The Modification Coefficient Research And Optimization Design For AT Gearbox

The gearbox is the core component of the bus,as an important part of the bus,The performance and service life of the gearbox are directly related to the performance and service life of the bus body.In the process of gear design,it not only seeked the light weight and economical efficiency,but also it's necessary to satisfy its good transmission quality while ensuring its service life,and these requirements basically depend on two aspects,one is gear parameter,the other is gear structure,material and heat treatment.Modification coefficient is one of the most important parameter of the gear parameter.In this disstertation,the optimal design value of the Modification coefficient bases on the gear transmission theory and verify the result by the KISSsoft.First,this dissertation introduced the background of the topic,the gearbox type of the passenger car and the development situation,show the transmission structure and parameter of the 2AT gearbox&the history of the gear and the vehicle's gear,analyzed the progress of the gear modification coefficient study at home and abroad,raised the problem that need to be solved and the solution in this dissertation,state the purpose and meaning of the gear Modification coefficient of 2AT gearbox.Second,by leading out the quotation for the modification coefficient and all kinds of the limitation condition according to the quality limitation requirement during the gear design,based on the EXCEL software,make the diagram to show the relationship between the modification coefficient and all kinds of the quality transmission requirement such as the gear undercut,overlap ratio requirement,tip width,the distance between the SAP and JFI and so on,and then pick up the range of the suitable modification coefficient that meet the transmission quality limitation requirement,provided the computational basis for the subsequent optimization design.Thirdly,introduces the common material of the vehicle gear,keep the gear base parameter the same,by studying the example of the modification coefficient distribution base on the same stress and same life requirement with the same gear material&HT with different core hardness,diferent material&HT with different core hardness,summarize the change trend.Forthly,set up the mixed object function that meet the transmission quality requirement,based on the Excel software,used the math method POWell and Genetic Algorithm separately calculated the best modification coefficient which meet the iterative accuracy obey their calculation characteristic,draw the drawing of Powell calculation method,compared the shortcut and advantage of the two method.Fifthly,use the modification coefficient to run the KISSsoft software,by verify the result of the modification coefficient before or after the optimization or the range of the modification coefficient which met the gear design quality restriction,we can know that the modification coefficient after POWell optimization not only meet all kinds of the transmission design quality restriction,but also meet the requirement of the safety factor of the gear root bending strength and gear contact strength,we also can know that much more suitable stress distribution by running TCA,achieved the purpose of the optimal design.The last,put forward the innovation of this dissertation and the prospect of the future.