Spool valve

摘要

A spool valve has a valve housing with a valve bore formed therein, a spool having a land portion slidably accommodated in the valve bore, a control port formed within the valve housing, able to communicate with the valve bore, and opened and closed by the land portion, and an annular groove open at an inner peripheral surface of the valve bore and communicating with the control port. Part of the control port is open over the inner and outer parts, as taken in the widthwise direction, of the annular groove. The degree of opening of the port is variably controlled by the displacement of the land portion.