2358 車床濾油器加工工藝及關鍵工序工裝設計

2358 車床濾油器加工工藝及關鍵工序工裝設計,車床,濾油器,加工,工藝,關鍵,癥結,樞紐,工序,工裝,設計 南京理工大學泰州科技學院畢業(yè)設計(論文)外文資料翻譯系　　部： 機械工程 專 業(yè)： 機械工程及自動化 姓 名： 吳煒 學 號： 05010140 外文出處： https://shop.sae.org 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導教師評語：簽名： 年 月 日注：請將該封面與附件裝訂成冊。(用外文寫)附件 1：外文資料翻譯譯文黏性連接器用作前輪驅動時限制滑移對汽車牽引和操縱的影響1 基本概念黏性連接器主要地被認為是在四輪驅動的汽車上驅動路線的部件。然而在近些年的發(fā)展中，在主流的前輪驅動設備中這種裝置將成為主要角色，這個觀點是有可能的。在歐洲和日本前輪驅動轎車產量的施用已經證明黏性連接器不僅對于光滑路面的汽車牽引，而且在正常行駛條件下對于操縱性和穩(wěn)定性都有所改善。這篇文章展現(xiàn)了一系列地面測試試驗，顯示黏性連接器對前輪驅動汽車牽引和操縱的影響。試驗證明僅有輕微轉向扭轉的時候，牽引力才會改善。前輪驅動的汽車在直線行駛時，影響發(fā)動機轉矩的因素被確定出來。確定關鍵汽車設計參數(shù)，對前輪驅動的汽車的限制滑移差速器適合性有極大地影響。轉彎試驗展現(xiàn)出黏性連接器在前輪驅動的汽車上獨立轉彎時的影響。進一步的試驗證明安裝黏性限制滑移差速器的汽車在加速和轉彎時節(jié)氣門頻繁關閉的情況下顯示出一個理想的穩(wěn)定性。2 黏性連接器黏性連接器被廣泛認為是驅動列車的組成部件。在這篇文章中僅僅給出它的基本功能和原理的簡明概要。黏性連接器是根據液體摩擦的原理和依靠速度差來運轉的。正如圖 1 所示黏性連接器的滑動控制特性和驅動觀察系統(tǒng)的對比。這表明傳送到前輪的驅動扭轉力是由一個優(yōu)化的扭轉力分配檢測器自動控制的。在前輪驅動的汽車上黏性連接器可以安裝在差速器的內側或者一根中間軸的外面。內部的這種設計方式有很大的優(yōu)點。首先，在中間軸區(qū)域可以得到足夠的空間來提供符合要求的黏性特性。這和當今前輪軸差速器只留下有限的空間相對比。其次，差速器架和轉送軸套只需要很小的修改。而且差速器殼體的生產也僅僅只有一點影響。引用作為一個選擇性的事很容易做到尤其當軸和黏性單元作為一個整體單元被共給時。最后，中間軸使為等長的的側偏軸提供橫向安裝發(fā)動機是可能的，橫向地安裝發(fā)動機對于減小扭轉力的操縱是很重要的（后面第四部分說明了） 。這種特殊的設計也為有實際意義的重量和黏性單元費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。通過使用僅僅兩個標準化的直徑、標準化的盤，塑料輪轂和擠壓成型的材料造成的儲存室它能很容易地被截成不同的長度，使用一個寬的黏性范圍是可能的。在圖 3 中顯示出這種發(fā)展的一個例子。3 牽引力的影響作為一個扭轉力平衡裝置，一個開的差速器提供相等的力到兩個驅動輪上。它也允許每個車輪在扭轉沒結束轉彎時以不同的速度轉動。然而，這種特性當?shù)缆繁砻婊瑒酉禂?shù)為 限制扭轉力傳遞到兩輪的左、右附著變動時是不利的，它能?被低滑動系數(shù) 的輪子支持。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潛在性的附?著。例如，當一個車輪傳遞的最大扭轉力超出表面滑動系數(shù) 允許值或者以一個?高的側面加速度轉彎時，兩個車輪的速度是不同的.在黏性連接器中產生的自鎖扭轉力抵抗速度差的增加并且傳遞合適的扭轉力到車輪上它具有更好的牽引力潛能?？梢钥闯鰻恳Φ牟煌瑢е缕囁查g向低滑動系數(shù)值( )一側跑偏，為了保?持汽車直線行駛駕駛員必須施加一個相反的扭轉力來補償。通過黏性連接器的液體摩擦原理和從打開到鎖死柔和的傳遞結果,這是很可能的。報告稱平均操縱輪扭轉力 和為保持帶有一個開式的并且黏性的差速器在加ST速期間在滑動系數(shù) 的路面上直線行駛應輸入的平均正確的相對的轉向操縱。相?互對照開式差速器和那些黏性連接器是相對大的。然而，在絕對條件下它們是小的。主觀地說，轉向裝置的影響是不明顯的。扭轉力操縱也受幾個運動參數(shù)影響這些參數(shù)將在這篇文章下個部分解釋。4 影響轉向裝置扭轉力的因素牽引力引起一個從頭到尾的增加來反應每個車輪。因為帶有限制滑動差速器的車輪在滑動系數(shù) 的路面上加速時會出現(xiàn)不同的牽引力，所以從頭到尾反應每?個車輪的變化也是不同的。不幸的是，這個作用將導致一個不期望的朝低滑動系數(shù)一側的反應，也就是說在不同的牽引力下產生相同的跑偏方向。降低從頭到尾的彈力是黏性限制滑動差速器像其它任何形式差速器一樣在前軸的成功應用所必須具備的。普遍地用下面的公式計算一個車輪的驅動力 TVF??—牽引力—車輪垂直載荷V—利用的附著系數(shù)?這些驅動力導致在車輪之間每個車輪的轉向裝置扭轉力經過車輪干擾常數(shù) e干擾后與每個車輪的轉向裝置扭轉力是不同的，給出下面的等式。 cos()ioeHhlTF?????這里 —扭轉力矩差值e—車輪干擾常數(shù)— 主銷傾角?—高滑動系數(shù)一側下標ih—低滑動系數(shù)一側下標ol在帶有開式差速器前輪驅動汽車的情況下， 是很不明顯的，因為扭轉力基ST?數(shù) 是不大于 1.35 的。(/)HhiloF?然而，因為應用了限制滑動差速器，這個影響是很有意義的。這樣車輪干擾常數(shù) e 就應該盡可能的小。不同的車輪載荷也會導致 的增加所以差別也要盡eTA可能的小。當扭轉力通過鉸接“CV 連接”傳遞時，在主動一側（下標 1）和從動一側（下標 2） ，必須反應垂直平面相對于連接平面的不同的第二個力矩產生了。第二個力矩（M）大小和方向用于下面的式子計算：主動一側 12tan(/)/tanvvTT?????A從動一側 ?2TdynFr(,f???連 接 系 統(tǒng) ）這里 —縱向連接角v—產生的連接角 —產生變化的輪子半徑dynr—平均扭轉力矩損失T?當每個裝置的轉向扭轉力以及輪子之間的轉向裝置扭轉力不同時，將圍繞著主銷軸線變動，如下所示：2cosM?AT????2 2(tan/sin)(tan/tan)vvwhivvwliTT? ???? ?? ??? ?這里 —轉向裝置扭轉力矩差W—輪子一側的下標因此很明顯不僅不同的驅動扭轉力而且黏性驅動軸長度的不同也是一個因素。說道圖 7 中的力矩多邊形， 的旋轉方向或者 各自地變化，都取決于輪子中心2MT?到變速箱輸出的位置。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）第二個力矩產生和驅動力一樣的旋轉方向。由于改進的懸掛裝置設計（車輪中心高于變速箱輸出點，也就是說， 為負值）第二個力矩抵消了由驅動力引起的力矩。這樣v?為了得到帶一個限制滑動差速器前軸好的適應性，設計要求：1）縱向彎曲角近似或者負值（ ）且左側和右側的 值相等；2）等長度的側軸。0v??0v??v?第二力矩在轉向裝置的影響不僅僅是上面描述的限制直接反應。從連接軸到車輪側面和變速箱側面之間的連接點間接反應也會產生，如下所示：由縱向平面的半軸連接產生的間接反應因為扭轉力傳遞沒有損失并且 兩個在連接軸上的第二個力矩都相互vwd??補償。然而，事實上（有扭轉力損失） ，第二個力矩出現(xiàn)不同：21DWWM???2T??第二個力矩不同點是： 2 2()tan/2sinta//tanDWVDWvwWvwTT?? ???????為了簡化應用給出 和f?VD???(ta/1si/ta)DWvvvMT???A需要在兩個連接處都有抵抗反應的力這里。由連接處引起的干擾常數(shù) f，一個附加的轉向裝置扭轉力矩也圍/DWFL?繞著主銷軸線變動：cos/fDWTMf??A這里 —每個車輪的轉向裝置扭轉力矩f—轉向裝置扭轉力矩差ff—連接處干擾系數(shù)L—連接軸（半軸）的長度由于 f 值小，理想值是 0， 的影響較小。fT?5 轉彎時的效應扭轉時由于驅動輪的速度不相等，黏性連接器也提供一個自瑣的扭轉力矩。在平穩(wěn)轉向過程中，速度較慢的內側車輪被外側車輪黏性連接器施加的一個附加的驅動力。前輪驅動力的汽車穩(wěn)定狀態(tài)下轉向時的牽引力。不同的牽引力 和 導致一個側偏力矩 MCOG，它必須被一個較大的側偏flDrfl力補償，因此在前軸有一個大的滑動角 af。因此前驅動輪的汽車自動轉向裝置上黏性連接器的影響趨向一個在轉向裝置狀態(tài)下的特性。這個運動方式整體上和所有轉向操縱下在穩(wěn)定狀態(tài)下轉彎移動時的現(xiàn)代汽車操縱方式的偏重心相一致.合適的試驗結果如圖表 11 所示。安裝有開式差速器的汽車餓安裝有黏性連接器的汽車在穩(wěn)定狀態(tài)下轉彎時的對比所示在轉彎時不對稱的牽引力干擾也會改進汽車的直線行駛。每一次偏離正常的直線方向都會引起車輪以輕微的不同半徑滾動。驅動力和產生的側偏力矩差會使汽車重新回到直線行駛。雖然這些方向的偏離引起僅僅很小的車輪滾動半徑差，但是旋轉的偏差尤其在高速時對于一個黏性連接器前差速器是足夠將汽車帶到直線上行駛的。安裝有開式差速器的高動力前輪驅動汽車當以低檔加速離開緊急轉角時通常旋轉它們的內側車輪。安裝有限制滑動黏性差速器，這個旋轉是有限的并且有不同車輪的速度差產生的扭轉力為外側的驅動輪提供附加的牽引力效果。裝有黏性限制滑動差速器的前輪驅動汽車在轉道上加速時的牽引力特別地當行駛或加速離開一個 T 形交叉路口加速能力就這樣被改善（也就是說在 T 形路口橫切向右或向左從停止位置加速） 。顯示了裝有開式差速器和裝有黏性限制滑動差速器在穩(wěn)定狀態(tài)下轉彎過程中加速試驗的結果。裝有一個開式差速器的前輪驅動汽車在半徑為 40m 的濕瀝青彎曲路面上加速特性（實驗過程中安裝有轉向裝置輪角測試儀）裝有一個黏性連接器的前輪驅動汽車在半徑為 40m 的濕瀝青彎曲路面上加速特性（實驗過程中安裝有轉向裝置輪角測試儀）安裝有一個開式差速器的汽車平均加速度為 同時裝有黏性連接CSDM2.0/ms器的汽車平均加速度達到 （被發(fā)動機功率限制） 。在這些試驗中，由內側2.3/ms的從動輪引起的最大速度差，被從帶有開式差速器的 240rpm 減少到帶有黏性連接器的 100rpm。在彎道上加速行駛時，前輪驅動的汽車通常處在操縱狀態(tài)下要多于其勻速行駛的狀態(tài)。前輪傳遞側偏力潛能降低的原理是由于重心移到后軸車輪并且在驅動輪上增加了縱向力。在一個開式環(huán)形控制循環(huán)測試中這個能夠看出在開始加速以后（時間為 0 在圖表 13 和 14 中）偏跑速度（跑偏率）的降低。從圖表 13 和 14中還可以看出開始加速時裝有開式差速器汽車的跑偏率比裝有黏性連接器汽車的下降的更快。然而，在開始加速大約 2 秒后，黏性連接的汽車的跑偏率下降斜率增加高于裝有開式差速器 的汽車。安裝有限制滑動前差速器的汽車在轉彎過程中加速時具有一個更穩(wěn)定的最初反應比裝有開式差速器的汽車，降低它的操縱狀態(tài)。這是因為內側驅動輪的高滑動通過黏性連接器產生一個增加的驅動力到外側車輪。前輪牽引力的不平衡導致在行駛方向上的偏跑力矩 ，反對操縱狀態(tài)。CSDM當驅動輪的附著限制是超出的,安裝黏性連接器的汽車處于操縱狀態(tài)比安裝有開式差速器的汽車更明顯(這里,開始加速后 2 秒)。在非常低的摩擦力表面，例如雪或者冰，當裝有限制滑動差速器的汽車在曲線路面上加速時更強的操縱性被期望因為通過黏性連接器連接的驅動輪更容易旋轉（動力轉向裝置） 。然而，這個特性能很容易地被駕駛員或者自動節(jié)氣門調節(jié)牽引系統(tǒng)控制。在這些情況下比后輪驅動的汽車更容易控制。在轉彎過程中當加速時它能夠防止動力過分操縱。考慮到，所有的情況，裝配有一個黏性連接器的汽車在加速過程中具有穩(wěn)定的加速行動方式在光滑路面上只有小的缺點。通過突然釋放加速器，在轉彎過程中節(jié)氣門關閉的反應，通常導致前輪驅動的汽車改換方向（節(jié)氣門關閉超出了操縱） 。高動力的模型能得到高側偏加速度顯示出最大規(guī)模的反應。這個節(jié)氣門關閉反應有幾個原因例如運動學上的影響，或者，當汽車降低速度試著以一個較小的轉變半徑通過時。然而，實質上的原因，是動力的重心從后軸轉移到前軸，這會導致前軸降低滑動角。后軸增加滑動角。因為，后軸車輪不傳遞驅動力矩，在這種情況下在后軸上的影響比前軸上的影響更大。在節(jié)氣門關閉之前。 。安裝有黏性限制滑動差速器前輪驅動的汽車當轉變時關閉節(jié)氣門后移動立刻產生的制動力隨著內側的車輪繼續(xù)比外側車輪更慢的轉動，黏性聯(lián)結器給外側車輪提供更大的制動力 。由于前輪力的不同圍繞著汽車重量的中心會產生一個抵消正常?fB轉向反應的側偏力矩 MCOG.。將安裝有開式差速器的汽車和裝有黏性聯(lián)結器的在關閉節(jié)氣門的移動過程中轉向方式進行比較時，如圖表 16 和 17 所示，安裝有黏性差速器的兩個驅動輪子之間速度差是降低的。在轉彎半徑為 40 米（不封閉的環(huán)形）的濕瀝青路面上安裝有開式差速器前輪驅動汽車的節(jié)氣門關閉特性在轉彎半徑為 40 米（不封閉的環(huán)形）的濕瀝青路面上安裝有黏性聯(lián)結器前輪驅動汽車的節(jié)氣門關閉特性安裝有開式差速器的汽車側偏速度（側偏率） ，和相對的側偏角（除汽車保持繼續(xù)在穩(wěn)定狀態(tài)下轉彎的側偏角之外）在節(jié)氣門關閉后（時間為零如圖表 14 和15）顯示一個非常明顯的增加。在安裝有一個黏性的限制滑動差速器的汽車上節(jié)氣門關閉后側偏率的突然增加和相對側偏角的增加都有很大的降低。例如在一個彎道上隨著半徑的增加，一上正常的駕駛一個超大號的前輪驅動汽車的人通常僅僅的慣常的空檔的操縱裝置下的汽車操縱方式，然后駕駛員忽然驚奇并且在節(jié)氣門突然的釋放后會有有力的操縱反應。如果駕駛員對情況的反應不正確汽車將進一步惡化汽車離開車道到曲線的內側的事故是這個事件的驗證。因此黏性聯(lián)結器為一個正常的駕駛員改善節(jié)氣門關閉的行為方式當保持可控制，可預言的并且安全駕駛時。7 總結總之，黏性聯(lián)結器在前軸差速器的試用能被證實。它也明確地影響整個汽車的控制和穩(wěn)定，只是稍微地，但是可以接受的在扭轉力操縱上的影響。為了減小不想要的扭轉力操縱的影響一個基本的設計準則被給出：1 由于縱向載荷改變產生的警覺反應必須盡可能的小2 主銷軸線和車輪中心之間的距離必須盡可能的小3 垂直彎曲角變化范圍應該接近零（或者為負值）4 兩側的垂直彎曲角應該一樣5 側軸應該等長扭轉力操縱上最小影響是聯(lián)結處干擾常數(shù)的理想值為零。帶有和不帶有 ABS制動，僅對黏性聯(lián)結器僅有輕微的影響。在前輪驅動的汽車上，黏性限制滑動差速器顯著提高了牽引力。有獨立轉向裝置的前輪驅動汽車，在轉向時會輕微影響?zhàn)ば韵拗苹瑒硬钏倨?。前軸安裝有黏性聯(lián)結器的汽車，在轉彎過程中關閉氣門和改進加速的措施，使汽車更穩(wěn)定而且更安全。附件 2：外文原文The Effect of a Viscous Coupling Used as a Front-Wheel Drive Limited-Slip Differential on Vehicle Traction and Handling 1 ABCTRACTThe viscous coupling is known mainly as a driveline component in four wheel drive 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 front-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 conditions.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 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 influence the compatibility of limited-slip differentials in front-wheel drive vehicles.Cornering tests show the influence of the viscous coupling on the self steering behavior of a front-wheel drive vehicle. Further testing demonstrates that a vehicle with a viscous limited-slip differential exhibits an improved stability under acceleration and throttle-off maneuvers during cornering.2 THE VISCOUS COUPLINGThe 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.The viscous coupling operates according 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.This means that the drive torque which is transmitted to the front wheels is automatically controlled in the sense of an optimized torque distribution.In a front-wheel drive vehicle the viscous coupling can be installed inside the differential or externally on an intermediate shaft.This layout has some significant advantages over the internal solution. 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. 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 especially when the shaft and the viscous unit is supplied as a complete unit. Finally, the intermediate shaft makes it possible to provide for sideshafts of equal length with transversely installed engines which are important to reduce torque steer.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 standardized 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..3 TRACTION EFFECTSAs a torque balancing device, an open differential provides equal tractive effort to both driving wheels. It allows 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 surface (split-μ) limits the torque transmitted for both wheels to that which can be supported by the low-μ wheel.With a viscous limited-slip differential, it is possible to utilize the higher adhesion potential of the wheel on the high-μsurface..When for example, the maximum transmittable torque for one wheel is exceeded on a split-μsurface or during cornering 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 appropriate torque to the wheel with the better traction potential.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 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 open to locking action, this is easily possible.Reported are the average steering-wheel torque Ts and the average corrective 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 with 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 influenced by several kinematic parameters which will be explained in the next section of this paper.5．EFFECT ON CORNERINGViscous couplings also provide a self-locking torque when cornering, due to speed differences between the driving wheels. During steady state cornering, as shown in figure 10, the slower inside wheel tends to be additionally driven through the viscous coupling by the outside wheel.Tractive forces for a front-wheel drive vehicle during steady state cornering The difference between the Tractive forces Dfr and Dfl results in a yaw moment MCOG, which has to be compensated by a higher lateral force, and hence a larger slip angle af at the front axle. Thus the influence of a viscous coupling in a front-wheel drive vehicle on self-steering tends towards an understeering characteristic. This behavior is totally consistent with the handling bias of modern vehicles which all under steer during steady state cornering maneuvers. Appropriate test results are shown in figure 11.Figure 11: comparison between vehicles fitted with an open differential and viscous coupling during steady state cornering.The asymmetric distribution of the tractive forces during cornering as shown in figure 10 improves also the straight-line running. Every deviation from the straight-line position causes the wheels to roll on slightly different radii. The difference between the driving forces and the resulting yaw moment tries to restore the vehicle to straight-line running again.Although these directional deviations result in only small differences in wheel travel radii, the rotational differences especially at high speeds are large enough for a viscous coupling front differential to bring improvements in straight-line running.High powered front-wheel drive vehicles fitted with open differentials often spin their inside wheels when accelerating out of tight corners in low gear. In vehicles fitted with limited-slip viscous differentials, this spinning is limited and the torque generated by the speed difference between the wheels provides additional tractive effort for the outside driving wheel.Tractate forces for a front-wheel drive vehicle with viscous limited-slip differential during acceleration in a bend The acceleration capacity is thus improved, particularly when turning or accelerating out of a T-junction maneuver (i.e. accelerating from a stopped position at a “T” intersection-right or left turn).the results of acceleration tests during steady state cornering with an open differential and with viscous limited-slip differential.Accelerations characteristic for a front-wheel drive vehicle with an open differential on wet asphalt at a radius of 40m (fixed steering wheel angle throughout test).Acceleration Characteristics for a Front-Wheel Drive Vehicle with Viscous Coupling on Wet Asphalt at a Radius of 40m (Fixed steering wheel angle throughout test)The vehicle with an open differential achieves an average acceleration of 2.0 2/smwhile thevehicle with the viscous coupling reaches an average of 2.3 (limited by 2/sengine-power). In these tests, the maximum speed difference, caused by spinning of the inside driven wheel was reduced from 240 rpm with open differential to 100 rpm with the viscous coupling.During acceleration in a bend, front-wheel drive vehicles in general tend to understeer more than when running at a steady speed. The reason for this is the reduction of the potential to transmit lateral forces at the front-tires due to weight transfer to the rear wheels and increased longitudinal forces at the driving wheels. In an open loop control-circle-test this can be seen in the drop of the yawing speed (yaw rate) after starting to accelerate (Time 0 in Figure 13 and 14). It can also be taken from Figure 13 and Figure 14 that the yaw rate of the vehicle with the open differential falls-off more rapidly than for the vehicle with the viscous coupling starting to accelerate. Approximately 2 seconds after starting to accelerate, however, the yaw rate fall-off gradient of the viscous-coupled vehicle increases more than at the vehicle with open differential.The vehicle with the limited slip front differential thus has a more stable initial reaction under accelerating during cornering than the vehicle with the open differential, reducing its understeer. This is due to the higher slip at the inside driving wheel causing an increase in driving force through the viscous coupling to the outside wheel. The imbalance in the front wheel tractive forces results in a yaw moment acting in CSDMdirection of the turn, countering the understeer.When the adhesion limits of the driving wheels are exceed, the vehicle with the viscous coupling understeers more noticeably than the vehicle with the open differential (here, 2 seconds after starting to accelerate). On very low friction surfaces, such as snow or ice, stronger understeer is to be expected when accelerating in a curve with a limited slip differential because the driving wheels-connected through the viscous coupling-can be made to spin more easily (power-under-steering). This characteristic can, however, be easily controlied by the driver or by an automatic throttle modulating traction control system. Under these conditions a much easier to control than a rear-wheel drive car. Which can exhibit power-oversteering when accelerating during cornering. All things, considered, the advantage through the stabilized acceleration behavior of a viscous coupling equipped vehicle during acceleration the small disadvantage on slippery surfaces.Throttle-off reactions during cornering, caused by releasing the accelerator suddenly, usually result in a front-wheel drive vehicle turning into the turn (throttle-off oversteering ). High-powered modeles which can reach high lateral accelerations show the heaviest reactions. This throttle-off reaction has several causes such as kinematic influence, or as the vehicle attempting to travel on a smaller cornering radius with reducing speed. The essential reason, however, is the dynamic weight transfer from the rear to the front axle, which results in reduced slip-angles on the front and increased slip-angles on the rear wheels. Because the rear wheels are not transmitting driving torque, the influence on the rear axle in this case is greater than that of the front axle. The driving forces on the front wheels before throttle-off (see Figure 10) become over running or braking forces afterwards.Baraking Forces for a Front-Wheel Drive Vehicle with Viscous Limited-Slip Differential Immediately after a Throttle-off Maneuver While CorneringAs the inner wheel continued to turn more slowly than the outer wheel, the viscous coupling provides the outer wheel with the larger braking force . The force difference fBbetween the front-wheels applied around the center of gravity of the vehicle causes a yaw moment that counteracts the normal turn-in reaction.GCM0When cornering behavior during a throttle-off maneuver is compared for vehicles with open differentials and viscous couplings, as shown in Figure 16 and 17, the speed difference between the two driving wheels is reduced with a viscous differential.Throttle-off Characteristics for a Front-Wheel Drive Vehicle with an open Differential on Wet Asphalt at a Radius of 40m (Open Loop)Throttle-off Characteristics for a Front-Wheel Drive Vehicle with Viscous Coupling on Wet Asphalt at a Radius of 40m (Open Loop)The yawing speed (yaw rate), and the relative yawing angle (in addition to the yaw angle which the vehicle would have maintained in case of continued steady state cornering) show a pronounced increase after throttle-off (Time=0 seconds in Figure 14 and 15) with the open differential. Both the sudden increase of the yaw rate after throttle-off and also the increase of the relative yaw angle are significantly reduced in the vehicle equipped with a viscous limited-slip differential.A normal driver os a front-wheel drive vehicle is usually only accustomed to neutral and understeering vehicle handing behavior, the driver can then be surprised by sudden and forceful oversteering reaction after an abrupt release of the throttle, for example in a bend with decreasing radius. This vehicle reaction is further worsened if the driver over-corrects for the situation. Accidents where cars leave the road to the inner side of the curve is proof of this occurrence. Hence the viscous coupling improves the throttle-off behavior while remaining controllable, predictable, and safer for an average driver.6 SUMMARYIn conclusion, it can be established that the application of a viscous coupling in a front-axle differential. It als