Radial and Axial Integrated Auxiliary Bearing Device for Active Magnetic Bearing System

A type of radial and axial integrated auxiliary bearing (RAIAB) device with the function of simultaneously eliminate the radial and axial protective clearance after the magnetic levitated rotor dropped is conceived and presented in this paper. In the RAIAB, the two ends of the rotor and the inner races of the RAIABs mounted in each end are machined into cone-shape coordination. Besides, a series of ball are used between the outer races of the RAIABs and the pedestal. When the active magnetic bearing works, initial protective clearances exist between the two ends of the rotor and the inner races. After AMB system failure, the auxiliary bearing driven by an additional motor to produce axial movement which makes the cone surfaces of the inner races of auxiliary bearings gradually close with each end of the rotor until the protective clearance is eliminated. Therefore, the possibility of backward whirl and impacts can be reduced. Two different cone schemes of the rotor end shape are comparatively diskussed. Furthermore, the influences the value of taper of the cone on the protective clearance between the rotor and auxiliary bearing and the axial force produced by the radial force after the rotor drop. The preliminary prototype experimental rig was developed to demonstrate the feasibility of the RAIAB.