| 主权项 |
1. A variable displacement vane pump, comprising:
a pump housing including a pump-element housing portion; a driving shaft rotatably supported by the pump housing; a rotor provided inside the pump housing so as to be rotationally driven by the driving shaft, the rotor including a plurality of slots arranged in a circumferential direction, which is a direction about a rotation axis of the driving shaft; a plurality of vanes provided in the plurality of slots so as to be projectable therefrom and retractable therein; a cam ring formed so as to have an annular shape, the cam ring being provided so as to be movable inside the pump-element housing portion, the cam ring forming a plurality of pump chambers on an inner circumferential side in cooperation with the rotor and the plurality of vanes; an intake port formed in the pump housing, the intake port having an opening in an intake region, in which volumes of the plurality of pump chambers increase along with the rotation of the rotor; a delivery port formed in the pump housing, the delivery port having an opening in a delivery region, in which the volumes of the plurality of pump chambers decrease along with the rotation of the rotor; a pair of sealing grooves formed on the pump-element housing portion so as to have openings oriented toward an outer circumferential surface of the cam ring in a radial direction, which is a radiation direction of the rotation axis of the driving shaft, the pair of sealing grooves being a first sealing groove and a second sealing groove formed on the intake port side with respect to the driving shaft so as to be separated away from each other in the circumferential direction; a pair of sealing members which are a first sealing member provided in the first sealing groove and a second sealing member provided in the second sealing groove; a pair of pressure chambers formed between the pump-element housing portion and the cam ring in the radial direction so as to be separated by the first sealing member and the second sealing member, the pair of pressure chambers being:
a first fluid-pressure chamber provided on a side on which a volume thereof decreases when the cam ring moves to a side on which an eccentricity of the cam ring increases, the first fluid-pressure chamber being configured such that a delivery pressure delivered through the delivery port is introduced so that a pressure in the first fluid-pressure chamber becomes higher than a pressure in a low-pressure chamber, which is a pressure chamber formed between the first sealing member and the second sealing member; anda second fluid-pressure chamber provided on a side on which a volume thereof increases when the cam ring moves to a side on which the eccentricity of the cam ring increases, the second fluid-pressure chamber being configured such that the delivery pressure delivered through the delivery port is introduced so that a pressure in the second fluid-pressure chamber becomes higher than the pressure in the low-pressure chamber; and a control valve configured to control the pressure in the first fluid-pressure chamber or the second fluid-pressure chamber. |
