Hydraulic brake pressure control valve assembly

Claim 1

A hydraulic pressure control valve assembly for a vehicle power brake system comprising in combination: a. a hollow cylindrical housing having a pressure chamber provided therein, said pressure chamber adapted for hydraulic communication with wheel bRake actuating means of a vehicle; b. a valve carrier slidably mounted in said cylinder and mechanically connected with a manually operated brake pedal; c. a piston slidably mounted within said pressure chamber adjacent said valve carrier, said piston having an axial bore therethrough, said piston further including a circumferential groove formed in its outer surface and a passage formed in said piston communicating said groove with said axial bore; d. an elongated valve member slidably positioned in said axial bore of said piston, said elongated valve member having an axial bore therethrough, said elongated valve member having an external surface portion cooperating with a valve seat formed on said piston around said axial bore therethrough on the end of said piston extending into said pressure chamber; e. a ball valve retained by the end of said valve carrier positioned adjacent said piston for cooperation with the end of said elongated valve member opposite said pressure chamber for selectively blocking said axial bore through said elongated valve member; f. biasing means disposed in said pressure chamber cooperation with said elongated valve member to bias said elongated valve member in the direction of said piston to move said elongated valve member into sealing engagement with the valve seat formed in said piston; g. first passage means communicating a hydraulic pump and regulator means with a port formed in said hollow cylindrical housing, said first port communicating with said groove formed in said piston slidably mounted within said pressure chamber, a pressure accumulating means connected in said first passage means between said first port and said pressure regulator, and a check valve means provided between said groove in said piston and said accumulator means, said pump means being operatively connected with a hydraulic reservoir, and a second passage means communicating said hydraulic reservoir with a second port formed in said hollow cylindrical housing between said valve carrier and the end of said piston opposite said pressure chamber, said ball valve adapted for blocking communication between said pressure chamber and said second port through the axial bore in said elongated valve member.