制动系统外文翻译.docx

附 录1BRAKE SYSTEMThe 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). The brake system is composed of the following basic components: the “master cylinder” 、“brake lines” 、 “brake hoses” 、“slave cylinders” . “brake disk” “filler block” and so on.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 .Stepping on the brake pedal, a plunger is actually been pushing against in the master cylinder which forces hydraulic oil (brake fluid) through a series of tubes and hoses to the braking unit at each wheel. Since hydraulic fluid (or any fluid for that matter) cannot be compressed, pushing fluid through a pipe is just like pushing a steel bar through a pipe. Unlike a steel bar, however, fluid can be directed through many twists and turns on its way to its destination, arriving with the exact same motion and pressure that it started with. It is very important that the fluid is pure liquid and that there are no air bubbles in it. Air can compress, which causes a sponginess to the pedal and severely reduced braking efficiency. If air is suspected, then the system must be bled to remove the air. There are “bleeder screws” at each wheel cylinder and caliper for this purpose.With drum brakes, fluid is forced into the wheel cylinder which pushes the brake shoes out so that the friction linings are pressed against the drum which is attached to the wheel, causing the wheel to stop.On a disk brake, the fluid from the master cylinder is forced into a caliper where it presses against a piston. The piston, in-turn, squeezes two brake pads against the disk(rotor)which is attached to the wheel, forcing it to slow down or stop. This process is similar to a bicycle brake where two rubber pads rub against the wheel rim creating friction.In either case, the friction surfaces of the pads on a disk brake system, or the shoes on a drum brake convert the forward motion of the vehicle into heat. Heat is what causes the friction surfaces (linings) of the pads and shoes to eventually wear out and require replacement.Drum BrakesSo if disk brakes are so great, how come we still have cars with drum brakes? The reason is cost. While all vehicles produced for many years have disk brakes on the front, drum brakes are cheaper to produce for the rear wheels. The main reason is the parking brake system. On drum brakes, adding a parking brake is the simple addition of a lever, while on disk brakes, we need a complete mechanism, in some cases, a complete mechanical drum brake assembly inside the disk brake rotor! Parking brakes must be a separate system that does not use hydraulics. It must be totally mechanical, but more on parking brakes laterWheel CylinderThe wheel cylinder consists of a cylinder that has two pistons, one on each side. Each piston has a rubber seal and a shaft that connects the piston with a brake shoe. When brake pressure is applied, the pistons are forced out pushing the shoes into contact with the drum. Wheel cylinders must be rebuilt or replaced if they show signs of leaking.Brake Shoes Like the disk pads, brake shoes consist of a steel shoe with the friction material or lining riveted or bonded to it. Also like disk pads, the linings eventuallywear out and must be replaced. If the linings are allowed to wear through to the bare metal shoe, they will cause severe damage to the brake drum. Backing PlateThe backing plate is what holds everything together. It attaches to the axle and forms a solid surface for the wheel cylinder, brake shoes and assorted hardware. It rarely causes any problemsReading material：Disk BrakeDisk brakes, like many automotive innovations, were originally developed for auto racing, but are now standard equipment on virtually every car made. On most cars, the front brake are of the disc type, and the rear brakes are of the “drum” type. Drum brakes use two semi-circular shoes to press outward against the inner surfaces of a steel drum. Older cars often had drum brakes on all four wheels, and many new have 4-wheel disc brakes.Though disc brakes rely on the same basic principles to slow a vehicle (friction and heat), their design is far superior to that of drum brakes. Because disc brakes can fling off water more easily than drum brakes, they work much better in wet conditions. This is not to say that water does not affect them, it definitely does. If you splash through a puddle and then try to apply the brakes, your brakes may not work at all for a few seconds！Disc brakes also allow better airflow cooling, which also increases their effectiveness. Some high performance disc brakes have drilled or slotted holes through the face of the rotor, which helps to prevent the pads from “glazing” (becoming hardened due to heat). Disc brakes were introduced as standard equipment on most cars in the early seventies.译 文制动系统制动系统是汽车中主要的系统之一。 如果制动损坏，结果可能是惨重的。制动器是能量转换装置，它将汽车的动能（动量）转化成热能（热量）。制动系统是由下列基本的成分组成:“制动主缸”“制动管路”“制动软管”“制动轮缸” “制动盘”和“衬块”等等。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。踩着制动踏板时，事实上是制动主缸中的活塞通过一连串的管路和软管强制液压油（制动液）推入到每个轮子上。 因为液压油液(或任何的流动性的物质而言)不能够被压缩,推动液体经过一个管路就像推动一个钢筋通过一个管路。然尔，与钢筋不同的是液体可以直接通过许多弯曲的地方并可以任意改变方向，像它开始的那样以相同的精确的压力和运动到达某个地方。非常重要的是，液体是纯粹的液体而且没有空气泡沫在它里面。当空气被压缩，引起制动踏板的迟疑，并减少制动效率。如果怀疑有空气，那么系统就会放出空气，每个车轮上的放气螺钉和卡钳就是这个目的。在盘式制动器中，主缸中的液体被迫压缩到活塞中。活塞作往复运动，挤压这两个制动块和连接着车轮的制动蹄。这个过程类似于自行车的刹车，自行车的两个橡胶板作用在车轮上制造摩擦。鼓式制动器，流体是被迫进入轮缸，推动制动蹄片向外运动，使摩擦衬垫作用于连接车轮的制动鼓。使车轮停止。无论哪一种情况，盘式制动系中的摩擦表面，还是鼓式制动器中的制动鼓都是把车轮的往复运动转变为热能。热能就是使制动衬垫和制动蹄上的摩擦消失并且代替。鼓式制动器如果盘式制动器市场很大，为何我们仍然使用鼓式制动器？原因在于成本。 而所有车辆零件的生产，多年来采用前盘式，后轮生产鼓式是由于它的价格低。主要的原因是停车制动系统。在鼓式制动器上，增加的一个驻车制动是一个很简单手柄，而在盘式制动器上，我们需要一个完整的机制，在某些情况下，一个完整的机械鼓式制动器内也有盘式制动器的配件！驻车制动器必须是一个不使用液压独立的系统。它必须完全机械，但更多的用在停车制动器。轮缸 轮缸里有两个对称布置活塞。每个活塞有一个橡胶密封件，和连接活塞的活塞杆。当制动压力一定时，活塞被迫推动液压与制动蹄接触，从而实现制动。制动瓦 Like the disk pads, brake shoes consist of a steel shoe with the friction material or lining riveted or bonded to it. Also like disk pads, the linings eventually wear out and must be replaced. If the linings are allowed to wear through to the bare metal shoe, they will cause severe damage to the brake drum.像磁盘丝带、制动瓦是由钢制成的摩擦材料或衬内的铆钉组成。像磁盘丝带一样，摩擦衬片也有坏