資源描述：
《機械外文翻譯中英文》由會員上傳分享，免費在線閱讀，更多相關內(nèi)容在行業(yè)資料-天天文庫。
1、附錄附錄1英文原文RollingContactBearingsTheconcernofamachinedesignerwithballandrollerbearingsisfivefoldasfollows:(a)lifeinrelationtoload;(b)stiffness,ie.deflectionsunderload;(c)friction;(d)wear;(e)noise.Formoderateloadsandspeedsthecorrectselectionofastandardbearingonthebasisofaloadratingwillbecomeimporta
2、ntwhereloadsarehigh,althoughthisisusuallyoflessmagnitudethanthatoftheshaftsorothercomponentsassociatedwiththebearing.Wherespeedsarehighspecialcoolingarrangementsbecomenecessarywhichmayincreasefricitionaldrag.Wearisprimarilyassociatedwiththeintroductionofcontaminants,andsealingarrangementsmustbec
3、hosenwithregardtothehostilityoftheenvironment.Becausethehighqualityandlowpriceofballandrollerbearingdependsonquantityproduction,thetaskofthemachinedesignerbecomesoneofselectionratherthandesign.Rolling-contactbearingsaregenerallymadewithsteelwhichisthrough-hardenedtoabout900HV,althoughinmanymecha
4、nismsspecialracesarenotprovidedandtheinteractingsurfacesarehardenedtoabout600HV.Itisnotsurprisingthat,owingtothehighstressesinvolved,apredominantformoffailureshouldbemetalfatigue,andagooddealofworkisbasedonacceptvaluesoflifeanditisgeneralpracticeinbearingindustrytodefinetheloadcapacityofthebeari
5、ngasthatvaluebelowwhich90percentofabatchwillexceedlifeofonemillionrevolutions.Notwithstandingthefactthatresponsibilityforbasicdesignofballandrollerbearingsrestswiththebearingmanufacturer,themachinedesignermustformacorrectappreciationofthedutytobeperformedbythebearingandbeconcernednotonlywithbear
6、ingselectionbutwiththeconditionsforcorrectinstallation.Thefitofthebearingracesontotheshaftorontothehousingsisofcriticalimportancebecauseoftheircombinedeffectontheinternalclearanceofthebearingaswellaspreservingthedesireddegreeofinterferencefit.Inadequateinterferencecaninduceserioustroublefromfret
7、tingcorrosion.Theinnerraceisfrequentlylocatedaxiallybyagainstashoulder.Aradiusatthispointisessentialfortheavoidanceofstressconcentrationandballracesareprovidedwitharadiusorchamfertofollowspaceforthis.Wherelifeisnotthedetermi
