Hybrid ceramic bearing refers to a rolling bearing in which the ring is made of bearing steel or special metal materials (stainless steel, high-speed tool steel or nickel base metal), and only the rolling element is made of silicon nitride. Hybrid ceramic bearings are used in ultra precision bearing configurations and require the bearings to produce the lowest friction and heat. Ultra precision angular contact ball bearings and cylindrical roller bearings are most suitable for such applications. For very high speed applications, the use of hybrid ceramic bearings is the best choice.
When calculating the rated life of hybrid ceramic bearings, the same life value as steel rolling element bearings can be used. The hardness and stiffness of ceramic rolling element in hybrid ceramic bearing are much higher than that of steel rolling element. Although the increase of hardness and stiffness will produce higher contact stress between ceramic rolling element and steel raceway, field experience and laboratory tests show that the same rated life can be used for both bearing types.
A large number of experience and tests show that in typical machine tool applications, the service life of hybrid ceramic bearings is significantly longer than that of steel rolling element bearings. The longer service life of hybrid ceramic bearings is due to the hardness, low density and surface finish of their rolling elements. Low density minimizes the internal load generated by centrifugal force and inertial force; The increase of hardness makes the rolling element more wear-resistant; The surface finish optimizes the lubrication effect of the bearing.
Compared with steel rolling elements, the lower density of silicon nitride rolling elements will reduce the internal centrifugal force. Combined with its low friction coefficient, the bearing temperature will be significantly reduced at high speed. Lower temperature operation will prolong the service life of bearings and lubricants.
Hybrid ceramic bearings have the following advantages:
● higher stiffness
● higher speed performance
● smaller centrifugal and inertial forces in the bearing
● the rolling contact stress of the outer ring at high speed is reduced to the greatest extent
● less friction heat
● lower energy loss
● longer bearing and grease life
● when subjected to frequent quick start and stop, it is not easy to slip, scratch and cage damage
● less sensitive to the temperature difference in the bearing
● higher preload / clearance control accuracy