Estimation of tooth form factor for normal contact ratio asymmetric spur gear tooth

Abstract

To estimate the tooth form factor for a loaded symmetric spur gear tooth, some normalized standards like International Organization for Standardization (ISO) and American Gear Manufacturers Association (AGMA) are available. However, the tooth form factor for a loaded asymmetric spur gear tooth cannot be estimated through the available standards. An asymmetric spur gear tooth is one whose drive side pressure angle is different from the coast side pressure angle. In the present work, the standard ISO B methodology has been adapted suitably for estimating the tooth form factor and the stress correction factor in asymmetric spur gear tooth. Also, the critical root fillet parameters (critical root tooth thickness, bending moment arm and radius of curvature) and the tooth form factor for asymmetric spur gear tooth with several sets of drive side and coast side pressure angles are determined through an adapted ISO method and a comparative study with FEM is also carried out.