| 摘要 |
In the back pressure groove structure of a variable displacement vane pump comprising a rotor rotatably contained in a pump housing and having a plurality of vane grooves arranged radially and equidistantly in a circumferential direction, a cam ring is arranged in the pump housing in a movable and displaceable manner, fitted into the pump housing to form a pump chamber with an outer peripheral portion of the rotor and applied with an urging force to provide a maximum volume of the pump chamber. A side plate is contained in the pump housing in a non-rotatable manner, slidably contacting with one sides of the rotor and the cam ring and having back pressure grooves communicating with the vane grooves. A cover plate closes an opening of the pump housing, slidably contacting with other sides of the rotor and the cam ring and having a back pressure groove communicating with the vane grooves, the back pressure grooves of the side plate communicate with a high pressure side and are divided back pressure grooves obtained by dividing an annular back pressure groove into a pump suction side groove and a pump discharge side groove. The back pressure groove of the cover plate is an annular back pressure groove or a C-shaped back pressure groove obtained by closing the annular back pressure groove at one of a pump suction side portion and a pump discharge side portion into which the annular back pressure groove is virtually partitioned.
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