机械设计及其自动化毕业设计外文翻译中英文轴承的摩擦与润滑

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1、机械设计及其自动化毕业设计外文翻译中英文轴承的摩擦与润滑广西大学毕业设计（论文）外文翻译毕业设计（论文）题目：夕卜文题目:Friction,LubricationofBearing译文题目：轴承的摩擦与润滑系别：机械工程系专业:机械工程制造及其自动化班级：学号：姓名：指导教师：外文文献原文：Friction,LubricationofBearingTnmanyoftheproblemthusfar,thestudenthasbeenaskedtodisregardorneglectfrictionActually,fri

2、ctionispresenttosomedegreewhenevertwopartsareincontactandmoveoneachother.Thetermfrictionreferstothercsistanccoftwoormorepartstomovcment.Frictionisharmfu1orvaluabledependinguponwhereitoccurs.frictionisnecessaryforfasteningdevicessuchasscrewsandrivetswhichdependupo

3、nfrictiontoholdthefastenerandthepartstogether.Beltdrivers,brakes,andtiresareadditionalapplicationswherefrictionisnecessary.Thefrictionofmovingpartsinamachineisharmfulbecauseitreducesthemechcinicaladvantageofthedevice-Theheatproducedbyfrictionislostenergybecauseno

4、worktakesplace.Also,greaterpowerisrequiredtoovercometheincreasedfriction.Heatisdestructiveinthatitcausesexpansion.Expansionmaycauseabearingorslidingsurfacetofittighter.Ifagreatenoughpressurebuildsupbecausemadefromlowtemperaturematerialsmaymelt.Therearethreetypeso

5、ffrictionwhichmustbeovercomeinmovingparts:lstarting,2sliding，and3rolling.Startingfrictionisthefrictionbetweentwosolidsthattendtoresistmovement.Whentwopartsareatastateofrest,thesurfaceirregularitiesofbothpartstendtointcrlockandformawedgingaction.Toproducemotionint

6、hoseparts，thewedge-shapedpeaksandvalleysofthestationarysurfacesmustbemadetoslideoutandovereachother.Therougherthetwosurfaces,thegreaterisstartingfrictionresultingfromtheirmovementSincethereisusuallynofixedpa.tternbetweenthepeaksandvalleysoftwomatingparts,theirreg

7、ulariticsdonotintorlockoncethepartsareinmotionbutslideovereachother.Thefrictionofthetwosurfacesisknownasslidingfriction.Asshowninfigure,startingfrictionisalwaysgreatcTthanslidingfrictionRollingfrictionoccurswhenrollerdevcesaresubjectedtotremendousstresswhichcause

8、thepartstochangesheipeordeform.Undertheseconditions,thematerialinfrontofarollertendstopileupandforcestheobjecttorollslightlyuphill.Thischangingofshape,knownasd