| 摘要 |
PURPOSE: To obtain the magnet of a motor in which the strength against heat and mechanical shock is improved by forming a number-of-revolutions detecting magnetizing unit of a combustible bonded magnet. CONSTITUTION: An annular magnet 1 has an upper drive magnetizing part 1a opposed at a predetermined gap to the salient pole of a stator core 9 at the inner periphery, and a lower number-of-revolutions detecting magnetizing part 1b adjacent to a magnetic detecting element 12 mounted on a board 6. The part 1a is circumferentially magnetized, and the outer periphery of the part 1b is finely magnetized circumferentially to detect the number of revolutions. The parts 1a and 1b are formed of separate members. The part 1b is formed of a flexible bonded magnet in which magnet powder is dispersed in synthetic rubber, natural rubber, or elastomer. As a result, the number-of- revolutions detecting magnetizing part has sufficient flexibility, and the strength against heat and mechanical impact can be improved. |
