Investigation of dry friction properties of graphite and bronze filled PTFE journal bearing

PTFE is widely used as a dry-bearing material since it does not subject to the stick-slip motion along the wide temperature range, and has a low coefficient of friction. In this study, the coefficient of friction between the bearing sleeve made of graphite and bronze filled PTFE compound and the steel journal is determined on a test rig and then its dependence upon the velocity and temperature increase is investigated. As a result of the tests, it was found that the coefficient of friction was almost constant (about 0.19) in the relatively small velocity and pressure area and the temperature increase over the coefficient of friction was more effective than the increase in velocity. It has also been found that the combination of "small velocity + large pressure" up to a certain temperature for a constant pv value provides lower friction coefficients