毕业设计翻译英文素材(8)

材料一:

Suspension

When 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 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.

The 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.

1.Suspension Principle

If a road were perfectly flat, with no irregularities, suspensions wouldn't be necessary. But roads are far from flat, Even freshly raved highways have subtle imperfections that can interact with the wheels of a car. A bump in the road causes the wheel to move up and down perpendicular to the road surface.

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, 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 system is suspension system.

2. Suspension Types

Suspension systems can be broadly classified into two subgroups-dependent and independent. These terms refer to the ability of opposite wheels to move independently of each other.

A dependent suspension normally has a beam or driven axle that holds wheels parallel to each other and perpendicular to the axle. When the camber of one wheel changes,the camber of the opposite wheel changes in the same way.

An independent suspension allows wheels to rise and fall on their own without affecting the opposite wheel. Suspensions with other devices, such as anti-roll bars that link the wheels in some way are still classed as independent.

A third tpye is a semi-dependent suspension In this case , the motion of one wheel does affect the position of the other but they are not rigidly attached to each other. A twist-beam rear suspension is such a system.

3. Car Suspension Parts

There are three fundamental components of any suspension springs, dampers and anti-sway bars.

1) Springs

Today's springing systems are based on one of four basic designs:

? Coil springs-This is the most common type of spring, as shown in Fig.8-1, 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.

? Leaf springs -This type of spring consists of several layers of metal (called "leaves")，as shown in Fig.8-2. 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.

? Torsion bars -Torsion bars use the twisting properties of a steel bar to provide coil-spring-like performance, as shown in Fig.8-3 .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 hits a acts like a lever that moves perpendicular to the torsion bar. When the wheel hit a bump, vertical motion is transferred to the wishbone and then, through the action, to the torsion bar. The torsion bar then twists along its axis to provide the spring force.

? Air springs - Air springs, as shown in Fig.8-4, which consist of a cylindrical chamber of air positioned between the wheel and the car's 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一i.e.，between the wheels and the Frame-engineers often find it convenient to talk about the sprung mass and the un sprung mass.

2) Dampers :Shock Absorbers

Unless 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.

Enter the shock absorber, as shown in Fig.8-5, 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.

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).

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.

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 co mpression cycle controls the motion of the vehicle's unsprung weight while extension controls the heavier, sprung weight.

All modern shock absorbers are velocity - sensitive一the faster the suspension moves, the more resistance the shock一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.

3) Dampers: Struts and Anti-sway Bars

(1) Struts

Another common dampening structure is the 一basically a shock absorbers, 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.

(2) 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, as shown in Fig.8-7, is a metal rod that spans the entire axle and effectively joins each side of the suspension together(Fig.8-6).

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 they are not. kits make it easy to install the bars at any time.

4. Suspension Types: Front

1) Dependent Front Suspensions

Dependent front suspensions, as shown in Fig.8-7，have a rigid front axle that connects the front wheels. basically, this looks like a solid bar under the front of the car, kept in place by leaf springs and shock absorbers.

2)Independent front suspensions

The MacPherson strut is the most widely used front suspension system, especially in cars of European origin.

The MacPherson strut combines a shock absorber and a coil spring into a single unit. This provides a more compact and lighter suspension system that can be used for front-wheel drive vehicles.

The double-wishbone suspension(Fig.8-8), also known as an A-arm suspension, is another common type of front independent suspension.

Double-wishbone. suspensions allow for more control over the camber angle of the wheel They also help minimize roll or sway and provide for a more consistent steering feel.

5.Suspension Types: Rear

1) Dependent Rear Suspensions

If a solid axle connects the rear wheels of a car, then the suspension is usually quite simple-based either on a leaf spring or a coil spring. In the former design, the leafsprings clamp directly to the drive axle. The ends of the leaf springs attach directly to the frame, and the shock absorber is attached at the clamp that holds the spring to the axle.

The same basic design can be achieved with coil springs replacing the leaves. In this case, the spring and shock absorber can be mounted as a single unit or as separate components. When they're separate, the springs can be much smarter, which reduces the amount of space the suspension takes up.

2) Independent Rear Suspensions

If both the front and back suspensions are independent, then all of the wheels are mounted and sprung individually. 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.

Historical Suspension

Sixteenth-century wagons and carriage tried to solve the problem of "feeling every bump in the road" by slinging the carriage body from leather straps attached to four posts of a chassis that looked like an upturned table. Because the carriage body was suspended from the chassis, the system came to be known as a "suspension'’-a term still used today to describe the entire class of solutions. The slung-body suspension was not a true springing system, but it did enable the body and the wheels of the carriage to move independently

Semi-elliptical spring designs, also known as cart springs, quickly replaced the leather-strap suspension. Popular on wagons, buggies and carriages, the semi-elliptical springs were often used on both the front and rear axles. They did, however, tend to allow forward and backward sway and had a high center of gravity By the time powered car hit the road, other , more efficient springing systems were being developed to smooth out rides for passengers.

Specialized Suspensions: Formula One Racers

The Formula One racing car(Fig.l) represents the pinnacle of automobile innovation and evolution. Lightweight, composite bodies, powerful V10 engines and advanced aerodynamics have led to faster, safer and more reliable cars.

To elevate driver skill as the key differentiating factor in a race, stringent rules and requirements govern Formula One racecar design. For example, the rules regulating suspension design say that all- Formula One racers must be conventionally sprung, but they don't allow computer-controlled, active suspensions. To accommodate this, the cares feature multi-link suspensions, which use a multi-rod mechanism equivalent to a double-wishbone system.

Recall that a double-wishbone design uses two wishbone-shaped control arms to guide each wheel's up-and-down motion. Each arm has three mounting positions-two at the frame and one at the wheel hub-and each joint is hinged to guide the wheel's motion. In all cars, the primary benefit of a double-wishbone suspension is control. The geometry of the arms and elasticity of the joints give engineers ultimate control over the angle of the wheel and other vehicle dynamics, such as lift, squat and

dive. Unlike road cars, however, the shock absorbers and coil springs of a Formula One racecar don't mount directly to the control arms. Instead, they are oriented along the length of the car and are controlled remotely through a series of pushrods and bell cranks. In such an arrangement, the pushrods and bell cranks translate the up-and-down motions of the wheel to the back-and-forth movement of the spring-and-damper apparatus.

Specialized Suspensions:Hot Rods

The classic American hot rod era lasted from 1945 to about 1965.Like Baja Bugs, the classic hot rods required significant modification by their owners. Unlike Bugs, however, which are built on V olkswagen chassis, hot rods were built on a variety of old, often historical, car models:Cars manufactured before 1945 were considered ideal fodder for hot rod transformations because their bodies and frames were often in good shape, while their engines and transmissions needed to be replaced completely. For hot rod enthusiasts, this was exactly what they wanted, for it allowed them to install more reliable and powerful engines, such as the flat-head Ford V8 or the Chevrolet V8.

One popular hot rod was known as the T bucket(Fig.2) because it was based on the Ford Model To The stock Ford suspension: on the front of the Model T consisted of a solid I -beam front axle (a dependent suspension), a U-shaped buggy spring (leaf spring) and a wishbone-shaped radius rod with a ball at the rear end that pivoted in a cup attached to the transmission. Ford's engineers built the Model: T to ride high with a large amount of suspension movement, an ideal design for the rough; primitive roads of the 1930s. But after World War II, hot rodders began experimenting with larger Cadillac or Lincoln engines, which meant that the wishbone-shaped radius rod was no longer applicable. Instead,they removed the center ball and bolted the ends of the wishbone to the frame rails. This "split wishbone"design lowered the front axle about 1 inch(2.5 cm) and improved handling.

Lowering the axle more than an inch reauired a brand-new design, which was supplied by a company known as Bell Auto. Throughout the 1940s and 1950s, Bell auto offered dropped tube axles that lowered the car a full 5 inches (13 cm). Tube axles were built from smooth, steel tubing and balanced strength with superb aerodynamics.Thesteel surface also accepted chrome plating better than the forged I-beam axles, so hot rodders often preferred them for their aesthetic qualities,as well.

Some hot rod enthusiasts, however, argued that the tube axle's rigidity and

inability to flex compromised how it handled the stresses of driving. To accommodate this,hotrodders introduced the four-bar suspension, using two mounting points on the axle and two on the frame. At each mounting point, aircraft-style rod ends provided plenty of movement at all angles.

Specialized Suspensions: The Baja Bug

What follows is a brief overview of how suspensions are designed for three types of specialty cars-Baja Bugs(Fig.3), Formula One racers and American-style hot rods.

The V olkswagen Beetle, or Bug, was destined to become a favorite among off-road enthusiasts.With a low center of gravity and engine placement over the rear axle, the two-wheel-drive Bug handles off-road conditions as well as some four-wheel-drive vehicles. Of course, the VW Bug isn't ready for off-road conditions with its factory equipment. Most Bugs require some moditications, or conversions, to get them ready for racing in harsh conditions like the deserts of Baja California.

One of the most important modifications takes place in the suspension, The torsion- bar suspension, standard equipment on the front and back of most Bugs between 1936 and 1977 ,can be raised to make room for heavy-duty, off-road wheels and tires. Longer shock absorbers replace the standard .shocks to lift the body higher and to provide for maximum wheel travel. In some cases , Baja Bug converters remove the torsion bars entirely and replace them with multiple coil-over systems, an attermaret item that combines both the spring and shock absorber in one adjustable unit. The result of these modifications is a vehicle that allows the wheels to travel vertically 20 inches (50 cm) or more at each end. Such a car can easily navigate rough terrain and often appears to "skip" over desert washboard like a stone over water.

材料二:

Automotive Marketing

First, the auto parts network management concept

American auto parts of automobile fittings dealer Raymond is located in a suburban Atlanta, American and other accessories, this shop to shop and its characteristics, but is online transactions, and car accessories sales related services are

available on the Internet. This distribution store of salespeople have extensive network of knowledge, they patiently helped no online trading experience of customer finish on the Internet. If the customer need, they also can be free of imparting knowledge of online transactions. In order to reflect the rapid and convenient online sales, they provide 24-hour services, if the customer questions, they always strive to reply in 15 minutes. The customer need, sitting at home before entering the store sells computer, then the website can complete all want to do, watch shop fittings, download the pictures, auto prices, orders, etc. Then, you can sit at home or in his own maintenance shop of door-to-door salesman received by car accessories.

Online transaction does have many advantages. To save time, this is obvious. In this way, said dealers trade become a way to attract customers, people gradually accept it and approved. At the same time, the online trading reduced many expenses, including the staff, management, marketing, etc, and save the cost of expenses on auto parts price on the customer benefit.

This is the foreign auto accessories sales of a networked management. This through the Internet and e-commerce fulfillment of our country, and online business, the auto parts marketing MVP has important significance. From the current situation of auto parts, auto sales network throughout the circulation of construction is not perfect, or in an internal network condition. The network Settings are mostly for enterprise internal coordination and daily management, instead of e-commerce.

China's online accessories sales prospects from abroad, also can be the development of auto parts online sales of enlightenment. In the foreign auto accessories sales, how to do? zero kilometers sales How to provide the most satisfactory service to customers? With the Internet, these two problems can greatly alleviate. Now, especially developed countries around the world through the Internet to buy auto accessories are expanding quickly.

Second, the auto parts network management advantages

Online purchase of auto parts for car dealers and customers, whether for auto parts manufacturing enterprise, it is a good thing. First, for auto parts manufacturing enterprise, the Internet can more easily collect customers to buy auto parts in the

process of the various issues, and timely information feedback to the auto parts manufacturing enterprises. According to the above analysis, the enterprise can produce customer purchase intention, thus producing according with market demand as the auto parts. This saves time and cost, and snatch market opportunities. Secondly, the use of Internet information and convenient services, manufacturing enterprises can promptly informed accessories vendors inventory and sales, thereby adjusting their production and auto parts allocation plan. Auto accessories vendors reduce inventory, accelerate the cash flow, obtained satisfactory returns. For users, they can through the Internet, like "menu" optional choose oneself need auto parts.

The market information for auto parts manufacturing enterprise and the seller is important, and can be easily obtained through the Internet. Internet auto parts vendors can provide customers to production enterprise of real-time field information. The demand of information can help to reduce automobile accessories sales production enterprise charges, which usually cost will account for auto parts price of around 15% final sales. If the promotion costs, the cost is higher proportion. In fact, the Internet can also play a role of advertising.

Before that, the sellers of auto parts distribution has always sold in part, and another part of the poor. Money is part of the occupied fee is caused to sell the car accessories. Through the Internet, the production enterprises and vendors can be avoided in production and sales market sales bad auto parts. With the advent of the Internet and convenient service, not only saves time and cost, and more importantly, the Internet can cause a concept of change, auto parts manufacturing enterprise, distributors and customers to be stuck nearlier more.

Third, China's automobile fittings network management development trend China's auto accessories network management and e-commerce, has started to present development trend. Many of the current domestic large and medium-sized car repair enterprises established computer management system, realized the internal network. This covers the entire network maintenance services. To receive from business, dispatching material inspection. Computerized control can be made to understand the undertakings in real-time monitoring, which can form, and greatly improve the

efficiency of the staff, more important is to replace manual accounting and management, strengthen accessories.

Meanwhile, some large scale, the current operating performance good car accessories dealers also introduced a computerized management. Because of automotive products, so use variety of such management software, the personnel must be higher requirements after a period of training to mount guard. Such auto parts management network covers the whole process of operation. From the incoming, retail and wholesale price is determined according to the models, and such Numbers classified management, finally to do account settlement and delivery, and XiaoZhang. Chain-like management make better dealer has put the network management of the whole FenXiaoDian to it, formed a certain scale of network connection. Many automobile fittings all dealers from network management gained good returns. The most prominent feature is reflected in the commodity, through the network management allocations, can reach twice the result with half the effort.

In addition, in recent years the old car accessories circulation system gr adually broken, auto parts market, constantly mature vigorous development. Some far-sighted insight, the operator has felt the network era, and start a near the market network. Like changchun automobile fittings, west of Beijing automobile fittings, Shanghai auto parts market such as the city of virtual network construction and the development of the market for 2000. But the reality is that the network is quite childish, but certainly not realize online trading and service.

With the quickening pace of "two", the personage inside course of study to commend "trinity" sales mode in the earth gradually. For example, in the choice of Shanghai general dealers, whether to have "trinity" sales ability to determine the object, such as a "trinity" whole car accessories sales mode is a microcosm of network flow field. Because it includes from truckload sale, spare parts supply and maintenance.

Mention auto parts network management and e-commerce, somebody thinks, car accessories telephone shopping is actually c-commerce, because only communication platform between different, the operation is basically the same. Actually this kind of understanding is not accurate, phone business and e-commerce is more like Cousins, in many ways, phone business congenital

deficiency. First, consumers from the phone in understanding the information is limited, can fully satisfy customer's requirements. Secondly, if advertisers, or printing accessories for customers, due to the directory of accessories sales, cost of printing more and more high, but slow renewal speed. In addition, on the telephone exchanges, due to the environment, voice, speaking, the influence of factors, make telephone service personnel difficulty and error rates increased. Just as phone business, management content in depth and breadth aspect further development will be limited.

Fourth,Auto parts distribution system and network management of construction

Auto parts distribution system and network management of construction is now a successful online trading tangible products such as books, audio and video products, clothing, etc., and auto parts as a certain scientific and technological content, some products are statemandatory standard industrial products, to achieve on-line transactions, compared with other industrial products, have their advantages, sellers and buyers as long as posted on the Internet and input information about auto parts, such as vehicles, cars, parts name, part number, manufacture, price, quantity, etc., you can sell online or purchase.To truly realize the concept of e-commerce online sales, buyers and sellers in addition to solving the "integrity" issues, but also must establish a complete set of efficient logistics distribution system.Speaking before the factors that limit development of electronic commerce, nothing more than a means of payment, security authentication, the real make up, will find car parts logistics and distribution system is the most difficult, the most facile, the most expensive one.Many auto parts e-commerce companies are trying to find the existing physical network, such as postal services, courier and even newspaper delivery company as a delivery system.However, a suitable auto parts distribution and e-commerce system should look like?The conditions of physical network can be transformed into an auto parts distribution system of e-commerce will be the lowest cost?

Five, Auto parts network management is the only way for the development and reform of the road network

The Chinese auto parts sales development should be appropriate for the situation in China, with Chinese characteristics, the way the Internet business. Indeed, the United States, network operators have achieved great success, but we can not ignore this brilliant behind the social basis of the United States strong material foundation. As early

as 100 years ago, the U.S. has established a comprehensive road, rail, postal services, courier delivery system combining; today's society, Americans have been accusto med to "free currency trading." It can be said that today's Internet economy development in the United States should be a very natural result and is more than 200 years the United States as a free market economy based on natural product. Like a child to cl imb from the start with their bare hands, and then learn to walk, over time learned to run naturally. As the development of China, only two aspects of payment and delivery has become a fatal problem "bottleneck." How to combine the development of China's n ational conditions and characteristics of the Internet, be able to realistically do something practical auto parts network operators today is the development of priority. China's auto parts e-commerce and enterprise network operators must follow the joint and it should be a very natural result is more than 200 years the United States as a free market economy based on natural product. Like a child to climb from the start with their bare hands, and then learn to walk, over time learned to run naturally. As the development of China, only two aspects of payment and distribution has become a fatal problem "bottleneck."

How to combine the development of China's national conditions and characteristics of the Internet, Being able to realistically do something practical auto parts network operators today is the development of priority.