It is a roller bearing with cylindrical rollers that are both thin and long relative to their diameter. This type of roller is called a needle roller. Despite its smaller cross-section, the bearing still has a high load-bearing capacity. Needle roller bearings are equipped with thin and long rollers (roller diameter D≤5mm, L/D≥2.5, L is the roller length), so The radial structure is compact. When the inner diameter size and load capacity are the same as other types of bearings, the outer diameter is the smallest. It is especially suitable for support structures with limited radial installation dimensions.