Patent ID: 6065279
Filing Date: 2000-05-23
Classification: B60T

Abstract:
A master cylinder comprising:a piston disposed in a cylindrical bore formed in a body for moving freely in forward and rearward directions;a pressure generating chamber and a supply chamber formed in the body, the pressure generating chamber being separated from the supply chamber by the piston, the pressure generating chamber communicating with an output port and the supply chamber communicating with a reservoir storing brake fluid;said piston discharging brake fluid of increased pressure in said pressure generating chamber to said output port upon operation of said piston, and said piston being returned to a non-operating position by a return spring arranged within said pressure generating chamber;said piston having an opening portion communicating said supply chamber with said pressure generating chamber, said piston having an axis;a rod positioned within said opening portion, said rod including an axially extending hole;said supply chamber and said pressure generating chamber being communicated by a flow passage formed between an inner periphery of the opening portion of said piston and an outer periphery of said rod when said piston is positioned in the non-operating position;said flow passage being closed by a seal member arranged on the outer periphery of said rod when said piston moves a predetermined distance; anda check valve positioned within said piston along the axis of the piston for communicating said supply chamber with said pressure generating chamber only when said piston is in the non-operating position and said pressure generating chamber is under negative pressure.