Cooling Requirements of Ball Bearings Lubricated by Glass-fiber-filled Polytetrafluoroethylene Retainers in Cold Hydrogen Gas

Experiments were performed with 40-mm-bore ball bearings operating at shaft speeds to 35 000 rpm and thrust loads to 400lbf (1780 N) in 60 degree R (33K) hydrogen gas. The minimum coolant flow rate equation developed for bearings equipped with this retainer material was similar to the equation determined in a previous study for bearings with a bronze-filled polytetrafluoroethylene (PTFE) retainer. Retainer wear rate was very low; some inner-race ball-track wear was evident for bearings that had been run for more than 7 hours.