Features of hydrodynamic calculation of highly loaded plain bearings of heavy ship’s gears

Abstract

Despite the high level of modern vessel engineering development, there are a number of unresolved design and technological problems, the most urgent of which is the issue of unification of the main components and assemblies of the vessel. At the same time, an important and unresolved task is to create a unified image of the ship’s reverse gear for the needs of the domestic civilian fleet and navy. The object of study is highly loaded bimetallic plain bearings, which are elements of the “heavy” marine reverse gears of a new generation. As part of the work, a hydrodynamic calculation that refines the parameters of the plain bearings of a highly loaded marine transmission at the stage of a prototype production is performed. The applicability of the State Standard ISO 7902 methodology to the products under consideration is assessed, as well as the approximation of the performance characteristics of bearings using interpolation of two variables function is performed. The rationale for the coverage angle and the location of the pockets for supplying lubrication of bearings taking into account the thermal and viscous properties of the oil is presented. Calculations of the parameters of the critical thickness of the lubricating layer, the maximum allowable specific load and the maximum allowable temperature of bearings are performed. Based on the results of the calculations, an additional assessment for the compliance of bearings with the requirements of State Standard ISO 7902 in terms of bearing capacity and stability parameters is carried out. The comparison of the obtained results with the data of the preliminary calculation performed at the stage of the technical project is given. It is revealed that when calculating dynamically loaded plain bearings, it is necessary to take into account a number of additional factors, namely the magnitude of the relative eccentricity and relative clearance. The risks of bearings failure in the process of dynamic loading are determined. The result of the work is the correction of the geometric parameters of the plain bearings of the marine reverse gear unit in order to increase its reliability and the overhaul interval.