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8. BEARING TOLERANCES

8.1 Bearing Tolerance Standards Regarding bearing accuracy classes, besides ISO (Reference) Rough definitions of the items listed for Supplementary Table
normal accuracy, as the accuracy improves there Running Accuracy and their measuring methods are
The tolerances for the boundary dimensions and are Class 6X (for tapered roller bearings), Class 6, shown in Fig. 8.1, and they are described in detail in Running Inner Outer Dial
running accuracy of rolling bearings are specified by Class 5, Class 4, and Class 2, with Class 2 being the ISO 5593 (Rolling Bearings-Vocabulary) and JIS B Accuracy Ring Ring Gauge
ISO 492/199/582 (Accuracies of Rolling Bearings). highest in ISO. The applicable accuracy classes for 1515 (Rolling Bearings-Tolerances) and elsewhere.
Tolerances are specified for the following items: each bearing type and the correspondence of these K ia Rotating Stationary A
classes are shown in Table 8.1. A
K ea Stationary Rotating B1
B2
Sia Rotating Stationary C
D
⋅ Tolerances for bore and outside diameters, ring width Sea Stationary Rotating
and bearing width E
( )Tolerances for Dimensions Measuring B2 A Sd Rotating Stationary
Items necessary to mount ⋅ Tolerances for inscribed and circumscribed circle Weight A C
bearings on shafts or in diameters of rollers SD ⎯ Rotating
housings Si , Se
⋅ Tolerances for chamfer dimensions Only the shaft or housing
( )Running Accuracy ⋅ Tolerances for width variation or central washer is to be
Items necessary to ⋅ Tolerances for tapered bore diameters rotated.
specify the runout of
Accuracy of Rolling Bearings rotating machine parts ⋅ Permissible radial runout of inner and outer rings
⋅ Permissible face runout with raceway inner and outer
C
rings
⋅ Permissible inner ring face runout with bore E
⋅ Permissible outer ring variation of outside surface
B1 Measuring D r (max.)×1.2
generatrix inclination with face Weight
⋅ Permissible raceway to back face thickness variation of

thrust bearings

Table 8. 1 Bearing Types and Tolerance Classes

Bearing Types Applicable Tolerance Classes Applicable Reference r (max.)×1.2 Supporting pins
Tables Pages Stops (at two points) Stops at two points for at three points around
inside or outside surface circumference

Deep Groove Ball Bearings Normal Class 6 Class 5 Class 4 Class 2 Fig. 8.1 Measuring Methods for Running Accuracy (summarized)

Angular Contact Ball Bearings Normal Class 6 Class 5 Class 4 Class 2
Normal Class 6 Class 5 ⎯ ⎯
Normal equivalent equivalent Symbols for Boundary Dimensions and Running Accuracy
Class 6 Class 5 Class 4 Class 2
Self-Aligning Ball Bearings Table A60 d Brg bore dia., nominal D Brg outside dia., nominal
8.2 to A63 &ds Deviation of a single bore dia. &Ds Deviation of a single outside dia.
Cylindrical Roller Bearings &dmp Single plane mean bore dia. deviation &Dmp Single plane mean outside dia. Deviation
Table A64 Vdp Bore dia. Variation in a single radial plane VDp Outside dia. Variation in a single radial
Needle Roller Bearings Normal Class 6 Class 5 Class 4 ⎯ 8.3 to A67 Vdmp Mean bore dia. Variation
(solid type) Table A68 plane
Spherical Roller Bearings Normal Class 6 Class 5 ⎯ ⎯ 8.4 and A69 B Inner ring width, nominal VDmp Mean outside dia. Variation
Table A70 &Bs Deviation of a single inner ring width
Tapered Metric Normal ⎯ Class 5 Class 4 ⎯ 8.5 and A71 VBs Inner ring width variation C Outer ring width, nominal
Roller Design Class 6X Table A72 &Cs Deviation of a single outer ring width
Bearings Inch Design 8.4 to A74 Kia Radial runout of assembles brg inner ring VCs Outer ring width variation
ANSI/ABMA ANSI/ABMA ANSI/ABMA ANSI/ABMA ANSI/ABMA Table A75 Sd inner ring reference face (backface, where
CLASS 4 CLASS 2 CLASS 3 CLASS 0 CLASS 00 8.7 Kea Radial runout of assembled brg outer ring
⎯ ⎯ applicable) runout with bore SD Variation of brg outside surface generatrix
Magneto Bearings Normal Class 6 Class 5 ⎯ ⎯ Sia Assembled brg inner ring face (back face)
inclination with outer ring reference face
Thrust Ball Bearings Normal Class 6 Class 5 Class 4 ⎯ runout with raceway (backface)
Si, Se Raceway to backface thickness variation Sea Assembled brg outer ring face (backface)
Thrust Spherical Roller Bearings Normal ⎯ ⎯ ⎯ ⎯ runout with raceway
of thrust brg
JIS(1) Class 0 Class 6 Class 5 Class 4 Class 2

Equivalent standards DIN(2) P0 P6 P5 P4 P2 ⎯ ⎯
(Reference)
Ball ABEC 1 ABEC 3 ABEC 5 ABEC 7 ABEC 9 Table A60 T Brg width, nominal CT
Bearings RBEC 1 RBEC 3 (CLASS 5P) (CLASS 7P) (CLASS 9P) 8.2 to A63 &Ts Deviation of the actual brg width
ANSI/ CLASS 4 CLASS 2 (A76
ABMA(3) Roller RBEC 5 ⎯ ⎯ [ ]Table and A77)
Bearings CLASS 3 CLASS 0 CLASS 00 8.8 (A68
Tapered Roller and A69)
Bearings [ ]Table
8.4
B
Notes (1) JIS : Japanese Industrial Standards (2) DIN : Deutsch Industrie Norm jd jD
(3) ANSI/ABMA : The American Bearing Manufacturers Association

Remarks The permissible limit of chamfer dimensions shall conform to Table 8.9 (Page A78), and the tolerances and permissible
tapered bore diameters shall conform to Table 8.10 (Page A80).

A 58 A 59