>> P.456
2LifeofMaintenance-freesphericalbushings[1]ConfirmationofpVvalueBeforeattemptingtocalculatethelife,makesurethattheoperatingconditionsarewithinthepermissiblerangebyreferringtothepVdiagraminFig.4.Whentheoperatingconditionsareoutofthepermis-siblerange,pleaseconsultIKO.ThecontactpressurepandtheslidingvelocityVareobtainedfromequations(3)and(4)shownonpageK6.[2]LifecalculationThelifeofmaintenance-freesphericalbushingsisobtainedfromthetotalslidingdistanceSwhichisgiveninFig.5forthecontactpressurepobtainedfromequation(3).Thetotalnumberofoscillationsandlifeinhourscanbeobtainedfromthefollowingequations. G=16.67×b1…………………………(7) Sf V G 60f……………………………………(8)Lh=where,G:Life(Totalnumberofoscillations)b1:Loaddirectionalfactor(RefertoTable14.)S:Totalslidingdistancem(RefertoFig.5.) f:Numberofoscillationsperminutemin-1V:Slidingvelocitymm/s Lh:LifeinhourshWhenalternateloadsareapplied,thisrangeisalsopermissible.Permissiblerange1006040201068421N/mm2pContactpressure124610204060100200SlidingvelocityVmm/sFig.4pVdiagramofMaintenance-freesphericalbushingsTable14Loaddirectionalfactorb1(Maintenance-free)Thelifeofsteel-on-steelsphericalbushingscanbecalculatedfromthefollowingequations. 3.18b1b2b3 Cdt×105 ……………(5)G=()2 dkβ P60f G ……………………………………(6)Lh=where, G:Life(Totalnumberofoscillations) b1:Loaddirectionalfactor(RefertoTable12.) b2:Lubricationfactor(RefertoTable13.)b3:Slidingvelocityfactor(RefertoFig.3.)Cdt:DynamicloadcapacityconsideringtemperatureincreaseN(Refertoequation(1).) P:EquivalentradialloadNLh:Lifeinhoursh f:Numberofoscillationsperminutemin-1(Refertoequation(2).)Table12Loaddirectionalfactorb1(Steel-on-steel)LoaddirectionConstantAlternateLoaddirectionalfactorb115Table13Lubricationfactorb2PeriodicallubricationNoneRegularLubricationfactorb21150.20.515Slidingvelocity10Vmm/s50100150Loaddirection:AlternateLoaddirection:Constant234510.50.40.30.20.10.050.040.030.020.01b3Slidingvelocityfactor[2]LifecalculationFig.3SlidingvelocityfactorLoaddirectionConstantAlternateLoaddirectionalfactorb110.2(1)Note(1) Thisvalueisapplicablewhenloadchangescom-parativelyslowly.Whentheloadchangesrapidly,pleaseconsultIKO,asthefactordegreasessharply.theK7
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