IBC Cylindrical Roller Bearings - Spekuma Kullager AB

10. Lubrication
Grease life
Greases age faster at higher operating temperatures than
at operating temperatures of 70 °C. If the working temperature
is higher than 70 °C as a result of own heat generation
or because of surrounding heat then the complete service
life of the bearing could depend on the service life of the
grease. We advise to compare the service life of the bearing
with the grease service life separately, as the bearing
service life is reduced if the thickness of the lubricant film is
not sufficient enough to prevent immediate metallic contact
between rolling elements, tracks and cage.
For more information on this subject also check picture
40-504, the example after picture 40-506 as well as diagramme
46-502.
applies to grease with
higher limited operating
temperature
Grease temperature value
applies to grease with
lower limited operating
temperature
Grease fatigue life 40-504
Corrections factors f p and f v for radial roller bearings 40-501
Lithium soap grease Li
With grease lubrication two values for f v are determined
out of the diagramme and are calculated as a ratio to each
other:
n max = f p • n r • f v base oil actual / f v base oil ISO VG 150 [3.3]
Rotational speed higher than reference rotational
speed
Rotational speed that is higher than the reference rotational
speed lead to excessive bearing temperatures, unless
corrective actions are undertaken such as heat absorbing
oil circulation lubrication, air-cooling or liquid cooling of the
inner ring and outer ring. High bearing temperatures reduce
the lubricant’s viscosity, thus perhaps preventing a
lubricant film that is sufficient for carrying loads. This results
in higher friction causing higher temperature, and, at
the same time reducing internal clearance. A seizure of
the bearings as a result of extended sliding friction, can result
from this.
Working temperature
Running time
Grease service life at certain temperatures 40-506
16 IBC WÄLZLAGER GMBH