The Characteristics of Surface Roughness Important to Gear and Rolling Bearing Problems,

The role of surface roughness in rolling and rolling and sliding contacts is examined. Examples of the influence of roughness are drawn from helicopter transmission and rolling bearing research at Imperial College, London. The important influence of geometry and roughness in tribological problems has been accepted for many years but only limited progress has been made in understanding the exact mechanisms involved and incorporating this knowledge into surface finishing processes designed to improve performance. This papers presents an approach to surface topography measurement and analysis which allows many of these problems to be examined in great detail. Examples of the approach are presented for several problems to be examined in great detail. Examples of the approach are presented for several tribological problems including dimensional tolerance, rolling contact noise, and fatigue life, and in each case the character of the important range and size of surface roughness features is identified in terms of its influence on the specific problem under examination.