| 摘要 |
A torque detection apparatus includes a resolver having a rotor core and a stator core, and a computation unit having a multiple rotation amount computation section, a multiple rotation amount accumulation section, and an abnormality determination section. The rotor core moves along the axial direction of a steering shaft in response to rotation of the steering shaft. Based on a change of a transformation ratio of the resolver caused by a change of the relative positions of the rotor core and the stator core along the axial direction due to movement of the rotor core, the multiple rotation amount computation section computes a first multiple rotation amount N of the steering shaft. The multiple rotation amount accumulation section detects the switchover point of the absolute angle theta 0 when the steering shaft is rotated a single rotation, and computes a second multiple rotation amount N' by accumulating the number of detection of the switchover point. The abnormality determination section determines whether there is an abnormality in the torque detection apparatus based on whether the first and second multiple rotation amounts N, N' are equal to each other (N=N').
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