Lubrication

Grease types

SKF ConCentra roller bearing units, excluding the relubrication-free variant, are filled with premium grease that contains EP additives. The grease is mineral oil based with a lithium thickener and consistency of 2 on the NLGI scale.
Relubrication-free SKF ConCentra roller bearing units are filled with a premium long life grease. This grease has a semi-synthetic base oil, lithium thickener and consistency of 2–3 on the NLGI scale. The technical specifications of both greases are listed in the table.
The initial grease fill at the factory fills the bearing completely. The free space in the housing is partially filled with grease as follows:
  • 60 to 80%, for the relubrication-free variant of SKF ConCentra roller bearing units in the SYNT series
  • 30 to 50%, for all other roller bearing units

Relubrication

All plummer block units have a lubrication hole with a 1/8-27 NPSF thread. They are provided, as standard, with a grease fitting AH 1/8-27 PTF, except for the relubrication-free variant of SKF ConCentra roller bearing units, which has the lubrication hole plugged.
Additional information is provided in the section Relubrication.

Grease life for the relubrication-free variant of SKF ConCentra units

The grease used in SKF relubrication-free roller bearing units can adequately lubricate the bearings throughout their service life provided the unit is suitable for the operating conditions. The relationship between operating conditions and grease service life shown in the diagram 1 is a function of:
  • the operating temperature, °C
  • the speed factor A = n dm

where
A=speed factor, mm/min
n=rotational speed, r/min
dm=bearing mean diameter, mm (table)
Provided the operating range of the bearing unit falls within the shaded area of the diagram, the bearing unit can attain a grease life L50h = 100 000 hours or more.
For additional information about the relubrication-free variant of SKF ConCentra roller bearing units, refer to the section Variants.