机械工程专业英语-交流与沟通EnglishCommunicationforMechanicalEng

Part1:IntroductiontoMechanicalEngineering1.1Introduction1.1.1Whatisengineering?Engineeringisthepracticalandcreativeapplicationofscienceandmathematicstosolveproblems.—Problem-solvingOnewhopracticesengineeringiscalledanengineer.Anengineeris:aninnovator,planner,andproblem-solverofoursociety.NOTE:theworkofanengineerdiffersfromthatofascientist.Engineeringservesasthebridgebetweenscientificdiscovery,commercialapplication,andbusinessmarketing.1.1.2MainbranchesofengineeringChemicalengineeringCivilengineeringElectricalengineeringMaterialengineeringMechanicalengineeringFigure1.1percentagesofengineersworkinginvariousengineeringfieldsMechanicalengineeringisthesecond-largestfieldamongthetraditionalengineeringdisciplinesandisperhapsthemostgeneral.1.2MechanicalEngineeringMechanicalengineeringisadisciplineofengineeringthatappliestheprinciplesofphysicsandmaterialsscienceforanalysis,design,manufacturing,andmaintenanceofmechanicalsystems.Mechanicalengineeringisallaboutmakingusefulmachines.Basicknowledge:mechanics,kinematics,thermodynamics,materialsscience,andstructuralanalysis..Basictools:computer-aidedengineeringandproductlifecyclemanagement1.3CommonTraitsofGoodEngineers•problemsolvers；•firmgraspofthefundamentalprincipalofengineering；•analytical,detailedoriented,andcreativepeople；•lifelonglearners；•well-trainedengineerscanworkwellinotherrelatedfields；•havegoodwrittenandoralcommunicationskills；•havetime-managementskills；•havegood“peopleskills”；•beadeptatusingcomputerstosolvepracticalproblems.1.4Whatisamachine?Whatisamachine?MachinesComplicatedmachinesSimplemachines•activelyparticipateinprofessionalmeetings；•Goodcross-cultureinterpersonalandcommunicationskills；Simplemachines：NailclippersSimplekitchenmachines—abottleopenerComplicatedmachines：excavatorscarsWhatisamachine?•Acombinationofmanyinterconnectedparts•PerformdesiredworkaccompaniedbydesiredmotionsAccordingtoFranzReuleaux'sdescription“Amachineisacombinationofresistantbodies,sointerconnectedthatbyapplyingforceormotiontooneormoreofthosebodies,someofthosebodiesarecausedtoperformdesiredworkaccompaniedbydesiredmotions.”1.5Howtodefineanddescribeamachine?Question:Howamachineisdescribedinengineering?（languagesofshapeandsizedescription)Engineeringdrawing3D2DViewsAssemblydrawingsOrthographicdrawingDescribedetailsofapartDescribetheshapeofamachineAnuniversaltechnicallanguageWorkingdrawingsDetailworkingdrawings1.5.1EngineeringDrawingsDrawingsconveythefollowingcriticalinformation:Tolerances–theallowablevariationsforeachdimension.Geometry–theshapeoftheobject;representedasviews;howtheobjectwilllookwhenitisviewedfromvariousangles,suchasfront,top,side,etc.Dimensions–thesizeoftheobjectiscapturedinacceptedunits.Finish–specifiesthesurfacequalityoftheitem,functionalorcosmetic.Material–representswhattheitemismadeof.1.5.2DraftingStandardsForuniformity,thedrawingsmustbedrawnaspercertainstandardpractice.Drawingpracticemustfollowcertainrules,ifitistoserveasameansofcommunication.1.SheetsizesandlayoutTable1.1Sheetsizes1.SheetsizesandlayoutFigure1.3.Layoutofsheet2.ScalesThescaleistheratiobetweenthemeasurementonthedrawingandtheactualsize.ListedinTable1.2arethesalesusedintechnicaldrawing.Table1.2ScalesNote:Itispermissibletochoosethescalesshowninbrackets,ifnecessary.Whateverscaleisused,thedimensionsonthedrawingindicatethetruesizeoftheobject,notoftheview.3.TypesofLinesFigure1.4Typesoflines1.5.3Views1.Theorthographicprojection2.MultipleviewsTheobjectisprojectedontosixplanesrespectively—sixprincipleviewsUnfoldsixplanesintoasingleplanefronttopbottomLHUpDownLRFBRLFrontTopBottomLeftRightBackLFigure1.7Sixprincipleviews.3.AuxiliaryviewsAnauxiliaryviewisanorthographicviewthatisprojectedintoanyplaneotherthanoneofthesixprincipalviews.Theseviewsaretypicallyusedwhenanobjectcontainssomesortofinclinedplane.Figure1.8AuxiliaryviewFigure1.9Isometricview4.SectionViewsSectionviewsareprojectedviews(eitherAuxiliaryorOrthographic)whichshowacrosssectionofthesourceobjectalongthespecifiedcutplane.Figure1.10SectionviewsFullSectionHalfSectionOffsetSectionRevolvedSectionRemovedSectionBroken-outSectionInassemblydrawings,solidpartsaretypicallynotsectionedwhenacuttingplanepassesthroughtheirlongitudinalaxis.1.5.4WorkingDrawings1.DetailworkingdrawingsWorkingDrawingsprovidethecompletesizeandshapedescriptionofapartorgroupofpartssothatthepartcanbemanufacturedaccordingtospecificationorassembledinthecorrectsequence.Thedetailworkingdrawingdelineatestheexactshapeandsizeofanindividualpart.GeometrictoleranceTechnicalrequirementsinnotesToleranceSurfaceroughnessFigure1.12ThedetailworkingdrawingofaspurgearDimensionsViewsTitleblockTableofparameters2.AssemblydrawingsAnassemblydrawingshowsaproductcompletelyputtogetherandsuppliestheinformationaboutthelocationandrelationshipoftheparts.Figure1.13Isometricassemblyofamentalbenchvice.Figure1.14Explodedisometricassemblydrawingofagearpump.1.5.5Feature-Based3DModels3Dfeature-basedCADmodelswiththeembeddedparametricandassociatecapability,iswidelyusedinmechanicaldesign.Figure1.15(a)3DCADmodelsofplasticinjection