Patent ID: 8186969

Claim:
A variable displacement pump arranged to supply a lubricant to sliding portions of an internal combustion engine for a vehicle, and used as a source for actuating a variable valve actuating device arranged to control an actuation characteristic of valves of the internal combustion engine by a hydraulic pressure, the variable displacement pump comprising: a pump section arranged to be driven by the internal combustion engine, and to discharge the lubricant introduced from an induction portion to a plurality of hydraulic chambers, through a discharge portion, by volume variations of the hydraulic chambers; a variable mechanism arranged to move a movable member by using the discharge pressure of the lubricant, and to vary volumes of the hydraulic chambers which are opened to the discharge portion; and an urging section, which includes a first coil spring and a second coil spring and is arranged to urge the movable member in a direction to increase quantities of the volume variations of the hydraulic chambers, the urging section having a spring constant which increases as a movement distance of the movable member in a direction to decrease the quantities of the volume variations of the hydraulic chambers increases; wherein each of the first coil spring and the second coil spring of the urging section has a spring set load in a state in which the movable member is urged by the urging section so that the volume variations of the hydraulic chambers become maximized; wherein the first coil spring is located nearer to the movable member than the second coil spring, and the first coil spring constantly urges the movable member; wherein the second coil spring is configured to urge the movable member when a movement distance of the movable member is at least equal to a predetermined distance; and wherein the first coil spring and the second coil spring have different lengths in a disposed state, and the first coil spring is disposed radially inside the second coil spring.