Needle roller bearings (needle bearing) with cylindrical roller is a roller bearing, relative to its diameter, roller both thin and long. This is called needle roller. Despite the smaller cross section, has a higher load bearing capacity, with thin and long needle bearing roller (roller diameter D ≤ 5mm, L / D ≥ 2.5, L the length of the roller), therefore radial structure is compact, the diameter size and load capacity and other types of bearings, minimum diameter, especially for the radial bearing mounting dimensions restricted results.
Depending on different occasions, can be used without inner ring of the bearing or needle roller and cage assembly, this time to match the journal and the bearing surface and the shell holes as bearing directly on the surface of the inner and outer rolling surface, in order to ensure the load capacity and operating performance and a ring bearing the same shaft or housing bore raceway surface hardness, machining accuracy and surface quality should be similar to the roller bearing rings. Such bearings can only bear radial load.