The dynamic performance affected by the axial magnetic force for a DVD spindle motor

The axial magnetic force induced by rotor and stator is an important performance index to affect the dynamic characteristic on a high-precision DVD spindle motor design. In this research, the axial magnetic forces are calculated at varying relative heights between rotor and stator by 3D finite element method (FEM), and compared with the experimental data. Based on the results of simulation and measurement of the axial magnetic forces, the dynamic vibration could be apparently improved and decreased from 76.7 to 3.85 mg at 6000 rpm with disc by a variation of relative height on a DVD spindle motor. The torque constant and running current are also applied as performance indices to evaluate dynamic performance in the paper.