【正文】 懸架的歷史 16世紀(jì)的車廂貨。這意味著，雖然基本原理保持不變 ，后獨(dú)立懸可以比前獨(dú)立懸架簡(jiǎn)單 。任何懸架，可用于汽車前橋的便可以用在后橋，以上描述的獨(dú)立懸架的類型能在后橋上 找到。當(dāng)他們分開(kāi)，彈簧體積可以制造的小 得 多，從而降低了懸架占用的空間。 基本設(shè)計(jì)相同 的情況下 ，才能實(shí)現(xiàn)螺旋彈簧取代鋼板。鋼板彈簧的末端與車架相連，減震器 與鋼板彈簧相連。獨(dú)立后 懸架 懸架類型 : 后懸架 如果是一個(gè)后橋與后輪直接相連的汽車，那么它的懸架系統(tǒng)一般來(lái)說(shuō)都比較簡(jiǎn)單 — 基于鋼板彈簧或者是螺旋彈簧之上。 讓我們看看，一個(gè)典型的懸架的工作狀況，從大的底盤環(huán)境 到組成懸架的 每個(gè)零件。 在轉(zhuǎn)彎時(shí)將汽車的重量從高的一邊轉(zhuǎn)移到低的一邊。 減少車身的跳動(dòng)。 使汽車重量從側(cè)面到側(cè)面以及從前到后的轉(zhuǎn)移最小化，因?yàn)檫@種重量的轉(zhuǎn)移減少了輪胎的抓地力。相反的 情況就叫 “ 加速后仰 ” 發(fā)生在加速 ， 汽車重量從前面的輪胎向 后轉(zhuǎn)移。 吸收來(lái)自地面沖撞產(chǎn)生的能量并設(shè)法消耗掉避免車身過(guò)分震動(dòng)。 項(xiàng)目 定義 目標(biāo) 方法 減震 汽車吸收和阻斷來(lái)自地面的震動(dòng)對(duì)乘客和車身部件的沖擊的能力。 這兩個(gè)特點(diǎn)，可以進(jìn)一步被體現(xiàn)在以下三種情況中 — 減 震 能力、抓地力、轉(zhuǎn) 本科生畢業(yè)設(shè)計(jì)（論文） 27 彎性能。大部分汽車工程師考慮動(dòng)態(tài)行駛 汽車從兩個(gè)角度進(jìn)行： 行駛 — 汽車在不平坦的道路上行駛的能力。我們所需要的是一種系統(tǒng)， 能吸收車輪垂直加速能量，使車架和車身在顛簸道路上行駛時(shí)，能不受干擾。在這種情況下，車輪可能會(huì)與道路完全分離。s 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 (., the sprung weight), while the lower mount connects to the axle, near the wheel (., the unsprung weight). In a twintube design, one of the most mon 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. 本科生畢業(yè)設(shè)計(jì)（論文） 25 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 pression cycle and the extension cycle. The pression cycle occurs as the piston moves downward, pressing the hydraulic fluid in the chamber below the piston. The extension cycle occurs as the piston moves toward the top of the pressure tube, pressing the fluid in the chamber above the piston. A typical car or light truck will have more resistance during its extension cycle than its pression cycle. With that in mind, the pression cycle 本科生畢業(yè)設(shè)計(jì)（論文） 26 controls the motion of the vehicle39。re separate, the springs can be much smaller, which reduces the amount of space the suspension takes up. Independent Rear Suspensions If both the front and back suspensions are independent, then all of the wheels are mounted and sprung individually, resulting in what car advertisements tout as fourwheel independent suspension. Any suspension that can be used on the front of the car can be used on the rear, and versions of the front independent systems described in the previous section can be found on the rear axles. Of course, in the rear of the car, the steering rack the assembly that includes the pinion gear wheel and enables the wheels to turn from side to side is absent. This means that rear independent suspensions can be simplified versions of front ones, although the basic principles remain the same. Next, we39。s look at the parts of a typical suspension, working from the bigger picture of the chassis down to the individual ponents that make up the suspension proper. Car Suspension Parts The suspension of a car is actually part of the chassis, which prises all of the important systems located beneath the car39。s center of gravity while cornering, raising one side of the vehicle and lowering the opposite side. Transfer the weight of the car during cornering from the high side of the vehicle to the low side. A car39。s Minimize the transfer of vehicle weight from side to side and front to back, as this transfer of weight reduces the tire39。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. Principle Definition Goal Solution Road Isolation The vehicle39。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 pletely. 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: Ride a car39。 再次衷心感謝我的老師 和同學(xué)們。 在這里感謝我敬愛(ài)的老師和親愛(ài)的同學(xué)們，他們給了我很大的幫助 ，特別 衷心 的感謝我的指導(dǎo)老師 單鵬 教授 ，他經(jīng)驗(yàn)豐富，知識(shí)淵博，他的每句指導(dǎo)都是我終身 受益。這是因?yàn)闇p振器活塞不斷運(yùn)動(dòng)攪動(dòng)著阻尼油而使阻尼油產(chǎn)生氣泡，氣泡會(huì)造成阻尼作用的喪失。高性能減振器通常都具有圈套的筒徑及較大的阻尼。變稀后的阻尼油會(huì)使通過(guò)油閥門的阻力降低而降低了阻尼力，專業(yè)上稱為阻尼衰退。因此．采用傳統(tǒng)的液壓減振器模型為新型車輛設(shè)計(jì)減振器是一個(gè)極為復(fù)雜和耗時(shí)的過(guò)程，不能適應(yīng)現(xiàn)代車輛設(shè)計(jì)的發(fā)展要求 但是目前減振器還有缺陷，例如 減振器的阻尼會(huì)把振動(dòng)沖擊的 能量轉(zhuǎn)換成熱量。其中性能設(shè)計(jì)是通過(guò)減振器內(nèi)各種閥的調(diào)整來(lái)實(shí)現(xiàn)。 計(jì)算按下圖 41 公 式： laPf ?? （ 1） lbpy ?? （ 2） 式中： pf 復(fù)原阻力 （ N） Py 壓縮阻力 （ N） a b 分別為示功圖復(fù) 原部分（ f）和壓縮部分（ y）與基準(zhǔn)線間的最大距離 （ mm） l 試驗(yàn)臺(tái)測(cè)力元件的標(biāo)定常數(shù) （ N/mm） 本科生畢業(yè)設(shè)計(jì)（論文） 17