Modeling And Simulation For Bending Stress Analysis Of Transmission Gears

Automobile transmission is the key to automotive driveline assembly, and the transmission gear is a key component of transmission. Gear's carrying capacity will affect the quality of the entire transmission system, thus affecting the overall performance of motor vehicles. Therefore, checking the intensity of transmission gear has great significance. Practice has shown that tooth bending fatigue fracture is one of the main forms of damage. In order to ensure the gear could work naturally in its life expectancy, its teeth root must have a capacity of anti-bend - bending fatigue strength. And solving bending stress is the mainly content of bending strength calculation.At present, the process of classical calculation method of bending stress which is used proverbially is very fussy, and demands to count lots middle coefficients and table data. It's very inconvenient to engineers who care the results of bending stress only. So it is necessary to realize standardization and create the special program for gear bending stress calculation. Analysis problem by finite element method is based on the physical model. Therefore, first is to establish accurate finite element model of gear before analyzing bending stress of transmission gear by finite element method. At present, the parametric modeling technology has made rapid development. In view of the trait of parametric modeling that use the relationship of geometric constraints, mathematical equations and models to figure the characteristic of the physical model, analyze the characteristic of two-dimensional and three-dimensional gear models to complete the process of their parameterized modeling. For the calculation of contact line which is the difficult of three-dimensional gear modeling, start to research from the contact lines corresponding to different mesh points of helical gear. Analyze the position of the contact lines of different gears when several of the different gear teeth meshing at the same time to improve efficiency and reduce the design cycle.With the development of computer technology, a variety of large and specialized finite element software become more sophisticated. However, the perplexing geometric model is created comparatively hard. Manual manipulation is not only inconvenient, time longer, but also has a certain degree of error. And this will affect the project design efficiency to a large extent. In view of the trait of parametric modeling, create the special program for gear bending stress finite element analysis which is based on a large commercial finite element modeling software, which is particularly important to improve efficiency and shorten the design time.This paper does a series of significant and valuable jobs according to aforesaid problems aiming at modeling and simulation for tooth root bending stress analysis of transmission gears. The main research contents and related conclusions of this paper are as follows:(1)Standardization for classical Bending Stress Analysis of involute column gears Consult GB3480-83, systematically analyze and summarize the classical calculation method of involute cylindrical gear tooth root bending stress. Induce and summarize the basic parameters of involute gear. Realize standardization of the load factor of gear contact, bending and bonding issue (coefficient of performance, dynamic loading factor, tooth width,tooth space load distributing factor).(2)Parameterized realization for the geometric characteristics of two-dimensional and three-dimensional solid model of involute gearFor the equivalent spur gear model which commonly used for engineering calculation of helical gear tooth root bending stress, established its involute tooth profile equation and the dedendum transition curve equation. Analyze the problems in the calculation of spur gear tooth root bending stress on the current equivalent spur gear model. On the basis of two-dimensional solid model of involute gear, according to the principle of creating helix base circle line, parameterize the geometric characteristics of three-dimensional (single-tooth and three teeth) solid model of involute gear. Began to research from the calculation of the contact line which corresponds to the different helical gear meshing point, analyze the position of contact lines on the different gear tooth when several different gear teeth meshing at the same time.(3)Use APDL which is the internal programming language of ANSYS to realize the two methods of Bending Stress AnalysisLearn APDL which the internal programming language of ANSYS deeply, and use APDL to realize Classical Method and Finite Element Method of gear bending stress Analysis. This will lets the bored and fussy manual modeling become an easy and automatic sequence work, and it brings the most convenient to engineers.Learn secondary exploitation of APDL to create the dialog box for input of parameters for two methods of tooth root bending stress analysis and achieve human-computer interaction. At the same time, for Classical Method, create the dialog box for output of tooth root stress and the document for storage of gear parameters. And it brings the most convenient to engineers for the extraction of stress and the preservation of gear parameters.