Spherical roller bearing is a kind of bearing equipped with drum-rollers between inner ring (with two raceways) and outer ring (with its raceway is spherical), which has two row spherical roller. Its aligning feature could compensate error for shaft deformation and bearing housing misalignment. Roller and raceway for such kind of bearign is line contact, which could bear higher radial load and two-way axial load. As different bearing sizes, the angle misalignment is also different with the max value could not exceed 2.5°. Spherical roller bearing has two row roller, mainly used to withstand radial load, and to bear small amount of axial load. Higher radial load capacity is especially suitable for heavy and vabriating load, while could not bear pure axial load.