Author(s)

J. Aguirrebeitia, R. Avilés, I. F. de Bustos & M. Abasolo

Abstract

This work tries to represent the general static load-carrying capacity of fourcontact- point slewing bearings under general loading. This representation is based on a generalization of Sjoväll and Rumbarger’s equations and provides an acceptance surface in the load space. This acceptance surface provides the key set of acceptance curves for the design and selection of bearings. Keywords: four contact point slewing bearing, acceptance surface, bearing selection, static load capacity. 1 Introduction Slewing bearings are large-sized bearings with many applications, such as in wind turbine generators, tower cranes vertical lathe tables... The loads acting on these bearings usually contain axial and radial forces, as well as tilting moments (see Figure 1). In the most unfavourable load case, the radial force is perpendicular to the resultant of the tilting moments. Several bearing manufacturers provide acceptance curves that allow one to determine whether or not a bearing is acceptable for a given equivalent load, calculated as a combination of the axial and radial loads. By means of a moment–axial-force diagram, this equivalent load allows a designer to obtain the maximum allowable tilting moment that the bearing can bear. This is illustrated in Figure 2. There are some variations in the form and limits of the diagram shown in Figure 2. depending on the manufacturers having experimented with or assessed the bearings themselves, or having simply copied other manufacturers’ data. Anyhow, there is always a certain ambiguity and a lack of a clear criterion in the

Keywords

four contact point slewing bearing, acceptance surface, bearingselection, static load capacity