Prefixes
Prefixes are used to identify components of a bearing and are usually then followed by the designation of the complete bearing, or used to avoid confusion with other bearing designations. Further information can be found in SKF catalogues or online at skf.com/bearings.
For customized bearing designs, the following prefixes are used. The complete bearing designation consists of the prefix and a drawing number.
Examples:
BB1 Single row ball bearing, customized design
BC1 Single row cylindrical roller bearing, customized design
BT1 Single row tapered roller bearing, customized design
Suffixes
The most common designation suffixes used to identify certain features of SKF bearings in railway applications are explained below. For additional information, contact the SKF application engineering service.
B20 Reduced width tolerance
C3 Bearing internal clearance greater than Normal (CN)
C4 Bearing internal clearance greater than C3
C4H Bearing internal clearance greater than C3 (upper half of C4 clearance) C5 Bearing internal clearance greater
than C4
C5H Bearing internal clearance greater than C4 (upper half of C5 clearance) CA 1. Spherical roller bearing of
C design, but with retaining flanges on the inner ring and a machined cage
2. Single row angular contact ball bearing for universal matching.
Two bearings arranged back-to-back or face-to- face will have an axial internal clearance smaller than Normal (CB) before mounting
CB 1. Single row angular contact ball bearing for universal matching.
Two bearings arranged back-to-back or face-to-face will have a Normal axial internal clearance before mounting
2. Controlled axial clearance of a double row angular contact ball bearing
CC 1. Spherical roller bearing of C design but with enhanced roller guidance
2. Single row angular contact ball bearing for universal matching.
Two bearings arranged back-to-back or face-to-face will have an axial internal clearance larger than Normal (CB) before mounting CL7C High-performance design for
tapered roller bearings in pinion arrangements
DB Matched single row tapered roller bearing pair, arranged back-to-back.
A number immediately following the DB identifies the design of the intermediate rings
MA Machined brass cage, outer ring centred, used for oil lubrication ML, MP Machined one-piece window-type
brass cage, outer ring centred, used for oil lubrication
MR Machined one-piece window-type brass cage, rolling element centred MR3D Machined one-piece window-type
brass cage, special design N Snap ring groove in the outer ring N1 One locating slot (notch) in one outer
ring side face
N2 Two locating slots (notches) 180°
apart in one outer ring side face N3 Snap ring groove in the outer ring,
one locating slot (notch) in one outer ring side face
P4 Dimensional and running accuracy to ISO tolerance class 4
P5 Dimensional and running accuracy to ISO tolerance class 5
P54 P5 + C4
P6 Dimensional and running accuracy to ISO tolerance class 6
P63 P6 + C3 P64 P6 + C4 P65H P6 + C5H
Q Optimized contact geometry and surface finish
RS1 Sheet steel reinforced contact seal of acrylonitrile-butadiene rubber (NBR) on one side of the bearing
2RS1 RS1 contact seal on both sides of the bearing
RSH Sheet steel reinforced contact seal of acrylonitrile-butadiene rubber (NBR) on one side of the bearing
2RSH RSH contact seal on both sides of the bearing
RSL Sheet steel reinforced low-friction contact seal of acrylonitrile-butadiene rubber (NBR) on one side of the bearing
2RSL RSL low-friction contact seal on both sides of the bearing
RZ Sheet steel reinforced low-friction seal of acrylonitrile-butadiene rubber (NBR)
2RZ RZ low-friction seal on both sides of the bearing
S0 Bearing rings or washers dimensionally stabilized up to +150 °C
T T, followed by a figure, identifies the total width of single row tapered roller bearing pairs arranged back-to-back or in tandem
DF Matched single row tapered roller bearing pair, arranged face-to-face.
A number immediately following the DF identifies the design of the intermediate ring
DT Matched single row tapered roller bearing pair, arranged in tandem. A number immediately following the DT identifies the design of the intermediate rings
EC Optimized internal design incorporating more and/or larger rollers and with modified roller end/
flange contact
G Single row angular contact ball bearing for universal matching. Two bearings arranged back-to-back or face-to-face will have a "Normal"
axial clearance
GA Single row angular contact ball bearing for universal matching. Two bearings arranged back-to-back or face-to-face will have a light preload GB Single row angular contact ball
bearing for universal matching. Two bearings arranged back-to-back or face-to-face will have a moderate preload
GC Single row angular contact ball bearing for universal matching. Two bearings arranged back-to-back or face-to-face will have a heavy preload
HA Case-hardened bearing or bearing components. For closer
identification, HA is followed by one of the following figures
0: Complete bearing 1: Outer and inner rings 2: Outer ring
3: Inner ring
4: Outer ring, inner ring and rolling elements
5: Rolling elements
6: Outer ring and rolling elements 7: Inner ring and rolling elements HB Bainite-hardened bearing or bearing
component. For closer identification, HB is followed by one of the figures explained under HA
HC Bearing or bearing components of ceramic. For closer identification, HC is followed by one of the figures explained under HA
Example: HC5 Rolling elements made of silicon nitride
J, J1, J2 Pressed window-type steel cage M Machined brass cage, rolling element
centred
3
Examples for VA and VL designations VA301 Bearing for traction motors
•
VA3091 Bearing for traction motors with
•
aluminium oxide coated outside surface of outer ring for electrical resistance up to 1 000 V DC
VL0241 Aluminium oxide coated outside
•
surface of outer ring for electrical resistance up to 1 000 V DC
VL0271 Aluminium oxide coated outside
•
surface of inner ring for electrical resistance up to 1 000 V DC
Additional suffixes concerning INSOCOAT bearings are listed on page 117.
TNH Injection moulded cage of glass fibre reinforced polyetheretherketone (PEEK), rolling element centred TN9 Injection moulded cage of glass fibre
reinforced polyamide 66, rolling element centred
V... V combined with a second letter, identifies a variant group, and followed by a three- or four-figure number denotes variants not covered by “standard” designation suffixes.
VA: Application oriented variants VB: Boundary dimension deviations VE: External or internal deviations VL: Coatings
VQ: Quality and tolerances other than standard
VS: Clearance and preload VT: Lubrication
VU: Miscellaneous applications Z Shield of pressed sheet steel on one
side of the bearing
2Z Z shield on both sides of the bearing