專業(yè)英語全文及翻譯滾動軸承

1、Lesson 8 RollingBearingsRollingbearingscancarryradial,thrustorcombinationofthetwoloads.Accordingly,mostrollingbearingsarecategorizedinoneofthethreegroups:radialbearingsforcarryingloadsthatareprimarilyradial,thrustbearingsforsupportingloadsthatareprimarilyaxial,andangularcontactbearingsortaperedrolle

2、rbearingsforcarryingcombinedradialandaxialloads.Figure8.1ashowsacommonsingle-row,deepgrooveballbearing.Thebearingconsistsofaninnerring,anouterring,theballsandtheseparator.Toincreasethecontactareaand.hencepermitlargerloadstobecarried,theballsrunincurvilineargroovesintheringscalledraceway.Theradiusoft

3、heracewayisverylittlelargerthantheradiusoftheball.Thistypeofbearingcanstandaradialloadaswellassomethrustload.SomeothertypesofrollingbearingsareshowninFigs.8.1b,8.lcand8.1d.Figure 8.1 Some type: of rolling bearings: (a) deep groove ball bearing; (b) thrust ball bearing; (c) tapered roller thrust bear

4、ing;(d) needle roller bearing. Theconcernofamachinedesignerwithballandrollerbearingsisfivefoldasfollows:(a)lifeinrelationtoload;(b)stiffness,i.e.deflectionsunderload;(c)friction;(d)wear;(e)noise.Formoderateloadsandspeedsthecorrectselectionofastandardbearingonthebasisofloadratingwillusuallysecuresati

5、sfactoryperformance.Thedeflectionofthebearingelementswillbecomeimportantwhereloadsarehigh,althoughthisisusuallyoflessmagnitudethanthatoftheshaftsorothercomponentsassociatedwiththebearing.Wherespeedsarehighspecialcoolingarrangementsbecomenecessarywhichmayincreasefrictionaldrag.Wearisprimarilyassociat

6、edwiththeintroductionofcontaminants,andsealingarrangementsmustbechosenwithregardtothehostilityoftheenvironment.Becausethehighqualityandlowpriceofballandrollerbearingsdependsonquantityproduction,thetaskofthemachinedesignerbecomesoneofselectionratherthandesign.Rollingbearingsaregenerallymadewithsteelw

7、hichisthrough-hardenedtoabout900HV.Owingtothehighstressesinvolved,apredominantformoffailureshouldbemetalfatigue,andagooddealofworkiscurrentlyinprogressintendedtoimprovethereliabilityofthistypeofbearing.Designcanbebasedonacceptedvaluesoflifeanditisgeneralpracticeinthebearingindustrytodefinetheloadcap

8、acityofthebearingasthatvaluebelowwhich90percentofabatchwillexceedalifeofonemillionrevolutions.Notwithstandingthefactthatresponsibilityforthebasicdesignofballandrollerbearingsrestswiththebearingmanufacturer,themachinedesignermustformacorrectappreciationofthedutytobeperformedbythebearingandbeconcerned

9、notonlywithbearingselectionbutwiththeconditionsforcorrectinstallation.Thefitofthebearingringsontotheshaftsorontothehousingsisofcriticalimportancebecauseoftheircombinedeffectontheinternalclearanceofthebearingaswellaspreservingthedesireddegreeofinterferencefit.Inadequateinterferencecaninduceserioustro

10、ublefromfrettingcorrosion.Theinnerringisfrequentlylocatedaxiallybyabuttingagainstashoulder.Afilletradiusatthispointisessentialfortheavoidanceofstressconcentrationandtheinnerringisprovidedwithacornerradiusorchamfertoallowspaceforthis.Wherelifeisnotthedeterminingfactorindesign,itisusualtodeterminemaxi

11、mumloadingbytheamounttowhichabearingwilldeflectunderload.Thustheconceptofstaticload-carryingcapacityisunderstoodtomeantheloadthatcanbeappliedtoabearing,whichiseitherstationaryorsubjecttoslightswivelingmotions,withoutimpairingitsrunningqualitiesforsubsequentrotationalmotion.Thishasbeendeterminedbypra

12、cticalexperienceastheloadwhichwhenappliedtoabearingresultsinatotaldeformationoftherollingelementandracewayatanypointofcontactnotexceeding0.01percentoftherolling-elementdiameter.Thiswouldcorrespondtoapermanentdeformationof0.0025mmforaball25mmindiameter.Thesuccessfulfunctioningofmanybearingsdependsupo

13、nprovidingthemwithadequateprotectionagainsttheirenvironment,andinsomecircumstancestheenvironmentmustbeprotectedfromlubricantsorproductsofdeteriorationofthebearingsurfaces.Achievementofthecorrectfunctioningofsealsisanessentialpartofbearingdesign.Moreover,sealswhichareappliedtomovingpartsforanypurpose

14、areofinteresttotribologistsbecausetheyarecomponentsofbearingsystemsandcanonlybedesignedsatisfactorilyonthebasisoftheappropriatebearingtheory.Notwithstandingtheirimportance,theamountofresearcheffortthathasbeendevotedtotheunderstandingofthebehaviorofsealshasbeensmallwhencomparedwiththatdevotedtoothera

15、spectsofbearingtechnology.WordsandExpressionsradialbearing向心軸承(主要用于承受徑向載荷的滾動軸承)thrustbearing推力軸承(主要用于承受軸向載荷的滾動軸承)angularcontactbearing角接觸軸承taperedrollerbearing圓錐滾子軸承deepgrooveballbearing深溝球軸承thrustballbearing推力球軸承(滾動體是球的推力滾動軸承)taperedrollerthrustbearing推力圓錐滾子軸承(滾動體是圓錐滾子的推力滾動軸承)needlerollerbearing滾針軸

16、承(滾動體是滾針的向心滾動軸承)fivefolda.;ad.五倍(的)，五重的stiffnessstifnisn.剛性，剛度，穩(wěn)定性deflectionn.偏差，偏移，彎曲，撓度frictionala.摩擦的，由摩擦產生的dragv.拖，牽引，摩擦，拖著，阻礙;n，阻力，摩擦力，阻尼wearv.n.磨損，磨蝕，消耗，耗損contaminantn.沾染，雜質，污染物質，污染劑sealingn.密封，封接hostilityn.敵視，敵意，敵對through-hardenv.整體淬火HV=Vickershardness維氏硬度 notwithstandingprep.;ad.;conj.雖然，盡管(

17、還是)clearancen.間隙，裕度，空隙，余地，間距interferencen.干涉，干擾，妨礙，過盈，相互影響fretv.侵蝕，腐蝕，磨損，損壞frettingn.松散，微振磨損abutv.鄰接，毗連，倚著，支撐;n.端，盡頭，支架chamfern.;二在開槽，倒棱，倒角，圓角swiveln.旋轉軸承，轉體;v.旋轉，用活節(jié)連接racewayn.軸承座圈，滾道lubricantn.潤滑劑，潤滑材料;a.潤滑的deteriorationn.變質，退化，惡化，變壞tribologyn.摩擦學Notes1.through-hardened意為“整體淬火的，。2.frettingcorrosio

18、n意為“微動腐蝕(即由腐蝕和兩固體接觸面有微小振幅的振動而引起的磨損之聯合作用所產生的材料破壞)”。3.staticload-carryingcapacity意為“靜態(tài)承載能力”。第8課 滾動軸承滾動軸承可以承受徑向載荷，軸向載荷或者同時承受這兩種載荷。因而，大部分滾動軸承可以被劃分為三種類型:向心軸承，主要承受徑向載荷；推理軸承，主要承受軸向載荷；角接觸軸承貨圓錐滾子軸承，能同時承受徑向和軸向載荷。一個普通的蛋類深溝球軸承的結構如圖8.1a所示，它由內圈、外圈、球和保持架四部分組成。為了增加接觸面積以承受更大的載荷，球在內、外圈上的被稱為滾到的弧形溝內滾動。滾道的圓弧半徑略大于滾動球的半徑。

19、這種軸承能夠承受徑向載荷，也可以承受一定的軸向載荷。其他幾種類型的滾動軸承如圖8.1b，圖8.1c和圖8.1d所示。對于球軸承和滾子軸承，一個機器設計人員應該考慮下面的五個方面：（a）壽命與載荷的關系；（b）剛度，也就是在載荷作用下的變形；（c）摩擦；（d）磨損；（e）噪音。對于中等載荷和轉速，根據額定負載選擇一個標準軸承，通常都可以保證其具有令人滿意的工作性能。當載荷較大時，軸承零件的變形，盡管它通常小于軸和其他與軸承一起工作的零部件的變形，將會變得更重要起來。在轉速高的場合需要有專門的冷卻裝置，而這可能會增大摩擦阻力。磨損主要是由于污染物的進入引起的，必須選用密封裝置以防止周圍環(huán)境的不良影響。因為大批量生產這種方式決定了球軸承和滾子軸承不但質量高，而且價格低，因而機器設計人員的任務是選擇而不是設計軸承。滾動軸承通常是采用硬度約為900HV，整體淬火的鋼來制造的。滾動軸承由于在工作中會產生高的應力，其主要失效形式是金屬疲勞。目前人們正在進行大量的研究工作以求提高這種軸承的可靠性。軸承設計是基于能夠夠被人們所接受的使命值來進行的。在軸承行業(yè)中，通常將軸承的承載能力定義為這樣的值，即所承擔的載荷小于值時，一批軸承