Research On Gear Transmission Wear And Health Evaluation Based On Similarity Analysis

With the development of society and the improvement of the level of science and technology,modern industrial fields have gradually realized mechanized operations,and various mechanical equipment has played a very important role in actual industrial engineering.Gearbox is an important part of the transmission system of various mechanical equipment.Its reliability is related to the operating state of the entire mechanical equipment.In order to meet the needs of industrial production,the gearbox has to work in a complex and harsh environment.The gears in the gearbox are prone to wear and fail under long-term overload conditions.When faced with gearbox failures of large equipment such as wind turbines and heavy machinery,not only the reliability and safety of the overall equipment must be considered,but also the actual working conditions and other factors need to be understood,which consumes a lot of manpower and material resources in solving the problem.Therefore,based on the similarity analysis,this paper proposes a similarity model theory for large equipment gear box,designs the similarity model test using the theory,and studies the wear state of gear from all aspects by means of ferrography analysis,electron microscopy analysis and other techniques.In this paper,the basic principle of similarity theory is expounded.Based on the structural mechanics and similarity theory,the similarity criterion of each parameter of model and prototype is deduced,and the similarity ratio is calculated.The simulation analysis is carried out by finite element software,which verifies the feasibility of similarity model based on similarity in the dynamics and structural mechanics.The gear wear test was designed according to the similar parameters.Before the experiment,Hypermesh and ANSYS co-simulation were carried out on the experimental gear to observe the stress distribution in different positions of the gear teeth.The force and wear of the gear in the experiment process were judged according to the analysis results.The gear wear experiment totaled 170 hours.During the experiment,continuous sampling was carried out without stopping,and the oil samples were processed and analyzed.The particle counter was used to count the size and number of wear particles in the oil at different time periods and under different states,and the curve of the oil wear particle concentration changing with time in the gear wear process was obtained.The spectrum slices of different time periods and the gear tooth slices after failure were observed and analyzed by means of single-link analysis ferro spectrometer,scanning electron microscope and other instruments.By identifying the wear types of abrasive particles and the wear types of the surface morphology of the gear tooth slices,the health conditions and wear states of the gear under different operating times were judged.The results show that stress concentration occurs at the root of the tooth,and the gear tooth is broken from the root;In the process of gear wear,there are more abrasive particles generated during the running-in period and the severe wear period.Large abrasive particles with a particle size of more than 50 μm will aggravate the wear;The severe wear period is mainly fatigue wear and severe sliding wear,and bearings and other parts will also produce severe wear;According to the information of abrasive particles and tooth surface,the wear state of the gear can be judged and analyzed.Based on the similarity analysis for the gear wear similar model experiment,combining the similarity theory and gear wear experiment,the wind power gear box and other large equipment similar to small gear wear test bench,simulate the actual working condition,analysis and research of gear wear state in practical engineering,save resources and research costs,enriches the research methods of large mechanical structure based on the similarity theory,for large equipment gear wear and tear of the state of the research provides a new way of thinking,has important theoretical significance and reference value.