GB1341051A - Electronic controlled power steering for vehicles - Google Patents

Abstract

1341051 Power assisted steering J H APPLEBY 22 Aug 1972 [25 May 1971] 16774/71 Heading B7H An electrically operated power assisted steering mechanism includes a torsion bar c, the twist in which is converted into axial motion which varies a resistance and hence a current, this current then being used to control a switching device which in turn controls the torque output from an electric motor (not shown) which is directly coupled into the vehicle steering. As described the steering shaft consists of two tubular parts b, d interconnected by a torsion bar c. A pair of rollers f, g on the tubular part d engage an axial slot in a sleeve j and a roller e on the tubular part b engages an inclined slot in the sleeve j, the arrangement being such that when a torque is applied to the steering wheel a the twist in the torsion bar c is converted into axial movement of the sleeve j. A flange h is located between rollers k, l on the ends of levers m, n which are pivoted to a fixed plate s. When no torque is applied the levers m, n are held in contact with a stop t by a spring u and when a torque is applied to the steering wheel a one of the levers m, n is moved, depending on the direction of steering. Lever m carries the track of a variable resistance o and lever n carries the slider so that movement of the flange h in either direction alters the resistance o. The current in the resistance o controls an oscillator (not shown) which in turn controls the torque output of the electric motor coupled to the vehicle steering. A switch p which is operated if either of levers m, n is moved switches on the power to the motor and a by-pass switch q supplies full power to the motor when maximum torque is applied. Switch r is a reversing switch which controls the direction of the motor depending on the direction of steering.