Valve assembly for brake fluid pressure control

Abstract

A brake fluid pressure control valve assembly includes a body having a single cylinder bore communicating inlet and outlet ports connected to a brake master cylinder and wheel brake cylinder, respectively. The cylinder bore accommodates the components of two separate valves, namely first, second and third seat members and first and second valve elements brought into and out of contact with seat surfaces of these seat members, as well as a spring interposed between the two valve elements, a pressure reducing piston and a by-pass piston. First and second passageways arranged in parallel each interconnect the inlet and outlet ports through two serially arranged valve cavities in the cylinder bore and are opened and closed in a prescribed manner by the two valves in cooperation with the spring and pistons. The third seat member has seal rings fitted in first and second annular grooves formed in its outer periphery for providing a seal between the outer periphery of the third seat member and wall surfaces of axially extending bores in the first and second seat members. The outer diameter of the third seat member is smaller than the inner diameter of the first and second seat members so that the inner peripheral portions of the these seat members will not be contacted by the third seat member. The first and second seat members are joined to each other by a pin press fitted into opposing holes formed in opposing end faces of these seat members.