Gearhead/Linear Head: Utilizing Maximum Instantaneous Torque

The maximum instantaneous torque is the maximum torque value that can be applied to the gearhead output shaft. (Permissible torque is the value of torque that can be applied continuously.)
During acceleration and deceleration operation, a higher torque is applied to the gearhead output shaft as acceleration torque than during constant speed operation due to the effect of inertia.
According to the following equation, the larger the inertia, the larger the acceleration torque, but if the inertia is large, the acceleration torque can be reduced by increasing the acceleration and deceleration time. In addition, when using a stepper motor or servo motor for positioning operation, the positioning time can be made faster by utilizing the maximum instantaneous torque of the gearhead.

$${Ta}\ [\mathrm{N}\cdot\mathrm{m}] = \frac{({J_0} + {J_L})}{9.55} \cdot \frac{N_M}{t_1}$$

As an example of taking advantage of the maximum instantaneous torque, we will compare the positioning time when an inertia body of the same size is driven. Using the ARM66AC-PS50 + ARD-C, the rotation speed - torque characteristics are shown below.

Conditions

①When the maximum instantaneous torque is utilized

②Assuming that the gearhead has only permissible torque

Driving Condition

Safety Factor: 1.5

Load Inertia Diameter: 300 mm (15 mm thick, steel)

Inertia: 942 × 10 ^{- 4} [kg·m²]

Travel Amount: 90 deg.

The graphs of torque pattern comparison and positioning time comparison are also shown below. It can be seen that the positioning time is 0.1 [s] min. faster when the maximum instantaneous torque is utilized.
When the maximum instantaneous torque is utilized as described above, positioning time can be accelerated and productivity can be improved.