| 摘要 |
PURPOSE:To simplify the magnetizing step and to reduce the manufacturing cost of a disc type brushless motor by forming poles for detecting a frequency on the outer periphery of a main pole of a field magnet. CONSTITUTION:A magnetized yoke 14' has grooves 17' perpendicular to the end face 16' of a cylinder 15' formed of a ferromagnetic material at the center, and an exciting coil is wound in the grooves 17'. Many grooves 19 of fine equidistant pitch for forming poles for detecting a frequency are formed on the outer periphery of the end face 16'. When a current is flowed to the exciting coil by using the yoke, a field magnet which has 4-main poles having N- and S-poles and the poles for detecting the frequency is obtained. |
