外文翻译---轴、联轴器和滚动轴承

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1、设计巴巴工作室www.88doc88.com附录二外文原文和翻译shafts、couplingsandrollingcontactbearingskeywords:shafts、couplings、bearingsVirtuallyallmachinescontainshafts.Themostcommonshapeforshaftsiscircularandthecrosssectioncanbeeithersolidorhollow(hollowshaftscanresultinweightsavings).Rectangularshaftsaresometimesused,asi

2、nscrewdriverblades,socketwrenchesandcontrolknobstems.Ashaftmusthaveadequatetorsionalstrengthtotransmittorqueandnotbeoverstressed.Italsobetorsionallystiffenoughsothatonemountedcomponentdoesnotdeviateexcessivelyfromitsoriginalangularpositionrelativetoasecondcomponentmountedonthesameshaft.Generally

3、speaking,theangleoftwistshouldnotexceedonedegreeinashaftlengthequalto20diameters.Shaftsaremountedinbearingsandtransmintpowerthroughsuchdevicesasgears,pullerys,camsandclutches.Thesedevicesintroduceforceswhichattempttobendtheshaft;hence,theshaftmustberigidenoughtopreventoverloadingofthesupportingb

4、earings.Ingeneral,thebendingdeflectionofashaftshouldnotexceed0.01in.perftoflengthbetweenbearingsupports.Inaddition,theshaftmustbeabletosustainacombinationofbendingandtorsionalloads.Thusanequivalentloadmustbeconsidered设计巴巴工作室www.88doc88.comwhichtakesintoaccountbothtorsionandbending.Also,theallowa

5、blestressmustcontainafactorofsafetywhichincludesfatigue,sincetorsionalandbendingstressreversalsoccur.Fordiameterslessthan3in.,theusualshaftmaterialiscold-rolledateelcontainingabout0.4percentcarbon.Shaftsareeithercold-rolledorforgedinsizesfrom3in.to5in.,shaftsareforgedandmachinedtosize.Pleasticsh

6、aftsarewidelyusedforlightloadapplications.Oneadvantageofusingplasticissafetyinelectricalapplications,sinceplasticisapoorconductorofelectricity.Componentssuchasgearsandpulleysaremountedonshaftsbymeansofkey.Thedesignofthekeyandthecorrespondingkeywayintheshaftmustbeprperlyevaluated.Forexample,stres

7、sconcentrationsoccurinshaftsduetokeyways,andthematerialremovedtoformthekeywayfurtherweakenstheshaft.Ifshaftsarerunatcirticalspeeds,severevibrationscanoccurwhichcanseriouslydamageamachine.Itisimportanttoknowthemagnitudeofthes