On the Load Carrying Capacity of Crosshead-pin Bearing with Eccentric Journal

This paper refers to a new investigation to improve the load carrying capacity of the crossheadpin bearing in a 2-stroke cycle diesel engine. By using a specially equipped journal with a pair of eccentric sections the oscillating bearing can be forced to move up and down just like a piston-pin bearing in a 4-stroke cycle engine. Such a squeeze motion of the oil-film between a journal and a bearing has an ability to increase the oil-film thickness. Then, from the theoretical analyses on effects of various bearing shapes the following features and optimums for design became evident.(1) According to the change of an oscillating direction each sliding face is alternatively unloaded and the oil-pumping ability is generated.(2) In order to keep the oil-film pressure lower than the elastic flow pressure of a bearing metal and make the oil-film thickness as large as possible the next designing points are needed.(i) The ratio of a radial clearance to the radius is about 5 × 10-4 .(ii) The eccentricity between journals is as large as the radial clearance.(iii) The width ratio of a main journal to the whole bearing is about 0.7.