Is a roller bearing with cylindrical roller, relative to its diameter, the roller is fine and long. This is called needle roller. Although it has a small section, the load bearing capacity of the bearing is still high, with thin and long needle bearing roller (roller diameter of D = 5mm, L/D = 2.5, L roller length), so the radial structure is compact, the minimum diameter of the diameter and load capacity and other types of bearings, bearing the same, especially for the structure in radial installation size limited. According to the use of different occasions, can choose the inner ring of the bearing or needle roller and cage assembly, the shaft neck surface and the surface of shell holes matched with a bearing directly as the bearing inner and outer rolling surface, in order to ensure the load capacity and operating performance and have the same ring bearing, shaft or housing bore raceway surface hardness the machining precision and the surface quality of bearing ring raceway and similar. Such bearings can only bear radial loads.