Audible Noise Produced by the Sporadic Changes of Tensile Forces in a Belt Driven System

The tensile forces of a drive belt have static and dynamic components. Static forces are related to the steady power transmission, whilst the dynamic forces are dependent on the eccentricity of the pulleys, non-uniformity of the belt and pulley surfaces and the dynamic loading. This study describes a successful endeavour to analyze the effects of variation of tensile forces on the noise emission of the drive system. In belt driven systems, the static tensile forces are dependent on initial tensioning, mean value of power transmission and belt speed. Dynamic tensile forces, which cannot be limited by the elastic extension and contraction of the belt relative to rigid pulley surface, are also considered as one of the major causes of noise emission. Results show that the tensile forces can cause parametric excitation of the transverse flexural vibrations that are dominant at twice the fundamental frequency of the belt span. The variations of static tensile forces and sporadic changes, whose fluctuations cause side peaks of the fundamental frequencies, can be considered in an analytical model by neglecting the inertia of the pulley and bending stiffness of the belt. Tensile forces can lead to further vibration and noise problems in belt driven systems by causing increase of torsional and rectilinear vibrations and amplification of noise emissions.