welcomeanun-150830200823-lva1-app6892

8/19/2019 welcomeanun-150830200823-lva1-app6892

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WELCOME


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CLUTCH

PRESENTATIONBY ONKAR NATH1215040037


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WHY DO WE NEED CLUTCH

Clutches are useful in devices with two rotating

shafts. In these devices, one of the shafts is

typically driven by a motor or pulley, and the other

shaft is driving another device. In a drill, forinstance, one shaft is driven by a motor and the

other is driving a drill chuck. The clutch connects

the two shafts so that they can either be locked

together and spin at the same speed, or bedecoupled and spin at different speeds.


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• In a car, you need a clutch because the engine

spins all the time and the car wheels don't. In

order for a car to stop without killing the engine,

the wheels need to be disconnected from the

engine somehow. The clutch allows us tosmoothly engage a spinning engine to a non-

spinning transmission by controlling the slippage

between them. To understand how a clutch

works, it helps to know a little bit about friction.


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CLUTCH INTRODUCTION

• A clutc is a mechanical device that provides forthe transmission of power (and therefore usuallymotion) from one component (the drivingmember) to another (the driven member) whenengaged, but can be disengaged.

• Clutches are used whenever the transmission ofpower or motion must be controlled either inamount or over time (e.g., electric screwdrivers

limit how much torque is transmitted through useof a clutch; clutches control whether automobilestransmit engine power to the wheels).


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• n the simplest application, clutches connect

and disconnect two rotating shafts (driveshafts or line shafts). n these devices, oneshaft is typically attached to a motor or otherpower unit (the driving member) while the

other shaft (the driven member) providesoutput power for wor!. "hile typically themotions involved are rotary, linear clutches arealso possible

• Clutch is used to engage or disengage theengine to the transmission or gear bo#.


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• "hen the clutch is in engaged position, theengine power or rotary motion of enginecran!shaft is transmitted to gear bo# andthen to wheels.

"hen clutch is disengaged, the enginepower does not reach to gear bo# (and towheels) although engine is running.Clutch is also used to allow shifting or

changing of gears when vehicle is running.$or shifting gears, clutch is %rstdisengaged then gear is shifted and thenclutch is engaged. Clutch has to be

disengaged to stop the vehicle and also at


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PRINCIPLE O! CLUTCH

• It operates on the principle of friction. hen two

surfaces are brought in contact and are held

against each other due to friction between them,

they can be used to transmit power. If one isrotated, then other also rotates. !ne surface is

connected to engine and other to the

transmission system of automobile. Thus, clutch

is nothing but a combination of two frictionsurfaces.


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MAIN PARTS O! CLUTCH

• t consists of

• (a) a driving member,

• (b) a driven member, and

• (c) an operating member.

• &riving member has a 'ywheel which is mounted on theengine cran!shaft. A disc is bolted to 'ywheel which is!nown as pressure plate or driving disc.

• he driven member is a disc called clutch plate. his plate

can slide freely to and fro on the clutch shaft.

• he operating member consists of a pedal or lever whichcan be pressed to disengaged the driving and driven plate.


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TYPES O! CLUTCH

ome types of clutches used in vehicles are given below *

• (a) !"#ct#$% Clutc & t may be (i) single plate clutch, (ii)multi+plate clutch, or (iii) cone clutch. ulti+plate clutchcan be either wet or dry. A wet clutch is operated in an

oil batch whereas a dry clutch does not use oil.(b) Centrifugal clutch.

(c) emi+centrifugal clutch.

(d) -ydraulic clutch.

(e) ositive clutch.(f) /acuum clutch.

(g) 0lectromagnetic clutch.


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!RICTION CLUTCH

• he vast ma1ority of clutches ultimatelyrely on frictional forces for their operation.

he purpose of friction clutches is to

connect a moving member to another thatis moving at a di2erent speed orstationary, often to synchroni3e thespeeds, and4or to transmit power. 5sually,

as little slippage (di2erence in speeds) aspossible between the two members isdesired.


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TYPES O! !RICTION CLUTCH

. single plate clutch

. multi+plate clutch or (iii) cone clutch.ulti+plate clutch can be either wetor dry. A wet clutch is operated in an oil

batch whereas a dry clutch does not useoil.


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SIN'LE PLATE CLUTCH

• A single plate is commonly used in carsand light vehicles. t has only one clutchplate which is mounted on the splines ofthe clutch shaft. A 'ywheel is mounted on

the cran!shaft of the engine. A pressureplate is connected to the 'ywheel throughthe bolts and clutch springs. t is free toslide on the clutch shaft with the

movement of clutch pedal. "hen clutch isin engaged position, the clutch plateremains gripped between 'ywheel andpressure plate. $riction linings are providedon both the sides of clutch plate. 6n one


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• plate. &ue to friction on both sides, theclutch plate revolves with engine 'ywheel.

herefore, clutch transmits engine powerto clutch shaft. Clutch shaft is connected totransmission (or gear bo#) of automobile.

hus, clutch transmits power from engine

to transmission system which internrotates wheels of engine.

• "hen the clutch plate is to be disengaged,the clutch pedal is pressed. 7ecause of thispressure plate moves bac! and clutchplate is disengaged from 'ywheel. hus,

clutch shaft stops rotating even if engine


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WORKIN' O! SIN'LE PLATECLUTCH

• "or!ing* he diagram shows the pressure plate pulled

bac! by the release levers against the compression

springs; so that the friction lining on the clutch plate

are free of wheel rotates without driving the clutch

plate and hence the shaft.

• "hen the pressure of the thrust race is released the

compression springs are free to move the pressure

plate to the left bringing it in contact with the clutch

plate.


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• he pressure plate moves to the left, sliding theclutch

plate on its splined hub, along the driven shaft until

the friction touches the 'ywheel .

• he compression springs now cause the lining to begripped between the pressure plate and the 'ywheel

and pressure plate causes the clutch plate torevolve,

tuning the driven shaft.


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W(t #) *ult#+l(%, clutc

• A *ult#+l, +l(t, clutc is a type ofclutch system where multiple driven anddrive plates are used in order to ma!e up

for torque loss due to slippage. hisslippage is usually caused by a 'uid thatthe plates are immersed in for cooling,cleaning and lubrication. his type of

clutch system is commonly referred to as awet clutch system. he type ofarrangement is what is found in theautomatic transmission in your car. his

clutch system allows gears to be shifted up


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Mult# Pl(t, Clutc

• A multi+plate clutch has more than one driven plate.Although this type of clutch has been widely used oncars up to about 89:, the several advantages of thesingle+plate clutch, speci%cally its ability to

completely disengage the drive has caused a veryrare use of a multi+plate unit as a main transmissionclutch installed between the engine and gear bo#.-owever, a multi+plate type of clutch %nds a use inautomatic gearbo#es. n these gearbo#es, a number

of clutches hold the various gear elements, and as theclutch diameter in these units is limited, a multi+plateclutch is suitable.


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MULTIPLATE CLUTCH

• ulti+plate clutch consists of more thanone clutch plates contrary to single plateclutch which consists of only one plate.

$riction surfaces are made in case of multi+plate clutch. &ue to increased number offriction surfaces, a multi+plate clutch cantransmit large torque. herefore, it is used

in racing cars and heavy motor vehicleswitch have high engine power. he clutchplates are alternatively %tted with engineshaft and the shaft of gear bo#. -e plates

are %rmly held by the force of coil springs


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• 6ne plate slides in the grooves on the 'ywheel andthe ne#t plate slides on spines provided onpressure plate. hus, each alternate plate slides ingrooves on the 'ywheel and the other on splines ofpressure plate. f we ta!e two consecutive plates,then one has inner and other has outer splines.

• "hen the clutch pedal is pressed, the pressureplate moves bac! against the force of coil spring,hen the clutch plates are disengaged and engine'ywheel and gear bo# are decoupled. -owever,

when clutch pedal is not pressed the clutch remainin engaged position and the power can betransmitted from engine 'ywheel to the gear bo#.


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AD-ANTA'E

• he main purpose for a wet multi+plate clutch isincreased power transmission capability in a compactsi3e. As a side e2ect, multi+plate wet clutchesgenerally have very good progressive engagement


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Mult#.+l(t, S+"#%/ t+, clutc

• llustrates the layout of a multi+platespring type clutch, %tted on early motorcars. A cover, bolted to the 'ywheel,

engages by means of slots with a series oflugs on the outer plates. hese steel platesmay be plain or %tted with cor! or frictionmaterial inserts and act on inner plates,

splined to a hub. hrust springs push theplates together to form a drive.


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• $or the clutch disengagement, the endplate is withdrawn to compress the springsand release the other plates. n thisarrangement it is di>cult to ensure thedisengagement of all plates. o overcome

this problem the plates are either dished or%tted with small springs to push the platesapart.?enerally wet type clutch is used in

automatic gearbo#es, and is operated by apiston governed by hydraulic pressure.intered bron3e plates of partially fusingpowdered bron3e or compressed paper are

used in many designs. he porous surface

u ( , (+ "(/* +,


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u . ( , (+ "(/* +,Clutc

• hese clutches basically have drive and

driven plates. he drive plates are notallowed to rotate independently by usinginterloc!ing lugs and slots, which do notpermit relative rotational spin, but a#ialmovement. he driven plates are mountedon the internally splined hubs, whichsplines on the gearbo# spigot shaft ($ig.

@.8B).A dished annular disc forms the diaphragmspring, the inner portion of which is radiallyslotted and the outer ends are enlarged

with a circular hole to prevent stress


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• &uring operation, due to engagement anddisengagement of the clutch, thediaphragm cone angle changescontinuously as wear occurs. n order toaccommodate the change, the diaphragm

pivots and rolls about the fulcrum rings.&uring engagement of the clutch thediaphragm bears against the outer ring,and during disengagement the reaction

load is ta!en by the inner ring. As thefriction linings wear, the spring diaphragmbecomes more dished so that a larger a#ialclamping load is applied initially. As the

linings wear increases the distance

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