汽車制動系統(tǒng) 中英合體

1、<p>　　Automobile Brake Syste </p><p>　　Zhang yongxuan </p><p>　　Machinery class 4 </p><p>　　Xiamen,China</p><p>　　The braking system is the most important system

2、in cars. If the brakes fail, the result </p><p>　　can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When

3、stepping on the brakes, the driver commands a stopping force ten times as powerful as the </p><p>　　force that puts the car in motion. The braking system can exert thousands of pounds of </p><p>

4、;　　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. </p><p>　　The service brake acts to slow, stop, or hold

5、 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 br

6、ake is mechanically operated by when a separate parking brake foot pedal or hand lever is set. </p><p>　　The brake system is composed of the following basic components: the “master cylinder” which is located

7、 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 c

8、ylinders” 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 </p><p>　　The typical brake s

9、ystem 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 </p><p>　　wheel to the master cylinder (Figure). </p&

10、gt;<p>　　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 sh

11、oes or pads and the drums or disks then slows or stops the wheel so that the car is braked. </p><p>　　In most modern brake systems (see Figure 15.1), there is a fluid-filled cylinder, called </p><

12、p>　　master cylinder, which contains two separate sections, there is a piston in each section </p><p>　　and both pistons are connected to a brake pedal in the driver’s compartment. When</p><p>

13、;　　the brake is pushed down, brake fluid is sent from the master cylinder to the wheels. </p><p>　　At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The </p><p>　

14、　friction between the stationary shoes, or pads, and the revolving drums or disks slows </p><p>　　and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop </p><p>&

15、lt;b>　　the car. </b></p><p>　　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

16、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

17、brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill it</p><p>　　The brake fluid travels from the master cylinder to the wheels through a series of st

18、eel 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 seamle

19、ss steel tubing with special fittings at all attachment points. If a steel line requires a repair, the best procedure is to </p><p>　　replace the compete line. If this is not practical, a line can be repaire

20、d 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. </p><p>　　Drum brakes, it consists of the bra

21、ke 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 b

22、rake 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

23、. Friction between the br</p><p>　　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 ca

24、r. </p><p>　　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 st

25、ops 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 typ

26、e. Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper</p><p>　　brakes have either two or four pistons. </p><p>　　The brake system assemblies are actuated by mech

27、anical, hydraulic or pneumatic </p><p>　　devices. The mechanical leverage is used in the parking brakes fitted in all automobile. </p><p>　　When the brake pedal is depressed, the rod pushes the

28、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 sho

29、es 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. </p><p&

30、gt;　　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

31、 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 wa

32、nts to move the car again, he must press a button before the leve</p><p>　　A speed sensor is fitted at each wheel sends signals about wheel rotation to control </p><p>　　unit. Each speed sensor

33、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

34、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 alter

35、nating current is induced in the win</p><p>　　The control unit monitors the rate o change in this frequency to determine impending brake lockup. </p><p>　　The control unit’s function can be divi

36、ded 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

37、 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. Mod

38、ulator assembly The h</p><p>　　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 </p>

39、;<p>　　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

40、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 pres

41、sure until the return delivery pump can return the fluid through the brake</p><p>　　REFERENCES</p><p>　　[1] Wang Wangyu car design. Machinery Industry </p><p>　　Press,2007 </p>

42、;<p>　　[2] Yu Zhisheng. Theory of automobile. Machinery Industry </p><p>　　Press,2006 Chen Jiarui automobile structure </p><p>　　[3]. China Communications Press,2006 </p><p>

43、　　[4] L. Rudolf. Analysis and design of automotive brake </p><p>　　systems. Machinery Industry Press,1985 </p><p>　　[5]" Automotive Engineering Handbook" Automotive </p><p&g

44、t;　　Engineering Handbook Editorial Committee. China </p><p>　　Communications Press,2001Liu Weixin </p><p>　　[6]. Automotive braking system structure analysis and </p><p>　　design ca

45、lculation. Tsinghua University press,2004 </p><p><b>　　汽車制動系統(tǒng)</b></p><p>　　制動系統(tǒng)是汽車中最重要的系統(tǒng)。如果制動失靈，結(jié)果可能是損失慘重的。制動器實際就是能量轉(zhuǎn)換裝置，將動能轉(zhuǎn)化為熱能。當駕駛員踩下制動踏板，所產(chǎn)生的制動力是汽車運動時動力的10倍。制動系統(tǒng)能對四個剎車系統(tǒng)中的每個施加數(shù)千

46、磅的力。每輛汽車上使用兩個完全獨立的制動系統(tǒng)，即行車制動器和駐車制動器。行車制動器起到減速、停車、或保持車輛正常行駛。制動器是由司機用腳踩松 制動器踏板來控制的。駐車制動器的主要作用就是當車內(nèi)無人的時候，汽車能夠保持靜止。當獨立的駐車制動器—踏板或手桿，被安裝時，駐車制動器就會被機械地操作。制動系統(tǒng)是由下列基本的成分組成位于發(fā)動機罩下方，而且直接地被連接到制動踏板的“制動主缸”把駕駛員腳的機械力轉(zhuǎn)變?yōu)橐簤毫Αｄ撝频摹爸苿庸苈贰焙陀腥嵝缘?/p>

47、“制動軟管”把制動主缸連接到每個輪子的“制動輪缸”上。制動液特別地設計為的是工作在極端的情況，填充在系統(tǒng)中。“制動盤”和“襯塊”是被制動輪缸推動接觸“圓盤”和“回轉(zhuǎn)體”如此引起緩慢的拖拉運動, (希望)使汽車減慢速度。典型的制動系統(tǒng)布置有前后盤式，前盤后鼓式，各個車輪上的制動器通過一套管路系統(tǒng)連接到制動主缸上?；旧现v，所有的汽車制動器都是摩擦</p><p><b>　　調(diào)節(jié)裝置</b>&

48、lt;/p><p>　　當接受到電子控制裝置的指令后，液壓執(zhí)行裝置會調(diào)節(jié)制動輪缸的液壓的大小。</p><p>　　調(diào)節(jié)裝置能保持或減小來自制動主缸的液壓，而裝置本身是不能啟用制動器的。</p><p>　　這種裝置有三個高速率的電磁閥，兩個油液存儲器和一個帶有內(nèi)外檢測閥的傳動</p><p>　　泵。調(diào)節(jié)裝置中的電子連接器隱藏在塑料蓋下。每個電