Electrical power assisted steering
AssigneeTRW LucasVarity Electric Steering Ltd.
InventorMichael Appleyard
Life of this patent
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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 shaft, or a torsion spring adapted to act upon the bearing assembly.
Claims19
An electric power assisted steering system comprising a housing, an electric motor fixed relative to said housing and having a stator and a rotor, an input shaft operatively connected to said rotor, an output shaft operatively connected to a steering column, and a torque sensor adapted to produce an output signal indicative of torque in said output shaft, said motor being adapted to apply a torque to said output shaft dependent upon said output signal from said torque sensor through a worm gear provided on said input shaft which is adapted to mesh with a wheel gear operatively connected to said output shaft, wherein said steering system further comprises a first bearing means which supports said input shaft relative to said housing at its end distal from said motor and a leaf spring which is adapted to act upon said first bearing means to bias said input shaft towards said wheel gear.
Dependencies are inferred from the claim text.