JPH11240348A - Vehicular electrically driven device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use electrically driven motors in an efficient rotational speed area by composing a brake of an electric machine connected to a repulsion receiving member, variably controlling a load of the electic machine, threby reducing a shock at the starting assist time and varying speed ratio between the electrically driven motor and wheels. SOLUTION: A vehicular electrically driven device has bilaterally paired differential devices 8L, 8R, and a pair of electrically driven motors 91, 9R. An electric machine 14 is arranged for braking ring gears 8b of the differential devices 8L, 8R. In starting assist control, the electrically driven motors 9L, 9R are first started in the same directions in the state that a load of the electric machine 14 is zero. The load of the electric machine 14 is thus gradually increased, while braking force of the ring gears is gradually increased. Rotational speed thereof is decreased, while the rotational speed of a carrior 8d is increased by the equivalent rate. Driving force of the rear wheels is gradually increased. As a result, a deceleration ratio between the motors 9L, 9R and the rear wheels can be varied, and efficient rotational speed alone can be adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric driving device for driving wheels of a vehicle by an electric motor.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus has been disclosed in
According to JP 79348, a pair of left and right differentials having first, second and third rotating elements and a pair of left and right electric motors respectively connected to the first rotating elements of both differentials are provided. ,
The second rotating elements of the two differentials are connected to the left and right wheels, respectively, and the third rotating elements of the two differentials are connected to each other, and the third rotating element is used as a reaction force receiving member by the two differentials. It is known that a transmission mechanism is configured to transmit output torque of each electric motor to each wheel by operating both electric motors in a state where the third rotating element is braked by a brake means.

The brake means is constituted by a dog clutch for connecting the third rotating element to a casing and stopping the rotation. When the dog clutch is turned on, both electric motors rotate forward or backward to rotate left and right. By driving both wheels in the forward or reverse direction to assist in starting forward or backward, turning off the dog clutch after starting, and rotating both electric motors in opposite directions when turning the wheels, The wheel on the turning outer wheel is accelerated, and the wheel on the inner wheel is decelerated to perform turning assist.

[0004]

In the above-mentioned prior art, when the start assist for starting the electric motor by turning on the dog clutch is started, the driving force of the wheels suddenly rises and a shock is generated. Since the reduction ratio between the wheel and the wheel is uniquely determined, it is necessary to change the rotation speed of the electric motor according to the change of the wheel speed at the time of starting, and use the electric motor only in the efficient rotation speed range It is difficult to reduce the size of the electric motor because it is necessary to obtain the required driving force of the wheels even in a low-efficiency rotation speed range.

[0005] In view of the above, the present invention reduces the shock at the start of start assist and varies the speed ratio between the electric motor and the wheels to use the electric motor in an efficient rotation speed range. It is an object of the present invention to provide an electric drive device for a vehicle that can be used.

[0006]

Means for Solving the Problems In order to solve the above problems,
The present invention is an electric drive device for driving wheels of a vehicle with an electric motor, in which a transmission mechanism having a reaction force receiving member is interposed between the electric motor and the wheels, and the reaction force receiving member is braked by a braking means. In a device that transmits an output torque of an electric motor to wheels by operating the electric motor in a braked state, a brake unit is configured by a generator connected to a reaction force receiving member, and a control that varies a load of the generator. Means are provided.

According to the present invention, the braking force of the reaction force receiving member changes in accordance with the load of the generator, and the output torque of the electric motor is gradually increased by gradually increasing the load of the generator at the start of starting assist. At the start of the start assist, it is possible to prevent a shock due to a sudden rise of the wheel driving force.

Further, when the braking force against the reaction force receiving member is small and the reaction force receiving member is reversed by the driving reaction force, the reduction ratio between the electric motor and the wheels increases, and the braking force of the reaction force receiving member increases. As a result, the reduction ratio becomes smaller. Therefore, without changing the rotation speed of the electric motor, it is possible to cope with the change in the wheel speed by changing the reduction ratio by changing the load of the generator and changing the braking force of the reaction force receiving member. it can. As a result, it is possible to use the electric motor only in an efficient rotation speed range, and the size of the electric motor can be reduced. Further, the generator can also function as a regenerative brake when braking the vehicle.

[0009]

FIG. 1 shows a front wheel drive vehicle in which right and left front wheels 3L and 3R are driven by an engine 1 via a transmission 2. Each front wheel 3L and 3R has a constant velocity joint 4a at both ends. Connected to the transmission 2 via the drive shafts 4L and 4R.

Connecting shafts 6L and 6R having constant velocity joints 6a at both ends are connected to driven left and right rear wheels 5L and 5R, respectively, and an electric driving device 7 is interposed between the connecting shafts 6L and 6R. ing.

As shown in FIG. 2, the electric driving device 7 includes a pair of left and right differentials 8L and 8R and a pair of electric motors 9
L, 9R. Each differential 8L, 8R includes a sun gear 8a, a ring gear 8b, and both gears 8a, 8b.
8d that supports planetary gear 8c meshing with
And a planetary gear type differential device comprising: Each electric motor 9L, 9R is connected to a sun gear 8a, which is a first rotating element of each differential 8L, 8R, by a reduction gear train 10 respectively.
L, 10R, and each differential device 8L,
The carrier 8d, which is the second rotating element of the 8R, is connected to each connecting shaft 6L,
6R, the ring gear 8b, which is the third rotating element of the two differentials 8L, 8R, is connected to each other. The two gears 8L, 8R connect the ring gear 8b to the reaction force receiving member. The transmission mechanism is configured as follows. The specifications of the sun gears 8a, the ring gears 8b, the planetary gears 8c, and the carriers 8d of the differential gears 8L and 8R are the same.

Each of the electric motors 9L, 9R is connected to each of driver circuits 12L, 12R controlled by the controller 11.
Power is supplied from the battery 13 via the.

The electric driving device 7 further includes a double differential device 8.
A generator 14 connected to the ring gear 8b is provided as braking means for braking the L and 8R ring gears 8b. The generated power is supplied to the generator 14 by the electric motor 9L,
9R and the load circuit 15 which supplies to the battery 13 are connected,
The load circuit 15 is controlled by the controller 11 to
To make the load variable.

When the front wheels 3L and 3R slip when starting on a slippery road surface, the controller 11 controls the rear wheels 4L and 4R.
Start assist control for driving R and turning assist control for increasing the speed of the rear wheel on the turning outer wheel and decelerating the rear wheel on the inner wheel when the vehicle turns are performed.

In the start assist control, first, the generator 14
The left and right electric motors 9 in a state where the load of the
L and 9R are activated in the same direction. In this case, the rotation of the sun gear 8a of each of the differentials 8L and 8R causes the planetary gear 8 to rotate.
c rotates, and a driving reaction force acts on the ring gear 8b in a direction opposite to the rotation direction of the sun gear 8a. When the load of the generator 14 is zero, the braking force applied to the ring gear 8b by the generator 14 is also zero, and the ring gear 8a is driven in the opposite direction to the sun gear 8a by the driving reaction force as shown by the line a in FIG. The carrier 8d remains stationary, and the output torque of the electric motors 9L, 9R is not transmitted to the rear wheels 5L, 5R.

After starting the electric motors 9L and 9R, the generator 1
4, the braking force of the ring gear 8b also gradually increases, the rotation speed of the ring gear 8b decreases, the rotation speed of the carrier 8d increases accordingly, and the rear wheel 5L , 5R gradually rise. Finally, as shown by the line b in FIG. 3, the rotation of the ring gear 8b is restricted, and the rotation speed of the carrier 8d, ie, the rear wheels 5L, 5R is reduced by the rotation speed of the electric motors 9L, 9R.
0L, 10R gear ratio, sun gear 8a and ring gear 8b
And a value obtained by dividing by a predetermined reduction ratio determined by the gear ratio. Further, it is possible to further increase the rotation speed of the rear wheels 5L and 5R by causing the generator 14 to function as a motor and rotating the ring gear 8b in the same direction as the sun gear 8a as shown by the line c in FIG. . After all, the electric motors 9L, 9
The speed reduction ratio between R and the rear wheels 5L, 5R can be varied, and the reduction ratio is reduced in accordance with the increase in the rear wheel speed at the time of starting, so that the electric motors 9L, 9R can be rotated at an efficient rotational speed. Can be used only in the area. Therefore, the electric motors 9L and 9R can be reduced in size, and the power generated by the generator 14 can be supplied to the electric motors 9L and 9R and the battery 13 to reduce power loss.

After the start, when the rear wheel speed increases to a predetermined speed, the power supply to the electric motors 9L and 9R is stopped, the load on the generator 14 is reduced to zero, and the start assist is terminated.
In this state, the ring gear 8 is rotated with the rotation of the carrier 8d.
b idles in the same direction as the carrier 8d, and the left and right rear wheels 5L,
The sun gear 8a does not rotate unless a differential rotation of 5R occurs.

In the turning assist control, the electric motor on the turning outer wheel is rotated forward and the electric motor on the inner wheel is reversed while the load on the generator 14 is kept at zero. For example, during a right turn, the left electric motor 9L rotates forward and the right electric motor 9R reversely rotates. According to this, the sun gear 8 of the left differential 8L
a rotates forward and the carrier 8d rotates forward with respect to the ring gear 8b, and the sun gear 8a of the right differential 8R reversely rotates and the carrier 8d rotates reversely with respect to the ring gear 8b. In this case, a reverse reaction force acts on the ring gear 8b of the left differential 8L, and a forward reaction acts on the ring gear 8b of the right differential 8R. Since 8b and 8b are connected to each other, both reaction forces are canceled. Therefore, based on the rotation speed of the ring gear 8b, the carrier 8d of the left differential 8L, that is, the left rear wheel 5L is accelerated, and the carrier 8d of the right differential 8R is increased.
d, that is, the right rear wheel 5R is decelerated. As a result, a driving force is applied to the left rear wheel 5L as the outer wheel and a braking force is applied to the right rear wheel 5R as the inner wheel to generate a yaw moment in the right turning direction, thereby assisting the turning.

During braking of the vehicle, the load on the generator 14 is increased, and the generator 14 functions as a regenerative brake to assist braking.

In the above embodiment, the start assist and the turn assist can be performed by using the two electric motors 9L and 9R. However, in the case where only the start assist is performed, FIG. As described above, one electric motor 9, one planetary gear type differential device 8, and one bevel gear type differential device for supplying electric power from the battery 13 via the driver 12 controlled by the controller 11 And an electric motor 9 connected to a sun gear 8a of the planetary gear type differential 8 via a reduction gear train 10, and a carrier 8d carrying a planetary gear 8c is connected to a differential case 16a of the bevel gear type differential 16 And the left and right side gears 16b, 16b pivotally supported by the differential case 16a are connected to the constant velocity joint 6a of the left and right connection shafts 6L, 6R. According to this, a transmission mechanism using the ring gear 8 b of the planetary gear type differential 8 as a reaction force receiving member is constituted by the two differentials 8 and 16, and the electric motor 9 is operated with the ring gear 8 b braked. Then, the output torque of the electric motor 9 is transmitted to the left and right rear wheels 5L, 5R via the two differential devices 8, 16.

A generator 14 as braking means is connected to the ring gear 8b, and a controller 11 is connected to the generator 14.
, The electric motor 9 is started with the load of the generator 14 initially set to zero, and then the load of the generator 14 is gradually increased, and the rear wheel 5L , 5R drive power gradually rises,
While maintaining the rotation speed of the electric motor 9 in the efficient rotation speed range, the reduction ratio is reduced to increase the rear wheel speed.

Although the embodiment in which the present invention is applied to the rear wheel driven vehicle of the front wheel drive vehicle has been described above, the same applies to the front wheel drive wheel of the rear wheel drive vehicle. The present invention can be applied.

[0023]

As is apparent from the above description, according to the present invention, the shock at the start of the start assist can be reduced, and the reduction ratio between the electric motor and the wheels can be varied.
Since the electric motor can be used only in the efficient rotation speed range, the size of the electric motor can be reduced.
Furthermore, the generator can function as a regenerative brake during braking.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of use of the apparatus of the present invention.

FIG. 2 is a skeleton diagram showing a first embodiment of the device of the present invention.

FIG. 3 is a diagram showing a mutual relationship among a motor speed, a wheel speed, and a speed of a ring gear.

FIG. 4 is a skeleton diagram showing a second embodiment of the device of the present invention.

[Explanation of symbols]

5L, 5R Rear wheel (wheel) 7
Electric drive device 8L, 8R, 8 Differential device (transmission mechanism) 8b Ring gear (reaction force receiving member) 9L, 9R, 9 Electric motor 11 Controller (control means) 14
Generator 15 Load circuit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Katsuhiro Kitamura, 1-4-1 Chuo, Wako, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Yorunori Kumagai 1-4-1, Chuo, Wako, Saitama No. In Honda R & D Co., Ltd.

Claims (1)

[Claims] An electric drive device for driving wheels of a vehicle with an electric motor, wherein a transmission mechanism having a reaction force receiving member is interposed between the electric motor and the wheels, and the reaction force receiving member is provided with a brake means. By transmitting the output torque of the electric motor to the wheels by operating the electric motor in a state where the brake is applied, the braking means is constituted by a generator connected to the reaction force receiving member, and the load of the generator is varied. An electric drive device for a vehicle, comprising a control unit.