第4章摩擦磨损及润滑概述.pptx

第4章摩擦磨损及润滑概述.pptx

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4-0Overview4-1Friction4-2Wear4-3Lubricant、additiveandlubricationmethods4-4Introductionoffluidlubricationprinciple,中南大学,Chapter4,Theoverviewoffriction、wearandlubrication,4-0Overview,中南大学,Tribology-studyfriction、wearandlubricationoftwosurfacesmovingrelatively。

Itisanedgeprinciple。

frictionTwosurfacesmovingrelativelyhindereachother；wear-materialofobjectsurfacelosesortransmitbecauseoffriction；lubricationthemethodreducingfrictionandwear。

About1/31/2energyintheworldisconsumedinfriction。

Themajorityofmachineelementsarerejectedandreplacedbecauseofexcessivewear。

ReducefrictionReducewear,saveenergy；lowerthemaintenancecost。

1、principleoffriction“mechanicaltheory”thefrictionishindranceactionofconvexo-concavesurface；“moleculartheory”thefrictionistheattractiveforceofmoleculeofmaterialsurface；“mechanical-moleculartheory”bothaction。

2、typesoffrictionInternalfriction：

thephenomenonofhindranceofrelativemovementofmolecule。

Externalfriction：

thephenomenonofhindranceofrelativemovementofsurface。

Staticfriction：

frictionhavingrelativemomenttendency。

Dynamicfriction：

frictionhavingrelativemoment。

Slidingfriction：

ThemovementbetweentwosurfacesisrelativeslidinRollingfriction：

Themovementbetweentwosurfacesisrelativerollin,中南大学,4-1Friction,Nodryfriction！

中南大学,3、Slidingfriction

（1）DryfrictionThesurfacesoftwoelementscontactdirectly，manycold-scoringpointscausedbyhighpressofpartareamaybeshearedwhenmoving。

consumptionofpowerweartemperature,damagethesleeve

（2）BoundaryfrictionThereisasheetofoilfilmbetweenthetwosurfacesofpair.Thethicknessofoilfilmislessthen1mTheoilfilmcantseparatecompletelythetwosurfacesof,f0.10.3,v,metalbody。

（3）FluidfrictionThesurfaceofpairhaveasheetofpressoilfilmthatcanseparatethesurfaceoftwometalbody。

Itisanidealcondition。

f0.0010.01,v,v,v,中南大学,f,o,4.MixturefrictionThefrictionconditionoftwosurfacesisbetweenboundaryfrictionandmixturefriction。

Thefrictioncoefficientofmixturefrictionismorelessthanthatofboundaryfriction。

Boundary,friction,Mixturefriction,Fluidfriction,Frictionfeaturecurven/p,-,Boundaryfrictionandmixturefrictionareverydifficulttodifferinengineeringandalwayscallednonfull-filmfriction。

在n/一p般机-器-b中e，a处ri于n后g三p种a情r情ra况m的e混te合r状态。

kinematicalviscosity，p-pressure，n-rotatingspeedrecentdevelopmentofTribology：

MillimicronTribology,reach：

f0.001-super-lubricationfrictioncondition。

Lifeofmachine,中南大学,Wearcurve,Wearvolume,timesharpwearperiod,stablewearperiod-,4-2Wear,Theprocessofwear：

run-inwearperiod-Itresultsfromtheroughnessofprocessingsurface。

stablewearperiod-Thewearrun-inwearperiod,speedofelementissteadyandslow。

wearthematerialofelementsurfacedisappearedorremovedbecauseoffriction。

effectlowertheefficientandreliabilityofmachine。

sharpwearperiod-thegapofpairincreaseandcausethevibrationofmachine。

Theelementmayberejected。

Whiledesigningthemachine,wewishtherun-inwearperiodwereshorten，thestablewearperiodwereprolongedandsharpwearperiodwereputoff。

typesofwear：

中南大学,AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,accordingtotheweartheory,accordingtotheappearanceofwearsurface,PittingwearScorchingwearScoringwear,weartheory：

中南大学,AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,AbrasivewearItisalsocalledwear.Thedustintheairandmetalparticleweartheelementsurfaceandproducemanyscores。

weartheory：

中南大学,AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,AdhesivewearItisalsocalledscorching。

Thefrictionsurfaceinteracteachotherandthematerialisremovedfromonemetalsurfacetoanotherbecauseof“coldwelding”causedbyinstantriseoftemperatureandpressure。

weartheory：

中南大学,FatigurewearItisalsocalledpitting。

Theprocessofpitting：

earlyfatigurecrackextendparticledropandformpit。

AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,weartheory：

中南大学,ErosionwearThehardparticlesinflowfluidorgaspoundtheelementsurface。

Example:

airhighpressurepump。

近年来，由于燃气涡轮机的叶片、火箭发动机的尾喷管这样一些部位的破坏，才引起人们对这种磨损形式的特别注意,AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,weartheory：

中南大学,CorrosionwearThefrictionpairsiscorrodedandmoverelativelyinthechemicalandelectrochemicalenvironment。

AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,weartheory：

中南大学,FretwearItisacompoundwearformedbyalltheabove-mentionedtheorieswhenthefrictionpairshaveslightshock。

example：

interferencefitjointofaxialandhole、workingsurfaceofrivet。

AbrasivewearAdhesivewearFatigurewearErosionwearCorrosionwearFretwear,Typesofwear,types,中南大学,Liquidlubricant-lubricatingoilSemi-solidlubricant-lubricatinggreaseSolidlubricant,1）Lubricatingoil,Themineraloiliswidelyusedbecauseitissufficient、cheapandstable。

types,1、lubricantfunction：

tolowerpowerconsumption、todecreasewear、tocooltheelement、toabsorbvibration、toberustproofandsoon。

Gaslubrication-air,Organicoil-animaloil、vegetableoilMineraloil-petroleumproductsChemicalsynthesisoil,4-3Lubricant、additiveandlubricationmethod,A,中南大学,粘度表征液体流动的内摩擦特性。

A、B两板之间充满了液体，B板静止，A板水,作用，A板表面的液体速度为v，而B板表面的,0,液体速度为。

两板之间的速度呈线性分布。

Thefrictionshearstressbetweenfluidlayers：

dudy,-shearstressisproportionaltovelocitygradient。

-Dynamicviscosity,unit：

Ns/m2（Pas）iscalledpoise。

orcentipoise：

1P=1dyns/cm2,Experimentresult：

=,o,x,y,ydy,du,分析位置y处薄层的受力,B,viscosity-itisanimportantindex。

Thehighertheviscosityis，在轴th承e中t，h润ic滑k油e最r最r重o重oi要l的is物。

理参数,types,是粘度，它是选择润滑油的主要依据D。

ynamicviscosity平移动速度为v。

由于液体与金属表面的吸附,KKiinneemmaattiiccaallvviissccoossiittyy,Conditionalviscosity,

（1）Dynamicviscosity,-Newtonfluidtheory,1poise=100centipoise,=,-7,180,steamturbineandgenerator,GB11120-89中南大学,L-TSA46,41.450.6,unit：

m2/s,iscalledstokeSt：

cm2/s,orcentistokecSt：

1St=100cSt,

（2）KinematicalviscosityKinematicalviscosity（convenient）:

list4-1,Name,LosssystemoilGB443-89,Lubricationandcoolingofhighspeedandlightloadmachineandprecisionmachinetools。

Lubricantofcommonmachinetools。

Lubricationofslidebearing、geardrive、wormdrive.,Lubricationofheavymachinetoolsandminemachine。

Lubricationofslidebearingof,SteamturbineoilL-TSA32,28.835.2,maincharacteristicsoflubricationoilMainuse,（3）ConditionalviscosityWeuseviscosimetertomeasurethetimetheoilpassthroughthefixedholeundergivenconditiontodeterminetheviscosity。

中南大学,Commonuse：

恩氏度（Et）-Chinese,赛氏通用秒（SUS）-American雷氏秒（R）-English,TherelationsbetweenKinematicalviscosityandConditionalviscosity：

cSt,t,t,E,8.64,当1.35Et3.2时，Vt8.0E,cSt,t,t,E,4.0,当Et3.2时，Vt7.6E,当Et16.2时，Vt7.14EtcStThelubricanttrademarkrelatestothekinematicalviscosity。

ThekinematicalviscosityofL-AN10lubricantat40is10cSt。

Characteristicsoflubricant：

（1）viscosity-temperature,中南大学,Temperaturet,viscosity-temperaturediagram,0.07,0.06,0.05,0.04,0.03,0.02,0.01,30405060708090,0.08,L-TSA32,L-TSA32,L-TSA32,L-TSA32,Pressurepp100Mpahaslittlechange.Theviscosityoflubricantnotonlyinfluencetheobstructionoffrictionpairbutalsoplayanimportantpartinformingtheoilfilm。

Choiceprinciple：

Temperaturetloadload、speed.,oilinessAsheetofboundaryoilfilmisformedandadherestothemetalsurfacebytheabsorptionaction.Thiscanlowerthefrictionandwear。

polarpressureWhenthepolarcompoundwhichcontainssulphurandphosphorusisputintothelubricatingoil,thepolarmoleculewillimprovetheboundarylubricity。

flashpointWhenthelubricatingoilisheated,theoilsteammayflashatcertaintemperature。

Theworkingtemperatureofmachineshouldlower3040thantheflashpoint。

pourpointWhenthetemperatureoflubricatingoilislowered,theoilcantflowfreelyatcertaintemperature。

Thiswillinfluencethemachinetostart。

中南大学,lubricatinggreaseAlubricatinggreaseisasolidorsemisolidlubricantconsistingofathickeningagentinaliquidlubricant.Soapsofcalcium、sodiumandaluminumarethemajorthickeningagent。

Advantage：

lessfrequentlubricantapplicationisnecessary;

（2）lesssensitivetothetemperatureandspeed。

Disadvantage：

Themachineefficiencyislow。

Calciumgrease-widelyusedinengineering,中南大学,types,SodagreaseAluminumgrease,polyvinyl,中南大学,fluorideresin,molybdenum,-lowfrictionalcoefficient，usedinwide-range,disulfide（MoS2）oftemperature（-60300），Butthe,-lowfrictionalcoefficient,beinghalfofthatofgraphite,performancereduceassoonasmeetingwater.appliancesituation：

usedinthesituationinwhichlubricantoilcannotwork，suchashightemperature、lowspeedandheavyload、thesituationinwhichcleanenvironmentisrequired.themethodsofuse：

（1）.mixedwithoil；

（2）.coated、sinteredonfrictionsurfacetoformcoveringfilm；（3）.mixedwithmetalorplasticpowder,thensinteredtoformbearing,其应用日渐广泛,3）solidlubricantanditschoicecharacteristics：

solidfilmisformedonslidesurfacegraphite-steadyperformance、whent350begintooxidize，canworkinwater.,Oilinessagent,中南大学,types,2、additive,F,irir,tctc,io,non,c,eoeo,f,cici,eiei,tntn,f,OilcontainingpolaragentandfattySofttemperaturet/,Oilcontainingfattyacid,Oilcontainingpolaragent,Additive-inordertoimprovethepropertyoflubricant,wealwaysaddsomematerials。

function-limitchemicalchange、improveoiliness、prolonguselifeandsoon。

Nopolaroil,Polaragent,Antifoamagent,Oxidationinhibitor,Pourdepressant,Viscosity-indeximprover,3、lubricationmethodsThelubricatingoilisusedveryuniversallyinengineering。

中南大学,manuallubrication；,Lowspeedd