Modeling of reaction film failure in gear lubrication

From a survey of the Literature it has been found that the commonly used P- V curve for predicting scuffing of gears can have a characteristic paraboli c shape which has a minimum value at moderate sliding velocities. Previousl y, there has not been a theory which could explain this trend. A combined m odel for reaction film failure is presented in this paper, which accounts f or mechanical wear and chemical decomposition failure mechanisms in terms o f different pitch Line speed in gear lubrication. Quantitative formulae are proposed for both failure mechanisms. This combined model fits well with p ublished experimental results which indicate that the scuffing load varies with gear speed as an approximate second power polynomial function, providi ng an explanation for the high-low-high variation of scuffing load with the speed of gears. (C) 1999 Published by Elsevier Science S.A. All rights res erved.