| 摘要 |
PURPOSE:To obtain an inexpensive detector with high resolution by fitting a rotational position detecting mechanism like an encoder through a speed increasing mechanism connected to the rotary shaft of an electric motor. CONSTITUTION:A gear 2 (number of teeth of gear 2b < number of teeth of gear 2a) is fitted as the speed increasing mechanism to the rotary shaft of the electric motor on the opposite side from its driving shaft and the rotation of the output side of the gear 2 is increased in speed. This speed-increased rotation is detected by the encoder 3. Further, a sensor 4 fitted on the rotary shaft of the electric motor 1 detects a member 4a arranged on the rotary shaft and generates the origin signal of the electric motor shaft. The origin position of the electric motor 1 is corrected with this origin signal and a rotational position detection signal is obtained from output pulses based upon the rotation of the electric motor 1 detected by the encoder to detect the rotational position of the electric motor 1. Thus, the number of output pulses per turn of the electric motor 1 increases, so the resolution can be improved even when a rotational position detecting mechanism put on the market is employed.
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