Development and stability analysis of a high‐speed train bearing system under variable speed conditions

During a high‐speed train operation, the train speed changes frequently, resulting in motion change as a function of time. A dynamic model of a double‐row tapered roller bearing system of a high‐speed train under variable speed conditions is developed. The model takes into consideration the structural characteristics of one outer ring and two inner rings of the train bearing. The angle iteration method is used to determine the rotation angle of the roller within any time period, solving the difficult problem of determining the location of the roller. The outer ring and inner ring faults are captured by the model, and the model response is obtained under variable speed conditions. Experiments are carried out under two fault conditions to validate the model results. The simulation results are found to be in good agreement with the results of the formula, and the errors between the simulation results and the experimental results when the bearing has outer and inner ring faults are found to be, respectively, 5.97% and 2.59%, which demonstrates the effectiveness of the model. The influence of outer ring and inner ring faults on system stability is analyzed quantitatively using the Lempel–Ziv complexity. The results show that for low train acceleration, the inner ring fault has a more significant effect on the system stability, while for high acceleration, the outer ring fault has a more significant effect. However, when the train acceleration changes, the outer ring has a greater influence. In practice, train acceleration is usually small and does not frequently change in one operation cycle. Therefore, the inner ring fault of the bearing deserves more attention.