刘 英文习题稿(改）

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1、EXERCISESCONTENTSChapter1FundamentalPrinciplesofMachineDesignChapter2FundamentalsofTransmissionDesignChapter3FlexibleTransmissionsChapter4GearTransmissionChapter5WormGearTransmissionChapter6ShaftingChapter7BallandRollerBearingsChapter8SlidBearingsChapter9

2、BoltConnectionsandScrewChapter10SpringsChapter11MechanicalConstructionDesignChapter1FundamentalPrinciplesofMachineDesignEX.1.1Afterbeingdrawnupsnug,inFig.1-1,thenutM20isgiven120°additionalturn.Findtheforceinthepipeandthebolt.Theboltismadeofsteelandthepipe

3、ismadeofbrass.Outdiameterofthepipeis32mmandinternaldiameteris22mm,lengthofthepipeis200mm.EX.1.2Ifthethicknessofthelinkis35mm.,F=30kN.DeterminethewidthboftheoffsetlinkofFig.1-2,ifthepermissiblevalueoftheworkingstressis68MPa.Fig.1-1Fig.1-2EX.1.3Auniformbari

4、ntensionifF=5000N,F=2000N.MaterialofthebarisQ235.TakethefactorofsafetyS=1.6,basedontheyieldpoint,findthediameterofthebar.Thebarhasamachinedsurface,calculatethefactorofsafetyforinfinitelife.EX.1.4SupposethelifeNofthepartunderheavytestloadis20hr.ThelifeNund

5、ercombinedloadingwas32hr,ofwhich14hrwasatthenormalloadand18hrwasattheheavytestload.FindtheexpectedlifeNunderthenormaloperatingload.EX.1.5InFig.1-3,theleafspringisstraightandunstressedwhenthecamandshaftareremoved.Thematerialofthespringis65Mn.Notanystressco

6、ncentration.Springsurfacesareground.Ifthecamrotatescontinuously,findthesafefactorfortheleafspring.Thicknessofthespringisd=3mmandwidthb=25mm.EX.1.6AmachineelementshowninFig.1-4ismadefrom40Cr.Itissubjecttofluctuatingbendingwitha13maximumloadofF=4000N,aminim

7、umloadofF=600N.Caculatethefactorofsafetyforinfinitelifeforthepart.Fig.1-3Fig.1-4EX.1.7Acircularshaftofanelectricmotoris750mmfrombearingtobearing.Theweightoftherotoris6000N.Thematerialis45steel.Forsimplicity,wewillassumetheforceofgravityconcentratedatmidpo

8、int.Thesurfaceisground.lightshock,nostressconcentration.Calculatetheshaftdiameter.EX.1.8ThethreegearsshowninFig.1-5havetherespectivetoothnumberZ、Z、Z.AninputtorqueTisappliedtotheendAoftheshaftThetorsionalspringconsta