Page 144 - Rollingbearings

B.6 Bearing interfaces
Conditions of rotation • Stationary loads should be able to move axially in its hous-
These loads occur where both the bearing ing, a loose it must be used However, a
Conditions of rotation refer to the relative ring and the applied load are stationary or loose it can result in housing wear Where
motion between a bearing ring and the load both are rotating at the same speed this cannot be tolerated, either protect the
acting upon it (table 1) Essentially, there are Under these conditions, a bearing ring bearing seat surface or select a bearing
three different conditions: normally does not creep and there is no that accommodates the axial displacement
risk of fretting corrosion or wear In this within itself (cylindrical roller, needle roller
• Rotating loads case, the ring does not need to have an or CARB bearing) These bearings can be
These loads occur where either the bear- interference it mounted with an interference it for both
ing ring or the applied load is stationary rings
while the other rotates A bearing ring • Direction of load indeterminate
mounted with a loose it will creep on its This refers to variable or alternating exter-
seat when subjected to a rotating load, nal loads, sudden load peaks, vibration or
and this can lead to fretting corrosion and unbalanced loads in high-speed applica-
eventually wear To prevent this from hap- tions These give rise to changes in the
pening, an adequate interference it, direction of load, which cannot be accur-
between the ring subjected to rotating ately described Where the direction of
load and its seat, is required For the pur- load is indeterminate and particularly
pose of selecting its, loads that oscillate where heavy loads are involved, there is a
(such as loads acting on connecting rod risk of fretting corrosion or wear You
bearings) are considered to be rotating should use an interference it for both
loads rings The same it as for a rotating load is
normally suitable Where the outer ring

Bearing interfaces Conditions of rotation Schematic illustration Load condition Recommended its Table 1

Operating conditions

B.6 Rotating inner ring Rotating inner ring load Interference it for the inner ring
Stationary outer ring Stationary outer ring load Loose it for the outer ring possible
Constant load direction

Rotating inner ring Stationary inner ring load Loose it for the inner ring possible
Stationary outer ring Rotating outer ring load Interference it for the outer ring
Load rotates with the inner ring

Stationary inner ring Stationary inner ring load Loose it for the inner ring possible
Rotating outer ring Rotating outer ring load Interference it for the outer ring
Constant load direction

Stationary inner ring Rotating inner ring load Interference it for the inner ring
Rotating outer ring Stationary outer ring load Loose it for the outer ring possible
Load rotates with outer ring

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