Needle roller bearing is a roller bearing with cylindrical rollers. The rollers are thin and long relative to its diameter. This roller is called needle roller. Although it has a small section, the bearing still has a high load bearing capacity. The needle roller bearing is 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 its inner diameter size and load capacity are the same as other types of bearings, the outer diameter is the smallest, which is especially suitable for supporting structures with limited radial installation size. Bearing or needle roller and cage assembly without inner ring can be selected according to different applications. At this time, the journal surface and shell hole surface matched with the bearing are directly used as the inner and outer rolling surfaces of the bearing. In order to ensure the same load capacity and operating performance as the bearing with ring, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or outer shell hole should be similar to the raceway of the bearing ring. This bearing can only bear radial load.
