Sliding-pocket variable-displacement pump with compensation chambers

A sliding vane pump comprising:

• a housing defining a first cavity and a seal groove;
• a slider disposed in the first cavity and having an outer circumferential wall and an inner circumferential wall that defines a second cavity, the slider defining first and second grooves each extending from the inner wall to the outer wall, wherein the slider and the housing cooperate to define opposing first and second control chambers;
• a spring disposed in the first control chamber and configured to bias the slider to a full-displacement position, wherein the second control chamber is configured to receive pressurized fluid to act against the spring and urge the slider to a low-displacement position;
• a rotor configured to rotate within the second cavity and having a plurality of vanes configured to seal against the inner wall to define a plurality of pumping chambers;
• a seal disposed in the seal groove and extending between the housing and the outer wall;
• a first compensation chamber defined between the housing, the outer wall and the seal, wherein the first compensation chamber is in fluid communication with a first of the pumping chambers via the first groove;
• and
• a second compensation chamber defined between the housing, the outer wall, and the seal, wherein the first and second compensation chambers are on opposite sides of the seal and wherein the second compensation chamber is in fluid communication with a second of the pumping chambers via the second groove.

A sliding vane pump comprising:

• a housing defining a first cavity and a seal groove;
• a slider disposed in the first cavity and having an outer circumferential wall and an inner circumferential wall that defines a second cavity, the slider defining first and second grooves each extending from the inner wall to the outer wall;
• a rotor configured to rotate within the first cavity and having a plurality of vanes configured to seal against the inner wall to define a plurality of pumping chambers;
• a seal disposed in the seal groove and extending to the outer wall;
• a first compensation chamber defined between the housing, the outer wall, and the seal and in fluid communication with the first groove;
• and
• a second compensation chamber defined between the housing, the outer wall, and the seal and in fluid communication with the second groove.