Calculation of tooth bending strength and surface durability of internal spur gear drives

In this paper the determinant load conditions for bending and pitting calculations, for involute, internal spur gears have been established. Calculations are based on a new model of load distribution, which takes into account the changing rigidity of the pair of teeth along the path of contact. This model has been obtained from the minimum elastic potential criterion, resulting in non-uniform load sharing among spur tooth pairs in simultaneous contact. As a result, the theoretical values of both bending and pitting nominal stresses are given, which may be suitable for standardization purposes.