ROTATING BODY, ROTATING BALANCER AND BALANCE ADJUSTING METHOD

PROBLEM TO BE SOLVED: To obtain a rotating body, a rotating balancer and a balance adjusting method in which an imbalance can be canceled without a need of a special apparatus and a complicated processing operation and without a restriction on a special structure. SOLUTION: A liquid thermosetting resin as a balance material 84 is sealed into a ring-shaped part 82a, for balance, inside a ring-shaped member 82 in a rotating balancer 80. The rotating balancer 80 is situated in the center gap between hard disks 60. A rotating body which contains a rotor 20 is turned at a speed of rotation which is higher than the natural frequency of a vibration in its radial direction while its rotation axial line is used as the up-and-down direction. When an imbalance is generated in a rotating body which does not contain the balance material 84, the balance material 84 flows, and an amount which can cancel the imbalance is unevenly distributed in a position in the circumferential direction which can cancel the imbalance. The whole balance material 84 is hardened by heating.