Reduction of the Power Consumption of a Stepping Motor for Driving the Hands of Wristwatches

Abstract

This paper reports on two methods that achieve a reduction in the power consumption of a stepping motor for driving the hands of wristwatches. The first of these methods involves the enhancement of the magnetic bonding between the rotor, comprised of a dipolar permanent magnet, and the stator. The gap between the rotor and the stator has been narrowed for this purpose. The second of these methods involves suppressing the increase of the detent torque, which occurs in association with the former method. The portion of the stator that generates this detent torque has been thinned on both sides to adjust the thickness for the same reason.