Power assisted steering for vehicles

摘要

A power assisted steering functioning purely by means of an electric motor for motor vehicles has two brake discs (27, 38), coaxial with the steering column (10), which are driven at constant speed in opposite directions of rotation by an electric servo motor (12). A brake device (41), acting alternatively on either of the brake discs (27, 38) is coupled to the steering column (10), which device, as a function of the steering moment acting on the steering column (10), generates a brake torque on the brake disc (27, 38) rotating in the effective direction of the said steering moment, as a result of which the brake device (41) rotates in the same direction as the steering column (10) relative to the servo motor (12), thereby generating a torque acting in the same direction on the steering column. Such a power steering is compact and easily assembled and does not require any safety device such as known electrical steering boosters in order to avoid unwanted self-steering. In the event of a defect of the power assistance unit only a low resistance moment occurs, so that the vehicle can still be steered with a tolerable effort (Fig. 1). <IMAGE>