Clutches and brakes design and selection P1

... processes through overhead cranes, hoists, and industrial brakes and clutches and in farm and garden tractors. Some or all of the following materials, and others, that are now nec- essary to produce ... 1379 kPa (200 psi) and a temperature no greater than 260jC (500jF) when in either a wet (oil) or a dry environment. This lining material may be used for band brakes and band clutches that work ... liningsandclutchfacingsforbothwet(oilbath)anddryclutchapplications. Indrybrakeandclutchapplications,aflexible,nonwovenformcan withstanddynamicpressureupto3100kPa(450psi),arenonabrasivetoiron, steel,andcoppersurfaces,anddisplayandnominalcoefficientoffrictionof...

... Inc.Thistypeofdriveisaninexpensivealternatetobevelgearsforaright-angledrive,aclutch,andareversingmechanism.Whentheright-handconeinFigure8ismoveddownwardtocontacttheupperhalfofthedoubleconeandtheleft-bandconeismovedupwardtocontactthelowerhalfofthedoublecone,boththeleft-andright-handconesrotateinthesamedirection.Iftheright-andleft-handconesdrivetheright-andleft-handwheelsofalawnmower,themowermovesforward.Iftheright-handconeismoveddownwardandtheleft-handremainsdownward,thewheelstheydriveturninoppositedirectionsandthemowerrotatesinitsownlengthtoprovidethezeroturningradius.(Theunpoweredfrontwheelsareoncasters.)Finally,iftheright-handconeremainsdownwardandtheleft-handconeismovedupward,themowermovesinreverse.Contactbetweenconeswouldbealongalinewherethegeneratorsofeachconeareincontactiftheconeswereabsolutelyrigid.However,theelasticityoftherelativelysofterconeliningsformacontactstripcenterdalongwhatwouldhavebeenthecontactline.Againtherearetwopossiblemodesoftorquetransfer;onewithnoslipatsomepointortransverselinewithinthecontactregionandslipelsewhere,andtheotherwithslipeverywherewithinthecontactarea.AsillustratedinFigure9,ifslippageatallbutonepointorlineisassumedtooccurwhentworotatingconesareincontact,thenthespeedofthedrivenconewilldependuponthelocationoftheno-slippointortransverseline.FromFigure9itisevidentthatwitheitherpointorlinecontact,theangularvelocityoftheoutputconesmayfallsomewherebetweenthelimitsdeterminedbythelocationofthatpoint,orline,withinthecontactstripwhereFIGURE8Conefrictiondriveschematic.Centraldoubleconedrivesoutputconeson ... Inc.Substitutionfromtherelationsforr1andr2yieldsr2Àr1¼l2Àl1ðÞsinfandr2þr1¼l2þl1ðÞsinfSowithpw(l2Àl1)=N=VsinfwehaveT¼AVl2þl12sin2fð3-13ÞIV.EXAMPLEI:BELTDRIVE,HINGEDMOTORMOUNTWouldyouapproveamotormountasillustratedinFigure1(a)forclutchinganddeclutching?Themassofthemotoris18.6kgandthecenterofthemotorshaftis12cmabovethebottomofthemotor’sbase,whichis17.8cmwide.Center-to-centerdistancebetweentheshaftofthemotorandtheshaftofthedrivenmachineistobe50cm.Belttensionistobe298.5N,thebeltshouldbereplacedafterthecenterdistanceincreases2.4cm,theangleofthelinebetweencentersmaybefrom15jto20jwiththehorizontal,andtheshaftofthedrivenmachineisaboveandtotherightofthemotorshaft.ThegravitationalforceonthemotorisgivenbyW=mgintermsofthemassofthemotorandtheaccelerationofgravity.ThusW¼18:69:8067ðÞ¼182:4NtogiveT/W=1.637.Fromthemotorspecifications,b=12cmandamustbeequaltoorlargerthan17.8/2=8.9cm.Asanaidtoselectingavaluefora,plotT/Wasafunctionofsforf=20jand30jandforu=20jand30j,asshowninFigure14.Selectf=20jandcomparedesignsusingu=20jandu=30j.Useoff=15jwasrejectedinordertoavoidexcessivebelttensionasthebeltstretches.Considers=0.2tohavealargerT/Wratioandconsiders=0.685,correspondingtoa=13cm,togetamorecompactmounting.Thusa=44.5mmfors=0. 2and1 3mmfors=0.685.SincebeltelongationduringusecanalterthegeometryshowninFigure15bychangingangleuandtherebychangingthebelttension,calculatethe ... Nd1ld1ln1tan2f and Nn2¼Ndrd2rn2¼ Ndld 2ln2tan2fð3-1Þwhere rd1 and rnlare the radii of the driver and driven cones, respectively, atpoint 1, rd 2 and rn2are driver and driven...

... 11FluidClutchesandBrakesFluidclutchesandbrakesmaybedividedintotwogroups:thosecontainingafluidonlyandthosecontainingamixtureoffluidsandsolids.Thosecon-tainingonlyafluidrelyprimarilyuponthemassofthefluidandsecondarilyuponitsviscositytotransmittorque.Unitscontainingbothafluidandasolidinaparticulateformrelyuponthesuspendedsolidstoprovidethemajorbondbetweenthecomponentsthateithertransmitorresisttorquewhenun-dertheinfluenceofanexternalelectromagneticfield.Theadvantageoffluidclutchesandbrakesisthatthereisnoliningtowearandreplace.This,however,isobtainedattheexpenseofsomepowerlossinthetransmissionoftorqueandthedistinctneedforsomesortoffluidcoolingforbothfluidclutchesandfluidbrakes.Moreover,occasionalfluidsealreplacementmayalsoberequired.I.FLUIDCOUPLINGSASCLUTCHESFluidcouplingsmayserveassoftstartclutchesandastorquelimiting clutches. Atypicalfluidcouplingconsistsofaninputshaftattachedtoanimpellerandanoutputshaftattachedtoarunner,withbothencasedwithinaclosedhousingandorientedasshowninFigure1.AnimpellermaydifferfromarunnerintheshapeoftheradialvanesofthesortshowninFigure2andmaybeattachedto,androtatewith,thehousingthatcontainsboththeimpellerandtherunner.AsindicatedinFigure1,theshaftsaresupportedbybearingsatthehousingandbybearingsatthefarendsofeachshaftthatinturnaresupportedbyanenclosure,asshowninFigure3.EachimpellerandCopyright ... 11FluidClutchesandBrakesFluidclutchesandbrakesmaybedividedintotwogroups:thosecontainingafluidonlyandthosecontainingamixtureoffluidsandsolids.Thosecon-tainingonlyafluidrelyprimarilyuponthemassofthefluidandsecondarilyuponitsviscositytotransmittorque.Unitscontainingbothafluidandasolidinaparticulateformrelyuponthesuspendedsolidstoprovidethemajorbondbetweenthecomponentsthateithertransmitorresisttorquewhenun-dertheinfluenceofanexternalelectromagneticfield.Theadvantageoffluidclutchesandbrakesisthatthereisnoliningtowearandreplace.This,however,isobtainedattheexpenseofsomepowerlossinthetransmissionoftorqueandthedistinctneedforsomesortoffluidcoolingforbothfluidclutchesandfluidbrakes.Moreover,occasionalfluidsealreplacementmayalsoberequired.I.FLUIDCOUPLINGSASCLUTCHESFluidcouplingsmayserveassoftstartclutchesandastorquelimiting clutches. Atypicalfluidcouplingconsistsofaninputshaftattachedtoanimpellerandanoutputshaftattachedtoarunner,withbothencasedwithinaclosedhousingandorientedasshowninFigure1.AnimpellermaydifferfromarunnerintheshapeoftheradialvanesofthesortshowninFigure2andmaybeattachedto,androtatewith,thehousingthatcontainsboththeimpellerandtherunner.AsindicatedinFigure1,theshaftsaresupportedbybearingsatthehousingandbybearingsatthefarendsofeachshaftthatinturnaresupportedbyanenclosure,asshowninFigure3.EachimpellerandCopyright ... 11FluidClutchesandBrakesFluidclutchesandbrakesmaybedividedintotwogroups:thosecontainingafluidonlyandthosecontainingamixtureoffluidsandsolids.Thosecon-tainingonlyafluidrelyprimarilyuponthemassofthefluidandsecondarilyuponitsviscositytotransmittorque.Unitscontainingbothafluidandasolidinaparticulateformrelyuponthesuspendedsolidstoprovidethemajorbondbetweenthecomponentsthateithertransmitorresisttorquewhenun-dertheinfluenceofanexternalelectromagneticfield.Theadvantageoffluidclutchesandbrakesisthatthereisnoliningtowearandreplace.This,however,isobtainedattheexpenseofsomepowerlossinthetransmissionoftorqueandthedistinctneedforsomesortoffluidcoolingforbothfluidclutchesandfluidbrakes.Moreover,occasionalfluidsealreplacementmayalsoberequired.I.FLUIDCOUPLINGSASCLUTCHESFluidcouplingsmayserveassoftstartclutchesandastorquelimiting clutches. Atypicalfluidcouplingconsistsofaninputshaftattachedtoanimpellerandanoutputshaftattachedtoarunner,withbothencasedwithinaclosedhousingandorientedasshowninFigure1.AnimpellermaydifferfromarunnerintheshapeoftheradialvanesofthesortshowninFigure2andmaybeattachedto,androtatewith,thehousingthatcontainsboththeimpellerandtherunner.AsindicatedinFigure1,theshaftsaresupportedbybearingsatthehousingandbybearingsatthefarendsofeachshaftthatinturnaresupportedbyanenclosure,asshowninFigure3.EachimpellerandCopyright...

... between values E1 and E2, in which E1may be 10% and E2may be 20%, for example. This may beachieved by returning to equation (1-4) and solving for v1 and then replacingv1 and v0with the ... first patent for antilock brakes was granted in Germany in 1905 [1], and the first antilock brakes for railroad cars were available in 1943 [2].Electronic control of antilock brakes was widely incorporated ... The data collection,analysis, and system design involved may suggest initial procedures to befollowed for clutch and brake automation in other applications. Design of an antilock system (ABS)...

... brakeassembly (drum, backplate, shoes, and lining in the case of drum brakes and disk and caliper in the case of disk brakes) as it vibrates and have shown thatbrake vibration is the result of an interplay ... Inc.II.RECENTEXPERIMENTALDATAUsingexperimentaltechniquesnotavailableinthe1960sfortheexaminationofbothdiscanddrumbrakevibration,Felske,Hoppe,andMattha¨iemployedholographicinterferometrytodemonstrateconclusivelythatitisthecalipervibrationthatisthemajorcontributortobrakenoisefromdiskbrakes[11]andthebackplatevibrationthatisthemajorcontributorfromdrumbrakes[12].Typicalstandingwaveshapes,orthenodalpatterns,forthediskareshowninFigures 2and3 .VibrationofthecaliperisshowninFigures 4and5 .Thealternatingblackandwhitelineboundariesrepresentcontourlines,orelevationlines,onthecaliperanddiskandconsequentlymeasurethede-flectionofthediskandcaliperinadirectionperpendiculartotheplaneofthephotograph,asindicatedinFigure6foranantinodeonthedisk.FIGURE3 ... serve to dampen and suppress high-frequency vibration, and the pad material, central plate, and grooves may aid to suppress low-frequency vibration.Grooves in brake pads of caliper brakes also aid...

... Performance Standard, Power Press Brakes R(2002).BSMI B2004400: Hand Brakes for Bicycles.BSMI B4003700: Axles with Brakes of Trailer for Power Tiller.Engineering Standards for Clutches and Brakes ... rNormung(DIN).Italy:EuteNazionaleItalianodiUnificazione(UNI).Japan:JapaneseIndustrialStandards(JIS).Korea:KoreanStandardsAssociation(KSA).Malaysia:StandardsandIndustrialResearchofMalaysia(SIRIM).Netherlands:NederlandsNormalisatie-Instituut(NEN).Norway:NorwegianStandardsAssociation(—)Slovenia:StandardsandMetrologyInstitute(SMIS).Taiwan:BureauofStandardsandMetrologyInstitute(BSMI).UnitedStates:DepartmentofDefense(DoD—STD—),(MIL—).A.SelectedStandardsfromtheseOtherOrganizationsThetitlesofthefollowingstandardswerecopiedfromtheNSSNWebsiteasapartialindicationofthetopicsandapplicationsconsidered.Atthistimeofthiswriting,thestandardslistedbyNSSNmaybefoundbygoingtowww.ossn.org,wherealeft-clickofacomputermouseonthewordsSearchforStandards,whicharedirectlyunderthewordswww.NSSN.ORGatthetopleft ... 14Engineering Standards for Clutches and Brakes I. SAE STANDARDSFifteen of these standards for the year 2003 that pertain to brake or clutchcomponents...

... and Eddy-CurrentBrakes and Clutches 125I. Theoretical Background 126II. Magnetic Particle Brakes and Clutches 130III. Hysteresis Brakes and Clutches 132ContentsxIV. Eddy-Current Brakes and Clutches ... Collection 81Chapter 5 Dry and Wet Disk Brakes and Clutches 83I. Caliper Disk Brakes 84II. Ventilated Disk Brakes 91III. Annular Contact Disk Brakes and Clutches 92IV. Design Examples 99V. Notation ... together the formulas for thedesign and selection of a variety of brakes and clutches. The second is toprovide flowcharts and programs for programmable calculators and personalcomputers to facilitate...

... 2BandBrakesBandbrakesaresimplerandlessexpensivethanmostotherbrakingdevices,withshoebrakes,asperhapstheirnearestrival.Becauseoftheirsimplicity,theymaybeproducedeasilybymostequipmentmanufacturerswithouthavingtopurchasespecialequipmentandwithouthavingtousefoundryorforgingfacilities.Onlytheliningmustbepurchasedfromoutsidesources.Bandbrakesareusedinmanyapplicationssuchasinautomatictransmissions(Figure1)andasbackstops(Figure5—devicesdesignedtopreventreversalofrotation),forbucketconveyors,hoists,andsimilarequipment.Theyareespeciallydesirableinthelast-mentionedapplicationbecausetheiractioncanbemadeautomaticwithoutadditionalcontrols.I.DERIVATIONOFEQUATIONSFigure2showsthequantitiesinvolvedinthederivationoftheforcerelationsused ... the lining material and the drum, p represents the pressure betweenthe drum and the lining, and w represents the width of the band. Uponsimplifying equations (1-1) and (1-2) and remembering that ... the element ofband length approaches zero, sin(du/2) approaches du/2, cos(du/2)FIGURE2 Quantities and geometry used in the derivation of the band-brake design relations.Band Brakes 19Copyright...

... f0ð1-14ÞExternally and Internally Pivoted Shoe Brakes 37Copyright © 2004 Marcel Dekker, Inc.3ExternallyandInternallyPivotedShoe Brakes TypicalexternallyandinternallypivotedshoebrakesareshowninFigures1 and ... brake life, heatdissipation, fading, and braking torque capability.III. DESIGN OF DUAL-ANCHOR TWIN-SHOE DRUM BRAKES For both external and internal shoes and for either direction of rotation ... Inc.rotatesawayfromthepivot,self-lockingcanbeavoidedifMf/MpisalwaysgreaterthanÀ1.Similarcriteriaholdforinternalbrakesexceptthatthedirectionsofrotationarereversedforthesamealgebraicsigns.Sincemostbrakesaredesignedforrotationinbothdirections,itisgenerallyconvenienttocombinethesecriteriaintoasinglecriterion,whichisthatself-lockingofbothinternalandexternaldrumbrakesmaybeavoidedifÀ1VMfMpVþ1ð3-3ÞSelectionofshoeanddrumanglesanddimensionsinaccordancewiththiscriterionmaybeaidedbyconstructionofdesigncurvessuchasillustratedinFigures 7and8 ,inwhichtheratioMf/AMpisplottedagainstanglef2forselectedvaluesofthecoefficientoffriction.ExternalshoesarecharacterizedbyR/rratiosgreaterthanunityandinternalshoesbyr/Rratioslessthanunity.TheratioMf/AMphasbeenplottedinsteadofMf/MpinFigures 7and8 because...

... 4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams ... 4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams ... 4LinearlyActingExternalandInternalDrumBrakesLinearlyactingdrumbrakesarethosefittedwithshoeswhich,whenacti-vated,approachthedrumbymovingparalleltoaradiusthroughthecen-teroftheshoe.TypicallinearlyactingdrumbrakesareillustratedinFigures1–3.Analysisoflinearlyactingbrakesincludesthoseinwhichthecentrallypivotedshoesareattachedtopivotedlevers,asinFigure1.Includingbrakesofthisdesignwithinthecategoryoflinearlyactingbrakesisjustifiediftheyaredesignedsothattheappliedforcesontheshoesandliningsactalongtheradiioftheshaftsthattheygripwhenthebrakesareapplied.Brakesofthistypemayacteitheruponbrakedrumsordirectlyuponrotatingshaftsandaresuitableforuseinheavy-dutyapplications,suchasfoundinminingandconstructionequipmentandinmaterials-handlingmachinery.Internallinearlyactingdrumbrakes,suchasusedontrucksinEurope,maybedesignedasinFigure2.Eitherpneumaticorhydrauliccylindersorcams...