Ball and Roller Bearings

Bearing Tolerances6. Bearing Tolerances6.1 Dimensional accuracy and running accuracyBearing “tolerances” or dimensional accuracy andrunning accuracy, are regulated by ISO and JIS B 1514standards (rolling bearing tolerances). For dimensionalaccuracy, these standards prescribe the tolerancesnecessary when installing bearings on shafts or inhousings. Running accuracy is defined as the allowablelimits for bearing runout during operation.Dimensional accuracyDimensional accuracy constitutes the acceptable valuesfor bore diameter, outer diameter, assembled bearingwidth, and bore diameter uniformity as seen in chamferdimensions, allowable inner ring tapered bore deviationand shape error. Also included are, average bore diametervariation, outer diameter variation, average outer diameterunevenness, as well as raceway width and height variation(for thrust bearings).Running accuracyRunning accuracy constitutes the acceptable values forinner and outer ring radial runout and axial runout, innerring side runout, and outer ring outer diameter runout.Allowable rolling bearing tolerances have beenestablished according to precision classes. Bearingprecision is stipulated as JIS class 6, class 5, class 4, orclass 2, with precision rising from ordinary precisionindicated by class 0.Table 6.1 indicates which standards and precisionclasses are applicable to the major bearing types. Table6.2 shows a relative comparison between JIS B 1514precision class standards and other standards. For greaterdetail on allowable limitations and values, refer to Tables6.3 - 6.8. Allowable values for chamfer dimensions areshown in Table 6.9, and allowable limitations and valuesfor radial bearing inner ring tapered bores are shown inTable 6.10.Table 6.1 Bearing types and applicable toleranceBearing typeDeep groove ball bearingsAngular contact ball bearingsSelf-aligning ball bearingsCylindrical roller bearignsNeedle roller bearingsSpherical roller bearingsTaperedrollerbearingsmetricInchThrust ball bearingsJ seriesSpherical roller thrust bearingsApplicable standard Tolerance class Tolerance tableJIS B 1514(ISO492)JIS B 1514ANSI/ABMA Std.19ANSI/ABMA Std.19.1JIS B 1514(ISO199)class 0class 0class 0class 0class 0class 0class 06Xclass 4class Kclass 0class 0class 6class 6class 6class 6class 6class 2class Nclass 5class 5class 5class 5class 3class Cclass 6 class 5class 5 class 4class 4class 4class 4class 4class 0class Bclass 4class 2class 2class 2class 00class A Table 6.3Table 6.4Table 6.5Table 6.6Table 6.7Table 6.8Table 6.2 Comparison of tolerance classifications of national standardsStandardJapanese industrialstandard (JIS)International Organizationfor Standardization (ISO)Deutsches Institutfur Normung(DIN)American NationalStandards Institute (ANSI)American BearingManufacturer's Association(ABMA)Applicable standerdJIS B 1514ISO 492ISO 199ISO 578ISO 1224DIN 620ANSI/ABMA Std.20ANSI/ABMA Std.19.1ANSI/ABMA Std.19Tolerance ClassClass 0,6X Class 6 Class 5 Class 4 Class 2NormalclassClass 6XNormalClassClass 4P0ABEC-1RBEC-1Class KClass 4Class 6Class 6Class NClass 2Class 5 Class 4 Class 2Class 5 Class 4Class 3 Class 0 Class 00 Class 5A Class 4A P6 P5 P4 P2ABEC-3RBEC-3ABEC-5RBEC-5 ABEC-7Class C Class BABEC-9Class AClass 3 Class 0 Class 001 "ABEC" is applied for ball bearings and "RBEC" for roller bearings.Notes 1: JIS B 1514, ISO 492 and 199, and DIN 620 have the same specification level.2: The tolerance and allowance of JIS B 1514 are a little different from those of ABMA standards.1All typeBearing TypesRadial bearingsThrust ball bearingsTapered roller bearings (Inch series)Precision instrument bearingsAll typeRadial bearings(Except tapered roller bearings)Tapered roller bearings (Metric series)Tapered roller bearings (Inch series)A-35