CONTROL AND RELIEF VALVES

摘要

A spool is movable in the bore and has a pair of spaced annular grooves with spaced relief bore in the housing. A pump chamber and a work chamber in the housing intersect both bores. A pair of tank chambers, one on each opposite side of the pump and work chambers intersect the main bore. The tank chamber adjacent the work chamber intersects the relief bore. A tank bore connects the tank chambers and an inlet return bore intersects the tank chamber adjacent the work chamber. An inlet port is connected to the relief bore and jump chamber and connects to a pump outlet port. A tank port is connected to the tank bore and a pump inlet port and a return port are connected to the inlet return bore. The pump inlet port connects to a pump inlet port and the return port, to be connected to a source of return fluid. A combination check and relief valve assembly in the relief bore at the cylinder chamber act as a check between the inlet port and work chamber and relieve excess pressure from the work chamber to the adjacent tank chamber.