重型载货汽车的悬架系统结构的设计【4张图纸】【优秀】

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重型载货汽车的悬架系统结构的设计62页 25000字数+说明书+外文翻译+开题报告+4张CAD图纸减振器.exb减振器装配图.dwg外文翻译-汽车悬架如何工作.doc悬架原理图.dwg悬架原理图.exb悬架空气弹簧.dwg悬架空气弹簧.exb悬架高度控制阀.exb悬架高度控制阀装配图.dwg目录.doc重型载货汽车的悬架系统结构的设计开题报告.doc重型载货汽车的悬架系统结构的设计论文.doc摘要随着国民经济的高速发展，我国公路运输需求将在一段较长时间内保持持续增长。重型载货汽车品种多、应用广泛，在国民经济建设中发挥巨大作用。由于重型汽车工作条件比较恶劣、弯道多、坡路多、转弯半径小，车辆频繁转向与制动，并长期在满载、振动与冲击载荷下工作，振动都比较强烈。为保证车辆具有良好的高速行驶平顺性，实现质量高运输，并减小对路面的破坏程度，先进的车辆悬架技术在重型卡车上被广泛研究和采用。空气悬架由弹性元件、导向装置、减振器、缓冲块和横向稳定器等组成，囊式空气弹簧是弹性元件其中一种，它含有帘布层结构的橡胶气囊内冲入空气，并以空气为介质，利用空气可以压缩的特点来实现弹性作用。通过高度控制阀，来保证车身高度不随汽车载荷变化而变化，保证汽车的平顺性和稳定性。减振器是保证汽车在使用期限行驶平顺性的性能稳定的主要元件。关键词：导向装置；空气弹簧；高度控制阀；减振器ABSTRACTWith the high-speed development of domestic economy,our nations road transportation will keep increasing quickly and continuously in a long periodHeavy trucks play an essential role in the economy construction for its merits，such as abundant sorts，comprehensive applicationUsually the work conditions of the heavy truck is execrable，which is full of bend road，slope road；Truck must swerve with small radius，turn and brake high frequently，and it is also used under the condition of fullload vibration and striking,the vibration is serious，which is dangerous to driversbodyIn order to provide the heavy truck with high-speed ride comfort and quality of transit，at the same time decrease the disastrous impact to the road，advanced vehicle suspension technology has been invesfigated applied extensively in heavy truck industry.Air suspension of elastic component, guiding device, shock absorber, transverse stabilizer blocks and a buffer, cystic components, such as air spring flexible components, it contains one layer structure of air curtain inside irruptive air, rubber and air as medium, the characteristics of air can be compressed to achieve flexibility. Through the height valve body height, to ensure that no changes with the automobile loading, guarantee the stability and car ride. Car shock absorber is to ensure that the use of the performance period of ride comfort and stability of the main components.Key words：orientation device；air spring；height control valves；shock absorber目录前言11 绪论21.1 悬架的概述21.2 悬架的分类41.3 重型载货汽车悬架系统目前的工作状况51.4 悬架技术的研究现状及发展趋势61.4.1悬架技术的研究现状61.4.2悬架技术的发展趋势61.4.3悬架设计的技术要求72 空气悬架结构82.1 空气悬架结构简介82.1.1空气悬架系统的基本结构82.1.2空气弹簧的类型92.1.3导向机构102.1.4高度控制阀102.2 空气悬架系统的工作原理103 悬架主要参数的确定123.1 载货汽车的结构参数123.2 悬架静挠度123.3 悬架动挠度143.4 悬架弹性特性144 弹性元件的设计164.1 空气弹簧力学性能174.1.1空气弹簧刚度计算174.1.2空气弹簧固有频率的计算194.1.3空气弹簧的刚度特性分析204.2 高度控制阀215 悬架导向机构的设计235.1 悬架导向机构的概述235.2 横向稳定杆的选择245.3 侧顷力臂的计算方法255.4 稳定杆的角刚度计算265.5 悬架的侧倾角校核276 减振器机构类型及主要参数的选择计算296.1 分类296.2 主要参数的选择计算317 技术与经济性分析368 结论38参考文献39致谢40附录A 译文41附录B 外文原文48机械装置的基本规律指出：载货汽车良好的舒适性，操纵稳定性及良好的承载能力在使用定刚度和定阻尼减震器的传统悬架中是不能同时满足的。因此，传统的悬架在设计过程中不可避免的要进行乘坐舒适性和操纵稳定性的折衷，尽管近年来传统悬架在结构上的不断更新和完善，采用优化设计方法进行设计，已使汽车(特别是轿车)的乘坐舒适性和操纵稳定性有很大提高，例如横臂式独立悬架、纵臂式独立悬架、车轮沿主销移动的悬架(烛式和麦弗逊式)等等的采用，但传统悬架系统仍然受到许多限制，如最终设计的悬架参数(弹簧刚度、减振器阻尼系数)是不可调节的，致使传统悬架系统只能保证汽车在一种特定的道路和速度条件下达到性能最优的折衷。1.4.2悬架技术的发展趋势当前在大型商用汽车、半挂车中采用空气悬架系统越来越多。空气悬架突出的优点是平顺性好，维修少，寿命长，对承运的乘客和货物的保护比钢板弹簧悬架有着很大的提高，而对整车和路面的损坏程度也大大减少。钢板弹簧在不同的载荷下产生不同的弯曲，这样会导致整车到地面的距离总是在发生变化，如果保持弹簧的弹性而增加载荷的话，这会降低弹簧的固有频率甚至使弹簧的特性发生改变。空气弹簧基于空气的可压缩性，封闭在气囊里的空气是弹性元件，空气弹簧通过不同气囊的压力来平衡不同的载荷。空气弹簧的固有频率稳定，因此它的弹性性能也稳定，这样就意味着空气弹簧更加的接近理想状态。随着我国高速公路的迅速发展，公路运输量的增加，对汽车性能的要求也越来越高，空气悬架凭着其自身的优越性能在货车上的应用必将越来越广泛。另外，随着重型载货汽车对路面的破坏机理的研究及认识的进一步加深，以及政府对高速路养护的进一步重视，空气悬架在重型货车上的应用也必将进一步增加。因此，对空气悬架的设计进行深入的研究也显得越来越重要。1.4.3悬架设计的技术要求对悬架提出的设计要求有：（1）保证汽车有良好的行驶平顺性（2）具有适合的衰减振动的能力（3）保证汽车具有良好的操纵稳定性（4）汽车制动或加速时，要保证车身稳定性，减少车身纵倾，转弯时车身侧倾角要适合（5）有良好的隔声能力（6）结构紧凑、占用空间尺寸要小（7）可靠地传递车身与车轮之间的各种力和力矩，在满足零部件质量要小的同时，还要保证有足够的强度和寿命

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关键词：: 重型载货汽车悬架系统结构设计图纸优秀优良

资源描述：

重型载货汽车的悬架系统结构的设计

62页 25000字数+说明书+外文翻译+开题报告+4张CAD图纸

减振器.exb

减振器装配图.dwg

外文翻译--汽车悬架如何工作.doc

悬架原理图.dwg

悬架原理图.exb

悬架空气弹簧.dwg

悬架空气弹簧.exb

悬架高度控制阀.exb

悬架高度控制阀装配图.dwg

目录.doc

重型载货汽车的悬架系统结构的设计开题报告.doc

重型载货汽车的悬架系统结构的设计论文.doc

摘要

　　　随着国民经济的高速发展，我国公路运输需求将在一段较长时间内保持持续增长。重型载货汽车品种多、应用广泛，在国民经济建设中发挥巨大作用。由于重型汽车工作条件比较恶劣、弯道多、坡路多、转弯半径小，车辆频繁转向与制动，并长期在满载、振动与冲击载荷下工作，振动都比较强烈。为保证车辆具有良好的高速行驶平顺性，实现质量高运输，并减小对路面的破坏程度，先进的车辆悬架技术在重型卡车上被广泛研究和采用。

　　　空气悬架由弹性元件、导向装置、减振器、缓冲块和横向稳定器等组成，囊式空气弹簧是弹性元件其中一种，它含有帘布层结构的橡胶气囊内冲入空气，并以空气为介质，利用空气可以压缩的特点来实现弹性作用。通过高度控制阀，来保证车身高度不随汽车载荷变化而变化，保证汽车的平顺性和稳定性。减振器是保证汽车在使用期限行驶平顺性的性能稳定的主要元件。

关键词：导向装置；空气弹簧；高度控制阀；减振器

ABSTRACT

　　　With the high-speed development of domestic economy,our nation’s road transportation will keep increasing quickly and continuously in a long period．Heavy trucks play an essential role in the economy construction for its merits，such as abundant sorts，comprehensive application．Usually the work conditions of the heavy truck is execrable，which is full of bend road，slope road；Truck must swerve with small radius，turn and brake high frequently，and it is also used under the condition of full—load vibration and striking,the vibration is serious，which is dangerous to drivers’body．In order to provide the heavy truck with high-speed ride comfort and quality of transit，at the same time decrease the disastrous impact to the road，advanced vehicle suspension technology has been invesfigated applied extensively in heavy truck industry.

　　Air suspension of elastic component, guiding device, shock absorber, transverse stabilizer blocks and a buffer, cystic components, such as air spring flexible components, it contains one layer structure of air curtain inside irruptive air, rubber and air as medium, the characteristics of air can be compressed to achieve flexibility. Through the height valve body height, to ensure that no changes with the automobile loading, guarantee the stability and car ride. Car shock absorber is to ensure that the use of the performance period of ride comfort and stability of the main components.

Key words：orientation device；air spring；height control valves；shock absorber

前言1

1 绪论2

1.1 悬架的概述2

1.2 悬架的分类4

1.3 重型载货汽车悬架系统目前的工作状况5

1.4 悬架技术的研究现状及发展趋势6

1.4.1悬架技术的研究现状6

1.4.2悬架技术的发展趋势6

1.4.3悬架设计的技术要求7

2 空气悬架结构8

2.1 空气悬架结构简介8

2.1.1空气悬架系统的基本结构8

2.1.2空气弹簧的类型9

2.1.3导向机构10

2.1.4高度控制阀10

2.2 空气悬架系统的工作原理10

3 悬架主要参数的确定12

3.1 载货汽车的结构参数12

3.2 悬架静挠度12

3.3 悬架动挠度14

3.4 悬架弹性特性14

4 弹性元件的设计16

4.1 空气弹簧力学性能17

4.1.1空气弹簧刚度计算17

4.1.2空气弹簧固有频率的计算19

4.1.3空气弹簧的刚度特性分析20

4.2 高度控制阀21

5 悬架导向机构的设计23

5.1 悬架导向机构的概述23

5.2 横向稳定杆的选择24

5.3 侧顷力臂的计算方法25

5.4 稳定杆的角刚度计算26

5.5 悬架的侧倾角校核27

6 减振器机构类型及主要参数的选择计算29

6.1 分类29

6.2 主要参数的选择计算31

7 技术与经济性分析36

8 结论38

参考文献39

致谢40

附录A 译文41

附录B 外文原文48

　　　机械装置的基本规律指出：载货汽车良好的舒适性，操纵稳定性及良好的承载能力在使用定刚度和定阻尼减震器的传统悬架中是不能同时满足的。因此，传统的悬架在设计过程中不可避免的要进行乘坐舒适性和操纵稳定性的折衷，尽管近年来传统悬架在结构上的不断更新和完善，采用优化设计方法进行设计，已使汽车(特别是轿车)的乘坐舒适性和操纵稳定性有很大提高，例如横臂式独立悬架、纵臂式独立悬架、车轮沿主销移动的悬架(烛式和麦弗逊式)等等的采用，但传统悬架系统仍然受到许多限制，如最终设计的悬架参数(弹簧刚度、减振器阻尼系数)是不可调节的，致使传统悬架系统只能保证汽车在一种特定的道路和速度条件下达到性能最优的折衷。

1.4.2悬架技术的发展趋势

　　　当前在大型商用汽车、半挂车中采用空气悬架系统越来越多。空气悬架突出的优点是平顺性好，维修少，寿命长，对承运的乘客和货物的保护比钢板弹簧悬架有着很大的提高，而对整车和路面的损坏程度也大大减少。

　　　钢板弹簧在不同的载荷下产生不同的弯曲，这样会导致整车到地面的距离总是在发生变化，如果保持弹簧的弹性而增加载荷的话，这会降低弹簧的固有频率甚至使弹簧的特性发生改变。

　　　空气弹簧基于空气的可压缩性，封闭在气囊里的空气是弹性元件，空气弹簧通过不同气囊的压力来平衡不同的载荷。空气弹簧的固有频率稳定，因此它的弹性性能也稳定，这样就意味着空气弹簧更加的接近理想状态。

　　　随着我国高速公路的迅速发展，公路运输量的增加，对汽车性能的要求也越来越高，空气悬架凭着其自身的优越性能在货车上的应用必将越来越广泛。另外，随着重型载货汽车对路面的破坏机理的研究及认识的进一步加深，以及政府对高速路养护的进一步重视，空气悬架在重型货车上的应用也必将进一步增加。因此，对空气悬架的设计进行深入的研究也显得越来越重要。

1.4.3悬架设计的技术要求

　　　对悬架提出的设计要求有：

　　　（1）保证汽车有良好的行驶平顺性

　　　（2）具有适合的衰减振动的能力

　　　（3）保证汽车具有良好的操纵稳定性

　　　（4）汽车制动或加速时，要保证车身稳定性，减少车身纵倾，转弯时车身侧倾角要适合

　　　（5）有良好的隔声能力

　　　（6）结构紧凑、占用空间尺寸要小

　　　（7）可靠地传递车身与车轮之间的各种力和力矩，在满足零部件质量要小的同时，还要保证有足够的强度和寿命

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内容简介：: 附录A 译文汽车悬架如何工作By William HarrisUniversity of Michigan当人们考虑汽车性能的时候，他们通常认为是马力，扭矩和零到60的加速时间。但是，如果司机无法控制汽车，由一个活塞发动机产生的功率都是无用的。这就是为什么汽车的工程师开始将注意力转向悬挂系统，尽快为他们几乎已经掌握了四冲程内燃机。双横臂独立悬架的本田雅阁轿跑车2005年汽车悬架的工作是尽量在轮胎和路面之间提供良好的操纵稳定性，并确保乘客的舒适度。在这篇文章中，我们将探讨汽车悬架如何的工作，他们已经逐渐发展起来，这些年来，那里的悬架设计在未来的发展方向。1.车辆动力学如果道路是完全平坦，没有违规行为，就没有必要停牌。但远离道路平坦，即使是刚铺好的公路有细微的缺陷，与汽车的车轮相联系的。它的这些缺陷聚焦于车轮。根据牛顿运动定律，所有部队都大小和方向。一个在路上碰到导致车轮向上和向下移动到垂直路面。当然大小，取决于是否是惊人的一个巨大的车轮碰撞或一点点。无论哪种方式，车轮垂直加速度的经验，因为它传递了一个缺陷。如果没有中间结构，所有车轮的垂直能量转移到车架，这在同一方向移动。在这种情况下，车轮与路面可以完全失去联系。接着，在向下的重力，车轮可以大满贯回路面。你需要的是一个系统，将吸收的能量垂直加速轮，使画面和身体不受干扰，而车轮按照道路颠簸。对在工作力量上开动的汽车上被称为车辆动力学研究，你需要了解其中一些概念，以明白为什么暂停把必要摆在首位。大多数汽车工程师从两个角度考虑的一个移动的汽车的动态：1）乘坐汽车的能力，理顺了不平坦的道路2）处理汽车的能力，安全地加速，刹车和角落这两个特点可以进一步说明在三个重要的原则道路隔离，道路控股和转弯。下表描述了这些原则和工程师如何尝试解决每一个独特的挑战。汽车的悬挂其各个组成部分，提供了解决方案，所有描述。2.底盘系统一辆汽车的悬挂，其实就是在底盘，其中包括对汽车底下找到了所有重要系统的一部分。图2-1底盘这些制度包括：1）框架结构，承载组件，支持汽车的引擎和身体，这反过来又受到暂停支持2）悬挂系统安装支持重量，吸收冲击和削弱，并帮助维持轮胎接触3）转向系统底盘，使驾驶者和直接指导的车辆4）轮胎和轮子部件的抓地力，使汽车运动的可能和途径/或与路面摩擦力因此，暂停只是在任何车辆的主要系统之一。考虑到这一大画面的概述，它的时间来看看三个基本组成部分的任何中止：弹簧，减震器和防摇杆。3.弹簧1）线圈弹簧这是弹簧的最常见的类型，而且在本质上是重型扭杆围绕一个轴圈。线圈弹簧压缩和扩展，吸收了车轮的方案。2）钢板弹簧这个弹簧型的多层次金属称为“叶”联系在一起，作为一个独立的单元包括。钢板弹簧被首次应用于马车，以及对最符合美国的汽车，直到1985年。他们今天仍在使用的最卡车和重型车辆。3）扭杆扭杆使用一种扭钢筋的性能提供线圈弹簧般的表现。这是他们的工作：一个是最后一个栏固定在车架。另一端是连接到一个叉骨，它就像一个杠杆，移动垂直扭杆行为。当点击一个车轮撞，垂直运动，是转移到叉骨，然后通过撬起行动，扭杆。扭杆然后沿其轴线曲折提供弹簧力。欧洲汽车制造商广泛使用这个系统一样，在美国惠普和克莱斯勒在20世纪50年代和60年代通过。4）空气弹簧空气弹簧，其中一间的轮子和汽车的空气圆柱腔体的位置组成，利用空气的压缩品质吸收车轮的震动。这个概念其实比一个多世纪的历史，可以对马拉儿童车找到。从这个时代却是从空气弹簧充气，皮革隔膜，就像一个波纹管，他们是在20世纪30年代模压橡胶空气弹簧取代。基于在弹簧位于上车即车轮之间的框架工程师常常感到方便谈谈簧载质量和簧下质量。4. 弹簧和簧下质量跳跃质量是对弹簧支撑的汽车质量，而簧下质量是松散的之间的道路和悬架弹簧质量定义。弹簧刚度的影响如何回应，而簧载质量正在驾驶汽车。松散的弹簧汽车，如豪华轿车（认为林肯城市车），可以吞下振动，并提供一个超级平稳，但是，这样的车很容易潜水和制动和加速并趋于身体晃动转弯。紧紧弹簧车，如跑车（认为马自达Miata身上），在颠簸的道路，但他们尽量减少身体的方案很好，这意味着他们可以更积极推动各地角落。因此，虽然自己看起来简单的弹簧装置，设计和实施他们的汽车乘客舒适度的平衡与处理是一项复杂的任务。而为了让事情更加复杂，弹簧不能单独提供一个完美的平稳运行。由于弹簧在吸收能量是巨大的，但它不是在散热良好。其他构筑物，如阻尼器众所周知，必须这样做。5. 减震器除了抑制结构是现在用的，汽车弹簧将扩大和失控的速度释放的能量是从一肿块吸收。弹簧将继续反弹，直到所有的能量在其自然频率最初投入到IT用完。建立一个单独的弹簧悬架会使乘坐一个非常有弹性，并根据地形，难以控制汽车。输入减震器和缓冲器，一个装置，通过控制作为一个过程称为抑制有害弹簧的方案。减震器慢下来，减少转化为热能，可以通过液压油消退了悬架运动动能的振动运动的幅度。要理解这是如何工作，最好找一个减震器内看到它的结构和功能。一个减震器基本上是安装在车轮架和车轮之间的油泵。上部安装的冲击连接到帧（即弹簧的重量），而较低的安装连接到轴，靠近轮（即没有装弹簧的重量）。在双管设计，对减震器，上部安装连接到活塞杆，而这又是连接到一个活塞，从而在一个充满液压油与管坐在最常见的类型之一。内管被称为压力管，外管，是已知的储备管。超额准备金管店液压油。当汽车车轮在路上遇到碰撞，造成对线圈弹簧的伤害，弹簧的能量转移到减震器上安装通过，穿越活塞杆和活塞进入。口穿孔的活塞，使液体泄漏，活塞上下移动，通过在压力管。由于孔比较小，只有少量的液体承受很大的压力，经过。这将降低活塞，从而减慢弹簧。减震器工作在两个周期压缩循环和周期延长。压缩周期内发生的活塞向下移动，在下面的压缩腔活塞液压油。延长周期发生作为朝着压力管顶部的活塞动作，压在上面的活塞腔液。一个典型的汽车或轻型卡车将其压缩比在其循环周期延长更多的阻力。考虑到这一点，压缩周期控制车辆的簧下重量方案，而延长控制重，弹簧的重量。所有现代的减震器是速度敏感悬浮移动的速度就越快，越阻力减震器规定。这使得冲击，以适应道路条件和控制可能出现不需要的方案在行驶的车辆，包括弹跳，摇摆，刹车和加速。6.Struts和防摇杆另一种常见的阻尼结构是支撑基本上是一个减震器安装在一个弹簧。它的执行两项工作：他们提供这样一个减震器阻尼作用，并为他们提供车辆悬挂的支撑结构。这意味着提供一个多支柱减震器，不支持车重一点他们只控制在哪是在一辆汽车的重量转移的速度，而不是本身的重量。图6-1共同支撑设计由于冲击有这么多跟一辆汽车的处理，他们可以被认为是关键的安全功能。磨损冲击可以让过多的车辆从一侧重量转移到一边，从前到后。这降低了轮胎的抓地力能力的道路，以及处理和制动性能。7.防摇杆防摇杆（也称为防侧倾杆）是用于减震器一起给一个移动的汽车额外的稳定。一种防摇杆是一个金属棒，跨越整个桥和有效地加入每一个暂停方共同努力。当在一个车轮悬架向上和向下移动，防摇杆转让转移到其他车轮。这将创建一个更公平的平顺性和减少汽车摇摆。特别是，它斗争的一项关于暂停其汽车滚装船，因为它的角落。基于这个原因，今天几乎所有的汽车都作为标准配置防摇装置的杆机构，但如果他们没有，包可以很容易地安装在任何时候的杆机构。8.未来的汽车悬架虽然有增强和改善了弹簧和减震器，但汽车悬架的基本设计经过多年来的没有一个显着的变化。但是这要改变一个品牌，新的悬挂设计构思的Bose在相同的Bose声技术方面的创新而闻名，所有已知的介绍。一些专家甚至于说，Bose是悬浮在汽车悬架以来最大的一个全独立设计推出的进步。图 8-1前悬架模块它是如何工作的，Bose在每个系统使用一个传统的冲击和弹簧安装轮子代替线性电磁马达（LEM的）。放大器提供电力，在这样一个权力与每个系统的压缩再生方式的发动机。该发动机的主要好处是，它们不是由传统的惯性流体的阻尼器固有的限制。作为一个结果，LEM的可扩展和压缩在一个更大的速度，几乎消除了所有客舱震动。该轮的议案能够如此精细的控制，该车体保持水平，不论是什么在方向盘的情况。在LEM的也可以抵消车身议案，而加速，刹车和转弯，使司机的控制更大的责任感。不幸的是，这种模式暂停将无法使用，直到2009年，将在一个或多个高档豪华车提供。在此之前，司机必须依靠可靠的真实的经得起百年考验的悬挂。附录B 外文原文How Car Suspensions WorkBy William HarrisUniversity of MichiganWhen people think of automobile performance, they normally think of horsepower, torque and zero-to-60 acceleration. But all of the power generated by a piston engine is useless if the driver cant control the car. Thats why automobile engineers turned their attention to the suspension system almost as soon as they had mastered the four-stroke internal combustion engine.Double-wishbone suspension on Honda Accord 2005 CoupeThe job of a car suspension is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to ensure the comfort of the passengers. In this article, well explore how car suspensions work, how theyve evolved over the years and where the design of suspensions is headed in the future.1. Vehicle Dynamics If a road were perfectly flat, with no irregularities, suspensions wouldnt be necessary. But roads are far from flat. Even freshly paved highways have subtle imperfections that can interact with the wheels of a car. Its these imperfections that apply forces to the wheels. According to Newtons laws of motion, all forces have both magnitude and direction. A bump in the road causes the wheel to move up and down perpendicular to the road surface. The magnitude, of course, depends on whether the wheel is striking a giant bump or a tiny speck. Either way, the car wheel experiences a vertical acceleration as it passes over an imperfection.Without an intervening structure, all of wheels vertical energy is transferred to the frame, which moves in the same direction. In such a situation, the wheels can lose contact with the road completely. Then, under the downward force of gravity, the wheels can slam back into the road surface. What you need is a system that will absorb the energy of the vertically accelerated wheel, allowing the frame and body to ride undisturbed while the wheels follow bumps in the road.The study of the forces at work on a moving car is called vehicle dynamics, and you need to understand some of these concepts in order to appreciate why a suspension is necessary in the first place. Most automobile engineers consider the dynamics of a moving car from two perspectives:1)Ride - a cars ability to smooth out a bumpy road2)Handling - a cars ability to safely accelerate, brake and corner These two characteristics can be further described in three important principles - road isolation, road holding and cornering. The table below describes these principles and how engineers attempt to solve the challenges unique to each.A cars suspension, with its various components, provides all of the solutions described.2.The Chassis SystemThe suspension of a car is actually part of the chassis, which comprises all of the important systems located beneath the cars body. figure 2-1 ChassisThese systems include: 1) The frame - structural, load-carrying component that supports the cars engine and body, which are in turn supported by the suspension 2) The suspension system - setup that supports weight, absorbs and dampens shock and helps maintain tire contact 3) The steering system - mechanism that enables the driver to guide and direct the vehicle 4) The tires and wheels - components that make vehicle motion possible by way of grip and/or friction with the road So the suspension is just one of the major systems in any vehicle. With this big-picture overview in mind, its time to look at the three fundamental components of any suspension: springs, dampers and anti-sway bars. 3.Springs Todays springing systems are based on one of four basic designs:1）Coil springs - This is the most common type of spring and is, in essence, a heavy-duty torsion bar coiled around an axis. Coil springs compress and expand to absorb the motion of the wheels.2）Leaf springs - This type of spring consists of several layers of metal (called leaves) bound together to act as a single unit. Leaf springs were first used on horse-drawn carriages and were found on most American automobiles until 1985. They are still used today on most trucks and heavy-duty vehicles.3）Torsion bars - Torsion bars use the twisting properties of a steel bar to provide coil-spring-like performance. This is how they work: One end of a bar is anchored to the vehicle frame. The other end is attached to a wishbone, which acts like a lever that moves perpendicular to the torsion bar. When the wheel hits a bump, vertical motion is transferred to the wishbone and then, through the levering action, to the torsion bar. The torsion bar then twists along its axis to provide the spring force. European carmakers used this system extensively, as did Packard and Chrysler in the United States, through the 1950s and 1960s.4）Air springs - Air springs, which consist of a cylindrical chamber of air positioned between the wheel and the cars body, use the compressive qualities of air to absorb wheel vibrations. The concept is actually more than a century old and could be found on horse-drawn buggies. Air springs from this era were made from air-filled, leather diaphragms, much like a bellows; they were replaced with molded-rubber air springs in the 1930s.Based on where springs are located on a car - i.e., between the wheels and the frame - engineers often find it convenient to talk about the sprung mass and the unsprung mass.4.Sprung and Unsprung MassThe sprung mass is the mass of the vehicle supported on the springs, while the unsprung mass is loosely defined as the mass between the road and the suspension springs. The stiffness of the springs affects how the sprung mass responds while the car is being driven. Loosely sprung cars, such as luxury cars (think Lincoln Town Car), can swallow bumps and provide a super-smooth ride; however, such a car is prone to dive and squat during braking and acceleration and tends to experience body sway or roll during cornering. Tightly sprung cars, such as sports cars (think Mazda Miata), are less forgiving on bumpy roads, but they minimize body motion well, which means they can be driven aggressively, even around corners.So, while springs by themselves seem like simple devices, designing and implementing them on a car to balance passenger comfort with handling is a complex task. And to make matters more complex, springs alone cant provide a perfectly smooth ride. Why? Because springs are great at absorbing energy, but not so good at dissipating it. Other structures, known as dampers, are required to do this.5.Shock AbsorbersUnless a dampening structure is present, a car spring will extend and release the energy it absorbs from a bump at an uncontrolled rate. The spring will continue to bounce at its natural frequency until all of the energy originally put into it is used up. A suspension built on springs alone would make for an extremely bouncy ride and, depending on the terrain, an uncontrollable car.Enter the shock absorber, or snubber, a device that controls unwanted spring motion through a process known as dampening. Shock absorbers slow down and reduce the magnitude of vibratory motions by turning the kinetic energy of suspension movement into heat energy that can be dissipated through hydraulic fluid. To understand how this works, its best to look inside a shock absorber to see its structure and function.A shock absorber is basically an oil pump placed between the frame of the car and the wheels. The upper mount of the shock connects to the frame (i.e., the sprung weight), while the lower mount connects to the axle, near the wheel (i.e., the unsprung weight). In a twin-tube design, one of the most common types of shock absorbers, the upper mount is connected to a piston rod, which in turn is connected to a piston, which in turn sits in a tube filled with hydraulic fluid. The inner tube is known as the pressure tube, and the outer tube is known as the reserve tube. The reserve tube stores excess hydraulic fluid.When the car wheel encounters a bump in the road and causes the spring to coil and uncoil, the energy of the spring is transferred to the shock absorber through the upper mount, down through the piston rod and into the piston. Orifices perforate the piston and allow fluid to leak through as the piston moves up and down in the pressure tube. Because the orifices are relatively tiny, only a small amount of fluid, under great pressure, passes through. This slows down the piston, which in turn slows down the spring.Shock absorbers work in two cycles - the compression cycle and the extension cycle. The compression cycle occurs as the piston moves downward, compressing the hydraulic fluid in the chamber below the piston. The extension cycle occurs as the piston moves toward the top of the pressure tube, compressing the fluid in the chamber above the piston. A typical car or light truck will have more resistance during its extension cycle than its compression cycle. With that in mind, the compression cycle controls the motion of the vehicles unsprung weight, while extension controls the heavier, sprung weight.All modern shock absorbers are velocity-sensitive - the faster the suspension moves, the more resistance the shock absorber provides. This enables shocks to adjust to road conditions and to control all of the unwanted motions that can occur in a moving vehicle, including bounce, sway, brake dive and acceleration squat.6.Struts and Anti-sway Bars Another common dampening structure is the strut - basically a shock absorber mounted inside a coil spring. Struts perform two jobs: They provide a dampening function like shock absorbers, and they provide structural support for the vehicle suspension. That means struts deliver a bit more than shock absorbers, which dont support vehicle weight - they only control the speed at which weight is transferred in a car, not the weight itself. figure 6-1 Common strut designBecause shocks and struts have so much to do with the handling of a car, they can be considered critical safety features. Worn shocks and struts can allow excessive vehicle-weight transfer from side to side and front to back. This reduces the tires ability to grip the road, as well as handling and braking performance. 7.Anti-sway Bars Anti-sway bars (also known as anti-roll bars) are used along with shock absorbers or struts to give a moving automobile additional stability. An anti-sway bar is a metal rod that spans the entire axle and effectively joins each side of the suspension together. When the suspension at one wheel moves up and down, the anti-sway bar transfers movement to the other wheel. This creates a more level ride and reduces vehicle sway. In particular, it combats the roll of a car on its suspension as it corners. For this reason, almost all cars today are fitted with anti-sway bars as standard equipment, although if theyre not, kits make it easy to install the bars at any time. 8.The Future of Car Suspensions While there have been enhancements and improvements to both springs and shock absorbers, the basic design of car suspensions has not undergone a significant evolution over the years. But all of thats about to change with the introduction of a brand-new suspension design conceived by Bose - the same Bose known for its innovations in acoustic technologies. Some experts are going so far as to say that the Bose suspension is the biggest advance in automobile suspensions since the introduction of an all-independent design. figure 3-1 Suspension Front ModuleHow does it work? The Bose system uses a linear electromagnetic motor (LEM) at each wheel in lieu of a conventional shock-and-spring setup. Amplifiers provide electricity to the motors in such a way that their power is regenerated with each compression of the system. The main benefit of the motors is that they are not limited by the inertia inherent in conventional fluid-based dampers. As a result, an LEM can extend and compress at a much greater speed, virtually eliminating all vibrations in the passenger cabin. The wheels motion can be so finely controlled that the body of the car remains level regardless of whats happening at the wheel. The LEM can also counter

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