NSK bearing designation | nomenclature | prefixes | suffixes

Order codes for NSK bearings are made up of a combination of letters and numbers. This alphanumeric combination denotes the type, size and structure of the NSK bearing. Within each code, a distinction is made between the basic designation and any suffixes and/or prefixes. The basic designation of NSK bearing indicates the NSK bearing type and the bore size. These basic designations are defined in the German DIN 623 standard and the relevant ISO standard. For most NSK bearing types, the basic designation is made up of numbers, but some are alphanumeric.

Prefixes and suffixes denote special modificaitons, for example if the internal clearance or accuracy deviate from the norm. the use of prefixes and suffixes is only partially standardised. Suffixes differ the most, with the various bearing manufacturers using different codes for certain modifications. Please refer to NSK bearing cross reference to compare with other manufactures' designations.

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.

The diagram below show how the order codes are made up. There should be spaces separating the individual sections of an order code from one another.
NSK bearing designation

NSK bearing designation system

Basic designation of NSK bearing

The basic designation consists of the code for the NSK bearing series and the code for the bearing bore. This most important codes for metric bearing series are list in table below.

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
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 bearings with flat seats 511
512
513
514
522
523
524
5 1
1
1
1
2
2
2

1
2
3
4
2
3
4

Spherical thrust roller bearings 292
293
294
2 9 2
3
4

NSK bearing numbers, radial bearings for various dimensional series
Comparison of cross sections of NSK radial bearings for various dimensional series

NSK bearing numbers, thrust bearings for various dimensional series
Comparison of cross sections of NSK thrust bearings for various dimensional series

Designation for the bearing bore

The designation for the NSK bearing bore indicates the bearing's bore size. A two-digit number is used for bore sizes from 20mm to 480mm. This number is multiplied by five to give the bore size.

For example, the code 6318 stands for a deep groove ball bearing with a bore size of 90 mm.

Diameters of 10, 12, 15 and 17 are an exception. In these cases, 00 indicates a diameter of 10 mm, 01 stands for 12 mm, 02 means 15 mm and the code 03 corresponds to a diameter of 17 mm.

The diameter is stated in mm for bore sizes up to 9 mm and over 480 mm. However, a miniature ball bearings with the code 608DDWMC3E has a bore size of 8 mm and a spherical roller bearing designated as 230/560 CAM E4 has a bore size of 560 mm.

NSK bearing nomenclature

Prefixes and suffixes can have different meanings depending on the NSK bearing series in question.

NSK bearing prefixes

Prefixes are used comparatively rarely. They serve almost exclusive ly to indicate individual components of complete bearings or to designate miniature bearings. The Code are listed in table below.

NSK prefixe Defintion
B Bearing with special dimensions, example: B 15
F Bearing with flanged outer ring, example: F684ZZ MC3
HR For NSK tapered roller bearings and deep groove ball bearings: higher load rating.
MF NSK miniature metric bearing with special dimensions and flanged outer ring
MR NSK miniature metric bearing with special dimensions. Example: MR126ZZ MC3
R Bearing outer ring with rollers and cage, no inner ring. Exampl: R NU 207
R Miniature imperial bearing, example: R 4Z MC3

NSK bearing suffixes

A loarge number of suffixes are used to denote structural modifications. Specifically, the suffixes provide information about the:

  • Cage Type
  • Internal design
  • seal
  • lubricant used
  • tolerances
  • internal clearance
  • external design

1, Contact angle symbol nomenclature

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 nomenclature

  • 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

 

3, Material symbol

  • g: Case-hardened steel used in rings, rolling elements
  • h: stainless steel used in rings, rolling elements

4, Cage symbol nomenclature

  • 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

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

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
  • HJ: thrust collar designation

11, Grease symbol

  • AS2: shell alvania grease S2
  • ENS: ENS grease
  • NS7: ns hI-LUBE
  • PS2: Multemp PS No. 2

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