Nonlinear dynamic analysis of ceramic bearing rotor system considering temperature variation fit clearance

Under high-speed and high-precision operation, the ceramic bearing rotor system will generate high temperature rise. Ceramic bearings and steel bearing pedestal will produce different thermal deformation due to material differences, which will lead to the non-uniform change of fit clearance. Based on the bearing heat generation and deformation mechanism, the clearance fit model of ceramic bearing rotor system is established, the contact relationship between bearing outer ring and pedestal is analyzed, and the nonlinear dynamic model of ceramic bearing rotor system considering temperature variation clearance fit is established. The nonlinear vibration characteristics of bearing rotor system under the influence of temperature variation fit clearance are investigated, and the system stability is analyzed by using phase plane diagram and bifurcation diagram. Finally, the model is verified with vibration experiments. The results show that the thermal deformation difference between the outer ring and the pedestal increases with the increase in internal temperature. The existence of temperature-varying clearance makes the amplitude of the rotor system fluctuate locally, and the vibration changes from periodic vibration to quasi-periodic motion and lengthens the chaotic period. The stability of the rotor system can be better maintained by properly reducing the bearing fit clearance at high speed. The research results lay a theoretical foundation for the further optimization design of ceramic bearing rotor system.