Dynamic Analysis of a New Type of Passive Balancers for Imbalanced Rotating Shafts

In this paper a new type of passive balancers (PB) introduced rather than common balancers used in the literature by previous scholars. One of the main problems of engineers is to suppress the unwantedvibration amplitudes happen in rotating imbalanced shafts. Many efforts have been done to this end andthe use of automatic dynamic balancers (ADB) is one of the efficient methods when the system is rotating with angular velocities greater than the first natural frequency of the system. Although this approach is an effective way to overcome the undesired vibration behavior nonetheless has some negative points whichlimit the use of it in industrial applications. A properly designed automatic ball balancer can effectively reduce vibrations at steady state. However, it increases vibrations at transient state compared with rotors without an automatic ball balancer. As seen in the paper the proposed PB has a very good ability to modify the transient response of the system remarkably which is extremely very important issue in designing the rotating mechanisms.To evaluate the dynamic response of the proposed PB in comparison with common ADB, amathematical model with a two-ball ADB accompanied with the couple of pendulums is constructed. Equations of motion are derived utilizing Lagrange's equations, and the simulations are presented using Delphi. This paper is suitable to provide useful guidelines for designing a more reliable PB with better dynamic characteristics

Keywords:

ball-balancer , pendulum , vibration , rotating shaft