Clutches- A.J.More

Machine Elements II - Rini D - TM FT UGMMachine Elements II - Rini D - TM FT UGM
BASIC MECHANICALBASIC MECHANICAL
ENGINEERINGENGINEERING
CLUTCHESCLUTCHES

INTRODUCTIONINTRODUCTION
 THE CLUTCHES ARE MOUNTED BETWEEN THE DRIVINGTHE CLUTCHES ARE MOUNTED BETWEEN THE DRIVING
SHAFT AND THE DRIVEN SHAFT.SHAFT AND THE DRIVEN SHAFT.
 THE FLOW OF MECHANICAL POWER FROM THE PRIMETHE FLOW OF MECHANICAL POWER FROM THE PRIME
MOVER TO THE DRIVEN MACHINE IS CONTROLLED BYMOVER TO THE DRIVEN MACHINE IS CONTROLLED BY
MEANS OF CLUTCHES.MEANS OF CLUTCHES.
 IN AUTOMOBILES, IN ORDER TO CHANGE THE GEARSIN AUTOMOBILES, IN ORDER TO CHANGE THE GEARS
OR TO TEMPORARILY STOP THE VEHICLE THEOR TO TEMPORARILY STOP THE VEHICLE THE
REQUIREMENT IS THAT THE DRIVEN SHAFT SHOULDREQUIREMENT IS THAT THE DRIVEN SHAFT SHOULD
STOP BUT THE ENGINE SHOULD CONTINUE TOSTOP BUT THE ENGINE SHOULD CONTINUE TO
RUN.THIS IS ACHIEVED BY MEANS OF CLUTCH,RUN.THIS IS ACHIEVED BY MEANS OF CLUTCH,
MOUNTED BETWEEN THE ENGINE AND THE GEAR BOX,MOUNTED BETWEEN THE ENGINE AND THE GEAR BOX,
WHICH IS OPERATED BY LEVER.WHICH IS OPERATED BY LEVER.

ClutchesClutches

DEFINITIONDEFINITION
 CLUCHES IS A MECHANICALCLUCHES IS A MECHANICAL
DEVICE WHICH IS USED TODEVICE WHICH IS USED TO
CONNECT OR DISCONNECT THECONNECT OR DISCONNECT THE
DRIVING SHAFT FROM THEDRIVING SHAFT FROM THE
DRIVEN SHAFT AT THE WILL OFDRIVEN SHAFT AT THE WILL OF
THE OPERATOR.THE OPERATOR.

Basic purposeBasic purpose
 Used to disengage engine fromUsed to disengage engine from
input shaftinput shaft
 Clutch is a mechanism whichClutch is a mechanism which
enables the rotary motion of oneenables the rotary motion of one
shaft to be transmitted, whenshaft to be transmitted, when
desired, to a second shaft the axisdesired, to a second shaft the axis
of which is coincident with that ofof which is coincident with that of
the first.the first.

Clutch materialsClutch materials
 Materials for the structural parts of clutches: typicallyMaterials for the structural parts of clutches: typically
made of gray cast iron or steel.made of gray cast iron or steel.
 The friction surfaces are usually lined with materialThe friction surfaces are usually lined with material
having a good coefficient of friction and sufficienthaving a good coefficient of friction and sufficient
compressive strength and temperature resistance:compressive strength and temperature resistance:
asbestos fiber, but no longer used in many applicationsasbestos fiber, but no longer used in many applications
because of its danger as a carcinogen.because of its danger as a carcinogen.
 Linings may be molded, woven, sintered or of solidLinings may be molded, woven, sintered or of solid
material.material.
 Brass or zinc chips are sometimes added to improveBrass or zinc chips are sometimes added to improve
heat conduction and wear resistance.heat conduction and wear resistance.
 metals provide high temperature resistance andmetals provide high temperature resistance and
compressive strength than molded or woven materials.compressive strength than molded or woven materials.

CLASSIFICATION OF CLUTCHESCLASSIFICATION OF CLUTCHES
CLUTCHES
FRICTION
CLUTCHES
POSITIVE
CLUTCHES
PLATE OR DISK
CLUTCHES
CONE
CLUTCHES
SINGLE PLATE
CLUTCHES
MULTI-PLATE
CLUTCHES

Positive clutchesPositive clutches
Positive clutchesPositive clutches
Transmit power from the driving shaft to the driven shaft byTransmit power from the driving shaft to the driven shaft by
means of jaws or teeth.means of jaws or teeth.

POSITIVE CLUTCHESPOSITIVE CLUTCHES
 THE POSITIVE CLUTCHES ARETHE POSITIVE CLUTCHES ARE
USED WHEN THE POSITIVE DRIVEUSED WHEN THE POSITIVE DRIVE
REQUIREDREQUIRED
 JAW CLUTCH IS A TYPE OFJAW CLUTCH IS A TYPE OF
POSITIVE CLUTCHPOSITIVE CLUTCH

JAW CLUTCHJAW CLUTCH
 IT MAINLY OF TWO TYPESIT MAINLY OF TWO TYPES
 1) SQUARE SHAPED1) SQUARE SHAPED
 2) GEAR TOOTH SHAPED OR2) GEAR TOOTH SHAPED OR
SPIRAL SHAPEDSPIRAL SHAPED
THE JAW CLUTCH CONSIST OF TWOTHE JAW CLUTCH CONSIST OF TWO
VALVES, ONE IS FIXED TO DRIVINGVALVES, ONE IS FIXED TO DRIVING
SHAFT BY KEY AND ANOTHER ISSHAFT BY KEY AND ANOTHER IS
FREE TO SLIDE.FREE TO SLIDE.

ADVANTAGES OF POSITIVEADVANTAGES OF POSITIVE
CLUTCHESCLUTCHES
+ transmit large torque with no slip+ transmit large torque with no slip
+ develop very little heat, because they do+ develop very little heat, because they do
not depend upon frictionnot depend upon friction
+ generally lighter+ generally lighter
+ less costly than a friction clutches of+ less costly than a friction clutches of
similar torque capacitysimilar torque capacity

DISADVANTAGES OF POSITIVEDISADVANTAGES OF POSITIVE
CLUTCHESCLUTCHES
- Can not be engaged at high speeds,Can not be engaged at high speeds,
max 60 rpm for jaw clutches, and 300max 60 rpm for jaw clutches, and 300
rpm for toothed clutchesrpm for toothed clutches
- Shock accompanies engagement atShock accompanies engagement at
any speedany speed
- Require some relative motion in orderRequire some relative motion in order
to engage when both driving andto engage when both driving and
driven shafts are at restdriven shafts are at rest

FRICTION CLUTCHESFRICTION CLUTCHES
IN FRICTION CLUTCHES, TWO CONTACTING SURFACES AREIN FRICTION CLUTCHES, TWO CONTACTING SURFACES ARE
PRESSED AGAINST EACH OTHER.PRESSED AGAINST EACH OTHER.
THE FRICTIONAL FORCES BETWEEN THE CONTACTINGTHE FRICTIONAL FORCES BETWEEN THE CONTACTING
SURFACES IS RESPONSIBLE FORSURFACES IS RESPONSIBLE FOR
TRANSMITTING THE TORQUE.TRANSMITTING THE TORQUE.

SINGLE PLATESINGLE PLATE
CLUTCHESCLUTCHES

SINGLE PLATE CLUTCHSINGLE PLATE CLUTCH

A . J. More AISSMSIOITA . J. More AISSMSIOIT
ADVANTAGES OF FRICTIONALADVANTAGES OF FRICTIONAL
CLUTCHESCLUTCHES
+because they can slip relative to each+because they can slip relative to each
other, there is very little shock duringother, there is very little shock during
engagementengagement
+can be used for high speed+can be used for high speed
engagement applicationsengagement applications

DISADVANTAGES OFDISADVANTAGES OF
FRICTIONAL CLUTCHESFRICTIONAL CLUTCHES
- Do slipDo slip
- Do wear out (requiring replacement ofDo wear out (requiring replacement of
friction material)friction material)
- Heat is developed (might requireHeat is developed (might require
external cooling)external cooling)

CONE CLUTCHESCONE CLUTCHES
 THE CONE CLLUTCH CONSIST OFTHE CONE CLLUTCH CONSIST OF
A CUP KEYED TO THE DRIVINGA CUP KEYED TO THE DRIVING
SHAFT AND A CONE WITHSHAFT AND A CONE WITH
FRICTION LININING FREE TO SLIDEFRICTION LININING FREE TO SLIDE
AXIALLY ON THE SPLINED DRIVENAXIALLY ON THE SPLINED DRIVEN
SHAFT.SHAFT.

Cone clutchCone clutch

Cone clutchCone clutch
**

APPLICATION OFAPPLICATION OF
CLUTCHESCLUTCHES
 1)POSITIVE CLUTCHES-1)POSITIVE CLUTCHES-
 THEY ARE MAINLY USED IN SOME MACHINETHEY ARE MAINLY USED IN SOME MACHINE
TOOL, POWER PRESSES, PUNCHES etc.TOOL, POWER PRESSES, PUNCHES etc.
 2)FRICTION CLUTCHES-2)FRICTION CLUTCHES-
 THEY ARE USED IN TRANSMISSION SYSTEM.THEY ARE USED IN TRANSMISSION SYSTEM.
 IT TRANSMIT POWER PARTIALLY OR FULLY.IT TRANSMIT POWER PARTIALLY OR FULLY.
 IT MAINLY USED IN THE AUTOMOBILES.IT MAINLY USED IN THE AUTOMOBILES.
 CONE CLUTCHES ARE USED IN MACHINECONE CLUTCHES ARE USED IN MACHINE
TOOLS.TOOLS.

Clutches- A.J.More

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