Abstract
The helical cord is a unique machine element with high tensile stiffness and low bending stiffness, and therefore, is used in various types of rubber belts as a tension member. However, the fatigue failure initiation site of the rubber belts is often located inside of the helical cord. Therefore, the strengthening of the helical cord is important to improve the durability of the rubber belt. The purpose of this study is to improve the bending fatigue strength of the helical cords. An estimation method for the optimum twisting combination of the helical cord was proposed basing on the mechanical analysis. Then, the fatigue failure mechanism of the helical cord , was investigated carrying out some experiments and the mechanical analysis. The results showed that the bending fatigue life was strongly affected by the cord twisting combination of the helical cord, and that the analytical results well explained the experimental results. Therefore, the simplified mechanical model proposed in this study is considered to be useful to design the optimum twisting combination of the helical cord.
