What is the difference between needle roller bearing and cylindrical bearing

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, its inner diameter size and load capacity are the same as other types of bearings, and its outer diameter is small, which is especially suitable for the support results with limited radial installation size. According to different application occasions, the bearing without inner ring or needle roller and cage assembly can be selected. 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 that the load capacity and operating performance are the same as those of the bearing with ferrule, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or outer shell hole shall be similar to that of the raceway of the bearing ferrule. This kind of bearing can only bear radial load.