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Rexroth IndraDyn A
9.16 Grease Service Life
Reduction factors
Description
Description Influence
Influence of dust and
moisture at the
function surfaces of
the bearing
Influence of impact
load, vibrations and
oscillations
Influence of higher
bearing temperatures
Influence of high load
Influence of air flows
through the bearing
With centrifugal effect
or vertical shaft
depending on sealing
Calculation
DOK-MOTOR*-MAD/MAF****-PR03-EN-P
Grease service life (t
of a bearing as a consequence of lubrication failure.
Note that unfavorable operating and ambient conditions reduce the
grease service life. When calculating the grease service life to be
expected (T
), consider certain reduction factors for unfavorable
fq
operating and ambient conditions for each individual application. The
following table indicates the reduction factors in accordance with the
publication no. WL 81 115/4 DA by FAG Kugelfischer AG.
moderate
f
strong
1
very strong
moderate
f
2
strong
very strong
moderate (up to 75°C)
f
strong (75...85°C)
3
strong (85..120°C)
P/C=0.1...0.15
P/C=0.15...0.25
f
4
P/C=0.25...0.35
insignificant flows
f
5
significant flows
f
vertical
6
Fig. 9-42:
Reduction factors for grease service life
Fig. 9-43:
Calculation of the expected grease service life
Note:
Ensure that the permitted loads from chapter 9.13 "Shaft
Loads" are not exceeded.
If the deployment duration of the motor is limited by the expected grease
service life, the deployment duration of the motor can be increased in
marginal cases by using the standard bearing in place of the reinforced
) is defined as the time from start-up until breakdown
f
Factor
Comment
0,9....0,7
For this environment, Rexroth offers the
option "radial shaft sealing ring".
0,7....0,4
When this option is used,
f
= 1
0,4....0,1
1
e.g. for machine tools and printing
0,9....0,7
presses
e.g. for materials-handling technology
0,7....0,4
(portals)
0,4....0,1
e.g. for punches, presses
The bearing temperature depends on the
0,9....0,6
motor load.
Use of a special high-temperature grease
0,6....0,3
results in
- load 0...70%
0,3....0,1
- load 71...100%
With corresponding load of the
1,0....0,7
shaft/bearing according to the respective
shaft load diagram, the following applies
0,7....0,4
to IndraDyn A motors
- load 0...70%
0,4....0,1
- load 71...100%
With correct operation, there is no
0,7....0,5
influencing air flow in the motor
f
= 1
5
0,5....0,1
With horizontal motor installation
0,7....0,5
f
= 1
6
=
×
×
×
×
t
t
f
f
f
f
fq
f
1
2
3
4
9-33
Application Notes
f
= 1
3
f
= 0.99...0.7
3
f
= 1
4
f
= 0.99...0.7
4
×
×
f
f
5
6
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