Hitachi Automotive Systems, Ltd.

Hitachi Automotive Systems Steering, Ltd.

Masaaki Iijima

Yukio Uchida

Satoshi Muramatsu

Norikazu Kumasaka

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 vane pump includes a vane cam mounted in a recess of a rotor, and configured to move with eccentricity with respect to an axis of rotation of the rotor. A cam port is formed in a surface of a pump body facing the vane cam, and configured to hydraulically communicate with the recess of the rotor. The vane cam includes an outer peripheral surface configured to contact a proximal end of each of vanes, and configured to cause projection of the vanes along with rotation of the rotor. The vane cam hydraulically separates the proximal end portion of a first slot in a suction region from the proximal end portion of a second slot in a discharge region.

Vane pump

A vane pump includes a plurality of vanes and a vane cam. Each of the vanes is housed in a corresponding one of multiple slits in an outer periphery of a rotor in a manner of being capable of protruding from, and retracting in, the slit. Each of the vanes has both end faces formed into curved surfaces in a plane perpendicular to a rotational axis of the rotor. The vane cam is disposed in contact with an end portion of the rotor such that an outer peripheral surface thereof contacts inner peripheral side end portions of all vanes to thereby forcedly make the vanes protrude and retract. The vane cam is movable so as to vary an amount of eccentricity relative to a drive shaft.

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Maebashi, Japan

Masaaki Iijima