KNOWLEDGE

SKF Bearing Suffixes

SKF Bearing Suffixes

SKF Bearing Suffixes have different meanings. Common SKF bearing suffixes meaning is as below

(1) Internal design

Single row angular contact ball bearing

ACD: contact angle is 25 degree
B: The contact angle is 40 degree
CC: The contact angle is 12 degree
CD: The contact angle is 15 degree
BE: contact angle of 40 degree, with enlarged steel balls and glass fiber reinforced nylon 6.6 cage

Double row angular contact ball bearing – SKF Bearing Suffixes

A: Standard bearing design with outer diameter less than or equal to 90 mm, without a ball notch and a glass fiber reinforced nylon 6.6 cage.
E: There is a ball opening on one side of the bearing, which can hold more steel balls, so it has a higher radial and axial load capacity

Spherical roller bearing – SKF Bearing Suffixes

CAC, ECAC, CA, ECA: These are for large-size bearings, and the rollers are symmetrical.
CC, C, EC: The rollers of this type of bearing are symmetrical, and the inner ring has no ribs.

Cylindrical roller bearing – SKF Bearing Suffixes

B: Bearings use surface-treated rollers (full complement roller bearings).
B4: The surface of ring and rollers are treated (full complement roller bearing).
EC: The internal geometry of the bearing has been improved and has a higher load carrying capacity. The ribs and roller end faces have good contact and lubrication conditions, therefore bearing can withstand higher axial loads.

(2) External design

CA, CB, CC: Universal paired single row angular contact ball bearings, which can be installed in pairs (in series, face to face or back to back). When users arrange bearings back-to-back or face-to-face, the ratio of the internal clearance before axial installation to the normal value: small (CA), normal (CB), large (CC).
2F: Insert ball bearing (part of pillow block bearing) has dust retaining rings on both sides.
2FF: Insert ball bearing (part of pillow block bearing) has a combined dust retaining ring on both sides.
G: General matching single row angular contact ball bearings.
When users arrange bearings face to face or back to back, there is a certain preload in the bearing before installation.
GA: Face to face, back to back arrangement, there is a lighter preload in the bearing.
GB: Face to face, back to back arrangement, there is a medium preload in the bearing.
GC: Face to face, back to back arrangement, there is a heavier preload in the bearing.
K: conical hole, taper 1:12.
K30: Conical hole, taper 1:30.
LS: Bearing has a contact seal on one side, and the inner ring has no seal groove.
2LS: LS seals on both sides of the bearing.
N: There is a stop groove on the outer ring of the bearing.
NR: There is a stop groove and a stop ring on the outer ring of the bearing.
N2: There are two diametrically opposite notches on the outer ring chamfer.
PP: Bearing (support roller bearing, cam follower bearing) has contact seals on both sides.
RS: Bearing (needle roller bearing) has a synthetic rubber or polyurethane contact seal on one side.
RS1: Bearing has a steel lined synthetic rubber contact seal on one side.
2RS1: RS1 seals on both sides of the bearing.
2RS: Bearing (needle roller bearing) has RS seals on both sides.
RZ: Bearing has a low-friction seal with steel lined synthetic rubber on one side.
2RZ: RZ seals on both sides of the bearing.
X: Firstly, basic dimensions have been revised to meet ISO standards. Secondly, cylindrical rolling surface (support roller bearing, cam follower bearing).
Z: There is a dust cover on one side of the bearing (non-friction seal).
2Z: There are dust covers on both sides of the bearing.
ZN: Bearing has a dust cover on one side and a stop groove on the outer ring on the other side.
2ZN: Bearing has dust cover on both sides, and the outer ring has stop groove.
2NR: Same as -ZN, with a stop ring.
2ZNR: Same as -2ZN, with a stop ring.

(3) Cage

In order to indicate bearing cage guiding mode. Letter A or B can be added after the rear code of the cage. A indicates that the cage is guided by the outer ring, while B indicates that the cage is guided by the inner ring. The cage without indication is guided by rolling elements.
F: Steel or special cast iron solid cage.
J: Steel plate stamping forming cage.
M: Light alloy solid cage.
MP: Brass solid cage.
P: Glass fiber nylon 6.6 injection molded cage.
TN: Engineering plastic injection molding cage.
Y: Copper plate stamping forming cage.
V: Full roller bearing (without cage).
VH: Full complement bearing (cylindrical roller bearing) composed of non-separable roller assemblies.

(4) Other characteristics

1) Tolerance class – SKF Bearing Suffixes

/CLN: Equivalent to ISO tolerance grade 6X, used for metric tapered roller bearings (width tolerance is reduced).
/CL0: Equivalent to ISO0 tolerance, used for inch tapered roller bearings.
/CL3: Equivalent to ISO3 tolerance, used for inch tapered roller bearings.
/CL7A: Tapered roller bearing that meets the standard of differential bearing configuration.
/CL7C: Tapered roller bearings that meet the special standards of differential bearing configuration.
/P4: The size and rotation accuracy meet the ISO4 tolerance (precision than P5).
/P4A: The dimensional accuracy meets the ISO4 tolerance, and the rotation accuracy is equivalent to the AFBMA standard ABEC9.
/P5: Dimensional rotation accuracy meets ISO5 tolerance (accuracy higher than P6).
/PA9A: The size and rotation accuracy are equivalent to ABEC9 level of AFBMA standard.
/PA9B: The dimensional accuracy is equivalent to ABEC9 of the AFBMA standard, and the rotation accuracy is higher than that of PA9A.
/SP: The dimensional accuracy is about P5, and the rotation accuracy is about P4.
/UP: The dimensional accuracy is about P4, and the rotation accuracy is higher than P4.

2) Bearing clearance

/C1: The clearance meets the standard requirement of 1 group, and the clearance is less than 2 groups.
/C2: The clearance conforms to the 2 groups specified by the standard, and the clearance is less than 0 group.
/C0: The clearance complies with the 0 group stipulated by the standard, and the code is omitted and not indicated.
/C3: The clearance meets the 3 groups specified by the standard, and the clearance is greater than 0 group.
/C4: The clearance conforms to the 4 groups specified by the standard, and the clearance is greater than 3 groups.
/C5: The clearance conforms to the 5 groups specified by the standard, and the clearance is greater than 4 groups.
When clearance code is combined with the bearing tolerance class code P4, P5 or P6, the clearance code C can be omitted.
For example: P6+C2=P62

3) Special technical requirements

/Q: The best internal geometry and surface roughness (for tapered roller bearings).
/Q66: The vibration level is less than the ordinary standard, and the vibration peak is less than the ordinary standard.
/QE5: Meet the special standards for motors, size and rotation accuracy up to P6. Very low noise.
/QE6: Comply with motor standards, low noise.

4) Bearing configuration

/DB: Two pairable single row deep groove ball bearings, single row angular contact ball bearings or single row tapered roller bearings are installed in pairs in a back-to-back manner. The number after DB indicates the axial clearance or the preload during installation.
A: Light preload (angular contact ball bearing).
B: The preload is larger than A (angular contact ball bearing).
C: The preload is larger than B (Angular contact ball bearing).
CA: Small internal clearance (deep groove or angular contact ball bearings).
CB: Larger internal clearance than CA (deep groove or angular contact ball bearings).
CC: The internal clearance is larger than CB (deep groove ball bearing).
CG: “Zero” clearance (tapered roller bearing).
C…: Special axial internal clearance The number behind CC indicates the axial clearance.
GA: Lighter preload (deep groove ball bearing).
GB: Preload is greater than CA (deep groove ball bearing).
G…: Special preload (the number after G indicates the size of the preload).
/DF: Two paired single row deep groove ball bearings, single row angular contact ball bearings or single row tapered roller bearings arranged in a face-to-face manner.
DF can be followed by the same letter as DB.
/DT: Two paired deep groove ball bearings arranged in series, single row angular contact ball bearings or single row tapered roller bearings.

5) Heat treatment

The dimensions of the inner and outer rings of the bearing have been stabilized and can operate at the following temperatures:
/S0: Up to 150 degrees Celsius.
/S1: Up to 200 degrees Celsius.
/S2: Up to 250 degrees Celsius.
/S3: Up to 300 degrees Celsius.
/S4: Up to 350 degrees Celsius.

6) Replenishment of lubricant

/W: Cannot add lubricating oil (no lubricating oil groove and oil hole).
/W20: There are three lubricating holes in the outer ring of the bearing.
/W33: There are lubricating oil grooves and three oil holes on the outer ring of the bearing.
/W33X: There are lubricating oil grooves and six oil holes in the outer ring of the bearing.

7) Lubricants

We use post code to identify the type of grease filled in the bearing consists of a letter group and two numbers.
The letter represents the temperature range, and the last two numbers represent the actual grease used. Common letter groups are as follows:
/HT: High temperature grease (-20 degrees Celsius to +130 degrees Celsius).
/LHT: Low/high temperature grease (-40 degrees Celsius to +140 degrees Celsius).
/LT: Low temperature grease (-50 degrees Celsius to +80 degrees Celsius).
/MT: Medium temperature grease (-30 degrees Celsius to 110 degrees Celsius).
The MT postcode indicates that the specific bearing uses non-standard grease. When the amount of grease in the bearing is different from the standard filling amount (25%~30% of the free space inside the bearing), it is identified by an additional letter:
A: The amount of grease is less than the standard amount.
B: The amount of grease is greater than the standard amount.
C: The amount of grease is greater than B.

8) Other characteristics

Letter V and another letter (such as VA) are combined with three numbers to identify variants of the standard design that cannot be expressed by other existing postcodes.
For example:
/VA201: Kiln car bearing.
/VA301: Cylindrical roller bearings for traction motors

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