汽车专业英语 4 Braking system

1、汽车专业英语汽车专业英语 Specialty English for Automobile刘永刚刘永刚E-mail: Tel:hapter 4 Braking systempFeature: a distinctive attribute or aspect of somethingEnergy is required when a vehicle is accelerated from rest to a certain speed. A proportion of that energy is now stored in the vehicle and is ca

2、lled kinetic energy. In order to reduce the speed of the vehicle, the brakes have to convert the kinetic energy to heat energy; the speed of conversion governs the rate at which the vehicle slows down.汽车从原地起步汽车从原地起步( (静止静止) )加速到某一速度需要能量，储存在汽加速到某一速度需要能量，储存在汽车中的那部分能量称为动能。要降低车速车中的那部分能量称为动能。要降低车速, ,制动器必

3、须把动制动器必须把动能转换为热能；转换的速度决定了汽车减速的快慢。能转换为热能；转换的速度决定了汽车减速的快慢。A braking system consists of energy-supplying device, a control device, a transmission device and the brake.供能装置、控制装置、传动装置、制动器供能装置、控制装置、传动装置、制动器The three types of braking systems are in use today: service braking system, parking braking system

4、and additional retarding-braking system. The service braking system and the parking braking system have separate control and transmission devices. The service braking system is normally foot-operated, while the parking braking system is hand-operated.行车制动系、驻车制动系、（缓速式）辅助制动系行车制动系、驻车制动系、（缓速式）辅助制动系Diffe

5、rentiate： recognize or ascertain what makes (someone or something) different Muscular-energy braking system: Energy-assisted braking system power Non-muscular-energy braking system Inertia braking system Gravity braking system Vacuum Hydraulic power人力制动系人力制动系助力制动系助力制动系非人力制动系非人力制动系（动力制动系）（动力制动系）惯性制动系

6、惯性制动系重力制动系重力制动系p Drum / disc brakep Front rear Brake pedal Master cylinder Brake lines/hoses Metering valve Proportioning valve Wheel valve Disc / caliper Drum brakeTwo types of hydraulic brake systems are used. The manual brake system is the simplest. Here, the force of the drivers foot on the peda

7、l applies all the force to the hydraulic system. Another system, the power system, uses parts that assist a driver to the hydraulic system. There is also an antiskid system that prevents the brakes from locking up the wheels and causing skidding.Single-circuit braking systemMulti-circuit braking sys

8、temMechanical HydraulicPneumaticelectrical4.2 Types of brakesDrum brakeThese have two shoes, anchored to a stationary back-plate, which are internally expanded to contact the drum by hydraulic cylinders or a mechanical linkage. Anchor: 锚泊（车船）；固定锚泊（车船）；固定 stall 熄火熄火 抛锚抛锚pLeading shoepTrailing shoeDif

9、ferent drum brake designs result from considerations with regard to application, support and adjustment of the brake shoes. Brakes are assessed in terms of the brake factor C* which expresses the ratio of longitudinal force to tensioning force at the brake shoe. The brake factor takes into considera

10、tion the effect of the coefficient of friction and the internal transmission ratio of the brake.Simplex drum brakes：单一的：单一的 Duo-duplex drum brakes: 双双 双重双重Duo-servo drum brakes： 伺副伺副 増増力力In case of hydraulic braking force actuation, the brakes are applied by means of floating pressure pistons whose

11、travel is not fixed, and which develop tensioning forces which are equal in both directions. One of the two shoes is the leading shoe, i.e. the frictional forces between the brake lining and the brake drum act to support the application force, whereas the frictional forces in the case of the trailin

12、g shoe act to oppose the tensioning force.In the case of the simplex brake, C*(brake factor) is the sum of the values for the individual shoes, and is 2.0（referred to a specific coefficient of friction) A disadvantage of this design is the great difference in the braking effect between the two brake

13、 shoes, and the resulting greatly increased wear on the leading shoe. For this reason, the trailing shoe is often equipped with a much thinner lining than the leading shoe.就领从蹄而言， C*(制动因数)表示各蹄的总和，且.(特指某一摩擦系数）这种设计的缺点是两个制动蹄的制动效果差别很大，结果大大增加了领蹄上的摩擦因此，从蹄的摩擦衬片比领蹄薄Simplex drum brake 领从蹄式制动器领从蹄式制动器S-cam sim

14、plex drum brake 凸轮式凸轮式Advantages: uniform lining wear on leading and trailing shoes as a result of fixed application, and resulting long lining life. This type of drum brake has an application mechanism which is simpler, more reliable and insensitive to temperature. It comprises diaphragm cylinder,

15、automatic slack adjuster, brake shaft and S-cam.Medium and heavy-duty truckThis type of drum brake is characterized by floating application and the corresponding necessary sliding shoe support. An advantage of this type of brake is the nearly equal brake lining wear on both shoes and the higher inte

16、rnal transmission ratio in comparison to simplex brakes.With two leading shoes, brake factors of C* 3.0 are achieved, however, these figures cannot be held constant throughout a long period of braking due to the susceptibility to fading of this type of brake. 制动钳体制动钳体calipercaliper活活 塞塞pistonpiston制

17、动块制动块Friction padFriction pad制动盘制动盘discdiscDisc brake with fixed caliper4.2.2 Disc brakeExposed to the air, disc brakes radiate the heat to the air better than drum brakes. This means that the brake can be operated continuously for a longer period, i.e. they have a greater resistance to fade (fall-o

18、ff in brake efficiency due to heat).由于暴露于空气中，盘式制动器的散热效果比鼓式由于暴露于空气中，盘式制动器的散热效果比鼓式好。这意味着盘式制动器能持续使用更长的时间，好。这意味着盘式制动器能持续使用更长的时间，也就是说其抗热衰退性（因受热导致制动效能下降）也就是说其抗热衰退性（因受热导致制动效能下降）要好得多。要好得多。在许多乘用车上使用的盘式制动器逐渐开始应用在商用在许多乘用车上使用的盘式制动器逐渐开始应用在商用车上。除快速客车外车上。除快速客车外, , 盘式制动器在商用车的使用基本盘式制动器在商用车的使用基本限制在的前桥制动系限制在的前桥制动系, ,

19、且整车重量不超过且整车重量不超过7.57.5吨，这种吨，这种商用车的驱动方式与乘用车相似。商用车的驱动方式与乘用车相似。Disc brakes as used in most passenger cars are slowly beginning to be used in commercial vehicles as well. Aside from their use in fast coaches, current use of disc brakes in commercial vehicles is primarily limited to front-axle brakes for

20、 commercial vehicles up to a weight of approx. 7.5 t which are driven in a manner similar to passenger cars. 4.4 Antilock braking system for passengersAn anti-lock braking system, or ABS (from the German, Antiblockiersystem) is a safety system which prevents the wheels on a motor vehicle from lockin

21、g while braking.A rotating road wheel allows the driver to maintain steering control under heavy braking by preventing a skid. While ABS offers improved vehicle control in some circumstances, it can also present disadvantages including increased braking distance on slippery surfaces such as ice, pac

22、ked snow, gravel, steel plates and bridges, or anything other than dry pavement. ABS has also been demonstrated to create a false sense of security in drivers, who may drive more aggressively as a result.Since initial widespread use in production cars, anti-lock braking systems have evolved considerably. Recent versions not only prevent wheel lock under braking, but also electronically control the fr