Patent ID: 7187153

Claim:
A motor-driven power steering apparatus having a single brushless motor as an electric motor, having plural phases of coil windings wound around a stator core comprising a plurality of exciting phases, arranged to sequentially supply a driving current to the exciting phase of each of the coil windings on the basis of a rotational position of a rotor detected by a rotational position detecting sensor, and being capable of driving the electric motor, when converting rotation of the electric motor into a stroke of a rack shaft by a power transmission mechanism, and when assisting steering of a tire wheel connected to the rack shaft, wherein a plurality of rotational position detecting sensors are provided in the single electric motor, each sensor arranged and constructed to provide complete control of the single motor without cooperation from another sensor, and during an abnormality in any one rotational sensor, the electric motor is drivable by using a detected result of any other one rotational position detecting sensor.