Recently, wheel separation accidents in vehicles such as trucks and buses have drawn a social concern. Explications of their causes and adequate practices of countermeasures for them have been seriously required. In relation to this issue, the authors have taken notice of subjects which are concerned in bolted joints at wheels and are especially trying to study the pressure distribution at the bearing surfaces of nuts. This report deals with this subject about a nut with a spherical bearing surface. Considerations are based on numerical results derived from finite-element-analyses. Feature of the pressure distribution and equivalent stress distributions on bearing surface by this profile are mainly discussed, and concerning this issue some other information is presented.
