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AT05 power flow.pdf

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AT05 POWER FLOW
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Automatic Transmissions - Course 262 49 1. Given a clutch application chart, identify which holding devices are applied for each gear range 2. Given a clutch application chart and the powerflow model, identify the planetary gear components held for each gear range. 3. Describe the poer flow through the planetary gear sets for the following gear ranges a. First gear b. Second gear c. Third gear d. Reverse 5. Identify the gear selector positions which can be used to diagnose a fault in drive range. Section 5 POWER FLOW Lesson OjectivesSection 5 50 TOYOTA Technical Training Theplanetarygearsetcutawayandmodelshownbelowarefoundin ToyotaRepairManualsandNewCarFeaturesBooks.Themodelwill helpyouvisualizetheworkingsoftheholdingdevices,gearshaftsand planetarygearmembersforallgearpositions. TherearethreeshaftsintheSimpsonplanetary:theinputshaft,sun gear,andtheoutputshaft.Theinputshaftisdrivenfromtheturbine inthetorqueconverter.Itisconnectedtothefrontplanetaryringgear throughthemultiplateclutches.Thesungear,whichiscommonto boththefrontandrearplanetarygearsets,transferstorquefromthe frontplanetarysettotherearplanetaryset.Theoutputshaftis splinedtothecarrierofthefrontplanetarygearsetandtothering gearoftherearplanetaryandthenprovidesturningtorquetotherear wheelsortheoverdriveunit. Theoutputshaft,forthepurposesofpowerflow,referstotheoutputof theSimpsonplanetarygearset.Itmaybereferredtoasthe intermediateshaftinotherreferences.However,forourpurposesin discussingpowerflow,itwillbereferredtoastheoutputshaft. Planetary Gear Shafts The planetary gear set cutaway and model will help visualize the workings of holding devices, gear shafts, and planetary gear memebers Power Flow Model Gear Train ShaftsPOWER FLOW Automatic Transmissions - Course 262 51 Multiplateclutchesandbrakeswerediscussedindetailearlier,andin thecutawaymodelonthenextpage,wecanidentifytheirpositionand thecomponentstowhichtheyareconnected.Theholdingdevicesfor theSimpsonplanetarygearsetareidentifiedbelowwiththe componentstheycontrol: FUNCTION OF HOLDING DEVICES HOLDING DEVICE FUNCTION C 1 Forward Clutch Connects input shaft and front planetary ring gear. C 2 Direct Clutch Connects input shaft and front and rear planetary sun gear. B 1 2nd Coast Brake Prevents front and rear planetary sun gear from turning either clockwise or counterclockwise. B 2 2nd Brake Prevents outer race of F1i from turning either clockwise or counterclockwise, thus preventing front and rear planetary sun gear from turning counterclockwise. B 3 1 st and Reverse Brake Prevents rear planetary carrier from turning either clockwise or counterclockwise. F 1 No. 1 One-Way Clutch When B2 is operating, prevents front and rear planetary sun gear from turning counterclockwise. F 2 No. 2 One-Way Clutch Prevents rear planetary carrier from turning counterclockwise. Holding DevicesSection 5 52 TOYOTA Technical Training Thevalueofthismodelcanbeappreciatedwhenobservingthecontrol oftherearcarrierbythefirstandreversebrake(B3)andtheone-way clutchNo.2(F2)andcontrolofthesungearbythesecondbrake(B2) andtheone-wayclutchNo.1(Fl). Noticethatthefirstandreversebrake(B3)andone-wayclutchNo.2 (F2)bothholdtherearplanetarycarrier.Togethertheyprovideagreat holdingforceonthecarriertopreventitfromturningduringlowfirst gear. Notealsothatthesecondbrake(B2)andtheone-wayclutchNo.1(Fl) worktogethertoholdthesungear.Thesecondcoastbrake(B1)holds thesungeartoo.Thebenefittothisdesignwillbediscussedasthe powerflowiscoveredforeachgearposition. Planetary Holding Devices The first and reverse brake (B3) and one-way clutch No. 2 (F2) both hold the rear planetary carrier. The second brake (B2) and the one-way clutch No. 1 (F1) work together to hold the sun gear. The second coast brake (B1) holds the sun gear also.POWER FLOW Automatic Transmissions - Course 262 53 Thegearpositioninwhichtheseholdingdevicesareappliedcanbe foundontheclutchapplicationchartbelow.Thecharddescribeswhich holdingdevicesareappliedforagivengearposition.Ifyoufollowdown theleftsideofthecharttoshiftleverposition“D“and“first“gear position,theshadedboxestotherightofthegearpositionindicatethe holdingdevicesusedindrivefirstgear.Atthetopofthecolumnabove theshadedboxyouwillfindthecodedesignationfortheholding device.Forexample,indrivefirstgear,the forwardclutch (C1)andthe one-wayclutch No.2(F2)areappliedtoachievefirstgear. Shift Lever Position Gear Position C 1 C 2 B 1 B 2 B 3 F 1 F 2 P Parking R Reverse N Neutral 1st D 2nd 3rd 2 1st 2 2nd L 1st L 2nd* *Down-shift in Lrange, 2nd gear only—no up-shift Theclutchapplicationchartisyoukeytodiagnosis.Whena transmissionmalfunctionoccursandyourdiagnosisleadsyoutoa specificgear,youcanrefertothischarttopinpointthefaultyhonding device.Whentheholdingdeviceyoususpectisusedinanothergear position,youshouldbeabletodetectafailureinthatgearposition also. SegmentsofthisapplicationchartwillbeusedinthePowerFlow sectiontofamiliarizeyouwiththeiruse. Clutch Application Chart Clutch Application Chart for A130 TransSection 5 54 TOYOTA Technical Training Firstgearisuniquebecauseitusesboththefrontandrearplanetary gearsets.Theforwardclutch(C1)isappliedinallforwardgearsand drivestheringgearofthefrontplanetarygearset.Whentheringgear rotatesclockwise,itcausesthepinionstorotateclockwisesincethe sungearisnotheldtothecase.Thesungearrotatesina counterclockwisedirection.Thefrontplanetarycarrier,whichis connectedtotheoutputshaft,rotates,butmoreslowlythanthering gear;soforpracticalpurposes,itistheheldunit.Intherearplanetary gearset,thecarrierislockedtothecasebytheone-wayclutchNo.2 (F2).Turningtorqueistransferredtotherearplanetarybythesun gear,whichisturningcounterclockwise.Withthecarrierheld,the planetarygearsrotateinaclockwisedirectionandcausetherear planetaryringgeartoturnclockwise.Therearplanetaryringgearis connectedtotheoutputshaftandtransferstorquetothedrivewheels. D- or 2-Range First Gear First gear is unique because it uses both the front and rear planetary gear sets. Power Flow Through Simpson Planetary Gear Set D- or 2-Range First GearPOWER FLOW Automatic Transmissions - Course 262 55 Theforwardclutch(C1)connectstheinputshafttothefrontplanetary ringgear.Thesungearisdriveninacounterclockwisedirectioninfirst gear,andbysimplyapplyingthesecondbrake(B2),thesungearis stoppedbytheone-wayclutchNo.1(Fl)andheldtothecase.Whenthe sungearisheld,thefrontpiniongearsdrivenbytheringgearwalk aroundthesungearandthecarrierturnstheoutputshaft. D-Range Second Gear Second gear uses the front planetary gear set only. Theadvantageoftheone-wayclutchNo.2(F2)isintheautomatic upshiftanddownshift.Onlyonemultiplateclutchisappliedor releasedtoachieveanupshifttosecondgearordownshifttofirstgear. Noticehowthesecondbrake(B2)andtheone-wayclutch(Fl)bothhold thesungear.Thesecondbrakeholdstheouterraceoftheone-way clutchtothetransmissioncasewhenapplied.Theone-wayclutch preventsthesungearfromrotatingcounterclockwiseonlywhenthe secondbrakeisapplied. D-Range Second GearSection 5 56 TOYOTA Technical Training Theforwarddutch(C1)isappliedinallforwardgearsandconnectsthe inputshafttothefrontplanetaryringgearasitdoesinallforward gears.Thedirectclutch(C2)connectstheinputshafttothecommon sungear.Byapplyingboththedirectclutchandtheforwardclutch,we havelockedtheringgearandthesungeartoeachotherthroughthe directclutchdrumandtheinputsungeardrum.Whenevertwo membersoftheplanetarygearsetarelockedtogether,directdriveis theresult. Noticethatthesecondbrake(B2)isalsoappliedinthirdgear; however,sincetheone-wayclutchNo.1(Fl)doesnotholdthesungear intheclockwisedirection,thesecondbrakehasnoeffectinthirdgear. Sowhyisitappliedinthirdgear?Thereasonliesinadownshiftto secondgear.Allthatisnecessaryforadownshifttosecondgearisto releasethedirectandreverseclutch(C2).Theringgearprovidesinput torqueandthesungearisreleased.Thecarrierisconnectedtothe outputshaftandfinaldrivesotheoutputshafttendstoslowthe carrier.Thepiniongearsrotateclockwiseturningthesungear counterclockwiseuntilitisstoppedbytheone-wayclutchNo.1(Fl). Thecarrierprovidestheoutputtothefinaldrive. D-Range Third Gear Third gear uses the front planetary gear set only. D-Range Third GearPOWER FLOW Automatic Transmissions - Course 262 57 Directandreverseclutch(C2)isappliedinreverse,whichconnectsthe inputshafttothesungear.Thefirstandreversebrake(B3)isalso applied,lockingtherearcarriertothecase.Withthecarrierlockedin position,thesungearturningintheclockwisedirectioncausesthe planetarygearstorotatecounterclockwise.Theplanetarygearswill thendrivetheringgearandtheoutputshaftcounterclockwise. Uptothispointwehaveexaminedreversegearandthoseforwardgear positionswhichareautomatic.Thatis,withthegearselectorin D-positionallforwardgearsareupshiftedautomatically.Thegearscan alsobeselectedmanually,utilizingadditionalholdingdevices.This featurenotonlyprovidesadditionalcharacteristicstothedrivetrain butalsoallowsameansofdiagnosisforfaultsincertainholding devices. Reverse Range Reverse gear uses the rear planetary gear set only. Reverse RangeSection 5 58 TOYOTA Technical Training WhenthegearselectorisplacedintheL-position,thefirstandreverse brake(B3)isappliedthroughthepositionofthemanualvalve.The firstandreversebrakedoesthesamethingastheone-wayclutchNo.2 (F2)intheforwarddirection,asseenintheillustration.Whenthefirst andreversebrake(B3)isapplieditholdstherearplanetarygear carrierfromturningineitherdirection.Whereastheone-wayclutch No.2onlyholdsthecarrierinthecounterclockwisedirection.The advantagethatthefirstandreversebrakehasisthatenginebraking canbeachievedtoslowthevehicleondeceleration.In“D1“only,the one-wayclutchNo.2holdsthecarrier,sowhiledecelerating,the one-wayclutchwouldreleaseandnoenginebrakingwouldoccur. First Gear First and Reverse Brake (B3) holds the rear carrier. The No. 2 On-Way Clutch holds the rear carrier Differences Between D1- and L- Range First GearPOWER FLOW Automatic Transmissions - Course 262 59 First Gear The rear planetary carrier cannot rotate in either direction. The rear planetary carrier is held counter-clockwise only and freewheels in the clockwise direction. Threediagnosticscenarios: 1. Iftherewasslippageinreversegearbutnonein“L“position,and noenginebrakingwhendeceleratingin“L,“thefirstandreverse (B3)wouldbeatfault.Slippageinfirstgeardidnotoccurbecause theone-wayclutchNo.2(F2)wouldhaveheldtherearcarrierfrom turningcounterclockwise. 2. Iffirstgearslipsin“D1l“andthereisnoslippagein“L,“the one-wayclutchNo.1(Fl)isatfault. 3. Thereisslippageinfirstgearwiththeselectorin“D“and“L.“The holdingdevicecommontobothgearpositionswouldbetheforward clutch(C1).Section 5 60 TOYOTA Technical Training Whenthegearselectorisplacedinthe2-position,thesecondcoast brake(Bl)isappliedbywayofthemanualvalve.Whenthesecond coastbrakeisapplied,itholdsthesungearfromrotatingineither direction.Powerflowisthesameaswhenthetransmissionisdriving thewheelswiththeselectorin2,aswhentheselectorisinD. However,whenthetransmissionisbeingdrivenbythewheelson deceleration,theforcefromtheoutputshaftistransmittedtothefront carrier,causingthefrontplanetarypiniongearstorevolveclockwise aroundthesungear.Sincethesungearisheldbythesecondcoast brake,theplanetarygearswalkaroundthesunclockwiseanddrive thefrontplanetaryringgearclockwisethroughtheinputshaftand torqueconvertertothecrankshaftforenginebraking.Incontrast, whileinsecondgearwiththeselectorinD-position,thesungearis heldinthecounterclockwisedirectiononlyandthesungearrotatesin aclockwisedirectionandthereisnoenginebraking. Theadvantagethat“2“rangehasover“D2“isthattheenginecanbe usedtoslowthevehicleondeceleration,andthisfeaturecanbeusedto aidindiagnosis.Forexample,atransmissionwhichdoesnothave secondgearinD-positionbutdoeshavesecondgearwhilemanually shiftingcanbenarrowedtothesecondbrake(B2)orone-wayclutch#1 (Fl).Thesecomponentsandrelatedhydrauliccircuitsbecomethe primaryfocusinourdiagnosis. Second Gear The second coast brake (B1) holds the sun gear. The second brake (B2) and No. 1 One-Way Clutch (F1) hold the sun gear. Differences Between D2- and 2-Range Second GearPOWER FLOW Automatic Transmissions - Course 262 61 Second Gear The sun gear cannot rotate in either direction. The sun gear is held in the counter-clockwise direction only and freewheels in clockwise direction.Section 5 62 TOYOTA Technical Training Onesimpleplanetarygearsetisaddedtothe3-speedautomatic transmissiontomakeita4-speedautomatictransmission(three speedsforwardandoneoverdrive).Thisadditionalgearsetcanbe addedinfrontoforbehindtheSimpsonPlanetaryGearSetto acc
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