| 摘要 |
PURPOSE:To enhance the efficiency by circumferentially splitting the pole of an armature to form the first and second pole pieces, and forming the magnetically asymmetrically, thereby reducing the vacant circumferential angel of the poles of different polarity. CONSTITUTION:A permanent magnet ring is formed in a rotor 2, and a shaft 3 is journaled to the rotor. An upper yoke 9 has a flange 9b bent at the outer peripheral edge of a disc-shaped ring 9a, and poles 5, 6 bent at the inner periph eral edge are integrally formed. In this case, the poles 5, 6 are split and have a pair of relatively wide-width pole pieces 5a, 5b and narrow pole pieces 5b, 6b, extensions 5c are integrally extended from the split surfaces to form both magnetically asymmetrically. A lower yoke 10 is similarly formed. Thus, the naturally stopping position of an armature 11 at nonconducting time is displaced relatively in the rotating direction to avoid a starting dead point. |
