Patent ID: 9239050
Filing Date: 2016-01-19
CPC Classification: F01C,F04C

Claim Text:
1. A vane pump configured as a fluid pressure supply source, the vane pump comprising: a cam ring having a cam surface formed on an inner periphery thereof; a rotor provided to face the inner periphery of the cam ring and to be driven to rotate relative to the cam ring; a plurality of slits formed in a radial shape in an outer periphery of the rotor; a plurality of vanes having respective base end portions inserted slidably into the slits such that respective tip end portions of the vanes slidably engage against the cam surface, wherein the base end portions of the vanes are opposite to the respective tip end portions; a side plate; a pump cover, wherein the side plate and the pump cover sandwich the rotor and the vanes; a plurality of pump chambers defined between the cam surface and the rotor by the vanes; a plurality of back pressure chambers defined between the respective base end portions of the vanes and the slits, the back pressure chambers configured to bias the vanes toward the cam surface; a plurality of back pressure grooves formed in end surfaces of the side plate and the pump cover against which the rotor is configured to slide, the plurality of back pressure grooves configured to communicate with the back pressure chambers as the rotor rotates; and a plurality of connecting grooves formed in the end surfaces of the side plate and the pump cover against which the rotor is configured to slide, the plurality of connecting grooves connecting the plurality of back pressure grooves that are adjacent in a circumferential direction of the rotor to each other, wherein a first connecting groove of the plurality of connecting grooves has a larger passage sectional area than a second connecting groove of the plurality of connecting grooves, the second connecting groove different from the first connecting groove, the first connecting groove communicates with a first back pressure groove of the plurality of back pressure grooves formed in the pump cover, the first back pressure groove is positioned in a suction region above a rotary center of the rotor so as to suction a working fluid into the pump chambers, the second connecting groove communicates with a second back pressure groove of the plurality of back pressure grooves formed in the pump cover, the second back pressure groove different from the first back pressure groove, and the second back pressure groove is positioned in another suction region below the rotary center of the rotor.