Investigation on the misalignment of full ceramic ball bearing rotor system caused by varying gap in wide temperature ranges

The temperature-varying gap between the full ceramic ball bearings and the steel pedestal in wide temperature ranges leads to misalignment of the bearing rotor system, and there is a significant impact on the vibration of the rotor system. In this paper, the dynamic model considering the temperature-varying gap and time-varying contact between the full ceramic ball bearing and the steel pedestal in wide temperature ranges is proposed. The rigid body elements and the inner rings are coupled in the model, and the influence of the temperature-varying gap is analyzed. Results show that the increased gap at high temperatures brings about the looseness of the full ceramic ball bearing, the misalignment occurs between the axes of the two full ceramic ball bearings due to the looseness. The interaction between the full ceramic ball bearing and the steel pedestal becomes more significant, which causes the vibration of the rotor system to rise. Appropriately increase the interference between the full ceramic ball bearing and the steel pedestal helps reduce the gap at high temperature, thus avoiding the excessive vibration caused by misalignment and improving the rotation accuracy of the rotor system. The research results provide a reference basis for the use of full ceramic ball bearings in wide temperature ranges.