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1、汽车专业英语Specialty English for AutomobileChapter 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 called kinetic energy. In order to redu
2、ce 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(静止)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,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。A braking system consists of energy-supplying device, a co
3、ntrol device, a transmission device and the brake.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 and additional retarding-braking system. The service braking system and the parking braking system have separate control and transmi
4、ssion 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Differentiate： recognize or ascertain what makes (someone or something) different Muscular-energy braking system: Energy-assisted braking system power Non-musc
5、ular-energy braking system Inertia braking system Gravity braking system Vacuum Hydraulic power人力制动系 助力制动系 非人力制动系 （动力制动系） 惯性制动系 重力制动系p Drum / disc brake p Front rearBrake pedal Master cylinder Brake lines/hoses Metering valve Proportioning valve Wheel valve Disc / caliper Drum brakeTwo types of hydr
6、aulic brake systems are used. The manual brake system is the simplest. Here, the force of the drivers foot on the pedal 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 prev
7、ents the brakes from locking up the wheels and causing skidding. Single-circuit braking system Multi-circuit braking system Mechanical Hydraulic Pneumatic electrical4.2 Types of brakesDrum brake These have two shoes, anchored to a stationary back-plate, which are internally expanded to contact the d
8、rum by hydraulic cylinders or a mechanical linkage. Anchor: 锚泊（车船）；固定 stall 熄火 抛锚pLeading shoe pTrailing shoeDifferent 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 expres
9、ses the ratio of longitudinal force to tensioning force at the brake shoe. The brake factor takes into consideration the effect of the coefficient of friction and the internal transmission ratio of the brake.制动器效能因数 ：在制动鼓或制动盘的作用半径只上所得 到的摩擦力(Mp/R)与输入力Fo之比Simplex drum brakes：单一的 Duo-duplex drum brakes
10、: 双 双重 Duo-servo drum brakes： 伺副 増力In case of hydraulic braking force actuation, the brakes are applied by means of floating pressure pistons whose 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 friction
11、al forces between the brake lining and the brake drum act to support the application force, whereas the frictional forces in the case of the trailing 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
12、.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 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 t
13、han 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S-cam simplex drum brake 凸轮式 Advantages: uniform lining wear on leading and trailing shoes as a result of fixed application, and resulting long lining life. This ty
14、pe of drum brake has an application mechanism which is simpler, more reliable and insensitive to temperature. It comprises diaphragm cylinder, automatic slack adjuster, brake shaft and S-cam.Medium and heavy-duty truck This type of drum brake is characterized by floating application and the correspo
15、nding necessary sliding shoe support. An advantage of this type of brake is the nearly equal brake lining wear on both shoes and the higher internal 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
16、 constant throughout a long period of braking due to the susceptibility to fading of this typeof brake.制动钳体 caliper活 塞 piston制动块 Friction pad制动盘 discDisc 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
