Local change of PV value on end faces of rocker pins of chain type CVT (Continuously Variable Transmission) under transmitting condition

The objective of this study was to investigate the local change of PV value on the end faces of rocker pins driven by a high-performance chain under transmitting torque conditions. A test bench system was prepared to evaluate the behavior of the chain belt under driven state. Local contact force of the pin was measured by strain gauges attached to a specific modified pin for which the thickness was partly reduced by machine work. Change of PV value on the end face of the pin was also calculated by considering the change of pressure generated by contact force and sliding velocity of rocker pin. Autorotation angles of the rocker pins in the groove of driving and driven sheaves were investigated by replacing the normal pulleys with visibly transparent sheaves made with acrylic resin. The representative loading points were also calculated assuming that the pin was regarded as a simple beam where an eccentric compressive load was applied. Test results showed that slight bending deformations of the pins were observed when severe contact force was applied between pin and sheave. The observations also revealed that the angles of following pins of the chain belts rapidly changed at entrance and exit of the groove of driving pulley when the wrapping radius of the chain belts was relatively small. This study found that local change of PV value was increased by off-setting of the representative loading position where contact force between pin and sheave was regarded to be applied at the point during autorotation of the pin.