Drive unit

Abstract

To provide a drive unit capable of suppressing transfer of heat generated in a motor room to a heat storage portion.SOLUTION: A drive unit 10 includes a drive motor 20, a drive unit case 11 having a motor chamber 12 that houses the drive motor 20, an oil cooler 63 that cools a motor cooling oil R2 that cools the drive motor 20, and a storage portion 622 that stores the motor cooling oil R2. The drive unit case 11 is provided with a chain chamber 14 that is adjacent to the motor chamber 12 and is separate from the motor chamber 12 and partitioned from the motor chamber 12 by a first partition wall 114a. The storage portion 622 is provided at a position separated from the motor chamber 12 with the chain chamber 14 in between.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present invention relates to a drive unit mounted on an electric vehicle or the like. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have become more active, and research and development into electrification technologies is being conducted in vehicles to reduce CO2 emissions and improve energy efficiency.

[0003] In vehicle electrification technology, there is a demand for smaller drive units, particularly in terms of height, to increase the freedom of installation in vehicles. There is also a demand for more efficient power transmission to improve electricity consumption and driving range.

[0004] For example, Patent Document 1 describes a drive unit in which an oil reservoir that stores cooling oil for cooling the drive motor is provided below a motor chamber that houses the drive motor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-151112 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the drive unit described in Patent Document 1 has an oil reservoir located adjacent to the motor chamber, so heat generated in the motor chamber is transferred to the oil reservoir, causing the heat generated in the motor chamber to raise the temperature of the oil stored in the oil reservoir.

[0007] The present invention provides a drive unit capable of suppressing the transfer of heat generated in a motor chamber to a heat storage section. [Means for solving the problem]

[0008] The present invention relates to A drive motor; a drive unit case having a motor chamber for accommodating the drive motor; a heat exchanger for cooling a cooling liquid for cooling the drive motor; a reservoir for storing the cooling liquid; A drive unit comprising: a buffer chamber adjacent to the motor chamber and separated from the motor chamber by a partition wall is formed in the drive unit case; The storage section is provided at a position separated from the motor chamber across the buffer chamber. It is a drive unit. Effect of the Invention

[0009] According to the present invention, by isolating the reservoir from the motor chamber and sandwiching the buffer chamber between the reservoir and the motor chamber, it is possible to suppress the transfer of heat generated in the motor chamber to the reservoir. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a drive unit according to an embodiment of the present invention, viewed from the left side; [Diagram 2] FIG. 2 is a perspective view showing a drive unit according to an embodiment of the present invention with a part cut away. [Diagram 3] 3 is a partially cutaway perspective view for explaining a power transmission path in the drive unit of FIG. 2. FIG. [Figure 4] 3 is a skeleton diagram of a reduction gear in the drive unit of FIG. 2. [Diagram 5] 3A and 3B are a top view and a left side view of the drive unit of FIG. 2. [Figure 6] 3 is a perspective view of the left main case of the drive unit of FIG. 2, as viewed from the left. [Figure 7] 6 is a cross-sectional view taken along line AA in FIG. 5. [Figure 8] 3 is a perspective view of the left main case of the drive unit in FIG. 2, seen from the right. [Figure 9] 3 is a perspective view of the right main case of the drive unit in FIG. 2, seen from the left. [Figure 10] 6 is a cross-sectional view of FIG. 5 taken along line B-B. [Figure 11] FIG. 3 is a block diagram of a temperature adjustment system in the drive unit of FIG. 2. [Figure 12] 3 is a cross-sectional view of the drive unit of FIG. 2, cut in the left-right direction about the axis of the drive shaft, as viewed from the rear. [Figure 13] FIG. 13 is a cross-sectional perspective view of the separator and its vicinity in FIG. 12. [Figure 14] FIG. 13 is a cross-sectional perspective view of the vicinity of the oil discharge portion in FIG. 12. [Figure 15] 3 is a schematic diagram of the drive unit of FIG. 2 cut in the left-right direction so as to intersect with the storage section. FIG. [Figure 16] 3 is a perspective view showing the vicinity of the storage unit in FIG. 2 cut in the left-right direction. [Figure 17] 3 is a perspective view of the drive unit of FIG. 2, cut in part in the left-right direction. FIG. [Figure 18] 3 is a perspective view of the drive unit of FIG. 2, cut in part in the left-right direction. FIG. [Figure 19] FIG. 3 is a perspective view of a right main case of the drive unit of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A vehicle equipped with a drive unit according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The drawings are to be viewed in the direction of the reference symbols. In this specification and the like, for the sake of simplicity and clarity, the front / rear, left / right, and up / down directions are described according to the direction as seen by the driver of the vehicle, and in the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the top as U, and the bottom as D.

[0012] [Overall vehicle configuration] As shown in Fig. 1, a vehicle V of this embodiment has a pair of left and right front wheels FW, a pair of left and right rear wheels RW, and a floor panel FP that constitutes the floor of the vehicle V. The vehicle V is partitioned into a passenger compartment CB and a front room FRM in front of the passenger compartment CB by a dash panel DP that extends in the vertical direction above the floor panel FP. A front seat FS and a rear seat RS are provided in the passenger compartment CB.

[0013] The vehicle V includes a drive unit 10 serving as a drive source, a battery pack IPU that stores power to be supplied to the drive unit 10, a charging and supplying control device CHGR that controls the input and output power of the battery pack IPU, a power receiving unit PR that can receive power from an external power source, a radiator 611 through which coolant R1 flows to cool a control device 50 (described later) of the drive unit 10, and a coolant pump 612 that pumps the coolant R1. The coolant R1 is, for example, a coolant called LLC (Long Life Coolant).

[0014] The drive unit 10 is disposed behind the rear seat RS and below the floor panel FP. The battery pack IPU is disposed under the floor of the vehicle compartment CB below the floor panel FP. The battery pack IPU houses a plurality of battery modules, each of which has a plurality of stacked battery cells. Each battery cell is a chargeable and dischargeable secondary battery, such as a lithium-ion battery or an all-solid-state battery.

[0015] The charging control device CHGR is accommodated in the front room FRM. The power receiving unit PR is provided on the upper surface of the front room FRM and is electrically connected to the charging control device CHGR. The radiator 611 is accommodated in the front room FRM and disposed near the front end of the front room FRM. The radiator 611 is a heat exchanger that cools the coolant R1 by exchanging heat between the coolant R1 flowing through it and external air caused by wind generated when the vehicle V is traveling. The coolant pump 612 is accommodated in the front room FRM.

[0016] [Overall configuration of drive unit] 2 and 3, the drive unit 10 includes a drive motor 20, a reduction gear 30 that reduces the speed of the power output from the drive motor 20 and outputs it to the outside, a power transmission chain 40 that transmits the power output from the drive motor 20 to the reduction gear 30, a control device 50 that controls the drive motor 20, an oil pump 621 that pumps motor cooling oil R2, and an oil cooler 63 that exchanges heat between cooling water R1 and the motor cooling oil R2. The motor cooling oil R2 is, for example, an oil called ATF (Automatic Transmission Fluid).

[0017] In the drive unit 10, the drive motor 20, the reduction gear 30, the power transmission chain 40, and the control device 50 are housed in a drive unit case 11. The oil pump 621 and the oil cooler 63 are attached to the left side surface of the drive unit case 11.

[0018] The drive motor 20 is a so-called inner rotor type motor that includes a drive shaft 21, a rotor 22 that is attached to the drive shaft 21 and rotates integrally with the drive shaft 21, and a stator 23 that is arranged radially opposite the rotor 22 with a small gap between them on the radial outside of the rotor 22.

[0019] In this embodiment, in the drive unit 10, the drive motor 20 is arranged so that the axial direction (i.e., the drive shaft 21) faces horizontally in the left-right direction. By arranging the drive shaft 21 so that it faces horizontally in this manner, the vertical dimension of the drive unit 10 can be made compact.

[0020] The stator 23 includes a stator core 231 and a coil 232 attached to the stator core 231 and configured with a plurality of windings of U-phase, V-phase, and W-phase.

[0021] The stator core 231 is configured by laminating a plurality of thin electromagnetic steel sheets, each having a substantially annular shape, in the axial direction.

[0022] The stator core 231 includes a yoke portion 231a having a substantially circular ring shape forming an outer ring portion of the stator core 231 as viewed in the axial direction, and a plurality of teeth portions 231b protruding radially from the inner peripheral surface of the yoke portion 231a toward the center. The teeth portions 231b are arranged at equal intervals along the circumferential direction of the stator core 231 as viewed in the axial direction. A slot portion 231c is formed between the teeth portions 231b adjacent to each other in the circumferential direction of the stator core 231. A plurality of slot portions 231c are formed at equal intervals along the circumferential direction of the stator core 231. Each of the teeth portions 231b and the slot portions 231c extends along the axial direction of the stator core 231.

[0023] The coil 232 is composed of a plurality of conductor segments inserted into the slots 231c of the stator core 231. The conductor segments are inserted into all of the slots 231c formed in the circumferential direction of the stator core 231.

[0024] Coil 232 has a left coil end portion 232L that protrudes axially outward from the left end face on one axial side of stator core 231, and a right coil end portion 232R that protrudes axially outward from the right end face on the other axial side of stator core 231.

[0025] A drive sprocket 21a around which a power transmission chain 40 is wound is attached to the left end of the drive shaft 21. The drive sprocket 21a rotates together with the drive shaft 21.

[0026] As shown in FIGS. 3 and 4, the reduction gear 30 includes a planetary gear mechanism 31 and a differential gear mechanism 32.

[0027] First, the planetary gear mechanism 31 will be described.

[0028] The planetary gear mechanism 31 has an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinions 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0029] In this embodiment, the planetary gear mechanism 31 is arranged side by side in the front-rear direction behind the drive motor 20. The planetary gear mechanism 31 is arranged so that its axial direction (i.e., the input shaft 311) faces in the left-right direction parallel to the axial direction of the drive motor 20. The input shaft 311 of the planetary gear mechanism 31 is also arranged at a position at approximately the same height in the up-down direction as the drive shaft 21 of the drive motor 20. Furthermore, the outer diameter dimension of the planetary gear mechanism 31 is approximately the same as the outer diameter dimension of the drive motor 20, and the height of the drive unit 10 in the up-down direction is reduced.

[0030] The input shaft 311 is a hollow shaft, and a left drive shaft (described later) is inserted inside. A driven sprocket 311a around which the power transmission chain 40 is wound is attached to the left end of the input shaft 311. The driven sprocket 311a rotates integrally with the input shaft 311. The driven sprocket 311a has a larger diameter than the drive sprocket 21a attached to the drive shaft 21 of the drive motor 20, and the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a.

[0031] The sun gear 312 is an external gear provided on the input shaft 311 and rotates integrally with the input shaft 311 on the same rotation axis.

[0032] The multiple planetary pinion shafts 313 are arranged radially outside the sun gear 312 at equal intervals in the circumferential direction along the outer circumferential surface of the sun gear 312 so as to face in the left-right direction parallel to the input shaft 311. In this embodiment, the four planetary pinion shafts 313 are arranged radially outside the sun gear 312 at 90 degree intervals in the circumferential direction of the input shaft 311.

[0033] A stepped pinion 314 having a first planetary gear 314a and a second planetary gear 314b that rotate integrally is rotatably supported on each planetary pinion shaft 313. In this embodiment, the first planetary gear 314a is disposed on the left side and the second planetary gear 314b is disposed on the right side of each planetary pinion shaft 313. Therefore, four first planetary gears 314a and four second planetary gears 314b are provided in an annular shape at 90 degree intervals along the circumferential direction of the input shaft 311.

[0034] First planetary gear 314a is an external gear that is disposed on the outer circumferential surface of sun gear 312 and meshes with sun gear 312. The four first planetary gears 314a are provided in an annular shape at 90 degree intervals along the outer circumferential surface of sun gear 312. Each of the four first planetary gears 314a meshes with the outer circumferential surface of sun gear 312.

[0035] The second planetary gear 314b is an external gear disposed on the inner circumferential surface of the ring gear 317 and meshes with the ring gear 317. The four second planetary gears 314b are provided in an annular shape at 90 degree intervals along the inner circumferential surface of the ring gear 317. In this embodiment, the second planetary gears 314b are external gears having a smaller diameter than the first planetary gear 314a.

[0036] The planetary carrier 316 connects the four planetary pinion shafts 313. The planetary carrier 316 is integral with the four planetary pinion shafts 313 and is rotatable about a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0037] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b can rotate about the planetary pinion shaft 313 and can revolve together with the planetary pinion shaft 313 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312). The planetary carrier 316 rotates together with the orbital motion of the stepped pinion 314 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0038] The ring gear 317 is disposed so as to surround the four second planetary gears 314b disposed in a circular shape, and is an annular internal gear whose inner circumferential surface meshes with each of the second planetary gears 314b. In this embodiment, the ring gear 317 is fixed to the drive unit case 11, and the ring gear 317 itself does not rotate.

[0039] Next, the differential gear mechanism 32 will be described.

[0040] The differential gear mechanism 32 includes a differential case 321, a differential pinion shaft 322 supported by the differential case 321, a first bevel gear 323a and a second bevel gear 323b rotatably supported on the differential pinion shaft 322, a left side gear 324L and a right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b, and a left drive shaft 325L and a right drive shaft 325R.

[0041] The differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31. Therefore, the differential case 321 rotates integrally with the planetary carrier 316 of the planetary gear mechanism 31 on a rotation axis coaxial with the input shaft 311. The differential case 321 includes an accommodating portion 321a that accommodates the differential pinion shaft 322, the first bevel gear 323a, the second bevel gear 323b, the left side gear 324L, and the right side gear 324R.

[0042] Differential pinion shaft 322 is housed in housing portion 321a of differential case 321 and supported by differential case 321. Differential pinion shaft 322 is disposed in housing portion 321a of differential case 321 so as to be perpendicular to the rotation axis of differential case 321. Differential pinion shaft 322 rotates integrally with differential case 321 about the rotation axis of differential case 321.

[0043] The first bevel gear 323a is housed in a housing portion 321a of the differential case 321, and is rotatably supported by the differential pinion shaft 322. The first bevel gear 323a has a generally truncated cone shape with an upper surface facing the rotation axis of the differential case 321, and a gear is formed on the side surface of the truncated cone.

[0044] The second bevel gear 323b is housed in the housing portion 321a of the differential case 321 and is rotatably supported by the differential pinion shaft 322 so as to face the first bevel gear 323a. The second bevel gear 323b has a generally truncated cone shape with an upper surface facing the rotation axis of the differential case 321, and a gear is formed on the side surface of the truncated cone.

[0045] The left side gear 324L is accommodated in the accommodation portion 321a of the differential case 321, and is disposed on the left side of the differential pinion shaft 322 between the first bevel gear 323a and the second bevel gear 323b. The rotation axis of the left side gear 324L is coaxial with the rotation axis of the differential case 321. The left side gear 324L has a generally truncated cone shape with the upper surface facing the differential pinion shaft 322 (i.e., to the right), and a gear is formed on the side surface of the truncated cone. The left side gear 324L meshes with both the first bevel gear 323a and the second bevel gear 323b.

[0046] The right side gear 324R is accommodated in the accommodation portion 321a of the differential case 321, and is disposed between the first bevel gear 323a and the second bevel gear 323b on the right side of the differential pinion shaft 322, facing the left side gear 324L in the left-right direction with the differential pinion shaft 322 in between. The rotation axis of the right side gear 324R is coaxial with the rotation axis of the differential case 321 and the rotation axis of the left side gear 324L. The right side gear 324R has a substantially truncated cone shape with the upper surface facing the differential pinion shaft 322 (i.e., leftward), and a gear is formed on the side surface of the truncated cone. The right side gear 324R meshes with both the first bevel gear 323a and the second bevel gear 323b.

[0047] The left drive shaft 325L passes through the hollow portion of the input shaft 311 of the planetary gear mechanism 31 and the center of the driven sprocket 311a, and extends in the left-right direction coaxially with the rotation axis of the input shaft 311 of the planetary gear mechanism 31 and the rotation axis of the differential case 321. The left drive shaft 325L has a left side gear 324L attached to its right end, and a left rear wheel RW attached to its left end. Therefore, the left side gear 324L, the left drive shaft 325L, and the left rear wheel RW rotate together.

[0048] The right drive shaft 325R extends in the left-right direction coaxially with the rotation axis of the input shaft 311 of the planetary gear mechanism 31, the rotation axis of the differential case 321, and the rotation axis of the left drive shaft 325L. The right drive shaft 325R has a right side gear 324R attached to its left end and a right rear wheel RW attached to its right end. Therefore, the right side gear 324R, the right drive shaft 325R, and the right rear wheel RW rotate together.

[0049] In this way, by forming the differential case 321 integrally with the planetary carrier 316 of the planetary gear mechanism 31, the planetary gear mechanism 31 and the differential gear mechanism 32 can be formed into an integral structure, and the reduction gear 30 can be made more compact.

[0050] Next, a power transmission path of the power output from the drive motor 20 will be described.

[0051] Power generated by the drive motor 20 is output from the drive shaft 21, and the drive sprocket 21a attached to the drive shaft 21 rotates integrally with the drive shaft 21. When the drive sprocket 21a rotates, the driven sprocket 311a rotates due to the power transmission chain 40 wound around the drive sprocket 21a and the driven sprocket 311a attached to the input shaft 311 of the planetary gear mechanism 31. The input shaft 311 of the planetary gear mechanism 31 rotates integrally with the driven sprocket 311a. At this time, since the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a, the rotation of the drive shaft 21 is decelerated via the drive sprocket 21a, the power transmission chain 40, and the driven sprocket 311a, and is input to the input shaft 311 of the planetary gear mechanism 31.

[0052] In the planetary gear mechanism 31, power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. The stepped pinion 314 rotates and revolves around its axis. The planetary carrier 316 rotates integrally with the revolution of the stepped pinion 314. In the planetary gear mechanism 31, since the ring gear 317 is fixed, the rotation of the input shaft 311 is reduced in speed at a predetermined reduction ratio and transmitted to the planetary carrier 316.

[0053] In the differential gear mechanism 32, the differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31, and therefore rotates integrally with the rotation of the planetary carrier 316. Therefore, the power input to the input shaft 311 of the planetary gear mechanism 31 is reduced at a predetermined reduction ratio and input to the differential case 321 via the planetary carrier 316.

[0054] Therefore, the power output from the drive shaft 21 is input to the differential case 321 of the differential gear mechanism 32 via the power transmission chain 40 and the planetary gear mechanism 31, and the differential pinion shaft 322 revolves together with the differential case 321 around the rotation axis of the differential case 321.

[0055] When the vehicle V is moving straight, there is no difference in rotation between the left and right rear wheels RW, so the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate in response to the rotation of the differential pinion shaft 322. The left drive shaft 325L rotates together with the rotation of the left side gear 324L, causing the left rear wheel RW to rotate, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R, causing the right rear wheel RW to rotate.

[0056] When the vehicle V is turning, the differential pinion shaft 322 revolves and the first bevel gear 323a and the second bevel gear 323b rotate so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases, while the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate at different rotation speeds so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases. Then, the left drive shaft 325L rotates together with the rotation of the left side gear 324L to rotate the left rear wheel RW, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R to rotate the right rear wheel RW. Therefore, when the vehicle V is turning, the left drive shaft 325L and the right drive shaft 325R rotate so that the rotational speed of the rear wheel RW on the inside of the turn slows down and the rotational speed of the rear wheel RW on the outside of the turn increases.

[0057] In this manner, as shown by the arrows in FIG. 3, the power output from the drive motor 20 is decelerated via the drive sprocket 21a, the driven sprocket 311a, and the power transmission chain 40, and input to the reduction gear 30, where it is further decelerated by the planetary gear mechanism 31, and the power is appropriately distributed and transmitted to the left and right rear wheels RW by the differential gear mechanism 32.

[0058] Furthermore, by using the planetary gear mechanism 31 in the reduction mechanism, it is possible to obtain a desired reduction ratio while suppressing an increase in the radial dimension relative to the rotation axis direction.

[0059] Next, the drive unit case 11 will be described with reference to FIGS.

[0060] The drive unit case 11 has a main case 111, a left side cover 112 that covers the left side surface of the main case 111, and a right side cover 113 that covers the right side surface of the main case 111. The main case 111 is divided into two parts, a left main case 114 and a right main case 115.

[0061] The main case 111 is partitioned into a motor chamber 12 that houses the drive motor 20, a gear chamber 13 that houses the reduction gear 30, a chain chamber 14 that houses the power transmission chain 40, and a controller chamber 15 that houses the control device 50. The motor chamber 12 and the gear chamber 13 are formed side by side in the front-to-rear direction, with the motor chamber 12 at the front and the gear chamber 13 at the rear. The chain chamber 14 is formed on the left side of the motor chamber 12 and the gear chamber 13, and is open to the left. The controller chamber 15 is formed on the right side of the motor chamber 12 and the gear chamber 13, and is open to the right.

[0062] The left side cover 112 covers the left opening of the chain chamber 14. On the left side surface of the left side cover 112, an oil pump 621 and an oil cooler 63 are fixed.

[0063] 6 to 8, the left main case 114 forms the motor chamber 12, the gear chamber 13, and the chain chamber 14. The left main case 114 includes a first partition wall 114a that separates the motor chamber 12 from the chain chamber 14, and a second partition wall 114b that separates the motor chamber 12 from the gear chamber 13. The first partition wall 114a extends in the up-down direction and the front-rear direction between the drive sprocket 21a and the drive motor 20. The second partition wall 114b extends in the up-down direction and the left-right direction between the drive motor 20 and the reduction gear 30.

[0064] In the left main case 114, the motor chamber 12 is open to the right. In the left main case 114, the gear chamber 13 and the chain chamber 14 communicate with each other, but the left main case 114 is provided with a baffle plate 116 that separates the gear chamber 13 and the chain chamber 14 (see also FIG. 4). The baffle plate 116 extends in the up-down and front-rear directions between the driven sprocket 311a and the sun gear 312.

[0065] 9 and 10, the right main case 115 includes a right wall portion 123 covering the right opening of the motor chamber 12 formed in the left main case 114, and further includes a right wall portion 133 covering the right opening of the gear chamber 13 formed in the left main case 114, and a third partition wall 115a partitioning the motor chamber 12 and the gear chamber 13. The right main case 115 also forms a controller chamber 15 to the right of the right wall portion 123 including the front region of the right wall portion 133. In the right main case 115, the controller chamber 15 is open to the right.

[0066] The right side cover 113 covers the right opening of the controller chamber 15 .

[0067] (Temperature control system) 11, a temperature adjustment system 60 is configured in the vehicle V. The temperature adjustment system 60 includes a first temperature adjustment circuit 61 through which the above-mentioned cooling water R1 circulates and adjusts the temperature of the control device 50, a second temperature adjustment circuit 62 through which the above-mentioned motor cooling oil R2 circulates and adjusts the temperature and lubricates the drive motor 20, and the above-mentioned oil cooler 63. As described above, the oil cooler 63 exchanges heat between the cooling water R1 circulating in the first temperature adjustment circuit 61 and the motor cooling oil R2 circulating in the second temperature adjustment circuit 62.

[0068] In the first temperature control circuit 61, the cooling water R1 circulates through the cooling water pump 612, the control device 50, the oil cooler 63, and the radiator 611. The cooling water R1 pumped from the cooling water pump 612 is supplied to the control device 50 to control the temperature of the control device 50, is supplied from the control device 50 to the oil cooler 63, exchanges heat with the motor cooling oil R2 flowing in the second temperature control circuit 62, is supplied to the radiator 611, is cooled by heat exchange with the outside air, and returns to the cooling water pump 612.

[0069] In the second temperature control circuit 62, the motor cooling oil R2 circulates through the oil pump 621, the drive motor 20, and the oil cooler 63. A reservoir 622 is formed inside the drive unit case 11 to temporarily store the motor cooling oil R2 cooled by the oil cooler 63. The motor cooling oil R2 temporarily stored in the reservoir 622 is pumped from the oil pump 621 and supplied to the inside of the drive unit case 11 to control the temperature of the drive motor 20. The motor cooling oil R2 is supplied from the drive unit case 11 to the oil cooler 63 and cooled by heat exchange with the cooling water R1 flowing through the first temperature control circuit 61, and then flows into the reservoir 622 and is temporarily stored in the reservoir 622 again.

[0070] The gear chamber 13 and the chain chamber 14 separated by the baffle plate 116 store a common fluid, lubricating oil R3. The lubricating oil R3 is, for example, an oil called ATF (Automatic Transmission Fluid). The lubricating oil R3 has the same components as the motor cooling oil R2. The lubricating oil R3 lubricates the reduction gear 30 provided in the gear chamber 13, the drive sprocket 21a, the driven sprocket 311a, and the power transmission chain 40 provided in the chain chamber 14, etc. Note that although the mist-like motor cooling oil R2 of the second temperature control circuit 62 may be discharged from a breather hole 112b (described later) to the gear chamber 13, the lubricating oil R3 does not flow into the second temperature control circuit 62.

[0071] Next, the flow path of the motor cooling oil R2 in the motor chamber 12 in the second temperature adjustment circuit 62 of the temperature adjustment system 60 will be described with reference to FIGS.

[0072] 12, the left main case 114 forms a cylindrical outer peripheral wall portion 121 extending in the left-right direction of the motor chamber 12, and a left wall portion 122 of the motor chamber 12. The right main case 115 forms a right wall portion 123 of the motor chamber 12.

[0073] In the left main case 114, a cylindrical outer peripheral wall portion 121 covers the outer periphery of the drive motor 20. The left wall portion 122 extends radially inward from the outer peripheral wall portion 121 and covers the left side of the drive motor 20. In the right main case 115, the right wall portion 123 abuts against the right end portion of the outer peripheral wall portion 121 of the left main case 114 and covers the right side of the drive motor 20.

[0074] The left wall portion 122 includes an annular protruding wall portion 122a extending axially radially inside the left coil end portion 232L toward the axial center of the drive motor 20. The protruding wall portion 122a extends from the left wall portion 122 to a position where it axially overlaps with at least a portion of the left coil end portion 232L. An annular seal groove 122b is formed in the outer circumferential surface of the annular protruding wall portion 122a, and an annular O-ring 122c is provided in the seal groove 122b.

[0075] The right wall portion 123 includes an annular protruding wall portion 123a extending axially toward the axial center of the drive motor 20 radially inside the right coil end portion 232R. The protruding wall portion 123a extends from the right wall portion 123 to a position where it axially overlaps with at least a portion of the right coil end portion 232R. An annular seal groove 123b is formed on the outer circumferential surface of the annular protruding wall portion 123a, and an annular O-ring 123c is provided in the seal groove 123b.

[0076] A cylindrical seal wall member 124 is fitted to the outer circumferential surface of the annular protruding wall portion 123a. An O-ring 123c seals between the outer circumferential surface of the protruding wall portion 123a and the inner circumferential surface of the cylindrical seal wall member 124. The seal wall member 124 extends in the axial direction of the drive motor 20 to a position closer to the left end faces of the rotor 22 and the stator 23 of the drive motor 20 than the protruding wall portion 123a. An annular seal groove 124b is formed near the left end of the outer circumferential surface of the seal wall member 124, and an annular O-ring 124c is provided in the seal groove 124b.

[0077] In the driving motor 20, a seal cover 24 is provided in the radial gap between the rotor 22 and the stator 23, and extends cylindrically along the inner circumferential surface of the stator 23.

[0078] The left end of the seal cover 24 fits into the outer circumferential surface of the protruding wall portion 122a of the left wall portion 122. The gap between the outer circumferential surface of the protruding wall portion 122a and the inner circumferential surface of the left end of the seal cover 24 is sealed by an O-ring 122c.

[0079] The right end of the seal cover 24 is fitted into the outer circumferential surface of the seal wall member 124. The gap between the outer circumferential surface of the seal wall member 124 and the inner circumferential surface of the right end of the seal cover 24 is sealed by an O-ring 124c.

[0080] The space surrounded by the outer peripheral wall portion 121, the left wall portion 122, the protruding wall portion 122a, the seal cover 24, the seal wall member 124, the right wall portion 123, and the protruding wall portion 123a forms a motor chamber oil flow path 125 through which the motor cooling oil R2 flows. The motor chamber oil flow path 125 forms a sealed space within the motor chamber 12.

[0081] The motor chamber oil flow path 125 has a left annular flow path 125L that covers the left coil end portion 232L and is annular when viewed from the axial direction of the drive motor 20, a right annular flow path 125R that covers the right coil end portion 232R and is annular when viewed from the axial direction of the drive motor 20, and an axial flow path 125A that is formed radially outside the seal cover 24 by the slot portion 231c of the stator 23.

[0082] In this embodiment, an oil introduction section 126 through which the motor cooling oil R2 is introduced into the motor chamber oil flow passage 125 is provided at the bottom of the right annular flow passage 125R. The oil introduction section 126 is provided so as to face outward in the axial direction from the right wall section 123 at the bottom of the right annular flow passage 125R. In addition, an oil discharge section 127 through which the motor cooling oil R2 that has flowed through the motor chamber oil flow passage 125 is discharged is provided at the top of the left annular flow passage 125L. The oil discharge section 127 is provided so as to face outward in the axial direction from the left wall section 122 at the top of the left annular flow passage 125L.

[0083] The motor cooling oil R2 pumped from the oil pump 621 is introduced into the oil introduction portion 126 (see FIG. 15).

[0084] The motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow passage 125 flows from right to left through the axial flow passage 125A while flowing through the right annular flow passage 125R. The motor cooling oil R2 that has flowed from right to left through the axial flow passage 125A flows into the left annular flow passage 125L, and the motor chamber oil flow passage 125 becomes filled with the motor cooling oil R2.

[0085] When the motor chamber oil passage 125 is filled with the motor cooling oil R2, the stator 23 is immersed in the motor cooling oil R2 filled in the motor chamber oil passage 125, and is cooled by the motor cooling oil R2.

[0086] The motor cooling oil R2 stored in the motor chamber oil flow path 125 is discharged from the oil discharge portion 127 according to the flow rate of the motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow path 125.

[0087] In this manner, the motor cooling oil R2 filling the motor chamber oil passage 125 is circulated, and the stator 23 is cooled by being immersed in the motor cooling oil R2 filling the motor chamber oil passage 125.

[0088] At this time, since the motor chamber oil flow path 125 is a sealed space within the motor chamber 12, the motor cooling oil R2 flowing through the axial flow path 125A does not come into contact with the rotor 22 due to the seal cover 24. Furthermore, the gap between the seal cover 24 and the outer circumferential surface of the rotor 22 is not filled with the motor cooling oil R2, and instead is an air layer.

[0089] Since air has a lower viscous resistance than the motor cooling oil R2, the presence of a layer of air between the outer peripheral surface of the rotor 22 and the inner peripheral surface of the stator 23 reduces energy loss when the drive motor 20 is driven to rotate the rotor 22.

[0090] 12 to 14, a separator 128 is provided in an upper portion of the left annular flow passage 125L between the oil discharge portion 127 and the stator 23 in the axial direction of the drive motor 20, at a position overlapping with the oil discharge portion 127 as viewed from the axial direction of the drive motor 20. The separator 128 extends in the vertical direction, and divides the upper portion of the left annular flow passage 125L into a left space (the oil discharge portion 127 side) and a right space (the drive motor 20 side) in the axial direction of the drive motor 20.

[0091] Between an upper end portion 128a of the separator 128 and the main case 111 of the drive unit case 11, a communication space 125c is formed.

[0092] Therefore, the motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow passage 125 is stored in the space on the right side (the drive motor 20 side) at the upper part inside the left annular flow passage 125L.

[0093] Then, when the liquid level of the motor cooling oil R2 stored in the space on the right side of the separator 128 (the side of the drive motor 20) at the top of the left annular flow path 125L exceeds the upper end 128a of the separator 128, the motor cooling oil R2 flows from the communicating space 125c into the space on the left side of the separator 128 (the side of the oil discharge section 127) and is discharged from the oil discharge section 127 to the outside of the motor chamber oil flow path 125.

[0094] The separator 128 extends in the vertical direction such that an upper end portion 128a is located higher than an upper end of the coil 232 of the drive motor 20. In other words, the separator 128 extends in the vertical direction such that a lower end portion of a communication space 125c formed between the upper end portion 128a of the separator 128 and the main case 111 of the drive unit case 11 is located higher than an upper end of the coil 232 of the drive motor 20.

[0095] Therefore, in the motor chamber oil flow path 125, the motor cooling oil R2 fills up to a position higher than the upper end of the coil 232, regardless of the position of the oil discharge part 127. As a result, even if the oil discharge part 127 is provided at a low position in the motor chamber oil flow path 125, the entire coil 232 can be reliably immersed in the motor cooling oil R2 and cooled, so that the oil discharge part 127 can be provided in the left wall part 122 of the motor chamber 12 without reducing the cooling efficiency of the coil 232, and the vertical dimension of the drive unit 10 can be made compact.

[0096] Furthermore, the oil discharge portion 127 is provided so that at least a portion of it is located lower than the upper end portion 128a of the separator 128 in the vertical direction.

[0097] This allows the motor cooling oil R2 that has flowed over the upper end 128a of the separator 128 and from the communication space 125c into the space on the left side of the separator 128 (the oil discharge portion 127 side) to be discharged outside the motor chamber oil flow path 125 more efficiently.

[0098] Furthermore, the oil discharge portion 127 is provided on the left wall portion 122 of the motor chamber 12, whereas the oil introduction portion 126 is provided on the right wall portion 123 of the motor chamber 12. Therefore, the motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow path 125 reliably flows in the axial direction from the right side to the left side of the drive motor 20. This ensures that the motor chamber oil flow path 125 is filled with the motor cooling oil R2, so that the entire coil 232 can be reliably immersed in the motor cooling oil R2 and cooled.

[0099] Furthermore, the oil discharge portion 127 is provided at the top of the motor chamber 12, whereas the oil introduction portion 126 is provided at the bottom of the motor chamber 12. In this manner, by providing the oil introduction portion 126 at a lower position than the oil discharge portion 127, the motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow path 125 reliably flows in the vertical direction from the lower side to the upper side of the drive motor 20. This ensures that the motor chamber oil flow path 125 is filled with the motor cooling oil R2, so that the entire coil 232 can be reliably immersed in the motor cooling oil R2 and cooled.

[0100] As shown in Figures 14 to 17, the motor cooling oil R2 discharged from the oil discharge section 127 is supplied to the oil cooler 63 through an oil cooler connection pipe 623 provided in the drive unit case 11 and connecting the oil discharge section 127 of the motor chamber 12 to the oil cooler 63.

[0101] In this embodiment, the chain chamber 14 is provided adjacent to the left side of the motor chamber 12, and the storage portion 622 is provided adjacent to the left side of the chain chamber 14. Furthermore, the oil cooler 63 is provided adjacent to the left side of the storage portion 622.

[0102] The left side cover 112 is provided with a partition wall 112a that separates the chain chamber 14 and the storage portion 622. Therefore, the chain chamber 14 and the storage portion 622 are separated by the partition wall 112a.

[0103] Storing portion 622 is formed in left side cover 112 so as to be open on the left side. Drive unit case 11 further includes a storage portion cover 117 that closes the left side of storing portion 622. Storage portion cover 117 is attached to the left side of left side cover 112. The left side of storing portion 622 is closed by storage portion cover 117.

[0104] Therefore, the storage section 622 is provided adjacent to the chain chamber 14 and at a position separated from the motor chamber 12 with the chain chamber 14 in between.

[0105] As a result, by isolating the storage section 622 from the motor chamber 12, which is a heat source, and sandwiching the chain chamber 14 between the storage section 622 and the motor chamber 12, the heat generated in the motor chamber 12 can be prevented from being transferred to the storage section 622, and the motor cooling oil R2 stored in the storage section 622 can be maintained at a low temperature.

[0106] The oil cooler 63 is attached to the left side surface of the reservoir cover 117 .

[0107] In this way, the motor cooling oil R2 discharged from the oil discharge portion 127 of the motor chamber 12 is supplied to the oil cooler 63 through the oil cooler connection pipe 623. This makes it possible to supply the motor cooling oil R2 discharged from the oil discharge portion 127 to the oil cooler 63 separated from the motor chamber 12 with a simple configuration.

[0108] The reservoir cover 117 is formed with a through hole 117a into which the motor cooling oil R2 discharged from the oil cooler 63 flows.

[0109] The motor cooling oil R2 cooled in the oil cooler 63 by heat exchange with the cooling water R1 circulating through the first temperature adjustment circuit 61 flows into the reservoir 622 through the through hole 117a and is stored in the reservoir 622.

[0110] This makes it possible to form a flow passage that connects oil cooler 63 and reservoir 622 with a simple configuration.

[0111] An oil pump 621 that pumps out the motor cooling oil R2 is attached to the left side surface of the left side cover 112 (see FIG. 2). The oil pump 621 is connected to the oil introduction portion 126 of the motor chamber 12 via an oil supply passage 624 formed in the drive unit case 11.

[0112] Then, the oil pump 621 pumps out the motor cooling oil R2 temporarily stored in the storage section 622, and supplies it to the motor chamber oil flow path 125 formed inside the motor chamber 12 via the oil supply flow path 624.

[0113] In this way, by introducing the motor cooling oil R2 stored in the reservoir 622 located at a position away from the motor chamber 12, which is the heat source, into the motor chamber 12 from the oil inlet 126 of the motor chamber 12 by the oil pump 621, it is possible to supply lower temperature motor cooling oil R2 to the motor chamber 12, thereby improving the cooling efficiency of the drive motor 20.

[0114] In addition, when viewed from the direction of the rotation axis of the drive motor 20, the oil cooler connection pipe 623, through which the heated R2 that has cooled the drive motor 20 flows, is formed in front of the rotation axis of the drive motor 20, whereas the oil supply passage 624, through which the motor cooling oil R2 cooled by the oil cooler 63 flows, is formed behind the rotation axis of the drive motor 20.

[0115] In this way, when viewed from the direction of the rotational axis of the drive motor 20, the oil cooler connecting pipe 623 and the oil supply passage 624 are provided at a distance from each other on one side and the other side opposite each other across the drive motor 20, so that the motor cooling oil R2 flowing through the oil supply passage 624 can be prevented from being heated by the motor cooling oil R2 flowing through the oil cooler connecting pipe 623.

[0116] A breather hole 112b that connects the chain chamber 14 and the storage portion 622 is provided in the partition wall 112a at a position that is to be the upper part of the storage portion 622.

[0117] When the pressure in the reservoir 622 exceeds a predetermined pressure, gas containing mist-like motor cooling oil R2 is released from the breather hole 112b into the chain chamber 14, and the pressure in the reservoir 622 is maintained at or below the predetermined pressure.

[0118] In this way, since the lubricating oil R3 is an oil with the same components as the motor cooling oil R2, the pressure in the storage section 622 can be maintained below a predetermined pressure using the breather paths of the chain chamber 14 and the gear chamber 13. Therefore, the breather path of the motor cooling oil R2 stored in the storage section 622 can be shared with the breather path of the lubricating oil R3 that lubricates the reduction gear 30 and the power transmission chain 40, and the drive unit 10 can be made smaller.

[0119] As mentioned above, although the mist-like motor cooling oil R2 from the second temperature control circuit 62 may be released into the gear chamber 13 from the breather hole 112b, the lubricating oil R3 is prevented from flowing into the second temperature control circuit 62.

[0120] As a result, the lubricating oil R3 does not mix with the motor cooling oil R2, so that the lubricating oil R3, which is likely to contain a large amount of sludge, can be prevented from being supplied to the drive motor 20.

[0121] (Gear and chain chamber lubrication and cooling)

[0122] 17 to 19, in the chain chamber 14, the lower part of the driven sprocket 311a is immersed in the lubricating oil R3 stored in the lower part of the chain chamber 14. The driven sprocket 311a scoops up the lubricating oil R3 stored in the lower part of the chain chamber 14, and the drive sprocket 21a, the driven sprocket 311a, the power transmission chain 40, and the like provided in the chain chamber 14 are lubricated and cooled by the lubricating oil R3 scooped up by the driven sprocket 311a.

[0123] Therefore, the higher the level of the lubricating oil R3 in the chain chamber 14, the more efficiently the driven sprocket 311a scoops it up.

[0124] In the gear chamber 13, the lubricating oil R3 scooped up by the driven sprocket 311a in the chain chamber 14 passes through the inside of the hollow input shaft 311 and is supplied from the hollow input shaft 311 to the gear chamber 13. The lubricating oil R3 supplied from the chain chamber 14 lubricates and cools the reduction gear 30.

[0125] Therefore, by increasing the amount of lubricating oil R3 discharged from the hollow input shaft 311, it is possible to sufficiently lubricate and cool the reduction gear 30 even if the liquid level of the lubricating oil R3 in the gear chamber 13 is lowered. Therefore, by increasing the amount of lubricating oil R3 discharged from the hollow input shaft 311 and lowering the liquid level of the lubricating oil R3 in the gear chamber 13, the agitation resistance that agitates the lubricating oil R3 due to the rotation of the reduction gear 30 becomes smaller, and loss during rotation of the reduction gear 30 decreases.

[0126] In this way, it is desirable that the liquid level of the lubricating oil R3 in the chain chamber 14 be high, and that the liquid level of the lubricating oil R3 in the gear chamber 13 be low.

[0127] The gear chamber 13 is formed with an accommodation chamber 130 in which the planetary gear mechanism 31 and the differential gear mechanism 32 are accommodated. The accommodation chamber 130 has a substantially circular cross section as viewed from the direction of the rotation axis of the planetary gear mechanism 31 and the differential gear mechanism 32. A part of the lubricating oil R3 supplied from the chain chamber 14 to the gear chamber 13 through the inside of the input shaft 311 is stored in the lower part of the accommodation chamber 130. The lower part of the planetary gear mechanism 31 and the lower part of the differential gear mechanism 32 are immersed in the lubricating oil R3 stored in the lower part of the accommodation chamber 130. The lubricating oil R3 stored in the lower part of the accommodation chamber 130 is scooped up by the rotation of the planetary gear mechanism 31 and the differential gear mechanism 32, and the lubricating oil R3 scooped up by the rotation of the planetary gear mechanism 31 and the differential gear mechanism 32 also lubricates and cools the planetary gear mechanism 31 and the differential gear mechanism 32.

[0128] In this embodiment, as described above, the gear chamber 13 and the chain chamber 14 communicate with each other in the left main case 114, but the left main case 114 is provided with a baffle plate 116 that separates the gear chamber 13 and the chain chamber 14. The baffle plate 116 extends between the driven sprocket 311a and the sun gear 312 in the up-down and front-rear directions.

[0129] The baffle plate 116 extends upward from the bottom of the chain chamber 14 and the gear chamber 13, and restricts the movement of the lubricating oil R3 between the chain chamber 14 and the gear chamber 13.

[0130] This allows the liquid level of the lubricating oil R3 in the chain chamber 14 to be different from the liquid level of the lubricating oil R3 in the gear chamber 13, making it possible to increase the liquid level of the lubricating oil R3 in the chain chamber 14 and decrease the liquid level of the lubricating oil R3 in the gear chamber 13. Therefore, the stirring resistance of the lubricating oil R3 caused by the rotation of the reduction gear 30 can be reduced while improving the lubricating performance in the gear chamber 13 and the chain chamber 14.

[0131] An upper space 131 is formed above the gear chamber 13. The upper space 131 is formed between the motor chamber 12 and the accommodation chamber 130 of the gear chamber 13. The upper space 131 is formed within the accommodation chamber 130 and communicates with the accommodation chamber 130. The upper space 131 is formed in the second partition wall 114b.

[0132] A lower space 132 is formed in the lower part of the gear chamber 13. The lower space 132 is partitioned as a separate room from the accommodation chamber .

[0133] The lower space 132 is formed below the upper space 131. The lower space 132 is formed between the motor chamber 12 and the accommodation chamber 130 of the gear chamber 13. The upper space 131 and the lower space 132 are separated by an upper and lower partition wall 114c extending rearward from the second partition wall 114b.

[0134] The upper space 131 and the lower space 132 are formed between the motor chamber 12 and the accommodation chamber 130 of the gear chamber 13, and both of them store the lubricating oil R3.

[0135] This makes it possible to provide the upper space 131 and the lower space 132 while preventing the vertical dimension of the drive unit case 11 from becoming large. By storing the lubricating oil R3 in the upper space 131 and the lower space 132, the liquid level of the lubricating oil R3 stored in the lower part of the accommodation chamber 130 can be lowered, so that the stirring resistance of the lubricating oil R3 caused by the rotation of the reduction gear 30 can be further reduced.

[0136] The upper space 131 extends in the axial direction of the output rotating shaft of the reduction gear 30, and is partitioned in the axial direction of the output rotating shaft of the reduction gear 30 into a planetary side upper storage portion 131a and a differential side upper storage portion 131b.

[0137] In this way, by forming the upper space 131 so as to be long in the axial direction of the output rotating shaft of the reduction gear transmission 30 and dividing it into a plurality of spaces in the axial direction of the output rotating shaft of the reduction gear transmission 30, it is possible to lengthen the time that the lubricating oil R3 stays in the upper space 131. This makes it possible to suppress foaming of the lubricating oil R3 and to lower the temperature of the lubricating oil R3.

[0138] Moreover, the upper space 131, that is, the planetary side upper storage portion 131a and the differential side upper storage portion 131b are integrally formed by casting in the drive unit case 11 (in this embodiment, the left main case 114).

[0139] In the planetary-side upper reservoir 131a, a portion of the lubricating oil R3 that is scooped up and scattered from the lower part of the accommodation chamber 130 by the planetary gear mechanism 31 is collected and stored.

[0140] In addition, a portion of the lubricating oil R3 discharged from the input shaft 311 radially outward and scattered is collected and stored in the planetary-side upper storage portion 131a.

[0141] As a result, the lubricating oil R3 discharged radially outward from the input shaft 311 and scattered, and the lubricating oil R3 scooped up and scattered by the planetary gear mechanism 31 are collected in the planetary-side upper reservoir 131a, thereby making it possible to lower the liquid level of the lubricating oil R3 stored in the lower part of the accommodation chamber 130, thereby making it possible to reduce the stirring resistance of the lubricating oil R3 caused by the rotation of the reduction gear 30. In this way, the height dimension of the drive unit 10 can be reduced without reducing the power transmission efficiency.

[0142] In the differential-side upper reservoir 131b, a portion of the lubricating oil R3 that is scooped up and scattered from the lubricating oil R3 stored in the lower part of the gear chamber 13 by the differential gear mechanism 32 including the differential case 321 is collected and stored.

[0143] In addition, the differential-side upper reservoir 131b collects and stores a portion of the lubricating oil R3 that is discharged from the right end of the input shaft 311 toward the differential gear mechanism 32 and scattered by the rotation of the differential gear mechanism 32.

[0144] As a result, the lubricating oil R3 discharged from the right end of the input shaft 311 toward the differential gear mechanism 32 and scattered by the rotation of the differential gear mechanism 32, and the lubricating oil R3 scooped up from the bottom of the storage chamber 130 by the differential gear mechanism 32 including the differential case 321 and scattered, are collected in the differential side upper storage section 131b. This makes it possible to lower the liquid level of the lubricating oil R3 stored in the bottom of the storage chamber 130, and thereby reduce the stirring resistance of the lubricating oil R3 caused by the rotation of the reduction gear device 30.

[0145] In the left main case 114, the planetary side upper storage portion 131a and the differential side upper storage portion 131b are adjacent to each other in the rotational axis direction of the planetary gear mechanism 31 and the differential gear mechanism 32, with an upper partition wall 114d in between. The upper partition wall 114d is provided with a first oil circulation hole 134a that communicates between the planetary side upper storage portion 131a and the differential side upper storage portion 131b and through which the lubricating oil R3 flows.

[0146] This allows the lubricating oil R3 stored in the planetary-side upper reservoir 131a to flow into the differential-side upper reservoir 131b.

[0147] The left main case 114 and the right main case 115 are assembled with a gasket 136 sandwiched therebetween. The gasket 136 is a plate-shaped member extending in the up-down and front-rear directions. The differential-side upper storage portion 131b is formed on the left side of the gasket 136, and the wall portion of the differential-side upper storage portion 131b is formed by the left main case 114 and the gasket 136. The gasket 136 forms at least a part of the right wall of the differential-side upper storage portion 131b. A breather chamber 137 is formed on the right side of the gasket 136 adjacent to the differential-side upper storage portion 131b with the gasket 136 sandwiched therebetween, and the wall portion of the breather chamber 137 is formed by the right main case 115 and the gasket 136. The gasket 136 forms at least a part of the left wall of the breather chamber 137.

[0148] This makes it possible to form the wall of the differential-side upper reservoir 131b and the breather chamber 137 at low cost and while suppressing an increase in weight.

[0149] The gasket 136 is provided with a communication hole 136a that communicates between the differential side upper reservoir 131b and the breather chamber 137 and through which the gas in the differential side upper reservoir 131b and the breather chamber 137 and the mist of the lubricating oil R3 flow.

[0150] This makes it possible to easily form the communication hole 136a that communicates between the differential-side upper reservoir 131b and the breather chamber 137.

[0151] Further, a breather hole 137a communicating with the outside of the drive unit case 11 is provided at the upper part of the breather chamber 137. When the pressure in the gear chamber 13 exceeds a predetermined pressure, gas is released from the breather hole 137a, and the pressure in the gear chamber 13 is maintained at or below the predetermined pressure.

[0152] Furthermore, the upper space 131 communicates with the chain chamber 14. For example, the upper space 131 may communicate with the chain chamber 14 by not having the baffle plate 116 above the upper space 131. Furthermore, for example, although the upper space 131 is separated from the chain chamber 14 by the baffle plate 116, a communication hole that communicates between the upper space 131 and the chain chamber 14 may be provided in the baffle plate 116.

[0153] Therefore, when the pressure in the chain chamber 14 increases, the gas in the chain chamber 14, including the mist of lubricating oil R3, flows into the upper space 131. Then, together with the gas in the gear chamber 13, including the mist of lubricating oil R3, it flows through the upper space 131 to the breather chamber 137. When the pressure in the gear chamber 13 exceeds a predetermined pressure, the gas is released from the breather hole 137a. As a result, the pressure in the chain chamber 14 as well as the gear chamber 13 is maintained below the predetermined pressure.

[0154] Furthermore, when the pressure in the reservoir 622 exceeds a predetermined pressure, the gas containing the mist of motor cooling oil R2 discharged from the breather hole 112b to the chain chamber 14 flows from the chain chamber 14 through the upper space 131 to the breather chamber 137 together with the gas containing the mist of lubricating oil R3 in the chain chamber 14. Then, when the pressure in the gear chamber 13 exceeds a predetermined pressure, the gas is discharged from the breather hole 137a.

[0155] As a result, by utilizing the breather chamber 137 and breather hole 137a of the lubricating oil R3 that lubricates the reduction gear 30 and the power transmission chain 40 in order to maintain the storage section 622 at or below a predetermined pressure, it is not necessary to provide a separate breather chamber and breather hole for maintaining the storage section 622 at or below a predetermined pressure, and the drive unit 10 can be made smaller.

[0156] Furthermore, since the storage section 622 is provided at a position separated from the motor chamber 12 across the chain chamber 14, the storage section 622 can be provided at a position separated from the motor chamber 12 without increasing the size of the drive unit 10. In addition, by providing the breather chamber 137 at a position adjacent to the accommodation chamber 130 and the motor chamber 12, the breather chamber 137 can be provided by effectively utilizing the dead space generated between the accommodation chamber 130 and the motor chamber 12, so that the drive unit 10 can be made smaller.

[0157] Furthermore, since the reservoir 622 can be configured not to directly communicate with the outside of the drive unit 10, it is possible to prevent foreign matter or moisture from entering the second temperature adjustment circuit 62 from the outside of the drive unit 10.

[0158] Although one embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. In addition, the components in the above embodiment may be arbitrarily combined within the scope of the invention.

[0159] For example, in this embodiment, the breather chamber 137 and the breather hole 137a are provided in the right main case 115, but they may be provided in the left main case 114. In this case, the breather chamber 137 may be provided instead of the differential-side upper storage portion 131b.

[0160] Further, in this embodiment, the breather chamber 137 and the breather hole 137a are provided adjacent to the gear chamber 13, but they may be provided adjacent to the chain chamber .

[0161] This specification describes at least the following items. In parentheses, components corresponding to the above-described embodiment are shown as examples, but the present invention is not limited to these.

[0162] (1) a drive motor (drive motor 20); a drive unit case (drive unit case 11) having a motor chamber (motor chamber 12) for accommodating the drive motor; a heat exchanger (oil cooler 63) for cooling a coolant (motor cooling oil R2) for cooling the drive motor; A reservoir (reservoir 622) for storing the cooling liquid; A drive unit (drive unit 10) comprising: The drive unit case is provided with a buffer chamber (chain chamber 14) adjacent to the motor chamber and partitioned from the motor chamber by a partition wall (first partition wall 114a), the buffer chamber being separate from the motor chamber. The storage section is provided at a position separated from the motor chamber across the buffer chamber. Drive unit.

[0163] According to (1), by isolating the storage section from the motor chamber, which is the heat source, and sandwiching a buffer chamber between the storage section and the motor chamber, the heat generated in the motor chamber can be prevented from being transferred to the storage section, and the coolant stored in the storage section can be maintained at a low temperature.

[0164] (2) A drive unit according to (1), The drive unit is provided with a coolant communication pipe (oil cooler communication pipe 623) that connects the motor chamber and the heat exchanger, The cooling liquid discharged from the motor chamber is supplied to the heat exchanger through the cooling liquid communication pipe. Drive unit.

[0165] According to (2), the coolant discharged from the motor chamber is supplied to the heat exchanger through the coolant connection pipe. This makes it possible to supply the coolant discharged from the motor chamber to the heat exchanger separated from the motor chamber with a simple structure.

[0166] (3) A drive unit according to (1), The drive unit case is provided with a communication hole (communication hole 136a) that communicates between the heat exchanger and the storage section, The cooling liquid supplied to the heat exchanger and cooled by the heat exchanger flows into the storage portion through the communication hole and is stored in the storage portion. Drive unit.

[0167] According to (3), a flow path connecting the heat exchanger and the storage section can be formed with a simple structure.

[0168] (4) A drive unit according to (1), The motor chamber is provided with a coolant introduction section (oil introduction section 126) for introducing the coolant thereinto, The drive unit includes: A coolant pump (oil pump 621) for pumping the coolant; a coolant supply passage (oil supply passage 624) connecting the coolant pump and the coolant introduction portion of the motor chamber, The coolant pump pumps the coolant stored in the storage portion and supplies the coolant to an inside of the motor chamber through the coolant supply passage. Drive unit.

[0169] According to (4), by using a coolant pump to pump the coolant stored in a storage tank located away from the motor chamber, which is the heat source, and introducing the coolant into the motor chamber through the coolant inlet of the motor chamber, a cooler coolant can be supplied to the motor chamber, thereby improving the cooling efficiency of the drive motor.

[0170] (5) A drive unit according to (4), The drive unit is provided with a coolant communication pipe (oil cooler communication pipe 623) that connects the motor chamber and the heat exchanger, The cooling liquid discharged from the motor chamber is supplied to the heat exchanger through the cooling liquid communication pipe, the coolant communication pipe and the coolant supply flow path are provided separately on one side and the other side opposed to each other with the drive motor therebetween; Drive unit.

[0171] According to (5), the cooling liquid communication pipe and the cooling liquid supply flow path are provided at a distance from each other on one side and the other side of the drive motor, respectively, so that the cooling liquid flowing through the cooling liquid supply flow path can be prevented from being heated by the cooling liquid flowing through the cooling liquid communication pipe.

[0172] (6) A drive unit according to any one of (1) to (5), A partition wall (partition wall 112a) separating the storage section and the buffer chamber is provided with a storage section breather hole (breather hole 112b) at a position that is the upper part of the storage section, the storage section breather hole communicating with the buffer chamber and the storage section. Drive unit.

[0173] According to (6), when the pressure in the storage portion exceeds a predetermined pressure, gas containing a mist of cooling liquid is released from the storage portion breather hole into the buffer chamber, thereby maintaining the pressure in the storage portion below the predetermined pressure.

[0174] (7) A drive unit according to (6), The drive unit includes: a reduction gear (reduction gear 30) that reduces the power output from the drive motor and outputs it to the outside; a power transmission member (power transmission chain 40) that transmits the power output from the drive motor to the reduction gear device, The reduction gear and the power transmission member are lubricated by a lubricating fluid (lubricating oil R3), The cooling liquid and the lubricating liquid are liquids of the same composition. Drive unit.

[0175] According to (7), since the lubricating liquid and the coolant are liquids of the same composition, the pressure in the storage section can be maintained below a predetermined pressure using a breather path for the lubricating liquid that lubricates the reduction gear and the power transmission components. Therefore, the breather path for the coolant stored in the storage section can be shared with the breather path for the lubricating liquid that lubricates the reduction gear and the power transmission components, and the drive unit can be made smaller.

[0176] (8) A drive unit according to (7), The drive unit case includes: An accommodation chamber (accommodation chamber 130) that accommodates the reduction gear; A breather chamber (breather chamber 137) adjacent to the accommodation chamber and the motor chamber, The buffer chamber is a power transmission member accommodating chamber (chain chamber 14) that accommodates the power transmission member, The breather chamber is provided with a breather hole (breather hole 137a) that communicates with the outside of the drive unit case. Drive unit.

[0177] According to (8), by utilizing a breather chamber and a breather hole for the lubricating liquid that lubricates the reduction gear and the power transmission components in order to maintain the storage section at or below a predetermined pressure, it is not necessary to provide a separate breather chamber and breather hole for maintaining the storage section at or below a predetermined pressure, and the drive unit can be made smaller. Furthermore, since the reservoir is provided at a position separated from the motor chamber across the power transmission member accommodation chamber, the reservoir can be provided at a position separated from the motor chamber without increasing the size of the drive unit. In addition, by providing the breather chamber at a position adjacent to the accommodation chamber and the motor chamber, the dead space between the accommodation chamber and the motor chamber can be effectively utilized to provide the breather chamber, thereby making it possible to reduce the size of the drive unit. Furthermore, since the reservoir can be configured not to communicate directly with the outside of the drive unit, it is possible to prevent foreign matter or moisture from outside the drive unit from entering the temperature control circuit that controls the temperature of the drive motor. [Explanation of symbols]

[0178] 10 Drive unit 11 Drive unit case 112a Partition wall 112b Breather hole (reservoir breather hole) 114a 1st Compartment Wall (Compartment Wall) 126 Oil inlet (coolant inlet) 12 Motor Room 130 Containment Room 136a Communication hole 137 Breather Room 137a Breather hole 14 Chain chamber (buffer chamber, power transmission member housing chamber) 20 Drive motor 30 Reducer 40 Power transmission chain (power transmission component) 621 Oil pump (coolant pump) 622 Storage section 623 Oil cooler connection pipe (coolant connection pipe) 624 Oil supply passage (coolant supply passage) 63 Oil cooler (heat exchanger) R2 Motor cooling oil (coolant) R3 Lubricating oil (lubricating fluid)

Claims

1. A drive motor; a drive unit case having a motor chamber for accommodating the drive motor; a heat exchanger for cooling a cooling liquid for cooling the drive motor; a reservoir for storing the cooling liquid; A drive unit comprising: a buffer chamber adjacent to the motor chamber and separated from the motor chamber by a partition wall is formed in the drive unit case; The storage section is provided at a position separated from the motor chamber across the buffer chamber. Drive unit.

2. 2. A drive unit according to claim 1, the drive unit is provided with a coolant communication pipe that communicates between the motor chamber and the heat exchanger, The cooling liquid discharged from the motor chamber is supplied to the heat exchanger through the cooling liquid communication pipe. Drive unit.

3. 2. A drive unit according to claim 1, The drive unit case is provided with a communication hole that communicates between the heat exchanger and the storage portion, The cooling liquid supplied to the heat exchanger and cooled by the heat exchanger flows into the storage portion through the communication hole and is stored in the storage portion. Drive unit.

4. 2. A drive unit according to claim 1, The motor chamber is provided with a coolant introduction portion for introducing the coolant thereinto, The drive unit includes: A coolant pump that pumps the coolant; a coolant supply passage that connects the coolant pump and the coolant introduction portion of the motor chamber, The coolant pump pumps the coolant stored in the storage portion and supplies the coolant to an inside of the motor chamber through the coolant supply passage. Drive unit.

5. A drive unit according to claim 4, the drive unit is provided with a coolant communication pipe that communicates between the motor chamber and the heat exchanger, The cooling liquid discharged from the motor chamber is supplied to the heat exchanger through the cooling liquid communication pipe, the coolant communication pipe and the coolant supply flow path are provided separately on one side and the other side opposed to each other with the drive motor therebetween; Drive unit.

6. A drive unit according to any one of claims 1 to 5, A partition wall separating the storage section and the buffer chamber is provided with a storage section breather hole at a position that is an upper portion of the storage section, the storage section communicating with the buffer chamber and the storage section. Drive unit.

7. A drive unit according to claim 6, The drive unit includes: a reduction gear device that reduces the speed of the power output from the drive motor and outputs the reduced speed to the outside; a power transmission member that transmits the power output from the drive motor to the reduction gear device, the reduction gear and the power transmission member are lubricated by a lubricating liquid, The cooling liquid and the lubricating liquid are liquids of the same composition. Drive unit.

8. A drive unit according to claim 7, The drive unit case includes: an accommodation chamber that accommodates the reduction gear; a breather chamber adjacent to the accommodation chamber and the motor chamber, the buffer chamber is a power transmission member accommodating chamber that accommodates the power transmission member, The breather chamber is provided with a breather hole communicating with the outside of the drive unit case. Drive unit.

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