Prediction of the maximum tooth root stress for fatigue analysis of highly crowned spherical gear couplings working at high misaligned conditions

Abstract

Spherical gear couplings efficiently transfer power between highly misaligned rotating shafts, featuring high longitudinal crowning in their design. At high misalignment angles, the contact point shifts across the face width, reducing the number of teeth in contact and increasing the risk of tooth root fatigue failure.

While gear coupling fatigue sizing standards typically address misalignment angles above one degree as special cases, many applications involve misalignment angles exceeding 3°. This paper proposes a surrogate modeling approach to predict maximum tooth root stress for fatigue analysis of spherical gear couplings operating under misaligned conditions. Results indicate that this cannot be predicted in an independent manner from the number of teeth in contact or the effective face width. Consequently, demonstrates that using a single coefficient to account for the effect of the misalignment on load distribution yields optimal results. This research validates the suitability of the presented methodology for predicting tooth root stresses in spherical gear couplings prone to tooth root fatigue failure under high misalignment conditions with a mean error of 0.4%, while it serves as a valuable fast tool for engineers during the design phase.