XLB Spherical Ball Bearing 1201

Self-aligning ball bearing:
Self aligning ball bearings are suitable for applications where misalignment can arise from errors in mounting or shaft deflection. The steel balls, cage, and inner ring can rotate freely at a certain angle, as it is stated that the bearings have self-aligning features. Accordingly, misalignment of the bearing shaft due to the machining and installation of the shaft and housing will be automatically adjusted.

Physical Characteristics of Self Aligning Ball Bearings
The self-aligning ball bearing has two rows of balls.
A common concave sphered raceway in the outer ring.
The center of whose curvature meets that of the bearing itself, so that the inner ring, balls and cage continue to rotate.
The self-aligning ball bearing with a tapered bore can easily be fit to the shaft with an adapter assembly.
These bearings come in internal and external types. Internal bearings have an outer-ring ball groove ground to a spherical surface. This surface makes these auto bearings insensitive to misalignment, but increases raceway contact stresses, which cuts load capacity.
Externally self-aligning bearings have a spherical surface on the outside of the outer ring, which matches a concave spherical housing. External bearings have better load capacity than internal, but demand greater radial space.