Patent ID: 6230839
Filing Date: 2001-05-15
Classification: B62D

Abstract:
A servo-assisted steering system with hydraulic servo-assistance which is used for motor vehicles, comprising:a steering shaft which is provided with a steering wheel, said steering shaft being connected via a torsion spring with an input member of a steering gear,an output member of the steering gear which is connected with wheels of the vehicle which are to be steered,two work chambers of a servo motor of a hydraulic servo-assistance device which are pressurized by a servo pump via a steering valve when there is a relative rotation of the steering shaft with respect to the input member,at least one first sensor for detecting one of a rotation angle or a torque which is arranged on the steering shaft,a second sensor for detecting a steering angle which is arranged on one of the output member or the input member,a returning device for returning the steering gear and the wheels to be steered to a predetermined position after the steering wheel is released following a steering process,a common electronically-controlled electromagnetic valve which controls the amount and the direction of the hydraulic servo-assistance as well as the return of the wheels to be steered, anda bypass valve which is arranged between the steering shaft and the input member of the steering gear.