When the pulley rotates, the centrifugal force generated by each part tends to separate these components from the axis of rotation.
If the mass of the pulley is unevenly distributed and the centrifugal force is unbalanced, the pulley will rotate around its center of gravity, generating additional dynamic pressure
Main factors causing unbalance of pulley
The pulley structure is asymmetrical, the internal material of the pulley is uneven, and the pulley manufacturing and installation are not accurate
The harm caused by imbalance
Unbalanced forces can cause vibration, noise, shortened bearing life, and high fatigue stress
Balanced ends and means
The purpose of the balance pulley is to change the mass distribution of the pulley to reduce the unbalanced inertia force or unbalanced moment of inertia generated when it rotates.
The unbalance can be eliminated by configuring the mass balance inertial force, that is, adding or removing part of the mass at a certain position of the pulley, so that the inertial force system generated when the pulley rotates is a balanced force system, and no additional dynamic pressure is generated in the movement.
Unbalanced inertial force or unbalanced moment of inertia cannot be completely eliminated
The residual unbalance of the calibrated and balanced pulley should not exceed the allowable value
Due to the high cost of school balance, the specified residual imbalance only needs to be equal to the preset application allowable value.
Static balance or one-sided balance
Balancing in a plane is called static balance
All pulleys are recommended to adjust static balance
The stock pulleys only need to be statically balanced because they do not know the future use status at the time of manufacturing.
Dynamic balance or double-sided balance
Balancing in two planes is called dynamic balance
It is recommended to adjust the dynamic balance when the pulley thickness is thick and the speed is high