Pillow block bearings are composed of the outers spherical ball bearings with double-seal and the casting pedestal(or pressed steel plate). The inside structure of the pillow block bearings is the same as deep groove ball bearings', however the outer ring of this type has the outer surface of section balls, it can be Self-aligning when fitted with concave of the bearing pedestal. Generally there are clearance between the inner bore and shaft, we must fixed the inner ring with the shaft by tip wire, eccentric sleeve or clamping sleeve, then the bearing could rotate with the shaft. The pillow block bearings are compact in structure, convenient for assembling and disassembling. They are suitable for simple support. They are often used in mining, metallurgy, agriculture, chemical, transmission machinery and other industries.