Automatic Transmission 5

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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

Automatic Transmission 5

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