Specifications
11– 8
11.SELECTION
Type
Linear
movement
Rotary
movement
Vertical
movement
Mechanism Equation
Servo motor
Counter
weight
Servo motor
Servo motor
η
W
Z
1
Z
1
Z
2
F
C
T
LO
F
O
Z
2
W
2
W
1
1/n
Load
Guide
11-6 Load torque equations
TL =
F
2 x 10
3
• π
• η
F • ∆S
2 x 10
3
• π
• η
• =
V
N
.............................................................. (11-15)
F : Force in the axial direction of the machine in linear
motion [N]
F in Equation 11-15 is obtained with Equation 11-16
when the table is moved, for example, as shown in the
left diagram.
F = Fc + µ • (W • g + FO) .................................... (11-16)
Fc : Force applied in the axial direction of the moving
part [N]
FG : Tightening force of the table guide surface [N]
W : Full weight of the moving part [kg]
TL =
1
n
•
1
η
• TLO + TF ................................ (11-17)
TF: Load friction torque converted into equivalent value
on servo motor shaft [N • m]
During rise
TL = TU + TF .................................................... (11-18)
During fall
TL = - TU • η
2
+ TF ........................................... (11-19)
TF: Friction torque of the moving part [N • m]
TU =
(W
1
-
W
2
) • g
2 x 10
3
•
π
• η
(W
1
-
W
2
) • g • ∆S
2 • 10
3
•
π
• η
• =
V
N
..........................................................(11-20)
TF =
µ(W1 + W2)
•
g
• ∆
S
2 x 10
3
•
π
• η
...................... (11-21)
W1 : Weight of load [kg]
W2 : Weight of counterweight [kg]
Typical load torque equations are indicated below:
Load Torque Equations