Setting Of Rotation Time - SMC Networks C RB 10 Series Operation Manual

4. Setting of Rotation Time

Even if the torque - required by the load in the rotation movement is small, the shaft and/or internal parts
could become damaged depending on the inertia of the load. Therefore, select an appropriate model for
your application by taking the load's moment of inertia, kinetic energy, and rotation time into consideration.
Moment of inertia
(1) Moment of inertia is the tendency of a stationery object to resist rotation, or, conversely, the tendency
of a rotating object to resist stopping.
When the actuator moves an object (load), inertia (kinetic energy) is generated in the object.
The actuator stops at the rotation end, but due to inertia, a large shock (kinetic energy) is applied to the rotary
actuator.
The kinetic energy can be calculated using the formula below.
E = 1/2 x I x ω
(2) There is a threshold of kinetic energy that a rotary actuator allows. Therefore, by finding the moment
of inertia, it is possible to find the threshold value of the rotation time.
The basic formula for finding the moment of inertia is shown below.
Moment of inertia can be found with the basic formula shown below.
I = m x r 2
This represents the moment of inertia for a shaft with mass M, which is located at distance r
from the shaft.
2
E：Kinetic energy
I：Moment of inertia
ω：Angular speed
m:：Weight (kg)
(J)
2
(kg/m )
(rad/s)
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