JP3084966B2 - Drive unit for electric 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 drive unit for an electric vehicle, and more particularly, to a drive unit incorporating a speed reducer.

[0002]

2. Description of the Related Art For an electric vehicle powered by a motor, extending the traveling distance per charge is the most important issue in practical use. For that purpose, the drive unit including the motor must be extremely lightweight and small. By the way, in terms of the layout of the whole vehicle, in particular, in order to secure a mounting space for the battery, it is effective means to configure the drive device coaxially with the axle. However, when adopting such a configuration, the outer diameter of the drive unit must be as small as possible to secure the minimum ground clearance, and it is difficult to obtain a sufficient driving force only by the motor torque under the regulation of the outer diameter. is there. From this point of view,
A drive unit combining a small-diameter motor with a reduction gear has been proposed.

[0003]

However, in the above-mentioned combination, a large driving force can be obtained with a small-diameter motor, but on the other hand, the axial length of the drive unit is increased, and the coaxial arrangement of the torque distribution device on the left and right wheels is also realized. In this case, it is difficult to accommodate between the left and right wheels.

In view of such circumstances, the present invention utilizes a dead space formed on the inner diameter side of a field coil end of a motor and arranges a speed reducer in the space, thereby increasing the shaft length. It is an object of the present invention to provide a drive unit for an electric vehicle that realizes a combination of a small motor and a speed reduction device without inducing.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention provides a motor including a rotor and a stator having a field coil projecting beyond the axial width of the rotor, and rotation of the rotor. A speed reducer having an input element, a reaction force element, and an output element for decelerating and amplifying torque, and connected to the rotor and the input element to distribute and transmit the rotational torque of the rotor to both left and right wheels of the vehicle. A torque distribution device disposed coaxially with the speed reduction device, and the motor;
A case for accommodating and supporting a reduction gear and a torque distribution device, wherein the reduction gear is disposed in a projecting portion inner diameter space of the field coil, and an output element of the reduction gear is rotatable to the case via a bearing. And the reaction force element of the speed reducer is radially outer side of the bearing.
It is arranged and supports the reaction force element on the outer peripheral side, and bears on the inner peripheral side.
It is turned around the case by a fixing member supported on the outer peripheral side of the ring.
And that it has been stopped . In the above configuration,
The fixing member keeps the bearing in the case.
It is even more effective if the
You.

[0006]

According to the present invention having such a configuration, a speed reduction device is disposed in a dead space formed on the inner diameter side of the field coil end of the motor, and the speed reduction device is disposed in the space. The reaction element of the output element supports the bearing
And placed on the outer periphery of the support bearing
By fixing to the case with the fixing member, it is possible to realize a drive unit in which the motor is combined with the reduction gear without substantially increasing the dimensions in the axial direction and the radial direction. Moreover, the support bearing of the output element
The configuration that supports the fixing member of the reaction force element with the outer diameter
Force element and output element directly on the inner and outer diameters of the support bearing
These are individually supported in the case because they are supported
The coaxiality of the output element and the reaction force element is improved compared to the configuration
And the assembling accuracy of the entire reduction gear can be improved.
You. In addition, the fixing member is supported and the bearing is prevented from falling out of the case.
When integrated with the retaining
This is advantageous in reducing the number of parts and improving the assemblability. Therefore, according to the present invention, it is possible to provide a drive unit for an electric vehicle that can be mounted between the wheels of a vehicle in a coaxial manner with a light-weight small-diameter motor as a drive source.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive unit according to the present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a partially expanded axial cross section of the embodiment, and FIG. 2 is a partially enlarged view thereof. The drive unit includes a pair of left and right motors 1a, 1a.
1b, a pair of left and right reduction gears 2a, 2b for decelerating their rotation and amplifying the torque, and both motors 1a, 1b for distributing and transmitting the rotational torque of the motors 1a, 1b to both left and right wheels of a vehicle (not shown). The two reduction gears 2a, 2b are connected to the reduction gears 2a, 2b, and are provided upstream of the two reduction gears 2a, 2b.
And a torque distribution device 3 arranged coaxially. Since the configuration and arrangement of the other pairs of components of the drive unit with respect to the torque distribution device 3 are substantially symmetrical, the left and right sides are distinguished from each other in the drawing unless otherwise required. Therefore, the description of the subscripted alphabetic symbols attached in the meaning of the following will be omitted, and the description of any one of them will be replaced with the description of both.

The motor 1 has a stator 1 having a rotor 14 and a field coil 13 projecting beyond its axial width.
And 1. The reduction gear transmission 2 has a planetary gear set 20 including an input element (a sun gear S in this example) for reducing the rotation of the rotor 14 and amplifying the torque, a reaction force element (also a ring gear R), and an output element (also a carrier CR). The torque distribution device 3 is connected to the rotor 14 and the input element S to be coaxial with the speed reducer 2 so as to distribute and transmit the rotational torque of the rotor 14 to both left and right wheels of the vehicle (not shown). The motor 1, the reduction gear 2, and the torque distribution device 3 are housed and supported in a drive device case 9. The reduction gear 2 is disposed in the projecting portion inner diameter space of the field coil 13, and the output element C of the reduction gear 2 is
R is located on the radially outer peripheral side of the bearing 64 and
Side supports the reaction force element CR, and the inner peripheral side
Non-rotating to the case by the flange 65 supported on the outer peripheral side
Have been

To explain the details of each part, the drive device case 9 has a pair of cylindrical center cases 91 each of which is open at both ends, and their opposite end faces are bolted together. Cup-shaped side cases 92 are respectively joined to the non-joining-side openings of both center cases 91 by means of soldering and bolted. In both center cases 91, partition walls 93 extending in the center direction from the peripheral walls are formed, and a differential device chamber 90 is defined between these partition walls, and the differential device 3 constituting the torque distribution device is accommodated therein.

The radial wall 9 of the partition 93 and the side case 92
4, a motor room 95 is defined, and the motor 1 is accommodated therein. The stator 11 of the motor 1 is fixed to the inner peripheral wall of the center case 91. That is, the stator 11 includes the armature core 12 and the field coil 13, and the armature core 12 has an inner end (hereinafter, referred to as both center cases 91) formed on a stepped portion 96 formed on the inner peripheral wall of the center case 91.
The inner and outer relationship will be described with the mating portion as the inner side), and the inner peripheral wall of the center case 91 is detently fitted and supported. On the other hand, the rotor 14 of the motor 1 has its rotor drum 15 supported by the differential device 3.

The differential device 3 includes a pair of differential cases 31 formed of a material having sufficient rigidity and bolted together, and a pinion shaft 30 and a pinion shaft 30 disposed at a joint thereof. A rotatable pinion 32,
It comprises a pair of side gears 33 that mesh with the pinion 32. The side gear 33 differentially transmits the rotation transmitted from the rotor 14 to the differential case 31 and transmits the rotation to a drive shaft 34 extending in the left-right direction of the vehicle.
The drive shaft 34 is in spline engagement with the end. The differential case 31 has a cylindrical portion 36 extending from the main body 35 to surround the drive shaft 34,
The rotor drum 14 is supported by the cylindrical portion 36.

The outer peripheral surface of the cylindrical portion 36 and the inner peripheral surface of the rotor drum 15 are spline-engaged. A bearing 61 is provided between the outer peripheral surface of the root portion of the cylindrical portion 36 and the partition wall 93. The differential device 3 is rotatably supported and positioned in the axial direction. And the cylindrical part 36
The drive shaft 34 is relatively rotatable while maintaining an appropriate amount of clearance between the inner and outer circumferences. Therefore, when the differential device 3 rotates differentially, the cylindrical portion 3
The drive shaft 34 rotates relative to 6. A parking gear 37b is formed on the outer periphery of the main body 35b of the one differential case 31b.

A thrust collar 38 is fitted near the outer end of the drive shaft 34 so as not to move in the axial direction.
A thrust bearing 62 is provided therebetween, and an outer end of the drive shaft 34 is in contact with an inner end of the transmission shaft 21 described later via the thrust bearing 63. Therefore, the drive shaft 34
The inward movement is prevented by the bearing 61 via the differential case 31 and the outward movement is prevented by the bearing 64 described later via the transmission shaft 21 and positioned.

On the outside of the thrust collar 38, that is, on the wheel side, a planetary gear set 20 constituting a reduction gear is disposed. The planetary gear set 20
A sun gear S, a pinion P meshing with the sun gear S, a carrier CR supporting the pinion P, and a ring gear R meshing with the pinion P; the sun gear S is formed integrally with the drive shaft 34;
It is bolted through 5. In this planetary gear set 20, rotation is input from the drive shaft 34 to the sun gear S, and reduced rotation is output from the carrier CR to the transmission shaft 21 and the flange yoke 5. Therefore, sun gear S forms an input element in planetary gear set 20, carrier CR forms an output element, and ring gear R forms a reaction force element.

On the outside of the carrier CR in the axial direction,
A transmission shaft 21 is continuously provided, and a flange yoke 5 which is rotatably supported by a side case 92 via a bearing 64 on the outer periphery of the transmission shaft 21 and takes power out of the drive unit case 9 is spline-fitted. The shaft 21 and the flange yoke 5 are axially positioned on the side case 92 by clamping the inner race 66 of the bearing 64 by nut tightening. Thus, the carrier CR is supported by the inner race 66 of the bearing 64 via the transmission shaft 21 integral with the carrier CR and the flange yoke 5 fitted on the outer periphery of the shaft.

On the other hand, on the outer side of the ring gear R in the axial direction, a flange 65 is engaged with an inner peripheral tooth of the ring gear R by engaging a spline portion on its outer periphery with a snap ring. The inner diameter of the flange 65 is a diameter that closely fits the outer diameter of the outer race 67 of the bearing 64, and a flange 68 that projects radially inward is formed at the inner end of the inner diameter portion. The flange 68 is fitted in a notched peripheral groove 69 formed at the innermost end on the outer periphery of the outer race 67. Flange 6
5 has bolt holes 70 formed in the axial direction along the circumference thereof (at an irregular pitch), and the bolt holes 70 are fastened to the side case 92 through fixing bolts 71. Thus, the outer race 67 is prevented from moving outward in the axial direction by the side case 92, and is prevented from moving inward by the flange 65. The ring gear R is prevented from moving outward in the axial direction by the outer ends of the inner peripheral teeth, is prevented from moving inward by the snap ring 72, and is centered and supported by the outer race 67.

In this drive unit, a lubricating device 4 is provided for lubricating various parts of the mechanism and for cooling the field coil 13 of the motor 1. It is arranged at the center in the direction. That is, in this example, the oil pump case 42 is provided in a chamber 97 which is connected to the differential device chamber 90 and is formed so as to protrude in front of the differential device chamber 90 (expanded upward in FIG. 1). The oil pump 40 is provided in the case 42. This oil pump 4
The zero pump gear 43 is driven by a gear 39 formed on the outer periphery of the main body 35 a of the differential case 31 via a drive gear 44. The oil discharged from the pump 40 is sequentially supplied from the supply unit 41 to each mechanism unit, and in addition to performing lubrication of each unit, is also supplied to the field coil 13 of the motor 1 from the oil passage 98, and cools the oil. The oil is collected in the oil reservoir below the center case 91.

In the drive unit configured as described above, when one or both of the two motors 1 are operated, the rotation of the rotors 14 is transmitted to the differential case 31 that is spline-engaged with them, and the rotation is transmitted to the differential device. 3 and is transmitted to the drive shaft 34 via the respective side gears 33. This rotation is performed by the two planetary gear sets 20.
, Is decelerated there and output from the carrier CR. The output rotation of the carrier CR is transmitted from the transmission shaft 21 via the flange yoke 5 to wheels (not shown) connected thereto. The vehicle runs by the rotation of the wheel.

In the drive unit according to the above embodiment,
The stopper 64 for supporting the carrier CR and the supporting member for supporting the ring gear R are integrated into one flange 65. Further, the bearing 64 is prevented from falling off on the inner peripheral side of the flange 65, and the ring gear R is fixed on the outer peripheral side. Because of the support structure, the flange 65 is accommodated within the axial width of the bearing 64 to avoid an increase in the axial dimension. This common use of members contributes to a reduction in the number of parts and an improvement in assemblability. In addition, the carrier CR shaft or the transmission shaft 21
The structure in which the support flange 64 of the ring gear R is directly supported by the outer diameter of the bearing 64 that supports the ring gear R results in a structure in which the ring gear R and the carrier CR are directly supported by the inner and outer diameter portions of the bearing 64. The coaxiality of the carrier shaft and the ring gear shaft is improved as compared with the configuration in which the planetary gear set is individually supported, and the
The overall assembly accuracy has been improved.

Although the embodiments of the present invention have been described in detail, it goes without saying that the present invention can be implemented by appropriately changing the specific configuration of each unit within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing a drive unit according to an embodiment of the present invention in a partially expanded sectional view.

FIG. 2 is a partially enlarged view of FIG.

[Explanation of symbols]

 Reference Signs List 1 motor 2 reduction gear 3 differential device (torque distribution device) 9 drive device case 11 stator 13 field coil 14 rotor 64 bearing 65 flange (fixed member) S sun gear (input element) R ring gear (reaction element) CR carrier (output) element)

Continuation of the front page (56) References JP-A 1-143446 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 17/00-17/26 F16H 57/00

Claims (2)

(57) [Claims] 1. A motor comprising a rotor and a stator having a field coil projecting beyond the axial width of the rotor, an input element, a reaction element and an output element for reducing the rotation of the rotor and amplifying the torque. And a torque distribution device connected to the rotor and the input element and disposed coaxially with the reduction device to distribute and transmit the rotational torque of the rotor to both left and right wheels of the vehicle, The motor,
A case for accommodating and supporting the speed reducer and the torque distribution device, wherein the speed reducer is disposed in a projecting portion inner diameter space of the field coil, and an output element of the speed reducer is rotatable to the case via a bearing. And the reaction force element of the speed reducer is radially outer side of the bearing.
It is arranged and supports the reaction force element on the outer peripheral side, and bears on the inner peripheral side.
It is turned around the case by a fixing member supported on the outer peripheral side of the ring.
A drive unit for an electric vehicle, which is secured. 2. The fixing member connects the bearing to a housing.
2. The device according to claim 1, wherein the device is integrated with a retaining member for retaining the component.
Drive unit for electric vehicles.