| 摘要 |
PURPOSE: To provide a highly reliable brushless motor, by preventing the stickings of cutting powders and dusts to its driving magnet, and by eliminating the origins of its vibration and noise while eliminating the discrepancy between the magnetic centers of its driving magnet and stator core. CONSTITUTION: In a brushless motor, a hub 1 for mounting a magnetic disk thereon, a rotor yoke 2 made of a magnetic material which is fastened to the hub 1, a driving magnet 3 fastened to the yoke 2, and a stator core 7 disposed oppositely to the magnet 3 are provided respectively, and further, the rotation of the hub 1 is driven by the relative rotation of the magnet 3 to the stator core 7. The magnet 3 is an annular poly-pole magnetization magnet wherein the polarities of its magnetic poles neighboring in its circumferential direction are different from each other alternately. Also, in each boundary part between the different magnetic poles present in the outer peripheral part of the magnet 3, a groove 11 is formed in its axial direction, and the outline of the magnet 3 is so formed that its upper diameter is smaller than its lower diameter, and further, clearances C1, C2 are provided between the outer peripheral surface side of the magnet 3 and the inner peripheral surface side of the rotor yoke 2. |
