Steering system for vehicles

Claim 1

Power assisted steering apparatus for a vehicle having wheels comprising: manually operated steering means including: a steering column; a steering wheel associated with said steering column and arranged for manual operation; and means for transmitting to the vehicle wheels a torque applied to said steering wheel and to said steering column; and electrical drive means associated with said manually operated steering means and which comprises: a brushless motor arranged to provide selectable axial rotation of said steering column and loosely coupled thereto, thereby to not interfere with manual steering when said electrical drive mans in inoperable; means for driving said brushless motor; computerized control means for activating said means for driving in accordance with predetermeind variable parameters and further in response to the application to said steering wheel of a turning force which causes application to said steering column of a torque of at least a predetermined magnitude; means, associated with said computerized control means, for sensing the torque applied to said steering column; and means, forming part of said computerized control means and adapted to receive an input from said means for sensing torque, for preventing operation of said brushless motor when the torque applied via said steering wheel is less than a predetermined threshold value, and wherein said brushless motor is a DC brushless motor having a rotor formed integrally with said steering column.