The Performance of a High-Speed Ball Thrust Bearing Using Silicon Nitride Balls

A 35-mm bore angular contact ball bearing having M50 tool steel races and hot pressed silicon nitride balls was tested at speeds to 71,500 rpm (2.5-million DN). The bearing ran smoothly throughout 32 hr of accumulated time. Heat generation was 10 to 20 percent lower than that of a comparable bearing with steel balls, and the silicon nitride bearing began to skid at lower axial loads. The silicon nitride balls and steel raceways were in excellent condition after the test.