汽车起重机大学论文外文翻译Word格式.docx
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汽车起重机大学论文外文翻译Word格式.docx
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外文翻译
译文题目:
使用智能液压缸增加起重机的稳定性
学院:
机电学院
专 业:
机械设计制造及其自动化
学生姓名:
XXX
学 号:
1234567890
指导教师:
XXX
完成时间:
2017年3月12日
From:
Hitchcox,Alan. Smartcylinders stabilizecranes[J].Hydraulics &
Pneumatics;
Cleveland(Sep 12,2013):
n/a.
Smartcylinders stabilizecranes
Hitchcox,Alan.
ASMInternational,PentonMedia,OTPIndustrialSolutions
(formerlyOhioTransmission&
PumpCo)
Abstract:
It'
s notunusual forcranestoreach 100ftormoreintothe air atmajorconstructionsites.Traditionally, cranes aretransported toaworkareaand assembled on-site. Morerecently,as truck-mountedcranesbecomebigger andmorepowerful,they havefoundfavor because they arequickerto setup thantraditionalcranes.Truck-mountedcraneshave a telescopinghydraulicboommountedoncommercialtruck chassis. Theirportabilityandlower setupcostshave ledtotheirwidespread useatconstruction andutilitysitesaround theworld.But asloadsgetheavier andliftingdistancesbecomehigher,designersoftruck-mountedcranes must providethestabilitytoensurethatsafetyremains thetoppriority.
Truck-mounted cranesuseoutriggersystems toensurestableoperation.Theoutriggers extend from themainbodyofthetruckandcontactthegroundseveralfeet awayfromthetruck. This distributesthecrane'sloadoveramuchlargerarea,thereby increasingstability.Manitowoc CompanyInc., Manitowoc, Wis.,takesthisastep furtherbyusingsmartcylindersinthe A-frameoutriggersystemsofitsNationalCraneline of truck-mountedcranes.Thecrane'
shydraulicsystem isdrivenfrom apowertakeoff onthe truck'stransmission. The craneoperatorthen runsallcranefunctions throughaseries of lever-operated valvesat acontrolstation.
TheELAisanexternallymountedLDTthatuses Hall-effect technologyto sensethelocation ofa magnet embeddedinthecylinder's piston through thecylinder'
scarbonsteelbarrel.Amicroprocessorthen assignsananalog voltageto the magnet'
scorrespondingabsoluteposition.For example,whenthe cylinderisfully retracted;
the voltagemaybe0.55V.Asthecylinder extends,the voltagegraduallyincreasesuntil4.5 Vis reachedatfullextension. Accuracyof thetransduceris typically+-0.5mm(0.02in.)-more thanadequateformostmobileequipment. Thatpositionis thensentto theECMandcomparedtotheknownmaximumhorizontalextension. Afterthis,anindicationisgiventotheoperatorabouttheoutrigger state.Thepositionupdate happens within milliseconds.
FullText
It'
s notunusual forcranestoreach100ftormoreinto theairat majorconstructionsites.Traditionally,cranesaretransportedtoaworkareaandassembledon-site. Morerecently,as truck-mountedcranesbecomebiggerandmore powerful, theyhavefoundfavorbecause theyarequickertosetupthantraditionalcranes. Truck-mountedcraneshave atelescoping hydraulicboommounted oncommercialtruckchassis.Theirportabilityandlowersetupcosts haveledtotheirwidespreaduse atconstructionand utilitysitesaroundtheworld.Butasloadsget heavier andliftingdistances becomehigher,designers oftruck-mountedcranesmust provide thestabilitytoensurethatsafety remainsthetoppriority.
Truck-mountedcranesuseoutriggersystemstoensurestableoperation. Theoutriggersextend fromthemainbodyof the truckandcontactthe groundseveralfeet awayfromthe truck. Thisdistributes thecrane'sloadovera muchlargerarea, therebyincreasingstability.Manitowoc CompanyInc., Manitowoc,Wis.,takesthisastepfurther byusingsmartcylindersintheA-frameoutriggersystemsof itsNational Cranelineoftruck-mountedcranes. Thecrane'
shydraulic systemisdrivenfromapowertakeoff onthetruck'
stransmission.Thecraneoperatorthen runsall cranefunctionsthroughaseries of lever-operatedvalves atacontrol station.
Animportantfunctionforlifting, moving, and loweringheavyloadsis toensurethatoutriggerbeams areproperlypositioned.Theoutriggers areattachedtothetruckframeand areextendeddownwardbyhydraulic cylindersatanangletocreateanA-framestructurethat iswideratitsbasethan atthetop. Thisprovidesastableframeworktolevelandsupporttheloadedandextendedcrane.
Addingsmartsto outriggers
Forthepastseveral years,NationalCranehasaddedoutrigger-monitoringsystems(OMSs)toitscranes.WiththeOMS,operatorsmonitor the horizontalextensionofthecrane'
soutriggersatacontrolstation. TheOMSused with A-framemodelcranesincludesanELAposition-sensinglinear-displacement transducer(LDT) fromRotaEngineering,Dallas,anelectroniccontrol module(ECM),andbicolor indicationLEDsateachstation.
TheELAisanexternally mountedLDTthatusesHall-effecttechnologytosense thelocation ofamagnetembeddedinthecylinder'
spistonthroughthecylinder's carbonsteelbarrel.Amicroprocessor thenassigns ananalogvoltagetothemagnet'
scorrespondingabsolute position. Forexample,when the cylinderis fully retracted;
the voltage maybe0.55V. Asthecylinderextends,thevoltagegraduallyincreases until4.5V is reachedatfull extension.Accuracy ofthetransducer istypically +-0.5mm(0.02 in.)-morethan adequate formostmobileequipment. Thatpositionis thensenttotheECMandcompared totheknownmaximumhorizontal extension.After this,anindicationisgiventotheoperatoraboutthe outriggerstate.Thepositionupdate happenswithinmilliseconds.
MarkHoffman, ofRota Engineering, pointedoutthatbecausemobileequipment hasahuman operator,positionfeedback fromcylindersgenerallyonlyneedstobe withinhundredthsof aninch. Putsimply,he saysthatmagnetostrictiveLDTsareoverkill formost mobile-equipment applications.He suggests thatan LDTwithslightly less precision,butsubstantiallylowercost,would enable designerstoprovidecylinder position feedbackmoreoften- notjustforthemostcriticalapplicationsthatjustify highcost.
Simpleelectronic display
The electroniccontrolmoduleontheA-frame units servesonlyto monitor thepositionofthe outriggersandprovidefeedbacktothe operator.As theanalogvoltagefromthe ELA transducerisreadintotheECM, it sendsasignaltoa setofbicolorLEDs-oneset peroperator'
sstation.The indicationsavailableare:
Red forsystemerror (sensor out ofrange,electrical short,etc.).
Blinkingredto indicatetheoperatoris notata validworking positionasdirectedby theoperation manual.
Greentoinformtheoperatorthatfullhorizontalextensionhas beenaccomplished.TheECMcanbeconfiguredthroughtheuseofa servicetooltoalso help diagnoseanyissuesrelatedtotheOMS.
Madefor mobile
Designedfor usewithmobile equipment,the ELAtransducer matches thisapplicationwellbecause of severalphysicalandintrinsicattributes.Themost importantoftheseisthe ability tomountthe sensor alongtheexteriorofthehydraulic outrigger-cylinderbarrel.Althoughthe cylindergainsaddedfunctionality,in manycasesitretainsthesameformandfitastheoriginalcylinder;
the smartcylinder isessentiallya drop-inreplacement.Theenvelope inwhichthecylinderis mounteddoes notchange.OnlyadditionalharnessingandtheECMareadded-plus thereareminorphysicalchangestotherearstabilizers.
Thecylinder boresusedinA-frameoutriggersrangefrom3to 4.5 in.Strokes maybeaslongas of66.9in.,dependingon liftingcapacity.According to Hoffman added,"
Eliminatingtheexpenseof gun-drilling thepiston rodand machiningtheendcapreducesthecostof creating thissmart cylinder.The cylinder'
sstructuralintegrityremainsthesame,andit iseasier toassemble,install, and servicethancylinders withmagnetostrictivesensors."
Other positiveattributes:
theHall-effect sensorisnoncontactfor longservicelife,its temperatureratingishigh,itperforms wellinhighshock andvibrationapplications,anditsaluminumhousing resistsdamagefromimpactandcorrosion.Theexternaltransducercanbereplacedin thefieldwithout difficulty.
Cylinderscan besuppliedwithmagnetsalready fitted,sothatifthestroke-sensingfunction isrequiredlater,the transducer caneasilybeadded.Themagnetassembly forthe EL transducerisdesignedto matchthe bore ofthecylinder. Aslotismilledintothepiston toaccommodatethe magnetassembly.Service life isnotafactor becausethemagnetassemblyis madeofthesame qualityas piston-wear rings.
Adifferentkindoflinearsensor
ModelELA linear-displacementtransducers(LDTs) useHall-effect technologyand mountexternallyto mobilehydraulic cylinders. Unlikeothertypesofin-cylinderLDTs,they canbeusedindouble-endedcylinders.They can alsobeusedeffectivelyinsteering andlong-strokecylinders,wheregundrillingcanbecomecost prohibitiveandareeasily fieldreplaceable.
Hall-effect LDTscanbemanufacturedforstrokesexceeding50ftandforuse20,000 ft belowthesurface oftheoceanand otherdemanding environments.
Hall-effecttechnology
LDTs fromRotaEngineeringuseamicroprocessorthattransmitsandreceives signalsfromHall-effect chipsmountedto a printed-circuit board.Thecircuitboardiscontainedwithinastainless-steel oraluminum housing,depending onapplicationrequirements. Apiston-mounted magnetcauses avoltage dropwhen itpassesover theHall-effectchip.Themicroprocessorcalculatestheposition ofthe Hall-effectchip andcorrelatesthe voltagedroptoaproportional voltage,current,PWM,orCANbusoutput.
Hoffmanexplains,"
Hall-effectsensors donot
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