Yoshio Shoda

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.

Improving the Survivability of High Speed Ball Bearings under Oil Shut-off Conditions by Chemical Modification of the Surface

Oil shut-off tests were performed using 150 mm bore M50-steel ball bearings under high speed rotation conditions. This investigation demonstrated that bearings that had received chemical modification of the surface were able to delay the onset of bearing seizure after lubricant shut-off Comparing the chemically modified surface, to a conventional bearing surface, this paper describes the differences and changes in the bearing temperature rise and the cage rotation speed after oil shut-off In addition, this paper presents an analysis on the changes of rolling element motion during oil shut-off for bearings with and without surface modification. Presented at the 49th Annual Meeting in Pittsburgh, Pennsylvania May 1–5, 1994