Hirotoshi Aramaki

The Contact Between Rough Surfaces With Longitudinal Texture—Part I: Average Contact Pressure and Real Contact Area

This paper describes a model to study the contact between two purely longitudinally rough surfaces based on theparabolic indentor problem in elasticity. Rough surfaces are characterized with three parameters: rms roughness, autocorrelation length, and bearing area. Problems encountered by conventional roughness models are treated here. It is shown that the average contact pressure and real contact area obtained from this model agree very well with a computationally more intensive model developed by Lee (1989), up to the bulk yielding pressure

The performance of a hybrid ceramic ball bearing under high speed conditions with the under-race lubrication method

Large bore (150 mm) hybrid ceramic ball bearings and all-M50 steel bearings were tested with under-race lubrication to compare the heat generation and the temperature rise at speeds up to 2.25 million DN. Furthermore, oil shutoff tests were carried out with both bearings over 2.25 million DN. The experimental results of the heat generation for both bearings were nearly the same at an axial load of 19.6 kN. at 34.3 kN, the heat generation of the hybrid bearing was lower than that of the M50 steel bearing at low speed. The heat generation of both bearings gradually approached each other with increasing speed and became nearly equal at a speed of 15,000 rpm. The survivability of the hybrid bearing in the oil shutoff test was superior to that of the M50 bearing. These experimental results were explained by the calculation results using a computer analysis software which simulates the kinematics and the performance of ball bearings.