1、AGMAINFORMATIONSHEET(This Information Sheet is NOT an AGMA Standard)AGMA925-A03AGMA 925-A03AMERICAN GEAR MANUFACTURERS ASSOCIATIONEffect of Lubrication on Gear SurfaceDistressiiEffect of Lubrication on Gear Surface DistressAGMA 925-A03CAUTION NOTICE: AGMA technical publications are subject to consta
2、nt improvement,revision or withdrawal as dictated by experience. Any person who refers to any AGMAtechnicalpublicationshouldbesurethatthepublicationisthelatestavailablefromtheAs-sociation on the subject matter.Tables or other self-supporting sections may be quotedor extracted.Credit linesshouldread:
3、 ExtractedfromAGMA925-A03,EffectofLubricationonGearSurfaceDistress,withthepermissionofthepublisher,theAmericanGearManufacturersAssociation,500Mont-gomery Street, Suite 350, Alexandria, Virginia 22314.Approved March 13, 2003ABSTRACTAGMA 925-A03 is an enhancement of annex A of ANSI/AGMA 2101-C95. Vari
4、ous methods of gear surfacedistressareincluded,suchasscuffingandwear,andinaddition,microandmacropitting. Lubricantviscometricinformationhasbeenadded,ashasDudleysregimesoflubricationtheory. AflowchartisincludedinannexA,GaussiantheoryinannexB,asummaryoflubricanttestrigsinannexC,andanexamplecalculation
5、inannexD.Published byAmerican Gear Manufacturers Association500 Montgomery Street, Suite 350, Alexandria, Virginia 22314Copyright 2003 by American Gear Manufacturers AssociationAll rights reserved.No part of this publication may be reproduced in any form, in an electronicretrieval system or otherwis
6、e, without prior written permission of the publisher.Printed in the United States of AmericaISBN: 1-55589-815-7AmericanGearManufacturersAssociationAGMA 925-A03AMERICAN GEAR MANUFACTURERS ASSOCIATIONiiiContentsPageForeword iv.1 Scope 1.2 References 23 Symbols and units 24 Gear information 55 Lubricat
7、ion 9.6Scufing 177 Surface fatigue (micro- and macropitting) 22.8 Wear 26.Bibliography 49.AnnexesA Flow chart for evaluating scuffing risk and oil film thickness 31B Normal or Gaussian probability 39C Test rig gear data 41D Example calculations 43.Figures1 Distances along the line of action for exte
8、rnal gears 6.2 Transverse relative radius of curvature for external gears 7.3 Load sharing factor - unmodified profiles 8.4 Load sharing factor - pinion driving 85 Load sharing factor - gear driving 8.6 Load sharing factor - smooth meshing 9.7 Dynamic viscosity versus temperature for mineral oils 13
9、8 Dynamic viscosity versus temperature for PAO-based syntheticnon-VI-improved oils 149 Dynamic viscosity versus temperature for PAG-based synthetic oils 1510 Dynamic viscosity versus temperature for MIL Spec. oils 1611 Pressure-viscosity coefficient versus dynamic viscosity 16.12 Example of thermal
10、network 19.13 Contact temperature along the line of action 20.14 Plot of regimes of lubrication versus stress cycle factor 25.15 Probability of wear related distress 27.Tables1 Symbols and units 22 Data for determining viscosity and pressure-viscosity coefficient 12.3 Mean scuffing temperatures for
11、oils and steels typical of the aerospaceindustry 204 Welding factors, XW215 Scuffing risk 21.6 Stress cycle factor equations for regimes I, II and III 257 Calculation results 29.AGMA 925-A03 AMERICAN GEAR MANUFACTURERS ASSOCIATIONivForewordThe foreword, footnotes and annexes, if any, in this documen
12、t are provided forinformational purposes only and are not to be construed as a part of AGMA InformationSheet 925-A03, Effect of Lubrication on Gear Surface Distress.Thepurposeofthisinformationsheetistoprovidetheuserwithinformationpertinenttothelubrication of industrial metal gears for power transmis
13、sion applications. Itis intendedthatthis document serve as a general guideline and source of information about conventionallubricants, their properties, and their general tribological behavior in gear contacts. Thisinformation sheet was developed to supplement ANSI/AGMA Standards 2101-C95 and2001-C9
14、5. Ithasbeenintroducedasanaidtothegearmanufacturingandusercommunity.Accumulation of feedback data will serve to enhance future developments and improvedmethods to evaluate lubricant related wear risks.It was clear from the work initiated on the revision of AGMA Standards 2001-C95 and2101-C95 (metric
15、 version) that supporting information regarding lubricant properties andgeneral tribological knowledge of contacting surfaces would aid in the understanding ofthesestandards. Theinformationwouldalsoprovidetheuserwithmoretoolstohelpmakea more informed decision about the performance of a geared system
16、. This informationsheetprovidessufficientinformationaboutthekeylubricantparameterstoenabletheuserto generate reasonable estimates about scuffing and wear based on the collectiveknowledge of theory available for these modes at this time.In 1937 Harmon Blok published his theory about the relationship
17、between contacttemperature and scuffing. This went largely unnoticed in the U.S. until the early 1950swhen Bruce Kelley showed that Bloks method and theories correlated well withexperimental datahe hadgenerated onscuffing ofgear teeth. TheBlok flashtemperaturetheory began to receive serious consider
18、ation as a predictor of scuffing in gears. Themethodology and theories continued to evolve through the 1950s with notablecontributions from Dudley, Kelley and Benedict in the areas of application rating factors,surface roughness effects and coefficient of friction. The 1960s saw the evolution of gea
19、rcalculations and understanding continue with computer analysis and factors addressingload sharing and tip relief issues. The AGMA Aerospace Committee began using all theavailable information to produce high quality products and help meet its long-term goal ofmanned space flight. R. Errichello intro
20、duced the SCORING+ computer program in 1985,which included all of the advancements made by Blok, Kelley, Dudley and the AerospaceCommittee to that time. It became the basis for annex A of ANSI/AGMA 2101-C95 and2001-C95 which helped predict the risk of scuffing and wear. In the 1990s, this annexforme
21、d the basis for AGMAs contribution to ISO 13989-1.Just as many others took the original Blok theories and expanded them, the TribologySubcommittee of the Helical Gear Rating Committee has attempted to expand the originalannex A of ANSI/AGMA 2001-C95 and 2101-C95. Specifically, the subcommitteetarget
22、edtheeffectlubricationmayhaveongearsurfacedistress. Asdiscussionsevolved,itbecame clear that this should be a stand alone document which will hopefully serve manyothergeartypes. Thisshouldbeconsideredaworkinprogressasmoreislearnedaboutthetheories and understanding of the various parameters and how t
23、hey affect the life of thegear. Some of these principles are also mentioned in ISO/TR 13989-1.AGMA 925-A03 was approved by the AGMA Technical Division Executive Committee onMarch 13, 2003.Suggestionsforimprovementofthisdocumentwillbewelcome. TheyshouldbesenttotheAmericanGearManufacturersAssociation,
24、500MontgomeryStreet,Suite350,Alexandria,Virginia 22314.AGMA 925-A03AMERICAN GEAR MANUFACTURERS ASSOCIATIONvPERSONNEL of the AGMA Helical Rating Committee and Tribology SubCommitteeChairman: D. McCarthy Dorris Company.Vice Chairman: M. Antosiewicz The Falk CorporationSubCommittee Chairman: H. Hagan T
25、he Cincinnati Gear CompanyCOMMITTEE ACTIVE MEMBERSK.E. Acheson The Gear Works-Seattle, IncJ.B. Amendola MAAG Gear AGT.A. Beveridge Caterpillar, Inc.M.J. Broglie Dudley Technical Group, IncA.B. Cardis Exxon Mobil Research.M.F. Dalton General Electric Company.G.A. DeLange Prager, IncorporatedD.W. Dudl
26、ey ConsultantR.L. Errichello GEARTECH.D.R. Gonnella Equilon Lubricants.M.R. Hoeprich The Timken CompanyO.A. LaBath The Cincinnati Gear Co.G. Lian Amarillo Gear Company.J.V. Lisiecki The Falk Corporation.L. Lloyd Lufkin Industries, Inc.J.J. Luz General Electric CompanyD.R. McVittie Gear Engineers, In
27、cA.G. Milburn Milburn Engineering, Inc.G.W. Nagorny Nagorny the calculations areofferedtohelpassessthepotentialriskinvolvedwithagivenlubricantchoice. Flowchartsareincludedasaids to using the equations.This information sheet is a supplement to ANSI/AGMA 2101-C95 and ANSI/AGMA 2001-C95. Ithas been int
28、roduced as an aid to the gear manufac-turing and user community. Accumulation of feed-backdatawillservetoenhancefuturedevelopmentsand improved methods to evaluate lubricant relatedsurface distress.ItwasclearfromtheworkontherevisionofstandardANSI/AGMA 2001-C95 (ANSI/AGMA 2101-C95,metric version) that
29、 supporting information regard-ing lubricant properties and general tribologicalunderstanding of contacting surfaces would aid inunderstanding of the standard and provide the userwith more tools to make an informed decision abouttheperformanceofagearedsystem. Oneofthekeyparameters is the estimated f
30、ilm thickness. This isnot a trivial calculation, but one that has significantimpact on overall performance of the gear pair. It isconsidered in performance issues such as scuffing,wear, and surface fatigue. This information sheetprovides sufficient information about key lubricantparameters to enable
31、 the user to generate reason-able estimates about surface distress based on thecollective knowledge available.Blok 1 published his contact temperature equationin1937. Itwentrelatively unnoticedintheU.S. untilKelley 2 showed that Bloks method gave goodcorrelation with Kelleys experimental data. Bloks
32、equation requires an accurate coefficient of friction.Kelleyfoundit necessaryto couplethe coefficientoffriction to surface roughness of the gear teeth.Kelleyrecognizedtheimportanceofloadsharingbymultiplepairsofteethandgeartoothtiprelief,buthedidnotofferequationstoaccountforthosevariables.Dudley 3 mo
33、dified Kelleys equation by addingderating factors for application, misalignment anddynamics. Heemphasizedtheneedforresearchoneffects of tip relief, and recommended applyingBloks method to helical gears.In 1958, Kelley 4 changed his surface roughnessterm slightly.Benedict and Kelley 5 published their
34、 equation forvariablecoefficientoffrictionderivedfromdisctests.TheAGMAAerospaceCommitteebeganinvestigat-ing scuffing in 1960, and Lemanski 6 publishedresults of a computer analysis that contains data for90 spur and helical gearsets, and formed the termsfor AGMA 217.01 7, which was published in 1965.
35、It used Dudleys modified Blok/Kelley equation andincluded factors accounting for load sharing and tiprelief.AGMA 925-A03 AMERICAN GEAR MANUFACTURERS ASSOCIATION2TheSCORING+computerprogram8wasreleasedin 1985. It incorporated all advancements made byBlok,Kelley,Dudley andAGMA217.01. Inaddition,it adde
36、d several improvements including:- Helical gears were analyzed by resolving theload in the normal plane and distributing thenormal load over the minimum length of thecontact lines. The semi-width of the Hertziancontactbandwascalculatedbasedonthenormalrelative radius of curvature;- Deratingfactorsfor
37、application,misalignmentand dynamics were explicit input data;- Options for coefficient of friction were part ofinput data, including a constant 0.06 (as pre-scribed by Kelley and AGMA 217.01), a constantunder user control, and a variable coefficientbased on the Benedict and Kelley equation.SCORING+
38、 and AGMA 217.01 both use the samevalue for the thermal contact coefficient ofBM= 16.5 N/mms0.5K, and they calculate thesame contact temperature for spur gears if allderating factors are set to unity.Annex A of ANSI/AGMA 2101-C95 and ANSI/AGMA 2001-C95 was based on SCORING+ andincluded methods for p
39、redicting risk of scuffingbased on contact temperature and risk of wearbased on specific film thickness.This information sheet expands the information inannexAofANSI/AGMA2101-C95andANSI/AGMA2001-C95toincludemanyaspectsofgeartribology.2 ReferencesThe following standards contain provisions whichare re
40、ferenced in the text of this information sheet.Atthetimeofpublication,theeditionsindicatedwerevalid. All standards are subject to revision, andparties to agreements based on this document areencouraged to investigate thepossibility ofapplyingthe most recent editions of the standards indicated.ANSI/A
41、GMA 2001-C95, Fundamental Rating Fac-tors and Calculation Methods forInvolute SpurandHelical Gear TeethANSI/AGMA 2101-C95, Fundamental Rating Fac-tors and Calculation Methods forInvolute SpurandHelical Gear Teeth (Metric Edition)ANSI/AGMA1010-E95,AppearanceofGearTeeth- Terminology of Wear and Failur
42、eISO 10825:1995, Gears - Wear and Damage toGear Teeth - Terminology3 Symbols and unitsThe symbols used in this document are shown intable 1.NOTE: The symbols and definitions used in this docu-ment may differ from other AGMA standards.Table 1 - Symbols and unitsSymbol Description Units Where firstuse
43、dA Dimensionless constant - - Eq 61awOperating center distance mm Eq 4B Dimensionless constant - - Eq 61BMThermal contact coefficient N/mm s0.5K 6.2.3BM1, BM2Thermal contact coefficient (pinion, gear) N/mm s0.5K Eq 84b Face width mm Eq 23bHiSemi-width of Hertzian contact band mm Eq 57CA. CFDistances
44、 along line of action mm 4.1.2CRavgxSurface roughness constant - - Eq 85c Parameter for calculating o- - Eq 69cM1, cM2Specific heat per unit mass (pinion, gear) J/kg K Eq 89, 90DiInternal gear inside diameter mm 4.1.2d Parameter for calculating o- - Eq 69(continued)AGMA 925-A03AMERICAN GEAR MANUFACT
45、URERS ASSOCIATION3Table 1 (continued)Symbol Description Units Where firstusedE1,E2Modulus of elasticity (pinion, gear) N/mm2Eq 58ErReduced modulus of elasticity N/mm2Eq 57FtActual tangential load N Eq 42(Ft)nomNominal tangential load N Eq 40FwnNormal operating load N Eq 43G Materials parameter - - E
46、q 65g Parameter for calculating o- - Eq 69HciDimensionless central film thickness - - Eq 65h Thickness of element measured perpendicular to flow m Eq 59hciCentral film thickness mm Eq 75hminMinimum film thickness mm Eq 102K Flash temperature constant - - Eq 84KDCombined derating factor - - Eq 41KmLo
47、ad distribution factor - - Eq 41KoOverload factor - - Eq 41KvDynamic factor - - Eq 41k Parameter for calculating - - Eq 74ksumpParameter for calculating M- - Eq 91LxFilter cutoff of wavelength x mm Eq 77LminMinimum contact length mm Eq 25mnNormal module mm Eq 2n1Pinion speed rpm Eq 33N Number of loa
48、d cycles cycles Fig 14naFractional (non-integer) part of - - Eq 25nrFractional (non-integer) part of - - Eq 25P Transmitted power kW Eq 40P(x)Probability of survival - - 8.2.2p Pressure N/mm2Eq 64pbnNormal base pitch mm Eq 10pbtTransverse base pitch mm Eq 9pxAxial pitch mm Eq 11Q Tail area of the no
49、rmal probability function - - Eq B.2Q(x)Probability of failure - - 8.2.2RavgxAverage of the average values of pinion and gear roughness mm Eq 87Ra1x, Ra2xAverage surface roughness (pinion, gear) at Lxmm Eq 78RqxRoot mean square roughness at Lxmm Eq 79RqxavgArithmetic average of Rq1xand Rq2xat Lxmm Eq 99Rq1x, Rq2xRoot mean square roughness at Lx(pinion, gear) mm Eq 99r1, r2Standard pitch radius (pinion, gear) mm Eq 2, 3ra1, ra2Outside ra
