Bearings in which the inner and outer rings are made of steel and the rolling elements are ceramics are collectively referred to as hybrid bearings. At present, there are new developments in hybrid bearings: First, ceramic materials have been used to make roller for cylindrical roller bearings, ceramic cylindrical hybrid bearings have appeared on the market; second, stainless steel (such as FAG's nitrided stainless steel Crodinur30) has been used instead of bearing steel. The inner and outer rings of the bearing are made, especially the inner ring. Since the coefficient of thermal expansion of stainless steel is 20% smaller than that of the bearing steel, naturally, at high speed, the contact stress increase due to thermal expansion of the inner ring is suppressed.
It is well known that the dmh value is a speed factor that expresses the high-speed performance of a rolling bearing (dm is the average diameter of the inner and outer rings of the rolling bearing, in mm; h is the rotational speed of the bearing, in units of r/min). The high-speed performance of angular contact ball bearings is not only related to the contact angle, diameter and material of the ball, but also closely related to the lubrication of the bearing. At present, the rolling bearing has three methods: grease lubrication, oil mist lubrication and oil and gas lubrication. Among them, although oil mist lubrication works well, it pollutes the environment and endangers the health of workers. It has been rarely used abroad.