Research On Radial Extrusion Forming Technology And Tool Of Spur Cylindrical Gear

As a part of motion and power transmission,gears are widely used in various mechanical industries including automotive,aviation,shipping and other fields.Therefore,the constant pursuit of the superiority of gear forming quality is the main subject of research in the industry.There are two main gear processing methods,cutting and plastic forming at home and abroad.And plastic forming with its prominent advantages has become the dominant direction of the forming gear.By the method of gear cutting process,we can produce products with high precision,smooth surface and complex tooth profile shape.However,because of the shortcomings of low material utilization rate,low production efficiency and high cost,the method of gear cutting process has gradually faced to be eliminated.In addition,in the cutting process metal fibers will be cut off,which directly affects the gear teeth strength,wear resistance and service life.The plastic forming is a kind of gear forming method by the use of metal pressure.It is based on the principle of the same volume of metal in the plastic deformation.The method of plastic forming not only ensures the higher utilization rate,the productivity and the bearing capacity of the material but also the strength and life of gear teeth,which effectively improves the shortcomings of the cutting method and continues the advantages of cutting.And continuous improvement on the basis of the existing processing methods.On the basis of extensive reading literature and in-depth analysis,the paper puts forward a new process of gear radial extrusion forming,aiming at the shortage of existing gear plastic forming process,and designs the corresponding forming die.The process equipment utilizes punches to press radially so as to form a gear.Due to the change of the loading method,the forming load of the gear is effectively reduced.The gear tooth shape is fully filled,the strength of the tooth part is also improved and the gear fold phenomenon is effectively prevented in the axial extrusion process.The design step is to use the twodimensional software AutoCAD to design each part of the part map to draw a complete set of tooling map.Then building an three-dimensional model of the assembly by using the three-dimensional software UG/NX8.5.And elaborate the design characteristic of the parts in the assembly drawing as well as the movement way.Based on the FORGE finite element software simulation platform,the numerical simulation of thermo-mechanical coupling is carried out on the gear radial extrusion process.And the changing law and distribution of forming temperature,metal flow state,equivalent strain field and the stress field of the mold are also analyzed in the process of gear forging.Finally,by comparing the axial extrusion scheme with the radial extrusion scheme proposed in this project,acquire the relevant data from the simulation results.It is verified that the designed extrusion scheme not only reduces the forming load but also improves the die life.By simulating and analyzing the forming process of different modulus gears,the change law of radial squeeze pressure and clamping force is obtained,which provides technical basis for designing die and determining process parameters.