Frictional stress analysis of spur gear with misalignments

Abstract

Misalignments in gears cause vibrations and contact nonlinearities, which in turn cause load distribution shift on the gear tooth. The load distribution shift of the gear pair results in increased contact and bending stresses with the maximum stresses leaning towards the edge of the face width. These stress changes cause failures and gear performance variations, such as pitting, scuffing, crack initiation and eventually tooth breakage. In this paper, the contact and bending stresses of a misaligned spur gear pair were evaluated with and without friction by employing corresponding analytical methods and finite element method (FEM). Friction coefficient values of 0.1 to 0.3 were used to evaluate the effects of friction on contact and bending stress distribution of a spur gear pair with axial and angular misalignments. The stress concentration was found to be higher at the contact point and at the tooth root of the gear with the augmentation of the misalignment distance and angle. The maximum contact and bending stresses increased by 67.5% and 18.9%, respectively, when axial misalignments were subjected. Similarly, the maximum contact and bending stresses increased by 27.0% and 62.4%, respectively, for angular misalignments. Furthermore, the contact and bending stresses increased proportionally with the increasing coefficient of friction. Finally, the relationships between the normalized stress and misalignments (both axial and angular) were established.