New Approach for Optimum Gear Design. Strengthening Spur Gears by Altering StressDistribution

摘要

A new approach was investigated for achieving lighter spur gears with longerservice life by altering the stress distribution in the gear by introducing hollow and filled holes through the gear face parallel to the shaft axis. The study was conducted using two-dimensional I-DEAS and ANSYS finite element models. The intent was to strategically redistribute the stresses to reduce the critical stress at the root fillet of the tooth. Stresses at the contact area were also monitored. Three strategies were investigated: (1) various hollow hole patterns; (2) press/shrink-fit plugs in the holes to introduce a compressive preload; (3) a high modulus of elasticity insert in a gear blank of low modulus material. The hollow hole patterns reduced the fillet stress up to 5% while increasing contact stress and deflection slightly. Press/shrink-fit plugs which imparted an initial compressive stress at the fillet reduced the stress only slightly more than holes alone. High modulus inserts in a low modulus gear gave the best results, achieving up to 50% stress reduction at the fillet while also reducing the contact stress and tooth deflection.