Abstract: First and second fluid pressure chambers are formed in both sides of a movement direction of a cam ring swingably placed within a pump body. A spool of a control valve is moved due to a pressure difference between the front and back of a metering orifice. Fluid pressures of the fluid pressure chambers are controlled. The cam ring is swung. Further, a solenoid for giving thrust in an axial direction thereof to the spool of the control valve and electronic control device for controlling driving of the solenoid are provided. The electronic control device has a steering sensor and determines a steering direction based on a signal from the steering sensor and also calculates a steering speed to the steering direction and controls a driving current of the solenoid in response to this steering speed and changes a discharge flow rate of a pump.

Abstract: First and second fluid pressure chambers are formed in both sides of a movement direction of a cam ring swingably placed within a pump body. A spool of a control valve is moved due to a pressure difference between the front and back of a metering orifice. Fluid pressures of the fluid pressure chambers are controlled. The cam ring is swung. Further, a solenoid for giving thrust in an axial direction thereof to the spool of the control valve and electronic control device for controlling driving of the solenoid are provided. The electronic control device has a steering sensor and determines a steering direction based on a signal from the steering sensor and also calculates a steering speed to the steering direction and controls a driving current of the solenoid in response to this steering speed and changes a discharge flow rate of a pump.

Abstract: In a method of controlling a power steering system, which controls a steering force in accordance with an engine revolution when no vehicle velocity signal is supplied, after the engine revolution becomes a first predetermined value or more, and subsequently becomes a second predetermined value or less and a third predetermined value or more, the steering force is controlled in accordance with the engine revolution.