Needle bearings are roller bearings with cylindrical rollers, which are thin and long relative to their diameter. Such rollers are called needle rollers. Despite having a smaller 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 length of the roller), so The radial structure is compact, and when the inner diameter and load capacity are the same as other types of bearings, the outer diameter is the smallest, especially suitable for the support structure with limited radial installation size.
Depending on the application, a bearing without an inner ring or a needle roller and cage assembly can be selected. At this time, the surface of the journal and the surface of the housing hole matched with the bearing are directly used as the inner and outer rolling surfaces of the bearing. In order to ensure the load capacity and running performance As with the bearing with ring, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or housing hole should be similar to the raceway of the bearing ring. This type of bearing can only bear radial loads.