| 摘要 |
PROBLEM TO BE SOLVED: To provide a spindle motor which can decrease the side-runout of a rotated unit mounted in the hub of a rotor. SOLUTION: In this spindle motor, a hub 33 provided in a rotor has a rotated unit mounting surface 38 and a fitting protruded part 39 protruded from a central part of this mounting surface, one surface of a polygon mirror having a center hole is superposed in the rotated unit mounting surface 38, also the center hole is fitted to the fitting protruded part 39, this polygon mirror is mounted in the hub 33. Here, in a volute pattern-shaped cutting groove 45 provided with a volute pattern-shaped ridge line part 47 over a total unit of the rotated unit mounting surface 38, a fine cutting pit 46 is innumerably provided with a fixed space apart. |
