| Reverse gear in transmission is one of important components of a vehicle, The research of the fatigue life has very important significance, well-designed reverse gear should have good static and dynamic mechanical performance,especially sufficient fatigue life. With CAE technology, do the research of the fatigue life and propose optimized solutions.First of all, according to the reverse gear product drawing, establish the geometric model with CATIA. After the geometric model is simplified and modified by Hypermech, establish the finite element model. Finite element statics analysis of reverse gear are carried on by MSC.Nastran, Compare The traditional statics calculation method of reverse gear, to evaluate the finite element results. According contact theory, Calculate and analysis surface contact stress, get distribution of surface contact stress of reverse gear in any time, and then compare the biggest contact stress result wich get by Hertz, prove accuracy of the finite element results and determine relationship between the stress changes with time. It can be seen that engaging course of reverse pulse in appearance, and lay the foundation for fatigue life analysis of reverse gear.Import the the finite element statics result into MSC.Fatigue,with the consideration of the factors affecting the fatigue life of reverse gear, S-N curve of reverse gear is established, and then calculate the fatigue life of reverse gear, and get distribution of fatigue life of reverse gear.According to the result of fatigue life analysis of reverse gear, propose optimized solutions to improve the fatigue life. From the viewpoint of increasing surface strength, propose nitriding and carbonization method, and prove the two method can improve the fatigue life of reverse gear. From the viewpoint of improving machine methods, propose precision forging method, and optimize processing technique. According the result of reverse gear product experiment, the fatigue life of reverse gear can be improved greatly. |
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