| 摘要 |
In a brushless motor, a projected annular portion is formed in a central portion of a rotor frame and the projected annular portion has a bore that includes a small-bore portion and a large-bore portion. A length L1 of the small-bore portion is in a range of Dx0.05<=L1<=Dx0.20, where D represents the diameter of the shaft. An axial length L2 of the projected annular portion is arranged to satisfy L2>=L1x2. Thus, the brushless motor realizes a small and thin construction and has a high deflection precision as well as high productivity. |
