ASummaryofSmall-sizeExcavatorsHomeandAbroadI.ThebriefintroductionofhydraulicexcavatorPartssuchasthehydraulicexcavatorisbyengine,hydraulicsystemandworksdeviceandwalksdeviceandelectriccontroletcareformed.Thehydraulicsystemisformedbyhydraulicpump,controlvalve,hydrauliccylinder,hydraulicpressuremotor,piperouteandfueltanketc.Theelectriccontrolsystemincludessupervisiondish,motorcontrolsystem,pumpbrainandvariouskindsofsensorandsolenoidvalvesetc.Thehydraulicexcavatorisgeneralbytheworkdeviceandturnsroundthedeviceandwalksdevicethreeismostlyformed.Accordingtohisconstructionanduse,wecandifferentiate:manykindsoftypessuchascaterpillartreadtype,tyretype,walktype,fullhydraulicpressure,halfhydraulicpressure,turnsroundentirely,notturnsroundentirely,utilityversion,mouldforaspecialpurpose,thejoiningwithahingetypeandarmtypestretchedoutanddrawnbacketc.Theworkdeviceisdirectlyaccomplishingthedevicethatexcavatestheassignment.Ithasbeenjoinedwithahingebymovesthearm,fightsthepoleandshovelsthefilletcthreeparts.Movingthatthearmrisesandfallsandthepolefoughtstretchesoutanddrawsbackandshovelingfightingmovesallwithmovingbackandforthtypetwoeffecthydrauliccylinderscontrol.Inordertosuittheneedsofvariousdifferenceconstructionschoolassignments,thehydraulicpressureexcavatorcanbejoinedinmarriageloadingmanykindsofworkdevices,ifexcavatingandmanykindsofschoolassignmentmachinesandtoolssuchasliftingjob,loading,leveling,clampandpushessoilandshockhammeretc.Turningroundandwalksthedeviceistheorganismofhydraulicpressureexcavator,uppersettinguppower-ondeviceandtransmissionsystemofturntable.Theengineisthepowersupplyofhydraulicpressureexcavator,andadoptsdieseloilwillalsocanmodifytheelectromotorintheconvenientplacemostly.Thehydraulicdrivesystembywayofthehydraulicpumpwiththeenginethemotive-1-forcetransmissiontohydraulicpressuremotorandhydrauliccylinderetcactuator,thepromotionworkdevicemoves,thusaccomplishesthevariousschoolassignments.TakemorePV-200'smouldhydraulicpressureexcavatorsofuseinbuildingsiteastheexample.Thismachineadoptsthetypetheopeningcenterloadofadvancedversiontobepassedfeelingsystem(OLSS).Thissystemiswithobliqueofcontroltypeobliquethemethodofangle(exportvolumeofflow)variableplungerpump,andreducedthepowerdeliveryofengine,thusreducestheoilconsumptionburnt,andisonekindofsavingenergymouldsystem.Thecharacteristicofthiskindofhydraulicsystemis:thefixedtorqueiscontrolled,anditisunchangeabletokeepthehydraulicpumpdrivetorque,andyearabsolutelycontrolcanreducetheoff-loadinglossofschoolassignmenttime;Oilcapacityiscontrolled,andtheexportvolumeofflowofhydraulicpumpinthetimeofcanreducingneutralgearandfinecontrolreducesthepowerloss.Thehistoryofthefirsthandexcavatorwaspublisheduptonowtohavemorethan130years,andwentthroughfromthesteamdrivefilltoturnroundthatthemachineryturnsroundthedevelopingthecoursestepbystepofthecompleteautomatichydraulicpressureexcavatorofexcavatorandapplicationmechanicalandelectricalliquidintegrationtechnologytopowerdriveandtheinternal-combustionenginedriveinthetime.Theapplicationowingtothehydraulictechniquehadtojoininmarriageonthetractorloadinghydraulicpressuretoanti-thetypehangingwhichshoveledmachineryinthe1940’s,anddevelopingoutthepullingtypeattheinitialstageofinthe1950’swithmiddleperiodinsuccession,toturnroundthefullhydraulicpressureofhydraulicpressureexcavatorandcaterpillartreadtypeentirelymechanical.Initialstagethetrialhydraulicpressureexcavatoristhehydraulictechniquethatadoptsplaneandmachinetool,lackingthehydraulicpressurecomponentthatissuitableinthemechanicalvariousoperatingmodes,itisstableinadequatelytomakethequality,andnecessaryisnotcompletelyyet.Frominthe1960’s,thehydraulicpressureexcavatorisenteredthepopularizationandinvigorousdevelopmentstage,andmechanicalmanufacturingplantandthebreedofeachcountryincreasesveryfast,andtheoutputisrapidlyincreased.83%ofthemechanicalgrossoutputwasoccupiedtohydraulicpressureexcavatoroutput,andiscloseto100%atpresent1968-1970certainperiod.20thcentury80~90'ssmallmechanicaldeviceinconstructionandsooninmunicipalengineering,transportation,pipelinehasdisplayedabiggersuperiorityandcanrapidly-2-develop.Thesmallexcavatorforsavedthemanpower,thephysicalresourceintheseprojectsmakesthesmallexcavatormainlytouseinthecitytheconstructionconstructionandgenerallyleftabiggercontribution,graduallybecameinthecityconstructiontohavetherepresentativeconstructionmachinery.Thesmallexcavatordevelopmentmainlyreliesontheurbanconstructiondevelopment,becausecitytransformation,constructionconstructionmore,therequestconstructiontimeshort,theconstructionmachineryaffectssmall,safe,thelowpollution,theradiusofgyrationtotheenvironmentissmall,isadvantageousfortransportsaswellashaswiththecitysceneryappearancecoordinationoutwardappearance,thesmallexcavatorhassatisfiedthecityeachkindofworkrequest,canmaximumlimitdisplayitsproductivityinthecitynarrowworkingspace,thereforehastheuniquesuperiority.1.ThedevelopmentofsmallexcavatorsThesmallexcavatormainlyusesinthecitytheconstructionconstructionandthegeneralhousingrepairsandmaintainsandsoonthework,therequesthasthegoodoperatingperformanceandtherotationperformance.Initialsmallexcavatorbytiretypeprimarily,becausethetiretypewalksthenaturalinthesoftgroundandthepassingdifference,afterwardsgraduallybythemarchingsubstitution,andinmovedthearmstrutorganizationplacetoincreasetherotationorganizationabout,enabledtheentireworkequipmenttherelativeorganismtocarryonswings,completedthetrenchsidewallexcavationrenovationworkbehind,butthiskindofsmallexcavatorexcavationscopewassmall,cannotrealizethematerial.Hereafter,thesmallexcavatorincreasedupsidehasrotatedtheorganization,hassolvedbehindthemetialandsoontheproblem,enhancedtheexcavatoroperatingperformance,formedthesmallexcavatorthebasicstructure.Afterwards,thesmallexcavatorintheradiusofgyration,behindthefieldofvision,movedaspectandsoonarmelevationangle,machinecapabilityhasthefurtherimprovement,developsforthepresentstandardtype.2.TechnicalprogressesSmallexcavatorworkingconditionsmajorityofincity,inordertopreventwalkswhendamagestheroadsurface,startsfromthe80'stousetherubbercaterpillarband,andgraduallyobtainsthepopularization.Arubbercaterpillarbandheavywheeliswhentheinternalironcircuitboardthemovement,thehardcircuitboardjointplaceandtheheavywheelcontactfallstotheground,becomeswalksthedestructionroadsurfacemainreason.Beforeusesthewidthshapeironcircuitboard,arubbercaterpillarbandheavywheeldiameterisbigger,thereforewhenapproachestheground,thisslitchangesinabigway,createsthecaterpillar-3-bandtotheroadsurfacedestruction.Thesupersmallexcavatoruseandthebeforesameheavywheel,onlywasthehardcircuitboardwhichinthecaterpillarbandusedchangesnarrowly,thereforewhencontactedthegroundtheslitchangesslightly,reducedtothedamageofground.Rearareathesmallrotationexcavatorrotationrearpartsizeisextremelysmall,inordertoguaranteetheexcavatorworkthestability,musthavetheenoughcounterweight,andindoesnotincreasethemechanicalweightunderthepremise,usesincreasesthecaterpillarbandlengthandwidensthechassisandsoontheeffectivemethod.But,thechassiswidthistransportedthetruckwidththelimit,forsolvesthisproblem,hasusedViCTASinthesupersmallexcavator(Vio-CrawlerTechnologybyAdvancedStability)thetechnology.3.ComfortablenessThesmallexcavatormajorityofsealscab,hasnotrainedwhenthechairfrequentlydripswetbytherainseeps.Inordertosolvethisproblem,theusesurfaceandtheinteriorgatherapeacefulfatrubberbodytomanufacturehasnotsewntheseamthechair,cannotagainfromsewtheseamplacedestruction,thedurabilityalsocanenhance,becomesthecompletewaterproofingchair.(1)Thesmallexcavatorhasthewidespreadserviceablesmallexcavatorvolumesmall,mobileisflexible,extremelyissuitableforworkandsooncitieseachkindofpipelining,foundationconstruction,publicutilitiesaswellashouseservice.Thesmallexcavatorcompactvolume,thespecialdesignenableitstocarryontheworkintheenvironmentwhichthelarge-scaleexcavatorisunabletoconstruct.(2)Thesmallexcavatorhasthemulti-purposesmallexcavatortruemeritisithasmulti-purpose.Thesmallexcavatorcaninstallmanyauxiliaryworksmachinesandtools,liketheinstallmentbrokenhammer,thehydraulicpressurepliersuseinthelightweightdemolisionwork,installsaclamptouseintoeliminatethework,installsthedrum,theplateusesinthetrenchtofillinburiesthecompaction,theinstallmentturnsonlathedigsdrillsusesinthedrillhole,thelifthookusesintohoistupheavyitemandsoon.(3)Thesmallexcavatorisadvantageousforthetransportationandoneofshiftworklocationsmallhydraulicpressureexcavatormarketrapidexpansionreasonsshouldbelongtoitssizeandtheweight.Thesmallexcavationfunctionconvenientlyshiftsineachjoblocation,thesmallexcavatordoesnotneedthelarge-scaletrailerperhapstheheavy-dutytruckcarriesonthetransportation,thesmalltransportmeansmaydeliver.Likethisnotonlycanfacilitate-4-thetransportation,butalsomaygreatlyreducethemachinethecartageexpense.(4)Smallexcavatorbrightworkcharacteristic:Therearpartradiusofturnforthezerodesign,causesthesmallexcavatornottoneedintheworkspacelimitedenvironmentmeanindustrytimeexcavatoroperatortoconsiderthejoblocationis,whetherthusenabletheoperatortohavetheobstacletohindertheexcavatortherotationtosufficewhollyabsorbedtothescoopoperation,thishasalsopreventedaroundthejoblocationthebuildingaswellastheexcavatorowndamage.Thesmallexcavatorpriceischeap,thecostrecyclesquickly.Slightlydigstakethe6tlevelastheexample,American,theEuropeandatebrandmachinepriceabout400,000Yuan,SouthKorea'smachinepriceabout320,000Yuan,thedomesticallyproducedmachinepriceis30~320,000Yuansomebrandsislower;Butthe20tlevelcenterdigsthepricein70~1millionYuan.Thehigherinvestmentrepaymentratecausesthesmallexcavatordeeplythegeneralcentersmallearthworkconstructiontocontractowner'swelcome.Thesmallexcavatortechnologicaldevelopmentcompliedwiththeglobaldiversificationjoblocationthedemand,hasexperiencedmorethan30yearshistorysuccessionalvariationprocess,passesthroughtheunceasingimprovementconsummation,inaspectandsoontechnicalperformance,jobfunction,workefficiency,security,environmentalprotection,energyconservationandmaintenancemaintenancehadthelargescaleenhancement,hasformedthequiteconsistenttechnicalstandardandtheworkstandard.Mainlymanifestsinfollowingseveralaspects:(1)Thetaillessrotationandmovesthearmdeflectiontechnologytotakeslightlydigsthebasicconcepttomovethearmdeflectionandthetaillessrotationfunctionlaterperiodpromotesinthe1990sfacetheworldmarket.Movesthearmdeflectionintheorganismfrontpart,butdoesnothavetheorganizationtobeabletorealizeislocatednearbythelowerpartofwallthedirectexcavationworktohavefrequentlytomovethefuselage.Thetaillessrotationstructureapplication,causesitwhentheneckoflandworkdoesnotneedtoworrytherearpartthecollision.Thetaillessrotationstructuraldesigndifficultyliesinrotatesintheplatformthegeneralarrangement,thedynamicsystemthermalequilibriumsolutionaswellastheentiremachinestablesolution.Butmovesthearmdeflectionorganizationthedesigndifficultytolieinanarticulationpositionthedeterminationandthehingebodymanufacturetechnology.(2)Newhydrauliccontroltechnology-5-Thenewhydrauliccontroltechnologyshouldhavetheworkefficiencyhigh,theserviceabilityisgood,hasthegoodefficiency,maycarryonthehighefficiency,thepowerfulwork.Thenewfluidenvironmentcompatibilitypressesthesystemnottoshoulderthesizetheinfluence,completelyneedstheoilofthehydraulicpressuresystem,thecurrentcapacityaccordingtothecontrolhandlescopedistributionpoint,definitelymaydefertooperator'sintentionwitheasetocompletethework.Atthesametime,becausetheengineloadissmallmayavoidthecurrentcapacitythesenselessloss,canrealizeslightlymovestheoperationandthecompoundoperation.Thenewhydrauliccontroltechnologyapplicationalsocanincreasethedynamicoutput,enhancestheworkspeed,reducesthefuelconsumption.(3)SecurityperformanceHasthestrictlegalruleintheEuropeanmarketandtheNorthAmericamarkettothesecurity,theequipmentsecurityperformancecangivetheoperatortoprovidetherelievedworktheenvironment,enhancesoperator'ssecurity.ThesmallexcavatorsecurityperformancemainlymanifestsinthecabROPS/FOPSdesignbelow,shouldsatisfytheperformancerequirementinthecabexperiment:②Maysatisfymustanti-load;Mainlymanifestsinthepower,thelowoilconsumption,cleanlydischargestheengineintheapplication.ThenewengineshouldsatisfytheAmericanEPATier2standardandtheEuropeanEUstandard,willcausetheenvironmentalpollutionthecompoundtodischargethecontrolinthethreshold.Thenewenginesimultaneouslyreducedthevibrationandthenoise,isbeneficialtotheenvironmentalprotectionandoperator'shealth.(5)Man-machineprojecttechnologyThecabconformstotheman-machineengineeringprinciple,internalspacious,fieldofvisionopen,modellingartistic,theeaseofoperation,reduceseffortthemeasuringappliancedemonstrationdirect-viewing,isaccurate,canprovideonekindofcomfortableoperatingenvironmenttothepilot,fullyreducespilot'sweariness.(6)ServicesthemaintenancetechnologyMaintainsfromthecurrentmaintenancetotheregularinspectionservice,thesimplificationoperationisextremelyessential,canenhancethemachinethereliability,makesthemachinethroughouttomaintainthegoodcondition.Mustcausethedailyinspectionside,-6-therealizationnottoneedwiththeaidofthetoolassoonastotouchthetypeoperation.Maintenancerepairthenquicklydndsimplely,butfastcarriesontheinternalsparepartandthesysteminspectionandtheservice.Moreover,inthedesignmustfullyconsiderpreventsthemachinetheaccidentdamage.Suchasthecowling,theguardplateguardsagainstthecollisionstructuraldesign;Movesthearmhydrauliccylinderguardplatedesign;Fueloiltankdraw-offvalve;Theindependencebulldozestheboardhydraulicpressurehosedesign;Waterproofingelectricsystemdesign;Intheworkinstallmenthosesetsatthedesign;Xframeandhalfwayupthemountainsidecaterpillarbanddesign;Theenginemachineoilfilterelementreplacementtimelengthens;Hasforerunnersystemwhichthepipelinefilters;Dualspatiallyfiltersstructuredesignandsoon.5ConclusionsSociety'sdevelopmenthasamoretremendousinfluencetothesmallexcavator,atpresenttheoverseassmallexcavatorhadthesuitabledevelopment,likeCarterotherforces,companyandsoonHitachi,smallpine,Mitsubishi,thesmallexcavatorproducthasformedtheseries,andinunceasinglycarriesonthedevelopment,theexpandeduse,theincreaseappendixtype.Thedomesticsmallexcavatordevelopmenthasalsoobtainedthecertainresult,butallneedsfurthertoimproveandtheconsummationinthetechnologyandtheproduction.-7-國內外小型挖掘機發展綜述一、液壓挖掘機簡介液壓挖掘機是由發動機、液壓系統、工作裝置、行走裝置和電氣控制等部分組成。液壓系統由液壓泵、控制閥、液壓缸、液壓馬達、管路、油箱等組成。電氣控制系統包括監控盤、發動機控制系統、泵控制系統、各類傳感器、電磁閥等。液壓挖掘機一般由輪胎式、步履式、全液壓、半液壓、全回轉、非全回轉、通用型、專用型、鉸接式、伸縮臂式等多種類型。工作裝置是直接完成挖掘任務的裝置。它由動臂、斗桿、鏟斗等三部分鉸接而成。作業的需要，液壓挖掘機可以配裝多種工作裝置，如挖掘、起重、裝載、平整、夾鉗、推土、沖擊錘等多種作業機具。是液壓挖掘機的動力源，大多采用柴油要在方便的場地，也可改用電動機。動工作裝置動作，從而完成各種作業。以工地使用較多的PV-200型液壓挖掘機為例。該機采用改進型的開式中心OLSS斜盤角（輸出流量）的方法，減少了發動機的功率輸出，從而減少燃油消耗，是一種節能型系統。這種液壓系統的特點是：定轉矩控制，能維持液壓泵驅動轉矩不變，載斷控流量，減少功率損失。-8-逐步發展過程。由于液壓技術的應用，20世紀40年代有了在拖拉機上配裝液壓反鏟的懸掛式機械，20世紀50年代初期和中期相繼研制出拖式全回轉液壓挖掘機和履帶式全20世紀60年代起，液壓挖1968-1970年間，液壓挖掘機產量已占機械總產量的83%，目前已接近100%。二、小型挖掘機的發展及其趨勢20世紀80～90年代小型挖掘機在市政工程、交通、管道等施工中發揮了較大優勢并得以迅速發展。它在城市的土建施工工程中為節省人力、物力出了較大貢獻,逐步成為城市施工中具有代表性的施工機械。小型挖掘機的發展主要依賴于城市建設的發展,由于城市的改造、建設施工較多,要求施工時間短、施工機械對周圍環境影響小、安全、低污染、回轉半徑小、便于運輸以及具有與城市景色相協調的外觀,小型挖掘機滿足了城市各種作業要求，在城市狹窄的工作空間內能夠最大限度地發揮其生產能力,因此具有獨特的優越性。1.小型挖掘機的發展小型挖掘機在城市中主要用于土建施工及一般住宅修整等工作,要求具有良好工作性能和回轉性能。最初的小型挖掘機以輪胎式為主,由于輪胎式在軟地面的行走性和通過性差,后來逐漸被履帶式替代,并在動臂支撐機構處增加了回轉機構,使整個工作裝置能相對機體進行左右擺動,以完成溝道側壁挖掘整修工作,但這種小型挖掘機挖掘范圍小、不能實現后部卸料。此后,小型挖掘機增加了上部回轉機構,解決了后部卸料等問題,提高了挖掘機的工作性能,形成小型挖掘機的基本結構。后來,小型挖掘機在回轉半徑、后部視野、動臂仰角、機械性能等方面得到進一步改善,發展為現在的標準型。2.技術的進步小型挖掘機工作環境大部分在城市,為了防止行走時損壞路面,從80年代開始使用橡膠履帶,,鐵芯板接縫處與支重輪接觸落地時,成為行走破壞路面的主要原因。以前使用寬形鐵芯板,橡膠履帶的支重輪直徑較大,因此在接近地面時,這個縫隙變大,-9-掘機使用與以前相同的支重輪,只是履帶內使用的鐵芯板變窄,因此在接觸地面時縫隙變后方小回轉型挖掘機的回轉尾部尺寸非常小,為了確保挖掘機工作的穩定性,必須有足夠的