
B-65262EN/03 SPECIFICATIONS FOR THE αiS/αi SERIES 3.SELECTING A MOTOR
- 73 -
- Steady-state load torque
Enter the torque obtained by calculating the force applied for moving
the machine tool and state-state components such as friction
(including holding torque in the case of a gravity shaft) reflected on
the motor shaft when it is rotating at a fixed speed. (Do not include
any torque required for acceleration/deceleration in this item.) If
details are unknown, use a value calculated logically from the weight
and friction coefficient. Enter the steady-state load torque of the
rotary axis in the same way as for load inertia as it cannot be
calculated logically.
If the load torque values differ during lifting and lowering in the
vertical axis, enter both values. Also, if the load torque values differ
during rapid traverse and cutting feed, enter a notice to that effect.
Since torque produced in low speed without cutting may be applied
even when the motor has stopped, a sufficient allowance is necessary
as compared with the continued rated torque of the motor. Suppress
this load torque so that it is lower than 70% of the rated torque.
- Cutting thrust
Enter the maximum value of the force applied during cutting by the
force in the feed axis direction.
- Maximum cutting torque
Enter the torque value on the motor shaft corresponding to the
maximum value of the above cutting thrust. When you enter this value,
add the steady-state load to the motor shaft converted value for the
cutting thrust.
Since the torque transfer efficiency may substantially deteriorate to a
large extent due to the reaction from the slideway, etc. produced by
the cutting thrust, obtain an accurate value by taking measured values
in similar machine tools and other data into account.
- Maximum cutting duty / ON time
Enter the duty time and ON time with the maximum cutting torque in
the above item applied.
Maximum
cutting torque
Torque
Time
T
t
ON
OFF
ON : Time that the maximum cutting torque is applied
OFF : Time when cutting torque is not applied
Duty : (t/T)
×
100 [%]
ON time = t [min]