Characteristic analysis of mechanical thermal coupling model for bearing rotor system of high-speed train

Based on Newton’s second law and the thermal network method, a mechanical thermal coupling model of the bearing rotor system of high-speed trains is established to study the interaction between the bearing vibration and temperature. The influence of lubrication on the vibration and temperature characteristics of the system is considered in the model, and the real-time relationship between them is built up by using the transient temperature field model. After considering the lubrication, the bearing outer ring vibration acceleration and node temperature considering grease are lower, which shows the necessity of adding the lubrication model. The corresponding experiments for characteristics of vibration and temperature of the model are respectively conducted. In the envelope spectrum obtained from the simulation signal and the experimental signal, the frequency values corresponding to the peaks are close to the theoretical calculation results, and the error is very small. In the three stages of the temperature characteristic experiment, the node temperature change of the simulation model is consistent with the experiment. The good agreement between simulation and experiments proves the effectiveness of the model. By studying the influence of the bearing angular and fault size on the system node temperature, as well as the change law of bearing lubrication characteristics and temperature, it is found that the worse the working condition is, the higher the temperature is. When the ambient temperature is low, the viscosity of grease increases, and the oil film becomes thicker, which increases the sliding probability of the rolling element, thus affecting the normal operation of the bearing, which explains the phenomenon of frequent bearing faults of high-speed trains in the low-temperature area of Northeast China. Further analysis shows that faults often occur in the early stage of train operation in the low-temperature environment.