Process Study On Tube Free-bending With Joint Swing

In recent years,with the development of aerospace,automobile industry and other fields,more and more bending tube components are used as catheter or structural part.Traditional tube bending process are of poor flexibility,low production efficiency,and poor formability,that has been unable to fully meet the new manufacturing needs.Tube free-bending process with joint swing is a new tube bending process which originated from abroad.The process is of compact structure and high adaptable,and it realized tube three-dimensional free bending.However,due to the technical and commercial secrecy,the core technology of the process is not grasped independently in China.Therefore,this paper carries out some basic technical studies on the tube free-bending process with joint swing,the specific work is as follows:Firstly,the theoretical study of process principle was carried out.The theoretical geometric relationship of the process parameters was analyzed.According to the theory of metal elastic-plastic mechanics,the forces formulas were analyzed by using the improved metal constitutive model.Then,the design of bending device and bending action were studied.The design flow of the bending device of the process was described,and for a case,the bending device was designed detailedly,some design results of the bending devices for other size tubes was gave out.Used the finite element method,a bending device’s structure static mechanics was analyzed.Two work modes of the process were proposed and optimized.The compensation method of the bending angle error caused by the selected work mode was discussed.Furthermore,the process analysis and optimization were carried out.By the means of numerical simulation technique,the influence of the friction coefficient and tube advancing speed on the tube forming quality were studied,the inner cavity size parameter D1 of the bending model was optimized.Through multigroup numerical simulation tests,the relationship between bending radius and displacement of the spherical plain bearing outer ring was given.In the paper,some analytic calculation and numerical simulation are used to analyze the process principle,process design and process analysis and optimization of joint swing type free-bending process of tube.The study provides technical basis analysis for the industrialized development of process equipment,and has technical value for the engineering practice.