Vane pump

Patent metadata

Field	Value
Publication number	US-9556867-B2
Application number	US-201414516938-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Oct 21, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A vane pump includes a rotor including a first annular groove and a second annular groove. The rotor further includes a cylindrical portion projecting axially from a radial inner side of the first annular groove and fitting over a drive shaft, and a slide contact portion formed on a radial inner side of the second annular groove. The cylindrical portion is slidably received in a bearing hole formed in a first side wall of a housing, whereas the slide contact portion abuts slidably on an inside wall surface of a second side wall of the housing. There is further formed, in the first annular groove, a recessed portion making a pressure receiving area of one of the first and second annular grooves greater than a pressure receiving area of the other of the first and second annular grooves.

First claim

The invention claimed is:

1. A vane pump comprising:
a housing including first and second side walls confronting each other and having therein an inside chamber to receive a pump element;
a drive shaft which extends in an axial direction and which is received rotatably in first and second through holes formed, respectively, in the first and second side walls of the housing;
a rotor mounted on the drive shaft and arranged to be driven rotationally by the drive shaft, and to serve as at least part of the pump element, the rotor including a first annular groove formed in a first axial end surface of the rotor, and a second annular groove formed in a second axial end surface of the rotor;
a plurality of vanes received, respectively, in a plurality of slits formed radially in an outer circumferential portion of the rotor and arranged to slide radially in the slits, respectively;
first and second guide rings received, respectively, in the first and second annular grooves and arranged to push the vanes radially outwards in the slits in accordance with rotation of the rotor;
the rotor including
a cylindrical portion which is formed integrally on a radial inner side of the first annular groove, and which projects in the axial direction from the first axial end surface, along the drive shaft, and
a slide contact portion formed on a radial inner side of the second annular groove in the second end surface;
an outside circumferential surface of the cylindrical portion of the rotor being slidably disposed in an inside circumferential surface of the first through hole of the first side wall of the housing, whereas the slide contact portion of the rotor includes a slide contact surface abutting slidably on an inside wall surface of the second side wall of the housing;
a pressure receiving area in the axial direction, of one of the first and second annular grooves being set greater than a pressure receiving area in the axial direction, of the other of the first and second annular grooves.

2. The vane pump as recited in claim 1 , wherein the vane pump further comprises a cam ring which is received in the inside chamber of the housing, which includes an inside circumferential surface put in sliding contact with forward ends of the vanes, and which is arranged to swing in accordance with a pump discharge pressure and thereby to vary a volume of a pump chamber defined by the rotor and the vanes.

3. The vane pump as recited in claim 2 , wherein the vane pump further comprises:
a first urging member to urge the cam ring in a direction to increase an eccentricity of the cam ring with respect to a rotation center of the rotor; and
a second urging member to urge the cam ring in a direction to decrease the eccentricity of the cam ring with an urging force smaller than an urging force of the first urging member in a state in which the eccentricity of the cam ring is greater than or equal to a predetermined level, and to store the urging force without applying the urging force to the cam ring in a state in which the eccentricity of the cam ring is smaller than the predetermined level.

4. The vane pump as recited in claim 2 , wherein the vane pump further comprises:
a pivot pin provided between an outside circumferential surface of the cam ring and an inside circumferential surface of the housing and arranged to serve as a fulcrum for a swing motion of the cam ring;
an urging member to urge the cam ring in a direction to increase an eccentricity of the cam ring with respect to a rotation center of the rotor;
a first control pressure chamber formed between the outside circumference surface of the cam ring and the inside circumferential surface of the housing, and arranged to swing the cam ring with an oil pressure introduced into the first control pressure chamber, against the urging force of the urging member;
a second control pressure chamber arranged to swing the cam ring with an oil pressure introduced into the second control pressure chamber, in a direction of the urging force of the urging member; and
a solenoid selector valve to control supply and discharge of a discharge pressure to the first control pressure chamber and the second control pressure chamber.

5. The vane pump as recited in claim 4 , wherein the solenoid selector valve is adapted to be controlled by a control unit in accordance with a parameter including at least one of an engine temperature, an engine load and an engine speed of an internal combustion engine.

6. The vane pump as recited in claim 1 , wherein the rotor includes a step portion formed between an inner circumferential surface of the first annular groove and an outside circumferential surface of the cylindrical portion, and arranged to increase the pressure receiving area of the first annular groove.

7. The vane pump as recited in claim 6 , wherein the step portion is formed by a first portion which is equal in diameter to the outside circumferential surface of the cylindrical portion and a second portion which forms the inner circumferential surface of the first annular groove and which is connected with the first portion in a form of a step.

8. The vane pump as recited in claim 7 , wherein the inner circumferential surface of the first annular groove is equal in diameter to an inner circumferential surface of the second annular groove.

9. The vane pump as recited in claim 8 , wherein the second portion of the step portion is arranged to regulate movement in a radial inward direction of the guide ring in the first annular groove.

10. The vane pump as recited in claim 9 , wherein the first portion of the step portion includes an outside circumferential surface substantially equal in outside diameter to the outside circumferential surface of the cylindrical portion.

11. The vane pump as recited in claim 1 , wherein an outside circumferential surface of the cylindrical portion is continuous with an inner circumferential surface of the first annular groove.

12. The vane pump as recited in claim 11 , wherein the outside circumferential surface of the cylindrical portion and the inner circumferential surface of the first annular groove are formed continuously by a machining operation including at least one of a cutting operation and a grinding operation.

13. The vane pump as recited in claim 1 , wherein the rotor includes a recess recessed radially inwards from an inner circumferential surface of the first annular groove, to a position on a radial inner side of the outside circumferential surface of the cylindrical portion.

14. The vane pump as recited in claim 1 , wherein the drive shaft includes an engagement shaft portion having a noncircular cross section, and the rotor includes an engagement hole having a noncircular cross section and engaging with the engagement shaft portion of the drive shaft.

15. The vane pump as recited in claim 14 , wherein the engagement shaft portion of the drive shaft has two opposite flat outside surfaces, and the engagement hole of the rotor has two opposite flat inside surfaces.

16. The vane pump as recited in claim 14 , wherein the vane pump is provided in a balancer device of an internal combustion engine, and the drive shaft is an extension of a balancer shaft of the balancer device.

17. The vane pump as recited in claim 1 , wherein a sliding contact area between the slide contact portion of the rotor and the inside wall surface of the second side wall of the housing is smaller than a sliding contact area between the outside circumferential surface of the cylindrical portion of the rotor and the inside circumferential surface of the

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Saga Koji
• Ohnishi Hideaki
• Watanabe Yasushi

Classifications

• F04C14/226

  by pivoting the cam around an eccentric axis · CPC title

• F01C21/0836

  comprising guiding means, e.g. cams, rollers · CPC title

• F04C2/3442 Primary

  the surfaces of the inner and outer member, forming the working space, being surfaces of revolution · CPC title

• F04C2240/20

  Rotors · CPC title

• F04C14/223

  using a movable cam · CPC title