~.A2!! TheEngineering~ Resource For,..,........ AdvancingMobility 400COMMONWEALTH DRIVEWARRENDALE,PA 15096 rsI '" rl 861290 Development oftheHydraulic Systemforthe Caterpillar 416Backhoe Loader JayJ.Wait Caterpillar Inc, Reprinted fromSP-679­ FluidPowerTechnology andSystems International Off-Highway &Powerplant Congress &Exposition Milwaukee, Wisconsin September 8-11,1986Downloaded from SAE International by North Carolina State Univ, Saturday, September 15, 2018SAEGLOBAL MOBIUTY nATABAS£ Nopartofthispublication maybereproduced inanyform, inanelectronic retrievalsystemorotherwise, withoutthe priorwrittenpermission ofthepublisher. ISSN0148·7191 Copyright 1986SocietyofAutomotive Engineers, Inc. ThispaperissUbjecttorevision.Statements andopinions advanced in papersordiscussion aretheauthor'sandare hisresponsibility, notSAE's;however, thepaperhasbeen editedbySAEforuniformstylingandformal.Discussion willbeprintedwiththepaperif itispublished inSAE Transactions. Forpermission topUblishthispaperinfullor inpart,contacttheSAEPublication Division.AllSAEpaprrsQrtWJtTactrd IJJU1ltUi~.xtd illthtSAEGlobl1.!Mo!:llIty!MrabaJt Persons wishingtosubmitpaperstobeconsidered for presentation orpublication throughSAEshouldsendthe manuscript ora300wordabstract ofaproposed manu­ scriptto:Secretary, Engineering ActivityBoard,SAE. PrintedinU.S.A.Downloaded from SAE International by North Carolina State Univ, Saturday, September 15, 2018861290 Development oftheHydraulic Systemforthe Caterpillar 416Backhoe loader JayJ.Wait Caterpillar Inc. which basic loader backhoeABSfRACT Akeyingredient illthedevelopment ofthe Caterpill ar416backhoe loader wasthe development ofthehydraulic system. Aload sensing, pressure compensated system was selected onthebasisofitsbestbeingableto meetdesigngoals. Theresultisabackhoe loaderinwhichthehydraulic systemcontributes greatly tothevehicle's overall acceptance by operating efficiently andutilizing lowlever effortsforeaseofcontrol. Therecently introduced Caterpillar 416 backhoe loader(fig.1)isasmallutility vehicle intended foruseinawidevariety of applications. Whenthedesignofthisvehicle wasfirstconsidered, anumberofgoalswere identified. Fromstudies ofcompetitive vehicles andinterviews withbackhoe loader FIG.1416BACKHOE LOADER 19operators, lowleverefforts andgoodmultiple tur.ctlon capability wereidentified asthetwo hydraulic systemcharacteristics mostcritically neededforgoodvehicle acceptance. Other factors whichwereexpected toimproveoperdtor acceptance ofthevehicle weresmoothness of operation, goodcontrollability, andauniform swingvelocity. Inaddition, itemssuchaslow heatload(goodefficiency), lowcost,low leakage(gooddriftcontrol), andthecapability toprovide flowforallvehicle hydraulic )~equirements, including steering, were considered desirable forvariousotherreasons. Finally, thesystemhadtoprovide stability, goodresponse, predictable operation, good reliability andserviceability, andother features asnecessary tomeetminimum vehicle performance requirements. Thepurpose ofthis paperistodiscuss howthe416hydraulic system wasdesigned to provide thesefeatures. SYSTENSELECTION Earlyinthevehicledevelopment program, a numberofdifferent typesofhydraulic systems wereevaluated forthe416.Inaddition tothe loadsensing system, opencentersystemswith or.eortwopumps,andahighpressure star.dby systemwereconsidered. Pilotactuation was alsoconsidered becauseofitscapability for providing alowlevereffort. Allofthese systems werecompared onthebasisofcost, function, andtheabilityto provide thedesired features. Sincetheloadsensing system ,"epresented arelatively newtechnology, atest bedvehicle wasbuilttoaidintheevaluation oftheloadsensing system. Othertypesof systemswereevaluated onthebasisoftheir known operating characteristics andby observation oftheiroperation oncompetitive vehicles. Onemajorvehicle characteristic influenced thesystemselection wasthe difference between thebackhoe and systemsofabackhoeloader. WhiletheDownloaded from SAE International by N