Technical Materials
Selection Method
●
Calculating the moment of inertia
Confirm whether or not the calculated moment of inertia satisfies the requirements for the permissible moment of inertia
for the model.
If the calculated moment of inertia is less than the permissible moment of inertia, the product may be used.
If the calculated moment of inertia is greater than or equal to the permissible moment of inertia, the product may not be used.
Please select a different model or reduce the mass or rotational radius.
For the permissible moment of inertia for each model, please consult the "Angular Velocity versus Permissible Moment of
Inertia" graph.
Confirm whether or not the calculated torque satisfies the requirements for the maximum output torque for the model.
If the calculated torque is less than the maximum output torque, the product can be used.
If the calculated torque is greater than or equal to the maximum output torque, the product cannot be used.
Please select a different model or reduce the mass or rotational radius.
For the maximum output torque for each model, please consult the "Angular Velocity versus Output Torque" graph.
When selecting a rotary shaft, calculate the moment of inertia and load torque for the usage conditions and make a selection
where the permissible moment of inertia and maximum output torque will not be exceeded.
Refer to the formula below as a representative example and calculate the moment of inertia for the workpiece and mounting
jigs you will be using.
Table
Diameter:
D
(m) Height:
L
(m)
Mass:
m
(k
g
)
Workpiece
Diameter:
D
1
(m) Height:
L
1
(m)
Mass:
m
1
(k
g
)
Quantity:
n
(pieces)
Density:
ρ
(k
g
/m
3
)
(Notes)
・
All workpieces are considered to be of the same shape and mass.
・
All workpieces are considered to be at the same distance from the
center point.
(Reference) Moment of Inertia for Multiple Rectangular Solids Combined
Rectangular solid:
Depth
A
(m), height
B
(m), width
C
(m), mass
m
1
(k
g
)
Cube:
Depth
A
(m), height
A
(m), width
A
(m), mass
m
2
(k
g
)
Density:
ρ
(k
g
/m
3
)
(Reference) Moment of Inertia for Multiple Cylindrical Columns Combined
Ix
1
–
8
m
·
D
2
1
–
8
n
·
m
·(
D
1
2
+8
l
2
)
=
m
m
1
π
–
4
ρ
·
L
·
D
2
:
π
–
4
ρ
·
L
1
·
D
1
2
:
+
[k
g
·m
2
]
m
2
(2·
A
2
+ 12·
l
2
2
)
Ix
1
–
12
m
1
(
A
2
+
B
2
+ 12·
l
1
2
)
1
–
12
+
=
:
:
:
:
ρ
·
A
·
B
·
C
ρ
·
A
3
Distance between X
0
and X
1
(center of rotation X
0
)
(m)
m
1
m
2
l
1
l
2
Distance between X
0
and X
2
(center of rotation X
0
)
(m)
[k
g
·m
2
]
Selection Procedure
17
Summary of Contents for ET20 Series
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