| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic balancing device capable of maintaining balancing capability satisfactorily and reducing noise generated during its operation, and to provide a rotating device and a disc driving device. SOLUTION: This automatic balancing device is provided with a case 2 storing a magnetic fluid 9 and a plurality of spherical balancers 11 formed a non-magnetic materials. The case 2 has an opening at its upper part and a cover 1 is mounted in the opening to constitute a housing 5. An annular magnet 12 provided with an annular back yoke 13 is arranged at an outer peripheral part of the housing 5. Since the magnetic fluid 9 is attracted to the magnet 12 and the balancers 11 move on the outer peripheral side of the housing 5 smoothly at least when the housing 5 rotates, it is possible to reduce the noise generated by the mutual contact of solids observed in a conventional automatic balancing device. COPYRIGHT: (C)2008,JPO&INPIT
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