| 摘要 |
PURPOSE:To form an inexpensive DC brushless motor adapted for a cooling fan drive source by providing a middle pole which is disposed at the intermediate of pole shoes and which is projected toward a stator yoke. CONSTITUTION:Middle poles 11, 11' are planted on the outer periphery of a stator yoke 8 to radially project and to be disposed between pole shoes 5a and 5b. The air gap length between the poles 11, 11' and a permanent magnet 3 is equal to the air gap between the shoes 5a, 5b and the magnet 3, and the air gaps between the ends of the pole shoes and the ends of the middle poles are equally provided. Further, a magnetic detector 9 is provided in the air gap at the end of the pole shoe, thereby enabling self-starting. In this manner, inexpensive DC brushless motor which is adapted for a cooling fan drive source and which has less number of parts can be formed. |
