The Analysis For The Main Factor Affecting The Wear Of Space Gear

With the development of space technology, the lives of mechanical component become one of the key problems in space technology. Gear mechanism is an important transmission mechanism and has a wide range of applications in the spacecraft. The research of production condition and suppression method of the wear of space gear to improve the reliability and the life of space gear mechanism has an important theoretical and practical significance. Gear contact stress is the main factors of the gear wear. In this paper, the coupled thermo-mechanical contact analysis of space gear in vacuum environment was carried out, and the thermal vacuum test was carried out to verify the result of the coupled thermo-mechanical contact analysis.The mathematical model of gear contact stress changing along the meshing line was established based on Hertz contact theory. A numerical method was developed in MATLAB?. The distribution law of gear contact stress along the meshing line was obtained in the process of gear meshing, and lays the foundation for the analysis of the temperature in gear contact area. The effects of torque, pressure angle and tooth width on the gear contact stress were analyzed. The gear contact stress obtained by numerical calculation and finite element contact analysis was compared to verify the correctness of the finite element analysis model.Mathematical model of flash temperature in gear contact area changing along the meshing line was established based on Block flash temperature theory. The distribution law of the flash temperature in gear contact area changing along the meshing line in the process of gear meshing, which is the boundary conditions of the coupled thermo-mechanical contact analysis was obtained. The effects of torque, speed, sliding friction coefficient and pressure angle on the flash temperature of gear contact area were analyzed. The space gear contact stress obtained by coupled thermo-mechanical contact analysis and without the boundary conditions of temperature was compared to analyze the effect of temperature in gear contact area on the contact stress.The space gear mechanism thermal vacuum test was carried out, and the weight of each gear was measured to study the gear wear. The wear form of space gear mechanism in the vacuum environment was observed, and the degree of wear at the addendum, near the pitch and between the addendum and the tooth pitch, were analyzed by SEM. The result of the coupled thermo-mechanical contact analysis was verified by corresponding relation between the degree of wear and gear contact stress.