Patent ID: 8714298

Claim:
A pump apparatus arranged to supply a hydraulic fluid to a steering apparatus for a vehicle, the pump apparatus comprising: a pump housing including a pump element receiving portion; a drive shaft rotatably supported by the pump housing; a pump element received within the pump element receiving portion of the pump housing, and arranged to suck the hydraulic fluid by being rotated by the drive shaft, and to discharge the sucked hydraulic fluid; a cam ring disposed within the pump element receiving portion radially outside the pump element, and arranged to be moved so that a center of the cam ring is eccentric to a center of the drive shaft, and to vary an inherent discharge amount which is a discharge flow rate per one rotation of the pump element, based on an eccentric amount of the cam ring; a steering state sensing section configured to sense or estimate a steering angle, a steering angular speed or a steering angular acceleration, and to output the steering angle, the steering angular speed or the steering angular acceleration as a steering state sensing signal; and a solenoid configured to be controlled in accordance with a variation of a current amount controlled in accordance with the steering state sensing signal and a vehicle speed, and to control the eccentric amount of the cam ring, the solenoid configured to suppress the eccentric amount of the cam ring so as to decrease the inherent discharge amount with respect to the steering state sensing signal when a state in which the vehicle speed is equal to or greater than a first predetermined vehicle speed and the steering angle is equal to or smaller than a first predetermined steering angle continues during a predetermined time period, relative to the inherent discharge amount when the vehicle speed is smaller than the first predetermined vehicle speed, or the steering angle is greater than the first predetermined steering angle, wherein a control operation to suppress the eccentric amount of the cam ring is stopped when the vehicle speed becomes smaller than the first predetermined vehicle speed, or when the steering angle becomes greater than a second predetermined steering angle that is greater than the first predetermined steering angle during the control operation to suppress the eccentric amount of the cam ring.