EnglishinMechanicalEngineeringUnit 4 Mechanical Design and Theory
English in Mechanical Engineering Unit 4 Mechanical Design and Theory
MAINCONTENTSOFTHECHAPTER 4.1Different types of mechanical design problems 4.2Machineelements in mechanical design 4.3Friction,Wear and Lubrication4.4IndustrialRobot
4.1 Different types of mechanical design problems 4.2 Machine elements in mechanical design 4.3 Friction, Wear and Lubrication 4.4 Industrial Robot MAIN CONTENTS OF THE CHAPTER
MAINCONTENTSOFTHECHAPTER 4.1Different types of mechanical design problems 4.2 Machine elements in mechanical design 4.3Friction,Wear and Lubrication4.4IndustrialRobot
4.1 Different types of mechanical design problems 4.2 Machine elements in mechanical design 4.3 Friction, Wear and Lubrication 4.4 Industrial Robot MAIN CONTENTS OF THE CHAPTER
4.1Differenttypes of mechanical design problems? 4.1.1Selection Design4.1.2Configuration Design4.1.3Parametric Design4.1.4OriginalDesign?4.1.5Redesign4.1.6VariantDesign4.1.7ConceptualDesign andProduct Design
4.1.1 Selection Design 4.1.2 Configuration Design 4.1.3 Parametric Design 4.1.4 Original Design 4.1.5 Redesign 4.1.6 Variant Design 4.1.7 Conceptual Design and Product Design 4.1 Different types of mechanical design problems
4.1.1 Selection DesignConsiderthefollowingexampleTheshafthasadiameterof20mm（0.787in).轴的直径为20mmThere is a radial force of 6675N on the shaft at the bearing,and the shaft rotates at amaximumof2000rpm轴承轴的径向力为6675N，最大转速为2000rpmTab,4-1 Potential bearings for a shaffOutsideLoadCatalogSpeeddiameter (mm)Width (mm)Bimit (rpm)Typetating (lb)number记15015.08456204Barrne22390063049000Beanne7073811903.00agular-conta:Shaft6675 NRaller2131：:0022093502000rpmeacing241193013,000208Vecfli280013,000arinl23VariableNylon290104930bushing500Fig.4-1.Load on a shaft
4.1.1 Selection Design Consider the following example. The shaft has a diameter of 20 mm (0.787 in). 轴的直径为20mm There is a radial force of 6675N on the shaft at the bearing, and the shaft rotates at a maximum of 2000 rpm. 轴承轴的径向力为6675N，最大转速为2000rpm
4.1.2ConfigurationDesignThebodyoftheMERismadeupofaRoverEquipmentDeck(RED)whereall the experiments are mounted,a Rover Electronics Module (REM), anInertial Measurement Unit (IMU), a Warm Electronics Box (WEB), a battery, aUHF radio, an X-band telecom HW, and a Solid-State Power Amplifier (SSPA)DMUDMER的主体由Rover设备甲板（RED）UHFradioREM（所有实验均在此基础上进行）Rover电子模块（REM），惯性测量单ebmmH元（IMU），加热电子盒子（WEB），电Bat池，超高频无线电X波段电信HW和Fronr固态功率放大器（SSPA）构成。WEESSPAFig.4-2.Themajorassemblies intheMER
4.1.2 Configuration Design The body of the MER is made up of a Rover Equipment Deck (RED) where all the experiments are mounted, a Rover Electronics Module (REM), an Inertial Measurement Unit (IMU), a Warm Electronics Box (WEB), a battery, a UHF radio, an X-band telecom HW, and a Solid-State Power Amplifier (SSPA) MER的主体由Rover设备甲板(RED) （所有实验均在此基础上进行）、 Rover电子模块(REM)，惯性测量单 元(IMU)，加热电子盒子(WEB)，电 池，超高频无线电，X波段电信HW和 固态功率放大器(SSPA)构成
4.1.3ParametricDesignExample:We wantto designacylindrical storagetank that must hold 4 m3ofliquid.我们想设计一个可以容纳4m3液体的圆柱形储罐。This tank is described by the parameters r, its radius, and l, its length and itsvolumeisdeterminedby罐的半径、长度和体积可描述为V=元r21Givenavolumeequal to4m3,thenr21=1.273Manyparameters-thenumber of rollers,theirpositions,theshape ofthebaffles除以上参数外，包括滚筒的数量、位置、挡板的形状等参数仍需进一步设计
4.1.3 Parametric Design Example: We want to design a cylindrical storage tank that must hold 4 m3 of liquid.我们想设计一个可以容纳4m3液体的圆柱形储罐。 This tank is described by the parameters r, its radius, and l, its length and its volume is determined by 罐的半径、长度和体积可描述为 Given a volume equal to 4 m3 , then Many parameters - the number of rollers, their positions, the shape of the baffles 除以上参数外，包括滚筒的数量、位置、挡板的形状等参数仍需 进一步设计
4.1.4OriginalDesignInmanywaystheothertypes ofdesign problemsselection,configuration,and parametric are simply constrained subsets of an original design.在许多方面，其他类型的设计问题包括选择、配置和参数等只是原始设计的约束子集。Thepotential solutions are limited to alist, anarrangement of components.or a set of related characterizing values. Thus, if we have a clearmethodology for performing original design, we should be able to solve anydesignproblem withamorelimited setofpotential solutions潜在的解决方案仅限于列表、组件的排列或一组相关的特征值。因此，如果我们有一个清晰的方案来执行原始设计，我们应该能够用一组更有限的潜在解决方案来解决任何设计问题
4.1.4 Original Design In many ways the other types of design problems — selection, configuration, and parametric— are simply constrained subsets of an original design. 在许多方面，其他类型的设计问题包括选择、配置和参数等只是原始设计 的约束子集。 The potential solutions are limited to a list, an arrangement of components, or a set of related characterizing values. Thus, if we have a clear methodology for performing original design, we should be able to solve any design problem with a more limited set of potential solutions. 潜在的解决方案仅限于列表、组件的排列或一组相关的特征值。因此 ，如果我们有一个清晰的方案来执行原始设计，我们应该能够用一组 更有限的潜在解决方案来解决任何设计问题
4.1.5RedesignExample:Thebasic configuration ofthebicycle-the twotensioned,spokedwheels of equal diameter, the diamond-shaped frame,and the chain drive自行车的基本结构：两个拉紧的、等径的轮、菱形框架和链传动。Fig.4-3.1890HumberbicycleFig.4-4.Ottodicycle
4.1.5 Redesign Example: The basic configuration of the bicycle—the two tensioned, spoked wheels of equal diameter, the diamond-shaped frame, and the chain drive 自行车的基本结构：两个拉紧的、等径的轮、菱形框架和链传动
4.1.5Redesign(1)betterabletohandleroughterrainthantraditionalbikes.比传统自行车更能适应崎呕的地形。(2)Second,thereis improved understandingof humancomfort,ergonomics,andsuspensions其次，对人体舒适、人体工程学和悬吊的理解有所提高。(3)Third, customers are always looking for somethingnewand exciting even if performance is not greatlyimproved.第三，客户总是在寻找新的和令人兴奋的东西，即Fig.4-5.MarinMountvision使性能没有得到很大的改善。(4)Fourth,materials and components have improved第四，材料和部件得到了改进
4.1.5 Redesign (1) better able to handle rough terrain than traditional bikes. 比传统自行车更能适应崎岖的地形。 (2) Second, there is improved understanding of human comfort, ergonomics, and suspensions. 其次，对人体舒适、人体工程学和悬吊的理解有所 提高。 (3) Third, customers are always looking for something new and exciting even if performance is not greatly improved. 第三，客户总是在寻找新的和令人兴奋的东西，即 使性能没有得到很大的改善。 (4) Fourth, materials and components have improved 第四，材料和部件得到了改进