It is a commonly used rolling bearing with simple structure and easy use. This kind of bearing is mainly composed of outer ring, inner ring, cylindrical roller and cage. The characteristics of cylindrical roller bearings include low friction resistance, ability to withstand high speeds, strong impact resistance, and are suitable for applications with heavy loads. The overall performance is better than deep groove ball bearings, but the cost is higher. According to different rolling elements, cylindrical roller bearings can be divided into single-row and multi-row structures. Single-row structures include N type, NU type, NJ type, NUP type and RN type. In addition, cylindrical roller bearings can also be divided into two types: ribbed and ribless. Bearings without ribs can only bear radial loads, while bearings with ribs can bear radial and axial loads.