飞机轮胎介绍.ppt

,AircraftSystemAircraftTires,ClassificationofTiresTypeSizePlyrating(层数）Tubeortubeless,ClassificationofTiresTypetireCharacteristic:Lowpressure,piston-poweraircraft.Constructioncharacter:Thesectionwidthisrelativelywideinrelationtothebeaddiameter.DesignatingMethod:Sectionwidthandrimdiameter9.50-16tire:thesectionwidthis9.5inches,therimdiameteris16inches.,ClassificationofTiresTypetireCharacteristic:Extra-highpressure,jetaircraft.Constructioncharacter:Plyratingfrom4to38.DesignatingMethod:Outsidediameterandsectionwidth3813tire:Theoutsidediameteris38inches,thesectionwidthis13inches.,ClassificationofTiresTypetireCharacteristic:Jetaircraft，highload-carryingability,Plyrating:4to38Constructioncharacter:Lowprofile.DesignatingMethod:Outsidediameter,sectionwidthandrimdiameter.3011.50-14.5tire:Theoutsidediameteris30inches,Thesectionwidthis11.50inches,Therimdiameteris14.5inches.,ClassificationofTiresDesignatingMethod:ATypeVIIIorthree-partnomenclaturetireisidentifiedby3parameters:overalldiameter,sectionwidth,andrimdiameter.Theyarearrangedinthatorderwiththefirsttwoseparatedbyan“X”andthesecondtwoseparatedbya“.”Forexample:18X4.2510designatesatirethatis18inchesindiameterwitha4.25-inchsectionwidthtobemountedona10-inchwheelrim.,BiasorRadialTireAnothermeansofclassifyinganaircrafttireisbythedirectionofthepliesusedinconstructionofthetire,eitherbiasorradial.Traditionalaircrafttiresarebiasplytires.Thepliesarewrappedtoformthetireandgiveitstrength.Theangleofthepliesinrelationtothedirectionofrotationofthetirevariesbetween30and60.,BiasorRadialTireInthismanner,theplieshavethebiasofthefabricfromwhichtheyareconstructedfacingthedirectionofrotationandacrossthetire.Hence,theyarecalledbiastires.Theresultisflexibilityasthesidewallcanflexwiththefabricplieslaidonthebias.,PlyRatingItisjustastrengthindexbutinthepast.Tiresaregivenaplyrating,ratherthanspecifyingtheactualnumberoflayersoffabricmaterialusedinthecarcass.Theplyratingofatirerelatestoitsmaximumstaticloadanditsinflationpressure.,TubeorTubelessTiresTubelesstires:one-tenthofaninchthickinnerliner“TUBELESS”onthesidewallTubetires:noinnerliner,smootherinsidesurface.no“identification”onthesidewall,ConstructionofTireAutomobileandtrucktires1.differentspecificationsfromthoseusedforaircrafttires.2.tooperateforlongperiodsoftime.3.arelativelylargebutsteadyloadatreasonablyhighrotationalspeeds4.arelativelysmallamountofdeflection（变形）.CarTires:acontinualdeflectionofonlyabout12to14%.,ConstructionofTireAirplanetires1.strongenoughtoabsorbthetremendousloadsexertedonthemattouchdown.2.theymustoperateatveryhighspeeds.3.thegroundrolldurationislimited.4.adeflectionofbetween32and35%,morethantwicethatallowedforautomobiletires,BEAD（胎缘）Thebeadsaremadeofbundlesofhigh-strengthcarbon-steelwire,withone,two,orthreeofthesebundlesusedineachsideofthetire.Themostimportantpartofatire.Toprovidesafirmmountingsurfaceforthetireonthewheel.Allofthegroundforcesonthetireterminateinthebead.Figure9-71,RubberApexStrips(橡胶填充层)Definition:Topackandstreamlinetheroundbeadbundles,sothefabricwillfitsmoothlyaroundthemwithnovoids.,Flippers（隔离层）Definition:Layersofrubberandfabricenclosethebeadbundlestoinsulatethecarcasspliesfromthebeadwires.Function:Becausethegreatestamountofheatinthetireisconcentratedinthebeadarea,thisinsulationincreasesthedurabilityofthetire.,CARCASSandTURN-UPS（胎体和重叠层）layersorpliesofrubber-coatednylon-cordfabric.thecordsofthefabricatanangleofapproximately450tothelengthofthestripthestripsextendcompletelyacrossthetireandlapbackoverthebeadstoformtheplyturn-ups.eachsuccessiveplyofthefabricisplacedinsuchawaythatthecordscrosseachotheratapproximately900tobalancethestrengthofthecarcass.,CHAFERS（胎缘包覆层）Definition:Layersoffabricandrubberwraparoundtheedgesofthecarcasspliesandenclosetheentirebeadarea.Function:Theyprovidechaferesistancebetweenthebeadandthewheel.,UNDERTREAD（底胎面）Definition:Apliesofspeciallycompoundedrubberplacedoverthecarcass.Function:Toprovidegoodadhesionbetweenthetreadandthecarcass.,TREADREINFORCINGLAYER（胎面加强层）Definition:Oneormorepliesofnylonfabricstrengthensthetread.Function:1.toopposesthecentrifugalforcesthattrytopullthetreadfromthecarcassduringhigh-speedoperation.,TREADREINFORCINGLAYER（胎面加强层）2.Italsostabilizesthetreadonthecordbodyandpreventsitfromsquirming（蠕动)ormoving.3.Thisreinforcementdoesnotenterintotheplyratingofthetire,butitisusedasaguidefortheretreaderwhenbuffingthetiretoremovethetread.,TUBELESSTIRELINER（无内胎轮胎衬层）Definition:Aspecialcompoundofrubberthatislesspermeablethantherubberusedintherestofthetire.athincoatingofrubberovertheinnerplycordsprotectsthelinerfromchafing.Function:Thelineractsasacontainerfortheairandminimizestheamountofairthatseepsoutthroughthecasingplies.,TREAD（胎面）Definition:Thewearingsurfaceontheoutercircumferenceofthetire.Characteristic:1.Itismadeofspeciallycompoundedrubber.2.Apatternofgroovesmoldedintoitssurfacetogivethetiretherequiredtraction(附着力）accordingtothetypeofrunwaysurfacetheaircraftwillencounter.,TREADPATTERNSPlainTreadPlain,orsmooth,treadisusedonsomehelicopterandonverylightairplanes.Allweathertread1.All-weathertreadshavearibtreadinthecenteranddiamondsmoldedintotheshoulders2.Thediamond-shapedtreadpatterniseffectiveforaircraftoperatingongrassorhard-packeddirt,andtheribtreadinthecentergivesgoodtractiononhardsurfacedrunways【Figure9-72,RibTreadTheribtreadisthemostpopulartreadpatternfoundonmodernaircrafttoday.1.useonhard-surfacedrunways.2.longtreadwearlife3.goodtraction4.exceptionallygooddirectionalstability.Figure9-73Thewidthanddepthofthegrooves,theirplacementonthetreadaredeterminedbyoperatingconditionsofaircraftforwhichtheyaredesigned.,CHINE(胎脊、偏转器）Chinesordeflectorsmoldedintotheuppersidewalloftireonthenosewheel.Tiresfordualnosewheelinstallationshavechinesononesideonly,Singlenosewheelinstallationshavedualchines(deflectors)，oneoneithersideofthetireFigure9-74Function:Topreventwaterorslushfrombeingthrownupbythenosewheelandenteringtheengines，Figure9-74,SIDEWALLDefinition:ArubbercoveringthatextendsfromthetreaddowntothebeadheelFunction:Toprotectthecarcassfrominjuriessuchascutsorbruisesandfromexposuretomoistureandozone.,VENTHOLESDefinition:Ventholesinthelowersidewalltoallowtheairseepingintosidewalltoescape.Theseholesaremarkedwithpaintandmustbekeptopenwhenthetireisretreaded.Function:Whenthetirewasheated,toavoidplyseparationandthetreadtobethrownfromthetire.,TIREINSPECTIONONTHEAIRCRAFTMostinspectionontheaircraftScheduledinspectionsofthetiresThetechnicianshouldtakealookatthetiresanytimeworkisbeingdoneinthevicinityofthegear.,轮胎充气的基本要求1.如果将轮胎始终维持在正确压力，轮胎寿命会更长。2.如果用干燥的空气给轮胎充气，确保氧气含量不超过5%。3.如果轮胎压力比正确压力低5%或更低，则为轮胎充气。4.如果轮胎压力比正常压力低5%15%，给轮胎充气并在24小时后检查。5.如果轮胎压力比正常压力低1530%，拆卸并更换机轮和轮胎组件。6.如果轮胎压力比正常压力低超过30%，拆卸并更换机轮和轮胎组件。如果轮胎在压力下降后机轮转动并承担飞机重量，更换安装在轮轴对侧的机轮和轮胎组件。,HeatDamageThegreatestenemyofanaircrafttireisheat.Heatresource:1.Theheatgeneratedwithinthetireasitrollsovertheground,thesidewallsflexandcauseinternalheat2.Theheatfromexternalsourcessuchasthebrakesorhotrunwaysurfaces.,InflationPressure1.ThepressureshouldbecheckedDailyinspectionPreflightinspection2.Differencesinairpressurebetweendualmountedtiresshouldcauseconcern.Itdefeatsthepurposeofdualmountedtires3.Anypressuredifferenceshouldbecorrectedandnotedintheaircraftlogbook.Consulttheaircraftservicemanualtodeterminetheexacttirepressuretolerances.,InflationPressureInflationpressureshouldalwaysbemeasuredwhenthetireiscold.Twotothreehoursshouldelapseafteraflightorbeforethepressureismeasured.Tirepressurecheckisthemostimportantpartsofroutinepreventivemaintenance.Thepressureintheaircraftservicemanual,ratherthanthatlistedinthetiremanufacturersproductmanuals.Reason:tirepressuresvaryfromoneaircraftdesigntoanother.,InflationPressureThepressurespecifiedintheairframemanufacturersmanualisforaloadedtire,Ifservicedandinflatedofftheaircraft,theinflationpressureshouldbefourpercentlessthanthepressurespecified.(180psi,187psiintheAMM)Pressuregaugesshouldbeperiodicallycalibrated.InflationpressureofatirevarieswiththeambienttemperaturebyaboutonepercentforeveryfivedegreesFahrenheit.,InflationPressure1.Ifatireisinflatedandallowedtostabilizewithapressureof180psiinashopwherethetemperatureis70F.2.Andtheairplaneisrolledoutsidewhereitremainsovernightwithatemperatureof0F,thepressurewilldropby14%toabout155psi.3.Obviously,tirewouldthenbeseriouslyunder-inflatedandshouldbereinflatedto180psi.,InflationPressureAnairplaneistoflyintoanareawherethetemperatureismuchlowerthanthatofthedepartingpoint.Theoretically,thepressureshouldbeadjustedbeforetheairplaneleaves.1.Thetemperatureatthedepartingairportis100F.2.Theairplaneistolandattheanotherairportwherethetemperatureis40F.3.Thepressureshouldbeincreasedbeforetakeoff.,InflationPressure4.Ifthetirerequires187psi,the60Ftemperaturedropwillrequirethepressuretobe12greater,or210psi.Themaximumallowablesafe-inflationpressureinAMMcouldnotbeenexceeded.Nylontirewillstretchandincreasetheirvolumeenoughtocausepressuredropaftertheyarefirstinflated.Thepressuresshouldbeadjusted12to24hoursafterfirstinstallation.Conclusion:Every5Ftemperaturedropwillrequiretheinflationpressuretobeincreased5.,Over-inflationItcausesmorecenterlinewearonthetreadthanthatontheshoulder.Whenatireisworninthisway,ithasmuchlessresistancetoskiddingthanwhenitstreadwearsuniformly.,Over-inflation,Under-inflationItcausesoverdeflectionExcessheatwithinthetire.(45%deflection,threetimesheatbuildsupintire)Treadwornawayontheshouldersmorethaninthecenter.Tiresshowingthispatternofwearshouldbecarefullyexaminedforevidenceofhiddendamage.,Under-inflation,TREADCONDITIONBasicstrengthofatireisdeterminedbyitscarcass,atirelosesnothingofitsstrengthaslongasthetreaddoesnotweardowntothebodyplies.Itshouldberemovedforretreadingwhilethereisstillatleast1/32-inchoftreadleftatitsmostshallowpoint.,CorrectInflationPressureNormalWearThecorrectinflationpressurewillwearthetreaduniformly.Figure9-76,AbnormalWearofTireTread1.UneventreadwearCause:thelandinggearisoutofalignment.Measures:Wheelalignmentshouldbecheckedsoitconformstothespecificationsoftheaircraftservicemanual.Iftheunevenwearisslightandthelandinggearisnotadjusted,thetiresmayberemoved,carefullyinspected,andreversedsothewearwillevenout.,AbnormalWearofTireTread2TreadwearinspotsCause:malfunctioningbrakesimproperlytorquedbearingswornstrutpartslandingwithbrakesengaged.,TreadcutAtireshouldberemovedformserviceifthetreadiscutacrossmorethanone-halfofaribwidthCause:glass,rock,ormetalFigure9-80groovedrunwayFigure9-82Note:removeglass,rock,ormetalwithabluntawlorscrewdriver.,TreadburnAtireshouldberemovedformserviceifthetreadshowstheburningmarkonthecontactpointwiththerunwayorwaterontherunway.Figure9-81Cause:hydroplaning(打滑）alockedbrake,InspectionofTread1.Ifthecordbodypliesarevisible,thetirecannotberetrodden.Figure9-792.Ifthetreadreinforcementjustisshowing,thetiresarepossiblyretrodden.3.Anytimethetreadiscutmorethanhalfwayacrossarib，oranyofthecarcasspliesareexposed，thetireshouldberemovedfromserviceFigure9-80,InspectionofTread4.bitsofglass,rockormetalembeddedinthetreadshouldbecarefullyremovedwithabluntawlorasmallscrewdriver.5.Tiresshowingburnatthepointofcontactshouldberemovedfromservice.6.Operatingongroovedrunwayscancausechevron-shaped(V-shape)cutsacrosstheribsofatire.Iftheyextendacrossmorethanone-halfoftherib,thetireshouldberemovedfromservice.,InspectionofTread7.Anydamagedorsuspectareaofthetireshouldbemarkedwithalight-coloredmarkerbeforedeflatingthetire.8.Anytreaddamageshouldbecarefullyevaluatedbyalicensedretreadingagencytodeterminewhetherornotthetireisrepairable.,SidewallPurpose:Itprotectsthecarcasspliesfromdamage,eitherfrommechanicalabrasion,fromdeteriorationbychemicals，orbythesun.1.ifsmallsnags,cuts,weathercracksdontexposethecords,thetireshouldnotberemovedformaintenance.2.Checkforopenholesonthesidewall.Theventisusedtorelievetheairdiffusedintothebodypliesfromthetirecompartmentinordertoprotectthepliesfromseparation.,ProcedureofTireRemoval1.jacktheaircraftup.2.whentheweightisoff,deflatethetireusingadeflatorcap.3.removedthecoverofinflationvalve.4.removethewheel.5.clean,inspectionandrepackthebearingswithpropergrease,protectitfromdamage.,ProcedureofTireRemoval6.putthewheelonaflatsurface,thebeadseparatedfromthebeadseatareaofthewheelusingastraightpushasneartotherimaspossible.Figure9-83Caution:Nokindoftiretoolshouldbeusedtoprythebeadfromthewheel,becausethewheelcanbecomenickedorscratched-stressconcentrationsatthepointofthenickorscratchthatcouldleadtowheelfailure.,ProcedureofTireRemoval8.removethewheelbolts,thenremovethewheelhalvesfromthetire.9.forthetubelesstire,theO-ringbetweenthewheelhalvesshouldbeinspectedfordamage.,ReplacementofTire1.Abortedtake-off2.Severebrakes3.Thefusibleplughasmeltedandthetirewasdeflated.4.Ifonetireinadualinstallationfails,anotheroneshouldbereplacedatthesametime.,InspectionofInnerLinercracksbulgesorblisters（凸起）Caution:1.beadshouldnotbespreadmorethanthesectionwidthofthetire.2.forceusedtospreadthebeadsshouldnotbeconcentratedinonearea.3.improperspreadingmethodcankink（纽结）thewirebundlesandthetiremustbescrapped.,Inspectionofthemarkedarea1.inflatethetire2.cutsshouldbeopenedupenoughtocheckthedepth.3.Puncturesthatdonotexceedone-quarterinchontheoutsideofthetire,one-eighthinchontheinside,neverpuncturethetire.,InspectionofBead&AdjacentArea1.Severedamagefromtiretoolsandchafingtherim.2.Damagefromexcessiveheatsuchasanunusualappearanceortexture.,RejectionofTireThefollowingtiresmustbescraped:Anyevidenceofbreakscausedbyflexing（弯曲）.Thistypeofdamageisoftenassociatedwithotherdamagethatmaynotbevisible.Beaddamagetomorethanthechafers,oranydamagethatwouldpreventthebeadofatubelesstirefromsealingtothewheel.Anyevidenceofseparationbetweenthepliesaroundthebeadwire.,RejectionofTireThefollowingtiresmustbescraped:Anyinjurythatwouldrequireareinforcement.Kinkedorbrokenbeads.Weathercracksorradialcracksinthesidewallthatextendintothecordbody.Blistersorotherevidenceofheatdamage.Cracked,deteriorated,ordamagedinnerlinersoftubelesstires.,StorageofTireAllnewandretreadedtiresshouldbestoredinacool,dryarea,outofdirectsunlightandawayfromanyelectricalmachinery(Ozonedamage).Thetemperatureshouldbekeptbetween32Fand80F.Thetiresshouldbestoredverticallyinspecialrackswiththetiresupportedonaflatsurfacewhichisatleastthreeorfourincheswide.,StorageofTireStacktirehorizontally:1.theyshouldnotbestackedmorethanfivetireshighfortireswithadiameterofupto40inches.2.notmorethanfourtireshighforthosewithadiameterbetween40and49inches.3.notmorethanthreehighfortireswithadiameterlargerthan49inches.Figure9-84,AircrafttubesTwotype:1.Unreinforcedrubbertubefornormalapplication.2.Specialheavy-dutyreinforcedtubeincludealayerofnylonfabricmoldedtoinsidecircumferencetoprotectitfromchafingagainsttherimandfromheatcausedbybrakeapplication.Material:aspeciallycompoundednaturalrubberLeakagecauses:Aholeordefectivevalve,TubeInspectionLeakage:spreadadropofwaterovertheendofthevalvetocheckifthecoreisperfect.iftheleakisnotinthevalve,thetubemustberemoved,inflatedandputintoawatercontainertocheckforleakageasfollowing:,TubeInspection1.wheninflatingatirethatisnotinatire,onlyenoughairisusedtorounditout.2.checktheareacarefullyaroundthevalvestemandthevalvepadforanyindicationofthepadpullingawayfromthetube.3.theinnercircumferenceofthetubeshouldbeexaminedforevidenceofchafingagainstthetoeofthebead.4.theinnercircumferenceofthetubeshouldbeexaminedforanyheatedindication.Ithaslostitssmooth,contour-developedsquarecorners.,StorageofTubeTubesshouldbestoredinoriginalcartons.Theycanbedustedwithtiretalcum(滑石粉）wrappedinheavypaperTubescanbestoredinthepropersizetirewithinflation.Inflationpressureisjustenoughtorounditout.Neverhangtubesovernailsorpegs.,StorageofTubeDonotcauseanysharpfoldorcrease(摺痕，皱痕).Tubesshouldbestoredinacool,dry,darkareaawayfromanyelectricalequipment.Inspection:elasticity,cracking,evidenceofchafing.throughcheckofvalvestem,valvecoretightnessorleakage.checkforleaksbyinflationbeforeinstallation.,MountingofTireM.S.Mmustbefollowedindetailwhenmountingandremovingatire.Suchas:bolttorquelubricationrequirementwheelbalancing,MountingofTubelessTireInspectionbeforemounting:Nonicksorscratches（擦伤）inthebeadseatareaofthewheel.TheO-ringareaiscriticalfortubelesstire.(cleantheseareawithaclothdampenedwithisopropylalcohol异丙醇)NocorrosionoranyscratchedfinishonthewheelThermalfuseplugshouldbecheckedforsecurityandcondition.Theconditionoftheairvalve,MountingofTubelessTireInspectionbeforemounting:Assurethattireisapprovedtype.ThereisnoF.Oinsidethetire.Thebeadareashouldbewipedcleanwitharagdampenedwithisopropylalcohol.TheO-ringshouldbelubricatedwiththesamegreaseusedforthewheelbearingandiscarefullyplacedinthegroovewithoutstretchingortwisting.,MountingofTubelessTirePlacetheinboardwheelhalfonaclean,flatsurface.2.Thetireshouldthenbeplacedovertheinboardwheelhalfwiththereddotindicatingthetireslightpointadjacenttothewheelvalve,orifsomeothermarkonthewheelidentifiesitsheavypoint,adjacenttothatmark.3.Theoutboardwheelhalfisplacedinsidethetire,theboltholesarelinedup.,MountingofTubelessTire4.Paintananti-seizecompound(防咬剂）suchasLubtorkonthethreadsofboltsandnuts,bothsidesofwashers,andtheninstallboltsandnuts.5.Allthenutsaredrawnupincrisscrossfashiontoone-halfoftherequiredtorque,thenallofthefastenersaretightenedtofulltorque.Note:Wheelboltsshouldonlybetightenedusingaaccuratehand-torquewrench.Neveruseaimpactwrenchnanyboltwherethetorqueiscritical.Aseriesofblowsorjerkscreatestressesgreaterthantheboltisdesignatedtotake.,MountingofTubelessTire6.Thewheelandtireassemblyshouldbeplacedinasafetycage,theairpressureregulatorisadjustedtotherecommendedtirepressure,andtheninflatethetiregradually.Thetechnicianshouldwatchthetiretobesurethebeadseatsagainstthewheelflange.7.Allnylontiresstretchwhentheyareinitiallyinflatedandshouldbeallowedtoremainfor12to24hourswithnoloadapplied.Thepressureshouldbeadjustedafterthisperiod.8.Continuetomonitortheinflationpressurelossdaily,butitshouldnotexceed5%inany24-hourperiod.,MountingofTubeTire1.Thetireandtubemustbecorrectforinstallation.2.Anydamageorcorrosionofthewheelshouldbetreated.Corrosion-RemovalofdamagetracerestoringoxidefilmTwoc