1. clutch

A clutch is a mechanical device which engages and disengages power transmission especially from driving shaft to driven shaft.

1. ER. PEEYUSH CHAUHAN
(DEPARTMENT OF MECHANICAL ENGINEERING)

2. “Aclutchisamechanicaldevicewhichengagesand
disengagespowertransmissionespeciallyfrom
drivingshafttodrivenshaft.”
Inthesimplestapplication,clutchesconnectand
disconnecttworotatingshafts(driveshaftsorline
shafts).
Inthesedevices,oneshaftistypicallyattachedtoan
engineorotherpowerunit(thedrivingmember)
whiletheothershaft(thedrivenmember)provides
outputpowerforwork.

3. Theveryfirstprincipleonwhichaclutchworksis
friction.Whentworevolvingfrictionsurfacesare
broughtintocontactandpressed,thentheyare
unitedandstartrevolveatsamespeedduetofriction
forcebetweenthem.Thisisthebasicprincipleof
clutch.
Thefrictionbetweenthesetwosurfacesdependson
theareaofsurface,pressureapplieduponthemand
thefrictionmaterialbetweenthem.

4. Thedrivingmemberofaclutchistheflywheel
mountedontheenginecrankshaftandthedriven
memberispressureplatemountedonthe
transmissionshaft.
Somefrictionplates,sometimesknownasclutch
platesarekeptbetweenthesetwomembers.This
wholeassemblyisknownastheclutch.

5. Anautomobileclutchhasfollowingfunction:
1.Itcanbedisengaged.Thisallowsenginecranking
andpermitstheenginetorunwithoutdelivering
powertothetransmission.
2.Whiledisengaging,itpermitsthedrivertoshift
thetransmissionintovariousgearaccordingto
operatingcondition.

6. 3.Whileengaging,theclutchslipsmomentarily.this
providessmoothengagementandlessenstheshock
ongears,shaftandotherpartsofautomobile.
4.Whileengaging,theclutchtransmitsthepowerto
thewheelwithoutslipping,inidealcondition.

7. 1.Drivingmember:
Itisthememberwhichisdirectlyconnectedtothe
crankshaft.Thedrivingmemberconsistsofacover
whichcarriesthepressureplate(drivingdisc),the
pressurespringsandthereleasinglever.Thisentire
assemblyisboltedontheflywheelandrotateswith
engineallthetime.Theflywheelandthepressure
plategripthedrivenmemberbetweenthemunder
theactionofthepressurespring.

8. 2.Drivenmember:
Thedrivenmemberconsistsofaplatewhichisfree
toslidelengthwiseonthesplinesoftheclutchshaft
butwhichdrivestheshaftthroughthosesplines.This
plateisknownasfrictionplate.Theclutchhousing
alsoincludesinthedrivenmember.
3.Operatingmember:
Theoperatingmemberconnectsthedrivertothis
wholeassembly.Itconsistthefootpedal,thelinkage,
thereleaseleverandspringsnecessarytoensure
properoperationoftheclutch.

12. 1.FrictionClutch
Cone clutch
Single plate clutch
Multi-plate cutch
Semi-centrifugal clutch
Centrifugal clutch
2.Fluidflywheel
Fluidcoupling
Torqueconverter.

14. 1.ConeClutch
Aconeclutch“oldestofall”isatypeof
clutchsysteminwhichtwomatingmembersknown
asthemalememberandthefemalemember
designedinshapeofconesareused,duetothe
matingofthesetwomembersfrictionalforcedueto
thefrictionalcontactbetweenthemisgenerated
resultsintorqueorpower.
Theengagementanddisengagementofthemaleand
femalememberoftheconeclutchiscontrolledbythe
clutchpedal.

15. 1.FemaleCone-Itisthepartofaconewhichis
connectedtotheflywheeloftheengineandalso
rotateswithit,thisconeishavinginnercutting
coneshapedgrooveoverwhichthemalecone
interlocksandmakefrictionalcontactwithitin
ordertoengagethedrive.
2.MaleCone-Itisthepartofaconeclutchwhichis
connectedtothetransmissionshaftandis
machinedintheshapeofasolidconeoverwhich
frictionalmaterialisattached.

16. 3.Spring–Normalthrustspringlocatedbehindthe
maleconeisusedforengagementand
disengagementoftheclutch.
4.Shafts-Thefemaleconewhichisdirectlyattached
totheflywheelismountedoverasolidshaft.
5.Sleeves-Sleeveshavinginnersplinesattachedto
themaleconemountedoverthesplinedshaftis
usedforthetoandfromotionofthemalecone.
6.Pedal–Aclutchpedaloperatedbythedriveris
usedforinputregardingtheengagementandthe
disengagementoftheclutch.

19. 1.Lesswearandtearcomparetopositive
displacementclutch.
2.Itissilentinoperation.
3.Thenormalforceactingonthecontactsurfaceis
largerthantheaxialforcegeneratedbythesprings.
4.Comparativelyhighertorquecanbetransmitted
thansamesizeofplateclutch.

20. 1.Operationoftheclutchishighlydependedonthe
coneangle.Iftheconeangleissmallerthan20
degree,itbecomesdifficulttodisengagetheclutch.
2.Frequentmaintenancerequiredbecausethesmall
amountofwearontheconesurfaceresultsina
considerableamountoftheaxialmovementofthe
innercone.

22. 2.SinglePlateClutch
Itisatypeoffrictionclutchinwhichpoweris
transmittedbymeansoffrictionbetweenthecontact
surfaceusuallycalledclutchplates.
Asnamesuggestathisclutchconsistsofonlyone
clutchplatewithbothsidefrictionlining(frictional
surface).
ThesesurfaceshavehighCoefficientoffriction.Single
plateclutchalsocalleddryclutchbecausenolubricant
isusedascoolant.

23. 1.Clutchplate:
Insingleplateclutchonlyoneclutchplateisused.
Clutchplateismaincomponentofclutches.Itisthin
disctypemetallicplatehavingbothsidefrictional
surfaces.Frictionalsurfacesonplatemustbeofsuch
materialtoprovidefrictionfortransmittingtorque
withoutsleeping.Thecoefficientoffrictionof
contactsurfacesshouldbehighforproperconnection
withoutslipping.Clutchplateisassembledin
betweenflywheelandpressureplate.

24. 2.Pressureplate:
Thepressureplatewhichisgenerallymadeupofcast
iron.Ithelpsinapplyingpressureonclutchplatesto
maintainthepropercontactbetweenthesurfacesof
flywheelandclutchplatebymeansofspringwhich
areattachedtoit.
3.Springs:
Springsareusedtomaintainthepressureonpressure
plateforproperconnectionbetweenclutchplateand
flywheelandpreventtheslippingofcontactsurfaces.

28. 4.Flywheel:
Flywheelisattachedtoengineoutputanditsother
sidecomesincontactwithclutchplatewhenpressure
isappliedbythepressureplate.
Operatingmechanism:
Thisincludesfootpedal,linkage,bearingandlever
etc.Allthesecomponentsareconnectedina
sequence.Footpedalislocatedinsidetheautomobiles;
alevermechanismisattachedwithfootpedalwhich
transmitthemotionfrompedaltospringbymeans
ofthrustbearings.

29. Aleverisattachedtothepaddlewhichisresponsible
fortheforcetransmissionfromthepaddle.
Whenpedalispressedspringiscompressedand
engineisfreetomovewithoutanyload.
Leverisattachedinsuchamannerwhenwepress
theclutchpaddlethrustbearingmovesforwardand
pressureplatemovesbackwardoritmovesawayfrom
theflywheel;duetothistheconnectionbetweenthe
clutchplateandflywheelreleasedandshaftsare
disengaged.

30. Thistimewecaneasilychangegearsincaseof
automobiles.Againifwewanttoengagetheshafts
justreleasetheclutchpaddle;thenspringsattached
tothepressureplatepushthepressureplateforward.

31. Theworkingofthesingleplateclutchissmoothi.e.
theengagementanddisengagementisverysmoothin
operation
Lessslipoccursinit;slipisoccursonlyatthetime
ofengagementafterengagementnoslipoccursand
thefunctioningbecomesverysmooth.
Powerlossesareveryless.
Lessheatgeneratesbecauseonlysingleplateisused.
Heatgenerationcreatesprobleminpower
transmissionandcandamagetheworkingparts.

32. Ithaslesstorquetransmittingcapacity.
Ithasbiggerinsizeevenfortransmittingless
torque.
Itrequireshighmaintenancebecausetheyaredry
clutchesanditisnecessarytopreventthemfrom
moistureoranyleakageoflubricant/oilin
machinery.
Singleplateclutcheshavehighwearandtearrate
andhavelesssmoothengagement.
Applications:
Theseareusedinlargesizeautomobileswhereradial
spaceisnotconstrainsuchastrucksandcars.

34. 3.MultiPlateClutch
Asnamesuggestathisclutchconsistsofonlyone
clutchplatewithbothsidefrictionlining(frictional
surface).Amulti-plateclutchisatypeofclutchthat
transmitsmorepowerfromtheenginetothe
transmissionshaftofanautomobilevehicleandalso,
makesupforthetorquelossduetoslippage.
Heavymachinery,commercialvehicles,special
purposemilitaryvehicles,racingcarsandbikesuse
thistypeofclutch.

35. Scootersandmotor-cyclesusemulti-plateclutches
duetolimitedspaceintheirgearboxes.
Multipleclutchesconsistofmorethanthreediscsor
platessothatitisabletoprovidemoretorqueoutput.

40. 1.SpringtypeMulti-PlateClutch
2.DiaphragmtypeMulti-PlateClutch
3.HydraulicOperatedorAutomaticTransmission
Multi-PlateClutch
1.SpringtypeMulti-PlateClutch:Inthistypeof
Multi-PlateClutch,acoverisboltedtotheflywheel.
Multipleclutchplateisfoundonthecover.Theouter
platesoftheclutchapplythrustontheinnerplates
withthehelpofclutchspringsorthrustspringsto
formadrive,therebyengagingtheplates.

41. Fortheclutchdisengagement,themechanism
withdrawstheendplatetocompressthespringsand
releasetheotherplates.Oldcarsandbikesusethis
typeofclutch.
2.DiaphragmtypeMulti-PlateClutch:Thistype
ofclutchconsistsofaspecialcrownshapedfinger
typespring,thatiswhythenamediaphragmtype.It
doesnotcomewiththrustspringsorclutches.
Duringengagementoftheclutch,thediaphragm
bearsagainsttheouterringandduring
disengagement,thereactionloadisbearbytheinner
ring.Modernbikesandcarsusethistypeofclutch.

42. 3.HydraulicOperatedorAutomaticTransmission
Clutch:Automatictransmissionvehiclesusethistype
ofclutch.Ahydraulicdevicecontaininghighly
compressedfluidoperatingwiththeacceleratedpedal
isattachedtothemulti-plateclutch.Theengagement
andthedisengagementoftheclutchplatesare
receivedbythehydraulicdevicewhichiscontrolled
withtheacceleratorpedal.

44. 4.SemiCentrifugalClutch
“SemiCentrifugalClutchesusedinhighpowered
enginesandracingcarengineswhereclutch
disengagementsrequireappreciableandtiresome
driverseffort.”Thepowertransmittedwithpartlyby
clutchspringsandremainingbythecentrifugalaction
ofanextraweightprovidedinthesystem.
Theclutchspringstransmitpoweratlowengine
speedandthecentrifugalforcetransmitpowerat
higherenginespeed.

45. Besidesclutch,pressureplateandsplinesshaftit
mainlyconsistsof:
1.Compressionspring(3numbers)
2.Weightedlevers(3numbers)
3.EngineShaft
4.Flywheel
5.ClutchShaft

46. Whentheengineatlowspeedthespringkeepsthe
clutchengagedtotransmitpower,theweighted
leversdonothaveanypressureonthepressureplate.
Whenengineathighspeedtheweightsflyoffand
leversexertpressureonthepressureplatewhich
keepstheclutchfirmlyengagedtotransmithigh
torque.
Thusinsteadofhavingmorestiffspringsfor
keepingtheclutchengagedfirmlyathighspeeds,
theyarelessstiffbecauseofcentrifugalforcesof

47. weightedlevers,sothatthedrivermaynotgetany
straininoperatingtheclutch.
whentheenginespeeddecreases,theweightsfalland
theweightedleversdonotexertanypressureonthe
pressureplateandonlyspringpressureisexertedon
thepressureplatetokeeptheclutchengaged.

49. Advantages
1.Clutchoperationisveryeasy.
2.Lessstiffclutchspringsareusedastheyoperate
onlyatlowenginespeeds.
Disadvantages
1.Springshavetransmittedthetorqueatlowerengine
speedsonly.
2.Centrifugalforcesworkonlyathigherenginespeedto
transmittorque.

50. SemiCentrifugalClutchisusedinVauxhallcar(foreign
car).

52. 5.CentrifugalClutch
“CentrifugalClutchusescentrifugalforceinsteadof
springforce.Thisclutchisalwaysinengagedposition.”
anditdoesnothaveaclutchpedaltooperateit.
Centrifugalclutchisautomaticallyoperatedwith
enginespeed.Thevehiclecanbestoppedingear
withoutstalling(stoprunning)theengine.Andalsothe
gearcanbestartedinanygearbypressingthe
acceleratorpedal.

53. Acentrifugalclutchworksoncentrifugalforce.One
sideofclutchconnectedtotheenginecrankshaftand
othersideconnectedtogearboxshaft,chain,orbelt.
AsengineR.P.M.(RevolutionsPerMinute)increases,
weightedarmsintheclutchswingoutwardandforce
theclutchtoengageposition.
ThemostcommonCentrifugalClutcheshavefriction
padsorshoesradiallymountedthatengagetheinside
oftherimofthehousing.

54. Onthecentershaft(Drivingorinputshaft)thereare
anassortedamountofextensionsprings,which
connecttoaclutchshoe.
Whenthecentershaft(Drivingshaft)spinsfast
enough,thespringsextendcausingtheclutchshoes
toengagethefrictionface.
Itcanbecomparedtoadrumbrakeinreverseorder.
Theweightedarmsforcethesediskstogetherand
engagetheclutchandpowertransmitted.

55. WhentheengineshaftreachesacertainRPM
(RevolutionsPerMinute),theclutchactivates,
workingalmostlikeacontinuouslyvariable
transmission.
AstheloadincreasestheR.P.M.dropsthereby
disengagingtheclutchandlettingtheRPMriseagain
andreengagingtheclutch.

58. Advantages
1.CentrifugalClutchhaslessmaintenance.
2.Itisnotexpensive.
3.Itdoesnotneedclutchpedalbecauseit’sautomatic.
4.Ithelpstopreventtheenginefromstalling(stop
running).
Disadvantages
1.Duetoslippingandfriction,Thereisalossofpower.
2.Itcausesoverheatingproblems.
3.Itsengagementanddisengagementsdependuponthe
speedofthedrivingshaft.

59. 1.Thecentrifugalclutchismainlyusedinmopedsand
go-karts.
2.Itisalsousedinminibikes,chainsaw,andlawn
mowersetc.
3.ItisusedinboatsandPara-motorstokeepthe
enginerunningduringstalling(stoprunning)and
disengageloadsduringstartingandidling.