Variable displacement vane pump

Patent metadata

Field	Value
Publication number	US-2016010642-A1
Application number	US-201414766525-A
Country	US
Kind code	A1
Filing date	Feb 5, 2014
Priority date	Feb 22, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A vane pump includes a rotor, vanes, pump chambers, a suction port, and a discharge port. The side member has a first transition section and a second transition section. The first transition section is a section from an end point of the suction port to a start point of the discharge port. The second transition section is a section from an end point of the discharge port to a start point of the suction port. An angle between the start point and the end point of the suction port is set such that a pressurizing timing is offset from a depressurizing timing. The pressurizing timing is a timing at which one pump chamber starts to communicate with the discharge port from the first transition section, and the depressurizing timing is a timing at which another pump chamber starts to communicate with the suction port from the second transition section.

First claim

1 . A variable displacement vane pump used as a fluid pressure source, comprising:
a rotor that is configured to rotationally driven by motive power from a motive-power source; a plurality of slits radially formed so as to open to an outer circumference of the rotor; vanes slidably received in the respective slits; a cam ring having an inner circumferential cam face with which tip portions of the vanes are brought into sliding contact, the cam ring being capable of being made eccentric to a center of the rotor; a side member provided so as to be in contact with a side surface of the cam ring; pump chambers defined by the rotor, the cam ring, the side member, and the adjacent vanes; a suction port formed to have an arc shape on the side member in a region in which displacement of the pump chambers are expanded by rotation of the rotor, the suction port being configured to guide working fluid to be sucked into the pump chambers; and a discharge port formed to have an arc shape on the side member in a region in which displacement of the pump chambers are contracted by rotation of the rotor, the discharge port being configured to guide working fluid discharged from the pump chambers; wherein the side member has a first transition section and a second transition section, the first transition section being a section from an end point of the suction port to a start point of the discharge port, the second transition section being a section from an end point of the discharge port to a start point of the suction port, and wherein an angle between the start point and the end point of the suction port with respect to the rotor serving as a center is set such that a pressurizing timing is offset from a depressurizing timing, the pressurizing timing being a timing at which one pump chamber starts to communicate with the start point of the discharge port from the first transition section, the depressurizing timing being a timing at which another pump chamber starts to communicates with the start point of the suction port from the second transition section.

2 . The variable displacement vane pump according to claim 1 , wherein
the angle between the start point and the end point of the suction port with respect to the rotor serving as the center is greater than an angle between the start point and the end point of the discharge port with respect to the rotor serving as the center.

3 . The variable displacement vane pump according to claim 1 , wherein
when number n of the vanes is an odd number of five or more, an angle θ between the start point and the end point of the suction port with respect to the rotor serving as the center satisfies 180°−(360°/(2×n))−t 180°+(360°/(2×n))+t, with an angle corresponding to thicknesses of the vanes being indicated as t.

4 . The variable displacement vane pump according to claim 1 , wherein
when number n of the vanes is an even number of six or more, an angle θ between the start point and the end point of the suction port with respect to the rotor serving as the center satisfies 180°−t≦θ≦180°+(360°/n)+t, with an angle corresponding to a thicknesses of the vanes being indicated as t.

5 . The variable displacement vane pump according to claim 1 , wherein
an angle of the second transition section with respect to the rotor serving as a center is smaller than an angle of the first transition section with respect to the rotor serving as a center.

6 . The variable displacement vane pump according to claim 1 , wherein
the angle between the start point and the end point of the suction port with respect to the rotor serving as a center is set such that the pressurizing timing is offset from the depressurizing timing all the time regardless of an amount of eccentricity of the cam ring.

7 . The variable displacement vane pump according to claim 1 , further comprising:
a first fluid pressure chamber and a second fluid pressure chamber defined in an accommodating space on an outer circumference of the cam ring, the first fluid pressure chamber and the second fluid pressure chamber being configured to make the cam ring eccentric to the rotor by a pressure difference between the first fluid pressure chamber and the second fluid pressure chamber; and a control valve that is configured to operate in response to a pressure of working fluid guided from the discharge port, to control pressure of the working fluid in the first fluid pressure chamber and the second fluid pressure chamber to change the amount of eccentricity of the cam ring to the rotor, and to control a discharge flow amount of the pump.

Assignees

• Kayaba Industry Co Ltd

Inventors

• Akatsuka Koichiro
• Fujita Tomoyuki
• Kato Fumiyasu

Classifications

• F04C2/332

  with vanes hinged to the outer member and reciprocating with respect to the inner member · CPC title

• F04C14/223 Primary

  using a movable cam · CPC title

• F04C14/226

  by pivoting the cam around an eccentric axis · CPC title

• F04C2250/10

  of the inlet or outlet · CPC title

• F04C2/344 Primary

  with vanes reciprocating with respect to the inner member · CPC title