附錄1組合式機(jī)械變速器的現(xiàn)狀和發(fā)展重型汽車裝載質(zhì)量大，使用條件復(fù)雜，欲保證其具有良好的動(dòng)力性、經(jīng)濟(jì)型和加速性，則必須擴(kuò)大傳動(dòng)比范圍并增加擋數(shù)。傳統(tǒng)結(jié)構(gòu)三軸式變速器檔位數(shù)一般最多為5個(gè)前進(jìn)擋和1個(gè)倒檔，最大輸出轉(zhuǎn)矩為8400Nm。近幾年重型汽車發(fā)動(dòng)機(jī)功率200350kw，輸出轉(zhuǎn)矩9002200Nm，需要爬行檔速比1017，要求檔位間隔小，速比階小于30%，這就需要更多檔位（816個(gè)前進(jìn)擋）。先讓傳統(tǒng)結(jié)構(gòu)的三軸式變速器遠(yuǎn)不能滿足上述要求，分段式配檔（倍檔）和插入式配檔（半檔）的組合式變速器應(yīng)運(yùn)而生。倍檔組合式變速器是在主變速器后部串聯(lián)安裝一個(gè)2檔（高檔和低檔）副變速器，是主變速器的檔位數(shù)增加1倍，所增加的檔位傳動(dòng)比數(shù)值等于主變速器傳動(dòng)比和副變速器傳動(dòng)比的乘積，而且齒輪對(duì)數(shù)少于檔位數(shù)，因此箱體尺寸縮短，軸的長(zhǎng)度減短，剛度增大，所以增大了變速器的容量。例如在一個(gè)5檔組變速器后端，串聯(lián)安裝一個(gè)具有高、低2檔的副吧變速器，即可組成10檔（或9檔）倍檔組合式機(jī)械變速器。增加倍檔組合式變速器最大輸入扭矩和最低檔傳動(dòng)比的技術(shù)難點(diǎn)是副變速器齒輪強(qiáng)度容量不足，超出齒輪輪齒的承載能力。解決的辦法將有一個(gè)齒輪承受的載荷分流給幾個(gè)齒輪來(lái)承受。這樣，輸入齒輪扭矩不變，每個(gè)齒輪的負(fù)荷將等于同時(shí)接觸齒輪的平均數(shù)值。倍檔組合式變速器的副變速器功率分流方法有兩種：一種是采用形象齒輪系的傳動(dòng)方法。這種結(jié)構(gòu)非常緊湊，體積小而扭矩容量大，直到現(xiàn)在仍廣泛應(yīng)用；另一種方法是采用雙中間軸傳動(dòng)結(jié)構(gòu)。雙中間軸傳動(dòng)最大工藝難點(diǎn)是保證主傳動(dòng)齒輪能和所嚙合的雙中間軸齒輪的輪齒同時(shí)接觸問(wèn)題，解決的辦法是用浮動(dòng)主傳動(dòng)齒輪的方法來(lái)消除齒軸對(duì)位的制造誤差，確保齒輪同時(shí)接觸，達(dá)到功率分流的目的。與此相適應(yīng)的換擋同步器也要有一定的浮動(dòng)量。半檔組合式變速器是將副變速器傳動(dòng)比均勻的插入傳動(dòng)比間隔大的主變速器各檔傳動(dòng)比之間，式變速器的檔位數(shù)增加1倍。半檔副變速器串聯(lián)在主變速器前部，它只有一對(duì)齒輪副和同步器。早起的半檔副變速器由單獨(dú)的一個(gè)箱子組成，近年來(lái)發(fā)展成將半檔齒輪副直接放到變速器之內(nèi)，既縮短變速器長(zhǎng)度由簡(jiǎn)化半檔結(jié)構(gòu)。半檔副變速器由一對(duì)類似一軸常嚙合齒輪副組成，齒圈套在動(dòng)力輸入軸上自由轉(zhuǎn)動(dòng)，當(dāng)動(dòng)力輸入軸上的齒圈與住變速器一軸結(jié)合時(shí)，各檔傳動(dòng)比均由主變速器一軸齒輪副組成。當(dāng)齒圈與動(dòng)力輸入軸上的結(jié)合齒輪的齒圈連接時(shí)，常嚙合齒輪與主變速器上的中間軸連接，因此主變速器中間軸也旋轉(zhuǎn)，由此組成的各檔傳動(dòng)比均勻地插入主變速器各檔位傳動(dòng)比之間。因?yàn)榘霗n組合式變速器的長(zhǎng)度小于倍檔組合式變速器，而且他的結(jié)構(gòu)簡(jiǎn)單、成本低、維修保養(yǎng)容易深受用戶青睞。國(guó)外貨車采用組合式變速器的情況是：發(fā)動(dòng)機(jī)的功率在200kw以下的汽車基本上采用半檔組合式變速器；發(fā)動(dòng)機(jī)功率在200kw以上的多采用倍檔（或倍檔加半檔）組合式變速器。附錄2CombinedmechanicaltransmissionofthepresentandthefutureHeavydutytruckmountqualityconditionsfortheuseoflarge,complex,andtoensureitsexcellentdynamicperformance,economicalandAcceleration,youmustexpandthescopeofthetransmissionratioandincreasethenumberofguards.Traditionalstructureofthree-shaftgearboxstallnumberusuallyuptofiveforwardvisorand1reversegear,maximumoutputtorquefor8400Nm.Inrecentyears,heavydutytruckenginepower200350kw,outputtorque9002200Nm,crawlingstallsratio1017,stalls,speedratio-orderintervalislessthan30%,andthisrequiresmorestalls(816forwardgear).Letthetraditionalstructureofthree-shaftgearboxisfarfromabletosatisfytheaboverequirements,thesegmentaldistributionoutlets(doublestalls)andinsert-withfile(file)ofacombinedtransmissioncameintobeing.Timesthestalliscombinedinthemaintransmissiongearboxback-lineinstalleda2stalls(high-gradeandlow-grade)Deputytransmission,istheprimarytransmissiongearnumberdoubled,theincreaseinstallspeedratiovalueequaltothemaintransmissiongearratioandtheproductofDeputytransmissiongearratioandthenumberofgear,thelogarithmislessthanthestallsoboxsizereducedthelengthoftheshaft,stiffnessincreasereduced,increasingthetransmissioncapacity.Forexample,ina5stallsgrouptransmissionbackend,in-lineinstallationofahighandlowsidebar2stalls,composedof10transmissionstostall(or9stalls)timesthestallcombinedmechanicaltransmission.IncreasetimesstalltranmisssionmaxinputtorqueandlowtransmissionratiooftechnicaldifficultyisDeputytransmissiongearstrengthcapacityisinsufficient,excessgearcarryingcapacity.Thesolutionwillhaveagearbearloadshunttoseveralgeartobear.Inthisway,theinputgeartorqueconstant,eachgearloadwillbeequaltotheaveragecontactgearatthesametime.Timesthestallsofthecombinedtransmissiontransmissionpowersplittwoways:oneistheimageofthedrivegeartrains.Thisstructureisverycompact,smallandbigtorquecapacityuntilnowisstillwidelyused；thealternativeistousetwointermediateshafttransmissionstructure.DoubleMiddleshaftdrivemaximumprocessdifficultiesisthatmaindrivegearandthemeshofthetwin-shaftgearteethatthesametime,contacts,thesolutionistousefloatingmethodmaindrivegeartoeliminatetoothshaftalignmentofmanufacturingerrors,ensurethatthegearatthesametime,meetthepowersplitends.AdapttoshiftingtheSynchronizershouldalsohaveacertainamountoffloating.HalfstallsiscombinedtransmissiontransmissiongearratioevenViceinsertratiospacingoftheprimarytransmissionbetweenvariousstallstransmissionratio,thenumberoftransmissionsofstallsdoubled.Half-stallsontheprimaryDeputytransmission-linetransmissionfront,itisonlyapairofgearsandSynchronizer.Earlyhalfgearpairtransmissionfromasinglebox,inrecentyearsdevelopedintohalf-gearpairdirectlyonthetransmission,whichshortenthetransmissionlengthfromahalfstallsstructure.simplificationHalfstallsVicetransmissiongearboxbyasimilaroneaxisconstantgearpair,toothsnaresindynamicinputshaftrotatefreely,whenpowerinputshaftgearandlivetransmissionwithanaxis,thestallspeedratioofthemaintransmissionashaftgears.Whentheringgearandpowerinputshaftonthecombinationofgeartoothringconnection,gearandmaintransmissiononintermediateshaftconnection,thereforethemaintransmissiongearboxshaftisrotated,constitutingthestallspeedratioevenlyintothemaintransmissionbetweenthestallspeedratio.Becausehalfthelengthofacombinedtransmissionspeedislessthandoublestallscombinedgearbox,andhissimp