The basic code of a bearing is composed of the bearing type code, the dimension series code, and the inner diameter code.  

For example: For 6201, 6 represents the type code; 2 represents the dimension series code; 01 represents the inner diameter code. 1. Bearing Type Code The bearing type code is represented by numbers or letters, as shown in the following table:

2. Dimension Series Code

The dimension series code of a bearing is composed of the width (height) series code and the diameter series code of the bearing.

The diameter series refers to the outer diameter dimension series corresponding to the same inner diameter of the bearing. There are diameter series such as 7, 8, 9, 0, 1, 2, 3, 4, 5, etc., with the outer diameter dimensions increasing sequentially.

The width series refers to the width dimension series corresponding to the same diameter series of the bearing. There are width series such as 8, 0, 1, 2, 3, 4, 5, 6, etc., with the width dimensions increasing sequentially.

For thrust bearings, the height series corresponds to the width series of radial bearings. There are four height series such as 7, 9, 1, 2, etc., with the height dimensions increasing sequentially.

3. Inner Diameter Code

See the following table:  

The Meaning of Prefixes in SKF Bearing Supplementary Codes

The prefixes of SKF bearing models are mainly used to indicate the components of SKF bearings. To avoid confusion with other models, they are usually placed before the entire SKF bearing model.

· GS: The housing ring of a cylindrical roller thrust bearing

· K: Cylindrical roller-cage thrust assembly

· K-: The inner ring with roller-cage assembly (CONE) or the outer ring (CUP) of an inch tapered roller bearing in the ABMA standard series

· L: The inner ring or the outer ring of a separable bearing

· R: The inner ring or the outer ring with roller-cage assembly of a separable bearing

· W: Stainless steel deep groove ball bearing

· WS: The shaft ring of a cylindrical roller thrust bearing

· ZE: Bearings for electrically controlled installation methods

Note: For SKF tapered roller bearings, especially inch bearings, the inner ring with roller-cage assembly is generally called a CONE, and the outer ring is called a CUP.

The Meaning of Suffixes in SKF Bearing Supplementary Codes (Suffix Codes)

The suffixes of SKF bearing models are used to indicate variants with different structures and/or other characteristics compared to the basic design. When it is necessary to indicate more than one bearing characteristic, the suffixes are regularly divided into several groups.

The following lists the more commonly used suffixes, but it should be noted that not all variants can be listed here (for specific types of suffixes, you can refer to other relevant information).

· A: An internally designed bearing that has been improved or slightly modified. The external dimensions are the same. Usually, it has different meanings for different types or series of SKF bearings. For example: 4210 A: indicates a double-row deep groove ball bearing without a ball filling notch; 3220 A indicates a double-row angular contact ball bearing with a contact angle of 30°.

· AC: A single-row angular contact ball bearing with a contact angle of 25°

· ADA: The snap groove on the outer ring has been improved, and the split inner ring is fixed by a retaining ring.

B: An internally designed bearing that has been improved or slightly modified, with the same external dimensions. Usually, it has different meanings for different types or series of SKF bearings. For example: 7224 B indicates a single-row angular contact ball bearing with a contact angle of 40°; 32210 B indicates a tapered roller bearing with a larger contact angle.

· Bxx(x): A combination of B and a two-digit or three-digit number, used to indicate some variants for which there is no suitable suffix. For example: B20: Narrowed width tolerance.

· C: An internally designed bearing that has been improved or slightly modified. The external dimensions are the same. Usually, it has different meanings for different types or series of bearings. For example: 21306 C indicates a spherical roller bearing with two window-type stamped steel cages, no rib on the inner ring, and a guide ring guided by the inner ring.

· CA: 1. Type C spherical roller bearing with a fork-type machined brass cage, ribs on both sides of the inner ring, and a guide ring guided by the inner ring; 2. General matching bearings. When arranged back-to-back or face-to-face, the axial clearance is smaller than that of the normal group (CB).

· CAC: Type CA spherical roller bearing with improved roller guidance.

· CB: 1. General matching bearings. When arranged back-to-back or face-to-face, the axial clearance is in the normal group; 2. Double-row angular contact ball bearings with specific axial clearance.

· CC: 1. Type C spherical roller bearing with improved roller guidance; 2. General matching bearings. When arranged back-to-back or face-to-face, the axial clearance is larger than that of the normal group (CB).

· CLN: Tapered roller bearings with narrowed tolerance zones for the width of the rings and the total width, conforming to the ISO tolerance class 6X.

· CL0: Precision conforming to the ANSI/ABMA 19.2:1994 standard tolerance class 0, used for inch tapered roller bearings.

· CL00: Precision conforming to the ANSI/ABMA 19.2:1994 standard tolerance class 00, used for inch tapered roller bearings.

· CL3: Precision conforming to the ANSI/ABMA 19.2:1994 standard tolerance class 3, used for inch tapered roller bearings.

· CL7C: Used for tapered roller bearings, with special friction characteristics and higher rotational accuracy.

· CN: Normal group radial clearance; usually only used in combination with the following letters to indicate a narrower or offset clearance range.

o CNH: Narrowed clearance range, equivalent to the upper half of the normal group clearance range.

o CNM: Narrowed clearance range, equivalent to half of the normal group clearance range.

o CNL: Narrowed clearance range, equivalent to the lower half of the normal group clearance range.

o CNP: Offset clearance range, equivalent to the combination of the upper half of the normal group clearance range and the lower half of the C3 clearance range.

o CNR: Cylindrical roller bearings with normal group clearance conforming to DIN 620-4:1982.

o The above letters H, M, L, and P are also applicable to combining with the following clearance groups to form corresponding meanings: C2, C3, C4, and C5, such as C2H.

· CV: Improved internal design, full complement cylindrical roller bearing.

· CS: Nitrile butadiene rubber (NBR) contact seal with a steel skeleton on one side of the bearing.

· CS2: Fluororubber (FPM) contact seal with a steel skeleton on one side of the bearing.

· CS5: Hydrogenated nitrile butadiene rubber (HNBR) contact seal with a steel skeleton on one side of the bearing.

· 2CS: Nitrile butadiene rubber (NBR) contact seals with a steel skeleton on both sides of the bearing.

· 2CS2: Fluororubber (FPM) contact seals with a steel skeleton on both sides of the bearing.

· 2CS5: Hydrogenated nitrile butadiene rubber (HNBR) contact seals with a steel skeleton on both sides of the bearing.

· C1: Radial clearance smaller than C2.

· C2: Radial clearance smaller than the normal group (CN).

· C3: Radial clearance larger than the normal group (CN).

· C4: Radial clearance larger than C3.

· C5: Radial clearance larger than C4.

· C02: Narrowed inner ring rotational accuracy tolerance.

· C04: Narrowed outer ring rotational accuracy tolerance.

· C08: C02 + C04.

· C083: C02 + C04 + C3.

· C10: Narrowed inner and outer diameter tolerances.

· D: An internally designed bearing that has been improved or slightly modified, with the same external dimensions. Usually, it has different meanings for different types or series of bearings. For example: 3310 D indicates a double-row angular contact ball bearing with a split inner ring.

DA: The snap groove on the outer ring has been improved, and the split inner ring is fixed by a retaining ring.

DB: Two single-row deep groove ball bearings (1), single-row angular contact ball bearings (2), or single-row tapered roller bearings (3) paired back-to-back. The letter following DB indicates the magnitude of the axial clearance or axial preload of the paired bearings before installation.

o A: Light preload (2).

o B: Medium preload (2).

o C: Heavy preload (2).

o CA: Small axial clearance (1, 2).

o CB: Normal axial clearance (1, 2).

o CC: Large axial clearance (1, 2).

o C: Special axial clearance, plus a number in um to indicate (3).

o GA: Light preload (1).

o GB: Medium preload (1).

o G: Special preload load, plus a number in daN to indicate (3).

o For paired tapered roller bearings, there may be a two-digit number between DB and C or G to indicate the design and configuration of the spacer, such as 330224 J2 / DB31C250.

DF: Two single-row deep groove ball bearings, single-row angular contact ball bearings, or single-row tapered roller bearings paired face-to-face. The meaning indicated by the letter following DF is the same as that of DB.

DT: Two single-row deep groove ball bearings, single-row angular contact ball bearings, or single-row tapered roller bearings paired in tandem. Tandem matching installation; for paired tapered roller bearings, there may be a two-digit number after DT to indicate the design and configuration of the spacer.

E: An internally designed bearing that has been improved or slightly modified, with the same external dimensions. Usually, it has different meanings for different types or series of bearings. For example: 7212 BE indicates a single-row angular contact ball bearing with an optimized internal design and a contact angle of 40°.

EC: Single-row cylindrical roller bearing with an optimized internal design, equipped with more and/or larger rollers, and improved contact between the roller end faces and the ribs.

ECA: Type CA spherical roller bearing with an enhanced roller set.

ECAC: Type CAC spherical roller bearing with an enhanced roller set.

F: Machined steel or special cast iron cage, guided by the rolling elements. There may be a number after F to indicate different designs or materials, such as F1.

· FA: Machined steel or special cast iron cage, guided by the outer ring.

· FB: Machined steel or special cast iron cage, guided by the inner ring.

· G: General matching single-row angular contact ball bearings. Two bearings paired back-to-back or face-to-face have a certain axial clearance before installation.

· G..: Used to describe the grease used in the bearing. The second letter indicates the operating temperature range of the grease, and the third letter indicates a specific actual grease. The meanings of the second letter are as follows:

o E: Extreme pressure grease.

o F: Food-compatible grease.

o H, J: High-temperature grease, -20 to +130°C.

o L: Low-temperature grease, -50 to +80°C.

o M: Medium-temperature grease, -30 to +110°C.

o W, X: Low/high-temperature grease, -40 to +140°C.

o The digits after the three-letter grease code indicate the grease filling amount different from the standard: 1, 2, and 3 indicate less filling than the standard, and 4 to 9 indicate more filling than the standard. For example: GEA indicates extreme pressure grease with the standard filling amount; GLB2 indicates low-temperature grease with a filling amount of 15% to 25% of the free space inside the bearing.

· GA: General matching bearings with light preload when arranged back-to-back or face-to-face.

· GB: General matching bearings with medium preload when arranged back-to-back or face-to-face.

· GC: General matching bearings with heavy preload when arranged back-to-back or face-to-face.

· GJN: Polyurea soap grease, NLGI consistency 2, operating temperature range -30 to +150°C.

· H: Case-hardened snap-type stamped steel cage.

· HA: Case-hardened bearing or bearing component. The number following HA indicates the specific part.