Wear simulation of worm gears based on an energetic approach

Wear phenomena in worm gears are dependent on the size of the gears. Whereas larger gears are mainly affected by fatigue wear, abrasive wear is predominant in smaller gears. In this context a simulation model for abrasive wear of worm gears was developed, which is based on an energetic wear equation. This approach associates wear with solid friction energy occurring in the tooth contact. The physically-based wear simulation model includes a tooth contact analysis and tribological calculation to determine the local solid tooth friction and wear. The calculation is iterated with the modified tooth flank geometry of the worn worm wheel, in order to consider the influence of wear on the tooth contact. Experimental results on worm gears are used to determine the wear model parameter and to validate the model. A simulative study for a wide range of worm gear geometries was conducted to investigate the influence of geometry and operating conditions on abrasive wear.

Wheel profile optimization procedure to minimize flange wear considering profile wear evolution

This study aims to develop a wheel profile optimization procedure to minimize flange wear considering the wear evolution. To this end, the wheel wear simulation capability is integrated into the profile optimization framework such that a total material loss can be minimized under design constraints. This allows for the wear reduction to be maintained over an extended traveling distance, while an optimized profile, minimizing the frictional energy for only the initial profile, would not ensure the optimum performance after the profile wear becomes significant. Furthermore, to enable a balanced mitigation of the profile wear and surface damage, the damage index model is introduced to the weighted objective function, considering profile wear evolution. Using flange wear tests with a scaled roller test rig, wear reduction of the optimized profile is experimentally validated. The wear simulation results agree with the test data. It is demonstrated that the flange wear and tread surface damages are reduced simultaneously over an extended traveling distance using the profile optimization procedure developed in this study.