JPH08332855A - Power unit of electric vehicle - Google Patents

Abstract

PURPOSE: To provide the power unit of an electric vehicle to reduce a cost and have sufficient rigidity. CONSTITUTION: The power unit of an electric vehicle wherein an electric motor 46 and a differential gear 47 and loaded on a subframe 37 and a drive wheel 48 mounted on the output shaft of the electric motor 36 and a driven wheel 49 mounted on the input shaft of a differential gear 47 are intercoupled through a transmission 50. The case 47b of the differential gear 47 is fixed to a subframe 37, a support bracket 51 is arranged between the electric motor 46 and the drive wheel 48. The support bracket 51 is fixed to the subframe 7, the end face on the drive wheel side of an electric motor 46 is fixed to the support bracket 51, the support bracket 51 is extended to the differential gear 47 side, and an extension part 51b is fixed on the end face on the driven wheel side of the differential gear case 47b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power unit for an electric vehicle in which an electric motor and a differential device are mounted on a subframe.

[0002]

2. Description of the Related Art Recently, an electric vehicle having a power unit composed of an electric motor and a differential gear has been proposed. As the power unit in an electric vehicle of this type, there is one in which the electric motor, the differential device, and the power transmission mechanism are housed and arranged in a common casing integrally cast (for example, JP-A-5-161221). reference).

[0003]

The above-mentioned conventional power unit has an advantage in that the power unit as a whole can be made highly rigid because the electric motor, the differential device, etc. are housed and arranged in the integrally cast casing. However, the cost is high because a large-scale casting die is required.

In order to avoid the problem of high cost, it is advantageous to mount the electric motor and the differential gear on a common subframe made of steel, for example, and connect them by a transmission belt such as a V-belt. Is. However, in the case of this structure, a support structure that can cope with a large tilting force that acts on the electric motor or the like due to high torque is required.

The present invention has been made in view of the above conventional circumstances, and an object thereof is to provide a power unit for an electric vehicle that is low in cost and has sufficient rigidity.

[0006]

According to the present invention, an electric motor and a differential gear are mounted on a sub-frame, and a drive wheel mounted on an output shaft of the electric motor and an input shaft of the differential gear are mounted. In a power unit of an electric vehicle in which driven wheels are connected to each other by a transmission member, the case of the differential device is fixed to the subframe, and a support bracket is arranged between the electric motor and the drive wheel. Is fixed to the sub-frame, the end face of the electric motor on the drive wheel side is fixed to the support bracket, the support bracket is extended to the differential device side, and the extension portion is attached to the differential device case. It is characterized by being fixed to the end face on the driving wheel side.

In the present invention, the driving wheel and the driven wheel include a pulley, a sprocket, a gear, and the like, and the transmission member includes a V belt, a chain, an idle gear, and the like.
Further, the differential device in the present invention also includes one having a transmission mechanism incorporated therein.

[0008]

According to the present invention, since the drive wheel side end surface of the electric motor is fixed to the support bracket fixed on the sub-frame, that is, the portion close to the drive wheel on which the large torque acts is supported by the bracket. The large torque increases the supporting force of the bending moment acting on the electric motor, and prevents the motor from falling.

Further, since the support bracket is extended and the extension bracket is fixed to the differential device which is firmly connected and fixed to the subframe, the differential device itself functions as a reinforcing member. Also, the supporting force for the bending moment is further increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 7 are views for explaining an electric vehicle according to an embodiment of the present invention, and FIGS. 1 and 2 are a left side view, a plan view, FIG. 3, FIG. 4, and FIG. Are left side views, plan views and front views of the front part of the vehicle body, and FIGS. 6 and 7 are left side views and plan views of the rear part of the vehicle body.

In the figure, reference numeral 1 is an electric vehicle, which has left and right front wheels 3 and 3 disposed on the left and right of a front portion of a chassis (body frame) via a front wheel suspension device 4 and left and right portions of a rear portion. The right rear wheel 5 is arranged via a rear wheel suspension device 6, and a resin body 7 is mounted on the upper side of the chassis 2.

The chassis 2 has a pair of side frames 8 arranged on the left and right outer sides, and a pair of left and right center frames 9 arranged between the side frames, which will be described later. It has a schematic structure in which a large number of cross frames are connected.

The side frames 8 have front and rear wheels 3, 3, respectively.
Lower side frame 8a located near the axle height between 5
Weld the front end of the upper side frame 8b in the middle of
It has a structure in which the upper side frame 8b extends obliquely above the rear wheel 5 and covers the rear wheel 5. The left and right lower side frames 8a, 8a have front portions, central portions, and rear end portions connected and fixed by front, central, and rear cross frames 10a, 10b, 10c, respectively. The rear ends of 8b and 8b are connected and fixed by a cross frame 10d at the upper rear end.

The left and right center frames 9 and 9 extend forward from the central cross frame 10b horizontally.
After leaning slightly diagonally upward near the front wheels, it extends forward beyond the front wheel axis. The rear portions of the center frames 9 and 9 are connected and fixed to the side frames 8 and 8 via the central portion and the front cross frames 10b and 10a, and the front wheel inner portions of the center frame 9 are cross frames between front wheels. The front ends of the front extension portions 9a, 9a of the center frames 9, 9 are connected and fixed by front end cross plates 10g. As a result, the front extension portions 9a, 9a have sufficient rigidity to bear the longitudinal force acting on the strut bar 19, which will be described later.

The left and right lower side frames 8,
At the front end portion of the door 8, door support frames 13, 13 that support a door 16 in the form of a pipe ladder are erected. The upper portions of the door support frame 13 are connected to each other by a cross frame 14 having an inverted U-shape in a plan view, and a vertical frame 15 is erected between the cross frame 14 and the center frames 9, 9.

Lower cross frames 10a and 10b at the central and rear end portions and lower side frames 8a on the left and right sides,
A battery case 11 shaped like a saucer is disposed in the portion surrounded by 8b.
Four batteries 12a are mounted on the top in parallel in the vehicle width direction. The seat 1 is provided above the battery 12a.
7 are provided.

Front extension 9 of the center frames 9, 9
A battery case 18 shaped like a saucer is disposed in a portion surrounded by a, 9a, the front end cross plate 10g and the front wheel cross frame 10f, and two batteries 12b are provided on the battery case 18. Is installed.

A support bracket 20 is disposed and fixed near the center of the lower surface of the front end cross plate 10g in the vehicle width direction. A rubber damper 21 formed at the front end of a strut bar (front-rear force member) 19 of the front wheel suspension device 4 is connected to the bracket 20.
9 is rotatable around the axis of the strut bar 21 due to the elasticity of the rubber damper 21, and can withstand the axial load.

The rear end of the strut bar 19 is welded to a portion of the suspension arm 22 supporting the front wheel 3 in the vicinity of the front wheel 3. The strut bar 19 is capable of counteracting the longitudinal force acting on the front wheel suspension device 4. A steering tie rod 24 is connected to an arm portion 23b of a knuckle 23 to which the suspension arm 22 is connected, and a strut-type front cushion 25 is fixed to a support portion 23a. The front cushion 25 is formed by arranging a coil spring 25b around a shock absorber 25a composed of a cylinder and a piston. The lower end of the shock absorber 25a is supported and fixed to the support portion 23a. The upper end of is supported and fixed to the upper end of the strut tower 26 by a bracket 26a formed so as to project in the vehicle width direction.

The left and right strut towers 26, 26
Is fixed to the front extension 9a and extends substantially vertically upward,
The upper ends thereof are connected and fixed by a tower bar 27 extending substantially horizontally in the vehicle width direction. A cylinder main body 28a of the brake master cylinder 28 is located on the lower right side in the vehicle width direction of the tower bar 27 and behind the front edge of the tower bar 27.
The reserve tank 28b for supplying hydraulic oil to the cylinder body 28a is located on the upper surface of the tower bar 27 and behind the front edge. A brake pedal 29 operates the brake master cylinder 28.

A gear box 31 connected to the lower end of the steering shaft 30 is disposed below the center of the tower bar 27 and behind the front edge of the tower bar 27.
The output shaft 31a of the gear box 31 is connected to the tie rod 24 via a pitman arm 31b.

Further, a support plate 32 is welded and fixed to the upper surface on the left side in the vehicle width direction of the tower bar 27.
An accelerator converter 34 for converting the depression amount of the accelerator pedal 33 into an electric signal is mounted on the support plate 32, and the front edge of the accelerator converter 34 is located behind the front edge of the tower bar 27. Is located in. 3
An accelerator cable 4a connects the accelerator pedal 33 and the accelerator converter 34, and the cable 34a
Thus, the depression amount of the accelerator pedal 33 is transmitted to the accelerator converter 34.

Below the accelerator converter 34,
The battery 12 is connected to an external AC power source.
A charger 35 for charging a and 12b is provided. The charger 35 includes a cross frame 10g inside the front wheel,
It is arranged and fixed on a support bracket 35a fixed to 10f, and its front edge is located rearward of the front edge of the tower bar 27.

The rear wheel suspension system 6 includes a power unit 36.
Is connected to the rear cross frame 10c of the chassis 2 so as to be vertically swingable and rotatable left and right, and is attached to both ends of an axle case 38 fixed to the sub frame 37 and having an axle 60 therein. Arrange the wheel 5,
A rear cushion 39 is arranged between the sub-frame 37 and the upper side frame 8b of the chassis 2 to have a schematic structure.

In the sub-frame 37, round steel pipes 37a are combined in a trapezoidal shape in plan view and welded to each other, and a cross angle 37b having an L-shaped cross section extending in the vehicle width direction is welded and fixed to the approximate center in the front-rear direction thereof. Support tube 3 in the widthwise central part
7c is welded and fixed so as to project forward.

A rubber damper 40 is fixed to the tip of the support tube 37c, and the rubber damper 40 is connected to a bracket 41a fixed to the cross frame 10c by a bolt 42 inserted in the vehicle width direction. The rubber damper 40 has a rubber member 40c inserted and fixed between an outer cylinder 40a and an inner cylinder 40b.
Is supported so as to be swingable around the bolt 42 and rotatable about the axis of the support tube 37c by the elasticity of rubber.

The axle case 38 is bolted and fixed to the pedestals 37d and 37d of the sub-frame 37 via a pair of left and right brackets 43 and 43. A link support portion 43a and a cushion support portion 43b are formed on the front and rear sides of the axle case 38 of the bracket 43, respectively.

A rear end rubber damper 44a of a suspension link (front and rear drag member) 44 is connected to the link support portion 43a by a bolt 45a, and a front end rubber damper 44b of the suspension link 44 is bolt 45b.
It is connected to a bracket 41b formed on c. The suspension link 44 is rotatable around the bolts 45a and 45b, and is rotatable about the axis of the suspension link 44 within the elastic range of the rubber member. The shaft center of the rear end rubber damper 44a is located higher than the shaft center of the rear wheel shaft 60, and the shaft center of the front end rubber damper 44b and the shaft center of the rubber damper 40 are located on the same straight line. Furthermore, when the vehicle is stationary, the front end rubber damper 44b is located lower than the rear end rubber damper 44a, so that the suspension link 44 is lowered frontward.

A lower end portion of a shock absorber 39a of a rear cushion 39 is swingably connected to the cushion support portion 43b around a bolt 45c, and an upper end portion of the rear cushion 39 is connected to the upper side frame 8 described above.
A cushion bracket 8c formed so as to project inward from b is swingably connected around a bolt 45d.

The power unit 36 includes an electric motor 46.
And a differential device 47. The drive pulley 48 mounted on the output shaft 46a of the electric motor 46 and the differential device 4
7 and the driven pulley 49 mounted on the input shaft 47a
The belt 50 is wound. The drive pulley 4
8. The driven pulley 49 is configured such that the diameter of the drive pulley increases due to centrifugal force as the rotation speed of the electric motor 46 increases, and the diameter of the driven pulley decreases accordingly.

The differential device 47 is formed by integrating an input case 47b supporting the input shaft 47a and a differential case 47c containing a differential gear mechanism. The inner ends of the axle case 38 are bolted and fixed to the left and right sides of the differential case 47c via a flange 38a,
In this way, the differential device 47 is firmly fixed to the sub frame 37 via the axle case 38 and the bracket 43.

A bracket 51 is fixed to the end surface of the electric motor 46 on the side of the drive pulley 48 by a bolt 52a, and a flange portion 51a bent outward at the lower end of the bracket 51 is sub-shaped by a bolt 52b. It is fixed to the frame 37. The rear end portion of the bracket 51 is extended to the differential device 47 side, and the extension portion 51b is fixed to the pulley-side end surface of the input case 47b with a bolt 52c. Reference numeral 51c is a distance piece for filling a gap between the extension 51b and the end surface of the input case 47b, and is welded and fixed to the inner surface of the extension 51b.

The input case 47a of the differential device 47 is also provided.
A left-right extension bracket 53 extending outward in the vehicle width direction is fastened and fixed to the end face on the side opposite to the pulley by bolts 53a. A right end rubber damper 54a of a lateral rod (right and left reaction member) 54 is swingably connected around a bolt 55a at the tip of the left and right extension bracket 53. The lateral rod 54 is arranged so as to extend substantially horizontally in the vehicle width direction at a height near the axis of the driven pulley 49, and the left end rubber damper 54b is provided at the lower end portion of a vertically extending bracket 56 extending vertically. It is swingably connected around the bolt 55b. The upper end of the vertical extension bracket 56 is welded and fixed to the cross frame 10d at the rear end.

The front portions of the cushion brackets 8c of the upper side frames 8b, 8b are connected and fixed by a cross frame 57. This cross frame 57
Is a saucer-like one formed by connecting the front and rear two L-shaped frame members 57a with the left and right two strip-shaped reinforcing members 57b, and is located right above the power unit 36. There is. A control box 58 for controlling power supply to the electric motor 46 is mounted on the cross frame 57.

A DCDC converter 59 is mounted on the left side of the control box 58. This converter 59 has the following functions. That is, in this embodiment, the headlight, the turn signal, and the brake lamp are turned on by the auxiliary battery 12c arranged at the rear right corner of the chassis 2, but when the voltage of the auxiliary battery 12c drops, the DCDC The converter 59 charges the auxiliary battery 12c with electric power from the main batteries 12a and 12b, and at the same time, turns on the headlamp and the like.

Next, the function and effect of this embodiment will be described. In the rear wheel suspension system 6 of the present embodiment, the power unit 36 is mounted, and one rubber damper 40 is provided at the tip of one support tube 37c located at the center of the subframe 37 supporting the rear wheels 5, 5 in the vehicle width direction. Since, for example, only the left rear wheel 5 passes through the convex portion of the road surface, the sub-frame 37 is rotated around the axis of the support tube 37c by the elasticity of the rubber damper 40 because it is connected to the cross frame 10c via the. Thus, it is possible to absorb the impact from the convex portion and suppress changes in the posture of the vehicle body.

Also in this case, on the left side of the sub-frame 37,
Since the suspension links 44, 44 that oppose the front-rear direction load are provided on the right side, it is possible to oppose the input from the convex portion of the road surface to the rear wheel 5 on one side, and the sub-frame 37 in the plan view.
It is possible to prevent the vehicle from turning around 0, and also from this point, it is possible to suppress changes in the vehicle body posture and improve running stability.

Further, the force for rotating the sub-frame 37 in plan view can be more reliably countered by providing the lateral rod 54. This lateral rod 54
The right end rubber damper 54 of the rod 54
a is arranged and fixed on the subframe 37.
7, the bracket is connected to the input case 47b, which is an upper part of the rear wheel shaft, via the bracket 53. Therefore, the bracket from the sub-frame 37 side and the bracket from the cross frame side can be downsized and simplified.

That is, when the lateral rods are arranged substantially horizontally and in the vehicle width direction between the vehicle body frame and the sub-frame, since the vehicle body frame and the sub-frame are separated from each other in the height direction, the lateral direction is increased in the vertical direction. Although there is a concern that the extending support bracket becomes large, in the present embodiment, since the input case 47b located above the sub-frame is used, the bracket 56 can be made short.

Further, when the left and right rear wheels 5, 5 pass through the convex portion of the road surface, the sub-frame 37 swings upward around the rubber damper 40 to prevent the vehicle body from being pushed up. In this case, the left and right suspension links 44, 4
Since the axis line of the front end rubber damper 44b, which is the connecting portion of the vehicle body No. 4 to the vehicle body, is aligned with the axis line of the rubber damper 40 at the center of the subframe 37, the subframe 37 can be swung upward smoothly, and the traveling can be improved. The stability can be improved.

Further, the rubber damper 44a at the rear end of the suspension link 44 and the rubber damper 44b at the front end are arranged at a higher position and a lower position from the axle 60, respectively, and the suspension link 44 is arranged in a stationary state at the front lower position. When steering to the left and turning to the left, the right side of the vehicle body sinks due to centrifugal force, and the left side rises, so that the rubber damper 44b at the front end of the left suspension link 44 rises to horizontally move the left suspension link 44. The rear wheel 5 on the left side is pushed rearward so that the rear wheels 5 and 5 slightly change in the same phase as the steering direction, resulting in understeer, and steering stability is improved.

In disposing the power unit 36 on the sub-frame 37, the end surface on the pulley side of the electric motor 46 is fixed to the bracket 51 fixed on the sub-frame 37, that is, the drive on which a large torque acts. Since the bracket is used to support the portion close to the pulley 48, the supporting force of the bending moment acting on the electric motor 36 by the torque is increased, and the motor can be prevented from falling.

Furthermore, since the bracket 51 is extended and the extension 51b is fixed to the differential device 47 which is firmly connected and fixed to the sub-frame 37, the differential device 4
Since 7 itself functions as a reinforcing member, the supporting force for the bending moment can be further increased.

When the rear cushion 39 constituting the rear wheel suspension device 6 is connected to the vehicle body side, the portions of the left and right upper side frames 8b in the vicinity of the cushion bracket 8c are connected and fixed by a saucer-shaped cross frame 57. The rigidity of the vehicle body side support portion of the rear cushion 39 can be improved, and a space for disposing the control box 58 required for controlling the power unit 36 can be secured.

In order to secure the space for disposing the control box 58, since the cross frame 57 installed above the power unit 36 is used, the control box 58 is located near the electric motor 46, and the electric motor Noise generated by supplying a large current to 46 can be suppressed, and the control accuracy is improved accordingly.

In the above electric vehicle, the weight of the battery is large, and the weight balance may be deteriorated depending on the arrangement structure. In the present embodiment, the four batteries 12a are arranged below the seat 17 located on the rear wheel 5 side, and the two batteries 12b are arranged in front of the front wheel 3, so that, for example, all the batteries are rear wheels. It is possible to avoid the problem that the front wheel load, which tends to occur when the vehicle is arranged on the side, is too small.

The battery 12b is located in front of the front wheel 3.
Since the vehicle-body-side connecting portion of the strut bar 19 was used for the arrangement, the frame structure is rational without the need to improve the frame rigidity only for the battery arrangement. That is, in this embodiment, the center frame 9,
9 is extended forward, the extension portions 9a, 9a are connected and fixed by a cross plate 10g, the strut bar 19 is extended forward from the suspension arm 22, and the rubber damper 21 at the front end is connected to the cross frame 10g. Therefore, the front extension portion has high rigidity as it is. Therefore, for mounting the battery 12b, it suffices only to add the saucer-shaped battery case 18, and the frame structure is not particularly complicated by mounting the battery 12b on the front side of the front wheel.

When the strut type front cushion 25 constituting the front wheel suspension device 4 is fixed to the vehicle body side, the strut towers 26 are connected and fixed by the tower bar 27 extending horizontally in the vehicle width direction. The rigidity against falling in the width direction can be improved.

In this case, the space above the tower bar 27 is used as a space for disposing the accelerator converter 34 for converting the accelerator opening into an electric signal, and the space below the tower bar 27 is used for the charger 35. Since it is used as an arrangement space, an accelerator that is an important on-vehicle component for an electric vehicle and requires a relatively large space while securing a space for arranging a brake master cylinder 28, a steering gear box 31, etc., which are general on-vehicle components. The arrangement space for the converter 34 and the charger 35 can be secured.

Furthermore, in arranging the above-mentioned vehicle-mounted parts, since the vehicle-mounted parts are arranged rearward of the front edge of the tower bar 27, the tower bar 27 protects the vehicle-mounted parts in the event of a collision from the front. It also functions as a member.

[0051]

As described above, according to the present invention, the driving wheel side end surface of the electric motor is fixed to the support bracket, and the extension portion of the support bracket is fixed to the differential device fixed to the subframe. Therefore, since the differential motor itself functions as a reinforcing member via the support bracket while fixing and supporting the portion of the electric motor near the large torque acting, the supporting rigidity of the bending moment acting on the electric motor is increased, and the cost is reduced. There is an effect that the motor can be surely prevented from falling down without causing an increase.

[Brief description of drawings]

FIG. 1 is a left side view of an electric vehicle according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view of the automobile of the embodiment.

FIG. 3 is a left side view of a front portion of the automobile of the embodiment.

FIG. 4 is a plan view of a front portion of the example vehicle.

FIG. 5 is a front view of a front portion of the automobile of the embodiment.

FIG. 6 is a left side view of a partial cross section of the rear portion of the automobile of the embodiment.

FIG. 7 is a plan view of a rear portion of the automobile of the embodiment.

[Explanation of symbols]

 1 Electric Vehicle 36 Power Unit 37 Subframe 46 Electric Motor 46a Output Shaft 47 Differential Gear 47a Input Shaft 47c Differential Gear Case 48 Drive Pulley (Drive Wheel) 49 Driven Pulley (Driven Wheel) 50 V Belt (Transmission Belt) 51 Support bracket 51a extension

Claims (1)

[Claims] 1. An electric motor and a differential device are mounted on a sub-frame, and a drive wheel mounted on an output shaft of the electric motor and a driven wheel mounted on an input shaft of the differential device are transmission members. In the power unit of the connected electric vehicle, the case of the differential device is fixed to the sub-frame, the support bracket is arranged between the electric motor and the drive wheel, and the support bracket is fixed to the sub-frame. The drive wheel side end surface of the electric motor is fixed to the support bracket, the support bracket is extended to the differential gear side, and the extension portion is fixed to the driven wheel side end surface of the differential gear case. Power unit for electric vehicles.