| 摘要 |
PROBLEM TO BE SOLVED: To decrease noise by restraining oscillation of a flat surface of a motor case and increase an oscillation frequency from a frequency being offensive to a person to a high frequency which is difficult for a person to hear. SOLUTION: The side surface of the motor case is formed in a polygonal shape which continuously integrates a flat side surface portion with a corner portion positioned at the corner portion between the flat side surfaces. A field magnet having an outer periphery surface of which the shape approximately meets the shape of the inner periphery surface of the motor case has a magnet side surface portion and a magnet corner portion, and a rib on the outer periphery surface of the magnet side surface portion. At least the rib of the magnet is brought into contact with the inner periphery surface of the motor case while the magnet side surface except the rib has a shape with a small gap or a shape which is not affected at least by the pressure force is press-attached to the motor case inner side. COPYRIGHT: (C)2009,JPO&INPIT
|
