Optimization Of Forging Process Of CVJ Spherical Housings Based On Numerical Simulation

Spherical housing is a key forging part in constant velocity joint(CVJ)which is an important part of automobile transmission system.At present,the domestic automobile industry is developing rapidly and needs a large number of precision forging parts.CVJ spherical housing is the research object in this paper,which has studied the difference of three schemes in forging flow lines,forging load and die wear with FEM software Deform.Meanwhile,this study has optimized forging process parameters and forging die with the combination of Kriging surrogate model and Particle swarm optimization(PSO),which has important guiding significance to actual production.The main study contents and conclusions are as follows:In the first place,this paper has studied the difference of three schemes in forging flow lines,forging load and die wear with finite element analysis software.According to the numerical simulation results,forward extrusion-upsetting-backward extrusion is the best scheme.The simulation results also show that the influence of billet diameter on forming load and die wear is limited,but the effect on Forging flow lines is very large.Through the comparative analysis,it is determined that better forging flow lines can be obtained by using the billet with a diameter of 70 mm.The results of the actual industrial trial show that forward extrusion,upsetting,backward extrusion scheme is better than upsetting,backward extrusion scheme in forging flow lines.In the second place,forging process parameters have been studied with FEM and Kriging-PSO.The response relation between Billet temperature,punch velocity,die temperature and forging load,die wear has been abtained by building Kriging surrogate model.According to the optimized process parameters,forging load and die wear can be reduced by 10.0% and 29.6%.Thirdly,the characteristic of punches with different geometric shapes has been studied,and tapered punch with flat top has been choosed in back extrusion formingprocess.And then,The key factors affecting forging load and die wear in punch size have been found with fractional factorial design.After that,the best punch size which has been obtained with Kriging-PSO optimization algorithm has reduced forging load and die wear by 7.86% and 7.16%.Finally,in order to solve the problem of unevenness of the end face of the cold sizing cup,the size of preformed workpiece in cold sizing has been studied with the optimum design.With the objective of the smaller height difference of cup wall,the size of preformed workpiece has been quantitatively optimized.Then,the optimized dimensions parameters have been obtained with Kriging-PSO optimization algorithm.The results of the actual industrial trial show that the problem of unevenness of the end face of the cold sizing cup can be solved effectively with this method.The height difference of cup wall has been reduced form 12 mm to 3mm.That is,the amount of cutting metal in subsequent machining has been reduced,and the material usage rate has been improved effectively.