Mechanical vibrations and dynamics
Vibrations in belt-pulley transmission systems
Transmission belts often presents vibrations and stick-slip phenomena. Such issues are usually related to misalignments between pulleys and out of tolerance pulleys.
A transverse belt vibration has been identified in a rotating machine presenting a target speed delay.
The figure shows the speed delay measure: zero means no difference between real and target speed of the driven pulley.
The negative peaks in the speed delay plot appear at precise frequencies. Such frequencies corresponds to sub-harmonics of the natural frequencies of the translating belt. Furthermore, the natural frequencies of the belt depends on its translating velocity and therefore on the rotating speed of the pulley.
In our system, vibrations was produced by an out of circularity of the driven pulley. The vibrations of the system have been kept under control by simply improving the molding process of the driven pulley. By reducing the vibrations, the speed delay has been strongly reduced.
Natural frequencies of the belt.
Campbell diagram of a translating belt showing the natural frequencies of three modes and the harmonics of the rotation speed.
Mechanical vibrations and dynamics: