Flow control valve

Abstract

A flow control valve includes a valve body (21), the valve body (21) having a valve seat part (211) provided therein, with a valve port (112) formed in the valve seat part (211); a spool (12), the spool (12) being axially movable to open or close the valve port (112), with a pressure-equalizing channel (121) provided in the spool (12), the pressure-equalizing channel connecting the valve port (112) and a back-pressure chamber (14), wherein the spool (12) has a substantially cylindrical lower end (222), and a conical hole (223) is formed in the spool (12), the conical hole (223) forming part of the pressure-equalizing channel (121), a bottom end of the conical hole (223) being located on a bottom plane (224) of the lower end (222), and the ratio of the diameter of the bottom end of the conical hole (223) to the diameter of the lower end (222) being greater than 0.88. In the present application, the conical hole (223) is provided on the spool (12) of the flow control valve, the conical hole (223) forming part of the pressure-equalizing channel (121), with the bottom end of the conical hole (223) being located on the bottom plane (224) of the lower end (222) of the spool (12). The conical hole (223) is dimensioned so that the pressure distributed at a lower part of the spool (12) becomes uniform, so as to balance fluid pressures in the back-pressure chamber (14) and the valve port (112).

Dependencies are inferred from the claim text.