The rolling Bodies of needle Roller Bearings and long cylindrical roller bearings are cylindrical. The ratio of lenghth Lw and diameter Dw(Lw/Dw)is more the 3. The difference betweer needle roller bearings and long cylindrical roller bearings Lies in that the roller diameter of long cylindrical roller bearing is more than 5mm, while that of needle roller bearings is less than 5mm. The basic structure of needle roller bearings is that they are composed of a pair of rings and a group of needle rollers. The outer ring has guide rib and oil holes.
Needle roller bearings are applicable for the elements with the radial profile dimentions subjected to restriction for its compact struture, small radial sizes and big volumn of lads. The type of bearings can generally carry radial loads and can't carry axial loads. Its limit revolution is lower.
The basic structure of long cylindrical roller bearings is that it is composed of a pair of rings, a set of cages and a group of long cylindrical rollers. The type of bearings is applicable for the ele ments with radial sizes subjected to restriction and at lower revolution and can only carry radial load. In mounting the inclination of axial line of outer ring to that of inner ring is not allowed.