Cylindrical roller bearings belong to the separate type bearings,whose  roller and raceway is linear contact and whose  radial load  capacity is greater applying to heavy load and shock load and high speed conditions.the mounting and dismounting of such bearings is more convenient,when the requirements of inner and outer ring interference fit ,its advantages are demonstrated .this bearing can be classified  into single-row ,double-row ,four-row cylindrical roller bearings according to the rows of rollers. In addition ,there are Cylindrical roller bearings with a full complement of  rollers and other arrangements,one of which is the most widely used --single row cylindrical roller bearing with cage.
The two arrangement of double-row cylindrical roller bearing are cylindrical bore and tapered bore.The advantages of such bearing are compact in structure,high rigidity,high carrying capacity and less defomation under loads  and so on. the characteristics are suitable for supporting  spindles of  machine tools. It is classified into NN and NNU type. NN type have two ribs on the  inner ring and the outer ring withour ribs,NNU type have two ribs on outer ring and the inner ring without ribs ,this two types bearings permit  the axial displacement of shaft relative to the housing  and are used  as  non-loacting bearing.
cylindrical roller bearings with  Full complement of rollers have two types: single-row (NCF) and double-row (NNCF) full complement of roller cylindrical roller bearings because such bearings have no cage and have larger number of rollers, their carrying capacity is large,but the high speed performance is poor,generally used in low speed and heavy load application.
The cage of cylindrical roller bearings ,when its outer diameter D¨Q400mm,generally use pressed 
steel plate (or belt) cage,when D©ƒ400mm ,use steel or brass machined solid cage;four-row cylindrical roller bearings use brass cage or pin column cage.

DOUBLE ROW CYLINDRICAL ROLLER BEARINGS  d150-190mm