Harmonic Drive KDU Series, Руководство пользователя

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Inertia moment calculation
A-4
9
8
7
6
5
Apx
3
2
1
A
ppe
ndi
x
App
付
11
10
Object form
Mass, inertia, gravity
center
Object form
Mass, inertia, gravity
center
Rhombus pillar Hexagonal pillar
Isosceles triangle
pillar
Right triangle pillar
Example of specific gravity
The following tables show reference values for specific gravity. Confirm the specific gravities for the
actual materials.
Material Specific
gravity
Material Specific
gravity
Material Specific
gravity
SUS304
7.93
Aluminum
2.70
Epoxy resin
1.90
S45C
7.86
Duralumin
2.80
ABS
1.10
SS400
7.85
Silicon
2.30
Silicon resin
1.80
Cast iron
7.19
Quartz glass
2.20
Polyurethane rubber
1.25
Copper
8.92
Teflon
2.20
Brass
8.50
Fluorocarbon resin
2.20
(2) Both centerlines of rotation and gravity are not the same:
The following formula calculates the moment of inertia when the rotary center is different from the
gravity center.
I
：
Inertia moment when the gravity center axis does not match the rotational axis (kg
･
m
2
)
I
g
：
Inertia moment when the gravity center axis does not match the rotational axis (kg
･
m
2
)
Calculate according to the shape by using formula (1).
m
：
mass (kg)
F
：
Distance between rotary center and gravity center (m)
z
x
y
C
A
B
ρ
ABC
2
1
m
=
( )
2 2
C B m
24
1
Ix
+ =
( )
2 2
2A C m
24
1
Iy
+ =
( )
2 2
2A B m
24
1
Iz + =
z
x
y
B
B
√
3
A
2
B m
12
5
Ix
=






+ =
2 2
B
2
5
A m
12
1
Iy






+ =
2 2
B
2
5
A m
12
1
Iz
ρ AB
2
3 3
2
=
m
ρ
ABC
2
1
m
=








+ =
2
2
C
3
2
2
B
m
12
1
Ix






+ =
2 2
C
3
2
A m
12
1
Iy








+ =
2
B
A m
12
1
Iz
2
2
3
C
G
=
G
z
x
y
B
A
C
G
1
z
x
y
B
A
G
2
C
ABC ρ
2
1
m
=
( )
2 2
C B m
36
1
Ix
+ =






+ =
2 2
C
3
2
A m
12
1
Iy
3
C
G
1
=






+ =
2 2
B
3
2
A m
12
1
Iz
3
B
G
2
=
2
mF Ig I + =
Gravity center
Rotary center
F