Page 679 - SKF-bearing-housings

Lubrication

Lubrication For additional information about permis-
sible temperatures of rolling bearing greases
SKF ConCentra roller bearing units are (the SKF traffic light concept), refer to the
intended for grease lubrication. information available online at skf.com/
bearings.
Initial grease fill
SKF ConCentra roller bearing units in the Relubrication
general, high-speed and extreme environment SKF ConCentra roller bearing units are typ-
variants are filled with a mineral oil based lith- ically relubricated in order to realize maximum
ium grease. The initial grease fill at the factory service life. All bearing units have a lubrication
fills the bearing completely, and 30 to 50% of hole with a 1/8-27 NPSF thread. They are
the free space in the housing. provided standard with a grease fitting
Relubrication-free bearing units are filled AH 1/8-27 PTF, except for the relubrication-
with a semi-synthetic oil based lithium grease. free variant, which has the lubrication hole
The initial grease fill at the factory fills the plugged.
bearing completely, and 60 to 80% of the free
space in the housing.
The technical specifications of both greases
are provided in table 8.
For general, high-speed and extreme
variants, the grease provides reliable perfor-
mance when operating between 35 and 110 °C.
During start-up, temperatures down to –20 °C
are permissible. For short periods, tempera-
tures above 110 °C can be tolerated.
For the relubrication-free variant, the
grease provides reliable performance when
operating between 35 and 130 °C. During
start-up, temperatures down to –30 °C are
permissible. For short periods, temperatures
above 130 °C can be tolerated.

Table 8
Technical specifications for the greases in SKF ConCentra roller bearing units
Housing variant Temperature Thickener Base oil type NLGI Base oil viscosity [mm 2 /s]
range consistency at 40 °C at 100 °C
class (105 °F) (210 °F)
General, high-speed and –20 to 110 °C Lithium Mineral 2 200 13
extreme temperature (–5 to 230 °F) soap
Relubrication-free –30 to 130 °C Lithium Semi- 2–3 41,9 7,5
(–20 to 250 °F) soap synthetic

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