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  • 677 汽车液压制动驱动机构的设计
    • 说明书.doc
    • 河北科技师范学院.doc
    • 毕业论文开题报告.doc
    • 综述排版.doc
    • Doc1.doc
    • The Brake System.doc
    • 2主缸缸体.dwg
    • 2二缸活塞.dwg
    • 2制动轮缸.dwg
    • 2端盖.dwg
    • 2缸体.dwg
    • 3一缸活塞.dwg
    • 3后轮轮缸.dwg
    • 3法兰盘.dwg
    • 外文翻译封皮.doc
    • 总封皮.doc
    • 总结封皮.doc
    • 文献综述封皮.doc
    • 装配图.dwg
    • 计划书封皮.doc
    • 设计说明书封皮.doc
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zs677 汽车 液压 制动 驱动 机构 设计
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制动系统 在您的汽车里,制动系统是最重要的系统。如果您的制动器失灵,那么后果是灾难 性的。制动器实际上是能量转换设备,可以将汽车的动能转化为热能。当你踩下制 动器,你便拥有一个比起动你的汽车是强十倍的制动力。制动系统对每个制动件施 加的达数以万计磅的压力。在现代的汽车制动系统中,制动主缸由发动机供给能量。 所有更新型的汽车都有双回路制动系统,和每个轮的从动制动系统。那样的情况下, 如果一个系统失败,另一个将会提供合理充足的制动力,像这样的安全,可靠的制 动系统,使得现代汽车制动系统变得更加复杂,但是比早期的制动系统更加安全了。 制动系统由以下基本元件组成:位于保护罩下的制动主缸,他直接与制动踏板相 连,将脚踏力转化为液体压力。将制动主缸和位于每个车轮的轮缸连接到一起的刚 性油杆和制动软管,和经过特殊处理用以这种特殊环境下的制动油液。制动液和制 动钳,它们由轮缸直接拉紧制动鼓和制动盘从而产生阻力,以降低车速。 今年来,制动器在设计上有了很大的变化。盘式制动器,近些年来多用与前轮制 动,正在快速地替代了用于汽车后轮的鼓式制动器。这大体由于它的更为简单的设 计、更轻的重量和更好的制动性能。盘式制动器相对于鼓式最大的优点是能更有效 的防止制动效能衰退。效能衰退是一种长期在刹车引起的高温等恶劣环境下工作而 引起的临时状况,它通常发生在当制动钳和制动蹄由于高温、高压等环境下应用而 变的光滑。相对于鼓式制动器,盘式可以更好得实现空气冷却,而鼓式不能进行不 断的冷却,因为不断地冷却会导致浸水过多。而盘式浸水后会很快恢复正常,因此 也可以进行多次水冷。 “助力器”应用在动力制动系统,用发动机的能量来对制动主缸施加压力。 “防抱 死系统” ,最初应用在航空制动系统,是用计算机控制着阀体来对每个制动轮缸增减 压力。如果有一轮抱死,汽车将失去转向能力。有了 ABS 防抱死系统,不论制动踏 板的力有多大,每个轮都不会抱死,这样将会防止滑动(提高驾驶员在紧急刹车时 的操纵稳定性) 。 同这些先进的系统原理一样的是,在那些马拉车和儿童车的年代,将车辆的动能 转化为热能这个基本过程。为了使马车停止,驾车者应拉动摩擦车轮的拉杆。但是 今天,由于电动机车蓄能制动器的发展,回收这种浪费的能量的新方式正在被开发。 在这类电力车中,当踩下制动器,机车将进入到“发电模式” ,并将汽车的动能以化 学能的方式存储在电池组内,等到绿灯亮了都可以再次使用。 盘式制动器 盘式制动器就是用夹紧力使转动盘和安装在悬架上的制动钳内的垫片压向转动盘, 从而使车速减低。盘式制动器的制动原理同自行车刹车的原理相似,夹紧制动钳, 使垫片夹紧车轮,从而使自行车减速。盘式制动器提供更高的刹车性能、更加简单 的设计、更轻的重量和较鼓式制动器性能更好的抗水性能。 盘式制动器,跟汽车的其他创新一样,最初是为了跑车开发的,但是现在成了每 辆汽车的标准零件。大多数汽车上,前轮为盘式制动,后轮是鼓式制动。鼓式制动 用两个半圆形的制动蹄压在制动鼓的内圆面上制动。更老式的汽车通常四个轮全为 鼓式制动,而现代的许多汽车都是盘式制动。 由于盘式制动器较鼓式制动器排水教容易,因此在较湿的情况下可以很好的工作, 但着并不是说水对它没有影响,确切说有影响。如果汽车驶过一水坑,然后你去使 用制动器,在几秒钟内,你的制动器将不能工作。盘式制动器可以更好的进行气流 冷却,这将增加它们的有效时间。一些高性能的盘式制动器的转向盘钻有小孔或开 槽,这样可以防止垫片老化(由于高温而变硬化) 。早在 70 年代,盘式制动器已作 为汽车上的标准零件。 制动鼓 制动鼓是一个很重的平头柱体,他被夹在轮缘和轮毂之间,鼓的内表面装有制动 蹄衬片,一旦开始制动,制动蹄承受促动力压紧制动鼓的内圆面而减缓车轮的旋转。 制动鼓外表面通常覆盖着散热片,以更好的冷却。但它们的内部却得不到冷却,因 为一旦水进入通风管道的冷却孔,会使制动性能大大的下降。 在大多数老式的汽车上都可以见到制动鼓,但是它们正在被后轮盘式制动器快速 的替代。在 70 年代前期,大多数汽车采用四个轮全是鼓式制动这种典型的装备, 制动钳 制动钳象 C 钳子一样将摩擦块压紧转动盘,它跨立于转向盘上,并包含辅助缸或 者说是制动轮缸的活塞。制动钳被安装在 各个轮的悬架上,制动钳通常安装在车轴 上,将车轮的扭转力矩传给汽车底盘。 制动油管将制动钳连到有制动主缸控制的制动拉杆上。各个制动钳上都装有放气 阀,将油液中的气泡从系统中排除。 滑动钳盘式制动器是最为普遍的类型,在制动时它的制动钳可以做轻微的轴向滑 动,这是由于制动块的移动(跟制动钳相关) 。一些制动钳包含两个或四个独立的活 塞。这些制动钳必须恰当固定,如,钳体不可以做轴向滑动,而有每个转向盘上的 活塞轴向运动,这种也叫做“双式或双活塞式制动钳” ,在许多高性能的汽车上得到 广泛应用。 制动轮缸 制动轮缸,也叫“辅助”轮缸,在其内有一可滑动活塞,将液体的压力能转化为机 械能。在缸内,作用于活塞上的液体压力使制动蹄或制动片压向制动鼓或制动盘的 表面。每个车轮都有一个轮缸(一些系统甚至有多个) ,鼓式制动器轮缸一般有金属 壳体、活塞复位弹簧、两个活塞、两个橡胶圈或密封垫,和两个用来防止灰尘和水 进入的橡胶垫组成。这种类型的轮缸安装有推杆,通过橡胶垫从活塞的外端伸出, 固定并压住制动蹄。在盘式制动器中,制动轮缸安装在制动钳内。所有的轮缸都装 有放气阀,以便及时清除系统中的气泡。 当踏下制动踏板,拉动主缸活塞压着各轮的制动回路和辅缸中的制动液。油液带 动轮缸的活塞运动,推使制动蹄和制动片压向制动盘或制动鼓。当放开制动力,鼓 式制动器中的复位弹簧将活塞拉回复位。盘式制动器中,制动钳的活塞密封台圈可 使活塞慢慢回位,同时,还可以清洁表面以降低摩擦阻力。 驻车制动 驻车制动(有时也叫做紧急制动)是一个活动缆绳来控制制动器从而使机车制动。 驻车制动激活后轮制动器。通常由一缆绳链接(机械式)代替液压来控制制动蹄或 制动片压向制动盘或制动鼓制动。通过操纵杆或压杆按钮来放开制动蹄。大多数驻 车制动系统是自动调节装置。有一调节器来弥补制动蹄的磨损。在许多汽车上,在 制动蹄磨损或新换的情况下,驻车制动可以进行重新调整。在汽车行驶中,通常通 过重复使用驻车制动系统来进行调整。 当您架车上山时,驻车系统是非常有用的:如若您驾驶一辆手动转向的汽车,且 行驶至停到一个斜面上,您可能会意识到,您没有足够的脚来同时控制离合器、制 动器、和油门。换句话说,当你重新启动时,汽车很可能会轻轻得向后倒退,如果 这时正好有车在您的后面行驶,那么将会出问题了。在这种情况下,驻车制动将很 有用:停车时使用驻车制动。当你再次起动时,放开离合器同时踩下油门,然后松 开驻车制动。这样你就不必将左脚不停得从制动器到离合器,你的右脚从离合器到 油门了。只需稍加练习,你就可以轻松得做到了。此外,如果您在山坡上某人的后 方行驶,记住,要给对方留出向后倒退的空间,尤其是对卡车。有些车可能没有驻 车制动的放松装置,只能在汽车行驶后或倒车时自动松开。记住,定期检查并将您 的驻车制动保持在良好的状态是一个很好的办法,它可能在你的主制动系统失灵时 挽救你的性命! The Brake System The braking system is the most important system in your car. If your brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of your vehicle into thermal energy (heat). When you step on the brakes, you command 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. In modern systems, the master cylinder is power-assisted by the engine. All newer cars have dual systems, with two wheels brakes operated by each subsystem. That way, if one subsystem fails, the other can provide reasonably adequate braking power. Safety systems like this make modern brakes more complex, but also much safer than earlier braking systems. 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 your foots 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. In recent years, brakes have changed greatly in design. Disc brakes, used for years for front wheel applications, are fast replacing drum brakes on the rear wheels of modern cars. This is generally due to their simpler design, lighter weight and better braking performance. The greatest advantage of disc brakes is that they provide significantly better resistance to brake fade compared to drum type braking systems. Brake fade is a temporary condition caused by high temperatures generated by repeated hard braking. It occurs when the pads or shoes glaze due to the great pressure and heat of hard use. Once they cool, the condition subsides. Disc brakes allow greater air ventilation (cooling) compared to drum brakes. Drum brakes are not internally ventilated because if they were, water could accumulate in them. Disc brakes can rapidly fling off any water that they are exposed to, and so they can be well ventilated. Boosters are present in power brake systems, and use the engines energy to add pressure to the master cylinder. Anti-lock (ABS) systems, originally developed for aircraft braking systems, use computer controlled valves to limit the pressure delivered to each slave cylinder. If a wheel locks up, steering input cannot affect the cars direction. With ABS, no matter how hard the pedal is pressed, each wheel is prevented from locking up. This prevents skidding (and allows the driver to steer while panic-braking). As impressive as these advances are, the basic process of converting a vehicles momentum into (wasted) heat energy has not changed since the days of the horse and buggy. To stop a horse drawn carriage, the driver would pull on a lever which would rub on the wheel. But today, with the advent of regenerating brakes on electric vehicles, new ways of recapturing this lost energy are being developed. In these types of electric cars, when you step on the brakes, the motor switches into generator mode, and stores the cars momentum as chemical energy in the battery, to be used again when the light turns green! Disc Brakes Disc brakes use a clamping action to produce friction between the rotor and the pads mounted in the caliper attached to the suspension members. Inside the calipers, pistons press against the pads due to pressure generated in the master cylinder. The pads then rub against the rotor, slowing the vehicle. Disc brakes work using much the same basic principle as the brakes on a bicycle; as the caliper pinches the wheel with pads on both sides, it slows the bicycle. Disc brakes offer higher performance braking, simpler design, lighter weight, and better resistance to water interference than drum brakes. Disc 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 brakes 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 cars now have 4-wheel disc 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. Brake Drums The brake drum is a heavy flat-topped cylinder, which is sandwiched between the wheel rim and the wheel hub. The inside surface of the drum is acted upon by the linings of the brake shoes. When the brakes are applied, the brake shoes are forced into contact with the inside surface of the brake drums to slow the rotation of the wheels. The drums are usually covered with fins on their outer surfaces to increase cooling. They are not cooled internally, because water could enter through the air vent cooling holes and braking would then be greatly impaired. Drum brakes are found on the rear wheels of most older cars, but they are increasingly being fazed out in favor of rear disc brakes. Drum brakes were standard equipment on all four wheels of most cars until the early 70s. Brake Calipers The caliper works like a C-clamp to pinch the pads onto the rotor. It straddles the rotor and contains the hydraulic slave cylinder or wheel cylinder piston(s). One caliper is mounted to the suspension members on each wheel. The caliper is usually mounted onto the spindle, allowing it to deliver the torsional force of the wheel to the chassis via the control arms. Brake hoses connect the caliper to the brake lines leading to the master cylinder. A bleeder valve is located on each caliper to allow air bubbles to be purged from the system. Floating caliper disc brakes, the most common variety, allow the caliper to move from side to side slightly when the brakes are applied. This is because only one pad moves (in relation to the caliper). Some calipers contain two or four seperate pistons. These calipers are fixed in place; i.e., there is no lateral movement like the floating caliper, the pistons take up the slack on each side of the rotor. These are called dual cylinder or dual piston calipers, and are standard equipment on many performance cars. Wheel (Slave) Cylinder Wheel cylinders, also called the slave cylinders, are cylinders in which movable piston(s) convert hydraulic brake fluid pressure into mechanical force. Hydraulic pressure against the piston(s) within the wheel cylinder forces the brake shoes or pads against the machined surfaces of the drum or rotor. There is one cylinder (or more in some systems) for each wheel. Drum brake wheel cylinders are usually made up of a cylindrical casting, an internal compression spring, two pistons, two rubber cups or seals, and two rubber boots to prevent entry of dirt and water. This type of wheel cylinder is fitted with push rods that extend from the outer side of each piston through a rubber boot, where they bear against the brake shoes. In disc brakes, the wheel cylinder is built into the caliper. All wheel cylinders have bleeder screws (or bleeder valves) to allow the system to be purged of air bubbles. As the brake pedal is depressed, it moves pistons within the master cylinder, pressurizing the brake fluid in the brake lines and slave cylinders at each wheel. The fluid pressure causes the wheel cylinders pistons to move, which forces the shoes or pads against the brake drums or rotors. Drum brakes use return springs to pull the pistons back away from the drum when the pressure is released. On disc brakes, the calipers piston seals are designed to retract the piston slightly, thus allowing the pads to clear the rotor and thereby reduce rolling friction. Parking (Emergency) Brakes The parking brake (sometimes called the emergency brake) is a cable-activated system used to hold the brakes continuously in the applied position. The parking brake activates the brakes on the rear wheels. Instead of hydraulic pressure, a cable (mechanical) linkage is used to engage the brake shoes or discs. When the parking-brake pedal is pressed (or, in many cars, a hand lever is pulled), a steel cable draws the brake shoes or pads firmly against the drums or rotors. The release lever or button slackens the cables and disengages the brake shoes. The parking brake is self adjusting on most systems. An automatic adjuster compensates for lining (brake shoe) wear. On many cars, the parking brake is used to re- adjust the brake shoes as they wear in, or when the shoes are replaced. In these systems, the adjustment is made by repeatedly applying the parking brake while backing up. The parking brake can be useful while driving up hills: If youre driving a manual transmission car, and you pull up to a stop on an incline, you might notice that you dont have enough feet to operate the clutch, brake, and gas at the same time. In other words, you will likely roll backwards slightly while getting started again. If a someone pulls up right behind you, this can be a problem. Your parking brake is useful in this situation: Apply the parking brake after you stop. When you want to go, release the clutch while pressing the gas, and release the parking brake. This keeps you from having to quickly switch your left foot from the brake to the clutch, or your right foot from the brake to the gas pedal. A little practice, and youll be able to do it smoothly. Also, remember if you pull up behind someone who is stopped on a hill, give them extra room to roll back a little. Especially if its a truck. Some cars have no parking brake release! They automatically release the parking brake when the car is placed in drive or reverse. Remember, its a good idea to test the parking brake periodically and keep it in good condition. It may save your life if the main braking system fails! 河北科技师范学院河北科技师范学院 毕业论文(设计)外文翻译毕业论文(设计)外文翻译 题 目: 制动系统 学 生 姓 名: 张海燕 指 导 教 师: 郑立新 系 别: 机械电子系 专业 、班级: 机械设计制造及自动化 0204 班 完 成 时 间: 2005 年 12 月 20 日 河北科技师范学院教务处制河北科技师范学院教务处制 河北科技师范学院河北科技师范学院 毕毕 业业 论论 文(设文(设 计)计) 档档 案案 题 目:汽车液压制动驱动机构的设计 学 生 姓 名: 张海燕 指 导 教 师: 郑立新 系 别: 机械电子系 专业 、班级:机械设计制造及自动化 0204 班 完 成 时 间: 2006 年 6 月 24 日 河北科技师范学院教务处制河北科技师范学院教务处制 河北科技师范学院河北科技师范学院 毕业论文(设计)工作总结毕业论文(设计)工作总结 学 生 姓 名: 张海燕 指 导 教 师: 郑立新 系 别: 机械电子系 专业 、班级:机械设计制造及其自动化 0204 班 完 成 时 间: 2006 年 6 月 23 日 河河 河北科技师范学院教务处制河北科技师范学院教务处制 河北科技师范学院河北科技师范学院 毕业论文(设计)文献综述毕业论文(设计)文献综述 题 目: 液压制动系统的发展 学 生 姓 名: 张海燕 指 导 教 师: 郑立新 系 别: 机械电子系 专业 、班级: 机械设计制造及自动化 0204 班 完 成 时 间: 2005 年 12 月 23 日 河北科技师范学院教务处制河北科技师范学院教务处制 1 毕业论文开题报告 姓姓 名名张海燕张海燕 学学 号号 04110201250411020125 专专 业业机械设计制造及机械设计制造及 自动化自动化 班班 级级02040204 班班 题题 目目汽车液压制动驱动机构的设计汽车液压制动驱动机构的设计 1 1本选题的目或意义,该选题目前研究现状、水平和发展趋势本选题的目或意义,该选题目前研究现状、水平和发展趋势 汽车 制动系是用以强制行驶中的汽车减速或停车、使下坡行驶的汽车的车速保持稳定 以及使已停驶的汽车在原地驻留不动的机构。随着高速公路的迅速发展和车速的提 高以及车流密度的日益增大,为了保证行车安全,汽车制动系的工作可靠性显得日 益重要。也只有制动性能良好、制动系工作可靠的汽车,才能充分发挥其动力性能。 最 I 最原始的制动控制只是驾驶员操纵一组简单的机械装置向制动器施加作用力,这 时的 车辆的质量比较小,速度比较低,机械制动虽已满足车辆制动的需要,但随着汽车自 质量 的增加,助力装置对机械制动器来说已显得十分必要。随着科学技术的发展及汽车 工业 的发展,尤其是军用车辆及军用技术的发展,
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