Analysis And Optimization Of Gear Process Design For Thin-Walled Large Helical Angle Gearbox

With development of the light truck market,the lower noise,higher comfort and lower-energy are becoming the basic requirements of the high-end light truck gearbox.Thin-walled large helix angle(>26°)high gear as the main components of the transmission,its accuracy directly affects the noise and stability of the gearbox.The structure of thin-walled gear parts with large helical angle is complex,the processing is difficult,the consistency of heat treatment deformation is poor,and the deformation mechanism is not fully clear;because of its large helical angle,the amount of pre-modification of shaving gear is larger than that of normal helical gear,and the tooth profile modification requires the left and right tooth surfaces to be modified separately,which makes the grinding of shaving cutter more difficult;in addition,the inner hole of thin-walled parts is easy to be deformed in welding and finishing of hot holes.As a result,the accuracy level of its teeth decreases.In order to improve the tooth processing accuracy,the heat treatment deformation law of thin-wall gear with large spiral angle is studied by finite element analysis in this work.The main research contents and results are as follows:(1)This paper investigates the field processing of thin-walled large helical gear parts,analyses the structure and process flow of the parts,summarizes the main defects in the actual processing,and analyses the mechanism of the main defects,and obtains the factors causing the poor accuracy of the Parts' teeth.(2)The finite element analysis software Ansys was used to simulate the heat treatment process of gears.The concepts of temperature field and stress field were applied to analyze the influence of heat treatment process on tooth deformation.Through the simulation analysis,it is found that the stress concentration occurs at theroot of the thin-walled large helical angle gear;during the pre-quenching period,the surface of the gear is tension stress,and the stress value increases with the change of time,and basically reaches the highest point at about 100 s.(3)In the process of heat treatment,the deformation rules of carburizing and quenching processes were studied,and the process parameters were calculated and optimized.The optimized parameters are obtained,including carburizing depth 0.83 mM,carburizing temperature 880 ?,strengthening time 140 min,quenching temperature800 ?,quenching oil temperature 110 ?,tempering time 2h,etc.Through the optimization of these parameters,the deformation of the parts is reduced,the deformation consistency is improved,and the variable momentum is controlled within0.006 mm.(4)The heat treatment technology and mechanical processing technology of the parts were optimized.The simulation results are verified by production and experiment.