Experimental investigation of chain link forces in continuously variable transmissions

This paper deals with the experimental analysis of link tension distribution in a chain type continuously variable transmission. We have developed an ad hoc measuring device constituted by a data-logger that is fixed at the chain and moves with it. The data-logger records the strain data from a strain gauge and stores them in a flash memory card. We have been able to measure the tensile force acting on a single chain link in a wide range of working conditions. Our measurements have shown that an almost perfect linearity (which has a clear theoretical explanation) exists between the clamping force and the link tension distribution. We have also found that the link tension distribution is less sensitive to the torque load, which mainly influences the local slip between the chain and the pulley and hence the time required by the link to cover the entire contact arc. We have also carried out a comparison between theoretical predictions and experimental data. We have found a relatively good agreement that confirms the validity of the theoretical approach