Page 687 - Rollingbearings

Temperature limits
Comparative load Temperature
ratings for double limits

row tapered roller
bearings The permissible operating temperature for
tapered roller bearings can be limited by:
For rolling mill applications, load ratings are
not necessarily calculated according to • the dimensional stability of the bearing
ISO 281 Instead, they are often calculated rings and rollers
by a different method based on a rating life • the cages
of 90 million revolutions (500 r/min for • the seals
3 000 operating hours) Therefore, for • the lubricant
double row tapered roller bearings these
comparative load ratings are provided in the Where temperatures outside the permissible
product tables because a direct comparison range are expected, contact SKF
between the comparative and ISO load rat-
ings is not possible, even if the comparative Bearing rings and rollers
ratings are converted for 1 million revolu-
tions (ISO life deinition) SKF single row and matched tapered roller
These comparative load ratings may not bearings are heat stabilized up to:
be used to calculate an ISO rating life They
may only be used together with the compara- • D ≤ 160 mm → 120 °C (250 °F)
tive rating life and equivalent load equations • D > 160 mm → 150 °C (300 °F)
speciied as follows:
SKF double row tapered roller bearings are
q C 10/3
w
F
L F10 =90 ––– heat stabilized up to 150 °C (300 °F)
< P ⎠
F
or Seals
q C 10/3 q w The permissible operating temperature for
w
F
L F10h = ––– 1 500 000
JJJJ
< P ⎠ < n ⎠ seals depends on the seal material:
F
8
where • HNBR: –40 to +150 °C (–40 to +300 °F)
L F10 = comparative rating life [million • FKM: –30 to +200 °C (–20 to +390 °F)
revolutions]
L F10h = comparative rating life [operating Typically, temperature peaks are at the seal
hours] lip
C = comparative dynamic load rating to
F
give a rating life of 90 million revolu- Cages
tions [kN] (product tables,
page 762) Steel or PEEK cages can be used at the same
P = comparative equivalent dynamic operating temperatures as the bearing rings
F
bearing load [kN] (table 8, and rollers For temperature limits of cages
page 686) made of other polymer materials, refer to
n = constant rotational speed [r/min] Polymer cages, page 188.
Lubricants

For temperature limits of SKF greases, refer
to Selecting a suitable SKF grease, page 116
When using lubricants not supplied by
SKF, temperature limits should be evaluated
according to the SKF trafic light concept
(page 117)

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