Miller SRL2-M Series
Rodless Cylinders
27
Inertia Moment Consideration
When the weight is stopped at the end of the stroke by the cylinder
cushion, inertial force is created. This inertial force (Fi) can be
determined by using the formula:
Fi = WG
W = Weight attached to the piston table (lbs.)
G = Inertia factor (Figure 16)
Example:
A speed of 40 in./sec. corresponds to an inertia factor G of 13.
The inertial force calculated would then be multiplied by the
distance from the center of gravity of the load to the centerline of
the cylinder, and added to the previously calculated M1 and M3
moments. This will give an M1 Total and M3 Total. Ensure that the
M1 Total and the M3 Total do not exceed the [M1] and [M3] values
shown in Figure 9. If they exceed these values, an external shock
absorber must be used.
See pages 16-19 for additional information on shock absorbers.
External Stops
When a cylinder piston is stopped externally, it creates an
additional moment equal to the cylinder actual force (Fa) times the
distance (S). This additional moment, plus the previously calculated
Weight-Moment factor, should not exceed the allowable values.
See page 23.
When reducing the stroke with external stops, remember that the
cushion length and the energy absorption capacity are not directly
proportional. Reducing the cushioning distance by 50%
corresponds to a 30 to 40% cushion effectiveness.
40
40
60
80
35
30
25
20
20
15
10
5
SPEED (IN PER SEC) (V)
INERTIA FACTOR (G)
F
F
M
S
x
=
a
a
S
The following pages show the data that is required in order to size a rodless
cylinder. They are typical load-mounting diagrams reflecting the three types
of mounting conditions with either a resistive force or weight transfer
application.
Condition 1: Cylinder mounted horizontal, table mounted horizontal
Condition 2: Cylinder mounted horizontal, table mounted vertical
Condition 3: Cylinder mounted vertical, table mounted vertical
The last page shows a cylinder mounted as in Condition 1, with the load
guided and using a floating joint on the table.
If you wish Miller Fluid Power to size the rodless cylinder for you, please
photocopy the form that fits your application, fill in the necessary data with
any other information available about the application and FAX the data to
Miller at Bensenville, Illinois using the FAX number shown on the back of
the catalog.
Figure 16
Figure 17
SRL2-M Rodless Cylinder Sizing Forms
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