Page 852 - Rollingbearings

10 CARB toroidal roller bearings
Temperature Cages Lubricants
Steel or brass cages can be used at the same Temperature limits for greases used in
limits operating temperatures as the bearing rings. sealed CARB bearings are provided in
For temperature limits of polymer cages, table 1, page 845 For temperature limits of
refer to Polymer cages, page 188. other SKF greases, refer to Selecting a suit-
The permissible operating temperature for able SKF grease, page 116
CARB bearings can be limited by: Seals When using lubricants not supplied by
SKF, temperature limits should be evaluated
• the dimensional stability of the bearing The permissible operating temperature for according to the SKF trafic light concept
rings seals depends on the seal material: (page 117)
• the cage
• the seals • HNBR: –40 to +150 °C (–40 to +300 °F)
• the lubricant • NBR: –40 to +90 °C (–40 to +195 °F)
Temperatures up to 120 °C (250 °F) can Permissible speed
Where temperatures outside the permissible be tolerated for brief periods
range are expected, contact SKF
Typically, temperature peaks are at the seal The speed ratings in the product table
Bearing rings lip indicate:

The rings of CARB bearings are heat stabil- • the reference speed, which enables a
ized up to 200 °C (390 °F). quick assessment of the speed capabilities
from a thermal frame of reference
• the limiting speed, which is a mechanical
limit that should not be exceeded unless
the bearing design and the application are
Fig. 11 adapted for higher speeds
Permissible axial displacement
For additional information, refer to Operating
temperature and speed, page 130
s 2
s 1 s 1

Design

considerations

Open bearing Open full complement Sealed full complement
with a cage bearing bearing
Verification of axial
displacement
Diagram 1
10 The clearance window for a C 3052 CARB bearing with a maximum operating The actual internal clearance can limit the
possible axial displacement Misalignment
clearance of 0,150 mm
reduces the possible axial displacement
Therefore, the actual axial displacement
Radial clearance [mm] should be veriied
0,175
1 Determine the required axial
0,150
Clearance reduction displacement
0,125 ≈ 0,039 mm
– Thermal expansion of the shaft can be
0,100 estimated using
0,075 s req = α L ΔT
0,050 – Where additional effects need to be
0,025 considered, advanced simulation or
tests may be required
0
–14 –12 –10 –8 –6 –4 –2 0 2 4 6 8 10 12 14
Axial displacement [mm]

850