<acronym id="6i0ao"><small id="6i0ao"></small></acronym>
<acronym id="6i0ao"><center id="6i0ao"></center></acronym>
欢迎来到文库吧! | 帮助中心 坚持梦想,走向成功!
文库吧
首页 文库吧 > 资源分类 > DOC文档下载
 

外文翻译--黏性连接器用作前轮驱动限制滑移差速器对汽车牵引和操纵的影响-汽车设计.doc

  • 资源ID:7422       资源大小:77.00KB        全文页数:13页
  • 资源格式: DOC        下载权限:游客/注册会员/VIP会员    下载费用:10
换?#25442;?/a>
游客快捷下载 游客一键下载
会员登录下载

支付方式: 微信支付    支付宝   
验证码:   换?#25442;?/a>

      加入VIP,下载共享资源
 
友情提示
2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网?#36710;?#26700;面,既可以正常下载了。
3、本站不支持迅雷下载,请使用电脑?#28304;?#30340;IE浏览器,或者360浏览器、谷歌浏览器下载即可。
4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译--黏性连接器用作前轮驱动限制滑移差速器对汽车牵引和操纵的影响-汽车设计.doc

毕业设计论文外文资料翻译 系 部 机械工程系 专 业 机械工程及自动化 姓 名 学 号 外文出处The Effect of a Viscous Coupling Used as a Front-Wheel Drive Limited-Slip Differential on Vehicle Traction and Handling 附 件1.外文资料翻译译文;2.外文原 文。 用外文写 附件 1外文资料翻译译文 黏性连接器用作前轮驱动限制滑移差速器对汽车牵 引和操纵的影响 5 转弯时的效应 扭转时由于驱动轮的速度不相等,黏性连接器也提供一个自琐的扭转力矩。 如图表 10 所示,在平稳转向过程中,速度?#19979;?#30340;内侧车轮被外侧车轮黏性连接器 施加的一个附加的驱动力。 如图表 10前轮驱动力的汽车稳定状态下转向时的牵引力。 不同的牵引力 和 导致一个侧偏力矩 MCOG,它必须被一个较大的侧偏flDrfl 力补偿,因此在前轴有一个大的滑动角 af。因此前驱动轮的汽车自动转向装置上 黏性连接器的影响趋向一个在转向装置状态下的特性。这个运动方式整体上和所 有转向操纵下在稳定状态下转弯移动时的现代汽车操纵方式的偏重心相一致.合适 的试验结果如图表 11 所示。 如图表 11安装有开式差速器的汽车饿安装有黏性连接器的汽车在稳定状态 下转弯时的对比 如图表 10 所示在转弯时不对称的牵引力干扰也会改进汽车的?#27605;?#34892;驶。每一 次偏离正常的?#27605;?#26041;向都会引起车轮以轻微的不同半径滚动。驱动力和产生的侧 偏力矩差会使汽车重新回到?#27605;?#34892;驶(如图表 10) 。 虽然这些方向的偏离引起仅仅很小的车轮滚动半径差,但是旋转的偏差尤其 在高速时对于一个黏性连接器前差速器是足够将汽车带到?#27605;?#19978;行驶的。 安装有开式差速器的高动力前轮驱动汽车当以低?#23548;?#36895;离开紧急转角时通常 旋转它们的内侧车轮。安装有限制滑动黏性差速器,这个旋转是有限的并且有不 同车轮的速度差产生的扭转力为外侧的驱动轮提供附加的牵引力效果。这显示在 图表 12 中。 如图表 12装有黏性限制滑动差速器的前轮驱动汽车在转道上加速时的牵引 力 特别地当行?#25442;?#21152;速离开一个 T 形交叉路口加速能力就这样被改善(也就是 说在 T 形路口横切向?#19968;?#21521;左从停止位置加速) 。 图表 13 和 14 显示了装有开式差速器和装有黏性限制滑动差速器在稳定状态 下转弯过程中加速试验的结果。 如图表 13 所示装有一个开式差速器的前轮驱动汽车在半径为 40m 的湿沥青 弯曲路面上加速特性(实验过程中安装有转向装置轮角测试?#29301;?如图表 14 所示装有一个黏性连接器的前轮驱动汽车在半径为 40m 的湿沥青 弯曲路面上加速特性(实验过程中安装有转向装置轮角测试?#29301;?安装有一个开式差速器的汽车平均加速度为 同时装有黏性连接CSDM2.0/ms 器的汽车平均加速度达到 (?#29615;?#21160;机功率限制) 。在这些试验中,由内侧2.3/ms 的从动轮引起的最大速度差,被从带有开式差速器的 240rpm 减少到带有黏性连接 器的 100rpm。 在弯道上加速行驶?#20445;?#21069;轮驱动的汽车通常处在操纵状态下要多于其匀速行 驶的状态。前轮传递侧偏力潜能?#26723;?#30340;原理是由于重心移到后轴车轮并且在驱动 轮上增加了纵向力。在一个开式环形控制循环测试?#22995;?#20010;能够看出在开?#25216;?#36895;以 后(时间为 0 在图表 13 和 14 中)偏跑速度(跑偏率)的?#26723;汀?#20174;图表 13 和 14 中还可以看出开?#25216;?#36895;时装有开式差速器汽车的跑偏?#26102;?#35013;有黏性连接器汽车的 下降的更快。?#27426;?#22312;开?#25216;?#36895;大约 2 秒后,黏性连接的汽车的跑偏率下降斜率 增加高于装有开式差速器 的汽车。 安装有限制滑动前差速器的汽车在转弯过程中加速时具有一个更稳定的最初 反应比装有开式差速器的汽车,?#26723;?#23427;的操纵状态。这是因为内侧驱动轮的高滑 动通过黏性连接器产生一个增加的驱动力到外侧车轮,这在图表 12 中有解释。前 轮牵引力的不平衡导致在行?#29615;?#21521;上的偏跑力矩 ,反对操纵状态。CSDM 当驱动轮的附着限制是超出的,安装黏性连接器的汽车处于操纵状态比安装有 开式差速器的汽车更明显这里,开?#25216;?#36895;后 2 秒。在非常低的摩擦力表面,例如 雪或者冰,当装有限制滑动差速器的汽车在曲线路面上加速时更强的操纵性被期 望因为通过黏性连接器连接的驱动轮更容易旋转(动力转向装置) 。?#27426;?#36825;个特 性能很容易地被驾驶员或者自动节气门调节牵引系统控制。在这些情况下比后轮 驱动的汽车更容易控制。在转弯过程?#26800;?#21152;速时它能?#29615;乐?#21160;力过分操纵。考虑 到,所有的情况,装配有一个黏性连接器的汽车在加速过程中具有稳定的加速行 动方式在光滑路面上只有小的缺点。 通过突然释放加速器,在转弯过程中节气门关闭的反应,通常导致前轮驱动 的汽车改?#29615;?#21521;(节气门关闭超出了操纵) 。高动力的模型能得到高侧偏加速度显 示出最大规模的反应。这个节气门关闭反应有几个原因例如运动学上的影响,或 者,当汽车?#26723;?#36895;度试着以一个较小的转变半径通过时。?#27426;?#23454;质上的原因, 是动力的重心从后轴转移到前轴,这会导致前轴?#26723;?#28369;动角。后轴增加滑动角。 因为,后轴车轮不传递驱动力矩,在这种情况下在后轴上的影响比前轴上的影响 更大。在节气门关闭之前(如图表 10) 。前轮上的驱动力不再滚动或者以后制动力, 黏性装置汽车这个解释在图表 15 中。 如图表 15安装有黏性限制滑动差速器前轮驱动的汽车当转变时关闭节气门 后移动立刻产生的制动力 随着内侧的车轮继续比外侧车轮更慢的转动,黏性联结器给外侧车轮提供更 大的制动力 。由于前轮力的不同围绕着汽车重量的中心会产生一个抵消正常?fB 转向反应的侧偏力矩 MCOG.。 将安装有开式差速器的汽车和装有黏性联结器的在关闭节气门的移动过程中 转向方式进行比较?#20445;?#22914;图表 16 和 17 所示,安装有黏性差速器的两个驱动轮子 之间速度差是?#26723;?#30340;。 图表 16 在转弯半径为 40 米(?#29615;?#38381;的环形)的湿沥青路面上安装有开式差 速器前轮驱动汽车的节气门关闭特性 如图表 17 在转弯半径为 40 米(?#29615;?#38381;的环形)的湿沥青路面上安装有黏性 联结器前轮驱动汽车的节气门关闭特性 安装有开式差速器的汽车侧偏速度(侧偏率) ,和相对的侧偏?#29301;?#38500;汽车保持 继续在稳定状态下转弯的侧偏?#20405;?#22806;)在节气门关闭后(时间为零如图表 14 和 15)显示一个非常明显的增加。在安装有一个黏性的限制滑动差速器的汽车上节 气门关闭后侧偏率的突然增加和相对侧偏角的增加都有很大的?#26723;汀?例如在一个弯道上随着半径的增加,一上正常的驾驶一个超大号的前轮驱动 汽车的人通常仅仅的惯常的空档的操纵装置下的汽车操纵方式,然后驾驶员忽然 惊奇并且在节气门突然的释放后会有有力的操纵反应。如果驾驶员对情况的反应 不正确汽车将进一步恶化汽车离开车道到曲线的内侧的事?#36866;?#36825;个事件的验证。 因此黏性联结器为一个正常的驾驶员改善节气门关闭的行为方式当保持可控制, 可预言的并且安全驾驶时。 虽然这也许会被认为是一个?#22909;?#24433;响而且对于一辆安装有前黏性联结器的汽 车来?#26723;?#23433;装 YMR 计算程序就能很容易地被修正,但是汽车试验已经证明这个影 响是很小的,?#23548;?#19978;不需要专门的新的 ABS/YMR 计算程序的开发。一些典型的求 平均的测试结果被总结如图表 19。 如图表 19结果构成了带有 YMR 在滑动系数为 (V 050mph,三档,闭环)上? 的 ABS 自动测试在图表 19 的左侧显示了在制动过程中?#26800;?#19968;个 ABS 控制循环产生 的最大速度差的比较。很明显,黏性联结器减小了速度差。当黏性联结器抵消 YMR ?#20445;?#35201;求操纵车轮角在制动第一秒钟从 39 度增加到 51 度保?#21046;?#36710;在?#27605;?#26041;向上 (图表 19,中部) 。由于大多数汽车和 ABS 制造厂家认为 90 度是达到临界状态的 限制,所以这能被接受。最后,在高 值的一侧通过黏性联结器产生的一个增加? 的自锁扭转力。车轮制动力,一辆稍稍的高一些的汽车保持减速(图表 19 ?#20063;啵?6 总结 总之,黏性联结器在前轴差速器的试用能被证实。它也明确地影响整个汽车 的控制和稳定,只是稍微地,但是可以接受的在扭转力操纵上的影响。 为了减小不想要的扭转力操纵的影响一个基本的设计准则被给出 1 由于纵向载荷改变产生的警觉反应必须尽可能的小 2 主销轴线和车轮中心之间的距离必须尽可能的小 3 垂直弯曲角变化范围应该接近零(或者为负值) 4 两侧的垂直弯曲角应该一样 5 侧轴应该等长 在扭转力操纵上小的影响是联结处的干扰常数不管什么理由这个常数的理想 值是零。带有和不带有 ABS 的制动系统仅仅是黏性联结器不重要的影响。在前轮 驱动的汽车上通过黏性的限制滑动差速器牵引力有着很重要的改善。 前轮驱动汽车独立的转向装置的行动方式在操纵状态的方向下被黏性限制滑 动差速器稍稍地影响。在转弯过程中节气门关闭和加速改进的反应使前轴安装有 黏性联结器的汽车更稳定,更可预见而且更安全。 附件 2外文原文(复印件) 5.EFFECT ON CORNERING Viscous 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. Figure 10 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 see figure 10. 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. this is shown in figure 12 Figure 12 tractive 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 . Figures 13 and 14 show the results of acceleration tests during steady state cornering with an open differential and with viscous limited-slip differential . Figure 13 acceleration characteristics for a front-wheel drive vehicle with an open differential on wet asphalt at a radius of 40m fixed steering wheel angle throughout test. Figure 14 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 while the2/sm vehicle with the viscous coupling reaches an average of 2.3 limited by engine-power. In these tests, the maximum speed 2/ 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, which is illustrated in Figure 12. the imbalance in the front wheel tractive forces results in a yaw moment acting in direction of the turn, countering the understeer.CSDM 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, which is illustrated for the viscous equipped vehicle in Figure 15. Figure 15Baraking Forces for a Front-Wheel Drive Vehicle with Viscous Limited-Slip Differential Immediately after a Throttle-off Maneuver While Cornering As 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 between the front-wheels applied around the center fB of gravity of the vehicle causes a yaw moment that counteracts the GCM0 normal turn-in reaction. When 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. Figure 16 Throttle-off Characteristics for a Front-Wheel Drive Vehicle with an open Differential on Wet Asphalt at a Radius of 40m Open Loop Figure 17Throttle-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 Time0 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. Although this might be considered as a negative effect and can easily be corrected when setting the YMR algorithm for a vehicle with a front viscous coupling, vehicle tests have proved that the influence is so slight that no special development of new ABS/YMR algorithms are actually needed. Some typical averaged test results are summarized in Figure 19. figure 19 results form ABS braking tests with YMR on split-μVo50 mph, 3rd Gear, closed loop in figure 19 on the left a comparison of the maximum speed difference which occurred in the first ABS control cycle during braking is shown. It is obvious that the viscous coupling is reducing this speed difference. As the viscous coupling counteracts the YMR, the required steering wheel angle to keep the vehicle in straight direction in the first second of braking increased from 39 to 51 figure 19,middle. Since most vehicle and ABS manufacturers consider 90 to be the critical limit, this can be tolerated. Finally, as the self-locking torque produced by the viscous coupling causes an increase in high-. Wheel braking force, a slightly higher vehicle deceleration was maintainedfigure 19,right. 6.SUMMARY in conclusion,it can be established that the application of a viscous coupling in a front-axle differential. It also positively influences the complete vehicle handling and stability , with only slight, but acceptable influence on torques-steer. To reduce unwanted torque-steer effects a basic set of design rules have been established ? Toe-in response due to longitudinal load change must be as small as possible . ? Distance between king-pin axis and wheel center has to be as small as possible. ? Vertical bending angle-rang should be centered around zeroor negative. ? vertical bending angles should be the same for both sides. ? Sideshafts should be of equal length. Of minor influence on torque-steer is the joint disturbance lever arm which should be ideally zero for other reasons anyway. Braking with and without ABS is only negligibly influenced by the viscous coupling. Traction is significantly improved by the viscous limited slip differential in a front-wheel drive vehicle. The self-steering behavior of a front-wheel drive vehicle is slightly influenced by a viscous limited slip differential in the direction of understeer. The improved reactions to throttle-off and acceleration during cornering make a vehicle with viscous coupling in the front-axle considerably more stable, more pre

注意事项

本文(外文翻译--黏性连接器用作前轮驱动限制滑移差速器对汽车牵引和操纵的影响-汽车设计.doc)为本站会员(天天文库)主动上传,文库吧仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知文库吧(发送邮件至[email protected]或直接QQ联系客服),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。




关于我们 - 网站声明 - 网?#38236;?#22270; - 资源地图 - 友情链接 - 网?#31350;?#26381;点击这里,给文库吧发消息,QQ:1548881058 - 联系我们

[email protected] 2015-2021 wenkub网站版权所有
经营许可证编号:鄂ICP备17016276 

收起
展开
北京pk10双面盘预测
<acronym id="6i0ao"><small id="6i0ao"></small></acronym>
<acronym id="6i0ao"><center id="6i0ao"></center></acronym>
<acronym id="6i0ao"><small id="6i0ao"></small></acronym>
<acronym id="6i0ao"><center id="6i0ao"></center></acronym>