机电专业英语第2版2Unit 2Machine Elements机械零件-席东河-机电专业英语

1、LOGO机械零件 徐存善主编What does “clutch” mean (radio)？“Clutch”是什么意思(单选)：提交 徐存善主编 徐存善主编 徐存善主编 However simple, any machine is a combination of individual components generally referred to as machine elements or parts. Thus, if a machine is completely dismantled, a collection of simple parts remains such as nut

2、s, bolts, springs gears, cams and shafts the building block of all machinery1. A machine element is, therefore, a single unit designed to perform a specific function and capable of combining with other elements. Sometimes certain elements are associated in pairs2, such as nuts and bolts or keys and

3、shafts. In other instance, a group of elements is combined to form a subassembly, such as bearings, couplings, and clutches. 徐存善主编 The most common example of a machine element is a gear, which, fundamentally, is a combination of the wheel and the lever to form a toothed wheel. The rotation of this g

4、ear on a hub or shaft drives other gears that may rotate faster or slower, depending upon the number of teeth on the basic wheels. 徐存善主编Other fundamental machine elements have evolved from wheel and lever. A wheel must have a shaft on which it may rotate. The wheel is fastened to the shafts with cou

5、plings. The shaft must rest in bearings, may be turned by a pulley with a belt or a chain connecting it to a pulley on a second shaft. The supporting structure may be assembled with bolts or rivets or by welding4. Proper application of these machine elements depends upon knowledge of the force on th

6、e structure and the strength of the materials employed. 徐存善主编 The individual reliability of machine elements becomes the basis for estimating the overall life expectancy of a complete machine. Many machine elements are thoroughly standardized. Testing and practical experience have established the mo

7、st suitable dimensions for common structural and mechanical parts. Through standardization, uniformity of practice and resulting economics are obtained. Not all machine parts in use are standardized, however. In the automotive industry only fasteners, bearings, bushings, chains, and belts are standa

8、rdized. Crankshafts and connecting rods are not standardized. 徐存善主编combination kCmbi5neiFEn n. 组合，结合individual indi5vidjuEl adj. 单独的，各个的，个别的，特殊的component kEm5pEunEnt n. 元件，构件，部件dismantle dis5mAntl vt. 分解（机器），拆开，拆卸assemble E5sembl v. 安装，装配，组合；集合，集中 n 组件nut nQt n. 螺母；难对付的人；难解的问题；坚果 vi. 采坚果bolt bEult n

9、. 螺栓；（门、窗等的）插销gear giE n. 仪器，装置；传动装置，齿轮cam kAm n. 凸轮，偏心轮；样板，靠模，仿形板lever 5li:vE n. 杠杆，控制杆，操作杆shaft FB:ft n. 柱身；连杆；传动轴，旋转轴；轴 徐存善主编machinery mE5Fi:nEri n. 机器 (总称)associate E5sEuFieit v. 联合，结合，参加，连带key ki: n. 键，电键，开关；楔，销；钥匙subassembly 7sQbE5sembli n. 组合件，部件，机组coupling 5kQpliN n. 联轴节，联轴器；联结器，联合器clutch kl

10、QtF n. 离合器，联轴器；夹紧装置fundamentally fQndE5mentli adv.（从）根本上hub hQb n. (轮) 毂；中心；木片rotate rEu5teit n. (使某物) 旋转或转动evolve i5vClv v. 进化，演变；开展，发展，展开pulley 5puli n. 滑轮（组）；滑车；皮带轮 徐存善主编rivet 5rivit n. 铆钉 v 铆接，铆weld weld v. & n. 焊接，熔焊reliability rilBiE5biliti n. 可靠性，安全性，准确性thoroughly 5WQrEli adv. 完全地，充分地，彻底地

11、standardize 5stAndEdBiz vt. 标准化，统一标准；标定，校准establish is5tAbliF vt. 确定，制定；建立，创办，产生；使固定dimension di5menFEn n. 尺寸，尺度；范围，方面bushing 5buFiN n. 衬套；轴衬；轴瓦；电（绝缘）套管uniformity 7mju:ni5fC:miti n. 均匀性，一致性automotive C:tE5mEutiv adj. 自动的，自动车的crank krANk n. 曲轴 refer to as 称为，叫做；当做；参考作为；所说的；提到的 Language points 徐存善主编1.

12、 Thus, if a machine is completely dismantled, a collection of simple parts remains such as nuts, bolts, springs gears, cams and shafts the building block of all machinery. 译文：因此，如果把机床完全拆开，就可以得到像螺母、螺栓、弹簧、齿轮、凸轮及轴等简单零件所有机器的标准元件。 Language points 徐存善主编2. Sometimes certain elements are associated in pairs

13、.译文：某些特定的元件必须成对地工作。说明：be associated with：与有关；涉及 又如：I associated with him in business. 我与他和伙经商。These concerns may be associated with strong feelings such as anger or shame. 这些忧虑很可能与恼火、羞愧之类的强烈情绪有关联。 Language points 徐存善主编3. The most common example of a machine is a gear, which, fundamentally, is a comb

14、ination of the wheel and the lever to form a toothed wheel. 译文：机器零件中最常用的是齿轮，它实际上是由轮子和杆组成的带有齿的轮子。说明：Which 引导非限定性定语从句，修饰gear，不定式to form a toothed wheel作结果状语。Language points 徐存善主编4The supporting structure may be assembled with bolts or rivets or by welding.译文：支撑结构可由螺栓或铆钉或通过焊接固定在一起。说明：句中with bolts or ri

15、vets or by welding 作方式状语，be assembled with 用 安装，又如：The bookcase can easily be assembled with a screwdriver. 这书柜用一把螺丝刀就可以很容易地安装起来。 Exercises 徐存善主编I. Answer the following questions. What is referred to as a machine element? Which is the most common machine element?2. What are other fundamental machine

16、 elements?3. Which machine elements are standardized in the automotive industry? A machine element is a single unit designed to perform a specific function and capable of combining with other elements. The most common machine element is a gear. Other fundamental machine elements have evolved from wh

17、eel and lever. In the automotive industry only fasteners, bearings, bushings, chains, and belts are standardized. Exercises 徐存善主编II. Place a “T” (true) or an “F”(false) beside the sentences according to the text. T1. Gears are used as building blocks for the construction of most devices, apparatus,

18、and machinery.2. A pair of gears with different numbers of teeth will rotate at different speeds.3. Spur gears and bevel gears are different in their applications because their shapes are different. 4. The most common machine element is the gear from which other fundamental machine elements have dev

19、eloped. 5. A coupling is a machine element, which joins two shafts. 6. All machine parts have been developed into standardized designs. FTTTFExercises 徐存善主编 Translate the following sentences into ChineseThe most common machine element is the gear, which combines the feature of the wheel and the leve

20、r to form a toothed wheel. 2. The hardness of a gear determines its ability to resist wear.最常见的机械零件是齿轮，实际上是由轮子和杆组成的跌有齿的轮子。 齿轮的坚硬性决定了它的耐磨能力。 Exercises 徐存善主编 Translate the following sentences into Chinese3. Manufacturing engineers have centered their efforts on the development of standardized elements

21、.4.These parts are produced in large quantities with a high degree of perfection at reduced cost.制造业的工程师们集中精力，研制标准化的零件。 这些零件是以大批量、高规格和降低成本的条件下生产的。 徐存善主编英汉两种语言都有一词多类、一词多义的现象。一词多类是指一个词往往属于多个词类，具有几种不同的意义。如display一词，既可做名词“显示（器）”，又可以作形容词“展览的、陈列用的”，还可做动词“显示、表现”等意思。一词多义是说同一个词类中，往往有几个不同的词义。如power 一词，做名词时，其汉

22、语意思为“电力、功率、次方”等。在英汉翻译过程中，我们在弄清句子结构后就要善于选择和确定句子中关键词的意义。选择和确定词义通常从以下几个方面入手： 徐存善主编 选择某个词的词义时，首先要确定这个词在句中应属于哪一种词类，然选择某个词的词义时，首先要确定这个词在句中应属于哪一种词类，然后再进一步确定其词义。后再进一步确定其词义。下面以display为例： Here, you have the option of defining your own display variants. 这里，你有权定义你自己的显示变式。（display为名词） Often, it is best to displa

23、y materials on an information table. 通常，最好是把资料放在提供各类资讯的桌子上展示。(display为动词) The reverse side of a control panel, display panel, or the like; the side with the interconnecting wiring. （display为形容词） 控制面板、显示面板或类似的面板的反面，即带有互连接线的那一面。 徐存善主编 英语中同一个词，同一类词，在不同的场合，往往具有不同的含义。英语中同一个词，同一类词，在不同的场合，往往具有不同的含义。此时，必须根据

24、上下文的联系及整个句子的意思加以判断和翻译。此时，必须根据上下文的联系及整个句子的意思加以判断和翻译。例如as 这一连词：Wear resistance improves as cutting tool hardness increase. 当切削刀具的硬度越高时，其耐磨性就越好。（as引导时间状语从句）As heat makes things move, it is a form of energy.因为热能使物体运动，所以热是能的一种形式。（as引导原因状语从句） 徐存善主编 英译汉时，不仅必须根据上下文的联系理解词义，还需要根据词的搭英译汉时，不仅必须根据上下文的联系理解词义，还需要根据

25、词的搭配情况来理解词义。尤其在科技文献中，由于学科及专业不同，同一个词配情况来理解词义。尤其在科技文献中，由于学科及专业不同，同一个词在不同的专业中具有不同的意义。在不同的专业中具有不同的意义。比如： The fifth power of two is thirty-two. 二的五次方是三十二。（数学） With the development of electrical engineering, power can be transmitted over long distances. 随着电气工程的发展, 电力能输送得非常远。（电学） Friction can cause a loss

26、of power in every machine. 摩擦能引起每一台机器功率的损耗。（物理学） 徐存善主编 英语中有些名词的单数或复数表达的词义完全不同。英语中有些名词的单数或复数表达的词义完全不同。例如：名词名词 单数词义单数词义 复数词义复数词义facility 简易，灵巧 设施，工具charge 负荷，电荷 费用spirit 精神 酒精Although they lost, the team played with tremendous spirit.那队输是输了，但却表现了极其顽强的精神。Whisky, brandy, gin and rum are all spirits.威士忌、

27、白兰地、杜松子酒和朗姆酒都是烈酒。 徐存善主编 徐存善主编 Metal cutting tools must possess a variety of different properties in order to cut the different metals under varying conditions of severity.To meet these demands, tools have been produced from a variety of materials. Properties of Cutting ToolsThe most important proper

28、ties of cutting tools are hardness at high temperature, wear resistance, and impact strength. 金属切削刀具必须具有许多不同的性能，才能在各种恶劣条件下切削不同的金属。为满足这些要求，制作刀具需要用许多种材料。 切削刀具的性能切削刀具的性能 切削刀具最重要的性能是在高温下能保持的硬度以及耐磨损耐冲击和韧性好。 徐存善主编As a tool cuts, high heat is developed as a result of compression and friction at the cutting

29、 edge of the tool. All metal cutting tools begin to lose hardness when heated to sufficiently high temperatures. As the tool softens due to heat, it wears and breaks down at the cutting edge or face. Various cutting tool materials begin to lose their hardness at different temperatures. Hence, the ha

30、rdness of the tool and the degree to which it remains its hardness at high temperature are important in the selection of a cutting-tool material. 当刀具进行切削时，刀具刃口处的压力和摩擦产生了高温。达到一定高的温度时，所有的金属切削刀具便开始软化。在刀口因高温而软化的同时，刀具刃口便开始磨耗并损坏。不同的切削刀具材料在不同的温度点开始软化。因此，刀具的硬度和它在高温下所能保持的硬度是选择切削刀具材料时的重要因素。 徐存善主编A cutting too

31、l is wear-resistant if it resists abrasion at the cutting edge and along the tool face. Wear resistance improves as cutting tool hardness increases. Cutting tools must also have high strength in order to be vibration and impact -resistant. Strength in cutting- tool material is not always proportiona

32、l to hardness. Some of the hardest tool materials lack strength because they are too brittle. 如果切削刀具的刃口和刀面耐磨，刀具就不易磨损。切削刀具的硬度越高，耐磨性就越好。切削刀具还必须具有高强度才能抗振动和抗冲击。切削刀具材料的强度并不都是与硬度成正比的。有些硬的刀具材料由于太脆而缺乏强度。 徐存善主编Materials Used in Cutting ToolsThe various materials from which most metal cutting tools are made c

33、an be classified under the following principal headings: Carbon tool steel High-speed steel Cast alloys Cemented carbides Ceramics Diamonds 大多数金屑切削刀具的制作材料可分为以下几大类： 碳素刀具钢；高速钢；铸合金；硬质合金；陶瓷；金刚石。 徐存善主编Tool life, or the number of parts produced by a cutting- tool edge before regrinding is required, is a v

34、ery important cost factor in manufacturing a part or product. Cutting tools must be reground at the first sign of dullness. If a tool is used beyond this point, it will break down rapidly. 刀具寿命，即切削刀刃在需要重新打磨之前能加工的零件数，是生产某个零件或产品的重要成本因素。当切削刀具开始变钝时必须重新打磨。如果在这时还要继续用下去，刀具会很快地磨损。 徐存善主编In order to detect th

35、e time when a cutting tool should be changed, most modern machines are equipped with indicators that show the horsepower used during the machining operation. When a tool becomes dull, more horsepower is required for the operation, which will show on the indicator. When this occurs, the tool should b

36、e reground immediately. 要知道什么时候该换刀具，大部分现代机床都安装了指示器来显示切削加工所耗的功率。当刀具用钝时，加工需要消耗更多的功率，并由指示器显示出来。一旦发生这种情况就应当立即打磨刀具。New words and phrases 徐存善主编variety vraiti n. 多样；种类；杂耍 复数varieties property prCpti n. 性质，性能；财产；所有权severity siveriti n. 严重；严格；猛烈 复数severities wear w n. 穿著，磨损，耐久性 v. 穿著，用旧，耗损impact impkt, impkt

37、 vt.影响；撞击；冲突vi. 冲击n.效果；碰撞；compression kmpreFn n. 压缩，浓缩；压榨，压迫abrasion brein n. 磨损；磨耗；擦伤friction frikFn n. 摩擦，摩擦力hence hens adv. 因此；今后proportional prupC:Fnl adj.比例的，成比例的；相称的n. 比例项New words and phrases 徐存善主编brittle britl adj. 易碎的，脆弱的；易生气的(brittler, brittlest) carbon k:bn n. 碳；碳棒；复写纸adj. 碳的；碳处理的cast k:s

38、, kst vt. 投，抛；计算；浇铸；投射n. 投掷；铸件；铸型cement siment vt. 巩固，加强；接合vi. 粘牢n. 水泥；接合剂carbide k:baid n.【化学】碳化物；碳化钙regrind ri:raind vt. 再磨研，重研磨，再磨dullness dQlnis n. 迟钝，钝度recondition ,ri:kndiFn vt. 修理，修复；重建；更新a variety of 种种；各种各样的impact on 影响；对冲击，碰撞 Exercises 徐存善主编1.What are the most important properties of cutti

39、ng tools? 2. Which factors are important in the selection of a cutting-tool material? Why? IAnswer the following questions according to the reading The most important properties of cutting tools are hardness at high temperature, wear resistance, and impact strength. The hardness of the tool and the

40、degree to which it remains its hardness at high temperature are important in the selection of a cutting-tool material. Because all metal cutting tools begin to lose hardness when heated to sufficiently high temperatures. Exercises 徐存善主编3.How many sorts are classified in the various materials from wh

41、ich most metal cutting tools are made? 4. Why are most modern machines equipped with indicators that show the horsepower used during the rnachining operation? IAnswer the following questions according to the reading The various materials from which most metal cutting tools are made can be classified under the following principal headings: Carbon too