| 摘要 |
PROBLEM TO BE SOLVED: To provide a spindle motor, where the shock resistance required in a notebook type personal computer or the like and the reliability can be raised, by optimizing the structure of the screw hole or its periphery for stopping a clamper to the top end face of a rotary shaft. SOLUTION: In a spindle motor 1 corresponding to a 2.5-inch disk, as ball bearings 5 and 6, the largest ones which are tolerable when viewed from the outside dimension D2 of a disk guide 76 are used, so they are of high shock resistance by that amount. Moreover, when it is defined that the thickness of the rotary shaft at the section where a screw hole 75 to stop a clamper 100 is made is t and that the minor diameter of a screw hole 75 is D at the top end part of the rotary shaft 71, it is arranged so that the ball bearing 6 may not be transformed by the stress at the time of having fixed the screw 101, arranging it such that t and Do/satisfy the formula [t>=Do/2]. |
