Fatigue Life
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Fatigue life, L10 [rev, hrs], is a statistical measure of the life which 90% of a large
group apparently identical rolleing element bearings will complete or
exceed. For a single bearing, L10 also refers to the life
associated with 90% reliability.
The relationship
between fatigue or rating life, capacity and load is:
|
(6) |
where |
L10 rev = Rating Life [106 rev]
C = Dynamic capacity [lbf]
Pe = Equivalent radial load |
|
To obtain the rating
life in [hours], use
|
(7) |
where |
L10 hrs = Rating Life [hours]
ne = Equivalent radial load |
|
In case of constant
speed, the equivalent speed equals the constant bearing speed. In all
other cases the quivalent speed is the weighted average of all individual
speed components.
|
(8) |
where |
ni = individual speed component [rpm]
ti = time interval in [percent] of total time |
|
In cases of constant
load, the equivalent radial load equals the constant load. To compute
the equivalent load for all other cases, use:
|
(9) |
where |
q = 10/3 for
roller bearings
Ft = individual radial load [lbf] |
|
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