Self-aligning ball bearings 

This type of bearings has two rows of balls located between the inner and outer rings. The inner bearing element is equipped with two separate raceways, and the outer ring has one common, spherical surface. Due to this, the outer ring can deviate from the axis of the part, compensating for small skewing and sagging of the shaft. An important advantage of units of this type is their excellent speed characteristics - the best ones among all bearings based on the rolling elements. Also, these parts run quietly and make it possible to reduce vibration in mechanisms.