Lubrication Characteristics of an Externally Pressurized Crosshead-Pin Bearing

摘要

Because the crosshead-pin bearing for large size two-stroke diesel engines oscillates within a small angle at a low speed and is always subject to a high downward-load, the hydrodynamic oil film is very thin. It is important to improve the load carrying capacity of the crosshead-pin bearing in the context of raising engine power in recent years. In the present study, calculations were carried out to clarify the lubrication characteristics of the crosshead-pin bearing to which an externally pressurized lubrication system was applied. Because the externally pressurized crosshead-pin bearing forms a very thick oil film at the bottom dead center, an improved hydrodynamic squeeze action is produced, thereby greatly increasing the minimum oil film thickness. Increasing the hydrostatic lift as well as extending the oil pocket pitch angle are effective means to improve the squeeze action, and thereby to increase the minimum oil film thickness.