Variable Displacement Pump

摘要

A variable displacement pump includes: a first urging member arranged to urge the cam ring in a direction to increase the eccentric amount; a second urging member arranged to urge the cam ring in a direction to decrease the eccentric amount; a control hydraulic chamber arranged to receive a discharge pressure, and thereby to move the cam ring against the urging force of the first urging member; and a hydraulic pressure introduction section configured to introduce the discharge pressure to the control hydraulic chamber when the discharge pressure becomes greater than a predetermined pressure which is in a range where the cam ring is movable against a resultant force of the urging forces of the first and second urging members, and where the cam ring is not movable only against the urging force of the first urging member.