Patent ID: 7010990

Claim:
A detecting apparatus comprising: a plurality of signal generating devices each generating a signal whose magnitude varies periodically in accordance with a positional change of a rotating shaft, which is a base for rotation of a rotating body and whose position is offset when force is applied thereto, and in accordance with a rotational state of the rotating body, the signal generating devices being disposed at predetermined positions such that phases of the generated signals are different; a characteristic amount detecting device detecting a characteristic amount corresponding to an amount of positional offset of the rotating shaft from a rotational axis of the rotating shaft, on the basis of the signals generated by the plurality of signal generating devices; and a moment detecting device detecting a moment applied to the rotating shaft on the basis of the characteristic amount detected by the detecting device, and on the basis of a relationship which is determined in advance on the basis of a shaft stiffness of the rotating shaft and the characteristic amount which varies in accordance with the positional offset of the rotating shaft.