Hydraulic brake apparatus for a vehicle

Abstract

The invention is directed to a hydraulic brake apparatus which includes a master cylinder having a cylinder body and a master piston slidably disposed therein for defining a pressure chamber ahead of the master cylinder and a power chamber behind the master piston. A control piston is slidably disposed in the cylinder body ahead of the master piston to define the pressure chamber behind the control piston, and adapted to be moved in response to movement of the master piston. An auxiliary pressure source is provided for pressurizing brake fluid to generate a power pressure. A valve assembly having a regulator chamber defined ahead of the control piston is communicated with the auxiliary pressure source to regulate the power pressure into a regulated pressure in response to movement of the control piston, and adapted to supply the regulated pressure into the power chamber to assist the operation of the manually operated member. The valve assembly includes a valve seat disposed ahead of the control piston, and a control valve disposed ahead of the valve seat. An adjusting device is disposed ahead of the control valve, and engaged with a front end of the control valve to urge the control valve to be seated on the valve seat when the regulated pressure exceeds a predetermined pressure. And, a space defined between the adjusting device and the front end of the control valve is communicated with the reservoir.