Modeling of Axial Magnetic Force and Stiffness of Ring-Shaped Permanent-Magnet Passive Vibration Isolator and Its Vibration Isolating Experiment

Magnetic suspension vibration isolators have attracted more and more attention in the field of semiconductor industry and high precision equipments. A novel ring-shaped permanent-magnet passive vibration isolator is mainly reported in this paper. An analytical expression of axial magnetic force of the isolator is derived and validated by the finite element analysis and experiment. It proves that the analytical expression is efficient. An analytical expression of the axial stiffness of the isolator is deduced by derivative of the axial magnetic force with respect to the axial relative displacement of the inner ring. Furthermore, the parametric study of the axial magnetic force and stiffness are carried out. As a ring-shaped permanent-magnet passive vibration isolator case study, the isolator was constructed by four couples of the ring-shaped permanent magnets. The vibration isolation performance of the isolator was subsequently calculated and tested. The experimental results have shown a good agreement with the calculated ones. It demonstrates that the proposed isolator can realize low-frequency vibration isolation.