JPH06278588A - Braking force controller - Google Patents

Abstract

PURPOSE:To specify the neutral position for a plunger by providing an actuator comprising a driving device for moving the plunger and a detecting device for detecting a driving amount of the driving device and a controller for controlling a driving amount of the driving device through detection of a lock or slip of a wheel. CONSTITUTION:When a wheel speed sensor 22 detects a locked state of a wheel 21 during driving on a road with a low frictional factor, a controller 60 switches a cut valve 30 to the second position for interrupting braking fluid piping 14. At the same time, a plunger 42 is moved downward, the volume in a control pressure chamber 49 is increased and the pressure of the braking fluid inside is decreased so that rotation of the wheel 21 is recovered. When the wheel speed sensor 22 detects the recovery of rotation of the wheel 21, the controller 60 moves the plunger 32 upward again for re-braking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device for controlling a braking force of a vehicle to brake an automobile or the like. And the anti-skid control (the braking torque applied to the wheels when the vehicle is braked is applied to the road surface to prevent the vehicle from accelerating because the driving wheel slips on the road surface due to excessive friction). The braking force control device is capable of preventing the wheel from locking and slipping on the road surface because it is too large in relation to the friction coefficient.

[0002]

2. Description of the Related Art Conventionally, as a device for performing traction and anti-skid control, there is a technique disclosed in Japanese Patent Laid-Open No. 3-5270. This is to control the braking force by changing the volume in the control pressure chamber by using the outer first plunger and the inner second plunger to change the volume in the wheel cylinder to increase or decrease the brake fluid pressure. It is what The neutral position of the plunger at this time is specified when the head of the second plunger is located very close to the first plunger or when the head is in contact with the first plunger.

[0003]

However, in the above-mentioned conventional technique, since the volume of the control pressure chamber is changed by the two plungers, it is inevitable that two plungers must be manufactured and the cost is increased. It becomes a factor of. Although it is conceivable to change the volume of the control pressure chamber with one plunger due to such a situation, there is a problem that the neutral position cannot be specified in the above-mentioned conventional technique.

The present invention can specify the neutral position with one plunger.

A technical problem is to provide a braking force control device.

[0006]

The technical means taken in the present invention for solving the above-mentioned technical problem is to provide a master cylinder and a wheel cylinder for outputting a brake fluid pressure in accordance with an operating force of a brake operating member. A valve device that selectively switches between communication and cutoff, a control pressure chamber that is provided in the housing and communicates with a wheel cylinder, a plunger that changes the volume of the control pressure chamber by moving inside the housing, and a drive device that moves the plunger. And a control device for detecting the lock or slip of the wheel and controlling the drive amount of the drive device.

[0007]

The function of the present invention will be described. The neutral position of the plunger can be specified by specifying the output value of the detecting device at a certain position of the driving device as the neutral position by the detecting device that detects the driving force of the driving device, and even with one plunger. It becomes possible to specify the neutral position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram of the braking force control system of this embodiment. In the figure, 10 is a master cylinder equipped with a brake fluid tank 11, and 20 is a wheel cylinder attached to a wheel 21. Further, in order to operate the master cylinder 10, a booster device 13 that boosts the pedaling force exerted on the brake pedal 12 is attached.
Further, a wheel speed sensor 22 that detects the rotation state of the wheel 21 and outputs it to the control device 60 is provided.

Master cylinder 10 and wheel cylinder 2
A cut valve 30 is provided on the brake fluid pipe 14 connecting 0
And an actuator 40 are provided. Cut valve 3
0 indicates the master cylinder 10 by the control device 60.
Is a solenoid valve for selectively switching between a first position for communicating between the wheel cylinder 20 and the wheel cylinder 20 and a second position for disconnecting between the master cylinder 10 and the wheel cylinder 20. The actuator 40 includes a housing 41, a plunger 42, a worm 43, a first gear 44, a second gear 45, a motor 46, and a rotation angle sensor 47. The plunger 42 is slidably disposed in the bore 41a formed on the inner peripheral surface of the housing 41 via a seal member 48, and the control pressure chamber 49 is formed by the bore 41a in the housing and the upper surface 42a of the plunger 42. Is forming. A threaded opening 42b is provided in the lower part of the plunger 42 in the figure, and a worm 43 is inserted into the opening 42b via a ball screw 50. The worm 43 has a ball bearing 51 on the housing 41.
, And a first gear 44 is fixed to the end portion. The first gear 44 is a second gear fixed to the output shaft 46a of the motor 46 whose rotation is controlled by the control device 60.
It meshes with the gear 45. The rotation angle sensor 47 detects the rotation angle of the first gear 44 and outputs it to the control device 60.

The control device 60 recognizes the rotation state of the wheels through the wheel sensor 22 and drives the motor 46 to set the braking force control device to the traction control or the anti-skid control.

Next, the operation of this embodiment will be described.

In normal braking operation, the cut valve 30 is in the first position communicating with the brake fluid pipe 14,
When the brake pedal 12 is depressed, the master cylinder 10
The brake fluid moves from the wheel cylinders 20 to the wheel cylinders 20, and the braking force is applied to the wheels 21. When the brake pedal 12 is released, the brake fluid flows back from the wheel cylinder 20 to the master cylinder 10, and the braking force on the wheels 21 disappears.
At this time, the plunger 42 is in the neutral position.

The neutral position is a position where the first gear 44 has rotated a predetermined amount from the top dead center or the bottom dead center of the plunger 42.

For example, when an excessive driving force is applied to the wheels 21 on a low friction coefficient road surface (snow road, icy road, etc.), the wheel speed sensor indicates that the wheels 21 slip on the road surface and are in a slip state. When detected by 22, the control device 60 switches the cut valve 30 to the second position that shuts off the brake fluid pipe 14, and at the same time, drives the motor 46 to move the plunger 42 upward in the drawing to control the control pressure chamber 49.
Reduce the volume of. As a result, the volume of the wheel cylinder 20, the brake fluid pipe 14, and the control pressure chamber 49 is reduced, and the pressure of the brake fluid in the wheel cylinder 20 is increased, so that the braking force is exerted on the wheel 21 from the wheel cylinder 20.
1 is braked to prevent the wheels 21 from idling.

The wheel 21 is no longer idling, and the wheel 21
When the wheel speed sensor 22 detects that the vehicle has gripped the road surface, the control device 60 drives the motor 46 to move the plunger 42 downward in the drawing, and the wheel 2 again.
Restore the driving force of 1. During traction control, the plunger 42 is moved upward to move the control pressure chamber 49 as described above.
By reducing the volume of the wheel 21, the wheels 21 are prevented from idling, and the vehicle is started with stability.

On the other hand, when the wheel 21 is subjected to an excessive braking force while traveling on the road surface having the low friction coefficient and the wheel speed sensor 22 detects the locked state of the wheel 21, the control device 60 causes the cut valve 30 to brake the brake fluid. At the same time as switching to the second position for shutting off the pipe 14, the motor 46 is driven to move the plunger 42 downward in the drawing, and the control pressure chamber 4
Reduce the volume of 9. As a result, the volumes of the wheel cylinder 20, the brake fluid pipe 14, and the control pressure chamber 49 increase, the pressure of the brake fluid inside decreases, and the rotation of the wheel 21 is restored. When the wheel speed sensor 22 detects that the rotation of the wheels 21 has been restored, the control device 60 drives the motor 46 to move the plunger 42 upward again to perform re-braking. During anti-skid control,
As described above, by moving the plunger 42 up and down, the vehicle can be stabilized and stopped without locking the wheels 21. The vehicle does not need to be stopped during the anti-skid control described above, and when the driver returns the brake pedal 12, the plunger 4
2 is returned to the neutral position, and the cut valve 30 is switched to the first position communicating with the brake fluid pipe 14.

As described above, it becomes possible to specify the neutral position with one plunger.

[0019]

The effects of the present invention will be described. A valve device that selectively switches between communication and cutoff between the master cylinder that outputs brake fluid pressure and the wheel cylinder according to the operating force of the brake operating member, the control pressure chamber that is provided in the housing and that communicates with the wheel cylinder, and the housing An actuator including a plunger that changes the volume in the control pressure chamber by moving the drive chamber, a drive device that moves the plunger, and a detection device that detects the drive amount of the drive device.
A braking force control device comprising a control device for detecting a lock or slip of a wheel to control a drive amount of a drive device, wherein the drive device is provided by a detection device for detecting a drive force of the drive device. By specifying the output value of the detection device at the predetermined position as the neutral position, the neutral position of the plunger can be specified, and the neutral position can be specified even with one plunger.

Moreover, since only one plunger is sufficient, the cost is low.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a braking force control device according to the present invention.

[Explanation of symbols]

 10 ... Master cylinder 14 ... Brake fluid piping 20 ... Wheel cylinder 21 ... Wheel 22 ... Wheel speed sensor 30 ... Cut valve 40 ... Actuator 42 ... Plunger 43 ... -Worm 44 ... First gear 45 ... Second gear 46 ... Motor 47 ... Rotation angle sensor 49 ... Control pressure chamber 60 ... Control device

Claims (1)

[Claims] 1. A valve device for selectively switching communication / interruption between a master cylinder that outputs brake fluid pressure and a wheel cylinder in accordance with an operation force of a brake operation member, and a control that is provided in a housing and communicates with the wheel cylinder. An actuator comprising a pressure chamber, a plunger for moving the inside of the housing to change the volume of the control pressure chamber, a drive device for moving the plunger, and a detection device for detecting the drive amount of the drive device, a wheel A braking force control device comprising a control device for detecting the lock or slip of the drive device and controlling the drive amount of the drive device.