Specifications
11– 9
11
11.SELECTION
Type
Cylinder
Square
block
Object which
moves linearly
Object that is
hung with
pulley
Converted
load
Mechanism
Axis of rotation is on the cylinder
center
Axis of rotation is off the cylinder
center
Equation
Servo motor
Servo motor
Axis of rotation
Axis of rotation
L
øD
1
øD
2
R
Axis of rotation
D
R
V
W
W
D
N
a
a
b
b
Load A
J
A
J
31
J
B
N
3
J
21
J
11
J
22
N
2
N
1
JLO =
π • ρ • L
32
W
8
• (D - D )
4
1
4
2
• (D + D )
2
1
2
2
=
...... (11-22)
ρ : Cylinder material density [kg/cm
3
]
L : Cylinder length [cm]
D1 : Cylinder outside diameter [cm]
D2 : Cylinder inside diameter [cm]
W : Cylinder weight [kg]
Reference data: material density
Iron : 7.8 x 10
-3
[kg/cm
3
]
Aluminum : 2.7 x 10
-3
[kg/cm
3
]
Copper : 8.96 x 10
-3
[kg/cm
3
]
JLO =
W
8
• (D + 8R )
22
............................................(11-23)
JLO = .........................................(11-24)
W : Square block weight [kg]
a, b, R : Left diagram [cm]
JL =
V
600 • ω
W • ==
∆S
20 • π
W •
1
2 • π • N
V
10
W • •
22
........................(11-25)
V : Speed of object moving linearly [mm/min]
∆S : Moving distance of object moving linearly per servo
motor revolution [mm/rev]
W : Object weight [kg]
JL =
D
2
W •
2
+ JP ...................................................(11-26)
JP : Pulley inertia moment [kg • cm2]
D : Pulley diameter [cm]
W : Object weight [kg]
JL = J11 = (J21 + J22 + JA) •
N2
N1
2
+ (J31 + JB) •
N
3
N
1
2
.................
(11-27)
JA, JB : Inertia moments of loads A, B [kg • cm
2
]
J11 to J31 : Inertia moments [kg • cm
2
]
N1 to N3 : Speed of each shaft [r/min]
11-7 Load inertia moment equations
Typical load inertia moment equations are indicated below:
Load Inertia Moment Equations
a
2
+
b
2
3
W • + R
2