Cylindrical rollers and raceways are linear contact bearings. Load capacity is strong and mainly bear radial load. The friction between the rolling element and the retaining edge of the ring is small, suitable for high-speed rotation. According to whether the ring has ribs or not, it 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. This type bearing has a separable inner ring and outer ring.