Research On The New Hot Die Forging Technology For Local Load Of Bull Gear

As one of the indispensable basic parts of mechanical transmission, gears are widely used in various fields of machine manufacture. With the progress of technology, the metal plastic forming method has attracted more and more attention. Among them, the forging process has been gradually used in the production of all kinds of gear on a large scale. Compared with the traditional gear cutting method, microstructure and properties of gear can be effectively improved, the material utilization and productivity is also greatly increased. But for bull gears, the application of the forging technology is limited due to the large forming load. Considering the large size gear as the research object, a new gear forming process is designed and developed in this paper, and the process are analyzed and discussed.On the basis of the traditional gear upsetting extrusion process which is first introduced, shunting forging technology is brought in, then using the way of local loading, ultimately the big gear local loading hot die forging process is determined.The forging process is simulated by the large commercial software DEFORM-3D, through adjusting the mould structure and gear blank a set of billet size parameters that meet the forming conditions is found, then the plastic deformation characteristics during the forming process are analyzed, including the metal flow law, distribution of equivalent strain field, displacement field distribution and the load-stroke curve. In addition, taking the gear filling conditions and forming load into consideration, the influence of process parameters, including the friction coefficient, characteristic parameters, forming temperature, etc, on the forming results is discussed. Finally, experiment is carried out to verify the process, and the experimental results are in agreement with the numerical simulation results, which provide technical support for the practical application of the process.For the forming process which studied in this paper, the forming process of different modulus gear is numerically simulated by using the orthogonal experimental design. Through analyzing the test results, the primary and secondary factors of blank size that affecting the forming of different modulus gears are obtained, that is the billet height is the main influence factors of forming, so the greater the modulus, the easier it is forming.