Analysis of tooth stiffness of spur gears by finite element method

Gears have many crucial properties that must be met in order to perform their function properly. Stiffness of gear is very important characteristic, it relates to deflection which is inevitable under transmitted forces. Determining stiffness of gears is necessary in terms of; gear design, noise and vibrations and optimization processes. Too low or too high stiffness may cause serious transmission errors. A lot of parameters affect stiffness almost relate to gear material, design and conditions of the motion and applied forces. In this study calculations of stiffness has been presented by 2-D modeling of involute spur gears. The Finite Element Method (FEM) has been used which has very helpful role because of its high capability on simulating complex gear mesh process. Values of tooth pair stiffness and mesh stiffness have been obtained. Effects of some macro geometrical parameters on stiffness have been investigated. Quasi static FE analysis has been performed by MARC simulation software program of MSC Nastran for non-linear analysis. Obtained results showed how stiffness behavior changes with different parameters of gear. The comparisons of the FEA results revealed even the small influences caused by the difference in studied parameters. The use of FE analysis to determine the effectiveness of a profile modification gave clear results that can greatly help to proceed with proposed design. To validate results, some of FEA results were compared with software results which gave consistent values. Keywords: Spur gear, stiffness, tooth pair stiffness, mesh stiffness, transmission error, FEM.