JPH0718481B2 - Vehicle drive torque distribution device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a drive torque distribution device that is used in a drive system of a vehicle and positively controls distribution of drive torque transmitted to left and right wheels.

(Prior Art) Conventionally, as a drive torque distribution device for actively controlling distribution of drive torque transmitted to the left and right wheels, Japanese Patent Laid-Open No. 62-944
The one shown in Japanese Patent No. 23 is known. In this conventional example, left and right hydraulic clutches are respectively provided between the final reduction gear and the left and right wheels, and the torque transmitted to the left and right wheels is positively controlled by individually controlling the hydraulic pressure supplied to the left and right hydraulic clutches. It is supposed to be controlled.

(Problems to be Solved by the Invention) However, the above-mentioned conventional example requires two independent hydraulic control systems because the left and right hydraulic clutches need to be controlled independently, and the structure becomes complicated. However, if the hydraulic clutch is damaged, there is a drawback that steering may become impossible.

(Structure of the Invention) The present invention was devised in view of the above points, and a differential device having an input member that receives a driving force from the engine side and left and right output members that are respectively connected to the left and right wheels. A reversible hydraulic motor provided between two of the three members and configured to relatively rotate the two members by a rotation output, and between a hydraulic power source and the hydraulic motor. A vehicle provided with a control valve that is provided to control the direction of the hydraulic pressure supplied to the hydraulic motor to control the rotational direction of the hydraulic motor, and a control unit that controls the operation of the control valve. Drive torque distribution device.

(Operation) According to the present invention, a reversible hydraulic motor is provided between the input member of the differential device and the two members of the left and right output members to relatively rotate the two members by rotational output. ,
Since the direction of rotation of this hydraulic motor is controlled by the control valve, it is possible to correct the torque distribution due to the action of the differential device by the rotation of the hydraulic motor. The distribution of the torque transmitted to the wheels of the vehicle can be actively controlled.

Further, since the action of the differential device is forcibly corrected by the hydraulic motor, traveling is not disabled even if the hydraulic motor fails.

Further, since the hydraulic motor is a reversible type, the number of used hydraulic motors is only one, and the control system is also one system, so that the structure is relatively simple.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, a differential device 1 includes a differential case 3 having a ring gear 2 and left and right side gears 7 and 8 meshed with a pinion gear 4 provided on the differential case 3 and connected to left and right output shafts 5 and 6, respectively. The ring gear 2 of the differential case 3 meshes with the drive pinion 10 provided on the shaft 9. The shaft 9 receives a driving force from the engine side (not shown). Therefore, the driving force transmitted from the shaft 9 to the ring gear 2 causes the differential case 3 to rotate, and the left and right side gears 7, 7 through the pinion gear 4, The drive torque is distributed to the eight (output shafts 5, 6), and the distributed drive torque is transmitted to the left and right wheels. Here, the ring gear 2 and the differential case 3 serve as input members, and the left and right output shafts 5,
The 6 and the side gears 7 and 8 form left and right output members.

A hydraulic motor is installed between the differential case 3 and the left output shaft 5.
The hydraulic motor 11 is provided with a reversible type in which the rotation direction can be reversed, and the rotational output of the hydraulic motor 11 causes the differential case 3 and the left output shaft 5 to relatively rotate.

As the hydraulic motor 11, a vane pump type is used. As shown in FIG. 2, the inner peripheral side of the rotor 12 has an output shaft 5
The inner peripheral side of the casing 13 is connected to the inner peripheral side of the differential case 3 while the rotor 12 is housed inside and the inner peripheral portion is formed in a cam ring shape. Hydraulic motor 11
Is a large number of holes on the outer peripheral surface 14 of the rotor 12 at equal intervals in the circumferential direction
15 are formed, and a vane 16 is fitted into each of these many holes 15 via a spring (not shown). Therefore, each vane 16 is in sliding contact with the cam ring-shaped inner peripheral portion of the casing 13 by the biasing force of the spring.

Three pressure chambers 17 are formed at equal intervals in the circumferential direction between the rotor 12 of the hydraulic motor 11 and the casing 13, and the casing 13 is provided at the circumferential end of each pressure chamber 19. Ports 18 and 19 are open. Each of these ports 18 is connected in parallel by an oil passage 20, and each port 19
Are connected in parallel by an oil passage 21. Therefore, in the hydraulic motor 11, when the high hydraulic pressure is introduced into the oil passage 20, the high pressure oil flows in from the port 18 and the rotor 12 becomes the casing.
It rotates clockwise with respect to 13 in FIG.
When a high hydraulic pressure is introduced into the cylinder, high pressure oil flows in through the port 19 and the rotor 12 rotates counterclockwise in FIG. The oil passages 20 and 21 are connected to the casing 29 of the differential gear 1 as shown in FIG. 1, and the annular oil passages 30 and 31 formed between the casing 29 and the differential case 3 and the differential case. The ports 18 and 19 are communicated with each other through the communication passages 32 and 33 formed in the port 3.

On the other hand, as shown in FIG. 1, the hydraulic pump 22 serving as a hydraulic pressure source is driven by the shaft 9 and sucks and discharges the oil in the reservoir 23. Since the shaft 9 rotates in proportion to the rotation of the output shaft of the transmission, the hydraulic pump 22 rotates in accordance with the vehicle speed and the amount of oil discharged is proportional to the vehicle speed. Supply oil passage 24 communicating with the discharge port of the hydraulic pump 22
An electromagnetic control valve 26 for controlling the hydraulic pressure acting on the hydraulic motor 11 is provided between the return oil passage 25 communicating with the reservoir 23 and the oil passages 20 and 21. Further, as shown in FIG. 2, the hydraulic pump 22 is provided in the bypass oil passage 27 connected to the supply oil passage 24 and the return oil passage 25.
A flow rate control valve 28 is provided that defines the upper limit of the flow rate of oil supplied from the control valve 26 to the control valve 26 side.

The control valve 26 is composed of a throttle control type spool valve, and the operating direction is switched by the current selectively supplied to the left and right solenoid coils 37, 36. The supplied oil passage (that is, the rotation direction of the hydraulic motor 11) is switched, and the magnitude of the hydraulic pressure output (that is, the rotational speed of the hydraulic motor 11) changes depending on the stroke amount that is determined by the magnitude of the supplied current. It has become a thing. When the solenoid coils 37 and 36 are not energized, the control valve 26
Is held in a neutral position by a neutral spring, and when the control valve 26 is in the neutral position, the oil passages 20 and 21 are in an equal pressure state, so that the hydraulic motor 11 does not rotate.

The operation of the control valve 26 is controlled by the drive current output from the controller 34 to the left and right solenoid coils 37 and 36. The controller 34 includes a steering angular velocity sensor 35 that detects the steering angular velocity of the steering wheel. The drive current to be output is controlled based on the detection output.

The control operation performed in the controller 34 will be described with reference to FIG. 3. First, at step S1, the steering angular velocity detected by the steering angular velocity sensor 35 is read, and then at step S2, from the -i map shown in FIG. The current value i to be output is read, and then the drive current output according to the current value i read in step S3 is supplied to the control valve 26. After step S3, the process returns to step S1 and the subsequent processing is repeated.

Here, as is apparent from FIG. 4, a dead zone is provided near the neutral position of the steering angular velocity, and the current value i output when the steering angular velocity exceeds the dead zone is the control valve 26.
Starting from a certain value or more in consideration of the starting force of, the output current value i increases in proportion to the increase of the steering angular velocity.

Next, the operation of this embodiment having the above-mentioned configuration will be described.

When the steering angular velocity detected by the steering angular velocity sensor 35 is in the dead zone shown in FIG. 4, such as when the steering wheel is in the steering holding state or when the steering wheel is steered slowly, the controller 34 drives the drive current. Is not output, the control valve 26 is held in the neutral position. Therefore, the ports 18 and 19 of the hydraulic motor 11 are in a constant pressure state and the hydraulic motor 11 does not rotate by hydraulic pressure. Therefore, in this state, the differential action is exerted only by the action of the differential device 1, and the torque is distributed in the same manner as in a general vehicle.

Further, when the steering wheel is steered relatively quickly and the steering angular velocity detected by the steering angular velocity sensor 35 is out of the dead zone shown in FIG. 4, a drive current value i corresponding to the steering angular velocity is supplied from the controller 34 to the control valve. Supplied to 26 solenoid coils. Now, considering the case where the steering wheel is steered to the right, a current i corresponding to the steering angular velocity is supplied to the solenoid coil 37 on the right side, and the control valve 26 is displaced leftward in FIG. The hydraulic pressure generated by the above acts on each pressure chamber 17 from each port 19 through the oil passage 21, and the high hydraulic pressure introduced from each port 19 causes the rotor 12 of the hydraulic motor 11 to move to the casing 13 relative to the casing 13. As shown by the arrow in Fig. 2, it rotates relative to the counterclockwise direction. Further, in FIG. 2, since the left side of the drawing is the front of the vehicle, the hydraulic motor 11
Rotation acts on the left drive shaft 5 via the rotor 12 in a direction to increase the driving force, and this reaction force acts on the differential case 3 via the casing 13.

Here, if the rotational torque of the hydraulic motor 11 is ΔT, the torque transmitted to the left drive shaft 5 increases by ΔT, and this reaction force −ΔT acts on the differential case 3, as shown in FIG. It will be. At this time, since the driving torque input from the engine side is sufficiently larger than the reaction force −ΔT transmitted to the differential case 3, the differential case 3 is not decelerated, and the reaction force −ΔT transmitted to the differential case 3 is , Through the pinion gear 4 to the left and right side gears 7, 8 respectively-
Each ΔT / 2 will be transmitted. Left side gear 7
Is connected to the drive shaft 5, so that in the drive shaft 5, the increase Δ in the drive torque directly transmitted from the hydraulic motor 11
The decrease of the drive torque transmitted from T by the side gear 7 −ΔT / 2 is subtracted, and the torque transmitted to the drive shaft 5 by the rotation of the hydraulic motor 11 increases by ΔT / 2. Also,
Since the right drive shaft 6 is connected to the right side gear 8, the decrease of the drive torque transmitted from the side gear 8 −ΔT / 2 is transmitted to the drive shaft 6 by the rotation of the hydraulic motor 11. Torque is reduced by ΔT / 2.

Therefore, when the steering wheel is steered to the right quickly, as shown in FIG. 6, the driving force of the right rear wheel on the turning outer wheel side increases by ΔF, while the driving force of the left rear wheel on the turning inner wheel side increases. The driving force will decrease by ΔF (ΔF
Will receive the braking force). Therefore, the additional yaw moment ΔM (Δ
(Fx tread) occurs, and the turning ability of the vehicle is improved.

Further, since the hydraulic motor 11 will rotate according to the steering angular velocity of the steering wheel, the rotation output of the hydraulic motor 11 will stop when the steering holding state is reached after the above yaw moment is generated at the beginning of turning. As a result, the stable turning of the vehicle is assured by the action of the differential device 1 alone.

Furthermore, when the steering wheel is quickly turned back from the steering state, the steering angular velocity is reversed, so that a yaw moment in the opposite direction to the above case is generated, and the return response from the turning state to the straight traveling state is improved.

Further, since the hydraulic pressure generated by the control valve 26 changes in accordance with the steering angular velocity and the vehicle speed, the rotation output of the hydraulic motor 11 also corresponds to the steering angular velocity and the vehicle speed, and the vehicle is properly operated in a wide range of vehicle traveling conditions. The turning ability will be improved.

According to the above embodiment, the differential motor 1 is provided with the hydraulic motor 11 and the rotation of the hydraulic motor 11 is controlled to forcibly correct the action of the differential gear to control the torque transmitted to the left and right wheels. Since it is possible, even if the hydraulic motor fails, the existence of the differential device 1 does not prevent the traveling, and the effect of excellent safety is achieved.

Further, since the hydraulic motor 11 is a reversible type, the number of units used is only one, and the control system is only one system, so the structure is relatively simple compared to the conventional one that controls the left and right clutches. Is an advantage.

Furthermore, the hydraulic motor 11 is rotated according to the steering angular velocity,
Since the drive torque transmitted to the wheel on the side opposite to the direction of the steering angular velocity is increased, the turning performance of the vehicle can be improved without a problem, and the turning feeling of the vehicle is improved. It should be noted that the present invention is not limited to the above-described embodiment, and the operation of the hydraulic motor may be controlled by another control logic, another type of hydraulic motor may be used, or the hydraulic motor may be left or right. Needless to say, various modifications may be made without departing from the scope of the present invention.

(Effects of the Invention) As described above in detail with the embodiments, according to the present invention, a reversible hydraulic motor and a differential device are used in combination to control the rotation of the hydraulic motor. It is possible to control the distribution of the driving torque transmitted to the left and right wheels with a relatively simple structure, and to provide an effect of providing a vehicle driving torque distribution device that is excellent in safety and can simplify the control system. Play.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram including an AA arrow view of FIG. 1, and FIG. 3 shows a control operation executed in the controller 34. 4 is a flowchart showing the relationship between the steering angular velocity and the output current value i, FIG. 5 is an explanatory view showing the action of torque distribution by the hydraulic motor, and FIG. 6 is an action on the behavior of the vehicle. It is operation | movement explanatory drawing demonstrated. 1 ... Differential, 3 ... Differential case, 5, 6 ... Output shaft, 11 ...
… Hydraulic motor, 22 …… Hydraulic pump, 26 …… Control valve, 34
...... Controller, 35 …… Steering angular velocity sensor

Claims (1)

[Claims] 1. A differential device having an input member for receiving a driving force from an engine side and left and right output members respectively connected to left and right wheels, and a differential device provided between two members of the three members. And a reversible hydraulic motor configured to relatively rotate the two members by a rotational output, and controls the direction of hydraulic pressure provided between the hydraulic power source and the hydraulic motor and supplied to the hydraulic motor. A drive torque distribution device for a vehicle, comprising: a control valve for controlling the rotation direction of the hydraulic motor, and control means for controlling the operation of the control valve.