Abstract: An electric power assisted steering system is disclosed in which a torque demand signal (8) is generated and applied to an electric motor (1) operatively connected to a steering mechanism (5) in order to assist a driver of the vehicle when steering the vehicle. The torque demand signal (8) includes a damping component that is dependent upon a measurement of torque T carried by the steering mechanism and a measurement of the angular velocity o) of the steering mechanism. The torque produced by the motor (1) is not obtrusive during “hands-on” manoeuvres but provides enhanced damping in other manoeuvres such as a steering flick.

Abstract: An electric power assisted steering system is disclosed in which a motor (1) is adapted to provide, an assistance torque to an output-shaft (12) through a worm gear (13) and wheel gear assembly (11) and a biasing means (14) is provided which biases the shaft carrying the worm gear (13) into engagement with the shaft carrying the wheel gear (11). The biasing means (14) may comprise a spring member provided between the gearbox housing and the bearing (9) supporting the free end of the worm gear shift, or a torsion spring adapted to act upon the bearing assembly.