Comparative Study Of ISO And AGMA Gear Strength Rating Methods For Involute Cylindrical Gears

Gear strength rating standard is one of the criteria for measuring gear quality. Discrepancies exist in different calculation methods of international and advanced foreign standards for involute cylindrical gears. This thesis makes a comprehensive comparative study of International Standards Organization (ISO) standard and American Gear Manufacturers Association (AGMA) standard, which are widely applied in scientific research and engineering practice, in order to rationally evaluate different standards'calculation methods and results as well as efficiently apply standards to engineering practice.First an overview of current research on comparison between different gear strength rating standards was presented,and deficiencies of current research were pointed out; then discrepancies between ISO and AGMA standards were analyzed from theoretical aspect, comparison between ISO formulas and AGMA formulas was made, parameters and correction factors applied in the two standards were classified and compared by their meanings and influence factors they consider; finally 18 representative gear meshes chosen by means of orthogonal test were calculated, effects of variation gear design parameters on strength rating results of the two standards were analyzed by range analysis of orthogonal test, strength rating results of the two standards were compared, comparative study about the value of parameters and correction factors of the two standards and their effects on gear rating results was carried out, main cause of the discrepancies in gear rating results of the two standards was analyzed.The study indicates that neither of the two standards is more conservative than the other one, and the strength rating results of AGMA standard are more sensitive to the change of gear design parameters. The study also indicates that differences in parameters and correction factors applied in the two standards result in the discrepancies in gear rating results of the two standards; parameters and correction factors between the two standards are different because the two standards focus differently on theoretical derivation, experimental data and empirical formulas, which makes the two standards apply different strength theory and calculation methods in the calculation of some parameters and correction factors, moreover, gear experiments of the two standards were carried out under different experimental condition,which lead to the differences between experimental data of the two standards.