Influence of Speed and Geometry on Guide Friction Contribution in Global Power Loss of a Silent Chain Drive

Abstract

The subject of the paper is the friction between a tooth chain and the guide. An experimental study is developed with the aim of determining how much is the contribution of chain-guide friction on the total friction in a basic tooth chain transmission. The measurements have been made on a chain friction rig, testing a basic silent chain transmission with transmission ratio equal to 1, with a controlled tensioning device. The following parameters can be adjusted and measured: rotational speed at the input shaft, tensioning force in the chain, position of the guide, temperature and pressure of the oil used for lubrication of chain and guide. Friction torque at the input shaft is a sum of friction torques coming from bearings, chain (pin-link, link-sprocket) and guide (guide-chain). It is measured for different rotational speed, tensioning force, temperature of oil, position of the guide (when the guide is present), with and without guide and separate in the bearings. The paper presents the resulted contribution of the guide in the power loss by friction, as percent of the power loss from friction in chain and guide together. Influence of speed, tensioning force and guide posi-tion is presented.