Drive unit

Abstract

The invention provides a drive unit which can make the vertical size compact without reducing the cooling efficiency of a coil. A drive unit (10) is provided with: a drive motor (20); and a drive unit case (11) having a motor chamber (12). A stator (23) of the driving motor is immersed in motor cooling oil (R2) introduced into the motor chamber from the oil introduction part (126) and is cooled. An oil discharge portion (127) for discharging motor cooling oil from the motor chamber is provided in a left wall portion (122) of the motor chamber. A spacer (128) is provided between the oil discharge portion (127) of the motor chamber and the stator. The spacer extends such that the upper end (128a) thereof is higher than the upper end of a coil (232) of the driving motor. A communication space (125c) through which motor cooling oil (R2) flows is formed between an upper end portion (128a) of the spacer and the drive unit housing (11).

Description

Technical Field

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

[0002] In recent years, efforts to realize a low-carbon society or a decarbonized society have been actively carried out, and research related to electrification technology has been conducted in order to reduce CO2 emissions and improve energy efficiency in vehicles.

[0003] In vehicle electrification technology, in order to increase the degree of freedom of installation in the vehicle, the drive unit is required to be miniaturized, especially the height dimension is required to be suppressed. In addition, in order to improve power consumption and cruising range, it is required to transmit power efficiently.

[0004] For example, Patent Document 1 describes a motor unit, in which a housing that contains a motor is divided into a rotor side and a coil by a partition wall, and a coolant flow path is formed around the coil, which is surrounded by the coil side surface of the partition wall and the inner circumferential surface of the housing. In the motor unit described in Patent Document 1, the partition wall prevents the coolant from entering the air gap between the rotor and the stator core, so an air layer is formed between the rotor and the stator core. Generally, the viscous resistance of air is lower than the viscous resistance of the coolant. Therefore, since the coolant does not enter between the rotor and the stator but forms an air layer between the rotor and the stator, it is possible to reduce energy loss when the motor is driven to rotate the rotor.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-165411 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the motor unit described in Patent Document 1, the coolant inlet for introducing the coolant into the coolant flow path, and the coolant outlet for discharging the coolant from the coolant flow path are both provided in the coolant flow path in a manner protruding upward from the upper portion of the housing. Therefore, there is a problem that the upper and lower dimensions of the motor unit become larger. On the other hand, if the coolant inlet and the coolant outlet, especially the coolant outlet, are provided on the horizontal wall of the motor unit, that is, the front, back, left and right walls, the height of the coolant level in the coolant flow path cannot be located at a position higher than the coolant outlet, so the coil cannot be fully immersed in the coolant, resulting in a problem that the cooling efficiency of the coil is reduced.

[0010] The present invention provides a drive unit which can make the upper and lower dimensions compact without reducing the cooling efficiency of the coil.

[0011] Solutions to Solve Problems

[0012] The present invention relates to a driving unit, comprising:

[0013] a driving motor having a rotor and a stator; and

[0014] a drive unit housing having a motor chamber for accommodating the drive motor,

[0015] in,

[0016] The stator comprises a stator core and a coil mounted on the stator core.

[0017] The drive unit housing is provided with:

[0018] a coolant introduction portion for introducing coolant into the motor chamber; and

[0019] a coolant discharge portion for discharging the coolant from the motor chamber,

[0020] The stator is immersed in the coolant introduced into the motor chamber from the coolant introduction portion and is cooled by the coolant.

[0021] The coolant discharge portion is disposed on a first wall portion of the motor chamber facing in a horizontal direction.

[0022] A spacer is provided in the motor chamber between the coolant discharge portion and the stator in the axial direction of the drive motor and at a position overlapping with the coolant discharge portion when viewed from the axial direction of the drive motor.

[0023] The spacer extends in the vertical direction so that the upper end portion is located higher than the upper end of the coil of the drive motor.

[0024] A communication space for the coolant to flow is formed between the upper end of the spacer and the drive unit housing.

[0025] The coolant flows in the communication space and is discharged from the coolant discharge portion to the outside of the motor chamber.

[0026] Effects of the Invention

[0027] According to the present invention, the vertical dimensions of the drive unit can be made compact without reducing the cooling efficiency of the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a vehicle equipped with a drive unit according to an embodiment of the present invention, as viewed from the left.

[0029] Figure 2 This is a perspective view showing a partially cutaway view of a drive unit according to an embodiment of the present invention.

[0030] Figure 3 It is used to illustrate Figure 2 A partially cutaway stereoscopic view of a power transmission path in a drive unit.

[0031] Figure 4 yes Figure 2 Skeleton diagram of the reduction gear in the drive unit.

[0032] Figure 5 yes Figure 2 Top and left side views of the drive unit.

[0033] Figure 6 Observed from the left Figure 2 A perspective view of the left main housing of the drive unit.

[0034] Figure 7 yes Figure 5 AA line section view.

[0035] Figure 8 Observed from the right Figure 2 A perspective view of the left main housing of the drive unit.

[0036] Fig. 9 Observed from the left Figure 2 A perspective view of the right main housing of the drive unit.

[0037] Fig.10 yes Figure 5 BB line cross-sectional view.

[0038] Fig.11 yes Figure 2 Block diagram of the temperature control system in the drive unit.

[0039] Fig.12 is Figure 2 A sectional view of a drive unit cut along the left-right direction with the axis of the drive shaft as the axis and viewed from the rear.

[0040] Fig.13 yes Fig.12 A sectional perspective view near the spacer.

[0041] Fig.14 yes Fig.12 A sectional stereoscopic view of the vicinity of the oil discharge portion.

[0042] Fig.15 is Figure 2 A schematic diagram showing a drive unit cut along the left-right direction in a manner intersecting the storage portion.

[0043] Fig.16 Yes Figure 2 A three-dimensional view of the vicinity of the storage portion cut along the left-right direction.

[0044] Fig.17 Yes Figure 2 A stereoscopic view of a portion of a drive unit cut away along the left-right direction.

[0045] Fig.18 Yes Figure 2 A stereoscopic view of a portion of a drive unit cut away along the left-right direction.

[0046] Fig.19 yes Figure 2 A perspective view of the right main housing of the drive unit.

[0047] Description of reference numerals:

[0048] 10 drive units

[0049] 11Driver unit housing

[0050] 12 Motor room

[0051] 122 left wall portion (first wall portion)

[0052] 123 right wall portion (second wall portion)

[0053] 125c Connected Space

[0054] 126 Oil inlet (coolant inlet)

[0055] 127 Oil discharge part (coolant discharge part)

[0056] 128 spacers

[0057] 128a Upper end

[0058] 20 Driving motor

[0059] 22 rotors

[0060] 23 stator

[0061] 231 stator core

[0062] 232 Coil

[0063] 24 Sealing cover (next wall component)

[0064] R2 Motor cooling oil (coolant). DETAILED DESCRIPTION

[0065] Hereinafter, a vehicle equipped with a drive unit according to an embodiment of the present invention will be described based on the accompanying drawings. In addition, the accompanying drawings are viewed along the directions indicated by the accompanying drawings. In addition, in this specification, etc., in order to make the description simple and clear, the front and rear, left and right, and up and down directions are described according to the directions observed from the driver of the vehicle. In the accompanying drawings, the front of the vehicle is represented as Fr, the rear is represented as Rr, the left is represented as L, the right is represented as R, the top is represented as U, and the bottom is represented as D.

[0066]

Overall structure of the vehicle

[0067] like Figure 1 As shown, the vehicle V of this embodiment has a pair of left and right front wheels FW and a pair of left and right rear wheels RW, and a bottom panel FP constituting the bottom surface of the vehicle V. The vehicle V is divided into a vehicle compartment CB and a front cabin FRM in front thereof by a front control panel DP extending in the up-down direction above the bottom panel FP. Front seats FS and rear seats RS are provided in the vehicle compartment CB.

[0068] The vehicle V includes a drive unit 10 as a drive source, a battery pack IPU for storing power supplied to the drive unit 10, a charging and supply control device CHGR for controlling the input and output power of the battery pack IPU, a power receiving unit PR capable of receiving power from an external power source, a radiator 611 for circulating cooling water R1 for cooling a control device 50 described later of the drive unit 10, and a cooling water pump 612 for pressurizing and delivering the cooling water R1. The cooling water R1 is, for example, cooling water called LLC (Long Life Coolant).

[0069] The drive unit 10 is arranged below the floor panel FP behind the rear seat RS. The battery pack IPU is arranged below the bottom surface of the vehicle compartment CB below the floor panel FP. The battery pack IPU accommodates a plurality of battery modules in which a plurality of cells are stacked. Each cell is a secondary battery capable of charge and discharge, such as a lithium-ion battery or an all-solid-state battery.

[0070] The charging and power supply control device CHGR is accommodated in the front compartment FRM. The power receiving unit PR is provided on the upper surface of the front compartment FRM and is electrically connected to the charging and power supply control device CHGR. The radiator 611 is accommodated in the front compartment FRM and is arranged near the front end in the front compartment FRM. The radiator 611 is a heat exchanger that cools the cooling water R1 by utilizing the heat exchange between the external air of the vehicle V and the circulating cooling water R1. The cooling water pump 612 is accommodated in the front compartment FRM.

[0071] [Overall structure of the drive unit]

[0072] like Figure 2 and Figure 3As shown, the drive unit 10 includes a drive motor 20, a reduction gear 30 that reduces 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 pressurizes and delivers motor cooling oil R2, and an oil cooler 63 that performs heat exchange between cooling water R1 and motor cooling oil R2. The motor cooling oil R2 is, for example, an oil called ATF (Automatic Transmission Fluid; automatic transmission fluid).

[0073] In the drive unit 10, the drive motor 20, the reduction gear 30, the power transmission chain 40, and the control device 50 are accommodated in the drive unit case 11. The oil pump 621 and the oil cooler 63 are mounted on the left side surface of the drive unit case 11.

[0074] The driving motor 20 is a so-called inner rotor type motor, which includes a driving shaft 21, a rotor 22 mounted on the driving shaft 21 and rotating integrally with the driving shaft 21, and a stator 23 arranged to be radially opposed to the rotor 22 with a small gap radially outside the rotor 22.

[0075] In this embodiment, the drive motor 20 is arranged in the drive unit 10 with its axial direction (ie, the drive shaft 21) oriented horizontally in the left-right direction. Thus, by arranging the drive shaft 21 oriented horizontally, the vertical dimension of the drive unit 10 can be made compact.

[0076] The stator 23 includes a stator core 231 and a coil 232 mounted on the stator core 231 and composed of a plurality of windings such as a U-phase, a V-phase, and a W-phase.

[0077] The stator core 231 is formed by laminating a plurality of thin electromagnetic steel plates having a substantially annular shape in the axial direction.

[0078] The stator core 231 includes: a yoke 231a, which is substantially annular when viewed from the axial direction, forming an outer ring portion of the stator core 231; and a plurality of teeth 231b, which protrude radially from the inner peripheral surface of the yoke 231a toward the center. The plurality of teeth 231b are arranged at equal intervals along the circumferential direction of the stator core 231 when viewed from the axial direction. A groove 231c is formed between adjacent teeth 231b in the circumferential direction of the stator core 231. A plurality of grooves 231c are formed at equal intervals along the circumferential direction of the stator core 231. Each tooth 231b and groove 231c extends along the axial direction of the stator core 231.

[0079] The coil 232 is composed of a plurality of conductor segments inserted into the slots 231 c of the stator core 231 . The conductor segments are inserted into all of the slots 231 c formed in a plurality along the circumferential direction of the stator core 231 .

[0080] The coil 232 has a left coil end 232L protruding axially outward from a left end surface on one axial side of the stator core 231 , and a right coil end 232R protruding axially outward from a right end surface on the other axial side of the stator core 231 .

[0081] A drive sprocket 21a around which a power transmission chain 40 is wound is attached to the left end portion of the drive shaft 21. The drive sprocket 21a rotates integrally with the drive shaft 21.

[0082] like Figure 3 and Figure 4 As shown, the reduction gear device 30 includes a planetary gear mechanism 31 and a differential gear mechanism 32 .

[0083] First, the planetary gear mechanism 31 will be described.

[0084] The planetary gear mechanism 31 includes an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinion gears 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0085] In the present embodiment, the planetary gear mechanism 31 is arranged in the front-to-back direction behind the driving motor 20. The planetary gear mechanism 31 is arranged so that the axial direction (i.e., the input shaft 311) is parallel to the axial direction of the driving motor 20 and faces the left-right direction. In addition, the input shaft 311 of the planetary gear mechanism 31 is arranged at a position at substantially the same height as the driving shaft 21 of the driving motor 20 in the vertical direction. In addition, the outer diameter of the planetary gear mechanism 31 is substantially the same as the outer diameter of the driving motor 20, and the height of the driving unit 10 in the vertical direction is low.

[0086] The input shaft 311 is a hollow shaft, and the left drive shaft described later passes through the inside of the input shaft 311. A driven sprocket 311a around which the power transmission chain 40 is wound is mounted at the left end of the input shaft 311. The driven sprocket 311a rotates integrally with the input shaft 311. The diameter of the driven sprocket 311a is larger than the diameter of the drive sprocket 21a mounted on 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.

[0087] 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.

[0088] A plurality of pinion shafts 313 are arranged at equal intervals in the circumferential direction on the radially outer side of the sun gear 312 along the outer peripheral surface of the sun gear 312 in a manner parallel to the input shaft 311 and oriented in the left-right direction. In the present embodiment, four pinion shafts 313 are arranged at 90-degree intervals in the circumferential direction on the radially outer side of the sun gear 312 along the circumferential direction of the input shaft 311.

[0089] The stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b that rotate integrally is supported on each planetary pinion shaft 313 in a freely rotatable manner. In the present embodiment, the first planetary gear 314a is arranged on the left side and the second planetary gear 314b is arranged on the right side of each planetary pinion shaft 313. Therefore, four first planetary gears 314a and four second planetary gears 314b are arranged in a circular ring shape at intervals of 90 degrees along the circumference of the input shaft 311.

[0090] The first planetary gears 314a are external gears disposed on the outer circumference of the sun gear 312 and meshing with the sun gear 312. The four first planetary gears 314a are arranged in an annular shape at 90-degree intervals along the outer circumference of the sun gear 312. The four first planetary gears 314a mesh with the outer circumference of the sun gear 312, respectively.

[0091] The second planetary gears 314b are external gears disposed on the inner circumference of the ring gear 317 and meshing with the ring gear 317. Four second planetary gears 314b are arranged in an annular shape at 90 degree intervals along the inner circumference of the ring gear 317. In this embodiment, the second planetary gears 314b are external gears with a smaller diameter than the first planetary gears 314a.

[0092] The planetary carrier 316 is connected to the four planetary pinion shafts 313. The planetary carrier 316 and the four planetary pinion shafts 313 are integrally rotatable on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0093] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b freely rotates about the planetary pinion shaft 313, and freely revolves on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the planetary pinion shaft 313. Moreover, the planet carrier 316 rotates on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the revolving motion of the stepped pinion 314.

[0094] The ring gear 317 is an annular internal gear, and is disposed so as to surround the four annularly disposed second planetary gears 314b, and its inner peripheral surface meshes with each second planetary gear 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.

[0095] Next, the differential gear mechanism 32 will be described.

[0096] 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 supported by the differential pinion shaft 322 and freely rotatable, 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.

[0097] 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 a housing portion 321a that houses the differential pinion shaft 322, the first bevel gear 323a, the second bevel gear 323b, the left gear 324L, and the right gear 324R.

[0098] The differential pinion shaft 322 is accommodated in the accommodating portion 321a of the differential case 321 and is supported by the differential case 321. The differential pinion shaft 322 is arranged in the accommodating portion 321a of the differential case 321 in a manner orthogonal to the rotation axis of the differential case 321. The differential pinion shaft 322 rotates integrally with the differential case 321 about the rotation axis of the differential case 321.

[0099] The first bevel gear 323a is accommodated in the accommodating portion 321a of the differential case 321 and is rotatably supported on the differential pinion shaft 322. The first bevel gear 323a has a substantially truncated cone shape, with its upper surface facing the rotation axis of the differential case 321 and a gear formed on the side surface of the truncated cone.

[0100] The second bevel gear 323b is accommodated in the accommodating portion 321a of the differential case 321, opposite to the first bevel gear 323a, and is rotatably supported on the differential pinion shaft 322. The second bevel gear 323b has a substantially truncated cone shape, with its upper surface facing the rotation axis of the differential case 321, and a gear formed on the side of the truncated cone.

[0101] The left side gear 324L is accommodated in the accommodating portion 321a of the differential case 321, and is disposed between the first bevel gear 323a and the second bevel gear 323b on the left side of the differential pinion shaft 322. 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 substantially truncated cone shape, and its upper surface faces the differential pinion shaft 322 (i.e., the right side), and a gear is formed on the side of the truncated cone. Moreover, the left side gear 324L meshes with both the first bevel gear 323a and the second bevel gear 323b.

[0102] The right side gear 324R is accommodated in the accommodating portion 321a of the differential case 321, and is arranged between the first bevel gear 323a and the second bevel gear 323b on the right side of the differential pinion shaft 322, opposite to the left side gear 324L in the left-right direction across the differential pinion shaft 322. 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 its upper surface facing the differential pinion shaft 322 (i.e., in the left direction), and a gear is formed on the side of the truncated cone. Moreover, the right side gear 324R meshes with both the first bevel gear 323a and the second bevel gear 323b.

[0103] 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 gear 324L mounted on the right end, and a left rear wheel RW mounted on the left end. Therefore, the left gear 324L, the left drive shaft 325L, and the left rear wheel RW rotate integrally.

[0104] 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 gear 324R mounted on the left end, and a right rear wheel RW mounted on the right end. Therefore, the right gear 324R, the right drive shaft 325R, and the right rear wheel RW rotate integrally.

[0105] In this way, the differential case 321 is formed integrally with the carrier 316 of the planetary gear mechanism 31 , so that the planetary gear mechanism 31 and the differential gear mechanism 32 can be integrally structured, and the reduction gear device 30 can be further miniaturized.

[0106] Next, a power transmission path of the power output from the driving motor 20 will be described.

[0107] The power generated by the driving motor 20 is output from the driving shaft 21, and the driving sprocket 21a installed on the driving shaft 21 rotates integrally with the driving shaft 21. Moreover, when the driving sprocket 21a rotates, the driven sprocket 311a rotates due to the power transmission chain 40 wound on the driving sprocket 21a and the driven sprocket 311a installed on the input shaft 311 of the planetary gear mechanism 31. Moreover, the input shaft 311 of the planetary gear mechanism 31 rotates integrally with the driven sprocket 311a. At this time, the number of teeth of the driven sprocket 311a is greater than the number of teeth of the driving sprocket 21a, so the rotation of the driving shaft 21 is reduced and input to the input shaft 311 of the planetary gear mechanism 31 via the driving sprocket 21a, the power transmission chain 40 and the driven sprocket 311a.

[0108] In the planetary gear mechanism 31, the power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. And, the stepped pinion 314 rotates while revolving. And, the planet carrier 316 rotates integrally with the revolving 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 and transmitted to the planet carrier 316 at a predetermined reduction ratio.

[0109] In the differential gear mechanism 32, the differential case 321 is integrally formed with the carrier 316 of the planetary gear mechanism 31, and thus rotates integrally with the rotation of the carrier 316. Therefore, the power input to the input shaft 311 of the planetary gear mechanism 31 is reduced in speed via the carrier 316 and input to the differential case 321 at a predetermined reduction ratio.

[0110] 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 about the rotation axis of the differential case 321 .

[0111] When the vehicle V is traveling straight, there is no rotation difference 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 accordance with the rotation of the differential pinion shaft 322. In addition, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the left rear wheel RW, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the right rear wheel RW.

[0112] When the vehicle V turns, the differential pinion shaft 322 revolves, and the first bevel gear 323a and the second bevel gear 323b rotate to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn, and 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 to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn. Moreover, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the rear wheel RW on the left side, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the rear wheel RW on the right side. Therefore, when the vehicle V turns, the left drive shaft 325L and the right drive shaft 325R rotate in a manner that slows down the rotation speed of the rear wheel RW on the inner side of the turn and speeds up the rotation speed of the rear wheel RW on the outer side of the turn.

[0113] In this way, Figure 3 As shown by the arrow, the power output from the driving motor 20 is decelerated via the driving sprocket 21a, the driven sprocket 311a and the power transmission chain 40 and input into the reduction device 30, 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.

[0114] Furthermore, by using the planetary gear mechanism 31 in the speed reduction mechanism, it is possible to obtain a desired speed reduction ratio while suppressing an increase in the radial dimension relative to the rotation axis direction.

[0115] Next, refer to Figures 5 to 10 The drive unit case 11 will be described.

[0116] The drive unit case 11 includes a main case 111, a left cover 112 covering the left side of the main case 111, and a right cover 113 covering the right side of the main case 111. The main case 111 is divided into a left main case 114 and a right main case 115.

[0117] The main housing 111 is divided into a motor chamber 12 for accommodating a driving motor 20, a gear chamber 13 for accommodating a reduction gear 30, a chain chamber 14 for accommodating a power transmission chain 40, and a controller chamber 15 for accommodating a control device 50. The motor chamber 12 and the gear chamber 13 are arranged side by side in the front-to-back 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 on 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 on the right.

[0118] The left side cover 112 covers the opening on the left side of the chain chamber 14. To the left side surface of the left side cover 112, an oil pump 621 and an oil cooler 63 are fixed.

[0119] like Figures 6 to 8 As shown, 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 partitions the motor chamber 12 and the chain chamber 14, and a second partition wall 114b that partitions the motor chamber 12 and 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.

[0120] The left main housing 114 has an opening on the right side of the motor chamber 12. In addition, in the left main housing 114, the gear chamber 13 is connected to the chain chamber 14, but the left main housing 114 is provided with a baffle 116 (see also FIG. 116 ) that separates the gear chamber 13 and the chain chamber 14. Figure 4 The baffle plate 116 extends between the driven sprocket 311 a and the sun gear 312 in the up-down direction and the front-rear direction.

[0121] like Fig. 9 and Fig.10 As shown, the right main housing 115 includes: a right wall portion 123 that covers the opening on the right side of the motor chamber 12 formed in the left main housing 114, and further includes: a right wall portion 133 that covers the opening on the right side of the gear chamber 13 formed in the left main housing 114; and a third partition wall 115a that partitions the motor chamber 12 and the gear chamber 13. In addition, the right main housing 115 forms a controller chamber 15 on the right side of the right wall portion 123 including the front side area of ​​the right wall portion 133. In the right main housing 115, the right side of the controller chamber 15 is open.

[0122] The right side cover 113 covers the opening on the right side of the controller room 15 .

[0123] (Temperature Control System)

[0124] like Fig.11 As shown, a temperature control system 60 is configured in the vehicle V. The temperature control system 60 includes: a first temperature control circuit 61, through which the aforementioned cooling water R1 circulates to control the temperature of the control device 50; a second temperature control circuit 62, through which the aforementioned motor cooling oil R2 circulates to control the temperature and lubricate the drive motor 20; and the aforementioned oil cooler 63. As described above, the oil cooler 63 performs heat exchange between the cooling water R1 circulating in the first temperature control circuit 61 and the motor cooling oil R2 circulating in the second temperature control circuit 62.

[0125] 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 under pressure from the cooling water pump 612 is supplied to the control device 50 to control the temperature of the control device 50, supplied from the control device 50 to the oil cooler 63 to perform heat exchange with the motor cooling oil R2 flowing in the second temperature control circuit 62, supplied to the radiator 611, cooled by heat exchange with the outside air, and returned to the cooling water pump 612.

[0126] 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. In addition, a storage portion 622 is formed inside the drive unit housing 11, which is used to temporarily store the motor cooling oil R2 cooled by the oil cooler 63. The motor cooling oil R2 temporarily stored in the storage portion 622 is pressurized and transported from the oil pump 621, and is supplied to the inside of the drive unit housing 11 to control the temperature of the drive motor 20. In addition, after the motor cooling oil R2 is supplied from the drive unit housing 11 to the oil cooler 63, it exchanges heat with the cooling water R1 flowing in the first temperature control circuit 61, is cooled, and then flows into the storage portion 622 and is temporarily stored in the storage portion 622 again.

[0127] In the gear chamber 13 and the chain chamber 14 separated by the baffle 116, a lubricating oil R3 is stored as a common fluid. The lubricating oil R3 is, for example, an oil called ATF (Automatic Transmission Fluid). The lubricating oil R3 is an oil of the same composition as the motor cooling oil R2. The lubricating oil R3 is used to lubricate the reduction gear 30 provided in the gear chamber 13, the driving sprocket 21a provided in the chain chamber 14, the driven sprocket 311a, and the power transmission chain 40. In addition, although the mist-like motor cooling oil R2 of the second temperature control circuit 62 may be released into the gear chamber 13 from the air vent 112b described later, the lubricating oil R3 does not flow into the second temperature control circuit 62.

[0128] Next, refer to Figures 12 to 17 The flow path of the motor cooling oil R2 in the motor chamber 12 in the second temperature control circuit 62 of the temperature control system 60 will be described.

[0129] like Fig.12 As shown, the left main housing 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 housing 115 forms a right wall portion 123 of the motor chamber 12.

[0130] In the left main housing 114, a cylindrical outer peripheral wall portion 121 covers the outer periphery of the drive motor 20. A 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 housing 115, a right wall portion 123 abuts against the right end of the outer peripheral wall portion 121 of the left main housing 114 and covers the right side of the drive motor 20.

[0131] The left wall portion 122 includes an annular protruding wall portion 122a, which extends axially from the radially inner side of 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 overlapping with at least a portion of the left coil end portion 232L in the axial direction. An annular sealing groove 122b is formed on the outer peripheral surface of the annular protruding wall portion 122a, and an annular O-ring 122c is provided in the sealing groove 122b.

[0132] The right wall portion 123 includes an annular protruding wall portion 123a, which extends axially from the radial inner side of the right coil end portion 232R toward the axial center of the drive motor 20. The protruding wall portion 123a extends from the right wall portion 123 to a position overlapping with at least a portion of the right coil end portion 232R in the axial direction. An annular sealing groove 123b is formed on the outer peripheral surface of the annular protruding wall portion 123a, and an annular O-ring 123c is provided in the sealing groove 123b.

[0133] A cylindrical sealing wall member 124 is fitted on the outer peripheral surface of the annular protruding wall portion 123a. The outer peripheral surface of the protruding wall portion 123a and the inner peripheral surface of the cylindrical sealing wall member 124 are sealed by an O-ring 123c. The sealing wall member 124 extends axially to a position closer to the left end surface of the rotor 22 and the stator 23 of the driving motor 20 than the protruding wall portion 123a in the axial direction of the driving motor 20. An annular sealing groove 124b is formed near the left end portion of the outer peripheral surface of the sealing wall member 124, and an annular O-ring 124c is provided in the sealing groove 124b.

[0134] In the driving motor 20 , a seal cover 24 extending in a cylindrical shape along the inner peripheral surface of the stator 23 is provided in a radial gap between the rotor 22 and the stator 23 .

[0135] The left end of the seal cover 24 is fitted with the outer peripheral surface of the protruding wall portion 122a of the left wall portion 122. The outer peripheral surface of the protruding wall portion 122a and the inner peripheral surface of the left end of the seal cover 24 are sealed by an O-ring 122c.

[0136] The right end of the seal cover 24 is fitted to the outer peripheral surface of the seal wall member 124. The outer peripheral surface of the seal wall member 124 and the inner peripheral surface of the right end of the seal cover 24 are sealed by an O-ring 124c.

[0137] The space surrounded by the outer peripheral wall 121, the left wall 122, the protruding wall 122a, the sealing cover 24, the sealing wall member 124, the right wall 123, and the protruding wall 123a forms a motor chamber oil flow path 125 through which the motor cooling oil R2 flows. The motor chamber oil flow path 125 is a sealed space in the motor chamber 12.

[0138] The oil flow path 125 in the motor chamber includes: a left annular flow path 125L, which covers the left coil end 232L and is annular when observed from the axial direction of the drive motor 20; a right annular flow path 125R, which covers the right coil end 232R and is annular when observed from the axial direction of the drive motor 20; and an axial flow path 125A, which is formed by the groove portion 231c of the stator 23 on the radial outside of the sealing cover 24.

[0139] In the present embodiment, an oil introduction portion 126 for introducing the motor cooling oil R2 into the motor chamber oil flow path 125 is provided at the lower portion of the right annular flow path 125R. The oil introduction portion 126 is provided from the right wall portion 123 of the lower portion of the right annular flow path 125R toward the axial outer side. In addition, an oil discharge portion 127 for discharging the motor cooling oil R2 flowing through the motor chamber oil flow path 125 is provided at the upper portion of the left annular flow path 125L. The oil discharge portion 127 is provided from the left wall portion 122 of the upper portion of the left annular flow path 125L toward the axial outer side.

[0140] The motor cooling oil R2 pumped under pressure from the oil pump 621 is introduced into the oil introduction portion 126 (see Fig.15 ).

[0141] The motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber oil flow path 125 flows in the right annular flow path 125R and also flows from right to left in the axial flow path 125A. The motor cooling oil R2 flowing from right to left in the axial flow path 125A flows into the left annular flow path 125L, and the motor chamber oil flow path 125 is filled with the motor cooling oil R2.

[0142] When the motor chamber oil flow path 125 is filled with the motor cooling oil R2 , the stator 23 is immersed in the motor cooling oil R2 filling the motor chamber oil flow path 125 and is cooled by the motor cooling oil R2 .

[0143] 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 .

[0144] In this way, the motor cooling oil R2 filling the motor chamber oil flow path 125 is circulated, and the stator 23 is immersed in the motor cooling oil R2 filling the motor chamber oil flow path 125, thereby being cooled.

[0145] At this time, since the motor chamber oil flow path 125 is a sealed space in the motor chamber 12, the motor cooling oil R2 flowing in the axial flow path 125A does not contact the rotor 22 due to the seal cover 24. In addition, the gap between the seal cover 24 and the outer peripheral surface of the rotor 22 is not filled with the motor cooling oil R2 but becomes an air layer.

[0146] Since the viscous resistance of air is lower than the viscous resistance of the motor cooling oil R2 , the presence of an air layer between the outer peripheral surface of the rotor 22 and the inner peripheral surface of the stator 23 can reduce energy loss when the drive motor 20 is driven to rotate the rotor 22 .

[0147] like Figure 12 to Figure 14 As shown, a spacer 128 is provided at the upper portion of the left annular flow path 125L between the oil discharge portion 127 and the stator 23 in the axial direction of the drive motor 20 and at a position overlapping with the oil discharge portion 127 when viewed from the axial direction of the drive motor 20. The spacer 128 extends in the up-down direction and divides the upper portion of the left annular flow path 125L into a space on the left side (the oil discharge portion 127 side) and a space on the right side (the drive motor 20 side) in the axial direction of the drive motor 20.

[0148] A communication space 125 c is formed between an upper end portion 128 a of the spacer 128 and the main housing 111 of the drive unit housing 11 .

[0149] Therefore, the motor cooling oil R2 introduced from the oil introduction portion 126 into the motor chamber internal oil flow path 125 is stored in the space on the right side (the driving motor 20 side) at the upper portion inside the left annular flow path 125L.

[0150] Furthermore, in the upper part of the left annular flow path 125L, if the liquid level of the motor cooling oil R2 stored in the space on the right side of the spacer 128 (on the driving motor 20 side) exceeds the upper end portion 128a of the spacer 128, the motor cooling oil R2 flows from the connecting space 125c into the space on the left side of the spacer 128 (on the oil discharge portion 127 side), and is discharged from the oil discharge portion 127 to the outside of the oil flow path 125 in the motor chamber.

[0151] The spacer 128 extends in the up-down direction in such a manner that the upper end portion 128a is located higher than the upper end of the coil 232 of the drive motor 20. That is, the spacer 128 extends in the up-down direction so that the lower end portion of the communication space 125c formed between the upper end portion 128a of the spacer 128 and the main housing 111 of the drive unit housing 11 is located at a position where the upper end portion 128a is higher than the upper end of the coil 232 of the drive motor 20.

[0152] Therefore, in the motor chamber oil flow path 125, regardless of the position of the oil discharge portion 127, the motor cooling oil R2 is filled to a position higher than the upper end of the coil 232. Therefore, in the motor chamber oil flow path 125, even if the oil discharge portion 127 is set at a lower position, the coil 232 can be reliably immersed in the motor cooling oil R2 as a whole to be cooled, so that the oil discharge portion 127 can be set on the left wall portion 122 of the motor chamber 12 without reducing the cooling efficiency of the coil 232, and the upper and lower dimensions of the drive unit 10 can be made compact.

[0153] In addition, the oil discharge portion 127 is provided so that at least a portion thereof is located lower than an upper end portion 128 a of the spacer 128 in the up-down direction.

[0154] Thus, the motor cooling oil R2 that flows over the upper end portion 128a of the spacer 128 from the communication space 125c into the space on the left side of the spacer 128 (the oil discharge portion 127 side) can be more efficiently discharged to the outside of the motor chamber oil flow path 125.

[0155] In addition, the oil discharge portion 127 is provided on the left wall portion 122 of the motor chamber 12, and 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. As a result, the motor chamber oil flow path 125 can be reliably 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.

[0156] In addition, the oil discharge portion 127 is provided at the upper portion of the motor chamber 12, and the oil introduction portion 126 is provided at the lower portion of the motor chamber 12. In this way, by providing the oil introduction portion 126 at a position lower 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 can reliably flow in the vertical direction from the lower side to the upper side of the drive motor 20. As a result, the motor chamber oil flow path 125 can be reliably 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.

[0157] like Figures 14 to 17 As shown, the motor cooling oil R2 discharged from the oil discharge portion 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 portion 127 of the motor chamber 12 and the oil cooler 63 .

[0158] In the present embodiment, the chain chamber 14 is provided adjacent to the left side of the motor chamber 12, and the reservoir 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 reservoir 622.

[0159] The left side cover 112 is provided with a partition wall 112a that partitions the chain chamber 14 and the storage portion 622. Therefore, the chain chamber 14 and the storage portion 622 are partitioned by the partition wall 112a.

[0160] The reservoir 622 is formed in the left cover 112 so as to be open on the left. The drive unit case 11 further includes a reservoir cover 117 that closes the left side of the reservoir 622. The reservoir cover 117 is attached to the left side of the left cover 112. The reservoir 622 is closed on the left side by the reservoir cover 117.

[0161] Therefore, the storage portion 622 is provided at a position adjacent to the chain chamber 14 and separated from the motor chamber 12 via the chain chamber 14 .

[0162] Therefore, by separating the storage portion 622 from the motor chamber 12 serving as a heat source and placing the chain chamber 14 between the storage portion 622 and the motor chamber 12, it is possible to suppress the heat generated in the motor chamber 12 from being transferred to the storage portion 622, and to maintain the motor cooling oil R2 stored in the storage portion 622 at a low temperature.

[0163] The oil cooler 63 is attached to the left side surface of the reservoir cover 117 .

[0164] Thus, 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 connecting pipe 623. Thus, the motor cooling oil R2 discharged from the oil discharge portion 127 can be supplied to the oil cooler 63 separated from the motor chamber 12 with a simple structure.

[0165] The reservoir cover 117 has a through hole 117 a through which the motor cooling oil R2 discharged from the oil cooler 63 flows.

[0166] The motor cooling oil R2 cooled by heat exchange with the cooling water R1 circulating in the first temperature control circuit 61 in the oil cooler 63 flows into the reservoir 622 through the through hole 117 a and is stored in the reservoir 622 .

[0167] Thus, a flow path connecting the oil cooler 63 and the reservoir 622 can be formed with a simple structure.

[0168] An oil pump 621 for pressurizing and delivering the motor cooling oil R2 is mounted on the left side surface of the left cover 112 (see Figure 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 .

[0169] The oil pump 621 pumps the motor cooling oil R2 temporarily stored in the reservoir 622 under pressure, and supplies the oil to the motor chamber oil flow path 125 formed in the motor chamber 12 through the oil supply flow path 624 .

[0170] In this way, for the motor cooling oil R2 stored in the storage section 622 set at a position separated from the motor chamber 12 which serves as a heat source, the oil pump 621 introduces the motor cooling oil R2 from the oil inlet section 126 of the motor chamber 12 into the motor chamber 12, thereby being able to supply the motor cooling oil R2 with a lower temperature to the motor chamber 12, thereby improving the cooling efficiency of the drive motor 20.

[0171] In addition, when viewed from the direction of the rotation axis of the driving motor 20, the oil cooler connecting pipe 623 through which the R2 heated up by cooling the driving motor 20 flows is formed at a position forward of the rotation axis of the driving motor 20, and, conversely, the oil supply path 624 through which the motor cooling oil R2 cooled by the oil cooler 63 flows is formed at a position rearward of the rotation axis of the driving motor 20.

[0172] In this way, when viewed from the direction of the rotation axis of the driving motor 20, the oil cooler connecting pipe 623 and the oil supply flow path 624 are separated and arranged on one side and the other side opposite to each other across the driving motor 20, thereby preventing the motor cooling oil R2 flowing in the oil supply flow path 624 from being heated up due to the motor cooling oil R2 flowing in the oil cooler connecting pipe 623.

[0173] The partition wall 112 a is provided at a position above the storage portion 622 with an air hole 112 b that communicates between the chain chamber 14 and the storage portion 622 .

[0174] When the pressure in the reservoir 622 exceeds a predetermined pressure, the gas containing the motor cooling oil R2 in a mist state is released from the air vent 112 b to the chain chamber 14 , and the pressure in the reservoir 622 is maintained at or below the predetermined pressure.

[0175] In this way, since the lubricating oil R3 becomes an oil with the same composition as the motor cooling oil R2, the air permeability path of the chain chamber 14 and the gear chamber 13 can be used to maintain the pressure in the storage section 622 below the specified pressure. Therefore, the air permeability path of the motor cooling oil R2 stored in the storage section 622 and the air permeability path of the lubricating oil R3 for lubricating the reduction gear 30 and the power transmission chain 40 can be shared, which can make the drive unit 10 miniaturized.

[0176] Furthermore, as described above, although the mist-like motor cooling oil R2 of the second temperature regulating circuit 62 may be released from the air vent 112 b to the gear chamber 13 , the lubricating oil R3 does not flow into the second temperature regulating circuit 62 .

[0177] Thus, the lubricating oil R3 is not mixed into the motor cooling oil R2 , and thus it is possible to prevent the lubricating oil R3 , which is likely to contain a large amount of sludge, from being supplied to the driving motor 20 .

[0178] (Lubrication and cooling of gear and chain chambers)

[0179] like Figures 17 to 19 As shown, in the chain chamber 14, the lower portion of the driven sprocket 311a is immersed in the lubricating oil R3 stored in the lower portion of the chain chamber 14. Moreover, the lubricating oil R3 stored in the lower portion of the chain chamber 14 is carried up by the driven sprocket 311a, and the lubricating oil R3 carried up by the driven sprocket 311a lubricates and cools the driving sprocket 21a, the driven sprocket 311a, and the power transmission chain 40 and the like provided in the chain chamber 14.

[0180] Therefore, if the liquid level of the lubricating oil R3 in the chain chamber 14 is high, the pulling efficiency of the driven sprocket 311 a can be improved.

[0181] In the gear chamber 13, the lubricating oil R3 carried 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 reduction gear 30 is lubricated and cooled by the lubricating oil R3 supplied from the chain chamber 14.

[0182] Therefore, even if the height of the liquid level of the lubricating oil R3 in the gear chamber 13 is lowered by increasing the lubricating oil R3 discharged from the hollow input shaft 311, the reduction gear 30 can be sufficiently lubricated and cooled. Therefore, regarding the situation that the height of the liquid level of the lubricating oil R3 in the gear chamber 13 is lowered by increasing the lubricating oil R3 discharged from the hollow input shaft 311, the stirring resistance of the lubricating oil R3 by the rotation of the reduction gear 30 becomes smaller, and the loss when the reduction gear 30 rotates is reduced.

[0183] Thus, the liquid level of the lubricating oil R3 in the chain chamber 14 is preferably high, and the liquid level of the lubricating oil R3 in the gear chamber 13 is preferably low.

[0184] In addition, a housing chamber 130 for housing the planetary gear mechanism 31 and the differential gear mechanism 32 is formed in the gear chamber 13. The cross section of the housing chamber 130 when viewed from the rotation axis direction of the planetary gear mechanism 31 and the differential gear mechanism 32 has a substantially circular shape. A portion 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 portion of the housing chamber 130. The lower portion of the planetary gear mechanism 31 and the lower portion of the differential gear mechanism 32 are immersed in the lubricating oil R3 stored in the lower portion of the housing chamber 130. And, the lubricating oil R3 stored in the lower portion of the housing chamber 130 is brought up by the rotation of the planetary gear mechanism 31 and the differential gear mechanism 32, and is also lubricated and cooled by the lubricating oil R3 brought up by the rotation of the planetary gear mechanism 31 and the differential gear mechanism 32.

[0185] In this embodiment, as described above, the left main case 114 communicates with the gear chamber 13 and the chain chamber 14, but the left main case 114 is provided with a baffle plate 116 that separates the gear chamber 13 from the chain chamber 14. The baffle plate 116 extends between the driven sprocket 311a and the sun gear 312 in the vertical direction and the front-rear direction.

[0186] Furthermore, the baffle plate 116 extends upward from the bottom of the chain chamber 14 and the gear chamber 13 , and restricts the flow of the lubricating oil R3 between the chain chamber 14 and the gear chamber 13 .

[0187] Thus, the liquid level of the lubricating oil R3 in the chain chamber 14 can be made different from the liquid level of the lubricating oil R3 in the gear chamber 13, and the liquid level of the lubricating oil R3 in the chain chamber 14 can be made higher while the liquid level of the lubricating oil R3 in the gear chamber 13 can be made lower. Therefore, the lubrication performance in the gear chamber 13 and the chain chamber 14 can be improved, and the stirring resistance of the lubricating oil R3 generated by the rotation of the reduction gear 30 can be reduced.

[0188] An upper space 131 is formed at the upper portion of the gear chamber 13. The upper space 131 is formed between the motor chamber 12 and the housing chamber 130 of the gear chamber 13. The upper space 131 is formed in the housing chamber 130 and communicates with the housing chamber 130. The upper space 131 is formed in the second partition wall 114b.

[0189] A lower space 132 is formed in the lower portion of the gear chamber 13 . The lower space 132 is partitioned into a chamber different from the accommodation chamber 130 .

[0190] The lower space 132 is formed below the upper space 131. The lower space 132 is formed between the motor chamber 12 and the accommodating chamber 130 of the gear chamber 13. The upper space 131 and the lower space 132 are separated by the upper and lower partition walls 114c extending rearward from the second partition wall 114b.

[0191] Furthermore, an upper space 131 and a lower space 132 are formed between the motor chamber 12 and the accommodation chamber 130 of the gear chamber 13 , and lubricating oil R3 is stored in both of them.

[0192] Thus, the upper space 131 and the lower space 132 can be provided while suppressing the increase in the upper and lower dimensions of the drive unit housing 11. Furthermore, 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 storage chamber 130 can be lowered, thereby further reducing the stirring resistance of the lubricating oil R3 generated by the rotation of the reduction gear 30.

[0193] The upper space 131 extends in the axial direction of the output rotating shaft of the reduction gear 30 , and is divided into a planetary-side upper reservoir 131 a and a differential-side upper reservoir 131 b in the axial direction of the output rotating shaft of the reduction gear 30 .

[0194] In this way, by forming the upper space 131 to be longer in the axial direction of the output rotating shaft of the reduction gear 30 and dividing it into a plurality of spaces in the axial direction of the output rotating shaft of the reduction gear 30, it is possible to extend the time for the lubricating oil R3 to stay in the upper space 131. Thus, it is possible to suppress the bubbling of the lubricating oil R3 and to cool the lubricating oil R3.

[0195] The upper space 131 , that is, the planetary-side upper reservoir 131 a and the differential-side upper reservoir 131 b are integrally formed with the drive unit case 11 (the left main case 114 in the present embodiment) by casting.

[0196] A part of the lubricating oil R3 that is brought up and scattered from the lower part of the accommodation chamber 130 by the planetary gear mechanism 31 is collected and stored in the planetary side upper storage portion 131 a .

[0197] Furthermore, a part of the lubricating oil R3 that is discharged and scattered radially outward from the input shaft 311 is collected and stored in the planetary-side upper reservoir 131 a .

[0198] Thus, by collecting the lubricating oil R3 that is discharged radially outward from the input shaft 311 and scattered, and the lubricating oil R3 that is carried and scattered by the planetary gear mechanism 31 by using the planetary upper storage portion 131a, the height of the liquid level of the lubricating oil R3 stored in the lower part of the storage chamber 130 can be further reduced, so that the stirring resistance of the lubricating oil R3 generated by the rotation of the reduction gear 30 can be further reduced. In this way, the height dimension of the drive unit 10 can be suppressed without reducing the power transmission efficiency.

[0199] A part of the lubricating oil R3 scattered by being dragged up 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 in the differential side upper reservoir 131 b.

[0200] Furthermore, a part of the lubricating oil R3 which is discharged from the right end of the input shaft 311 toward the differential gear mechanism 32 and is scattered by the rotation of the differential gear mechanism 32 is collected and stored in the differential-side upper reservoir 131 b.

[0201] Thus, by utilizing the upper storage portion 131b on the differential side to collect the lubricating oil R3 that is discharged from the right end portion of the input shaft 311 toward the differential gear mechanism 32 and scattered by the rotation of the differential gear mechanism 32, as well as the lubricating oil R3 that is brought up from the lower portion of the containing chamber 130 by the differential gear mechanism 32 including the differential case 321, the height of the liquid level of the lubricating oil R3 stored in the lower portion of the containing chamber 130 can be further reduced, thereby further reducing the stirring resistance of the lubricating oil R3 generated by the rotation of the reduction device 30.

[0202] In the left main case 114, the planetary side upper reservoir 131a and the differential side upper reservoir 131b are adjacent to each other via the upper partition wall 114d in the rotation axis direction of the planetary gear mechanism 31 and the differential gear mechanism 32. The upper partition wall 114d is provided with a first oil flow hole 134a that communicates the planetary side upper reservoir 131a and the differential side upper reservoir 131b, and allows the lubricating oil R3 to flow therethrough.

[0203] Thus, the lubricating oil R3 stored in the planetary-side upper reservoir 131 a can flow to the differential-side upper reservoir 131 b.

[0204] The left main housing 114 and the right main housing 115 are assembled by sandwiching a gasket 136. The gasket 136 is a plate-shaped member extending in the up-down direction and the front-rear direction. Moreover, the upper storage portion 131b on the differential side is formed on the left side of the gasket 136, and the wall portion of the upper storage portion 131b on the differential side is formed by the left main housing 114 and the gasket 136. Moreover, the gasket 136 forms at least a part of the right wall of the upper storage portion 131b on the differential side. On the right side of the gasket 136, an air permeable chamber 137 is formed in a manner adjacent to the upper storage portion 131b on the differential side via the gasket 136, and the wall portion of the air permeable chamber 137 is formed by the right main housing 115 and the gasket 136. Moreover, the gasket 136 forms at least a part of the left wall of the air permeable chamber 137.

[0205] Thus, the wall portion of the differential-side upper storage portion 131 b and the air permeable chamber 137 can be formed at low cost while suppressing an increase in weight.

[0206] The gasket 136 is provided with a communication hole 136a which connects the differential side upper reservoir 131b and the breathable chamber 137 and allows the gas in the differential side upper reservoir 131b and the breathable chamber 137 and the mist of the lubricating oil R3 to flow.

[0207] Thus, the communication hole 136 a that communicates the differential-side upper reservoir 131 b and the air permeable chamber 137 can be easily formed.

[0208] In addition, a vent hole 137a communicating with the outside of the drive unit housing 11 is provided at the upper portion of the vent chamber 137. When the pressure in the gear chamber 13 exceeds a predetermined pressure, gas is released from the vent hole 137a, and the pressure in the gear chamber 13 is maintained below the predetermined pressure.

[0209] In addition, the upper space 131 is connected to the chain chamber 14. For example, the upper space 131 may be connected to the chain chamber 14 by not having the baffle plate 116 above the upper space 131. In addition, for example, although the upper space 131 is separated from the chain chamber 14 by the baffle plate 116, a connecting hole connecting the upper space 131 and the chain chamber 14 may be provided in the baffle plate 116.

[0210] Therefore, if the pressure in the chain chamber 14 increases, the gas in the chain chamber 14 containing the mist lubricating oil R3 flows to the upper space 131. And, together with the gas in the gear chamber 13 containing the mist lubricating oil R3, it flows to the air permeable chamber 137 through the upper space 131. And, when the pressure in the gear chamber 13 exceeds the predetermined pressure, the gas is released from the air permeable hole 137a. Thus, the pressure in the chain chamber 14 is also maintained below the predetermined pressure together with the gear chamber 13.

[0211] Furthermore, when the pressure in the storage portion 622 exceeds a predetermined pressure, the gas containing the misty motor cooling oil R2 released from the air vent 112b to the chain chamber 14 flows from the chain chamber 14 through the upper space 131 to the air vent 137 together with the gas containing the misty lubricating oil R3 in the chain chamber 14. Furthermore, when the pressure in the gear chamber 13 exceeds a predetermined pressure, the gas is released from the air vent 137a.

[0212] Therefore, in order to maintain the storage part 622 below the specified pressure, the air chamber 137 and the air hole 137a of the lubricating oil R3 that lubricates the reduction gear 30 and the power transmission chain 40 are utilized. Therefore, there is no need to provide an additional air chamber and air hole in order to maintain the storage part 622 below the specified pressure, so that the drive unit 10 can be miniaturized.

[0213] Furthermore, by arranging the storage portion 622 at a position separated from the motor chamber 12 across the chain chamber 14, the storage portion 622 can be arranged at a position separated from the motor chamber 12 without increasing the size of the drive unit 10. Furthermore, by arranging the air permeable chamber 137 at a position adjacent to the accommodating chamber 130 and the motor chamber 12, the air permeable chamber 137 can be arranged by effectively utilizing the useless space generated between the accommodating chamber 130 and the motor chamber 12, thereby miniaturizing the drive unit 10.

[0214] Furthermore, since the storage portion 622 can be configured not to communicate directly with the outside of the drive unit 10 , it is possible to prevent foreign matter and moisture from entering the second temperature control circuit 62 from the outside of the drive unit 10 .

[0215] Above, one embodiment of the present invention has been described with reference to the accompanying drawings, but the present invention is certainly not limited to this embodiment. Obviously, those skilled in the art can think of various variations or modifications within the scope of the technical solution, and it should be understood that these variations and modifications also belong to the technical scope of the present invention. In addition, the various constituent elements in the above-mentioned embodiment can also be arbitrarily combined within the scope of the main purpose of the invention.

[0216] For example, in the present embodiment, the air chamber 137 and the air holes 137a are provided in the right main case 115, but may be provided in the left main case 114. In this case, the air chamber 137 may be provided instead of the differential-side upper reservoir 131b.

[0217] In the present embodiment, the air chamber 137 and the air holes 137 a are provided adjacent to the gear chamber 13 , but may be provided adjacent to the chain chamber 14 .

[0218] At least the following matters are described in this specification. In parentheses, corresponding components in the above-mentioned embodiment are shown as examples, but the present invention is not limited to these.

[0219] (1) A drive unit (drive unit 10), comprising:

[0220] a driving motor (driving motor 20 ) having a rotor (rotor 22 ) and a stator (stator 23 ); and

[0221] A drive unit housing (drive unit housing 11) having a motor chamber (motor chamber 12) for accommodating the drive motor.

[0222] in,

[0223] The stator includes a stator core (stator core 231) and a coil (coil 232) mounted on the stator core.

[0224] The drive unit housing is provided with:

[0225] a coolant introduction portion (oil introduction portion 126) for introducing coolant (motor cooling oil R2) into the motor chamber; and

[0226] a coolant discharge portion (oil discharge portion 127) for discharging the coolant from the motor chamber,

[0227] The stator is immersed in the coolant introduced into the motor chamber from the coolant introduction portion and is cooled by the coolant.

[0228] The coolant discharge portion is provided on a first wall portion (left wall portion 122) of the motor chamber facing in a horizontal direction.

[0229] A spacer (spacer 128) is provided between the coolant discharge portion and the stator in the axial direction of the drive motor in the motor chamber and at a position overlapping with the coolant discharge portion when viewed from the axial direction of the drive motor.

[0230] The spacer extends in the vertical direction so that the upper end portion (upper end portion 128a) is located higher than the upper end of the coil of the drive motor.

[0231] A communication space (communication space 125c) through which the coolant flows is formed between the upper end of the spacer and the drive unit housing.

[0232] The coolant flows in the communication space and is discharged from the coolant discharge portion to the outside of the motor chamber.

[0233] According to (1), the spacer allows the coolant to fill to a position higher than the upper end of the coil regardless of the position of the coolant discharge portion. Thus, in the motor chamber, even if the coolant discharge portion is set at a lower position, the entire coil can be reliably immersed in the coolant and cooled. Therefore, the coolant discharge portion can be set on the horizontal wall of the motor chamber without reducing the cooling efficiency of the coil, and the upper and lower dimensions of the drive unit housing can be made compact.

[0234] (2) The drive unit according to (1), wherein:

[0235] The coolant discharge portion is provided so that at least a portion thereof is located lower than the upper end portion of the spacer in the up-down direction.

[0236] According to (2), the coolant that flows from the communication space into the space on the coolant discharge portion side of the spacer over the upper end portion of the spacer can be more efficiently discharged to the outside of the motor chamber.

[0237] (3) The drive unit according to (1), wherein:

[0238] The coolant introduction portion is provided on a second wall portion (right wall portion 123 ) of the motor chamber that is opposite to the first wall portion.

[0239] According to (3), the coolant introduced into the motor chamber from the coolant introduction portion reliably flows from the second wall portion side to the first wall portion side of the motor chamber. As a result, the entire coil can be reliably immersed in the coolant and cooled.

[0240] (4) The drive unit according to (1), wherein:

[0241] The coolant inlet portion is disposed at a position lower than the coolant outlet portion.

[0242] According to (4), the coolant introduced into the motor chamber from the coolant introduction portion reliably flows in the vertical direction from the lower side to the upper side of the drive motor. As a result, the entire coil can be reliably immersed in the coolant and cooled.

[0243] (5) The drive unit according to (1), wherein:

[0244] The driving motor is arranged such that the rotation axis of the rotor faces in a horizontal direction.

[0245] According to (5), by arranging the drive motor so that the rotation axis of the rotor faces the horizontal direction, the space above and below the drive unit can be used more effectively.

[0246] (6) The drive unit according to (1), wherein:

[0247] A partition member (seal cover 24) extending along the inner peripheral surface of the stator is provided in the radial gap between the rotor and the stator.

[0248] In the motor chamber, the rotor is configured not to come into contact with the coolant.

[0249] According to (6), in the motor chamber, the partition member makes the rotor not contact the coolant, so the gap between the partition member and the outer peripheral surface of the rotor is not filled with coolant but becomes an air layer. Since the viscous resistance of air is lower than the viscous resistance of coolant, the presence of the air layer between the outer peripheral surface of the rotor and the inner peripheral surface of the stator can reduce energy loss when the drive motor is driven to rotate the rotor.

Claims

1. A drive unit comprising: a driving motor having a rotor and a stator; and a drive unit housing having a motor chamber for accommodating the drive motor, in, The stator comprises a stator core and a coil mounted on the stator core. The drive unit housing is provided with: a coolant introduction portion for introducing coolant into the motor chamber; and a coolant discharge portion for discharging the coolant from the motor chamber, The stator is immersed in the coolant introduced into the motor chamber from the coolant introduction portion and is cooled by the coolant. The coolant discharge portion is provided on a first wall portion of the motor chamber facing in a horizontal direction. A spacer is provided in the motor chamber between the coolant discharge portion and the stator in the axial direction of the drive motor and at a position overlapping with the coolant discharge portion when viewed from the axial direction of the drive motor. The spacer extends in the vertical direction so that the upper end portion is located higher than the upper end of the coil of the drive motor. A communication space for the coolant to flow is formed between the upper end of the spacer and the drive unit housing. The coolant flows in the communication space and is discharged from the coolant discharge portion to the outside of the motor chamber.

2. The drive unit according to claim 1, wherein: The coolant discharge portion is provided so that at least a portion thereof is located lower than the upper end portion of the spacer in the up-down direction.

3. The drive unit according to claim 1, wherein: The coolant introduction portion is provided on a second wall portion of the motor chamber that is opposite to the first wall portion.

4. The drive unit according to claim 1, wherein: The coolant inlet portion is disposed at a position lower than the coolant outlet portion.

5. The drive unit according to claim 1, wherein: The driving motor is arranged such that the rotation axis of the rotor faces in a horizontal direction.

6. The drive unit according to claim 1, wherein: A partition wall member extending along the inner peripheral surface of the stator is provided in a radial gap between the rotor and the stator. In the motor chamber, the rotor is configured not to come into contact with the coolant.

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