Needle bearings are roller bearings with cylindrical rollers. Relative to their diameter, the rollers are thin and long. This roller is called a needle roller. Although it has a small 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 those of other types of bearings, the outer diameter is the smallest. It is especially suitable for support structures with limited radial installation dimensions.
Depending on the application, a bearing or needle roller and cage assembly without an inner ring can be selected. At this time, the journal surface and the housing hole surface that match 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 bearings with rings, the hardness, machining accuracy and surface quality of the surface of the shaft or housing hole raceway should be similar to those of the bearing raceway. This type of bearing can only support radial loads.