513 20馬力輪式拖拉機的半軸與制動器設(shè)計（有cad圖等）
513 20馬力輪式拖拉機的半軸與制動器設(shè)計（有cad圖等）,513,20馬力輪式拖拉機的半軸與制動器設(shè)計（有cad圖等）,20,馬力,輪式拖拉機,制動器,設(shè)計,cad
Brake system
Automobile brake is the most important system in cars.Brake are actually energy conversion ,which convert the kinetic energy of the vehicle into thermal energy .When stepping on the brakes,the drive commands a stopping force ten times as powerful as the force that puts the cars in motin .The brakeing system can exert thousands of pounds of pressure on each of the four brakes.
Each vehicle must have two indenpent brake systems for safety.The main brake system which is locate under the hood and is directly connect to the brake pedal is hydraulically operated and is called the service brake system.The secondary or parking brake system is mechanically operated.To increase safety ,most modern car brake system are broken into two circuits,with two wheels on each circuit.There is a fluid-filled cylinder,called the master cylinder .It supplies pressure to hoth circuits of the car ,and if a fluid leak occurs in one circuit ,only two of the wheels will lose their brakes and the car will be stopped.
Why that pushig down on the brake pedal can slow a car to stop? How dose the car transmits the force from the driver’leg to its wheel? It is the work that brakes did.
Layout of Typical Brake system When depressing the breke pedal ,the car transmits the force the drive’s foot to its brakes through a fluid.Since the actual brakes require a much greater force than the drive could apply with his leg ,the car must also multipy the force of the driver’s foot.It dose this in two ways: mechanical advantage and hydraulic force multiplication .
Leverge The pedal is designed in such a way that it can multiply the force from the driver’s leg several times before any force is even transmitted to the brake fluid.
In the figure above ,a force F is being applied to the left end of the lever.The left end of the lever is twice as long 2X) as the right end (x).Therefore ,on the right end of the lever a force of 2F is available,but it acts through half of the distans (Y) that the left end moves (2Y) .Changing the relative lengths of the left and right ends of the lever changes the mulitipliers.
Hydraulic Brake Systems The hydraulic system is that force applied at one point is thansmitted to another point using an incompressible fluid , almost alwaays an oil of some sort .Most brake systems also muitiply the force in the process .The great thing about hydraulic systems is that the pipe connecting the two cylinders can be any length and shape , allowing it to snake through all sorts of things separating the two pistons .The pipe can also fork ,so that one master cylinder can drive more than one salve cylinder if desired .The other neat thing about a hydraulic system is that it makes force multiplication fairly easy . In a hydralic system , all you have to do change the size of one piston and cylinder to the other .
The automobile brake systems are divided into three types of service brake combinations:drum brake , disc brakes and disc-drum combinations.
Drum Brake It uses an internal expanding brake shoe with the lining attactet , working within the confines of a rotating brake surface called a brake drum .The brake shoe diameter is expanded to contact the brake surface by a hydraulic cylinder that is referred to as a wheel cylinder . With drum brake , the fluid is forced into the wheel cylinde which pushed the brake shoes out so that the friction lining are pressed againtst the drum , and cause the wheel to stop .
Power brakes back in the day , when most cars had drum brakes ,power brakes were not really necessary ---- drum brakes naturally provide some of their own power assist .Since most cars today have disc brakes ,at least on the front wheels , they need power brakes,Without this device ,a lot of drivers would have very tired legs .
The brake booster use Vacuum from the engine to multipiy the force that your foot applies to the master cylinder .
Disc Brakes Most modern cars have disc brake on the front wheels , and some have disc brakes on all four wheels ,Disc brakes employ a brake disc that rotates with the wheel ,so it is usually referred to as a brake rotor . On a disc brake , the fluid from the master cylinder is forced into a caliper where it presses against a piston ,in—turn , squeezes two brake pads against the disk 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.
The most common type of disc brake on modern cars is the single-piston floating caliper.
Self-Adjusting brakes The single-piston floating-caliper disc brake is self-centering and self-adjusting .The caliper is able to slide from side to side so it will move to the center each time the brakes are applied .Also,since there is no spring to pull the pads away from the disc ,the pads always stay in light contact with the rotor .This is important because the pistons in the brakes are much larger in diameter than the ones in the master cylinder .If the brake pistons retracted into their cylinders ,it might take several applications of the brake pedal to pump enough fluid into the brake cylinder to engage the brake pads.
Self-Adjusting disc brake Older cars had dual or four-pistin fixed-caliper desiger .A piston on each side of the rotor pushed the pad on that side .This design has been largely eliminated because single-piston designs are cheaper and more reliable .
Emergence Brakes In cars with disc brakes on all four wheels ,an emergency brake has to be actuated by a separate mechanism than the primary brakes in case of a total primary brake failure .Most cars use a cable to actuate the emergency brake .Some cars with four-wheel disc brakes have a separate drum brake integrated into the hub of the rear wheels .This drum brake is only for the emergency brake sysem ,and it is actuated only by the cable;it has no hydraulics .
Parking Brakes Cars also have the parking brake system .It is used to hold one or more of the vehicle brakes in an applied position for an extended period of time .This brake system must be capable of holding the vehicle on a grade and bringing the vehicie to a stop if the service brakes fail .The parking brake system used on most current model passenger vehicles operates by applying two rear-wheel brakes through a mechanical system of cable and levers.
There are air brakes ,anti-lock brakes ,too .The forme used in heavy trucks and utilizes compressed air as a source of force to stop the truck .The latter used for solving the lockup problem: it can rapidly pump the brakes whenever the system detects a wheel that is locked up .This pumping of the brakes occurs at ten or more times a second ,far fasrer than a human can pump the brake manually.
Post-Sale Service and Callback
The automobile post-sale service means the sale branch provides all the technical service to the customer before or after they buy the car .It may carry on in pre-sale ,or when selling carries on .What but are more is sells after the vehicles ,cerris on the quality guarantee ,the routine maintenance ,the repair ,the technical consultation and the spare parts supply according to the deadline and so on a series of work .
In recent years ,the products performances ,product qualities and product prices are almost convergence the same among those famous international automobile companies .As a result ,the focus of competition in the market focus and transfer to post-sale .Post-sale functions should be enable to use good car products and to create the best returns ,and thus can prove the successful post-sale work .
A perfect post-sale service should have two function : to serve both customers and companies themselves .For customers ,the post-sale service could satisfy them and help them solve problems ;for the companies themselves ,it could accurately reflect product utility information ,quality information ,and important social information ,so that the company can make right decisions based on them .
Automobile is the most typical product which highly unifies the sale and the post-sale service .In the intermation market ,one important criterion for automobile sale agent is whethe they have and fulfill post-sale service .When a customer wants to purchase a car ,the first thing he asks is where to repaire the car and whether there are spare-parts .
Only getting postive replies ,will he think of other things .Big automobile companies from Eupope ,the US and Japan all recognize that the first car is sold by sales personnel ,but the second car mainly relies on good post-sale service .
The automobile is a big product ,so it is very difficult to fulfill all kinds of post-sale service only depending upon manufaturers .Usually ,a service network undertakes all technical service for manufacturers.In foreign countries ,the post-sale service network is usually linked with sales network .So it can provide technical service while selling automobile .And the post-sale service network is composed by distributors ,agents and repairing shops .
Post-sale service itself belongs to the technical service category.
Automobile is hightly technology-intensive ,so the post-sale service includes technical guidance ,technical consultation ,and technical demonstration and so on .Main points which need to be introduced to the society ,dealers ,post-sale service network and customers are completely done by post-sale department .
On the other hand ,as a post-sale service man ,one should make sure that you have satisfied your customers when doing your work ,and should make it clear that you want to know if there are any problems with you work ,no matter when they develop .
Since you made the project ,you are naturally the best person to service it ,if and when the need arises .Make this clear to your client .Nobody likes callbacks ,and if you’ve done your job well ,you should have few ,if any ,for months or years after the installation or delivery.But let the client know that for repairs that result from ordinary use ,you’ll be glad to keep your work looking and working like new---for a modest fee ,of course .
If ,however ,problems arise that are clearly due to shoddy workmanship ,it is incumbent on you to correct them free of charge .This is ,of course ,perhaps the best reason to get it right the first time .
There’s no trick to determine whether you are being called back because of a problem due to you workmanship or the client’t use of the unit .Like everything else we’ve covered in this series ,doing right by your customers is just a matter of honesty .Put honesty into practice as part of your selling system and you’ll find that it is the best way to do what is right for your business ,too .
A checklist for maintaining good customer relations:
Do anything you can to help the client visualize in advance how the finished project will look .
Don’t give ballpark prices unless you already have a well established relationship with the client .
Use customers as references ,but only when you are sure they are totally satisfied.
Tell customers you want to know if there are problems with your work and that you can provide any routine service .
In everything you do ,be honest with your client .
Automobile callback system originated from the U.S in 1960s .Now it is not new in the U.S.,European countries ,Japan and South Korea .The U.S.has the longest history of automobile callback and the most strict regulations .Until now ,the American grand has totally recalled more than 200 million vehicles since 1966 ,and more than 24 million tires ,including passenger vehicle ,trucks ,buses ,motorcycles and so on ,And nearly all auto manufactures in the world have recalled cases in the U.S.
China’s Flaw Automobile Prosuct Management Stipulation was implemented since October1 ,2004 .Automobile is the machine which is assembled by tens of thousands of components and it is not strang to have this kind of flaw or that kind in materials or designs .But most flaws are recessive ,so they will be gradually exposed after using a period of time and people can then realize the flaw’s existence .Sometimes some batch of vehicle components processing ,assembly or material formula change ,and they possibly bring the flaws .The scope of callback system is extremely explicit ,that is the flaw has to be associated with safety and should appear in the batch .Recall system mainly aims at the systematic and unified flaws which are related with safety and existing in one batch of vehicles .The goal of the automobile recall is to eliminate the flaw and hidden danger ,ensure the public security ,the public benefit and the social economic order .
制動系統(tǒng)
制動系統(tǒng)是汽車中最重要的系統(tǒng)，它實際上是個能量轉(zhuǎn)換裝置，它把動能轉(zhuǎn)化為內(nèi)能。當(dāng)踩在制動器上時，司機就發(fā)出了制動指令，它的制動能量是啟動時的十倍，制動系統(tǒng)把一千磅的壓力施給了汽車的四個輪子。
為安全起見，每輛車都必須有兩套獨立的制動系統(tǒng)。主動系統(tǒng)被稱作制動系統(tǒng)，是由液壓操縱的，它位于視窗的下部，直接與踏板相連接；副系統(tǒng)是由汽車自動系統(tǒng)操作的。處于安全原因，多數(shù)現(xiàn)代汽車制動系統(tǒng)被分成兩個部分回路，每個回路系統(tǒng)作用在兩個車輪上，有一個稱作主汽缸的流體汽缸，提供了兩個不同回路系統(tǒng)的壓強。如果有一個回路系統(tǒng)不再有氣密性，那意味著只有兩個車輪失去控制，汽車仍然會停下來。
為什么踩在踏板上會使車停下來呢？汽車是怎么把司機腳上的力量傳輸?shù)杰囕喩夏兀科鋵?，所有的工作都是制動系統(tǒng)做的。當(dāng)踏上踏板時，汽車就會通過流體把司機的腳力傳輸過去?；谑聦嵣系闹苿有枰艽蟮哪芰浚@不是腳力所能達到的。汽車因此要擴大腳力的能量，有兩種方法：機械原理（杠桿作用）和流體壓力放大法。
機械原理 剎車板的設(shè)計原理是把司機的腳力放大幾倍于任何力量傳送之前，甚至相當(dāng)于流體制動系統(tǒng)的力量。
上圖顯示，在杠桿的左端提供一個為F的力，杠桿左臂長（2X）是右臂長（X）的2倍，那么杠桿的右端就有2F的力可利用，相應(yīng)的操縱中就有左臂移動2倍的高（2Y）相當(dāng)于右臂的高度（Y）。改變左右臂長的比率，就會改變力的放大倍數(shù)。
液壓制動系統(tǒng) 液壓制動系統(tǒng)原理是用諸如油類物質(zhì)的不易被壓縮原理，液壓把力從一點傳送到另一點。多數(shù)制動系統(tǒng)同樣都是把力量放大的過程，液壓制動系統(tǒng)優(yōu)點在于液壓管以任意長度和形狀連接著汽缸，液壓可以任意穿越兩個活塞系統(tǒng)的各個部分；它的另一個優(yōu)點是液壓系統(tǒng)放大效應(yīng)操作非常簡單。流體系統(tǒng)中，要做的只有改變汽缸的大小和連接方式。
汽車制動系統(tǒng)有3中不同制動系統(tǒng)的組合：鼓式制動器、盤式制動器、鼓式-盤式混合制動器。
鼓式制動器 它是用內(nèi)置剎車片工作的。它附有襯料，作用于被成為剎車鼓的旋轉(zhuǎn)限定表面。剎車制動片的放大效率是由液壓汽缸使其膨脹觸及制動器來實現(xiàn)的，這是汽缸效益，在鼓式制動器作用下，液壓被迫流入汽缸中，就實現(xiàn)了由其把剎車制動片壓向外部，同時與制動內(nèi)襯緊壓住剎車鼓，引起的摩擦就會車輪停下來。
動力制動器 在以前，多數(shù)汽車擁有鼓式制動器，它自動提供動力制動幫助，動力制動器就顯得無足輕重了。由于現(xiàn)在的汽車配備了盤式制動器，動力制動器才顯得舉足輕重了，至少是作用于前輪的。沒有動力制動器，司機就會很累。制動增強儀利用真空狀態(tài)使引擎把力放大，再通過司機的腳傳輸給主汽缸。
盤式制動器 現(xiàn)代汽車多數(shù)前輪配有盤式制動器，有的汽車前后輪都有配備。盤式制動器控制著旋轉(zhuǎn)輪上的盤式制動片，因此它也稱作旋轉(zhuǎn)制動器。在制動盤上，流體從控制儀被解壓到活塞對面的合流處，活塞間接地控制制動盤，活塞擠壓著輪子制動盤上的兩個制動墊，從而使車子減速和停下來。這和自行車制動相似——制動墊與輪圈摩擦而產(chǎn)生摩擦力使車停下來。
現(xiàn)代盤式制動器常見類型是單活塞浮動式制動器。
自動調(diào)節(jié)制動器，單汽缸浮球自動盤是自我調(diào)節(jié)、自我為中心的。浮球能夠從一邊滑向另一邊，在制動器的調(diào)節(jié)下可以移至中心處理處。
自動調(diào)節(jié)盤式制動器，老式汽車擁有雙汽缸或四汽缸固定浮動器的設(shè)計。這種設(shè)計已經(jīng)被大規(guī)模地淘汰，因為單汽缸既廉價又可靠性高。
緊急制動系統(tǒng) 四輪裝有盤式制動器的汽車，緊急制動儀是在正常制動失效的情況下起作用的。它采用纜索啟動緊急系統(tǒng)，也有一些汽車四輪全是盤式制動的。在此基礎(chǔ)上配備有主動輪上鼓式制動儀，鼓是制動儀為應(yīng)緊急制動，是由纜索啟動而不是液壓啟動。該系統(tǒng)是獨立系統(tǒng)。
停車制動系統(tǒng) 汽車也擁有停車制動系統(tǒng)，它必須能夠在正常制動失效的情況下，使車保持某種狀態(tài)或使車停下來。該系統(tǒng)流行于現(xiàn)今公共車輛，她由纜索和杠桿通過機械操作實現(xiàn)的，它作用于主動制動器。
制動系統(tǒng)還有氣流制動和反鎖制動，前者用于中型卡車，利用壓縮空氣作為制動力使車停止；后者用于上鎖的問題：一經(jīng)發(fā)現(xiàn)上鎖可以立即啟動系統(tǒng)，這類泵式制動方式作用時間僅為10多秒，遠遠快于人類手動啟動操作制動系統(tǒng)。
售后服務(wù)與召回
汽車售后服務(wù)泛指顧客接車前后，由銷售部門為顧客所提供所有的技術(shù)性服務(wù)工作。它可能在售前進行，也可能在售時進行。但更多的是在車輛售出后，按期限所進行的質(zhì)量擔(dān)保、日常維護、修理、技術(shù)咨詢及配件供應(yīng)等一系列的工作。
近年來，國際上著名的汽車公司的產(chǎn)品性能、產(chǎn)品質(zhì)量、產(chǎn)品價格積分趨于一致，結(jié)果導(dǎo)致市場競爭的焦點都在向售后服務(wù)集中和轉(zhuǎn)移。售后服務(wù)的功能應(yīng)該覆蓋到能為用戶想到的一切服務(wù)內(nèi)容。通過服務(wù)，使用戶用好汽車產(chǎn)品，并創(chuàng)造最好的效益，這才能證明售后服務(wù)的成功。
完善的售后服務(wù)應(yīng)具備對外和對內(nèi)的兩大功能。對外是能安撫用戶，為用戶解除后顧之憂；對內(nèi)功能是準(zhǔn)卻及時地反饋產(chǎn)品使用信息、質(zhì)量信息以及各種社會的重要信息，供企業(yè)做出正確的決策。
汽車產(chǎn)品是銷售和售后服務(wù)都必須高度結(jié)合的最典型產(chǎn)品。國際上，是否具備售后服務(wù)能力并履行售后服務(wù)義務(wù)是 汽車代理的重要標(biāo)準(zhǔn)。當(dāng)一顧客買車是，他首先提出的問題是這種車型在哪里能維修，有沒有備件供應(yīng)。只有得到肯定的答復(fù)后，他才問其他想了解的問題。當(dāng)今，歐、美、日的各大汽車公司都認(rèn)為，第一臺汽車是由銷售人員賣掉，第二臺是靠售后服務(wù)出色而賣出去。
汽車是大生產(chǎn)的產(chǎn)品，很難只依靠制造商自身的力量，圓滿完成“售后服務(wù)”諸多任務(wù)。通常是在社會上組織一個龐大的服務(wù)網(wǎng)絡(luò)，這個網(wǎng)絡(luò)代表制造商承擔(dān)用戶的全部技術(shù)工作。國外汽車的售后服務(wù)網(wǎng)絡(luò)通常是和汽車經(jīng)銷銷商網(wǎng)絡(luò)相結(jié)合，在經(jīng)銷汽車的同時又提供技術(shù)服務(wù)。它通常由汽車分配商、汽車代理商、汽車維修點三個層次組成。
售后服務(wù)本身屬于技術(shù)服務(wù)的范疇。由于汽車產(chǎn)品的高度技術(shù)密集，汽車產(chǎn)品的售后服務(wù)工作必然包括對用戶的技術(shù)指導(dǎo)、技術(shù)咨詢、技術(shù)示范；同時包含著汽車企業(yè)對自己售后服務(wù)網(wǎng)絡(luò)人員的技術(shù)培訓(xùn)、技術(shù)示范、技術(shù)指導(dǎo)等。通常，凡是需要汽車企業(yè)向社會、經(jīng)銷商、售后服務(wù)網(wǎng)絡(luò)和用戶宣傳和交代的技術(shù)要點，全部有售后服務(wù)部門來完成。
另一方面，作為售后服務(wù)人員應(yīng)具備以下的素質(zhì)：服務(wù)時確信你滿足了你的顧客，并表明你想知道你的工作是否存在任何的問題，不論問題何時出現(xiàn)。既然你做了這個項目，當(dāng)如果和需要出現(xiàn)時你自然就是最佳的服務(wù)人選，使你的用戶明白這一點。每人喜歡召回，如果你的工作做得更好，此事應(yīng)該不會發(fā)生，若有也會在交付使用幾個月或幾年以后。但告訴顧客一般的修理，你將會繼續(xù)高興地為他們服務(wù)——當(dāng)然，要適當(dāng)收費。
但是，如果出現(xiàn)的問題明顯屬于質(zhì)量問題（通常出現(xiàn)在交付的幾天或星期內(nèi)），你就有責(zé)任免費為其改正。當(dāng)然這也許是首次維修的最佳理由。不要妄自臆斷你是否被招來是由于你的技術(shù)或顧客的使用問題，像上面我們所提到的，顧客能做正確事實。實踐中融誠實為銷售系統(tǒng)的一部分，你會發(fā)現(xiàn)這是正確經(jīng)營業(yè)務(wù)的最佳方式。
維護良好的客戶關(guān)系的幾點要素：
做你能做的任何事，幫助顧客形象化地預(yù)知將要完成的項目怎么樣。
除非你和顧客建立了良好的合作關(guān)系，否則不要給出低價。
只有當(dāng)你肯定他們是完全滿意時，才使用顧客作為向他人推薦的來源。
告訴顧客，你想知道是否你的工作還有問題，并且你能提供任何定期服務(wù)。
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汽車召回制度是指已經(jīng)投放市場的汽車發(fā)現(xiàn)由于制造或設(shè)計方面原因存在缺陷，不符合有關(guān)法規(guī)標(biāo)準(zhǔn)，有可能導(dǎo)致安全和環(huán)保問題，廠家必須及時向國家有關(guān)部門報告該產(chǎn)品的缺陷及其原因、改造措施，提出召回申請，經(jīng)批準(zhǔn)后，對在用車輛進行改造以消除事故隱患，同時廠家有義務(wù)讓顧客及時了解情況。
汽車召回制度創(chuàng)始于20世紀(jì)60年代的美國，發(fā)展至今，在美國、歐洲、日本、韓國等國家早已不是一件新鮮事。其中，美國的召回史最長，相關(guān)的管理程序也最嚴(yán)密。從1966年至今美國已總計召回2億多輛整車，2400多萬條輪胎，涉及的車型有轎車、客車、大客車、摩托車等多種，全球幾乎所有的汽車制造廠在美國曾經(jīng)經(jīng)歷過召回的案例。
我國的《缺陷汽車產(chǎn)品召回管理規(guī)定》從2004年10月1日其實施。汽車是由上萬之零件組裝而成的機器，在設(shè)計、裝配或材料上存在這樣或那樣的缺陷不奇怪，但大多數(shù)缺陷都市隱性的，它往往要經(jīng)歷一段時間后的使用后才逐漸顯露其缺陷的后果，人們才能察覺缺陷的的存在?；蛘吣撑嚨牧慵庸ぁ⒀b配或材料配方的變換，也有可能產(chǎn)生缺陷問題。但不管怎樣，召回制度的范圍是十分明確的，就是這一召回缺陷必須是與“安全”相關(guān)的，并且是批量出現(xiàn)的。召回主要針對系統(tǒng)性、統(tǒng)一性與安全有關(guān)的缺陷，這個缺陷必須在同一批車輛上都存在，而且是和安全相關(guān)的。汽車召回的目的是為了消除缺陷汽車安全隱患，維護公共安全、公眾利益和社會經(jīng)濟秩序。
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