Plain Bearings in Marine Applications

Abstract

Abstract Plain bearings are used in reciprocating and rotating machines to transmit loads through the engine structure, permitting conversion and transfer of motion/power. Internal combustion engines are extensively used in marine propulsion systems and utilize plain bearings as main bearings to retain the crankshaft within the engine crankcase, big‐end bearings to link the connecting rod to the crank pin, and small‐end bushes to link the piston to the connecting rod. The power from the engine is transmitted to the ship propeller via a propeller shaft that is supported by a plain bearing bush commonly known as the stern tube bearing . Plain bearings rely on a complex tribological system, and safe operation of these critical components depends on factors such as physical, mechanical, and tribological properties of the housing, journal, and bearing; tribological properties of the lubricating oil; and the operating parameters of the engine. If something goes wrong within the engine, for example, deterioration of the lubrication system, the bearings will absorb the damage and reduce the risk of the damage to other critical and expensive engine components such as the crankshaft. Plain bearings are designed to be a modular component, so it is possible to replace or upgrade plain bearings if damage is noticed during regular service intervals. This article is a brief overview of bearing construction, operation, possible causes of bearing damage, bearing materials, and current development trends in bearing technology. The article is concluded with some tribological results of a new lead‐free multilayer tin–copper overlay material developed specifically for marine engines.