Combining gear design with manufacturing process decisions

Introduction The layout of gear drives is a challenging process. Lifetime, noise, losses and other criteria must be considered. In the design process, first the overall geometry (e.g., center distance and outer dimensions of gear pairs) must be determined. Then macro geometry (e.g., module, helix angle, number of teeth, and reference profile) must be defined and optimized based on the requested design requirements. Finally, the micro geometry (e.g., profile and lead modifications) must be sized for optimum gear mesh behavior. In this complex process a design engineer is focused on finding the best gear layout and will not often consider manufacturing constraints. It’s only after the manufacturing department gets the gear design data that the most efficient manufacturing process is evaluated and manufacturing costs are considered. Today cost-efficient gear manufacturing processes are available. But whether a process — for example, power skiving or honing — is possible or not depends on certain gear and pinion geometry conditions and interference contours. Often, only a small change in the macro geometry would permit the use of a more productive or less-costly manufacturing process. If the production department requests a change to the gear geometry, the design process often must be restarted, making the process time-consuming. Instead, an often-repeated request from production departments is to integrate certain manufacturing experience into the design process. Frequently designers are not familiar with manufacturing processes and so it is beneficial for them to have access to simple manufacturing information within their design software. This can, for example, determine if an intended manufacturing process is feasible or not.