| 摘要 |
PURPOSE:To make an index magnet unnecessary by a method wherein a notch is provided on the side surface of a rotor yoke while an index signal is outputted by a magnetism detecting element utilizing flux leaked through the notch. CONSTITUTION:A notch 11 is formed by notching the side surface of a rotor yoke 2. The leakage flux of a driving magnet 1 through the notch 11 is detected by a magnetism detecting element 3 through Hall effect, for example, to output an index pulse signal from the magnetism detecting element 3. In this case, the pulse width of the index signal is specified by the width of the notch 11. The index signal is outputted by the magnetism detecting element utilizing the leakage flux through the notch 11 in such a manner. The plantation of an index magnet becomes unnecessary whereby the reduction of manufacturing cost as well as the improvement of the assembling property of the title motor may be contrived. |
