The cylindrical roller and raceway are line contact bearings. They have large load capacity and mainly bear radial loads. The friction between the rolling element and the rib of the ferrule is small, which is suitable for high-speed rotation. According to whether the ferrule has ribs or not, they can be divided into single-row cylindrical roller bearings such as NU, NJ, NUP, N, NF, and double-row cylindrical roller bearings such as NNU and NN.