ANTI-LOCK BRAKES potx

... Controlled together.DNot controlledD.Not controlledANTILOCK BRAKES ANTI-LOCK BRAKES ANTILOCK BRAKES ANTI-LOCK BRAKES  A three (3) channel ABS system control the rear wheel together ... 0% A lock-up wheel will have a wheel slippage of 100%of 100%ANTILOCK BRAKES ANTI-LOCK BRAKES  ABS, (Anti-Lock brake system)ABSallows the driver to maintain steeringABS allows ... situationssituations . Rear Backing PlateANTILOCK BRAKES ANTI-LOCK BRAKES  When operating a vehicle with ABS never pump the brakes. pp Doing so will make the ABS system ineffectiveineffective....

... standard. Field perform-Friction Materials 92Band Brakes Band brakes are simpler and less expensive than most other braking devices,with shoe brakes, as perhaps their nearest rival. Because of ... Figure 7 for steel brakes with sinteredlinings shows a change in A from a midrange value of about 0.25 to a midrangevalue of about 0.14, for a change of 44%. However, carbon–carbon brakes are lighter ... Publishers, New York.)Friction Materials 7Chapter 11 Fluid Clutches and Brakes 257I. Fluid Couplings as Clutches 257II. Fluid Brakes: Retarders 262III. Magnetorheological Suspension Clutch and...

... Inc.indicatesachangeinAfromapproximately0.45toapproximately0.07,forachangeof84.4%.Incontrasttothis,Figure7forsteelbrakeswithsinteredliningsshowsachangeinAfromamidrangevalueofabout0.25toamidrangevalueofabout0.14,forachangeof44%.However,carbon–carbonbrakesarelighterthansteelbrakesandcanbemadefromasinglematerial[11].F.OtherProprietaryMaterialsFrictionmaterialsproducedbymostmanufacturersareproprietarytotheextentthatnotalloftheiringredientsaredisclosed.Noneoftheingredientsmaybelistedforthoseliningmaterialsthatperformsatisfactorilywithoutcomponentsprovidedbyothers,suchasKevlar.AbsenceofasbestosalwayswillbenotedbyU.S.suppliers.Manymanufacturersofentirelyorpartiallyproprietaryliningsprovidedataonthenominalfrictioncoefficients,wear,andrecommendedtemper-aturerangesoftheirproducts,althoughafewwillsupplydataonlytoamanufacturingcustomer.Thisdatamaybeineithertabularorgraphicalform.TypicaltabulardatafordryliningmaterialsmaybesimilartothatshowninTable2,andtypicaldataforwet(oil,transmissionfluid)liningmaterialsmaybesimilartothatshowninTable3fortwodifferentliningmaterials.Thefirstofthese,GL483-110,isdescribedasalayeredKevlarmatwithembeddedcarbonparticlesthatarehighlywearresistant.Thislayeredcompositionisboundtogetherwithahighstrength,temperatureresistantphenolicsresin.Thesecond,GL383-114,isanon-asbestos,cellulosefibercompositefrictionpaperthatissaturatedwithasimilarphenolicsresin.(SeeFig.1.)Datainbothtableswereobtainedfromconditionsthatmaydifferfromthose ... composites arewidely used in brakes for large aircraft, such as long-range commercial jets,and in military aircraft. Their typical construction is shown in Figure 6. Brakes using sintered metal ... that press against steel plates are known assteel brakes, and those that press carbon lining material against carbon platesare known as carbon brakes in Figure 6. Stator plates are keyed to the...

... pressure upon the lining.Band Brakes 23Copyright © 2004 Marcel Dekker, Inc.2BandBrakesBandbrakesaresimplerandlessexpensivethanmostotherbrakingdevices,withshoebrakes,asperhapstheirnearestrival.Becauseoftheirsimplicity,theymaybeproducedeasilybymostequipmentmanufacturerswithouthavingtopurchasespecialequipmentandwithouthavingtousefoundryorforgingfacilities.Onlytheliningmustbepurchasedfromoutsidesources.Bandbrakesareusedinmanyapplicationssuchasinautomatictransmissions(Figure1)andasbackstops(Figure5—devicesdesignedtopreventreversalofrotation),forbucketconveyors,hoists,andsimilarequipment.Theyareespeciallydesirableinthelast-mentionedapplicationbecausetheiractioncanbemadeautomaticwithoutadditionalcontrols.I.DERIVATIONOFEQUATIONSFigure2showsthequantitiesinvolvedinthederivationoftheforcerelationsused ... band.Band Brakes 21Copyright © 2004 Marcel Dekker, Inc.FIGURE6 Positive discharge bucket conveyor cutaway and cross section.(Courtesy American Chain Association, Washington, DC.)Band Brakes ... eÀAaÞ¼pmaxwr2ð1 À eÀAaÞð1-10ÞChapter 220Copyright © 2004 Marcel Dekker, Inc.FIGURE1 Band brakes used in an automatic transmission system.Copyright © 2004 Marcel Dekker, Inc.moving side...

... Inc.shoeisstronglydependentonthewidthofthepressuremaximuminthevicinityoftheadjustinglink,themagnitudeofthebrakingtorquecontributedbythesecondaryshoedoesnotchangequiteasrapidlyasthechangeintheliningpressureatthetoe.VII.ELECTRICBRAKESCommonusagehasassociatedthetermelectricbrakeswithfrictionbrakeswhichareelectricallyactivated,ratherthanwiththosebrakesthatrelyuponelectricalandmagneticforcesratherthanfrictiontoprovidethebrakingtorque.TypicalelectricbrakesarepicturedinFigures18and20.Botharesingle-anchor ... designsolutions.I. PIVOTED EXTERNAL DRUM BRAKES A. Long Shoe Brakes Externally pivoted, long shoe brakes similar to that shown in Figure 1 areoften used as holding brakes. As its name implies, a holding ... Inc.shoeisstronglydependentonthewidthofthepressuremaximuminthevicinityoftheadjustinglink,themagnitudeofthebrakingtorquecontributedbythesecondaryshoedoesnotchangequiteasrapidlyasthechangeintheliningpressureatthetoe.VII.ELECTRICBRAKESCommonusagehasassociatedthetermelectricbrakeswithfrictionbrakeswhichareelectricallyactivated,ratherthanwiththosebrakesthatrelyuponelectricalandmagneticforcesratherthanfrictiontoprovidethebrakingtorque.TypicalelectricbrakesarepicturedinFigures18and20.Botharesingle-anchor drum brakes that use the servo action associated with these brakes to obtain the required braking...

... aLinearly Acting External and Internal Drum Brakes 81Copyright © 2004 Marcel Dekker, Inc.4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams ... Inc.4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams ... Inc.4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams...

... diskbrakes,whichconsistoftwodisksseparatedbyradialvanes,sothatadditionalcoolingsurfaceisprovided,asshowninFigure7.Ventilationalsoincreasesbrakelife,asimpliedbytherepresentativebrakepadlifeasafunctionofthesurfacetemperatureasgiveninFigure8,wherethelongestlifeisrealizedforthatpadandcalipercombinationwhichprovidesthelargestheatsink,showninFigure9andtheshortestlifeforthatwiththesmallestheatsink,showninFigure10.III.ANNULARCONTACTDISKBRAKESANDCLUTCHESAnnularcontact,orfacecontact,diskbrakesareavailableeitherasdrymultiple-platediskbrakes,asshowninFigure2,oraswetmultiple-platedisk brakes, asshowninFigure3.Theirconstructionissimilartothatofmultipledisk ... Inc.5DryandWetDiskBrakesandClutchesThischapterondiskbrakesandclutcheswillconsiderannularcontactdiskclutchesandbothcaliperandannularcontactdiskbrakes,asillustratedinFigures1,2,and3.Caliper disk brakes, ... consultedfor the details of mathematical analysis.II. VENTILATED DISK BRAKES Although disk brakes are less susceptible to fade than drum brakes, they willbe heated by friction, which may lead to brake...

... for the frictioncoefficients, A, indicated.Cone Brakes and Clutches 119Copyright © 2004 Marcel Dekker, Inc.6ConeBrakesandClutchesThesebrakeshavetheadvantageofgreatertorqueforasmalleraxialforcethaneithertypeofdiskbrakediscussedinChapter5.Themagnitudeoftheimprovementislimited,however,bytheobservationthatforsmallconeanglesadisengagementforcemayberequired,dependingonthefrictioncoefficient,becausetheinnerandouterconesmaytendtowedgetogether.Thisisbecauseonengagementtheinnerconeisradiallycompressedandtheouterconeisradiallyenlargedasthebrakeisengaged.Forsmallconeanglestheinducedfrictionforcedominatesthenormalforce,whichtendstoexpeltheinnercone,sothatanexternalforceisrequiredforseparation.Thischaracteristic,however,maybeusefulinthoseapplicationswhereabrakeistoremainengagedinthepresenceofdisengagementforces.I.TORQUEANDACTIVATIONFORCEThepertinentgeometryoftheconebrakeisshowninFigure1.Iftheinnerandouter ... Inc.II.FOLDEDCONEBRAKEPrototypeconebrakeshavebeendesignedandtestedforarangeofvehiclesizes,fromtractorsandtrailerstosubcompactautomobiles[1].Boththelargeandsmallsizesusedafoldedconedesign,asillustratedinFigures5and6,eachwitha=27j.Althoughtheconebrakehasfewerpartsthandrum brakes, thisadvantagemustbebalancedagainstthedisadvantageofrequiringanoutboardwheelbearing.Analysisofthefoldedconebrakewithasectorshoe,showninFigure5,toobtaindesignformulasforthetorquecapabilityandtherequiredactiva-tionforceisquitesimilartothatusedforsimpleconebrakesandclutches.SincethebrakesillustratedinFigures5and6useasectorpad,webegintheanalysisbyobservingfromFigure7(a)thatanelementofareaontheconicalsurfacemaybewrittenasda¼rdudrsinað2-1ÞFIGURE4DesignregionsintheA,aplaneforconeclutches /brakes. Cone ... Inc.II.FOLDEDCONEBRAKEPrototypeconebrakeshavebeendesignedandtestedforarangeofvehiclesizes,fromtractorsandtrailerstosubcompactautomobiles[1].Boththelargeandsmallsizesusedafoldedconedesign,asillustratedinFigures5and6,eachwitha=27j.Althoughtheconebrakehasfewerpartsthandrum brakes, thisadvantagemustbebalancedagainstthedisadvantageofrequiringanoutboardwheelbearing.Analysisofthefoldedconebrakewithasectorshoe,showninFigure5,toobtaindesignformulasforthetorquecapabilityandtherequiredactiva-tionforceisquitesimilartothatusedforsimpleconebrakesandclutches.SincethebrakesillustratedinFigures5and6useasectorpad,webegintheanalysisbyobservingfromFigure7(a)thatanelementofareaontheconicalsurfacemaybewrittenasda¼rdudrsinað2-1ÞFIGURE4DesignregionsintheA,aplaneforconeclutches /brakes. Cone Brakes and Clutches 113Copyright © 2004 Marcel Dekker, Inc.where we again use the pressure...

... Eddy-Current Brakes 143Copyright © 2004 Marcel Dekker, Inc.IV. EDDY-CURRENT BRAKES AND CLUTCHESConstruction of eddy-current brakes is physically similar to that of hysteresis brakes. The essential ... coil.Magnetic Particle, Hysteresis and Eddy-Current Brakes 127Copyright © 2004 Marcel Dekker, Inc.II.MAGNETICPARTICLEBRAKESANDCLUTCHESThesebrakesareavailableinarangeofsizesthatincludethe100-lb-ftmodelshowninFigure3andthe8-lb-ftmodelshowninFigure4.Sincethesecon-figurationsareequallysuitedforclutches,theymaybecombinedtoformclutch-brakecombinations,asinFigure5.Whenusedasaclutch,theunithastwomovingparts;whenusedasabrakeithasonlyone.Whenusedasaclutch,theconfigurationisasrepresentedbythesche-maticinFigure6(a).Theinputshaftisattachedtoacylindricaldrum,termedthe ... losses in eddy-current clutches and brakes, just asthere are small eddy-current losses in hysteresis clutches and brakes, theprimary source of power loss in these brakes is in the generation of...

... Inc.theannularcaliperandannulardiskbegivenbyequation.Accordingly,eval-uatetheformulasT¼pmaxwr2oð1ÀeÀAfÞð8-7Þforabandbrake,T¼2Apmaxwr2osinfo2ð8-8Þforeithertwoopposinginternalorexternallinearlyactingbrakeshoes,T¼2Apmaxr3o3ffiffiffi3pfoð8-9Þfortwoopposingdiscbrakepads,eachsubtendingangleBo,andT¼4kApmaxr3o3ffiffiffi3pð8-10ÞfortwocompleteannularpadsinwhichBo=2kinequation(8-9).WeshallalsoconsideranexternalpivoteddrumbrakewithaleadingandtrailingshoethatmaybeevaluatedbyinvokingtheprogramusedinChapter3.Inallofthesecalculationsassumeafrictioncoefficientof0.3,andsetthewidthfortheband,thelinearlyactingdrumbrake,andtheexternallypivotedbraketo5cm.Limitthemaximumliningpressureforthebandbrakeandfortheexternallypivotedbraketo2.0MPa,andlimitthepressurefortheotherliningsto3.0MPa,whichmaybeeitherformedorsolid.Liningpressurefortheexternallypivotedbrakewastakentobe2.0MPa,merelyforcomparisonwiththebandbrake.Figure11(a)showsthetorquecapacityinnewton-metersasafunctionofangleBsubtendedbyeachshoeforadrumdiameterof300mm,andFigure11(b)showsthetorquecapacityinnewton-metersforband,linearlyacting,caliper,andannularbrakesasafunctionofthedrumordiscdiameterinmillimeters.AlthoughthelinearlyactingdrumbrakeisclearlymoreeffectivethantheotherbrakesshowninFigure11(b),itandalloftheotherthreebrakesinthatfigurerequiremorehardwarethandoesthebandbrake.Therefore,selectthebandbrake,becauseitcanprovidethenecessarytorquecapabilitywithmechanicalsimplicity.Externaldual-shoedrumbrakesarethenextsimplest.Increasingthemaximumliningpressureto3.0MPaforanexternallypivoteddual-shoebrakeallowsthedrumdiametertobereducedto170mmandtheradialdistancetotheshoepivottobereducedto100mm,fromthe150mmas-sociatedwithFigure11(a),togetatorquevs.anglecurvesimilarinshapeandmagnitudetothatinFigure11(a).Thus,eitheranexternallypivotedChapter8174Copyright ... Inc.rollersopposesthemotionoftheweb.Theclutchatthedriverollsmaybeselectedonthebasisoftorquealonebecauseitwillexperienceonlyslightheatingduetocolllossesaslongasthewebmovesatthedesignvelocity.Webvelocityatthedriverollsmaybecalculatedfromv¼kdn¼kð0:1Þð950Þ¼298:451m=minBasedonlabresultsweestimatethatwebvelocityatdrawroller1willbe297.141m/min,correspondingtoarotationalspeedofn1¼vkd¼297:141kð0:130Þ¼727:561rpmThetorquerequirementatdrawrolls1isgivenbyT¼rF¼0:065ð110Þ¼7:150N-mCoolingrequirementsatthebrakesmaybegreatlyreducedifthedifferentialspeedatthebrakesisreducedbyinstallingthembetweenthedrawrollsandamotorthatiscontrolledtoresistrotationalspeedsgreaterthanaspecifiedvalue,asillustratedinFigure18.Ifthesemotorsaretooperate ... Inc.Thekineticenergiesmaybefoundfromn14¼116n24¼13:2n34¼13:2m1¼1278m2¼276m3¼721m4¼231r1g¼0:81r2g¼0:17r3g¼0:32r4g¼0:09Ig1¼m1r21gIg2¼m2r22gIg3¼m3r23gIg4¼m4r24gId¼mdr2dgked¼12Idn214keg1¼12Ig1n214keg2¼12Ig2n224keg3¼12Ig3n234keg4¼12Ig4wherem1throughm4arethemassesofgears1through4,respectively,andr1gthroughr4garetheirrespectiveradiiofgyration.Thus,KEd¼kedN2m¼185:5N-mKEL¼12mLv2c¼957:3N-mKEr¼12mrv2c¼49:2N-mKEg1¼keg1N2m¼4224:5N-mKEg2¼keg2N2m¼1004:7N-mKEg3¼keg3N2m¼9299:2N-mKEg4¼keg4N2m¼2413:3N-mAdditionofthesegivesKE¼ðkeg1þkeg2þkeg3þkeg4þkedÞN2mþKELþKEr¼18;133:6N-mSouponaddingthistothetotalpotentialenergyofPE¼23;202:3N-mthetorquerequiredmaybefoundfromTo¼PEþKEðNm=2Þt¼813:9N-mð8-6ÞinwhichtheaveragemotorspeedduringbrakingwastakentobeNm/2.Thebrakingrequirementof813.9N-mmaybemetbyusingavarietyof brakes, suchasband,externallinear,annularcaliper,andannulardisk brakes. Tochooseamongthese,recallequation(1-10)fromChapter1,equa-tion(2-1)fromChapter4,andequations(1-7)and(3-5)fromChapter5corresponding...