JP3138799B2 - Connection device between left and right wheels of vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting device provided between left and right wheels of a vehicle, particularly, right and left driven wheels not driven by an engine.

[0002]

2. Description of the Related Art Conventionally, as this type of connecting device, Japanese Patent Laid-Open Publication No. Hei 5-131855 discloses a first type of transmission device in which the rotation of one of the right and left wheels is increased between the left and right wheels and transmitted to the other wheel.
And a second connection path for reducing the rotation of one of the wheels and transmitting it to the other wheel, and a clutch is interposed in each of the two connection paths, so that one of the wheels becomes an inner wheel when turning. The clutch for the first connection path is engaged, and the clutch for the second connection path is engaged during turning when one of the wheels becomes the outer wheel, so that the outer wheel is positively increased in speed as compared with the inner wheel. In addition, there has been known one that generates a braking force on the inner wheel side and a driving force on the outer wheel side to improve turning performance.

[0003]

By the way, when starting on a slippery road such as a snowy road, it has been considered that the driven wheels are driven by a drive source such as an electric motor to perform start assist. It is desired that a start assist function can be obtained in addition to the above-described turning control function of generating a differential rotation between them to improve turning performance. It is an object of the present invention to provide a compact and inexpensive coupling device that meets the above demand and that can generate a differential rotation between left and right wheels using a drive source for starting assistance.

[0004]

Means for Solving the Problems In order to solve the above problems,
The present invention relates to a coupling device provided between left and right wheels of a vehicle, wherein a pair of differential devices having first, second, and third rotating elements and a first rotating element of both differential devices are provided. A pair of drive sources respectively connected to each other, connecting the second rotating elements of both differentials to left and right wheels, respectively, and connecting the third rotating elements of both differentials to each other, Brake means capable of restraining rotation of the element are provided.

When the vehicle starts moving, the brake means is operated and both driving sources are rotated forward or backward. According to this, the third rotating element of the two differentials functions as a reaction force receiver, The driving forces of the two drive sources are transmitted to the second rotating element via the first rotating element of the two differentials, and the left and right wheels are both rotated forward or backward to perform forward or reverse start assist.

After the vehicle starts moving, the brake means is released and both drive sources are stopped. In this case, if both drive sources are braked, the first rotary element of both differential devices functions as a reaction force receiver. The left and right wheels are the second rotating element of the two differentials and the third wheel
It becomes a state of being directly connected via the rotating element, and the differential rotation of the left and right wheels is suppressed, so that the straight running stability is improved.

When turning, the drive source connected to the wheel-side differential device serving as the outer wheel is rotated forward, and the drive source connected to the wheel-side differential device as the inner wheel is turned reversely. According to this, the outer wheel is accelerated and the inner wheel is decelerated, so that the turning performance is improved.

As described above, according to the present invention, the starting assist control, the turning control, and the differential limiting control can be performed by the organic combination of the differential device and the driving source. A coupling device is obtained. In particular, since the differential rotation between the left and right wheels is taken out by a differential device, the number of rotations required for turning control and differential limiting control is reduced, and sufficient deceleration is performed even when the output torque of the drive source is small. As a result, torque required for turning control and differential limiting control can be obtained.
Therefore, the drive source can be made small and compact.

In order to prevent a difference in rotational speed between the front and rear wheels during turning, it is desirable to equalize the amount of acceleration of the outer wheel and the amount of deceleration of the inner wheel to keep the average speed of the inner and outer wheels constant. If the rotational elements of the two differentials have the same specifications, the rotational speed of the outer wheel and the deceleration of the inner wheel can be increased simply by rotating one drive source and the other drive source forward and backward at the same speed. There is an advantage that the amount can be made equal and the control of the driving source becomes easy.

Each of the differentials is constituted by a bevel gear type differential in which a pair of side gears composed of bevel gears and a pinion meshing with both side gears are pivotally supported in a differential case. It is also conceivable to use a differential case, one side gear, and the other side gear as the and third rotating elements, respectively. However, in this case, the third
When the differential case, which is the first rotating element, is rotated by the drive source while the rotation of the other side gear, which is the rotating element, is restricted, the one side gear, which is the second rotating element, is rotated at an increased speed, and the driving torque transmitted to the wheels at the time of starting is reduced. descend.
Even when the differential case is the third rotating element and the other side gear is the first rotating element, one of the side gears as the second rotating element rotates at the same speed as the first rotating element, and the driving torque required for the start assist is reduced. To achieve this, a drive source having a relatively large output torque must be used, or a reduction gear having a large reduction ratio must be added.

On the other hand, each differential is constituted by a planetary gear type transmission comprising a sun gear, a ring gear and a carrier supporting a planetary gear meshing with the two gears.
When a sun gear is used as the rotating element, a carrier is used as the second rotating element, and a ring gear is used as the third rotating element, the sun gear serving as the first rotating element is driven by the driving source while the rotation of the ring gear serving as the third rotating element is restricted by the braking means. When rotated, the carrier as the second rotating element is decelerated and rotated at a predetermined reduction ratio. Therefore, a small driving source having a small output torque can be used. However, a small reduction ratio is sufficient, which is advantageous.

By the way, when one wheel is locked during braking or the like, and an excessive differential rotation occurs between the left and right wheels,
The driving source is reversely driven at a speed corresponding to the differential rotation, and the durability of the driving source deteriorates. In this case, the clutch means for releasing the connection between the left and right wheels or the connection between at least one of the differential devices and the corresponding one of the driving sources when the differential rotation between the left and right wheels becomes a predetermined value or more. If provided, the reverse driving of the drive source due to the differential rotation is prevented, which is advantageous in improving the durability of the drive source.

[0013]

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.

Connection shafts 6L and 6R having constant velocity joints 6a at both ends are connected to left and right rear wheels 5L and 5R, which are driven wheels, respectively, and a connection device 7 is interposed between both connection shafts 6L and 6R. .

As shown in FIG. 2, the coupling device 7 includes a pair of left and right differential devices 8L and 8R and a pair of drive sources 9L and 9R. Each differential 8L, 8R is provided with a sun gear 8a.
And a planetary gear type differential device comprising a ring gear 8b, and a carrier 8d supporting a planetary gear 8c meshing with the two gears 8a, 8b. Each of the driving sources 9L and 9R is connected to the sun gear 8a of each of the differentials 8L and 8R at a reduced speed via a reduction gear train 10L and 10R, and the carrier 8d of each of the differentials 8L and 8R is connected to each of the sun gears 8a. The ring gears 8b of the two differentials 8L, 8R are connected to the intermediate shaft 11 by connecting to the constant velocity joints 6a of the shafts 6L, 6R.
Are connected via. The sun gears 8a, the ring gears 8b, the planetary gears 8c, and the carriers 8d of the two differentials 8L and 8R have the same specifications.

Each of the driving sources 9L and 9R is constituted by a small electric motor and incorporates a planetary gear type speed reducer. Then, it is controlled by the controller 12 through each of the driver circuits 13L and 13L. Although not shown, each of the driver circuits 13L and 13R includes a conventionally known forward / reverse switching circuit and a regenerative brake circuit. Incidentally, the drive sources 9L and 9R can be constituted by something other than the electric motor, for example, a hydraulic motor.

The coupling device 7 further includes two differential devices 8L and 8L.
Brake means 14 for restraining rotation of R ring gear 8b
It has. The brake means 14 includes a fixed dog member 14 a fixed to the intermediate shaft 11 and an axially movable movable dog member 1 which is prevented from rotating with respect to the casing of the coupling device 7.
4b, the movable dog member 14b is moved forward and backward by a solenoid 14c controlled by the controller 12, engaged and disengaged from the fixed dog member 14a, and restrains and releases the ring gear 8b. I have. Incidentally, the brake means 14 may be constituted by a hydraulic clutch or an electromagnetic clutch which is prevented from rotating around the casing.

The controller 12 includes left and right front wheels 3L,
Wheel speed sensors 15L and 15R for detecting the speed of 3R,
Wheel speed sensor 1 for detecting the speed of left and right rear wheels 5L, 5R
6L, 16R, a brake lamp switch 17, a side brake switch 18, and a backlight switch 19
And a signal from the steering angle sensor 20 are input.

As shown in FIG. 3, the controller 12 receives a signal from a main controller (not shown) for controlling the engine 1 and the transmission 2, and determines whether or not the vehicle is in a start operation (S1). At the time of starting, start assist control is performed (S2), and after starting, turning control and differential limiting control are performed (S3).

Details of the start assist control are as shown in FIG. 4. First, it is determined whether or not the system is abnormal (Q
1) If there is no abnormality, a speed difference ΔV between the front wheel speed Vf and the rear wheel speed Vr is calculated (Q2), and it is determined whether or not ΔV exceeds a set value ΔVS (Q3). ΔV> △ VS when the front wheels, which are the driving wheels, are slipping. In this case, the rear wheel speed Vr, that is, the vehicle speed is equal to the set value Vr.
Start assistance is required until S (for example, 15 km / h) or more, while start assistance is useless when the brake is applied. Therefore, {V> △
In the case of VS, next, the rear wheel speed Vr is lower than VrS, the brake lamp is turned off, and the side brake switch is turned off.
It is determined whether or not the three conditions are satisfied (Q4, Q
5, Q6). When the three conditions are satisfied, it is determined whether or not the backlight is off (Q7). When the backlight is off, that is, when the vehicle is moving forward, the brake unit 14 is turned off.
Is turned ON (the dog clutch is engaged) and both drive sources 9
L, 9R are rotated forward (Q8), and when the backlight is ON, that is, when the vehicle is moving backward, the brake means 14 is turned on and both drive sources 9L, 9R are rotated in reverse (Q9).

Here, when the brake means 14 is turned on,
The ring gear 8b of the two differentials 8L, 8R is restrained, and the ring gear 8b functions as a reaction force receiver.
When the sun gears 8a of the two differentials 8L and 8R are rotated forward or backward by the gears L and 9R, the carrier 8d is rotated forward or backward in a decelerated state, and the required driving torque is applied to the left and right rear wheels 5L and 5R. The start is transmitted and assist is performed.

When there is an abnormality in the system or when starting assistance is unnecessary, that is, when ΔV ≦ ΔVS, or when Vr
When ≧ VrS, when the brake lamp is ON, or when the side brake switch is ON, the braking means 1
4 is turned off, and both drive sources 9L and 9R are stopped (Q10).

After the start, the brake means 14 is kept in the OFF state, but both the driving sources 9L and 9R are rotated forward and backward during the turning control. More specifically, the turning control is performed by, for example, rotating the drive source 9L forward and rotating the drive source 9R reversely during a right turn. When the drive source 9L rotates forward, the differential device 8
When the L sun gear 8a rotates forward, the carrier 8d rotates forward with respect to the ring gear 8b. When the driving source 9R rotates in reverse, the carrier 8d rotates reversely with respect to the ring gear 8b due to the reverse rotation of the sun gear 8a of the differential 8R. Is done. In this case, a reaction force in the reverse direction acts on the ring gear 8b of the differential 8L, and a reaction force in the forward direction acts on the ring gear 8b of the differential 8R, but both ring gears 8b, 8b Since they are connected to each other, both reaction forces cancel each other. Therefore,
Based on the rotational speeds of both ring gears 8b, 8b, the carrier 8d of the differential 8L, that is, the left rear wheel 5L, is accelerated, and the carrier 8d of the differential 8R, that is, the right rear wheel 5R is decelerated. You. As a result, a differential rotation occurs between the left and right rear wheels 5L and 5R, 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, and yaw momentum in the right turning direction is generated. Right turn performance is improved.

The sun gear 8 of the two differentials 8L, 8R
Since the rotational elements such as a and the ring gear 8b have the same specifications, if the absolute values of the rotational speeds of the two drive sources 9L and 9R are made equal, the amount of speed increase of the left rear wheel 5L and the right rear wheel 5R
And the average speed of the left and right rear wheels 5L and 5R becomes equal to the vehicle speed, so that wheel slip due to differential rotation between the front and rear wheels can be prevented. And both drive sources 9L, 9R
In order to make the absolute values of the rotation speeds of the two drive sources 9L,
All that is necessary is to make the absolute values of the current values flowing to the 9R equal.
Control of the driving sources 9L and 9R is facilitated.

During a left turn, the drive source 9L is reversed to decelerate the left rear wheel 5L as the inner wheel, and the drive source 9R is rotated forward to increase the speed of the right rear wheel 5R as the outer wheel. At the time of turning control, a target turning radius of the vehicle is calculated from the vehicle speed and the steering angle, and both drive units are set so that the value of the differential rotation between the left and right rear wheels 5L and 5R becomes a value that matches the target turning radius. Sources 9L and 9R are controlled.

The differential limiting control is performed by braking both drive sources 9L and 9R by closing the regenerative brake circuit during straight running or high-speed turning. According to this, the two differentials 8
The left and right sun gears 8a function as reaction force receivers. The rotation of the left rear wheel 5L is transmitted to the ring gear 8b of the differential device 8L via the carrier 8d, and the rotation of the right rear wheel 5R is differentially transmitted. The carrier 8d is attached to the ring gear 8b of the device 8R.
Is transmitted via And both ring gears 8b, 8b
Are connected to each other, the differential rotation between the left and right rear wheels 5L, 5R is regulated by the braking force of both drive sources 9L, 9R. As a result, when yaw momentum is applied to the vehicle due to disturbance or the like, a moment is generated that resists the moment, and the straight running stability and the high-speed turning stability are improved.

If an excessive differential rotation occurs between the left and right rear wheels 5L and 5R due to locking of one wheel during braking or the like, the two drive sources 9L and 9R are operated in a manner opposite to the turning control.
Are reversely driven at excessive speeds in the forward rotation direction and the reverse rotation direction, respectively, which adversely affects the durability of the drive sources 9L and 9R. Therefore, in the apparatus shown in FIG. 5, the intermediate shaft 11 for connecting the ring gears 8b of the two differentials 8L and 8R is divided, and the clutch means 21 is provided at the divided portion to provide the two differentials 8L and 8R.
Are connected via the clutch means 21 and the left and right rear wheels 5
When the differential rotation between L and 5R becomes equal to or greater than a predetermined value, the clutch means 21 is turned off to release the connection between the two differentials 8L and 8R. According to this, the left and right rear wheels 5
The reverse drive of both drive sources 9L and 9R due to the differential rotation between L and 5R does not occur, and both drive sources 9L and 9R due to excessive differential rotation do not occur.
Excessive rotation of R is prevented, and the durability of both drive sources 9L and 9R is improved.

In this embodiment, the clutch means 21 is a fixed dog member 2 fixed to one half of the divided intermediate shaft 11.
And a movable dog member 21b provided on the other half of the intermediate shaft 11 so as to be rotatable in the axial direction while being prevented from rotating. The movable dog member 21b is controlled by the controller 12 to be a solenoid. At 21c, the clutch means 21 is disengaged from the fixed dog member 21a,
Turn off. As shown in FIG. 6, the controller 12 performs the start assist control, the turning control, and the differential limiting control in the same manner as described above (S2, S3), and the differential rotation between the left and right rear wheels 5L, 5R is equal to or more than a predetermined value. Is determined (S4),
When the differential rotation is less than the predetermined value, the clutch means 21 is turned on (S5), and when the differential rotation is equal to or more than the predetermined value, the clutch means 21 is turned off (S6).

Incidentally, as the clutch means 21, an electromagnetic clutch or a hydraulic clutch may be used. In FIG. 5, the clutch means 21 is interposed between the two differentials 8L and 8R. However, the clutch 21 is provided between one differential and one corresponding rear wheel, for example, the differential 8L. Connection shaft 6L for left rear wheel 5L
May be interposed between the constant velocity joint 6a and
It may be provided at a position where the connection between the left and right rear wheels 5L, 5R can be released.

Also, when the connection between at least one of the differentials and the corresponding one of the driving sources is released, the two driving sources 9L, 9R due to the differential rotation between the left and right rear wheels 5L, 5R.
Does not occur, and therefore, as shown in FIG.
One differential, for example, sun gear 8a of differential 8L
A clutch means 21 may be interposed between the driving source 9L. In this case, the clutch means 21 may be ON / OFF controlled by the controller 12 in the same manner as described above. However, during normal running, the sun gears 8a of the differential devices 8L, 8R are connected to the left and right rear wheels 5L, 5R. The clutch means 21 is always on because it does not rotate unless there is a differential rotation between
The clutch means 21 may be turned off when the sun gear 8a rotates at a predetermined speed or more due to excessive differential rotation between the left and right rear wheels 5L and 5R.

Although the embodiment in which the present invention is applied to the connecting device between the rear wheels of the front wheel drive vehicle has been described above, the present invention can be similarly applied to the connecting device between the front wheels of the rear wheel drive vehicle.

[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 flowchart showing a control program according to the first embodiment;

FIG. 4 is a flowchart showing a subroutine for start assist control;

FIG. 5 is a skeleton diagram showing a second embodiment of the device of the present invention.

FIG. 6 is a flowchart illustrating a control program according to a second embodiment.

FIG. 7 is a skeleton diagram showing a third embodiment of the device of the present invention.

[Explanation of symbols]

5L, 5R Rear wheel (left and right wheels) 7 Connecting device 8L, 8R Differential device 8a Sun gear 8b Ring gear 8c Planetary gear 8d Carrier 9L, 9R Drive source 12 Controller 14 Brake means 21 Clutch means

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Isamu Hashizume 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-6-293226 (JP, A) JP-A Heisei 6-297977 (JP, A) JP-A-5-169991 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 23/04 B60K 6/02 B60K 17/356 B60K 23 / 08

Claims (4)

(57) [Claims] 1. A coupling device provided between left and right wheels of a vehicle, comprising a pair of differentials having first, second and third rotary elements, and a first rotary element of both differentials. And a pair of driving sources respectively connected to the left and right wheels of the two differentials.
A connecting device between left and right wheels of a vehicle, comprising a brake means for connecting the rotating elements to each other and restraining rotation of the third rotating element. 2. The connecting device between left and right wheels of a vehicle according to claim 1, wherein the specifications of the rotating elements of the two differentials are the same. 3. Each of the differentials is constituted by a planetary gear type transmission comprising a sun gear, a ring gear and a carrier supporting a planetary gear meshing with the two gears, wherein a sun gear and a second rotation element are used as first rotation elements. The connecting device between left and right wheels of a vehicle according to claim 1 or 2, wherein a carrier is used as the first rotating element and a ring gear is used as the third rotating element. 4. A clutch for releasing the connection between the left and right wheels or the connection between at least one differential device and one of the corresponding driving sources when the differential rotation between the left and right wheels becomes equal to or greater than a predetermined value. 4. A method according to claim 1, further comprising the step of:
The connecting device between the left and right wheels of the vehicle according to any one of the preceding claims.