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AUTOMATIC TRANSMISSIONAUTOMATIC TRANSMISSIONAUTOMATIC TRANSMISSIONAUTOMATIC TRANSMISSION
Presented By, Guided By,Presented By, Guided By,Muhammed RiyasMuhammed Riyas Gopinathan.VGopinathan.VSS77MMBB Asst:ProfAsst:ProfNO:103NO:103 Dept of Mechanical EnggDept of Mechanical Engg
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IntroductionIntroduction
Device which changes gear ratios automaticallyDevice which changes gear ratios automatically Deliver maximum efficiencyDeliver maximum efficiency
Difference between automatic and manual transmissionDifference between automatic and manual transmission Easier to drive because they do not have a clutch pedal orEasier to drive because they do not have a clutch pedal or
gearshift levergearshift lever
There are two type of automatic transmissionsThere are two type of automatic transmissions
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CLASSIFICATIONCLASSIFICATION
AUTOMATICAUTOMATICTRANSMISSIONSTRANSMISSIONSUSINGPLANETARYUSINGPLANETARYGEARSGEARS
CONTINUOUSLYVARIABLECONTINUOUSLYVARIABLETRANSMISSION(CVT)TRANSMISSION(CVT)
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AUTOMATIC TRANSMISSIONSAUTOMATIC TRANSMISSIONSUSING PLANETARY GEARSUSING PLANETARY GEARS
ComponentsComponents
PLANETARY GEARPLANETARY GEARSYSTEMSYSTEM
TORQUE CONVERTERTORQUE CONVERTER HYDRAULIC SYSTEMHYDRAULIC SYSTEM
GOVERNORGOVERNOR COMPUTERCOMPUTERCONTROLSCONTROLS
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1. Sun gear 2. Planet gear 3. Ring gear 4.Planetary carrier
PLANETARYGEARSYSTEM
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PLANETARYGEARSYSTEM(SIDEVIEW)
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HOWPLANETARYGEARSWORK
Input Output Stationary Calculation Gear Ratio
A Sun (S) Planet Carrier (C) Ring (R) 1 + R/S 3.4:1
B Planet Carrier (C) Ring (R) Sun (S) 1 / (1 + S/R) 0.71:1
C Sun (S) Ring (R) Planet Carrier (C) -R/S -2.4:1
Gear Input Output Fixed Gear Ratio
1st 30-tooth sun 72-tooth ring Planet carrier 2.4:1
2nd
30-tooth sun Planet carrier 36-tooth sun 2.2:1
Planet carrier 72-tooth ring 36-tooth sun 0.67:1
Total 2nd 1.47:1
3rd30- and 36-tooth
suns72-tooth ring 1.0:1
OD Planet carrier 72-tooth ring 36-tooth sun 0.67:1
Reverse 36-tooth sun 72-tooth ring Planet carrier -2.0:1
Power transfer can only take place when one of the members is
held at rest or if two of the members are locked.
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TORQUE CONVERTOR
takes the place of the clutchfound on standard shift vehicles
large doughnut shaped device that is mounted
between the engine and the transmission it uses oil or transmission fluid to transmit power three internal elements that work together
to transmit power to the transmission.
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TORQUE CONVERTOR
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THEHYDRAULICSYSTEM
complex maze of passages and tubes that sends transmissionfluid under under pressure to all parts of the transmissionand torque converter.
Transmission fluid serves in shift control, general lubricationand transmission cooling.
Keeps the transmission at normal operating temperature
OIL PUMP VALVE BODY SHIFT VALVES BANDS
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Gear pumpGear pump
OilPumpOilPump
Produce all the oil pressure that isrequired in the transmission
The oil is then sent, underpressure to the pressure regulator,the valve body and the rest of thecomponents, as required.
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Valve BodyValve Body
The brain of the automatictransmission
Contains a maze of channels
and passages that directhydraulic fluid to thenumerous valves
These valves activate the
appropriate clutch pack orband servo to smoothly shiftto the appropriate gear foreach driving situation.
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Shift Valves
Supply hydraulic pressure tothe clutches and bands toengage each gear
Determines when to shift fromone gear to the next
The 1 to 2 shift valvesdetermines when to shift fromfirst to second gear.
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BandBand
A band is a steel strap with
friction material bonded to the
inside surface.
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GOVERNERGOVERNER
provides the inputs that tell theprovides the inputs that tell thetransmission when to shifttransmission when to shift
connected to the output shaftconnected to the output shaft
and regulates hydraulic pressureand regulates hydraulic pressurebased on vehicle speedbased on vehicle speed
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COMPUTERCONTROLLSCOMPUTERCONTROLLS
Detect such things as throttle position, vehicle speed,Detect such things as throttle position, vehicle speed,engine speed, engine load,etc. to control exactengine speed, engine load,etc. to control exact shiftshift
pointspoints
Downshift automatically when going downhill, toDownshift automatically when going downhill, tocontrol speed and reduce wear on the brakes.control speed and reduce wear on the brakes.
Up shift when braking on a slippery surface to reduceUp shift when braking on a slippery surface to reducethe braking torque applied by the engine.the braking torque applied by the engine.
Inhibit the Up shift when going into a turn on aInhibit the Up shift when going into a turn on awinding road.winding road.
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CONCLUSIONCONCLUSION
Automatic transmissions contain mechanical systems,hydraulic systems, electrical systems and computer controls,all working together in perfect harmony
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THANK YOUTHANK YOU