SKF - Rolling Bearings

7 Tapered roller bearings
Temperature limits
The permissible operating temperature for
tapered roller bearings can be limited by:
• the dimensional stability of the bearing
rings and rollers
• the cage
• the lubricant
When temperatures outside the permissible
range are expected, contact the SKF application
engineering service.
Bearing rings and rollers
SKF tapered roller bearings undergo a special
heat treatment. The bearings are heat sta bilized
up to:
• D ≤ 160 mm † 120 °C (250 °F)
• D > 160 mm † 150 °C (300 °F)
Cages
Steel or PEEK cages can be used at the same
operating temperatures as the bearing rings
and rollers. For temperature limits of cages
made of other polymer materials, refer to Cage
materials († page 152).
Lubricants
Temperature limits for SKF greases are provided
under Lubrication († page 239). When
using lubricants not supplied by SKF, the temperature
limits should be evaluated according
to the SKF traffic light concept († page 244).
Design of bearing
arrangements
Single row tapered roller bearings must either
be used with a second bearing or as a matched
pair († fig. 10). The bearings must be
adjusted against each other until the requisite
clearance or preload is obtained († Bearing
preload, page 214). To maximize bearing performance
and operational reliability, the
appropriate clearance or preload must be
selected and then applied during the mounting
process. When the operating clearance in a
bearing arrangement is too large, the load
carrying cap acity of both bearings cannot be
fully utilized. Excessive preload increases friction,
which increases the amount of frictional
heat and reduces bearing service life.
Fits for inch bearings
In contrast to metric bearings, which are
machined to a minus tolerance, inch bearings
are machined to a plus tolerance († table 9,
page 143). Therefore, the deviations for shaft
and housing diameters for metric bearings are
not applicable. Suitable fits for inch bearings
can be obtained from the recommended fits
for metric bearings. Tables 6 and 7
(† pages 818 and 819) provide the shaft and
housing fits for inch tapered roller bearings
that are valid for Normal tolerance bearings in
typical applications.
Permissible speed
The permissible speed can be estimated using
the speed ratings listed in the product tables
and applying the information provided under
Speeds († page 117).
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