AGMA 07FTM10 PDF

The dynamic factor has been included in gear design and rating formulas since the 1930's. Its original formulation was based on an assessment of entering tooth impacts, but in modern gear design procedures, where tip relief and lead modifications are common, these impacts may be virtually eliminated. With this elimination, one finds that gear dynamics are mainly excited by steady state phenomenasuch as transmission error, friction and axial shuttling of the mesh force. This paper first provides a historical progression of the dynamic factor equations that are based on impact theory and then discusses when this methodology is appropriate. A sophisticated dynamic finite element simulation of a gear pair with significant spacing errors is used to describe the entering impacts of a spur gear pair. A new steady state dynamic modeling approach is used to demonstrate the effects of the different excitations as well as manufacturing deviations on the predicted dynamic loads.