Finite Element Simulation And Virtual Realistic Simulation Of Composite Precision Forging Process For Spur Gear

The cutting process destroyed the continuity of the teeth of the metal fibers, was likely to cause the stress concentration sensitivity of fatigue, and introduce fatigue cracks that became the main reason for gear short lifetime. While precision forging could keep the metal streamlines on the gear tooth continuity and distribute along the tooth profile, and increase the strength and fatigue lifetime of gear teeth, had been developing rapidly. The spur gears had short comings such as heavy load, incomplete filling at the corner positions, short die life in its precision plastic forming process, and warm and cold forging process was the ideal process, it inherited the advantages of hot and cold forging and overcome their shortcomings.This thesis designed the warm and cold forming process for 18CrNiMo7-6 gear from Zhengzhou mechanical institute, the finite element model had been built and the optimal process parameters were obtained by finite element numerical simulation, At last we realized the virtual simulation of forging process on Open Inventor platform. The specific contents are as follows:(1)Based on the structural characteristics of gear, three kinds of warm forging programs were designed, then the corresponding models for finite element analysis in DEFORM-3D were established, according to the finite element analysis results of the velocity field, forming load and die wear, the double direction extrusion under the condition of free floating die was the best solution.(2)According to the features of the warm forging process to optimize the structure, additional diversion channels were added on the top and the bottom end face to reduce load of filling upper and lower corners and improve the forces condition of dies, that had been verified by numerical simulations. The parameters were optimized, according to the simulation results, the best warm forging temperature of workpice was 850℃, the preheat temperature of mold was 300℃, the friction coefficient was 0.1.(3)Cold finishing program and dies were designed. Since the deformation of cold forging process is small, elastic deformation can not be ignored, and the amount of elastic recovery of forgings calculated by Hooke’s law, the minimum amount of cold finishing was 0.2mm, elasto-plastic finite element method was adopted to simulate the effect of different amount of finishing deformation, Compare their forming load and die wear, the results showed that 0.2mm finishing allowance was the optimal solution.(4)Virtual reality software Open Inventor was adopted as a simulation platform, using C ++ achieveed conversion between dynamic plastic deformation model of DEFORM-3D and Open Inventor data format, then established three-dimensional scenes, realized the virtual simulation of forging process on Open Inventor platform.