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causedbydynamicinstabilityofthevibrationsystemcomposedofdiscbrake，knuckIeandsuspension，ThisisanalyzedbyflutterofthevibrationsystemundersmaI1disturbanceoffrictionfOrcevariation，whichisshownin

references[4]ａｎｄ［５１Recently,FEAnalysisofbrakesqueal［6]isappliedfOrbrakedesignrefinementsfO「brakesqueaIreduction、ButitwilIbesometimesdifficulttomodifythevibrationsystemfOrdynamicstabilityinallvibrationmodes・ＴｈｅｎｉｔｗｉＩＩｂｅｍｏｒｅｉｍｐｏｒｔａｎｔｔｏｒｅｄucebrakefrictionforcevariation、ＴｈｉｓｐａｐｅｒｓｈｏｗｓｔｈｅｃｏｎｃｅｐｔｏｆｐａｄｍaterialsdesignfOrhigherperfOnnanceandIessbrakesqueaLwhichisbasedontheMDsimuIationandexperimentresults．

ＡＢＳＴＲＡＣＴ

Brakesquealiscausedbydynamicinstability，whichisinfluencedbyitsdynamicunstablestructureandsmalldisturbanceoffrictionfOrcevariation、RecentIy，ＦＥ

ＡｎａＩｙｓｉｓｏｆｂ｢akesqueaIisappIiedfOrbrakedesignrefinements，whichisbasedondynamicinstabiIitytheo｢y・ＡｓｓａｍｅａｓｔｈｅｒｅｆｉｎｅｍentofbrakestructureisrequiredfOrbrakesquealreduction，therefinementofpadmaterialsisalsorequiredfOrbrakeeffectivenessandbrakesqueaIreduction・ItiswelIknownthatfrictionfiIm，ｗｈｉｃｈｉｓｃｏｍｐｏｓｅｄｏｆｐｏｌｙｍｅｒｓｌｉｋｅｐhenolfOrmaldehyderesinandsoon，innuencesfOrfrictioncoefficient・TherefOreitisexpectedthattherefinement

ofpoIymersinpadmaterialsenablehigherbrakeeffectivenessandlessbrakesqueaLlnthispaper，MoIecuIarDynamicsisappliedfOrthefrictionfOrCevariationofpolymersinpadmateriaIs・TheMDsimuIationresultssuggestthereductionmethodoffrictionfOrcevariationofpoIymers・TherefinementofpadmateriaIsisshownherebasedontheMDsimuIationresuIts，whichisassuredbyexperiments・ThispapershowsthepossibiIityoffrictionmaterialsdesignwithhigherperfOnnanceandIessbrakesqueaL

IＮＦＬＵＥＮＣＥＳＯＦＦＲＩＣＴＩＯＮＳＵＲＦＡＣＥ

Padmaterialsarecomposedofmetalfiberprganicfiber，

inorganicfiber，barite，otheradditives，graphite，phenolfOnnaldehyderesinbinderandorganicfiber[７１TablelshowsthetypicalfOrmuIationoffrictionmaterials．

TblbleLTypicalFbmnllationofFtictiomlVhtaials

（四ｍ） ＠ｍ） ‐・氏ﾛ亡(℃篝

IＮＴＲＯＤＵＣＴＩＯＮ

Recently，higherbrakeperfOrmanceincludingbrakeeffectivenessisrequiredfOrvehiclesafetyAtthesametime,brakesqueaIreductionisaIsorequiredfOrcomfOrt

ItisweIIknownthatpadmaterialsofhigherfrictioncoefficientsometimescausebrakesquealgeneration、Brakenoisereductiontechnologydevelopment［ncomestobemoreimportant，becausebrakesqueaIismuchinfIuencedbyfrictioncoefmcientofpadmaterialswhichisshowninreferences[2]ａｎｄ[３１Brakesquealis

＊dBcdTpodUm

Figurelshowsthefrictionsurfacebetweenpadanddisc・FrictionfOrcedependsontheabrasiveandadhesivefrictionmechanisｍｓＢｒａｋｅｄｉｓｃｉｓｃｏｍｐｏｓｅｄ

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model、ＡｒｅａｌｐｏＩｙｍｅｒｉｓａｓｓｕｍｅｄｂａｓｅｄｏｎｔｈemodelshowninreference[101Ａ､ymeasurablequantityQwithadimension［Q］ｓｐｅｃｉｆｉｅｄｉｎＳ１ｕｎｉｔｓｋｇｍａｎｄｓ，ismadedimensionlessbyareferencequantityQrefinequation(1)for[qinequation(2)．

ofcastiron，Throughoutbrakeburnish，friCtionfilmsincIUdingphenolfOrmaldehyderesinaretransferredfrombrakepadstodiscsurfaces，1tiswelIknownthatfrictionCoefficient〃isinfluencedbyfrictionfiImsshoｗｎｉｎＦｉｇｕｒｅ２,whichisshowninreferences[8]ａｎｄ[g1ThefrictionfOrcevariaｔｉｏｎｗｉｌｌｂｅａｂｌｅｔｏｒｅｄｕｃｅｗｉｔｈｔｈｅ

ｒefinementofpolymerslikephenolfOrmaIdehyderesin、Inthispaper,thehigherfrictioncoefficientpadmateriaIisappliedfOrthisexperiment，whichincIudeIow-steelfiberand0.1％SiCabrasive，ThehigherstiffnessandlessdampingpadmateIPialisappIiedfOrthisexperiment，whichisremovedofcashewdusts・Thebinderofpad

materiaIsisreplacedofphenoIfOrmaldehyderesintootherpoIymers．

ｍα+β/2rOβ+γごγ/2

kgαｍβSγ

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(1)

(2)

(3)一一一一一一

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ThepolymerchainlengthfOrIinearity，thepersistenceIengthIpdetenninedbythechemicalcharacteristics，isgivenbyequation(4)．ThepolymerscometogetentangledfＯｒｌｏｎｇｅｒｔｈａｎＩｐＯｎｔｈｅｏｔｈｅｒｈａｎｄ，theequationlp＝Orepresentsnobendingstiffness．

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(4)1ｐ＝ａに｡｡＋１）／２

whereａ：UnitIengthshowninFigure3[10］Ｃ､｡：FIoIPy，scoefficient■■■

FigureLFrictionSurfaces Table2showstheQreferencevaIuesofPoly-Tetra-

F1uoro-EthylenePTFEThereferencemassiscaIculatedbytheequationm＝ｍｂ(1p/lp*)／(Avogadroconstant)．UnitmassstandardpolymerFENEmodelisshowninTabIe4whichisderivedfromPTFEreferencevalues・ThereferencevaIuealength，energyandsoonarecalculatedbytheequationsshowninTable3．

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caIcuIationresultThedynamicbehaviorofmonomerispredictedbytheiterationofcalculation、ThefrictioncoefficientMsadimensionlessquantitywhichwon'tbe

infIuencedbyintermoIecularchemistry，TherefOreonepoIymerisassumedbymuItibeadsspnngmodelwithNcbeadsinthiscaIculatioｎｗｈｅｎＦＥＮＥｍｏｄｅＩｈａｓＮｃ=１００

beads、Figure5showstheeffectofagingfOreasyunderstandingWhentheactuaIcontactareaisvariedsoquickIy，frictionfOrceisaIsovariedsoquickIyAccordingIy,frictionfOrcevariationisinfluencedbyagingtimecoefficientDandreIaxationtimecoefficientて．

FrictionfOrCevariationwillbereducedbythe

refinementsofparametersDandて．Figure6showsthe

poIymermodelundershearfOrce・ｌｔｗｉＩｌｂｅａｂｌｅｔｏｃｏｎｓｉｄｅｒｔｈｅｒｅｄuctionofstressconcentrationbytherefinementofpoIymeranditscharacteristics・

理ingｐ『Bventaging

ThereferencevaluescanbecalcuIatedbyequation(1)．Thenthestressofnormaldirectionandshearstressin

frictionsurfacecanbecalculatedinequations(1),(2)and(3).Frictioncoefficientisgivenbytheratioofnormalandshearstresses．

ＤＹＮＡＭＩＣＢＥＨＡＶＩＯＲＯＦＰＯＬＹＭＥＲＳ

Equation(5)givesthemotionofmassmofbead,whichisinfIuencedbythepotentialUbondcomposedofLeonard-JonespotentialULJandFENEmodelpotentialUFENE-cshowninFigure4、BasedontheMoIecular

l1II1i薦iillii肇鵬蝋舅篭騨驚equation(5)representsviscous-elasticcharacteristicsofpoIymers．AIIentriesfOrreaIpoIymershavebeenestimatedfromthereference[11LThefOrcerepresentsthevariatio、ｆｒｏｍinitialvalueFintthroughoutmaxvalueFmaxtothefinaIstablevaIue．

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ThefrictionfOrcevariationbecomｅｓｍａＩＩｅｒｉｎｔｈｅ

ｐｏＩｙｍｅｒｗｉｔｈｓｔｒａｉｇhtchainstypestructurelikePoIy‐Amid-1midesPAIthanthepoIymerwith3-DimensionaIchainstypestructurelikePhenolfOrmaldehyderesin、lncaseofthePhenolfOrmaldehyderesin，doubIebondispresentedbythechemicalstructurethatgiveshigherfrictioncoefficientanditsvariations、ItspoIymerchainsstructurecanstoreamountofpotentialenergyandits

ThespeedofvariationisdeterminedbyagingtimecoefficientDandrelaxationtimecoefficientて．Thenthe

frictionfOrcevariationcanbecalculated・Nextstepofthedynamicbehaviorofmonomeriscalculatedbythelast

2008年10月７日９時10分1158618

Equation(7)isgivenbytheratiobetweenviscousshearfOrceandpolymerdiffusionfOrceWhenthediffUsionconstantDisverysmallthroughinterfacebetweendiscandpad,Equation(7)hasthevalueclosetoconstant．

poIymerchainsstructuresuddenIyreleaseitsenergyafteryieIdstress、ThengreaterlocalvariationoftheshearstressandthenormaIstresscausethegreater

variationoffrictioncoefficient[141

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persistencelengthNbids-lp＝19.3/4.9iscaIculated．

Thefrictioncanbeunderstoodasaprocessoftransfer

oftheenergyfromtranslationintonormalmotionofatoms・Frictioncoefficient科dependsontheequations

(6)，(7)ａｎｄ(8)showninreferences[14][15lTheseequationsarederivedfromeachconsiderationofrelationshipbetweenmacroscopicandmicroscopicviewpoints・Figure8showsthepolymermodellocatedwiththeangIesaandβtofrictionsurface・TheangIeagivesthedistancedo・Ｈｅｒｅα＝βisassumedfOrthedependenceonsurfacedensitMbeadsize,andpolymerthicknessinthismodeI，ConstantAisintroducedto

includethefactthatnon-zerofrictionexists,alsowhen

surfacedensityislargeandbeadsareverysmalLEquation(6)isgivenbytheangleainpolymerfrictionsurfaceandgeometricfactorｓｒbid，ｄｓｕｍｄｏａｎｄβｏｆ

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』i三≦二京FぐNext，caIculationresultsoffrictioncoefficientbasedontheequations(8)ａｒｅshowninFigure9andFigurelOParameterstudywasmadeinNbids-lp=４andkFENE=30．FENEspringrigidityconstantkFENE=３０isassumedbythemediumvalueofthegeneralrangeofkFENE=５－６０．Nbids-lp=４representsFENEmoｄｅｌｏｆＰＴＦＥ，whichrepresentthestandardsizefOrmodelingPoIymerdenSityNchainiSgiVenbyNchain＝８/rmon，WheremOnOmerthicknessmeasureｄｄａｔａｄｉｖｉｄｅｄｂｙＦＥＮＥＩｅｎｇｔｈｒｍｏｎ＝

5/4.9．Figure9showsthefrictionCoefficient似infIuencedbypolymerdensityNchaｉｎａｎｄＮｕｍｂｅｒｏｆＦＥＮＥＰｏ１ｙｍｅｒｆＯｒｐｅｒsistencelengthNbids-lplnshorterNbids-Ip，メノbecomeunstablewiththevariationof

polymerdensityNchain、InIongerNbids-Ip，似becomestablefOrthevariationofpolymerdensityNchain・Figure9

showstheregionsuitablefOrhigherfrictioncoefficientluandreducingitsvariatiomwhichincludesPoIy-Amid-lmidesPAl，Poly-1midesP1andPoly-EtherEther-KetonePEEKFigu｢elOshowsthatthefrictionCoefficient似isinfluencedbypolymerdensityN-chainandFENEspringrigidityconstantkFENE，InlesskFENE，ノLLbecomeunstabIewiththevariationofpo1ymerdensityNchain・lngreater

kFENE，lLLbecomestabIewiththevariationofpoIyme「

densityNchain、FigurelOshowstheregionsuitableforhigherfrictioncoefficient」uandreducingitsvariation，whichincludesPALThisregionprovidesthereductionof

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2008年10月７日９時10分1158618

frictioncoefficient似variationinhighertemperatureoffrictionsurface．． 一雨

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Thevariationoffrictioncoefficient似isreducedbythe

repIacementofthe3-DimensionalchainstypestructureIikePhenoIfOrmaldehyderesintotheotherpoIymersWithstraightchainstypestructureIikePAl､PIandPEEKTheseconSiderationsbasedonthecaIculationresults

showｎｉｎＦｉｇｕｒｅ９ａｎｄＦigurelOwereexaminedbysomeexperimentsoftestpeacesandfuIIsizediscbrake．

ＮｕｍｂｅｒｏｆＣｈａｉｎｓＮ‐chain

FigurelOFrictionCoefficientLLinfluencedbyKFENEandN-bidsFRIＣＴＩＯＮＣＯＥＦＦｌＣＩＥＮＴＯＦＴＥＳＴＰｌＥＣＥＳ

Figurel2showsthefrictioncoefficientmeasurementoftestpeaces[161ThisequipmentisfOrの50×t5discin

castiron，padmateriallO×１０mmpolymersoractuaIbrakepadmaterialsThetestpeaceispushedagainstthediscbyaircyIindercontroIledbyloadcelI．

Basedontheseconsiderations，thehigherandstabIe

frictionCoefficient/Ｌ「equiresthreecharacteristics，

polymerchainsdensityNchain＞６，NumberofFENEPolymerfOrpersistenceIengthNbids-lp＞６，FENEspringrigidityconstantskFEＮＥ＞５０．

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Thedynamicinstabilitytheory[5]describesthatflutteriscausedbydynamicunstablestructureofitsvibrationsystemanditssmalldisturbance､Thevariationoffrictioncoefficientuinpolymerwasstudied,Theconsideration

ofbrakesquealmechanismisshowninFigurell、Thevariationoffrictioncoefficient〃iscausedbyagingof

poIymers,whichisexplainedinFigure5・FrictionfOrcevariationbetweenpadanddisccausesthebendingmomentvariationofdiscshowninFigure11．Whenitsvibrationmodeisdynamicu､stable,BrakesquealwillbecausedbynuttermechanismlikecoupledvibrationofaircraftwingsBasedontheseconsiderations,thehigherandstablefrictionCoefficient似isprovidedbythe

suitablepoIymersintherequiredregionsinFigｕｒｅ９ａｎｄＦｉｇｕｒｅｌＯ・ThepolymersaresuitablefOrthepadmaterialsinhigherfrictioncoefficientandlessfrictionfOrCevariationfOrreducingbrakesqueaI．

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2008年10月７日９時10分1158618

TＥＳＴＰＩＥＣＥＳＯＦＰＲＯＴＯＴＹＰＥＭＡＴＥＲＩＡＬＳFrictionfOrceismeasuredbystraingages、ThenthefrictioncoefficientiscaIcuIatedbyfrictionfOrce，normalIoadanditsgeometry・Burnishwasdoneundertheconditions，ｎｏｒｍａｌｌｏａｄ200Nvelocitylm/s，

temperature75℃ｏｒ150℃andlhourAfterburnish,thefrictioncoefficientwasmeasuredunderthecondition，

ｎｏｒｍａｌＩｏａｄｌＯＯＮｏｒ２００Ｎ，velocitylm/s→Ｏ→１ｍ/s，

temperature75℃ｏｒ150℃．

ThehigherfrictioncoefficientpadmaterialwasappliedfOrthisexperiment，whichincludelow-steelfibberanｄ0.1％SiCabrasiveThehigherstiffnessandlessdampingfactorpadmaterialwasappliedfOrthisexperiment,whichwasremovedofcashewdusts、AndthebinderofpadmaterialswasrepIacedofPhenolfOrmaIdehyderesintoPALFigurel4showsthefrictioncoefficientinpadtemperaturel５０℃influencedbysIidingvelocityinConventionaIpadmaterialsusingPhenolfOrmaldehyderesinbinderandprototypepadmateriaIsusingPA1binder．

ＴＥＳＴＰＩＥＣＥＳＯＦＰＯＬＹＭＥＲＳ

ItispredictedbycalcuIationresultshowninFigure9thatthefrictio、CoefficientメＬｉｓｓｔａｂｌｅｉｎＰＡＩ，ＰｌａｎｄＰＥＥＫ、

Figurel3showstheexperimentalresuIts・ThesegraphsshowthefrictioncoefficientuinfluencedbysIiding

veIocityinPhenolfbrmaIdehyderesin，ＰＡｌａｎｄＰＥＥＫＴｈｅｌｅｆｔｇｒａｐｈｓａｒｅｆＯｒthepadtemperature75℃、Andtherightgraphsarefbrthepadtemperaturel5０℃･ltisshownthatthefrictioncoefficientluofPhenol

fOrmaIdehyderesinisunstable,especiaIIyin１５０℃・Ontheotherhand,thefrictioncoefficient〃ｏｆＰＡ１ｉｓｓｔａｂｌｅ・

Itisshownthatthefrictioncoefficｉｅｎｔ－ｌｕｏｆＰＥＥＫｉｓ

stableｉｎ７５℃,butunstabIein１５０℃．ＦｉｇｕｒｅｌＯｓｈｏｗｓｔｈｅｉｎｆｌｕｅｎｃｅｏｆＦＥＮEspringrigidityconstantkFENE，It

representsthatthefrictionCoefficient似isinfluencedbyFENEspringrigidityconstantkFENE，whichrepresentsthecapacityfOrtheinfluenceoffrictionsurfacetemperature・ThefrictioncoefficientlLLisstableinhigherFENEspringrigidityconstantkFENE．

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Figurel4FrictionCoefficientsofPrototypeMaterials

Theaverageαｉｓａｌｍｏｓｔｓａｍｅ，Thenegativeslopeoffrictioncoefficientversusslidingvelocityisalittlebitdifferent・ｌｔｗｉｌｌｂｅａｂＩｅｔｏｐｒｅｄｉｃｔｂｒａｋｅｅｆｆectiveness・ButitwillbedifficulttopredictbrakesquealgenerationbasedontheｄａｔａｉｎＦｉｇｕｒｅｌ４１ｔｉｓｐｏｓｓｉｂｌｅｔｏｐｒedictbrakesquealgenerationbasedonthedatainFigurel3．

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BrakesquealevaluationtestsweredonebyfullsizefIoatingcaliperfrontdiscbrakesystemfOrpassenge｢car・Thisdiscbrakehasの５７pistonincylinderoffloating

typecaliperandの２５５×２２ｍｍ・ventilatedtypebrakediscmadeofcastiron,Anti-squealshimswereremovedfOrduplicationofbrakesquealtest・Figurel5andFigurel6showthedynamometerbrakesquealtestresults，BefOrebrakesquealtests，１０００timesbrakestopsweredonefOrbrakeburnish，whichwasconStructedofinitial

vehiclevelocity＜５０ｋｍ/h，padtemperature＜150℃，desecration＜０２９.AfterlOOOtimesbrakebumish,５００timesstopsweredonefOrbrakesqueaIevaIuationtest，whichwasconstructedofthesamekindsofbraking

condition・Figurel5showsthecomparisonoftherateofbrakesquealgeneration・TheIeftgraph，fOrtheconventionaIpadmateriaIusingPhenoIfOrmaldehyderesinbinder,showstherateofbrakesquea１８２％in500timesbrakingTherightgraph，fOrtheprototypepadmaterialusingPA1binder，showstherateofbrakesqueal40％in500timesbraking・Thefrictioncoefficientisalsomeasuredinthisbrakesquealtest､Theaveragevalueoffrictioncoefficientisalmostsame処＝0.42.You

canseetheeffectofthereplacementofPAIbinder．

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Figurel3FrictionCoefficientofPoIymerTestPeaces

2008年10月７日９時10分1158618

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itsvariationcanbeprovidedbythethreesuitabIecharacteristics，poIymerchainsdensiIyNchain＞６，ＮｕｍｂｅｒｏｆＦＥＮＥＰｏｌｙｍｅｒｆＯｒｐｅｒｓｉｓｔencelengthNbids-1p〉６，FENEspringrigidityconstantskFEＮＥ＞５０．TherefinedpadmaterialproductswilIbedevelopedafterotherrequirementsstudies，fade，wear,ａｎｄｓｏｏｎ．

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(a)Phenolfbmlaldehyde1℃sinBinder（b)PAIBinderＲＥＦＥＲＥＮＣＥＳ

Figurel5､RatioofBrakeSqueaIGeneration １．Ｍ.Nishiwaki，‘`Reviewofstudyonbrakesqueal"，

JapanSocietyofAutomobiIeEngineeringReview，１１(4),ｐ48-54(1990)．

２．Ｎ．Millner,“AnAnaIysisofDiscBrakeSqueaI，，，ＳＡＥPaper,780332(1978）

３．Ｍ.EriksonandS・Jacobsen，,，Frictionbehaviorand

squealgenerationofdiscbrakeatlowspeed，Proc・

lnstn、Mech，Engrs.，ＰａｒｔＤ，JournalofAutomobiIeEngineering,pl245-1256(2001）

４．Ｍ.Nishiwaki，“GeneralizedTheoryofBrakeNoise"，

Proc，Inst、MechEngrs.，JoumaIofAutomobileEngineering,ＶＯＬ207,PartD，pl95-202(1993)．

５．Ｖ､VBolotin，‘‘NonconservativeProbIemsofthe

TheoryofElasticStabiIity"，PergamonPress，ｐ7-9

（1963)．6.Ｇ.DLiles,，，AnaIysisofDiscBrakeSquealUsingFinite

ElementMethods，，,ＳＡＥPaper,891150(1989)．７．Ｙ・SasakiandSKusaka，”TheTransitionof

AutomotiveBrakeLiningMateriaIs"，JoumaIof

JapaneseSocietyofTriboIogists，Vol､４１，Ｎ０．４，

pl97-201(2003）８．ｓ.KRhee，Ｍ､Ｇ・JackoandH.Ｓ・Tsang，，，Theroleof

frictionfilminfrictio､，wearandnoiseofautomobile

brakes,，,SAEPaperNo900004(1990)、９．Ｎ､Odani，MKobayashiandK,Kakihara，轍Effectof

TransferredSurfaceFilｍｏｎ似BehaviorofDisc

BrakePadinHumidityEnvironment",ＳＡＥＰａｐｅｒＮｏ、

1991-01-3391(1991)．

10.Ｈ,YanagiharaandM,Kroeger,，'Polymermaterial

designmethodanddesignsystem，'，JapanPatentApplicationNumber2005-163662(2005)．

１１．ＲｏＳＰｏｒｔｅｒａｎｄＪ・Ｆ・Johnson，Ｃｈｅｍ、Rev､６６，

１(1966)；Ｊ,BrandrupandEH,Immergut（eds)，

象|酸li19；:flbookoWiloy-ln…ien･aNewYo『k'12.Ｍ.Kroeger，“SimpIemodelsfOrcomplexnon

equilibriumfluids，,,PhysicsReportsp453-551(2004）１３.WikipediathefreeencycIopedia，“Phenol

fOrmaldehyderesin",http:"enwikipediao｢g/Wiki/Phenol

l4MNishiwaki，HYanagihara，Ｙ,FUjioka，ＫＡｂｅandHIsono,`DesignmethodoffrictionmateriaＩｓｗｉｔｈｎｏｎｏｉｓｅ，，,Patentpending

１５．Ｊ・Ｋｉｍ,“Atomic-scaIeoriginsoffrictio､''’1angmuir,１２，ｐ4564-4566(1996)．

16.Ｙ・Nagasawa，Ｋ・Yoshida，MHashimotoand

MNishiwaki，‘`Frictiontestpiecetester，Japan，PatentApplicationNumber2004-12172(2004)．

Figurel6showsthecomparisonofthebrakesqueaIfrequencyandsoundpressureleveLWhenbrakesquealoccur,itspeakofsoundpressureandsqueaIfrequencyanaIyzedbyFFTwaspIottedinFigurelaTheleftgraphisfOrtheconventionalpadmateriaLandtherightgraphisfOrtheprototypepadmateriaLThesoundpressureIevelisreduceｄ２０ｄＢｌｏｗｅｒ・ＴｈｅｎbrakesquealwasaImostdisappeare｡．

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Figurel6・BrakeSquealEvaluationTests

Thisreplacementofpolymerprovidesthesamelevelbrakeeffectivenessandtheremarkablebrakesquealreduction・BasedontheconsiderationofpolymerfrictionfOrcevariation，prototypepadmaterialwasdesignedfOrhigherfrictioncoefficientandlessbrakesqueal．

ＣｏＮＣＬＵＤＩＮＧＲＥＭＡＲＫＳ

(1)BrakeSquealiscausedbydynamicinstabiIity,whichdependsonitsdynamicunstabIestructureofvibrationsystemanditsdisturbanceoffrictionfOrcevariation・AssameasbrakestructurerefinementfOr

dynamicstabilityisrequiredfOrnobrakesqueal,ｔｈｅｒｅductionoffrictionfOrcevariationisalsorequired．

(2)ThispapershowsthepossibilityofhigherbrakeperfOrmancewithlessbrakesquealinpadmaterials

design．Thehigherfrictioncoefficient似andthe

reductionofitsvariationcanbeprovidedbytherepIacementofstraightchaintypemoleculestructurepolymers．

2008年10月７日９時10分1158618

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