外文翻譯--黏性連接器用作前輪驅(qū)動(dòng)限制滑移差速器對(duì)汽車牽引和操縱的影響

1、<p>　　畢業(yè)設(shè)計(jì)(論文)外文資料翻譯</p><p>　　系　　部： 機(jī)械工程系 </p><p>　　專 業(yè)： 機(jī)械工程及自動(dòng)化 </p><p>　　姓 名： </p><p>　　學(xué)

2、 號(hào)： </p><p>　　外文出處：The Effect of a Viscous Coupling Used as a </p><p>　　Front-Wheel Drive Limited-Slip Differential </p><p>　　o

3、n Vehicle Traction and Handling </p><p>　　附 件：1.外文資料翻譯譯文；2.外文原文。 </p><p>　　附件1：外文資料翻譯譯文</p><p>　　黏性連接器用作前輪驅(qū)動(dòng)限制滑移差速器對(duì)汽車牽引和操縱的影響</p><p>&l

4、t;b>　　1基本概念</b></p><p>　　黏性連接器主要地被認(rèn)為是在四輪驅(qū)動(dòng)的汽車上驅(qū)動(dòng)路線的一部件。然而，在近些年的發(fā)展中，施用在前輪驅(qū)動(dòng)的趨勢(shì)中將成為重要角色的觀點(diǎn)是可能的。在歐洲和日本前輪驅(qū)動(dòng)轎車產(chǎn)量的施用已經(jīng)證明黏性連接器不僅對(duì)于光滑路面的汽車牽引，而且在正常行駛條件下對(duì)于操縱性和穩(wěn)定性都有所改善。</p><p>　　這篇文章展示出調(diào)查黏性連接器對(duì)汽車

5、牽引和操縱的影響的重大檢驗(yàn)場(chǎng)試驗(yàn)，試驗(yàn)證明大多數(shù)牽引的改善僅僅輕微地影響轉(zhuǎn)向裝置的扭轉(zhuǎn)力。前輪驅(qū)動(dòng)的汽車在直線行駛時(shí)影響發(fā)動(dòng)機(jī)轉(zhuǎn)矩的因素被描述出來(lái)。在前輪驅(qū)動(dòng)的汽車上極大地影響限制滑移差速器適合性的關(guān)鍵汽車設(shè)計(jì)參數(shù)被確定。</p><p>　　轉(zhuǎn)彎試驗(yàn)展現(xiàn)出黏性連接器在前輪驅(qū)動(dòng)的汽車上獨(dú)立轉(zhuǎn)彎時(shí)的影響。進(jìn)一步的試驗(yàn)證明安裝黏性限制滑移差速器的汽車在加速和轉(zhuǎn)彎時(shí)節(jié)氣門頻繁關(guān)閉的 情況下顯示出一個(gè)改善的穩(wěn)定性。<

6、;/p><p><b>　　2 黏性連接器</b></p><p>　　黏性連接器被廣泛認(rèn)為是驅(qū)動(dòng)列車的一組成部件。在這篇文章中僅僅給出它的基本功能和原理的簡(jiǎn)明概要。</p><p>　　黏性連接器是根據(jù)液體摩擦的原理和依靠速度差來(lái)運(yùn)轉(zhuǎn)的。正如圖1所示黏性連接器的滑動(dòng)控制特性和驅(qū)動(dòng)觀察系統(tǒng)的對(duì)比。</p><p>　　這表明

7、傳送到前輪的驅(qū)動(dòng)扭轉(zhuǎn)力是由一個(gè)優(yōu)化的扭轉(zhuǎn)力分配檢測(cè)器自動(dòng)控制的。</p><p>　　在前輪驅(qū)動(dòng)的汽車上黏性連接器可以安裝在差速器的內(nèi)側(cè)或者一根中間軸的外面。外面的方式如圖2所示。</p><p>　　內(nèi)部的這種設(shè)計(jì)方式有很大的優(yōu)點(diǎn)。首先，在中間軸區(qū)域可以得到足夠的空間來(lái)提供符合要求的黏性特性。這和當(dāng)今前輪軸差速器只留下有限的空間相對(duì)比。其次，差速器架和轉(zhuǎn)送軸套只需要很小的修改。而且差速器

8、殼體的生產(chǎn)也僅僅只有一點(diǎn)影響。引用作為一個(gè)選擇性的事很容易做到尤其當(dāng)軸和黏性單元作為一個(gè)整體單元被共給時(shí)。最后，中間軸使為等長(zhǎng)的的側(cè)偏軸提供橫向安裝發(fā)動(dòng)機(jī)是可能的，橫向地安裝發(fā)動(dòng)機(jī)對(duì)于減小扭轉(zhuǎn)力的操縱是很重要的（后面第四部分說(shuō)明了）。</p><p>　　這種特殊的設(shè)計(jì)也為有實(shí)際意義的重量和黏性單元費(fèi)用的降低給出了很好的可能性。GKN Viscodrive正在發(fā)展一種低重量和低成本的黏性連接器。通過(guò)使用僅僅兩個(gè)標(biāo)

9、準(zhǔn)化的直徑、標(biāo)準(zhǔn)化的盤，塑料輪轂和擠壓成型的材料造成的儲(chǔ)存室它能很容易地被截成不同的長(zhǎng)度，使用一個(gè)寬的黏性范圍是可能的。在圖3中顯示出這種發(fā)展的一個(gè)例子。</p><p><b>　　3 牽引力的影響</b></p><p>　　作為一個(gè)扭轉(zhuǎn)力平衡裝置，一個(gè)開(kāi)的差速器提供相等的力到兩個(gè)驅(qū)動(dòng)輪上。它也允許每個(gè)車輪在扭轉(zhuǎn)沒(méi)結(jié)束轉(zhuǎn)彎時(shí)以不同的速度轉(zhuǎn)動(dòng)。然而，這種特性當(dāng)?shù)缆繁?/p>

10、面滑動(dòng)系數(shù)為限制扭轉(zhuǎn)力傳遞到兩輪的左、右附著變動(dòng)時(shí)是不利的，它能被低滑動(dòng)系數(shù)的輪子支持。</p><p>　　安裝黏性限制滑移差速器,在高的值的路面上它可能利用高車輪附著潛在性.這在圖4中顯示出。</p><p>　　例如，當(dāng)一個(gè)車輪傳遞的最大扭轉(zhuǎn)力超出表面滑動(dòng)系數(shù)允許值或者以一個(gè)高的側(cè)面加速度轉(zhuǎn)彎時(shí)，兩個(gè)車輪的速度是不同的.在黏性連接器中產(chǎn)生的自鎖扭轉(zhuǎn)力抵抗速度差的增加并且傳遞合適的扭轉(zhuǎn)

11、力到車輪上它具有更好的牽引力潛能。</p><p>　　在圖4中可以看出牽引力的不同導(dǎo)致汽車瞬間向低滑動(dòng)系數(shù)值()一側(cè)跑偏，為了保持汽車直線行駛駕駛員必須施加一個(gè)相反的扭轉(zhuǎn)力來(lái)補(bǔ)償。通過(guò)黏性連接器的液體摩擦原理和從打開(kāi)到鎖死柔和的傳遞結(jié)果,這是很可能的，從汽車實(shí)驗(yàn)中得到的合適結(jié)果如圖5所示。</p><p>　　報(bào)告稱平均操縱輪扭轉(zhuǎn)力和為保持帶有一個(gè)開(kāi)式的并且黏性的差速器在加速期間在滑動(dòng)系

12、數(shù)的路面上直線行駛應(yīng)輸入的平均正確的相對(duì)的轉(zhuǎn)向操縱。相互對(duì)照開(kāi)式差速器和那些黏性連接器是相對(duì)大的。然而，在絕對(duì)條件下它們是小的。主觀地說(shuō)，轉(zhuǎn)向裝置的影響是不明顯的。扭轉(zhuǎn)力操縱也受幾個(gè)運(yùn)動(dòng)參數(shù)影響這些參數(shù)將在這篇文章下個(gè)部分解釋。</p><p>　　4 影響轉(zhuǎn)向裝置扭轉(zhuǎn)力的因素</p><p>　　如圖6所示牽引力引起一個(gè)從頭到尾的增加來(lái)反應(yīng)每個(gè)車輪。因?yàn)閹в邢拗苹瑒?dòng)差速器的車輪在滑動(dòng)系數(shù)

13、的路面上加速時(shí)會(huì)出現(xiàn)不同的牽引力，所以從頭到尾反應(yīng)每個(gè)車輪的變化也是不同的。</p><p>　　不幸的是，這個(gè)作用將導(dǎo)致一個(gè)不期望的朝低滑動(dòng)系數(shù)一側(cè)的反應(yīng)，也就是說(shuō)在不同的牽引力下產(chǎn)生相同的跑偏方向。</p><p>　　降低從頭到尾的彈力是黏性限制滑動(dòng)差速器像其它任何形式差速器一樣在前軸的成功應(yīng)用所必須具備的。</p><p>　　普遍地用下面的公式計(jì)算一個(gè)車輪

14、的驅(qū)動(dòng)力</p><p><b>　　—牽引力</b></p><p><b>　　—車輪垂直載荷</b></p><p><b>　　—利用的附著系數(shù)</b></p><p>　　這些驅(qū)動(dòng)力導(dǎo)致在車輪之間每個(gè)車輪的轉(zhuǎn)向裝置扭轉(zhuǎn)力經(jīng)過(guò)車輪干擾常數(shù)e干擾后與每個(gè)車輪的轉(zhuǎn)向裝置扭

15、轉(zhuǎn)力是不同的，給出下面的等式。</p><p>　　這里 —扭轉(zhuǎn)力矩差值</p><p><b>　　e—車輪干擾常數(shù)</b></p><p><b>　　— 主銷傾角</b></p><p>　　—高滑動(dòng)系數(shù)一側(cè)下標(biāo)</p><p>　　—低滑動(dòng)系數(shù)一側(cè)下標(biāo)</p&g

16、t;<p>　　在帶有開(kāi)式差速器前輪驅(qū)動(dòng)汽車的情況下，是很不明顯的，因?yàn)榕まD(zhuǎn)力基數(shù)是不大于1.35的。</p><p>　　然而，因?yàn)閼?yīng)用了限制滑動(dòng)差速器，這個(gè)影響是很有意義的。這樣車輪干擾常數(shù)e就應(yīng)該盡可能的小。不同的車輪載荷也會(huì)導(dǎo)致的增加所以差別也要盡可能的小。</p><p>　　當(dāng)扭轉(zhuǎn)力通過(guò)鉸接“CV連接”傳遞時(shí)，在主動(dòng)一側(cè)（下標(biāo)1）和從動(dòng)一側(cè)（下標(biāo)2），必須反應(yīng)垂直

17、平面相對(duì)于連接平面的不同的第二個(gè)力矩產(chǎn)生了。第二個(gè)力矩（M）大小和方向用于下面的式子計(jì)算（如圖8）：</p><p><b>　　主動(dòng)一側(cè)</b></p><p><b>　　從動(dòng)一側(cè) </b></p><p><b>　　這里 —縱向連接角</b></p><p>　　—產(chǎn)生

18、的連接角 </p><p>　　—產(chǎn)生變化的輪子半徑</p><p><b>　　—平均扭轉(zhuǎn)力矩?fù)p失</b></p><p>　　當(dāng)每個(gè)裝置的轉(zhuǎn)向扭轉(zhuǎn)力以及輪子之間的轉(zhuǎn)向裝置扭轉(zhuǎn)力不同時(shí)，將圍繞著主銷軸線變動(dòng)，如下所示：</p><p>　　這里 —轉(zhuǎn)向裝置扭轉(zhuǎn)力矩差</p>

19、<p><b>　　W—輪子一側(cè)的下標(biāo)</b></p><p>　　因此很明顯不僅不同的驅(qū)動(dòng)扭轉(zhuǎn)力而且黏性驅(qū)動(dòng)軸長(zhǎng)度的不同也是一個(gè)因素。說(shuō)道圖7中的力矩多邊形，的旋轉(zhuǎn)方向或者各自地變化，都取決于輪子中心到變速箱輸出的位置。</p><p>　　如圖7所示由于半軸的正常位置（輪子中心低于變速箱的輸出點(diǎn)）第二個(gè)力矩產(chǎn)生和驅(qū)動(dòng)力一樣的旋轉(zhuǎn)方向。由于改進(jìn)的懸掛裝

20、置設(shè)計(jì)（車輪中心高于變速箱輸出點(diǎn)，也就是說(shuō)，為負(fù)值）第二個(gè)力矩抵消了由驅(qū)動(dòng)力引起的力矩。這樣為了得到帶一個(gè)限制滑動(dòng)差速器前軸好的適應(yīng)性，設(shè)計(jì)要求：1）縱向彎曲角近似或者負(fù)值（）且左側(cè)和右側(cè)的值相等；2）等長(zhǎng)度的側(cè)軸。</p><p>　　第二力矩在轉(zhuǎn)向裝置的影響不僅僅是上面描述的限制直接反應(yīng)。從連接軸到車輪側(cè)面和變速箱側(cè)面之間的連接點(diǎn)間接反應(yīng)也會(huì)產(chǎn)生，如下所示：</p><p>　　圖表9

21、：由縱向平面的半軸連接產(chǎn)生的間接反應(yīng)</p><p>　　因?yàn)榕まD(zhuǎn)力傳遞沒(méi)有損失并且兩個(gè)在連接軸上的第二個(gè)力矩都相互補(bǔ)償。然而，事實(shí)上（有扭轉(zhuǎn)力損失），第二個(gè)力矩出現(xiàn)不同：</p><p>　　第二個(gè)力矩不同點(diǎn)是：</p><p><b>　　為了簡(jiǎn)化應(yīng)用給出和</b></p><p>　　需要在兩個(gè)連接處都有抵抗反應(yīng)的

22、力這里</p><p>　　。由連接處引起的干擾常數(shù)f，一個(gè)附加的轉(zhuǎn)向裝置扭轉(zhuǎn)力矩也圍繞著主銷軸線變動(dòng)：</p><p>　　這里 —每個(gè)車輪的轉(zhuǎn)向裝置扭轉(zhuǎn)力矩</p><p>　　—轉(zhuǎn)向裝置扭轉(zhuǎn)力矩差</p><p><b>　　f—連接處干擾系數(shù)</b></p><p>　　L—連接軸（

23、半軸）的長(zhǎng)度</p><p>　　由于f值小，理想值是0，的影響較小。</p><p>　　黏性聯(lián)結(jié)器前驅(qū)動(dòng)的汽車沒(méi)有ABS（制動(dòng)防抱死系統(tǒng)）在滑動(dòng)系數(shù)為的路面上制動(dòng)時(shí)僅僅具有一個(gè)非常小的影響。因此前輪被部分的聯(lián)結(jié)通過(guò)低值的一側(cè)的前輪比安裝有開(kāi)式差速器的汽車稍稍高一些。在另一側(cè)，在高值一側(cè)被制動(dòng)壓力鎖著的前輪要稍稍的低一些。這些差值可以用一個(gè)裝有儀器的試驗(yàn)汽車測(cè)著但是靠主觀的評(píng)定幾乎是不明

24、顯的。前軸和后軸的鎖止有持續(xù)的行動(dòng)不受黏性聯(lián)結(jié)器的影響。</p><p>　　現(xiàn)代提供的大多數(shù)ABS能夠單獨(dú)地控制每一個(gè)前輪。前輪驅(qū)動(dòng)汽車的電子ABS必須考慮到相當(dāng)多的在制動(dòng)之間有效的車輪慣性的差別隨著離合器的嚙合和分離。</p><p>　　前輪的部分聯(lián)結(jié)器通過(guò)黏性單元不這樣因此修改ABS行為的事實(shí)已經(jīng)被無(wú)數(shù)個(gè)實(shí)驗(yàn)和幾個(gè)獨(dú)立的轎車生產(chǎn)廠家證明。一個(gè)理念的希望是這發(fā)生在一個(gè)滑動(dòng)系數(shù)為的表面

25、上，如果一個(gè)側(cè)偏力矩推遲產(chǎn)生或者側(cè)偏力矩降低（YMR）就可以得出ABS控制單元。如圖表18所示帶有和沒(méi)有YMR典型的制動(dòng)壓力的有秩序的行動(dòng)。</p><p>　　如圖表18：裝ABS的汽車在滑動(dòng)系數(shù)為的路面上制動(dòng)時(shí)前輪制動(dòng)產(chǎn)生的制動(dòng)壓力和生成特性</p><p>　　對(duì)于低偏側(cè)慣性和短軸矩的汽車，側(cè)偏力矩的產(chǎn)生可以被推遲從而允許正常的駕駛員有足夠的反應(yīng)時(shí)間依靠ABS為高值的車輪降低制動(dòng)力的

26、產(chǎn)生。尤其在剛開(kāi)始制動(dòng)時(shí)，因此在高摩擦系數(shù)路面上的車輪，在制動(dòng)狀態(tài)下和行駛時(shí)很少滑移。對(duì)比之下，低值的車輪，能同時(shí)通過(guò)黏性差速器引起速度差產(chǎn)生一個(gè)很大的滑移。結(jié)果當(dāng)在高值的車輪上產(chǎn)生抵抗YMR的額外制動(dòng)力時(shí)自鎖扭轉(zhuǎn)力出現(xiàn)了。</p><p><b>　　附件2：外文原文</b></p><p>　　The Effect of a Viscous Coupling Us

27、ed as a Front-Wheel Drive Limited-Slip Differential on Vehicle Traction and Handling</p><p>　　1 ABCTRACT</p><p>　　The viscous coupling is known mainly as a driveline component in four wheel driv

28、e vehicles. Developments in recent years, however, point toward the probability that this device will become a major player in mainstream front-wheel drive application. Production application in European and Japanese fro

29、nt-wheel drive cars have demonstrated that viscous couplings provide substantial improvements not only in traction on slippery surfaces but also in handing and stability even under normal driving cond</p><p>

30、;　　This paper presents a serious of proving ground tests which investigate the effects of a viscous coupling in a front-wheel drive vehicle on traction and handing. Testing demonstrates substantial traction improvements

31、while only slightly influencing steering torque. Factors affecting this steering torque in front-wheel drive vehicles during straight line driving are described. Key vehicle design parameters are identified which greatly

32、 influence the compatibility of limited-slip differentials in f</p><p>　　Cornering tests show the influence of the viscous coupling on the self steering behavior of a front-wheel drive vehicle. Further testi

33、ng demonstrates that a vehicle with a viscous limited-slip differential exhibits an improved stability under acceleration and throttle-off maneuvers during cornering.</p><p>　　2 THE VISCOUS COUPLING</p>

34、;<p>　　The viscous coupling is a well known component in drivetrains. In this paper only a short summary of its basic function and principle shall be given.</p><p>　　The viscous coupling operates acco

35、rding to the principle of fluid friction, and is thus dependent on speed difference. As shown in Figure 1 the viscous coupling has slip controlling properties in contrast to torque sensing systems.</p><p>　　

36、This means that the drive torque which is transmitted to the front wheels is automatically controlled in the sense of an optimized torque distribution.</p><p>　　In a front-wheel drive vehicle the viscous cou

37、pling can be installed inside the differential or externally on an intermediate shaft. The external solution is shown in Figure 2.</p><p>　　This layout has some significant advantages over the internal solut

38、ion. First, there is usually enough space available in the area of the intermediate shaft to provide the required viscous characteristic. This is in contrast to the limited space left in today’s front-axle differentials.

39、 Further, only minimal modification to the differential carrier and transmission case is required. In-house production of differentials is thus only slightly affected. Introduction as an option can be made easily </p&

40、gt;<p>　　This special design also gives a good possibility for significant weight and cost reductions of the viscous unit. GKN Viscodrive is developing a low weight and cost viscous coupling. By using only two sta

41、ndardized outer diameters, standardized plates, plastic hubs and extruded material for the housing which can easily be cut to different lengths, it is possible to utilize a wide range of viscous characteristics. An examp

42、le of this development is shown in Figure 3.</p><p>　　3 TRACTION EFFECTS</p><p>　　As a torque balancing device, an open differential provides equal tractive effort to both driving wheels. It all

43、ows each wheel to rotate at different speeds during cornering without torsional wind-up. These characteristics, however, can be disadvantageous when adhesion variations between the left and right sides of the road surfac

44、e (split-μ) limits the torque transmitted for both wheels to that which can be supported by the low-μ wheel.</p><p>　　With a viscous limited-slip differential, it is possible to utilize the higher adhesion p

45、otential of the wheel on the high-μsurface. This is schematically shown in Figure 4.</p><p>　　When for example, the maximum transmittable torque for one wheel is exceeded on a split-μsurface or during corner

46、ing with high lateral acceleration, a speed difference between the two driving wheels occurs. The resulting self-locking torque in the viscous coupling resists any further increase in speed difference and transmits the a

47、ppropriate torque to the wheel with the better traction potential.</p><p>　　It can be seen in Figure 4 that the difference in the tractive forces results in a yawing moment which tries to turn the vehicle in

48、 to the low-μside, To keep the vehicle in a straight line the driver has to compensate this with opposite steering input. Though the fluid-friction principle of the viscous coupling and the resulting soft transition from

49、 open to locking action, this is easily possible, The appropriate results obtained from vehicle tests are shown in Figure 5.</p><p>　　Reported are the average steering-wheel torque Ts and the average correct

50、ive opposite steering input required to maintain a straight course during acceleration on a split-μtrack with an open and a viscous differential. The differences between the values with the open differential and those wi

51、th the viscous coupling are relatively large in comparison to each other. However, they are small in absolute terms. Subjectively, the steering influence is nearly unnoticeable. The torque steer is also infl</p>&

52、lt;p>　　4 FACTORS AFFECTING STEERING TORQUE</p><p>　　As shown in Figure 6 the tractive forces lead to an increase in the toe-in response per wheel. For differing tractive forces, Which appear when accelera

53、ting on split-μwith limited-slip differentials, the toe-in response changes per wheel are also different.</p><p>　　Unfortunately, this effect leads to an undesirable turn-in response to the low-μside, i.e. t

54、he same yaw direction as caused by the difference in the tractive forces.</p><p>　　Reduced toe-in elasticity is thus an essential requirement for the successful front-axle application of a viscous limited-sl

55、ip differential as well as any other type of limited-slip differential.</p><p>　　Generally the following equations apply to the driving forces on a wheel</p><p>　　With Tractive Force</p>

56、<p>　　Vertical Wheel Load</p><p>　　Utilized Adhesion Coefficient</p><p>　　These driving forces result in steering torque at each wheel via the wheel disturbance level arm “e” and a steering

57、 torque difference between the wheels given by the equation:</p><p><b>　　△=</b></p><p>　　Where △Steering Torque Difference</p><p>　　e=Wheel Disturbance Level Arm

58、</p><p>　　King Pin Angle</p><p>　　hi=high-μside subscript</p><p>　　lo=low-μside subscript</p><p>　　In the case of front-wheel drive vehicles with open differentials, △T

59、s is almost unnoticeable, since the torque bias () is no more than 1.35.</p><p>　　For applications with limited-slip differentials, however, the influence is significant. Thus the wheel disturbance lever arm

60、 e should be as small as possible. Differing wheel loads also lead to an increase in △Te so the difference should also be as small as possible.</p><p>　　When torque is transmitted by an articulated CV-Joint,

61、 on the drive side (subscript 1) and the driven side (subscript 2),differing secondary moments are produced that must have a reaction in a vertical plane relative to the plane of articulation. The magnitude and direction

62、 of the secondary moments (M) are calculated as follows (see Figure 8):</p><p>　　Drive side M1 =</p><p>　　Driven side M2 =</p><p>　　With T2 =</p><p><b>　

63、　=</b></p><p>　　Where Vertical Articulation Angle</p><p>　　Resulting Articulation Angle</p><p>　　Dynamic Wheel Radius</p><p>　　Average Torque Loss</p>

64、<p>　　The component acts around the king-pin axis (see figure 7) as a steering torque per wheel and as a steering torque difference between the wheels as follows:</p><p>　　where Steering Torque

65、Difference</p><p>　　WWheel side subscript</p><p>　　It is therefore apparent that not only differing driving torque but also differing articulations caused by various driveshaft lengths are also

66、a factor. Referring to the moment-polygon in Figure 7, the rotational direction of M2 or respectively change, depending on the position of the wheel-center to the gearbox output.</p><p>　　For the normal pos

67、ition of the halfshaft shown in Figure 7(wheel-center below the gearbox output joint) the secondary moments work in the same rotational direction as the driving forces. For a modified suspension layout (wheel-center abov

68、e gearbox output joint, i.e. negative) the secondary moments counteract the moments caused by the driving forces. Thus for good compatibility of the front axle with a limited-slip differential, the design requires: 1) ve

69、rtical bending angles which are centered a</p><p>　　The influence of the secondary moments on the steering is not only limited to the direct reactions described above. Indirect reactions from the connection

70、shaft between the wheel-side and the gearbox-side joint can also arise, as shown below:</p><p>　　Figure 9: Indirect Reactions Generated by Halfshaft Articulation in the Vertical Plane</p><p>　　F

71、or transmission of torque without loss and both of the secondary moments acting on the connection shaft compensate each other. In reality (with torque loss), however, a secondary moment difference appears:</p>&l

72、t;p><b>　　△</b></p><p>　　With </p><p>　　The secondary moment difference is:</p><p>　　For reasons of simplification it apply that and to give<

73、;/p><p><b>　　△</b></p><p>　　△ requires opposing reaction forces on both joints where . Due to the joint disturbance lever arm f, a further steering torque also acts around the king-pin

74、axis:</p><p>　　Where Steering Torque per Wheel</p><p>　　Steering Torque Difference</p><p>　　Joint Disturbance Lever</p><p>　　Connection shaft (halfshaft) Length</p&

75、gt;<p>　　For small values of f, which should be ideally zero, is of minor influence.</p><p>　　The viscous coupling in a front-wheel drive vehicle without ABS (anti-lock braking system) has only a ver

76、y small influence on the braking behavior on split-μ surfaces. Hence the front-wheels are connected partially via the front-wheel on the low-μ side is slightly higher than in an vehicle with an open differential. On the

77、other side ,the brake pressure to lock the front-wheel on the high-μ side is slightly lower. These differences can be measured in an instrumented test vehicle but are hardly n</p><p>　　Most ABS offered today

78、 have individual control of each front wheel. Electronic ABS in front-wheel drive vehicles must allow for the considerable differences in effective wheel inertia between braking with the clutch engaged and disengaged.<

79、;/p><p>　　Partial coupling of the front wheels through the viscous unit does not therefore compromise the action of the ABS - a fact that has been confirmed by numerous tests and by several independent car manu

80、facturers. The one theoretical exception to this occurs on a split-μ—surface if a yaw moment build-up delay or Yaw Moment Reduction(YMR) is included in the ABS control unit. Figure 18 shows typical brake pressure sequenc

81、es, with and without YMR.</p><p>　　figure 18: brake pressure build-up characteristics for the front brakes of a vehicle braking on split-μ with ABS. </p><p>　　In vehicles with low yaw inertia a

82、nd a short wheelbase, the yaw moment build-up can be delayed to allow an average driver enough reaction time by slowing the brake pressure build-up over the ABS for the high-μ wheel. The wheel on the surface with the hig

83、her friction coefficient is therefore, particularly at the beginning of braking, under-braked and runs with less slip. The low-μ wheel, in contrast, can at the same time have a very high slip, which results in a speed di