道岔結構及作用StructureandFunctionof

RailwaySwitch天津鐵道職業技術學院鐵路信號基礎設備維護把兩條或兩條以上的軌道，在平面上進行相互連接或交叉的設備稱為道岔。其作用是使機車車輛由一條軌道轉入或越過另一條軌道，以滿足鐵路運輸中的各種作業需要，也是鐵路信號的主要控制對象之一。道岔因其構造不同而形式多樣，最常見的是普通單開道岔。高速鐵路道岔轉轍設備結構組成及作用StructureandFunctionofHigh-SpeedRailwaySwitchTheequipmentthatconnectsorcrossestwoormoretracksontheplaneiscalledturnout.Itsfunctionistomaketherollingstockturnintoorcrossoveranothertrackfromonetrackforvariousoperationneedsinrailroadtransportation,andisalsooneofthemaincontrolobjectsofrailroadsignal.Theturnoutisindifferentformsduetoitsstructure,andthemostcommononeisthecommonsingleopenturnout.高速鐵路道岔轉轍設備結構組成及作用（一）單開道岔的組成普通單開道岔有左開和右開之分，是最常見、最簡單的線路連接設備。普通單開道岔的組成包括轉轍器、轍叉及護軌、連接部分，如圖所示。StructureandFunctionofHigh-SpeedRailwaySwitch1.CompositionofsingleturnoutThecommonsingle-openingturnoutisthemostcommonandsimplestlineconnectionequipment,withtypesofleft-openingandright-openingturnouts.Thecompositionofcommonsingle-openingturnoutincludesswitchmachine,frogandguardrail,andconnectingpart,asshowninFigure.高速鐵路道岔轉轍設備結構組成及作用1.轉轍器由兩根尖軌、兩根基本軌及轉轍機械組成，如圖所示。尖軌是轉轍器的主要部件，通過連接桿與轉轍機械相連，操縱轉轍機械就可變換尖軌的位置，以確定道岔的開通方向。2.轍叉及護軌包括可動心軌、翼軌及護軌。其作用是保證車輪安全通過兩條鋼軌的相互交叉處。可動心軌是為了防止列車經過兩翼軌最窄處到轍叉心時，車輪輪緣走錯轍叉輪緣槽而導致脫軌設計的，可以減輕車輪對翼軌和心軌的沖擊，適應列車高速運行。如圖，當尖軌開通某一方向時，活動心軌的轍叉心就與開通方向一致的翼軌密貼，與另一翼軌分開。3.連接部分包括連接轉轍器和轍叉及護軌的部分。它包括直線軌和導曲線軌。由于導曲線的半徑較小，又不能在導曲線上設置緩和曲線和超高，所以列車在側向過岔時，速度要受到嚴格的限制。1.SwitchmachineItiscomposedoftwotonguerails,twostockrailsandswitchmechanism,asshowninFigure.Thepointedrailisthemainpartoftheswitchmachine,whichisconnectedtotheswitchmachinethroughtheconnectingrod,andthepositionofthepointedrailcanbechangedbymanipulatingtheswitchmachinetodeterminetheopeningdirectionoftheturnout.2.FrogandguardrailFrogandguardrailincludesmovablefrograil,wingrailandguardrail.Itensuresthesafetyofthewheelsthroughtheintersectionoftworails.Themovablecenterrailisdesignedtopreventderailmentcausedbythewheelflangegoingtothewrongfrogflangegroovewhenthetrainpassesthroughthenarrowestpartofthetwowingrailstothefrogcenter.Itcanreducetheimpactfromthewheeltothewingrailsandfrograil,andadapttohigh-speedtrainoperation.AsshowninFigure,whenthetonguerailisopenedtoacertaindirection,theswitchforkheartofthemovablefrograilisclosetothewingrailthatisopenedinthesamedirectionandseparatedfromtheotherwingrails.3.ConnectingpartsConnectingpartsincludepartsconnectingswitchandfrogandrailguard.Itincludesstraightrailandguidecurverail.Becausetheradiusoftheguidecurveissmall,andthetransitioncurveandultrahighcannotbesetontheguidecurve,thespeedofthetrainisstrictlylimitedwhenpassingtheturnoutlaterally.StructureandFunctionofHigh-SpeedRailwaySwitch高速鐵路道岔轉轍設備結構組成及作用（二）道岔號由岔心所形成的角，叫轍叉角，它有大有小。道岔號碼（N）是代表道岔各部主要尺寸的。通常用轍叉角α的余切來表示。如圖所示，即：N=cotα。道岔號與轍叉角α成反比關系，α角越小，N越大，導曲線半徑也越大，機車車輛通過該道岔時就越平穩，允許過岔速度也就越高。所以采用大號碼道岔對于列車運行是有利的。隨著列車重量和速度的不斷提高，應逐步采用強度更高，號碼更大的道岔。鐵路的主要線路上大多采用9、12、18號三個型號的道岔，其通過速度如表2.TurnoutnumberTheangleformedbytheforkiscalledfrogangle,whichcanbelargeorsmall.Theturnoutnumber(N)representsthemainsizeofeachpartoftheturnout.ItisusuallyexpressedasthecotangentofthefrogAngleα.

N=cotαStructureandFunctionofHigh-SpeedRailwaySwitch

ItcanbeseenfromtheformulathattheturnoutnumberisinverselyproportionaltothefrogAngleα.ThesmallertheαAngleis,thelargertheNis,thelargertheradiusoftheguidecurveis,themorestablethelocomotiveandvehiclewillbewhencrossingtheswitch,andthehighertheallowablecrossingspeedis.Sotheuseoflargeturnoutfortrainoperationisadvantageous.Withtheincreasingweightandspeedoftrains,higherstrengthandlargernumbersofswitchesshouldbegraduallyadopted.

MostofthemainrailwaylinesadoptthreetypesofturnoutNo.9,12and18,andtheirpassingspeedsareshowninTable高速鐵路道岔轉轍設備結構組成及作用（三）道岔的位置和狀態由圖所示，道岔有兩根可以移動的尖軌，一根密貼于基本軌，另一根尖軌離開基本軌，可以同時改變兩根尖軌的位置，使原來密貼的分離，而原來分離的密貼，可見道岔有兩個可以改變的位置。我們通常把道岔經常所處位置叫做定位，臨時根據需要改變的另一位置叫做反位。為改變道岔的兩個位置，在道岔尖軌處需要安裝道岔轉轍設備。3.Locationandstatusofturnout

AsshowninFigure,theturnouthastwomovabletonguerails,oneiscloselyattachedtothestockrail,andtheotherisawayfromthestockrail.Thepositionofthetwotonguerailscanbechangedatthesametime,sothattheoriginaltightpasteisseparated,andtheoriginalseparatedtightpasteshowsthattheturnouthastwopositionsthatcanbechanged.Weusuallyrefertotheregularpositionoftheturnoutaspositioning,temporarychangeaccordingtotheneedofanotherpositioniscalledreverse.Tochangethetwopositionsoftheswitch,installaswitchingdeviceattheswitchrail.StructureandFunctionofHigh-SpeedRailwaySwitch高速鐵路道岔轉轍設備結構組成及作用（四）對向道岔和順向道岔道岔本身并無順向和對向之分。這只是根據列車運行方向而言的。列車迎著道岔尖軌運行時，該道岔就叫對向道岔。反之，列車順著道岔尖軌運行時叫順向道岔。如圖所示。4.OppositeturnoutandforwardturnoutTheturnoutitselfhasnodifferencebetweenforwarddirectionandoppositedirection.Thisisonlybasedonthetrainrunningdirection.Whenthetrainrunsagainsttheswitchrail,theswitchiscalledtheoppositeswitch.Onthecontrary,whenthetrainrunsalongtheturnoutswitchrail,itiscalledaforwardturnout,asshowninFigureStructureandFunctionofHigh-SpeedRailwaySwitch高速鐵路道岔轉轍設備結構組成及作用（五）單動道岔和雙動道岔按壓一個道岔按鈕（電動道岔的操縱元件），如僅能使一組道岔轉換，則稱該道岔為單動道岔；如果能使兩組道岔同時或順序轉換，則稱為雙動道岔，有時也稱為聯動道岔，故它有三動和四動的情況。為了簡化操作手續，簡化聯鎖關系，凡是能雙動的道岔必須使之雙動。“雙動”即意味著兩組道岔可作為一個控制對象來處理。如圖所示。很明顯，使用雙動不但手續簡化，而且設備也簡單了。確定為雙動道岔必須符合下列條件：1.開通一條進路，要求兩組道岔都必須在反位。即列車要經過這兩組道岔的反位位置2.開通一條進路，要求兩組道岔中的任何一組在定位，而另一組也在定位時，并且不影響平行進路。3.1/3為雙動道岔，對雙動道岔的基本要求是：定位時都必須轉換到定位，反位時又都必須轉換到反位。5Single-actingturnoutanddouble-actingturnoutPressaswitchbutton(thecontrolelementoftheelectricswitch),ifonlyagroupofswitchescanbeconverted,theswitchiscalledasingleswitch;Iftwogroupsofswitchescanbeconvertedsimultaneouslyorsequentially,itiscalledadouble-actingswitch.Double-actingturnoutisalsosometimescalledlinkageturnout,soithasthree-andfour-actingsituation.Inordertosimplifytheoperationproceduresandtheinterlockingrelationship,allturnoutsthatcanbedoubleoperatedmustbedoubleoperated"Doubleacting"meansthattwosetsofswitchescanbetreatedasonecontrolobject,asshowninFigure.Obviously,usingd