机械制造专业外文翻译--滚动轴承1.pdfVIP

外文原文：

RollingContactBearings

Theconcernofamachinedesignerwithballandrollerbearingsisfivefoldas

follows:(a)lifeinrelationtoload;(b)stiffness,i.e.deflectionsunderload;(c)friction;

(d)wear;(e)noise.Formoderateloadsandspeedsthecorrectselectionofastandard

bearingonthebasisofloadratingwillbecomeimportantwhereloadsarehigh,

althoughthisisusuallyoflessmagnitudethanthatoftheshaftsorothercomponents

associatedwiththebearing.Wherespeedsarehighspecialcoolingarrangements

becomenecessarywhichmayincreasefrictionaldrag.Wearisprimarilyassociated

withtheintroductionofcontaminants,andsealingarrangementsmustbechosenwith

regardtothehostilityoftheenvironment.

Becausethehighqualityandlowpriceofballandrollerbearingsdependson

quantityproduction,thetaskofthemachinedesignerbecomesoneofselectionrather

thandesign.Rolling-contactbearingsaregenerallymadewithsteelwhichis

through-hardenedtoabout900HV,althoughinmanymechanismsspecialracesare

notprovidedandtheinteractingsurfacesarehardenedtoabout600HV.Itisnot

surprisingthat,owingtothehighstressesinvolved,apredominantformoffailure

shouldbemetalfatigue,andagooddealofworkisbasedonacceptedvaluesoflife

anditisgeneralpracticeinthebearingindustrytodefinetheloadcapacityofthe

bearingasthatvaluebelowwhich90percentofabatchwillexceedalifeofone

millionrevolutions.

Notwithstandingthefactthatresponsibilityforthebasicdesignofballandroller

bearingsrestswiththebearingmanufacturer,themachinedesignermustforma

correctappreciationofthedutytobeperformedbythebearingandbeconcernednot

onlywithbear