Selected problems of experimental investigation of dynamically loaded journal bearings

In the paper some problems concerning relations between external bearing loadings and critical lining stresses are described for test stand with rotating load vector. According to the standard ISO 7905/1 this type of test stand, for dynamically loaded slide bearing, is recommended as a basic research unit for material testing in a complete bearing unit. The lining stress calculation results occurred being dependent on applied calculation model. The influence of sliding surface shape and housing stiffness on bearing fatigue have been considered. The MWO-stand operational principle, standard tested half-bearing, bearing housing of rigid profile, bearing housing of edge elastic profile, distribution of radial and circumferential stress in the slide layer of the bearing bush tested in MWO stand, typical damage of the bearing tested, finite element model geometry for bush and housing are illustrated in the paper. Performed calculations revealed that neglecting the shape and dimensions of the housing in calculation model of the contemporary thin-walled multilayer bearing bushes are leading to incorrect evaluation of critical stresses leading to fatigue cracks in slide layers of the bearing tested in machines with rotary load vector. That kind of bearing alloys is not employed in highly dynamically loaded bearings of contemporary machines, especially in IC engine bearing systems.