The Engaging Load And Axial Modification Of Helical Gear Used In Increasing Gearbox Of Wind Turbine Generator

With the Wind Turbine Generator develops towards High-power, more requirements are put forward on the Increasing Gearbox of Wind Turbine Generator. Therefore, further investigation on the Increasing Gearbox's gear-driven system of Wind Turbine Generator, especially the modification technology of helical gear, is valuable to enhance its load-bearing capacity and transmission stability.This thesis does some research on the Increasing Gearbox's gear-driven system of Megawatt Wind Turbine Generator which is imported by DHI·DCW Group CO., LTD. Thesis also proposes an axial modification technology when helical gear with multi-tooth are meshing that can do a lot technical supports on exploiting High-power's Wind Turbine Generator. This thesis builds a 3D parametric finite element model of helical gear in ANSYS software and uses the contact method to analyze the loading distribution of helical gear. Combining the conjugate engagement principle of helical gear, a method to modify the angle of helical gear has been put forward.Firstly, this thesis introduces the finite element contact principle which provides the theoretical support to the contact analysis of the engaging load of helical gear on the Increasing Gearbox. According to the engagement principle of involutes gear, thesis deduces the involutes curve equation, the involutes curve helicoids equation, the Dedendum transition curve and the contact ratio equation and then uses the ANSYS Parametric Design Language to build the 3D parametric finite element model of helical gear in ANSYS software. By write program with VB, the grid of the contact surface of finite element model is refined and the helical gear tooth is modified. The contact pair of contact analysis is established, and the restrain and load of the helical gear is applied.Secondly, combining the deformation compatibility condition and the force equilibrium of the engaging helical gear, a linear equations with node force and engagement deformation is established. The loading distribution of helical gear is analyzed theoretically, on the basis of that, the load distribution among gear teeth and the longitudinal load distribution of the helical gear is calculated by the ANSYS finite element contact analysis, by comparison of the analysis result, the gear deflecting loading is existent when the helical gear is engaging. Then thesis analyzes the effect of contact parameter on analysis result. Finally, the reason of gear deflecting loading is analyzed according to the helical gear conjugate engagement principle and thesis proposes the scheme of helix angle modification. Then the helix angle modification of helical gear is optimized by the finite element contact method so as to make sure the optimum modification amount and the strength of helical gear is compared before and after helix angle modification. The analysis of helix angle modification shows that the engaging load distribution of helical gear has great improve after helix angle modification and the transmission quality of helical gear has been great enhanced. It is also showed that the helix angle modification of helical gear by finite element contact analysis in the thesis is feasible.The research on the helical gear engaging load and axial modification of Increasing Gearbox is great valuable and significance for a further research of gear-driven kinematical capability and integrated tooth modification.