SKF - Rolling Bearings

1 Deep groove ball bearings
Sealing solutions
SKF supplies the most popular sizes of deep
groove ball bearings capped with a seal or
shield on one or both sides. Selection guidelines
for different sealing solutions under various
operating conditions are listed in table 2.
However, these guidelines cannot substitute
for testing a seal in its application. For additional
information, refer to Sealing solutions
(† page 226).
ICOS oil sealed bearing units, which are
standard deep groove ball bearings with an
integrated radial shaft seal, are also available.
When capped bearings must operate under
certain extreme conditions, such as very high
speeds or high temperatures, grease may leak
at the inner ring. For bearing arrangements
where this would be detrimental, special
design steps must be undertaken. For additional
information, contact the SKF application
engineering service.
Bearings capped on both sides are lubricated
for the life of the bearing and should not
be washed or relubricated. They are filled with
the appropriate amount of a high-quality
grease under clean conditions. The bearings
are considered maintenance-free. If they are
to be hot mounted, an induction heater should
be used.
SKF does not recommend heating capped
bearings above 80 °C (175 °F). 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.
The seals, which are fitted in a recess on the
outer ring, make good, positive contact with
the recess, without deforming the outer ring
(† figs. 7 to 9, pages 301 to 303).
Table 2
Selection guidelines for SKF sealing solutions
Requirement Shields Non-contact
seals
Low-friction
seals
Contact seals
Z, ZS RZ RSL RSH RS1
Low friction +++ +++ ++ L L
High speed +++ +++ +++ L L
Grease retention L + +++ +++ ++
Dust exclusion L + ++ +++ +++
Water exclusion
static – – L +++ ++
dynamic – – L + +
high pressure – – L +++ L
Symbols: +++ = best ++ = very good + = good L = fair – = not recommended
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