| 摘要 |
PROBLEM TO BE SOLVED: To suppress the rotational vibration caused by eccentricity or mass eccentricity of a disk. SOLUTION: Plural magnetic balls 46 are arranged freely rollable in an annular ball rolling chamber 41c which is formed on a lower clamper 41 constituting a part of a disk clamper 40, and also a magnet 50 is fixedly arranged, facing opposite to an opening part 41d opened at the upper part of the lower clamper 41, and only when the vibration due to the rotation of the disk D is small, plural magnetic balls 46 arranged in a annular ball rolling chamber 41c are taken out to the outside of the disk clamper 40 by the electromagnetic force through the opening part 41d and attracted to the magnet 50.
|
