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The basic designation identifies:
• Product type• Standard design• Size
The supplementary designation identifies:
• Alternative design (variants)• Bearing components• Types of special bearings
SKF Bearing Designations
The Supplementary Designations identify
Alternative Designs ( Variants ) Bearing Components Type of Special Bearing
Supplementary designation consists of
Prefixes Suffixes
Basic Designation for Metric Bearings
Consists of 5 digits First digit denotes Bearing Type Second digit denotes Width /
Height Third digit denotes OD Fourth & fifth digits denote ID
Dimension Series
Diameter Series Width Series Dimension Series
3
2
0
0 1 2 3
03
02
00
13
1210
23
22
20 3032
33
How the Designation System WorksBearing types
Radial bearings, width (B, T) Thrust bearing, height (H)
Outside diameter (D)
Bearing size d/5
(30 mm bore diameter)
Basic Series Designations: Standard Inch Size Bearings
L L L L
Bearingtype
Bearingseries
Bore1/8’s
of inch
Standard Inch Size Bearing Types
deep groove ball bearings
angular contact ball bearings
self-aligning ball bearings
cylindrical roller bearings
RLS RMS
ALS AMS
RL RM
CRL CRM
L: light series M: medium series
Example : Inch Size Designations
deep groove ball, d = 1 1/4˝, light
cylindrical roller, d = 3˝, medium
self-aligning ball, d = 2˝, light
angular contact ball, d = 5˝, light
RLS 10
CRM 24
RL 16
ALS 40
thrust ball, d = 2 1/2˝ O 20
Inch Size Taper Roller Bearings: Cups and Cones
Inch taper rollerbearings are designedaround roller & cageassemblies, and belong to families
: Basic design(family)
The supplementary designation identifies:
• Variants – deviations from standard design
• Grouped into four categories
• Added to basic designation in a specific order, where
more than one deviation applies
SKF Bearing Designations
Categories of Supplementary Designations
Category 1 : Modified Internal Design
Category 2 : Modified External Design
Category 3 : Modified Cage Design
Category 4 : Modifications to enhance Performance
Category 1: Modified Internal Design
A AC
B BE
C and combinations thereof such as CA/CB/CCCAC
D
E EC
Category 1: Modified Internal Design
A : * Transitional Designation / changed after a period e.g., 4210 A : DRDGBB without filling slot * Contact Angle 300 in SRACBB e.g., 7056 A
B : * Contact Angle 400 in SRACBB e.g., 7210 B * Steep Contact Angle in TRB e.g., 32210 B
Category 1: Modified Internal Design
C : * Contact Angle 150 in SRACBB e.g., 7012 C * SRB with loose Guide Flange , symmetrical rollers and pressed steel cage of window design
AC :* Contact Angle 250 in SRACBB e.g., 7210 AC D :* DRACBB with two part Inner Ring and Contact Angle of 450
Category 1: Modified Internal Design
E : * Larger ball or Roller diameter e.g., 29320 E
CA :* SRB with loose guide ring but two integral flanges with machined brass cage e.g., 23180 CA/W33 * ACBB for universal mounting with low axial clearance when mounted in pair
CAC :* SRB of CA design but with improved roller guidence
Category 1: Modified Internal Design
CB : * ACBB for universal mounting with axial clearance larger than CA when mounted in pair
CC :* ACBB for universal mounting with axial clearance larger than CB when mounted in pair * SRB of C design but with improved roller guidance
EC : * Single Row CRB with a greater number of larger rollers than the original design, and increased axial load carrying capacity in Flanged executions e.g., NU 320 EC / NJ 320 EC
Category 1: Modified Internal Design
GA : * ACBB for universal mounting with light preload when mounted in pair
GB :* ACBB for universal mounting with axial preload larger than GA when mounted in pair GC : * ACBB for universal mounting with axial preload larger than GB when mounted in pair
Category 2: Modified External Design
K : * Tapered Bore ( Taper 1 : 12 )K 30 : * Tapered Bore ( Taper 1 : 30 )N : * Snap ring groove on bearing outer diameterN1 : * One locating slot on outside edge of outer ringN2 : * Two diametrically opposite locating slots on outside edge of outer ring N4 : * N + N2. Locating slots on side opposite to snap ring grooveN6 : * N + N2. Locating slots on same side as snap ring grooveNR : * Snap ring groove on bearing outer diameter along with an appropriate snap ring
Category 2: Modified External Design
P : * SRB with two part outer ringPR : * SRB with two part outer ring, with calibrated spacer in betweenR : * Integral flange on outer ring outer diameter- RS : * NRB fitted with synthetic rubber seal on one side- 2RS : * NRB fitted with synthetic rubber seals on two sides- RS1 : * Rubbing seal of synthetic rubber with sheet steel reinforcement fitted on one side - 2RS1 : * Rubbing seal of synthetic rubber with sheet steel reinforcement fitted on both sides
Category 2: Modified External Design
-RS2 : * Rubbing seal consisting of sheet steel washer with vulcanized rubber fitted on one side - 2RS1 : * Rubbing seal consisting of sheet steel washer with vulcanized rubber fitted on both sides -RZ : * Ball bearing with low friction seal consisting
of sheet steel washer with vulcanized rubber fitted on one side-2RZ : * Ball bearing with low friction seal consisting
of sheet steel washer with vulcanized rubber fitted on both sides
Category 2: Modified External Design
X : * One or more of bearing external dimensions altered to fully comply with ISO standards
- Z : * Metallic non-rubbing seal fitted on one side
- 2Z : * Metallic non-rubbing seal fitted on both sides
Category 3: Modified Cage Design
F : * Machined Steel or SG Iron cageFA : * F Cage centred on outer ringFB : * F Cage centred on inner ring FE : * Machined Steel Cage phosphatedH : * Pressed cage of hardened sheet steel J : * Pressed cage of unhardened sheet steel JA : * J Cage centred on outer ringJE : * J Cage phosphatedL : * Machined light alloy cageLA : * L Cage centred on outer ringLB : * L Cage centred on inner ring
Category 3: Modified Cage Design
M : * Machined Brass cageMA : * M Cage centred on outer ringMB : * M Cage centred on inner ring MP : * M Cage window typeP : * Moulded cage made of glass fibre reinforced polyamide 6.6 TN : * Moulded cage made of plasticY : * Pressed Brass cageV : * Full complement bearing ( without cage )
Category 4: Modifications to enhance Performance
/CL7A: * Standard SKF quality for Pinion Bearings/CL7C: * Special SKF quality for Pinion Bearings
/CN : * Normal internal clearance. This usually used followed by H/M/L/P to denote part or displaced range e.g.:
CNH : * Upper half of Normal CNM : * Two middle quarters of Normal CNL : * Lower half of Normal CNP : * Upper half of Normal &
Lower half of C3
Category 4: Modifications to enhance Performance
/C1 : * Internal clearance less than C2 /C2 : * Internal clearance less than Normal /C3 : * Internal clearance more than Normal/C4 : * Internal clearance more than C3 /C5 : * Internal clearance more than C4
A letter H/M/L/P following the clearance designation denotes part or displaced range.
/C01 : * Reduced tolerance for running accuracy of I/R/C02 : * Extra reduced tolerance for running accuracy of I/R : less than C01
Category 4: Modifications to Enhance Performance
C1 clearance less than C2C2 clearance less than NormalC3 clearance greater than NormalC4 clearance greater than C3C5 clearance greater than C4
Radial internalclearance
Axial internalclearance
Suffix Range for Internal Clearances
Category 4: Modifications to enhance Performance
/C03 : * Reduced tolerance for running accuracy of O/R/C04 : * Extra reduced tolerance for running accuracy of O/R : less than C03
/C05 : * C01 + C03 /C06 : * C02 + C03/C05 : * C01 + C04 /C06 : * C02 + C04
/C10 : * Reduced tolerance for bore & OD. In case of tapered bore, refers to only OD./C20 : * Bore diameter tolerance less than C10
Category 4: Modifications to enhance Performance
/C30 : * Reduced bore diameter tolerance, towards standard minimum limit.
/C40 : * OD tolerance less than C10 /C50 : * Reduced OD tolerance, towards standard minimum limit.
/C60 : * C20 + C50/C70 : * C20 + C40 /C80 : * Reduced height tolerance for thrust bearings
/C15 : * C10 + C05/C18 : * C10 + C08/C78 : * C70 + C08
Category 4: Modifications to enhance Performance
/DB : * Two single row DGBB/ACBB/TRB, paired for mounting in back-to-back arrangement./DF : * Two single row DGBB/ACBB/TRB, paired for mounting in face-to-face arrangement./DT : * Two single row DGBB/ACBB/TRB, paired for mounting in tandem
/HA : * Case hardened bearing or bearing components. For closer identification, it is followed by one of
following numbers : 0/1/2/3/4/5/6/7 e.g., 1 Both rings
2 Outer ring 5 Rolling elements etc.
Category 4: Modifications to enhance Performance
/HT : * Bearing supplied with High Temperature ( upto +1300 C) grease /LHT : * Bearing supplied with Low as well as High Temperature ( -40 to +1400 C) grease/LT : * Bearing supplied with Low Temperature ( upto -500 C) grease/MT : * Bearing supplied with Medium Temperature ( -30 to +1100 C) grease
Category 4: Modifications to enhance Performance
/P4 : * Dimensional and running accuracy to ISO tolerance class 4. /P4A : * Dimensional accuracy to ISO tolerance class 4 and and running accuracy to AFBMA class 9. /P5 : * Dimensional and running accuracy to ISO tolerance class 5 ( More accurate than P6)./P6 : * Dimensional and running accuracy to ISO tolerance class 6. /P43 : * P4 + C3/P52 : * P5 + C2/P62 : * P6 + C2/PA9 : * Dimensional and running accuracy to AFBMA
class 9.
Category 4: Modifications to enhance Performance
/SP : * Special Precision, dimensional accuracy approx. corresponding to P5 and running accuracy
approx. to P4/S0 : * Bearing ring dimensionally stabilized to optg.
temperatures upto + 1500C /S1 : * Bearing ring dimensionally stabilized to optg.
temperatures upto + 2000C /S2 : * Bearing ring dimensionally stabilized to optg.
temperatures upto + 2500C /S3 : * Bearing ring dimensionally stabilized to optg.
temperatures upto + 3000C/S4 : * Bearing ring dimensionally stabilized to optg.
temperatures upto + 3500C
Category 4: Modifications to enhance Performance
/UP : * Ultra Precision, dimensional accuracy approx. corresponding to P4 and running accuracy
better than P4/W20 : * Three lubrication holes in outer ring /W33 : * Lubricating groove and three lubrication holes
in outer ring /Vxxxx: * V plus a second letter followed by a three figure number denoting variants not covered by “logical” supplementary designations. e.g:
VA 201 : Bearings for Kiln Trucks VA 301 : Bearings for Traction Motors
Category 4: Modifications to Enhance Performance
P0 1 Normal P0
P6 3 P6 P6
P5 5 P5 P5
P4 7 SP P4P4A
P2 9 UP P2PA9A
ToleranceISO
ToleranceABEC
ToleranceSKF
ToleranceRHP / NSK
SKF Bearing Designations
The sequence of writing the designations:
• Prefix – if any
• Basic designation
• Supplementary designation of category 1
• Supplementary designation of category 2
• Supplementary designation of category 3
• Stroke
• Supplementary designation of category 4
SKF Bearing DesignationsThe sequence of writing the designations:
• Where two suffixes follow one another, the first ending
with a figure and the second starting with one, a stroke
is to be used
e.g: 6310 / C4/ 630251
• Where a suffix for a divided clearence range is followed
by a suffix for type of grease, a stroke is to be used
e.g : 6205-2Z/C2L/HT51 (C2L + HT51)
but : 6205-2Z/C2 LHT51 (C2 + LHT51)
Letter Year Year Year Year Letter Year Year Year Year
A 1910 1934 1958 1981 N 1922 1946 1970 1993B 1911 1935 1959 1982 O 1923 1947 1971 1994C 1912 1936 1960 1983 P 1924 1948 1972 1995
D 1913 1937 1961 1984 R 1925 1949 1973 1996E 1914 1938 1962 1985 S 1926 1950 1974 1997F 1915 1939 1963 1986 T 1927 1951 1975 1998
G 1916 1940 1964 1987 U 1928 1952 1976 1999E 1917 1941 1965 1988 V 1929 1953 – –J 1918 1942 1966 1989 W 1930 1954 1977 2000
K 1919 1943 1967 1990 X 1931 1955 1978 2001L 1920 1944 1968 1991 Y 1932 1956 1979 2002M 1921 1945 1969 1992 Z 1933 1957 1980 2003
Date CodesThe Year Letter to be marked on a bearing or a bearing accessory shall
comprise a single letter in accordance with the table below