On the Lubrication of Crosshead-pin Bearing with Eccentric Journal

Abstract

Usually the lubrication of conventional type crosshead-pin bearings in 2-stroke cycle diesel engines is in quite severe condition due to an oscillating movement of the bearings where the load is always in a downward direction, i.e. on the bottom half bearings. This paper refers to an analysis on the lubrication performance of a special type crosshead-pin bearing equipped with eccentric journals which is expected to have the oil-pumping ability. From the analyses of both the journal motion and the oil-film pressure distribution, it is cleared that the oil-feeding action to each sliding surface from a circumferential oil groove is promoted by the alternate unloading of each bearing. The results of the analyses also show that, for the optimum performance without loss of the above effect, the distance between journal centers should be kept at from 0.75 to 1.25 times the radial clearance, and that the width ratio of the main journal to the whole bearing should be kept at from 0.7 to 0.8.