Variable Capacity Vane Pump

A variable capacity vane pump comprising:

• a pump body;
• a driving shaft rotatably supported by the pump body;
• a rotor provided in the pump body and rotatably driven by the driving shaft;
• a plurality of vanes radially extendably installed in their respective slots that are arranged in a circumferential direction in the rotor;
• a cam ring rockably provided on a supporting surface in the pump body and forming a plurality of pump chambers at an inner circumference side of the cam ring in cooperation with the rotor and the vanes;
• first and second members provided at both sides in an axial direction of the cam ring;
• an inlet port provided at least one of the first and second members and opening to a section of the pump chamber where a volume of the pump chamber increases;
• an outlet port provided at least one of the first and second members and opening to a section of the pump chamber where the volume of the pump chamber decreases;
• and
• a seal member provided at an outer circumference side of the cam ring and defining a first hydraulic pressure chamber located at a side where a pump discharge amount increases and a second hydraulic pressure chamber located at a side where the pump discharge amount decreases in a space outside the outer circumference of the cam ring, and
• a space between adjacent vanes of the plurality of vanes being 1 pitch, and
• a center of the cam ring being offset to an inlet port side from a port reference line which connects a center of the driving shaft in a no-load state and a position that is a half-pitch-advanced position from an end edge of the inlet port or a position that is a half-pitch-advanced position from an end edge of the outlet port.

A variable capacity vane pump comprising:

• a pump body
• a driving shaft rotatably supported by the pump body;
• a rotor provided in the pump body and rotatably driven by the driving shaft;
• a plurality of vanes radially extendably installed in their respective slots that are arranged in a circumferential direction in the rotor;
• a cam ring rockably provided on a supporting surface in the pump body and forming a plurality of pump chambers at an inner circumference side of the cam ring in cooperation with the rotor and the vanes;
• first and second members provided at both sides in an axial direction of the cam ring;
• an inlet port provided at least one of the first and second members and opening to a section of the pump chamber where a volume of the pump chamber increases;
• an outlet port provided at least one of the first and second members and opening to a section of the pump chamber where the volume of the pump chamber decreases;
• and
• a seal member provided at an outer circumference side of the cam ring and defining a first hydraulic pressure chamber located at a side where a pump discharge amount increases and a second hydraulic pressure chamber located at a side where the pump discharge amount decreases in a space outside the outer circumference of the cam ring, and
• a space between adjacent vanes of the plurality of vanes being 1 pitch, and
• a center of the cam ring being offset to an inlet port side from a port reference line which connects a half-pitch-advanced position from an end edge of the inlet port in a rotation direction of the rotor and a half-pitch-advanced position from an end edge of the outlet port in a reverse direction to the rotation direction of the rotor.