On the reduction of windage power losses in gears by the modification of tooth geometry

It has been previously demonstrated both experimentally and numerically that windage power losses (WPL) in high speed transmissions can be mitigated by flanges and/or shrouds close to the gears. However, the gaps between these obstacles and the rotating parts are so small that security during operation can be a problem. In order to overcome this issue, the idea of modifying tooth geometry as proposed by researchers in the early 2010s is investigated in this article. To this end, a numerical approach is first validated based on experimental evidence and then used to study the influence of the size of a tetrahedral shape at tooth edges on WPL. Significant reductions in WPL can be achieved via these tooth modifications but an optimal size has been found beyond which it is not profitable to go since WPL increase for larger modification amplitudes.