Patent ID: 7827947

Claim:
A variable displacement pump for supplying a fluid pressure to a valve timing control device that has a lock state at engine start-up in which variable control of an open-and-closure timing of an engine valve of an internal combustion engine is restrained, and a release state after engine start-up in which the variable control of an open-and-closure timing of an engine valve is allowed by a fluid pressure, the variable displacement pump comprising: a pump unit including a suction portion, a discharge portion and a plurality of working fluid chambers, the pump unit being driven by the engine so as to discharge a working fluid that is introduced from the suction portion into the working fluid chambers, from the discharge portion according to change in volume of the working fluid chambers; and a chamber volume varying mechanism comprising: a moveable member that is displaceable according to a discharge pressure of the working fluid discharged from the discharge portion, the chamber volume varying mechanism varying the volumes of the working fluid chambers that are opened to the discharge portion in accordance with displacement of the moveable member, a first biasing member that always biases the moveable member in such a direction as to increase the volumes of the working fluid chambers; and a second biasing member that is disposed with a set load and applies a biasing force to the moveable member in such a direction as to increase the volumes of the working fluid chambers when the moveable member is displaced against a biasing force of the first biasing member by a predetermined amount or more, wherein the biasing force of the first biasing member is set such that the valve timing control device is shifted to the release state according to the discharge fluid pressure before the moveable member is displaced against the biasing force of the first biasing member.