Desoutter CVIR II, Руководство оператора, Страница: 57 / 72

02/2014 57 / 72
6159933910
Issue no: 04
CVIR II
9 - tIghteNINg stRAtegy guIDe
9.1 - torque control
Torque control strategy is the most common use.
It offers the insurance that the torque has really been
applied to the assembly but doesn’t give the complete
insurance that the assembly is correctly done.
For example the parts could be not tighten enough or
not tighten at all when there is joint issues, i.e. "cross
threads", missing washer, broken bolt, larger size of bolt;
low quality bolt (even if the torque has been applied by
the tool).
This strategy is selected when there is a wide angle
dispersion and consequently it is not possible to detect
the joint issues.
Some examples of joints:
● Drum washing machine
● Seat mechanism
● Outside rear mirrors
● Cooling/heating components
Torque
Time
Target
Target torque
Search
sequence
Run down
speed
Final
speed
Run down torque
Max
Min
The recorded value is:
Peak torque
spindle stop
● IF torque ≥ target torque
Accept report
● IF min. torque ≤ peak torque ≤ max. torque
Accept report with current monitoring (optional)
● IF min. torque ≤ peak torque ≤ max. torque
● AND min. current ≤ final current ≤ max. current
9.2 - torque control and angle monitoring
Torque control strategy coupled with a torque and angle
monitoring is adapted for most assemblies.
It offers:
● The insurance that the tightening operation is
correctly done,
● A regular joint quality.
To reach this performance, we monitor the angle to
detect joint issues, i.e. "cross threads", missing washer,
broken bolt, larger size of bolt; low quality bolt.
In case of batch count, this strategy will detect any
re-tightening of the bolt.
Torque Angle
Time
Target
Peak torque
Final angle
Angle
threshold
Max
Min
Max
Min
The start of the angle threshold counting should be
within the linear area of the torque increase.
The angle measurement takes into account the torsion
/ back torsion of the spindle by measuring the angle
during the torque drop phase, until the threshold value of
the angle counting start is overstepped.
The recorded values are the following: peak torque and
final angle.
spindle stop
● IF torque ≥ target torque
● OR angle > safety angle
Accept report
● IF min. torque ≤ peak torque ≤ max. torque
● AND min. angle ≤ final angle ≤ max. angle.