Needle Roller Bearings (needle bearing) is a cylindrical roller with roller bearings, relative to its diameter,
roller both thin and long. This is called needle roller. Despite having a smaller cross-section,has a higher
load bearing capacity, equipped with a thin and long needle bearing roller (roller diameter D≤5mm,L / D≥2.5,
L is the length of the roller), so radial structure is compact, its diameter size and load capacity and other
types of bearings, minimum diameter, especially for radial dimensions limited support structure.