Patent ID: 7178625

Claim:
A steering actuator of an independent type steer-by-wire system comprising: a housing fixed to a vehicle body; an ultrasonic motor having a stator internally fixed to said housing and a rotator rotating relative to said stator when an electric current is applied; a steering rod having a first end and a second end, the steering rod penetrating through a center portion of said ultrasonic motor, the first end of said steering rod extending out of said housing for connection to a tie rod; and a movement conversion means operably associated with said steering rod for converting rotating movement of said ultrasonic motor into linear movement of said steering rod; wherein said movement conversion means includes: a ring gear having an inner peripheral surface, the ring gear being internally fixed to said housing; at least one planetary gear installed to said rotator of said ultrasonic motor by means of pins, said at least one planetary gear being engaged with the inner peripheral surface of said ring gear; a sun gear having an outer peripheral surface and an inner peripheral surface, the outer peripheral of the sun gear being engaged with said at least one planetary gear, at least one worm gear formed with the inner peripheral surface of said sun gear; and at least one rack formed at said steering rod, said at least one rack being engaged with said at least one worm gear.