Rapid Estimation Method for Gear Bending Fatigue Limit

Abstract

Highlights A calculation method for rapid estimation of gear bending fatigue limit has been established. Based on the rapid test theory and the principle of small sample statistics, combined with the material’s tension–compression S-N curve and step-down loading method, the safe fatigue limit of gears under a certain reliability level is estimated. This method applies gears made from new processes and materials to accelerate process iteration. Abstract The fatigue performance of gears is very important to the safe operation of the transmission system. For gears fabricated using novel materials and advanced manufacturing processes, fatigue limit testing entails significant costs and prolonged timeframes, thereby constraining the rate of design iteration. In this paper, a rapid prediction method for the bending fatigue limit of gears is proposed. This method starts with the S-N curve of the material. Based on the rapid test theory and the principle of small sample statistics, combined with the step-down loading method, the safety fatigue limit of the gear under certain reliability is estimated. Compared with the up-and-down method, the error of this method is within 7.8%, verifying the feasibility of this data processing. At the same time, in this paper, the bending fatigue test of corrosion-resistant nitrided steel gears is carried out, and the bending fatigue limit of corrosion-resistant nitrided steel gears under 99% reliability is quickly obtained. This method holds significant engineering significance in saving test costs, reducing the number of tests, and shortening the development cycle. However, it is currently only applicable to standard spur gears and does not yet consider factors such as the geometric characteristics of helical gears and the corrosion resistance of materials.