Mitsubishi Electric MELDAS MDS-B-SVJ2 Series Specifications And Instruction Manual page 276

• Load inertia: J
L
This is the sum of the total rotation load inertia and the linear movement inertia.
J = 13.9 + 4.6 = 18.5 (kg·cm
L
When looking at the load inertia components, the linear movement weight tends to increase.
However, the rotation load generally accounts for most of the inertia. The load inertia does not
change much even if the workpiece weight changes greatly in the table axis.
(2) Obtaining unbalance torque
The unbalance torque is obtained from the moving object weight. Here, the drive system
efficiency is calculated as 1.
Refer to section "11-6 Motor shaft conversion load torque".
− W ) · g · ΔS
(W
1 2
T =
U
3
2 × 10
(3) Obtaining friction torque
The friction torque is obtained from the moving object weight and friction coefficient. Here, the
drive system efficiency is calculated as 1. Refer to section "11-6 Motor shaft conversion load
torque".
F · ΔS
T =
F
3
2 × 10 π · η
(4) Selecting the appropriate motor from the load inertia ratio
Because it is a machine tool, the HC
maximum speed of 3000r/min. or more is required because of the rapid traverse speed and gear
ratio. Furthermore, the motor to be selected is limited to the HC 3B Series because a motor with
brakes is required. The load inertia for all the HC53B to HC153B motors in the table below is
judged to be appropriate if the load inertia is within 5-fold of the recommended load inertia ratio.
Motor type
HC53B
HC103B
HC153B
(5) Selecting the appropriate motor from the short time characteristics
(acceleration/deceleration time constant)
The acceleration/deceleration time constant is calculated using expression (11-2), and it is judged
whether it satisfies the target acceleration/deceleration time constant of 120msec.
HC53B : ta =
95.5 × (0.8 × T
(msec)
HC103B : ta =
95.5 × (0.8 × T
(msec)
HC153B : ta =
95.5 × (0.8 × T
The motors that satisfy the conditions from the calculation results above are the HC103B and
HC153B.
Motor type
HC53B
HC103B
HC153B
Chapter 11 Selection
2
)
(410 − 0) × 9.8 × 10 × 2
=
π · η 2 × 10
μ · W · g · ΔS
=
3
2 × 10 π · η
Motor Series is required for precise control, and a motor
Motor inertia Load inertia
2
(kg·cm ) (kg·cm
8.6 18.5
15.7 18.5
22.0 18.5
) × N
(J + J
L M
− T − T
MAX U
) × N
(J + J
L M
− T − T
MAX U
) × N
(J + J
L M
− T − T
MAX U
Maximum torque Total inertia
(N·m) (kg·cm
8.82 27.1
16.7 34.2
28.4 40.5
11-16
= 4.3 (N·m)
3
π × 1 × 3
0.02 × 410 × 9.8 × 10 × 2
=
3
2 × 10 π × 1 × 3
Load inertia
2
) magnification
2.15
1.18
0.84
(18.5 + 8.6) × 3000
=
95.5 × (0.8 × 8.82 − 4.3 − 0.09)
)
F
(18.5 + 15.7) × 3000
=
95.5 × (0.8 × 16.7 − 4.3 − 0.09)
)
F
(18.5 + 22.0) × 3000
=
95.5 × (0.8 × 28.4 − 4.3 − 0.09)
)
F
Acceleration/
deceleration time
2
) constant
(msec)
320.5
119.9
69.4
= 0.09 (N·m)
Judgment
○
○
○
= 320.5
= 119.9
= 69.4 (msec)
Judgment
×
○
○