機械工程專業(yè)英語課件

本文格式為Word版，下載可任意編輯——機械工程專業(yè)英語課件EnglishechanicalEngineering機械工程專業(yè)英語SlottedconepointedsetscrewHexnutSlottednutBrightwasherSpringwasherTabwasher錐端緊定螺釘六角螺母六角槽形螺母平墊圈彈簧墊圈外舌止動墊圈HexagonheadboltStudSlottedcheeseheadscrewSlottedpanheadscrewSlottedcountersunkscrewHexagonsocketcap六角頭螺釘雙頭螺柱頭圓柱頭螺釘盤頭螺釘沉頭螺釘圓柱頭內(nèi)六角螺釘Typesofscrewfasteners螺紋緊固件的種類PartswiththreadsusedforjoiningandfasteningarecalledscrewfastenersThemostwidelyusedcomponentsasscrewfastenersareboltsdoublescrewboltsstudscrewsnutsandwashers用螺紋聯(lián)接并起緊固作用的零件稱為螺紋緊固件常用的螺紋緊固件有螺栓雙頭螺柱螺釘螺母墊圈等Lesson19Screwsfastenersandjoints機械工程專業(yè)英語機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsBoltedjointsareoneofthemostcommonelementsinconstructionandmachinedesignTheyconsistofcapscrewsorstudsthatcaptureandjoinotherpartsandaresecuredwiththematingofscrewthreadsTherearetwomaintypesofboltedjointdesignsInonetheboltistightenedtoacalculatedclamploadusuallybyapplyingameasuredtorqueloadThejointwillbedesignedsuchthattheclamploadisneverovercomebytheforcesactingonthejointandthereforethejoinedpartsseenorelativemotionTheothertypeofboltedjointdoesnothaveadesignedclamploadbutreliesontheshearstrengthoftheboltshaftThismayincludeclevislinkagesjointsthatcanmoveandjointsthatrelyonlockingmechanismlikelockwashersthreadadhesivesandlocknuts機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsBoltedjointScrewjointStudjointBolt螺栓Theboltassemblyisusedwhenjointpartsarenottoothicktodrillthroughholes螺栓用于聯(lián)接二通孔薄件Stud雙頭螺柱Studareusedinsituationswhereapartwithathroughholeandapartwithblindtappedhole雙頭螺柱用于聯(lián)接一通孔薄件和一盲孔厚件Screw螺釘Screwsaremostlyusedforthecaseswithsmallbearingforcessuchasinspectioncoverswhichhavetoberemovedfrequently螺釘多用于用于受力不大需要經(jīng)常拆卸的處境Nut螺母Nutareusedtomatchtheotherscrewfasteners螺母與其他螺紋件合作使用Washer墊圈彈簧墊圈平墊圈Washerareusedtomatchtheotherscrewfasteners墊圈與其他螺紋件合作使用機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheclamploadalsocalledpreloadofacapscrewiscreatedwhenatorqueisappliedandisgenerallyapercentageofthecapscrewsproofstrengthCapscrewsaremanufacturedtovariousstandardsthatdefineamongotherthingstheirstrengthandclamploadTorquechartsareavailablethatidentifytherequiredtorqueforcapscrewsbasedontheirpropertyclassorgradeWhenacapscrewistighteneditisstretchedandthepartsthatarecapturedarecompressedTheresultisaspringlikeassemblyExternalforcesaredesignedtoactonthepartsthathavebeencompressedandnotonthecapscrew機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultisanonintuitivedistributionofstraininthisengineeringmodelaslongastheforcesactingonthecompressedpartsdonotexceedtheclamploadthecapscrewdonotseeanyincreasedloadThismodelisonlyvalidwhenthemembersundercompressionaremuchstifferthanthecapscrewThisisasimplifiedmodelInrealitytheboltwillseeasmallfractionoftheexternalloadpriortoitexceedingtheclamploaddependingonthecompressedpartsstiffnesswithrespecttothehardwaresstiffness機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultsofthistypeofjointdesignareGreaterpreloadsinboltedjointsreducethefatigueloadingofthehardwareForcyclicloadstheboltdoesnotseethefullamplitudeoftheloadAsaresultfatiguelifecanbeincreasedorifthematerialexhibitsanendurancelimitextendedindefinitelyAslongastheexternalloadsonajointdontexceedtheclamploadthehardwaredoesntseeanymotionandwillnotcomeloosenolockingmechanismsarerequiredInthecaseofthecompressedmemberbeinglessstiffthanthehardwaresoftcompressedgasketsforexamplethisanalogydoesntholdtrueTheloadseenbythehardwareisthepreloadplustheexternalload機械工程專業(yè)英語預備學識一BackgroundinationLesson19Screwsfastenersandjoints機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultsofthistypeofjointdesignareGreaterpreloadsinboltedjointsreducethefatigueloadingofthehardwareForcyclicloadstheboltdoesnotseethefullamplitudeoftheloadAsaresultfatiguelifecanbeincreasedorifthematerialexhibitsanendurancelimitextendedindefinitelyAslongastheexternalloadsonajointdontexceedtheclamploadthehardwaredoesntseeanymotionandwillnotcomeloosenolockingmechanismsarerequiredInthecaseofthecompressedmemberbeinglessstiffthanthehardwaresoftcompressedgasketsforexamplethisanalogydoesntholdtrueTheloadseenbythehardwareisthepreloadplustheexternalload機械工程專業(yè)英語預備學識一BackgroundinationLesson19ScrewsfastenersandjointsThreadstrengthNutthreadsaredesignedtosupporttheratedclamploadoftheirrespectiveboltsIftappedthreadsareusedinsteadofanutthentheirstrengthneedstobecalculatedSteelhardwareintotappedsteelthreadsrequiresadepthof15threaddiametertosupportthefullclamploadIfanappropriatedepthofthreadsisnotavailableorthethreadsareinaweakermaterialthanthecap