SOCIETY OFAUTOMOTIVE ENGINEERS, INC. TwoPennsylvania Plaza,NewYork,N.Y.10001 DesignandDevelopment of FluidsforTraction and FrictionTypeTransmissions M.W.Haseltine, I.N.Duling,P.E.Hagstrom andR.J.Stenger Res.andDev.,SunOilCo. D.S.Gates DelawareCountyCommunity College NationalCombined FuelsandLubricants, Powerplant andTruckMeetings St.Louis,Mo. October26-29,1971710837 Downloaded from SAE International by University of Leeds, Monday, August 13, 2018710837 DesignandDevelopment of FluidsforTraction and FrictionTypeTransmissions M.W.Haseltine, I.N.Duling,P.E.Hagstrom andR.J.Stenger Res.andDev.,SunOilCo. D.S.Gates Delaware CountyCommunity College THEADVANTAGES ANDDISADVANTAGES ofvariable andfixedratiotractiondriveshavebeendescribed inthere centliterature(1,2)*.Someoftheadvantages areincreased efficiency, lownoiseleveland,forthevariableunit,acon tinuouslychangeable driveratiowithoutpowerinterruption. Thefactorsmitigating againstthegeneraladoptionofthese deviceshavebeenrelativelylowdurability andlowtorqueca pacity.Thetorquecapacityofthedrivecanbeincreasedby increasing thenormalloadsactingonthecontactelements, butonlywithcorresponding reduction inthelifeoftheele ments.Thissituationisparticularly badbecausethetorque capacityofthedriveisdirectlyproportional tothenormal loadonthecontactsbutthefatiguelifeoftheelementsisin verselyrelatedtoahigherpoweroftheload.Alternatively,thetorquecapacityand/orthedurabilityoftractiondrives canbeincreasedbyincreasing theamountofshearforcesthat canbetransmitted throughthelubricantfilm,thatis,the lubricantmustpossessahighcoefficient oftraction. Asimilarcaseexistsforfrictiondrives.Alubricant witha highcoefficient offrictioncanpermitthesametransmittance oftorquecapacitywithareduction inclutchfaceareaand/or pressure. Frictiondrivesintheformofclutchesfindwideuse inautomatic transmissions, limitedslipdifferentials, wet clutches,wetbrakes,andcamclutches. Previouswork(3-6)hascoveredthetractionevaluation ofa varietyoffluidsfrombothsynthetic andnaturalorigins. Lane(5),usingalimitednumberofcompounds, indicated an apparentinverserelationship betweentractioncoefficient and viscosityindex(V.I.).Hammann, etal.,published datawhich demonstrated theimportance ofcyclohexyl rings.Naphthe nic-typepetroleum oilswerereportedtohavegoodtraction ABSTRACT Thetractioncoefficients foraseriesofhydrocarbon fluids weredetermined andrelatedtotheirstructural andrheological properties. Acontinuous relationship wasfoundbetweenthe coefficient oftractionofthepoly(1-olefin) fluidsandthenum berofcarbonatomsinthemonomerwithamaximumatpoly (1-butene). Afamilyofgem-dimethyl substituted structures wasfoundtoexhibitunusuallyhigh-traction coefficients for viscosityindexlevels. Themannerinwhichcertaintypesofadditivesaffecttrac tionwasdetermined inthedevelopment ofaformulated tractionfluid.Variousstandard testsshowthattheformulated tractionfluidhasverygoodoxidation stability,providesex cellentwearandrustandcorrosionprotection andofferscom parablebearingfatiguelifetoaconventional automatictrans missionfluid.Theeffectonsealsisalsosimilartothatofan ATF. Fieldtestsindicatethattheformulated tractionfluidwill operateeffectively intractiontransmissions, andconventional automatic transmissions; andwilllengthenservicelifeoflim itedslipdifferentials androllerclutches.*Numbers inparentheses designateReferences atendof paper. Downloaded from SAE International by University of Leeds, Monday, August 13, 20182 characteristics, butcarefulfractionation andadetailedexam inationofthecomponents ofsuchanoilfailedtogiveany cluetothestructural ormolecular typeswhichcontribute to ahighcoefficient oftraction(3).Thispaperdescribesthede velopment ofatractionfluidanddiscussesitsproperties and testingwithrespecttoapplication invariousfrictiondrives. COEFFICIENTS OFTRACTION ThetractiondatareportedinFigs.1and2andinTable 1 ofthispaperwereobtainedonthefrictiondrivelubricanttest machinedescribed intheliterature (3).Thecoefficients of tractionvaluesgivenarethoseforconditions of500,000psi m