Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Reexamination Certificate
1998-06-30
2001-05-15
Graham, Matthew C. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
C303S087000, C303S113500
Reexamination Certificate
active
06231132
ABSTRACT:
The present application is based on and claims priority under 35 U.S.C. § 119 with respect to Japanese Patent Application No. 09-174185 filed on Jun. 30, 1997, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to a vehicle brake control device. More particularly, the present invention pertains to a brake pressure control device for a vehicle for use in an anti-lock control apparatus, a traction control apparatus and/or an automatic brake control apparatus.
BACKGROUND OF THE INVENTION
A conventional brake pressure control device for a vehicle is disclosed in Japanese Patent Laid Open No. 8(1996)-133059. The brake pressure control device disclosed in this publication includes a master cylinder, a pressure control valve, and a changeover valve disposed between the master cylinder and the pressure control valve. The changeover valve is designed to be switched to connect the master cylinder and the suction port of a fluid pump to supply brake fluid to each of the wheel brakes from the master cylinder when the brake pedal is not operated.
This conventional brake pressure control device is applied to a diagonal dual brake circuit mainly installed on a front engine front wheel drive vehicle having a pair of brake circuits, one of which is connected to the front right wheel brake and the rear left wheel brake and the other one of which is connected to the front left wheel brake and the rear right wheel brake.
When the above described device is applied to a front-rear dual brake circuit that is primarily installed on a front engine rear drive vehicle having a pair of circuits, one of which is connected to the front wheel brakes (front brake circuit) and the other one of which is connected to the rear wheel brakes (rear brake circuit), the brake pressure increase rate generated by the fluid pump differs between the front brake circuit and the rear brake circuit because brake fluid consumption differs between the front wheel brake and the rear wheel brake. Therefore, vehicle passengers may feel uncomfortable by the brake force difference between the front and rear of the vehicle.
If two fluid pumps each having a different capacity are applied to the front brake circuit and the rear brake circuit to address the foregoing drawback, the cost of the overall brake pressure control device is significantly increased.
In light of the foregoing, a need exists for a brake pressure control device that is not susceptible to the disadvantages and drawbacks associated with other known brake pressure control devices.
It would be desirable to provide a vehicle brake pressure control device that is able to equalize brake pressure differentials between the front brake circuit and the rear brake circuit.
SUMMARY OF THE INVENTION
Based on the forgoing, the present invention provides a vehicle brake pressure control device that includes a master cylinder, a front wheel brake connected to the master cylinder through a front brake conduit, a rear wheel brake connected to the master cylinder through a rear brake conduit, a front reservoir connected to the front wheel brake and a rear reservoir connected to the rear wheel brake. A front control valve selectively connects the front wheel brake to one of the master cylinder and the front reservoir, and a rear control valve selectively connects the rear wheel brake to one of the master cylinder and the rear reservoir. A front fluid pump discharges brake fluid to the master cylinder from the front reservoir, while a rear fluid pump discharges brake fluid to the master cylinder from the rear reservoir. A front changeover valve selectively connects and disconnects the master cylinder to and from a discharge port of the front fluid pump, and a rear changeover valve selectively connects and disconnects the master cylinder to and from a discharge port of the rear fluid pump. A front suction conduit connects the master cylinder and a suction port of the front fluid pump while a rear suction conduit connects the master cylinder and a suction port of the rear fluid pump. A pressure arrangement mechanism is connected to the front brake conduit between the front control valve and the front changeover valve, and is connected to the rear brake conduit between the rear control valve and the rear changeover valve.
According to another aspect of the present invention, a brake pressure control device for a vehicle includes a master cylinder, a front wheel brake connected to the master cylinder through a front brake conduit, a rear wheel brake connected to the master cylinder through a rear brake conduit, a front reservoir connected to the front wheel brake, rear reservoir connected to the rear wheel brake, a front control valve for selectively connecting and preventing connection of the front wheel brake to the master cylinder, and a rear control valve for selectively connecting and preventing connection of the rear wheel brake to the master cylinder. A front fluid pump discharges brake fluid to the master cylinder from the front reservoir and a rear fluid pump discharges brake fluid to the master cylinder from the rear reservoir. A front changeover valve is provided for selectively connecting and disconnecting the master cylinder to and from a discharge port of the front fluid pump, while a rear changeover valve is provided for selectively connecting and disconnecting the master cylinder to and from a discharge port of the rear fluid pump. A front suction conduit connects the master cylinder and a suction port of the front fluid pump, and a rear suction conduit connects the master cylinder and a suction port of the rear fluid pump. The brake pressure control device also includes a mechanism connected to the front brake conduit and the rear brake conduit for equalizing brake pressure differentials between the front wheel brake and the rear wheel brake.
REFERENCES:
patent: 5040854 (1991-08-01), Arikawa
patent: 5342120 (1994-08-01), Zimmer et al.
patent: 5417483 (1995-05-01), Sigl
patent: 5567022 (1996-10-01), Linkner, Jr.
patent: 5984430 (1999-11-01), Koga et al.
patent: 6007163 (1999-12-01), Sawada
patent: 8-133059 (1996-05-01), None
Aisin Seiki Kabushiki Kaisha
Burns Doane , Swecker, Mathis LLP
Graham Matthew C.
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