專業(yè)英語(yǔ)全文及翻譯滾動(dòng)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(dòng)軸承)thrustbearing推力軸承(主要用于承受軸向載荷的滾動(dòng)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(dòng)體是球的推力滾動(dòng)軸承)taperedrollerthrustbearing推力圓錐滾子軸承(滾動(dòng)體是圓錐滾子的推力滾動(dòng)軸承)needlerollerbearing滾針軸

16、承(滾動(dòng)體是滾針的向心滾動(dòng)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f(wàn)rictionala.摩擦的，由摩擦產(chǎn)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(zhì)，污染物質(zhì)，污染劑sealingn.密封，封接hostilityn.敵視，敵意，敵對(duì)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(guò)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(zhuǎn)軸承，轉(zhuǎn)體;v.旋轉(zhuǎn)，用活節(jié)連接racewayn.軸承座圈，滾道lubricantn.潤(rùn)滑劑，潤(rùn)滑材料;a.潤(rùn)滑的deteriorationn.變質(zhì)，退化，惡化，變壞tribologyn.摩擦學(xué)Notes1.through-hardened意為“整體淬火的，。2.frettingcorrosio

18、n意為“微動(dòng)腐蝕(即由腐蝕和兩固體接觸面有微小振幅的振動(dòng)而引起的磨損之聯(lián)合作用所產(chǎn)生的材料破壞)”。3.staticload-carryingcapacity意為“靜態(tài)承載能力”。第8課 滾動(dòng)軸承滾動(dòng)軸承可以承受徑向載荷，軸向載荷或者同時(shí)承受這兩種載荷。因而，大部分滾動(dòng)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(shí)承受徑向和軸向載荷。一個(gè)普通的蛋類深溝球軸承的結(jié)構(gòu)如圖8.1a所示，它由內(nèi)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(nèi)、外圈上的被稱為滾到的弧形溝內(nèi)滾動(dòng)。滾道的圓弧半徑略大于滾動(dòng)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(dòng)軸承如圖8.1b，圖8.1c和圖8.1d所示。對(duì)于球軸承和滾子軸承，一個(gè)機(jī)器設(shè)計(jì)人員應(yīng)該考慮下面的五個(gè)方面：（a）壽命與載荷的關(guān)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(duì)于中等載荷和轉(zhuǎn)速，根據(jù)額定負(fù)載選擇一個(gè)標(biāo)準(zhǔn)軸承，通常都可以保證其具有令人滿意的工作性能。當(dāng)載荷較大時(shí)，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(huì)變得更重要起來(lái)。在轉(zhuǎn)速高的場(chǎng)合需要有專門的冷卻裝置，而這可能會(huì)增大摩擦阻力。磨損主要是由于污染物的進(jìn)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?yàn)榇笈可a(chǎn)這種方式?jīng)Q定了球軸承和滾子軸承不但質(zhì)量高，而且價(jià)格低，因而機(jī)器設(shè)計(jì)人員的任務(wù)是選擇而不是設(shè)計(jì)軸承。滾動(dòng)軸承通常是采用硬度約為900HV，整體淬火的鋼來(lái)制造的。滾動(dòng)軸承由于在工作中會(huì)產(chǎn)生高的應(yīng)力，其主要失效形式是金屬疲勞。目前人們正在進(jìn)行大量的研究工作以求提高這種軸承的可靠性。軸承設(shè)計(jì)是基于能夠夠被人們所接受的使命值來(lái)進(jìn)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(dān)的載荷小于值時(shí)，一批軸承