The acoustic noise characteristics of HDD due to the structural excitation of spindle motor

HDD structure is excited by the dynamic motion of disk-spindle motor components. Those excitations which are generated from stator, magnet rotor, bearings and disks, are transmitted through motor spindle and flange to HDD cover and base. The operational deflection shape measurement can show the structural elicitation patterns at the most influential frequency of the acoustic noise level. One of those components is the axial excitation along spindle, and the other is the local orbital excitation at the contact area of motor flange and base. In order to make a reduction of those structural transmission excitations, the structure of spindle motor should be modified to the direction of reinforcement at transmission path. Some excitation of spindle motor component carrying out essential function is unavoidable. So it is the efficient may of HDD noise improvement to control the structural transmission of excitation.