機(jī)械專業(yè)英語董建國 第2章

1、Unit 2TEXT READING MATERIAL Unit 2Unit 2TEXTPrimary Motion and Feed Motion Broadly speaking，two kinds of relative motion must be provided by a machine toolthe primary motion and the feed motionCombination of these two motions will lead to a chip removal and the creation of machined surface with desi

2、red geometry. As a rule，the primary motion absorbs most of total power which is required to perform a machining operation. The feed motion may proceed by steps or continuously and absorb a small proportion of the total power Unit 2 Turning means machining a piece of rotating metal by pressing a hard

3、ened cutting tool against it. The work is given the primary motion while the tool is fed continuously. The process of planing and shaping is removing metal in a series of straight cuts. In planing, the work is given a linear motion while the tool remains motionless during the cutting stroke and is p

4、rovided with a lateral feeding movement during the return stroke. In the case of the shaper, the kinematic relationship between work and tool is reversed; however, the cutting action principle is the same. Drilling consists of rotating a cutting tool and advancing the tool along its own axis into a

5、stationary work-piece to produce a round hole. Of the two functions，advancing the tool along its axis is the major consideration in the design of drilling machines. Rotating the drill is, by comparison, a simple matter.Unit 2Fig. 2-1 Primary motion and feed motion Unit 2 LEARN TO SPEAK John：How do y

6、ou do! My name is John. Miss Li:How do you do! John：Are there any vacancies in your factory? Miss Li:Yes. We need some new workers. What subject was your major? John：I majored in mechanical manufacturing, and I think I am good at operating milling machine.Unit 2Miss Li:What sort of job do you like t

7、o do?John：I would like to be milling worker. I think I can do my best to it. Miss Li:Great! What time can you start to work?John：Anytime.Miss Li:Very nice. How much do you expect in salary?John：800 yuan.Miss Li:OK! Please fill in this form. If anything turns, Ill contact with you.John：Thank you!Miss

8、 Li:Youre welcome. Unit 2NEW WORDS AND EXPRESSIONSprimary 5praImErI adj. 第一位的，初級的broad brC:d adj. 寬的broadly adv. 概括地，大致地removal rI5mu:v(E)l n. 移動，切除geometry dVI5RmItrI n. 幾何形狀，幾何學(xué)absorb Eb5sC:b vt. 吸收，吸引proceed prE5si:d vi. 進(jìn)行，發(fā)生continuous kEn5tInjJEs adj. 連續(xù)的，持續(xù)的continuously adv. 連續(xù)不斷地Unit 2proport

9、ion prE5pC:F(E)n n. 比例，部分linear 5lInIE(r) adj. 直線的，線性的motionless 5mEJF(E)nlIs adj. 不動的，靜止的lateral 5lAtEr(E)l adj. 橫(向)的return rI5tE:n v.&n. 返回，退回kinematic kB:nI5mAtIk adj. 運(yùn)動學(xué)(上)的relationship rI5leIFEnFIp n. 關(guān)系reverse rI5vE:s v.&n. 相反，背面，倒退 Unit 2adj. 相反的reversely adv. 相反principle 5prInsIp(E)l n. 原則

10、，原理advance Ed5vB:ns; (?) Ed5vAnsv. 前進(jìn)，推進(jìn)axis 5AksIs n. 軸axes 5AksIz n. 軸(復(fù)數(shù))round raJnd adj. 圓的prep. 圍著adv. 圍繞著Unit 2 consideration kEnsIdE5reIF(E)n n. 考慮comparison kEm5pArIs(E)n n. 比較matter 5mAtE(r) n. 事件，物質(zhì)mechanical mI5kAnIk(E)l adj. 機(jī)械的manufacturing 9mAnjJ5fAktFErIN n. 制造業(yè)vacancy 5veIkEnsI n. 空缺

11、Unit 2 primary motion 主運(yùn)動broadly speaking 概括地講lead to 導(dǎo)致as a rule 通常，照例by steps 逐步地a small proportion of 小部分linear motion 線性運(yùn)動lateral feeding movement 橫向進(jìn)給運(yùn)動return stoke 返回行程take into consideration 對加以考慮，考慮到by comparison 比較起來Unit 2NOTES 1. Broadly speaking，two kinds of relative motion must be provid

12、ed by a machine toolthe primary motion and the feed motion概括地講，機(jī)床必須提供兩種相對運(yùn)動主運(yùn)動與進(jìn)給運(yùn)動。 “Broadly speaking”是插入語，這里可譯為“一般講”。破折號后面的內(nèi)容“the primary motion and the feed motion”實際上是解釋“two kinds of relative motion”，不要認(rèn)為破折號在“a machine tool”后面，就誤以為“the primary motion and the feed motion”是解釋“a machine tool”的。在英語中

13、，很多場合使用被動語態(tài)，賓語放在了前面，而主語放在了后面，造成了中心詞與解釋中心詞的內(nèi)容從形式上看被分開了，因而在翻譯時要特別引起注意。 Unit 2 2. As a rule，the primary motion absorbs most of total power which is required to perform a machining operation.通常，主運(yùn)動要消耗切削加工所需要的總功率中的大部分。 “as a rule”作為一個整體，其含義為“通?！?。“which”引導(dǎo)的是定語從句，用來進(jìn)一步解釋“total power”是用來干什么的。 Unit 2 3. The

14、work is given the primary motion while the tool is fed continuously. 工件做主運(yùn)動，而刀具則做連續(xù)進(jìn)給運(yùn)動。 “be given” (被給)?？勺g成“得到”、“獲得”。例如： I am given a book. 我得到一本書。 In turning, the work is given the primary motion. 車削時，工件獲得主運(yùn)動。 Unit 2 4. Of the two functions，advancing the tool along its axis is the major considerat

15、ion in the design of drilling machines. 在這兩種功用中，使鉆頭沿自身的軸線進(jìn)給是設(shè)計鉆床時主要考慮的問題。 “Of” 放在句首表示“在中”，例如： Of all machine tools, the lathe is the most common one. 在所有的機(jī)床中，車床是最普通的一種。 Of all metals, steel is the most widely used in engineering. 在所有的金屬中，鋼在工程上用得最普遍。Unit 2 有時把句子從英文翻譯成中文時要根據(jù)上下文的意思適當(dāng)?shù)丶釉~，以使句子讀起來通俗易懂。本句在

16、翻譯時，在兩種功用的前面加上了一個定語“加工出一個孔的”，雖然本句中沒有對應(yīng)的英文，但從上一句討論的鉆削中，我們就可以知道是在講加工一個孔。 Unit 2EXERCISES 1Discuss the following questions in English: (1) What is the primary motion? (2) What is the feed motion? (3) What is turning? (4) What is drilling?Unit 2 2Use English for replacing Chinese or use Chinese for repl

17、acing English. (1) 相對運(yùn)動 (2) 加工表面 (3) 機(jī)械制造 (4) Desired geometry (5) A machining operation (6) Rotating a cutting toolUnit 2READING MATERIALPower in The Workshop The processes of cutting metal generally require some power so that the application of power to workshop processes is importantEnergy is req

18、uired in various forms by machine tools，for example，reciprocating motion to a planer table，longitudinal feed to a lathe carriage, rotational motion to a drill，etc., but it is nearly always supplied to the machine in the form of rotational energy at the pulleyOne of the functions of the machine is to

19、 convert the rotational energy into the required formEnergy is supplied to most of our workshops in the form of electricity，and it is converted to rotational energy by means of an electric motor. Unit 2 Early machine tools were driven by a reciprocating steam engine through a system of pulleys, belt

20、s，and clutchesUsually，a single steam engine provided the power for several machine tools in the workshopLater, a single electric motor replaced the steam engine to drive a group of machine toolsIn modern workshops，most of the machine tools are provided with individual motor driveEach machine has its own el