本科畢業(yè)設(shè)計(jì)中期報(bào)告填表日期： 年 5 月 8 日學(xué)院（部） 班 級 學(xué)生姓名 課題名稱：五噸貨車底盤布置及后懸架設(shè)計(jì)課題主要任務(wù)：調(diào)研分析我國及國外中型卡車發(fā)展的趨勢，以及在原有中型卡車基礎(chǔ)上進(jìn)行設(shè)計(jì)的必要性；課題的主要任務(wù)就是對卡車底盤進(jìn)行總布置，對后懸架系統(tǒng)進(jìn)行設(shè)計(jì)并對設(shè)計(jì)懸架系統(tǒng)各部件技術(shù)參數(shù)做計(jì)算校核。1、簡述開題以來所做的具體工作和取得的進(jìn)展或成果① 掌握汽車底盤布置及懸架設(shè)計(jì)的一般步驟。② 總體布置方案確定根據(jù)給定數(shù)據(jù)對卡車底盤的總布置形式作確定③ 后懸架系統(tǒng)方案確定及設(shè)計(jì)計(jì)算軸荷軸距等對后懸架系統(tǒng)各主要部分進(jìn)行設(shè)計(jì)。④ 設(shè)計(jì)的驗(yàn)算，校核根據(jù)設(shè)計(jì)思路，結(jié)合機(jī)械理論和力學(xué)知識對后懸架各部件作剛度、強(qiáng)度等校核計(jì)算。⑤ 整理材料，編寫設(shè)計(jì)說明書。2、下一步的主要研究任務(wù)，具體設(shè)想與安排主要的研究任務(wù)：修改完善設(shè)計(jì)說明書及裝配圖、主要零件圖的繪制。具體安排：先完成設(shè)計(jì)說明書的撰寫，然后繪制總布置圖、及后懸掛主要部分的裝配圖，最后完成一系列零件圖。3、存在的具體問題在設(shè)計(jì)的過程中，對于卡車底盤布置及后懸架系統(tǒng)設(shè)計(jì)中某些經(jīng)驗(yàn)公式，經(jīng)驗(yàn)選型，經(jīng)驗(yàn)數(shù)據(jù)等尚未了解，還須多查閱資料。4、指導(dǎo)教師對該生前期研究工作的評價(jià)指導(dǎo)教師簽名：日 期：英文原文How Car Suspension WorkBy William HarrisUniversity of MichiganWhen people thinly 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 drier can't control the car. That's 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, we'll explore how car Suspensions work,how they're evolved over the years and where the design of suspensions is headed in the future.1 .Vehicle DynamicsIf a road were perfectly t1at, with no irregularities, suspensions wouldn't be necessary. But roads are far from t1at. Even freshly paved highways have subtle imperfections that can interact with the wheels of a car. It's these imperfections that apply forces to the wheels. According to Newton's 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 ca.r wheelexperiences a vertical acceleration as it passes over an imperfection.Without an intervening structure, all of wheel's 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,wheels can slam back into the road surface. What you need is a system that 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 farces at work an a moving car is called vehicle dynamics, and you need to suspension is necessary of need to understand same of these concepts in order to appreciate why a necessary in the first place. Mast automobile engineers consider the moving car Pram two perspectives:1) Ride-a car's ability to smooth out a bumpy road2)Handling-a car's 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 car's 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 car's body.figure 2-1 ChassisThese systems include:1) The frame-structural, load-carrying component that supports the car's engine and body, which are in turn supported by the suspension2)The Suspension system-setup that supports weight, absorbs and dampens shock and helps maintain tire contact3)The steering system-mechanism that enables the driver to guide and direct the vehicle4) The tires and wheels-components that make vehicle motion possible by way of grip and/or friction with the roadSo the suspension is just one of the major systems in any vehicle.With this big-picture overview in mind, it's time to look at the three fundamental components of any suspension: springs, dampers and anti-sway bars.3 .springsToday's springing systems are based on one of four basic design:1)Coil spring-This is the mast common type of spring and is, in essence, a heavy-duty torsion barcoiled around an axis. Coil springs compress and expand to absorb the motion of the wheels.2)Leaf spring-This type of spring consists of several layers of metal (called“l(fā)eaves“) bound together to act as a single unit. Leaf springs were first used on horse-drawn carriages and were found an 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 Gar 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 i5 attached to a wishbone, which acts like a lever that mares 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 farce. European caretakers used this system extensively, as did Packard and Chrysler in the UnitedStates, through the 1950s and 1960s.4)Air springs-Air Springs, which consist of a cylindrical chamber of air positioned between the wheel and the car's body, use the compres5ire qualities of air to absorb wheel vibrations. The concept is actually more than a century old and could be found an 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 an 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 Taws Card, can Swallow bumps and provide a super-smooth ride; however, such a car is prune to dive and squat during braking and acceleration and tends to experience body away 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 can't provide a perfectly smooth ride.W hy? 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 .Shack 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 an springs alone would make for an extremely bouncy ride and,depending an the terrain, an uncontrollable car.Enter the shack 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 lie dissipated through hydraulic fluid. To understand how this works, it's best to look inside a shack 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 springy 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 world 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 mare resistance during its extension cycle than its compression cycle. With that in mind,the compression cycle controls the motion of the vehicle's 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 shacks to adjust to road conditions and to central 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 BarsAnother common dampening structure is the strut two jobs-basically a shock absorber mounted inside a coil spring. Struts perform:They pro}ride a dampening function like shack absorbers, and they provide structural support for the vehicle suspension. That means struts deliver a hit more than shock absorbers, which don't 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 tire's ability to grip the road, as well as handling and braking performance.7.Anti-sway BarsAnti 一 sway bars (also known as anti-roll bars) are used slang 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 maven up and dawn, 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.Far this reason, almost all cars today are fitted with anti 一 sway bars as standard equipment, although if they're not, kits make it easy to install the bars at any time.8.The Future of Car SuspensionWhile there have been enhancements and improvements to both springs and shock absorbers, the basic deign of car suspensions has not undergone a significant evolution over the years. But all of that's about to change with the introduction of a brand-new suspension design conceived by Bole-the same 13ose known for its innovations in acoustic technologies. Some experts are going so far as to say that the Bole suspension is the biggest advance in automobile suspensions since the introduction of an all-independent design.figure 8-1 Suspension Front Modu1eHow does it work? The Base system uses a linear electromagnetic motor (LEMA )at each wheel in lieu of a conventional shock-and 一 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 LE1VI can extend and compress at a much greater speed, virtually eliminating all vibrations in the passenger cabin. The wheel's motion can be so finely controlled that the body of the car remains level regardless of what's happening at the wheel. The LE1VI can also counteract the body motion of the car while accelerating, braking and cornering,giving the driver a greater sense of control.Unfortunately, this paradigm 一 shifting suspension won't be available until 2009 when it will be offered on one or more high-end luxury cars. Until then, drivers will have to rely on the tried-and-true suspension methods that have smoothed out bumpy rides for centuries.中文譯文汽車懸架如何工作By William HarrisUniversity of Michigan當(dāng)人們考慮汽車性能的時(shí)候，他們通常認(rèn)為是馬力，扭知和零到 60 的加速時(shí)。但是，如果司機(jī)無法控制汽車，由一個(gè)活塞發(fā)動機(jī)產(chǎn)生的功率都是無用的。這就是為什么汽車的工程師開始將注意力轉(zhuǎn)向懸掛系統(tǒng)，盡快為他們幾乎已經(jīng)掌握了四沖程內(nèi)燃機(jī)。雙橫臂獨(dú)立懸架的本田雅閣轎跑車 2005 年汽車懸架的工作是盡量在輪胎和路而之間提供良好的操縱穩(wěn)定性，并確保乘客的舒適度。在這篇文章中，我們將探討汽車懸架如何的工作，他們已經(jīng)逐漸發(fā)展起來，這些年來，那里的懸架設(shè)計(jì)在未來的發(fā)展方向。1、車輛動力學(xué)如果道路是完全平坦，沒有違規(guī)行為，就沒有必要停牌。但遠(yuǎn)離道路平坦，即使是剛鋪好的公路有細(xì)微的缺陷，與汽車的車輪相聯(lián)系的。它的這些缺陷聚焦于車輪。根據(jù)牛頓運(yùn)動定律，所有部件都大小和方向。一個(gè)在路上碰到導(dǎo)致車輪向上和向下移動到垂直路面。當(dāng)然大小，取決于是否是驚人的一個(gè)巨大的車輪碰撞或一點(diǎn)點(diǎn)。無論哪種方式，車輪垂直加速度的經(jīng)驗(yàn)，因?yàn)樗鼈鬟f了一個(gè)缺陷。如果沒有中間結(jié)構(gòu)，所有車輪的垂直能量轉(zhuǎn)移到車架，這在同一方向移動。在這種情況下，車輪與路面可以完全失去聯(lián)系。接著，在向下的重力，車輪可以大滿貫回路面。你需要的是一個(gè)系統(tǒng)，將吸收的能量垂直加速輪，使畫面和身體不受干擾，而車輪按照道路顛簸。對在工作力量上開動的汽車上被稱為車輛動力學(xué)研究，你需要了解其中一些概念，以明白為什么暫停把必要擺在首位。大多數(shù)汽車工程師從兩個(gè)角度考慮的一個(gè)移動的汽車的動態(tài):1）乘坐一汽車的能力，理順了不平坦的道路2）處理一汽車的能力，安全地加速，剎車和角落這兩個(gè)特點(diǎn)可以進(jìn)一步說明在三個(gè)重要的原則一道路隔離，進(jìn)路控股和轉(zhuǎn)彎。下表描述了這些原則和工程師如何嘗試解決每一個(gè)獨(dú)特的挑戰(zhàn)。汽車的懸掛其各個(gè)組成部分，提供了解決方案，所有描述。2、底盤系統(tǒng)一輛汽車的懸掛，其實(shí)就是在底盤，其中包括對汽車底下找到了所有重要系統(tǒng)的一部分。圖 2-1 底盤這些制度包括:1）框架一結(jié)構(gòu)，承載組件，支持汽車的引擎和身體，這反過來又受到暫停支持。2）懸掛系統(tǒng)一安裝支持重量，吸收沖擊和削弱，并幫助維持輪胎接觸。3）轉(zhuǎn)向系統(tǒng)一底盤，使駕駛者和直接指導(dǎo)的車輛。4）輪胎和輪子一部件的抓地力，使汽車運(yùn)動的可能和途徑或與路而摩擦力。因此，暫停只是在任何車輛的主要系統(tǒng)之一。考慮到這一大畫面的概述，它的時(shí)間來看看三個(gè)基本組成部分的任何中止，彈簧，減震器和防搖桿。3、彈簧1）線圈彈簧一這是彈簧的最常見的類型，而且在本質(zhì)上是重型扭桿圍繞一個(gè)軸圈。線圈彈簧壓縮和擴(kuò)展，吸收了車輪的方案。2）鋼板彈簧一這個(gè)彈簧型的多層次金屬稱為“葉”聯(lián)系在一起，作為一個(gè)獨(dú)立的單元包括。鋼板彈簧被首次應(yīng)用于馬車，以及對最符合美國的汽車，直到 1985 年。他們今大仍在使用的最卡車和重型車輛。3）扭桿一扭桿使用一種扭鋼筋的性能提供線圈彈簧般的表現(xiàn)。這是他們的工作：一個(gè)是最后一個(gè)欄固定在車架。另一端是連接到一個(gè)叉骨，它就像一個(gè)杠桿，移動垂直扭桿行為。當(dāng)點(diǎn)擊一個(gè)車輪撞，垂直運(yùn)動，是轉(zhuǎn)移到叉骨，然后通過撬起行動，扭桿。扭桿然后沿其軸線曲折提供彈簧力。歐洲汽車制造商廣泛使用這個(gè)系統(tǒng)一樣，在美國惠普和克萊斯勒在 20 世紀(jì) 50 年代和 60 年代通過。4）空氣彈簧一空氣彈簧，其中一間的輪子和汽車的空氣圓柱腔體的位置組成，利用空氣的壓縮品質(zhì)吸收車輪的震動。這個(gè)概念其實(shí)有一個(gè)多世紀(jì)的歷史，可以對馬拉兒童車找到。從這個(gè)時(shí)代卻是從空氣彈簧充氣，皮革隔膜，就像一個(gè)波紋管，他們是在 20 世紀(jì) 30 年代模壓橡膠空氣彈簧取代?；谠趶椈晌挥谏宪囈患窜囕喼g的框架一工程師常常感到方便談?wù)劵奢d質(zhì)量和簧下質(zhì)量。4、彈簧和簧下質(zhì)量跳躍質(zhì)量是對彈簧支撐的汽車質(zhì)量，而簧下質(zhì)量是松散的之間的道躋和懸架彈簧質(zhì)量定義。彈簧剛度的影響如何回應(yīng)，而簧載質(zhì)量正在駕駛汽車。松散的彈簧汽車，如豪華轎車(認(rèn)為林肯城市車) ，可以吞下振動，并提供一個(gè)超級平穩(wěn)，但是，這樣的車很容易潛水和制動和加速并趨于身體晃動轉(zhuǎn)彎。緊緊彈簧車，如跑車(認(rèn)為馬自達(dá) Miata 身上)，在顛簸的道路，但他們盡量減少身體的方案很好，這意味著他們可以更積極推動各地角落。因此，雖然自己看起來簡單的彈簧裝置，設(shè)計(jì)和實(shí)施他們的汽車乘客舒適度的平衡與處理是一項(xiàng)復(fù)雜的任務(wù)。而為了讓事情更加復(fù)雜，彈簧不能單獨(dú)提供一個(gè)完美的平穩(wěn)運(yùn)行。由于彈簧在吸收能量是巨大的，但它不是在散熱良好。其他構(gòu)筑物，如阻尼器眾所周知，必須這樣做。5、減震器除了控制結(jié)構(gòu)是現(xiàn)在用的，汽車彈簧將擴(kuò)大和失控的速度釋放的能量是從一腫塊吸收。彈簧將繼續(xù)反彈，直到所有的能量在其自然頻率最初投入到 IT 用完。建立一個(gè)單獨(dú)的彈簧懸架會使乘坐一個(gè)非常有彈性，并根據(jù)地形，難以控制汽車。輸入減震器和緩沖器，一個(gè)裝置，通過控制作為一個(gè)過程稱為抑制有害彈簧的方案。減震器慢下來，減少轉(zhuǎn)化為熱能，可以通過液壓油消退了懸架運(yùn)動動能的振動運(yùn)動的幅度。要理解這是如何工作，最好找一個(gè)減震器內(nèi)看到它的結(jié)構(gòu)和功能。一個(gè)減震器基本上是安裝在車輪架和車輪之間的油泵。上部安裝的沖擊連接到幀(即彈簧的重量) ，而較低的安裝連接到軸，靠近輪(即沒有裝彈簧的重量) 。在雙管設(shè)計(jì)，對減震器，上部安裝連接到活塞桿，而這又是連接到一個(gè)活塞，從而在一個(gè)充滿液壓油與管坐在最常見的類型之一。內(nèi)管被稱為壓力管，外管，是已知的儲備管。超額準(zhǔn)備金管店液壓油。當(dāng)汽車車輪在路上遇到碰撞，造成對線圈彈簧的傷害，彈簧的能量轉(zhuǎn)移到減震器上安裝通過，穿越活塞桿和活塞進(jìn)入?？诖┛椎幕钊?，使液體泄漏，活塞上下移動，通過在壓力管。由于孔比較小，只有少量的液體承受很大的壓力，經(jīng)過。這將降低活塞，從而減慢彈簧。減震器工作在兩個(gè)周期一壓縮循環(huán)和周期延長。壓縮周期內(nèi)發(fā)生的活塞向下移動，在下面的壓縮腔活塞液壓油。延長周期發(fā)生作為朝著壓力管項(xiàng)部的活塞動作，壓在上面的活塞腔液。一個(gè)典型的汽車或輕型卡車將其壓縮比在其循環(huán)周期延長更多的阻力?？紤]到這一點(diǎn)，壓縮周期控制車輛的簧下重量方案，而延長控制重，彈簧的重量。所有現(xiàn)代的減震器是速度敏感一懸浮移動的速度就越快，越阻力減震器規(guī)定。這使得沖擊，以適應(yīng)道路條件和控制可能出現(xiàn)不需要的方案在行駛的車輛，包括彈跳，搖擺，剎車和加速。6、Struts 和防搖桿另一種常見的阻尼結(jié)構(gòu)是支撐—基本上是一個(gè)減震器安裝在一個(gè)彈簧。它的執(zhí)行兩項(xiàng)工作：他們提供這樣一個(gè)減震器阻尼作用，并為他們提供車輛懸掛的支撐結(jié)構(gòu)。這意味著提供一個(gè)減震器，不支持車重一點(diǎn)—他們只控制在哪是在一輛汽車的重量轉(zhuǎn)移的速度，而不是本身的重量。圖 6-1 共同支撐設(shè)計(jì)由于沖擊有這么多跟一輛汽車的處理，他們可以被認(rèn)為是關(guān)鍵的安全功能。磨損沖擊可以讓過多的車輛從一側(cè)重量轉(zhuǎn)移到一邊，從前到后。這降低了輪胎的抓地力能力的道路，以及處理和制動性能。7、防搖桿防搖桿(也稱為防側(cè)傾桿 )是用于減震器一起給一個(gè)移動的汽車額外的穩(wěn)定。一種防搖桿是一個(gè)金屬棒，跨越整個(gè)橋和有效地加入每一個(gè)暫停方共同努力。當(dāng)在一個(gè)車輪懸架向上和向下移動，防搖桿轉(zhuǎn)讓轉(zhuǎn)移到其他車輪。這將創(chuàng)建一個(gè)更公平的平順性和減少汽車搖擺。特別是，它斗爭的一項(xiàng)關(guān)于暫停其汽車滾裝船，因?yàn)樗慕锹洹；谶@個(gè)原因，今天幾乎所有的汽車都作為標(biāo)準(zhǔn)配置防搖裝置的桿機(jī)構(gòu)，但如果他們沒有，包可以很容易地女裝在任何時(shí)候的桿機(jī)構(gòu)。8、未來的汽車懸架雖然有增強(qiáng)和改善了彈簧和減震器，但汽車懸架的基本設(shè)計(jì)經(jīng)過多年來的沒有一個(gè)顯著的變化。但是這要改變一個(gè)品牌，新的懇掛設(shè)計(jì)構(gòu)思的 Bose 一在相同的 Bose 聲技術(shù)方面的創(chuàng)新而聞名，所有己知的介紹。一些專家甚至說，Bose 是懸浮在汽車懸架以來最大的一個(gè)全獨(dú)立設(shè)計(jì)推出的進(jìn)步。圖 8-1 前懸架模塊它是如何工作的，Bose 在每個(gè)系統(tǒng)使用一個(gè)傳統(tǒng)的沖擊和彈簧安裝輪子代替線性電磁與達(dá)〔LEM的)。放大器提供電力，在這樣一個(gè)權(quán)力與每個(gè)系統(tǒng)的壓縮再生方式的發(fā)動機(jī)。該發(fā)動機(jī)的主要好處是，它們不是由傳統(tǒng)的慣性流體的阻尼器同有的限制。作為一個(gè)結(jié)果，LEM 的可擴(kuò)展和壓縮在一個(gè)更大的速度，幾乎消除了所有客艙震動。該輪的議案能夠如此精細(xì)的控制，該車體保持水平，不論是什么在方向盤的情況。在 LEM 的也可以抵消車身議案，而加速，剎車和轉(zhuǎn)彎，使司機(jī)的控制更大的責(zé)任感。不幸的是，這種模式暫停將無法使用，直到 2009 年，將在一個(gè)或多個(gè)高檔豪華車提供。在此之前，司機(jī)必須依靠可靠的真實(shí)的經(jīng)得起百年考驗(yàn)的懸掛。