Maintenance-free outer spherical ball bearing is actually a variant of deep groove ball bearing. Its outer diameter surface is spherical, which can be fitted into the corresponding concave spherical surface of the bearing seat to play a role of alignment. Maintenance-free external spherical bearings are mainly used to withstand radial and axial combined loads, which are mainly radial loads. Generally, they are not suitable to withstand axial loads alone.
Maintenance-free external spherical bearings are preferred for applications requiring simple equipment and components, such as agricultural machinery, transportation systems or construction machinery.