機(jī)械工程專業(yè)英語ppt

Lesson

8RollingBearings2/1/2023TerminologyTexttour

《機(jī)械工程專業(yè)英語教程》1RollingBearings滾動(dòng)軸承TerminologyBearingAdevicethatsupports,guides,andreducesthefrictionofmotionbetweenfixedandmovingmachineparts.軸承：在機(jī)器的固定和運(yùn)動(dòng)部件之間起支撐、引導(dǎo)和減少運(yùn)動(dòng)摩擦作用的裝置.2/1/2023《機(jī)械工程專業(yè)英語教程》2TerminologyFretTowearaway,erode磨損或腐蝕LubricantAsubstance,suchasgreaseoroil,thatreducesfrictionwhenappliedasasurfacecoatingtomovingparts.潤滑劑：一種脂或油的物質(zhì)，被用在運(yùn)動(dòng)部分表面時(shí)可減少摩擦2/1/2023《機(jī)械工程專業(yè)英語教程》3AlloyAhomogeneousmixtureorsolidsolutionoftwoormoremetals,theatomsofonereplacingoroccupyinginterstitialpositionsbetweentheatomsoftheother合金：兩種或更多種金屬的均勻混合物或固溶體，一種金屬的原子代替或占據(jù)了另一種金屬晶格中節(jié)點(diǎn)間隙。Brassisanalloyofcopperandzinc.黃銅是銅和鋅的合金Modulus模量Aquantitythatexpressesthedegreetowhichasubstancepossessesaproperty,suchaselasticity模量：一種參數(shù)，表示一種物質(zhì)具有的一個(gè)特性之程度，如彈性。2/1/2023《機(jī)械工程專業(yè)英語教程》4Texttour

Figure8.1ashowsacommonsingle-row,deepgrooveballbearing.Thebearingconsistsofaninnerring,anouterring,theballsandtheseparator.Toincreasethecontactareaandhencepermitlargerloadstobecarried,theballsrunincurvilineargroovesintheringscalledraceway.一個(gè)普通的單列深溝球軸承的結(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)、外圈上的被稱為滾道的弧形溝內(nèi)滾動(dòng)?！稒C(jī)械工程專業(yè)英語教程》52/1/2023SomeothertypesofrollingbearingsareshowninFigs.8.1b,8.1cand8.1d.(b)thrustballbearing;(c)taperedrollerthrustbearing;(d)needlerollerbearing

(b)推力球軸承,(c)推力圓錐滾子軸承,(d)滾針軸承

《機(jī)械工程專業(yè)英語教程》62/1/2023Theconcernofamachinedesignerwithballandrollerbearingsisfivefoldasfollows:(a)lifeinrelationtoload;(b)stiffness,i.e.deflectionsunderload;(c)friction;(d)wear;(e)noise.Formoderateloadsandspeedsthecorrectselectionofastandardbearingonthebasisofloadratingwillusuallysecuresatisfactoryperformance.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)荷選擇一個(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。2/1/2023《機(jī)械工程專業(yè)英語教程》7Owingtothehighstressesinvolved,apredominantformoffailureshouldbemetalfatigue,andagooddealofworkiscurrentlyinprogressintendedtoimprovethereliabilityofthistypeofbearing.Designcanbebasedonacceptedvaluesoflifeanditisgeneralpracticeinthebearingindustrytodefinetheloadcapacityofthebearingasthatvaluebelowwhich90percentofabatchwillexceedalifeofonemillionrevolutions.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)可以基于能夠被人們所接受的壽命值來進(jìn)行。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)的載荷小于這個(gè)值時(shí)，一批軸承中將會(huì)有90%的軸承具有超過一百萬轉(zhuǎn)的壽命。2/1/2023《機(jī)械工程專業(yè)英語教程》8Theinnerringisfrequentlylocatedaxiallybyabuttingagainstashoulder.Afilletradiusatthispointisessentialfortheavoidanceofstressconcentrationandtheinnerringisprovidedwithacornerradiusorchamfertoallowspaceforthis.

內(nèi)圈通常是通過緊靠在軸肩上進(jìn)行軸向定位的。軸肩根部過渡圓角半徑對(duì)避免產(chǎn)生應(yīng)力集中是必要的。軸承內(nèi)圈上的圓角半徑或者倒角提供了容納軸肩過渡圓角半徑的空間。

2/1/2023《機(jī)械工程專業(yè)英語教程》9Shoulderfilletandbearinginnerring

Thesuccessfulfunctioningofmanybearingsdependsuponprovidingthemwithadequateprotectionagainsttheirenvironment,andinsomecircumstancestheenvironmentmustbeprotectedfromlubricantsorproductsofdeteriorationofthebearingsurfaces.Achievementofthecorrectfunctio