外文翻譯--影響機(jī)械設(shè)計(jì)暫停動(dòng)態(tài)加載過程.doc_第1頁
外文翻譯--影響機(jī)械設(shè)計(jì)暫停動(dòng)態(tài)加載過程.doc_第2頁
外文翻譯--影響機(jī)械設(shè)計(jì)暫停動(dòng)態(tài)加載過程.doc_第3頁
外文翻譯--影響機(jī)械設(shè)計(jì)暫停動(dòng)態(tài)加載過程.doc_第4頁
外文翻譯--影響機(jī)械設(shè)計(jì)暫停動(dòng)態(tài)加載過程.doc_第5頁
已閱讀5頁,還剩10頁未讀, 繼續(xù)免費(fèi)閱讀

付費(fèi)下載

下載本文檔

版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)

文檔簡(jiǎn)介

1M.SukD.GillisEffectofmechanicaldesignofthesuspensionondynamicloadingprocessReceived:2July2003/Accepted:24February2004/Publishedonline:3August2005_Springer-Verlag2005Abstract:Indesigningaload/unloadsystemutilizedinharddiskdrives,necessarycareneedstobetakentoensurethatthesliderdoesnotdamagethedisksurfaceduringloadingandunloadingprocesses.However,asmalldeviationinthedesignpointofthepreloadbetweentheload-domeandflexurecanleadtoundesirableloadingprocessesresultinginanadversenumberofslider/diskcontacts.Inthisstudy,weshowthatifthepreloadbetweentheload-domeandflexureistoolow,theslidercanoscillatecausingthecornersoftheslidertocontactthediskmultipletimeseventhoughthesliderisafewmicronsawayfromthedisk.Inaddition,theslidercanbesuckeddowntowardsthediskresultinginacompleteseparationoftheload-domefromtheflexureassemblyleadingtouncontrolledloadingconditions.Thisseparationoccurswhilethesuspensionisstillontheramp,andthusnopreloadisexertedonthesliderimmediatelyfollowingtheseparation.Consequently,thesliderfliesataflyingheighthigherthanthedesignpointuntilthegapbetweentheload-domeandflexurecloses.Hence,thesuspensionmustbecarefullydesignedtosuppressslideroscillationandtoensurethattheloaddomedoesnotseparateduringtheloadingprocess.1IntroductionOneoftherequirementsindesigningaload/unloadsystemutilizedinharddiskdrivesisensuringthatthesliderdoesnotdamagethedisksurfaceduringloadingandunloadingprocesses.Sinceitisdifficulttoavoidslider/diskcontactsinentirety,however,thesystemisdesignedtominimizethenumberofslider/diskcontacteventsandtolessentheconsequenceswhencontactsdooccur.Thelikelihoodofslider/diskcontactsdependsontheloadingspeed,diskspeed,staticattitudeoftheslider,air-bearingroughness,slidergeometry,etc.Forexample,sliderswithalargeradiusofcurvatureatitscornerscaneliminatediskdamagebyreducingthecontactstressbetweentheslideranddisksurface(SukandGillis1998).Manyrecentstudieshaveconsideredtheeffectofsuspension,limiter,andair-bearingdesignsontherobustnessoftheloadingandunloadingprocesses(B2ogyandZeng2000;Huaetal.2001;LiuandZhu2001;ZengandBogy2000).However,mostofthesestudieshaveprimarilyfocusedontheunloadingprocesssincethispartofthesequenceusuallyrevealsinterestingdynamicprocessesduetotheeffectsofnegativepressureairbearingdesigns.Thenegativepressureregionoftheairbearingresiststheunloadingactionresultinginstorageofpotentialenergyintheflexureandsuspensionassembly.Whenthesliderisfinallypulledawayfromthediskandthepotentialenergyisreleased,theslidercanoscillateviolently(Fig.1).Ontheotherhand,forareasonablywell-designedsystem,theloadingprocessdoesnotexhibitsuchabehavior.Hence,mosthaveprimarilyinvestigatedtheunloadingprocessgivingonlacursoryattentiontothemorecriticalloadingprocess.Mostdesignersofload/unloadsystemswillfindthattheloadingprocesscanbemoretroublesomecomparedtotheunloadingprocess.Besidespotentiallycausingdamagetothedisk,otherproblemscanbeencounteredduringtheloadingprocess.Forexample,insomeinstances,theslidermayneverloadtothedesignedflyingheight,butrather,loadatflyingheightsontheorderof1lm(Suketal.2004).Inthispaper,weshowhowasmalldeviationinthemechanicaldesignoftheflexure/suspensionassemblycanincreasetheprobabilityofslider/diskcontactsthatcanleadtoasignificantnumberofdiskcontactsinonesingleloadcycle.Specifically,weshowthatasuspensionsystemwithlowpreloadbetweentheflexureandloaddomecanleadtoloadingoftheslideratanuncontrolledstaticattitudeandvelocity.Theproblemsassociatedwiththisparticularaspectofdesigncanbeeasilyidentifiedbymeasuringthefull-bodycapacitanceduringtheloadingprocess.2DescriptionofexperimentThesliderloadingdynamicswasinvestigatedusingalaser-Dopplervibrometer(LDV),62kHzframeratehigh-speedcamera,andfull-bodycapacitance.Theexperimentalsetupconsistsofastandardload/unloadtester.Thecapacitancemetermeasuresthefull-bodycapacitancebetweentheslideranddiskwhilethesliderisloadingontothedisk,similartotheoneusedin(Suketal.2004).Thesliderwasloadedontoan3dunloadedfromthediskusingamovingrampwhilekeepingtheslider/suspensionassemblyfixedovertheODregionofthedisk.TheverticalmotionofthetrailingedgeofthesliderwasmeasuredusinganLDV.Alltestswerecarriedoutusingan84mmglassdiskandanegativepressurebobsledtypesliderwiththediskrotatingat10krpm.Thepitch-staticattitude(PSA)oftheslidersusedintheexperimentwasbetween1and2_.Toshowtheeffectoflackofpreloadbetweentheflexureandload-dome,wechosetwosuspensionassembliesthatareessentiallyidenticalwiththeexceptionofthepreload.Sincethedifferenceinthemagnitudeofthepreloadisdifficulttomeasure,onlytheexistenceofsubstantialdifferenceisverified.Todothis,wemounttheheadsuspensionassemblywithnormalpreload(NPHSA)ontotheramp.Asmallweight,thatissufficienttocauseload-domeseparationfromtheflexure,isthenattachedtotheflexure.TheamountofseparationismeasuredwithaproperlypositionedCCDcamera.Similarmeasurementismadeforaheadsuspensionassemblywithlowpreload(LP-HSA).Figures2and3showopticalimagesoftheload-domeandflexuretakenunderthesameconditionsforbothNP-HSAandLPHSA,respectively.Agreaterload-domeseparationfromtheflexureisobservedforLP-HSAthantheNP-HSA,confirmingthatLP-HSAhaslowerpreloadthanNPHSA.3ResultsanddiscussionnegativepressureslidersT4hesliderloadsontothediskandthenfollowstherunoutofthediskasexpected.ThebottomplotinFig.3isthecorrespondingfull-bodycapacitancemeasurement,whichshowsasinglejumpinthecapacitanceatthemomentthesliderloadsontothedisk.AsimilarmeasurementforLP-HSAisshowninFig.5.Inthiscase,theslideroscillatesbeforeloadingontothediskunlikethecasewithahigherpreloadbetweentheload-domeandflexure.Furthermore,theslidersverticalloadingvelocitysuddenlyincreaseswhenthesliderisabout50lmawayfromthedisk.Associatedwiththissuddenincreaseinthevelocity,thecapacitancemeasurementrevealsmultiplesharptransitions.Followingthetransitions,thecapacitancedoesnotreachthemaximumvalueforanother1msorso.Theseobservationsindicateaproblem,butitisdifficulttoascertaintheprecisedynamicsduetothelowmeasurementbandwidth.Higherresolutionmeasurementrevealsthattheslidercontactsthediskmultipletimes(Fig.6)notethatthisexactbehaviordoesnotoccurforeverysuspensionassembly,butvariesfromonesuspensiontoanother.Figure6showssimultaneousmeasurementoffull-bodycapacitanceandLDVduringloadingforLP-HASimmediatelybeforefullyloadingontothedisksurface.Capacitancemeasurementshowssomeoscillationabout2msbeforeastep-likejumpisobserved.Notethattheaverageheightofthesliderduringtheseoscillationsisontheorderofafewmicrons.Atthisheight,thesuspensionpreload(notthepreloadbetweentheflexureandload-dome)isstillsupportedbytheramp.TheLDVmeasurementshowsthattheslideractuallycontactsthediskandbounceson-and-offthediskoscillatingatthesamefrequencyasthatofthemeasurementmadewiththecapacitancemet

溫馨提示

  • 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
  • 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
  • 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
  • 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
  • 5. 人人文庫(kù)網(wǎng)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
  • 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
  • 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。

最新文檔

評(píng)論

0/150

提交評(píng)論