Variable displacement vane pump

A variable displacement vane pump comprising:

• a housing including a fluid inlet and a fluid outlet;
• a control member positioned within the housing to alter displacement of the pump;
• a rotor rotatably mounted in relation to the control member to pressurize fluid as the fluid moves from the fluid inlet to the fluid outlet;
• a feedback path in communication with the fluid outlet for supplying a pressurized fluid;
• a first supply path in communication with the feedback path and the fluid inlet for providing the pressurized fluid from the feedback path to the fluid inlet;
• a second supply path in communication with the feedback path and the control member for providing the pressurized fluid from the feedback path to the control member, the first supply path and the second supply path being separate such that the first supply path and the second supply path do not communicate with one another;
• and
• a restrictor element that receives the pressurized fluid from the feedback path and causes the pressure of the pressurized fluid to drop before it reaches the first supply path and the second supply path.

A variable displacement vane pump having a housing with a pump chamber having a fluid inlet and a fluid outlet, a pump control ring disposed within the housing for altering the displacement of the pump by rotating between a first position that corresponds to a maximum volumetric capacity of the pump and a second position that corresponds to a minimum volumetric capacity of the pump, a vane pump rotor rotatably mounted within the pump control ring, and the vane pump rotor having a plurality of slidably mounted vanes engaging an inside surface of the pump control ring, the vane pump rotor having an axis of rotation eccentric from a center of the pump control ring, the vane pump rotor rotating to pressurize fluid as the fluid moves from the fluid inlet to the fluid outlet, comprising:

• a biasing element for urging the control ring toward the first position;
• a control chamber formed between the housing and the pump control ring, wherein fluid pressure within the control chamber urges the control ring toward the second position;
• a feedback path in communication with the fluid outlet for supplying a pressurized fluid;
• a first supply path in communication with the feedback path and the fluid inlet for providing the pressurized fluid from the feedback path to the fluid inlet;
• a second supply path in communication with the feedback path and the control chamber for providing the pressurized fluid from the feedback path to the control chamber;
• a valve for controlling flow of the pressurized fluid via the second supply path, wherein the valve moves between a fully open position in which flow of the pressurized fluid along the first supply path is not restrained by the valve and a fully closed position in which flow of the pressurized fluid along the first supply path is prevented by the valve, and moving the valve from the open position to the closed position increases the fluid pressure within the control chamber;
• and
• a restrictor element that receives the pressurized fluid from the feedback path and causes the pressure of the pressurized fluid to drop before it reaches the first supply path and the second supply path, wherein the restrictor element is located downstream from the feedback path, the second supply path is located unidirectionally downstream from the restrictor element, the valve is located unidirectionally downstream from the second supply path, and the first supply path is located downstream from the valve.