7.1 Case: Horizontal axis of packaging machine
Requirements: Output speed of 200rpm, load torque of 80Nm, occasional peak torque of 150Nm, radial force of 500N, ambient temperature of 40 ° C, and 200 start stop cycles per hour.
Motor speed 3000rpm → Speed ratio i=3000/200=15
Equivalent torque of 80Nm, peak value of 150Nm < Ma2 (usually ≥ 2 times rated), temperature coefficient fT=0.9, speed coefficient fn=1, cycle coefficient fz ≈ 1.2
The required Mn2 is ≥ 80 × 0.9 × 1.2 ≈ 86Nm → TQ 090 2/15 (Mn2=155Nm) is selected to meet the requirement.
7.2 Misconceptions Reminder
Neglecting radial/axial force verification resulted in premature bearing damage.
Failure to consider the cyclic frequency coefficient in frequent forward and reverse rotation results in premature fatigue of the gear.
The ambient temperature is above 40 ° C without derating, resulting in insufficient thermal power.
Choosing too low a backlash may increase costs, and it should be reasonably selected based on actual positioning accuracy requirements (such as robots requiring ≤ 3arcmin, conveyor belts can be relaxed to 10arcmin).
