Hydraulic brake apparatus for a vehicle

A hydraulic brake apparatus for a vehicle comprising:

• a hydraulic pressure generator which generates a power pressure irrespective of operation of a brake pedal and outputs the power pressure;
• a regulation valve which regulates the power pressure outputted from the hydraulic pressure generator to a predetermined pressure corresponding to an operation force of the brake pedal and outputs the predetermined pressure;
• a master cylinder having a first master cylinder pressure chamber and an auxiliary pressure chamber which is connectable to an output side of the regulation valve, the master cylinder being operated by an auxiliary pressure in the auxiliary pressure chamber to generate a master cylinder pressure corresponding to the auxiliary pressure in the auxiliary pressure chamber;
• a first wheel brake cylinder operated by the master cylinder pressure to apply braking force to a wheel of the vehicle;
• and
• pressure modulating means for modulating the auxiliary pressure to a pressure less than the predetermined pressure outputted from the regulation valve.

A hydraulic brake apparatus for a vehicle comprising:

• a pump for generating a power pressure irrespective of operation of a brake pedal;
• a regulation valve connected to the pump to regulate the power pressure outputted from the pump to a predetermined pressure corresponding to an operation force of the brake pedal;
• a master cylinder having an auxiliary pressure chamber which is connectable to an output side of the regulation valve and a first master cylinder pressure chamber, the master cylinder being operated by an auxiliary pressure in the auxiliary pressure chamber to generate a master cylinder pressure corresponding to the auxiliary pressure in the auxiliary pressure chamber;
• a first wheel brake cylinder receiving the master cylinder pressure to apply braking force to a wheel of the vehicle;
• a first valve located in a pressure passage connecting the regulation valve to the auxiliary pressure chamber;
• a second valve located in a pressure passage connecting the auxiliary pressure chamber to a reservoir;
• and
• a control device which controls the first and second valves to modulate the auxiliary pressure to a pressure less than the predetermined pressure outputted from the regulation valve.