Modelling and analysis of thermal characteristics of high-speed train axle box bearings considering vehicle-environment coupling effects

Abstract

The axle box bearing is a critical component of high-speed trains. Investigating the thermal characteristics of axle box bearings under in-service conditions is essential for developing an effective temperature monitoring strategy. In this study, a non-linear thermal field model for axle box bearings, considering the vehicle-environment coupling effects, is established based on the bearing-vehicle coupled dynamics and finite element method. The validity of the proposed thermal model is demonstrated by comparing the temperature results with those obtained from a field test and calculated via the traditional method. Furthermore, the influence mechanism of vehicles and environment on bearing temperature was revealed, and the thermal characteristics of the axle box bearing under in-service conditions were analyzed. The results show that the vehicle affects the bearing temperature through the boundary load and wheelset speed, and these two parameters can have a significant impact on the power loss of the bearing and the convective heat transfer coefficient of the grease. The environment influences the bearing temperature by affecting the convective heat transfer coefficient on the surface of the axle box and wheelset. In addition, the track line parameters, such as curve radius and superelevation, may lead to the changes in bearing loads, consequently affecting the thermal behavior of the bearings. The maximum temperature of each bearing component increases with higher vehicle speed and higher ambient temperature. It is thus essential to consider the vehicle-environment coupling effects when analyzing the temperature characteristics of axle box bearings under operating conditions.