The Measurement of Actual Strains at Gear Teeth, Influence of Fillet Radius on Stresses and Tooth Strength

Abstract

With miniature strain gauges having a 0.6 mm gauge length, the strains were measured that occurred at various places in the fillet of spur gears (modulus: m = 10 mm). With this method, gears were tested of varying fillet radii. From the measured results stress concentration factors could be derived that can be used to calculate the actual stresses from the nominal stresses. The measured stresses were compared with the stresses that had been determined photoelastically and analytically according to the method of the finite elements and the integral equation method. As a consequence, it appears to be possible to apply the general strength laws to the gear tooth strength and to superpose the gear tooth stresses upon other stresses (e.g., stresses caused by shrink fitting of a wheel rim).