The outer ring raceway of self-aligning ball bearings forms a sphericar surface whose center is common to the bearing center. The inner ring of the bearing has two raceway. The ball,cage,and inner ring of these bearings are capable of a shifting in order to compensate for a certain degree of misalignment with the outer ring.
As a result,the bearing is able to align itself and compensate for shaft/housing finishing unevenness,bearing fitting error,and other sources of misalignment