Sealed bearings equipped with contact seals on both sides (fig. 5) are available:
-
in the 22 and 23 series
-
with bore diameter 10 ≤ d ≤ 70 mm
-
with seals made of sheet steel reinforced NBR (oil and wear-resistant, designation suffix 2RS1)
Permissible angular misalignment of sealed bearings is slightly reduced compared to open design bearings.
Greases for capped bearings
Bearings sealed on both sides are lubricated for the life of the bearing and are virtually maintenance-free. They are filled with one of the following standard greases, which have good corrosion-inhibiting properties (table 1):
-
D ≤ 62 → MT47 grease
-
D > 62 → MT33 grease
Grease life for capped bearings
-
is presented as L10, i.e. the time period at the end of which 90% of the bearings are still reliably lubricated
-
depends on the operating temperature and the speed factor (diagram 1)
The grease life specified in
diagram 1 is valid for the following combination of operating conditions:
-
horizontal shaft
-
inner ring rotation
-
light load (P ≤ 0,05 C)
-
operating temperature within the green temperature zone of the grease (table 1)
-
stationary machine
-
low vibration levels
Where the operating conditions differ, the grease life obtained from the diagram should be adjusted:
-
vertical shafts → 50% of the obtained value
-
heavier loads (P > 0,05 C) → apply reduction factor (table 2)
When sealed bearings must operate under certain extreme conditions, such as very high speeds or high temperatures, grease may appear on the capping diameter. For bearing arrangements where this should be detrimental, appropriate actions could be taken. For additional information, contact the SKF application engineering service.