矿井架空乘人装置设总体计

摘要本文主要是设计一款架空乘人装置。在进行设计时首先分析了现有架空乘人装置的工作原理及系统组成，以及目前架空乘人装置的存在主要问题及未来的发展趋势。然后根据给定的条件设计由电动机，行星减速器，锥齿轮减速器，托压轮，摩擦盘以及尾轮等组成的常规型架空乘人装置。设计中主要对常规型架空乘人装置的行星减速器，锥齿轮减速器以及钢丝绳与滑轮进行了选型与设计。同时，对于制动器，联轴器以及架空乘人装置的日常使用及维护进行了涉及和说明。为了使设计更加可靠，关键词：架空乘人装置;行星减速器;钢丝绳ABSTRACTThispaperistodesignanaerialpassengerdevice.Whenmakingdesign,firstofall,analysestheexistingaerialpassengerdevice'sworkingprincipleandsystemcomposition,andanalysesthemainproblemsandthefuturetrendofdevelopmentoftheaerialpassengerdevice.Thendesignthemotor,planetarygearreducer,bevelgearreducer,pressurewheel,frictionplateandthetailwheeldeviceandsoonaccordingtothegivenconditions.Theplanetarygearreducer,bevelgearreducerandsteelwireropeandpulleyhascarriedontheselectionanddesigninthedesignoftheaerialpassengerdevice.Atthesametime,thebrakeandcouplingandaerialpassengerdeviceofdailyuseandmaintenanceareinvolvedandinstructions.Inordertomakeadesignmorereliable,usingthesolidworkssoftwaretodesignpartsofthethreemodelingandfiniteelementanalysis,finallycombiningwiththedesignspecificationsforthecaddrawingsofthedraw.Thedesignofaerialpassengerdevicecanmeetthedesignrequirements.Keywords：Aerialpassengerdevice;planetaryreducer;steelwirerope目录1绪论 顶锥角：根锥角：外锥距：5滑轮结构的设计5.1滑轮设计计算绳索滑轮一般用来导向和支承，以改变绳索及其传递拉力的方向或平衡绳索分支的拉力。5.1.1滑轮结构和材料承受载荷不大的小尺寸滑轮（mm）一般制成实体的滑轮，用、或铸铁（如）。受大载荷的滑轮一般采用球铁（如）或铸钢（如等），铸成带筋和孔或带轮辐的结构。大型滑轮（mm）一般用型钢和钢板焊接结构。受力不大的滑轮直接安装在心轴上使用，受有较大载荷的滑轮则装在滑动轴承（轴套材料采用青铜或粉末冶金等）或滚动轴承上，后者一般用在转速较高、载荷大的情况下。轮毂或轴套长度与直径比一般取为。具有固定轴的滑轮成为定滑轮；具有活动轴的滑轮（随绳索串动改变其位置）称为动滑轮。在本设计中滑轮采用铸钢件铸成有轮辐的结构。5.1.2钢丝绳进出滑轮时的允许偏角钢丝绳绕进或绕出滑轮槽时偏斜的最大角度（即钢丝绳中心线和与滑轮轴垂直的平面之间的角度）推荐不大于。5.1.3滑轮主要尺寸滑轮的主要尺寸如图5-1所示：根据前面所选的钢丝绳直径mm进行设计与计算。下面的主要参数计算公式以及查表主要是根据《中华人民共和国机械行业标准》《起重机用铸造滑轮绳槽断面》里面的公式以及数据确定。图5-1滑轮主要尺寸滑轮绳槽底半径：mm查表取：，一般为这里取：所以滑轮直径：查表取：mm5.1.4绳槽断面尺寸本标准的绳槽半径R是根据钢丝绳公称直径d的最大允许偏差为+7%确定的。钢丝绳绕进或绕出滑轮槽时偏斜的最大角度（即钢丝绳中心线和与滑轮轴垂直的平面之间的角度）应不大于。绳槽表面粗糙度分为两级：1级：um2级：um根据工作情况，选滑轮绳槽半径mm，表面粗糙度级的绳槽断面。标记为：绳槽断面9.0-2JB/T9005.1—1999。具体尺寸参数，如图5-2所示：图5-2绳槽断面图mmmmmmmmmmmmmmmmmm5.2铸造滑轮形式和轴承尺寸根据《中华人民共和国机械行业标准》中的《起重机用铸造滑轮型式、轮毅和轴承尺寸》，进行滑轮形式和轴承尺寸的确定。因为此滑轮为煤矿井下架空乘人装置所使用，考虑到井下环境，以及滑轮所承载的力较大，所以选择JB/T9005.8-1999起重机用铸造滑轮E2型，这种滑轮使用圆柱滚子轴承，承载力大，且对于密封的要求为一般密封、无需内轴套，加工简单。E2型滑轮型式结构如图5-3所示：图5-3E2型滑轮型式结构（1）轮毂尺寸的确定：根据前面计算，可以得知滑轮的最小直径D为400mm。查《起重机用铸造滑轮型式、轮毅和轴承尺寸》表，可以查得D5的尺寸为160mm。所以所选滑轮标记为：滑轮E16×400–160JB/T9005.3—1999轮毂的其余尺寸如表5-1所示：表5-1轮毂尺寸基 本 尺 寸参考尺寸螺栓孔数n螺钉孔数n1D7K7D4D12D15D17D19H12B()F1()D2R5290M12143203252951158.540040016612（2）轴承型号的确定：根据计算的轮毂尺寸，同样查《起重机用铸造滑轮型式、轮毅和轴承尺寸》，可以选择出E2型滑轮所使用的轴承为圆柱滚子轴承，代号为NJ232。其尺寸如表5-2所示：表5-2所选轴承尺寸B3()D5D6E 型滚动轴承代号B()B4D7k7S2E2型宽度125160180NJ232481151092909（3）滑轮技术要求：=1\*GB3①材料：ZG35Mn=2\*GB3②外观：滑轮表面应光滑平整，应去除尖棱和冒口，滑轮不得有影响使用性能和有损外观的缺陷，如气孔，裂纹，疏松，夹渣，铸疤等。=3\*GB3③热处理：滑轮应进行退火处理，以消除铸造时产生的应力。=4\*GB3④尺寸公差和表面粗糙度：加工表面未注公差尺寸的公差等级按GB/T1804中的M级（中等级）；未加工表面粗糙度值按GB/T1031中的um。=5\*GB3⑤形位公差：滑轮的形状和位置公差应符合《起重机用铸造滑轮绳槽断面》中的规定。=6\*GB3⑥装配：装配好的滑轮应能灵活地旋转。滑轮的加工部位（内孔，绳槽表面等）和隔环的外露部位应涂抗腐蚀的防锈油，不加工部位应涂防锈漆。=7\*GB3⑦滑轮的加工部位（内孔、绳槽表面等）和隔环的外漏部位应土抗腐蚀的防锈油；不加工部位应涂防锈漆。5.3本章小结本章主要对滑轮进行了结构设计。主要依据《中华人民共和国机械行业标准》《起重机用铸造滑轮绳槽断面》选取铸钢件铸成有轮辐的滑轮结构。同时对滑轮的主要尺寸、绳槽断面尺寸、铸造滑轮的形式以及轴承尺寸进行了设计与验算。6主要零部件的有限元分析6.1有限元分析简介本章在有限元分析平台SolidWorksSimulation环境下对架空乘人装置部分零部件静力学特性进行研究，分析影响加工质量的关键零件的应力、应变及变形特性，其计算结果可为结构优化和改进提供理论依据。考虑到之前已经对行星减速器高速级输入齿轮轴进行了验算，且此零件是一个十分重要的零件，所以本章同样对行星减速器高速级输入齿轮轴进行三维建模并对它进行有限元分析，已验证我们之前的计算结果同时保证设计的准确性。此外，架空乘人装置的座椅是直接与人接触的零部件，承担着人的重量，之前并没有对座椅的设计进行详细的验算，因此，本章同样选用座椅作为三维建模对象并进行有限元分析。6.2主要零部件有限元分析6.2.1高速级输入齿轮轴有限元分析根据计算可知，高速级齿轮轴主要是太阳轮，其模数为4，齿数为17，齿厚为33mm，创建好模型后，对模型进行简单地受力分析并确定边界条件。根据第四章的分析，齿轮受到一个径向力和一个切向力，因为是直齿轮，所以轴向力为零。根据计算结果，设置径向力为3082N，切向力为8468N。对于轴的固定，假设一种极端状况，轴只受力，不旋转，此时轴的工作情况最为恶劣。因此，在键槽处施加约束，使轴在键槽处固定设置好轴的边界条件后，选择轴的材料，选用轴常用的45号钢作为材料，选好之后，solidworks软件会自动的把参数付给齿轮轴，其参数如表6-1所示：表6-1齿轮轴材料参数属性名称数值单位弹性模量2.09x1011N/m^2泊松比0.269NA抗剪模量8.23x1010N/m^2质量密度7890kg/m^3张力强度6x108N/m^2屈服强度3.55x108N/m^2热扩张系数1.2x105/Kelvin热导率48W/(m.K)比热450J/(kg.K)设置好约束及材料之后，运行，即可得到应力，应变及位移云图。高速输入齿轮轴的应力云图如图6-3所示：图6-3高速齿轮轴应力云图高速输入齿轮轴的位移云图如图6-4所示：图6-4高速齿轮轴位移云图高速输入齿轮轴的应变云图如图6-5所示：图6-4高速齿轮轴应变云图因此可以得出做大的应力应变结果如表6-2所示：表6-2高速齿轮轴应力应变位移结果名称类型最小最大应力应力94.7N/m21.2x108N/m2位移合位移0mm0.1449mm应变对等应变3.8x10-100.0003919346.2.2吊椅限元分析分析吊椅的边界条件，吊椅的上部主要是固定在抱锁器上面，人坐在吊椅的座位上，因此吊椅的边界条件的施加如图6-6所示，将上端面固定，座椅施加800N的力。给吊椅付常用的材料，Q235A，其属性如表6-3所示：表6-3吊椅材料属性属性名称数值单位弹性模量2.12x1011N/m2泊松比0.288NA抗剪模量8.23x1010N/m2质量密度7860kg/m3张力强度3.9x108N/m2屈服强度2.35x108N/m2热扩张系数1.2x105/Kelvin热导率43W/(m.K)比热440J/(kg.K)在最初设计时，设计吊椅的圆柱界面直径为15mm2，座椅下面横梁宽度为12mm，运行，座椅的应力如图6-7所示，图6-7座椅应力图此时可以发现，座椅所能承受的最大应力已经超过了材料所能承受的屈服应力，这样不符合要求，且通过观察，最大应力集中在座椅与杆的焊接处，如图6-8所示：图6-8座椅最大应力图为了改善设计，通过分析，将座椅的杆截面积提高到20mm2，把座椅下横梁宽度增加到18mm，且如图6-5所示，焊接一个斜梁以增加强度。再次运行，吊椅的应力应变以及位移如图6-9，6-10，6-10所示：图6-9座椅应力云图图6-10座椅位移云图图6-11座椅应变云图结果如表6-4所示：表6-4座椅有限元分析结果名称类型最小最大应力应力5.8x10-8N/m21.3x108N/m2位移合位移0mm11.0082mm应变对等应变2.5x10-190.000453182改进后发现，做大的应力已经小于材料的屈服应力，但是最大位移仍然大于了10mm，考虑到应变，已经可以满足我们的设计需要了，因此可以认为符合要求。6.3本章小结本章主要是对架空乘人装置的部分零件进行了有限元分析。有限元分析插件对行星减速器高速输入齿轮轴以及座椅进行了建模与分析。根据软件给出的零件的应力应变以及位移云图的分析表明之前的理论验算完全满足我们的设计要求。结论通过本次设计，了解到架空成人装置及发展趋势，确定了此架空乘人装置的驱动部分的传动方案为电动机带动行星减速器与锥齿轮减速器进行传动。其中行星减速器具有大传动比的特点，锥齿轮减速器具有起到转换传动方向的作用。根据需要，确定该系统的传动比为72.64，查阅行星减速器设计手册，分配传动比为：行星减速器为27，锥齿轮减速器为2.7。对于行星减速器选型二级NGW型的传动结构。设计过程中，对于行星减速器与锥齿轮减速器的齿轮，轴承，以及键均进行了设计计算与强度校核。设计结果均符合设计要求。分析了架空乘人装置的发展现状及发展趋势，阐明了架空乘人装置的组成和工作原理。对整机总体方案进行了详尽的论证，为架空乘人装置各个部件进行了选型设计及计算。重点完成架空乘人装置的电机减速器的选型、钢丝绳的选型与计算、承载托轮和压轮的设计计算、尾轮装置的设计计算、张紧轮的设计计算、吊椅设计计算以及紧急停车装置的设计计算。参考文献[1]王洪欣、李木、刘秉忠主编，《机械设计工程学》，1出版社，2004年1月[2]唐大放、冯晓宁、杨现卿主编，《机械设计工程学》，1出版社，2004年1月[3]成大先主编，《机械设计手册》单行本机械传动化学工业出版社，2000年[4]卜炎主编，《机械传动装置设计手册》上册机械工业出版社，1999年4月[5]卜炎主编，《机械传动装置设计手册》下册机械工业出版社，1997年12月[6]中国机械工程协会、中国机械设计大典编委会、朱孝录主编，《中国机械设计大典》第四卷江西科学技术出版社，2002年1月[7]起重机设计手册编写组编，《起重机设计手册》机械工业出版社，1977年8月[8]成大先主编，《机械设计手册》单行本弹簧•起重运输件•五金件，化学工业出版社，2004年1月[9]吴宗泽主编，《机械零件设计手册》机械工业出版社，2003年11月[10]成大先主编，《机械设计手册》单行本轴及其联接，化学工业出版社，2004年1月[11]清华大学吴宗泽，北京科技大学罗圣国主编，《机械设计课程设计手册》第3版高等教育出版社，2006年4月[12]东北大学《机械零件设计手册》编写组编，《机械零件设计手册》第三版下册冶金工业出版社，1994年4月[13]编辑委员会编，《现代机械传动手册》机械工业出版社，2002年3月[14]吴宗泽主编，《机械零件设计手册》机械工业出版社，2004年[15]吴宗泽主编，《机械设计实用手册》第二版，化学工业出版社，2003年10[16]单辉祖主编，《材料力学》北京，高等教育出版社，1999年[17]C.Yuksel,A.Kahraman,Dynamictoothloadsofplanetarygearsetshavingtoothpro.lewear,MechanismandMachineTheory(2004)[18]R.G.Parker,S.M.Vijayakar,T.Imajo,Non-lineardynamicresponseofaspurgearpair:modelingandexperimentalcomparisons,JournalofSoundandVibration(2000)[19]R.Maliha,U.C.Dogruer,H.N.Ozguven,Nonlineardynamicmodelingofgear-shaft-disk-bearingsystemsusing.niteelementsanddescribingfunctions,JournalofMechanicalDesign(2004)翻译外文资料原文StrategiesforAutomatedMaintenanceofBeltConveyorSystemsProf.dr.ir.GabrielLodewijks

DeIftUniversityofTechnology,theNetherlandsSUMMARYThispaperdiscussesautomationofmaintenanceofbeltconveyorsystems,inparticularofidlerrolls.Automationofmaintenanceisapromisingalternativeforoutsourcingmaintenance,inparticularwhenlookingattheefficiency,accuracy,andcosts.Inordertooptimisemaintenanceefforts,theconceptofintelligentmaintenanceisintroduced.Thepoweredmaintenancetrolleythatcantravelautonomouslyoverthestructureofabeltconveyorisadaptedasaplatformofthemaintenancesystem.Onthistrolley,dataacquisitionequipmentforvibrationanalysisisinstalled.Dataminingcanbedoneeitheronboardofthetrolleyorinacentralcomputerdependingonthemaintenancestrategy.Theoptimummaintenancestrategyisdeterminedbyalogisticsimulationmodelthataccountsforthelay-outofthebeltconveyoritselfandtheaccuracyoftheinformationontheremaininglifetimeofitscomponents.INTRODUCTIONTodaymoreandmorecompaniesoutsourcemaintenanceinanattempttobalancethebudgetandreducethenumberofpermanentstaffmembers.Outsourcingmaintenancehoweveronlyworksifthecompanythattakesovermaintenanceemployswell-trainedandexperiencedpersonnelthatstaysonaspecificjobforaconsiderabletime.Unfortunately,realityisdifferentandmanycompanieshavepoorexperienceswithexternalcompaniesperformingmaintenance.Ingeneral,maintenanceonbeltconveyorsystemscanbedividedintoinspectionorconditionmonitoringofthetotalsystemandreplacementand/orreparation(inshortservicing)ofitscomponents.Mostproblemsexperiencedwithoutsourcementofmaintenanceareassociatedwiththeinspectionorconditionmonitoringofasystem.Itisnottrivialtoaccessthestatusofsometimesmovingcomponentsofabeltconveyor.Thesameexperiencedpersonshouldthereforecarryoutinspectionsonaregularbasis.Toovercomeoperationalproblemscausedbyalackofexperienceofexternalmaintenancepersonnel,theinspectionofbeltconveyorcomponentscanbeautomated.Inthiswayknowledgeofforexamplewearratesandreplacementschedulescanbebuiltupinadatabasesystem.Theexternalmaintenancecrewthencanbeusedtoreplacethewornoffcomponents.Alternatively,replacementofcomponentscanbeautomatedaswell.Thispaperdiscussesstrategiesandtechniquesforautomatedmaintenanceofbeltconveyorsystems.Section2definestheconceptofintelligentmaintenance,Section3discussesexistinginspectionsystemsthatcanbeusedinautomatedmaintenancesystems.Section4discussesmeansofassessingthestatusofrotatingcomponentsofbeltconveyorsbasedonvibrationbasedmonitoringconcepts.Section5presentsacasestudyandsection6finallyliststheconclusionsandrecommendations.INTELLIGENTMAINTENANCEMaintenanceonbeltconveyorsystemscanbedividedinconditionmonitoringofthetotalsystemandservicingofitscomponents.Conditionmonitoringisdefinedasthecontinuousorperiodicmeasurementandinterpretationofdatatoindicatetheconditionofacomponenttodeterminetheneedforreplacementorservicing.Conditionmonitoringthereforedealswiththeacquirementofdata(dataacquisitionorDAQ)fromsensors,theinterpretationofthatdata(dataminingorDAM)andwithtakingcorrectiveactions(ACT)oncomponentsthataretofail,thuspreventingfailsystemsfromdevelopingandpropagating.Thebasicconceptofconditionmonitoringistoidentifysubtlechangesinoperation,suchasincreasedvibrationlevels,thatindicateamechanical(orelectrical)problemisstartingtodevelop.Theseearlymessagesprovidemoretimetoplanformachinedowntimeandrepair.Therearefourtypicaltypesofmaintenance:preventivemaintenance:calendarbased,i.e.activitiesareplanneddependingonworkinghoursoratcertaintimeintervals(scheduledmaintenance);itmaybebasedonobserveddeteriorationofcomponents;nothingisrepairedbutpreventivejobsaredone.randommaintenance:opportunitybased,i.e.maintenanceisdonewhentheopportunityarises;thedecisiontomaintainacomponentbasedonopportunitiesmayormaynotbetriggeredbytheconditionofacomponent.correctivemaintenance:emergencybased,i.e.repairingwhenacomponentmalfunctions;thismaycauseageneralshutdownofthesystem;therepairactivitywasnotscheduledbeforehand.predictivemaintenance:conditionbased,i.e.componentsarebeingmonitoredandwhenirregularfactorsarediscovered,onewaitsuntilamaintenanceopportunityarises;itisaplannedandcorrectivemaintenance.Fromtheabovegivenfourtypesofmaintenanceitisclearthatonlyapredictivemaintenanceconceptqualifiesforapplicationinanintelligentmaintenancesystemthatenablesmaintenanceautomation.Intelligencehereisdefinedastheabilitytomakedecisionsbasedoninformationgatheredthroughsensorsintheequipmentorprovidedbythecontrolsystemofthetotaltransportsystem.Appliedtobeltconveyorsystemstheinformationgatheredfromasystemisinformationonthelifeexpectancyofindividualcomponentsasforexampleidlerrolls.Thisinformationleadstoadecisioneithertoinspectacertainidlerstationanditsrollsmorefrequentlyortochangearollforanewroll.Repairinginfactheremeanschangingonerollforanother.Whetherornotarollcanberepairedandtheeffectofthatonthebeltconveyor’sperformanceisoutsidethescopeofthisstudy.Themainissueinthisstudyisthequestionhowanautomatedinspectionstrategyisaffectedbytheaccuracyofthedataacquired.Intheorytherearetwoouterlimitsinpredictivemaintenance.Thefirstisthatnoaccurateinformationoftherollsisavailableatall,basicallymeaningthatanassessmentoftheremaininglifetimeismadepurelyonthebasisofhistoricaldataprovidedbytherollorbearingmanufacturers(predictivemaintenancebasedonstatistics).Thesecondisthatduringinspectionveryaccurateinformationonthestatusofrollsisgeneratedenablinganaccurateassessmentoftheremaininglifetimeofanindividualroll(predictivemaintenancebasedondata).Alogisticsimulationmodelismadetodeterminetheeffectoftheaccuracyofdataacquiredonautomatedinspectionstrategies.ThismodelisdiscussedinSection5.EXISTINGINSPECTIONSYSTEMSOneproblemfacedwithinspectionorconditionmonitoringofcomponentsofbeltconveyors,includingthebelt,pulleysandidlerrolls,isthattheyrotate.Sincetheconditionofcomponentslikerollsandpulleyscanonlybeassessedwhentheyarerotating,onlyconditionmonitoringsystemsbasedonvibrationanalysisoracousticalmonitoringcanbeused.Theoppositeholdsforthebelt.Thebelt’sconditioncanonlybeinspectedwhenthebeltconveyorsystemisnotoperating.Eitherway,aninspectorhastowalkthefulllengthoftheconveyortoinspectitscomponents.Anassociatedproblemisthatpulleysmaybefarapartfromeachotherorthattheconveyorhasagreatlength.Toeaseinspectioninthesecasesapoweredmaintenancetrolleycanbeusedforinspectionpurposes.Theconceptofapoweredmaintenancetrolleyisnotnew.Anearlyexampleofamaintenancetrolleyusedonabeltconveyorsystemwasthetrolleyusedonthe100kmPhosboucraaoverlandsystembuiltbyKruppinthe70-tiestotransportrawphosphateacrossadistanceof100kmfrominsidethewestSaharaacrossadesertofstonestotheloadingpointonthecoast.Thislong-distanceconveyorsystem,consistingofbeltsystemswithcentredistancesof6.8to11,7km.appliedamaintenancetrolleyconcepttoallowforinspectionalsoseeFigure1.TheKrupp-designturnedouttobeoccasionallyliabletoinstability.Figure1PoweredmaintenancetrolleyonKruppsysteminSahara.ArevitalisedversionofamaintenancetrolleyisshowninFigure2.Thisconcept,designedanddevelopedbyCKITofSouthAfrica,isquiterobustandstable.Ithasbeeninstalledonanumberofpipeconveyorsystems,bothinsideandoutsideSouthAfrica.Ithasthreeinspectionplatformsandissupportedonsixpoints(verticalandtransversedirection).Currentsystemsarepoweredfromthemainplatformbycombustionengines.Today’strolleysareallmenoperatedandinspectionandservicingworkiscarriedoutbymenaswell.Figure2

CKITconceptofpoweredmaintenancetrolleyTheconceptofthemaintenancetrolleyasdevelopedbyCKITisadaptedinthisstudyastheplatformforthefurtherdevelopmentofafullyautomatedmaintenancefacility.Thisdevelopmentisdividedinthreestages.Thefirststagewillbethedevelopmentofamaintenancerobotonthetrolley,enablingbothautomatedinspectionandservicing.Thedesignofsucharobot,whichisaresearchprojectcarriedoutatthesectionofTransportEngineeringandLogisticsofDelftUniversityofTechnology,isnotconsideredinthispaper.ThesecondstageistheimplementationoftheautomatedinspectionroutinesaswillbedescribedinSection5.Thethirdstageisthefullintegrationoftheautomatedmaintenancetrolleyinthetotalsystemscontrolsystem.DATAACQUISITIONANDMININGConditionmonitoringtechniquesgenerallyincludeoneorseveralalarmsthatgooffwhenaworkingpointisexceededorwhenatrenddeviatesfromtheexpectedvaluesintime.Referencesoftheworkingpointsofsignalsareprovidedbyknowledge-basedsystemsandnotbycomparisonwithamodelofthesystem.Signalsareacquiredbysensorsystems.DATAACQUISITIONTECHNIQUESChoosingtheproperdataacquisitiontechniquehasalargeimpactontheefficiencyofthemaintenancestrategy.Good,reliablemeasurements,aswellasproperanalysesoftheresultsofthosemeasurements,areessentialforreliableactionsofthemaintenancesystem.Forrotatingcomponentsmostoftenasignal-basedconditionmonitoringsystemisappliedbasedonvibrationand/oracousticsmeasurementtechniques.Anotheroptionisusingforceandtorquemeasurementsasabasisforconditionmonitoring.Forrotatingcomponentshowever,theapplicationofwirelesstorquemeasurementequipmentisrequired,whichisexpensive.Itissuitableasatemporarymonitoringsystembuttodaystillnotfitforlarge-scalepermanentmonitoringsystems.Spectralanalysisisanimportanttoolinvibrationbasedconditionmonitoring.Ingeneralvibrationbasedmonitoringmeansmeasuringaccelerationlevelsusingthree-dimensionalaccelerometers.Thesignalacquiredfromthesesensorsthereforeisaccelerationasafunctionoftime.InaspectralanalysisthissignalistransformedfromthetimedomaintothefrequencydomainbyapplyingaFastFourierTransformtechnique(FFT).Withthesignalinthefrequencydomaintherootsourceofthesignalcanbeeasilydetermined.Theanalysisofthespectraldensity,whichrelatestheenergyinthevibrationsignaltoaspecificfrequency,isagoodmeansofdeterminationoffaultsadvancingintime.Vibrationanalysisisoneofthemainformsofconditionmonitoringand,ingeneral,isoftenappliedintheindustry.Thespectraldensityofvibrationlevelsofagoodworkingcomponentwillgenerallybelow.Whenwear-outoccurs,orwhenloadsappearonspecificcomponents,thensomesmallbutnotablechangeswilloccurinthedynamicalbehaviourofthecomponent.Bymakingthesechangesvisibleandanalysingthem,adiagnosisoftheproblemcanbemade.Themonitoringtechniquesusedinpracticecanbedividedintotwomaincategories:signalRMS(RootMeanSquare)basedmonitoringdetailedsignalspectrumbasedmonitoringAcousticalanalysisstronglyresemblesvibrationanalysis.Dataminingfollowsafterdataacquisition.Dataminingconsistsofthreemainsteps.Thefirststepisthedetectionofdefectsthatisbasedonknowledgeofthedynamicsofthecomponentsmonitored.Thesecondstepisdataprocessing,transformingtheacquireddataindatathatisbetterfitforanalysis.Thethirdstepistheactualanalysisofthedataitselfrequiredtomakeadecisiontotakecertainactions.DATAMININGI-DETECTIONOFDEFECTSInthispaperthemainfocusisonbearingssincebearingsare,byfar,themajorsourceofthemalfunctioningofrotatingcomponentsincludingidlerrolls.Obviously,idlerrollscanalsofailasaresultofshellwear.Themechanismofshellwearhoweverdiffersfrombearingwearandassuchrequiresadifferentdetectionprocedure.Inthispaperonlythedetectionprocedureforbearingfailuresisdiscussed.Therearemanywaysinwhichbearingdynamics,whichmayleadtodefects,canbeclassified.OneofthemisbydefiningcomponentfrequenciesasafunctionoftherotatingspeedfrotandofsomegeometryparametersincludingthenumberofrollingelementsN,thediameteroftherollingelementsD,thecontactangleφ,andthebearingpitchdiameterP.Thefrequenciesidentifyingthefourmaindynamiceffectsinbearingsare:thecagerotationalorthefundamentaltrainfrequencyfcage:theinnerringorballpassinnerringfrequencyfir:theouterringorballpassouterringfrequencyfor:therollingelementorballspinfrequencyfre:Bearingdefectsshowupasanincreaseinspectraldensityfordefectrelatedfrequencies.Bearingdefectfrequenciesarearesultofimpactsduetotherollingelementspassingoverthedefectsastheypassthroughtheloadedzoneofabearing.Thedefectfrequencies,exceptforthecagerotationalfrequency,aresurroundedbysidebandsinarealsignal.Ifthedefectfrequencyoriginatesfromasignalthatpassedtheloadedzone,thereareksidebandswherek€N.Thenextfrequenciescouldappearinaspectrum:outerringdefect:at

innerringdefect:atrollingelementdefect:atcagedefect:atwherenisthenumberofharmonics.Asthedefectissmaller,themeasuredaccelerationsignalismorelikeapulsethanlikeasinewaveandtheenergycontentdecreaseswhilethedefectfrequencyincreasesinthespectrum.DATAMININGII-TECHNIQUEOFDATAPROCESSINGBandenvelopingistheprocessoftransformingavibrationsignalwithsmallsuperimposeddisturbancesintoisolateddisturbanceinformation.Themainreasonforusinganenvelopeofasignalisthatonecandetectdevelopingdefectslikesmallcracksinaveryearlystage.Theprocessofbandenvelopingconsistsofthreesteps:high-passfiltering,rectification,andlow-passfiltering.Astheenergyofadisturbancecomparedtotheenergyofthesinewaveisverylowthenthepulseishardlydetectableinthefrequencyspectrum.Thefirststepthereforeistouseahigh-passfiltertofilteroutthe(lowfrequency)sinusoidalcomponent.Theremainingsignalcontainsonlytherepetitivedisturbances.Thesignalthenisrectifiedandpassedthroughalowpassfilter.Thepeakinthefrequencyspectrumthenrepresentsthedefectfrequencyofthecomponentthatisdefective.Thepulseslosethehighfrequencycomponentsbecauseofthelow-passfilter.Therepetitionperiodhoweverremains.DATAMININGIII—DATAANALYSISDataanalysiscanbequitecomplicated.IfthescopeofanalysisisrestrictedtobearingsandthefouridentifiedpossibledefectsaslistedSection4.2,thentheprocedurecanbeasfollows.Firstthefrequencyspectrumisscannedforanomalies.Ifpeaksaredetectedinthisspectrumthentheequations(5)till(8)canbeusedtoidentifytherootcause.Knowingtherootcause,forexampleouterringproblems,thentheacquiredsignalleveliscomparedtoadatabaseidentifyingtheseriousnessofthedefect(s)anddeterminingapropercourseofaction.Partofthelatterdeterminationisbasedoncommonif-then-elsestructuresenablingastructured(andautomated)analysisofpossiblecausesandfutureeffectsonoperation.Ifmorethanonepossiblecauseforadefectisknown,forexampleaspecificsignalcanidentifyadefectinabearingbutalsointhesensoritself,thenconfidencefactorshavetobeappliedtorule-outthemostpossiblecause.ANINTELLIGENTMAINTENANCECONCEPTInthissectionaconceptforthelogisticcontrolofanintelligentmaintenancesystemisgiven.Themaintenanceconceptisbasedonthepredictivemaintenanceconcept,usingeitherstatisticsortheresultsofadetaileddataanalysis,whichwasintroducedinSection2.Thetechnicallay-outofthemaintenancesystemisbasedontheapplicationofanautomatedmaintenancetrolleyincludingamonitoringandservicingrobotasdiscussedinSection3.Thedataacquisitionandminingtechniquesusedwerediscussedintheprevioussection.MODELInthelogisticmodelanumberofelementsaredetailedincluding:thebeltconveyoritselfthebearingsthemaintenancerobottheinspectionrequirementstheservicingaspectsandthedataanalysisBeltconveyorInthemodelthebeltconveyorcanbespecifiedintermsofitslengthandtheidlerpitches.Thenumberofidlerstheniscalculatedautomaticallyassumingthatthepitchisconstant.Itisassumedthatacarryingidlerhas3rollsandareturnidler2.Eachrollhastwobearings,whichhaveaminimumlifelengthasspecifiedbytherollandbearingmanufacturer.Thenumberoftherollsthatfailbeforetheminimumlifelengthcanbespecified.Asastandardthisnumberis10%.Ifonasystemusedrolls,insteadofnewrolls,areinstalledthentheprogramaccountsforthiseffectbyallocatingremaininglifelengthstoindividualrolls.BearingsThelifelengthofaspecificbearinginarollisallocatedviaatabularizeddistribution.Underandupperlimitscanbespecifiedassumingauniformdistribution(minimumandmaximumlifelengthasspecifiedbyrollandbearingmanufacturer).Thechanceoffailurebeforereachingtheminimumlifelengthcanbespecified,againaccordingtoauniformdistribution.Alldistributionscanbechangedforthemiddleandthesiderollsofthecarryingaswellasthereturnidlersets.MaintenancerobotThemaintenancerobottravelsoverthestructureofthebeltconveyorinthedirectionfromtheheadtothetailataconstantspeed.Itisassumedthattherobotisavailable24hoursperday.InspectionOninspectionofanidlerset,thetotallifelengthestimationofanindividualrollisbasedeitheronhistoricaldata(statistics)orbasedonaccuratevibrationmeasurements.Thetotalinspectiontimeconsistsofafixedset-uptimeandtheinspectiontimeitself.Allrollsinoneidlersetareinspectedatthesametimeusingamultiplesensorrobotarm.ServiceIfthemaintenancerobotdecidestochangearollthenitisalwaysreplacedbyarollofthesametype.Thetotalreparationtimeconsistsofafixedset-uptimeandthetimeforrepairingor,inthiscase,changingouttheidlerroll.EstimationofresiduallifetimesTherobotestimatesthelifetimeofarollusingaFourieranalysisofthevibrationsintheroll.Forsimulationofthisprocess,amodelwith2parametersisused.Theestimationisasamplefromanormaldistributionwithasmeanthelifetimeoftheroll.Thedeviationofthisdistributiondeterminestheaccuracyoftheestimationandiscontrolledbythefirstparameter(d).Withthesecondparameter(f),abiasisintroduced.Theestimatorbecomesconservative,biasedtowardsunderestimatingthelifetime.TheestimatorS1isdefinedby:S1=L+d(L-A)X-f(L-A)WhereL,LifetimeoftherollA,CurrentageoftherollX,Randomvariable,sampledfromaNormal(0,1)-distributiond,Deviation,asfractionoftheresiduallifetimef,Safetyfactor,asfractionoftheresiduallifetime

AsampleofXisdrawnforthenormaldistributioneachtimeestimationisrequired.Iffequalszerothenestimatorisunbiased.Theprobabilitythattheestimatoroverestimatesthelifetimeis50%.Withf>0theestimatorbecomesbia