The limit dimensions of radii between bearing and boring and the exterior diameter are given in the ISO 582 and DIN 620 norm.
The exact shape and surface of the radii has not been fixed, however its trace in an axial plan should be in the interior arch of an imaginary circle, radius rs min, tangent to the ring and boring, or to the exterior cylindrical surface of the ring as shown in the following chart:
d = nominal diameter of bore
D = nominal exterior diameter
rs min. = smallest isolated dimension accepted with curve rs max. = highest isolated dimension accepted with curve