DIRECTIONAL CONTROL VALVE

摘要

A directional control valve wherein a spool hole having an input port, an actuator port and a tank port is provided in a valve block, wherein a spool is slidably fitted in the spool hole at a position where it can establish and out off a communication between the input port, actuator port and tank port, wherein the input and tank ports are opened to first and second jointing surfaces of the valve block, respectively, and wherein a plurality of said valve blocks are connected to each other by superposing the first and second jointing surfaces to thereby establish communications between the input ports and the tank ports of the respective valve blocks, respectively, said directional control valve being characterized in that an annular groove is formed in an outside position of each of the ports in the second jointing surface of the valve block, that a drain merging passageway communicating with the annular groove is formed so as to be open to the first and second jointing surfaces of the valve block to thereby reduce the pressure of oil flowing through the drain merging passageway to a low pressure substantially equal to the atmospheric pressure.