The basic rating life of spindle bearings: The basic rating life L10 and L10h are calculated by the following formula: L10 106 revolutions The basic rating life is in million revolutions, which refers to the life that 90% of a large number of identical bearings reach or exceed before fatigue occurs for the first time C kN basic dynamic load rating P kN equivalent dynamic load of centripetal and NTN thrust bearings p life index; roller bearings: p u003d 10/3 ball bearings: p u003d 3L10h h basic rating life in hours according to the definition of L10 n min1 speed. Equivalent dynamic bearing load The equivalent dynamic load P is a calculated value. Its size and direction are constant; it is radial load for UTE radial bearings, and axial load for thrust bearings. Using the load P to calculate the bearing life, the same rating life as the actual combined load can be obtained. P kN equivalent dynamic bearing load X radial coefficient, please refer to the dimension table or product description Fr kN bearing radial dynamic load Y axial coefficient, please refer to the dimension table or product description Fa kN bearing axial dynamic load. This calculation method is not suitable for thrust cylindrical roller bearings. Thrust cylindrical rollers are not allowed to bear combined load.