Patent ID: 6298940
Filing Date: 2001-10-09
Classification: B62D

Abstract:
A power steering system for a motor vehicle, comprising:a manual steering handle;a hydraulic servomotor which operates steerable vehicle wheels;a servo valve which operates the servomotor, said servo valve having two control parts which are rotatable relative to each other;a spring system which biases said control parts into a normal position relative to each other;an actuator which is directly or indirectly coupled with the control parts of the servo valve, said actuator being operable to adjust a relative angular position between the control parts;an angle sensor which is coupled directly or indirectly with the control parts of the servo valve, said angle sensor detecting the relative angular position between the control parts;a desired steering angle value sensor which senses a desired steering angle based on a position of the steering handle;an actual steering angle value sensor which senses an actual steering angle based on a position of the steerable vehicle wheels; andan automatic control arrangement which operates the actuator as a function of a comparison of the desired steering angle and the actual steering angle, and as a function of the relative angular position between the control parts so as to rapidly implement a desired steering angle change and counteract adjustment of the servomotor by lateral wheel forces.