ESDU Tribology Series

The TRIBOLOGY Series covers methods and data for the design, analysis and selection processes associated with lubricants, lubrication, friction, wear and bearings.

General guidance is given on choosing the type of journal or thrust bearing to meet the requirements of load, speed and associated environmental and operational factors, including the level of friction expected in industrial bearings. For applications in which a film of fluid cannot be maintained between a bearing and shaft, a step-by-step procedure for the design and material selection of dry rubbing bearing is provided. Selection procedures for the choice of rolling bearings are included to assist in the initial stages of design and include guidance on such aspects as estimation of basic and adjusted life rating, choice of material and lubrication, calculation of bearing loads and load rating, selection of bearing dimensions, limiting speeds, clearance, pre-loading and misalignment. Other Items deal with calculation methods for the design and analysis of: (i) steadily loaded hydrodynamic journal bearings with axial grooves and circumferential groove including superlaminar operation and low viscosity process fluid lubrication, (ii) hydrostatic bearing design with capillary restrictor control, (iii) steadily loaded fixed-inclined-pad and off-set pivot, tilting pad, thrust bearings. The methods provide estimations of film thickness, power loss, temperature within the bearing, lubricant flow rates and other associated performance characteristics.

A Series of Items deal with contact phenomena, allowing estimation of surface and sub-surface contact stresses, deflections, contact dimensions and failure criteria for components in Hertzian concentrated elastic contacts subject to combined normal and tangential loading.

Items dealing with lubrication aspects include methods for the determination of minimum film thickness in elastohydrodynamic concentrated Hertzian contacts that occur for example in rolling bearings and gears. In such contacts the pressures within the oil are many times greater than those occurring in hydrodynamic situations and consequently changes in the lubricant viscosity and the elastic deformation of the components are highly significant. Other Items include the design of tanks for forced-circulation oil-lubrication systems, grease life estimation in rolling bearings, selection of filter rating and the selection of synthetic oils.

The estimation of equilibrium temperatures in self-contained bearing assemblies is covered in a Series of Items and includes estimation of the temperature rise, the thermal resistance of an assembly, the heat transfer coefficient and the joint conductance. Other topics include the design of crossed-flexure pivots, selection procedures for the dynamic sealing of fluids dealing with both rotary and reciprocating seals, the properties of common engineering materials, the dynamics of a simple flexible rotor supported in axial groove hydrodynamic journal bearings and the stress and lubrication characteristics of disc cams.