Research On Wear Theory And Experiment Of Spatial Gear Pair

Gear reducer is widely used in the aerospace industry.With the continuous development of China’s space technology,the working time of various spacecraft in orbit is correspondingly improved,which also puts forward higher requirements for the reliability of the space reducer.The wear of the reducer will affect its service performance and cause the failure of related moving parts.At the same time,the wear failure mechanism of the reducer in the space environment is totally different from that in the ground atmospheric environment.In view of this,this paper takes a planetary reducer gear pair as the research object,based on the existing space wear mechanism research and analysis model,analyzes the influencing factors of reducer wear in the space environment,carry out the thermal vacuum environment simulation test,explore the wear mechanism and performance degradation of the space reducer,provide basic theoretical support for improving the reliability and life of the mechanism which works in space environment.The main contents of this paper are as the follows:1)analyzed the failure mechanism of gear wear in space environment,based on Archard model and Johnson-wiliamson rough surface contact model,introduced the parameter K_S to characterize the wear performance of materials,the adhesive wear analysis of gear in the state of no lubrication and mixed lubrication is established,and the calculation formula of gear wear rate is obtained.2)Based on the Hertz contact theory,the contact problem in the process of gear meshing is analyzed by using the simplified model of gear meshing.The normal load and relative sliding speed of gear contact area are calculated.The instantaneous temperature rise of gear surface is analyzed by using block flash temperature theory and finite element method.It can provide guidance for the wear law under different vacuum cooling environment and working conditions.3)Taking the planetary gear of the primary transmission mechanism in a planetary reducer as the experimental object,the possible wear conditions of gear pair in extreme environment are analyzed,and the gear wear test-bed under extreme environment and conventional environment is built.The gear wear experiments under different temperatures,gear speed and load,and vacuum degree are carried out.4)According to the observation data of tooth surface under different working conditions and cycle times,the different wear forms and performance degradation of gear pair in normal temperature atmospheric environment and thermal vacuum environment are compared and analyzed.The effects of temperature,vacuum degree,speed and load on gear wear mechanism are discussed.The wear rate is calculated based on the wear depth of gear under different working conditions,The nonlinear fitting method of MATLAB is used to fit the change law of wear coefficient K_S.