【正文】 因此黏性聯(lián)結(jié)器為一個(gè)正常的駕駛員改善節(jié)氣門關(guān)閉的行為方式當(dāng)保持可控制，可預(yù)言的并且安全駕駛時(shí)。圖表 16 在轉(zhuǎn)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(qū)動(dòng)汽車的節(jié)氣門關(guān)閉特性如圖表 17 在轉(zhuǎn)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(jié)器前輪驅(qū)動(dòng)汽車的節(jié)氣門關(guān)閉特性安裝有開式差速器的汽車側(cè)偏速度（側(cè)偏率） ，和相對(duì)的側(cè)偏角（除汽車保持繼續(xù)在穩(wěn)定狀態(tài)下轉(zhuǎn)彎的側(cè)偏角之外）在節(jié)氣門關(guān)閉后（時(shí)間為零如圖表 14 和 15）顯示一個(gè)非常明顯的增加。前輪上的驅(qū)動(dòng)力不再滾動(dòng)或者以后制動(dòng)力，黏性裝置汽車這個(gè)解釋在圖表 15 中。然而，實(shí)質(zhì)上的原因，是動(dòng)力的重心從后軸轉(zhuǎn)移到前軸，這會(huì)導(dǎo)致前軸降低滑動(dòng)角?？紤]到，所有的情況，裝配有一個(gè)黏性連接器的汽車在加速過(guò)程中具有穩(wěn)定的加速行動(dòng)方式在光滑路面上只有小的缺點(diǎn)。在非常低的摩擦力表面，例如雪或者冰，當(dāng)裝有限制滑動(dòng)差速器的汽車在曲線路面上加速時(shí)更強(qiáng)的操縱性被期望因?yàn)橥ㄟ^(guò)黏性連接器連接的驅(qū)動(dòng)輪更容易旋轉(zhuǎn)（動(dòng)力轉(zhuǎn)向裝置） 。安裝有限制滑動(dòng)前差速器的汽車在轉(zhuǎn)彎過(guò)程中加速時(shí)具有一個(gè)更穩(wěn)定的最初反應(yīng)比裝有開式差速器的汽車，降低它的操縱狀態(tài)。前輪傳遞側(cè)偏力潛能降低的原理是由于重心移到后軸車輪并且在驅(qū)動(dòng)輪上增加了縱向力。圖表 13 和 14 顯示了裝有開式差速器和裝有黏性限制滑動(dòng)差速器在穩(wěn)定狀態(tài)下轉(zhuǎn)彎過(guò)程中加速試驗(yàn)的結(jié)果。11 / 13安裝有開式差速器的高動(dòng)力前輪驅(qū)動(dòng)汽車當(dāng)以低檔加速離開緊急轉(zhuǎn)角時(shí)通常旋轉(zhuǎn)它們的內(nèi)側(cè)車輪。如圖表 11：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(zhuǎn)彎時(shí)的對(duì)比如圖表 10 所示在轉(zhuǎn)彎時(shí)不對(duì)稱的牽引力干擾也會(huì)改進(jìn)汽車的直線行駛。如圖表 10：前輪驅(qū)動(dòng)力的汽車穩(wěn)定狀態(tài)下轉(zhuǎn)向時(shí)的牽引力。然而，事vwd??10 / 13實(shí)上（有扭轉(zhuǎn)力損失） ，第二個(gè)力矩出現(xiàn)不同： 21DWWM??? 2T??第二個(gè)力矩不同點(diǎn)是： 2 2()tan/2sinta//tanDWVDWvwWvwTT?? ???????為了簡(jiǎn)化應(yīng)用給出 和f?VDW???(ta/1si/ta)DWvvvMT??A需要在兩個(gè)連接處都有抵抗反應(yīng)的力這里?。由于改進(jìn)的懸掛裝置設(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）v?第二個(gè)力矩抵消了由驅(qū)動(dòng)力引起的力矩。eTA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)垂直平面相對(duì)于連接平面的不同的第二個(gè)力矩產(chǎn)生了。 cos()ioeHhlTF?????這里 —扭轉(zhuǎn)力矩差值 e—車輪干擾常數(shù) — 主銷傾角?—高滑動(dòng)系數(shù)一側(cè)下標(biāo)ih—低滑動(dòng)系數(shù)一側(cè)下標(biāo)ol 在帶有開式差速器前輪驅(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)ST?是不大于 的。因?yàn)閹в邢拗苹瑒?dòng)差速器的車輪在滑動(dòng)系數(shù) 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。然而，在絕對(duì)條件下它們是小的。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)，8 / 13適的扭轉(zhuǎn)力到車輪上它具有更好的牽引力潛能。3 牽引力的影響作為一個(gè)扭轉(zhuǎn)力平衡裝置，一個(gè)開的差速器提供相等的力到兩個(gè)驅(qū)動(dòng)輪上。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。其次，差速器架和轉(zhuǎn)送軸套只需要很小的修改。外面的方式如圖 2 所示。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。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。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。 (figure 19,middle). Since most vehicle and ABS manufacturers consider 90176。1 / 13The Effect of a Viscous Coupling Used as a FrontWheel Drive LimitedSlip Differential on Vehicle Traction and Handling1 ABCTRACTThe viscous coupling is known mainly as a driveline ponent in four wheel drive vehicles. Developments in recent years, however, point toward the probability that this device will bee a major player in mainstream frontwheel drive application. Production application in European and Japanese frontwheel 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 frontwheel drive vehicle on traction and handing. Testing demonstrates substantial traction improvements while only slightly influencing steering torque. Factors affecting this steering torque in frontwheel drive vehicles during straight line driving are described. Key vehicle design parameters are identified which greatly influence the patibility of limitedslip differentials in frontwheel drive vehicles.Cornering tests show the influence of the viscous coupling on the self steering behavior of a frontwheel drive vehicle. Further testing demonstrates that a vehicle with a viscous limitedslip differential exhibits an improved stability under acceleration and throttleoff maneuvers during cornering.2 THE VISCOUS COUPLINGThe viscous coupling is a well known ponent 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 frontwheel drive vehicle the viscous coupling can be installed inside the differential or externally on an intermediate shaft. The external solution is shown in Figure 2.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 frontaxle differentials. Further, only minimal modification to the differential carrier and transmission case is required. Inhouse 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 plete unit. Finally, the intermediate shaft makes it possible to provide for sideshafts of equal length with transversely installed engines which is important to reduce torque steer (shown later in section 4).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. An example of this development is shown in Figure 3.3 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 windup. These characteristics, however, can be disadvantageous when adhesion variations between the left and right sides of the road surface (splitμ) limits the torque transmitted for both wheels to that which can be supported by the lowμ wheel.With a viscous limitedslip differential, it is possible to utilize the higher adhesion potential of the wheel on the highμsurface. This is schematically shown in Figure 4.When for example, the maximum transmittable torque for one wheel is exceeded on a splitμs