Variable displacement vane pump

摘要

A variable displacement vane pump includes a first and a second fluid pressure chamber (31,32) where the cam ring (4) is made eccentric to the rotor (2) by a pressure difference between the first and the second fluid pressure chamber (31, 32), a control valve (21) for controlling a pressure of the first and the second fluid pressure chamber (31,32) so that an eccentric amount of the cam ring (4) is reduced to be small with an increase in a rotation speed of the rotor (2), a pressure applying means (36) for applying a pressure to the cam ring (4) in a direction of increasing the eccentric amount all the time, and a cam ring movement restricting means (12) for defining a minimum eccentric amount of the cam ring (4) by restricting the movement of the cam ring (4) in a direction of decreasing the eccentric amount.