Cylindrical roller bearings, single row

SKF single row cylindrical roller bearings are available in many designs, series and sizes.

The most common designs of single row cylindrical roller bearings are shown here.

NU design bearings

- have two integral flanges on the outer ring and no flanges on the inner ring
- can accommodate axial displacement of the shaft relative to the housing in both directions
- can be used together with an appropriate angle ring to stabilize the bearing in the axial direction (Appropriate angle rings)

N design bearings

- have two integral flanges on the inner ring and no flanges on the outer ring
- can accommodate axial displacement of the shaft relative to the housing in both directions

NJ design bearings

- have two integral flanges on the outer ring and one on the inner ring
- can accommodate axial displacement of the shaft relative to the housing in one direction only
- are used to locate the shaft axially in one direction
- can be used together with an appropriate angle ring to stabilize the bearing in the other axial direction (Appropriate angle rings)

NUP design bearings

- have two integral flanges on the outer ring and one integral flange and one non-integral flange, i.e. a loose flange ring, on the inner ring
- are used to locate the shaft axially in both directions

Inch bearings
The design of SKF inch bearings in the CRL and CRM series (product table) conforms to the metric N design. They are mainly used in the aftermarket and, therefore, SKF recommends not to use these bearings for new bearing arrangement designs.

Appropriate angle rings (thrust collars)

- are used with NU design bearings to locate the shaft axially in one direction
Angle rings should not be used on both sides of NU design bearings as this can lead to axial clamping of the rollers.
- are used with NJ design bearings to locate the shaft axially in both directions
- are made of carbon chromium steel
- are hardened and ground
- have a maximum axial run-out that is in accordance with the Normal tolerance class for the appropriate bearing
- are identified by the series designation HJ followed by the appropriate bearing dimension series and size
- are available as listed in the product table
- must be ordered separately

Reasons to design angle rings into a bearing arrangement include:

- no NJ or NUP design locating bearings in the product range
- to provide an extended inner ring seat for heavily loaded bearings in the locating position:
- full width inner ring seat of NJ design bearings with an HJ angle ring compared to NUP design bearings having a shorter inner ring and a loose flange
- to simplify design or mounting procedures