Investigation Of Thermal Influence On Failure In High-Speed Sliding/Rolling Tribo-Contact

In aerospace, the environments are extremely harsh to the moving parts, such as high speed bearing and gear. The bearing failures, due to the contact thermal failure, seriously affect the reliability of the whole system. Take the example of three point contact ball bearing applied on the spindle of advanced aircraft engine, its dn value and work temperature are very high, often causing the contact thermal failures. As a result, it is highly needed to research the influence of contact thermal on the failure of high-speed sliding/rolling contact pair in bearing, to judge and prevent the thermal failure in advance, lengthening contact life and improving the reliability.This paper researches the contact thermal influence on the failure in high-speed sliding/rolling contact. High-speed sliding/rolling contact between two rollers is employed to simulate the contact in spindle bearing of aircraft engine. Thermal analysis of the contact between two rollers is carried out with theoretical calculation, finite element analysis (FEA) and experimental study.The contact theories and the thermal theories are employed, firstly getting the contact area and contact pressure, and then obtaining heat flux and heat transfer by thermal theories, which provide boundary conditions for FEA. Thermal properties of the high-speed sliding/rolling contact between two rollers are analyzed with FEA, obtaining the thermal distribution between two rollers. The influences of contact materials and operating parameters on the thermal distribution are studied. The results show that thermal distribution coefficient of the big roller is about 0.56-0.6. Among the factors, contact materials have few effects on thermal distribution, while the influence of the speed of rollers is obvious.With the calculated thermal distribution coefficient, frictional heat is proportional distributed to two rollers, calculating the temperatures on surface and subsurface. The effects of contact materials and operating parameters on the temperature are researched. As the results show, the maximum temperature locates on the center of the contact area. The small roller has higher temperatures on the surface and subsurface. The temperatures of both rollers increase with higher load and speed.In the experiment studies, the existing high speed sliding/rolling contact test rig is modified to test the surface temperature of two rollers at the same time, aiming at experimentally researching the temperature and its distributions between two rollers. The results of experiments are well identical with the FEA analysis results.