Hitachi Automotive Systems Steering, Ltd.

Norikazu Kumasaka

Satoshi Muramatsu

Yukio Uchida

Masaaki Iijima

Yoshiaki Kido

Yutaka Ogiwara

Masaaki Aoki

A variable displacement vane pump is provided. This pump includes a pump housing including, a driving shaft, a rotor, a plurality of vanes, a cam support surface, a cam ring, an intake port formed at the pump housing, a discharge port formed at the pump housing, and a cam ring control mechanism disposed at the pump housing and configured to control an eccentric amount of the cam ring with respect to the rotor. The cam support surface is formed in such a manner that a shortest distance between the cam support surface and a reference line decreases from a second confining region side toward a first confining region side, and the cam ring is formed in such a manner that a cam profile radius change rate decreases first and then increases again on the second confining region side when eccentric amount of the cam ring is maximized.

Variable displacement vane pump

A variable displacement vane pump includes a notch portion which is a flow path provided to extend from an initiating end of a discharge port towards a terminating end side of a suction port. The notch portion is formed so that a sectional area of the flow path is smaller than a sectional area of the discharge port at the initiating end thereof and that a length of the flow path in a circumferential direction is 1.5 pitches or larger. The terminating end of the suction port is a point where the vane in the suction area last overlaps the suction port. The initiating end of the discharge port is a point where the vane departed from the suction area first overlaps the discharge port. One pitch is a distance defied in the circumferential direction between adjacent vanes of the plurality of vanes.

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Atsugi, Japan

Norikazu Kumasaka