机械专业英语课件.pptx
Terminology2022-4-201机械工程专业英语教程 Nut A small block of metal with a central, threaded hole that is designed to fit around and secure a bolt or screw. 螺母，螺帽：中部有带螺纹的孔, 用于与螺栓或螺钉相配合并将其紧固的小金属块。机械工程专业英语教程2022-4-20Rivet A rivet is a metal pin with a head used to fasten two or more materials together.铆钉：铆钉是一头有帽的金属钉，用来将两种或多种材料紧固在一起。 2 Spring An elastic device, that regains its original shape after being compressed or extended 弹簧: 一种弹性装置在被压缩和拉伸后仍能恢复原来的形状。2022-4-20机械工程专业英语教程3机械工程专业英语教程2022-4-20fastener: 紧固件，连接件紧固件，连接件modular: 模数的，制成标准件的，预制的，模数的，制成标准件的，预制的，组件的组件的subassembly:组件，部件，局部装配，组件组件，部件，局部装配，组件装配装配 4机械工程专业英语教程2022-4-20cotter:栓，开口销，楔；用销子固定栓，开口销，楔；用销子固定Cotter pin: 扁销，开口销扁销，开口销bumper:保险杠，缓冲器，阻尼器，减震器保险杠，缓冲器，阻尼器，减震器 5机械工程专业英语教程2022-4-20silicon: 硅硅brass: 黄铜黄铜bronze 青铜青铜beryllium:铍铍 6机械工程专业英语教程2022-4-20helical:螺线，螺旋线，螺纹螺线，螺旋线，螺纹temper: 回火回火corrosion:腐蚀，侵蚀，锈蚀腐蚀，侵蚀，锈蚀 7Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 Fasteners are devices which permit one part to be jointed to a second part and，hence，they are involved in almost all designsThe acceptability（满意程度）of any product depends not only on the selected components，but also on the means by which they are fastened togetherThe principal purposes of fasteners are to provide the following design features：Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧（l）Disassembly（拆卸） for inspection and repair；（2）Modular design（模块化设计） where a product consists of a number of subassemblies（组件）Modular design aids manufacturing as well as transportation Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧lRemovable (可拆式)This type permits the parts to be readily disconnected without damaging the fastener. An example is the ordinary nut-and-bolt fastener.There are three main classifications of fasteners，which are described as follows：Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧2Semipermanent半永久式For this type，the parts can be disconnected，but some damage usually occurs to the fastenerOne such example is a cotter pin (开口销)Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧3Permanent永久式When this type of fastener is used，it is intended that the parts will never be disassembledExamples are riveted and welded joints (铆接和焊接)Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 The following factors should be taken into account when selecting fasteners for a given application：（1）primary function;（2）appearance;（外部特征）（3）a large number of small size fasteners versus a small number of large size fasteners（an example is bolts）；Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧（4）operating conditions such as vibration，loads and temperature;（5）frequency of disassembly；（6）adjustability in the location （位置）of parts;（7）types of materials to be joined；（8）consequences（后果） of failure or loosening of the fastenerLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 The importance of fasteners can be realized (认识) when referring to（涉及） any complex productIn the case of the automobile，there are literally (逐字的，照字面的) thousands of parts which are fastened together to produce the total productLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧The failure or loosening of a single fastener could result in a simple nuisance（障碍，损失，麻烦）such as a door rattle（喀啦声） 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 fastener for the specific application.Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 Springs are mechanical members which are designed to give a relatively large amount of elastic deflection under the action of an externally applied loadHookes law，which states that deflection is proportional to load, is the basis of behavior of springsLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧However，some springs are designed to produce a nonlinear relationship between load and deflectionThe following is a list of the important purposes and applications of springs:Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧1Control of motion in machinesThis category represents the majority of spring applications such as operating forces in clutches and brakes（离合器和制动器）Also，springs are used to maintain contact between two members such as a cam and its followerLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧2. Reduction of transmitted forces as a result of impact（冲击）or shock loading. Applications here include automotive suspension system springs and bumper springs（缓冲弹簧）.Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧3Storage of energyApplications in this category are found in clocks, movie cameras（摄影机）and lawn mowers（割草机）. Many parking meters （停车计时器）use spring mechanisms（弹簧机构）which perform the timing function.4. Measurement of force. Scales（秤）used to weigh people is a very common application for this category.Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 Most springs are made of steel, although silicon bronze, brass and beryllium copper（硅青铜、黄铜和铜铍合金）are also used. Springs are universally made by companies which specialize in the manufacture of springs. Lesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧The helical（螺旋线） coil spring（圆柱螺旋弹簧）is the most popular type of spring; torsion bars and leaf springs（扭杆和板弹簧）are also widely used. If the wire diameter（assuming a helical coil spring）is less than 8mm, the spring will normally be coldwound（冷卷法） from harddrawn（拔） or oiltempered（回火） wire. For large diameters, springs are formed using hotrolled barLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧 It is good practice to consult（咨询） with a spring manufacturing company when selecting a spring design，especially if high loads or temperatures are to be encountered，or if stress reversals occur or corrosion resistance （抗蚀）is requiredLesson 7 Fasteners and Springs 紧固件和弹簧紧固件和弹簧To properly select a spring，a complete study of the spring requirements，including space limitations，must be undertakenMany different types of special springs are available to satisfy unusual requirements or applications
