In bearings of this type, the cylindrical rollers are in linear contact with the raceways. They have a high radial load capacity and are suitable for high speeds.
There are different types designated as NU, NJ, NUP, N, NF (for single-row bearings), NNU, and
NN (for double-row bearings depending on the design or absence of side ribs). The outer and inner rings of all types are separable.
Some cylindrical roller bearings have no ribs on either the inner or outer ring, so the rings can move axially relative to each other. These can be used as free-end bearings. Cylindrical roller bearings,
in which either the inner or outer rings has two ribs and the other ring has one, are capable of
taking some axial load in one direction Double-row cylindrical roller bearings have high radial
rigidity and are used primarily for precision machine tools.
Pressed steel or machined brass cages are generally used, but sometimes molded polyamide cages are also used. Depending on the existence of ribs on their rings, Cylindrical Roller Bearings are classified into the following types:
Types NU, N, NNU, and NN are suitable as free-end bearings. Types NJ and NF can sustain limited axial loads in one direction. Types NH and NUP can be used as fixed-end bearings.
NH-type cylindrical roller bearings consist of the NJ-type cylindrical roller bearings and HJ-type L-shaped thrust collars.
The inner ring loose rib of an NUP-type cylindrical roller bearing should be mounted so that the marked side is on the outside.