Ceramic Bearing Fits

When using ceramic bearings great care must be taken in the specification of each bearing to ensure the optimal fit is tailored to the suit the individual application.

Many problems can arise from the use of dissimilar materials for bearing races, shaft and housing. The material properties in each case should be taking into consideration for example differences in linear expansion coefficients in high or low temperature application can lead to premature failure of a bearing as the housing or shaft could cause the race ways to fracture.

Hybrid allow for similar race way, shaft and housing materials to be used, however, due the hardness of a ceramic ball (in majority of cases, Silicon Nitride) a lighter interference, than would be used on a standard bearing, is preferable. If a ceramic ball is clamped to hard the pressure can cause subsurface stresses in the race and lead to the spalling peeling of a race way.

In many cases a light interference or press fit such as h7/H7 shaft and housing fit should be used for ceramic and hybrid bearings, but each application differs in its fitment requirements.