Rolling Bearings Classifications
Rolling bearing construction
Most rolling bearings consist of rings with raceway (inner ring and outer ring), rolling elements (either balls or
rollers) and cage. The cage separates the rolling elements at regular intervals, holds them in place within the
inner and outer raceways, and allows them to rotate freely.
Classification of rolling bearings
Rolling bearings divide into two main classifications: ball bearings and roller bearings. Ball bearings are classified
according to their bearing ring configurations: deep groove type and angular contact type. Roller bearings on
the other hand are classified according to the shape of the rollers: cylindrical, needle, tapered and spherical.
Rolling bearings can be further classified according to the direction in which the load is applied; radial bearings
carry radial loads and thrust bearings carry axial loads.
Other classifications
1) Number of rolling rows (single, double, or 4-row),
2) Separable and non-separable, in which either the inner ring or the outer ring can be detached.
3) There are also bearings designed for special purposes, such as Automotive and other applications
Deep groove ball bearings
The most common type of bearing, deep groove ball bearings are widely used in
a variety of fields. Deep groove ball bearings include shield bearings and sealed
bearings with grease enabling easier usage. Deep groove ball bearings also
include bearings with a locating snap-ring to facilitate positioning when mounting
the outer ring. These type of bearings supports radial load on both directions. Deep
groove ball bearings are also classified into Thin series, Light series, Medium
series and Heavy series ball bearings.
Angular contact ball bearings
Angular contact ball bearings unite point of contact of the inner ring, ball and the
outer ring runs at a certain angle (contact angle) in the radial direction. Bearings
are generally designed with three contact angles. Angular contact ball bearings
can support an axial load, but cannot be used as single bearing because of the
contact angle. They must instead be used in pairs or in combinations. Angular
contact ball bearings include double row angular contact ball bearings for which
the inner and outer rings are combined as a single unit. The contact angle of
double row angular contact ball bearings is 25°. These type support certain
amount of combined loads.
Cylindrical roller bearings
Cylindrical roller bearings use rollers for rolling elements, and therefore has a
high load capacity. The rollers are guided by the ribs of the inner or outer ring.
The inner and outer rings can be separated to facilitate assembly, and both can
be fitted with shaft or housing tightly. If there are no ribs, either the inner or the
outer ring can move freely in the axial direction. Cylindrical roller bearings are of
different types, like N, NU, NJ, NUP, NF depending upon the construction of inner
and outer rings. Cylindrical roller bearings are designed with multiple row rollers
and full compliment rollers without cage depending on the applications. These
bearings are suitable for heavy radial and impact loading and are appropriate for
high speed applications.
3
Rolling Bearings Classifications
Tapered roller bearings
Tapper roller bearings are designed such that the outer ring, inner ring and the
rollers have tapered surfaces whose apexes converge at a common point on the
bearing axis. Tapper rollers are available in metric as well as inch dimensions most
commonly called as metric series and inch series . Tapper rollers are available in
Single, Double and four row, these type of bearings are suitable for Heavy and
Impact load application and can take both radial and axial load simultaneously.
Spherical roller bearings
Spherical roller bearings are equipped with an outer ring with a spherical raceway
surface and an inner ring which holds two rows of barrel shaped rolling elements,
spherical roller bearings are able to adjust center alignment to handle inclination
of the axle or shaft. There are varieties of bearing types that differ according
to internal design. Spherical roller bearings include as type equipped with an
inner ring with a tapered bore. The bearing can easily be mounted on a shaft by
means of an adapter or withdrawal sleeve. The bearing is capable of supporting
heavy loads, and is therefore often used in industrial machinery. Gages for these
bearings are of both steel and brass depending on the applications.
Thrust bearings
Thrust bearings are classified in accordance to
the rolling elements they contain and generally the
allowable rotational speed is very low.
Thrust ball bearing with single row is called as single
direction Thrust ball bearings and can take axial load
in one direction, whereas Thrust ball bearing with
double row is called as double direction Thrust ball
bearings and can take axial load from both directions.
Thrust bearings with rollers as rolling element can
accommodate a certain amount of radial load along
with axial loads.
Ball Bearing unit
A ball bearing unit is comprised of a ball bearing inserted into various types of housings. The housing can
be bolted onto machinery and the inner ring can be easily mounted on the shaft with a set screw. This
means the bearing unit can support rotating equipment without special design to allow for mounting. A variety
of standardized housing shapes is available, including pillow and flange types. The outer diameter of the
bearing is spherical just like the inner diameter of the housing, so it capable of aligning itself on the shaft. For
lubrication, grease is sealed inside the bearing, and particle penetration is prevented by a double seal with
3 lip
UCP UCF UCFL UCFC UCT
4
Rolling Bearings Classification
Bearing Designation, prefix and suffix
Rolling bearing part numbers indicate bearing type, dimensions, tolerances, internal construction, and other
related specifications. Bearing numbers are comprised of a “basic number” followed by “supplementary codes.”
The basic number indicates general information about a bearing, such as its fundamental type, boundary
dimensions, series number, bore diameter code and contact angle. The supplementary codes derive from
prefixes and suffixes which indicate a bearing’s tolerance, internal clearance, and related specifications.
Ball bearings
6 2 0 4 ZZ NR C3
Radial clearance
Snap ring groove with snap ring
Both side metal shields
Bore size
Diameter series
Single row deep groove ball bearings
Bearing type Bearing series Diameter series
Single row ball 68,69,160,60,62,63,64,622,623 8,9,0,0,2,3,4,2,3
bearings
Double row ball 42,43 2,3
bearings
Prefix Description Suffix Description
F Flanged outer ring CM Electric motor clearance
RLS Inch type ball bearing C2 Radial clearance lesser than normal
RMS Inch type ball bearing C3 Radial clearance higher than normal
C4 Radial clearance higher than C3
DDU Bearings with non contact type
rubber seals
LLU Bearings with contact type rubber
seals
M Machined brass cage
N With snap ring groove
NR Snap ring groove with snap ring
P6 Precision class 6
Z With one side metal shield
ZZ With both side metal shield
ZNR With one side metal shield and snap
ring groove with snap ring
5
Rolling Bearings Classification
Self Aligning ball bearings
1209 K + H
Bearing with sleeve
Tapered bore
Bore size
Diameter Series
Self aligning ball bearings
Bearing type Bearing Series Diameter series
Self aligning ball bearings 12,22,13,23 2,2,3,3
Prefix Description Suffix Description
K With tapered bore
+H With adapter sleeve
Angular Contact ball bearings
7205B
Contact angle
Bore size
Diameter series
Angular contact ball bearings
Bearing type Bearing Series Diameter series
Angular contact ball bearings 72.73 2,3
Double row angular contact ball bearing with filling 32,33 2,3
slot (maximum capacity)
Double row angular contact ball bearing without 52,53 2,3
filling slot
Prefix Description Suffix Description
A 30 degree contact angle
B 40 degree contact angle
TVP With reinforced polyamide cage
C 15 degree contact angle
M Brass cage
6
Rolling Bearings Classification
Cylindrical roller bearings
N U 2 2 0 8 M C3
Radial clearance
Machined brass cage
Bore Size
Diameter series
Width series
NU type cylindrical roller bearings
Bearing type Bearing series Diameter series
Cylindrical roller bearing 2,22,3,32 2,2,3,3
Prefix Description Suffix Description
N Bearings with both side sliding outer ring N With snap ring groove
NJ Bearings with one side sliding inner ring NR Snap ring groove and snap ring
NU Bearings with both side sliding inner ring V Full compliment bearings
NUP Bearing with fixed inner and outer ring
Tapered Roller bearings
32217JR
High load carrying capacity
Bore size
Diameter series
Width series
Tapered roller bearings
Bearing type Bearing Series Diameter series
Taper roller bearing 320,330,331,302,322,332,303,313,323 0,0,1,2,2,2,3,3,3
Prefix Description Suffix Description
HC Hi-cap D Steep contact angel (24°~32°) metric
series
HM Heavy medium duty inch series JR High load carrying capacity
JL J series tapper roller bearings
JLM J series light medium duty inch series
L Light duty inch series
LM Light medium duty inch series
M Medium duty inch series
7
Rolling Bearings Classification
Spherical Roller bearings
2 2 3 0 8 K MB W33
With lubricating holes and groove
Machined brass cage
Tapered bore 1:12
Bore size
Diameter series
Width series
Spherical roller bearings
Bearing type Bearing Series Diameter series
Spherical roller bearings 239,230,240,231,241,222,232,213,223, 9,0,0,1,1,2,2,3,3
Prefix Description Suffix Description
CC Steel cage
CA Machined single brass cage
K Tapered bore 1:12
K30 Tapered bore 1:30
M Machined brass cage
MA Machined brass cage outer ring guided
MB Machined brass cage inner ring guided
W33 Lubricating holes and groove on outer ring
Thrust ball bearings
51120M
Brass cage
Bore size
Diameter series
Height series
Thrust ball bearings
Bearing type Bearing Series Diameter series
Thrust ball bearing 511,512,513 1,2,3
Prefix Description Suffix Description
M Machined brass cage
