机械类专业英语阅读教程lesson15
机械工程专业英语 第一课文及阅读材料
Lesson1 the mechanical design process 1, the mechanical design processThe ultimate objective of mechanical design is to produce a useful product that satisfies the needs of a customer and that is safe ,efficient, reliable, economical, and practical to manufacture .think broadly when answering the question ,”who is the customer for the product or system I am about to design?”it is essential that you know the desires and expectations of all customers before product design. marketing professionals are often employed to manage the definition of customer expectations , but designers will likely work with them as a part of a product development team .many methods are used to determine what the customer wants. One popular method , called quality function deployment or QFD , seeks(1) to identify all of the features and performance factors that customers desire and (2) to assess the relative importance of these factors. the result of the QFD process is a detailed set of functions and design requirements for the product.It is also important to consider how the design process fits with all functions that must happen to deliver a satisfactory product to the customer and to service the product throughout its lift cycle. in fact, it is important to consider how the product will be disposed of after it hasserved its useful life . the total of all such function that affect the product is sometimes called the product realization process or PRP . some of the factors included in PRP are as follows:1 marketing functions to assess customer requirements2 research to determine the available technology that can reasonably be used in the product3 availability of materials and components that can be incorporated into the product4 product design and development5 performance testing6 documentation of the design7 vendor relationships and purchasing functions8 work-force skills9 physical plant and facilities available10 capability of manufacturing systems11production planning and control of production systems12production support systems and personnel13 quality systems requirements14 sales operations and time schedules15 cost targets and other competitive issues16 customer service requirements17 environmental concerns during manufacture , operation anddisposal of the product18 legal requirements19 availability of financial capitalCan you add to this list? You should be able to see that the design of a product is but one part of a comprehensive process. in this text, we will focus more carefully on the design process itself , but the producibility of designs must always be considered . this simultaneous consideration of product design and manufacturing process design is often called concurrent engineering.2 skills needed in mechanical designProduct engineers and mechanical designers use a wide range of skills and knowledge in their daily work . these skills and knowledge are included in the following :1sketching, technical drawing , and computer-aided design2 properties of materials, materials processing, and manufacturing processes3 applications of chemistry, such as corrosion protection, plating , and painting4 statics, dynamics, strength of materials , kinematics, and mechanisms5 fluid mechanics, thermodynamics, and heat transfer6 fluid power, the fundamentals of electrical phenomena, andindustrial controls7 experimental design and performance testing of materials and mechanical systems8 stress analysis9 specialized knowledge of the behavior of machine elements, such as gears, belt drives, chain drives, shafts, bearings, keys, splines, couplings, seals, spring, connections(bolted, riveted, welded, adhesive), electric motors, linear motion devices, clutches, and brakes10 creativity , problem solving ,and project management11 oral communication, listening, technical writing, and teamwork skills3 functions , design requirements and evaluation criteriaSection 1 emphasized the importance of carefully identifying the needs and expectations of the customer prior to beginning the design of a mechanical device. you can formulate these by producing clear , complete statements of functions, design requirements , and evaluation criteria:1 Functions tell us what the device must do , using general , nonquantitative statements that employ action phrases such as “to support a load”, “to lift a crate ”, “to transmit power”, or “to hold two structural members together”, etc2 Design requirements are detailed, usually quantitativestatements of expected performance levels, environmental conditions in which the device must operate, limitations on space or weight , or available materials and components that may be used3 Evaluation criteria are statements of desirable qualitative characteristics of a design that assist the designer in deciding which alternative design is optimum-that is , the design that maximizes benefits while minimizing disadvantagesTogether these elements can be called the specifications for the designMost designs progress through a cycle of activities are outlined in figure1.1. you should typically propose more than one possible alternative design concept. This is where creativity is exercised to produce truly novel designs .Each design concept must satisfy the functions and design requirements . a critical evaluation of the desirable features, advantages, and disadvantages of each design concept should be completed . then a rational decision analysis technique should use the evaluation criteria to decide which design concept is the optimum and , therefore , should be produced.Reading materialMechanical design is the process of designing and/or selecting mechanical components and putting them together to accomplish a desired function. Of course machine elements must be compatible ,must fit well together , and must perform safely and efficiently. The designer must consider not only the performance of the element being designed at a given time , but also the elements with which it must interface.To illustrate how the design of machine elements must be integrated with a larger mechanical design , let us consider the design of a speed reducer for the small tractor . suppose that,to accomplish the speed reduction ,you decide to design a double-reduction, spur gear speed reducer. You specify four gears , three shafts , six bearings, and a housing to hold the individual elements in proper relation to each other. The primary elements of the speed reducer are :1 the input shaft is to be connected to the power source, a gasoline engine whose output shaft rotates at 2000 rpm . a flexible coupling is to be employed to minimize difficulties with alignment .2 the first pair of gears, a and b ,causes a reduction in the speed of the intermediate shaft proportional to the ratio of the numbers of teeth in the gears. Gear b and c are both mounted to intermediate shaft and rotate at the same speed .3 a key is used at the interface between the hub of each gear and the shaft on which it is mounted to transmit torque between the gear and the shaft .4 the second pair of gears , c and d ,further reduces the speed of gear d and the output shaft to the range of 290 rpm to 295 rpm .5 the output shaft is to carry a chain sprocket.the chain drive ultimately is to be connected to the drive wheel of the tractor.6 each of the three shafts is supported by two ball bearings .making them statically determinate and allowing the analysis of forces and stresses using standard principles of mechanics.7 the bearings are held in a housing that is to be attached to the frame of the tractor . note the manner of holding each bearing so that the inner race rotates with the shaft while the outer race is held stationary.8 seals are on the input and output shafts to prohibit contaminants from entering the housing .9 details of how the active elements are to be installed , lubricated, and aligned are only suggested at this stage of the design process to demonstrate feasibility .one possible assembly process could be as follows.Start by placing the gearing the gears, keys, spacers, and bearings on their respective shaftsThen insert input shaft into its bearing seat on the left side of the housing.Insert the left end of intermediate shaft into its bearing seat whileengaging the teeth of gears a and b.Install the center bearing support to provide support for the bearing at the right side of input shaft.Install output shaft by placing its left bearing into the seat on the center bearing support while engaging gears c and d.Install the right side cover for the housing while placing the final two bearings in their seats.Ensure careful alignment of the shafts.Place gear lubricant in the lower part of housing .The arrangement of the gears, the placement of the bearings so that they straddle the gears , and the general configuration of the housing are also design decisions . the design process cannot rationally proceed until these kinds of decisions are made . when the overall design is conceptualized, the design of the individual machine elements in the speed reducer can proceed . you should recognize that you have already made many design decisions by rendering such a sketch . first, you choose spur gears rather than helical gears , a worm and worm gear , or bevel gears. in fact , other types of speed reduction devices –belt drives , chain drives, or many others—could be appreciate.1gearsfor the gear pairs ,you must specify the number of teeth in each gear ,the pitch (size) of the teeth , the pitch diameters, the face width ,and the material and its heat treatment . these specifications depend on considerations of strength and wear of the gear teeth and the motion requirements(kinematics ). You must also recognize that the gears must be mounted on shafts in a manner that ensures proper location of the gears, adequate torque transmitting capability from the gears to the shafts (as through keys ) and safe shaft design.2shaftshaving designed the gear pairs, next you will consider the shaft design . the shaft is loaded in bending and torsion because of the forces acting at the gear teeth . thus, its design must consider strength and rigidity , and it must permit the mounting of the gears and bearings . shafts of varying diameters may be used to provide shoulders against which to seat the gears and bearings. There may be keyseats cut into the shaft, the input and output shafts will extend beyond the housing to permit coupling with the engine and the drive axle . the type of coupling must be considered, as it can have a dramatic effect on the shaft stress analysis. Seals on the input and output shafts protect internal components.3bearingsdesign of the bearings is next. If rolling contact bearings are to be used , you will probably select commercially available bearings from a manufacturer’s catalog , rather than design a unique one . you mustfirst determine the magnitude of the loads on each bearing from the shaft analysis and the gear designs. The rotational speed and reasonable design life of the bearings and their compatibility with the shaft on which they are to be mounted must also be considered. For example , on the basis of the shaft analysis, you could specify the minimum allowable diameter at each bearing seat location to ensure safe stress levels . the bearing selected to support a particular part of the shaft ,then , must have a bore( inside diameter) no smaller than necessary. When a specific bearing is selected , the shaft at the bearing seat location and allowable tolerances must be specified ,according to the bearing manufacturer’s recommendations , to achieve proper operation and life expectancy of the bearing.。
《机械工程专业英语教程》课文翻译
Lesson 1 力学的基本概念1、词汇：statics [stætiks] 静力学；dynamics动力学；constraint约束；magnetic [mæɡ＇netik]有磁性的；external [eks＇tə:nl] 外面的, 外部的；meshing啮合；follower从动件；magnitude [＇mæɡnitju:d] 大小；intensity强度，应力；non-coincident [kəu＇insidənt]不重合；parallel [＇pærəlel]平行；intuitive 直观的；substance物质；proportional [prə＇pɔ:ʃənəl]比例的；resist抵抗，对抗；celestial [si＇lestjəl]天空的；product乘积；particle质点；elastic [i＇læstik]弹性；deformed变形的；strain拉力；uniform全都相同的；velocity[vi＇lɔsiti]速度；scalar[＇skeilə]标量；vector[＇vektə]矢量；displacement代替；momentum [məu＇mentəm]动量；2、词组make up of由……组成；if not要不，不然；even through即使，纵然；Lesson 2 力和力的作用效果1、词汇：machine 机器；mechanism机构；movable活动的；given 规定的，给定的，已知的；perform执行；application 施用；produce引起，导致；stress压力；applied施加的；individual单独的；muscular [＇mʌskjulə]]力臂；gravity[ɡrævti]重力；stretch伸展，拉紧，延伸；tensile[tensail]拉力；tension张力，拉力；squeeze挤；compressive 有压力的，压缩的；torsional扭转的；torque转矩；twist扭，转动；molecule [m likju:l]分子的；slide滑动; 滑行；slip滑，溜；one another 互相；shear剪切；independently独立地，自立地；beam梁；compress压；revolve (使)旋转；exert [iɡ＇zə:t]用力，尽力，运用，发挥，施加；principle原则, 原理，准则，规范；spin使…旋转；screw螺丝钉；thread螺纹；2、词组a number of 许多；deal with 涉及，处理；result from由什么引起；prevent from阻止，防止；tends to 朝某个方向；in combination结合；fly apart飞散；3、译文：任何机器或机构的研究表明每一种机构都是由许多可动的零件组成。
美英报刊阅读教程课件 Lesson15
around the world. In the U.S., one would point his thumb up. A more recent method is to go to websites and arrange lifts beforehand, without soliciting directly from the road.
Lesson 15
1. Makeshift hitchhiking posts sprung up along the curb (Line 2, Para. 6) —路边突然出现了许多临时搭便车 站 (spring up: to suddenly appear or start to exist )
Lesson 15Fra bibliotekLesson 15
The Bronx: The Bronx is New York City’s northernmost borough. It is the only one of the city’s five boroughs situated primarily on the United States mainland rather than on an island. Brooklyn: Brooklyn, named after the Dutch city Breukelen, is New York City’s most populous borough. Brooklyn is characterized by cultural diversity, an independent art scene, distinct neighborhoods, and a unique architectural heritage. Manhattan: As commercial, financial, and cultural center of the city, Manhattan has many famous landmarks, tourist
新概念英语青少版第二册第15课The weighing machine
新概念英语青少版第二册第15课The weighing
machine
Revision Lesson 15 The weighing machine
复习课15 磅秤
Narrator： Sandy and Sue are coming home from school.
桑迪和苏正从学校回家
They meet Professor Boffin.
他们遇见了伯菲教授
Narrator： Professor Boffin is taking his coat off.
伯菲教授正在脱大衣
Sandy： What are you going to do,Professor Boffin?
伯菲教授,您干什么呀
Professor： I'm going to weigh myself,Sandy.
桑迪,我想称称体重
Sue： Where?
在哪里称
Professor： I'm going to weigh myself on this weighing machine.
就在这个磅秤上称
Professor： I'm going to put a penny in the slot.
我要把一便士塞进那个口子
There! (Sandy and Sue laugh.)
进去了 (桑迪和苏笑了起来)
Professor： What's the matter,children?
孩子们,怎么了?
Sue： You're still holding your coat,Professor Boffin! 伯菲教授,您还拿着大衣呢!。
机械工程英语课后习题答案
第一课（第9页） 2.汉翻英1. 机械工业用于制造产品的材料，可以分为金属材料、聚合物、陶瓷和复合材料。
The materials used for manufacturing products can be divided into four categories: metallics, polymerics, ceramics and composites. 2. 金属可以分为有色金属和黑色金属。
Metallics can be classified into non-ferrous and ferrous metallics. 3.塑料可以分为热固性塑料和热塑性塑料。
Plastics cab be grouped into thermosets(thermosetting plastics) and thermoplastics.4. 复合材料可以由两种或两种以上性质不同的材料组合，保留各自的特点，得到单一材料无法比拟的、优越的综合性能。
A composite consists of two more kinds of different materials, with e ach material keeping its own property, to get the superior synthetical (combined) performance which is unparalled (unmatched) by that of the individual material.5. 当其所处的工作环境变化时，智能材料能改变其性能、颜色和形状等。
An intelligent material can change its property, color, shape and so on when its working environment changes.第二课（第17页） 2. 汉翻英1. 材料的特性可分为物理特性和化学特性两大类。
机械类专业英语阅读教程部分翻译
1. Metals and Their UseIt is known that metals are very important in our life. Metals have the greatest importance for industry. All machines and other en gineering constructions have metal parts; some of them consist only of metal parts.There are two large groups of metals:1) Simple metal- more or less pure chemical elements2) Alloys -materials consisting of a simple metal combined with some other elements. About two thirds of all elements found in the earth are metals, but not all metals may be used in industry. Those metals which are used in industry are called engineering metals. The most important engineering metal is iron , which in the form of alloys with carbon and other elements, finds greater use than any other metal. Metals consisting of iron combined with some other elements are known as ferrous metals; all the other metals are called nonferrous metals. The most important nonferrous metal are copper , aluminum ,lead ,zinc ,tin , but all these metals are used much less than ferrous metals, because the ferrous metals are much cheaper. Engineering metals are used in industry in the form of alloys because the properties of alloys are much better than the properties of pure metals. Only aluminum may be largely used in the form of simple metal. Metals have such a great importance because of their useful properties or their strength, hardness, and their plasticity .Different metals are produced in different ways, but almost all the metal are found in the forms of metal ore (iron ore, copper ore, etcet cetra.)The ore is a mineral consistence of a metal combined with some impurities . In order to produce a metal from some metal ore, we must separate these impurities from the metal that is done by metallurgy .2. Plastics and Other MaterialsPlastics have specific properties which may make them preferable to traditional materials for certain uses. In comparison with metals, for example, plastics have both advantages and disadvantages. Metals tend to be corroded by inorganic acids , such as sulphuric acid and hydrochloric acid. Plastics tend to be resistant to these acids, but can have dissolved or deformed by solvent , such as carbon tetrachloride , which have the same carbon base as the plastics. Color must be applied to the surface of metals, whereas it can be mixed in with plastics. Metals are more rigid than most plastics while plastics are very light, with a specific gravity normally between 0.9 and 1.8. Most plastics do not readily conduct heat or electricity . Plastics soften slowly and can easily be shaped when they are soft.塑料具有特殊的性能。
机械工程专业英语(李光布_华中科技大学出版社)课后答案
《机械工程专业英语》翻译李光布饶锡新主编华中科技大学出版社Lesson11 numerical controlIntroductionOne of the most fundamental concepts in the area ……………………数控就是用一个穿孔的纸带或存储的程序来控制机床，美国电子工业协会对数字控制所下的定义为：“一个各项工作都有在各点上直接插入的数字来控制的系统，该系统必须至少能够自动解释这些数字中的部分。
”生产某个零件所需要的数据被称作这个零件程序数控比先前的手工操作生产更多的机械设备，数控机床能够自动的生产不同种类的零件，并且这些零件都有各种各样复杂的加工工艺过程，数字控制使得制造者们可以承担产品的加工，其产品的加工从经济的观点上看使用人工控制机床和加工过程是不太可行的的当一个孔被钻或冲出后，刀具向上撤回快速移动到下一个位置，重复这个步骤，路线沿着一个位置到另一个位置在某一方面是很重要的，他必须挑选一个是经过的时间减少、更有效（的路线）。
点对点的系统主要用于钻床、冲床和连续的铣工序中最近对DNC（现在表示分布式数字控制）的定义涵盖了“使用主计算机作为控制系统，来管理大量的带有机载微型计算机的独立的计算机数控机床”的含义。
这种系统提供了更大的存储和计算机能力来灵活的克服直接数控的缺陷。
计算机数字控制是由控制微型计算机作为机器集成的部分或某种设备一部分的系统（如机载计算机）。
零件程序由编程者事先准备好，该程序应结合由绘图软件包和加工仿真中获得的信息，从而确保零件没有程序缺陷。
机器操控者可以很容易的通过手工对机载计算机进行控制，操作者能够直接对程序进行修改，并为不同的零件制定和存储程序Lesson14 CAMTEXT1.introductionComputer-aided manufacturing involves the use of ……………………计算机辅佐制造的含义是：使用计算机和计算机技术来协助产品制造的所有环节，其中包括加工工艺和生产的辅助设计、加工、生产计划制定、管理和质量控制等！由CAD开发的数据库首先被存储，然后由CAM做进一步的处理，转化为对生产设备和材料处理设备进行操作和控制所必须的数据和命令，对产品的质量进行自动的检测和测试！CAD\CAM的出现对制造业有很大的影响，标准化生产的发展和设计努力、试验和原型工作的减少。
机械工程专业英语教程 (第5版)课件 (14)[10页]
![机械工程专业英语教程 (第5版)课件 (14)[10页]](https://img.taocdn.com/s3/m/8c97c2195acfa1c7ab00cc45.png)
Density The mass per unit volume of a substance under specified conditions of pressure and temperature
6
《机械工程专业英语教程》
Pure translation All points on the body describe parallel (rectilinear or curvilinear) paths. A reference line drawn on the body changes its linear position but does not change its angular orientation (see Fig. 15.2) .[5] 5. 物体上所有的点都沿平行（直线或曲线的） 轨迹运动。在物体上所画的一条参考线，只会 改变它的位置，而不会改变它的角度方向。
2021/1/5
《机械工程专业英语教程》
2
• Translation • Motion of a body in which every point of the body moves parallel
to and the same distance as every other point of the body; nonrotational displacement.
• into components along two axes in the plane. [4]
• 4. resolve into 意为“分解为”。全句可译为：在平面或 者二维空间，复杂运动变成了绕一个（垂直于这个平面 的）轴线的转动和同时发生的可以被分解为在这个平面
机械类专业英语阅读教程
机械类专业英语阅读教程In the realm of mechanical engineering, the language of precision and efficiency is paramount. English, as a global lingua franca, plays a crucial role in facilitating technical communication and collaboration across borders.The study of mechanical engineering is not just about understanding complex systems and their components; it also involves mastering the specialized terminology that engineers worldwide use to describe these systems. This tutorial aims to bridge the gap between the theoretical knowledge and the practical application of English in the field.Reading materials in this course have been carefully curated to reflect the diversity of topics within mechanical engineering, from basic principles to cutting-edge research. Each chapter is designed to enhance the reader's comprehension and vocabulary, while also providing insights into the latest industry trends.To truly grasp the concepts discussed in mechanical engineering texts, one must not only understand the words but also appreciate the context in which they are used. This tutorial will guide you through the nuances of technical language and help you develop the critical thinking skills necessary to interpret complex information.As you progress through the lessons, you will encountervarious types of texts, including case studies, technical specifications, and research papers. Each type requires a different approach to reading and understanding, and this course will equip you with the tools to navigate them effectively.In addition to reading comprehension, this tutorial will also focus on the development of writing skills. You will learn how to construct clear and concise sentences, organize information logically, and present your ideas persuasively.The ultimate goal of this course is to empower you with the English proficiency necessary to excel in the global mechanical engineering community. Whether you are a student, a professional, or an enthusiast, this reading tutorial will serve as a solid foundation for your journey in this dynamic field.By the end of this tutorial, you will have gained not only a deeper understanding of mechanical engineering concepts but also the ability to communicate them effectively in English. This will open doors to international opportunities and allow you to contribute to the ever-evolving world of mechanical engineering.。
(完整版)机械类专业英语课文参考翻译
第一课Text:It is known that metals are very important in our life. Metals have the greatest importance for industry. All machines and other engineering[7endVi5niEriN] constructions have metal[5metl] parts; some of them consist only of metal parts.众所周知，金属在我们的生活中是非常重要的，金属对于工业而言是有巨大的重要性，所有机器和其他工程构造都有金属零部件，其中一些还只能由金属组成。
There are two large groups of metals:1) Simple metal- more or less pure chemical elements[5elimEnt]2) Alloys[5AlCi]- materials consisting of a simple metal combined with some other elements.有两大类金属：（1）纯金属——或多或少的金属元素（2）合金——组成纯金属的原料结合其他元素。
About two thirds of all elements found in the earth are metals, but not all metals may be used in industry. Those metals which are used in industry are called engineering metals. The most important engineering metalis iron[5aiEn], which in the form of alloys with carbon[5kB:bEn] and other elements, finds greater use than any other metal. Metals consisting of iron combined with some other elements are known as ferrous[5ferEs] metals; all the other metals are called nonferrous[5nCn5ferEs] metals. The most important nonferrous metal arecopper[5kCpE], aluminum[E5lju:minEm], lead[li:d], zinc[ziNk], tin[tin], but all these metals are used muchless than ferrous metals, because the ferrous metals are much cheaper.在地球上发现的所有元素中，大约三分之二是金属元素，但是并不是所有的金属都能够用于工业上。
新版轮机英语unit15
• As tile piston moves upwards, suction takes place below the piston and liquid is drawn in the valve arrangement（阀组） ensuring that the discharge valve cannot open on the suction stroke.
• They are however complicated in construction with a number of moving parts requiring attention （注意，关心） and maintenance （维护，保养）
• When starting the pump the suction and discharge valves must be opened.
• The pump is self priming, but where possible to reduce wear or the risk of seizure（卡死） it should be flooded with liquid before starting.
• An electrically driven pump needs only to be switched（开关，电闸）, when it will run erratically（不稳定 的） for a short period until liquid is drawn into the pump 。
• Again a relief valve will be fitted between suction（吸入） and discharge chambers（排出腔）
机械专业英语 lathe
LESSON15LATHEST yped B y J ason The basic machines that are designed primarily to do turning, facing, and boring are called lathes. Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathe can do boring, facing, drilling, and reaming in addition to turning, their versatility permits several operations to be performed with a single setup of the workpiece, this account for the fact that lathes of various types are more widely used in manufacturing than any other machine tool.Lathes in various forms have existed for more than two thousand years .modern lathes date from about 1797, when Henry Maudsley developed one with a leadscrew. it provided controlled , mechanical feed of the tool . This ingenious Englishman also developed a change-gear system that could connect the motions of the spindle and leadscrew and thus enable thread to be cut.LATHE CONSTRUCTION. The essential components of a lathe are developed in the block diagram of fig.15-1. These are the bed, headstock assembly, tailstock assembly, carriage assembly, quick-change gear box, and the leadscrew and feed rod.The bed is the backbone if a lathe. It is usually made of well-normalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted v-shape for all four ways, whereas others utilize one inverted v and one flat way in one or both sets. Because several other components are mounted and/or move on the ways they must be made with precision to assure accuracy of alignment. Similarly, proper precaution should be taken in operating a lathe to assure the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The ways on most modern lathes surface hardened to offer greater resistance to wear and abrasion.The headstock is mounted in a fixed position on the inner ways at one end of the lathe bed. It provides a powered means of rotating the work at various speeds. It consists, essentially, a hollow spindle, mounted in accurate bearings, and a set of transmission gears---similar to a truck transmission---through the spindle can be rotated at a number of speeds. Most lathes provide from eight to eighteen speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. A longitudinal hole extends through the spindle so that long bar stock can be fed through it. This size of this hole is an important size dimension of a lathe because it determines the maximum size of the bar stock that can be machined when the material must be fed through the spindle.This inner end of the spindle protrudes from the gear box and contains a means for mounting various types of chucks, face plates, and dog plates on it. Whereas small lathes often employ a threaded section to which the chucks are screwed, most large lathes utilize either cam-lock or key-drive taper noses. These provide a large-diameter taper that assures the accurate alignment of the chuck, and a mechanism that permits the chuck of the face plate to be locked or unlocked inposition without the necessity of having to rotate these heavy attachments.Power is supplied to the spindle by means of an electric motor through a v-belt or silent-chain drive. Most modern lathes have motors of from 5 to 15 horsepower to provide adequate power for carbide and ceramic tools at their high cutting speeds.The tailstock assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it on some type of keyed ways. This transverse motion permits aligning the tailstock and headstock spindle and provides a method of turning tapers. The third major component of the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 2 to 3 inches in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a handwheel and screw. The open end of the quill hole terminates in a Morse taper in which a lathe center, or various tools such as drills, can be held. A graduated scale, several inches in length, usually is engraved on the outside of the quill to aid in controlling its motion in and out of the upper casting. A locking device permits clamping the quill in any desired position.The carriage assembly provides the means for mounting and moving cutting tools. The carriage is a relatively flat H-shaped casting that rests and moves on the outer set of ways on the bed. The transverse bar of the carriage contains ways on which the cross slide is mounted and can be moved by means of a feed screw that is controlled by a small handwheel and a graduated dial. Through the cross slide a means is provided for moving the lathe tool in the direction normal to the axis of the work.On most lathes the tool post actually is mounted on a compound rest. This consists of a base, which is mounted on the cross slide so that it can be pivoted about a vertical axis, and an upper casting. The upper casting is mounted on ways on this base so that it can be moved back and forth and controlled by means of a short lead screw operated by a handwheel and a calibrated dial.Manual and powered motion for the carriage, and powered motion for the cross slide, is provided by mechanisms within the apron, attached to the front of the carriage. Manual movement of the carriage along the bed is effected by turning a handwheel on the front of the apron, which is geared to a pinion on the back side. This pinion engages a rack that is attached beneath the upper front edge of the bed in an inverted position.To impart powered movement to the carriage and cross slide, a rotating feed rod is pivoted. The feed rod, which contains a keyway throughout most of its length, passes through the two reversing bevel pinion and is keyed to them. Either pinion can be brought into mesh with a mating bevel gear by means of the reversing lever on the front of the apron and thus provide “forward” or “reverse” power to the carriage. Suitable clutches connect either the rack pinion or the cross-slide screw to provide longitudinal motion of the carriage or transverse motion of the cross slide.For cutting threads, a second means of longitudinal drive is provided by a lead screw. Whereas motion of the carriage when driven by the feed-rod mechanism takes place through a friction clutch in which slippage is possible, motion through the lead screw is by a direct, mechanical connection between the apron and the lead screw. This is achieved by a split nut. By means of a clamping lever in the front of the apron, the split nut can be closed around the lead screw. With the split nut closed, the carriage is moved along the lead screw by direct drive without possibility of slippage.Modern lathes have a quick-change gear box. The input end of this gear box is driven fromthe lathe spindle by means of suitable gearing. The output end of the gear box is connected to the feed rod and lead screw. Thus, through this gear train, leading from the spindle to the quick-change gear box, thence to the lead screw and feed rod, and then to the carriage, the cutting tool can be made to move a specific distance, either longitudinally or transversely, for each revolution of the spindle. A typical lathe provides, through the feed rod, forty-eight feeds ranging from 0.002 inch to 0.118 inch per revolution of the spindle, and, through the lead screw, leads for cutting forty-eight different threads from 1.5 to 92 per inch. On some older and some cheaper lathes, one or two gears in the gear train between the spindle and the change gear box must be changed in order to obtain a full range of threads and feeds.。
机械专业英语阅读教程
机械专业英语阅读教程Mechanical engineering is a field that requires a solid understanding of both theoretical principles and practical applications. The study of mechanical engineering in Englishis essential for students who wish to engage with the global community of engineers and researchers. This tutorial aims to provide a comprehensive guide to reading mechanical engineering materials in English, focusing on key concepts, terminology, and strategies for effective learning.Introduction to Mechanical Engineering ReadingMechanical engineering encompasses a wide range of topics, from dynamics and thermodynamics to materials science and control systems. Reading materials in this field ofteninclude textbooks, research papers, and technical manuals. To effectively read and understand these materials, it'simportant to have a strong foundation in English vocabulary and grammar specific to the field.Understanding TerminologyOne of the first steps in mastering mechanicalengineering reading is to become familiar with thespecialized terminology. Terms such as 'kinematics','statics', 'mechanical systems', and 'fluid dynamics' are common and must be understood to grasp the concepts discussed in texts. Building a glossary of terms and regularlyreviewing them can be beneficial.Reading Strategies1. Pre-reading: Before diving into the text, scan through the headings, subheadings, and any illustrations to get a general idea of the content.2. Active Reading: Engage with the text by taking notes, underlining key points, and summarizing sections in your own words.3. Critical Reading: Analyze the author's arguments and the evidence presented. Consider the implications of the information and how it relates to other concepts you've learned.4. Post-reading: Reflect on the material by discussing it with peers or writing a summary. This helps consolidate your understanding.Technical Writing SkillsUnderstanding how to read mechanical engineering texts also involves recognizing the structure and style oftechnical writing. This includes:- Abstracts: Brief summaries of research papers that highlight the main findings.- Introductions: Sections that provide backgroundinformation and the purpose of the study.- Methods: Descriptions of how experiments or studies were conducted.- Results: Presentation of data and findings.- Discussion: Analysis of the results and their significance.- Conclusions: Summaries of the study's implications and suggestions for future research.Using Reference MaterialsReference materials such as dictionaries, encyclopedias, and online resources are invaluable when reading in English. They can provide definitions, examples, and further explanations of concepts and terms.Building VocabularyA robust vocabulary is crucial for reading comprehension. Regularly learn new words and their usage in context. Flashcards, vocabulary apps, and word-a-day calendars can be useful tools.Practice and ApplicationThe more you read, the better you become. Apply whatyou've learned by discussing mechanical engineering topics inEnglish, writing summaries, and participating in online forums.ConclusionReading mechanical engineering materials in English is a skill that can be developed with practice and dedication. By understanding the terminology, employing effective reading strategies, and utilizing reference materials, students can enhance their comprehension and contribute meaningfully to the global mechanical engineering community.。
机械英语综合教程Lesson 15 Laser Technology)
与普通光相比，激光 有许多特性，例如空 间分布、光束发散、 聚焦、暂时性、亮度、 功率等等。
由于激光的这些特性， 尤其是空间分布、聚 焦和功率，在激光加 工中具有重要意义， 接下来介绍几种重要 的应用。
• • Drilling • • Drilling is one of the important applications of the laser machining. In early investigations pulsed ruby ( • [ˈru:bi] ) lasers were used for piow • the usefulness of the ruby laser in drilling holes in many materials is discussed. The location of the hole • to be drilled could be precisely located, and large rations of depthto-diameter of hole could be obtained.
Big mind
激光加工 激光加工的基本原理 是近期才发现的。 激光这个词是其英语 表达light amplification by simulated emission radiation的首字母缩写， 意为“模拟辐射使光 放大”。 激光加工过程是依靠 密集的、高度定向的、 相干性的单色光与工 件的相互作用，使工 件材料以气化的方式 去除。
有一种现象叫做“光管效 应”，常见于激光打孔中。 光管效应的状况会影响孔 的外形。 这个效应的出现是由于当 孔很深时，激光的内部产 生反射。 通常激光聚焦在孔的表面。 接着进入孔后发散，并且 由于入射角很小，孔壁使 激光反射。 与其他加工方法相反，每 次脉冲以后，要进行一系 列的努力重新聚焦，以获 得更深的孔。
高三英语上学期unit-15-integrating-skill
三叶罗茨鼓风机组装与维修更换电机图文说明教程本经验主要介绍罗茨风机结构组成、安装、维修、更换电机、现场安装要求等内容。 罗茨风机机组由罗茨风机主机、电机、进口消声器、出口消声器、底座、弹性接头、单向阀、护轮罩、上海自动化仪表四厂、安全阀、传动装置等组成。扳手、直线尺罗茨风机的组装与维修1、将底座置于平整地面，风机主机轻放于底座风机侧，风机与底座连接孔对齐后，选用适合的工具将配套 汽轮机辅机设备的联锁保护试验分享给大家
1、在下列条件下禁止启动： 2、保安系统，调速系统，自动主汽门动作失灵或关闭不严。 3、汽轮机组动静部分有明显摩擦声。 4、任一油泵工作失常或任一轴承无回油及油量明显减少。 5、主要表计失灵（转速表、轴向位移表、排气上海自动化仪表四厂、主汽上海自动化仪表四厂、主汽温度表、润滑油温度表等）。 6、盘车装置失灵。 7、调速系统不能维持空负荷或甩掉全负荷而转速不能维持在危急保安器动作转速以内时。 8、排汽安全阀卡涩或动作值不符合规定时。 9、油箱油位低于低限或油质不合格。 不锈钢上海自动化仪表四厂使用事项不锈钢上海自动化仪表四厂具有良好的抗振性能，特别适用于有机械振动和介质脉动的工作环境适用于测量对铜及铜合金，或不锈钢合金不起腐蚀作用气体，液体的压力。不锈钢上海自动化仪表四厂由导压系统（包括接头、弹簧管、限流螺钉等）、齿轮传动结 采用icr18Ni9T、Ocr18Ni12Mo2Ti、sus316，结构为全密封型，具有较强的防被测介质腐蚀和抗环境腐蚀的能力。 1、 1)径向直接安装 2)径向带后边 3)轴向直接安装 4)轴向带前边 2、 外形尺寸：单位：mm Dd0d1H1H2LL1L2接头螺纹d60764.5≤60143666M14x1.5；Z1/4,1/4NPT1001164.8≤100≤35205098M20x15；Z1/2;Z1/4,1/2NPT,1/
新概念英语第四册自学导读：第十五课工业中的秘密（上）
Lesson 15 Secrecy in industry第⼗五课⼯业中的秘密by J.D. BERNALfrom The Social Function of Science15-1. Two factors weigh heavily against the effectiveness of scientific research in industry.【译⽂】两种因素严重妨碍⼯业⽅⾯的科研效率。
【单词和短语】weigh：有分量，具有重要性，有影响（to influence someone’s opinion and the decision that they make），例如：Such recommendations will weigh in his favour.这种推荐对他⼤有裨益。
The lady’s evidence weighed heavily against him.⼥房东的证词对他极为不利。
Selfish interests don’t weigh with him at all.他根本不把私利置于⼼上。
15-2. One is the general atmosphere of secrecy in which it is carried out, the other the lack of freedom of the individual research worker.【译⽂】⼀是普遍的保密⽓氛，科研就是在这种⽓氛中进⾏的；⼆是个体的研究⼈员缺乏⾃由。
【讲解】it指scientific research。
the other the lack of…中other后省略了is。
【单词和短语】secrecy：秘密，秘密状态，保密（the process of keeping something secret, or when something is kept a secret），例如：do sth. with great secrecy 极秘密地做某事practise secrecy 保密The mayor stressed the necessity of absolute secrecy.市长强调必须绝对保密。