SKF - Spherical Plain Bearings and Rod Ends

Angular contact spherical plain bearings
When the resultant load († fig. 9) is constant
in magnitude, then use
Angular contact spherical plain bearing under
combined load
Fig. 9
1
P = y F r
where
P = equivalent dynamic bearing load [kN]
F r = radial component of the load [kN]
y = load factor that depends on the ratio of the
axial to the radial load F a /F r († diagram 3)
Thrust spherical plain bearings
Thrust spherical plain bearings can accommodate
a radial load F r in addition to an axial load
F a († fig. 10). However, the radial load must
not exceed 50% of the simultaneously acting
axial load. When the resultant load is constant in
magnitude, then use
P = y F a
Thrust spherical plain bearing under combined load
Fig. 10
where
P = equivalent dynamic bearing load [kN]
F a = axial component of the load [kN]
y = load factor depending on the ratio of the
radial to the axial load F r /F a
(† diagram 4)
Equivalent static bearing load
If spherical plain bearings and rod ends are subjected
to static loads, or very slight alignment
movements, then the permissible load is not
limited by wear, but by the strength of the sliding
contact layer or the strength of the rod end
housing.
If the actual load is a combined load, then
an equivalent static bearing load must be calculated.
For radial and angular contact spherical
plain bearings, it can be calculated using
P 0 = y F r
For thrust spherical plain bearings, it can be
calculated using
P 0 = y F a
where
P 0 = equivalent static bearing load [kN]
F r = radial component of the load [kN]
F a = axial component of the load [kN]
y = load factor that depends on the ratio of the
axial to the radial load F a /F r
– for radial bearings requiring maintenance
(† diagram 1)
– for maintenance-free radial bearings
(† diagram 2)
– for angular contact spherical plain
bearings († diagram 3)
and load factor that depends on the ratio of
the radial to the axial load F r /F a
– for thrust spherical plain bearings
(† diagram 4)
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