Gear-Tooth Stress Calculation Method for Heavily Crowned Gear

Abstract

Gear rating is decided by tooth strength, surface durability and scoring resistance of gear pair. In Japan, in order to prevent gear-tooth breakage induced by end tooth bearing, gears are often crowned heavily.The stress calculation method for this heavily crowned gear is already proposed by one of the authors, but this calculation method is very troublesome. So, it is desirable that a simple and easy stress calculation method for crowned gear be established.For this reason, the authors proposed a simple and easy calculation method for maximum longitudinal tooth stress of crowned gear using the infinite length cantilever plate theory applied with moment-image method introduced Wellauer, E. J. and Seireg, A.. This simple and easy calculation method is a method by which the maximum gear-tooth stress is obtained as the stress of uniformly loaded spur gear divided by the crowning factor. The crowned gear tooth stress is estimated for the gear-tooth load distribution which is obtained by solving the contact problem about two elastic ellipsoids substituted for meshing gear-tooth.The authors demonstrated by experiments that this crowned gear-teeth stress calculation method is quite proper. Moreover, they proposed the stress calculation method for a special state of end tooth bearing of crowned gear, and proved the practicability of this method by experiments.