Hitachi Automotive Systems, Ltd.

Satoshi Nonaka

Makoto Kimura

Makoto Tada

Shigeaki Yamamuro

Jun Soeda

Hiroyoshi Gomi

Provided is a variable displacement vane pump which is capable of reducing fluctuation in discharge rate. In the variable displacement vane pump, a first straightening vaneclosest to one end-side openingof a discharge passageamong a plurality of straightening vanesandarranged within the discharge pressure chamberis located so as not to face a communication holeof a pressure plate

Variable displacement vane pump

A variable displacement pump including a drive shaft, a cam ring eccentrically moveable with respect to an axis of the drive shaft, and a solenoid drivingly controlled on the basis of variation in electric current amount to be supplied to the solenoid which is controlled in accordance with an operating condition of a vehicle. The solenoid is configured such that a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is smaller is reduced as compared to a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is larger.

Variable displacement pump and power steering apparatus using the variable displacement pump

A pump apparatus including a pump housing, a drive shaft, a cam ring movably disposed in the pump housing, a pump element disposed within the cam ring and rotationally driven by the drive shaft to vary a specific discharge quantity which is a discharge quantity of the working oil per one rotation of the pump element in accordance with variation in eccentric amount of the cam ring with respect to the drive shaft, and a solenoid which is drivingly controlled on the basis of a steering condition and a vehicle speed and operated to control the eccentric amount of the cam ring. The solenoid is controlled to execute a flow rate reduction control during cranking of an engine of the vehicle in which the cam ring is allowed to move in such a direction as to reduce the specific discharge quantity.

Pump apparatus and control method for controlling the pump apparatus

A variable displacement pump includes: a rotor mounted in a body; a cam ring mounted radially outside of the rotor, and arranged to move with a change in an eccentricity of the cam ring with respect to the rotor, wherein change of the eccentricity causes a change in a specific discharge rate; and an electromagnetic actuator arranged to actuate the cam ring for regulating the eccentricity. During control of operation of the electromagnetic actuator, a first response is set slower than a second response, wherein the first response is a response of movement of the cam ring to a change of an input signal in a direction to request a decrease in the specific discharge rate, and the second response is a response of movement of the cam ring to a change of the input signal in a direction to request an increase in the specific discharge rate.

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Atsugi, Japan

Satoshi Nonaka