| 摘要 |
A power steering apparatus has an electric motor 19 assisting in steering on the basis of the steering angle of a steering wheel 1, and is equipped with: a first detection gear 26 that has a magnet 46 and rotates along with the rotation of the steering wheel; a second detection gear 27 that has a magnet 47 and rotates along with the rotation of the first detection gear; first and second mark portions 69, 70 that are provided to the respective gears so as to show the pole positions of the gears, and are arranged in predetermined positional relation with respect to each other when the gears are installed on a steering angle sensor; first and second MR elements 59, 60 that detect the rotational angles of the gears from variations in the magnetic fields of the gears; and an absolute steering angle calculation circuit 68 that calculates a steering angle from each of the rotational angles. Thus, it is possible to maintain safe drive control even in the event of failure in the calibration function of correcting the output value of the steering sensor. |
