Advances in high-speed rolling-element bearings

The research program begun by NASA in 1959 in order to investigate the projected temperature and speed requirements of large bore ball and roller bearings was expanded in the 1970s to include tapered roller and small bore bearings. In the course of the program, bearing speeds as high as 3 million DN and 2.4 million DN, respectively, were achieved for ball and tapered roller bearings with fatigue lives exceeding those common in commercial aircraft. The computer analysis of rolling element bearings operation have yielded reasonably accurate performance predictions for speeds up to 3 million DN. It was found that under-race bearing lubrication improved operational performance over that achieved with conventional jet lubrication methods at high bearing speeds.