Research On Axial Split Cold Extrusion Process Of Automobile Differential Gears

The differential is one of the common transmission parts in automobile.It plays a role in adjusting the wheel speed difference in the running of the car.The production quality of the differential gear closely affects the performance and driving safety of the differential.With the rapid growth of automobile production,the demand for differential gears has skyrocketed,and the quality standards have also significantly improved.The traditional cutting methods inevitably have the problems of low processing efficiency and low material utilization.Cold extrusion technology is a kind of precision plastic forming technology that produces fast,energy-saving,environmental-friendly,green and high quality,guarantees the quality of the products in mass production,saves the production cost of the enterprise,so the high-tech cold extrusion forming technology is gradually replacing traditional cutting process.However,due to the characteristics of the differential gear shape structure,the metal flow law in the cold extrusion forming process is complex,resulting in easy forming defects of the extrusion;During the extrusion process,the elastic deformation of the die and the springback of the extrusion after the forming process both affect the forming accuracy of the differential gear and reduce the meshing performance of the gear.Therefore,these severely restrict the application of cold extrusion technology in the manufacture of differential gears.Therefore,improving the forming quality and precision of the automotive differential gear is of great theoretical significance and high practical application value to the development of automobile parts manufacturing industry.This article takes the automotive differential gear as the research object.Based on the problem of cold extrusion forming defect of automobile differential gear,the 3D geometric model is established by using Gear Trax and SolidWorks software,the numerical simulation extrusion process was reproduced by using the rigid-plastic finite element software,the flow of metals was observed,the cause of tooth profile defects were analyzed,and axial split cold extrusion forming process for differential gears was proposed,numerical simulation results show that the problem of "missing metal" can be effectively avoided by adopting this process on the addendum,and the feasibility of this process is demonstrated.In order to further optimize the process,the influences of the spherical diameter of the punch,the entrance half angle of the die,the thickness of the split step on the gear forming were studied,the optimal process parameters was determined by analyed.Cold extrusion forming of differential gear based on the elastic-plastic finite element simulation of optimal process parameters,the elastic deformation rules and springback data of the die and extrusion parts are obtained.The data of the collected nodes are fitted by the MATLAB software to get the contour map of the tooth profile,and the springback of the tooth surface can be displayed intuitively.The method of back compensation modification of die cavity is adopted,and the back compensation correction is carried out through tooth orientation modification and tooth shape modification.In order to ensure the accurate modification quantity and reduce the number of technological tests,the precision quality of the formed gear surface is tested by using the gear measurement center and the gear meshing machine.The optimum shape modification of the tooth cavity is obtained through several iterative tests,which ensures the forming accuracy of the tooth surface.The meshing performance of differential gear is improved.