Fatigue Failure of Gears of

The paper embodies results and analysis of an experimental investigation carried out to study fatigue failures of a relatively new type of gearing having teeth of circular-arc profiles. Twenty-one pairs of gears having different helix angles but of the same overlap ratio were tested in a power circulating gear test rig lubricated by oils of different viscosities, running at different speeds and transmitting power exerting constant normal tooth load of 21 KN. Results show that fatigue crack was initiated on the tooth surface at the start of the zone of single contact and propagated to the tooth back till part of or all the tooth was broken. Curves representing fatigue life and its changes with helix angle, oil viscosity and speed are presented and discussed