
4. SELECTING A MOTOR
B–65142E/04
DESCRIPTIONS FOR THE α series
46
Enter values to two digits past the decimal point. (e.g. 0.2865 ³ 0.29)
Enter load inertia applied on transfer mechanisms other than couplings,
moving objects and ball screw.
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.
Enter the maximum value of the force applied during cutting by the force
in the feed axis direction.
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.
D Inertia of coupling,
reduction gear and
pulley
D Steady–state load torque
D Cutting thrust
D Maximum cutting torque