| 摘要 |
PURPOSE:To magnetize a main pole and a rotation detecting pole on a rotor in one step by forming many shallow grooves radially at a fine pitch on the entire circumference in addtion to deep grooves which perpendicular cross the end face of a cylinder formed of a magnetic material. CONSTITUTION:Deep grooves 17' which perpendicularly cross the end face of a cylinder 15' formed of a hollow magnetic material at the center is provided. Many grooves 19 are formed radially at a fine pitch on the entire cylinder between the adjacent grooves 17', and many projections 20 having narrow width are formed. Coils are inserted into the grooves 17' in 8 shape as shown by broken lines, a thin disc 4' made of a magnetic material is contacted with the end face 16'. When the coil is energized, poles N, N' and S, S' which operate as rotating speed detecting poles are magnetized in the relationship of N, N', S, S' in addition to the main poles N, S on one step. In this manner, the structure of a rotor for a motor can be simplified and the number of steps can be decreased. |
