Comparative study of stress analysis of gears with different helix angle using the ISO 6336 standard and tooth contact analysis methods. (April 2016)

• Record Type: Journal Article
• Authors: Zhao, Layue; Frazer, Robert C; Shaw, Brian
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 230:Number 7/8(2016)
• Page Start: 1350
• Page End: 1358
• Publication Date: 2016-04
• Subjects: Involute gear -- contact stress -- bending stress -- ISO 6336 -- tooth contact analysis -- contact ratio factor -- form factor -- helix angle factor; Mechanical engineering -- Periodicals; 621.05
• DOI: 10.1177/0954406216639075
• Languages: English
• ISSNs: 0954-4062

Abstract

With increasing demand for high speed and high power density gear applications, the need to optimise gears for minimum stress, noise and vibration becomes increasingly important. ISO 6336 contact and bending stress analysis are used to determine the surface load capacity and tooth bending strength but dates back to 1956 and although it is constantly being updated, a review of its performance is sensible. Methods to optimise gear performance include the selection of helix angle and tooth depth to optimise overlap ratio and transverse contact ratio and thus the performance of ISO 6336 and tooth contact analysis methods requires confirmation. This paper reviews the contact and bending stress predicted with four involute gear geometries and proposes recommendations for stress calculations, including a modification to contact ratio factor Zɛ which is used to predict contact stress and revisions to form factor YF and helix angle factor Yβ which are cited to evaluate bending stress. The results suggest that there are some significant deviations in predicted bending and contact stress values between proposal methods and original ISO standard. However, before the ISO standard is changed, the paper recommends that allowable stress numbers published in ISO 6336-5 are reviewed because the mechanisms that initiate bending and contact fatigue have also changed and these require updating.