| Face gear drive is a kind of transmission in which face gear meshes with cylindrical gear,which has advantages such as compact structure,good shunting effect,and insensitivity to installation errors,and it has already been widely used in batch installed applications in developed countries in Europe and America,however,the research on face gear manufacturing technology in China is still in the exploratory stage,and there is an urgent need for design and applied technology research in the fields of helicopters,ships,tanks,vehicles and machine tools.Currently,the existing machining methods of face gear,such as slotting,milling and skiving,have some problems in varying degrees,such as low machining efficiency,rapid tool wear,and difficult control of tooth surface profile,which seriously restricts the industrial application of face gear.In this paper,the near-net hot rolling forming technology is proposed to process straight face gear,based on the analysis of fatigue resistance and the prediction of fatigue life,the key technologies such as hot rolling precision forming method,metal streamline action law,bending fatigue life test and fatigue life prediction model construction are deeply studied,so as to form a feasible technical method of bending fatigue life prediction for hot rolling forming and provide a technical basis for the industrial application of straight face gear.The main research and results of this paper are as follows:(1)Aiming at the problem of optimization deviation of gear making process parameters caused by ignoring the interaction of evaluation indicators,a multi-objective process parameters optimization model based on the improved DEMATEL(Decision-making Trial and Evaluation Laboratory)and the improved TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution)is constructed.Based on the derivation of tooth surface equation of straight face gear and the digital tooth surface calculation,the straight face gear simulation model is constructed,and the finite element simulation of hot rolling forming process is completed,according to the simulation data,a multi-objective process parameters optimization model based on the improved DEMATEL and the improved TOPSIS is proposed,which solved the problem for process parameters optimization of hot rolling of straight face gear,on this basis,the hot rolling forming test of straight face gear is completed,which lays a necessary prerequisite for analysis of fatigue resistance characterization hot rolling and prediction of fatigue life for straight face gear.(2)Aiming at the lack of empirical evidence in the study of metal streamline distribution in hot rolling forming of straight face gear,the metal flow state and the law of different process parameters on the metal streamline of gear teeth and the metal streamline distribution state are found out,and the metal streamline defect suppression technology of straight face gear teeth oriented to anti-fatigue performance is formed.Based on the simulation of hot rolling forming process of straight face gear,through analysis of equivalent force,equivalent strain and metal flow velocity vector of hot rolling,the metal flow tendency of hot rolling forming process is determined,the influence law of process parameters on the metal streamline defect of hot rolling of straight face gear tooth surface is analyzed,and the evolution mechanism of metal streamline is grasped in forming process and different working conditions.The internal microstructure and the morphological characteristics of metal streamline of the teeth of hot rolling straight face gear and skiving straight face gear are analyzed by using metallographic microscope,and the distribution law of metal streamline in different parts of different processing methods is explored,which provides a basic basis for fatigue resistance of hot rolling forming of straight face gear.(3)Aiming at the problem of insufficient experimental verification data in the current research of bending fatigue life of straight face gear,the bending fatigue life test of straight face gear is carried out.Based on the simulation model of straight face gear,the bending stress simulation and bending fatigue life simulation of tooth root of face gear are carried out,combined with the simulation results,the test program is determined and the fatigue test bench is constructed,and the fatigue life test of straight face gear is completed.By using BP neural network-Bootstrap sample expansion method and Weibull distribution fitting,the reliable life calculation method oriented to sample expansion is constructed,and the small sample expansion of test results is realized,and the reliability life of skiving straight face gear is calculated,the simulation data of bending fatigue life is verified according to the reliability life data of skiving straight face gear,and the P-S-N curve of skiving straight face gear is drawn,which provides the test basis and theoretical support for the subsequent bending fatigue life test and bending fatigue life prediction of hot rolling straight face gear.(4)Aiming at the lack of data analysis in the research of bending fatigue life of hot rolling of straight face gear,a fatigue life prediction model based on GM(1,1,λ)-Artificial bee colony algorithm is constructed.Based on the bending fatigue life test and reliability life calculation of straight face gear,the reliability life calculation result of skiving forming straight face gear based on hot rolling is obtained,and the fatigue life prediction model based on GM(1,1,λ)-Artificial bee colony algorithm is proposed,based on the results of the reliable life of skiving forming straight face gear based on hot rolling,the fatigue life prediction of hot rolling forming of straight face gear is completed,and the credibility comparison with actual results and GM(1,1)prediction results is verified,and the validity of GM(1,1,λ)-Artificial bee colony algorithm is proved,and the lack of information analysis of fatigue life test data of hot rolling straight face gear is realized.The P-S-N curve of hot rolling forming of straight face gear is drawn and the comparison with the fatigue life results of skiving straight face gear based on gear blank is completed,and the results show that the bending fatigue life of hot rolling of straight face gear is improved by more than 12%,which proves the effectiveness and superiority of hot rolling forming technology of straight face gear. |
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