Datasheet

86
17
Load Carrying Capacity and Service Life
17.2 Calculation of Service Life L in Accordance with the DIN ISO Standard
17.2.1 The Formula for Calculating the Nominal Service Life for Ball
Guideways in Meters is as follows:
L = a
∙
󰇧
Ceff
󰇨
3
∙
10
5
m
P
a
C
eff
P
L
= Event probability factor
= Effective load carrying capacity N
= Dynamic, equivalent load in N
= Nominal service life in m
Event probability factor a
The load carrying capacities for roller-contact bearings correspond to the DIN ISO
standard. This represents a value from the service life calculation, which has a 90%
chance of being exceeded during operational use of the guideway.
If the previously mentioned theoretical service life probability factor of 90% is not
sufficient, the service life values will need to be adjusted by a factor a.
Event probability in %
90 95 96 97 98 99
Factor a 1 0.62 0.53 0.44 0.33 0.21
17.2.2 The Formula for Calculating Nominal Service Life in Hours is as
follows:
Lh =
L
=
L
2
∙ s ∙ n ∙ 60 60 ∙ vm
L
L
h
s
n
v
m
= Nominal service life in m
= Nominal service life in h
= Stroke length in m
= Stroke frequency in min
-1
= Medium travelling speed in m/min
17.2.3 Effective Load Carrying Capacity C
eff
Constructive and external influences can reduce the dynamic load capacity C of
MINI-X products in such a way that C
eff must be calculated.
Ceff = fK · C
Ceff
fK
C
= Effective load carrying capacity N
= Contact factor
= Maximum permissible dynamic load carrying capacity in N