Anti-locking hydraulic brake system

An antilock brake system including a brake pedal, a master cylinder having a piston stroked by said brake pedal and defining a working chamber, a wheel brake, a brake conduit connecting said working chamber to said wheel brake, a fluid reservoir, a relief conduit connecting said wheel brake to said reservoir, an inlet valve means interposed in said brake conduit and outlet valve means interposed in said relief conduit, pump means having a housing in which are defined a pumping chamber, an inlet in communication with said reservoir and the relief conduit, and an outlet in communication with said brake conduit and master cylinder working chamber;

• a damping mans assembly, said damping means assembly comprising:
• a closure member defining an interior camping space, said closure member having an open ended generally tubular portion received in and sealed to said pump housing with said open ended portion inc communication with said pumping chamber;
• a generally cylindrical valve body received within said tubular portion having an inflow passage extending axially through said valve body to said interior damping space of said closure member;
• a pressure valve mounted in said inflow passage in said valve body in communication with said pumping chamber and opening to allow flow through said in flow passage upon development of a predetermined pressure in said pumping chamber;
• an outflow passage including an annular space defined between an outside surface said valve body and an inside surface of said tubular portion allowing outflow from said interior damping space of said closure member extending in an axial direction back towards said pressure valve;
• connection means connecting said outflow passage to said brake conduit and master cylinder working chamber;
• a throttle restriction formed in said outflow passage;
• a check valve in said outflow passage mounted in said valve body axially spaced away from said pressure valve, said check valve allowing outflow from said interior damping space to said outflow passage but preventing reverse flow.