2022年机械工程专业英语 .docx

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1、精选学习资料 - - - - - - - - - Lesson1 1 、 Virtually all machines contain shafts. The most 1 、 the branch of scientific analysis, which deals with motions, time, and forces, is called mechanics and is made up of two parts, statics and dynamics. Statics deals with the analysis of stationary systems, i.e.,

2、those in which time is not a factor, and dynamics deals with systems, which common shape for shafts is circular and the cross section can be either solid or hollow. 实际上,几乎全部的机器中都装有轴；轴的最常见 的外形是圆形,其截面可以是实心的,也可以是空心的（空心轴可以减轻重量）；有时也采纳矩形轴,例如,change with time. 螺丝起子的头部 .套筒扳手和掌握旋钮的杆；对运动时间和作用力作出科学分析的分支成为力 2 、

3、A shaft must have adequate torisonal strength to 学；他由静力学和动力学两部分组成；静力学对静止系 统进行分析,即在其中不考虑时间这个引述,动力学对 大事而变化的系统进行分析；2 、 Any two such forces acting on a body constitute a couple. The arm of the couple is the perpendicular distance between their lines of action, and the plane of the couple is the plane co

4、ntaining the two lines of action. 作用在一个刚体上的两个这样的的里构成一个力 偶；力偶臂是这两个条作用线之间的垂直距离,力偶面 是包含着两条作用线的平面；3、 Mechanics deal with two kinds of quantities: scalars and vectors. Scalar quantities are those with which a transmit torque and not be over stressed it must also be torsional stiff enough so that one moun

5、ted component does not deviate excessively from its original angular position relative to a second component mounted on the same shaft. 为了在传递扭矩时不发生过载,轴应当有适当的抗 扭强度；轴仍应当具有足够的抗扭强度,以使在同一轴 上的两个传动零件之间的相对转角不会过大；3 、Components such as gears and pulleys are mounted on shafts by means of key. The design of the

6、 key and the corresponding keyway in the shaft must be properly evaluated. For example, stress concentrations occur in shafts due to keyways, and the material removed to from magnitude alone is associated. Examples of scalar the keyway further weakens the shaft. quantities in mechanics are time, vol

7、ume, density, speed, energy, and mass. Vector quantities, on the other hand, possess direction as well as magnitude. Examples of vectors are displacement, velocity, acceleration, force, moment, and 齿轮和皮带轮等零件通过键连接在轴上；在键及轴 上与之相对应的键槽的设计中,必需进行认真的运算；例如,轴上的键槽会引起应力集中,由于键槽的存在会 使轴的横截面积减小,会进一步减弱轴的强度；momentum.

8、 和矢量；标量是那些4、Another important aspect of shaft design is the method 力学涉及两种类型的量,标量of directly connecting one shaft to another. Devices such as 只有大小的量；在力学中标量的例子有时间、体积、密 度、速率、能量和质量；另一方面,矢量既有大小又 有大小又有方向；矢量的例子有位移、速度、加速度、rigid and flexible couplings accomplish this. 轴的设计工作中的另一个重要方面是一根轴与另一根轴之间的直接连接方法；这是由刚性或

9、者弹性联轴器来实力、力矩、动量；现的；Lesson2（此课后面没翻译,翻译的不太精确谅解）Lesson5 1 、The turning of a part in a lathe is another example of several forces in action. （as shown in figure1 ）1 、 The term shaft usually refers to a relatively long member of round cross section that rotates and transmits 车床车削是一些力在起作用的另一个例子；figure1 如p

10、ower. One or more members such as 图；gears ,sprockers,pullys,and cams are usually attached to the 2 、 If this workpiece is held between the centers of the lathe, the centers exert a compressive force against the shaft by means of pins, keys,splines,snap rings,and other devices . These latter members

11、are among the associated work. ,中心车床对工作parts consedered in this text,as ate couplings and universal 假如这个工件在放在车床中心之间joints , which serve to connect the shaft to the source of 产生压力；power or load. 3、 Rotary motion is required to drill holes, turn parts in a lathe, mill surfaces, or drive a generator or

12、 fan belt. 2、 It is apparent that shafts can be subjected to various combinations of axial,bending,and torsional loads,and that 扶轮运动需要去钻孔,在车床上转换两件,表面 ,或驱these loads may be static or fluctuating. 动发电机或风扇皮带3、Torsional defection can affect the accuracy of a cam or 4 、Harmonic and Intermittent Motion （谐

13、和运动和间歇gear driven mechanism .Furthermore,the greater the 运动） : Any simple vibration, such as the regular back, and flexibility -either lateral or torsional-the lower the forth movement of the end of a pendulum, is simple harmonic motion. corresponding critical speed. 4、A gear can be gripped axially

14、between a shoulder on the Lesson4 名师归纳总结 - - - - - - -shaft and a spacer ,with torque being transmitted through a 第 1 页,共 5 页精选学习资料 - - - - - - - - - keyways. become necessary which may increase frictional drag . Lesson7 在转速高的场合需要有特地的冷却装置,而这可能会1、Fasteners are devices which permit one part to be join

15、ed 增大摩擦阻力；to a second part and ,hence,they are involved in almost all designs . The acceptability of any product depends not only on the selected components , but also on the means by which they are fastened together. The principal purposes of fasteners are to provide the following design features ；

16、紧固件是将一个零件与另一个零件进行连接的零件；因此,几乎在全部的设计中都要用到紧固件；人们对于任何产品的中意程度不仅取决于其组成部件,仍取决于2 、 It is not surprising that ,owing to the high stresses involved,a predominant form of failure shouls be metal fatigue,and a good deal of work is currently in progress intended to improve the reliability of this type of bearing

17、 . 滚动轴承由于在工作中会产生高的应力,其主要失效 形式是金属疲惫,这一点并不古怪,目前正在进行大量 的工作以求改进这种轴承的牢靠性；3、 The fit of the bearing races onto the shaft or onto the 其连接方式；housing is of critical importance because of their combined 2 、 The importance of fasteners can be realized when referring ro any complex product,In the case of the ef

18、fect on the internal clearance of the bearing as well as preserving the desired degree of interference fit. automobile,there are literally thousands of parts which are 轴承套圈与轴或轴承座的的协作特别重要,由于它fastened together to produce the total product.The failure or loosening of a single fastener could result in a

19、 simple nuisance such as a door rattle or in a serious situation such as a wheel coming off. Such possibilities must be taken into account in the selection of the type of fatener for the specific application. 通过任何一个复杂的产品,都可以熟悉到紧固件在其 中的重要性；以汽车为例,它是由数千个零件连接在一 起而成为一辆车；一个紧固件的失效或松脱可能会带来们之间的协作不仅应当保证所需要的过盈

20、量,而且也应 该保证轴承的内部间隙；4、The inner race is frequently located axially by abutting against a shoulder .Aradius at this point is essential for the avoidance of stress concentration and ball races rae providede with a radius or chamfer to allow space for this . 内圈通常是通过紧靠在轴肩上进行轴向定位的；轴肩 出的圆弧半径主要是为了防止应力集中；在轴承内

21、圈上 加工出一个圆弧或者倒角,用来供应容纳轴肩处圆弧半像车门嘎嘎响这类小麻烦,也可能造成像车轮脱落这种 径的空间；严峻的后果；因此,在为一个特定的用途挑选紧固件 时,应当考虑到上述各种可能性；5、Where life is not the determing factor in design ,it is usual to determine maximum loading by the amount to Lesson8 fasterners perform the function of which a bearing will deflect under load . 1 、Thread

22、ed 在使用寿命不是设计中的打算因素的场合,通常根locating ,clamgping ,adjusting ,and transmiting force from 据轴承担载荷时产生的变形量来确定其最大载荷；one machine member to another .They are thoroughly Lesson13 standardized and generally designed for use in mass 1、One of the primary considerations in designing any production of machines. 2、 Ma

23、tching external and internal threads so that they are may be assembled is the key to all thread fasteners. 3、 A particular SAE grade specilication can be met by a number of different steels, thus faster manufacturers have machine or structure is that the strength must be sufficiently greater that th

24、e stress to assure both safety and reliability. To assure that mechanical parts do not fail in service, it is necessary to learn why they sometimes do fail. Then we shall be able to relate the stresses with the strengths to some latitude in selecting the materials best suited to their achieve safety

25、. specific production faclities. 4、 For moderate loads and speedes the correct selection of a standard of the bearing on the basis of load rating will usually secure satisfactory performance. 对于中等载荷和 转速,依据额定负荷挑选一个标准轴承,通常都可以保 证其具有令人中意的工作性能；5、The deflection of less magnitude than that of the shafts or

26、 other components associated with the bearing . 当载荷较 大时,轴承零件的变形,尽管它通常小于轴和其它与轴承一起工作的零部件的变形,将会变得重要起来；在设计任何机器或者结构时,所考虑的主要事项之 一是其强度应当比它所承担的应力要大得多,以确保安 全与牢靠性；要保证机械零件在使用过程中不发生失 效,就必需知道它们在某些时候会失效的缘由,然后,才能将应力与强度联系起来,以确保其安全；2 、 Ideally, in designing any machine element, the engineer should have at his dispos

27、al the results of a great many strength tests of the particular material chosen. These tests should have been made on specimens having the same heat treatment, surface roughness, and size as the element Lesson9 he proposes to design, and the tests should be made under 1 、 Where speeds are high speci

28、al cooling arrangements exactly the same loading conditions as the part will 名师归纳总结 - - - - - - -第 2 页,共 5 页精选学习资料 - - - - - - - - - experience in service. 设计任何机械零件的抱负情形为,工程师可以利用大量的他所选用的这种材料的强度试验数据；这些试验工作图是将设计变为实际产品所依据的图样；全部的正 投影原理和绘图技术都可以用来在工作图中表达一个工 程中的细节；零件图是在一整套工作图中关于一个零件应当在与所设计的零件有相同的热处理,表面粗糙度和

29、（或细节）的工作图；尺寸大小的试件进行,而且试验应当在与零件使用过程 Title Blocks In practice, title blocks usually contain the 中承担的载荷完全相同的情形下进行；3、 Most hardness-testing systems employ a standard load which is applied to a ball or pyramid in contact with the material to be tested. The hardness is then expressed as a function of the

30、size of the resulting indentation. This title or part name, drafter, date, scale, company, and sheet number. Other information, such as tolerances, checkers, and materials, also may be given. Any modifications or changes added after the first version to improve the design is shown in the revision me

31、ans that hardness is an easy property to measure, blocks. because the test is nondestructive and test specimens are not required. Usually the test can be conducted directly on an actual machine element. 大多数硬度试验系统是将一个标准的载荷加在与被标题栏在实践中,标题栏中通常包括标题或零件名称、制图员、日期、比例、公司和图号；另外,仍可以包含 公差、审核人员和材料等信息；在第一次制图之后,任 何

32、为了改进设计方案而作的修改和更正都应当在修改栏试验材料相接触的小球或者棱锥上；因此,硬度可以表 中标示为所产生的压痕尺寸函数；这说明由于硬度是非破坏 明；性试验,而且不需要特地的试件,因而硬度是一个简单 测量的性能；通常可以直接在实际的机械零件上进行硬The allocation of proper production tolerances is therefore a most important task if the finished product is to achieve its 度试验；manufacture of any product is intended purpose

33、 and yet be economical to produce. The Lesson17 size of the tolerances, as specified by the designer, depends 1、 The first step in the on the many conditions pertaining to the design as well as design, which usually takes place in several distinct stages: on past experience with similar products if

34、such experience a conceptual ； b functional ； c production design. is available. During the conceptual design stage, the designer is 要使产品能够以较低的价格被生产出来并且能够满意设concerned primarily with the functions the product is to 计的要求,规定适当的加工公差是最为重要的工作；公fulfill. 差的大小是由设计人员所确定的,它取决于很多与设计制造任何产品的第一步工作都是设计；设计通常可 有关的条件以

35、及过去在设计类似产品时所获得的体会以分为几个明确的阶段；（a）概念设计； b 功能设计 c （假如有这方面体会的话）；生产设计；在概念设计阶段,设计者着重考虑产品应当A part is said to be at the least material condition LMC 具有的功能；when the dimensions are all at the limits that give a part 2、 Often a prototype or working model is made that can be tested to permit evaluation of the pr

36、oduct as to function, reliability, appearance, serviceability, and so on. with the smallest amount of material. 当全部的尺寸都处在答应零件含有的材料量为最小的极限 状 态 时 , 就 称 这 个 零 件 处 于 最 小 实 体 状 态通常要制造出样机或着实物模型,并对其进行实（LMC ）；验,评判产品的功能、牢靠性、外观和修理保养性等 3、 As manufacturing progresses, it is inevitable that situations will arise

37、 that may require modifications of the If the variations due to chance causes are too great, it is usually necessary to move the operation to more accurate equipment rather than spend more effort in materials being used. Experience may reveal that trying to improve the process. substitution of cheap

38、er materials can be made. 在制造过程中,不行防止地会显现对使用中的材料假如随机缘由对尺寸变化的影响过大,一般来说采纳更 精密的加工设备,要比花费更多精力来转变生产过程更做一些更换的情形；体会说明,可以采纳某些廉价材料 为有效作为代替；Lesson29 24/27 课 1、The technique of dimensioning parts within a Working drawings are the drawings from which a design is implemented. All principles of orthographic proje

39、ction and techniques of graphics can be used to communicate the details of a project in working drawings. A detail drawing is a working drawing of a single part or detail within the set require range of variation to ensure interchangeability is called tolerancing. Each dimension is allowed a certain

40、 degree of variation within a specified zone ,or tolerance .for example, a parts dimension might be expressed as 20+-0.50,which allows a tolerance variation in size of 1.00 of working drawings. mm. 第 3 页,共 5 页名师归纳总结 - - - - - - -精选学习资料 - - - - - - - - - 给零件标注尺寸使其在一个规定的区间内变动,以保set and adjusted ,littl

41、e skill is required to turn out duplicate 证他们具有互换性的技术称为公差技术；答应每个尺寸 parts. 在规定范畴内具有肯定的变动量,称为公差；例如,一 高生产率的砖塔车床是装有很多动力附件的特别复杂个零件的尺寸可以被表示成 20+-0.50 ,其公差（尺寸变 的机器；然而,全部砖塔车床的主要特点是刀具能按适动量）为 1.00mm；当次序完成一系列的加工工序；一旦这些刀具被安装调单词 basic hole system 基孔制 basic shaft system 基轴整好后只只需要很低的技术就可以车削加工很多相同的制 零件；Leesson33 4、

42、The first screw machine were designed to feed bar 1Engineering and technology students must became stock and wire used in making small screw parts. computer literate, to understand the applications of 单轴自动螺丝车床,顾名思义,一次仅能加工一根棒computer and their advantages. Not to do so will place 料；students at a serio

43、us disadvantage in pursuing their careers. With the single spndle machine, the turret indexes around 工程技术专业的同学们应当通晓运算机,明白运算机的 the spindle. 用途和它们的优点；不这样做,就会使同学们在将来的 职业生涯中处于特别不利的位置；在单轴车床上,砖塔环绕主轴转位；With a multiple spindle maching , however ,the spindle 2、Engineers generally agree that the computer does

44、 not itself indexes. change the nature of the design process but is a significant 然而,在多轴自动车床上,主轴自己转位；tool that improves efficiency and productivity 6、A vertical turret lathe is basically a turret lathe that 工程师们通常认为运算机不会转变设计过程的性质；3 、 Computer of applications in engineering and other technical fields

45、. Most graphical solutions that are possible has been stood on its headstock end. 立式砖塔车床基本上就是将其从床头箱一端向下而竖立起来的一台砖塔车床；with a pencil can be done on a computer and usually more 7、Many of todays more sophisticated lathes are productively. Applications vary from 3D modeling and finite element analysis to

46、2D drawings and mathematical called machining centers since they are capable of performing, in addition to the normal turning caiculation. operations, certain milling and drilling operations. 运算机图形学在工程技术领域的应用几乎没有任何限 制,大部分可以铅笔完成的图解方法都可以用运算机完当前很多技术更为先进的车床叫做加工中心；由于 他们除了完成常规的车削工作之外,仍可以完成某些铣成,而且通常效率更高；其应用从建立三维模型和有限 削钻削工作元分析,直到绘制平面图和进行数字运算；4、These systems offer many advantagees over traditional 单词： turret 砖塔,六角刀架,六角头 general purpose 多方面的,多种用途的design and manufacturing systems, ineluding less design Lesson65 , to the Tool & Manufacturing English effort, more eff