7 - Detailed Gear Stressing

Abstract

This chapter outlines the AGMA standards for the calculation of bending and contact stresses in spur gears. The objective of this chapter is to determine the AGMA bending stress for a spur gear, to determine the AGMA contact stress, to determine the allowable bending and contact stresses, to determine a factor of safety, and to propose a design strategy for spur gears. This chapter has introduced the AGMA equations for modelling bending and contact stresses in spur gears. The section concentrates on analyzing whether failure because of bending and contact stresses in a gear set is likely. The second section outlines a relatively simple relationship for contact stresses prior to the introduction of the current AGMA equations for bending and contact stresses. The AGMA equations rely on the evaluation of a significant number of factors and geometrical parameters, which depend on the specific geometry and materials concerned. In this chapter, the basic approach is outlined for 20° pressure angle for full depth teeth spur gears only. A general strategy for gear design is outlined in the final section.