Study On The Service Lifetime Of The Gear Rolling Tool

The high efficiency and precise gear rolling forming technology is a new type of gear manufacturing method.The feature of this technology is that it can ensure the metal material flow line will not be cut off during the manufacturing process.Compared with the traditional method,it has the advantages of high efficiency,high material utilization and good fatigue lifetime of gear products,so it is being more and more valued in the industry field.As a kind of rolling mould,gear rolling tool is one of the key components of rolling forming equipment,and it directly contacts with the material to realize the rolling process.Its service lifetime and durability have a direct impact on the efficiency and economy of production.The production practice shows that the rolling tool is under high level cyclic loading in the process of large module steel gear forming.If the design parameters are not properly controlled,the fatigue fracture failure phenomenon of the gear rolling tool is easily occurred,which seriously affects the production.However,the research on this aspect is very limited in the worldwide.In this paper,the service lifetime of gear rolling tool was studied based on the theory of fatigue and fracture mechanics,which provided valuable reference for optimizing the process parameters and improving the service lifetime of the gear rolling tool.This paper will study on the following aspects:(1)The main process and mechanism of fatigue failure,the quantitative calculation method of fatigue lifetime and the crack propagation analysis were described.The research method for fatigue fracture failure analysis and service lifetime evaluation of gear rolling tool was constructed based on the theory of fatigue and fracture mechanics.(2)The service lifetime evaluation parameters of cold working die steel DC53 were determined based on the ultimate tensile strength,fracture toughness and crack propagation rate.(3)The axial rolling process of gear was simulated based on the nonlinear finite element method,and the die stress of gear rolling tool was analyzed to develop the stress evolution law of gear rolling tool in the service process.(4)Study on the service lifetime of gear rolling tool based on the finite element method,the fatigue lifetime under the service condition was calculated according to the material life assessment parameter,and the crack propagation lifetime was evaluated by elastic fracture mechanics.(5)The influence of the axial feed speed and rolling wheel speed on stress state and service lifetime of the rolling tool were studied,which provided a reference for optimizing the rolling process parameters and improving the service lifetime of the rolling tool.In this paper,the fatigue fracture failure of gear rolling tool was comprehensively studied based on the fatigue theory and fracture mechanics by the theoretical analysis and numerical simulation methods.The research results provide technical support for service lifetime evaluation and materials selection of gear rolling tool,and the practical application of the high efficiency and precise gear rolling forming technology.