Bearings usualy carry the combination of radial load and axial load,and the load conditions are varied, and the

load conditions are caried. such as the changes in the amount and so on.

         Therefore, the actual load can not be directly compared with its dynamic load rating.

          In this case, it is necessary to convert the actual load into a perceived load with definite amount and direction

 that pases the bearing center . The bearing with this perceived load shall have the same life as with actual load

and the same rotational speed.
        

  This perceived load after conversion is called the equivalent dynamiv load,indicated by p.