The Transmission Optimization And Reliability Design Of WN Gears

Circular arc gear is named for its tooth working profile curve is arc. In the international,it is called Wildhaber-Novikon Gear, named WN gear for short. Because of its high loadcarrying capacity, high tooth contact strength and tooth root bending strength compared withinvolutes gear, it is particularly important with high theoretical value and practicalsignificance to optimize tooth profile parameters, analyze the stress and study the reliabilitywith the WN gear, using advanced design calculation methods and computer technology.This paper was supported by National Natural Science Foundation of China (51075047).It takes the GB/T12759-1991standard WN gear for research object, and the main content isas follows:First of all, the tooth surface meshing theory is applied to the WN gear transmissionbased on the space meshing theory in this paper. The WN gear tooth surface equation isdeduced according to meshing theory, then the end face tooth profile equation of WN gear canbe got; according to the research on meshing characteristics and the toothed parametersselection principle of WN gear, it is fully prepared for the optimization and solid modelingnext.Second, the nonlinear constrained optimization problems are solved using sequentialquadratic programming (SQP) of MATLAB optimization toolbox. The gear tooth parametersare optimized using computational methods and computer technology, so a complete methodof tooth profile parameters optimization design is formalized. Meanwhile, the relatedparameters of the design are disposed with the least squares fitting, to improve designefficiency and numerical accuracy. And the impact of the various toothed parameters to toothcontact strength and bending strength is illustrated by specific examples, providingapplication basis for WN gear CAD design.Third, the bending stress is analyzed for WN gear in its static module, using the finiteelement analysis software ANSYS. The position of maximum bending stress, the stresschanges with upload position and the trends of stress caused by changes along the tooth widthdirection are analyzed of according to the last stress and strain diagram, providing referencebasis for bending stress conditions of the teeth suffered in the actual work.Finally, a brief analysis of WN gear failure mode is given, providing theoretical guidanceto avoid unnecessary gears failure and damage. The reliability design method is summarizedof WN gear under both cases of tooth surface contact stress and tooth root bending stress,according to reliability design theory and the knowledge of the common cylindrical gear. Thereliability design process is illustrated by specific examples. The reliability calculation method is simple and clear, easy to apply.The results of this study provide a certain reference for tooth profile parameteroptimization, stress analysis and reliability studies of WN gear.