Effect of shaft deflection on the dynamic behaviors of the ceramic bearing rotor system within wide temperature ranges

The shaft deflection has great impact on the dynamic characteristics of the ceramic bearing rotor system, which cannot be ignored within wide temperature ranges. This paper establishes a model considering the shaft deflection, and the impact of shaft deflection appears along with changes in bearing attitude. The interaction between the various components of the bearing is recalculated, and the dynamic behavior of the full ceramic bearing rotor system in wide temperature ranges is obtained based on the thermal deformation difference. The trends of dynamic behaviors with rotor mass, rotation speed and shaft length-diameter ratio are investigated, and comparisons between simulation and experimental results are conducted for verification. It is found that the shaft deflection makes impact by bringing in extra centrifugal force, and the effects are reflected in frequency components and trajectories. The simulation results with shaft deflection fit well with the experimental results, which proves that the dynamic model considering the shaft deflection better illustrates the dynamic behavior of the ceramic outer ring when the contact situations change with working temperature. The research carries out deep insight into the running of ceramic bearing rotor system, and provides guidance for the improvement of dynamic behaviors in wide temperature ranges.