Clutches
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Transcript of Clutches
12/2001 1
Presented By –
Clutches A clutch is a mechanical device that provides for
the transmission of power (and therefore usually motion) from one component (the driving member) to another (the driven member) when engaged, but can be disengaged.
In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). In these devices, one shaft is typically attached to a motor or other power unit (the driving member) while the other shaft (the driven member) provides output power for work. While typically the motions involved are rotary, linear clutches are also possible.
In a torque-controlled drill, for instance, one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so that they may be locked together and spin at the same speed (engaged), locked together but spinning at different speeds (slipping), or unlocked and spinning at different speeds (disengaged).
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Location of Clutches Rear wheel drive
Front engine Rear engine Mid engine
Front wheel drive
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Construction Of Clutches
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Coil spring pressure plate (cover and pressure plate)
44-3 Construction of the Clutch
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Splines to input shaftOf transmission
Clutch Disk orFriction Disk
Pilot Bushing or bearing
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Construction of the Clutch
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Flywheel boltsto crankshaft
Pressure plate & coverbolt to flywheel
If there is a chance you will be reusingpressure plate, make alignment marksto flywheel to maintain proper balanceBEFORE removal
When unbolting pressure plate from theflywheel, remove bolts evenly as not tobend the cover. REMEMBER, this is under high spring pressure.
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Bolted to Crank
(friction disk) splined to transmissionInput shaft
(throw-out bearingT/O bearing) allowsto push on rotatingclutch fingers
Bolted to flywheel - Applies the spring force to clamp thefriction disk to the flywheel
(clutch fork) pushesT/O bearing to releaserotating clutch
Pilot bushing or bearing in centerof flywheel or crankshaft, supportsthe end of input shaft
Pressure Plate
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PivotsT/O bearing
Moves pressurePlate right
Releases friction diskfrom flywheel
Clutch terms Clutch disengaged
Clutch pedal is in or down Clutch engaged
Clutch pedal is out or up
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What would it mean if someone said the clutch pedalIs engaged?Make sure you know if you are talking about the clutch or the clutch pedal !!!
Throw out Bearing (release bearing)
Slides on transmission input shaft bearing retainer
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Clutches
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READ ON
Slipping clutch
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Clutch Linkage
Can be very complicatedHave the right amount of
movement and direction without too much pedal pressure
WearMotor mountsSpring to pull T/O bearing
awayHas to be lubricated
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Clutch fork
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T/O bearinghooks here
Fulcrum point
Hydraulic clutch Uses master cylinder and slave cylinder Uses brake fluid Must be bleed
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Hydraulic clutch No complicated
linkage Can easily control
mechanical advantage with piston sizes
Self lubricating No motor mount
problems
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Service just like you would hydraulicbrakes
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Slave cylinder
Some are adjustablefor free-play and
some not
Cable clutch
No complicated linkage
Flexibility No motor mount
problems
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Friction disks
Often made of asbestos
Must be put in only one wayUsually markedClutch won’t
release if wrong
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Friction disks Cushion springs
Waved metal between clutch half'sDampen clutch engagement
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Friction disks Torsional springs
Can be spring or rubberDampen power impulses from crankshaft
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Torsional Springs
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Has pins to limit amount of twist.Springs try to keep it centered between pins.
Springs sometimes get weak and start rattling or fall out
Clutch disks
12/2001 24
Friction material isn’t very thick.Minimum thickness around .012”
Types of Clutches (pressure plates)
Coil spring9 spring12 spring
3 fingers for T/O bearing to push on
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Diaphragm-Spring Clutches
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Diaphragm-Spring Clutches
Centrifugal Clutch The faster the RPM, the harder the
clutch disk is squeezed
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Multi-plate Clutch
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Conical Clutch
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Clutch Safety Switch Prevents from cranking with clutch
engaged Some standard transmissions won’t let
you take the key out and lock the steering column with out the transmission in reversePrevents steering lock while moving forward
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Checking pressure plate for warpage
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Clutch Disk Replacement Very wise to:
Have flywheel surfaced (even with no run-out or hot spots)
Replace pilot bushing or bearingReplace T/O bearingReplace pressure plate (cover, plate
springs)
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Clutch Disk Replacement Very wise to inspect & replace as
necessary:Clutch fork & pivotInput shaft bearing retainer on transmission
(where T/O bearing slides)Linkage, cable or hydraulic componentsMotor mountsFlywheel ring gear
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Universal clutch alignment tool Select end that fits tight in pilot bushing
or bearing
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Universal clutch alignment tool
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Universal clutch alignment tool
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Clutch Alignment tools (pilot shaft)
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