FLOW PRESSURE CONTROL VALVE FOR VANE PUMP

摘要

PROBLEM TO BE SOLVED: To provide a flow pressure control valve for a vane pump capable of reducing a differential pressureΔP (Ps-Po) between the valve opening pressure Po when operating a pilot relief valve and the set pressure Ps. SOLUTION: A vane pump having a discharge quantity to be changed in response to the engine speed and a flow pressure control valve FV for controlling the supply flow to an output port and the maximum pressure with a variable throttle provided on the way of a flow passage for connecting a pump port P communicated with a discharge side of the vane pump to the output port PS are provided. The pump port is opened in a tank port T at an open degree corresponding to the position of a spool 21. A passage area of a passage 1R close to a flow control spring chamber 1K is formed smaller than the passage area of other communication passage except for the passage 1R by throttling so as to reduce the oil quantity between the throttle and a pilot relief valve RV, and a differential pressure between the valve opening pressure of the pilot relief valve and the set pressure is thereby reduced.