The grease operating life is calculated according to Schaeffler using the mean value from given diagrams. The factor kf considering the bearing type has a range for some bearing types. It can by overwritten in the software. The factor KU can be used for additional reduction factors. The grease temperature limit is dependent on the grease. It is the temperature where no reduction in grease operating live is seen. For many standard greases it is 80°C, the default value in the software is 70°C to be conservative. The software takes into account the factor for temperature KT, the factor for loading KP and the factor for oscillation KR.
For hybrid bearings the grease operating life is increased by a factor of 3.3. A hybrid bearing is assumed if the Youngs modulus of the rolling element is larger than 270 GPa. Instead of the dynamic equivalent load P the dynamic equivalent reference load Pref is used in the calculation of grease operating life. This allows to consider pretension too. The base grease operating life is limited at 75'000h for small speed as grease life of several years is not reliable.
The result for grease operating life is just a guide value. Usually, a speed limit is also specified for greases, which has to be taken into account and which is not checked by the software.
