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2018.
Function
The individual components of the Flex Cam system
described above interact as follows:
The Power Cylinder is actuated by the stroke of the
press.
Once the pressure build-up in the Flex Cam
exceeds the preset pressure in the Force Cylinder, the
Force Cylinder extends.
When the Force Cylinder reaches its working
position, the pressure in the system rises to match the
pressure in the Accumulator. The rest of the displaced
volume of oil is then held in the Accumulator (Power
Cylinder overtravels by approx. 3 - 10 mm).
This overtravel is essential since it ensures that a
constant contact pressure is built up during each stroke.
At the same time the pressure on the Power Cylinder
is relieved (return travel of the press), the Force
Cylinder is reset by the nitrogen gas.
subject to alterations
1
P
= 0
Oil
2
P
= P
+ P
Oil
Work
Retract
3
P
= P
Oil
Accum.
4
P
= P
P
Oil
Accum. +
Retract
Flex Cam
Pressure ratios in the system
180
160
140
120
100
80
60
40
20
0
0
7
17
27
37
47
57
2
12
22
32
42
52
Travel [mm]
The above diagram shows the oil pressure build-up
during the work cycle. Before the working motion, the
oil-system is pressureless. When the Power Cylinder is
actuated, the oil pressure rises to the preset gas pres-
sure in the Cam Unit. As the Force Cylinder continues to
travel, the volume of gas is further compressed until the
work operation is executed. At the same time, the back-
pressure in the system rises due to the punching
operation, for example. Once the operation has ended,
the Power Cylinder continues as far as the end position
of the Force Cylinder. This ensures that the excess
volume of oil is fully absorbed by the Accumulator. At
the same time, the oil pressure rises to match the
charging pressure in the Accumulator.
If a malfunction occurs in the tool part during system
travel and blocks the travel of the Cam Unit, all the
displaced oil is held in the Accumulator. The oil pressure
increases until it equals that of the compressed nitro-
gen in the Accumulator.
The system is protected by an integral rupture protec-
tion device in the Accumulator which opens at 517 bar
to vent the nitrogen. The resulting system security
protects the tool from damage by the Flex Cam.
P
Accumulator
P
Work
Normal
working stroke
Blocking
slide
P
Retract
53
43
33
23
13
3
58
48
38
28
18
8
0
+ P
Retract
9
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