 51 is connected to the motor 2 via other gears. The ring gear 51 is fixed to the outer periphery of the gear housing 57.

The gear housing 57 houses a pair of pinion gears and a pair of side gears. When torque is transmitted to the ring gear 51, the gear housing 57 rotates together with the ring gear 51 around the differential shaft J5. The pair of pinion gears are bevel gears that face each other. The pair of pinion gears are supported by a pinion shaft. The pair of side gears are bevel gears that mesh with the pair of pinion gears at right angles. Each of the pair of side gears has a fitting portion. An axle is fitted into each of the fitting portions. The pair of axles fitted into different fitting portions rotate with the same torque around the differential shaft J5.

<Motor> As shown in FIG. 4, the motor 2 is an inner rotor type motor that includes a stator 30 and a rotor 20 that is rotatably arranged inside the stator 30. The rotor 20 rotates when power is supplied to the stator 30 from a battery (not shown). The torque of the motor 2 is transmitted to the differential device 5 via the reduction gear 4.

(Stator) The stator 30 has a stator core 32, a coil 31, and an insulator (not shown) interposed between the stator core 32 and the coil 31. The stator 30 is held in the housing 6.

The stator core 32 has multiple magnetic pole teeth (not shown) extending radially inward from the inner circumferential surface of the annular yoke. In this embodiment, the stator core 32 has 48 slots formed between the magnetic pole teeth. The coil 31 is formed by wrapping a coil wire between the magnetic pole teeth.

The coil 31 has coil ends 31a that protrude from the axial end face of the stator core 32. That is, the stator 30 has coil ends 31a. The coil ends 31a protrude in the axial direction beyond the ends of the rotor core 24 of the rotor 20. The coil ends 31a protrude on both axial sides of the rotor core 24.

(Rotor) The rotor 20 has a shaft (motor shaft) 21, a rotor core 24, a rotor magnet (permanent magnet) 25, a pair of plate-shaped end plates 26, a nut 29, and a washer (cover) 28.

(Shaft) The shaft 21 extends around the motor axis J2, which extends horizontally and in the width direction of the vehicle (perpendicular to the direction of travel of the vehicle). The shaft 21 has a first shaft portion 21A and a second shaft portion 21B that are coaxially connected to each other.

The shaft 21 is a hollow shaft with a hollow section 22 therein having an inner circumferential surface extending along the motor axis J2. The hollow section 22 includes a first hollow section 22A located inside the first shaft section 21A and a second hollow section 22B located inside the second shaft section 21B. The first hollow section 22A and the second hollow section 22B are aligned along the axial direction and communicate with each other.

The first shaft portion 21A is disposed in the motor chamber 81 of the accommodation space 80. The first shaft portion 21A is located radially inside the stator 30 and passes through the rotor core 24 along the motor axis J2. The first shaft portion 21A has a first end portion 21e located on the output side (i.e., the reduction gear 4 side) and a second end portion 21f located on the opposite side.

The first shaft portion 21A is supported for free rotation by a pair of first bearings 89. The pair of first bearings 89 support the first end 21e and the second end 21f of the first shaft portion 21A. One of the pair of first bearings 89 is held in the blocking portion 63. The other of the pair of first bearings 89 is held on the surface of the partition wall 61c facing the motor chamber 81.

Figure 5 is a cross-sectional view of the rotor 20. In Figure 5, the second shaft portion 21B is shown by a virtual line. The first shaft portion 21A is provided with a pair of communication holes 23. The communication holes 23 extend in the radial direction to connect the outside of the shaft 21 with the hollow portion 22. That is, the shaft 21 is provided with a pair of communication holes 23. The pair of communication holes 23 are aligned along the axial direction. In this specification, a hole that extends from the outer peripheral surface of the shaft 21, passes through the hollow portion, and reaches the outer peripheral surface is considered to be one communication hole 23.

The outer peripheral surface of the first shaft portion 21A is provided with a flange portion (lid portion) 21c and a threaded portion 21d aligned along the axial direction. That is, the outer peripheral surface of the shaft 21 is provided with the flange portion 21c and the threaded portion 21d. The rotor core 24 is located between the flange portion 21c and the threaded portion 21d in the axial direction. A nut 29 is fastened to the threaded portion 21d.

As shown in FIG. 4, the second shaft portion 21B is positioned coaxially with the first shaft portion 21A. The second shaft portion 21b has a third end 21g positioned on the first shaft portion 21A side and a fourth end 21h positioned on the opposite side. The second shaft portion 21B is connected to the first end 21e of the first shaft portion 21A at the third end 21g.

The second shaft portion 21B is disposed in the gear chamber 82 of the accommodation space 80. The third end 21g of the second shaft portion 21B protrudes toward the motor chamber 81 through an insertion hole 61f provided in the partition wall 61c and is connected to the first shaft portion 21A. A first gear 41 is provided on the outer circumferential surface of the second shaft portion 21B. The first gear 41 is part of the reduction gear 4. The first gear 41 meshes with the second gear 42 and transmits the output of the shaft 21 to the second gear.

The second shaft portion 21B is rotatably supported by a pair of second bearings 88. One of the pair of second bearings 88 is held on the surface of the partition wall 61c facing the gear chamber 82. The other of the pair of second bearings 88 is held in the gear housing portion 62.

The hollow portion 22 opens in the axial direction at the second end 21f of the first shaft portion 21A and the fourth end 21h of the second shaft portion 21B. Oil O is supplied to the hollow portion 22 from the opening of the fourth end 21h. The oil O supplied to the hollow portion 22 flows from the fourth end 21h side toward the second end 21f side. The oil O supplied to the hollow portion 22 flows out to the outside of the shaft 21 through the communication hole 23. In the following description, the fourth end 21h side may be referred to as the upstream side of the hollow portion 22 in the flow direction, and the second end 21f side may be referred to as the downstream side of the hollow portion 22 in the flow direction.

As shown in FIG. 5, the first hollow portion 22A has a first region 22p, a second region (small diameter hollow portion) 22q, and a third region (large diameter hollow portion) 22r, which have different diameters of the inner circumferential surface. The first region 22p, the second region 22q, and the third region 22r have larger diameters of the inner circumferential surface in this order. That is, the second region 22q has a larger inner diameter than the first region 22p, and the third region 22r has a larger inner diameter than the first region 22p and the third region 22r. The first region 22p, the second region 22q, and the third region 22r are arranged in this order from the downstream side to the upstream side in the flow direction. The first region 22p is located on the second end 21f side. The second region 22q is located between the first region 22p and the third region 22r in the axial direction. The third region 22r is located on the first end 21e side. That is, the third region 22r is located closer to the second shaft portion 21B than the second region 22q.

In the third region 22r, one of the pair of communication holes 23, which is on the upstream side in the flow direction, opens. In addition, in the second region 22q, the other of the pair of communication holes 23, which is on the downstream side in the flow direction, opens.

The inner peripheral surface of the first hollow portion 22A has a first step surface 22s located between the first region 22p and the second region 22q, and a second step surface (step surface) 22t located between the second region 22q and the third region 22r.
The first step surface 22s and the second step surface 22t face the second shaft portion 21B. The first step surface 22s and the second step surface 22t are inclined toward the upstream side in the flow direction as they extend radially outward.

The third end 21g of the second shaft portion 21B is inserted into the third region 22r of the first shaft portion 21A. A female spline 22e is provided in the third region 22r. Meanwhile, a male spline 22g is provided on the outer circumferential surface of the third end 21g of the second shaft portion 21B. The female spline 22e and the male spline 22g fit together. This connects the first shaft portion 21A and the second shaft portion 21B.

A gap is provided between the end face of the second shaft portion 21B facing the first shaft portion 21A (i.e., the end face of the third end portion 21g) and the second step surface 22t. The gap between the end face of the third end portion 21g and the second step surface 22t forms a groove 22u on the inner peripheral surface of the hollow portion 22. That is, a groove 22u extending along the circumferential direction is provided on the inner peripheral surface of the hollow portion 22, and the groove 22u is composed of the end face of the third end portion 21g of the second shaft portion 21B, the inner peripheral surface of the third region 22r, and the second step surface 22t.

Of the pair of communication holes 23, one communication hole 23 located upstream in the flow direction of the oil O opens into the hollow portion 22 at the groove 22u. Centrifugal force is applied to the oil O supplied into the hollow portion 22 as the shaft 21 rotates. Since the groove 22u is provided on the inner peripheral surface of the hollow portion 22, the oil O accumulates in the groove 22u due to the centrifugal force. According to this embodiment, since the communication hole 23 opens into the groove 22u, the oil O accumulated in the groove 22u can be efficiently guided to the communication hole 23.

According to this embodiment, the gap at the connection between the first shaft portion 21A and the second shaft portion 21B can be used as a groove 22u to store oil O. Therefore, there is no need to perform special processing to provide the groove 22u for storing oil O.

When multiple communication holes 23 are arranged along the axial direction, oil O tends to flow into the communication holes 23 located downstream in the flow direction of the oil O, and there may be a shortage of oil O flowing into the communication holes 23 upstream in the flow direction of the oil O. According to this embodiment, the communication holes 23 located upstream in the flow direction open in the recessed groove 22u, so that the oil O can be made to flow sufficiently into the communication holes 23 located upstream in the flow direction.

According to this embodiment, the diameter of the hollow portion 22 gradually decreases from the upstream side to the downstream side in the flow direction. This makes it easier for oil O to spread from the upstream side to the downstream side of the hollow portion 22. In addition, one of the pair of communication holes 23 on the upstream side opens into the third region 22r, and the other on the downstream side opens into the second region 22q. In other words, the opening of the downstream communication hole 23 is provided in an area of the hollow portion 22 with a smaller diameter than the opening of the upstream communication hole 23. Therefore, oil O can be sufficiently allowed to flow into the communication hole 23 located on the downstream side.

A part of the female spline 22e is located in the gap between the end face of the third end 21g and the second step surface 22t. Therefore, the inner surface of the hollow portion 22 has convex and concave portions arranged along the circumferential direction due to the female spline 22e. If the cross-sectional shape of the hollow portion is a circle centered on the motor shaft, there is a risk that the oil O in the hollow portion will rotate freely relative to the shaft even when the shaft rotates, and centrifugal force will not be applied to the oil O. In contrast, by providing convex and concave portions arranged along the circumferential direction in the hollow portion 22, the oil O can be rotated with the rotation of the shaft 21, and centrifugal force can be applied to the oil O in the hollow portion 22. This allows the oil O to be smoothly guided to the communication hole 23.

According to this embodiment, the outer peripheral surface of the second shaft portion 21B and the inner peripheral surface of the third region 22r are provided with splines (male spline 22g and female spline 22e) that fit into each other. In addition, a portion of the spline (female spline 22e) of the third region 22r is located within the recessed groove 22u. Therefore, centrifugal force can be applied to the oil O in the hollow portion 22 by utilizing the female spline 22e used for the fit. In other words, there is no need to process the inner peripheral surface of the hollow portion 22 to create an uneven shape in order to apply centrifugal force to the oil O.

(Rotor core) The rotor core 24 is constructed by laminating silicon steel plates. The rotor core 24 is a cylindrical body extending along the axial direction. The rotor core 24 has a pair of axial end faces 24a facing opposite sides in the axial direction, and an outer peripheral surface 24b facing radially outward.

The rotor core 24, together with a pair of end plates 26, is sandwiched between the nut 29 and the flange portion 21c. A washer 28 is interposed between the nut 29 and the end plate 26.

The rotor core 24 is provided with one fitting hole 24c that is located in the center when viewed from the axial direction and penetrates along the axial direction, multiple magnet holding holes 24d, and multiple core through holes 24e. The fitting hole 24c, magnet holding holes 24d, and core through holes 24e open to a pair of axial end faces 24a.

The fitting hole 24c is circular and centered on the motor shaft J2. The shaft 21 is inserted and fitted into the fitting hole 24c. Thus, the rotor core 24 surrounds the shaft 21 from the radial outside. The shaft 21 is fitted into the fitting hole 24c with a clearance fit. Therefore, deformation of the rotor core 24 due to the fitting of the shaft 21 is suppressed. A protrusion (not shown) that protrudes radially inward is provided on the inner surface of the fitting hole 24c. This protrusion fits into a key groove (not shown) provided on the outer surface of the shaft 21. This prevents relative rotation between the rotor core 24 and the shaft 21.

The multiple core through holes 24e are arranged in a line along the circumferential direction. The core through holes 24e are located radially inward from the magnet holding holes 24d. The core through holes 24e serve to allow oil O to flow between the pair of axial end faces 24a.

The multiple magnet holding holes 24d are arranged in a line along the circumferential direction. The rotor magnets 25 are inserted into the magnet holding holes 24d. The magnet holding holes 24d hold the rotor magnets 25. In other words, the rotor 20 of this embodiment is an embedded type (IPM (interior permanent magnet)) in which the rotor magnets 25 are embedded inside the rotor core 24.

The rotor magnet 25 is a permanent magnet. The multiple rotor magnets 25 are inserted into multiple magnet retaining holes 24d that are aligned in the circumferential direction and fixed to the rotor core 24. The multiple rotor magnets 25 are aligned in the circumferential direction.

(End plate) Figure 6 is a plan view of the end plate 26. Figure 7 is a cross-sectional view of the end plate 26 taken along line VII-VII in Figure 6. Note that in Figures 6 and 7, other members of the motor unit 1 are shown by virtual lines.

As shown in FIG. 6, the end plate 26 is circular in plan view. The end plate 26 is a metal plate. The end plate 26 has a circular central hole 26i that penetrates along the axial direction. A key portion 26q is provided on the inner peripheral surface of the central hole 26i. The key portion 26q fits into a key groove 21k provided in the shaft 21. The end plate 26 and the shaft 21 are prevented from rotating relative to each other by the engagement of the key portion 26q with the key groove 21k.

As shown in FIG. 5, the end plate 26 has a first surface 26a and a second surface 26b. The first surface 26a faces the axial end surface 24a of the rotor core 24. The second surface 26b faces the opposite side to the first surface 26a.

The pair of end plates 26 are located on both axial sides of the rotor core 24. The pair of end plates 26 contact the pair of axial end faces 24a of the rotor core 24, respectively. One of the pair of end plates 26 (first end plate 26A) is located between one of the axial end faces 24a of the rotor core 24 and the flange portion 21c. The other of the pair of end plates 26 (second end plate 26B) is located between the other axial end face 24a of the rotor core 24 and the washer 28. The end plate 26 contacts the axial end face 24a at the first surface 26a. The end plate 26 contacts the flange portion 21c or the washer 28 at the second surface 26b.

According to this embodiment, the rotor core 24 and the pair of end plates 26 are sandwiched between the flange portion 21c and the nut 29. As a result, the pair of end plates 26 are pressed against the axial end surface 24a of the rotor core 24 from both axial sides. A frictional force is generated at the contact portion between the first surface 26a of the end plate 26 and the axial end surface 24a of the rotor core 24, which can suppress the relative rotation between the rotor core 24 and the shaft 21. When the rotor core and the shaft are fixed by press-fitting, the rotor core is deformed, the magnetic path passing through the rotor core changes, and iron loss increases. In particular, in a motor for driving a vehicle as in this embodiment, since the driving force is large, it is necessary to ensure a large tightening margin for press-fitting, and iron loss of the rotor core is likely to increase. According to this embodiment, the rotor core 24 is fixed to the shaft 21 via the end plate 26. Therefore, the fitting hole 24c of the rotor core 24 and the shaft 21 can be fitted with a clearance fit, which can suppress deformation of the rotor core 24 and provide a highly efficient motor 2.

As shown in FIG. 7, the first surface 26a is provided with a recess 26f and an inclined surface 26e surrounding the recess 26f from the radial outside. The recess 26f is circular in plan view, centered on the motor shaft J2. The recess 26f has a recess bottom surface 26g and a recess inner circumferential surface 26h. The recess bottom surface 26g is a plane perpendicular to the motor shaft J2. The recess inner circumferential surface 26h is located between the recess bottom surface 26g and the inclined surface 26e. The recess inner circumferential surface 26h is inclined in a direction that makes the recess 26f shallower as it goes from the radial inside to the radial outside. A gap is provided between the recess 26f and the axial end surface 24a of the rotor core 24. Oil O accumulates in this gap and cools the axial end surface 24a of the rotor core 24.

The inclined surface 26e is provided in the radially outermost region of the first surface 26a and extends along the circumferential direction. As the inclined surface 26e moves radially outward, it inclines toward the rotor core 24 at an inclination angle θ. Note that the inclination angle θ is the angle between the inclined surface 26e and a plane perpendicular to the motor shaft J2.

The end plate 26 contacts the axial end face 24a of the rotor core 24 at the inclined surface 26e of the first surface 26a. Since the inclined surface 26e inclines toward the rotor core 24 as it moves radially outward, the inclined surface 26e contacts the axial end face 24a in the radially outermost region. This allows the frictional force generated by the contact between the inclined surface 26e and the axial end face 24a to be generated as radially outward as possible. In addition, the normal stress between the inclined surface 26e and the axial end face 24a can be increased as it moves radially outward. This allows the limit value of the static frictional force to be increased as it moves radially outward. The holding torque that suppresses the relative rotation between the end plate 26 and the rotor core 24 is proportional to the distance from the rotation axis and the frictional force. Therefore, according to this embodiment, the holding torque that suppresses the relative rotation between the end plate 26 and the rotor core 24 can be increased, and the rotor core 24 can be firmly held against the end plate 26. To achieve this effect, it is preferable that the inclination angle θ of the inclined surface 26e be greater than or equal to 0.1° and less than or equal to 5°.

In addition, the end plate 26 of this embodiment contacts the axial end face 24a of the rotor core 24 at the inclined surface 26e. This makes it possible to stabilize the contact position between the end plate 26 and the rotor core 24. This makes it possible to suppress variation in the torque transmitted between the end plate 26 and the rotor core 24, and ensures that the rotor core 24 is fixed reliably to the shaft 21.

According to the present embodiment, the end plate 26 is provided with the inclined surface 26e, so that the end plate 26 and the axial end surface 24a of the rotor core 24 can be reliably contacted even if the flatness of the contact portion between the end plate 26 and the axial end surface 24a of the rotor core 24 varies. As described later, an oil flow path 26t (see FIG. 5) is provided on the radial inner side of the inclined surface 26e. Generally, when oil infiltrates between the rotor core and the stator, the rotation efficiency of the rotor core decreases. The inclined surface 26e contacts the axial end surface 24a of the rotor core 24, so that the oil O in the oil flow path 26t can be prevented from infiltrating from between the end plate 26 and the rotor core 24 into the gap between the outer circumferential surface 24b of the rotor core 24 and the stator 30. The inclined surface 26e may be configured such that the inclination angle changes as it moves radially outward. The inclined surface 26e may also be a curved surface whose inclination angle changes as it moves radially outward.

As shown in FIG. 5, the inclined surface 26e blocks the opening of the magnet holding hole 24d of the rotor core 24. This prevents the rotor magnet 25 held inside the magnet holding hole 24d from popping out of the opening of the magnet holding hole 24d. This prevents a part of the rotor magnet 25 from penetrating into the drive portion inside the housing recess.

As shown in FIG. 7, the second surface 26b has a flat surface 26c and a chamfered portion 26d located on the outer edge of the flat surface 26c. The flat surface 26c is perpendicular to the motor axis J2. The chamfered portion 26d is inclined toward the first surface 26a as it moves radially outward.

As shown in FIG. 5, the end plate 26 has two sets of plate through holes 26p, first grooves (first recesses) 26j, and second grooves (second recesses) 26k. Below, one of the two sets of plate through holes 26p, first grooves 26j, and second grooves 26k will be described, but the other set has a similar configuration.

The plate through hole 26p extends along the axial direction. The first groove 26j is located on the first surface 26a. The first groove 26j extends radially inward from the opening of the plate through hole 26p. The first groove 26j opens radially inward at the inner circumferential surface of the central hole 26i. The second groove 26k is located on the second surface 26b. The second groove 26k extends radially outward from the opening of the plate through hole 26p. The second groove 26k opens radially outward at the chamfered portion 26d.

The axial opening of the first groove 26j of the end plate 26 is covered by the axial end face 24a of the rotor core 24. The radial opening of the first groove 26j is connected to the communication hole 23 of the shaft 21.

Oil O supplied to the inside of the hollow portion 22 of the shaft 21 flows radially outward through the communication hole 23. The oil O also flows into the first groove 26j from the radially outer opening of the communication hole 23. The oil O then passes through the plate through hole 26p and flows toward the first surface 26a and the second surface 26b, and is discharged to the outside of the rotor 20 through the second groove 26k. As shown in FIG. 4, the coil end 31a of the stator 30 is provided on the radially outer side of the end plate 26. The oil O discharged to the outside of the rotor 20 is supplied to the coil end 31a and cools the coil end 31a.

The first groove 26j, the plate through hole 26p, and the second groove 26k of the end plate 26 function as an oil flow path 26t. That is, the oil flow path 26t is composed of the first groove 26j, the plate through hole 26p, and the second groove 26k. Each of the pair of end plates 26 is provided with an oil flow path 26t that communicates with the communication hole 23, extends along the radial direction, and opens.

In the end plate 26 of this embodiment, the plate through hole 26p, the first groove 26j, and the second groove 26k form the oil flow path 26t. Therefore, in this embodiment, the oil flow path 26t can be formed by an inexpensive part (end plate 26) manufactured by die molding.

The core through hole 24e communicates with the first grooves 26j of the pair of end plates 26. That is, the core through hole 24e connects the first grooves 26j of each of the pair of end plates 26. In other words, the core through hole 24e connects the oil flow paths 26t of each of the pair of end plates 26. In addition, at least a portion of the opening of the core through hole is located radially outward from the plate through hole 26p.

In this embodiment, the core through hole 24e connects the first grooves 26j of the pair of end plates 26, so that a portion of the oil O passing through the first groove 26j can flow into the core through hole 24e. This allows the oil O in the core through hole 24e to cool the rotor core 24 from the inside. In addition, the rotor magnet 25 held in the rotor core 24 can be cooled via the rotor core 24.

According to this embodiment, the opening of the core through hole 24e is located radially outward from the plate through holes 26p of the pair of end plates 26. This allows oil O to be stored inside the core through hole 24e by the centrifugal force of the rotor 20, and oil O can be supplied from the core through hole 24e to the first grooves 26j of the end plates 26 on both sides. Also, when there is a shortage of oil O in the first grooves 26j on one side of the pair of end plates 26, oil O can be supplied from the other side via the core through hole 24e. Therefore, it is possible to release approximately the same amount of oil O from each end plate 26 to the coil end 31a, enabling stable cooling of the coil 31.

As shown in FIG. 5, of the pair of end plates 26, one sandwiched between the flange portion 21c and the rotor core 24 is the first end plate 26A, and the other sandwiched between the nut 29 and the rotor core 24 is the second end plate 26B.

In the first end plate 26A, a portion of the radially inner side of the plate through hole 26p is covered by the flange portion 21c. In addition, in the first end plate 26A, the axial opening of the second groove 26k faces the axially outer side in its entirety. In other words, in the first end plate 26A, the axial opening of the second groove 26k is entirely exposed when viewed from the axial direction. That is, the second groove 26k of the first end plate 26A communicates with the outside at the opening facing the axial direction. In the first end plate 26A, the second groove 26k functions as a first opening 26s that is released from the washer 28, with a portion of the plate through hole 26p and the entire opening facing the axial direction. In the first end plate 26A, the oil O that passes through the plate through hole 26p is released from the first opening 26s.

A washer 28 is interposed between the second end plate 26B and the nut 29. In the second end plate 26B, a portion of the radially inner side of the plate through hole 26p and the opening facing the axial direction of the second groove 26k is covered by the washer 28. Of the opening facing the axial direction of the second groove 26k, the portion covered by the washer 28 is called the covered portion, and the portion not covered by the washer 28 is called the open portion. That is, in the second end plate 26B, the opening facing the axial direction of the second groove 26k has a covered portion covered by the washer 28 and a second open portion 26r not covered by the washer. The second groove 26k of the second end plate 26B faces the axially outer side at the second open portion 26r located at the radially outer end of the second groove 26k. In other words, the second groove 26k of the second end plate 26B is exposed at the second open portion 26r when viewed from the axial direction. That is, the second groove 26k of the second end plate 26B is connected to the outside at the second open portion 26r. The second open portion 26r is located at the radially outer end of the second groove 26k. In the second end plate 26B, the oil O that passes through the plate through hole 26p is released from the second open portion 26r.

In the first end plate 26A and the second end plate 26B of this embodiment, the second groove 26k is provided on the second surface 26b, so that the oil O flowing to the second surface 26b side through the plate through hole 26p can be moved radially outward along the second groove 26k. Therefore, the oil O can be stably flowed to the second open portion 26r, and the oil O can be stably supplied to the coil end 31a of the stator 30.

According to this embodiment, the flange 21c or washer 28 functions as a lid covering the axial opening of the second groove 26k of the first end plate 26A and the second end plate 26B. That is, the rotor 20 has a pair of lids (flange 21c and washer 28) located at the axial end of the rotor core 24 via the end plate 26. The lids (flange 21c and washer 28) cover the axial opening of the plate through hole 26p from the outside, thereby guiding the oil O flowing out from the plate through hole 26p to the second surface 26b side to flow along the second groove 26k. According to this embodiment, the behavior of the oil O can be controlled by the lids (flange 21c and washer 28) to prevent the oil O from penetrating between the rotor core 24 and the stator 30.

According to the second end plate 26B of this embodiment, the opening of the second groove 26k facing the axial direction is partially covered by the washer 28 and faces the axially outer side at the second open portion 26r. That is, in the region of the second groove 26k leading to the second open portion 26r, the oil O does not overflow in the axial direction, and the oil O can be reliably moved to the second open portion 26r. This allows the oil O to be stably released from the second open portion 26r, and the oil O can be stably supplied to the coil end 31a.

According to this embodiment, the second groove 26k faces the axially outer side at the second open portion 26r located at the radial end. Therefore, the oil O that passes through the second groove 26k can be scattered in the axial direction from the second open portion 26r. This allows the oil O to be scattered toward the coil end 31a that protrudes in the axial direction beyond the end of the rotor core 24, and the coil 31 of the coil end 31a can be effectively cooled.

In the first end plate 26A of this embodiment, the first opening 26s is provided over a portion of the plate through hole 26p and the entire opening facing the axial direction. However, as shown by the imaginary line in FIG. 5, the flange portion 21c may cover a portion of the opening facing the axial direction of the second groove 26k. In this case, the first opening 26s of the first end plate 26A is located at the radially outer end, similar to the second opening 26r of the second end plate 26B, and can achieve the same effect as the second opening 26r.

In this embodiment, the end plate 26 is provided with a groove-shaped first recessed groove 26j and a second recessed groove 26k. However, even recesses that are not groove-shaped can achieve the same effect as described above. By providing the first recessed groove 26j and the second recessed groove 26k that extend in the radial direction, the oil O can be smoothly guided in the radial direction.

(First Modified End Plate) FIG. 8 is a cross-sectional view of an end plate 126 of a first modified example that can be employed in this embodiment. Note that components that are the same as those in the above-described embodiment will be described using the same reference numerals. As in the above-described embodiment, the end plate 126 of the first modified example has a first surface 126a that faces the rotor core 24 and a second surface 126b that faces the opposite side to the first surface 126a. The end plate 126 is also provided with a pair of plate through holes 126p, a pair of first grooves 126j, and a pair of second grooves 126k. The plate through holes 126p extend in the axial direction. The first grooves 126j are located in the first surface 126a. The first grooves 126j extend radially inward from the plate through holes 126p. The second grooves 126k are formed in the end plate 126. The plate through holes 126p extend in the axial direction. The first grooves 126j are located in the first surface 126a. The second grooves 126k extend radially inward from the plate through holes 126p.
The groove 126k is located on the second surface 126b. The second groove 126k extends radially outward from the plate through hole 126p. The opening of the second groove 126k facing the axial direction is partially covered by a lid portion 128 and faces axially outward at an open portion 126r. Note that the lid portion 128 is the washer 28 or the flange portion 21c (see FIG. 5).

In this modified example, the bottom of the second groove 126k is provided with an inclined surface 126u, which reduces the depth of the second groove 126k as it moves radially outward. The inclined surface 126u overlaps with the open portion 126r when viewed from the axial direction. According to this modified example, by providing the inclined surface 126u in the second groove 126k, an axial component can be imparted to the flow of the oil O. The oil O can be scattered in the axial direction, and can be effectively scattered toward the coil end 31a that protrudes axially beyond the end of the rotor core 24.

(Second modified end plate) Figure 9 is a plan view of an end plate 226 of a second modified example that can be used in this embodiment. Note that components that are the same as those in the above-mentioned embodiment will be described using the same reference numerals. The end plate 226 of the second modified example has a first surface 226a and a second surface 226b facing the opposite side to the first surface 226a, as in the above-mentioned embodiment. The end plate 226 also has a pair of plate through holes 226p, a pair of first grooves 226j, and a pair of second grooves 226k. The plate through holes 226p extend in the axial direction. The first grooves 226j are located on the first surface 226a. The first grooves 226j extend radially inward from the plate through holes 226p. The second grooves 226k are located on the second surface 226b. The second groove 226k extends radially outward from the plate through hole 226p. The axial opening of the second groove 226k is partially covered by the lid portion 228 and faces the axially outward at the open portion 226r. Note that the lid portion 228 is a washer 28 or a flange portion 21c (see FIG. 5).

The second groove 226k is a groove that extends along the radial direction. Also, when viewed from the axial direction, the direction in which the second groove 226k extends is inclined relative to the radial direction. Also, the second groove 226k curves so that the inclination angle relative to the radial direction increases as it moves radially outward. According to this modified example, since the second groove 226k is inclined relative to the radial direction, centrifugal force can be applied to the oil O passing through the second groove 226k from the inclined wall surface of the second groove 226k. This can increase the speed of the oil O scattering from the open portion 226r, and ensure that the oil O hits the coil end 31a even if the distance to the coil end 31a is long.

The pair of second grooves 226k in this modified example have different shapes when viewed from the axial direction. One of the pair of second grooves 226k, the second groove 226kA, is curved slightly in the axial direction compared to the other second groove 226kB, and has a small inclination angle with respect to the radial direction. That is, according to this embodiment, the extension direction of each of the multiple second grooves 226kA, 226kB when viewed from the axial direction has a different angle with respect to the radial direction. Therefore, the magnitude of the centrifugal force applied to the oil O by the pair of second grooves 226kA, 226kB is different from each other. Compared to the oil O scattered from one second groove 226kA, the oil O scattered from the other second groove 226kB is faster and scattered over a farther range. In other words, according to this modified example, the oil O can be scattered in different areas in the multiple second grooves 226kA and 226kB, allowing the oil O to be applied over a wide range of the coil end 31a.

<Oil passage> As shown in FIG. 1, the oil passage 90 is located inside the housing 6, i.e., in the accommodation space 80. The oil passage 90 is configured to span the motor chamber 81 and the gear chamber 82 of the accommodation space 80. The oil passage 90 is a path for the oil O that leads the oil O from the oil reservoir P (i.e., the area below the accommodation space 80) through the motor 2 and back to the oil reservoir P. The oil passage 90 has a first oil passage (oil passage) 91 that passes through the inside of the motor 2 and a second oil passage (oil passage) 92 that passes through the outside of the motor 2. The oil O cools the motor 2 from the inside and outside in the first oil passage 91 and the second oil passage 92. The oil passage 90 constitutes an oil cooling mechanism.

The first oil passage 91 and the second oil passage 92 are both paths that supply oil O from the oil reservoir P to the motor 2 and then collect the oil back into the oil reservoir P. In the first oil passage 91 and the second oil passage 92, the oil O drips from the motor 2 and accumulates in the area below the motor chamber 81. The oil O that accumulates in the area below the motor chamber 81 moves through the partition opening 68 to the area below the gear chamber 82 (i.e., the oil reservoir P).

A cooler 97 for cooling the oil O is provided in the first oil passage 91. The oil O that passes through the first oil passage 91 and is cooled by the cooler 97 merges with the oil O that passes through the second oil passage 92 in the oil sump P. In the oil sump P, the oil O that passes through the first oil passage 91 and the second oil passage 92 mix with each other and heat exchange occurs. Therefore, the cooling effect of the cooler 97, which is disposed in the first oil passage 91, can also be applied to the oil O that passes through the second oil passage 92. According to this embodiment, the oil O in both oil passages is cooled using one cooler 97 provided in one of the first oil passage 91 and the second oil passage 92.

Generally, a cooler is placed in a flow path through which liquid flows steadily. In order to cool two oil paths, a configuration is considered in which a cooler is placed in each of the flow paths included in the two oil paths. In this case, two coolers are required, which increases costs. In addition, in order to cool two oil paths, a flow path is provided in the area where the two oil paths join, and a cooler is installed in this flow path. In this case, since it is necessary to provide a flow path in the area where the oil paths exchange, it is necessary to complicate the configuration of the flow path in the oil path, which results in high costs. According to this embodiment, a cooler is provided only in the first oil path 91, and the oil O passing through the first oil path 91 and the second oil path 92 is mixed in the oil reservoir P, so that the second oil path 92 can be indirectly cooled. As a result, the oil O in the first oil path 91 and the second oil path 92 can be cooled by one cooler 97 without complicating the configuration of the flow path in the oil path 90. This effect can be achieved when either the first oil passage 91 or the second oil passage 92 has a cooler 97 that cools the oil O, and the oil O flowing through the first oil passage 91 and the second oil passage 92 join together in the oil reservoir P.

The heat of the oil O is mainly dissipated through the cooler 97. In addition, some of the heat of the oil O is also dissipated through the housing 6 because the oil O comes into contact with the inner surface of the housing 6. As shown in FIG. 1, an uneven heat sink portion 6b may be provided on the outer surface of the housing 6. The heat sink portion 6b promotes cooling of the motor 2 through the housing 6.

(First oil passage) In the first oil passage 91, the oil O is scooped up from the oil reservoir P by the differential gear 5 and guided to the inside of the rotor 20. Inside the rotor 20, the oil O is subjected to centrifugal force accompanying the rotation of the rotor 20. As a result, the oil O is evenly diffused toward the stator 30 that surrounds the rotor 20 from the radial outside, cooling the stator 30.

The first oil passage 91 has a scooping passage 91a, a shaft supply passage (oil flow passage) 91b, an internal shaft passage 91c, and an internal rotor passage 91d. A first reservoir 93 is provided in the first oil passage 91. The first reservoir 93 is provided in the accommodation space 80 (particularly the gear chamber 82).

The scooping path 91a is a path that scoops up oil O from the oil reservoir P by the rotation of the ring gear 51 of the differential device 5 and receives the oil O in the first reservoir 93 (see Figure 3).

As shown in FIG. 3, the first reservoir 93 is located above the motor shaft J2, the intermediate shaft J4, and the differential shaft J5 in the vertical direction. The first reservoir 93 is located between the intermediate shaft J4 and the differential shaft J5 in the vehicle fore-and-aft direction (horizontal direction, X-axis direction). The first reservoir 93 is located between the motor shaft J2 and the differential shaft J5 in the vehicle fore-and-aft direction (horizontal direction, X-axis direction). The first reservoir 93 is disposed on the side of the first gear 41. The first reservoir 93 opens to the upper side.

In this specification, the term "reservoir" refers to a structure that has the function of storing oil when there is no steady flow of liquid in one direction. A "reservoir" differs from a "flow path" in that there is no steady flow of liquid. In this embodiment, a first reservoir 93, a second reservoir 98, and a secondary reservoir 95 are provided in the storage space 80 of the motor unit 1.

In this embodiment, the differential shaft J5, which is the rotation center of the ring gear 51, is disposed on the rear side of the vehicle relative to the reduction gear 4. When the vehicle moves forward, the differential gear 5 rotates upward in the area opposite the reduction gear 4. The oil O scooped up by the ring gear 51 of the differential gear 5 flows around the opposite side of the reduction gear 4 and falls onto the upper side of the first reservoir 93, where it accumulates. That is, the first reservoir 93 receives the oil O scooped up by the ring gear 51. Also, when the liquid level of the oil pool P is high, such as immediately after the motor 2 is driven, the second gear 42 and the third gear 43 come into contact with the oil O in the oil pool P and scoop up the oil O. In such a case, the first reservoir 93 receives the oil O scooped up by the second gear 42 and the third gear 43 in addition to the ring gear 51.

The housing 6 has a gear chamber ceiling portion (ceiling portion) 64 that constitutes the upper wall of the gear chamber 82. The gear chamber ceiling portion 64 is located above the reduction gear 4 and the differential gear 5. Here, a virtual line (a third line segment described later) L3 that virtually connects the motor shaft J2 and the differential shaft J5 when viewed from the axial direction of the motor shaft J2 is defined. The gear chamber ceiling portion 64 is approximately parallel to the virtual line L3. By making the gear chamber ceiling portion 64 approximately parallel to the virtual line L3, a sufficient area is secured through which the oil O that is scooped up by the ring gear 51 and scattered in the direction in which the virtual line L3 extends can pass, and the oil O can be efficiently applied to the first gear 41 that rotates around the motor shaft J. In addition, by making the gear chamber ceiling portion 64 approximately parallel to the virtual line L3, the housing 6 can be prevented from becoming large in the vertical direction. In this case, the gear chamber ceiling 64 and the imaginary line L3 being "substantially parallel" means that the angle between the gear chamber ceiling 64 and the imaginary line L3 is within 10°. If the gear chamber ceiling 64 is curved, the angle between the tangent at every point of the curved line and the imaginary line L3 is within 10°. Also, within the range of 10°, it is preferable that the gear chamber ceiling 64 approaches the imaginary line L3 as it moves toward the differential shaft J5 side or the motor shaft J2 side. This allows the housing 6 to be made smaller.

The gear chamber ceiling 64 is a curved surface that curves slightly in the direction approaching the imaginary line L3 as it moves from the differential shaft J5 side to the motor shaft J2 side. The curved shape of the gear chamber ceiling 64 is substantially the same as the parabola drawn by the oil O scooped up by the ring gear 51, or is a curved surface that moves slightly away from the ring gear 51. A portion of the oil O scooped up by the ring gear 51 reaches the first reservoir 93 directly. Another portion of the oil O scooped up by the ring gear 51 reaches the first reservoir 93 via the gear chamber ceiling 64 of the housing 6. In other words, the gear chamber ceiling 64 plays a role in guiding the oil O to the first reservoir 93.

The gear chamber ceiling 64 has a protrusion 65 that protrudes downward. The protrusion 65 is located above the first reservoir 93. The oil O running down the gear chamber ceiling 64 becomes large droplets at the lower end of the protrusion 65, drops downward and accumulates in the first reservoir 93. That is, the protrusion 65 guides the oil O running down the gear chamber ceiling 64 to the first reservoir 93. In this embodiment, the motor accommodating portion 61 and the gear accommodating portion 62 are fixed to each other by a bolt 67. The protrusion 65 is provided by utilizing a thick portion of the gear chamber ceiling 64 around a screw hole into which the bolt 67 is inserted. Note that in FIG. 3, other bolts that fix the motor accommodating portion 61 and the gear accommodating portion 62 and other thick portions around the screw hole are omitted from the illustration.

The gear chamber ceiling 64 has a plate-shaped eaves portion 66 extending along the axial direction. The eaves portion 66 protrudes downward. The lower end of the eaves portion 66 is located above the first reservoir 93. Some of the oil O scooped up and scattered by the ring gear 51 hits the eaves portion 66 and runs down the surface of the eaves portion 66. Similarly, the oil O scooped up and scattered by the second gear 42 and the third gear is received by the eaves portion 66 and runs down the surface of the eaves portion 66. The oil O becomes large droplets at the lower end of the eaves portion 66, falls downward, and accumulates in the first reservoir 93. That is, the eaves portion 66 guides the scooped up oil O to the first reservoir 93. The eaves portion 66 inclines from the differential shaft J5 side toward the motor shaft J2 side as it moves from the top to the bottom. Because the ring gear 51 has a larger diameter than the second gear 42 and the third gear 43, the angle at which the oil O scatters is close to horizontal. By positioning the eaves portion 66 at an angle in the above-mentioned direction, the oil O that scatters from the ring gear 51 can be smoothly attached to the surface of the eaves portion 66 and allowed to fall to the bottom.

The first reservoir 93 is located directly above the ring gear 51, the second gear 42, and the third gear 43. The opening of the first reservoir 93 overlaps with the ring gear 51, the second gear 42, and the third gear 43 when viewed vertically. Most of the oil scooped up by the gears is scattered directly above the gears that scoop it up. By positioning the first reservoir 93 directly above the ring gear 51, the second gear 42, and the third gear 43, the oil O scooped up by each gear can be efficiently received.

The first reservoir 93 has a bottom 93a, a first side wall 93b, and a second side wall 93c. The bottom 93a, the first side wall 93b, and the second side wall 93c extend along the axial direction between the wall surfaces of the gear accommodating section 62 and the protruding plate section 61d of the motor accommodating section. The first side wall 93b and the second side wall 93c extend upward from the bottom 93a. The first side wall 93b constitutes the wall surface of the first reservoir 93 on the differential device 5 side. The second side wall 93c constitutes the wall surface of the first reservoir 93 on the reduction gear 4 side. That is, the first side wall 93b extends upward from the end of the bottom 93a on the differential shaft J5 side, and the second side wall 93c extends upward from the end of the bottom 93a on the motor shaft J2 side. The first reservoir 93 temporarily stores oil O in an area surrounded by the bottom 93a, the first side wall 93b, the second side wall 93c, and the wall surfaces of the gear housing 62 and the protruding plate 61d of the motor housing.

The height of the upper end of the first side wall portion 93b is located lower than the upper end of the second side wall portion 93c. The oil O is scooped up by the differential device 5 and splashes toward the first reservoir 93 from the opposite side of the reduction gear 4. By lowering the height of the upper end of the first side wall portion 93b, the oil O scooped up by the differential device 5 can be efficiently stored in the first reservoir 93. In addition, the oil O that is scooped up by the ring gear 51 and splashes and exceeds the first side wall portion 93b can be guided to the first reservoir 93 by hitting the second side wall portion 93c.

The second side wall portion 93c extends diagonally upward along the circumferential direction of the first gear 41. That is, the second side wall portion 93c inclines toward the motor shaft J2 as it moves upward. This allows the second side wall portion 93c to receive a wide range of oil O scooped up by the differential device 5. In addition, the second side wall portion 93c can receive a wide range of oil O droplets running down the ceiling of the storage space 80.

At the boundary between the bottom 93a and the second sidewall 93c, a shaft supply passage 94 opens toward the inside of the first reservoir 93. The bottom 93a is slightly inclined downward as it approaches the motor shaft J2 in a plan view. In other words, the bottom 93a is slightly inclined so that its lower end is on the second sidewall 93c side. Therefore, by providing an opening of the shaft supply passage 94 between the bottom 93a and the second sidewall 93c, the oil O in the first reservoir 93 can be efficiently supplied to the shaft supply passage 94.

The shaft supply passage 91b guides the oil O from the first reservoir 93 to the motor 2. The shaft supply passage 91b is composed of a shaft supply flow passage 94. The shaft supply flow passage 94 extends from the first reservoir 93 toward the end of the shaft 21. The shaft supply flow passage 94 extends in a straight line. The shaft supply flow passage 94 inclines downward as it extends from the first reservoir 93 toward the end of the shaft 21. The shaft supply flow passage 94 is formed by machining a hole that penetrates the inside and outside of the housing space 80 in the gear housing portion 62. The outer opening of the machined hole is closed by a cap (not shown). The shaft supply flow passage 94 guides the oil O that has accumulated in the first reservoir 93 from the end of the shaft 21 to the hollow portion 22.

As shown in FIG. 1, the shaft internal path 91c is a path through which oil O passes through the hollow portion 22 of the shaft 21. The rotor internal path 91d is a path through which oil O passes from the communication hole 23 of the shaft 21 through the inside of the end plate 26 located on the axial end face 24a of the rotor core 24 and splashes onto the stator 30 (see FIG. 5). That is, the first oil path 91 has a path that passes from the inside of the shaft 21 through the rotor core 24.

In the shaft passage 91c, centrifugal force is applied to the oil O inside the rotor 20 as the rotor 20 rotates. As a result, the oil O is continuously scattered radially outward from the end plate 26. As the oil O scatters, negative pressure is created in the passage inside the rotor 20, and the oil O that has accumulated in the first reservoir 93 is sucked into the rotor 20, filling the passage inside the rotor 20 with oil O. The movement of the oil O into the rotor 20 is also promoted by capillary force in the first oil passage 91. The oil O that reaches the stator 30 absorbs heat from the stator 30.

(Second oil passage) As shown in FIG. 1, in the second oil passage 92, the oil O is pulled up from the oil reservoir P to the upper side of the motor 2 and supplied to the motor 2. The oil O supplied to the motor 2 absorbs heat from the stator 30 while flowing along the outer peripheral surface of the stator 30, thereby cooling the motor 2. The oil O that flows along the outer peripheral surface of the stator 30 drips downward and accumulates in the lower region of the motor chamber 81. The oil O in the second oil passage 92 merges with the oil O in the first oil passage 91 in the lower region of the motor chamber 81. The oil O that has accumulated in the lower region of the motor chamber 81 moves to the lower region of the gear chamber 82 (i.e., the oil reservoir P) through the partition opening 68.

Figure 10 is a cross-sectional view of the motor unit 1. Note that the cut surfaces in Figure 10 are shifted in the axial direction in each region. The second oil passage 92 has a first flow path 92a, a second flow path 92b, and a third flow path 92c. A pump 96, a cooler 97, and a second reservoir 98 are provided in the second oil passage 92. In the second oil passage 92, oil O passes through each part in the order of the first flow path 92a, the pump 96, the second flow path 92b, the cooler 97, the third flow path 92c, and the second reservoir 98, and is supplied to the motor 2.

The pump 96 is an electric pump driven by electricity. The pump 96 is attached to a pump mounting recess 6c provided on the outer surface of the housing 6. The pump 96 has an intake port 96a and an exhaust port 96b. The intake port 96a and the exhaust port 96b are connected via an internal flow path of the pump 96. The intake port 96a is connected to the first flow path 92a. The exhaust port 96b is connected to the second flow path 92b. The exhaust port 96b is located above the intake port 96a. The pump 96 sucks up oil O from the oil reservoir P through the first flow path 92a and supplies it to the motor 2 through the second flow path 92b, the cooler 97, the third flow path 92c, and the second reservoir 98.

The amount of oil O supplied to the motor 2 by the pump 96 is appropriately controlled according to the driving state of the motor 2. Therefore, when the temperature of the motor 2 rises, such as when long-term driving or high output is required, the driving output of the pump 96 is increased and the amount of oil O supplied to the motor 2 is increased.

The cooler 97 has an inlet 97a and an outlet 97b. The inlet 97a and the outlet 97b are connected via an internal flow path of the cooler 97. The inlet 97a is connected to the second flow path 92b. The outlet 97b is connected to the third flow path 92c. The inlet 97a is located closer to the pump 96 (i.e., lower) than the outlet 97b. Inside the cooler 97, a cooling water pipe (not shown) through which the cooling water supplied from the radiator passes is provided. The oil O passing inside the cooler 97 is cooled by heat exchange with the cooling water.

The pump 96 and the cooler 97 are fixed to the outer peripheral surface of the motor accommodating portion 61 of the housing 6. When viewed in the axial direction of the motor shaft J2, the pump 96 and the cooler 97 are positioned on the horizontal opposite side of the motor shaft J2 to the differential device 5. The pump 96 and the cooler 97 are also aligned in the vertical direction. The cooler 97 is positioned above the pump 96. When viewed vertically, the cooler 97 overlaps with the pump 96.

In this embodiment, the pump 96 and the cooler 97 are located on the opposite side of the motor shaft J2 from the differential device 5, making it possible to effectively utilize the space around the motor 2. This makes it possible to reduce the horizontal dimensions of the entire motor unit 1, thereby enabling the motor unit 1 to be made more compact.

According to this embodiment, the pump 96 and the cooler 97 are fixed to the outer peripheral surface of the housing 6. This contributes to a more compact motor unit 1 than when the pump 96 and the cooler 97 are provided outside the housing 6. In addition, by fixing the pump 96 and the cooler 97 to the outer peripheral surface of the housing 6, the first flow path 92a, the second flow path 92b, and the third flow path 92c that pass through the inside of the wall portion 6a of the housing 6 can form flow paths that connect the storage space 80 with the pump 96 and the cooler 97.

In this embodiment, the cooler 97 is fixed to the outer peripheral surface of the housing 6, so the distance between the storage space 80 and the cooler 97 can be reduced. This allows the third flow path 97c connecting the cooler 97 and the storage space 80 to be shortened, and cooled oil O can be supplied to the storage space 80 at a low temperature.

The first flow path 92a, the second flow path 92b, and the third flow path 92c pass through the inside of the wall portion 6a of the housing 6 that surrounds the storage space 80. The first flow path 92a can be formed as a hole formed in the wall portion 6a, and the first flow path 92a, the second flow path 92b, and the third flow path 92c can be formed. Therefore, there is no need to prepare a separate pipe material, which contributes to reducing the number of parts. The first flow path 92a passes through the inside of a portion of the wall portion 6a that is located below the motor 2. The second flow path 92b passes through the inside of a portion of the wall portion 6a that is located horizontally to the side of the motor 2. The third flow path 92c passes through the inside of a portion of the wall portion 6a that is located above the motor 2.

The first flow passage 92a connects the oil reservoir P and the pump 96. The first flow passage 92a has a first end 92aa and a second end 92ab. The first end 92aa is located upstream of the second oil passage 92 compared to the second end 92ab. The first end 92aa opens into the accommodation space 80 below the differential device 5. When viewed vertically, the first end 92aa overlaps with the motor 2. The second end 92ab opens into the pump mounting recess 6c and connects to the suction port 96a of the pump 96.

As described above, the differential device 5 and the pump 96 are located on opposite sides in the horizontal direction with the motor shaft J2 in between. The first flow passage 92a extends across the motor 2 on opposite sides in the horizontal direction. The first flow passage 92a also passes below the motor 2.

In this embodiment, the first flow path 92a passes under the motor 2, so the area under the motor 2 can be effectively used to reduce the dimensions of the motor unit 1. This allows the motor unit 1 to be made more compact.

At least a portion of the first flow passage 92a overlaps with the second gear 42 and the ring gear 51 when viewed from the axial direction. This allows the dimensions of the motor unit 1 to be reduced when viewed from the axial direction, making it possible to miniaturize the motor unit 1. In this embodiment, the second gear 42 and the ring gear 51 of the multiple gears (first gear 41, second gear 42, third gear 43, and ring gear 51) connected between the motor 2 and the differential device 5 overlap with the first flow passage 92a when viewed from the axial direction. However, the above-mentioned effect can be achieved if at least one of the multiple gears connected between the motor 2 and the differential device 5 overlaps with the first flow passage 92a when viewed from the axial direction.

The first flow passage 92a extends from the lower side of the differential device 5 to the intake port 96a of the pump 96. The first flow passage 92a is inclined upward from the first end 92aa to the second end 92ab, and then extends linearly. The intake port 96a of the pump 96 is located above the lower end of the differential device 5 and below the motor shaft J2.

The pump 96 is preferably positioned away from the road surface to prevent collisions with flying stones from the road surface when the motor unit 1 is mounted on the vehicle. On the other hand, by positioning the intake port 96a of the pump 96 below the oil level of the oil reservoir P, it is possible to suppress the entrainment of air.

The intake port 96a in this embodiment is located below the motor shaft J2. This makes it easy to position the intake port 96a below the oil level of the oil reservoir P. The intake port 96a in this embodiment is also located above the lower end of the differential device 5. This makes it possible to realize a structure that separates the pump 96 from the road surface. Also, by positioning the intake port 96a below the motor shaft J2, it becomes easier to configure the first flow path 92a in a straight line. Therefore, when a structure is adopted in which the first flow path 92a passes through the inside of the wall portion 6a of the housing 6, the ease of machining the first flow path 92a can be improved.

In this embodiment, the suction port 96a is located below the liquid level of the oil reservoir P in the storage space 80. The height of the liquid level of the oil reservoir P varies as oil O is supplied from the oil reservoir P to the first oil passage 91 and the second oil passage 92. The suction port 96a is located below the liquid level even when the liquid level of the oil reservoir P is at its lowest. In FIG. 1, the suction port 96a is depicted as being located above the liquid level of the oil reservoir P. However, FIG. 1 is merely a schematic diagram, and the actual suction port 96a is located below the liquid level of the oil reservoir P.

The second flow path 92b connects the pump 96 and the cooler 97. The second flow path 92b has a first end 92ba and a second end 92bb. The first end 92ba opens into the pump mounting recess 6c and connects to the discharge port 96b of the pump 96. The first end 92ba is located upstream of the second oil passage 92 compared to the second end 92bb. The second end 92bb connects to the inlet 97a of the cooler 97. The second end 92bb is located above the first end 92ba.

The second flow path 92b has a first path 92bd and a second path 92be. The first path 92bd extends upward from the pump mounting recess 6c. The second path 92be extends horizontally from the upper end of the first path 92bd. The first path 92bd and the second path 92be are formed by machining holes in the wall portion 6a of the housing 6 that extend in different directions and intersect with each other.

The third flow passage 92c connects the cooler 97 and the storage space 80. The third flow passage 92c extends linearly along the horizontal direction. The third flow passage 92c has a first end 92ca and a second end 92cb. The first end 92ca is located upstream of the second oil passage 92 compared to the second end 92cb. The first end 92ca is connected to the outlet 97b of the cooler 97. The second end 92cb opens into the storage space 80 above the motor 2. That is, the third flow passage 92c opens into the storage space 80 above the motor 2. The second end 92cb of the third flow passage 92c functions as a supply section 99 that supplies oil O to a second reservoir 98 located in the storage space 80. That is, the second oil passage 92 supplies oil O to the second reservoir 98 at the supply section 99.

The outlet 97b of the cooler 97 overlaps with the motor 2 in the axial direction of the motor shaft J2. That is, the outlet 97b of the cooler 97 is arranged so as to overlap with the motor 2 when viewed from the radial direction. In other words, the outlet 97b of the cooler 97 is located between both ends of the stator 30 in the axial direction. Therefore, the third flow path 92c connecting the outlet 97b of the cooler 97 with the storage space 80 can be shortened, and the cooled oil O can be supplied to the storage space 80 at a low temperature. In addition, by arranging the third flow path 97c so as to overlap with the motor 2 in the radial direction, the axial dimension of the motor unit 1 can be reduced, and the motor unit 1 can be made more compact.

(Second reservoir) Figure 11 is a perspective view of the motor unit 1. Figure 12 is a plan view of the second reservoir 98. Note that in Figure 11, the motor accommodating section 61 and the closing section 63 of the housing 6 are omitted.

As shown in FIG. 11, the second reservoir (main reservoir) 98 is located in the motor chamber 81 of the accommodation space 80. The second reservoir 98 is located above the motor. The second reservoir 98 has a bottom (first bottom 98c and second bottom 98g) and sidewalls (first sidewall 98d, second sidewall 98e, third sidewall 98f, fourth sidewall 98h, fifth sidewall 98i, sixth sidewall 98j and seventh sidewall 98n) extending upward from the bottom. The second reservoir 98 stores oil O supplied to the motor chamber 81 via the supply portion 99 of the third flow path 92c in a space surrounded by the bottom and the sidewalls. The second reservoir 98 has multiple outlets (a first outlet 98r, a second outlet 98o, a third outlet 98x, a fourth outlet 98t, a fifth outlet 98u, and a sixth outlet 98v). Each outlet supplies the oil O stored in the second reservoir 98 to the motor 2. That is, the second reservoir 98 supplies the stored oil O to each part of the motor 2 from above via the outlets.

According to this embodiment, the second reservoir 98 is located above the motor 2 and supplies the stored oil O to the upper side of the motor 2 from multiple outlets. The oil O flows from the top to the bottom along the outer circumferential surface of the motor 2, removing heat from the motor 2 and allowing the entire motor 2 to be cooled.

As shown in FIG. 12, the second reservoir 98 has a first end 98p located on the gear chamber 82 side in the axial direction, and a second end 98q located on the opposite side of the first end 98p in the axial direction. The second reservoir 98 also has a trough-shaped first storage portion 98A extending along the axial direction, and a second storage portion 98B located on the second end 98q side of the first storage portion 98A.

The first storage section 98A has a first bottom 98c, a first side wall section 98d, a second side wall section 98e, and a third side wall section 98f. The first storage section 98A is also provided with a first outlet 98r, a second outlet 98o, and a third outlet 98x.

The first bottom 98c is rectangular with the axial direction as the longitudinal direction. Both axial ends of the first bottom 98c are located above the coil ends 31a provided at both ends of the stator 30. A first outlet 98r is provided in the first bottom 98c. The first outlet 98r is located in the area on the first end 98p side of the first bottom 98c.

The first side wall portion 98d and the second side wall portion 98e extend along the axial direction. The first and second side wall portions 98e face each other in the circumferential direction of the motor shaft J2. The first side wall portion 98d is provided with an inlet 98s. The inlet 98s is a U-shaped notch that opens upward. A supply portion 99 is connected to the inlet 98s. The inlet 98s is located in the middle of the first side wall portion 98d in the axial direction. This allows the inlet 98s to flow oil O to the first end portion 98p and the second end portion 98q of the second reservoir 98.

The second side wall portion 98e is provided with a convex portion 98w that protrudes toward the first side wall portion 98d. The convex portion 98w is located in front of the inlet 98s. The convex portion 98w has an inclined surface that reduces the protruding height from the center toward the first end portion 98p and the second end portion 98q. The convex portion 98w smoothly divides the oil O that flows from the inlet 98s to the second reservoir 98 between the first end portion 98p and the second end portion 98q.

A second outlet 98o is provided in the second side wall portion 98e. The second outlet 98o is located in the area on the first end portion 98p side of the second side wall portion 98e. The second outlet 98o is located near the first outlet 98r.

As shown in FIG. 11, the third side wall portion 98f is located on the first end 98p side of the second reservoir 98. The third side wall portion 98f is located above one coil end 31a of the stator 30. The height of the upper end of the third side wall portion 98f is lower than the height of the upper ends of the first side wall portion 98d and the second side wall portion 98e. The height of the upper end of the third side wall portion 98f is approximately equal to the height of the opening lower end of the second outlet 98o. The space above the second side wall portion 98e functions as a third outlet 98x from which the oil O flows out when the level of the oil O stored in the second reservoir 98 becomes high.

The second storage portion 98B extends along the circumferential direction of the stator 30. The second storage portion 98B has a second bottom portion 98g, a fourth side wall portion 98h, a fifth side wall portion 98i, a sixth side wall portion 98j, a seventh side wall portion 98n, and a step portion 98k. The second storage portion 98B is also provided with a fourth outlet 98t, a fifth outlet 98u, a sixth outlet 98v, and an overflow portion 98y.

The second bottom 98g is located on the second end 98q side of the first bottom 98c. The second bottom 98g is located below the first bottom 98c. A step portion 98k is provided at the boundary between the first bottom 98c and the second bottom 98g. The second storage portion 98B is located below the first storage portion 98A. Oil O that flows to the second end 98q side in the first storage portion 98A accumulates in the second storage portion 98B.

The second bottom 98g is located above one coil end 31a of the stator 30. The second bottom 98g curves along the outer peripheral surface of the motor 2. This allows the volume of oil O stored in the second reservoir 98 to be increased without increasing the dimensions of the motor unit 1. The second bottom 98g slopes downward from the portion that overlaps with the motor shaft J2 when viewed from the top-bottom direction toward both sides in the circumferential direction. The second storage section 98B is connected to the first storage section 98A on one side across the motor shaft J2 when viewed from the top-bottom direction.

As shown in FIG. 12, the second storage section 98B is divided into a first region 98gA, which is an area on one side of the motor shaft J2 and connected to the first storage section 98A when viewed from the top-bottom direction, and a second region 98gB, which is an area on the other side of the motor shaft J2. The second bottom 98g is highest at the boundary between the first region 98gA and the second region 98gB. The oil O that flows from the first storage section 98A to the second storage section 98B first accumulates in the first region 98gA, and when the liquid level accumulated in the first region 98gA reaches the height of the boundary line, the oil O flows into the second region 98gB. In this way, the boundary line functions as a weir 98gC provided on the second bottom 98g. That is, the second bottom 98g is provided with a weir 98gC that protrudes upward and divides the second storage section 98B of the second reservoir 98 into a first region 98gA and a second region 98gB. The oil O flows into one region (the first region 98gA) and when the liquid level exceeds the weir 98gC, the oil O flows into the other region (the second region 98gB).

As described later, the sixth side wall portion 98j extending in the circumferential direction is provided with a fourth outlet 98t, a fifth outlet 98u, and a sixth outlet 98v aligned in the circumferential direction. The fifth side wall portion 98i is also provided with an overflow portion 98y. The fourth outlet 98t and the fifth outlet 98u open to the first region 98gA, and the sixth outlet 98v and the overflow portion 98y open to the second region 98gB. That is, the second reservoir 98 is provided with outlets in each of the multiple regions (the first region 98gA and the second region 98gB) partitioned by the weir 98gC. Therefore, the oil O flows out only from the fourth outlet 98t and the fifth outlet 98u until the liquid level in the first region 98gA exceeds the weir 98gC. In addition, after the liquid level in the first region 98gA exceeds the weir 98gC, the oil O flows out from the fourth outlet 98t, the fifth outlet 98u, the sixth outlet 98v, and the overflow portion 98y. Therefore, according to this embodiment, the second reservoir 98 can increase the number of outlets for oil O when the amount of oil O stored therein increases. In particular, when the load on the motor 2 increases and the motor 2 becomes hot, the amount of oil O supplied to the second reservoir 98 by the pump 96 increases. Therefore, according to this embodiment, when the motor 2 becomes hot, the supply points of oil O to the motor 2 can be increased to expand the cooling range and increase the amount of oil O supplied to the motor 2.

The fourth side wall portion 98h and the fifth side wall portion 98i are located at both circumferential ends of the second storage portion 98B. The fourth side wall portion 98h and the fifth side wall portion 98i face each other in the circumferential direction. The fourth side wall portion 98h and the fifth side wall portion 98i extend along the axial direction. The fourth side wall portion 98h extends toward the second end portion 98q, continuing from the first side wall portion 98d.

The fifth side wall portion 98i is provided with an overflow portion 98y. The overflow portion 98y is a locally low portion provided at the upper end of the fifth side wall portion 98i. The overflow portion 98y is located above the lower ends of the openings of the fourth outlet 98t, the fifth outlet 98u, and the sixth outlet 98v of the second storage portion 98B. Therefore, the oil O overflows from the overflow portion 98y after the liquid level in the second storage portion 98B becomes higher than the fourth outlet 98t, the fifth outlet 98u, and the sixth outlet 98v. A secondary reservoir 95, which will be described later, is provided below the overflow portion. The oil O overflowing from the overflow portion 98y is stored in the secondary reservoir 95. In this specification, "overflow" means that the oil flows out of the reservoir when the liquid in the reservoir reaches a certain liquid level. Therefore, if liquid flows out from the bottom of the reservoir, it does not qualify as "overflowing."

The sixth side wall portion 98j is located on the second end 98q side of the second reservoir 98. The sixth side wall portion 96j extends along the circumferential direction. The sixth side wall portion 98j is located on the upper side of one coil end 31a of the stator 30. The sixth side wall portion 98j is provided with a fourth outlet 98t, a fifth outlet 98u, and a sixth outlet 98v. The fourth outlet 98t, the fifth outlet 98u, and the sixth outlet 98v are holes provided in the sixth side wall portion 98j and penetrate the inside and outside of the second reservoir 98. The fourth outlet 98t, the fifth outlet 98u, and the sixth outlet 98v are aligned along the circumferential direction. As shown in FIG. 11, the fourth outlet 98t, the fifth outlet 98u, and the sixth outlet 98v have different heights. Therefore, according to this embodiment, the number of outlets through which the oil O flows out can be increased depending on the level of the oil O in the second reservoir 98. This increases the number of supply points of the oil O to the motor 2, widening the cooling range, and increasing the amount of oil O supplied to the motor 2. This effect can be achieved if at least two of the multiple outlets provided in the second reservoir 98 are different in height.

The seventh side wall portion 98n extends in the circumferential direction. The seventh side wall portion 98n faces the sixth side wall portion 98j in the axial direction. The seventh side wall portion 98n is continuous with the step portion 98k in the circumferential direction. The seventh side wall portion 97n is provided with an accommodating portion 98na that accommodates the fixing screw of the stator core 32.

According to this embodiment, the second oil passage 92 supplies the oil O stored in the second reservoir 98 to the motor 2 from multiple outlets. Each outlet supplies the oil O to the motor 2 at a constant flow rate, so the efficiency of cooling the motor 2 by the oil O can be improved.

According to this embodiment, the second reservoir 98 has multiple outlets (a first outlet 98r, a second outlet 98o, a third outlet 98x, a fourth outlet 98t, a fifth outlet 98u, and a sixth outlet 98v). Therefore, the second reservoir 98 can supply oil O to the motor 2 from multiple locations at the same time, and each part of the motor 2 can be cooled simultaneously.

According to this embodiment, the second reservoir 98 extends along the axial direction. The second reservoir 98 is provided with an outlet at each of both axial ends. The outlets at both axial ends of the second reservoir 98 are located above the coil end 31a. This allows the coil 31 to be directly cooled by pouring oil O onto the coil ends 31a located at both axial ends of the stator 30. More specifically, the oil O poured onto the coil 31 seeps in through the gaps between the conductors that make up the coil 31. The oil O that has soaked into the coil 31 absorbs heat from the coil while permeating the entire coil 31 due to the capillary force acting on the conductor tube and gravity. Furthermore, the oil O accumulates at the bottom of the inner circumferential surface of the stator core 32 and drips from both axial ends of the coil 31. The effect of directly cooling the oil O by supplying the oil O directly to the coil end 31a can be achieved by positioning at least two of the multiple outlets at both axial ends of the second reservoir 98.

According to this embodiment, the supply unit 99 that supplies oil O to the second reservoir 98 is located between the outlets located at both ends of the second reservoir 98 in the axial direction. Therefore, the oil O supplied from the supply unit 99 can flow out from the outlets located at both ends.

(Modified example of second reservoir) Figure 13 is a perspective view of a modified second reservoir 198 that can be used in this embodiment. Note that components that are the same as those in the above-described embodiment are described using the same reference numerals. The modified second reservoir 198 is a shallow rectangular box that is open at the top. The second reservoir 198 has a central oil storage section 198a and four oil supply sections 198b located around the central oil storage section 198a. The central oil storage section 198a and the four oil supply sections 198b are partitioned from each other.

The central oil reservoir 198a stores the oil O flowing in from the supply section 99. The central oil reservoir 198a is separated from the oil supply section 198b by a circular bottom surface 198ab and a cylindrical wall 198aa extending upward from the bottom surface 198ab.

The four oil supply units 198b are arranged around the central oil storage unit 198a. The oil supply units 198b have a roughly rectangular shape. An outlet 198c that connects the inside and outside of the oil supply unit 198b is provided near the corner between two outer walls 198ba that extend in different directions of the oil supply unit 198b. One of the two outlets 198c opens in the axial direction of the motor 2, and the other opens in the circumferential direction. As each of the four oil supply units 198b has two outlets 198c, the second reservoir 198 has a total of eight outlets 198c.

The second reservoir 198 is installed above the stator 30 so that its bottom surface is horizontal. When the oil O supplied from the supply section 99 fills the central oil storage section 198a, it overflows from the cylindrical wall 198aa and flows into the four oil supply sections 198b. Because the second reservoir 198 is installed horizontally and the cylindrical wall 198aa is the same height all around, the oil O flows evenly into the four oil supply sections 198b. The oil O accumulates in the four oil supply sections 198b and flows out from the outlet 198c to the outside.

The axial length of the second reservoir 198 is longer than the axial length of the stator core 32. Oil O is supplied to the motor 2 from one oil supply section 198b via two outlets 198c facing in the axial and circumferential directions. According to this modified example, the second reservoir 198 can supply oil O to the motor 2 from multiple outlets in multiple directions.

(Secondary reservoir) Figure 14 is a cross-sectional view of the motor unit 1 showing an outline of the secondary reservoir 95. In Figure 14, the protrusion 63d provided on the closing portion 63 of the housing 6 is shown by a virtual line. Also in Figure 14, the oil O stored in the secondary reservoir 95 is highlighted by a dot pattern. The secondary reservoir 95 receives the oil O that overflows from the second reservoir 98 in the second oil passage 92. That is, the secondary reservoir 95 that stores the oil O is provided in the path of the second oil passage 92. The second reservoir 98 functions as a main reservoir with respect to the secondary reservoir 95. The second reservoir 98 is located upstream of the second oil passage 92 with respect to the secondary reservoir 95.

The secondary reservoir 95 is located directly below the overflow portion 98y. In other words, the secondary reservoir 95 and the overflow portion 98y overlap when viewed vertically. This allows the secondary reservoir 95 to receive the oil O that overflows from the second reservoir 98.

The secondary reservoir 95 has a first portion 95A located on one circumferential side of the second reservoir 98, and a second portion 95B located on the other circumferential side. The first portion 95A and the second portion 95B are connected to each other. The secondary reservoir 95 has a total of four outlets 61k, two each in the first portion 95A and the second portion 95B. The four outlets 61k are aligned along the circumferential direction of the motor 2. The multiple outlets 61k are also at different heights.

The auxiliary reservoir 95 is composed of the inner surface 61g of the motor accommodating section 61 and the inner wall surface of the protruding section 63d of the blocking section 63. The inner surface 61g of the motor accommodating section 61 has an inner circumferential surface 61i facing radially inward and an opposing surface 61h facing the blocking section 63 in the axial direction. The opposing surface 61h contacts the axial surface of the protruding section 63d. Oil O does not flow out from the contact area between the protruding section 63d and the opposing surface 61h. According to this embodiment, since the auxiliary reservoir 95 is configured as a gap between other components, there is no need to use other components, and an increase in the number of parts can be suppressed.

The opposing surface 61h is provided with recesses 61j arranged along the circumferential direction and recessed in the axial direction. The recesses 61j are recessed in a direction that increases the gap between the inner surface 61g of the motor housing portion 61 and the inner wall surface of the protruding portion 63d. The oil O flows out downward from the recesses 61j. That is, the recesses 61j form an outlet 61k. The outlet 61k is located above the coil end 31a of the stator 30. Therefore, the oil O flowing out from the outlet 61k cools the coil 31 of the coil end 31a. In this embodiment, the case where the recesses 61j are provided on the inner surface 61g at the contact portion between the inner surface 61g of the motor housing portion 61 and the inner wall surface of the protruding portion 63d is exemplified. However, a recess may be provided on the inner wall surface of the protruding portion 63d.

According to this embodiment, by providing the secondary reservoir 95 in addition to the second reservoir 98, the oil O can flow out not only from the outlet of the second reservoir 98 but also from the outlet 61k of the secondary reservoir 95, thereby cooling a wide range of the motor 2. Furthermore, the multiple outlets 61k of the secondary reservoir 95 are arranged side by side in the circumferential direction. This allows the coil end 31a of the stator 30 to be cooled over a wide range. Furthermore, since the multiple outlets 61k are at different heights, the timing of outflow can be varied depending on the level of the oil O stored in the secondary reservoir 95.

According to this embodiment, oil O that overflows from the second reservoir 98 is stored in the secondary reservoir 95. The pump 96 increases the amount of oil O supplied to the second reservoir 98 when the motor 2 is under high load and the temperature rises. Therefore, when the motor 2 is under high load, oil O overflows from the second reservoir 98 and can be supplied to the motor 2 at the outlet 61k of the secondary reservoir 95 as well. According to this embodiment, when the motor 2 is under high load, a wide range of the motor 2 can be cooled by oil O. In other words, by providing the secondary reservoir 95, the supply range of oil O supplied to the motor 2 can be automatically expanded when the operation of the motor 2 changes from a steady state to a high load state.

In addition, the lower end of the secondary reservoir 95 in this embodiment is located above the motor shaft J2. Therefore, the outlet 61k of the secondary reservoir 95 is located above the motor shaft J2. The motor 2 is generally cylindrical. By locating the lower end of the secondary reservoir 95 above the motor shaft J2, the oil O flowing out from the outlet 61k can be made to flow along the surface of the motor 2 to cool the motor 2. In addition, the motor 2 is widest in a horizontal cross section passing through the motor shaft J2. By locating the lower end of the secondary reservoir 95 above the motor shaft J2, the oil O flowing along the surface of the motor 2 passes through the area where the horizontal dimension of the motor is widest. This allows the motor 2 to be cooled efficiently.

(Common portion of the first oil passage and the second oil passage) As shown in FIG. 1, when the motor 2 is in the driving state, the oil O is supplied to the motor 2 via the first oil passage 91 and the second oil passage 92. The oil O supplied to the motor 2 drips downward while cooling the motor 2, and accumulates in the lower region of the motor chamber 81. The oil O that has accumulated in the lower region of the motor chamber 81 moves to the gear chamber 82 via the partition opening 68 provided in the partition 61c.

Figure 15 is a front view of the partition 61c of the housing 6 as seen from the motor chamber 81 side. The partition opening 68 is located below the insertion hole 61f through which the shaft 21 passes. The partition opening 68 has a first opening 68a and a second opening 68b located above the first opening 68a. The first opening 68a and the second opening 68b each connect the motor chamber 81 and the gear chamber 82.

As shown in FIG. 19, the lower end of the partition opening 68 (i.e., the lower end of the first opening 68a) is located above the lower limit height Lmin of the oil O liquid level in the gear chamber 82 when the motor 2 is stationary. Therefore, the partition opening 68 can move as much oil O as possible to the oil reservoir P when the motor 2 is in a stationary state where the motor 2 is not driven.

As shown in FIG. 15, the first opening 68a is circular in plan view. The lower end of the first opening 68a is located below the lower end of the stator 30. The first opening 68a is located near the bottom 81a of the motor chamber 81. Therefore, the first opening 68a moves the oil O to the gear chamber 82 until the oil O that accumulates in the area below the motor chamber 81 is almost depleted.

The first opening 68a overlaps with the motor shaft J2 when viewed from the top-bottom direction. The first opening 68a is also located in a recess 61q provided on the inner circumferential surface of the peripheral wall portion 61a. Here, the peripheral wall portion 61a and the recess 61q will be described. The motor accommodating portion 61 of the housing 6 has a peripheral wall portion 61a having a cylindrical shape that follows the outer circumferential surface of the stator 30. The inner circumferential surface of the peripheral wall portion 61a is provided with a recess 61q that is recessed radially outward. The recess 61q extends along the axial direction. The recess 61q is located directly below the motor shaft J2. In other words, the recess 61q overlaps with the motor shaft J2 when viewed from the top-bottom direction. Because the peripheral wall portion 61a has a cylindrical shape, the oil O in the motor chamber 81 flows along the inner circumferential surface of the peripheral wall portion 61a and collects inside the recess 61q. Because the first opening 68a is located in the recess 61q, the oil O in the motor chamber 81 that has collected inside the recess 61q can be efficiently moved to the gear chamber 82.

The second opening 68b is located above the first opening 68a. The second opening 68b is a rectangle with the horizontal direction as the longitudinal direction in a plan view. The second opening 68b has a larger opening area than the first opening 68a. The second opening 68b also has a larger width in the horizontal direction compared to the first opening 68a. The second opening 68b has a lower end 68c that extends along the horizontal direction.

When the motor 2 is driven, the amount of oil O supplied per unit time from the oil passage 90 (i.e., the first oil passage 91 and the second oil passage 92) to the motor 2 increases. This causes the level of the oil O pooled in the lower region of the motor chamber 81 to rise. In the partition opening 68, the region located below the liquid level of the oil O pooled in the lower region of the motor chamber 81 is called the first region S, and the region located above the liquid level is called the second region R. The partition opening 68 moves the oil O in the first region S to the gear chamber 82. When the liquid level of the oil O pooled in the lower region of the gear chamber 82 rises, the area of the first region S increases and the area of the second region R decreases. When the area of the first region S increases, the amount of oil O moving from the motor chamber 81 to the gear chamber 82 through the partition opening 68 increases.

The partition opening 68 in this embodiment is arranged so that when the level of the oil O in the motor chamber 81 becomes high, the amount of oil O moving from the motor chamber 81 to the gear chamber 82 through the partition opening 68 increases. This prevents the level of the oil O in the motor chamber 81 from becoming too high. That is, the rotor 20 in the motor chamber 81 can be prevented from being immersed in the oil O or from excessively stirring up the oil O. This prevents the rotation efficiency of the motor 2 from decreasing due to the flow resistance of the oil O. In addition, according to this embodiment, the oil O in the motor chamber 81 can be moved to the gear chamber 82 side according to the level of the oil O in the motor chamber 81, thereby making effective use of the oil O in the motor unit 1. This not only reduces the amount of oil O used and reduces the weight of the motor unit 1, but also increases the energy efficiency required to cool the oil O.

As shown in FIG. 19, the lower end of the second opening 68b is located above the liquid level of the oil O in the gear chamber 82 (upper limit height Lmin and lower limit height Lmin) regardless of whether the motor 2 is stationary or driven. Therefore, the second opening 68b is not submerged on the gear chamber 82 side. The second opening 68b can move the oil O to the gear chamber 82 regardless of the liquid level in the gear chamber 82, and can prevent the rotor 20 from being immersed in the oil O.

The change in the amount of oil O moving through the partition opening 68 as the level of the oil O pooled below the motor chamber 81 rises will now be described in more detail. Here, the level of the oil O pooled below the motor chamber 81 that reaches the lower end 68c of the second opening 68b is defined as the first liquid level OL. In other words, the lower end of the second opening 68b is located at the first liquid level OL. The first liquid level OL is located above the lower end of the stator 30 and below the lower end of the rotor 20.

Figure 16 is a graph showing the relationship between the height of the oil O that accumulates on the lower side of the motor chamber 81 and the area of the first region S. The area of the first region S is correlated (approximately proportional) to the flow rate of the oil O that flows out from the partition opening 68.

Oil O is supplied to the motor 2 as the motor 2 is driven, and begins to accumulate in the lower region of the motor chamber 81. The oil O accumulated in the lower region of the motor chamber 81 moves from the motor chamber 81 to the gear chamber 82 through the first opening 68a. When the amount of oil O supplied to the motor 2 per unit time exceeds the flow rate of oil O moving from the motor chamber 81 to the gear chamber 82 through the first opening 68a, the liquid level of the oil O accumulated in the lower region of the motor chamber 81 rises. When the liquid level reaches the first liquid level OL, the oil O flows out from the second opening 68b in addition to the first opening 68a. Since the second opening 68b has a larger width along the horizontal direction than the first opening 68a, the area of the first region S increases rapidly before and after the liquid level reaches the first liquid level OL. As a result, the flow rate of oil O flowing from the motor chamber 81 to the gear chamber 82 through the partition opening 68 increases rapidly. As described above, the first liquid level OL is set below the lower end of the rotor 20. Therefore, according to this embodiment, the rotation efficiency of the rotor 20 in the motor chamber 81 can be prevented from decreasing due to the flow resistance of the oil O.

The horizontal width of the second opening 68b is preferably set so that the flow rate of oil O flowing out of the partition opening 68 when the liquid level reaches above the first liquid level OL is greater than the oil O supplied to the motor 2 in the oil passage 90. This prevents the liquid level of the oil O accumulating in the lower region of the motor chamber 81 from significantly exceeding the first liquid level OL, and prevents the rotor 20 from being immersed in the oil O.

As shown in FIG. 1, the first oil passage 91 includes a scooping path 91a and an internal rotor path 91d. The scooping path 91a moves the oil O from the gear chamber 82 to the motor chamber 81 by the differential device 5 scooping up the oil O. The amount of oil O scooped up by the differential device 5 depends on the rotation speed of the differential device 5. Therefore, the scooping path 91a increases or decreases the amount of oil O moving to the motor chamber 81 depending on the vehicle speed. In addition, the internal rotor path 91d sucks the oil O from the gear chamber 82 side to the motor chamber 81 side by the centrifugal force of the rotor 20. The centrifugal force depends on the rotation speed of the rotor 20. Therefore, the internal rotor path 91d increases or decreases the amount of oil O moving to the motor chamber 81 depending on the vehicle speed. That is, the first oil passage 91 increases or decreases the amount of oil O moving to the motor chamber 81 depending on the vehicle speed.

On the other hand, the second oil passage 92 moves oil O from the gear chamber 82 to the motor chamber 81 by a pump (electric pump) 96. The amount of oil O supplied to the pump 96 is controlled based on, for example, the temperature measurement results of the motor 2. Therefore, the amount of oil O moving to the motor chamber 81 in the second oil passage 92 increases or decreases regardless of the vehicle speed.

The second oil passage 92 stops the supply of oil O to the motor 2 when the motor 2 is stationary. The second oil passage 92 also starts the movement of oil O to the motor chamber 81 when the motor 2 is started. This makes it possible to increase the liquid level in the oil reservoir P in the gear chamber 82 when the motor 2 is stopped. As a result, the rotation of the motor 2 immediately after starting causes the second gear 42, the third gear 43, and the ring gear 51 to rotate within the oil reservoir P, allowing the oil O to be distributed over the tooth surfaces.

According to this embodiment, the second oil passage 92 draws up oil O from the oil reservoir P regardless of the vehicle speed. Therefore, the second oil passage 92 can lower the oil level in the oil reservoir P even when the vehicle is traveling at low speed. This makes it possible to prevent the rotational efficiency of the gears in the gear chamber 82 from being reduced by the oil O in the oil reservoir P when the vehicle is traveling at low speed.

(Modification of Partition Wall Opening) Fig. 17 is a front view of a modified partition wall opening 168 that can be employed in this embodiment. Note that components that are the same as those in the above-described embodiment will be described using the same reference numerals. The modified partition wall opening 168 has an elongated hole portion 168a extending in the vertical direction, and a wide extension portion 168b that is connected to the elongated hole portion 168a above the elongated hole portion 168a. The lower end of the elongated hole portion 168a is located near the bottom 81a of the motor chamber 81. The elongated hole portion 168a overlaps with the motor shaft J2 when viewed from the vertical direction. The extension portion 168b is formed in a shape similar to that of the elongated hole portion 168a.
The extension portion 168b is wider in the horizontal direction than the elongated hole portion 168a. The extension portion 168b is rectangular in shape with the horizontal direction as the longitudinal direction in a plan view. The extension portion 168b has a lower end 168c extending in the horizontal direction. The lower end 168c is located at the first liquid level OL described above. In the partition opening 168, the region located below the liquid level of the oil O is called the first region S, and the region located above the liquid level is called the second region R.

Figure 18 is a graph showing the relationship between the height of the liquid level of oil O accumulating below the motor chamber 81 and the area of the first region S in this modified example. In this modified example, when the liquid level reaches the first liquid level OL, the oil O flows out from the expansion portion 168b in addition to the long hole portion 168a, and the area of the first region S increases rapidly. As a result, the flow rate of oil O flowing from the motor chamber 81 to the gear chamber 82 through the partition opening 168 increases rapidly. Since the first liquid level OL is set below the lower end of the rotor 20, it is possible to prevent the rotational efficiency of the rotor 20 from decreasing due to the flow resistance of the oil O.

(Liquid level of oil reservoir) As shown in FIG. 1, when the motor 2 is in the driving state, the pump 96 is driven to supply oil O from the oil reservoir P to the motor 2 through the first oil passage 91. When the motor 2 is in the driving state, the first oil passage 91 moves oil O from the oil reservoir P to the first reservoir 93 by the differential device 5 scooping up, and supplies oil O to the inside of the motor 2. That is, when the motor 2 is in the driving state, both the first oil passage 91 and the second oil passage 92 supply oil O from the oil reservoir P to the motor 2. Therefore, when the motor 2 is in the driving state, the liquid level of the oil reservoir P located in the area below the gear chamber 82 drops. Also, since the oil O supplied to the motor 2 accumulates in the space below the motor chamber 81, when the motor 2 is in the driving state, the liquid level of the oil O accumulated in the area below the motor chamber 81 rises.

On the other hand, when the motor 2 is stopped, the first oil passage 91 and the second oil passage 92 stop supplying oil O to the motor 2. As a result, the oil O that drips below the motor 2 temporarily collects in the lower region of the motor chamber 81, and then moves to the oil pool P in the lower region of the gear chamber 82 via the partition opening 68. Therefore, when the motor 2 is stopped, the liquid level of the oil O that collects in the lower region of the motor chamber drops, and the liquid level of the oil pool P located in the lower region of the gear chamber 82 rises.

Figure 19 is a side view showing the arrangement of each gear located inside the gear chamber 82. In addition, in Figure 19, the gear accommodating portion 62 of the housing 6 and the bearings supporting each shaft are omitted. As shown in Figure 19, according to this embodiment, the liquid level of the oil O stored in the oil reservoir P varies between an upper limit height Lmax and a lower limit height Lmin as the oil O is supplied to the oil passage 90 (the first oil passage 91 and the second oil passage 92). As shown in Figure 1, the first oil passage 91 is provided with a first reservoir 93. In addition, the second oil passage 92 is provided with a second reservoir 98 and a sub-reservoir 95 (omitted in Figure 1, see Figure 14). Furthermore, the oil O is stored in the lower area of the motor chamber 81 where the first oil passage 91 and the second oil passage 92 join. In this way, there are several locations in the first oil passage 91 and the second oil passage 92 where the oil O can accumulate. As a result, when the oil O is supplied to the motor 2, the oil O that accumulates in the oil pool P moves to a reservoir or the like in the above-mentioned path, and the liquid level of the oil pool P drops. As a result, the gears in the gear chamber 82 are exposed from the oil O in the oil pool P, and the rotational efficiency of the gears can be improved.

As shown in FIG. 19, the lower end of the second gear 42, which is the larger of the pair of gears (second gear 42 and third gear 43) that rotate around the intermediate shaft J4 and is connected to the motor 2, is located below the upper limit height Lmax of the liquid level. Also, the lower end of the second gear 42 is located above the lower limit height Lmin of the liquid level. Similarly, the lower end of the third gear 43, which is the smaller of the pair of gears (second gear 42 and third gear 43) that rotate around the intermediate shaft J4 and is connected to the differential device 5, is located below the upper limit height Lmax of the liquid level. Also, the lower end of the third gear 43 is located above the lower limit height Lmin of the liquid level.

The liquid level in the oil reservoir P reaches the upper limit height Lmax when the motor 2 is stopped and the supply of oil O from the oil reservoir P to the motor 2 is stopped. According to this embodiment, when the motor 2 is stopped, a portion of the second gear 42 and the third gear 43 can be immersed in the oil O in the oil reservoir P. As a result, when the motor 2 is driven, the oil O can be instantly distributed over the tooth surfaces of the second gear 42 and the third gear 43, improving the transmission efficiency between the gears.

The liquid level in the oil reservoir P reaches the lower limit height Lmin when the motor 2 is driven under high load and the supply of oil O from the oil reservoir P to the motor 2 is most promoted. According to this embodiment, when the motor 2 is driven, the second gear 42 and the third gear 43 are positioned above the liquid level in the oil reservoir P, so that the decrease in the rotational efficiency of the second gear 42 and the third gear 43 caused by the flow resistance of the oil O can be suppressed. This makes it possible to increase the drive efficiency of the motor unit 1.

The ring gear 51, which is provided in the differential device 5 and connected to the reduction gear 4 and rotates around the differential shaft J5, has its lower end located below the liquid level at the upper limit height Lmax and the lower limit height Lmin of the liquid level. According to this embodiment, regardless of fluctuations in the liquid level of the oil pool P, at least a portion of the ring gear 51 is located below the liquid level of the oil O in the oil pool P. Therefore, even if the motor 2 is driven and the liquid level in the oil pool P becomes low, the ring gear 51 can scoop up the oil O from the oil pool P and supply the oil O to the tooth surfaces of each gear in the gear chamber 82, thereby improving the torque transmission efficiency between each gear.

(Overview of oil passages) With reference to Figure 1, the flow of oil O in oil passage 90 associated with the drive of motor unit 1 will be described. When mounted on a hybrid vehicle or plug-in hybrid vehicle, motor unit 1 runs in one of three modes: engine mode, in which it is driven only by the engine; motor mode, in which it is driven only by motor 2; and hybrid mode, in which it is driven by both the engine and the motor.

In engine mode, the motor 2 is stopped, but the differential device 5 is driven by the engine, so oil O is scooped up from the oil reservoir P. The scooped up oil O accumulates in the first reservoir 93, but is not splashed toward the stator 30 because the rotor 20 does not rotate. Also, in engine mode, the pump 96 is not driven, and oil O is not supplied to the second oil passage 92.

In motor mode and hybrid mode, when the vehicle is climbing a slope, the output of motor 2 increases and the amount of heat generated by motor 2 increases. In such a case, the discharge volume of pump 96 is increased to supply more oil O to stator 30, accelerating cooling. On the other hand, when the vehicle is descending a slope (i.e., when there is no load on motor 2) or when motor 2 has not yet reached a high temperature, such as when the vehicle is starting or when used in cold climates, the discharge volume of pump 96 is reduced.

The second oil passage 92 can adjust the amount of oil supplied to the motor 2 by the pump 96 depending on the temperature of the motor 2, the drive mode of the vehicle, etc. According to this embodiment, the energy required to cool the motor 2 can be made more efficient. Such an effect can be achieved when the pump 96 is an electrically driven pump. The discharge amount of the pump 96 can be managed based on temperature data detected by a temperature sensor provided in the motor 2. In addition, by combining various data such as the vehicle's operating history, driving state, vehicle attitude, outside temperature, and the weight of occupants and luggage, it is possible to predict temperature changes in the motor 2. Based on the predicted value of this temperature change, the motor 2 may be managed to prevent it from becoming overheated.

According to this embodiment, the oil passage 90 supplies oil O to the stator 30 from multiple locations, so the entire stator 30 can be cooled efficiently. Also, according to this embodiment, the oil O functions as both a cooling oil and a lubricating oil. Therefore, there is no need to provide separate paths for the cooling oil and the lubricating oil, which can reduce costs.

(Measures against contamination in oil passages) The oil O used to cool the motor unit 1 is used to lubricate the differential device 5 and the reduction gear device 4. Therefore, there is a risk of contamination with metal powder and other contaminants generated by mechanical contact being mixed into the oil O. The contamination may deteriorate the fluidity of the oil O in the first oil passage 91 and the second oil passage 92. The contamination is removed by periodic replacement of the oil O. In addition, a means for capturing the contamination may be provided in either or both of the first oil passage 91 and the second oil passage 92. As an example, as shown in FIG. 9, a permanent magnet 98m may be installed in the second reservoir 98 to magnetically capture the contamination and suppress the diffusion of the contamination. In this case, the deterioration of the fluidity of the oil O can be suppressed.

(Arrangement of each shaft) The motor shaft J2, intermediate shaft J4, and differential shaft J5 extend parallel to each other along the horizontal direction. The intermediate shaft J4 and differential shaft J5 are located below the motor shaft J2. Therefore, the reduction gear 4 and differential gear 5 are located below the motor 2.

When viewed from the axial direction of the motor shaft J2, the line segment virtually connecting the motor shaft J2 and the intermediate shaft J4 is defined as the first line segment L1, the line segment virtually connecting the intermediate shaft J4 and the differential shaft J5 is defined as the second line segment L2, and the line segment virtually connecting the motor shaft J2 and the differential shaft J5 is defined as the third line segment L3.

According to this embodiment, the second line segment L2 extends along a substantially horizontal direction. That is, the intermediate shaft J4 and the differential shaft J5 are aligned along a substantially horizontal direction. Therefore, the reduction gear 4 and the differential gear 5 can be aligned along a horizontal direction, and the vertical dimension of the motor unit 1 can be reduced. In addition, the oil O scooped up by the differential gear 5 can be efficiently applied to the reduction gear 4. This allows the oil O to be supplied to the tooth surfaces of the gears constituting the reduction gear 4, thereby improving the transmission efficiency of the gears. Note that the diameter of the gears (second gear 42 and third gear 43) rotating around the intermediate shaft J4 is smaller than the diameter of the ring gear 51 rotating around the differential shaft J5. According to this embodiment, since the second line segment L2 extends along a substantially horizontal direction, the intermediate shaft J4 and the differential shaft J5 are arranged along a substantially horizontal direction. Therefore, depending on the height of the oil level in the oil pool P, only the ring gear 51 is immersed in the oil pool P, and the second gear 42 and the third gear 43 are not immersed in the oil pool P. Therefore, the ring gear 51 can scoop up the oil O in the oil pool P while suppressing a decrease in the rotational efficiency of the second gear 42 and the third gear 43. In this embodiment, the second line segment L2 being substantially horizontal means a direction within ±10° of the horizontal direction.

According to this embodiment, the angle α between the second line segment L2 and the third line segment L3 is 30°±5°. This makes it possible to increase the transmission efficiency of the oil O scooped up by the differential device 5 between the first gear 41 and the second gear 42, and to achieve the desired gear ratio. If the angle α exceeds 35°, it becomes difficult to supply the oil scooped up by the differential device to the gear (first gear) that rotates around the motor shaft. This may result in a decrease in the transmission efficiency between the first gear and the second gear. On the other hand, if the angle α is less than 25°, the output side gear in the transmission process cannot be made sufficiently large, making it difficult to achieve the desired gear ratio in the three shafts (motor shaft, intermediate shaft, and differential shaft).

According to this embodiment, the first line segment L1 extends along a substantially vertical direction. That is, the motor shaft J2 and the intermediate shaft J4 are aligned along a substantially vertical direction. Therefore, the motor 2 and the reduction gear 4 can be aligned along the vertical direction, and the horizontal dimension of the motor unit 1 can be reduced. In addition, by making the first line segment L1 substantially vertical, the motor shaft J2 can be arranged close to the differential shaft J5, and the oil O scooped up by the differential gear 5 can be supplied to the first gear 41 that rotates around the motor shaft J2. This can improve the transmission efficiency between the first gear 41 and the second gear 42. In this embodiment, the substantially vertical direction of the first line segment L1 refers to a direction within ±10° of the vertical direction.

The length L1 of the first line segment, the length L2 of the second line segment, and the length L3 of the third line segment satisfy the following relationship: L1:L2:L3=1:1.4-1.7:1.8-2.0. In addition, the reduction ratio in the reduction mechanism from the motor 2 to the differential device 5 is 8 or more and 11 or less. According to this embodiment, the desired gear ratio (8 or more and 11 or less) can be achieved while maintaining the positional relationship between the motor shaft J2, the intermediate shaft J4, and the differential shaft J5 as described above.

<Parking mechanism> Figure 20 is a diagram showing a parking mechanism 7 that can be employed in the motor unit 1 of this embodiment. The parking mechanism 7 is effective when the motor unit 1 is used in an electric vehicle (EV). In a manual transmission vehicle driven by an engine, in addition to activating the parking brake, the transmission can be set to a position other than neutral to apply a load to the engine and provide a braking effect. In an automatic transmission vehicle, in addition to activating the parking brake, the transmission can be locked by setting the shift lever to the parking position. On the other hand, in an electric vehicle, there is no braking mechanism for applying the brakes to the vehicle other than the parking brake, so the parking mechanism 7 is required for the motor unit 1.

The parking mechanism 7 consists of a ring-shaped parking gear 71, a parking pole 72, a parking rod 73, and a parking lever 74. The parking gear 71 is arranged coaxially with the second gear (intermediate gear) 42 and the third gear 43 and the intermediate gear. The parking gear 71 is fixed to the intermediate shaft 45. The parking pole 72 has a protrusion 72a that engages with a groove in the parking gear 71 to prevent the parking gear 71 from rotating. The parking rod 73 is connected to the parking pole 72 and moves the protrusion 72a along the radial direction of the parking gear. The parking lever 74 is connected to the parking rod 73 and drives the parking rod 73.

When the motor 2 is operating, the parking pole 72 retracts from the parking gear 71. On the other hand, when the shift lever is in the parking position, the parking pole 72 engages with the parking gear 71, preventing the parking gear 71 from rotating.

The parking pole 72 is controlled by a parking motor (not shown) connected to the parking lever. By using a parking motor, the parking mechanism 7 can be electrified, simplifying the components for driving the parking mechanism 7. In addition, by using a parking motor, the parking pole 72 can be driven by a push button, paddle lever, or the like, improving operability for the driver. Such a mechanism is called a shift-by-wire system. Note that the parking mechanism 7 may be changed from an electric type using a shift-by-wire system to a manual type. In other words, the driver may drive the parking pole by mechanically pulling a wire connected to the parking lever.

According to this embodiment, the parking mechanism 7 is provided on the intermediate shaft 45. As a result, in the torque transmission process from the motor 2 to the axle 55, the braking torque required to prevent the rotation of the parking gear 71 can be reduced compared to when the parking mechanism 7 is provided on a gear subsequent to the intermediate shaft. This allows the structure of the parking mechanism to be made smaller and lighter. Furthermore, if the parking mechanism 7 is electrically operated, a small parking motor can be used. Furthermore, if the parking mechanism is manually operated, the burden on the driver can be reduced.

Furthermore, according to this embodiment, the parking mechanism 7 is located below the reduction gear 4. Therefore, the parking pole 72 is immersed in the oil O in the oil reservoir P, and the oil O is interposed between the parking gear 71 and the protrusion 72a of the parking pole 72, allowing the protrusion 72a to be smoothly attached and detached. Note that the parking mechanism 7 of this embodiment is only one example, and other conventionally known structures may also be adopted. Furthermore, the parking mechanism 7 may be arranged to apply a braking force to the shaft 21 or ring gear 51 connected to the motor 2.

<Modification 1> <Disconnection mechanism> Figure 21 is a partial cross-sectional view showing the disconnection mechanism 107 of the motor unit 101 of modification 1. As modification 1, a modified motor unit 101 equipped with a disconnection mechanism 107 in the torque transmission path from the motor 2 to the axle 55 will be described. The main difference between the motor unit 101 of this modification is that the disconnection mechanism 107 is provided on the shaft 121 of the motor 2. Note that components that are the same as those in the above-mentioned embodiment will be described using the same reference numerals.

The disconnection mechanism 107 is provided when the motor unit 101 is mounted on a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHV). Hybrid electric vehicles and plug-in hybrid electric vehicles run in one of the following modes: engine mode, in which the vehicle is driven only by the engine; motor mode, in which the vehicle is driven only by the motor 2; and hybrid mode, in which the vehicle is driven by both the engine and the motor. In an electric vehicle running in engine mode, the disconnection mechanism 107 disconnects the power transmission mechanism of the motor unit 101 (the rotor 20 of the motor 2, the reduction gear 4, and the differential gear 5) from the axle 55 so that the motor 2 does not become a load when stopped.

As shown in FIG. 21, in this modified example, the shaft 121 has a first shaft portion 121A, a connecting shaft portion 121C, and a second shaft portion 121B that are aligned coaxially, and a separation mechanism 107 that is positioned between the connecting shaft portion 121C and the second shaft portion 121B. The first shaft portion 121A, the connecting shaft portion 121C, and the second shaft portion 121B are aligned in this order along the axial direction. In other words, the connecting shaft portion 121C is positioned between the first shaft portion 121A and the second shaft portion 121B.

The shaft 121 is a hollow shaft with a hollow section 122 therein having an inner circumferential surface extending along the motor axis J2. The hollow section 122 includes a first hollow section 122A located inside the first shaft section 121A, a second hollow section 122B located inside the second shaft section 121B, and a third hollow section 122C located inside the connecting shaft section 121C. The first hollow section 122A, the second hollow section 122B, and the third hollow section 122C are aligned along the axial direction and communicate with each other.

The first shaft portion 121A is disposed in the motor chamber 81 of the accommodation space 80. The first shaft portion 121A is located radially inside the stator 30 and passes through the rotor core 24 along the motor axis J2. The first shaft portion 121A has a first end portion 121e located on the output side (i.e., the reduction gear 4 side).

The first end 121e passes through an insertion hole 61f provided in the partition wall 61c from the motor chamber 81 side. A first hollow portion (second recess) 122A opens on the axial surface of the first end 121e. The first end 121e is rotatably supported by a first bearing 89 held in contact with the surface of the partition wall 61c facing the motor chamber 81 side. By holding the first bearing 89 in contact with the surface of the partition wall 61c facing the motor chamber 81 side, the axis alignment of the first shaft portion 121A can be performed at the motor chamber 81 side of the housing 6. This allows the axis alignment of the first shaft portion 121A to the stator 30 to be performed with high precision.

The connection shaft portion 121C is disposed inside the insertion hole 61f. The connection shaft portion 121C is rotatably supported by a second bearing 188A that is held in contact with the surface of the partition wall 61c facing the gear chamber 82. The second bearing 188A is a ball bearing. The connection shaft portion 121C is provided with a stepped surface 121q that faces the partition wall 61c. The stepped surface 121q contacts the inner ring of the second bearing 188A.

According to this modified example, the second bearing 188A is held on the surface of the partition wall 61c facing the gear chamber 82. Therefore, the connecting shaft portion 121C can be assembled to the first shaft portion 121A after the first shaft portion 121A is aligned. This simplifies the assembly process of the connecting shaft portion 121C.

The outer diameter of the second bearing 188A is larger than the outer diameter of the first bearing 89. When the disconnecting mechanism 107 is operating, a large load is applied to the second bearing 188A in the axial and circumferential directions. According to the second bearing 188A of this modified example, by making the diameter larger than that of the first bearing 89, sufficient strength can be ensured against the load when the disconnecting mechanism 107 is operating.

The connection shaft portion 121C has a second end portion 121f, a third end portion 121g, and a connection flange portion 121h.

The second end 121f protrudes toward the motor chamber 81. The second end 121f is located on the first shaft portion 121A side and is connected to the first end 121e of the first shaft portion 121A. The second end 121f is accommodated in the first hollow portion 122A that opens to the first end 121e. The outer peripheral surface of the second end 121f fits into the inner peripheral surface of the first hollow portion 122A. By fitting the second end 121f into the first hollow portion 122A, the connecting portion between the first end 121e and the second end 121f can be made smaller in the radial direction. This makes it possible to secure space for placing the first bearing 89 radially outside the first end 121e.

The third end 121g protrudes toward the gear chamber 82. The third end 121g is located on the opposite side of the second end 121f and on the second shaft portion 121B side. A first recess 121p is provided at the end of the third end 121g facing the axial direction. The connection flange portion 121h extends radially outward from the third end 121g. The diameter of the connection flange portion 121h is larger than the smallest diameter portion of the insertion hole 61f.

According to this modified example, the connecting shaft portion 121C is a separate member from the first shaft portion 121A. Therefore, by assembling the connecting shaft portion 121C to the first shaft portion 121A after the assembly process of the motor 2, the assembly can be performed in the same order as the assembly order when the disconnection mechanism 107 is not present. Accordingly, the shape of the parts other than the shaft 121 can be the same as when the disconnection mechanism 107 is not present. In other words, according to this modified example, parts can be made common between the motor unit 101 with the disconnection mechanism 107 and the motor unit 1 without the disconnection mechanism 107. In addition, since the assembly order can be the same regardless of the presence or absence of the disconnection mechanism 107, it is possible to suppress the complication of the part shape and the increase in the number of parts. Therefore, according to this modified example, a highly versatile and low-cost motor unit 101 can be provided.

The second shaft portion 121B is disposed in the gear chamber 82 of the accommodation space 80. The second shaft portion 121B has a fourth end 121i and a fifth end 121j.

The fourth end 121i is located on the third end 121g side of the connecting shaft portion 121C. The power transmission between the fourth end 121i and the connecting flange portion 121h of the connecting shaft portion 121C is selectively disconnected by the disconnecting mechanism 107.

The fourth end 121i is accommodated in a first recess 121p provided in the third end 121g.
A needle bearing (bearing) 121n is provided in the radial gap between the third end 121g and the fourth end 121i. That is, according to this modification, the second shaft portion 121B is rotatably supported by the connecting shaft portion 121C at the fourth end 121i. Therefore, according to this modification, when the second shaft portion 121B and the connecting shaft portion 121C are separated by the separation mechanism 107, stable holding can be achieved without impeding relative rotation. Note that this effect can be achieved when a first recess that accommodates the other of the third end 121g and the fourth end 121i is provided in one of the third end 121g and the fourth end 121i via the needle bearing 121n.

In this modified example, the needle bearing 121n is composed of multiple cylindrical members arranged in a ring shape, but other bearing mechanisms such as ball bearings may be used instead of the needle bearing 121n. However, by adopting needle bearings, the radial dimensions of the third end 121g and the fourth end 121i can be reduced, thereby making the motor unit 101 more compact.

As described above, the first shaft portion 121A, the connecting shaft portion 121C, and the second shaft portion 121B each have a hollow portion 122 that extends in the axial direction and communicates with each other. As in the above-described embodiment, oil O that cools the inside of the motor is supplied to the hollow portion 122 from the second shaft portion 121B side toward the first shaft portion 121A side. According to this modified example, the connecting shaft portion 121C and the second shaft portion 121B are connected via a needle bearing 121n. Therefore, the third hollow portion 122C of the connecting shaft portion 121C and the second hollow portion 122B of the second shaft portion 121B can be connected to each other. This allows oil O to be supplied to the hollow portion 122 to be used as an oil flow path.

The fifth end 121j is located on the opposite side of the fourth end 121i. The fifth end is rotatably supported by a third bearing 188B held in the housing. That is, the second shaft portion 121B is supported by the third bearing 188B at the fifth end 121j. According to this modification, the second shaft portion 121B is supported by two bearings (needle bearing 121n and third bearing 188B) aligned in the axial direction. Similarly, the connecting shaft portion 121C is supported by two bearings (second bearing 188A and needle bearing 121n) aligned in the axial direction. The second shaft portion 121B and the connecting shaft portion 121C can rotate stably without axial wobble by being rotatably supported at two points aligned in the axial direction.

A first gear 41 is provided on the outer circumferential surface of the second shaft portion 121B. The first gear 41 is located between the fourth end 121i and the fifth end 121j. The first gear 41 transmits power to the second gear 42 of the reduction gear 4. According to this modified example, the first gear 41 is located between the second bearing 188A and the third bearing 188B. Therefore, the first gear 41 can rotate stably relative to the motor shaft J2, and the torque generated by the motor 2 can be stably transmitted to the second gear 42.

The disconnection mechanism 107 surrounds the connection flange portion 121h of the connection shaft portion 121C and the fourth end portion 121i of the second shaft portion 121B from the radially outer side. The disconnection mechanism 107 uses the drive unit 175 to switch between a state in which the connection flange portion 121h and the fourth end portion 121i are mechanically not connected to a state in which they are connected.

The disconnecting mechanism 107 is located between the axial end face of the motor 2 and the first gear 41 in the axial direction. The motor unit 101 adopts a three-shaft structure of the motor shaft J2, the intermediate shaft J4, and the differential shaft J5. In addition, the third gear 43 is located between the axial end face of the motor 2 and the first gear 41 in the axial direction. The second gear 42 rotates synchronously with the second gear 42 connected to the first gear 41. A gap larger than the thickness of the third gear 43 is provided between the axial end face of the motor 2 and the first gear 41. According to this modified example, the disconnecting mechanism 107 is disposed between the axial end face of the motor 2 and the first gear 41. That is, the third gear 43 and the disconnecting mechanism 107 are disposed in a position where they overlap in the axial direction. This makes it possible to effectively utilize the internal space of the gear chamber 82 and to reduce the size of the motor unit 101.

According to this modified example, the disconnection mechanism is provided on the shaft 121 of the motor 2. In other words, the disconnection mechanism 107 is provided at the part of the power transmission path from the motor 2 to the axle 55 where the torque is the smallest. According to this modified example, the torque transmitted via the disconnection mechanism 107 is small, so the disconnection mechanism can be made smaller.

The decoupling mechanism 107 in this modified example is called a rotational synchronization device or a synchromesh mechanism. Note that in this modified example, the decoupling mechanism 107 is just one example. For example, a dog clutch mechanism or a multi-stage clutch mechanism may be used as the decoupling mechanism.

The disconnection mechanism 107 has a sleeve 171, a clutch hub 172, a synchronizer ring 173, a key 174, and a drive unit (not shown).

The clutch hub 172 is fixed to the outer circumferential surface of the second shaft portion 121B. The clutch hub 172 rotates together with the second shaft portion 121B about the motor shaft J2. An external spline is provided on the outer periphery of the clutch hub 172.

The sleeve 171 is movable along the axial direction. The sleeve 171 meshes with the external splines of the clutch hub 172 and rotates integrally with the sleeve 171. In addition, the inner peripheral surface of the sleeve 171 is provided with splines. The splines of the sleeve 171 fit into the splines provided on the outer peripheral surface of the connection flange portion 121h after the clutch hub 172 and the connection flange portion 121h rotate synchronously. This connects the second shaft portion 121B and the connection shaft portion 121C.

The key 174 is held in the sleeve 171. The key 174 moves axially together with the sleeve 171. The key 174 aligns the phases of the splines provided on the sleeve 171 and the connection flange portion 121h.

The synchronizer ring 173 moves in the axial direction together with the sleeve 171. The synchronizer ring 173 has a tapered surface whose inner diameter increases as it approaches the connection flange portion 121h. Meanwhile, the connection flange portion 121h is provided with a boss portion that protrudes toward the synchronizer ring 173 along the axial direction. The boss portion is provided with a tapered surface that faces the synchronizer ring 173. The synchronizer ring 173 and the connection flange portion 121h rotate synchronously by bringing their tapered surfaces into contact with each other.

The drive unit (not shown) is connected to the sleeve 171. The drive unit moves the sleeve 171 in the axial direction.

Figure 22 is a conceptual diagram showing the state in which the motor 2 and the reduction gear 4 are connected by the disconnection mechanism 107, and Figure 23 is a conceptual diagram showing the state in which the motor 2 and the reduction gear 4 are disconnected by the disconnection mechanism 107. As described above, the motor unit 101 equipped with the disconnection mechanism 107 is mounted on a hybrid vehicle or a plug-in hybrid vehicle. In such a vehicle, when switching between a mode in which the vehicle runs only on engine power and a mode in which the vehicle runs using the power of the motor 2, the drive unit 175 operates to switch between connection and disconnection between the connection shaft portion 121C and the second shaft portion 121B.

The control of the disconnection mechanism 107 will be described. When the disconnection mechanism 107 switches from the disconnected state to the connected state, first, the rotation speed of the second shaft portion 121B is calculated from the rotation speed of the axle 55. Next, the rotation speed of the motor 2 is increased to the calculated rotation speed of the second shaft portion 121B. While the rotation speed of the motor 2 is increasing, the sleeve is moved by the drive unit 175, and the connection between the second shaft portion 121B and the connection shaft portion 121C is realized. After that, the position where the connection between the second shaft portion 121B and the connection shaft portion 121C is completed is calculated from the cumulative rotation speed of the drive unit 175. Finally, it is detected that the rotation speed of the motor 2 and the rotation speed of the second shaft portion 121B calculated from the rotation speed of the axle 55 are the same, and it is finally determined that the joining state is completed.

<Control> Each element, such as the motor 2 of the motor unit 1, the pump 96, the drive unit 175 of the disconnection mechanism 107, and the parking motor of the parking mechanism 7, is centrally controlled by a micro control unit (MCU). The micro control unit may be provided integrally with the motor unit 1 or externally.

<Mountability in vehicle> The motor unit 1 can be applied to any of hybrid vehicles (HEVs), plug-in hybrid vehicles (PHVs), and electric vehicles (EVs). The motor unit 1 can also be applied to freight vehicles (trucks) and the like, not just passenger cars. The motor unit 1 can be mounted on either the front or rear side of the vehicle, but is preferably mounted on the rear side. The motor unit 1 of this embodiment has small vertical dimensions, so it can be installed compactly even on the rear side, where installation space is limited due to restrictions on the luggage compartment and minimum ground clearance.

The above describes the embodiments and variations of the present invention, but each configuration and their combinations in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications of configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

Reference Signs List 1,101...motor unit (electric drive device), 2...motor, 4...reduction gear, 5...differential gear, 6...housing, 6a...wall portion, 20...rotor, 21,121...shaft, 21A,121A...first shaft portion, 21B,121B...second shaft portion, 21c...flange portion, 21c...flange portion (cover portion), 21d...thread portion, 21e,121e...first end portion, 21f,121f...second end portion, 21g,121g...third end portion, 21h,121i...fourth end portion, 22,122...hollow portion, 22A,122A...first hollow portion, 22q...second region (small diameter hollow portion), 22r...second 3 region (large diameter hollow portion), 22t... second step surface (step surface), 22u... groove, 23... communication hole, 24... rotor core, 24a... axial end surface, 24b... outer circumferential surface, 24d... magnet holding hole, 24e... core through hole, 25... rotor magnet, 26, 126, 226... end plate, 26a, 126a, 226a... first surface, 26b, 126b, 226b... second surface, 26e, 126u... inclined surface, 26f, 61j, 61q... recess, 26j, 126j, 226j... first groove (first recess), 26k, 126k, 226k, 226kA, 226kB ...second groove (second recess), 26p, 126p, 226p...plate through hole, 26r...second open portion (open portion), 26s...first open portion (open portion), 26t...oil flow path, 28...washer (lid portion), 29...nut, 30...stator, 31...coil, 31a...coil end, 32...stator core, 41...first gear, 42...second gear (intermediate gear), 43...third gear, 51...ring gear, 61...motor accommodating portion, 61c...partition wall, 61f...insertion hole, 61k, 97b, 98r, 98o, 98x, 98t, 98u, 98v, 198c...flow Outlet, 63...blocking portion, 63d...protruding portion, 64...gear chamber ceiling portion (ceiling portion), 65...convex portion, 66...eaves portion, 68, 168...partition wall opening, 68a...first opening, 68b...second opening, 80...accommodation space, 81...motor chamber, 82...gear chamber, 88, 188A...second bearing, 89...first bearing, 90...oil passage, 91...first oil passage (oil passage), 91a...pick-up passage, 91b...shaft supply passage (oil passage), 92...second oil passage (oil passage), 92a...first passage, 92b...second passage, 92c, 92aa, 92ba, 92ca...first end portion,
92ab, 92bb, 92cb... second end, 97c... third flow path, 93... first reservoir (reservoir), 95... secondary reservoir, 96... pump (electric pump), 96a... intake port, 97... cooler, 98, 198... second reservoir (main reservoir), 98y... overflow portion, 99... supply portion, 107... disconnection mechanism, 121C... connection shaft portion, 121h... connection flange portion, 121j... fifth end, 121n... needle bearing ing (bearing), 121p...first recess, 121q...step surface, 126r, 226r...opening portion, 128, 228...lid portion, 168a...long hole portion, 168b...expansion portion, 98gC...dam, J2...motor shaft, J4...intermediate shaft, J5...differential shaft, L1...first line segment, L2...second line segment, L3...third line segment (imaginary line), Lmax...upper limit height, Lmin...lower limit height, O...oil, OL...first liquid level, P...oil reservoir, S...first region

Claims (11)

A motor;
a plurality of gears for transmitting torque of the motor;
a housing having an accommodation space for accommodating the motor and the plurality of gears;
Oil collected in an oil reservoir provided in a vertically lower region of the storage space;
an oil passage for supplying the oil from the oil sump to the motor and recovering the oil in the oil sump;
The housing has a partition wall.
the partition divides the accommodation space into a motor chamber in which the motor is accommodated and a gear chamber in which the plurality of gears are accommodated,
The partition wall has a partition wall opening that communicates between the gear chamber and the motor chamber,
The bottom of the motor chamber is located above the bottom of the gear chamber,
The oil reservoir is provided in a lower area of the gear chamber,
An electric pump and a cooler are provided in the oil passage,
The oil passage is
a first flow passage connecting the oil reservoir and the electric pump;
a second flow passage connecting the electric pump and the cooler;
a third flow passage connecting the cooler and the motor chamber,
the second flow path passes through an interior of a portion of the wall of the housing that is located on a horizontal side of the motor,
the third flow path passes through an interior of a portion of the wall of the housing that is positioned above the motor,
The motor has a rotor that rotates around a motor shaft,
The plurality of gears constitute a reduction gear device and a differential device,
The cooler is fixed to an outer circumferential surface of the housing,
When viewed from the axial direction, the cooler and the differential device are located on opposite sides of the motor shaft.
Motor unit. A motor;
A plurality of gears for transmitting torque of the motor;
a housing having an accommodation space for accommodating the motor and the plurality of gears;
Oil collected in an oil reservoir provided in a vertically lower region of the storage space;
an oil passage for supplying the oil from the oil sump to the motor and recovering the oil in the oil sump;
The housing has a partition wall,
the partition divides the accommodation space into a motor chamber in which the motor is accommodated and a gear chamber in which the plurality of gears are accommodated,
The partition wall has a partition wall opening that communicates between the gear chamber and the motor chamber,
The bottom of the motor chamber is located above the bottom of the gear chamber,
The oil reservoir is provided in a lower area of the gear chamber,
An electric pump is provided in the oil passage,
the oil passage connects the oil reservoir and the electric pump, and also connects the electric pump and the motor chamber;
the housing has a cylindrical peripheral wall portion that fits along an outer circumferential surface of the motor,
A recess is provided on an inner circumferential surface of the peripheral wall portion, the recess being recessed radially outward,
The recess extends along an axial direction,
At least a portion of the partition opening opens into the recess.
Motor unit. A cooler is provided in the oil passage.
The motor unit according to claim 2 . The electric pump and the cooler are fixed to an outer circumferential surface of the housing.
The motor unit according to claim 3 . The electric pump and the cooler are arranged vertically,
The cooler is located above the electric pump,
The cooler overlaps with the electric pump when viewed in a vertical direction.
5. A motor unit according to claim 1 or 4 . At least a portion of the oil passage passes through an interior of a wall of the housing.
The motor unit according to any one of claims 1 to 5 . the oil passage has a first flow path connecting the oil reservoir and the electric pump,
The first flow path passes through an interior of a portion of the wall portion that is located below the motor.
The motor unit according to claim 6 . At least a portion of the oil passage passes through an interior of a wall of the housing;
A cooler is provided in the oil passage,
the oil passage has a second flow passage connecting the electric pump and the cooler,
The second flow path passes through an interior of a portion of the wall portion that is located on a horizontal side of the motor.
The motor unit according to any one of claims 2 to 4 . At least a portion of the oil passage passes through an interior of a wall of the housing;
A cooler is provided in the oil passage,
The oil passage has a third flow passage connecting the cooler and the motor chamber,
The third flow path passes through an interior of a portion of the wall portion located above the motor.
A motor unit according to any one of claims 2 to 4 and 8 . The plurality of gears constitute a reduction gear device and a differential device,
the oil passage has a first flow path connecting the oil reservoir and the electric pump,
the first flow path has a first end and a second end;
the first end is located upstream of the first flow path relative to the second end,
The first end opens into the accommodation space below the differential gear.
The motor unit according to any one of claims 1 to 9 . The lower end of the partition opening is located below the lower end of the motor.
The motor unit according to any one of claims 1 to 10 .

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