The conformity is the ratio between radius of curvature of a race and the ball diameter. For geometric reasons, the value has to be larger than 0.5. The values used for the calculation of tables in ISO 281 are fi=fe=0.52 for radial ball bearings and fi=fe=0.535 for thrust ball bearings as stated in ( ISO/TR 1281-1, 2008).
According to (ISO/TS 16281, 2008) usual values are fi=0.52 and fe=0.53 for radial ball bearings and fi=fe=0.54 for thrust ball bearings. (ISO 76, 2006) also uses fi=fe=0.54 for thrust ball bearings.
For spherical or barrel roller bearings values of fi= fe=0.5 should be used. Here the diameter of the outer race de is used as reference.
According to (ISO 281, 2007) and (ISO 76, 2006) a larger conformity reduces the load capacity and therefore a reduction of fc is required, but a smaller conformity does “not necessarily increase the load-carrying ability”. Therefore, the software allows to enter a limit for the conformity used for the calculation of load capacity. See the -button behind the bearing type for ball bearings.
For spherical ball bearings, the diameter of outer race de is used as reference for fe. So fe=0.5 should be used as default. The -button allows to enter the radii and to optionally adjust the pitch diameter Dpw so that the outer race is a sphere with fe=0.5
Using the -button behind the input field, the conformity can be calculated from a given radius. Ensure that you input the correct roller and pitch diameter before.