>> P.199
PrecautionforUse❶FittingBGseriesisgenerallyusedwithaslightradialinternalclearancefit.RecommendedfitsareshowninTable2.Whenitisusedforaguidepostofthepressdiesetorhighoperationaccuracyisrequired,apreloadisgenerallygiven.ThetolerancesofdimensionsoftheshaftandhousingboreinthiscaseareshowninTable3.However,sinceexcessivepreloadshortenstheissuggestedthatthelowerlimitofradialclearanceisnotsmallerthanthevalueshowninTable4.lifeofStrokeRotaryCage,itTable2GeneralfitToleranceclassShafth5,h6HousingholeH6,H7Table3Tolerancesofdimensionsforshaftandhousingunit:μmhole❷RacewayBGseriesisusedwithashaftandhousingholeasracewaysurfaces.RecommendedvaluesforsurfacehardnessandroughnessofmatingracewayareshowninTable5andtherecommendedvaluesfortheminimumeffectivehardeningdepthareshowninTable6.Whensomeoftheballsheldintheretainerescapethehousingisrecommendedthatthehousingracewayendsshouldbeslightlychamferedsothattheballsenterorexitsmoothly.racewayandoperateinlinearmotion,itTable5SurfacehardnessandroughnessofracewayItemRecommendedvalueRemark58～64HRCSurfacehardnessSurfaceroughnessWhenthesurfacehardnessislow,multiplytheloadratingbyhardnessfactor(1).Whereaccuracystandardislow,around0.8μmRa(3.2μmRy)isalsoallowed.0.2μmRaorlower(0.8μmRyorlower)Nominaldimensionsmm192225283238Shafth5H000000HousingholeNote(1)Forhardnessfactor,refertoFig.3inpageⅢ-5.Nominaldimensionsmm252831364048K5H+1+1+2+2+2+2L-8-8-9-9-9-9L-9-9-9-9-11-11Table6Minimumeffectivehardeningdepthofracewayunit:mmNominaldimensionsofshaftandhousingholeRecommendedvalueforminimumeffectivehardeningOver-28Incl.2850depth0.81.0Table4Lowerlimitofradialinternalclearanceunit:μmNominaldimensionsofshaftLowerlimitofradialinternalmm192225283238clearance-5-5-5-7-7-7Ⅱ-191
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