Hydraulic control valve system

摘要

Disclosed is a hydraulic control valve system, for driving a plurality of hydraulic actuators by a single pump, including pressure compensation valves and a shuttle valve disposed in a vertical bore orthogonal to a lateral bore of a valve body, into which a spool of a direction switching valve is fitted. A load sensing chamber for introducing a load pressure of an actuator is formed at an intersection between the lateral bore and the vertical bore. An opening-side first pressure receiving surface of the pressure compensation valve confronts the load sensing chamber. The pressure compensation valve has an opening-side second pressure receiving surface contacting a pilot pressure in the vicinity of the opening-side first pressure receiving surface. Formed on the upper side of the pressure compensation valve are a closing-side first pressure receiving surface on which a bridge pressure acts and a closing-side first pressure receiving surface on which an external control pressure acts. The pressure compensation valve incorporates a throttle check valve working as a resistance at a descending time upon receiving a closing-side pressure in a region of the opening-side first pressure receiving surface.