Variable displacement vane pump

Abstract

A variable displacement vane pump has a pump body, a driving shaft rotatably supported by the pump body, a rotor rotatably driven by the driving shaft, a plurality of vanes radially extendably installed in respective slots arranged in a circumferential direction in the rotor, a cam ring rockably provided inside 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. At an outer circumference side of the cam ring inside the pump body, a seal member is provided and defines 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. Then, a control valve controls only a pressure of the second hydraulic pressure chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view in an axial direction of a vane pump according to an embodiment 1 (a control pressure is introduced into a second hydraulic pressure chamber).

FIG. 2 is a sectional view in a radial direction of the vane pump according to the embodiment 1 (an eccentricity amount of a cam ring is maximum).

FIG. 3 is a sectional view in a radial direction of the vane pump according to the embodiment 1 (the eccentricity amount of the cam ring is minimum).

FIG. 4 is a sectional view in a radial direction of the vane pump according to an embodiment 2 (a control pressure is introduced into a third hydraulic pressure chamber).

FIG. 5 is a sectional view in a radial direction of the vane pump according to an embodiment 3 (a third hydraulic pressure chamber is defined by a third seal member).

FIG. 6 is a sectional view in a radial direction of the vane pump according to an embodiment 3-1.

Claims

1. A variable displacement vane pump comprising: a pump body;a driving shaft rotatably supported by the pump body;a rotor provided inside the pump body and rotatably driven by the driving shaft;a plurality of vanes radially extendably installed in respective slots that are arranged in a circumferential direction in the rotor;a cam ring rockably provided inside 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;a first and a 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 an area inside the pump chambers, where volumes of the plurality of pump chambers increase by way of rotary motion of the rotor;an outlet port provided at least one of the first and second members and opening to an area inside the pump chambers, where the volumes of the plurality of pump chambers decrease by way of the rotary motion of the rotor;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; anda control valve controlling only a pressure of the second hydraulic pressure chamber.

2. The variable displacement vane pump as claimed in claim 1, further comprising: a communication groove communicating the first hydraulic pressure chamber and the inlet port.

3. The variable displacement vane pump as claimed in claim 2, wherein: the communication groove is formed on a surface of one of the first and second members, which faces to the cam ring.

4. The variable displacement vane pump as claimed in claim 2, wherein: the cam ring is supported on a supporting surface inside the pump body, and whereinthe supporting surface has a slope that gradually separates from a rock fulcrum of the cam ring toward the second hydraulic pressure chamber with respect to a reference line connecting a rotation center of the driving shaft and a median point positioned at a midpoint between an endpoint portion of the inlet port and a starting-point portion of the outlet port.

5. The variable displacement vane pump as claimed in claim 2, further comprising: biasing means for biasing the cam ring toward the first hydraulic pressure chamber.

6. A variable displacement vane pump comprising: a pump body;a driving shaft rotatably supported by the pump body;a rotor provided inside the pump body and rotatably driven by the driving shaft;a plurality of vanes radially extendably installed in respective slots that are arranged in a circumferential direction in the rotor;a cam ring rockably provided inside 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;a first and a 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 an area inside the pump chambers, where volumes of the plurality of pump chambers increase by way of rotary motion of the rotor;an outlet port provided at least one of the first and second members and opening to an area inside the pump chambers, where the volumes of the plurality of pump chambers decrease by way of the rotary motion of the rotor; anda 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, andthe rocking motion of the cam ring being controlled by controlling only one pressure of the second hydraulic pressure chamber from the first and second hydraulic pressure chambers.

7. The variable displacement vane pump as claimed in claim 6, wherein: the cam ring is supported on a supporting surface inside the pump body, and whereinthe supporting surface has a slope that gradually separates from a rock fulcrum of the cam ring toward the second hydraulic pressure chamber with respect to a reference line connecting a rotation center of the driving shaft and a median point positioned at a midpoint between an endpoint portion of the inlet port and a starting-point portion of the outlet port.

8. The variable displacement vane pump as claimed in claim 6, wherein: the pump body has an annular adapter ring provided outside the outer circumference of the cam ring, anda control pressure that regulates the pressure of the second hydraulic pressure chamber is introduced into the second hydraulic pressure chamber via a through hole formed at the adapter ring.

9. A variable displacement vane pump comprising: a pump body;a driving shaft rotatably supported by the pump body;a rotor provided inside the pump body and rotatably driven by the driving shaft;a plurality of vanes radially extendably installed in respective slots that are arranged in a circumferential direction in the rotor;a cam ring rockably provided inside 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;a first and a 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 an area inside the pump chambers, where volumes of the plurality of pump chambers increase by way of rotary motion of the rotor;an outlet port provided at least one of the first and second members and opening to an area inside the pump chambers, where the volumes of the plurality of pump chambers decrease by way of the rotary motion of the rotor;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;an orifice provided on an oil passage that communicates to the outlet port; anda control valve into which a differential pressure between upstream and downstream of the orifice is introduced, andthe control valve not controlling the first hydraulic pressure chamber but controlling the second hydraulic pressure chamber.

10. The variable displacement vane pump as claimed in claim 9, wherein: the seal member is formed of a pair of seal members provided at the outer circumference of the cam ring and define the first and second hydraulic pressure chambers around the outer circumference of the cam ring, anda control pressure regulated by the control valve is introduced throughout a pressure-receiving-surface inside the second hydraulic pressure chamber defined by the pair of the seal members.

11. The variable displacement vane pump as claimed in claim 9, wherein: the cam ring is supported on a supporting surface inside the pump body, and whereinthe supporting surface has a slope that gradually separates from a rock fulcrum of the cam ring toward the second hydraulic pressure chamber with respect to a reference line connecting a rotation center of the driving shaft and a median point positioned at a midpoint between an endpoint portion of the inlet port and a starting-point portion of the outlet port.

12. The variable displacement vane pump as claimed in claim 9, wherein: the pump body has an annular adapter ring provided outside the outer circumference of the cam ring, andthe control pressure that regulates the pressure of the second hydraulic pressure chamber is introduced into the second hydraulic pressure chamber via a through hole formed at the adapter ring.

13. A variable displacement vane pump comprising: a pump body;a driving shaft rotatably supported by the pump body;a rotor provided inside the pump body and rotatably driven by the driving shaft;a plurality of vanes radially extendably installed in respective slots that are arranged in a circumferential direction in the rotor;a cam ring rockably provided inside 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;a first and a 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 an area inside the pump chambers, where volumes of the plurality of pump chambers increase by way of rotary motion of the rotor;an outlet port provided at least one of the first and second members and opening to an area inside the pump chambers, where the volumes of the plurality of pump chambers decrease by way of the rotary motion of the rotor;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;an orifice provided on an oil passage that communicates to the outlet port; anda control valve into which a differential pressure between upstream and downstream of the orifice is introduced, andthe control valve controlling only a pressure of hydraulic pressure chamber that is located at the side where the discharge amount decreases by the rock of the cam ring and into which a control pressure is introduced, from the plurality of the hydraulic pressure chambers formed in the space outside the outer circumference of the cam ring.

14. The variable displacement vane pump as claimed in claim 13, wherein: the seal member defines the first hydraulic pressure chamber formed at the side where the discharge amount increases by the rock of the cam ring and the second and also a third hydraulic pressure chambers formed at the side where the discharge amount decreases by the rock of the cam ring around the outer circumference of the cam ring, andthe control valve controls the third hydraulic pressure chamber.

15. The variable displacement vane pump as claimed in claim 14, wherein: the control valve is provided at an outer circumference side of the third hydraulic pressure chamber.

16. The variable displacement vane pump as claimed in claim 14, wherein: the third hydraulic pressure chamber is formed at an outer circumference side of the outlet port.

17. The variable displacement vane pump as claimed in claim 14, further comprising: a plug member liquid-tightly provided and movable in an axial direction thereof with respect to the cam ring, and whereinthe third hydraulic pressure chamber is formed inside the plug member.

18. The variable displacement vane pump as claimed in claim 14, wherein: the seal member is formed of a first, a second and a third seal members provided outside the outer circumference of the cam ring,the first and second seal members define the first hydraulic pressure chamber and the second and the third hydraulic pressure chambers around the outer circumference of the cam ring,the third seal member defines the second hydraulic pressure chamber and the third hydraulic pressure chamber around the outer circumference of the cam ring, andthe third seal member is forced toward the cam ring by a pressure introduced into the third hydraulic pressure chamber, and sealing performance is secured.

19. The variable displacement vane pump as claimed in claim 13, wherein: the cam ring is supported on a supporting surface inside the pump body, and whereinthe supporting surface has a slope that gradually separates, toward the side where the pump discharge amount decreases, with respect to a reference line connecting a rotation center of the driving shaft and a median point positioned at a midpoint between an endpoint portion of the inlet port and a starting-point portion of the outlet port.

20. The variable displacement vane pump as claimed in claim 13, further comprising: a communication groove communicating the inlet port and the hydraulic pressure chamber that is located at the side where the discharge amount increases, from the plurality of the hydraulic pressure chambers formed in the space outside the outer circumference of the cam ring.