Patent ID: 8267218

Claim:
A power-operated steering assisting device comprising a rotation detector, a motor assembly, and a reduction and driving mechanism that are adapted to couple midway to a steering shaft of a steering wheel of a vehicle to realize assistance of steering by power provided by the motor assembly, wherein the steering shaft has an outer circumference to which bearings and ring covers are fit to coaxially mount the motor assembly and the reduction and driving mechanism, and the outer circumference of the steering shaft forming a toothed section at a portion thereof close to the reduction and driving mechanism, whereby driving is realized through engagement between the toothed section and an internal-toothed output ring of the reduction and driving mechanism; the rotation detector is mounted around the steering shaft at a predetermined location by an insulation sleeve and has a function to detect rotation of the steering shaft of the vehicle steering wheel and also to provide control of activating and deactivating the motor assembly; the motor assembly has an enclosure that is coaxially mounted around the outer circumference of the steering shaft by the bearings and the ring covers, and the motor assembly has a rotor that comprises a hollow tube centrally extending through the rotor and rotatably fit around the outer circumference of the steering shaft through needle bearings so as to allow for independent rotation of the rotor and the steering shaft, an end of the hollow tube being mounted to a gear, which is set in driving engagement with planetary gear modules of the reduction and driving mechanism; and the reduction and driving mechanism has an enclosure that is coaxially mounted around the outer circumference of the steering shaft by the bearings and the ring covers and is located adjacent to and behind the motor assembly and the enclosure defines an internal chamber in which the planetary gear modules are arranged in a cascade manner, of which a leading planetary gear module is set in driving engagement with the gear of the hollow tube of the rotator and a tailing planetary gear module is set in driving engagement with the toothed section of the steering shaft through the internal-toothed output ring; wherein upon detecting rotation of the steering shaft of the vehicle steering wheel, the rotation detector activates the motor assembly to operate the reduction and driving mechanism, so that through the engagement between the internal-toothed output ring and the toothed section of the steering shaft, the steering shaft is rotated and an assistance to steering operation is realized to provide an effort-saved operation of turning the steering wheel.