Hitachi Automotive Systems Steering, Ltd.

Hiroki Imanaga

Yukio Uchida

Satoshi Muramatsu

A variable displacement vane pump and a power steering can secure a discharge flow rate when a steering wheel is turned, and restrict the discharge flow rate when the steering wheel is not turned. In the variable displacement vane pump and power steering system, a bypass line is formed. The bypass line causes a hydraulic fluid in a high pressure chamber of a control valve, which controls an eccentricity of a cam ring, to flow directly to a low pressure chamber side of the control valve. The hydraulic fluid flows directly to the low pressure chamber side of the control valve when the steering wheel is turned.

Variable displacement vane pump and power steering system

A variable displacement pump includes: a discharge opening formed at a position to confront a discharge region; a back pressure introduction groove formed on the suction region side; and a discharge side thin wall portion which is formed in the second housing, which has a recessed shape opened to the outside, which is disposed on the discharge region side, which is overlapped with the rotor in the radial direction, and which includes a smallest thickness portion having a smallest wall thickness of thicknesses each of which is an axial length between a bottom surface of the recessed shape and an axially inner side surface of the second housing, the smallest wall thickness being a smallest wall thickness of axial thicknesses of the second housing.

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Zama, Japan

Hiroki Imanaga