Radial piston pump

Claim 1

A radial piston pump, comprising a housing bounding a suction chamber therein and having an axis, said housing being provided with a plurality of pressure ports spaced from one another in a circumferential direction of said housing, and with at least one suction port; a plurality of valve units spaced from one another in the circumferential direction of said housing, each of said valve units including a pressure valve element located in a respective one of said pressure ports and performing the functions of controlling flow of a working fluid, and a separate threaded sleeve-shaped closure member mounted in the same pressure port radially outwardly of said pressure valve element and performing only the function of closing the same pressure port from outside and passing a pressure medium therethrough, so that a pressure chamber is formed radially between the pressure valve element and the separate closure member inwardly of and communicating with the pressure port; means communicating said pressure chambers with each other, including a plurality of channels which extend only circumferentially in said housing and intersect the respective pressure chambers formed between the respective pressure valve elements and the separate closure members; and a plurality of piston units spaced from one another in the circumferential direction of said housing and each having a piston and a cylindrical member connected therewith, each of said pressure valve elements sealingly abutting against a respective one of said cylindrical members of said piston units over an annular sealing surface which has a diameter smaller than a diameter of a respective one of said pressure ports in which said pressure valve element is located.