【正文】 e to utilize the higher adhesion potential of the wheel on the highμ surface. This is schematically shown in Figure 4. When for example, the maximum transmittable torque for one wheel is exceeded on a splitμ surface or during cornering with high lateral acceleration, a speed difference between the two driving wheels occurs. The resulting selflocking 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 lowμ side, To keep the vehicle in a straight line the driver has to pensate this with opposite steering input. Though the fluidfriction principle of the viscous coupling and the resulting soft transition from open to locking action, this is easily possible, The appropriate results obtained from vehicle tests are shown in Figure 5. Reported are the average steeringwheel torque Ts and the average corrective opposite steering input required to maintain a straight course during acceleration on a splitμ track 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 parison to each other. However, they are small in absolute terms. Subjectively, the steering influence is nearly 3 unnoticeable. The torque steer is also influenced by several kinematic parameters which will be explained in the next section of this paper. 4 FACTORS AFFECTING STEERING TORQUE As shown in Figure 6 the tractive forces lead to an increase in the toein response per wheel. For differing tractive forces, Which appear when accelerating on splitμ with limitedslip differentials, the toein response changes per wheel are also different. Unfortunately, this effect leads to an undesirable turnin response to the lowμ side, . the same yaw direction as caused by the difference in the tractive forces. Reduced toein elasticity is thus an essential requirement for the successful frontaxle application of a viscous limitedslip differential as well as any other type of limitedslip differential. Generally the following equations apply to the driving forces on a wheel ?VT FF ? With ?TF Tractive Force ?VF Vertical Wheel Load ?? Utilized Adhesion Coefficient These driving forces result in steering torque at each wheel via the wheel disturbance level arm “e” and a steering torque difference between the wheels given by the equation: △ eT = ? ?loHhiH FFe ?? ??? ?c o s Where △ ?eT Steering Torque Difference e=Wheel Disturbance Level Arm ?? King Pin Angle hi=highμ side subscript lo=lowμ side subscript In the case of frontwheel drive vehicles with open differentials, △ Ts is almost unnoticeable, since the torque bias ( loHhiT FF ?? / ) is no more than . For applications with limitedslip differentials, however, the influence is significant. Thus the wheel disturbance lever arm 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. When torque is transmitted by an articulated CVJoint, 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 of the secondary moments (M) are calculated as follows (see Figure 8): 4 Drive side M1 = vv TT ?? ? tan/)2/ta n (2 ?? Driven side M2 = vv TT ?? ? tan/)2/ta n (2 ?? With T2 = dynT rF? ?T = ? ?systemJoTf in t,2 ? Where v? ?? Vertical Articulation Angle ? ??Resulting Articulation Angle dynr ??Dynamic Wheel Radius ?T ??Average Torque Loss The ponent ?cos2?M acts around the kingpin axis (see figure 7) as a steering torque per wheel and as a steering torque difference between the wheels as follows: ])t a n/2/t a n()s i n/2/t a n[(c o s 22 liwhiw TTTTT ?? ?????? ??????? ????? where ????T Steering Torque Difference W?? Wheel side subscript It is therefore apparent that not only differing driving torque but also differing articulations caused by various driveshaft lengths are also a factor. Referring to the momentpolygon in Figure 7, the rotational direction of M2 or ?T respectively change, depending on the position of the wheelcenter to the gearbox output. For the normal position of the halfshaft shown in Figure 7(wheelcenter below the gearbox output joint) the secondary moments work in the same rotational direction as the driving forces. For a modified suspension layout (wheelcenter above gearbox output joint, . v? negative) the secondary moments counteract the moments caused by the driving forces. Thus for good patibility of the front axle with a limitedslip differential, the design requires: 1) vertical bending angles which are centered around 0?v? or negative ( 0?v? ) with same values of v? on both left and right sides。在歐洲和日本前輪驅(qū)動轎車產(chǎn)量的施用已經(jīng)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。 黏性連接器是根據(jù)液體摩擦的原理和依靠速度差來運轉(zhuǎn)的。其次，差速器架和轉(zhuǎn)送軸套只需要很小的修改。 3 牽引力的影響 作為一個扭轉(zhuǎn)力平衡裝置，一個開的差速器提供相等的力到兩個驅(qū)動輪上。然而，在絕對條件下它們是小的。 c o s ( )ioe H h H lT e F F? ??? ? ? ? ? 這里 eT? — 扭轉(zhuǎn)力矩差值 e— 車輪干擾常數(shù) ? — 主銷傾角 ih — 高滑動系數(shù)一側(cè)下標 ol — 低滑動系數(shù)一側(cè)下標 在帶有開式差速器前輪驅(qū)動汽車的情況下， ST? 是很不明顯的，因為扭轉(zhuǎn)力基數(shù)( / )H hi H loFF??是不大于 的。由于改進的懸掛裝置設(shè)計（車輪中心高于變速箱輸出點，也就是說， v? 為負值）第二個力矩抵消了由驅(qū)動力引起的力矩。 如圖表 10：前輪驅(qū)動力的汽車穩(wěn)定狀態(tài)下轉(zhuǎn)向時的牽引力。 安裝有 開式差速器的高動力前輪驅(qū)動汽車當以低檔加速離開緊急轉(zhuǎn)角時通常旋轉(zhuǎn)它們的內(nèi)側(cè)車輪。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)動輪上增加了縱 16 向力。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(qū)動輪更容