A novel model for investigating the thermal equilibrium characteristics of a high-speed train gearbox

Accurate analysis of the thermal equilibrium characteristics of high-speed train gearboxes can aid in preventing high-temperature malfunctions and ensuring the safe and efficient operation of trains. Owing to the complex heat transfer routes and interdependencies within the gearbox, establishing a precise thermal analysis model is essential. In this work, a finite element thermal network model is proposed to predict the temperature distribution of a gearbox. The moving particle semi-implicit method is used to determine the flow state of the lubricant and the convective heat transfer coefficients on the surfaces of the components. Power loss, which contributes to heat generation, is categorized into gear meshing, oil churning, and bearing friction. A thermal network model and finite element model for thermal analysis are subsequently developed based on heat transfer relationship, and data exchange between the two models is achieved through the BoundaryToFEM unit. The effects of the gear rotation speed, convective heat transfer coefficient between the components and lubricant, and heat transfer coefficient between the outer surface of the gearbox and ambient air on the thermal equilibrium are analyzed. The results indicate that when the input gear speed increases from 2104 rpm to 5259 rpm, the total power loss increases by 2159 W, and the heat balance temperature increases by approximately 53 °C. When the convective heat transfer coefficient between the components and lubricant varies from a 50 % reduction to a 50 % magnification, the thermal equilibrium temperature only changes by 1–2 °C. However, when t between the outer surface of the gearbox and ambient air undergoes the same variation process, the thermal equilibrium temperature decreases by approximately 82 °C. The full-scale gearbox running-in experiment shows that the predicted temperatures of the bearing cups remained within a deviation range of 2–5 % from the experimental values, and the maximum error of the lubricant temperature was 3.18 °C, which further verifies the accuracy and reliability of the proposed model.