STEUERVENTIL

摘要

A control valve is disclosed for use in controlling flow of hydraulic fluid from a hydraulic pump to a plurality of actuators. The control valve includes a valve housing within which are formed control bores, pressure-compensating bores, a feed passage communicating between the pressure-compensating bores, a selected-load pressure transmitting passage communicating between the pressure-compensating bores, a pair of return passages communicating between the control bores and a reservoir tank, control passages communicating respectively between each of the control bores and each of the pressure-compensating bores, and feeding and exhausting passages, as well as actuator ports, communicating between the control bores and the actuators. Control valve spools are slidably mounted, respectively, in the control bores, and pressure-compensating valves are slidably mounted, respectively, the pressure-compensating bores. One end of each of the pressure-compensating valves is subject to fluid pressure from the hydraulic pump and the other end is subject to fluid pressure due to loads of respective ones of the actuators. Shuttle valves are mounted in all but one of the pressure-compensating bores and are adapted to allow communication between either upstream and downstream portions of the selected-load pressure transmitting passage or between respective ones of the control passages and the downstream portion of the selected-load pressure transmitting passage. An unload valve is provided to connect the feed passage with the reservoir tank during periods of particular actuator loads.