Fluid-pressure and analogous brake systems – Speed-controlled – And traction control
Reexamination Certificate
1999-07-20
2001-08-28
Oberleitner, Robert J. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
And traction control
C303S010000, C303S116100
Reexamination Certificate
active
06280006
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a brake hydraulic control device for use in a vehicle and, in particular, to a brake hydraulic control device for use in a vehicle which is able to control the brake hydraulic pressures of drive and driven wheel brakes respectively by drive wheel control valve means corresponding to the drive wheel brakes and driven wheel control valve means corresponding to the driven wheel brakes, and also which is capable of execution of anti-lock brake control (which is hereinafter referred to as ABS control) and traction control as well as behavior stabilization control in the vehicle take-a-turn operation.
2. Description of the Related Art
Conventionally, a brake pressure control device of the above-mentioned type is already known, for example, from Japanese Patent Unexamined Publication No. 9-221015 of Heisei and the like.
In the brake pressure control device for use in a vehicle that is disclosed in the above-cited Japanese Patent Unexamined Publication No. 9-221015 of Heisei, there are employed a main liquid passage cut-off valve and a bypass cut-off valve. In particular, the main liquid passage cut-off valve is interposed between the drive and driven wheel control valve means and a master cylinder, and the discharge ports of pumps are connected between the main liquid passage cut-off valve and the drive and driven wheel control valve means. The bypass cut-off valve is interposed between the master cylinder and a driven wheel brake, in particular, in a bypass passage which goes around the main liquid passage cut-off valve and driven wheel control valve means.
According to the above structure, while the main liquid passage cut-off valve is opened and the bypass cut-off valve is closed, the brake hydraulic pressures of the drive and driven wheel brakes are controlled by the drive and driven wheel control valve means, to thereby be able to execute the ABS control. And, while the main liquid passage cut-off valve and bypass cut-off valve are both closed, the pumps are operated and the brake hydraulic pressures of the drive wheel brakes are controlled by the drive wheel control valve means, so that the traction control under the non-brake operation condition can be executed. Further, while the main liquid passage cut-off valve and bypass cut-off valve are both closed, the pumps are operated and the brake hydraulic pressures of the drive and driven wheel brakes are controlled by the drive and driven wheel control valve means, so that the behavior stabilization control in the vehicle take-a-turn operation under the non-brake operation condition can be executed.
Also, when the brake operation is executed during execution of the traction control or during the behavior stabilization control in the vehicle take-a-turn operation, the brake pressures of the driven wheel are increased by opening the bypass cut-off valve, to thereby prevent the delayed act or effect of the brakes when such control is terminated, which allows the driver to carry out such braking operation that corresponds to the intention of the driver.
However, in the above-mentioned conventional brake pressure control device, in order to prevent the delayed action or effect of the brake at the time of termination of the control, there are necessary the main liquid passage cut-off valve, the bypass passage which goes around the main liquid passage cut-off valve and driven wheel control valve means and is provided between the master cylinder and a driven wheel brake, and the bypass cut-off valve disposed in the bypass passage. Therefore, the number of parts required in the brake pressure control device is increased and the configuration of a hydraulic circuit is complicated.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional brake pressure control device. Accordingly, it is an object of the invention to provide a brake pressure control device for use in a vehicle which, using a hydraulic circuit which requires a reduced number of parts and is simplified in configuration, not only is able to execute the ABS control, traction control, and behavior stabilization control in the vehicle take-a-turn operation, but also, during execution of the traction control and behavior stabilization control in the vehicle take-a-turn operation, is able to prevent the delayed action or effect of the brake, which could otherwise occur as the brake operation is carried out, at the time of termination of the control.
In attaining the above object, according to a first aspect of the invention, there is provided a brake hydraulic control device for use in a vehicle, including: a master cylinder with a first reservoir attached thereto; second reservoirs different from the first reservoir; drive wheel control valve means capable of switching communication and cut-off between drive wheel brakes and the master cylinder as well as communication and cut-off between the drive wheel brakes and second reservoirs; and, driven wheel control valve means capable of switching communication and cut-off between driven wheel brakes and master cylinder as well as communication and cut-off between the driven wheel brakes and second reservoirs, wherein the suction ports of pumps, the discharge ports of which are connected between the drive wheel brakes and drive wheel brakes, are connected to the master cylinder through open/close switch valves and to the second reservoirs.
According to the present structure, in a normal brake operation, with the open/close switch valves closed, communication between the master cylinder and drive and driven wheel brakes is allowed and, at the same time, communication between the drive and driven wheel brakes and second reservoirs is cut off by the drive and driven wheel control valves. Thus, the brake pressure from the master cylinder is applied onto the drive and driven wheel brakes, so that a brake force corresponding to the amount of the brake operation can be obtained.
Also, in the ABS control, the open/close switch valves remain closed. In particular, in the brake hydraulic pressure reduction operation thereof, using the drive or driven wheel control valve means, communication between the master cylinder and drive or driven wheel brakes is cut off and communication between the drive or driven wheel brakes and second reservoirs is allowed, thereby reducing the brake hydraulic pressures of the drive or driven wheel brakes. In the brake hydraulic pressure retention operation thereof, using the drive or driven wheel control valve means, communication not only between the master cylinder and drive or driven wheel brakes but also between the drive or driven wheel brakes and second reservoirs is cut off, thereby retaining the brake hydraulic pressures of the drive or driven wheel brakes. In the brake hydraulic pressure retention operation of the drive wheel brakes, using the drive wheel control valve means, communication not only between the master cylinder and drive wheel brakes but also between the drive wheel brakes and second reservoirs is cut off, and, by actuating the pumps, the brake hydraulic pressure given by the brake fluid drawn from the second reservoirs are applied onto the drive wheel brakes, thereby increasing the brake hydraulic pressures of the drive wheel brakes. Further, in the pressure increase operation of the driven wheel brakes, using the driven wheel control valve means, communication between the master cylinder and driven wheel brakes is allowed and communication between the driven wheel brakes and second reservoirs is cut off, and the brake hydraulic pressure from the master cylinder are applied onto the driven wheel brakes, thereby increasing the brake hydraulic pressures of the driven wheel brakes.
Thus, in the ABS control of the drive wheel brakes, since the pressure reduction, pressure retention and pressure increase of the drive wheel brakes are repeated in this manner, the brake fluid within the second reservoirs is drawn by the pumps to thereby eliminate th
Kobayashi Masashi
Yamazaki Ryouji
McGuireWoods LLP
Nissin Kogyo Co. Ltd.
Oberleitner Robert J.
Torres Melanie
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