Investigation Of Scuffing Resistance And Influencing Factors Of Heavy Load Gear

Gear transmission is widely used in machinery due to its many advantages. With the continuous improvement of China’s industrial level, the requirements on the transmission gear performance have been promoting. The gears for heavy-load railway are required to be safer, more stable and less noise. With the increase of service load, gears failure inevitably occurs during service. Among them, the scuffing failure is one of the main failure forms. Different from other failure types such as pitting and spalling, gear scuffing is instantaneous. It will make gear operating conditions deteriorate rapidly, also lead to gear seizing, tooth breaking and other serious consequences. So such sudden failure is a great threat to the security of the train. The gear scuffing failure is influenced by load, lubrication state, processing quality and surface properties of materials. The research results show that the resistant capability of gear scuffing can be improved effectively by increasing the hardness of tooth surface, reducing the roughness and optimizing surface micro-topography. Fine particle shot peening and complex treatment can achieve them all, thus it is expected to improve the anti-scuffing capacity.In this study, according to national standard GB/T 13672-1992, the study scuffing experiment specimen which is equivalent to gear contact model is designed. Basing on the principle of improving the surface hardness and the surface roughness, traditional shot peening and fine particle shot peening technologies were used to process specimens into different groups, such as no treated specimens, single treated specimens and compound treated specimens. Then the detailed test of surface hardness and roughness was carried out to investigate the effects of different treatment on surface properties. Finally the resistant capability tests of gear scuffing were put into effect. The results show that the shot peening technology can significantly improve the anti-scuffing capacity of the gear material, and the combine of traditional shot peening and fine particle shot peening can improve the anti-scuffing properties of gear materials to be the largest. The traditional shot peening can increase specimen surface hardness and roughness, while the fine particle shot peening can increase the hardness further with the decrease of roughness. When the scuffing occurs, the friction coefficient and friction torque of the test increase sharply. The analysis of test results and EHL calculation show that the higher the surface hardness and the smaller the surface roughness, the better anti-scuffing performance of the test specimens. In addition, the surface texture effect of shot peening technology is of benefit to the anti-scuffing capacity of the test specimens.