JPH0891189A - Brake fluid pressure control device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent a decrease in braking ability caused by sticking of the spool of the brake fluid pressure control valve. [Structure] The master cylinder 2 linked to the brake pedal 1 is an input port 6 of a brake fluid pressure control valve 4L (4R).
L (6R) and the new port 7L (7R) are connected via open / close switching valves 11 and 12, and the pump 16 is on the open / close switching valve side and the brake fluid reservoir 1 is on the open / close switching valve 11 side.
5 has a structure in which the stepped spool 8L (8R) sticks and the braking performance is deteriorated by the new port 6L.
(6R) to prevent, and open / close switching valve 11,
By opening 12 to open / close switching valves 13 and 14, yaw rate feedback control that does not depend on brake operation is also possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for appropriately controlling a brake fluid pressure for braking a vehicle wheel or the like.

[0002]

2. Description of the Related Art As a brake fluid pressure control device of this kind, the applicant of the present application has previously proposed the following one described in Japanese Patent Application No. 5-73317.

That is, the brake fluid pressure control valve is provided with the master cylinder pressure from the brake master cylinder that responds to the depression of the brake pedal to the input port, and the brake fluid pressure control valve outputs this master cylinder pressure to the output port. Output to the brake wheel cylinder as brake fluid pressure. When the brake fluid pressure control valve is actuated in the direction to close the input port by the solenoid electromagnetic force, the brake fluid pressure control valve reduces the brake fluid pressure according to the magnitude of the electromagnetic force.

According to such a brake fluid pressure control device, it is possible to execute so-called anti-skid control in which the brake fluid pressure of the wheel is reduced when the wheel is in the brake lock state to prevent the brake lock of the wheel. In addition, by adding a pressure source separately from the brake master cylinder and enabling the wheels to be individually and automatically braked by the pressure from this, the yaw rate motion of the vehicle can be targeted. So-called yaw rate feedback control can also be executed.

[0005]

However, in such a conventional brake fluid pressure control device, when the valve body such as the spool of the brake fluid pressure control valve is stuck at the position where the input port is covered, the master cylinder pressure is reduced. It is only possible to supply the oil through the gap between the valve body and the casing, and there is a concern that the braking ability may deteriorate even though the other brake systems are normal.

SUMMARY OF THE INVENTION The main object of the present invention is to propose a brake fluid pressure control device in which the braking performance is not deteriorated even when the stick described above occurs.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a first input port for inputting a brake operating force corresponding pressure according to a brake operating force or a discharge pressure from an external hydraulic source, and a wheel cylinder of each wheel. An output port that outputs the brake operating force corresponding pressure directly or a control pressure obtained by adjusting the discharge pressure of an external hydraulic source based on the sliding of a spool,
In a brake control device provided with a brake fluid pressure control valve having a spool that slides inside and adjusts the open / close positions of the first input port and the output port, the first input port is closed. During this period, a second input port for inputting the brake operating force corresponding pressure is provided.

[0008]

In the present invention, the brake operating force corresponding pressure at the time of brake operation is supplied from the first input port of the brake fluid pressure control valve or the second input port opened after the first input port is closed. , It is always supplied and the brake fluid pressure is secured. In other words, even if the brake fluid pressure control valve sticks with the first input port closed, the pressure corresponding to the brake operating force is supplied through the second input port, brake fluid pressure is generated, and the wheels fail to brake. Can be prevented.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a brake fluid pressure control device of the present invention,
In the embodiment, which is configured as a brake fluid pressure control device for the left and right rear wheels, 1 is a brake pedal, and 2 is a brake master cylinder. The master cylinder 2 responds to the depression of the brake pedal 1 and outputs the master cylinder pressure corresponding to the depression force of the brake pedal from the two ports 2F and 2R. The master cylinder pressure from the port 2F is used for braking the left and right front wheels, and the master cylinder pressure from the port 2R is used for braking the left and right rear wheels. However, for the sake of simplicity, the master cylinder pressure from the port 2R is used here. Only the left and right rear wheel braking systems that use cylinder pressure will be described.

The brake system for the left and right rear wheels includes wheel cylinders 3L, 3R for braking the left and right rear wheels, and the following brakes are provided between the wheel cylinders 3L, 3R and the port 2R of the master cylinder 2, respectively. Use a hydraulic circuit. That is, the left and right rear wheel brake hydraulic pressure control valves 4L and 4R are provided in these hydraulic circuits, and these valves are connected to the output ports 5L and 5R to be connected to the wheel cylinders 3L and 3R and the port 2R of the master cylinder 2. Input ports (first input ports) 6L and 6R to be installed, and new ports (second input port)
Input ports) 7L, 7R and stepped spools 8L, 8
R, a spring 9L for biasing these spools to the left in the drawing,
9R and solenoids 10L and 10R have a common configuration.

Left and right rear wheel brake fluid pressure control valves 4L, 4R
The output ports 5L and 5R are arranged so as to be in the groove between the large-diameter land and the small-diameter land of the spool in the entire stroke range of the spools 8L and 8R, and the input ports 6L and 6R are Spool 8 with springs 9L and 9R
It is arranged so that it is fully open at the L and 8R bullet support positions.

Here, the springs 9L and 9R urge the stepped spools 8L and 8R to the left so as not to close the input ports 6L and 6R, and apply a force in the pressure increasing direction to the spools. is there.

Further, the port 2R of the master cylinder 2 is divided into two passages, one of which is connected to a new port 7L of the brake hydraulic pressure control valve 4L and a new port 7R of the brake hydraulic pressure control valve 4R via the open / close switching valve 11, and the other. Is the input port 6L of the brake fluid pressure control valve 4L via the open / close switching valve 12.
And the input port 6R of the brake fluid pressure control valve 4R.

Further, a brake fluid reservoir 15 is connected to the open / close switching valve 11 side via the open / close switching valve 13, and a pump 16 is connected to the open / close switching valve 12 side via the open / close switching valve 14.

In this circuit, the solenoids 10L, 1
The 0R and the open / close switching valves 11, 12, 13, and 14 can be controlled by the controller 100 that arithmetically processes information from various sensors.

Next, the operation will be described. First, during normal braking, the controller 100 opens and closes the switching valves 11, 1
2 is open and 13 and 14 are closed.

When the master cylinder pressure is generated by depressing the brake pedal 1 in this state, the master cylinder pressure is
Brake fluid pressure control valves 4L and 4R from the open / close switching valve 11
Is transmitted to the new ports 7L and 7R of the brake fluid pressure control valve 4L and 4R from the open / close switching valve 12 and to the input ports 6L and 6R of the brake fluid pressure control valves 4L and 4R. However, new ports 7L, 7R
Is a stepped spool 8L, 8R is an input port 6L, 6R
Is to be opened after closing.

Therefore, the spool 8L (8R) sticks, and the input port 6L (6R) or the new port 7L (7
R) even if either of them is blocked, the master cylinder pressure is supplied from one of the two ports of the brake fluid pressure control valve 4L (4R) through the output port 5L (5R) to the wheel cylinder 3L (3R). It is possible to prevent the wheels from being poorly braked by being transmitted to the vehicle.

Since the new port 7L (7R) of the brake fluid pressure control valve 4L (4R) is opened after the input port 6L (6R) is closed, the conventional brake fluid pressure control device shown below is used. Can also play a role.

For example, at the time of braking, the center of gravity moves to the front wheel portion according to the deceleration, so that the load on the rear wheel is reduced, the frictional force between the wheel and the road surface is reduced, and the rear wheel is likely to be locked. It is well known.

Therefore, the on-off switching valves 11 and 12 are closed,
13 and 14 are opened, information from various sensors is calculated by the controller 100, and the solenoid 10L (10
A signal is transmitted to R) and a solenoid current is supplied. This solenoid current causes the spool 8L (8R) to move to the right and closes the input port 6L (6R), and then the spool 8L (8R).
The brake fluid pressure is reduced due to the diameter (area) difference between the large diameter land and the small diameter land. By such an action, the wheel cylinder 3L (3R) is operated so that the wheel continues to rotate at a slip ratio (generally 10 to 20%) that maximizes the friction coefficient between the road surface and the wheel, that is, maximizes the frictional force between the road surface and the wheel. Anti-skid control for pressure reduction control can be performed.

Therefore, the braking lock of the rear wheels (wheels) is prevented, and the instability of the steering due to the increase of the braking distance of the vehicle and the change of the posture can be eliminated.

Further, the solenoid current of the brake fluid pressure control valve 4L (4R) is controlled so that the deviation between the target yaw rate obtained by calculating information from various sensors by the controller 100 and the actual yaw rate of the vehicle becomes zero. However, yaw rate feedback control can be performed to obtain a target yaw rate motion by applying a difference in braking force to the left and right wheels.

That is, when the controller 100 closes the open / close switching valves 11 and 12 and opens 13 and 14,
The pump 16 is connected to the input port 6L (6R), and the new port 7L (7R) is connected to the brake fluid reservoir 15. Therefore, the pump pressure from the pump 16 is applied to the brake fluid pressure control valve 4L (4L) regardless of the depression of the brake pedal 1.
In R), the solenoid 10L (10R) is energized with a solenoid current so that the deviation between the target yaw rate calculated by the controller 100 and the actual yaw rate of the vehicle becomes 0, and the spool 8L (8R) is moved to the right. Then, the new port 7L (7R) is opened to communicate with the brake fluid reservoir 15 to perform the yaw rate feedback control for controlling the pressure reduction of the wheel cylinder 3L (3R).

Thus, each wheel can be brake-controlled separately from the brake operation of the brake pedal 1, and can be used for yaw rate feedback control of the vehicle and behavior correction for lateral wind disturbance, for example.

[0026]

According to the present invention, the brake operating force-corresponding pressure at the time of brake operation is supplied to the wheel cylinder of the wheel through the input port and the output port of the brake fluid pressure control valve in order to brake the wheel. it can.

By the way, since a second input port which is opened after the port is closed and a circuit for supplying the pressure corresponding to the above-mentioned brake operating force is provided to this port, the hydraulic pressure control valve serves as the first input port. Even if the stick is made in the closed state, the pressure corresponding to the brake operating force is supplied through these circuits and the second input port instead of the first input port, and the brake fluid pressure may be generated, so that the wheel is braked. It can be prevented from becoming defective.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a brake fluid pressure control device of the present invention.

[Explanation of symbols]

 1 Brake pedal 2 Brake master cylinder 3L, 3R Wheel cylinder 4L, 4R Brake fluid pressure control valve 5L, 5R Output port 6L, 6R Input port (first input port) 7L, 7R New port (second input port) 8L , 8R Stepped spool 9L, 9R Spring 10L, 10R Solenoid 11, 12, 13, 14 Open / close switching valve 15 Brake fluid reservoir 16 Pump

Claims (1)

[Claims] 1. A first input for inputting a pressure corresponding to a brake operating force corresponding to a brake operating force or a discharge pressure from an external hydraulic source.
Input port and an output port that outputs the pressure corresponding to the brake operation force directly to the wheel cylinder of each wheel or a control pressure obtained by adjusting the discharge pressure of the external hydraulic source based on the sliding of the spool. And a spool that slides inside to adjust the opening / closing positions of the first input port and the output port, and a brake control device including a brake fluid pressure control valve, wherein the first input port is closed. The brake control device is provided with a second input port for inputting a pressure corresponding to the brake operating force during the operation.