Patent ID: 7149615

Claim:
An absolute steering angle detection device for an electric power steering device characterized by comprising: a steering wheel; a motor for assisting the rotation of the steering wheel; first detection means for torque detection for detecting the steering torque of the steering wheel to linearly output a first detection signal in dependence on the rotational angle of the steering wheel; second detection means for detecting the rotation of a motor which is driven in dependence on the rotation of the steering wheel to assist the rotation of the steering wheel, to linearly output a second detection signal having a frequency different from that of the first detection signal; first operation means for calculating rotational numbers of the motor based on the first and second detection signals and the rotational number of the steering wheel; first selection means for selecting an appropriate rotational number from the rotational numbers of the motor calculated by the first operation means; second selection means for selecting a rotational number of the steering wheel which corresponds to the appropriate rotational number selected by the first selection means; and second operation means for calculating an absolute steering angle based on the rotational number of the steering wheel selected by the second selection means and the first detection signal.