| With the continuous development of modern industry, the power that spiral bevel gears need to transfer is greater, the carrying capacity is much higher and the speed even faster, while the volume and weight of the spiral bevel gear becomes much smaller, which results in the integrated features such as the design, processing and manufacturing of spiral bevel gear. What is mentioned above has brought a great challenge. At present, the design and application of the aviation spiral bevel gear technology has become important factors which confine the development of aerospace equipments in China, such as overloading, greater power, lighter weight and longer lifetime. Taking the low bearing capacity and poor lubrication effect of a type of aero-engine high-speed spiral bevel gear in consideration, this paper adopts the methods of the finite element and finite volume with the detailed numerical analysis in the structure and lubrication.Firstly, aiming at a certain high-speed spiral bevel gear of the aero-engine whose transmission performance can not meet the requirements of the use of present situation, a method of increasing spiral bevel gear pair of original modulus and tooth width is put forward through the analyzing of the design of spiral bevel gear meshing theory, tooth contact analysis and its structure. The result indicates that the improved spiral bevel gear’s contact strength, bending strength and agglutination carrying capacity is improved with the use of the traditional calculation formula of the strength. Then, based on the finite element technology, an improved finite element model of spiral bevel gear was established and the meshing area of the contact stress and bending stress were analyzed in details. The results showed that the design had solved the problem of shortage in the original gear strength, the bevel gear contact fatigue strength increased by about 27.3%, tooth bending strength increased by about 40.2%, and tooth surface agglutination carrying capacity increased by about 28.7%.Secondly, the characteristics of spray oil lubrication on the bearing capacity of the high-speed spiral bevel gear were analyzed. For the reason that the meshing theory on the spiral bevel gear is quite complicated, numerical analysis directly on the lubrication is very difficult, this paper introduces a method of the equivalent spur gears. Combining the theories of tribology, heat transfer and fluid dynamics, the spray lubrication system was deeply researched such as the temperature field, pressure field and velocity field distribution and the change trend with the aid of computational fluid dynamics software. Then the major risk factors for spray oil lubrication (including lubricating oil viscosity, the gear speed and injection speed) on its bearing capacity were analyzed in details. Finally the analysis method of temperature, pressure, velocity on the gear lubrication system was summarized. The final result showed that the influence of viscosity and injection rate on the temperature field was larger, the influence of rotation speed and injection rate on the pressure field was larger, and the influence of three factors effect on the velocity field was more significant. Then this three factors of two coupling influence on lubrication were analyzed, more systematic research results to the influential factors of oil lubrication were summarized.In this thesis, the improved spiral bevel gear not only meets the using demand of the present stage, but also provides a technical support and help to improve the bearing capacity of the spiral bevel gear with the numerical simulation research using the finite element method and finite volume method. |
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