Development And Performance Analysis Of Controlled Atmosphere Friction And Wear Testing Machine

Friction and wear testing machine is a device that simulates the friction and wear of mechanical parts under real conditions in the laboratory.In order to study the friction and wear characteristics of mechanical parts in a special atmosphere,a shaft-sleeve friction and wear testing machine which can control the environment of the experimental atmosphere is developed by taking the shaft-sleeve structure of the mechanism rotating pair as the research object,and the problems existing in the test machine are analyzed and improved.The main contents of this paper are as follows:According to the structural characteristics and experimental requirements of the experimental object,the overall design framework of the controllable atmosphere friction and wear testing machine is determined.The structure and design process of the test part,power system,loading system,experimental data measurement and acquisition system,pneumatic system of the test machine are expounded.The testing principle of the tester is introduced,and the measuring method of friction coefficient and wear volume is determined.In view of the cracking problem of the plexiglass seal cover of the tester during the experiment,the strength analysis and buckling analysis of the seal cover are performed based on the finite element analysis method respectively,and the reason for the breakage of the seal coveris determined to be instability failure.The influence factors of the stability of the sealing cover are analyzed by classical theory formula,linear buckling analysis and nonlinear buckling analysis.The results show that the thickness of the sealing cover designed in this paper is the main factor affecting the stability of the sealing cover,and the structure of the sealing cover is improved according to the analysis results.The empirical formula method,magnetic circuit division method and finite element method are used to analyze the loading force of the existing electromagnetic loading device,and the analysis result is compared with the measured value.The results show that the finite element simulation results are most close to the measured values.In addition,the proportional electromagnet structure is used to improve the loading device to solve the problem of unstable loading force during the experiment.The key parameters are simulated by the finite element method,and the optimal structural parameters of the loading device are obtained.Based on the analysis,it is found that the improved loading device has improved the existing problems.The friction and wear rules of the friction pairs composed of 45 steel and gray cast iron in air and nitrogen atmosphere are studied by using the developed test machine.And the influence of the material of the friction pairs on friction characteristics in air atmosphere is studied too.The experimental results show that the friction coefficient and wear rate in nitrogen atmosphere are higher than those in air atmosphere,and the frictional characteristics of the friction pairs composed of 45 steel and nylon in air atmosphere environment are the best.