SKF - Rolling Bearings

Bearing specifics
Dimensions
For information about main dimensions of a
bearing, refer to Boundary dimensions
(† page 40).
Chamfer dimensions
Minimum values for the chamfer dimensions
(† fig. 1) in the radial direction (r 1 , r 3 ) and the
axial direction (r 2 , r 4 ) are listed in the product
tables. These values are in accordance with
the general plans listed in the following
standards:
• ISO 15, ISO 12043 and ISO 12044 for radial
rolling bearings
• ISO 355 for radial tapered roller bearings
• ISO 104 for thrust rolling bearings
The appropriate maximum chamfer limits that
are important when dimensioning fillet radii
are in accordance with ISO 582 († Tolerances).
Tolerances
The dimensional and running accuracy of rolling
bearings has been standardized internationally.
In addition to the Normal tolerances, the ISO
standards also cover closer tolerances, such as:
• tolerance class 6, which corresponds to
SKF P6 tolerance class
• tolerance class 5, which corresponds to
SKF P5 tolerance class
For special applications like machine tool
spindles, SKF also manufactures bearings
with higher accuracy. These include the P4,
P4A, PA9A, SP and UP tolerance classes.
For add itional information, refer to Superprecision
bearings († skf.com/super-precision).
For tolerance information about each bearing
type, refer to Tolerances in the relevant
product chapter. Bearings with higher accuracy
than Normal are typically identified by a
designation suffix for the tolerance class.
Tolerance symbols
The tolerance symbols and their definitions
are provided in table 1 († page 134).
Fig. 1
Diameter series identification
The bore and outside diameter variation tolerances
V dp and V Dp for metric rolling bearings
(† tables 3 to 5, pages 137 to 139 – except
tapered roller bearings) are not universally
valid for all diameter series. To determine the
diameter series of a radial bearing, refer to
table 2 († page 136).
r 1 , r 3
r 2 , r 4
132