Computer aided analysis of involute spur gears with asymmetric teeth

Abstract

In this study, involute spur gears with asymmetric teeth are investigated. The asymmetry means that pressure angles are different for the drive and coast sides. The aim of asymmetric tooth is to improve the performance of gears such as increasing the load carrying capacity or reducing noise and vibration. In Literature, there are two different applications for involute gears with asymmetric teeth. The difference between them is the selection of pressure angles for drive side and coast side. Since the load capacity of the involute gear mainly depends on the pressure angle, the determination of pressure angles is very important. Computer programs, different from previous studies which is considering tooth number and drive side pressure angle, have been developed for the minimizitation of bending tooth stress and the comparison of spur gears with asymmetric teeth and addendum modification in regard to bending strength by using MatLab program language. Since asymmetric tooth is not standard, the tooth model, which was introduced by DIN 3990 /Method C and ISO/TC 60, has been adjusted for asymmetric tooth by the authors. The determination of the tooth form and stress concentration factors for asymmetric tooth has been accomplished for each different parameter (pressure angles, tool radius, rack shift etc.). The obtained results that agree with FEA results presented graphically in this study. Spur gears with asymmetric teeth have been also considered for dynamic loads. The effects of different gear design parameters are investigated. The sample results, which were obtained by using the developed computer programs, are illustrated with numerical examples.