This information sheet provides a set of numerical
examples which calculate the geometry factor for
pitting resistance, I , and bending strength, J, for a
variety of gearsets selected todemonstrate thevarious
gear geometries analyzed in AGMA 9084389,
Geometry Factors for Determining the Pitting Resistance
and Bending Strength of Spur, Helical and
Herringbone Gear Teeth. A flow chart is also included
to formalize the calculation procedures for
the numerical examples and toassist in the practical
application of AGMA 9O?-889.
1.1 Numerical examples
Numerical examples were selected to demonstrate
the following conditions: accurate and inaccurate
spur gears, conventional and LACR (low axial contact
ratio) helical gears, internal and external gears,
double helical and herringbone (Sykes) gears and
addendum modification. For simplification purposes
and for demonstrating the effect on resulting
geometry factors, similar examples were selected
with different load locations (example3.1.1 vs3.1.2)
and face widths (example 3.1.3 vs 3.1.4)
The results are presented in tabular form by providing
the numerical results for each equation as presented
in AGMA 908-B89 and appropriate to that
gear geometry. Gear cutter data is presented for
each component in each numerical example. All
gearsets are functional and do not violate any of the
exceptions stated in the scope of AGMA 90?-B89.
The examples used are for demonstration purposes only and are not intended to be recommendations
for gearset design.
1.2 Flow chart
The flow chart provides astep by step procedure for
calculating geometry factors, I and J, using the
equations and instructions from AGMA 908489.
The numerical value tables are formatted to coincide
with the flow chart procedures.
1.3 Exceptions
A procedure for the calculation of bending strength
geometry factor, J, for internal gears has not been
established by AGMA. For this reason, numerical
examples and flow chart procedures for such a calculation
are not included.
AGMA 918-A93-1993 history
1993AGMA 918-A93-1993 Summary of Numerical Examples Demonstrating the Procedures for Calculating Geometry Factors for Spur and Helical Gears