Needle roller bearings (needle bearing) with cylindrical roller bearings, relative to its diameter, roller is fine and long. This is called needle roller. Although with a smaller cross-section bearing still had high load bearing capacity, needle roller bearing with thin and long roller (roller diameter D is less than or equal to 5mm, L / D is greater than or equal to 2.5, l is the length of the roller), so the radial structure is compact, the diameter size and load capacity and other types of bearings are the same, minimum diameter, especially on the radial installation size restricted supporting structure.
According to different occasions, can choose or needle roller bearings without inner ring and cage assembly. At this time with the matched bearing shaft neck surface and the surface of shell holes directly as a bearing inner and outer rolling surface, in order to ensure that the load capacity and operating performance and have the same ring bearing, shaft or housing holes roll surface hardness and machining accuracy and surface quality should be and bearing ring raceway and similar. This kind of bearing only can bear radial load.
