With the exception of bearings designated with a BS2- prefix, the boundary dimensions of sealed spherical roller bearings are in accordance with ISO 15. Bearings with a BS2- prefix, for example BS2-2214-2CS, are based on 222 E or 223 E series bearings, but are slightly wider to accommodate the seals.
Sealed spherical roller bearings have the same features and internal design as basic design spherical roller bearings and are available with a cylindrical bore as standard. Some sizes are also available with a tapered bore or can be supplied with a tapered bore on request.
Sealed spherical roller bearings have a contact seal reinforced with a sheet steel insert, fitted on both sides. They can also be supplied with a seal on only one side. The bearings can be fitted with seals made of one of the following materials:
- NBR (designation suffix CS)
- HNBR (designation suffix CS5)
FKM (designation suffix CS2)
WARNINGSeals made of FKM (fluoro rubber) exposed to an open flame or temperatures above 300 °C (570 °F) are a health and environmental hazard! They remain dangerous even after they have cooled.
Read and follow the safety precautions under Seal materials.
The seals are fitted in a recess on the outer ring (fig. 1) and seal against the inner ring. On larger bearings, the seals are fixed by a retaining ring (fig. 2).
Sealed spherical roller bearings are supplied lubricated and should not be washed. For many application conditions, the bearings do not require relubrication and can be considered relubrication-free (→ Relubrication of sealed bearings).
SKF does not recommend heating sealed spherical roller bearings above 80 °C (175 °F) during the mounting process. However, if higher temperatures are necessary, make sure that the temperature does not exceed the permissible temperature of either the seal or grease, whichever is lowest.
Greases for sealed bearingsSealed spherical roller bearings are filled as standard with SKF LGEP 2 grease. Bearings filled with SKF LGHB 2 grease can be supplied on request. Technical specification of both greases are listed in table 1.
For additional information about greases, refer to Lubrication.
Relubrication of sealed bearingsSealed spherical roller bearings are designed to operate relubrication-free. For bearings lubricated with the standard grease LGEP 2 (designation suffix VT143), the lubrication-free operating conditions can be identified using diagram 1. The diagram is valid for bearings in light to normal load applications (P ≤ 0,1 C) on a horizontal shaft and a load ratio Fa/Fr ≤ e. For other operating conditions, the grease life can be estimated by multiplying the relubrication interval for open bearings (→ Relubrication) by a factor of 2,7.
In applications that have a life requirement outside the green area of diagram 1, the bearings may require relubrication.
A suitable grease quantity to relubricate sealed bearings can be obtained using
Gp = 0,0015 D B
Gp = 0,0015 D B
||grease quantity [g]
||bearing outside diameter [mm]
||bearing width [mm]
The grease should be applied slowly through the lubrication holes in the outer ring while the bearing is rotating, if possible, to avoid damaging the seals. SKF recommends relubricating with the same grease as the initial fill.