>> P.314
Ⅲ-20Preload1N=0.102kgf=0.2248lbs.1mm=0.03937inchObjectivesofpreloadInsomecases,thelinearmotionrollingguideisusedwithclearancegiventothelinearmotionrollingguidewhenlightmotionwithsmallloadisrequired.However,forsomeapplications,itmaybeusedwithplayintheguidingmechanismremovedorwithpreloadtoincreaserigidity.Preloadisappliedtothecontactpartsofaracewayandrollingelementswithinternalstressgeneratedinadvance.Whenaexternalloadisappliedonthepreloadedlinearmotionrollingguide,shockabsorbingwiththisinternalstressmakeselasticdeformationsmaller,anditsrigidityisincreased.(SeeFig.3)PreloadsettingPreloadamountisdeterminedbyconsideringthecharacteristicsofthemachinesorequipmentsonwhichthelinearmotionrollingguideismountedandthenatureofloadactingonthelinearmotionrollingguide.Thestandardamountofpreloadforlinearmotionrollingguidesis,ingeneral,approx.1/3ofloadwhentherollingelementsareballs(steelballs)andapprox.1/2ofloadwhentheyarerollers(cylindricalrollers).Ifthelinearmotionrollingguidesarerequiredtohaveveryhighrigiditytowithstandvibrationorfluctuatingload,alargerpreloadmaybeapplied.Forapplicablepreloadamount,seeTable9.Fordetails,seeanexplanationofeachseries.PrecautionforpreloadselectionEvenwhenhighrigiditymustberequired,excessivepreloadshouldbeavoided,becauseitwillproduceanexcessivestressbetweenrollingelementsandraceways,andeventuallyresultinshortlifeoflinearmotionrollingguides.Itisimportanttoapplyaproperamountofpreload,consideringtheoperationalconditions.Whenusingwithalargepreload,contactIKO.Ball(withoutpreload)Roller(withoutpreload)Roller(withpreload)Ball(withpreload)201510500100020003000LoadNElasticdeformationmBalldiameter10mmPreloadamount:Equivalentto0.05×C0Diameterandlengthofroller10mm×10mmFig.3PreloadandelasticdeformationbehaviorTable9SeriesandpreloadamountPreload(preloadsymbol)SeriesnameClearanceClearanceStandardLightpreloadMediumpreloadHeavypreload(TC)(T0)(Nosymbol)(T1)(T2)(T3)C-LubeLinearWayMLLinearWayL-○○○--C-LubeLinearWayMLV(1)------C-LubeLinearWayMV○-○○--C-LubeLinearWayMELinearWayE○-○○○-C-LubeLinearWayMHLinearWayH-○○○○○LinearWayF--○○○-C-LubeLinearWayMULLinearWayU--○○--C-LubeLinearRollerWaySuperMXLinearRollerWaySuperX--○○○○LinearRollerWayX--○○○○Note(1)Preloadisadjustedtohavesubtleclearanceorminimalamountofpreload.
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