In the magnetic levitation bearing system, a set of protective bearings is needed as temporary support for the rotor after the magnetic levitation bearing fails, to protect the equipment from damage. Traditional protective bearings often cannot support the high-speed rotor rotation and are difficult to withstand the vibration and impact caused by the rotor falling. In response to the shortcomings of traditional protective bearings, this article proposes to use double-layer ball bearings as protective bearings and conducts a series of related studies Before the double-layer ball bearing was used as a protective bearing, its mechanical characteristics were analyzed first. Based on the principle of quasi Statics, the mechanical model of the double-layer ball bearing was established by considering the radial load, axial load, centrifugal force of the ball itself and the combined load of gyroscopic torque. Based on the MATLAB platform, the calculation program for the mechanical characteristics analysis of single and double-layer ball bearings was compiled, And studied the influence of relevant parameters on the mechanical characteristics of bearings, built a rotor bearing system test platform, and verified the simulation results through experiments. The research results showed that the pitch diameter ratio of the inner and outer layer bearings directly affects the speed distribution of the double-layer ball bearings; Under the same working state, compared to single-layer ball bearings, double-layer ball bearings have smaller radial and axial support stiffness; The external load and working speed affect the changes in the ball contact angle of single and double layer angular contact ball bearings. The centrifugal force of the ball causes the contact angle between the ball and the corresponding inner and outer raceways to no longer be equal; External load, working speed, ball material, groove curvature radius, and initial contact angle of the ball have certain effects on the axial and radial deformation of single and double layer angular contact ball bearings; The radial clearance, working speed, and radial load have a certain impact on the radial deformation of single and double layer deep groove ball bearings
