機(jī)械工程專(zhuān)業(yè)英語(yǔ)課件

本文格式為Word版，下載可任意編輯——機(jī)械工程專(zhuān)業(yè)英語(yǔ)課件EnglishechanicalEngineering機(jī)械工程專(zhuān)業(yè)英語(yǔ)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(dòng)墊圈HexagonheadboltStudSlottedcheeseheadscrewSlottedpanheadscrewSlottedcountersunkscrewHexagonsocketcap六角頭螺釘雙頭螺柱頭圓柱頭螺釘盤(pán)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(lèi)PartswiththreadsusedforjoiningandfasteningarecalledscrewfastenersThemostwidelyusedcomponentsasscrewfastenersareboltsdoublescrewboltsstudscrewsnutsandwashers用螺紋聯(lián)接并起緊固作用的零件稱(chēng)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(jī)械工程專(zhuān)業(yè)英語(yǔ)機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsBoltedjointsareoneofthemostcommonelementsinconstructionandmachinedesignTheyconsistofcapscrewsorstudsthatcaptureandjoinotherpartsandaresecuredwiththematingofscrewthreadsTherearetwomaintypesofboltedjointdesignsInonetheboltistightenedtoacalculatedclamploadusuallybyapplyingameasuredtorqueloadThejointwillbedesignedsuchthattheclamploadisneverovercomebytheforcesactingonthejointandthereforethejoinedpartsseenorelativemotionTheothertypeofboltedjointdoesnothaveadesignedclamploadbutreliesontheshearstrengthoftheboltshaftThismayincludeclevislinkagesjointsthatcanmoveandjointsthatrelyonlockingmechanismlikelockwashersthreadadhesivesandlocknuts機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)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(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheclamploadalsocalledpreloadofacapscrewiscreatedwhenatorqueisappliedandisgenerallyapercentageofthecapscrewsproofstrengthCapscrewsaremanufacturedtovariousstandardsthatdefineamongotherthingstheirstrengthandclamploadTorquechartsareavailablethatidentifytherequiredtorqueforcapscrewsbasedontheirpropertyclassorgradeWhenacapscrewistighteneditisstretchedandthepartsthatarecapturedarecompressedTheresultisaspringlikeassemblyExternalforcesaredesignedtoactonthepartsthathavebeencompressedandnotonthecapscrew機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultisanonintuitivedistributionofstraininthisengineeringmodelaslongastheforcesactingonthecompressedpartsdonotexceedtheclamploadthecapscrewdonotseeanyincreasedloadThismodelisonlyvalidwhenthemembersundercompressionaremuchstifferthanthecapscrewThisisasimplifiedmodelInrealitytheboltwillseeasmallfractionoftheexternalloadpriortoitexceedingtheclamploaddependingonthecompressedpartsstiffnesswithrespecttothehardwaresstiffness機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultsofthistypeofjointdesignareGreaterpreloadsinboltedjointsreducethefatigueloadingofthehardwareForcyclicloadstheboltdoesnotseethefullamplitudeoftheloadAsaresultfatiguelifecanbeincreasedorifthematerialexhibitsanendurancelimitextendedindefinitelyAslongastheexternalloadsonajointdontexceedtheclamploadthehardwaredoesntseeanymotionandwillnotcomeloosenolockingmechanismsarerequiredInthecaseofthecompressedmemberbeinglessstiffthanthehardwaresoftcompressedgasketsforexamplethisanalogydoesntholdtrueTheloadseenbythehardwareisthepreloadplustheexternalload機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19Screwsfastenersandjoints機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsTheoryTheresultsofthistypeofjointdesignareGreaterpreloadsinboltedjointsreducethefatigueloadingofthehardwareForcyclicloadstheboltdoesnotseethefullamplitudeoftheloadAsaresultfatiguelifecanbeincreasedorifthematerialexhibitsanendurancelimitextendedindefinitelyAslongastheexternalloadsonajointdontexceedtheclamploadthehardwaredoesntseeanymotionandwillnotcomeloosenolockingmechanismsarerequiredInthecaseofthecompressedmemberbeinglessstiffthanthehardwaresoftcompressedgasketsforexamplethisanalogydoesntholdtrueTheloadseenbythehardwareisthepreloadplustheexternalload機(jī)械工程專(zhuān)業(yè)英語(yǔ)預(yù)備學(xué)識(shí)一BackgroundinationLesson19ScrewsfastenersandjointsThreadstrengthNutthreadsaredesignedtosupporttheratedclamploadoftheirrespectiveboltsIftappedthreadsareusedinsteadofanutthentheirstrengthneedstobecalculatedSteelhardwareintotappedsteelthreadsrequiresadepthof15threaddiametertosupportthefullclamploadIfanappropriatedepthofthreadsisnotavailableorthethreadsareinaweakermaterialthanthecap