The aligning roller bearing is a ball bearing with a drum roller between the inner ring with two raceways and the outer ring with a spherical raceway. The aligning roller bearing has two rows of rollers, which mainly bear radial load and can also bear axial load in either direction. It has high radial load capacity, especially being suitable for working under heavy load or vibration load, but it can not bear pure axial load. This kind of bearing outer ring raceway is spherical, so it has good centering performance and can compensate coaxiality error. Self-aligning roller bearing press roller cross section shape is divided into symmetric form spherical roller and asymmetric form spherical roller two kinds of different structure. Asymmetric spherical roller bearings belong to the early products, which are used primarily for the host service. When a new design became, the host is rarely choose symmetric spherical roller bearing. The internal structure is able to bear a greater axial load after comprehensive improvement design and parameter optimization, compared with the early production of spherical roller bearings. The bearing operating temperature is low, so it can adapt to the requirement of high speed. There are two types of C type and CA type according to the differences of the inner ring with and without baffles. The C type bearing is characterized by the inner ring with no baffles and the use of steel plate ramming cage. The characteristic of CA type trarian bearings is that both sides of inner ring have baffles and the body holder is used.