Study On Key Technology Of Multistage Cold Precision Forging Of The Shaft In Gearbox

Since 1990s, the sedan industry of our country developed in a high-speed. To produce the shaft in gear-box in traditional way cannot suit the requirement of market, so a new method with called multistage cold precision forging has been created. Comparing to the conventional shaft shaping, the new method has a lot of advantages such as more efficient, high-quality, material saving and energy saving. Base on the requirements of the project which has been undertaken by our research team, this paper will discuss the process of the multistage cold precision forging and die design.Base on the plastic forming theory and the cold extrusion process, the shaping characteristics and metal flow ruler of the cold ironing and cold upsetting has been analyzed. Then, the multistage process picture sheet of the hollow shaft and solid shaft has been worked out. According to the design size of the shaft, the forming force of every step has been calculated.The rigid-plastic finite element models of the hollow shaft and solid shaft have been established and the multistage cold precision process numerical simulation by adopting the FEM software DEFORM. After analyzing the results of simulation such the stress, strain, damage and the stroke-load curve, the process would be improved and the location of forging defects can be accurately predicted.Base on the structural characteristics of the press and feature of the multistage cold precision forging, the five-stage cold precision forging die of the shafts has been designed.A number of experimental data and qualified precision forgings were obtained from the process test of the input shaft and output shaft. The result proved that the theory research was correct and it will provide the technical support to the industrialization.