Research On Key Technology Of Multi-stage Cold Precision Forging Of Solid Step-shaft In Automatic Equipments

According to the specification of the key research project of Hubei Province Development of Multistage Cold Precision Forging Process and Equipment for the Gearbox Shaft charged with our research team,the key technology for sequential production of solid step-shafts in gearbox with 16MN five-stage hydraulic cold precision forging automatic production line were discussed. Besides, the design principles and demands of forging process and equipments were also introduced.On the foundation of finite element simulation and experiment data,the multistage cold precision forging processes of solid step-shafts were researched, with the laws of the metal flowing during ironing and upsetting analyzed separately. According to similarities and differences between ironing and plus extrusion, the forming mechanism explaining why the step-shaft has a gibbous end in plus extrusion but a sunken end in ironing was carried out. Another explication about the slight bulging problem of the blank during deforming was also put forward. Those above were beneficial for optimizing the multistage cold precision forging processes.Based upon the research on forming processes, principles and methods of solid step-shafts multistage processes and dies designing, which include cold ironing and cold upsetting , were summarized. Structural characteristics and designing key points of the dies, which are composed of five die units and works with a five-stage step-by-step transformer, were also stated, while a designation of the five-stage cold precision processes and their dies of the mid-shaft parts was also presented.The system framework of 16MN five-stage hydraulic cold precision forging press was described,guided by requirements of the multistage processes and dies. After the designation of the five-stage step-by-step transformer was completed , motion models of all the components of the five-stage automatic production line were established. The coordination of all the components,which were expected to run without interference was achieved by virtual prototype technology and sequence designing. The procedure simulation and design parameters optimization of the automatic production line were implemented by using the virtual prototype software MSC ADAMS.