Motor Shaft Conversion Load Torque - Mitsubishi Electric MDS-D-SPJ3 Specification Manual

7-1-3 Motor shaft conversion load torque

The calculation method for a representative load torque is shown.
Type
Linear
movement
Servo-
motor
Rotary
movement
Z
Servomotor
1/n
Vertical
movement
Mechanism
Z F
1
c
F
0
Z
2
W
T
L0
Z
1 2
Servomotor
Counter-
weight
Load
W
2
W
1
MDS-D-SVJ3/SPJ3 Series Specifications Manual
Calculation expression
V
F F
. (
) =
T =
L
3
πη
N
10
10
T :Load torque(N•m)
L
F:Force in axial direction of the machine that moves linearly(N)
η: Drive system efficiency
V:Speed of object that moves linearly(mm/min)
N:Motor speed(r/min)
ΔS:Object movement amount per motor rotation(mm)
Z ,Z :Deceleration ratio
1 2
F in the above expression is obtained from the expression below when
the table is moved as shown on the left.
F=Fc+μ(W•g+F )
0
F :Force applied on axial direction of moving section (N)
c
F :Tightening force on inner surface of table guide (N)
0
W:Total mass of moving section (kg)
g:Gravitational acceleration = 9.8 (m/s
μ:Friction coefficient
1
Z 1 1
1
. . T .
T = +T =
L η L0 F
η
n
Z
2
T :Load torque(N•m)
L
T :Load torque on load shaft(N•m)
L0
T :Motor shaft conversion load friction torque(N•m)
F
η:Drive system efficiency
Z ,Z :Deceleration ratio
1 2
n:Deceleration ratio
When rising T =T +T When lowering
L U F
T :Load torque(N•m)
L
T :Unbalanced torque(N•m)
U
T :Friction torque on moving section(N•m)
F
. g
(W -W ) (W
V
1 2
1
. (
) =
T =
U
3
πη
N
10
μ . . g . ΔS
(W +W )
1 2
T =
F
3
πη
10
W :Load mass(kg)
1
W :Counterweight mass(kg)
2
η: Drive system efficiency
g:Gravitational acceleration = 9.8(m/s
V:Speed of object that moves linearly(mm/min)
N:Motor speed(r/min)
ΔS:Object movement amount per motor rotation(mm)
μ:Friction coefficient
7-1 Selection of the servomotor
. ΔS
3
πη
2
)
. T
+T
L0 F
2
T = -T •η +T
L U F
. g . ΔS
-W )
2
3
πη
10
2
)
7 - 11