机械工程专业英语

Lesson1 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 those in which time is not a factor and dynamics deals with systems which change with time 对运动时间和作用力作出科学分析的分支成为力学 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 动力学对事件 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 containing 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 magnitude alone is associated Examples of scalar quantities in mechanics are time volume 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 momentum 力学涉及两种类型的量 标量 和矢量 标量是那些 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 力 力矩 动量 Lesson2 此课后面没翻译 翻译的不太准确谅解 1 The turning of a part in a lathe is another example of several forces in action as shown in figure1 车床车削是一些力在起作用的另一个例子 figure1 如 图 2 If this workpiece is held between the centers of the lathe the centers exert a compressive force against the work 如果这个工件在放在车床中心之间 中心车床对工作 产生压力 3 Rotary motion is required to drill holes turn parts in a lathe mill surfaces or drive a generator or fan belt 扶轮运动需要去钻孔 在车床上转换两件 表面 或驱 动发电机或风扇皮带 4 Harmonic and Intermittent Motion 谐和运动和间歇 运动 Any simple vibration such as the regular back and forth movement of the end of a pendulum is simple harmonic motion Lesson4 1 Virtually all machines contain shafts The most common shape for shafts is circular and the cross section can be either solid or hollow 实际上 几乎所有的机器中都装有轴 轴的最常见 的形状是圆形 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 有时也采用矩形轴 例如 螺丝起子的头部 套筒扳手和控制旋钮的杆 2 A shaft must have adequate torisonal strength to transmit torque and not be over stressed it must also be torsional stiff enough so that one mounted 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 轴应该有适当的抗 扭强度 轴还应该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 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 the keyway further weakens the shaft 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 必须进行认真的计算 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 4 Another important aspect of shaft design is the method of directly connecting one shaft to another Devices such as 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 这是由刚性或者弹性联轴器来实 现的 Lesson5 1 The term shaft usually refers to a relatively long member of round cross section that rotates and transmits power One or more members such as gears sprockers pullys and cams are usually attached to the shaft by means of pins keys splines snap rings and other devices These latter members are among the associated parts consedered in this text as ate couplings and universal joints which serve to connect the shaft to the source of power or load 2 It is apparent that shafts can be subjected to various 2 combinations of axial bending and torsional loads and that these loads may be static or fluctuating 3 Torsional defection can affect the accuracy of a cam or gear driven mechanism Furthermore the greater the flexibility either lateral or torsional the lower the corresponding critical speed 4 A gear can be gripped axially between a shoulder on the shaft and a spacer with torque being transmitted through a keyways Lesson7 1 Fasteners are devices which permit one part to be joined 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 紧固件是将一个零件与另一个零件进行连接的零件 因此 几乎在所有的设计中都要用到紧固件 人们对于 任何产品的满意程度不仅取决于其组成部件 还取决于 其连接方式 2 The importance of fasteners can be realized when referring ro any complex product In the case of the automobile there are literally thousands of parts which are fastened together to produce the total product The failure or loosening of a single fastener could result in a 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 都可以认识到紧固件在其 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 像车门嘎嘎响这类小麻烦 也可能造成像车轮脱落这种 严重的后果 因此 在为一个特定的用途选择紧固件时 应该考虑到上述各种可能性 Lesson8 1 Threaded fasterners perform the function of locating clamgping adjusting and transmiting force from one machine member to another They are thoroughly standardized and generally designed for use in mass production of machines 2 Matching 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 some latitude in selecting the materials best suited to their 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 根据额定负荷选择一个标准轴承 通常都可 以保证其具有令人满意的工作性能 5 The deflection of less magnitude than that of the shafts or 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 Lesson9 1 Where speeds are high special cooling arrangements become necessary which may increase frictional drag 在转速高的场合需要有专门的冷却装置 而这可能会 增大摩擦阻力 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 滚动轴承由于在工作中会产生高的应力 其主要失效 形式是金属疲劳 这一点并不奇怪 目前正在进行大量 的工作以求改进这种轴承的可靠性 3 The fit of the bearing races onto the shaft or onto the housing is of critical importance because of their combined effect on the internal clearance of the bearing as well as preserving the desired degree of interference fit 轴承套圈与轴或轴承座的的配合非常重要 因为它 们之间的配合不仅应该保证所需要的过盈量 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避免应力集中 在轴承内圈上 加工出一个圆弧或者倒角 用来提供容纳轴肩处圆弧半 径的空间 5 Where life is not the determing factor in design it is usual to determine maximum loading by the amount to which a bearing will deflect under load 在使用寿命不是设计中的决定因素的场合 通常根 据轴承受载荷时产生的变形量来确定其最大载荷 Lesson13 1 One of the primary considerations in designing any machine or structure is that the strength must be sufficiently greater that the stress to assure both safety and reliability 3 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 achieve safety 在设计任何机器或者结构时 所考虑的主要事项之 一是其强度应该比它所承受的应力要大得多 以确保安 全与可靠性 要保证机械零件在使用过程中不发生失效 就必须知道它们在某些时候会失效的原因 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 disposal 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 he proposes to design and the tests should be made under exactly the same loading conditions as the part will experience in service 设计任何机械零件的理想情况为 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 应该在与所设计的零件有相同的热处理 表面粗糙度和 尺寸大小的试件进行 而且试验应该在与零件使用过程 中承受的载荷完全相同的情况下进行 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 size of the resulting indentation This means that hardness is an easy property to measure 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 试验材料相接触的小球或者棱锥上 因此 硬度可以表 示为所产生的压痕尺寸函数 这表明由于硬度是非破坏 性试验 而且不需要专门的试件 因而硬度是一个容易 测量的性能 通常可以直接在实际的机械零件上进行硬 度试验 Lesson17 1 The first step in the manufacture of any product is design which usually takes place in several distinct stages a conceptual b functional c production design During the conceptual design stage the designer is concerned primarily with the functions the product is to fulfill 制造任何产品的第一步工作都是设计 设计通常可 以分为几个明确的阶段 a 概念设计 b 功能设计 c 生产设计 在概念设计阶段 设计者着重考虑产品应 该具有的功能 2 Often a prototype or working model is made that can be tested to permit evaluation of the product as to function reliability appearance serviceability and so on 通常要制造出样机或着实物模型 并对其进行实验 评价产品的功能 可靠性 外观和维修保养性等 3 As manufacturing progresses it is inevitable that situations will arise that may require modifications of the materials being used Experience may reveal that substitution of cheaper materials can be made 在制造过程中 不可避免地会出现对使用中的材料 做一些更改的情况 经验表明 可以采用某些便宜材料 作为代替 24 27 课 Working drawings are the drawings from which a design is implemented All principles of orthographic projection 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 of working drawings 工作图是将设计变为实际产品所依据的图样 所有的正 投影原理和绘图技术都可以用来在工作图中表达一个项 目中的细节 零件图是在一整套工作图中关于一个零件 或细节 的工作图 Title Blocks In practice title blocks usually contain the 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 blocks 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 还可以 包含公差 审核人员和材料等信息 在第一次制图之后 任何为了改进设计方案而作的修改和更正都应该在修改 栏中标 明 The allocation of proper production tolerances is therefore a most important task if the finished product is to achieve its intended purpose and yet be economical to produce The size of the tolerances as specified by the designer depends on the many conditions pertaining to the design as well as on past experience with similar products if such experience is available 要使产品能够以较低的价格被生产出来并且能够满足设 计的要求 规定适当的加工公差是最为重要的工作 公 4 差的大小是由设计人员所确定的 它取决于许多与设计 有关的条件以及过去在设计类似产品时所获得的经验 如果有这方面经验的话 A part is said to be at the least material condition LMC when the dimensions are all at the limits that give a part with the smallest amount of material 当所有的尺寸都处在允许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 LMC 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 trying to improve the process 如果随机原因对尺寸变化的影响过大 一般来说采用更 精密的加工设备 要比花费更多精力来改变生产过程更 为有效 Lesson29 1 The technique of dimensioning parts within a require range of variation to ensure interchangeability is called tolerancing Each dimension is allowed a certain degree of variation within a specified zone or tolerance for example a part s dimension might be expressed as 20 0 50 which allows a tolerance variation in size of 1 00 mm 给零件标注尺寸使其在一个规定的区间内变动 以保 证他们具有互换性的技术称为公差技术 允许每个尺寸 在规定范围内具有一定的变动量 称为公差 例如 一 个零件的尺寸可以被表示成 20 0 50 其公差 尺寸变 动量 为 1 00mm 单词 basic hole system 基孔制 basic shaft system 基轴制 Leesson33 1Engineering and technology students must became computer literate to understand the applications of computer and their advantages Not to do so will place students at a serious disadvantage in pursuing their careers 工程技术专业的学生们应该通晓计算机 了解计算机的 用途和它们的优点 不这样做 就会使学生们在将来的 职业生涯中处于非常不利的地位 2 Engineers gene rally agree that the computer does not change the nature of the design process but is a significant tool that improves efficiency and productivity 工程师们通常认为计算机不会改变设计过程的性质 3 Computer of applications in engineering and other technical fields Most graphical solutions that are possible with a pencil can be done on a computer and usually more productively Applications vary from 3D modeling and finite element analysis to 2D drawings and mathematical caiculation 计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计算机完 成 而且通常效率更高 其应用从建立三维模型和有限 元分析 直到绘制平面图和进行数字计算 4 These systems offer many advantagees over traditional design and manufacturing systems ineluding less design effort more efficent material use reduced lead tine greater accuracy and improved inventory controi 包括减少时间工作量 提高材料利用率 缩短产品研制 周期 提高精度和改善库存管理 graphics has an aimost limitless number Lesson36 1 engin lathes of course are general purpose machines used in production and maintenance shops all over the world 普通车床是全世界的生产车间和维修车间里广泛使 用的通用机床 2 The tracer or duplicating lathe is designed to produce irregularly shaped parts automatically 靠模车床或仿形车床被设计用来对形状不规则的零 件进行自动加工 3 machines with a wide variety of power accessories Theprincipal feature of all turret lathes however is that the tools can perform a consecutive serials of operations in proper sequence Once the tools have been set and adjusted little skill is required to turn out duplicate parts 高生产率的砖塔车床是装有许多动力附件的非常复杂 的机器 然而 所有砖塔车床的主要特点是刀具能按适 当顺序完成一系列的加工工序 一旦这些刀具被安装调 整好后只只需要很低的技术就可以车削加工很多相同的 零件 4 The first screw machine were designed to feed bar stock and wire used in making small screw parts 单轴自动螺丝车床 顾名思义 一次仅能加工一根棒 料 With the single spndle machine the turret indexes around the spindle 在单轴车床上 砖塔围绕主轴转位 With a multiple spindle maching however the spindle itself indexes 然而 在多轴自动车床上 主轴自己转位 6 A vertical turret lathe is basically a turret lathe that 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 5 立起来的一台砖塔车床 7 Many of today s more sophisticated lathes are called machining centers since they are capable of performing in addition to the normal turning operations certain milling and drilling operations 当前许多技术更为先进的车床叫做加工中心 因为 他们除了完成常规的车削工作之外 还可以完成某些铣 削钻削工作 单词 turret 砖塔 六角刀架 六角头 general purpose 多方面的 多种用途的 Lesson65 1 According to the Tool Manufacturing English Handbook process planning is the systematic determination of the methods by which a product is to be manufactured economically and competitively 根据 工具与制造工程师手册 工艺设计就是系统地 确定能够经济地和有竞争力地将产品制造出来的方法 2 A planner must manage and retrieve a great deal of data and many documents including established standards machinability data machine specifications tooling inventories stock availability and existing process plans 工艺人员应该管理和检索大量的数据和很多文件 其中 包括已建立的标准 可加工性数据 机器的规格 工艺 装备的清单 原材料库存量和一些目前正在应用的工艺 文件 3 This is primarily an information handing job and the computer is an ideal companion 这主要是一些信息处理工作 而计算机是完成这项工作 的一个理想助手 4 Most important for CIM computer aided process machine readable data instead of handwritten plans Such data can readily be transferred to other systems within the CIM hierarchy for use in planning 对计算机集成制造最为重要的是 计算机辅助工艺设计 可以生成机器可以阅读数据 而不是手写的规程 这种 数据可以传递到计算机集成制造体系中的另一个系统中 用以编制工艺规程 5 In the variant approach a set of standard process plans is established for all parts families that have been identified through group technology 在派生法中 对采用成组技术确定的一个零件族中的所 有零件 编制一套标准的加工工艺规程 6 Again GT helps to place the new part in an appropriate family The standard plan is then edited to suit the specific requirements of a particular job 成组技术可以帮助把新零件归类于适当的零件族中 通 过对标准工艺规程的编辑 可以满足对特定工作的专门 要求 7 In the generative approach an attempt is made to synthesize each individual plan using appropriate algorithms that define the various technological decisions that must be made in the course of manufacturing 在创成法中 通过采用确定加工制造过程中各种工艺决 策的适当算法 将各个单独的工艺规程综合起来 Lesson66 1 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 were manually operated and controlled 先进制造技术中的一个最基本的概念是数字控制 NC 在数控技术出现之前 所有的机床都是有人工 操作和控制的 2 Among the many limitations associated with manual control machine tolls perhaps none is more prominent than the limitation of operator skills 在与人工可控制的机床有关的很多局限性中 操作 者的技术大概是最突出的问题 3 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 lower 数字控制的机器比人工操纵的机器的精度更高 生 产零件的一致性更好 生产速度更快 而且长期的工艺 装备成本更低 4 The development of a concept know