Finite Element Analysis And Optimization Design Of The Press-fitting Unit Of The Automotive Radiator-core Assembly Machine

With the development of automotive industry, the radiator-core assembly machine in the modern automobile parts manufacturing has been widely applied. Most national traditional assembly machines with semi-automatic or manual assemblies were difficult to guarantee the assembly quality and precious of radiator-cores. Therefore, a brandnew automatic automotive radiator-core assembly machine with independent intellectual property was developed. It is necessary to simulate the machine and the parts’ performance and optimization design the weak links in computer before prototype development.Setting the developed press-fitting unit of automotive radiator-core assembly machine as the research objective, the structural is analyzed and optimization designed by means of finite element method and multi-objective design method in this thesis. It mainly includes the following contents:1. The structure composition, working principle and primary technical parameter of the press-fitting unit of the developed radiator-core assembly machine are briefly introducted. In addition, the press-fitting unit is divided into three parts, including tamping and leveling module, press-fitting and flaring module and fuselage module. The scheme of finite element analysis is subsequently put forward.2. The parametric models of three parts are built, after that the force analyses are carried out and then finite element models of three parts are rationally established. Both static and modal analysis on the three parts are performed based on ANSYS Workbench Environment(AWE), which is a software of finite element analysis. The stress distribution, static deformation, inherent frequency and dynamic mode shape of the structures are obtained and the result shows that the designed structure of the press-fitting unit is reasonable. On the premise of the assembly accuracy requirements, the deformation of key components would affect the accuracy of assembly is analyzed. The result shows that the deformation of the screed of the tamping and leveling module and the worktable of the fuselage along Z-axis meet the flatness requirement 5.09×10-5m, which affect the roughness of work-piece and they are respectively 1.09×10-5m and 1.09×10-6m. Besides, the deformation of both sides of mainboard-die of the press-fitting and flaring module along Z-axis and the deformation of sideboard-die along X-axis are respectively 2.24×10-5m, 1.09×10-5m and 2.6×10-5m, which affect the press-fitting of mainboards and the location of the ports and their sum value is lower than the requirement of the position precision 5.09×10-5m.3. In order to have the press-fitting unit of the assembly machine optimized based on multi-objective genetic algorithm and response surface methodology, the main structural and position dimensions are selected as the design variables, while the maximum equivalent stress of the structure and natural frequency of first-order are set as the constraints. Also, since the deformation of key components would affect the accuracy of assembling, reducing the degree of deformation and the quality of the structure become the objective. By optimization, the weight of the tamping and leveling module, press-fitting and flaring module and fuselage module are respectively dropping 8.77%, 8.52% and 4.31% compared with before, while the dynamic and static performance of the optimized structure also improve.