AGMA 2003-B97

This standard provides a method by which different gear designs can becompared.The formulas in this standard are intended to establish a uniformlyacceptable method for calculating the pitting resistance and bendingstrength capacity of generated straight bevel, zerol bevel and spiralbevel gear teeth; curved and skewed tooth.They apply equally totapered depth and uniform depth teeth.The knowledge and judgment required to evaluate the various ratingfactors come from years of accumulated experience in designing,manufacturing and operating gear units.Empirical factors given in thisstandard are general in nature.AGMA application standards may useother empirical factors that are more closely suited to the particularfield of application.This standard is intended for use by theexperienced gear designer, capable of selecting reasonable values forthe factors.It is not intended for use by the engineering public atlarge.Exceptions.The rating formulas in this standard are not applicable to other typesof gear tooth deterioration such as scuffing, wear, plastic yielding,scoring, case crushing and welding are not applicable when vibratoryconditions exceed the limits specified for the normal operation of thegears (see ANSI/AGMA 6000-B96, Specification for Measurement of LateralVibration on Gear Units).The formulas of this standard are not applicable when any of thefollowing conditions exist: -bevel gears with offset, such as hypoids; -straight and zerol bevel gears with transverse contact ratios,mp (epsilon alpha) less than 1.0; -bevel gears with modified contact ratios, mo (epsilon omicron)less than 1.0; -bevel gears which have a poor contact pattern; -interference exists between tips of teeth and root fillets; -teeth are pointed; -backlash is zero; -bevel teeth finished by forging, casting or sintering.Design considerations to prevent fractures emanating from stress riserson the tooth profile, tip chipping and failures of the gear blankthrough the web or hub should be analyzed by general machine designmethods.ScuffingFormulas for scuffing resistance on bevel gear teeth are not included inthis standard.At the present time, there is insufficient agreementconcerning the method for designing bevel gears to resist scuffingfailure.WearVery little attention and concern have been devoted to the study of geartooth wear.This subject primarily concerns gear teeth with low surfacehardness or gears with with improper lubrication.No attempt has beenmade to cover gear tooth wear in this standard.Plastic yieldingThis standard does not extend to stress levels above those permissiblefor 10(3) cycles, since stresses in this range may exceed the elasticlimit of the gear tooth in bending or in surface compressive stress.Depending on the material and the load imposed, a single load cycleexceeding the stress level for 10(3) life cycles (see clause 16) canresult in plastic yielding of the gear tooth.

ABSTRACT

This standard specifies a method for rating the pitting resistanceand bending strength of generated straight bevel, zerol bevel and spiralbevel gear teeth.A detailed discussion of factors influencing gearsurvival and a calculation method are provided.

Edition:

B97

Published:

01/01/1997

ANSI:

ANSI Approved

Number of Pages:

83