nsk 2308 C3 Self-Aligning. Wheel Bearing

Self-aligning ball bearings have two rows of balls, a common sphered raceway in the outer ring and two deep uninterrupted raceway grooves in the inner ring. They are recommended when alignment of the shaft and housing is difficult and the shaft may flex. The outer ring has a spherical raceway and its center of curvature coincides with that of the bearing: therefore, the axis of the inner ring, balls and cage can deflect to some extent around the bearing center. Since the contact angle is small, the axial load capacity is low. The permissible dynamic misalignment is approximately 0.07 to 0.12 radian (4 to 7 degrees) under normal loads. Parallel bore, open type without seals to allow for the free circulation of either oil or grease.