Hydraulic brake apparatus for a vehicle

Abstract

The present invention is directed to a hydraulic brake apparatus, which includes wheel brake cylinders, and a master cylinder for advancing a master piston in response to operation of a brake pedal. A power chamber is formed behind the master piston. A reaction piston is disposed, with the front end thereof exposed in the power chamber, so as to transmit a reaction force produced by the pressure in the power chamber to the brake pedal. A power source is provided for pressurizing brake fluid stored in a reservoir to supply power pressure to the power chamber. A solenoid valve is provided for opening and closing a return passage which connects the power chamber to the reservoir, thereby to return the brake fluid thereto. A detection device is provided for detecting the amount of operation of the brake pedal. The solenoid valve is controlled in response to the amount of operation detected by the detection device to reduce the amount of the brake fluid in the power chamber. As a result, even if the brake pedal is operated during the automatic pressurization, with the power pressure supplied by the power source, the brake fluid in the power chamber is reduced by controlling the solenoid valve to be opened and closed, to obtain a sufficient stroke of the brake pedal, so that an adequate brake feeling can be obtained.

Dependencies are inferred from the claim text.