Experimental and Analytical Investigation of Tranient Forcesin Roller Chain Devices

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This project investigates the nature of the transient forces in roller chain drives. Chain drive mechanisms have been in use since the 1800's, but despite their age and widespread use, chain drives remain poorly understood. The popularity of the mechanism is expected to increase due to its low cost and simplicity. The auto industry is currently investigating the possibility of using the chain drive as the primary drive mechanism for certain types of future passenger cars. The project comprises an experimental and analytical component. The experimental component has three phases and will investigate the impact force between a roller element on the chain and the sprocket as the roller is seated onto the sprocket, the forces that exist in the chain during all operating conditions, and the forces on the sprocket teeth during operating conditions. Earlier research efforts focused on the construction of the chain drive test machine to be used in the experimental activity. Impact force measurements are obtained by instrumenting a sprocket with strain gauges, obtaining strain gauge measurements for a variety of chain speeds and sprocket sizes and chain tensions, and converting the measurements into force data. These data will be instrumental in determining the effect of impact forces in the galling and pitting of roller elements. The second experimental phase, measurement of the forces in the chain is accomplished by instrumenting the plates of the chain with strain gauges. The force time history information is useful for design purposes. The third experimental phase, measurement of sprocket tooth loads, is accomplished by the use of proximity sensors. All experimental evidence will be used to develop mathematical models to predict the dynamic behavior of chain drives.