Strength Analysis And Optimization Design Of EMU Gear Transmission Device

The gear transmission device is an important equipment of high-speed train power transmissions, it is not only one of the ten major supporting techniques of high speed EMU, but also one of the most important transmission links of EMU transmission systems. The requirements of precision and reliability for the gear transmission device is quite high, it is also very difficult to design and manufacture, it has a very big relations to driving safety. In this paper, we choose a type of EMU gear transmission device which was designed by a factory as the research object, mainly focuses on the three important parts of the driving device: the gear box suspension device—C-bracket, gear system and gear box. Using the finite element method and topology optimization method to make the structural analysis, the dynamic characteristic analysis and design optimization for the transmission device. Trying to reduce its design flaws, stress damage phenomena and possibility of resonance damage occurring. Thesis is as follows:Firstly, background and significance of the topic is presented. Looking at the present research results of the gear transmission device, we put forward the research methods and content, then build the geometric models of critical components of the gear transmission device and simplify them.Next, we choose the C-bracket for the first study. Using ANSYS Workbench software to make finite element static analysis for C-bracket, we can get stress distributions under different working conditions. Strength evaluation results show that the C-bracket can meet static strength requirements. Then we make fatigue strength evaluation for C-bracket by the Goodman-Smith fatigue limit diagrams, results show that the selected fatigue check points are all in the envelope of Goodman fatigue limit diagram, C-bracket meet fatigue requirements. Finally, we make the light quantitative design for C-bracket. Choosing minimize volume as the objective function, We constraint the strength and stiffness which must satisfy the material properties of C-bracket, then make topology optimization design for C-bracket and verify the optimized C-bracket, results show that the stiffness of optimized C-bracket have improved tremendously, and the quality reduce 8.6% than the original structure.Subsequently, we make the study of static and dynamic characteristics for gear system, including analysis of bending strength of gear tooth, gear contact strength analysis and transient dynamics analysis.Finally, we study the gearbox. Making finite element static analysis first, results show that the strength of the box meet the requirements of TB/T 3134-2013. Then make the modal analysis, the top ten natural frequencies of gear box have avoid of the predictable internal meshing frequency, so the box cannot easily resonated. In order to get better gear box structure, we considered from the perspective of static and dynamic design, and make multi-objective topology optimization design for gear box. The objective function is minimized the former third frequencies and maximized flexibility to enhanced structural rigidity. Optimize design is based on the topological density picture. Analysis results showed that the optimized gear box comprehensiveness can be improved, and achieve lightweight design.