Finite Element Contact Analysis Of Meshing Gears In Gearbox Of Wind Turbine Generator

With rapid development of wind turbine industry,the function of more stability and high reliability are required in wind turbine generator system.The in-depth study in the impact of the factors on the gearbox of wind turbine generator is valuable to enhance its load-bearing capacity and transmission stability.This article takes the gear transmission system in the gearbox of megawatt wind turbine generator as the research object,analyses the two factors of its strength and stability,tooth profile modification and friction,using nonlinear finite element method.Firstly,this paper introduces the finite element contact principle,and verifies the effectiveness of the contact element in ANSYS through comparing the results of cylindrical contact analysis and classic Hertz theory,it provides the theoretical support to the contact analysis of the helical gear in the gearbox.Secondly,according to the engagement principle of involutes gear,this paper deduces the involutes curve equation,the dedendum transition curve equation and the spiral curve equation.Builds the 3-dimensional models of helical gear in CAD software and imports to ANSYS for contact finite element analysis.Though the literatures study and result compare of the two kinds of boundaries,it demonstrates the rationality of the boundary selection.Thirdly,combines with tooth profile modification theory,determines the tip easing quantity of helical gear according to the simulation results.Uses two kinds of modification curve and determines the appropriate modification curve under specific condition by comparing the effects.The contact analysis results before and after profile modification show that profile modification can improve the contact pressure distribution,eliminate the stress concentration,enhance the contact strength and decrease the impact vibration caused by base pitch error.The profile modification method in this paper is proved to be feasible.Finally,discusses the formation and distribution of the sliding friction between teeth,and contact pressure formula under friction is derived.Considers effects on the contact pressure and meshing force by setting different friction coefficient in contact analysis.The result comparison of the seven friction coefficient shows that with the increase of friction,meshing force reduces and contact pressure increases.According to the simulation results and theoretical analysis,large friction coefficient is recommended in finite element analysis and friction-effect factors should be considered in contact pressure formula in order to ensure a reliable strength.