35:7 ratio hypoid gear set with tooth contact localization

grabcad

The hypoid gear's tooth surface model is currently at its most precise stage, consisting of two parts—the larger working flank and the narrow undercut area on the root. The working flank is often modeled using specialized software, with numerous suppliers available including myself. In contrast to the working area, the undercut isn't a circular fillet; it results from the tip of the cutter blade or grinding tool in the manufacturing process. Accurate representation of the root undercut is crucial because it impacts stress concentration, significantly affecting the gear tooth's bending strength (which may vary up to 50%) due to the geometry of the root area. By utilizing a correct 3D model, more precise FEA stress calculations can be conducted. To achieve this, I input gear data into Excel and run my VBA macro to generate IGES surfaces for the tooth. This allows easy slot cutting on 3D blanks using these surfaces. The bottom of the tooth is a spline loft, not participating in contact, hence can be accomplished with CAD tools.