| 摘要 |
PROBLEM TO BE SOLVED: To provide a spindle motor which reduces vibration and is free of rotor coming-off. SOLUTION: This spindle motor gains thrust force through the attractive force of an auxiliary magnet 16 installed on a fixed sleeve 2 and a ring plate 17 installed on a rotor 21. Even if the magnetic center of a main magnet 8 and the magnetic center of a stator core 7 are matched with each other, the rotor is not lifted off. When an impact which exceeds the thrust force is exerted, an insert 20 is brought into contact with the ring plate 17, and sure prevention of the rotor from coming off is realized. During the normal rotation, a gapΔd in the direction of the thrust is formed on the opposite faces of the ring plate 17 and the insert 20. By properly setting the gap so a lubricating fluid does not pass through the gap, the lubricating fluid is prevented from scattering. |
