Research On Precision Forming Method And Gear Accuracy Of Cold Extrusion Gear For Trucks

As one of the transmission parts commonly used in machinery and automobile industry,straight tooth cylindrical gears play a very important role in industrial production.At present,the production and processing of straight tooth cylindrical gears are mostly still using the traditional hobbing,tooth insertion and other processes,the traditional machining methods have long processing time,tool wear fast,waste cutting and so on.Compared with the traditional cutting technology,the gear cold extrusion forming process has the advantages of high efficiency and low consumption,so more and more enterprises begin to use cold extrusion technology to process and produce gears,but the metal deformation is more intense during the cold extrusion process of gears,which makes the tooth precision of cold extrusion gears difficult to control.Taking the cold extrusion gear of truck as the research object,this paper determines the shaping scheme of tooth surface shaping and tooth top shunt according to the characteristics of cold extrusion tooth error distribution and numerical simulation analysis.By numerical simulation,the law of metal deformation and the influence of each process parameter on the tooth accuracy of the shaping parts were analyzed based on the tooth surface shaping and tooth top shunt scheme.In order to get close to the actual situation,an error model is established to simulate the influence of the unevenness of the end face of cold extruded gear on the accuracy of the cold finishing tooth orientation,and the law of the influence of the end face inclination on the tooth orientation deviation of the shaping gear was obtained.According to the fact that the quality difference of the end surface of cold extrusion gear will affect the effect of single stage shaping,a two-stage shaping process scheme of cold extrusion gear was proposed.The influence law of each process parameter on the shaping precision of the two-stage shaping scheme was obtained by numerical simulation analysis,and the parameters of two-stage shaping process are optimized by orthogonal experimental design The optimum combination of process parameters was obtained.According to the optimization results of numerical simulation and orthogonal experiment design,the two-stage shaping process test of cold extrusion gear of truck is carried out.The process test results show that the tooth accuracy of cold extrusion gears can be improved by using the two-stage shaping process based on tooth surface shaping and tooth top shunt scheme and selecting suitable process parameters.8Level.The test results verify the correctness of the numerical simulation.