The standard calculation procedure will use both stock allowance and protruberence defined on the tool profile. The check box on the ’General’ tab-sheet will prevent this during the calculation.
The reference profile dimensions such as addendum and dedendum can be defined in dimensionless multiples of module instead of mm or inch values using this setting. Normally the reference profile is given in factors of module (or 1∕Pnd).
The tolerance method can be defined for the calculation. A choice of AGMA 2000-A88 or AGMA 2015-1-A01 is available from the drop down menu. The scale runs from 15(best) to 3(worst) according to AGMA 2000 or from 2 (best) to 11(worst) according AGMA 2015. In ISO 1328 also the low numbers are for better quality like in AGMA 2015.
Three options are available to define stress cycle factors, Y N for bending strength
and ZN for pitting resistance, based upon the application. For critical service
Y N ≥ 0.8 is used while Y N ≥ 0.9 is used for general applications The option
Y N ≥ 1.0 and ZN ≥ 1.0 is not recommended by AGMA and could be used for
Note: Y N for flanc/induction hardened steel (see chapter 10.2.1.1)
This options allows consideration of the tooth form which may concentrate loading on a specific area of the tooth. Consideration of loading expected at the tip or at HPSTC can be specified. This setting has only an influence on spur and LACR gears.
The reliability factor,(KR), accounts for the statistical distribution of fatigue failures found in materials testing. The required design life and reliability varies considerably with the gear application. Some gears are expendable, and a high risk of failure and a short design life are acceptable. Other applications such as marine gears or gears for power generation, require high reliability and very long life. Special cases such as manned space vehicles demand very high reliability combined with a short design life.
|Reliability R||Application||Failure Frequency|
|0.9||Expendable gears. Motor vehicles.||1 in 10|
|0.99||Usual gear design||1 in 100|
|0.999||Critical gears. Aerospace vehicles||1 in 1000|
|0.9999||Seldom used.||1 in 10000|