Drive unit

Abstract

To provide a driving device having a high effective coolant path.SOLUTION: A driving device 1 comprises: a motor 2 that has a motor shaft 21; a power transmission device 3 that is connected from one side of an axial direction to a motor shaft 21; a housing 6 that has a motor accommodation part 81 accommodating the motor 2 into an inner part and a gear accommodation part 82 housing the power transmission device 3 into the inner part; a coolant O that is accommodated into the inner part of the housing 6; a coolant path 90 in which the coolant O is circulated; a cooler 9 that cools the coolant O; and a pump 8 that transmits the coolant O with the pressure. The coolant path 90 includes: a first flow channel 91 that connects a coolant reservoir P1 in the housing 6 and a suction port 8a of the pump 8; a second flow channel 92 that connects a discharge port 8b of the pump 8 and an inlet port 9a of the cooler 9; and a third flow channel 93 that is extended to the inner part of the motor accommodation part 81 from an outlet port 9b of the cooler 9 and supplies the coolant O to the motor 2. The cooler 9 is fixed to an outer side surface of the housing 6 in a region overlapped with at least one part of the gear accommodation part 82 and the radial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In an electric vehicle or a hybrid vehicle, a cooling circuit for cooling a motor, a battery, etc. is mounted. Patent Document 1 discloses a cooling system that cools an electric motor by an oil circulation circuit that circulates oil for cooling. In Patent Document 1, the oil in the oil circulation circuit passes through a pipe arranged above the stator. The pipe is provided with discharge holes, and the oil is supplied from the discharge holes to the stator to cool the stator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a refrigerant path for cooling a motor, when the pressure loss of the refrigerant in the path increases, the power consumption of the pump for pumping the refrigerant increases, or the pump becomes larger. Therefore, it is required to configure an efficient refrigerant path by shortening the path length or the like.

[0005] In view of the above circumstances, one object of the present invention is to provide a drive device having an efficient refrigerant path.

Means for Solving the Problems

[0006] One aspect of the drive device of the present invention comprises a motor having a motor shaft that rotates about a motor axis, a power transmission mechanism connected to the motor shaft from one axial side, a housing having a motor housing section that houses the motor and a gear housing section that houses the power transmission mechanism, a refrigerant housed inside the housing, a refrigerant path through which the refrigerant circulates, a cooler that cools the refrigerant, and a pump that pumps the refrigerant. The refrigerant path has a first flow path connecting a refrigerant reservoir in the housing to the inlet of the pump, a second flow path connecting the discharge port of the pump to the inlet of the cooler, and a third flow path extending from the outlet of the cooler into the motor housing section to supply the refrigerant to the motor. The cooler is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing section. [Effects of the Invention]

[0007] According to one aspect of the present invention, a drive device having an efficient refrigerant path can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of the drive device of the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view of a modified example of the first embodiment, showing a hollow shaft and partition wall. [Figure 3] Figure 3 is a schematic diagram of the drive device of the second embodiment. [Figure 4] Figure 4 is a schematic diagram showing the configuration of the second and fourth flow channels in the second embodiment. [Figure 5] Figure 5 is a schematic diagram showing the configuration of the second and fourth flow channels in a modified example of the second embodiment. [Figure 6] Figure 6 is a schematic diagram of the drive device of the third embodiment. [Figure 7] Figure 7 is a schematic diagram of the drive device of the fourth embodiment. [Figure 8]Figure 8 is a schematic diagram of the drive unit of the fifth embodiment. [Figure 9] Figure 9 is a schematic diagram of the drive device according to the sixth embodiment. [Figure 10] Figure 10 is a schematic diagram of the drive unit of the seventh embodiment. [Figure 11] Figure 11 is a schematic diagram of the drive device of the eighth embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, an embodiment of the drive device of the present invention will be described with reference to the drawings. In the following description, the vertical direction is defined and explained based on the positional relationship when the drive unit of each embodiment shown in the figures is mounted on a vehicle located on a horizontal road surface. In the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction will be simply referred to as "upper side," and the lower side in the vertical direction will be simply referred to as "lower side." The X axis direction is the direction perpendicular to the Z axis direction and is the longitudinal direction of the vehicle on which the drive unit is mounted. In the following embodiments, the +X side is the front side of the vehicle, and the -X side is the rear side of the vehicle. The Y axis direction is the direction perpendicular to both the X axis direction and the Z axis direction and is the lateral direction of the vehicle, i.e., the vehicle width direction. In the following embodiments, the +Y side is the left side of the vehicle, and the -Y side is the right side of the vehicle. The longitudinal direction and the lateral direction are horizontal directions perpendicular to the vertical direction.

[0010] The motor axis J2, as shown appropriately in each figure, extends in the Y-axis direction, that is, in the left-right direction of the vehicle. In the following explanation, unless otherwise specified, the direction parallel to the motor axis J2 will be simply called the "axial direction," the radial direction centered on the motor axis J2 will be simply called the "radial direction," and the circumferential direction centered on the motor axis J2, that is, around the axis of the motor axis J2, will be simply called the "circumferential direction." Also, in the following explanation, the +Y side may be simply called one axial side, and the -Y side may be simply called the other axial side.

[0011] <First Embodiment> FIG. 1 is a schematic diagram of a drive device according to the first embodiment. The drive device 1 is mounted on a vehicle having 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 its power source.

[0012] The drive device 1 includes a motor 2, a power transmission mechanism 3, a housing 6, an inverter 7, a cooler 9, a pump 8, a refrigerant O, and a refrigerant path 90 through which the refrigerant O circulates.

[0013] The housing 6 has a motor housing portion 81 that houses the motor 2 therein, a gear housing portion 82 that houses the power transmission mechanism 3 therein, and an inverter housing portion 89 that houses the inverter 7. The gear housing portion 82 is located on one axial side (+Y side) of the motor housing portion 81. The inverter housing portion 89 is located above the motor housing portion 81.

[0014] (Motor) In the present embodiment, the motor 2 is an inner rotor type motor. Also, the motor 2 of the present embodiment is, for example, a three-phase AC motor. The motor 2 has both a function as an electric motor and a function as a generator. The motor 2 includes a motor shaft 21, a rotor 20, and a stator 30.

[0015] The motor shaft 21 extends axially along the motor axis J2. The motor shaft 21 rotates about the motor axis J2. The motor shaft 21 is a hollow shaft having a hollow portion 22 extending axially therein.

[0016] The motor shaft 21 extends across the motor housing portion 81 and the gear housing portion 82 of the housing 6. The motor shaft 21 is connected to the rotor 20 inside the motor housing portion 81. The motor shaft 21 is connected to the power transmission mechanism 3 inside the gear housing portion 82. That is, the power transmission mechanism 3 is connected to the motor shaft 21 from one axial side (+Y side). The motor shaft 21 is rotatably supported by the housing 6 via a bearing (not shown).

[0017] The rotor 20 is fixed to the outer peripheral surface of the motor shaft 21. The rotor 20 is rotatable about a motor axis J2 extending in the horizontal direction. The rotor 20 has a rotor core 24 and a rotor magnet (not shown) fixed to the rotor core. The torque of the rotor 20 is transmitted to the power transmission mechanism 3.

[0018] The stator 30 surrounds the rotor 20 from the radially outer side. 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 by the housing 6. The stator core 32 has a plurality of magnetic pole teeth (not shown) extending radially inward from the inner peripheral surface of an annular yoke. Coil wires are arranged between the magnetic pole teeth. The coil wires located in the gaps between adjacent magnetic pole teeth constitute the coil 31. The insulator is made of an insulating material.

[0019] (Power Transmission Mechanism) The power transmission mechanism 3 has a plurality of gears 41, 42, 43, 51. The power transmission mechanism 3 is connected to the rotor 20 of the motor 2 to transmit power. The power transmission mechanism 3 has a reduction gear 4 and a differential gear 5.

[0020] The reduction gear 4 has a 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 is connected to the motor shaft 21. The reduction gear 4 transmits the torque output from the motor 2 to the differential gear 5.

[0021] The reduction gear 4 includes a pinion gear 41, an intermediate shaft 45, and a counter gear 42 and a drive gear 43 fixed to the intermediate shaft 45. The torque output from the motor 2 is transmitted to the ring gear 51 of the differential gear 5 via the motor shaft 21, pinion gear 41, counter gear 42, and drive gear 43. The gear ratios of each gear and the number of gears can be changed in various ways according to the required reduction ratio.

[0022] The pinion gear 41 is fixed to the outer surface of the motor shaft 21. The pinion gear 41 rotates together with the motor shaft 21 around the motor axis J2.

[0023] The intermediate shaft 45 extends along an intermediate axis J4 parallel to the motor axis J2. The intermediate shaft 45 rotates about the intermediate axis J4.

[0024] The counter gear 42 and the drive gear 43 are arranged side by side in the axial direction. The counter gear 42 and the drive gear 43 are mounted on the outer circumferential surface of the intermediate shaft 45. The counter gear 42 and the drive gear 43 are connected via the intermediate shaft 45. The counter gear 42 and the drive gear 43 rotate about the intermediate axis J4. At least two of the counter gear 42, the drive gear 43, and the intermediate shaft 45 may be composed of a single component. The counter gear 42 meshes with the pinion gear 41. The drive gear 43 meshes with the ring gear 51 of the differential 5.

[0025] The differential gear 5 is a device for transmitting torque output from the motor 2 to the vehicle's wheels. The differential gear 5 has the function of absorbing the speed difference between the left and right wheels when the vehicle turns, while transmitting the same torque to a pair of output shafts 55.

[0026] The differential gear 5 includes a ring gear (scraper gear) 51, a gear housing (not shown), 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 about a differential axis J5 that is parallel to the motor axis J2. Torque output from the motor 2 is transmitted to the ring gear 51 via the reduction gear 4.

[0027] A pair of output shafts 55 extend along the axial direction. A side gear is connected to one end of each output shaft 55, and a wheel is connected to the other end. The pair of output shafts 55 transmit the torque of the motor 2 to the road surface via the wheels.

[0028] (housing) The housing 6 comprises a housing body 83, a motor cover 84, a gear cover 85, and an inverter cover 86. The housing body 83, motor cover 84, gear cover 85, and inverter cover 86 are each separate components. The motor cover 84 is located on the other axial side (-Y side) of the housing body 83. The gear cover 85 is located on one axial side (+Y side) of the housing body 83. The inverter cover 86 is located on the upper side of the housing body 83.

[0029] The housing 6 has a motor housing section 81, a gear housing section 82, and an inverter housing section 89. The motor housing section 81, the gear housing section 82, and the inverter housing section 89 are composed of the housing body 83, the motor cover 84, the gear cover 85, and the inverter cover 86, respectively.

[0030] The motor housing section 81 is composed of a cylindrical portion of the housing body 83 and a motor cover 84 that covers the opening on the other axial side (-Y side) of the cylindrical portion. The motor 2 is positioned in the space enclosed by the housing body 83 and the motor cover 84.

[0031] The gear housing 82 is composed of a concave portion that opens on one axial side (+Y side) of the housing body 83 and a gear cover 85 that covers the opening of this concave portion. The power transmission mechanism 3 is arranged in the space enclosed by the housing body 83 and the gear cover.

[0032] The inverter housing 89 is composed of a box-shaped section that opens on the upper side of the housing body 83 and an inverter cover 86 that covers the opening of this box-shaped section. The inverter 7 is placed in the space enclosed by the housing body 83 and the inverter cover 86.

[0033] The housing 6 includes a gear cover wall portion (cover wall portion) 6a, a partition wall 6b, and a motor cover wall portion 6c extending along a plane perpendicular to the motor axis J2, a gear peripheral wall portion 6f surrounding the power transmission mechanism 3 from the radially outer side, and a motor peripheral wall portion 6g surrounding the motor 2 from the radially outer side.

[0034] The gear cover wall portion 6a is provided on the gear cover 85. The gear cover wall portion 6a constitutes a part of the gear housing portion 82. The gear cover wall portion 6a is positioned on one axial side (+Y side) of the power transmission mechanism 3.

[0035] The motor cover wall portion 6c is provided on the motor cover 84. The motor cover wall portion 6c constitutes a part of the motor housing portion 81. The motor cover wall portion 6c is positioned on the other axial side (-Y side) of the motor 2.

[0036] The partition wall 6b is provided in the housing body 83. The partition wall 6b separates the internal space of the motor housing 81 from the internal space of the gear housing 82. The partition wall 6b constitutes part of the motor housing 81 and the gear housing 82. The partition wall 6b is provided with a shaft passage hole 6p and a partition wall opening 6q. The shaft passage hole 6p and the partition wall opening 6q connect the internal spaces of the motor housing 81 and the gear housing 82. The motor shaft 21 passes through the shaft passage hole 6p.

[0037] The gear peripheral wall portion 6f is composed of a part of the housing body 83 and a part of the gear cover 85. The gear peripheral wall portion 6f constitutes a part of the gear housing portion 82. The gear peripheral wall portion 6f extends along the axial direction. The gear peripheral wall portion 6f connects the gear cover wall portion 6a and the partition wall 6b. The gear peripheral wall portion 6f surrounds the gears 41, 42, 43, and 51 from the radially outer side of the motor axis J2, intermediate axis J4, and differential axis J5.

[0038] The motor peripheral wall portion 6g is provided on the housing body 83. The motor peripheral wall portion 6g constitutes a part of the motor housing portion 81. The motor peripheral wall portion 6g is cylindrical in shape and extends axially with respect to the motor axis J2. The motor peripheral wall portion 6g connects the partition wall 6b and the motor cover wall portion 6c. The motor peripheral wall portion 6g surrounds the motor 2 from the radially outer side of the motor axis J2.

[0039] The housing 6 contains refrigerant O. The refrigerant O circulates within the refrigerant path 90, which will be described later. In this embodiment, refrigerant O is an oil and is used not only for cooling the motor 2 but also for lubricating the power transmission mechanism 3. As refrigerant O, it is preferable to use an oil equivalent to automatic transmission fluid (ATF) with relatively low viscosity in order to perform the functions of both lubricant and coolant.

[0040] In the lower region of the housing 6, refrigerant reservoirs P1 and P2 are provided where refrigerant O accumulates. In this embodiment, refrigerant O accumulates in the lower regions of the gear housing 82 and the motor housing 81, respectively. In the following description, the lower region of the gear housing 82 will be referred to as the first refrigerant reservoir P1, and the lower region of the motor housing 81 will be referred to as the second refrigerant reservoir P2. The refrigerant O accumulated in the first refrigerant reservoir P1 is stirred up by the operation of the power transmission mechanism 3 and diffused into the gear housing 82.

[0041] The refrigerant O diffused within the gear housing 82 is supplied to each gear of the power transmission mechanism 3 within the gear housing 82, spreading the refrigerant O across the gear tooth surfaces. The refrigerant O supplied to the power transmission mechanism 3 and used for lubrication is collected by dripping into the first refrigerant reservoir P1 within the gear housing 82.

[0042] The refrigerant O in the first refrigerant reservoir P1 is sent into the motor housing 81 via a refrigerant path 90, which will be described later. The refrigerant O sent into the motor housing 81 drips from the motor 2 and accumulates in the second refrigerant reservoir P2. A portion of the refrigerant O accumulated in the second refrigerant reservoir P2 moves to the gear housing 82 through the partition opening 6q and returns to the first refrigerant reservoir P1.

[0043] In this specification, "a refrigerant is contained inside a certain part" means that the refrigerant is located inside the certain part for at least a portion of the time while the motor is running, and does not need to be located inside the certain part when the motor is stopped. For example, in this embodiment, "a refrigerant O is contained inside the motor housing 81" means that the refrigerant O is located inside the motor housing 81 for at least a portion of the time while the motor 2 is running, and when the motor 2 is stopped, all of the refrigerant O inside the motor housing 81 may move to the gear housing 82 through the partition opening 6q. In addition, a portion of the refrigerant O sent into the motor housing 81 by the refrigerant path 90, which will be described later, may remain inside the motor housing 81 when the motor 2 is stopped.

[0044] (Refrigerant path) The refrigerant O circulates within the drive unit 1 through the refrigerant path 90. The refrigerant path 90 is a path that supplies refrigerant O from the first refrigerant reservoir P1 to the motor 2 and returns the refrigerant O back to the first refrigerant reservoir P1.

[0045] In this specification, "refrigerant path" means the path of refrigerant O circulating within (or inside and outside) the housing 6. Therefore, "refrigerant path" is a concept that includes not only "flow paths" that form a steady flow of refrigerant in a steady direction, but also paths that temporarily retain refrigerant (for example, those that function as catch tanks), paths through which refrigerant drips, and paths through which refrigerant is scattered.

[0046] The refrigerant path 90 includes a pump 8, a cooler 9, and a supply pipe 93A. The pump 8 and the cooler 9 are fixed to the outer surface of the housing 6, respectively. The supply pipe 93A is positioned directly above the motor 2 inside the motor housing 81.

[0047] Cooler 9 cools the refrigerant O in the refrigerant path 90. Inside cooler 9, there are internal passages (not shown) through which the refrigerant O flows and internal passages (not shown) through which cooling water flows. Cooler 9 is a heat exchanger that cools the refrigerant O by transferring its heat to the cooling water. Cooler 9 has an inlet 9a and an outlet 9b. The refrigerant O flows into the internal passage of cooler 9 from inlet 9a and flows out from outlet 9b.

[0048] Pump 8 is an electrically driven electric pump. Pump 8 may also be a mechanical pump that operates in conjunction with the drive of the power transmission mechanism 3. Pump 8 pumps the refrigerant O in the refrigerant path 90. Pump 8 has an inlet 8a and a discharge port 8b. The refrigerant O is drawn into the pump 8 from the inlet 8a and discharged from the discharge port 8b.

[0049] The refrigerant path 90 in this embodiment has a first flow path 91, a second flow path 92, and a third flow path 93. The entire length of the first flow path 91 and the second flow path 92, and a portion of the third flow path 93, are holes provided in the housing 6. The entire length of the first flow path 91 and the second flow path 92, and a portion of the third flow path 93, are formed by drilling holes in the wall of the housing 6. The other portion of the third flow path 93 is provided inside the supply pipe 93A.

[0050] The first flow path 91 connects the first refrigerant reservoir P1 of the housing 6 to the suction port 8a of the pump 8. The upstream end of the first flow path 91 opens into the first refrigerant reservoir P1. The first flow path 91 is located inside the gear cover wall 6a of the gear cover 85, along its wall surface.

[0051] The second flow path 92 connects the discharge port 8b of the pump 8 and the inlet 9a of the cooler 9. The second flow path 92 supplies coolant O from the pump 8 to the cooler 9. The second flow path 92 extends axially from one side to the other. The second flow path 92 is provided in the gear peripheral wall portion 6f of the gear housing portion 82. The second flow path 92 extends across the space between the housing body 83 and the gear cover 85.

[0052] The third flow path 93 extends from the outlet 9b of the cooler 9 into the interior of the supply pipe 93A. The third flow path 93 has an in-wall flow path 93a that passes through the interior of the housing 6 and an in-pipe flow path 93b that passes through the interior of the supply pipe 93A.

[0053] The internal channel 93a extends axially from the outlet 9b of the cooler 9 to the other side (-Y side). The internal channel 93a opens into the internal space of the motor housing 81. A supply pipe 93A is inserted into and fixed at the opening of the internal channel 93a. The supply pipe 93A extends axially directly above the motor 2 inside the motor housing 81. In this specification, "directly above" means that the objects are positioned overlapping when viewed from above and in the vertical direction. Similarly, "directly below" means that the objects are positioned overlapping when viewed from below and in the vertical direction.

[0054] The internal flow path 93b extends axially inside the supply pipe 93A. The refrigerant O supplied to the internal flow path 93b flows axially above the motor 2. The supply pipe 93A is provided with injection holes that open towards the motor 2. The refrigerant O in the internal flow path 93b is injected into the stator 30 through the injection holes. In other words, the third flow path 93 extends into the motor housing 81 in the internal flow path 93b and supplies refrigerant O to the motor 2 from the outside.

[0055] The refrigerant O supplied to the motor 2 cools the stator 30 by absorbing heat from it as it travels along its surface. Furthermore, the refrigerant O drips from the stator 30 to the second refrigerant reservoir P2 and then returns to the first refrigerant reservoir P1 through the partition opening 6q.

[0056] According to this embodiment, by placing the motor 2 in the refrigerant path 90 and supplying refrigerant O to the motor 2, the motor 2 is cooled, preventing the motor 2 from overheating, and thus improving the reliability of the motor 2.

[0057] In this embodiment, the cooler 9 is fixed externally to the outer surface of the housing 6 in a region that overlaps radially with at least a portion of the gear housing 82, above the horizontal plane including the motor axis J2. This makes it easier to position the cooler 9 closer to the motor 2 and shorten the third flow path 93 connected to the cooler 9. As a result, it is possible to suppress the absorption of heat by the refrigerant O between the cooler 9 and the motor 2, and to keep the temperature of the refrigerant O supplied to the motor 2 low. Furthermore, according to this embodiment, by shortening the third flow path 93, it is possible to provide a drive unit 1 having an efficient refrigerant path 90 with suppressed pipeline resistance in the refrigerant path 90.

[0058] In particular, the cooler 9 in this embodiment is fixed to the gear peripheral wall portion 6f of the gear housing portion 82. This makes it easier to position the cooler 9 closer to the motor 2 compared to cases where the cooler 9 is fixed to the gear cover wall portion 6a of the gear housing portion 82. In addition, according to this embodiment, since the cooler 9 is positioned above the horizontal plane including the motor axis J2, it is easier to efficiently supply the coolant O flowing out from the outlet 9b of the cooler 9 to the motor 2 using gravity.

[0059] In this embodiment, the inlet 9a and outlet 9b of the cooler 9 are arranged side by side in the axial direction. Furthermore, the outlet 9b of the cooler 9 is positioned on the other axial side (-Y side) from the inlet 9a. As a result, the outlet 9b of the cooler 9 can be positioned closer to the motor 2, and the third flow path 93 can be made even shorter.

[0060] In this embodiment, the third flow path 93 passes through the inside of the supply pipe 93A and supplies refrigerant O to the motor 2 through the ejection port of the supply pipe 93A. Therefore, by utilizing the discharge pressure of the pump 8, the pressure inside the supply pipe 93A can be increased, allowing the refrigerant O to be dispersed far from the ejection port. This makes it easier for the refrigerant O to reach even the intricate parts of the motor 2, and allows the motor 2 to be cooled effectively. Alternatively, a trough-shaped catch tank may be placed directly above the motor 2 instead of the supply pipe 93A. In this case, the catch tank may be provided with a discharge port, and the refrigerant O stored in the catch tank may be supplied to the motor 2 by dripping it onto the motor 2.

[0061] In this embodiment, the refrigerant reservoir to which the first flow path 91 is connected is a first refrigerant reservoir P1 provided in the lower region of the housing 6. The pump 8, like the cooler 9, is fixed to the outer surface of the housing 6 in a region that overlaps radially with at least a part of the gear housing 82, above the horizontal plane including the motor axis J2. This allows the pump 8 and the cooler 9 to be placed close together, and the second flow path 92 connecting the pump 8 and the cooler 9 can be shortened. In particular, since the pump 8 in this embodiment is fixed to the gear peripheral wall portion 6f of the gear housing 82 together with the cooler 9, it is easier to further shorten the second flow path 92.

[0062] In this embodiment, the refrigerant reservoir to which the first flow path 91 is connected is a first refrigerant reservoir P1 provided in the lower region of the gear housing 82. However, the first flow path 91 may be a flow path connected to a second refrigerant reservoir P2 provided in the lower region of the motor housing 81. In other words, the first flow path 91 only needs to be connected to either the first refrigerant reservoir P1 or the second refrigerant reservoir P2, or both.

[0063] In this embodiment, it is preferable that at least a portion of the pump 8 and the cooler 9 overlap in the axial direction of the motor axis J2. Furthermore, the inlet 8a and outlet 8b of the pump 8, and the inlet 9a and outlet 9b of the cooler 9 are arranged in this order from one axial side (+Y side) to the other side (-Y side). As a result, the first flow path 91, the second flow path 92, and the third flow path 93 can be easily arranged in a straight line on the gear peripheral wall 6f, and the refrigerant path 90 can be simplified.

[0064] According to this embodiment, at least one of the first flow path 91 and the second flow path 92 is formed by a hole provided in the wall of the housing 6. That is, at least one of the first flow path 91 and the second flow path 92 is located inside the wall of the housing 6. Therefore, there is no need to provide a separate piping member between the first refrigerant reservoir P1 and the pump 8, and the number of parts can be reduced. However, the first flow path 91 and the second flow path 92 do not necessarily have to be located inside the wall of the housing 6, and a separate piping member may be provided.

[0065] Next, a modified example of the first embodiment will be described. As shown by dashed lines (two-dotted lines) in Figure 1, the refrigerant path 90 of the first embodiment can further adopt a modified configuration having a fifth flow path 95. In this modified configuration, the fifth flow path 95 is a path that supplies refrigerant O from the outlet 9b of the cooler 9 to the hollow portion 22 of the motor shaft 21.

[0066] The fifth flow path 95 is located inside the partition wall 6b along its wall surface. The fifth flow path 95 extends from the outlet 9b of the cooler 9 to the shaft passage hole 6p of the partition wall 6b. In this modified example, not only the fifth flow path 95 but also the third flow path 93 is connected to the outlet 9b of the cooler 9. Therefore, the third flow path 93 and the fifth flow path 95 share a portion of their upstream side. The fifth flow path 95 is a flow path that branches off from the path of the third flow path 93 inside the wall of the housing 6. When using a pump 8 with multiple discharge ports, the fifth flow path 95 may be directly connected to one of the discharge ports of the pump. In this case, the refrigerant path 90 branches inside the pump 8.

[0067] Figure 2 is a schematic cross-sectional view of the motor shaft 21 and partition wall 6b of this modified example. The motor shaft 21 has a hollow first hollow shaft 21A and a hollow second hollow shaft 21B. The first hollow shaft 21A is located inside the motor housing 81. The second hollow shaft 21B is located inside the gear housing 82.

[0068] The first hollow shaft 21A and the second hollow shaft 21B are positioned on the motor axis J2. That is, the first hollow shaft 21A and the second hollow shaft 21B are positioned coaxially. The first hollow shaft 21A and the second hollow shaft 21B are connected to each other at the connecting portion 21c. Therefore, the first hollow shaft 21A and the second hollow shaft 21B rotate synchronously around the motor axis J2.

[0069] The connecting portion 21c is located at one axial end (+Y side) of the first hollow shaft 21A. It is also located at the other axial end (-Y side) of the second hollow shaft 21B. The outer diameter of the other axial end (-Y side) of the second hollow shaft 21B is smaller than the inner diameter of the one axial end (+Y side) of the first hollow shaft 21A. The outer circumferential surface of the other axial end (-Y side) of the second hollow shaft 21B and the inner circumferential surface of the one axial end (+Y side) of the first hollow shaft 21A are provided with interlocking splines. The connecting portion 21c is constructed by inserting the other axial end (-Y side) of the second hollow shaft 21B into the one axial end (+Y side) of the first hollow shaft 21A.

[0070] At the connecting portion 21c, a small gap G is provided between the inner circumferential surface of the first hollow shaft 21A and the outer circumferential surface of the second hollow shaft 21B. The gap G extends from the hollow portion 22 of the motor shaft 21 to the outside of the motor shaft 21.

[0071] At least a portion of the connecting portion 21c is positioned inside the shaft passage hole 6p of the partition wall 6b. Between the inner surface of the shaft passage hole 6p and the motor shaft 21 are a pair of axially aligned sealing members 62 and 63 and a bearing 61 that rotatably supports the motor shaft 21. The bearing 61 supports the second hollow shaft 21B. The bearing 61 may also support the first hollow shaft 21A. Alternatively, two bearings may be positioned in the shaft passage hole 6p to support the first hollow shaft 21A and the second hollow shaft 21B, respectively.

[0072] The sealing members 62 and 63 seal the space between the inner circumferential surface of the shaft passage hole 6p and the outer circumferential surface of the motor shaft 21. In the axial direction, the gap G of the connecting portion 21c and the bearing 61 are located between the pair of sealing members 62 and 63. The downstream end of the fifth flow path 95 is open on the inner circumferential surface of the shaft passage hole 6p between the pair of sealing members 62 and 63.

[0073] Refrigerant O flows into the shaft passage hole 6p from the fifth passage 95. As described above, since sealing members 62 and 63 are provided on both axial sides of the opening of the fifth passage 95, the refrigerant O that flows into the shaft passage hole 6p accumulates inside the shaft passage hole 6p. In addition, the refrigerant O penetrates into the hollow portion 22 of the motor shaft 21 through the gap G between the first hollow shaft 21A and the second hollow shaft 21B.

[0074] In this modified example, the fifth flow path 95 extends from the outlet 9b of the cooler 9 to the connecting portion 21c and supplies refrigerant O to the hollow portion 22. The refrigerant O that enters the hollow portion 22 is supplied to the rotor 20 and stator 30, for example, through a hole provided in the first hollow shaft 21A, to cool the rotor 20 and stator 30 (see Figure 3, etc.). Alternatively, the refrigerant O that enters the hollow portion 22 may be supplied to the power transmission mechanism 3 through a hole provided in the second hollow shaft 21B.

[0075] In this modified example, the fifth flow path 95 allows the coolant O cooled by the cooler 9 to be supplied to the inside of the motor shaft 21. Furthermore, in this modified example, the fifth flow path 95 passes through the partition wall 6b. Therefore, the fifth flow path 95 can connect the cooler 9 and the hollow portion 22 of the motor shaft 21 over the shortest distance, and pressure loss in the fifth flow path 95 can be suppressed.

[0076] In this modified example, the bearing 61 is positioned between a pair of sealing members 62 and 63 in the axial direction. Therefore, a portion of the refrigerant O accumulated between the pair of sealing members 62 and 63 is supplied to the bearing 61. According to this modified example, when oil is used as the refrigerant O, the lubrication of the bearing 61 supporting the motor shaft 21 can be improved by the refrigerant O.

[0077] In this modified example, the case in which the connecting portion 21c is formed by inserting the end of the second hollow shaft 21B into the hollow portion of the end of the first hollow shaft 21A has been described. However, the connecting portion 21c may also have a configuration in which the end of the first hollow shaft 21A is inserted into the hollow portion of the end of the second hollow shaft 21B. In this case, interlocking splines are provided on the outer circumferential surface of the end of the first hollow shaft 21A and the inner circumferential surface of the end of the second hollow shaft 21B.

[0078] <Second Embodiment> Figure 3 is a schematic diagram of the drive unit 101 of the second embodiment. The drive unit 101 of this embodiment differs from the first embodiment mainly in the arrangement of the pump 8 and the configuration of the refrigerant path 190. In the descriptions of the embodiments and modified examples described below, components that are identical to those in the embodiments already described will be denoted by the same reference numerals, and their descriptions will be omitted.

[0079] Similar to the embodiments described above, the cooler 9 of this embodiment is fixed from the outside to the outer surface of the housing 6 in a region that overlaps radially with at least a portion of the gear housing 82, above the horizontal plane including the motor axis J2.

[0080] On the other hand, the pump 8 in this embodiment is located below the horizontal plane containing the motor axis J2. The pump 8 is fixed to the outer surface of the housing 6. More specifically, the pump 8 is fixed to the outer surface of the gear cover wall 6a.

[0081] The refrigerant path 190 in this embodiment includes a first passage 191, a second passage 192, a third passage 93, a fourth passage 194, a shaft passage 194c, and a rotor passage 194d. The entire length of the first passage 191, the second passage 192, and the fourth passage 194, as well as a portion of the third passage 93, are holes provided in the housing 6.

[0082] The first flow path 191 connects the first refrigerant reservoir P1 of the housing 6 to the suction port 8a of the pump 8. The refrigerant reservoir to which the first flow path 191 connects is the first refrigerant reservoir P1 located in the lower region of the gear housing 82. The first flow path 191 penetrates the gear cover wall 6a in the thickness direction.

[0083] According to this embodiment, since the pump 8 is located below the horizontal plane including the motor axis J2, the pump 8 can be positioned closer to the first refrigerant reservoir P1. This allows the first flow path 191 to be shortened.

[0084] The second flow path 192 connects the discharge port 8b of the pump 8 and the inlet 9a of the cooler 9. In the upstream region, the second flow path 192 is located inside the gear cover wall 6a along its surface. The gear cover wall 6a is a wall that covers one axial side (+Y side) of the power transmission mechanism 3. Therefore, the second flow path 192 extends vertically along one axial side (+Y side) of the power transmission mechanism 3. In the downstream region, the second flow path 192 extends axially between the housing body 83 and the gear cover 85.

[0085] The fourth passage 194 is a passage that branches off from the path of the second passage 192 inside the wall of the housing 6 (more specifically, inside the gear cover wall portion 6a). The fourth passage 194 connects the discharge port 8b of the pump 8 to one axial end (+Y side) of the shaft passage 194c. The fourth passage 194 is a passage that supplies the refrigerant O, which has been pumped to the pump 8, to the hollow portion 22 of the motor shaft 21.

[0086] The shaft internal passage 194c is a path that passes through the hollow section 22 of the motor shaft 21. In the shaft internal passage 194c, the refrigerant O flows along the axial direction. The hollow section 22 opens into the gear housing 82 at one end on the axial side (+Y side). The motor shaft 21 has a communication hole 194h that extends radially and connects the inside and outside of the hollow section 22. The radially outer opening of the communication hole 194h connects to the rotor internal passage 194d. Therefore, the communication hole 194h connects the shaft internal passage 194c and the rotor internal passage 194d.

[0087] The rotor internal passage 194d is a path through which the coolant O passes inside the rotor core 24 and is scattered to the stator 30. As the coolant O passes through the rotor internal passage 194d, it absorbs heat from the rotor 20, cooling the rotor 20. The coolant O passing through the shaft internal passage 194c is subjected to centrifugal force due to the rotation of the rotor 20. The coolant O passes radially outward through the rotor internal passage 194d and is scattered radially outward from the rotor 20, and is supplied to the stator 30 from the radially inside. As the coolant O supplied from the radially inside travels along the surface of the stator 30, it absorbs heat from the stator 30, cooling the stator 30 from the inside.

[0088] According to this embodiment, a portion of the refrigerant O stored in the first refrigerant reservoir P1 cools the motor 2 from the outside via the third flow path 93. Another portion of the refrigerant O stored in the first refrigerant reservoir P1 cools the motor 2 from the inside via the fourth flow path 194. In other words, according to this embodiment, the motor 2 can be cooled both inside and out using the refrigerant O, thereby increasing the cooling efficiency of the motor 2.

[0089] Figure 4 is a schematic diagram showing the configuration of the second channel 192 and the fourth channel 194 in this embodiment. On the other hand, Figure 5 is a schematic diagram showing the configuration of the second channel 192 and the fourth channel 194A in a modified example that can be adopted in this embodiment. In both the embodiment and its modified examples, the second channel 192 and the fourth channels 194 and 194A are arranged inside the gear cover wall 6a.

[0090] In this embodiment, as shown in Figure 4, the fourth channel 194 branches off from the second channel 192 at the branching section 192a. Therefore, the upstream regions of the second channel 192 and the fourth channel 194 are located within the same bore up to the branching section 192a. The downstream regions of the second channel 192 and the fourth channel 194 are located within separate bore sections extending from the branching section 192a.

[0091] In the modified example shown in Figure 5, the pump 8 has one inlet 8a and multiple outlets 8b, 108b. That is, in this modified example, the refrigerant path 190A branches inside the pump 8. In the refrigerant path 190A, the second flow path 192 is connected to one of the outlets 8b, and the fourth flow path 194 is connected to the other outlet 108b.

[0092] <Third Embodiment> Figure 6 is a schematic diagram of the drive unit 201 of the third embodiment. The drive unit 201 of this embodiment differs from the first embodiment mainly in the arrangement of the pump 8 and the configuration of the refrigerant path 290.

[0093] The cooler 9 is fixed from the outside to the outer surface of the housing 6 in a region that overlaps radially with at least a portion of the gear housing 82, above the horizontal plane containing the motor axis J2. In this embodiment, at least a portion of the cooler 9 also overlaps radially with the partition wall 6b.

[0094] On the other hand, the pump 8 in this embodiment is located below the horizontal plane containing the motor axis J2. Furthermore, the pump 8 is fixed to the outer surface of the housing 6. More specifically, the pump 8 is fixed to the outer surface of the motor peripheral wall portion 6g.

[0095] The hollow portion 22 of the motor shaft 21 opens into the gear housing 82 at one end on the axial side (+Y side) and into the motor housing 81 at the other end on the axial side (-Y side).

[0096] The refrigerant path 290 in this embodiment, similar to the embodiment described above, includes a first passage 291, a second passage 292, a third passage 93, a sixth passage 296, a tenth passage 270, a shaft passage 194c, and a rotor passage 194d. The entire length of the first passage 291, the second passage 292, the sixth passage 296, and the tenth passage 270, as well as a portion of the third passage 93, are holes provided in the housing 6.

[0097] The first flow path 291 connects the second refrigerant reservoir P2 of the housing 6 to the suction port 8a of the pump 8. The refrigerant reservoir to which the first flow path 291 connects is the second refrigerant reservoir P2, which is located in the lower region of the motor housing 81. The first flow path 291 penetrates the motor peripheral wall 6g in the thickness direction.

[0098] According to this embodiment, since the pump 8 is located below the horizontal plane including the motor axis J2, the pump 8 can be positioned closer to the second refrigerant reservoir P2. This allows the first flow path 291 to be shortened.

[0099] In this embodiment, the case in which the first flow path 291 is connected to the second refrigerant reservoir P2 has been described. However, as shown by the dashed line (two-dotted line) in Figure 6, the first flow path 291A may also be connected to the first refrigerant reservoir P1. That is, the refrigerant path 290 may have the modified first flow path 291A instead of the first flow path 291. Furthermore, the refrigerant path 290 may have a first flow path 291 connected to the first refrigerant reservoir P1 and a 291A connected to the second refrigerant reservoir P2. In this case, the pump 8 is connected to both the first flow paths 291 and 291A, or the two first flow paths 291 and 291A merge in the middle of the path.

[0100] The second flow path 292 connects the discharge port 8b of the pump 8 and the inlet 9a of the cooler 9. The second flow path 292 is located inside the partition wall 6b along its wall surface. Therefore, the second flow path 292 passes between the motor housing 81 and the gear housing 82.

[0101] In this embodiment, the cooler 9 overlaps radially with the partition wall 6b. Also, the inlet 9a of the cooler 9 overlaps radially with the partition wall 6b. Therefore, the second flow path 292 passing through the inside of the partition wall 6b can be connected to the inlet 9a of the cooler 9 without passing through a complex path. This simplifies the configuration of the refrigerant path 290 and suppresses the piping resistance of the refrigerant O.

[0102] The third flow path 93 extends from the outlet 9b of the cooler 9 into the interior of the supply pipe 93A. The third flow path 93 extends into the interior of the motor housing 81 and supplies refrigerant O to the motor 2 from the outside. The third flow path 93 is also connected to the tenth flow path 270 in the motor cover wall 6c of the housing 6.

[0103] The sixth passage 296 connects the outlet 9b of the cooler 9 to one axial end (+Y side) of the shaft passage 194c. The sixth passage 296 is located inside the gear peripheral wall 6f and the gear cover wall 6a of the housing 6. The sixth passage 296 is a passage that supplies the refrigerant O, which has been pumped to the pump 8, to the hollow section 22 of the motor shaft 21. The sixth passage 296 is a passage that branches off from the path of the third passage 93. If a pump with multiple discharge ports is used, the sixth passage 296 may be directly connected to one of the discharge ports of the pump 8. In this case, the refrigerant path 290 branches inside the pump 8.

[0104] The tenth flow path 270 connects the downstream end of the third flow path 93 to the other axial end of the shaft internal flow path 194c. The tenth flow path 270 is a flow path that supplies a portion of the refrigerant O that was not supplied to the motor 2 by the third flow path 93 to the hollow portion 22 of the motor shaft 21. The tenth flow path 270 is located inside the motor cover wall portion 6c of the housing 6.

[0105] The sixth passage 296 and the tenth passage 270 are connected to the shaft passage 194c. The refrigerant O that flows into the hollow section 22 from one axial side and the other side merges in the shaft passage 194c. The refrigerant O passing through the shaft passage 194c is subjected to centrifugal force due to the rotation of the rotor 20, passes radially outward through the rotor passage 194d, is scattered radially outward from the rotor 20, and is supplied to the stator 30. In this embodiment, a configuration may be adopted in which either or both of the sixth flow path 296 and the tenth flow path 270 are omitted. That is, in this embodiment, a configuration may be adopted in which no refrigerant O is supplied to the hollow portion 22, or a configuration may be adopted in which the refrigerant is supplied from only one or the other side in the axial direction.

[0106] In this embodiment, the refrigerant path 290 does not pass through the internal space of the gear housing 82. The refrigerant O accumulated in the first refrigerant reservoir P1 of the gear housing 82 is scraped up by the gears of the power transmission mechanism 3 and diffused to the tooth surfaces of each gear. According to this embodiment, the capacity of refrigerant O inside the gear housing 82 does not decrease, making it easier to ensure the lubrication of the power transmission mechanism 3.

[0107] <Fourth Embodiment> Figure 7 is a schematic diagram of the drive unit 301 of the fourth embodiment. The drive unit 301 of this embodiment differs from the first embodiment mainly in the configuration of the refrigerant path 390. Compared to the first embodiment, the refrigerant path 390 of this embodiment further includes a seventh flow path 397, an inverter flow path 397a, and a connecting flow path 397b.

[0108] The cooler 9 of this embodiment has one inlet 9a and multiple outlets 9b, 309b. That is, the refrigerant path 390 of this embodiment branches inside the cooler 9. A third flow path 93 is connected to one outlet 9b of the cooler 9, and a seventh flow path 397 is connected to the other outlet 309b.

[0109] The seventh passage 397 connects the outlet 309b of the cooler 9 to the inverter passage 397a. The seventh passage 397 is located inside the wall of the housing 6. More specifically, the seventh passage 397 extends from inside the wall of the gear housing 82 to inside the wall of the inverter housing 89. The seventh passage 397 supplies the coolant O cooled by the cooler 9 to the inverter 7.

[0110] The inverter flow path 397a cools the inverter 7 by passing through the inverter housing 89. The inverter flow path 397a passes, for example, through the boundary between the inverter housing 89 and the inverter 7. In this case, the refrigerant O comes into direct contact with the inverter 7 and cools it.

[0111] The connecting passage 397b connects the downstream end of the inverter passage 397a to the internal space of the gear housing 82. The connecting passage 397b is, for example, a passage located within piping connected to the housing 6. The connecting passage 397b may also be a passage located inside the wall of the housing 6. The connecting passage 397b is a path that returns the refrigerant O that has passed through the inverter passage 397a to the internal space of the gear housing 82. The downstream end of the connecting passage 397b preferably opens into the upper region within the gear housing 82. In this case, the refrigerant O flowing into the gear housing 82 from the downstream end of the connecting passage 397b is supplied to the tooth surfaces of the gears of the power transmission mechanism 3, thereby improving the lubrication of the power transmission mechanism 3.

[0112] <Fifth Embodiment> Figure 8 is a schematic diagram of the drive unit 401 of the fifth embodiment. The drive unit 401 of this embodiment has a configuration similar to that of the fourth embodiment, but mainly differs in the configuration of the refrigerant path 490. Compared to the refrigerant path 390 of the fourth embodiment (see Figure 7), the configuration of the seventh flow path 497 of the refrigerant path 490 of this embodiment differs. Furthermore, compared to the refrigerant path 390 of the fourth embodiment, the refrigerant path 490 of this embodiment has an additional sixth flow path 496. Moreover, compared to the refrigerant path 390 of the fourth embodiment, the refrigerant path 490 has an eleventh flow path 471, a shaft flow path 194c, and a rotor flow path 194d instead of the connecting flow path 397b.

[0113] In this embodiment, the hollow portion 22 of the motor shaft 21 opens into the gear housing 82 at one end on the axial side (+Y side) and into the motor housing 81 at the other end on the axial side (-Y side).

[0114] The cooler 9 of this embodiment has one inlet 9a and multiple outlets 9b, 409b. That is, the refrigerant path 490 of this embodiment branches inside the cooler 9. A third flow path 93 is connected to one outlet 9b of the cooler 9, and a sixth flow path 496 is connected to the other outlet 409b.

[0115] The sixth passage 496 connects the outlet 409b of the cooler 9 to the axial end (+Y side) of the shaft passage 194c. The sixth passage 496 is located inside the gear peripheral wall 6f and the gear cover wall 6a of the housing 6. The sixth passage 496 is a passage that supplies the refrigerant O, which has been pumped to the pump 8, to the hollow portion 22 of the motor shaft 21.

[0116] The seventh flow path 497 connects the outlet 409b of the cooler 9 to the inverter flow path 397a. The inverter flow path 397a cools the inverter 7 by passing through the inverter housing 89. The downstream end of the inverter flow path 397a is connected to the eleventh flow path 471. In this embodiment, the seventh flow path 497 is a flow path that branches off from the path of the third flow path 93.

[0117] The 11th passage 471 connects the downstream end of the inverter passage 397a to the other axial end of the shaft passage 194c. The 11th passage 471 is a passage that supplies the refrigerant O that has passed through the inverter passage 397a to the hollow portion 22 of the motor shaft 21. The 11th passage 471 is located inside the motor cover wall 6c of the housing 6.

[0118] The sixth passage 496 and the eleventh passage 471 are connected to the shaft passage 194c. The refrigerant O that flows into the hollow section 22 from one axial side and the other side merges in the shaft passage 194c. The refrigerant O passing through the shaft passage 194c is subjected to centrifugal force due to the rotation of the rotor 20, passes radially outward through the rotor passage 194d, is scattered radially outward from the rotor 20, and is supplied to the stator 30.

[0119] <Sixth Embodiment> Figure 9 is a schematic diagram of the drive unit 501 of the sixth embodiment. The drive unit 501 of this embodiment differs from the first embodiment mainly in the configuration of the refrigerant path 590. Compared to the first embodiment, the refrigerant path 590 of this embodiment further includes a ninth path 599, a tenth path 270, a shaft internal path 194c, a rotor internal path 194d, an inverter path 397a, and a connecting path 597a.

[0120] The ninth flow path 599 connects the downstream end of the third flow path 93 to the inverter flow path 397a. The ninth flow path 599 is a flow path that supplies a portion of the refrigerant O that was not supplied to the motor 2 in the third flow path 93 to the inverter flow path 397a. The ninth flow path 599 is located inside the wall of the housing 6. The inverter flow path 397a cools the inverter 7 by passing through the inverter housing 89.

[0121] The connecting channel 597a connects the downstream end of the inverter channel 397a to the internal space of the gear housing 82. The connecting channel 597a is, for example, a channel located within piping connected to the housing 6. The connecting channel 597a may also be a channel located inside the wall of the housing 6. The connecting channel 597a is a path that returns the refrigerant O that has passed through the inverter channel 397a to the internal space of the gear housing 82.

[0122] The 10th channel 270 connects the downstream end of the 3rd channel 93 to the other axial end of the shaft channel 194c. The 10th channel 270 is a channel that branches off from the path of the 9th channel 599.

[0123] A tenth passage 270 is connected to the shaft passage 194c. The refrigerant O passing through the shaft passage 194c is subjected to centrifugal force due to the rotation of the rotor 20, passes radially outward through the rotor passage 194d, is scattered radially outward from the rotor 20, and is supplied to the stator 30.

[0124] <Seventh Embodiment> Figure 10 is a schematic diagram of the drive unit 601 of the seventh embodiment. The drive unit 601 of this embodiment has a configuration similar to that of the fourth embodiment, but the configuration of the refrigerant path 690 is mainly different. Compared to the refrigerant path 390 of the fourth embodiment (see Figure 7), the refrigerant path 690 of this embodiment has an eighth passage 698, a shaft passage 194c, and a rotor passage 194d instead of the connecting passage 397b.

[0125] The eighth flow path 698 connects the downstream end of the inverter flow path 397a to the axial end (+Y side) of the shaft internal flow path. The eighth flow path 698 is, for example, a flow path located within piping connected to the housing 6. The eighth flow path 698 may also be a flow path located inside the wall of the housing 6. In this embodiment, the hollow portion 22 of the motor shaft 21 opens into the gear housing 82 at the axial end (+Y side). The eighth flow path 698 is a path that guides the refrigerant O that has passed through the inverter flow path 397a from the axial opening (+Y side) to the hollow portion 22.

[0126] An eighth passage 698 is connected to the shaft passage 194c. The refrigerant O passing through the shaft passage 194c is subjected to centrifugal force due to the rotation of the rotor 20, passes radially outward through the rotor passage 194d, is scattered radially outward from the rotor 20, and is supplied to the stator 30.

[0127] <Eighth Embodiment> Figure 11 is a schematic diagram of the drive unit 701 of the eighth embodiment. The drive unit 701 of this embodiment differs from the first embodiment mainly in the configuration of the refrigerant path 790.

[0128] In this embodiment, a catch tank (third refrigerant reservoir) P3 is provided inside the gear housing 82. The catch tank P3 opens upwards and stores refrigerant O. The catch tank P3 is located above the first refrigerant reservoir P1 and the second refrigerant reservoir P2. Furthermore, in this embodiment, the catch tank P3 stores refrigerant O above the motor axis J2. Here, storing refrigerant O above the motor axis J2 means that the lower end of the storage space where refrigerant O is stored is located above the motor axis J2.

[0129] The catch tank P3 is, for example, a trough-shaped member that protrudes from the inner surface of the gear housing 82. In this case, the catch tank P3 is part of the housing 6. Alternatively, the catch tank P3 may be a separate component from the housing 6. The catch tank P3 is connected to the inner surface of the gear housing 82. The catch tank P3 functions as a refrigerant reservoir. Therefore, the refrigerant reservoir provided inside the housing 6 includes a first refrigerant reservoir P1 provided in the lower region of the gear housing 82, a second refrigerant reservoir P2 provided in the lower region of the motor housing 81, and a third refrigerant reservoir (catch tank) P3 located above the first refrigerant reservoir P1 within the gear housing 82.

[0130] In this embodiment, the refrigerant path 790 includes a first flow path 791, a second flow path 92, and a third flow path 93, as well as a scraping path 791a.

[0131] The scraping path 791a is a path through which the refrigerant O is scraped up by the rotation of the gear (ring gear 51 in this embodiment) of the power transmission mechanism 3 and guided to the catch tank P3. In other words, in the refrigerant path 790 of this embodiment, the refrigerant O is supplied from the first refrigerant reservoir P1 to the catch tank P3 by the scraping action of the gear of the power transmission mechanism 3.

[0132] In this embodiment, the first flow path 791 connects the catch tank P3 and the suction port 8a of the pump 8. That is, in this embodiment, the refrigerant reservoir to which the first flow path 791 is connected is the catch tank P3.

[0133] In this embodiment, the pump 8 and cooler 9 are fixed to the outer surface of the housing 6 in a region that overlaps radially with at least a portion of the gear housing 82, above the horizontal plane including the motor axis J2. This allows the pump 8 and cooler 9 to be positioned closer together, and the second flow path 92 connecting the pump 8 and cooler 9 can be shortened. Furthermore, according to this embodiment, since the catch tank P3 is positioned above the first refrigerant reservoir P1, the first flow path 791 can be shortened. This suppresses the piping resistance of the refrigerant path 790.

[0134] Although various embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in each embodiment and modification are merely examples, and additions, omissions, substitutions, and other changes to the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by its embodiments. [Explanation of Symbols]

[0135] 1, 101, 201, 301, 401, 501, 601, 701… Drive unit, 2… Motor, 3… Power transmission mechanism, 6… Housing, 6a… Gear cover wall (cover wall), 6b… Partition, 7… Inverter, 8… Pump, 8a… Inlet, 8b, 108b… Outlet, 9… Cooler, 9a… Inlet, 9b, 309b, 409b… Outlet, 21… Motor shaft, 21c… Connecting part, 21A… First hollow shaft, 21B… Second hollow shaft, 22… Hollow part, 41… Gear, 81… Motor housing, 82… Gear housing, 89… Inverter housing, 90, 190, 190A, 290, 390, 490, 590, 690, 790…Refrigerant path, 91, 191, 291, 291A, 791…First path, 92, 192, 292…Second path, 93…Third path, 95…Fifth path, 194, 194A…Fourth path, 194c…Shaft internal path, 194h…Communication hole, 270…Tenth path, 296, 496…Sixth path, 397, 497…Seventh path, 397a…Inverter path, 471…Eleventh path, 599…Ninth path, 698…Eighth path, 791a…Scooping path, J2…Motor shaft, O…Refrigerant, P1…First refrigerant reservoir, P1…Refrigerant reservoir, P3…Catch tank (Third refrigerant reservoir)

Claims

1. A motor having a motor shaft that rotates around the motor axis, A power transmission mechanism connected to the motor shaft from one axial side, A housing having a motor housing section that houses the motor inside and a gear housing section that houses the power transmission mechanism inside, The refrigerant housed inside the housing, The refrigerant path through which the refrigerant circulates, A cooler for cooling the aforementioned refrigerant, The system comprises a pump for pressurizing the refrigerant, The aforementioned refrigerant path is A first flow path connecting the refrigerant reservoir in the housing and the suction port of the pump, A second flow path connecting the discharge port of the pump and the inlet of the cooler, It has a third flow path that extends from the outlet of the cooler into the motor housing and supplies the refrigerant to the motor, The cooler is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing, At least one of the first channel and the second channel is located inside the wall of the housing. The housing has a partition wall that separates the internal space of the motor housing from the internal space of the gear housing. The second flow path is arranged inside the partition wall along the wall surface of the partition wall, At least a portion of the cooler overlaps radially with the partition wall, Drive unit.

2. A motor having a motor shaft that rotates around the motor axis, A power transmission mechanism connected to the motor shaft from one axial side, A housing having a motor housing section that houses the motor inside and a gear housing section that houses the power transmission mechanism inside, The refrigerant housed inside the housing, The refrigerant path through which the refrigerant circulates, A cooler for cooling the aforementioned refrigerant, The system comprises a pump for pressurizing the refrigerant, The aforementioned refrigerant path is A first flow path connecting the refrigerant reservoir in the housing and the suction port of the pump, A second flow path connecting the discharge port of the pump and the inlet of the cooler, It has a third flow path that extends from the outlet of the cooler into the motor housing and supplies the refrigerant to the motor, The cooler is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing, The refrigerant reservoir is a first refrigerant reservoir provided in the lower region within the housing, The pump is located below the horizontal plane including the motor axis. Drive unit.

3. The housing has a cover wall portion that covers one axial side of the power transmission mechanism, The second flow path is arranged inside the cover wall along the wall surface of the cover wall, The drive device according to claim 2.

4. The aforementioned refrigerant reservoir is A first refrigerant reservoir is provided in the lower region of the gear housing, The gear housing includes a third refrigerant reservoir located above the first refrigerant reservoir, The refrigerant is supplied from the first refrigerant reservoir to the third refrigerant reservoir by the gears of the power transmission mechanism. The first flow path is connected to the third refrigerant reservoir. The pump is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing. The drive device according to claim 3.

5. A motor having a motor shaft that rotates around the motor axis, A power transmission mechanism connected to the motor shaft from one axial side, A housing having a motor housing section that houses the motor inside and a gear housing section that houses the power transmission mechanism inside, The refrigerant housed inside the housing, The refrigerant path through which the refrigerant circulates, A cooler for cooling the aforementioned refrigerant, The system comprises a pump for pressurizing the refrigerant, The aforementioned refrigerant path is A first flow path connecting the refrigerant reservoir in the housing and the suction port of the pump, A second flow path connecting the discharge port of the pump and the inlet of the cooler, It has a third flow path that extends from the outlet of the cooler into the motor housing and supplies the refrigerant to the motor, The cooler is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing, Equipped with an inverter, The housing has an inverter housing section for housing the inverter, The motor shaft is hollow, having a hollow portion extending in the axial direction. The aforementioned refrigerant path is An inverter flow path that passes through the inverter housing and cools the inverter, A ninth channel is provided, which connects the downstream end of the third channel to the inverter channel. Drive unit.

6. A motor having a motor shaft that rotates around the motor axis, A power transmission mechanism connected to the motor shaft from one axial side, A housing having a motor housing section that houses the motor inside and a gear housing section that houses the power transmission mechanism inside, The refrigerant housed inside the housing, The refrigerant path through which the refrigerant circulates, A cooler for cooling the aforementioned refrigerant, The system comprises a pump for pressurizing the refrigerant, The aforementioned refrigerant path is A first flow path connecting the refrigerant reservoir in the housing and the suction port of the pump, A second flow path connecting the discharge port of the pump and the inlet of the cooler, It has a third flow path that extends from the outlet of the cooler into the motor housing and supplies the refrigerant to the motor, The cooler is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing, The housing has a partition wall that separates the internal space of the motor housing from the internal space of the gear housing. The motor shaft has a first hollow shaft and a second hollow shaft that are arranged coaxially and connected to each other at a connecting portion. The refrigerant path has a fifth flow path that extends from the outlet of the cooler to the connecting portion and supplies the refrigerant into the inside of the motor shaft. The fifth channel is arranged inside the partition wall along the wall surface of the partition wall, Drive unit.

7. The fifth channel is a channel that branches off from the path of the third channel within the wall of the housing. The drive device according to claim 6.

8. At least one of the first channel and the second channel is located inside the wall of the housing. A drive device according to any one of claims 2 to 7.

9. The refrigerant reservoir is a first refrigerant reservoir provided in the lower region within the housing, The pump is fixed to the outer surface of the housing in a region above the horizontal plane including the motor axis and radially overlapping with at least a portion of the gear housing. The drive device according to claim 8.

10. The motor shaft is hollow, having a hollow portion extending in the axial direction. The aforementioned refrigerant path is The shaft internal flow path passing through the hollow portion of the motor shaft, The pump has a fourth flow path connecting the discharge port and the axial end of the flow path inside the shaft, A drive device according to any one of claims 1 to 9.

11. The fourth channel is a channel that branches off from the path of the second channel within the wall of the housing. The drive device according to claim 10.

12. The motor shaft has a communication hole that extends radially and connects the inside and outside of the hollow portion. The drive device according to claim 10 or 11.

13. The motor shaft is hollow, having a hollow section that opens into the gear housing at one end on the axial side and extends in the axial direction. The aforementioned refrigerant path is The shaft internal flow path passing through the hollow portion of the motor shaft, The cooler has a sixth flow path connecting the discharge port and the axial end of the flow path inside the shaft, A drive device according to any one of claims 1 to 12.

14. The sixth channel is a channel that branches off from the path of the third channel. The drive device according to claim 13.

15. The motor shaft is hollow, having a hollow section that opens into the motor housing at the other end on the axial side and extends in the axial direction. The aforementioned refrigerant path is The shaft internal flow path passing through the hollow portion of the motor shaft, A tenth channel is provided, which connects the downstream end of the third channel with the other axial end of the channel within the shaft. A drive device according to any one of claims 1 to 14.

16. Equipped with an inverter, The housing has an inverter housing section for housing the inverter, The aforementioned refrigerant path is An inverter flow path that passes through the inverter housing and cools the inverter, A seventh channel is provided that connects the outlet of the cooler and the inverter channel. A drive device according to any one of claims 1 to 15.

17. The seventh channel is a channel that branches off from the path of the third channel. The drive device according to claim 16.

18. The motor shaft is hollow, having a hollow section that opens into the gear housing at one end on the axial side and extends in the axial direction. The aforementioned refrigerant path is The shaft internal flow path passing through the hollow portion of the motor shaft, The system includes an eighth flow path connecting the downstream end of the inverter flow path and the axial end of the shaft internal flow path. The drive device according to claim 16 or 17.

19. The motor shaft is hollow, having a hollow section that opens into the motor housing at the other end on the axial side and extends in the axial direction. The aforementioned refrigerant path is The shaft internal flow path passing through the hollow portion of the motor shaft, A 11th channel is provided, which connects the downstream end of the inverter channel and the other axial end of the channel within the shaft. The drive device according to claim 16 or 17.

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