欢迎来到天天文库
浏览记录
ID:11890684
大小:58.50 KB
页数:12页
时间:2018-07-14
《王宝帅机械类毕业设计外文文献翻译》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、沈阳工业大学工程学院毕业设计(论文)外文翻译毕业设计(论文)题目:工具盒盖注塑模具设计外文题目:Friction,LubricationofBearing译文题目:轴承的摩擦与润滑系(部):机械系专业班级:机械设计制造及其自动化0801学生姓名:王宝帅指导教师:魏晓波2010年10月15日12外文文献原文:Friction,LubricationofBearingInmanyoftheproblemthusfar,thestudenthasbeenaskedtodisregardorneglectfriction
2、.Actually,frictionispresenttosomedegreewhenevertwopartsareincontactandmoveoneachother.Thetermfrictionreferstotheresistanceoftwoormorepartstomovement.Frictionisharmfulorvaluabledependinguponwhereitoccurs.frictionisnecessaryforfasteningdevicessuchasscrewsandriv
3、etswhichdependuponfrictiontoholdthefastenerandthepartstogether.Beltdrivers,brakes,andtiresareadditionalapplicationswherefrictionisnecessary.Thefrictionofmovingpartsinamachineisharmfulbecauseitreducesthemechanicaladvantageofthedevice.Theheatproducedbyfrictioni
4、slostenergybecausenoworktakesplace.Also,greaterpowerisrequiredtoovercometheincreasedfriction.Heatisdestructiveinthatitcausesexpansion.Expansionmaycauseabearingorslidingsurfacetofittighter.Ifagreatenoughpressurebuildsupbecausemadefromlowtemperaturematerialsmay
5、melt.Therearethreetypesoffrictionwhichmustbeovercomeinmovingparts:(1)starting,(2)sliding,and(3)rolling.Startingfrictionisthefrictionbetweentwosolidsthattendtoresistmovement.Whentwopartsareatastateofrest,thesurfaceirregularitiesofbothpartstendtointerlockandfor
6、mawedgingaction.Toproducemotionintheseparts,thewedge-shapedpeaksandvalleysofthestationarysurfacesmustbemadetoslideoutandovereachother.Therougherthetwosurfaces,thegreaterisstartingfrictionresultingfromtheirmovement.Sincethereisusuallynofixedpatternbetweenthepe
7、aksandvalleysoftwomatingparts,theirregularitiesdonotinterlockoncethepartsareinmotionbutslideovereachother.Thefrictionofthetwosurfacesisknownasslidingfriction.Asshowninfigure,startingfrictionisalwaysgreaterthanslidingfriction.Rollingfrictionoccurswhenrollerdev
8、cesaresubjectedtotremendousstresswhichcausethepartstochangeshapeordeform.Undertheseconditions,thematerialinfrontofarollertendstopileupandforcestheobjecttorollslightlyuphill.Thischangingof
此文档下载收益归作者所有