VARIABLE DISPLACEMENT PUMP

摘要

PROBLEM TO BE SOLVED: To provide a variable displacement pump largely reducing the discharged amount even when the rotational speed is increased. SOLUTION: This variable displacement pump comprises: a pump element 72 for changing the specific discharge amount according to a change in the eccentric amount of a cam ring 15; a metering orifice 23 provided to a discharge passage 38; a control valve 30 for controlling the movement position of the cam ring by controlling a pressure introduced into a first fluid pressure chamber 40 or a second fluid pressure chamber 42 which is formed in a pump element storage part 70; a high pressure introduction passage 73 for connecting a discharge port to a valve high pressure chamber 37; an intermediate pressure introduction passage 38a for connecting a valve intermediate pressure chamber 36 to the downstream side of the metering orifice; a branch passage 75 for connecting the high pressure introduction passage to a tank, a restriction 60 provided to the branch passage; and a variable damper orifice 20 which is provided on the discharge port side from the connection point of the branch passage in the high pressure introduction passage, and increases the flow passage area as the cam ring is moved in the direction to reduce the specific discharge amount. COPYRIGHT: (C)2010,JPO&INPIT