Needle bearing characteristics and uses: 
With thin and long needle bearing roller (roller diameter, length 3 to 10 times the diameter of generally not more than 5mm), so the radial structure is compact, its diameter size and load bearing capacity and other types of the same, minimum diameter, especially for radial bearing installation dimensions restricted results. Depending on different occasions, can be used without inner ring of the bearing or needle roller and cage assemblies, this time with the match of the journal bearing surface and shell holes as bearing directly on the surface, the 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, machining accuracy and surface quality should be similar to the roller bearing rings. Such bearings can only bear the radial load.