ROLLING CUTTER BITS牙輪鉆頭英文簡介_第1頁
ROLLING CUTTER BITS牙輪鉆頭英文簡介_第2頁
ROLLING CUTTER BITS牙輪鉆頭英文簡介_第3頁
ROLLING CUTTER BITS牙輪鉆頭英文簡介_第4頁
ROLLING CUTTER BITS牙輪鉆頭英文簡介_第5頁
已閱讀5頁,還剩18頁未讀, 繼續(xù)免費(fèi)閱讀

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),請進(jìn)行舉報(bào)或認(rèn)領(lǐng)

文檔簡介

ROLLINGCUTTERBITSConesrotateabouttheiraxisasthebitisrotatedaboutitsownaxis.ByfarthemostcommonbittypecurrentlyusedSuitedforawidevarietyofformationcharacteristicsAvailablewithalargevarietyofToothdesign

BearingtypesThebiggestlimitationindesigningRCBistat:

Thebitmustfitinsidetheborehole.ThedesignerisrequiredtomakemaximumuseofaverylimitedspaceThesizeofeverycriticalpartcanbeincreasedonlyattheexpenseofanotherpart.ThedrillingactionofaRCBdependstosomeextentontheoffsetofthecones.Theconesaremovedsothattheiraxesdonotintersectatacommonpoint.Offsetangle:Changesfrom0o(hard)to

4o(soft)formations.Causestheconescrapetheholebottomlikeadragbit.TendstoincreasetheROPForsoftformationsLong,WidelySpaced,Steelteeth.Longteetheasilypenetrateandplowingactionoftheoffsetconeremovesthematerial.Italsopromotesfastertoothwearinabrasiveformations.Thewidespacingoftheteethontheconepromotescleaning.TheshapeofbitteethalsohasabigeffectonthedrillingactionofaRCB.ForHarderRocksThetoothlengthandconeoffsetmustbereducedtopreventtoothbreakage.Thedrillingactionofabitwithzeroconeoffsetisessentiallyacrushingaction.Thesmallerteethalsoallowmoreroomfortheconstructionofstrongerbearings.Milledtoothcuttersaremanufacturedbymillingtheteethoutofasteelcone.Milledtoothbitsdesignedforsoftformationsusuallyarefacedwithawearresistantmaterial,suchastungstencarbide,ononesideofthetooth.Hardfacingononesideallowsmorerapidwearononesideofthetooththantheotherandthetoothstaysrelativelysharp.Themetallurgyrequirementsofthebitteethalsodependsontheformationcharacteristics.Themilledtoothbitsdesignedtodrillharderformationsareusuallycasehardenedbyspecialprocessingandheattreatingthecutterduringmanufacturing.Thiscase-hardenedsteelshouldwearbychippingandtendtokeepthebittoothsharp.Tungstencarbideinsertcuttersaremanufacturedbypressingatungstencarbidecylinderintoaccuratelymachinedholesinthecone.Theinnerrowsofteetharepositionedondifferentconessothattheyintermesh.Theintermeshingallowsmoreroomforastrongerbitdesign.Providesaself-cleaningactionasthebitturns.Allowsmaximumcoverageoftheholebottom.70%Thebottomholecoverageofmostbitsisabout70%.Theouterrowofbitteeth,heelteeth,hasthehardestjob.Duetothecirculargeometry,morerockmustberemovedfromtheoutermostannularringoftheholebottom.Thisrockismoredifficulttoremovebecauseittendstoremainattachedtotheboreholewall.Theheelteethmaywearexcessively,causingthebittodrillanout-of-gaugehole.Thiscausesagrossmisalignmentoftheloadonthebearingsandprematurebitfailure.Prematurefailureofthenextbitisalsolikelyiftheholeremainsundersized.ThecommonbearingassembliesusedforRCBare:StandardRollerBearing,Gas-CooledBearingdesignfordrillingwithAirorN/G,SealedRollerBearing,Journalbearing.ThestandardrollerbearingsThemostinexpensiveoneAllbearingsarelubricatedbythedrillingfluidThestandardrollerbearingsconsistsof:Aroller-typeouterbearing,Aball-typeintermediatebearing,Afriction-typenosebearing.Theroller-typeouterbearingThemostheavilyloadedmember.Usuallytendstowearoutfirst.Wearonthebottomsidewheretheweightappliedtothebitistransmittedfromthepintothecone.Theintermediateballbearings

Carryprimarilyaxialloadsonthecones.Alsoservetoholdtheconeinplaceonthebit.ThenosebearingsDesignedtocarryaportionoftheaxialloadsaftertheballbearingsbegintowear.Thenosebearingisafriction-typebearinginmostbitsizes,butinthelargerbitsizesanotherrollerbearingisused.Gas-CooledBearing

designFordrillingwithAir/N/GAmodifiedbitisavailablewithpassagewayspermittingaportionofthegastoflowthroughthebearingassemblyThesealedbearingassemblyTheintermediate-costbearingassemblyThebearingsaremaintainedinagreaseenvironmentbygreasesealsandareservoir.Acompensatorplugallowsthegreasepressuremaintainedequaltothehydrostaticfluidpressureatthebottomofthehole.Thegreasesealsrequiresomespaceand,thus,areductioninbearingcapacity.Theeliminationofabrasivematerialfrombearingsusuallymorethancompensatesforthisdisadvantage.Asthebitwears,thegreasesealseventuallyfailandthedrillingfluidcanenterthebearingsandacceleratethebearingwear.Thejournalbearingassembly

ThemostadvancedbearingtypeTherollerbearingsareeliminatedandtheconerotatesincontactwiththejournalbearingpin.Byeliminatingoneoftherollers,additionalspacebecomesavailableforstrengtheningtheremainingcomponents.HastheadvantageofgreatlyincreasingthecontactareathroughwhichtheWOBtransmittedonthecone.Journalbearingbitsrequireeffectivegreaseseals,specialmetallurgy,ande

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. 人人文庫網(wǎng)僅提供信息存儲(chǔ)空間,僅對用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對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自己和他人造成任何形式的傷害或損失。

評論

0/150

提交評論