VARIABLE DISPLACEMENT VANE PUMP

摘要

A variable displacement vane pump is provided with: a control orifice 104 for applying resistance to the flow of hydraulic oil discharged from a pump chamber 6; a flow rate control valve 102 for controlling, depending on the pressure difference across the control orifice 104, the flow rate of the hydraulic oil discharged from the pump chamber 6; a variable control valve 103 operated by hydraulic oil which has passed through the control orifice 104 and controlling the difference between pressure in a first hydraulic pressure chamber 15 and pressure in a second hydraulic pressure chamber 16, thereby controlling the amount of eccentricity of a cam ring 4 relative to a rotor 2; and a return passage 42 connected to the flow rate control valve 102 and returning a part of the hydraulic oil, which is discharged from the pump chamber 6, to a suction passage 40.