Spherical roller bearings are self-aligning roller bearings. They are double row, self-retaining units comprising solid outer rings with a concave raceway, inner rings with a cylindrical or tapered bore and ball and cage assemblies. Therefore, the bearings are self-aligning and insensitive to misalignment of the shaft relative to the housing, which can be caused, for example, by shaft deflection. The allowable aligning angle ranges from 1°to 2.5°. It is especially suitable for scenarios where the rotating shaft has the possibility of inclination or flexible deformation. Self-aligning roller bearings are designed to accommodate heavy radial loads, as well as heavy axial loads in both directions.