SKF - Rolling Bearings

Deep groove ball bearings for extreme temperatures
Deep groove ball bearings for
extreme temperatures
SKF deep groove ball bearings for extreme
temperatures correspond in design to standard
single row deep groove ball bearings of the
same size. They have no filling slots and can
accommodate normal axial loads in addition to
radial loads. The radial internal clearance is a
multiple of C5 to prevent the bearings from
seizing, even when they cool rapidly. All surfaces
of the bearing and shields are manganese
phosphated to enhance adhesion of the
lubricant to the metal and provide additional
protection against corrosion.
SKF deep groove ball bearings for extreme
temperatures are available in the variants
listed in table 1. Typically, the bearings have a
shield on both sides (designation suffix 2Z).
The VA201 variant is also available as an open
bearing († fig. 3, page 1172).
Shields prevent the ingress of solid contaminants
into the bearing. The shields on a
2Z/VA201 bearing enable the bearing to be
filled with twice the amount of polyalkylene
glycol/graphite lubricant found in an open
VA201 bearing.
Table 1
Extreme temperature variants for deep groove ball bearings and Y-bearings
Characteristics
VA201 VA208 VA228
• Bearing with a riveted stamped
steel cage
• Filled with a polyalkylene glycol/
graphite mixture for lubrication
• Running-in period required to
distribute the lubricant within
the bearing for applications that
stand idle for an extended
period
• Not for wet or humid
environments
• Bearing with a segmented cage
made of graphite
• Dry lubricant: minute amounts
of graphite powder released
from the cage lubricate the
bearing.
• A shield on both sides of the
bearing guides the cage
segments.
• Even at the upper temperature
limits, the segmented graphite
cage does not release harmful
vapours.
• Should not be used for
applications where the direction
of rotation changes frequently.
• Bearing with a coronet cage
made of graphite
• Dry lubricant: minute amounts
of graphite powder released
from the cage lubricate the
bearing.
• A shield on both sides of the
bearing guides the cage.
• Even at the upper temperature
limits, the graphite cage does
not release harmful vapours.
Temperature –30 to +250 °C –150 to +350 °C –150 to +350 °C
limits 1) (–20 to +480 °F) (–240 to +660 °F) (–240 to +660 °F)
Limiting speed 2)
[r/min]
9 000
———
4 500
9 000
———
———
d m d m dm
d m = bearing mean diameter [mm]
= 0,5 (d + D)
1) VA201 bearings operating below 200 °C (390 °F) at speeds below 25% of limiting speed require a running-in procedure. These
bearings should be heated to 200 °C (390 °F) for at least 48 hours.
2) When higher speeds are expected, consider using SKF DryLube bearings († page 1191) or contact the SKF application
engineering service.
15B
1171