NSK bearing numbers are alphanumeric combinations that indicate the NSK bearing type, boundary dimensions, dimensional and running accuracies, internal clearance, and other related specifications.

1. NSK bearing nomenclature, Formulation of NSK bearing
numbers
NSK bearing numbers are alphanumeric combinations that indicate the NSK bearing type, boundary dimensions,
dimensional and running accuracies, internal clearance, and other related specifications. NSK bearing nomenclature
consist of basic numbers and supplementary symbols. The boundary dimensions of commonly used NSK
bearings mostly conform to the organizational concept of ISO, and the NSK bearing numbers of these standard
bearings are specified by JIS B 1513 (Bearing numbers for rolling bearings). Due to a need for more detailed
classification, NSK uses auxiliary symbols other than those specified by JIS.
NSK bearing numbers nomenclature consist of a basic number and supplementary symbols. The basic NSK number
indicates the NSK bearing series (type) and the width and diameter series as shown in table below. NSK basic
numbers supplementary symbols, and the meanings of common numbers and symbols are listed in table below. the
contact angle symbols and other supplementary designations are also shown in table.
NSK bearing series symbols
Bearing type Bearing series
symbols
Type symbols Dimension symbols
Width symbols Diameter symbols
single-row deep
groove ball
bearings
68
69
60
62
63
6 (1)
(1)
(1)
(0)
(0)
8
9
0
2
3
Single-row
angular contact
ball bearings
79
70
72
73
7 (1)
(1)
(0)
(0)
9
0
2
3
Self-aligning ball
bearings
12
13
22
23
1
1
(1)
(1)
(0)
(0)
2
2
2
3
2
3
Single-row
cylindrical roller
bearings
NU10
NU2
NU22
NU3
NU23
NU4
NU 1
(0)
2
(0)
2
(0)
0
2
2
3
3
4

2. NJ2
NJ22
NJ3
NJ23
NJ4
NJ (0)
2
(0)
2
(0)
2
2
3
3
4
NUP2
NUP22
NUP3
NUP23
NUP4
NUP (0)
2
(0)
2
(0)
2
2
3
3
4
N10
N2
N3
N4
N 1
(0)
(0)
(0)
0
2
3
4
NF2
NF3
NF4
NF (0) 2
3
4
Double-row
cylindrical roller
bearings
NNU29
NN30
NNU
NN
4
3
9
0
Needle roller
bearings
NA48
NA49
NA59
NA69
NA 4
4
5
6
8
9
9
9
Tapered roller
bearings
329
320
330
331
302
322
332
303
323
3 2
2
3
3
0
2
3
0
2
9
0
0
1
2
2
2
3
3
Spherical roller
bearings
230
231
222
232
213
223
2 3
3
2
3
0
2
0
1
2
2
3
3
Thrust ball 511 5 1 1

3. bearings with flat
seats
512
513
514
522
523
524
1
1
1
2
2
2
2
3
4
2
3
4
Spherical thrust
roller bearings
292
293
294
2 9 2
3
4
NSK bearing nomenclature
1, Contact angle symbol
Angular contact ball bearings
 A: Standard contact angle of 30°
 A5: Standard contact angle of 25°
 B: Standard contact angle of 40°
 CStandard contact angle of 15°
Tapered roller bearings
 Ommitted: contact angle less than 17°
 C: contact angle about 20°
 D: contact angle about 28°
2, Internal design symbol
 A: Internal design differs from standard one.
 J: Smaller diameter of outer ring raceway, contact angle, and outer ring width of tapered roller bearings
conform to ISO 355
For high capacity NSK bearings
 C, CA, CD, EA: spherical roller bearings
 E: cylindrical roller bearings
 E: spherical thrust roller bearings

4. 3, Material symbol
 g: Case-hardened steel used in rings, rolling elements
 h: stainless steel used in rings, rolling elements
4, Cage symbol
 M: machined brass cage
 W: pressed steel cage
 T: synthetic resin cage
 V: without cage
5, External features
Seals, shields symbol
 Z, ZS: shield on one side only
 ZZ, ZZS: shields on both sides
 DU: contact rubber seal on one side only
 DDU: contact rubber seals on both sides
 B: Non-contact rubber seal on one side only
 DDU: Non-contact rubber seals on both sides
Symbol for design of rings
 K: tapered bore of inner ring (Taper 1:12)
 K30: tapered bore of inner ring (Taper 1:30)
 E: Notch or lubricating groove in ring
 E4: Lubrication groove in outside surface and holes in outer ring
 N: snap ring groove in outer ring
 NR: snap ring groove with snap ring in outer ring
6, Arrangement Symbol
 DB: back-to-back arrangement
 DF: face-to-face arrangement
 DT: tandem arrangement
7, internal clearance Symbol and preload symbol

5. for all radial bearings
 C1: clearance less than C2
 C2: clearance less than CN
 Omitted: CN clearance
 C3: clearance GREATER than CN
 C4: clearance GREATER than C3
 C5: clearance GREATER than C4
for Non-interchangeable cylindrical roller bearings
 CC1: clearance less than CC2
 CC2: clearance less than CC
 CC: Normal clearance
 CC3: clearance GREATER than CC
 CC4: clearance GREATER than CC3
 CC5: clearance GREATER than CC4
for Extra-small and NSK Miniature ball bearings
 MC1: clearance less than MC2
 MC2: clearance less than MC3
 MC3: Normal clearance
 MC4: clearance GREATER than MC3
 MC5: clearance GREATER than MC4
 MC6: clearance GREATER than MC5
CM: Clearance in NSK Deep groove ball bearings and Cylindrical roller bearings(CM or CT) for electric Motors.
Preload of angular contact ball bearings
 EL: extra light preload
 L: light preload
 M: medium preload
 H: heavy preload

6. 8, Tolerance class symbol
 Omitted: ISO Normal
 P6: ISO class6
 P6X: ISO class6X
 P5: ISO class5
 P4: ISO class4
 P2: ISO class2
for ABMA tapered roller bearing
 Omitted: class 4
 PN2: class 2
 PN3: class 3
 PN0: class 0
 PN00: class 00
9, special specification symbol
Bearings treated for dimensional stabilication
 X26: working temperature lower than 150°C
 X28: working temperature lower than 200°C
 X29: working temperature lower than 250°C
spherical roller bearings
 s11: dimensional stabiliging treatment working temperature lower than 200°C
10, Spacer or sleeve symbol
 +K: Bearings with outer ring spacers
 +L: Bearings with inner ring spacers
 +KL: Bearings with both inner and outer ring spacers
 H: adapter designation
 AH: withdrawal sleeve designation

7.  HJ: thrust collar designation
11, Grease symbol
 AS2: shell alvania grease S2
 ENS: ENS grease
 NS7: ns hI-LUBE
 PS2: Multemp PS No. 2