In a cylindrical roller skf bearing in a row, the rollers are always guided between the shoulders “open” fixed one of the rings. These shoulders “open”, combined with a design and a surface finish specific faces rolls, improve lubrication, while reducing friction and, therefore, the operating temperature.

The ring shoulders with fixed and all-cage cylindrical rollers may be separated from the other ring, which facilitates the installation and dismantling, particularly when the load conditions require a fit of the two rings.

The cylindrical roller bearings in a row SKF have a strong capacity for radial load and allow high speeds. They are made of several types that differ in configuration shoulders. The most common types are the UN, N, NJ and NUP.

Type NU
The outer ring bearing type NU has two fixed shoulders, and their inner ring is without shoulder. The axial displacement of the tree compared to the level can be supported in both directions within the same rotation. The bearings are used as bearings free. For reasons of manufacturing and maintenance, it may be that both shoulders of the outer ring bearing large type NU designated by a number of design are not fixed but takes the form of rings free shoulder.

Type N
The inner ring has two shoulders fixed and the outer ring is without shoulder The axial displacement of the tree compared to the level can be supported in both directions within the same rotation. The bearings are used as bearings free.

Type NJ
The outer ring has two shoulders fixed and the inner ring a shoulder fixed These bearings therefore agree to the setting axial shaft in one direction

Type NUP
The outer ring has two shoulders fixed and the inner ring a shoulder fixed and a ring shoulder free These bearings can be used as fixed landings, ie they can be used to establish a tree axially in both meaning