To provide a flow control valve preventing cavitation in a pump chamber even when delivery pressure of an oil pump is high speed and low pressure.
A first pressure receiving surface 12 is provided on one end of a spool 11 of the flow control valve 1 and a second pressure receiving surface 13 having wide area than the first pressure receiving area 12 is provided on another end, hydraulic pressure (hydraulic pressure P1 before restriction, line pressure PL) before and after a restriction 5 is applied on the first pressure receiving surface 12 and the second pressure receiving surface 13 respectively. The flow control valve 1 changes orifice flow rate Qorf according to high and low of line pressure PL and orifice flow rate Qorf at a time of low line pressure PL gets small as compared to that at a time of high line pressure PL. Consequently, even if the oil pump 2 rotates at high speed, line pressure PL is low and cavitation tends to easily occur, large quantity of oil can be supplied into the pump chamber and cavitation can be surely prevented.
Tetsuro Maki
Maki Reiko