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9 INTERNAL SELF-ALIGNING BALL & ROLLER BEARING UNITS

6. Limiting speed & lubrication

Approximate limiting speed as excessive lubricant in the housing causes churning
which generates heat and can do the bearing serious
Although the limiting speed of a bearing is influenced by
damage. Depending on the type of service, the cap or
its type, size, cage construction, lubrication method, load
cover should be removed, cleaned of old grease and
and other factors, it is customary to establish limiting
sufficient fresh grease added at suitable intervals..The
speed values as a guide to lubricant selection. The
fitting of grease nipples to housings can be a disadvan-
allowable speeds listed in Section 9 for Grease and Oil
tage if the bearings are operating at high speeds. Refer to
Lubrication are based on Normal Operating Conditions,
limiting speeds of rotation in ‘Calculation’ Section.
correctly installed, using suitable lubricants with ad-
equate supply and proper maintenance. Also, these
values are based on Normal Load Conditions. Figure 5. Load Factor fL
(P≤0.09C, Fa/Fr≤0.3)
When the radial load is greater than C/1 5, the limiting
speed should be reduced by (FL) “Load Factor” shown in 1.0
Figure 5. If axial forces are involved in the applied load 0.9
0.8
then the limiting speed should be approximately 80% of 0.7
the value shown. When it is necessary for a bearing to F L 0.6
operate at higher speeds than indicated, it is advisable to 0.5
0.4
provide a circulating or a pressure fed oil system.

Lubrication 4 5 6 7 8 9 10 11 12 13 14 15
C/P
Oil: The oil used for bearing lubrication should be high
quality, oxidation and rust resistant petroleum oil. The oil Table 15. Standard Cage of Spherical Roller Bearing
should be at least 100 S.U.S. Bearing speeds, loads,
1 L 3 F 1 F
temperature and method of lubrication may influence the J G I H H N E T O I S N A E L D C A R B O N L E E T S
B A E N I R G
required viscosity. S S E I R E L E E T S E T A L P B R A S S R F C - E E U N I T T G F O R M A C N I H E
P ( R S E S ) D E C A N I T S G L E E T S C O N T S R U C O I T N
M ( A C N I H ) D E M ( A C N I H ) D E M ( A C N I H ) D E
Grease: Normally a lithium soap, NLGI grade No. 2 is
used. For slightly higher than normal temperatures a 9 3 2 0 8 - - 4 8
0 3 2 0 4 - 6 7 - 4 4 - 0 8
grade No. 3 can be used. If heavy loads or shock loading 0 4 2 8 4 - 6 7 - 2 5 - 0 8
exists, a No. 2 grease with an E.P. additive is recom- 1 3 2 4 3 - 8 6 - 6 3 - 2 7
1 4 2 4 4 - 8 6 - 8 4 - 2 7
mended. 2 2 2 6 3 - 4 6 - 8 3 - 8 6
2 3 2 8 1 - 4 6 - 0 2 - 8 6
Relubrication intervals 3 1 2 l l a
3 2 2 8 2 - 6 5 - 0 3 - 0 6
Bearings should be relubricated at regular intervals to
prevent damage. Exact relubricating intervals are difficult Lubrication grooves and holes
to predict because of differing environments. Consulta-
tion with a lubrication engineer may be necessary if Wog
unusual conditions exist. An oil bath may need to be doh
changed only once a year if the bearing operating
temperature is 50˚C–60˚C. Twice per year if the bearing
operating temperature is 80˚C–100˚C. Since grease life
will vary greating depending upon the grease utilized,
conservative intervals only can be estimated by nomo-
gram in Figure 6. Unusually dirty or wet conditions may Table 16. Dimensions
shorten grease life. Alternatively, a greater bearing U T I N m m
clearance or specially fabricated cage can enable higher O U T D I S E A I D M E T E R L I O G R O O V E W o g L I O H O L E od h
speeds to be obtained. For the bearings with pressed D
cage (J) the limiting speed should be reduced to 75% of B E A N I R G S E E I R S B E A N I R G S E E I R S
the value shown. O V E . R N I C . L 3 2 , 9 3 2 0 3 2 , 1 2 2 2 3 2 , 9 3 2 0 3 2 , 1 2 2 2
4 2 , 0 4 2 1 3 2 , 2 3 2 2 4 2 , 0 4 2 1 3 2 , 2 3 2 2
We recommend a lithium base grease which should be
3 5 1 4 0 0 2 1 2 1 6 6
packed well into the bearing, particularly around the cage 4 0 0 0 0 5 2 1 6 1 6 8
0 0 5 3 6 0 6 1 0 2 8 0 1
prior to bearing installation. It should be noted that 3 6 0 0 0 0 1 0 2 4 2 0 1 2 1
housing should be no more than one third full of grease 0 0 0 1 0 5 2 1 4 2 4 2 2 1 2 1
0 5 2 1 0 0 6 1 4 2 3 2 2 1 6 1
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