Patent ID: 8607258

Claim:
A clamping device of a spindle motor, characterized by: a case configured to rotate with a rotation shaft of the spindle motor and configured to clamp a disk of the spindle motor; a plurality of arms, wherein each arm of the plurality of arms comprises a body having a distal end positioned at a lateral outer portion of the case to contact an inner surface of a center hole of the disk, a pair of disengagement prevention rails extensively formed with the body, and a support protruder formed between the disengagement prevention rails; and an elastic member coupled to the support protruder, the elastic member elastically supporting each arm of the plurality of arms toward the lateral outer portion of the case; wherein the case has a plurality of inclination portions and a plurality of planar portions; wherein each inclination portion is formed at an inner surface of an upper portion of the case; wherein an upper face of each disengagement prevention rail is in contact with an inclination portion of the plurality of inclination portions, respectively, when disk is coupled with the body; wherein each planar portion of the case is connected to an inclination portion of the plurality of inclination portions and is parallel to the remaining inner surface of the upper portion of the case other than the inclination portions; and wherein each inclination portion of the plurality of inclination portions comprises an inclination surface whose thickness tapers off as it approaches the lateral inner portion of the case, thereby allowing the upper face of the disengagement prevention rail with which it is in contact to depress upon insertion of the disk into the spindle motor.