英文原文版出處歐洲專(zhuān)利數(shù)據(jù)庫(kù).專(zhuān)利-EP19820102738譯文成績(jī)：指導(dǎo)教師（導(dǎo)師組長(zhǎng)）簽名：譯文：串聯(lián)驅(qū)動(dòng)橋系統(tǒng)摘要：串聯(lián)驅(qū)動(dòng)橋系統(tǒng)是不同的，其能夠從車(chē)輛處將電源供給輸入扭矩，既第一、第二后驅(qū)動(dòng)橋以及前驅(qū)動(dòng)橋。設(shè)置為允許電源從它們的側(cè)齒輪一端被發(fā)送到第二后驅(qū)動(dòng)橋，然后通過(guò)差速齒輪的輸入轉(zhuǎn)矩劃分。另一側(cè)齒輪的輸出齒輪能夠發(fā)送至少一部分的輸出轉(zhuǎn)矩，從而可操作性的耦合至第一后驅(qū)動(dòng)橋的第一齒輪。一個(gè)惰輪與輸出齒輪驅(qū)動(dòng)嚙合，并且反過(guò)來(lái)，驅(qū)動(dòng)第二齒輪選擇性地耦合到傳輸?shù)钠溆嗖糠?，即從輸出齒輪輸出轉(zhuǎn)矩到前驅(qū)動(dòng)橋。如果選擇性地脫開(kāi)正向驅(qū)動(dòng)橋，惰齒輪和第二齒輪，第二齒輪將被允許自由運(yùn)行。本專(zhuān)利是在技術(shù)領(lǐng)域的發(fā)明。本發(fā)明涉及到串聯(lián)驅(qū)動(dòng)橋系統(tǒng)，更具體地來(lái)說(shuō)，其中的有關(guān)改進(jìn)裝置是用于有選擇地將動(dòng)力傳遞到具有前驅(qū)動(dòng)橋以及第一和第二后驅(qū)動(dòng)橋的車(chē)輛的前驅(qū)動(dòng)橋。在現(xiàn)有技術(shù)的說(shuō)明下，此串聯(lián)6×6的車(chē)輛也就是俗稱(chēng)的車(chē)輛驅(qū)動(dòng)橋系統(tǒng)，具體而言，6×6的車(chē)輛，其中包括六個(gè)輪子在地面上都被驅(qū)動(dòng)車(chē)輛用作電源。通常情況下，一個(gè)6×6的車(chē)輛在正常行駛條件下，驅(qū)動(dòng)系統(tǒng)能夠被選擇性地改變，以消除權(quán)力的應(yīng)用，這樣的前驅(qū)動(dòng)橋其實(shí)只有用在正在供電電源兩個(gè)后軸上。在這種情況下，車(chē)輛將被適當(dāng)?shù)孛枋鰹橐粋€(gè)6×4輛可以在一個(gè)6×4模式操作。

在圖2和圖3中可以看出，差速器殼體18包括本發(fā)明的分裂和發(fā)送功率是各車(chē)軸的主要元素。具體而言，輸入軸34可轉(zhuǎn)動(dòng)地安裝在軸承36與差速器殼體18之內(nèi)，包括一個(gè)連接件38的驅(qū)動(dòng)軸16（圖中未示出）接合。一個(gè)差速器齒輪組40被安裝在輸入軸34的后端，并包括一個(gè)差分籠和蜘蛛42剛性地聯(lián)接到軸34。差保持架和蜘蛛42包括小齒輪44，它能夠?qū)?dòng)力傳遞到第一差動(dòng)側(cè)齒輪46和第二差動(dòng)側(cè)齒輪48。

差動(dòng)側(cè)齒輪46安裝在輸入軸34上，并能夠獨(dú)立的相對(duì)轉(zhuǎn)動(dòng)。同樣，第二個(gè)差動(dòng)側(cè)齒輪48安裝在輸入軸34上能夠獨(dú)立的相對(duì)轉(zhuǎn)動(dòng)，基本上是由軸承50用于支撐所述輸入軸32的后端部的方式支持，其中側(cè)齒輪48的輸入軸34在其中接收的后端。第二差動(dòng)側(cè)齒輪48是剛性地連接到向后延伸的軸裝置48，從差速器殼體18的后部延伸，有與第二向后延伸的驅(qū)動(dòng)軸24（圖中未示出）耦合。因此，接收功率在第二個(gè)差動(dòng)側(cè)齒輪48上，能夠提供電源的方式是在向后定位的后軸22上的。

第一差動(dòng)側(cè)齒輪46包括在其前端的輸出齒輪54，它能夠發(fā)送接收由所述第一差動(dòng)側(cè)齒輪46的輸出功率。要傳輸?shù)妮敵龉β实囊徊糠謴乃龅谝徊罘謧?cè)齒輪46的向前定位的后軸20出與第一齒輪56對(duì)準(zhǔn)并與輸出齒輪54嚙合接觸。第一齒輪56剛性地安裝在一個(gè)軸58上，反過(guò)來(lái)，可轉(zhuǎn)動(dòng)地安裝在軸承60內(nèi)的差速器殼體18的內(nèi)部。輸入小齒輪62安裝在軸58的后端，并在一個(gè)差分驅(qū)動(dòng)橋差速器上提供向前定位的后驅(qū)動(dòng)橋20的輸出轉(zhuǎn)矩的機(jī)構(gòu)（圖中未示出）的環(huán)形齒輪64嚙合接觸。如這樣描述，從電源12的輸入轉(zhuǎn)矩能夠提供給后軸20和22，因?yàn)樗潜怀圆钏倨鼾X輪組40。具體而言，根據(jù)在一個(gè)理想的操作條件下，其中在車(chē)輛運(yùn)行大致均勻分布的各車(chē)軸上的負(fù)荷與相對(duì)水平的表面上，在每個(gè)差側(cè)齒輪46，48的輸出轉(zhuǎn)矩上將大約一半的從電源12接收輸入扭矩。如果車(chē)輛是在一個(gè)6×4模式操作，從而所述驅(qū)動(dòng)橋系統(tǒng)將工作在本領(lǐng)域中公知的方式與基本除以兩個(gè)后置串聯(lián)軸20和22之間的所有的負(fù)載間差速器40被認(rèn)為是必要的，因?yàn)?，在?shí)際操作中的負(fù)載不會(huì)被均勻地分布在兩軸差速器之間仍然可以進(jìn)行車(chē)輛操作，同時(shí)允許一些偏差，或者在兩軸之間的不同taction條件現(xiàn)實(shí)可能性。

然而，由于是驅(qū)動(dòng)橋在藝術(shù)上也是眾所周知的，差速器40提供的分化有的是在不希望的場(chǎng)合。因?yàn)樗赡苁擒?chē)輪與車(chē)軸20，22相關(guān)的，在這樣非牽引沒(méi)有電源的情況下，可以適用于驅(qū)動(dòng)車(chē)輛的運(yùn)動(dòng)表面，經(jīng)常包括裝置，用于“鎖定“的差，以確保兩個(gè)軸同時(shí)移動(dòng)，其中軸與驅(qū)動(dòng)表面的足夠接觸。將能夠推進(jìn)車(chē)輛。要做到這一點(diǎn)，離合器裝置66將要被安裝在輸入軸34上的一組向外延伸的齒67上。如圖3所示，離合器裝置66的向前位置，不影響分化差速器40提供的運(yùn)動(dòng)。然而，為了實(shí)現(xiàn)“鎖定”狀態(tài)，以防止分化，有些裝置的換檔桿和叉的形式（未示出），它可以作用于周向槽68的離合器裝置66，導(dǎo)致在輸入軸34上的齒67沿軸向向后移動(dòng)。當(dāng)離合器裝置66被充分地向后移動(dòng)時(shí)，它將被帶進(jìn)對(duì)應(yīng)與第一差動(dòng)側(cè)齒輪46連接的第一差動(dòng)側(cè)齒輪46，同時(shí)直接連接到輸入軸34的前端上的一組齒輪齒70進(jìn)行嚙合。當(dāng)?shù)谝徊顒?dòng)側(cè)齒輪46聯(lián)接到輸入軸34上，就沒(méi)有進(jìn)一步的分化，然后將要發(fā)送的輸入轉(zhuǎn)矩，輸出齒輪54或向后延伸的軸52通過(guò)根據(jù)創(chuàng)建的每個(gè)后部的電阻軸20，22進(jìn)行與驅(qū)動(dòng)面接觸。如上所述，本發(fā)明和美國(guó)專(zhuān)利號(hào)4050534中公開(kāi)的驅(qū)動(dòng)橋系統(tǒng)都是包含在差速器殼體18內(nèi)的裝置，用于提供輸出的前驅(qū)動(dòng)橋28。在美國(guó)專(zhuān)利號(hào)4050534中，這是通過(guò)有一個(gè)額外的驅(qū)動(dòng)嚙合齒輪與第一齒輪56中進(jìn)行的，當(dāng)輸出齒輪54接收到輸出轉(zhuǎn)矩時(shí)，將能夠提供電源給前部驅(qū)動(dòng)器軸28和向前定位后驅(qū)動(dòng)橋20。其結(jié)果是，所有的功率將被發(fā)送到這兩個(gè)車(chē)軸具體在一個(gè)單一的輸出齒輪54與第一齒輪58之間的嚙合接觸點(diǎn)來(lái)進(jìn)行發(fā)送。然而，在最壞的情況下，也有可能是足夠的滑動(dòng)，以使離合器裝置66被用來(lái)防止分化差速器40在向后定位中車(chē)輛操作的后軸22。如果車(chē)輛負(fù)載較大，并且有優(yōu)良的道路牽引前驅(qū)動(dòng)橋28和向前定位的后軸20，所有的輸入功率將與電源連接發(fā)送到這兩個(gè)軸通過(guò)單一的輸出齒輪54。雖然這不會(huì)是一個(gè)正常的運(yùn)行狀態(tài)，它不會(huì)是不尋常的，在這種高負(fù)荷的情況下也會(huì)定期發(fā)生。由此產(chǎn)生的應(yīng)力在單個(gè)嚙合接觸點(diǎn)的輸出齒輪54與第一齒輪56的齒磨損可能是顯然不利影響整體驅(qū)動(dòng)橋系統(tǒng)的可靠性和壽命。

因此，在優(yōu)選實(shí)施例中，提供電源到前驅(qū)動(dòng)橋28包括一個(gè)惰輪72，它是與輸出齒輪54嚙合接觸，但其上的位置處的周向間隔開(kāi)的接合點(diǎn)與所述第一齒輪56是斷開(kāi)的。惰齒輪72剛性地安裝在惰軸74上，其可轉(zhuǎn)動(dòng)地安裝在軸承76內(nèi)的差速器殼體18之間。提供動(dòng)力的前驅(qū)動(dòng)橋28，包括第二齒輪78相嚙合的從動(dòng)齒輪72，使兩個(gè)齒輪72，78進(jìn)行響應(yīng)的輸出齒輪54旋轉(zhuǎn)轉(zhuǎn)動(dòng)。

第二齒輪78安裝在軸80上，并能夠獨(dú)立的相對(duì)轉(zhuǎn)動(dòng)，其上的軸80被安裝在軸承82與差速器殼體18之內(nèi)，并包括一個(gè)前端，其向前延伸的驅(qū)動(dòng)軸30被連接到用于提供電源的前驅(qū)動(dòng)橋28之上。第二齒輪78剛性地安裝在軸80上的，在本發(fā)明的優(yōu)選實(shí)施例中，包括一個(gè)裝置，用于有選擇地將動(dòng)力傳遞到前驅(qū)動(dòng)橋28。這是通過(guò)以知的方式進(jìn)行的動(dòng)力傳遞。如上所述，離合器84安裝在向外延伸的齒85的軸80，可以有選擇地，向后定位成接合向外延伸的齒86剛性連接第二齒輪78的軸80的動(dòng)力傳遞到第二齒輪78上，當(dāng)前驅(qū)動(dòng)橋28，6×6的運(yùn)作模式是隨意的。前列位置將重新定位離合器84脫開(kāi)第二齒輪78到軸80上，并允許自由運(yùn)行的惰齒輪72和第二齒輪78，在沒(méi)有任何的動(dòng)力傳遞到前驅(qū)動(dòng)橋28之上，從而返回車(chē)輛到6×4的操作模式。

然而，在本發(fā)明中使用的配置，如果車(chē)輛再次與差速器“鎖定”，在最壞的情況下操作，功率將被傳輸?shù)捷S28和20之間，將不再被集中在一個(gè)在輸出齒輪54上。基本上，在嚙合的輸出齒輪54與惰齒輪72中，剩下的一半的輸出轉(zhuǎn)矩的驅(qū)動(dòng)向前定位后軸20被提供給的一半將被傳送發(fā)送到正向驅(qū)動(dòng)橋28的負(fù)載上，因?yàn)樗佑|在不同的周向位置與輸出齒輪54的第一齒輪56上。輸出齒輪54的齒的磨損和應(yīng)力顯著降低，以改善整體可靠性。如這樣描述的，本發(fā)明以公開(kāi)在美國(guó)專(zhuān)利號(hào)為405053相同的方式提供電源，一般地但包括裝置，用于保證在最壞的情況中驅(qū)動(dòng)橋系統(tǒng)的可靠性。此外，還有一些設(shè)計(jì)上的限制，在美國(guó)專(zhuān)利號(hào)4050534中公開(kāi)的驅(qū)動(dòng)橋系統(tǒng)預(yù)先確定的軸的相對(duì)位置是從差速器殼體提供電力以使各車(chē)軸延伸。由于提供電力，在該現(xiàn)有技術(shù)的驅(qū)動(dòng)輪軸系統(tǒng)上前驅(qū)動(dòng)橋齒輪嚙合的齒輪，其提供電源的向前定位的后軸向前延伸的輸出軸相對(duì)的位置，在一個(gè)有限的范圍內(nèi)接收到輸入軸電源的功率。然而，一個(gè)惰輪的使用中，所提供的前驅(qū)動(dòng)橋提供動(dòng)力的軸，該軸可以被重新定位，而不必是一個(gè)預(yù)定的距離，在垂直或水平方向相對(duì)于所述軸驅(qū)動(dòng)的向前定位的后軸相比。它甚至是可能的，如果要重定位不同分離的第一齒輪的橫向平面的軸向向前將會(huì)比第二齒輪惰齒輪的橫向平面長(zhǎng)。在這個(gè)位置上，第二齒輪可以調(diào)整的部分“疊置”從正面觀察時(shí)，各自的軸向前和向后到可以延伸的第一齒輪上。因此，通過(guò)包括在空轉(zhuǎn)齒輪72，本發(fā)明的驅(qū)動(dòng)橋系統(tǒng)能提供一個(gè)更好的從輸出齒輪54的功率分布，并允許更大的靈活性，從差速器殼體18的軸延伸的設(shè)計(jì)位置的正向驅(qū)動(dòng)橋28和向前定位的后軸20的操作。

英文原文：Tandemdriveaxlesystem摘要Animprovedtandemdriveaxlesystemisofthetypewhichiscapableofsupplyinginputtorquefromavehiclepowersourcetofirstandsecondreardriveaxlesandafrontdriveaxle.Theinputtorqueisdividedthroughadifferentialgearsettoallowpowertobetransmittedfromoneofthesidegearsthereoftothesecondreardriveaxle.Anoutputgearassociatedwiththeothersidegeariscapableoftransmittingatleastaportionoftheoutputtorquetherefromtoafirstgearwhichisoperablycoupledtothefirstreardriveaxle.Anidlergearisalsoindrivingengagementwiththeoutputgearand,inturn,drivesasecondgearwhichisselectivelycoupledtothefrontdriveaxletotransmittheremainderoftheoutputtorquefromtheoutputgear.Ifthesecondgearisselectivelyuncoupledfromtheforwarddriveaxle.FieldoftheInvention.Thisinventionrelatestoatandemdriveaxlesystemand,morespecifically,toanimprovementthereinrelatingtothemeansforselectivelytransmittingpowertothefrontdriveaxleofavehiclehavingafrontdriveaxleandfirstandsecondreardriveaxles.DescriptionofthePriorArt.Thisinventionrelatestoatandemdriveaxlesystemforavehiclewhichiscommonlyknownasa6x6vehicle.Specifically,a6x6vehicleisonewhichincludessixwheelsonthegroundwhichareallbeingdrivenbythevehiclepowersource.Typically,undernormaldrivingconditions,thedrivesystemofa6x6vehicleiscapableofbeingselectivelyalteredtoeliminatetheapplicationofpowertothefrontdriveaxlesothatinfactonlypowerisbeingsuppliedtothetworearaxles.Inthissituation,thevehiclewouldbeappropriatelydescribedasa6x4vehicle.Atonetime,itwascommonpracticetodividepowerbetweenthefrontdriveaxleandthepairofreardriveaxlesthroughatransfercase.AsshowninU.S.PatentNumbers2,770,150;3,095,758;3,191,708and3,495,477,suchtransfercasescanbeutilizedtoreceiveaninputtorquefromthevehiclepowersourceortransmissionandtosupplyoutputtorquetoaforwardlyextendingshaftfordrivingthefrontdriveaxleandarearwardextendingshaftwhichiscapableofdrivingoneortworeardriveaxles.Whilesuchconfigurationshavebeensatisfactorilyemployedinthepast,theuseofatransfercaseinvolvesadditionalgearingandsubstantiallyincreasestheweightandcostofsuchadrivesystem.Accordingly,inordertoeliminatesomeoftheobjectionsofthistypeofdrivesysteminwhichatransfercaseisrequired,U.S.PatentNumber4,050,434disclosesavehicledriveaxlesystemwhichiscapableofbeingutilizedon6x6vehicleswhichcanbeselectivelyoperatedinthe6x4modeasmentionedhereinabove.Specifically,thevehicledrivesystemdisclosedthereinutilizesaninputshaftfromthevehiclepowerortransmissionsystemtoainteraxledifferentialconfigurationtodriveadifferentialgearsethavingfirstandsecondsidegearmeans.Thefirstsidegearmeansincludesanoutputgearwhilethesecondsidegearmeansincludesashaftwhichextendsrearwardlytotherearwardreardriveaxletoprovidepowerthereto.Afirstgearisindrivingengagementwiththeoutputgearassociatedwiththefirstdifferentialsidegeartobecapableofdrivingashaftwhichisoperablycoupledtotheforwardlypositionedreardriveaxle.Asecondgearmeansisindrivingengagementwiththefirstgearmeanstoprovidepowertoashaftwhichextendsforwardlyfordrivingthefrontdriveaxle.Thereisincludedmeansforselectivelycouplinganduncouplingtheforwardlyextendingshaftfordrivingthefrontdriveaxlefromthesecondgearmeanstoselectivelyallowthedrivesystemtobeoperatedineitherthe6x6orthe6x4mode.U.S.PatentNumber4,050,534includesaexplanationofhowthedriveaxlesystemdisclosedthereinwilloperateundera"idealoperatingcondition".Inthis"idealoperatingcondition",theinputpowerwouldbeequallydividedinthedifferentialgearsettoprovideapproximatelyfiftypercentofpowertoeachofthedifferentialside-gears.Withoneofthedifferentialsidegearsbeingutilizedtoprovidepowertoboththefrontdriveaxleandoneofthereardriveaxles,theoverallpowerdistributionunderthis"idealoperatingcondition"wouldresultinthefrontdriveaxleprovidingapproximatelytwenty-fivepercentofthepowerneededtodrivethevehiclewhiletheforwardlypositionedreardriveaxleprovidedapproximatelytwenty-fivepercentandtherearwardreardriveaxletheremainingfiftypercent.Whilethis"idealoperatingcondition"mightreasonablyconformtomostloadingconditionsforthevehicle,therearesome"worstcase"situationswhichcastdoubtontheacceptabilityandreliabilityoftheconfigurationdisclosedthereinTheexplanationofthepowerloadingforthedriveaxlesystemisbasicallyaccurateforthe"idealoperatingcondition"inwhichtheloadisrelativelyevenlydistributed,thevehicleisoperatingonalevelsurface,andeachofthewheelsismakingnon-slipping,frictionalcontactwiththedrivingsurface.However,ifthecontactwiththedrivingsurfaceisunsatisfactoryforoneormoreoftheaxles,asexplainedinU.S.PatentNumber4,050,534,itisnotuncommonforsuchadriveaxlesystemtoincludeameansfor"lockingout"theinteraxledifferentialtopreventawheelorpairofwheelsonaslipperysurfacefromreceivingallofthetorquefromtheinteraxledifferentialandpreventingeffectivemovementofthevehicle.Insuchacondition,itwouldbepossiblefortheoutputgeartobereceivingsubstantiallyalloftheinputtorqueiftherearwardrearaxleassociatedwiththeseconddifferentialsidegearwerenotmakinggoodcontactwiththedrivingsurfaceand,therefore,incapableofactuallyprovidingpowerformovingthevehicle.Withtheoutputgearreceivingsubstantiallyalloftheinputtorque,itwouldallbetransmittedtotheremainingtwoaxles.TheresultingloadontheoutputgearintheconfigurationastaughtinU.S.PatentNumber4,050,534wouldbesignificantandmightunnecessarilystrainorweakentheteeththereon.WhilethedriveaxlesystemdisclosedinU.S.PatentNumber4,050,534mightbesatisfactoryforanumberofvehicleinstallations,thedirectcouplingofthesecondgearwhichdrivesthefrontdriveaxletothefirstgearwhichdrivestheforwardlypositionedrearaxledoespresentaconfigurationwhichlimitsthepossibledesignlocationoftheforwardlyextendingoutputshaftfordrivingthefrontdriveaxle.Thelocationoftheoutputshaftfordrivingthefrontdriveaxlecanbesignificantinsomevehicleswherehighergroundclearanceisdesiredorwherethereisaneedtoavoidtheengineortransmissionandprovideclearancebetweentheengineortransmissionandtheoutputshaftextendingforwardlytopowerthefrontdriveaxle.SummaryoftheInventionItis,therefore,anobjectofthisinventiontoprovideanimprovedtandemdriveaxlesystemwhichisreliableandcapableofbeingdesignedtoaccommodatespecialvehicleconfigurations.Theseandotherobjectsoftheinventionareprovidedinapreferredembodimentthereofwhichincludesanimprovedtandemdriveaxlesystemofthetypewhichiscapableofreceivinginputtorquefromavehiclepowersourceandtransmittingthetorquetofirstandsecondreardriveaxlesandafrontdriveaxle.Thereisalsoincludedmeansfordividingtheinputtorquethroughadifferentialgearsethavingfirstandseconddifferentialsidegears.Eachofthesidegearstransmitsoutputtorqueofamagnitudewhichissubstantiallyone-halfoftheinputtorqueunderidealoperatingconditions.Thefirstdifferentialsidegearincludesanoutputgearindrivingengagementwithafirstgearmeansfortransmittingatleastaportionoftheoutputtorquefromthefirstdifferentialsidegeartothefirstreardriveaxle.Theseconddifferentialsidegearisoperablycoupledtothesecondreardriveaxlefortransmissionoftheoutputtorquefromtheseconddifferentialsidegear.Theimprovementincludesanidlergearmeansindrivingengagementwiththeoutputgearandasecondgearmeansindrivingengagementwiththeidlergearmeanstobecapableoftransmittingaremainderoftheoutputtorqueofthefirstdifferentialsidegearfromtheoutputgearthroughtheidlergearmeanstotheforwarddriveaxleshaft.Thereisalsoincludedmeansforselectivelycouplingthesecondgearmeanstothefrontdriveaxlefortransmittingtheremainderoftheoutputtorquetheretoandforuncouplingthesecondgearmeansfromthefrontdriveaxletoallowfreerunningoftheidlergearmeansandsecondgearmeans.BriefDescriptionoftheDrawingsFigure1isaschematictopplanviewshowingthedriveaxlesystemofthepresentinventionasitwouldappearina6x6vehicle.Figure2isaschematicviewofthedriveaxlesystemasitwouldgenerallyappearalongtheline2-2ofFigure1.Figure3isaviewpartiallyinsectionofapreferredembodimentoftheinventionaswouldgenerallybeseenalongline3-3ofFigure2.DescriptionofthePreferredEmbodimentAsseeninFigure1,aschematicviewofa6x6vehicle10includesvariousfeaturesofthedriveaxlesystemofthepresentinvention.Thevehiclepowersource12includesanengineandtransmissionandhasadriveshaft16whichextendsrearwardlytherefrom.Thedriveshaft16iscoupledtoashaftwithinainteraxledifferentialhousing18whichisphysicallyassociatedwiththeforwardlypositionedrearaxle20ofapairoftandemreardriveaxles20,22.Inthepreferredembodiment,theinteraxledifferentialhousing18basicallyincludesthecomponentswhichareutilizedtodivideandtransferthepowertothevariousmembersofthedriveaxlesystem.Theinteraxledifferentialwithinthehousing18dividesasingleinputtorqueandsuppliesaportionofitsoutputpowerthroughanaxledifferentialtotheforwardlypositionedrearaxle20.Aseconddriveshaft24receivestheremainingoutputtorqueandextendsrearwardlyfromtheinteraxledifferentialwithinthehousing18todriveanotheraxledifferential26oftherearwardlypositionedrearaxle22.Toprovidepowertoafrontsteering,driveaxle28forthevehicle10,athirddriveshaft30extendsforwardlyfromtheinteraxledifferentialhousing18tobecoupledwithyetanotheraxledifferential32oftheforwarddriveaxle28.Asthusdescribed,powercanbeprovidedfromthepowersource12totheinteraxledifferentialwithinthehousing18which,aswillbeexplainedindetailhereinbelow,iscapableofdividingtheinputpowertoprovideanoutputpowertoeachoftheaxles20,22and28whenthevehicleisbeingoperatedina6x6mode.Aswillalsobeseen,thereisincludedmeansassociatedwiththevehicledrivesystemofthepresentinventionforuncouplingthethirddriveshaft30topreventpowerfrombeingappliedtothefrontdriveaxle28sothatthevehiclecouldbeoperatedina6x4mode.AsseeninFigures2and3,theinteraxledifferentialhousing18includesthemajorelementsofthepresentinventionwhichdivideandtransmitpowertothevariousaxles.Specifically,aninputshaft34ismountedforrotationwithintheinteraxledifferentialhousing18atbearings36andincludesacoupling38towhichthedriveshaft16(notshown)isjoined.Aninteraxledifferentialgearset40ismountedattherearwardendoftheinputshaft34andincludesadifferentialcageandspider42whichisrigidlycoupledtotheshaft34.Thedifferentialcageandspider42includespiniongears44whicharecapableoftransmittingpowertoafirstdifferentialsidegear46andaseconddifferentialsidegear48.Thedifferentialsidegear46ismountedontheinputshaft34andiscapableofindependentrelativerotationthereon.Similarly,theseconddifferentialsidegear48ismountedontheinputshaft34tobecapableofindependentrelativerotationthereonandisbasicallysupportedbybearings50whichalsoservetosupporttherearendoftheinputshaft32becauseofthemannerinwhichthesidegear48receivestherearendoftheinputshaft34therein.Theseconddifferentialsidegear48isrigidlyjoinedtoarearwardlyextendingshaftmeans48whichextendsfromtherearoftheinteraxledifferentialhousing18tobetherecoupledwiththesecondrearwardlyextendingdriveshaft24(notshown).Accordingly,powerreceivedattheseconddifferentialsidegear48iscapableofprovidingpowertotherearwardlypositionedrearaxle22inthemannerdescribedhereinabove.Thefirstdifferentialsidegear46includesatitsforwardendanoutputgear54whichiscapableoftransmittingtheoutputpowerreceivedbythefirstdifferentialsidegear46.Totransmitaportionoftheoutputpowerfromthefirstdifferentialsidegear46tobytheforwardlypositionedrearaxle20,afirstgear56.isalignedwithandinengagingcontactwiththeoutputgear54.Thefirstgear56isrigidlymountedonashaft58whichis,inturn,mountedforrotationatbearings60withintheinterioroftheinteraxledifferentialhousing18.Aninputpinion62ismountedattherearwardendoftheshaft58andisinengagingcontactwithadifferentialringgear64whichdrivesanaxledifferentialmechanism(notshown)forprovidingtheoutputtorquetotheforwardlypositionedreardriveaxle20.Asthusdescribed,theinputtorquefromthepowersource12iscapableofbeingsuppliedtotherearaxles20and22asitisbeingdividedbytheinteraxledifferentialgearset40.Specifically,underanidealoperatingconditioninwhichthevehicleisoperatingonarelativelylevelsurfacewithagenerallyevenlydistributedloadonthevariousaxles,theoutputtorqueateachofthedifferentialsidegear46,48wouldbeaboutone-halfoftheinputtorquereceivedfromthepowersource12.Ifthevehicleweretobeoperatingina6x4mode,thedriveaxlesystemasthusdescribedwouldbeoperatinginamannerwellknownintheartwiththeinteraxledifferential40basicallydividingalloftheloadbetweenthetworeartandemaxles20and22.Theinteraxledifferential40isconsiderednecessarybecauseoftherealpossibilitythattheloadinactualoperationwouldnotbeevenlydistributedbetweenthetwoaxlesandtheinteraxledifferentialwouldstillenablethevehicletooperatewhileallowingsomeslippageorvaryingtactionconditionsbetweenthetwoaxles20,22.However,asisalsowellknowninthedriveaxleart,thereareoccasionswhenthedifferentiationprovidedbytheinteraxledifferential40isnotdesired.Sinceitispossibleforthewheelsassociatedwithoneoftheaxles20,22tobeinsuchanon-tractionconditionthatnopowercouldbeappliedtothedrivingsurfaceforthemovementofthevehicle,thereisquiteoftenincludedmeansfor"lockingout"thedifferentialtoinsurethatbothaxlesmovesimultaneouslyandthateitheraxlemakingsufficientcontactwiththedrivingsurfacewouldbecapableofpropellingthevehicle.Toaccomplishthis,aclutchmeans66ismountedontheinputshaft34onasetofoutwardlyextendingteeth67thereof.AsshowninFigure3,theclutchmeans66isforwardlypositionedsothatitis,infact,notaffectingthedifferentiationwhichisprovidedbytheinteraxledifferential40.However,inordertoachievethe"lockout"conditiontopreventdifferentiation,thereismeansintheformofashiftrodandfork(notshown)whichcanactonthecircumferentialgroove68oftheclutchmeans66tocauseittobemovedaxiallyrearwardlyontheteeth67oftheinputshaft34.Whentheclutchmeans66ismovedsufficientlyrearwardly,itisbroughtintoalignmentwithandengagesasetofgearteeth70ontheforwardendofthefirstdifferentialsidegear46tocouplethefirstdifferentialsidegear46directlytotheinputshaft34.Whenthefirstdifferentialsidegear46issocoupledtotheinputshaft34,therewouldbenofurtherdifferentiationandtheinputtorquewouldthenbetransmittedeitherthroughtheoutputgear54ortherearwardlyextendingshaft52accordingtotheresistancecreatedbyeachrearaxle20,22aseachmakescontactwiththedrivingsurface.Asmentionedhereinabove,thepresentinventionandthedriveaxlesystemdisclosedinU.S.PatentNumber4,050,534bothincludemeanswithinthedifferentialhousing18forprovidingoutputtothefrontdriveaxle28.InU.S.PatentNumber4,050,534thisisaccomplishedbytherebeinganadditionalgearindrivingengagementwiththefirstgear56sothattheoutputtorquereceivedattheoutputgear54willbecapableofprovidingpowertoboththefrontdriveaxle28andtheforwardlypositionedreardriveaxle20.Asaresult,allofthepowerwhichistransmittedtothesetwoaxleswillbespecificallytransmittedatasingleengagingcontactpointbetweentheoutputgear54andthefirstgear58.However,inaworstcasesituation,therecouldbesufficientslippageintherearwardlypositionedrearaxle22fortheoperatorofthevehicletocausetheclutchmeans66tobeutilizedtopreventdifferentiationbytheinteraxledifferential40.Ifthevehicleisheavilyloadedandthereisexcellentroadtractionforthefrontdriveaxle28andtheforwardlypositionedrearaxle20,alloftheinputpowerfromthepowersourcewouldbetransmittedtothesetwoaxlesthroughthesingleoutputgear54.Althoughthiswouldnotbeanormaloperatingcondition,itwouldnotbeunusualforthishighloadingsituationtoperiodicallyoccur.Theresultingstressandwearontheteethoftheoutputgear54attheirsingleengagingcontactpointwiththefirstgear56couldbesignificantandadverselytoaffecttheoverallreliabilityandlifeofthedriveaxlesystemAccordingly,inthepreferredembodiment,toprovidepowertothefrontdriveaxle28thereisincludedaidlergear72whichisinengagingcontactwiththeoutputgear54butatalocationthereonwhichiscircumferentiallyspacedfromthepointofengagementwiththefirstgear56.Theidlergear72isrigidlymountedonanidlershaft74whichismountedforrotationonbearings76withintheinteraxledifferentialhousing18.Toprovidepowerforthefrontdriveaxle28,thereisincludedasecondgear78whichengagestheidlergear72sothatbothgears72,78willrotateinresponsetorotationoftheoutputgear54.Thesecondgear78ismountedonashaft80andiscapableofindependentrelativerotationthereon.Theshaft80ismountedwithintheinteraxledifferentialhousing18atbearings82andincludesaforwardendwhichiscapableofbeingcoupledtotheforwardlyextendingdriveshaft30forprovidingpowertothefrontdriveaxle28.Thesecondgear78isnotrigidlymountedontheshaft80inthepreferredembodimentoftheinventioninordertoincludeameansforselectivelytransmittingpowertothefrontdriveaxle28.Thisisaccomplishedinamannerwellknowninthepowertransmittingartintheformofaclutch84whichissimilarinfunctionandoperationtotheclutchmeans66describedhereinabove.Theclutch84ismountedonoutwardlyextendingteeth85oftheshaft80andcanbeselectively,rearwardlypositionedtoengageoutwardlyextendingteeth86onthesecondgear78torigidlycouplethesecondgear78totheshaft80forthetransmissionofpowertothefrontdriveaxle28whenthe6x6modeofoperationisdesired.Relocatingtheclutch84toaforwardpositionwoulduncouplethesecondgear78fromtheshaft80andallowtheidlergear72andthesecondgear78torunfreelywithoutanytransmissionofpowertothefrontdriveaxle28andthusreturnthevehicletothe6x4modeofoperation.However,withtheconfigurationutilizedinthepresentinvention,ifthevehicleweretoagainbeoperatinginaworstcasesituationwiththeinteraxledifferential"lockedout",thepowerbeingtransmittedtotheaxle28a