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湖 南 科 技 大 學(xué) 畢 業(yè) 設(shè) 計(jì)（論 文）任 務(wù) 書 機(jī) 電 工 程 學(xué)院 機(jī) 械 設(shè) 計(jì) 制 造 及 其 自 動(dòng) 化 系 系主任: （簽名） 2015 年 3 月 8 日 學(xué)生姓名: 學(xué)號(hào):專業(yè): 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 1 設(shè)計(jì)（論文）題目及專題： 雙柱機(jī)械式汽車舉升機(jī) 2 學(xué)生正式設(shè)計(jì)時(shí)間：自 2015 年 3 月 8 日開始至 2014 年 5 月 20 日止 3 設(shè)計(jì)（論文）所用資源和參考資料： 1）圖書館查閱有關(guān)汽車舉升機(jī)方面的書籍及科技期刊； 2）參閱機(jī)械設(shè)計(jì)手冊查閱與課題有關(guān)資料； 3）上網(wǎng)查閱汽車舉升機(jī)的設(shè)計(jì)方案，收集有關(guān)圖片及圖紙資料。 4 設(shè)計(jì)（論文）應(yīng)完成的主要內(nèi)容： 1)本汽車舉升機(jī)的簡介和發(fā)展概況，及其基本的工作原理； 2)本汽車舉升機(jī)的結(jié)構(gòu)分析，舉升機(jī)構(gòu)，箱體，托臂機(jī)構(gòu)，安全裝置等結(jié)構(gòu)原理方案及選擇設(shè)計(jì)說明； 3)本汽車舉升機(jī)舉升機(jī)構(gòu)和安全裝置的設(shè)計(jì)與校核，及其重要結(jié)構(gòu)參數(shù)等的設(shè)計(jì)計(jì)算說明； 4)本汽車舉升機(jī)，機(jī)構(gòu)的設(shè)計(jì)與校核，及其重要零件的技術(shù)設(shè)計(jì)計(jì)算說明等； 5 提交設(shè)計(jì)（論文）形式（設(shè)計(jì)說明與圖紙或論文等）及要求： 1)雙柱機(jī)械式舉升機(jī)總裝配圖、舉升機(jī)零部件圖等共折合A0不少于2.5張（較復(fù)雜零件數(shù)控加工程序一份3頁以上可抵圖紙0.5A0）； 2)設(shè)計(jì)計(jì)算說明書一份（小四號(hào)字打印不少于40頁，文中可插自畫圖和表格，規(guī)范見校文件）； 3)刻碟一張（內(nèi)容為本設(shè)計(jì)的電腦設(shè)計(jì)圖和設(shè)計(jì)計(jì)算說明書）； 6 發(fā)題時(shí)間： 2015 年 03 月 08 日 指導(dǎo)教師： （簽名） 學(xué) 生： （簽名） 湖 南 科 技 大 學(xué) 開題報(bào)告 學(xué) 生 姓 名： 學(xué) 院： 機(jī)電工程學(xué)院 專業(yè)及班級(jí)： 學(xué) 號(hào)： 指導(dǎo)教師： 2015 年 3 月 18 日 湖南科技大學(xué)2015屆畢業(yè)設(shè)計(jì)（論文）開題報(bào)告 題 目 雙柱機(jī)械式汽車舉升機(jī)設(shè)計(jì) 作者姓名 學(xué)號(hào) 所學(xué)專業(yè) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 1、 研究的意義，同類研究工作國內(nèi)外現(xiàn)狀、存在問題（列出主要參考文獻(xiàn)） 研究意義：汽車舉升機(jī)在汽保行業(yè)中占有重要的地位。汽車舉升機(jī)作為汽保行業(yè)中最基本、最典型、最重要的維修設(shè)備之一，是根據(jù)維修工況，將需要維修的汽車安全可靠地從一個(gè)高度提升至另一合適高度的設(shè)備，以便于工人的維修工作，具有至關(guān)重要及難以替代的作用。 國內(nèi)現(xiàn)狀：我國的舉升機(jī)起步較晚，20世紀(jì)80年代初才根據(jù)外國的技術(shù)生產(chǎn)。舉升機(jī)由于便于技師維修工作，逐漸替代了以前通用的“地溝”模式。隨著我國汽車工業(yè)的繁榮，伴隨著形成了一個(gè)龐大的汽車后市場，汽車舉升機(jī)的市場迅速擴(kuò)大。2000年，舉升機(jī)產(chǎn)品形式和種類發(fā)展成多種多樣，成為汽車維修行業(yè)取得二級(jí)維修資質(zhì)必備的設(shè)備。隨著汽車保有量的不斷增多，私人購買成為購車的主流，售后市場得到蓬勃發(fā)展，汽車舉升機(jī)成為一種必不可少且使用頻率極高的汽車維修設(shè)備，舉升機(jī)生產(chǎn)廠家相繼出現(xiàn)，舉升機(jī)產(chǎn)品系列成百上千，但國產(chǎn)舉升機(jī)質(zhì)量良莠不齊。如何提高舉升機(jī)的性能與產(chǎn)品的市場競爭力是廠家最關(guān)心的問題之一。 存在問題：1、雙柱機(jī)械式舉升機(jī)同步性及升降是否平穩(wěn) 2、舉升機(jī)的安全裝置 3、舉升機(jī)機(jī)械磨損較大 2、 研究目標(biāo)、內(nèi)容和擬解決的關(guān)鍵問題（根據(jù)任務(wù)要求進(jìn)一步具體化） 研究目標(biāo)： 通過合理整和已有的設(shè)計(jì)，閱讀大量文獻(xiàn)，掌握機(jī)械設(shè)計(jì)的基本步驟和要求，以及傳統(tǒng)的機(jī)械制圖的步驟和規(guī)則；學(xué)會(huì)用AutoCAD,SolidWorks等三維軟件進(jìn)行基本的二維或三維建模和制圖，同時(shí)提高分析問題及解決問題的能力。提出將各種設(shè)計(jì)方法互相結(jié)合,針對不同的設(shè)計(jì)內(nèi)容分別應(yīng)用不同的方法,以促進(jìn)其設(shè)計(jì)過程方法優(yōu)化、設(shè)計(jì)結(jié)果精益求精。 研究內(nèi)容： （1）舉升機(jī)構(gòu)設(shè)計(jì)； （2）立柱結(jié)構(gòu)設(shè)計(jì)； （3）重要連接件校核； （4）支撐機(jī)構(gòu)設(shè)計(jì)； （5）安全裝置設(shè)計(jì)； （6）整體結(jié)構(gòu)布局； 擬解決的關(guān)鍵問題： 舉升機(jī)同步設(shè)計(jì) 舉升機(jī)的安全裝置 舉升機(jī)機(jī)械磨損較大 3、 特色與創(chuàng)新之處 采用雙電機(jī)方案，通過電路控制實(shí)現(xiàn)同步運(yùn)動(dòng)； 選擇合適的材料制造螺母，延長使用壽命； 螺紋自鎖和導(dǎo)軌鉗制器用以鎖緊安全裝置 4、 擬采取的研究方法、步驟、技術(shù)路線 研究方法： 觀察法 觀看制動(dòng)器拆裝視頻 文獻(xiàn)研究法 查閱網(wǎng)絡(luò)文章，閱讀文獻(xiàn)和論文 模擬法 建立solidworks三維模型 數(shù)學(xué)法 用數(shù)學(xué)經(jīng)驗(yàn)公式對制動(dòng)器的制動(dòng)力進(jìn)行分析 步驟： 第一階段，在1月到3月之間利用寒假時(shí)間進(jìn)行知識(shí)儲(chǔ)備，技術(shù)儲(chǔ)備。通過查閱網(wǎng)絡(luò)文章，閱讀文獻(xiàn)和論文，搜索一些圖紙等途徑對舉升機(jī)的結(jié)構(gòu)初步掌握，完成雙柱機(jī)械式舉升機(jī)初步方案構(gòu)思。 第二階段，在3月到4月之間進(jìn)行詳細(xì)設(shè)計(jì)，有舉升機(jī)的同步運(yùn)動(dòng)設(shè)計(jì)，舉升機(jī)的安全裝置選擇和設(shè)計(jì)，解決機(jī)械磨損較大的問題，以及舉升機(jī)的整體結(jié)構(gòu)設(shè)計(jì)，并利用SolidWorks建立三維模型仿真，畫出重要零件圖和裝配圖。寫出設(shè)計(jì)說明書。 第三階段，在5月份，畫出重要零件圖，繪制裝配草圖，繪制裝配圖，寫出設(shè)計(jì)說明書，查漏補(bǔ)缺，完善畢業(yè)設(shè)計(jì)。 技術(shù)路線： 首先了解本論題的研究狀況，明確研究目的，確定研究方向；其次，進(jìn)一步搜集閱讀資料并研讀文獻(xiàn)，做好相關(guān)的記錄，形成論題提綱，確定研究方案；再次，實(shí)施研究計(jì)劃，現(xiàn)場測繪，完成相應(yīng)計(jì)算，建立三維仿真模型，完成零件圖裝配圖的繪制。最后，完成預(yù)期成果，編寫設(shè)計(jì)說明書，反復(fù)修改，完成設(shè)計(jì)。 5、 擬使用的主要設(shè)計(jì)、分析軟件及儀器設(shè)備 solidworks應(yīng)用軟件建模，CAD應(yīng)用軟件繪圖 6、參考文獻(xiàn) [1] 機(jī)械設(shè)計(jì)手冊編委會(huì).機(jī)械設(shè)計(jì)手冊單行本帶傳動(dòng)和鏈傳動(dòng)[M].北京:機(jī)械工業(yè)出版社,2007.2. [2] 機(jī)械設(shè)計(jì)手冊編委會(huì).機(jī)械設(shè)計(jì)手冊單行本帶彈簧 摩擦輪及螺旋傳動(dòng) 軸[M].北京:機(jī)械工業(yè)出版社,2007.2. [3] 成大先.機(jī)械設(shè)計(jì)手冊單行本軸承[M].北京:化學(xué)工業(yè)出版社,2004.1. [4] 濮良貴，紀(jì)名剛.機(jī)械設(shè)計(jì)[M].北京:高等教育出版社,2006.5. [5] 曲健俊.含油MC尼龍的摩擦磨損特性及應(yīng)用[J].工程塑料應(yīng)用,2000,28卷（11期）:22-24頁. [6] 上官紅喜.一種雙柱汽車舉升機(jī)的設(shè)計(jì)[J].液壓與氣動(dòng),2013（13期）:106-109頁. [6] 郭武，黃澤星，吳上生.汽車舉升機(jī)的發(fā)展趨勢分析[J].應(yīng)用研究,2011:75-79頁. [7] 劉鴻文.材料力學(xué)I[M].北京:高等教育出版社,2011.1. [8] 孫桓，陳作模，葛文杰.機(jī)械原理[M].北京:高等教育出版社,2006.5. [8] 高為國，鐘利萍.機(jī)械工程材料[M].長沙:中南大學(xué)出版社,2012.9. [9] Neil Sclater, Nicholas P. Chironis.Mechanisms and Mechanical Devices Sourcebook[M].北京:機(jī)械工業(yè)出版社,2007.2. [8] 成大先.機(jī)械設(shè)計(jì)手冊第五版第一卷[M].北京:化學(xué)工業(yè)出版社,2007.11. [9] 成大先.機(jī)械設(shè)計(jì)手冊第五版第二卷[M].北京:化學(xué)工業(yè)出版社,2007.11. 注： 1、開題報(bào)告是本科生畢業(yè)設(shè)計(jì)（論文）的一個(gè)重要組成部分。學(xué)生應(yīng)根據(jù)畢業(yè)設(shè)計(jì)（論文）任務(wù)書的要求和文獻(xiàn)調(diào)研結(jié)果，在開始撰寫論文之前寫出開題報(bào)告。 2、參考文獻(xiàn)按下列格式（A為期刊，B為專著） A：[序號(hào)]、作者（外文姓前名后，名縮寫，不加縮寫點(diǎn)，3人以上作者只寫前3人，后用“等”代替。）、題名、期刊名（外文可縮寫，不加縮寫點(diǎn)）年份、卷號(hào)（期號(hào)）：起止頁碼。 B：[序號(hào)]、作者、書名、版次、（初版不寫）、出版地、出版單位、出版時(shí)間、頁碼。 3、表中各項(xiàng)可加附頁。 4 湖 南 科 技 大 學(xué) 英文文獻(xiàn)翻譯 學(xué) 生 姓 名： 段 偉 學(xué) 院： 機(jī)電工程學(xué)院 專業(yè)及班級(jí)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 學(xué) 號(hào)： 1106060112 指導(dǎo)教師： 馬克新 2015 年 3 月 5 日 英文原文 1 Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader. Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology: Electrical discharge machining,Laser cutting,Electron beam welding. Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes. Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively. However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated. This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development. A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use. This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems. The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape. The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control. 2 Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet. Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing. 中文譯文 1.數(shù)字控制 先進(jìn)制造技術(shù)中的一個(gè)基本的概念是數(shù)字控制（NC）。在數(shù)控技術(shù)出現(xiàn)之前，所有的機(jī)床都是由人工操縱和控制的。在與人工控制的機(jī)床有關(guān)的很多局限性中，操作者的技能大概是最突出的問題。采用人工控制是，產(chǎn)品的質(zhì)量直接與操作者的技能有關(guān)。數(shù)字控制代表了從人工控制機(jī)床走出來的第一步。 數(shù)字控制意味著采用預(yù)先錄制的、存儲(chǔ)的符號(hào)指令來控制機(jī)床和其他制造系統(tǒng)。一個(gè)數(shù)控技師的工作不是去操縱機(jī)床，而是編寫能夠發(fā)出機(jī)床操縱指令的程序。對于一臺(tái)數(shù)控機(jī)床，其上必須安有一個(gè)被稱為閱讀機(jī)的界面裝置，用來接受和解譯出編程指令。 發(fā)展數(shù)控技術(shù)是為了克服人類操作者的局限性，而且它確實(shí)完成了這項(xiàng)工作。數(shù)字控制的機(jī)器比人工操縱的機(jī)器精度更高、生產(chǎn)出零件的一致性更好、生產(chǎn)速度更快、而且長期的工藝裝備成本更低。數(shù)控技術(shù)的發(fā)展導(dǎo)致了制造工藝中其他幾項(xiàng)新發(fā)明的產(chǎn)生： 電火花加工技術(shù)、激光切割、電子束焊接 數(shù)字控制還使得機(jī)床比它們采用有人工操的前輩們的用途更為廣泛。 一臺(tái)數(shù)控機(jī)床可以自動(dòng)生產(chǎn)很多類的零件，每一個(gè)零件都可以有不同的和復(fù)雜的加工過程。數(shù)控可以使生產(chǎn)廠家承擔(dān)那些對于采用人工控制的機(jī)床和工藝來說，在經(jīng)濟(jì)上是不劃算的產(chǎn)品生產(chǎn)任務(wù)。 同許多先進(jìn)技術(shù)一樣，數(shù)控誕生于麻省理工學(xué)院的實(shí)驗(yàn)室中。數(shù)控這個(gè)概念是50年代初在美國空軍的資助下提出來的。在其最初的價(jià)段，數(shù)控機(jī)床可以經(jīng)濟(jì)和有效地進(jìn)行直線切割。 然而，曲線軌跡成為機(jī)床加工的一個(gè)問題，在編程時(shí)應(yīng)該采用一系列的水平與豎直的臺(tái)階來生成曲線。構(gòu)成臺(tái)階的每一個(gè)線段越短，曲線就越光滑。臺(tái)階中的每一個(gè)線段都必須經(jīng)過計(jì)算。 在這個(gè)問題促使下，于1959年誕生了自動(dòng)編程工具（APT）語言。這是一個(gè)專門適用于數(shù)控的編程語言，使用類似于英語的語句來定義零件的幾何形狀，描述切削刀具的形狀和規(guī)定必要的運(yùn)動(dòng)。APT語言的研究和發(fā)展是在數(shù)控技術(shù)進(jìn)一步發(fā)展過程中的一大進(jìn)步。最初的數(shù)控系統(tǒng)下今天應(yīng)用的數(shù)控系統(tǒng)是有很大差別的。在那時(shí)的機(jī)床中，只有硬線邏輯電路。指令程序?qū)懺诖┛准垘希ㄋ髞肀凰芰蠋〈?，采用帶閱讀機(jī)將寫在紙帶或磁帶上的指令給機(jī)器翻譯出來。所有這些共同構(gòu)成了機(jī)床數(shù)字控制方面的巨大進(jìn)步。然而，在數(shù)控發(fā)展的這個(gè)階段中還存在著許多問題。 一個(gè)主要問題是穿孔紙帶的易損壞性。在機(jī)械加工過程中，載有編程指令信息的紙帶斷裂和被撕壞是常見的事情。在機(jī)床上每加工一個(gè)零件，都需要將載有編程指令的紙帶放入閱讀機(jī)中重新運(yùn)行一次。因此，這個(gè)問題變得很嚴(yán)重。如果需要制造100個(gè)某種零件，則應(yīng)該將紙帶分別通過閱讀機(jī)100次。易損壞的紙帶顯然不能承受嚴(yán)配的車間環(huán)境和這種重復(fù)使用。 這就導(dǎo)致了一種專門的塑料磁帶的研制。在紙帶上通過采用一系列的小孔來載有編程指令，而在塑料帶上通過采用一系列的磁點(diǎn)瞇載有編程指令。塑料帶的強(qiáng)度比紙帶的強(qiáng)度要高很多，這就可以解決常見的撕壞和斷裂問題。然而，它仍然存在著兩個(gè)問題。 其中最重要的一個(gè)問題是，對輸入到帶中指令進(jìn)行修改是非常困難的，或者是根本不可能的。即使對指令程序進(jìn)行最微小的調(diào)整，也必須中斷加工，制作一條新帶。而且?guī)ㄟ^閱讀機(jī)的次數(shù)還必須與需要加工的零件的個(gè)數(shù)相同。幸運(yùn)的是，計(jì)算機(jī)技術(shù)的實(shí)際應(yīng)用很快解決了數(shù)控技術(shù)中與穿孔紙帶和塑料帶有關(guān)的問題。 在形成了直接數(shù)字控制（DNC）這個(gè)概念之后，可以不再采用紙帶或塑料帶作為編程指令的載體，這樣就解決了與之有關(guān)的問題。在直接數(shù)字控制中，幾臺(tái)機(jī)床通過數(shù)據(jù)傳輸線路聯(lián)接到一臺(tái)主計(jì)算機(jī)上。操縱這些機(jī)床所需要的程序都存儲(chǔ)在這臺(tái)主計(jì)算機(jī)中。當(dāng)需要時(shí)，通過數(shù)據(jù)傳輸線路提供給每臺(tái)機(jī)床。直接數(shù)字控制是在穿孔紙帶和塑料帶基礎(chǔ)上的一大進(jìn)步。然而，它敢有著同其他信賴于主計(jì)算機(jī)技術(shù)一樣的局限性。當(dāng)主計(jì)算機(jī)出現(xiàn)故障時(shí)，由其控制的所有機(jī)床都將停止工作。這個(gè)問題促使了計(jì)算機(jī)數(shù)字控制技術(shù)的產(chǎn)生。 微處理器的發(fā)展為可編程邏輯控制器和微型計(jì)算機(jī)的發(fā)展做好了準(zhǔn)備。這兩種技術(shù)為計(jì)算機(jī)數(shù)控（CNC）的發(fā)打下了基礎(chǔ)。采用CNC技術(shù)后，每臺(tái)機(jī)床上都有一個(gè)可編程邏輯控制器或者微機(jī)對其進(jìn)行數(shù)字控制。這可以使得程序被輸入和存儲(chǔ)在每臺(tái)機(jī)床內(nèi)部。它還可以在機(jī)床以外編制程序，并將其下載到每臺(tái)機(jī)床中。計(jì)算機(jī)數(shù)控解決了主計(jì)算機(jī)發(fā)生故障所帶來的問題，但是它產(chǎn)生了另一個(gè)被稱為數(shù)據(jù)管理的問題。同一個(gè)程序可能要分別裝入十個(gè)相互之間沒有通訊聯(lián)系的微機(jī)中。這個(gè)問題目前正在解決之中，它是通過采用局部區(qū)域網(wǎng)絡(luò)將各個(gè)微機(jī)聯(lián)接起來，以得于更好地進(jìn)行數(shù)據(jù)管理。 2.車床 車床主要是為了進(jìn)行車外圓、車端面和鏜孔等項(xiàng)工作而設(shè)計(jì)的機(jī)床。車削很少在其他種類的機(jī)床上進(jìn)行，而且任何一種其他機(jī)床都不能像車床那樣方便地進(jìn)行車削加工。由于車床還可以用來鉆孔和鉸孔，車床的多功能性可以使工件在一次安裝中完成幾種加工。因此，在生產(chǎn)中使用的各種車床比任何其他種類的機(jī)床都多。 車床的基本部件有：床身、主軸箱組件、尾座組件、溜板組件、絲杠和光杠。 床身是車床的基礎(chǔ)件。它能常是由經(jīng)過充分正火或時(shí)效處理的灰鑄鐵或者球墨鐵制成。它是一個(gè)堅(jiān)固的剛性框架，所有其他基本部件都安裝在床身上。通常在床身上有內(nèi)外兩組平行的導(dǎo)軌。有些制造廠對全部四條導(dǎo)軌都采用導(dǎo)軌尖朝上的三角形導(dǎo)軌（即山形導(dǎo)軌），而有的制造廠則在一組中或者兩組中都采用一個(gè)三角形導(dǎo)軌和一個(gè)矩形導(dǎo)軌。導(dǎo)軌要經(jīng)過精密加工以保證其直線度精度。為了抵抗磨損和擦傷，大多數(shù)現(xiàn)代機(jī)床的導(dǎo)軌是經(jīng)過表面淬硬的，但是在操作時(shí)還應(yīng)該小心，以避免損傷導(dǎo)軌。導(dǎo)軌上的任何誤差，常常意味著整個(gè)機(jī)床的精度遭到破壞。 主軸箱安裝在內(nèi)側(cè)導(dǎo)軌的固定位置上，一般在床身的左端。它提供動(dòng)力，并可使工件在各種速度下回轉(zhuǎn)。它基本上由一個(gè)安裝在精密軸承中的空心主軸和一系列變速齒輪(類似于卡車變速箱)所組成。通過變速齒輪，主軸可以在許多種轉(zhuǎn)速下旋轉(zhuǎn)。大多數(shù)車床有8~12種轉(zhuǎn)速，一般按等比級(jí)數(shù)排列。而且在現(xiàn)代機(jī)床上只需扳動(dòng)2~4個(gè)手柄，就能得到全部轉(zhuǎn)速。一種正在不斷增長的趨勢是通過電氣的或者機(jī)械的裝置進(jìn)行無級(jí)變速。 由于機(jī)床的精度在很大程度上取決于主軸，因此，主軸的結(jié)構(gòu)尺寸較大，通常安裝在預(yù)緊后的重型圓錐滾子軸承或球軸承中。主軸中有一個(gè)貫穿全長的通孔，長棒料可以通過該孔送料。主軸孔的大小是車床的一個(gè)重要尺寸，因此當(dāng)工件必須通過主軸孔供料時(shí)，它確定了能夠加工的棒料毛坯的最大尺寸。 尾座組件主要由三部分組成。底板與床身的內(nèi)側(cè)導(dǎo)軌配合，并可以在導(dǎo)軌上作縱向移動(dòng)。底板上有一個(gè)可以使整個(gè)尾座組件夾緊在任意位置上的裝置。尾座體安裝在底板上，可以沿某種類型的鍵槽在底板上橫向移動(dòng)，使尾座能與主軸箱中的主軸對正。尾座的第三個(gè)組成部分是尾座套筒。它是一個(gè)直徑通常大約在51~76mm（2~3英寸）之間的鋼制空心圓柱體。通過手輪和螺桿，尾座套筒可以在尾座體中縱向移入和移出幾個(gè)英寸。 車床的規(guī)格用兩個(gè)尺寸表示。第一個(gè)稱為車床的床面上最大加工直徑。這是在車床上能夠旋轉(zhuǎn)的工件的最大直徑。它大約是兩頂尖連線與導(dǎo)軌上最近點(diǎn)之間距離的兩倍。第二個(gè)規(guī)格尺寸是兩頂尖之間的最大距離。車床床面上最大加工直徑表示在車床上能夠車削的最大工件直徑，而兩頂尖之間的最大距離則表示在兩個(gè)頂尖之間能夠安裝的工件的最大長度。 普通車床是生產(chǎn)中最經(jīng)常使用的車床種類。它們是具有前面所敘的所有那些部件的重載機(jī)床，并且除了小刀架之外，全部刀具的運(yùn)動(dòng)都有機(jī)動(dòng)進(jìn)給。它們的規(guī)格通常是：車床床面上最大加工直徑為305~610mm（12~24英寸）；但是，床面上最大加工直徑達(dá)到1270mm（50英寸）和兩頂尖之間距離達(dá)到3658mm的車床也并不少見。這些車床大部分都有切屑盤和一個(gè)安裝在內(nèi)部的冷卻液循環(huán)系統(tǒng)。小型的普通車床—車床床面最大加工直徑一般不超過330mm（13英寸）--被設(shè)計(jì)成臺(tái)式車床，其床身安裝在工作臺(tái)或柜子上。 雖然普通車床有很多用途，是很有用的機(jī)床，但是更換和調(diào)整刀具以及測量工件花費(fèi)很多時(shí)間，所以它們不適合在大量生產(chǎn)中應(yīng)用。通常，它們的實(shí)際加工時(shí)間少于其總加工時(shí)間的30%。此外，需要技術(shù)熟練的工人來操作普通車床，這種工人的工資高而且很難雇到。然而，操作工人的大部分時(shí)間卻花費(fèi)在簡單的重復(fù)調(diào)整和觀察切屑過程上。因此，為了減少或者完全不雇用這類熟練工人，六角車床、螺紋加工車床和其他類型的半自動(dòng)和自動(dòng)車床已經(jīng)很好地研制出來，并已經(jīng)在生產(chǎn)中得到廣泛應(yīng)用。