Analysis of Self-induced Vibrations in a Pushing V-belt CVT

The paper will focus on investigations which were made during a cooperation project with an important supplier of gears. In some working points of a pushing V-belt CVT an unexplainable noise occurs. To find out the reason of this phenomena a simulation model is built up which contains an elastic model of the pulley sheaves as well as a detailed description of the belt. With this model investigations are made but the results do not include the expected vibration so far. An analytical approach is used the calculate possible eigenfrequencies of the belt. Together with the belt forces from the simulation model it is shown that the eigenfrequencies of the belt are in the same range as the measured frequencies of the noise. In the next step the simulation model is extended by a non-constant friction law. Investigations show that if the friction coefficient in the contact between pulley and elements decreases with the relative velocity, the belt could be excited by the friction-contact.