Calculating the axial load for bearings mounted singly or paired in tandem
When a radial load is applied to a single row tapered roller bearing, the load is transmitted from one raceway to the other at an angle to the bearing axis and an internal axial load is induced. This must be considered when calculating the equivalent bearing loads for bearing arrangements consisting of two single bearings and/or bearing pairs arranged in tandem.
The necessary equations are provided in table 1 for various bearing arrangements and load cases. The equations are only valid if the bearings are adjusted against each other to practically zero clearance, but without any preload. In the arrangements shown, bearing A is subjected to a radial load FrA and bearing B to a radial load FrB. Both FrA and FrB are always considered positive, even when they act in a direction opposite to what is shown in the figures. The radial loads act at the pressure centres of the bearings (→ distance a in the product tables).
Ka is the external axial force acting on the shaft or on the housing. Load cases 1c and 2c are also valid when Ka = 0. Values of the factor Y are listed in the product tables.