Three-Dimensional Analysis of Hypoid Gears

A three-dimensional photoelastic analysis using the stress-freezing and slicing techniques was conducted to obtain stress and load distributions in a hypoid gear pair. Precise full-scale plastic models of a gear and pinion were manufactured. A special mounting fixture was designed and built of the same photoelastic plastic as that used for the model. A set-up gage was also designed and manufactured for gaging the gear and pinion settings. Fine adjustments were made by means of shims. The desired contact, calculated to produce maximum fillet stresses, was checked with a marking compound and gaged with a stock-dividing gage. A loading device was used to apply pure torque to the pinion. The assembled model was loaded and taken through the stress-freezing cycle. Subsequently, the teeth under engagement were sliced and analyzed to obtain contact and fillet stress distributions.