Chapter 9
GEARCALC in general

The GEARCALC windows version has several parts. First we have the GEARCALC wizard for the sizing of a new gear pair. Then we have three pages for the analysis of a gear pair. The input data of the wizard is independent of the data for analysis. Only if you accept the results from the wizard the data is transfered from the wizard to the analysis part of the software. All the graphics displayed are for the data for the analysis part of the software.

Usually you will start a new design in the GEARCALC wizard (see chapter 10). The wizard will guide you with several pages to get a design that suits your purpose. After accepting the result you can do further analysis on strength using the AGMA 2001/2101 page (see chapter 12), you can do a lifetime analysis using a load spectrum on the page Lifetime (see chapter 13) or an analysis for scoring or wear on the AGMA 925 page (see chapter 14).

If you want to modify the geometry afterwards you can either go through the wizard again. This can be done quickly because all the inputs are saved. Or you change the geometry directly on the AGMA 2001/2101 page, if you know what you want to change.

For the analysis there are different reports for the three pages. So you can get a geometry and strength report, a report for the lifetime calculation and also a report for AGMA 925 calculation.

AGMA 2001 is used if US customary units are selected while AGMA2101 (metric edition of AGMA 2001) is used if metric units are selected. The formula signs in this manual are given as in AGMA 2001 and in brackets behind you will find the symbols as used in the metric system.







AGMA2001
AGMA2101
Description See
SymbolUnits SymbolUnits






C in a mm Operating center distance 12.5






Ce KHme Mesh alignment correction factor 12.21.4






Cma KHma Mesh alignment factor 12.21.3






Cmc KHmc Lead correction factor 12.21.1






Cmf K Face load distribution factor 12.21






Cmt K Transverse load distribution factor 12.21.6






Cpm KHpm Pinion proportion modifier 12.21.2






CH ZW Hardness ratio factor for pitting resistance






Km KH Load distribution factor 12.21






Ko Ko Overload factor 12.20






Kv Kv Dynamic factor 12.22






KR Y Z Reliability factor 11.2.6






F in b mm Net face width 12.7






L hours L hours Life 12.19






mG u Gear ratio 1






mp εα Transverse contact ratio






mF εβ Axial contact ratio






NP z1 Number of teeth in pinion 12.6






NG z2 Number of teeth in gear 12.6






nP rpm ω1 rpm Pinion speed 12.18






q q Number of contacts per revolution 12.25






P hp P kW Transmitted power 12.17






Pnd 1/in Normal diametral pitch 12.2






mn mm Normal module 12.1






SH SH Safety factor – pitting 11.3






SF SF Safety factor – bending 11.3






sac lb/in2σ HP N/mm2Allowable contact stress number






sat lb/in2σ FP N/mm2Allowable bending stress number






sc lb/in2σ H N/mm2Contact stress number






st lb/in2σ F N/mm2Bending stress number






ψ β Helix angle at generating pitch diameter 12.4






φn α n Normal pressure angle 12.3