The nomenclature of most rolling bearings follow a designation system. The complete bearing designation is composed of a basic number with or without one or more supplementary prefixes and suffixes.
| Prefix | Bearing Basic Designation | Suffix | |
| Bearing series code | Bearing bore code | ||
The basic bearing number indicates the bearing type, basic design, and the bore size. For most bearing types, the basic bearing designation is made up of numbers, but some are alphanumeric.
Prefixes and suffixes denote special modifications including internal design, seals, cage, materials, tolerance, internal clearance, preload, lubrication, etc. Prefixes and suffixes differ the most, with the various bearing manufactures using different codes for certain modifications. Bearing interchange chart helps you to compare different bearing manufactures' nomenclature.
1, Basic bearing number designations
The basic designation consists of the bearing series code and bore code. And it typically contains three to five digits.
1.1, Bearing series nomenclature
| Prefix | Bearing Basic Designation | Suffix | ||
| Bearing series code | Bearing bore code | |||
| Bearing type | Dimension series | |||
Bearing series code have the following meaning:
- The first digit or letter or combination of letters identifies the bearing type and eventually a basic variant.
- The following two digits identify the ISO dimension series. The first digit indicates the width or height series (dimensions B, T or H). The second digit identifies the diameter series (dimension D).
Bearing series code
| Bearing type | Bearing series code | Type code | Dimension series code | |
|---|---|---|---|---|
| Width series | Diameter series | |||
| Single-row deep groove ball bearing | 617 | 6 | 1 | 7 |
| 618 | 6 | 1 | 8 | |
| 619 | 6 | 1 | 9 | |
| 160 | 6 | (0) | 0 | |
| 60 | 6 | (1) | 0 | |
| 62 | 6 | (0) | 2 | |
| 63 | 6 | (0) | 3 | |
| 64 | 6 | (0) | 4 | |
| Double-row deep groove ball bearing | 42 | 4 | (2) | 2 |
| 43 | 4 | (2) | 3 | |
| Single-row angular contact ball bearing | 719 | 7 | 1 | 9 |
| 70 | 7 | (1) | 0 | |
| 72 | 7 | (0) | 2 | |
| 73 | 7 | (0) | 3 | |
| 74 | 7 | (0) | 4 | |
| Double-row angular contact ball bearing | 32 | (0) | 3 | 2 |
| 33 | (0) | 3 | 3 | |
| Self-aligning ball bearing | 12 | 1 | (0) | 2 |
| 22 | (1) | 2 | 2 | |
| 13 | 1 | (0) | 3 | |
| 23 | (1) | 2 | 3 | |
| Single-row cylindrical roller bearing | NU 10 | NU | 1 | 0 |
| NU 2 | NU | (0) | 2 | |
| NU 22 | NU | 2 | 2 | |
| NU 32 | NU | 3 | 2 | |
| NU 3 | NU | (0) | 3 | |
| NU 23 | NU | 2 | 3 | |
| NU 4 | NU | (0) | 4 | |
| Double-row cylindrical roller bearing | NNU 49 | NNU | 4 | 9 |
| NN 30 | NN | 3 | 0 | |
| Single-row needle roller bearing | NA 48 | NA | 4 | 8 |
| NA 49 | NA | 4 | 9 | |
| NA 59 | NA | 5 | 9 | |
| Double-row needle roller bearing | NA 69 | NA | 6 | 9 |
| Tapered roller bearing | 329 | 3 | 2 | 9 |
| 320 | 3 | 2 | 0 | |
| 330 | 3 | 3 | 0 | |
| 331 | 3 | 3 | 1 | |
| 302 | 3 | 0 | 2 | |
| 322 | 3 | 2 | 2 | |
| 332 | 3 | 3 | 2 | |
| 303 | 3 | 0 | 3 | |
| 313 | 3 | 1 | 3 | |
| 323 | 3 | 2 | 3 | |
| Spherical roller bearing | 239 | 2 | 3 | 9 |
| 230 | 2 | 3 | 0 | |
| 240 | 2 | 4 | 0 | |
| 231 | 2 | 3 | 1 | |
| 241 | 2 | 4 | 1 | |
| 222 | 2 | 2 | 2 | |
| 232 | 2 | 3 | 2 | |
| 213 | 2 | 1 | 3 | |
| 223 | 2 | 2 | 3 | |
| Single direction thrust ball bearing | 511 | 5 | 1 | 1 |
| 512 | 5 | 1 | 2 | |
| 513 | 5 | 1 | 3 | |
| 514 | 5 | 1 | 4 | |
| Single direction thrust ball bearing with spherical back face | 532 | 5 | 3 | 2 |
| 533 | 5 | 3 | 3 | |
| 534 | 5 | 3 | 4 | |
| Double direction thrust ball bearing | 522 | 5 | 2 | 2 |
| 523 | 5 | 2 | 3 | |
| 524 | 5 | 2 | 4 | |
| Double direction thrust ball bearing with spherical back faces | 542 | 5 | 4 | 2 |
| 543 | 5 | 4 | 3 | |
| 544 | 5 | 4 | 4 | |
| Spherical thrust roller bearing | 292 | 2 | 9 | 2 |
| 293 | 2 | 9 | 3 | |
| 294 | 2 | 9 | 4 | |
Bearing type code meaning
| Code | Bearing type | Code | Bearing type |
|---|---|---|---|
| 0 | Double row angular contact ball bearing | 6 | Single row deep groove ball bearing |
| 1 | Self-aligning ball bearing | 7 | Single row angular contact ball bearing |
| 2 | Spherical roller bearing, spherical roller thrust bearing | 8 | Cylindrical roller thrust bearing |
| 3 | Tapered roller bearing | N | Cylindrical roller bearing |
| 4 | Double row deep groove ball bearing | QJ | Four-point contact ball bearing |
| 5 | Thrust ball bearing | T | Tapered roller bearing |
1.2 Bearing bore code
| Prefix | Bearing Basic Designation | Suffix | ||
| Bearing series code | Bearing bore code | |||
| Bearing type | Dimension series | |||
1.2.1 For the bearings with the inner diameter of 1 - 9 mm, it can be easily determined by the last digit.
- 608 = 8 mm
- 636 = 6 mm
- 129 = 9 mm
1.2.2 Bearings with a bore diameter of 10, 12, 15 or 17 mm have the following size code identifications:
- 00 designates aperture of 10 mm, for example 6300
- 01 designates aperture of 12 mm, for example 6201
- 02 designates aperture of 15 mm, for example 6002
- 03 designates aperture of 17 mm, for example 6203
1.2.3 For the bearing with a bore diameter of 20-480 mm, the inside diameter is 5 times the last two digits. For example:
- 6205 is 5 x 5 = 25 mm
- 6212 is 12 x 5 = 60 mm
1.2.4 For bearings with a bore diameter ≥ 500 mm, the bore diameter is generally given in millimetres. The size identification is separated from the rest of the bearing designation by an oblique stroke, e.g. 511/530 (d = 530 mm).
2, Prefixes
Prefixes are mainly used to identify components of a bearing. They can also identify bearing variants.
3, Bearing suffix codes
Bearing suffixes are used to identify structural modifications. Specifically, the bearing suffixes provide information about the:
- Internal design
- Seal
- Cage type
- Tolerances
- Internal clearance
- Lubricant used
- External design