Bearing tolerances

The tolerances for the dimensions and running accuracy of bearings are set out in ISO 492/199/582. This largely corresponds to DIN 620.

Accuracy of rolling bearings

Tolerances for dimensions: items necessary to mount bearings on shafts or in housings

  • Tolerances for bore and outside diameters, ring and bearing width
  • Tolerances for inscribed and circumscribed circle diameters of rollers
  • Tolerances for chamfer dimensions
  • Tolerances for width variation
  • Tolerances for tapered bore diameters

Running accuracy: items necessary to specify the run-out of rotating machine parts

  • Permissible radial run-out of inner and outer rings
  • Permissible face run-out with raceway inner and outer rings
  • Permissible inner ring face run-out with bore
  • Permissible outer ring variation of outside surface generatrix inclination with face
  • Permissible raceway-to-back-face thickness variation of thrust bearings

Accuracy classes of rolling bearings

Apart from the standard accuracies defined by DIN/ISO, higher accuracies are specified by 6x, 6, 5, 4 and 2.

Bearing types and tolerance classes
Bearing types Applicable tolerance classes
Deep groove ball bearings Normal Class 6 Class 5 Class 4 Class 2
Angular contact ball bearings Normal Class 6 Class 5 Class 4 Class 2
Self-aligning ball bearings Normal Class 6 Class 5 - -
Cylindrical roller bearings Normal Class 6 Class 5 Class 4 Class 2
Needle roller bearings (solid type) Normal Class 6 Class 5 Class 4 -
Spherical roller bearings Normal Class 6 Class 5 - -
Tapered roller earings Metric design Normal Class
6X
- Class 5 Class 4 -
Inch design ANSI/ABMA
Class 4
ANSI/ABMA
Class 2
ANSI/ABMA
Class 3
ANSI/ABMA
Class 0
ANSI/ABMA
Class 00
Magneto bearings Normal Class 6 Class 5 - -
Thrust ball bearings Normal Class 6 Class 5 Class 4 -
bearings Normal - - - -
Equivalent standards
(reference)
JIS(1) Class 0 Class 6 Class 5 Class 4 Class 2
DIN(2) P0 P6 P5 P4 P2
ANSI/ ABMA(3) Ball bearing ABEC 1 ABEC 3 ABEC 5
(Class 5P)
ABEC 7
(Class 7P)
ABEC 9
(Class 9P)
Roller bearing RBEC 1 RBEC 3 RBEC 5 - -
Tapered roller bearing Class 4 Class 2 Class 3 Class 0 Class 00

Notes:
(1) JIS: Japanese Industrial Standards
(2) DIN: Deutsche Industrie Norm
(3) ANSI/ABMA: The American Bearing Manufacturers Association

The tolerances of the accuracy class “Normal” (P0) are sufficient for general applications in most cases.

Typical tolerance classes for specific applications (reference)
Bearing requirement, operating conditions Examples of applications Tolerance classes
High running accuracy is required VTR drum spindles
Magnetic disk spindles for computers
Machine tool main spindles
Rotary printing presses
Rotary tables of vertical presses, etc.
Roll necks of cold rolling mill backup rolls
Slewing bearings for parabolic antennae
P5
P5, P4, P2
P5, P4, P2
P5
P5, P4
Higher than P4
Higher than P4
Very high speed is required Dental drills
Gyroscopes
High-frequency spindles superchargers
Compresors
Centrifugal separators
Main shafts for jet engines
Class 7P, Class 5P
Class 7P, P4
Class 7P, P4
P5, P4
P5, P4 Higher than P4
Low torque and low torque variation are required Gyroscope gimbals
Servomechanisms
Potentiometric controllers
Class 7P, P4
Class 7P, Class 5P
Class 7P

Measuring methods

bearing tolerance measuring methods

Running accuracy Inner ring Outer ring Measuring point
Kia rotating stationary A
Kea stationary rotating A
Sia rotating stationary B1
Sea stationary rotating B2
Sd rotating stationary C
SD - rotating D
Si , Se Only the shaft or housing or central washer is to be rotated E

Chamfer dimension of inner/outer ring
r: Chamfer dimension of inner/outer ring
r1: Chamfer dimension of inner/outer ring (front side) or the centre washer of thrust ball bearings

Remarks: The exact shape of the edge reduction results from the radius that is reduced in the area of the face and rolling surfaces. Make sure that there is no contact between the surrounding structure and the bearing in the area of the edge reduction. The radius here is smaller than the r (min) or r1 (min) value quoted in the bearing table. (According to DIN 616, ISO 15 and ISO 355.)

Tolerances for tapered bores (Class Normal)

bearing tolerance for tapered bores (Class Normal)

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