| 摘要 |
PROBLEM TO BE SOLVED: To provide an outer rotor type brushless motor which is reduced in weight and improved in efficiency. SOLUTION: A rotor 20 includes a bottomed, cylindrical rotor body 21, a back yoke 22 which is attached to the inner peripheral surface 21c1 of the rotor body 21 and is formed by stacking a plurality of yoke core materials 22a made of a thin-plate magnetic material, and a magnet 23 which is attached to the inner peripheral surface 22b2 of the back yoke 22 and has a plurality of magnetic poles different in polarity from each other that are formed alternately in the circumferential direction. The back yoke 22 has an annular back yoke body 22b, and projected extensions 22c that are formed circumferentially at intervals to project radially outward from the outer peripheral surface of the back yoke body 22b in the same number as the number of magnetic poles. A boundary formed between adjacent magnetic poles of the magnet 23 is located radially inside the extension 22c formed on the back yoke 22. COPYRIGHT: (C)2010,JPO&INPIT |
