Change of Relative Local Velocity in Pulley Groove at Sliding between Belt and Pulleys for Metal Pushing V-Belt Type CVT

The objective of this study was to investigate the change of relative local velocity in each pulley groove at sliding between the belt and pulleys for a metal-pushing V-belt type CVT where micro elastic slips were inevitably accompanied to transmit power, while the transmissions were widely adopted to provide comfortable driving by continuously automatically adjusting the speed ratio. Local changes of wrapping radial position and velocity of the belt in each pulley groove of the CVT were simultaneously measured by a potentiometer with a spinning roller in the experiments. The mechanical power generated by the AC motor was transmitted through the CVT unit from the driving axis to the driven axis as usual under practical conditions while the speed ratio was set to 1.0. Pulley clamping force was applied by oil pressure. Test results showed that the wrapping radial position of the belt was slightly decreased at the location from the entrance to the exit in the driving pulley groove and significantly decreased in that of the driven pulley. The relative local velocity decreased significantly near the entrance and then increased near the exit of both of the driving and driven pulley grooves. The change of relative local velocity was almost in agreement with that of the wrapping radial position of the belt in the entrance of driving and the exit of driven pulley groove of the CVT. This study found that the change of relative local slip in each pulley groove was induced by the local changes of the wrapping radial position and velocity of the belt in each pulley groove of the CVT.