Modeling the effect of misalignment and tooth microgeometry on helical gear pair in mesh

Understanding the effect of misalignment and microgeometry is important for gear designers and those have the main interest is gear manufacturing and maintenance. Unavoidable misalignment and microgeometry are both important factors to be considered in gear design which influence the resulted stresses, transmission error, and dynamic response. Analyzing the stress concentration on the tooth root and tooth flank areas is important to predict the failure modes that may occur. The current research work concentrates on modeling engaged gear teeth, analyzing the generated stresses and shows the importance of introducing the micro-geometry modifications. To do so, three different cases have been studied. The first case (case 1) considers the basic microgeometry modifications, the second case (case 2) considers the misalignment effect, and the last case (case 3) is to add some more micro-geometry modifications to compensate for the misalignment effect. It was observed that the gear calculating tools resulted in significantly higher stresses than the FE software. The obtained results from different software tools have been discussed to understand the differences for the three studied cases. However, the results from case 2 as compared to case 1 showed that the introduced misalignment results in shifting the stress pattern into one side of the gear tooth and significantly higher stresses than case 1. Case 3 showed that the use of microgeometry modifications can result in compensating the effect of the misalignment in operation.