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汽车制动系统外文翻译

汽车制动系统外文翻译
汽车制动系统外文翻译

河南理工大学万方科技学院

毕业设计(论文)附录I 中英文文献翻译

姓名:王奎

所在院系:机械与动力工程系

专业班级:机械设计08-3班

学号: 0828070005

指导教师:赵武

原文标题:Automobile Brake System 2012 年 5 月 25 日

Automobile Brake System

The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes.

Two complete independent braking systems are used on the car. They are the service brake and the parking brake.

The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set.

The brake system is composed of the following basic components: the “m aster cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the “slave cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by the slave cylinders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car.

The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder .

Basically, all car brakes are friction brakes. When the driver applies the brake, the control device forces brake shoes, or pads, against the rotating brake drum or disks at

wheel. Friction between the shoes or pads and the drums or disks then slows or stops the wheel so that the car is braked.

In most modern brake systems, there is a fluid-filled cylinder, called master cylinder, which contains two separate sections, there is a piston in each section and both pistons are connected to a brake pedal in the driver’s compartment. When the brake is pushed down, brake fluid is sent from the master cylinder to the wheels.

At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The friction between the stationary shoes, or pads, and the revolving drums or disks slows and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop the car.

The brake fluid reservoir is on top of the master cylinder. Most cars today have a transparent r reservoir so that you can see the level without opening the cover. The brake fluid level will drop slightly as the brake pads wear. This is a normal condition and no cause for concern. If the level drops noticeably over ashort period of time or goes down to about two thirds full, have your brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill it and never leave a cam of brake fluid uncovered. Brake fluid must maintain a very high boiling point. Exposure to air will cause the fluid to absorb moisture which will lower that boiling point.

The brake fluid travels from the master cylinder to the wheels through a series of steel tubes and reinforced rubber hoses. Rubber hoses are only used in places that require flexibility, such as at the front wheels, which move up and down as well as steer. The rest of the system uses non-corrosive seamless steel tubing with special fittings at all attachment points. If a steel line requires a repair, the best procedure is to replace the compete line. If this is not practical, a line can be repaired using special splice fittings that are made for brake system repair. You must never use copper tubing to repair a brake system. They are dangerous and illegal.

Drum brakes, it consists of the brake drum, an expander, pull back springs, a stationary back plate, two shoes with friction linings, and anchor pins. The stationary back plate is secured to the flange of the axle housing or to the steering knuckle. The brake drum is mounted on the wheel hub. There is a clearance between the inner surface of the drum and the shoe lining. To apply brakes, the driver pushes pedal, the expander expands the shoes and presses them to the drum. Friction between the brake drum and the friction linings brakes the wheels and the vehicle stops. To release brakes, the driver release the pedal, the pull back spring retracts the shoes thus permitting free rotation of the wheels.

Disk brakes, it has a metal disk instead of a drum. A flat shoe, or disk-brake pad, is located on each side of the disk. The shoes squeeze the rotatin g disk to stop the car. Fluid from the master cylinder forces the pistons to move in, toward the disk. This action pushes the friction pads tightly against the disk. The friction between the shoes and disk slows and stops it. This provides the braking action. Pistons are made of either plastic or metal. There are three general types of disk brakes. They are the floating-caliper type, the fixed-caliper type, and the sliding-caliper type.

Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper disk brakes have either two or four pistons.

Brakes - what do they do?

Brakes are designed to slow down your vehicle but probably not by the means that you think. The common misconception is that brakes squeeze against a drum or disc, and the pressure of the squeezing action is what slows you down. This in fact is only part of the equation. Brakes are essentially a mechanism to change energy types. When you're travelling at speed, your vehicle has kinetic energy. When you apply the brakes, the pads or shoes that press against the brake drum or rotor convert that energy into thermal energy via friction. The cooling of the brakes dissipates the heat and the vehicle slows down. It's the First Law of Thermodynamics, sometimes known as the law of conservation of energy. This states that energy cannot be created nor

destroyed, it can only be converted from one form to another. In the case of brakes, it is converted from kinetic energy to thermal energy.

Angular force. Because of the configuration of the brake pads and rotor in a disc brake, the location of the point of contact where the friction is generated also provides a mechanical moment to resist the turning motion of the rotor.

Thermodynamics, brake fade and drilled rotors.

If you ride a motorbike or drive a race car, you're probably familiar with the term brake fade, used to describe what happens to brakes when they get too hot. A good example is coming down a mountain pass using your brakes rather than your engine to slow you down. As you start to come down the pass, the brakes on your vehicle heat up, slowing you down. But if you keep using them, the rotors or drums stay hot and get no chance to cool off. At some point they can't absorb any more heat so the brake pads heat up instead. In every brake pad there is the friction material that is held together with some sort of resin and once this starts to get too hot, the resin starts to vapourise, forming a gas. Because the gas can't stay between the pad and the rotor, it forms a thin layer between the two whilst trying to escape. The pads lose contact with the rotor, reducing the amount of friction and voila. Complete brake fade.

The typical remedy for this would be to get the vehicle to a stop and wait for a few minutes. As the brake components cool down, their ability to absorb heat returns and the next time you use the brakes, they seem to work just fine. This type of brake fade

was more common in older vehicles. Newer vehicles tend to have less outgassing from the brake pad compounds but they still suffer brake fade. So why? It's still to do with the pads getting too hot. With newer brake pad compounds, the pads transfer heat into the calipers once the rotors are too hot, and the brake fluid starts to boil forming bubbles in it. Because air is compressible (brake fluid isn't) when you step on the brakes, the air bubbles compress instead of the fluid transferring the motion to the brake calipers. Voila. Modern brake fade.

So how do the engineers design brakes to reduce or eliminate brake fade? For older vehicles, you give that vapourised gas somewhere to go. For newer vehicles, you find some way to cool the rotors off more effectively. Either way you end up with cross-drilled or grooved brake rotors. While grooving the surface may reduce the specific heat capacity of the rotor, its effect is negligible in the grand scheme of things. However, under heavy braking once everything is hot and the resin is vapourising, the grooves give the gas somewhere to go, so the pad can continue to contact the rotor, allowing you to stop.

The whole understanding of the conversion of energy is critical in understanding how and why brakes do what they do, and why they are designed the way they are. If you've ever watched Formula 1 racing, you'll see the front wheels have huge scoops inside the wheel pointing to the front (see the picture above). This is to duct air to the brake components to help them cool off because in F1 racing, the brakes are used viciously every few seconds and spend a lot of their time trying to stay hot. Without some form of cooling assistance, the brakes would be fine for the first few corners but then would fade and become near useless by half way around the track.

Rotor technology.

If a brake rotor was a single cast chunk of steel, it would have terrible heat dissipation properties and leave nowhere for the vapourised gas to go. Because of this, brake rotors are typically modified with all manner of extra design features to help them cool down as quickly as possible as well as dissapate any gas from between the

pads and rotors. The diagram here shows some examples of rotor types with the various modification that can be done to them to help them create more friction, disperse more heat more quickly, and ventilate gas. From left to right.

1: Basic brake rotor. 2: Grooved rotor - the grooves give more bite and thus more friction as they pass between the brake pads They also allow gas to vent from between the pads and the rotor. 3: Grooved, drilled rotor - the drilled holes again give more bite, but also allow air currents (eddies) to blow through the brake disc to assist cooling and ventilating gas. 4: Dual ventilated rotors - same as before but now with two rotors instead of one, and with vanes in between them to generate a vortex which will cool the rotors even further whilst trying to actually 'suck' any gas away from the pads.

An important note about drilled rotors: Drilled rotors are typically only found (and to be used on) race cars. The drilling weakens the rotors and typically results in microfractures to the rotor. On race cars this isn't a problem - the brakes are changed after each race or weekend. But on a road car, this can eventually lead to brake rotor failure - not what you want. I only mention this because of a lot of performance suppliers will supply you with drilled rotors for street cars without mentioning this little fact.

Big rotors.

How does all this apply to bigger brake rotors - a common sports car upgrade? Sports cars and race bikes typically have much bigger discs or rotors than your average family car. A bigger rotor has more material in it so it can absorb more heat. More material also means a larger surface area for the pads to generate friction with,

and better heat dissipation. Larger rotors also put the point of contact with the pads further away from the axle of rotation. This provides a larger mechanical advantage to resist the turning of the rotor itself. To best illustrate how this works, imagine a spinning steel disc on an axle in front of you. If you clamped your thumbs either side of the disc close to the middle, your thumbs would heat up very quickly and you'd need to push pretty hard to generate the friction required to slow the disc down. Now imagine doing the same thing but clamping your thumbs together close to the outer rim of the disc. The disc will stop spinning much more quickly and your thumbs won't get as hot. That, in a nutshell explains the whole principle behind why bigger rotors = better stopping power.

The different types of brake.

All brakes work by friction. Friction causes heat which is part of the kinetic energy conversion process. How they create friction is down to the various designs.

Bicycle wheel brakes

I thought I'd cover these because they're about the most basic type of functioning brake that you can see, watch working, and understand. The construction is very simple and out-in-the-open. A pair of rubber blocks are attached to a pair of calipers which are pivoted on the frame. When you pull the brake cable, the pads are pressed against the side or inner edge of the bicycle wheel rim. The rubber creates friction, which creates heat, which is the transfer of kinetic energy that slows you down. There's only really two types of bicycle brake - those on which each brake shoe shares the same pivot point, and those with two pivot points. If you can look at a bicycle

brake and not understand what's going on, the rest of this page is going to cause you a bit of a headache.

Drum brakes - single leading edge

The next, more complicated type of brake is a drum brake. The concept here is simple. Two semicircular brake shoes sit inside a spinning drum which is attached to the wheel. When you apply the brakes, the shoes are expanded outwards to press against the inside of the drum. This creates friction, which creates heat, which transfers kinetic energy, which slows you down. The example below shows a simple model. The actuator in this case is the blue elliptical object. As that is twisted, it forces against the brake shoes and in turn forces them to expand outwards. The return spring is what pulls the shoes back away from the surface of the brake drum when the brakes are released. See the later section for more information on actuator types.

The "single leading edge" refers to the number of parts of the brake shoe which actually contact the spinning drum. Because the brake shoe pivots at one end, simple geometry means that the entire brake pad cannot contact the brake drum. The leading edge is the term given to the part of the brake pad which does contact the drum, and in the case of a single leading edge system, it's the part of the pad closest to the actuator. This diagram (right) shows what happens as the brakes are applied. The shoes are pressed outwards and the part of the brake pad which first contacts the drum is the leading edge. The action of the drum spinning actually helps to draw the brake pad outwards because of friction, which causes the brakes to "bite". The trailing edge of

the brake shoe makes virtually no contact with the drum at all. This simple geometry explains why it's really difficult to stop a vehicle rolling backwards if it's equipped only with single leading edge drum brakes. As the drum spins backwards, the leading edge of the shoe becomes the trailing edge and thus doesn't bite.

Drum brakes - double leading edge

The drawbacks of the single leading edge style of drum brake can be eliminated by adding a second return spring and turning the pivot point into a second actuator. Now when the brakes are applied, the shoes are pressed outwards at two points. So each brake pad now has one leading and one trailing edge. Because there are two brake shoes, there are two brake pads, which means there are two leading edges. Hence the name double leading edge.

Disc brakes

Some background. Disc brakes were invented in 1902 and patented by Birmingham car maker Frederick William Lanchester. His original design had two discs which pressed against each other to generate friction and slow his car down. It wasn't until 1949 that disc brakes appeared on a production car though. The obscure American car builder Crosley made a vehicle called the Hotshot which used the more familiar brake rotor and calipers that we all know and love today. His original design was a bit crap though - the brakes lasted less than a year each. Finally in 1954 Citro?n launched the way-ahead-of-its-time DS which had the first modern incarnation of disc brakes along with other nifty stuff like self-levelling suspension, semi-automatic

gearbox, active headlights and composite body panels. (all things which were

re-introduced as "new" by car makers in the 90’s).

Disc brakes are an order of magnitude better at stopping vehicles than drum brakes, which is why you'll find disc brakes on the front of almost every car and motorbike built today. Sportier vehicles with higher speeds need better brakes to slow them down, so you'll likely see disc brakes on the rear of those too.

The brake system assemblies are actuated by mechanical, hydraulic or pneumatic devices. The mechanical leverage is used in the parking brakes fitted in all automobile. When the brake pedal is depressed, the rod pushes the piston of brake master cylinder which presses the fluid. The fluid flows through the pipelines to the power brake unit and then to the wheel cylinder. The fluid pressure expands the cylinder pistons thus pressing the shoes to the drum or disk. If the pedal is released, the piston returns to the initialposition, the pull back springs retract the shoes, the fluid is forced back to the master cylinder and braking ceases.

The primary purpose of the parking brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by the driver when a separate parking braking hand lever is set. The hand brake is normally used when the car has already stopped. A lever is pulled and the rear brakes are approached and locked in the “on” position. The car may now be left without fear of its rolling away. When the driver wants to move the car again, he must press a button before the lever can be released. The hand brake must also be able to stop the car in the event of the

foot brake failing. For this reason, it is separate from the foot brake uses cable or rods instead of the hydraulic system.

Anti-lock Brake System

Anti-lock brake systems make braking safer and more convenient, Anti-lock brake systems modulate brake system hydraulic pressure to prevent the brakes from locking and the tires from skidding on slippery pavement or during a panic stop.

Anti-lock brake systems have been used on aircraft for years, and some domestic car were offered with an early form of anti-lock braking in late 1990’s. Recently, several automakers have introduced more sophisticated anti-lock system. Investigations in Europe, where anti-lock brakin g systems have been available for a decade, have led one manufacture to state that the number of traffic accidents could be reduced by seven and a half percent if all cars had anti-lock brakes. So some sources predict that all cars will offer anti-lock brakes to improve the safety of the car.

Anti-lock systems modulate brake application force several times per second to hold the tires at a controlled amount of slip; all systems accomplish this in basically the same way. One or more speed sensors generate alternating current signal whose frequency increases with the wheel rotational speed. An electronic control unit continuously monitors these signals and if the frequency of a signal drops too rapidly indicating that a wheel is about to lock, the control unit instructs a modulating device to reduce hydraulic pressure to the brake at the affected wheel. When sensor signals indicate the wheel is again rotating normally, the control unit allows increased hydraulic pressure to the brake. This release-apply cycle occurs several time per second to “pump” the brakes like a driver might but at a much faster rate.

In addition to their basic operation, anti-lock systems have two other things in common. First, they do not operate until the brakes are applied with enough force to lock or nearly lock a wheel. At all other times, the system stands ready to function but does not interfere with normal braking. Second, if the anti-lock system fail in any way,

the brakes continue to operate without anti-lock capability. A warning light on the instrument panel alerts the driver when a problem exists in the anti-lock system.

The current Bosch component Anti-lock Braking System (ABSⅡ), is a second generation design wildly used by European automakers such as BWM,

Mercedes-Benz and Porsche. ABSⅡ system consists of : four wheel speed sensor, electronic control unit and modulator assembly.

A speed sensor is fitted at each wheel sends signals about wheel rotation to control unit. Each speed sensor consists of a sensor unit and a gear wheel. The front sensor mounts to the steering knuckle and its gear wheel is pressed onto the stub axle that rotates with the wheel. The rear sensor mounts the rear suspension member and its gear wheel is pressed onto the axle. The sensor itself is a winding with a magnetic core. The core creates a magnetic field around the winding, and as the teeth of the gear wheel move through this field, an alternating current is induced in the winding. The control unit monitors the rate o change in this frequency to determine impending brake lockup.

The control unit’s function can be divided into three parts: signal processing, logic and safety circuitry. The signal processing section is the converter that receives the alternating current signals form the speed sensors and converts them into digital form for the logic section. The logic section then analyzes the digitized signals to calculate any brake pressure changes needed. If impending lockup is sensed, the logic section sends commands to the modulator assembly.

Modulator assembly

The hydraulic modulator assembly regulates pressure to the wheel brakes when it receives commands from the control utuit. The modulator assembly can maintain or reduce pressure over the level it receives from the master cylinder, it also can never apply the brakes by itself. The modulator assembly consists of three high-speed electric solenoid valves, two fluid reservoirs and a turn delivery pump equipped with

inlet and outlet check valves. The modulator electrical connector and controlling relays are concealed under a plastic cover of the assembly.

Each front wheel is served by electric solenoid valve modulated independently by the control unit. The rear brakes are served by a single solenoid valve and modulated together using the select-low principle. During anti-braking system operation, the control unit cycles the solenoid valves to either hold or release pressure the brake lines. When pressure is released from the brake lines during anti-braking operation, it is routed to a fluid reservoir. There is one reservoir for the front brake circuit. The reservoirs are low-pressure accumulators that store fluid under slight spring pressure until the return delivery pump can return the fluid through the brake lines to the master cylinder.

汽车制动系统

制动系统是汽车中最重要的系统。如果制动失灵,结果可能是损失惨重的。制动器实际就是能量转换装置,它将汽车的动能(动量)转化成热能(热量)。当驾驶员踩下制动踏板,所产生的制动力是汽车运动时动力的10倍。制动系统能对四个刹车系统中的每个施加数千磅的力。

每辆汽车上使用两个完全独立的制动系统,即行车制动系和驻车制动系。

行车制动起到减速、停车、或保持车辆正常行驶。制动器是由司机用脚踩、松制动器踏板来控制的。驻车制动器的主要作用就是当车内无人的时候,汽车能够保持静止。当独立的驻车制动器—踏板或手杆,被安装时,驻车制动器就会被机械地操作。

制动系统是由下列基本的成分组成:位于发动机罩下方,而且直接地被连接到制动踏板的“制动主缸”把驾驶员脚的机械力转变为液压力。钢制的“制动管路”和有柔性的“制动软管”把制动主缸连接到每个轮子的“制动轮缸”上。制动液, 特别地设计为的是工作在极端的情况,填充在系统中。“制动盘”和“衬块”是被制动轮缸推动接触“圆盘”和“回转体”如此引起缓慢的拖拉运动, (希望)使汽车减慢速度。

典型的制动系统布置有前后盘式,前盘后鼓式,各个车轮上的制动器通过一套管路系统连接到制动主缸上。

基本上讲,所有的汽车制动器都是摩擦制动器。当司机刹车时,控制装置会迫使制动蹄,或制动衬片与车轮处的旋转的制动鼓或制动盘接触。接触后产生的摩擦使车轮转动减慢或停止,这就是汽车的制动。

在最基本的制动系统中,有一个制动主缸,这个主缸内部填充制动液,并包含两个部分,每个部分里都有一个活塞,两个活塞都连接驾驶室里的制动踏板。当制动踏板被踩下时,制动液会从制动主缸流入轮缸。在轮缸中,制动液推动制

动蹄或制动衬片与旋转的制动鼓或制动盘接触。静止的制动蹄或制动衬片与旋转的制动鼓或制动盘之间产生摩擦力使汽车的运动逐渐减缓或停止。

制动液的装置位于主缸的顶部。目前大多数的车都有一个容易看见的装制动液的装置,为的是不用打开盖子就可以看得见制动液的油面。随着制动踏板的运动制动液就会缓慢的下降,正常情况下是这样的。如果制动液在很短的时间内下降得明显或者下降了三分之二,那么就要尽快的检查你的制动系统了。保持制动液装置充满制动液除非你需要维修它,制动液必须保持很高的沸点。位于在空气中的制动液就会吸收空气中的潮气引起制动液低于沸点。

制动液通过一系列的管路从主缸到达各车轮。橡胶软管只用在需要弹力的地方,比如应用在前轮。在车的行进中上下来回运动。系统的其它部分在所有的连接点上都应用了无腐蚀性的无缝钢管。如果钢线需要修理的话,最好的方法就是代替这条线。如果这不符合实际,那么为了制动系统可以用特殊的装置修理它。你不可以用铜管来修理制动系。它们是危险也是不正确的。

鼓式制动器包括制动鼓,一个轮缸,回拉弹簧,一个制动底版,两个带摩擦层的制动蹄。制动底版固定在轮轴外部的法兰或转向节。制动鼓固定在轮毂上。制动鼓的内部表面与制动蹄的内层之间有空隙。要使用制动器时,司机就要踩下踏板,这时轮缸扩大制动片,对其施加压力,是制动蹄触碰制动鼓。制动鼓与摩擦片之间产生的摩擦制动了车轮,从而使汽车停止。要释放制动器时,司机松开踏板,回拉弹簧拉回制动片,这样车轮会自由转动。

盘式制动器包括制动盘而不是鼓,在它的两面上各有一个薄的制动片或叫盘式制动器的制动片。制动片是靠挤住旋转的制动盘来停住汽车。制动主缸里流出的制动液迫使活塞向里部的金属盘移动,这便使摩擦片紧紧地贴住制动盘。这时制动片与制动盘产生的摩擦使汽车减速、停止,出现了制动行为。活塞分金属或塑料。盘式制动器主要有三种,即:浮动卡钳型、固定卡钳型和滑动卡钳型。浮动卡钳型和滑动卡钳型盘式制动器使用单活塞。固定卡钳型盘式制动器既可以使用两个活塞有可以使用四个活塞。

制动器:它们的作用是什么呢?

简单的说:它会使你的汽车慢下来。

复杂的说:制动器被用来让你的车减速,但可能不是你所想的意思。普遍的误解是,制动器挤压制动鼓或制动片,挤压的压力的作用使你的车慢下来。但这只是制动的一部分。制动系统本质上是改变能量的类型。当你在全速行驶时,你的汽车获得动能。当你踩下刹车,垫子或鞋子对制动鼓和转子的作用转化为摩擦热能。刹车的冷却使车的热能消散,减慢车速。这是热力学第一定律,有时被视为能量守恒定律。也是就说:能量不能被创造也不能被消灭,只能由一种形式转换成另一种。制动情况下,它是动能转化为热能。

角向力

因为在盘式制动器的刹车片和转子的位置,摩擦产生的接触点的位置也产生了一个机械的抵御转子的回转运动。

热力学,制动失效,钻孔转子。

如果你骑摩托车或驾驶一辆赛车,你或许熟悉制动失效,描述当制动器太热,他发生了什么。一个很好的例子就是从山上下来使用刹车制动,而不是你的引擎使你减速。当汽车开始滑动下来时,刹车使汽车产生热能,使你减速。但是如果你持续使用他们,转子或鼓留热并没有机会冷却。从某种意义上说他们不能吸收更多的热量,使刹车垫热了起来。在每一个垫子的摩擦材料有某种共同的树脂一旦开始变得太热,该树脂开始蒸发,形成气。由于气体之间不能待在垫层及转子,而是形成薄薄的一层在两个之间准备排走。垫失去与转子的接触,减少摩擦和热量。这是完全的制动失效。

典型的补救办法,将车停了下来,等待几分钟。由于制动部件降温,吸收热量的原因,下一次您使用刹车的能力,似乎会好一点。这种类型的制动失效在旧车辆更常见。新的车辆往往从刹车垫中减少排气,但他们仍有制动失效。为什么呢?它仍然因为刹车垫太热。犹由于新的刹车垫合成,衬垫的热传递到卡钳一旦转子太热了,制动液开始沸腾冒泡。因为空气是可压缩的(制动液不是)当你踩刹车,气泡的压缩代替了流体转移到制动卡钳。这就是现代制动失效。

工程师们是怎样设计减少或消除刹车制动失效的? 年长的车辆,是使气化的气体有地方排掉。新的车辆,找到一些方式来冷却转子更为有效。无论如何你最终获得交叉钻孔或沟槽刹车盘。当槽表面是可以减少比热容量的转子,其效果可以忽略不计的。然而当大力刹车时一旦一切都是热和树脂材料蒸发,槽让气体排去,所以垫可以继续接触转子,让车减速停下来。

整个的理解能量转换的关键是,刹车他们该做什么,以及为什么它们设计成这样。如果你曾看过一级方程式赛车,你就可以看到向前的前轮里面有很大的洞(如上图所示)。这是管道空气刹车部件,以帮助他们冷却下来,因为在F1赛车中,刹车每隔几秒钟频繁使用,花很多时间预留热量。如果没有某种冷却协助,刹车就可能在最开始的几个转角失灵,最后刹车失效赛车在一半路程出局。

转子技术

如果制动转子是一个单一的钢铁铸块,这将有严重的散热性能和气化气无法排去。因此,刹车盘通常使用各种额外的设计特点的方式来改进帮助他们冷却下来,尽快使垫和转子之间的任何气体排走。这里的图表显示了转子类型的各种修改,可以改进帮助他们创造更多的摩擦力,更迅速地驱散更多的热量,通风气体的一些例子。从左至右。1:基本制动转子。2:沟槽转子-沟槽给予更多口,他们之间产生更多的摩擦,还允许气体从垫和转子之间的排走。3:沟槽钻孔转子-再给多一点口,但也让气流(涡旋)通过制动盘协助冷却和通风。4:双通风转子-以前一样,然而现在有了两个转子而不是一个,和他们之间叶片产生涡流将进一步冷却转子同时试图实际上从衬垫中排掉任何气体。

重要的一点:钻孔转子通常只使用于赛车。钻孔使得转子变弱,通常会导致转子产生各类裂缝。在赛车中这不是一个问题——在每场比赛或者每周都会更换刹车盘。但在路上的车,最终会导致刹车转子失灵的,不是你能想象的。我只提这件事,因为有许多供应商将为您提供钻孔转子,没有直接提到这个事实。

大转子

这是如何适用于更大的刹车转子-一种普遍的跑车升级?汽车和自行车运动比赛通常有比一般的家庭汽车更大的盘或转子。一个更大的转子有更多的材料在里面,因此它可以吸收更多的热量。更多的物质也意味着更大的表面积,垫片产生摩擦,和更好的散热。较大的角度也将转子接触垫进一步远离轴旋转。这提供了一个更大的机械优势抵抗旋转的转子本身。这个工作最好的说明,设想一种纺纱钢轴上的阀瓣在你的面前。如果你夹紧你的大拇指任何一方的阀瓣靠近中间,你的大拇指将热得非常快,你会需要推动相当大的摩擦力使阀瓣慢下来。现在想象做同样的事情,但是你的大拇指夹在一起接近外缘的阀瓣。阀瓣将停止旋转得特别快,你的大拇指也不会很热。简单地说解释整个原理就是更大转子=更好的制动原则。

不同类型的制动器

所有制动器都产生摩擦力。摩擦力是热的一部分动能转换过程。他们是如何不同的设计产生了摩擦的。

自行车车轮制动器

我想我讲述这些,因为它们是最基本类型的制动方式,你可以看到,看工作了解。设计非常简单,在外部。一双橡胶块连接到一双卡钳,能在机架上旋转。当你拉刹车线,刹车垫压向一侧或自行车轮辋的内侧边缘。橡胶产生摩擦,产生热量,这是动能转移使车慢下来。自行车制动实际上只有两个类型- 自行车刹车制动蹄上有相同的摩擦点,并有两个摩擦点。如果你可以看了自行车制动,不明白发生了什么事情,本页面的其余部分你理解起来有麻烦了。

鼓式制动器——单前沿

下一个,更加复杂的类型的制动是鼓式制动器。这是简单的概念。两个半圆形的刹车片装在里面连接一个旋转的车轮的鼓。当你踩下刹车,刹车片向外扩大挤压内侧的鼓。这造成了摩擦,产生热量,转移动能,这将使车减速。下面的例

子显示了一个简单的模型。制动器在这种情况下是蓝色椭圆形的对象。因为这是扭曲的,它的力使刹车片迫使他们向外扩张。当松开刹车,回位弹簧从制动鼓的表面拉回刹车片。看到章节后面更多信息。

"单前沿"是指实际接触的旋转鼓轮制动蹄部件的数量。因为制动蹄片在一端,简单的几何意味着整个刹车片无法都接触到制动鼓。单前沿就是部分刹车片的术语,那些接触制动鼓,在单一制动情况下的方法,在最接近制动器的衬垫。此图(右侧)显示当刹车时,会发生什么情况。这刹车片向外压和制动衬垫的最初接触制动鼓的部分刹车片就是前沿。制动鼓旋转实际上有助于制动片向外加压,因为刹车片向口子的摩擦力。后沿的制动蹄片与制动鼓几乎没有接触。这个简单的几何解释了,为什么汽车是很难停止向后滚动,如果它只配单前缘沿鼓式制动器。由于制动鼓向后旋转,前沿的刹车片成为了后沿,因为制动不会咬合。

鼓刹车——双前沿

可以通过添加回位弹簧和旋转第二个制动器中心点来消除鼓式制动器的单个前沿的缺点。踩下刹车时,刹车片在两个点向外压。所以每个刹车片现在有一个前沿的和一个后沿。因为有两个刹车蹄,那里有两个刹车片,这意味着有两个边沿。因此名称双前沿。

盘式制动器一些背景。

盘式制动器在1902 年被发明,伯明翰汽车制造商检基威廉?兰彻斯特的专利。他原先的设计了两个光盘,紧贴彼此产生摩擦来使车减速。直到1949 盘式制动器的量产车上使用。在美国汽车创始人克罗斯利发明了我们目前熟知和喜爱的快车,就是使用了很多类似的盘动制动器和卡钳。他原先的设计虽然有点缺陷-制动器持续不到一年。终于在1954 年雪铁龙推出先进的DS,成就了像自流平悬浮、半自动变速箱、活动前灯和复合车身盘式制动器的第一次现代化身。(在90年代的汽车制造商重新定义了"新"型车的结构构造)。

机械毕业设计英文外文翻译403驱动桥和差速器

附录A 英文文献 Drive axle/differential All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. Powerflow The drive axle must transmit power through a 90°angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels. Fig 1 Drive axle

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On the vehicle sideslip angle estimation through neural networks: Numerical and experimental results. S. Melzi,E. Sabbioni Mechanical Systems and Signal Processing 25 (2011):14~28 电脑估计车辆侧滑角的数值和实验结果 S.梅尔兹,E.赛博毕宁 机械系统和信号处理2011年第25期:14~28

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中英文文献翻译-汽车制动系统

附录 附录A Braking system function is to make the car driving in accordance with the requirements of the pilot required even slow down park; They offend car has in various road conditions (including in the slope stability) in car; Make the downhill cars speed to be stable. For car up the role of brake is only in the car and role with the direction of the car driving direction opposite forces, and the size of these forces are random, do not control, so cars must be installed on a series of special equipment to achieve the function. Automobile brake system is to point to to ensure that the car in technology, improve the safe driving car average speed, etc., and the admiration installed in the car brake special brake institutions. In general automobile brake system including crane brake system and parking brake two sets of independent device. One crane brake device is a driver with feet to manipulate, and it said the foot brake. Parking brake device is a pilot with the hand, so it says of the manipulation of the hand brake. The function of the crane brake system is to make the car slow down or running in the shortest distance parking within. And parking brake function is to make had stopped the car on the road all keep still. But, sometimes, in an emergency, two braking device can be used at the same time and increase the effect of auto brake. Some special purpose of cars and often in the mountains cars, long and frequently brake will lead to crane brake system overheating, so in these cars often add all sorts of different types of auxiliary braking equipment, so as to speed up the hill stability. According to the braking energy situation, brake system can also be divided into human brake system, power brake system, and servo brake system, three. Human brake system to the driver's physical strength as braking energy; Power brake system engine power to the transformation of the air pressure or hydraulic braking energy as; And servo brake system is the most human and engine power as a brake energy. In addition, according to the braking energy transfer mode, brake system and can be divided into mechanical and hydraulic, pneumatic type and assolenoid style wait until a few kinds.

毕业论文外文翻译-浅谈差速器

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驱动桥外文翻译

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汽车保险中英文对照外文翻译文献

汽车保险中英文对照外文翻译文献(文档含英文原文和中文翻译)

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汽车检测与维修专业汽车制动系统毕业论文外文文献翻译及原文

毕业设计(论文)外文文献翻译 文献、资料中文题目:汽车制动系统 文献、资料英文题目: 文献、资料来源: 文献、资料发表(出版)日期: 院(部): 专业:汽车检测与维修 班级: 姓名: 学号: 指导教师: 翻译日期: 2017.02.14

Automobile Brake System The braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes. Two complete independent braking systems are used on the car. They are the service brake and the parking brake. The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set. The brake system is composed of the following basic components: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the “slave cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by the slave cy linders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car. The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder (Figure). Basically, all car brakes are friction brakes. When the driver applies the

汽车变速器设计外文翻译

汽车变速器设计 ----------外文翻译 我们知道,汽车发动机在一定的转速下能够达到最好的状态,此时发出的功率比较大,燃油经济性也比较好。因此,我们希望发动机总是在最好的状态下工作。但是,汽车在使用的时候需要有不同的速度,这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括,就叫做变速变扭,即增速减扭或减速增扭。为什么减速可以增扭,而增速又要减扭呢?设发动机输出的功率不变,功率可以表示为 N = w T,其中w是转动的角速度,T是扭距。当N固定的时候,w与T是成反比的。所以增速必减扭,减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理,分成各个档位对应不同的传动比,以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴,又称三轴式,另外还有倒档轴。三轴式是变速器的主体结构,输入轴的转速也就是发动机的转速,输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比,也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器,它的传动比分别是:1档3.704:1;2档2.202:1;3档1.414:1;4档1:1;5档(超速档)0.802:1。 当汽车启动司机选择1档时,拨叉将1/2档同步器向后接合1档齿轮并将它锁定输出轴上,动力经输入轴、中间轴和输出轴上的1档齿轮,1档齿轮带动输出轴,输出轴将动力传递到传动轴上(红色箭头)。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈,输出轴转1圈。 当汽车增速司机选择2档时,拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上,动力传递路线相似,所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1,输入轴转2.2圈,输出轴转1圈,比1档转速增加,扭矩降低。

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