| 摘要 |
<p>A brushless motor (3) is provided with a rotor (22) having a magnet (33), and a stator (21) having teeth (27) facing the magnet (33) through an air gap (45). At the leading ends of the teeth (27), a plurality of auxiliary grooves (20) which face the air gap (45) are formed. A ratio W/S of the groove width (S) of the auxiliary groove (20) and the opening width (W) of an opening section (46) between the adjacent teeth (27) satisfies inequalities of 0.9=W/S=1.1. A ratio ?s/?w of an angle (?w) between the center (M<SUB>1</SUB>) of the opening section (46) and the center (M<SUB>2</SUB>) of the auxiliary groove (20) and an angle (?s) between the centers (M<SUB>2</SUB>) of the adjacent auxiliary grooves (20) is set within a range of 0.66=?s/?w=0.965.</p> |
