Utjecaj ekscentrične porivne sile na odabir statvenog kliznog ležaja

Abstract

Stern tube slide bearing of the shaft line of the ship's propulsion system causes losses during operation. Friction and material wear of the tribosystem occur. One of the reasons is the different navigating regimes of the ship, which have an influence on the formation of the velocity field on the ship's propeller. The variable velocity field defines the magnitude and the position of the thrust force. The methodology presented in this paper is based on the fact of the existence of the eccentricity of the thrust force, i.e. loads due to the action of the moment of the eccentric thrust force. Due to the changing position of the thrust force, the curvature of the elastic line of the sleeve inside the stern tube bearing, which is mostly spatial, changes. Spatial elastic line of the sleeve has an influence on the working area of the slide bearing. Therefore, the importance of a sufficient thickness of the lubricant layer for lubrication in relation to these changes was highlighted. In this paper, this is the initial criterion for the selection of materials and lubricants of the stern tube bearing. An equally important criterion would be to define the possible harmful impact of lubricant leakage with particles of bearing bush material on the ecosystem. In order to facilitate the whole process, the simplified analytical model is presented, which can be used in the initial stage of stern tube bearing selection. Such a model allows a simpler analysis of the influence of the elastic line on the condition of the stern tube bearing due to the loading by the weight of the ship's propeller and by the moment of the eccentric thrust force. The procedure for the initial selection of the stern tube bearing created by this methodological approach could have its practical application. For this reason, the paper analyzed different navigating regimes and their influence on the working area of the stern tube slide bearing. The obtained results can be useful in the selection of materials and lubricants for the stern tube bearing tribosystem.