SERIES

Appendices
Capacity Selection for Servomotors
3. Motor Speed
• Load shaft speed
• Motor shaft speed Direct coupling gear ratio 1/R = 1/1
Therefore, n M = n L ⋅ R = 3,000 × 1 = 3,000 (min -1 )
4. Load Torque
(9.8 μ m + F ) P
T L
= B (9.8 × 0.2 × 80 + 0) × 0.005
= = 0.139 (Nm)
2πR η
2π×1 × 0.9
5. Load Moment of Inertia
• Linear motion section
2
2
P B 0.005
J L1
= m = 80 × = 0.507 × 10 -4 (kgm 2 )
2πR 2π×1
• Ball screw J B
=
π
4
B
d B
=
π
× 7.87 × 10 3 × 0.8 × (0.016) 4 = 0.405 × 10 -4 (kgm 2 )
32
32
1
2 1
• Coupling Jc = m C d C = × 0.3 × (0.03) 2 = 0.338 × 10 -4 (kgm 2 )
8
8
• Load moment of inertia at motor shaft
J L = J L1 + J B + Jc = 1.25 × 10 -4 (kg•m 2 )
6. Load Moving Power
2πn
P O = M
T L 2π×3,000 × 0.139
= = 43.7 (W)
60
60
7. Load Acceleration Power
ρ
n L = υ L
= 15
= 3,000 (min-1 )
P B
0.005
2
2
2π J
Pa = n L 2π
1.25 × 10
M = × 3,000 × -4
= 123.4 (W)
60 ta 60
0.1
8. Servomotor Provisional Selection
Selection Conditions
• T L ≤ Motor rated torque
(Po + Pa)
•
< Provisionally selected Servomotor rated output < (Po + Pa)
2
• n M ≤ Rated motor speed
• J L ≤ Allowable load moment of inertia
The following Servomotor meets the selection conditions.
• SGM7J-01A Servomotor
Specifications of the Provisionally Selected Servomotor
Item
Value
Rated Output
100 (W)
Rated Motor Speed 3,000 (min -1 )
Rated Torque
0.318 (N•m)
Instantaneous Maximum Torque 1.11 (N•m)
Motor Moment of Inertia 0.0659 × 10 -4 (kg•m 2 )
Allowable Load Moment of Inertia 0.0659 × 10 -4 × 35 = 2.31 × 10 -4 (kg•m 2 )
Encoder Resolution
16,777,216 pulses/rev [24 bits]
Capacity Selection for Servomotors
453