1.-輪胎模具簡介

TireMould

BackgroundofTheTire

Inordertohavebetterunderstandingaboutthetiremould,wegettohaveaclearmindaboutthetirecategoriesspecifications.

AccordingtotheshapeTreadpatternsincommercialtirescanberoughlydividedintofourgroupsaccordingtotheshape:1.Asymmetric,[asi’metrik]2.Unidirectional,3.Ribshape,4.Blockshape.

Accordingtofunctions

But,ifaccordingtofunctionsofthetire,thetirecanbedividedinto:1.Generallytire,2.Allseasontire,3.Snowtire,4.On/offtheroadtire,5.Offtheroadtire.GenerallyTireTiresgenerallyhaveatreadthatiswell-suitedforaspecificvehicleapplication.Forexample,pneumatictiresusedprimarilyonpavedsurfacesgenerallyhaveahighproportionofthetreadincontactwiththeroad.Thesetiresgenerallyhaveanet-to-grossratioinexcessof70%.

Thismeansthat70%ormoreoftheareawithinthetires'footprintorcontactpatchistouchingtheroadwhile30%lessisthevoidarearepresentingthetires'grooveswithinthefootprintarea.Thesetires,dueinparttothelargeamountoftreadincontactwiththeroad,canyieldverygoodtreadmileagesometimesinexcessof75,000milesduringthetires'normallife.AllseasontypetiresAllseasontireshavesomewhatlaterallyextendinggroovesineachshoulderofthetread.Theselateralgroovesenhancesnowtractionperformance.SnowTiresIf,however,thevehicleownerwantsincreasedtractiononsnow,tireshavingamoreaggressiveopentreadpatternhavebeenusedforthispurpose.Thesesnowtiresgenerallyhavealowernet-to-grossratioandalmostalwaysalargeamountofleadingedgesonblockelementstoprovideincreasedtraction.SkidproofpinOn/OffRoadTireWhenthevehicleownerwantsatirethatcanoperatebothontheroadwaysaswellasinsnow,mudandsand,hegenerallymustselectanon/offroadtread.Off-RoadTireTypically,aseriousoff-roadenthusiastmaychooseatiredesignatedasamudtire.Thesetiresareveryopen,tendingnottocloginthemud.TheGoodyearWRANGLERMT.TheMT,mudtiredesignationhassignifiedtooff-roadenthusiastthatthetirewaswell-suitedforoff-roadapplications.Ameasureofthetires'off-roadworthinesswasoneofitsfirstapplications,theU.S.ArmyHummervehicle.TireTreadPatternDesignTiredesignandmorespecificallytreadpatterndesignplaysacriticalroleinthesafeandefficientoperationofavehicle.Forexample,itisknownthatthetreadpatternassistsinthegenerationof1.steeringforces,2.driving,3.brakingforces.4.reducingroadnoise,5.providingsuperiorgripcapabilitiesinbothwetanddrydrivingconditions,6.minimizingrollingresistancetoincreasetheoverallfueleconomyofthevehicle.

Inpractice,thedesignofatiretreadpatternalsorequiresthebalancingofmanycontradictorydemands.Findingtheproperstructurethatbalancesthesedemandsforanygiventireisthusagreatchallenge.Forthisandotherreasons,engineerstypicallyfocusonalargearrayofconsiderations,placingemphasisoncertaindesigncriteriaoverothers,dependingonthespecificapplicationofthetire.However,byfocusingoncertaindesigncriteria,othercriteriasuchastirewearorstresscomponentsmaynothavebeenweighedasheavilyduringthedesignstage.

Bywayofamorespecificillustration,onedesignapproachhasbeentoformgroovesbetweenribswithnegativelyslopedwallstoincreasegrippingcapabilities.However,insuchanapproach,thegroovesaremorelikelytotrapandretainstones,whichcandamagethetire.Anotherexampleisintheuseofall-seasontires,whichcustomarilyemployblockelementsintheirtreaddesign.Thesedesignshavesuperiorgripperformancebuttendtohaveincreasednoiselevel,aswellashaveatendencytowardirregularweardueprimarilytotheirlackofstiffnessinthecircumferentialdirectionofthetread.Suchnoisegenerationandirregularwearareaccentuatedatacuteorsharpanglesintherubberblocksformedbyintersectionsofgroovewalls.

Inexaminingthecomplexmechanismsinvolvedinpropertreadpatterndesign,severalfactorsplayaroleinthefinaldesignofthetreadpattern.Thesefactorsinclude,1.Industrystandards,2.Governmentregulations,3.Customerspecifications,4.Marketingrequirementsandthelike.FinaldesignfactorsComplexdesignmechanismsOntheotherhand,thecomplexmechanismswhicharetakenintoaccountinthedesignofthetreadpatterninclude,1.Amongstothermechanisms,2.Stressesgenerateduponthetireduringdrivingconditions,energylossesduetorollingresistance,3.Sidewallflexing,Toahostofothermechanisms.Thus,thedesignofatreadpatternisnotatrivialtaskand,infact,isquitecomplexrequiringtheneedtotakeintoaccountmanydifferentconsiderations.Inanyevent,tirepatternshavecommonpatterntraits.Thesecommonpatterntraitsinclude,forexample,grooveswithsharporacuteanglesintransitionalareas,e.g.,betweentreads,verticalwallsformingthegroovesortreads,etc.

Ithasbeentheorizedthatsuchdesignshavelargestresscomponentswhichconjugateatthesharpangles,aswellasresultinincreasedroadnoiseandrollingresistance.Ofcourse,engineersareconstantlydesigningtreadpatternstoincreaseoveralltireefficiency,butthesedesigntraitsremainpervasive.Whatmakesofagoodtire?Ingeneral,tiresintendedforuseonthesteeringaxleandforlongmotorwayjourneysneed:1.goodevennessofwear;2.agoodmileage;3.gooddirectionalstabilityandsteeringprecisionondrysurfaces;4.goodgriponwetsurfaces;5.goodresistancewithrespecttotearingofthetreadandtolateralshocks;6.lowrollingresistance;7.theabilitytoexpelsmallstonestrappedinthegrooves.Factorscontributingtoproducingthesefeaturesarethetreaddesign,theprofileoftheinflatedtireandthestructureofthetire.TireSidewallDesignManufacturershaveformanyyearsplaced1.numerals,2.letters,3.charactersorotherde