Lenze DSD - Manual (Page 163)

Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
163
7 Applications
7.15 Synchronous drive of squeegees
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7.15.1 Calculations
For a synchronous drive with squeegees according to the drawing, the following applies:
Conditions
The differential force always has to be smaller than the static friction to prevent slippage. The
coefficient S provides for a safety reserve that can be individually adapted to the application.
For a reliable power transmission from the drive roll to the material the following condition has to
be met. Otherwise a warning appears.
[7-153] Equation 1: Differential force
Contact pressure
The lower roll W
1
ist mounted rigidly. The upper roll W
2
is pressed against roll W
1
with the contact
pressing force F. The contact pressing force F consists of the force due to weight F
W2
and an addi-
tionally acting force F
add
(e.g. by a pneumatic cylinder).
The proportion of the force due to weight F
W2
depends on the mounting position (angle of tilt β) of
the roll pair W
1
, W
2
, with regard to the vertical.
[7-154] Equation 2: Contact pressing force
Stationary torque
The stationary torque for the lower roll W
1
(drive roll) is calculated as follows:
[7-155] Equation 3: Stationary torque
Friction torque
The friction of the roll bearings is usually specified by the efficiency η
Brg
. Since the friction torque is
a constant torque, a friction torque M
μ
is calculated by means of the efficiency and the maximum
stationary torque, which is considered as a constant torque.
• The direction of the friction torque is always opposed to the direction of movement and is math-
ematically expressed by the fraction v/|v|.
[7-156] Equation 4: Friction torque
F
in
F
out
– F μ
0
1
S
100
--------- –
 
 
⋅ ⋅ <
F F
W2
F
add
+ =
F m
W2
g cosβ ⋅ ⋅ F
add
+ =
M
sds
f
1
f
2
+ ( )
F
1000
------------- v
v
----- F
in
F
out
– ( ) +
d
1000 2 ⋅
--------------------- ⋅ ⋅ ⋅ =
M
μ
1
η
Brg
---------- 1 –
 
  max M
sds
( ) vv----- ⋅ ⋅ =