機(jī)械工程專業(yè)英語_施平_沒翻譯課文補(bǔ)充

1、4、工程機(jī)械概述 As we look around us we see a world full of “things”: machines, devices, tools; things that we have designed, built, and used; things made of wood, metals, ceramics, and plastics. We know from experience that some things are better than others; they last longer, cost less, are quieter, look

2、 better, or are easier to use. 正如我們環(huán)顧四周我們看到世界的“東西”機(jī)器全設(shè)備工具;事情我們已經(jīng)設(shè)計建造和使用;木材金屬瓷制成的東西和塑料。我們從經(jīng)驗知道有些事情是比別人做得更好他們?nèi)ツ旮L成本更低更安靜看起來更好或者更容易使用。理想的情況. Ideally, however, every such item has been designed according to some set of “functional requirements” as perceived by the designers that is, it has been designed

3、 so as to answer the question, “Exactly what function should it perform?” In the world of engineering, the major function frequently is to support some type of loading due to weight, inertia, pressure, etc. 但是每個這樣的項目已按設(shè)計一些“功能要求”由設(shè)計者認(rèn)為也就是說它的設(shè)計以回答這個問題“究竟是什么職能應(yīng)是執(zhí)行在工程世界”頻繁的主要功能是如此的支持由于一些裝載重量慣性壓力式 From t

4、he beams in our homes to the wings of an airplane, there must be an appropriate melding of materials, dimensions, and fastenings to produce structures that will perform their functions reliably for a reasonable cost over a reasonable lifetime. 從我們家中的光束飛機(jī)的一個機(jī)翼等必須對產(chǎn)品的材料尺寸適當(dāng)?shù)娜诤虾途o固件生產(chǎn)結(jié)構(gòu)將執(zhí)行一個較合理的成本合理的一生中

5、其職能可靠。 In practice, engineering mechanics methods are used in two quite different ways: (1) The development of any new device requires an interactive, iterative consideration of form, size, materials, loads, durability, safety, and cost. (2) When a device fails (unexpectedly) it is often necessary t

6、o carry out a study to pinpoint the cause of failure and to identify potential corrective measures. Our best designs often evolve through a successive elimination of weak points. 在實踐中工程力學(xué)方法用于在兩個完全不同的方式 1.任何新設(shè)備的發(fā)展需要一個互動形式尺寸材料載荷耐久性安全性和cost. 2.迭代審議。當(dāng)一個設(shè)備出現(xiàn)故障往往是要進(jìn)行一項研究以查明故障原因并找出潛在的糾正措施。我們最優(yōu)秀的設(shè)計往往演變的薄弱環(huán)節(jié)

7、通過逐步消除。 To many engineers, both of the above processes can prove to be absolutely fascinating and enjoyable, not to mention (at times) lucrative. 對許多工程師上述過程都可以被證明是絕對精彩和愉快的更不用提有利可圖。 In any “real” problem there is never sufficient good, useful information; we seldom know the actual loads and operating

8、 conditions with any precision, and the analyses are seldom exact. While our mathematics may be precise, the overall analysis is generally only approximate, and different skilled people can obtain different solutions. In the study of engineering mechanics, most of the problems will be sufficiently “

9、idealized” to permit unique solutions, but it should be clear that the “real world” is far less idealized, and that you usually will have to perform some idealization in order to obtain a solution. 在任何“真正”的問題從來就沒有足夠好的有用的信息我們很少知道實際的載荷和精確操作的任何條件準(zhǔn)確的分析很少。雖然我們可以精確的數(shù)學(xué)綜合分析一般只是近似不同技能的人可以得到不同的解決方案。在工程力學(xué)研究中大多

10、數(shù)問題都將得到充分的“理想化”允許獨特的解決方案但應(yīng)該清楚“現(xiàn)實世界”遠(yuǎn)不如理想而且你通常會在命令必須執(zhí)行一些理想化獲得一個解決方案。 The technical areas we will consider are frequently called “statics” and “strength of materials,” “statics” referring to the study of forces acting on stationary devices, and “strength of materials” referring to the effects of those

11、 forces on the structure (deformations, load limits, etc.). 在技術(shù)領(lǐng)域中我們將考慮的是通常稱為“靜”與“材料力學(xué)”“靜”指的是對固定設(shè)備作用力學(xué)風(fēng)和“材料力學(xué)”指的是這些部隊在結(jié)構(gòu)上的影響。 While a great many devices are not, in fact, static, the methods developed here are perfectly applicable to dynamic situations if the extra loadings associated with the dynam

12、ics are taken into account (we shall briefly mention how this is done). static 盡管許多設(shè)備都沒有事實上靜態(tài)的這里開發(fā)的方法是完全適用于動態(tài)的情況如果與動態(tài)相關(guān)聯(lián)的額外負(fù)荷考慮。. Whenever the dynamic forces are small relative to the static loadings, the system is usually considered to be 每當(dāng)動態(tài)勢力相對較小的靜態(tài)負(fù)荷系統(tǒng)通常被認(rèn)為是靜態(tài)的。 In engineering mechanics, we wil

13、l appreciate the various types of approximations that are inherent in any real problem: Primarily, we will be discussing things which are in “equilibrium,” i.e., not accelerating. However, if we look closely enough, everything is accelerating. We will consider many structural members to be “weightle

14、ss” but they never are. We will deal with forces that act at a “point” but all forces act over an area. We will consider some parts to be “rigid” but all bodies will deform under load. 在工程力學(xué)我們贊賞逼近了在任何類型的固有的各種現(xiàn)實問題 首先我們將要討論的事情這是在“均衡”即沒有加速。但是如果我們仔細(xì)觀察的話一切都正在加速。我們會考慮很多構(gòu)件是“失重”但是他們從來沒有的。我們將按 照部隊的這種行為在一個“點”

15、但所有力量在一個區(qū)域的行為。我們會考慮的某些部分“剛性”但所有機(jī)構(gòu)將在負(fù)荷下變形。 We will make many assumptions that clearly are false. But these assumptions should always render the problem easier, more tractable. You will discover that the goal is to make as many simplifying assumptions as possible without seriously degrading the result

16、. 我們會作出這樣的假設(shè)顯然是錯誤的。但是這些假設(shè)應(yīng)始終呈現(xiàn)的問題更容易更容易處理。你會發(fā)現(xiàn)他們的目標(biāo)是使盡可能多的簡化假設(shè)沒有嚴(yán)重退化的結(jié)果。 Generally there is no clear method to determine how completely, or how precisely, to treat a problem: If our analysis is too simple, we may not get a pertinent answer; if our analysis is too detailed, we may not be able to obta

17、in any answer. It is usually preferable to start with a relatively simple analysis and then add more detail as required to obtain a practical solution. 一般來說沒有明確的方法來確定如何徹底或如何精確地說對待一個問題如果我們的分析過于簡單我們可能無法獲得相關(guān)的答案如果我們的分析過于詳細(xì)我們可能無法獲得任何答案。它通常是最好先從相對簡單的分析然后添加更多的細(xì)節(jié)因為需要得到實際的解決辦法。 During the past two decades, t

18、here has been a tremendous growth in the availability of computerized methods for solving problems that previously were beyond solution because the time required to solve them would have been prohibitive. At the same time the cost of computer capability and use has decreased by orders of magnitude.

19、We are experiencing an influx of “personal computers” on campus, in the home, and in business. 在過去的二十年來一直在為解決以往無法解決的問題進(jìn)行電腦化方法的途徑巨大增長因為所需的時間來解決這些問題將被禁止。在同一時間計算機(jī)能力和使用成本下降了幾個數(shù)量級。我們正經(jīng)歷一個“個人電腦”校園涌入在家里和商業(yè)活動中。 26、車床 The general characteristics of the machine tools used in cutting operations are reviewed in

20、 this text. The equipment can be classified in different categories depending on their function and the accessories involved. The major categories are described below. 在切割操作中使用的機(jī)床的一般特征在這篇文章進(jìn)行闡述。依據(jù)功能和所包含的配件設(shè)備可分為不同類別。主要類別如下所述。 Lathes Lathes are generally considered to be the oldest machine tools and w

21、ere developed in the 1750s.The basic operations carried out on a lathe are turning, boring, and facing.車床 車床通常被認(rèn)為是最古老的機(jī)床并在1750s產(chǎn)生.車床上進(jìn)行基本操作有車削鏜和端面車削。 The basic components of the most common lathe( engine lathe ) are the bed, headstock, tailstock, and carriage. One end of the workpiece is clamped in

22、a chuck that is mounted on the spindle, the spindle rotates in the headstock. The other end of the workpiece is supported by the tailstock. The headstock contains the drive gears for the spindle speeds, and through suitable gearing and the feed rod, drives the carriage and cross slide assembly. The

23、carriage provides motion parallel to the axis of rotation, and the cross slide provides motion normal to it. A cutting tool, attached to a tool post and to the carriage, removes material by traveling along the bed. The cutting operation is performed at a certain desired peripheral speed of the workp

24、iece, feed rate, and depth of cut 最常見的車床普通車床的基本組成部分是床身床頭尾座和.托架。工件的一端是被一個安裝在主軸的夾頭夾緊主軸在床頭旋轉(zhuǎn)。工件的另一端是由尾座支撐。床頭包含主軸轉(zhuǎn)速傳動齒輪并通過適當(dāng)?shù)凝X輪和進(jìn)給桿驅(qū)動車架使滑動裝配滑動。托架提供運(yùn)動平行旋轉(zhuǎn)軸橫滑板提供了正常的運(yùn)動。切削刀具連接到一個刀架和托架沿床消除材料。切割操作是按工件所需的一定的外設(shè)速度進(jìn)給速度切削深度運(yùn)行。 A further development is the automatic lathe. The movements and controls are actuated b

25、y various mechanical means, such as cams and numerical and computer control, thus reducing labor or requiring less skilled labor. 進(jìn)一步發(fā)展的是自動車床。通過各種機(jī)械手段運(yùn)動和控制更加精確。如凸輪和數(shù)控和計算機(jī)控制從而減輕了工人的勞動或要求不太熟練的勞動力。 Turret lathes (developed in the 1850s)carry out multiple cutting operations, such as turning, boring, dri

26、lling, thread cutting, and facing. Various cutting tools, usually up to six are installed on a turret. The operation is quite versatile. It may be operated by hand or automatically and, once set up properly, it does not require skilled labor. There are a great variety of turret lathes available for

27、different purposes. 轉(zhuǎn)塔車床在19世紀(jì)50年代開發(fā)的能夠進(jìn)行了多種切割操作如車削鏜鉆線切割端面車削。各種切削工具通常在最多六個炮塔上安裝。操作相當(dāng)靈活。它可能是手工操作或自動一旦正確安裝它并不需要熟練的勞動力。有種類繁多的炮塔車床可用于不同的目的 Screw machines (the first screw lathe was developed in the 1770s)are designed for high production rate machining of screws and similar parts. All the operations are p

28、erformed automatically with tools attached to a special turret. The bar stock is fed automatically after each screw has been machined to a finished product. These machines may be equipped with single or multiple spindles to reduce the cycle time per piece. 螺桿機(jī)在18世紀(jì)70年代開發(fā)了第一個螺絲車床是專為高產(chǎn)率自動化生產(chǎn)螺釘 和類似部件的設(shè)

29、計的。所有的操作都由連接到一個特殊的炮塔的工具自動執(zhí)行。每個螺絲加工成成品后棒料自動送入。這些機(jī)器可能會配有單個或多個主軸 Milling Machines These are among the most versatile and useful machine tools because they are capable of performing a variety of cutting operations. There is a large selection of milling machines (developed in the 1860s)available with num

30、erous features. The basic types are outlined below.Knee-and-column type milling machines are the most common and are used for general-purpose machining. The spindle, to which the milling cutter is attached, may be horizontal (for slab milling), or vertical (for face milling). 銑床銑床是最通用和最有用的工具機(jī)因為它們能夠執(zhí)

31、行各種切割操作。有大量的提供眾多特性的銑床可供選擇在19世紀(jì)60年代開發(fā)的?；绢愋透攀鋈缦?。 升降臺式銑床是最常見的用于一般用途的加工。連接銑刀的主軸可水平板坯銑削或垂直面銑。 Bed-type milling machines have the table mounted on a bed (replacing the knee) and can move only in the longitudinal direction. These machines are simple and rigidly constructed and are used for high-quantity p

32、roduction. The spindles may be horizontal or vertical and can be of duplex or triplex types (that is, with two or three spindles for simultaneous machining of two or three surfaces on a part). Other types of milling machines are also available, such as the planer type for heavy work and machines for

33、 special purposes 床身式銑床上安裝一個平臺只可以在縱向方向移動。這些機(jī)器很簡單嚴(yán)格裝配并用于高量產(chǎn)。主軸可水平或垂直可以雙工或三工類型即有兩個或三個主軸同時加工兩個或三個部分表面。其他類型的銑削機(jī)也可用如用于繁重的工作的龍門式和特殊用途的機(jī)器。 Among accessories for milling machines, one of the most widely used is the universal dividing head. This is a fixture that rotates the workpiece to specified angles bet

34、ween individual machining steps. Typical uses are in milling parts with polygonal surfaces and in machining gear teeth. 銑床使用最廣泛的配件是通用的分度頭。這是一個夾具在各個加工步驟使工件旋轉(zhuǎn)到指定角度。典型的用途是加工銑削有多邊形表面的零件和加工齒輪齒。 Planers and Shapers These machine tools are generally used for machining large flat surfaces although other sha

35、pes, such as grooves, can also be machined. In a planer, the workpiece travels under the cross-rail equipped with cutting tools, whereas in a shaper the tool travels and the workpiece is stationary 龍門刨床和牛頭刨床這些機(jī)床一般用于加工大平面 雖然其他形狀如凹槽也可以加工。在龍門刨床工件上在裝有刀具的下軌移動而在牛頭刨床工具移動和工件是固定的。 Because of the size of the

36、workpieces involved, planers are among the largest machine tools. Shapers may be horizontal or vertical and are also used for machining notches and keyways 由于所涉與的工件的大小龍門刨床是位于最大的機(jī)床之列。刨邊機(jī)可水平或垂直也用于加工凹槽和鍵槽。 Broaching Machines These machines push or pull broaches, either horizontally or vertically, to ge

37、nerate various external or internal surfaces. They are of relatively simple construction and are actuated hydraulically and have only linear motion of the broach. Because of the great variety of shapes and parts involved, broaching machines are manufactured in a wide range of designs and sizes. 拉床 這

38、些機(jī)器推或拉拉刀水平或垂直從而加工各種部或外部的表面。他們的構(gòu)造相對簡單液壓驅(qū)動可實現(xiàn)拉刀只有直線運(yùn)動。由于涉與的形狀和部分種類繁多拉床被制造成各式的設(shè)計和尺寸。 Drilling Machines These machines are used for drilling holes, tapping, counterboring, reaming, and other general-purpose boring operations. They are usually vertical, the most common one being a drill press. Drilling m

39、achines are manufactured in a wide variety of sizes, from simple bench type units to radial drills and large production machines with multiple spindles. 鉆孔機(jī)這些機(jī)器用于鉆孔攻絲锪孔鉸孔和其他通用的鏜操作。它們通常是垂直的最常見的一種是鉆床。鉆床制造成種類繁多的尺寸從簡單的板凳類型單元到搖臂鉆床和有多個主軸的大型生產(chǎn)設(shè)備。 46課 Computer-aided designCADinvolves the use of computers to

40、 create design drawings and product models. Computer-aided design is usually associated with interactive computer graphicsknown as a CAD system. 計算機(jī)輔助設(shè)計(CAD)涉與到電腦的使用來創(chuàng)建設(shè)計圖紙和產(chǎn)品模型。計算機(jī)輔助設(shè)計通常是與交互式計算機(jī)圖形學(xué)(稱為CAD系統(tǒng))。 Computer-aided design systems are powerful tools and are used in the mechanical design and

41、geometric modeling of products and components 計算機(jī)輔助設(shè)計系統(tǒng)是強(qiáng)大的工具,用于產(chǎn)品的機(jī)械設(shè)計和幾何建模和組件 In CADthe drawing board is replaced by electronic input and output devices. When using a CAD systemthe designer can conceptualize the object to be designed more easily on the Graphics screen and can consider alternative

42、designs or modify a particular design quickly to meet the necessary design requirements or changes. 在CAD圖紙被電子輸入和輸出設(shè)備。當(dāng)使用CAD系統(tǒng)中,設(shè)計人員可以概念化設(shè)計的對象更容易在圖形屏幕上,可以考慮替代設(shè)計或修改一個特定設(shè)計迅速滿足必要的設(shè)計要求或更改。 The designer can then subject the design to a variety of engineering analyses and can identify potential problems su

43、ch as an excessive load or deflection. The speed and accuracy of such analyses far surpass what is available from traditional methods. 設(shè)計師可以設(shè)計各種各樣的工程分析和可以識別潛在的問題(如過度負(fù)荷或偏轉(zhuǎn))。這種分析的速度和準(zhǔn)確度遠(yuǎn)遠(yuǎn)超過可以從傳統(tǒng)的方法是什么。 Draft productivity rises dramatically. When something is drawn onceit never has to be drawn again. 草

44、案生產(chǎn)率大幅上升。當(dāng)有了一次,它從來沒有再畫。 it can be retrieved from a library ,and can be duplicated, stretched, sized, and changed in many ways without having to be redrawn。Cut and paste techniques are used as labor-saving aids. 它可以從庫檢索,可以復(fù)制,拉伸,大小,改變在許多方面不用redrawn.Cut粘貼技術(shù)用作省力艾滋病。 CAD makes possible multiview 2D drawi

45、ngs and the drawings can be reproduced in different levels of reduction and enlargement. CAD使可能的多視圖2 d圖紙,圖紙可以復(fù)制在不同程度的減少和擴(kuò)大。 It gives the mechanical engineer the ability to magnify even the smallest of components to ascertain if assembled components fit properly. 它讓機(jī)械工程師的能力放大甚至最小的組件來確定如果組裝組件配合得當(dāng)。 Par

46、ts with different characteristicssuch as movable or stationary can be assigned different colors on the display. 部分具有不同特點,如移動或靜止不動的,可以指定不同的顏色顯示。 Designers have even more freedom with the advent of 3-D parts and manipulate them in endless variations to achieve the desired results. 設(shè)計師有更多自由隨著3 d部分和操縱他們

47、無窮無盡的變化來獲得期望的結(jié)果。 Through finite element analysis stresses can be applied to be a computer model and the results graphically displayedgiving the designer quick feedback on any inherent problems in a design before the creation of a physical prototype. 通過有限元分析,壓力可以被應(yīng)用到一個計算機(jī)模型,結(jié)果以圖形方式顯示出來,給設(shè)計師提供快速反饋任何固有

48、的問題在設(shè)計物理原型的創(chuàng)建。 In addition to the designs geometric and dimensional featuresother information such as a list of materialsspecification and manufacturing instructionsis stored in the CAD database. Using such information ,the designer can then analyze the economics of alternative designs. 除了設(shè)計的幾何和空間特性

49、,其他信息(如材料的清單,規(guī),和生產(chǎn)指令)存儲在CAD數(shù)據(jù)庫。使用這些信息,設(shè)計師可以分析替代的經(jīng)濟(jì)設(shè)計。 Computer-aided manufacturing(CAM) involves the uses of computers and computer technology to assist in all the phases of manufacturing a productincluding process and production planningmachiningschedulingmanagement and quality control. Computer-ai

50、ded design and computer-aided manufacturing are often combined into CAD/CAM systems. 計算機(jī)輔助制造(CAM)涉與計算機(jī)和計算機(jī)技術(shù)的使用,協(xié)助生產(chǎn)一個產(chǎn)品的所有階段,包括過程和生產(chǎn)計劃、加工、調(diào)度、管理和質(zhì)量控制。計算機(jī)輔助設(shè)計和計算機(jī)輔助制造通常結(jié)合到CAD / CAM系統(tǒng)。 This combination allow the transfer of information from the design stage into the stage of of planning for the manufa

51、cture of a productwithout the need to reenter the data on part geometry manually. 這種組合允許轉(zhuǎn)讓信息從設(shè)計階段的階段,規(guī)劃產(chǎn)品的生產(chǎn),而不需要手動重新輸入數(shù)據(jù)部分幾何。 The database developed during CAD is stored then it is processed furtherby CAMinto the necessary data and instructions for operating and controlling production machinerymate

52、rial-handling equipmentand automated testing and inspection for product quality. 在CAD開發(fā)的數(shù)據(jù)庫存儲;然后進(jìn)一步處理,通過凸輪,到所需的數(shù)據(jù)和指令操作和控制生產(chǎn)機(jī)械、設(shè)備來源,自動化測試和檢驗產(chǎn)品質(zhì)量。 In machining operationsan important feature of CAD/CAM is its capability to describe the tool path for various operationssuch as NC turningmillingand drill

53、ing. 在加工操作中,CAD / CAM的一個重要特性是其能力來描述刀具軌跡的各種操作,如數(shù)控車削、銑削和鉆孔。 The instructions programsare computer generatedand they can be modified by the programmer to optimize the tool path . 計算機(jī)生成的指令(程序),他們可以由程序員修改優(yōu)化刀具軌跡。 The engineer or technician can then display and visually check the tool path for possible too

54、l collisions with fixtures or other interferences. The tool path can be modified at any timeto accommodate other part shapes to be machined. 工程師或技術(shù)員可以顯示和視覺檢查刀具軌跡的可能的工具與設(shè)備碰撞或其他干擾。工具路徑隨時可以修改,以適應(yīng)其他部分形狀加工。 Some typical applications of CAD/CAM areaprogramming for NCCNCand industrial robotsbdesign of tool

55、s and fixtures and EDM electodescquality control and inspectionfor instancecoordinate-measuring machines programmed on a CAD/CAM workstationdprocess planning and scheduling andeplant layout. 一些典型的CAD / CAM的應(yīng)用是:(a)為數(shù)控編程,數(shù)控,和工業(yè)機(jī)器人;(b)設(shè)計的工具和夾具和EDM electodes;(c)質(zhì)量控制和檢查,例如,坐標(biāo)測量機(jī)CAD / CAM工作站程序;(d)工藝規(guī)劃和調(diào)度;

56、(e)工廠的布局。 The emergence of CAD/CAM has had a major impact on manufacturingby standardizing product development and by reducing design efforttryoutand prototype workit has made possible significantly reduced costs and improved productivity. CAD / CAM的出現(xiàn)已經(jīng)對生產(chǎn)產(chǎn)生重大影響,通過標(biāo)準(zhǔn)化產(chǎn)品開發(fā)和減少設(shè)計工作,調(diào)試,和原型工作;它可能顯著降低成本和

57、提高生產(chǎn)力。 The two-engine Boeing 777 passenger airplanefor example, was designed completed by computerpaperless design . The plane is constructed directly from the CAD/CAM software developedan enhanced CATIA systemand no prototypes or mockups were built such as were required for previous models. 雙引擎的波音777客機(jī),例如,設(shè)計完成的計算機(jī)(無紙化設(shè)計)。飛機(jī)構(gòu)造直接從開發(fā)的CAD / CAM軟件(一個增強(qiáng)的CATIA系統(tǒng))和任何原型和模型建立,如需要以前的模型。50課 Today, compute