Research On Gear Tooth Modification And Engaging Load Of Increasing Gearbox Of Megawatt Wind Turbine

Gears are commonly used in industry, especially in the wind power generation equipment in the recent years, which requires better performance. Modification has a great significance to improve the loading capacity of gears. Output gears of increasing gearbox of Megawatt Wind Accelerator were studied in this paper. Based on principles of involutes gears and vibration theory, the analysis of mesh load based on theoretical, completed helix angle modification and tooth profile modification was made. And using finite element software to simulate gear dynamic contact, the analysis of the gear mesh load distribution and the compare of pressure distribution and contact stress before and after modification were made.Firstly, the formulas of continuous profile curves are acquired from the formulas of the cutter profile curves, the precise models of pinion and large gear were built and the assembly was completed in NX. And then, the analysis model was imported into finite elements software and meshed.Secondly, combining the deformation compatibility condition and the force equilibrium of the engaging helical gear, a linear equation with node force and engagement deformation was established. Application of finite element software to simulate the meshing process, the contact stress contours of meshing were generated, and the stiffness coefficient and friction coefficient was selected for the analysis results.Thirdly, analysis and comparison of the three tooth modification method, helix angle modification is used as tooth modification program. Gear with shaft was analyzed by finite element software, determining the amount of helix angle modification. Based on the theory of tooth profile, the maximum modification of tooth profile curve length, height and modification curve is determined.Finally, the pressure and contact stress of a meshing circle was analyzed in the finite element software. The analysis shows that the modification can improve the tooth contact stress distribution, eliminate stress concentration and improve the strength of gear's contact, reduce the tooth interference and impact. It proves that the modification method adopted in this paper is feasible.