INTERNAL-COMBUSTION-ENGINE OIL PUMP AND OIL-PUMP-RELIEF-PRESSURE CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a relief-pressure control device capable of stabilizing the behavior of a ball valve element and highly accurately controlling a relief pressure even if the ball valve element is used as a valve element of a solenoid selector valve.SOLUTION: A relief valve 3 includes: a relief valve element 9 sliding in response to a pump discharge pressure to change an opening area of a relief port 13; and a back pressure passage 15 communicating with a back pressure chamber 10. A solenoid selector valve 4 includes: an opening hole 22 on a tip end; a ball valve element 22 opening/closing the one opening hole 22; and a solenoid section 17 actuating the ball valve element 23 to be opened/closed in response to the pump discharge pressure. A pilot valve 5 includes a pilot valve element 31 changing an opening area of a discharge port 34 depending on a slide position.