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Festo 7EGC_TB_KFb_en
4.1.2
Checking and setting the toothed belt pretension
The toothed belt pretension is determined by measuring the basic oscillation
(natural frequency) of the toothed belt with a fixed and freely oscillating strand
length (L). Since the freely oscillating strand length (L) cannot be measured
directly, the distance from the clamping body to one of the drive covers (L1) is
set by moving the slide. The oscillation measurement is then carried out at this
point.
Warning
The toothed belt pretension has a direct influence on the service life of the
toothed belt and the performance of the toothed belt axis. Extreme care
must therefore be exercised when checking it.
Overstretching the toothed belt shortens its service life. Slowly increase the
toothed belt pretension to the correct value.
Before the toothed belt pretension can be measured, the slide must be
moved back and forth a number of times so that the toothed belt can fully
settle and differences in tension can be equalised.
Documents
The easiest way to check the toothed belt pretension is using the toothed
belt pretension test equipment (see section
6.3 “Devices and meters”
). The
work instructions required for this as well as the setting values can be found
in the associated operating instructions in the appendix to this document.
L
L1
Checking the toothed belt pretension
•
Place the toothed belt axis on the work surface as shown with the slide facing
upwards.
•
Lever off the cover cap from the drive cover.
•
Set the distance between the drive cover and clamping body (L1) (see table).
Type
Distance L1
EGC-50
222 mm/50 mm
1)
EGC-70
222 mm/50 mm
1)
EGC-80
222 mm/50 mm
1)
EGC-120
222 mm/50 mm
1)
EGC-185
222 mm/50 mm
1)
1)
Alternatives for toothed belt axes with very short stroke.
Note
The longer strand length should preferably be set if possible. A longer freely
oscillating strand length reduces the variation of the measurement results.
L1
