Patent ID: 6363720
Filing Date: 2002-04-02
Classification: B60T

Abstract:
A master cylinder comprising:a cylinder body in which is formed a cylinder bore; a piston positioned in the cylinder bore for back and forth movement, the piston including a front portion and a rear portion which possess different diameters, the front portion defining a pressure chamber at its front side and an auxiliary pressure chamber at its rear side in such a manner that the auxiliary pressure chamber is located at the same position as the rear portion of the piston, the piston being moved upon brake operation, the front portion of the piston being movable relative to the rear portion of the piston; a first changeover valve establishing and interrupting fluid communication between the pressure chamber and the auxiliary pressure chamber independent of movement of the piston; and a second changeover valve establishing and interrupting fluid communication between the auxiliary pressure chamber and a reservoir supplying brake fluid to the auxiliary pressure chamber independent of movement of the piston.