Impact dynamics of axially moving chains with tensioners

Chain drives have been widely used since they are one of the most efficient power transmission mechanisms. However, the noise and the vibration created by the chain drives has always been a problem, especially in today's high speed, light weight and high quality products. The impact in the chain/sprocket meshing process has been identified as a major noise source. In many chain drive systems, a tensioner is used to improve performance by eliminating flop and sway on the slack side and reducing noise and vibration on the tight side. In spite of the production use of tensioners, the effects of tensioners on the chain/sprocket impact dynamics has not been researched.; A comprehensive dynamic model of chain drives with tensioners has been derived. Based on the model, the tensioner effects on the impact dynamics is investigated. It is found that the impact dynamics can be significantly affected by the tensioner mass, stiffness and location along the chain span. The amplitude fluctuation related to meshing impact with respect to sprocket speed can be reduced by tuning the tensioner parameters. A design optimization strategy to reduce the fluctuation with respect to sprocket speeds is developed and proposed.; Experimental investigations have been performed to investigate the dynamic characteristics of the chain drive system under the effects of tensioners. The first natural frequency of the chain drive is measured with different chain tensions and different tensioner parameters. The results from the tests show that the fundamental behavior of the analytical model is valid. Furthermore, experimental investigation of a chain drive system with a tensioner correlates with trends predicted in the analytical model.