A: The outer spherical ball bearing with a seat (pillow block bearing) is composed of a sealed outer spherical ball bearing on both sides and a cast (or stamped steel plate) bearing seat. The inner structure of a pillow block bearing is the same as a deep groove ball bearing, but the inner ring of this bearing is wider than the outer ring. The outer ring has a truncated spherical outer surface, which can be automatically adjusted to match the concave spherical surface of the bearing seat. Usually, there is a gap between the inner hole of the bearing and the shaft. The inner ring of the bearing is fixed on the shaft with a jack wire, an eccentric sleeve or an adapter sleeve, and rotates with the shaft. The bearing with compact structure, convenient for loading and unloading, perfect sealing, suitable for simple support, often used in mining, metallurgy, agriculture, chemical industry, textile, printing and dyeing, conveying machinery and so on.