Power Loss and Optimum Tensioning of V-Belt Drives

Abstract

In a previous report [2] the author presents a new theory for V-belt drives. In that work special attention is directed to the motion of the belt. Stress variation in the cord of the belt is treated in another report (3). In the present report the earlier theory is extended and the main interest here is how the power loss is influenced by different belt and drive properties. The contribution to the power loss can be divided into two main parts viz: losses due to external friction (sliding between belt and pulley) and internal friction (sliding between molecules-hysteresis). The former losses are treated theoretically and the latter experimentally. A further separation is also made and power losses due to external friction arising when the belt enters and leaves the pulley are specially treated. Different types of contribution to the power loss are calculated by Gervas and Pronin (4) and in another paper (5) Gervas measures the internal friction losses caused by the bending (flexure) of the belt. However, the experimental method used didn’t separate the losses due to external and internal friction. In a chapter on optimum tensioning of a belt drive, different types of losses are combined and the efficiency reaches a maximum for a certain combination of transmitted power and pretension.