JP3218509B2 - Electric drive unit for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single electric motor, and the power of the electric motor is transmitted to left and right wheels of a vehicle .
A power transmission device arranged on one side of the electric motor ,
The present invention relates to a vehicle electric drive unit mainly applied to an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, as an electric drive unit of this kind, a casing of a power transmission device is constituted by a pair of first and second half portions divided into two right and left parts, as disclosed in Japanese Patent Application Laid-Open No. Hei 8-230489. An end piece portion of the motor housing of the electric motor is formed integrally with the first half portion, and the rotor shaft of the electric motor is inserted and supported by the first bearing mounted in the center hole of the end piece portion. , An input gear connected to the rotor shaft and concentric with the rotor shaft, and parallel to the input gear
A differential gear having a pair of left and right output shafts connecting the left and right wheels and a transmission mechanism connecting the input gear and the differential gear are housed in the gearbox. 2. Description of the Related Art There has been known an apparatus in which power is transmitted to left and right wheels via a gear.

In this case, a second casing is provided.
The other end of the input shaft, one end of which is rotatably supported by the second bearing mounted on the end wall of the half portion, is spline-fitted to the rotor shaft, and an input gear is formed at a portion near one end of the input shaft. The load acting on the bearing can be reduced.

[0004]

The electric drive unit comprises a mount bracket attached to the motor housing of the electric motor and a pair of mount brackets attached to the front and rear portions of the casing of the power transmission device. 3
It is designed to be mounted on the vehicle body at some places. The mounting bracket on the differential gear side of the pair of mounting brackets mounted on the casing is mounted on the first half, but when the input gear is formed near one end of the input shaft as in the above-described conventional example, the casing is It is necessary to reduce the height of the split surface of the first half (the distance from the first bearing to the split surface of the casing) in order to secure the rigidity balance of the components and the assemblability of the built-in components. Must be attached to the second half, and a pair of mounting brackets will be provided on both sides of the split surface of the casing. As a result, special measures for improving the tightening rigidity of the split surface of the casing and the durability of the split surface are required, which causes an increase in weight and cost.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an electric drive unit for a vehicle in which a load acting on a split surface of a casing is reduced to achieve weight reduction and cost reduction. .

[0006]

Means for Solving the Problems In order to solve the above problems,
The present invention provides a single electric motor and an electric motor disposed on one side of the electric motor that transmits the power of the electric motor to left and right wheels of the vehicle.
An electric drive unit for a vehicle, comprising: a power transmission device including a first and a second pair of left and right halves; An end piece portion of a motor housing of the motor is integrally formed, a rotor shaft of the electric motor is inserted and supported by a first bearing mounted in a center hole of the end piece portion, and connected to the rotor shaft in a casing. and the rotor shaft and the concentric input gear, input
A differential gear having a pair of left and right output shafts connecting the left and right wheels, and a transmission mechanism connecting the input gear and the differential gear, which are arranged in parallel to the power gear, are housed in the housing. When mounting a pair of mounting brackets on the rear part, the left-right direction is the axial direction, the electric motor side is the axial inside, the second half side of the casing is the axial outside,
With respect to the axial center position of the differential gear, the split surfaces of the two halves of the casing are axially outwardly offset, and the input gear is offset axially inward, respectively, in the center hole of the end piece portion, The first bearing is spaced axially inward from the first bearing,
An oil seal that defines an oil sump is mounted between the bearing and a bearing. Oil in the casing is supplied to the oil sump through an oil hole formed in the rotor shaft. The pair of mounting brackets are attached to the rear and the rear.

[0007] As described above, the split surface of the casing is offset axially outward with respect to the axial center position of the differential gear, and the input gear is offset axially inward, so that the left and right sides of the casing can be offset. The split surface height of the first half can be increased without destroying the rigidity balance of
Therefore, the mounting space for the mounting bracket is secured in the first half, and both the front and rear mounting brackets can be mounted on the first half. As a result, the mount reaction force from the mount bracket is not input to the split surface of the casing, and the load acting on the split surface is reduced.
Thus, a special measure for improving the tightening rigidity of the split surface of the casing and the durability of the split surface becomes unnecessary, and the weight and cost can be reduced.

According to the present invention, since the input gear is disposed near the first bearing, the load on the first bearing increases. However, as described above, the oil supplied from the oil hole of the rotor shaft to the oil sump is provided. Thereby, the first bearing is efficiently lubricated, and the durability of the first bearing is not impaired.

The input gear may be cantilevered by the first bearing via the rotor shaft. However, the input gear is integrally formed with a gear shaft extending outward in the axial direction, and the end of the second half is formed. When the second bearing is mounted in the recess formed in the inner surface of the wall and the end of the gear shaft is supported by the second bearing, the input gear is supported at both ends by the first bearing and the second bearing. This is advantageous because the support rigidity of the gear can be improved. In this case, it is desired to make the gear shaft hollow and supply oil to the oil hole of the rotor shaft through the inside of the gear shaft.

In order to efficiently supply the scraping oil in the casing into the gear shaft, it is necessary to introduce the oil from above into the gap between the end face of the recess and the second bearing. In this case, a vertical hole reaching the gap from the upper surface of the second half and a horizontal hole extending inward in the axial direction from the vertical hole are formed in the upper peripheral wall of the concave, and the upper surface of the second half is formed. It is conceivable that the open end of the vertical hole is closed with a blind plug and oil in the casing is guided to the gap through the horizontal hole and the vertical hole. But
In this case, the vertical hole must be formed by machining, and a blind plug is required, which increases the cost.

When it is necessary to make the second bearing insertable into and removable from the concave hole in order to enable the assembly and disassembly of the casing, the second bearing is axially locked in the concave hole by a circlip. And the circlip operating on the inner surface of the recess extending axially from the outer surface of the end wall of the second half to the engagement portion of the circlip on the peripheral wall of the recess. A hole may be formed so that a tool can be inserted into the maintenance hole to release the engagement of the second bearing by the circlip. Here, the maintenance hole is formed on the upper peripheral wall of the concave hole so as to face the upper inner surface of the concave hole, and a communication hole extending inward in the axial direction from the maintenance hole to the peripheral wall portion and communicating with the space in the casing. If the opening end of the maintenance hole on the outer surface of the end wall portion of the second half is closed with a detachable maintenance plug, the oil in the casing is transferred to the gap from above through the communication hole and the maintenance hole. I can guide you. According to this, processing of the vertical hole becomes unnecessary, and a blind plug for the vertical hole becomes unnecessary, so that cost can be reduced.

By the way, in order to secure a wide crushable zone at the front and rear of the vehicle, it is desirable to dispose a power control unit below the floor of the vehicle in addition to the battery for the electric motor. In this case, the power control unit is disposed inside the vehicle length direction with respect to the front wheels and the rear wheels. In this case, the electric motor is arranged to be offset inward in the vehicle length direction with respect to the differential gear, and the end piece portion is provided inward of the first half of the pair of mount brackets in the vehicle length direction. Aside from one of the mounting brackets attached to the part facing
By providing the terminal of the electric motor, the length of the high-voltage cable used for wiring between the terminal and the power control unit can be reduced, the number of high-voltage cable wiring clips used can be eliminated, and power loss due to resistance can be reduced. And the cost and the weight of the vehicle can be reduced. Further, the one mount bracket functions as a protector for preventing foreign matter such as gravel flying from the outside from colliding with the terminal portion, and a dedicated protector for protecting the terminal portion is not required, thereby reducing costs.

[0013]

FIG. 1 shows a front-wheel drive electric vehicle. An electric drive unit PU comprising an electric motor 1 and a power transmission device 2 for transmitting the power of the electric motor 1 to left and right front wheels W is shown in FIG. A battery BAT and a power control unit CU positioned in front of the battery BAT are arranged below the floor of the vehicle body, and the battery BAT is connected to the power control unit CU and the high-voltage cable 3 from the battery BAT. Electric power is supplied to the electric motor 1 via the electric motor 1. The electric motor 1 is composed of a three-phase AC motor, and three high-voltage cables 3 are connected to the electric motor 1. As shown in FIG. 2, the power transmission device 2 includes a rotor shaft 10 of the electric motor 1 in a casing 20 including a first and a second pair of halves 201 and 202 that are divided into two right and left parts.
Gear 21 and a pair of left and right output shafts 22
0 and 220, and a transmission mechanism 23 for connecting the input gear 21 and the differential gear 22. The output shaft 220 of the differential gear 22 has left and right front wheels. Are connected via a constant velocity joint 221.

The casing 20 includes a first half 201 on the right side.
As shown in FIG. 3, the second half portion 202 on the left side is assembled by positioning with a dowel pin 20a and fastening with a plurality of bolts 20b. The main body 1 of the motor housing 11 of the electric motor 1 is provided on an end wall of the first half 201.
An end piece 111 of the motor housing 11 for fastening the motor 10 with a plurality of bolts 11a is integrally formed,
The first attached to the center hole 111a of the end piece 111
The rotor shaft 10 is inserted and supported by the bearing 24. The first
The bearing 24 is restrained in the axial direction by a holding plate 24a.

The differential gear 22 includes a pair of left and right output shafts 22.
0 and 220, a pair of left and right side gears 223 and 223, which are bevel gears spline-fitted to both output shafts 220 and 220, respectively, and umbrellas meshing with both side gears 223 and 223. It is constituted by a well-known bevel gear type differential gear provided with a plurality of pinions 224 formed of gears. The differential case 222 is rotatably supported in the casing 20 via bearings 225 and 225 at both left and right ends, and the power input through a final gear 226 attached to the outer periphery of the differential case 222 is used for the left and right output shafts. 22
0,220.

The transmission mechanism 23 comprises a large-diameter first reduction gear 230 meshing with the input gear 21 and a small-diameter second reduction gear 231 meshing with the final gear 226,
0, a reduction gear mechanism provided on a common intermediate shaft 233 that is supported via bearings 232 and 232 at both left and right ends, and the power of the electric motor 1 is transmitted from the input gear 21 to the differential gear 22. To reduce the transmission. Also, the intermediate shaft 233
, A parking gear 234 is provided between the first and second reduction gears 230 and 231.

The electric drive unit PU includes a casing 20
A pair of mount brackets 4 and 5 attached to the front and rear portions of the vehicle and a mount bracket (not shown) attached to the motor housing 11 are attached to the vehicle body via mount members MT. In this case, in order to shorten the length of the high-voltage cable 3 by bringing the electric motor 1 closer to the power control unit CU disposed inward in the vehicle length direction than the axle, a differential gear disposed substantially coaxially with the axle. The electric motor 1 is arranged to be offset inward in the vehicle length direction with respect to 22. That is, when the front wheels are connected to the differential gear 22 as in the present embodiment, the electric motor 1 is arranged offset to the rear with respect to the differential gear 22, and when the rear wheels are connected to the differential gear 22, The electric motor 1 is arranged to be offset forward with respect to the differential gear 22.

Here, the left-right direction is the axial direction, and the electric motor 1
Side, that is, the right side is inward in the axial direction, and the second half portion 202 side of the casing 20, that is, the left side is axially outward, and the split surface 20 of the first and second half portions 201 and 202 of the casing 20 is
c is offset axially outward with respect to the axial center position of the differential gear 22, and the input gear 21 is offset axially inward with respect to the axial center position of the differential gear 22. The rotor shaft 10 is disposed so as to fit around the end of the rotor shaft 10. According to this, the split surface height h of the first half part 201 can be increased without breaking the rigidity balance between the left and right of the casing 20, and a mounting space for the mount bracket can be secured in the first half part 201. Thus, the mounting brackets 4 and 5 on the front and rear of the casing 20 are both attached to the first half 201, and the casing 20 can be stably supported. Then, the front and rear brackets 4 and 5 are both attached to the first half 2
01, the split surface 20 of the casing 20
The mount reaction force from the mount brackets 4 and 5 is no longer input to c, and the load acting on the split surface 20c is reduced. Thus, the two halves 201, 202 on the split surface 20c
This eliminates the need for a special measure to improve the tightening rigidity and durability of the split surface 20c, and can reduce the weight and cost.

In the present embodiment, in order to reduce the length of the high-voltage cable 3 as much as possible, the end piece 111 of the motor housing 11 formed in the first half 201 is provided inward in the vehicle length direction, ie, , A rearward projecting portion, and a terminal portion 11 for connecting the high-voltage cable 3 to the projecting portion.
2 are provided. By attaching the mount bracket 5 provided on the first half part 201 to the portion of the casing 20 facing inward in the vehicle length direction, that is, the rear portion, the terminal portion 112 can be disposed adjacent to the mount bracket 5 in the lateral direction. According to this, the mount bracket 5 functions as a protector that prevents foreign matter such as gravel flying from the outside from hitting the terminal portion 112. Thus,
A dedicated protector for protecting the terminal unit 112 is not required, and the cost can be further reduced. 112a in the figure
Is a terminal cover attached to the maintenance opening of the terminal section 112.

When the input gear 21 is offset inward in the axial direction, the load on the first bearing 24 increases.
It is necessary to improve the lubricity of the bearing 24. Therefore, in the present embodiment, the center hole 1 of the end piece portion 111
An oil seal 26 that defines an oil reservoir 25 between the first bearing 24 and the first bearing 24 is attached to the first bearing 24 in an axially inward direction with respect to the first bearing 24. Forming an oil hole comprising a shaft hole 10a and a radial through hole 10b communicating the shaft hole 10a with the oil sump 25;
The oil scooped up in the casing 20 is guided to the shaft hole 10a by a path described later, and is passed through the through-hole 10b.
The oil is efficiently supplied to the first bearing 24 via the.

The input gear 21 may be cantilevered by the first bearing 24 via the rotor shaft 10, but in this embodiment, the input gear 21 is a hollow gear shaft 2 extending axially outward.
1a is integrally formed, and the second bearing 27 is attached to a concave hole 202a formed in the inner surface of the end wall of the second half portion 202 of the casing 20, and the end of the gear shaft 21a is fitted to the second bearing 27. The first gear 24 and the second bearing 27 support the input gear 2
1 is supported at both ends. Further, a hollow connection shaft 28 is provided in the gear shaft 21a, and the axially inner end of the connection shaft 28 is spline-fitted to the inner circumference of the end of the rotor shaft 10, and the axially outer end of the connection shaft 28 is geared. The input gear 21 is connected to the rotor shaft 10 via a connection shaft 28 by spline-fitting the inner periphery of the end of the shaft 21a. Note that the input gear 21 is spline-fitted to the outer periphery of the end of the rotor shaft 10 so that the connection shaft 28
May be omitted.

The second bearing 27 includes a thrust bearing 27
0 and a radial bearing 271 are arranged in two axially adjacent bearings. The second bearing 27 is axially locked by a circlip 27a that engages with the groove on the outer peripheral surface of the radial bearing 271 and the groove on the inner surface of the concave hole 202a. Here, the second half 20
2 is removed from the first half 201, the input gear 21
If the second gear 202 is locked in the axial direction with respect to the second half 202 via the bearing 27, the input gear 21 is hooked on the parking gear 234. It is necessary to release the engagement of the bearing 27 and separate the second bearing 27 from the concave hole 202a.

Therefore, in the present embodiment, as shown in FIGS. 4 and 5, the second half 2 is formed on the upper peripheral wall of the concave hole 202a.
A maintenance hole 202b extending in the axial direction from the outer surface of the end wall portion 02 to the engagement portion of the circlip 27a and facing the upper inner surface of the concave hole 202a is formed. Then, the detachable maintenance plug 202c for closing the opening end of the maintenance hole 202b on the outer surface of the end wall portion of the second half portion 202 is removed, and an appropriate tool inserted into the maintenance hole 202b from the opening end is used to join the circlip 27a. The engagement of the second bearing 27 can be released by expanding the portion.

Further, in the present embodiment, the communication hole 20 extending inward in the axial direction from the maintenance hole 202b and penetrating into the space in the casing 20 is formed in the peripheral wall above the concave hole 202a.
2d, and a gutter-shaped oil pocket member 202e extending to an axial position where the parking gear 234 is disposed is attached to an axially inward end face of the peripheral wall portion, and a second bearing 27 is provided in the concave hole 202a. An oil guide 202f that covers the oil hole 202 from the outside in the axial direction is mounted with a gap between the oil guide 202f and the end surface of the concave hole 202a. Here, maintenance hole 2
02b faces the upper inner surface of the recess 202a.
The maintenance hole 202b communicates with the upper portion of the gap between the end face of the oil guide 2f and the oil guide 202f.
Thus, the oil scooped up by the parking gear 234 flows into the concave hole 202a from above through the oil pocket member 202e, the communication hole 202d, and the maintenance hole 202b.
Is supplied to the gap between the end face of the oil guide 202f and the oil guide 202f, the oil is guided from the gap to the shaft hole 10a of the rotor shaft 10 through the connection shaft 28 in the gear shaft 21a, and the oil is centrifugally transmitted through the through hole 10b. Oil is supplied to the reservoir 25, and the first bearing 24 is efficiently lubricated.

In order to prevent fretting wear of the spline portions at both ends of the connecting shaft 28 and the fitting portion between the rotor shaft 10 and the first bearing 24, radial holes 28a are formed in the connecting shaft 28.
To supply oil to the spline portion via a gap between the outer peripheral surface of the connecting shaft 28 and the inner peripheral surface of the gear shaft 21a, and to the rotor shaft 10 and the fitting portion of the first bearing 24. A matching radial through hole 10c is formed to supply oil to the fitting portion.

Although the electric drive unit PU mounted on the electric vehicle has been described above, the present invention is similarly applied to an electric drive unit mounted on a hybrid vehicle in which one of the front and rear wheels is driven by an engine and the other is driven by an electric motor. Can be applied.

[0027]

As is apparent from the above description, according to the present invention, the lubricating property of the first bearing mounted on the end piece of the motor housing integrated with the first half of the casing can be improved. The gear is arranged near the first bearing,
First without losing the right and left rigidity balance of the casing
The height of the split surface of the half can be increased, so that both the front and rear mounting brackets can be attached to the first half to reduce the load acting on the split surface of the casing. Special measures for improving the tightening rigidity and durability of the surface are not required, and the weight and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a vehicle equipped with a unit of the present invention.

FIG. 2 is a cutaway plan view of an example of the unit of the present invention.

FIG. 3 is a side view cut along the line III-III of FIG. 2;

FIG. 4 is an inner side view of a main part of the second half with the second bearing removed;

5 is a sectional view taken along the line VV of FIG. 4 with a second bearing mounted.

[Explanation of symbols]

PU Electric drive unit 1 Electric motor 10 Rotor shaft 10a, 10b Oil hole 11 Motor housing 111 End piece 111a Center hole 112 Terminal 2 Power transmission device 20 Casing 20c Split surface 201 First
Half part 202 Second half part 202a Recessed hole 202b Maintenance hole 202c Maintenance plug 202d Communication hole 21 Input gear 21a Gear shaft 22 Differential gear 23 Transmission mechanism 24 First bearing 25 Oil reservoir 26 Oil seal 27 Second bearing 27a Circlip 4 , 5 Mounting bracket

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-300993 (JP, A) JP-A-6-87336 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 17/04 F16H 57/02 531 F16H 57/04

Claims (3)

(57) [Claims] A single electric motor and one side of the electric motor for transmitting the power of the electric motor to left and right wheels of the vehicle.
An electric drive unit for a vehicle, comprising: a power transmission device mounted on the vehicle; and a casing of the power transmission device comprising a pair of first and second halves that are divided into two right and left parts. The end piece part of the motor housing of the electric motor is formed integrally,
The rotor shaft of the electric motor to the first bearing mounted in the center hole of the end-piece portion is inserted axially supported, in a casing, is connected to the rotor shaft, the rotor shaft and the concentric input gear, input gear
And a differential gear having a pair of left and right output shafts connecting the left and right wheels, and a transmission mechanism connecting the input gear and the differential gear. A pair of mounting brackets is attached to the differential gear, wherein the left-right direction is the axial direction, the electric motor side is the axially inner side, and the second half side of the casing is the axially outer side. On the other hand, the split surfaces of the two halves of the casing are offset axially outward and the input gear is offset axially inward, respectively, and the center hole of the end piece portion is axially inward with respect to the first bearing. And an oil seal that defines an oil sump between the first bearing and the first bearing. The oil inside the casing is supplied to the oil sump through an oil hole formed in the rotor shaft. The front part of the first half Wherein on the part mounting a pair of mounting brackets, a vehicle electric drive unit, characterized in that. 2. A hollow gear shaft extending outward in the axial direction is integrally formed with the input gear, and an end of the gear shaft is supported by a recess formed in an inner surface of an end wall of a second half of the casing. The second bearing is axially locked by a circlip and mounted on the peripheral wall on the upper side of the recess from the outer surface of the end wall of the second half to the locked position of the circlip. A maintenance hole for circlip operation that faces the upper inner surface of the concave hole, and a communication hole that extends inward in the axial direction from the maintenance hole and communicates with the space in the casing; The opening end of the maintenance hole on the outer surface of the wall is closed with a detachable maintenance plug, and the oil in the casing is filled with the communication hole, the maintenance hole, the gap between the end surface of the concave hole and the second bearing, and the gear. And supplying the oil to the oil hole of the rotor shaft through the inside of the shaft. Vehicle electric drive unit of claim 1 that. 3. The vehicle according to claim 1, wherein the electric motor is offset inward in the vehicle length direction with respect to the differential gear, and the end piece portion has a first half portion of the pair of mounting brackets in the vehicle length direction. The electric drive unit for a vehicle according to claim 1 or 2, wherein a terminal portion of the electric motor is provided adjacent to an inner side in the axial direction of one of the mount brackets attached to the portion facing inward.