Depending on their design, series and size, SKF needle roller bearings with machined rings are fitted with one of the cages shown in table 1.
Double row needle roller bearings with machined rings are equipped with two cage assemblies (fig. 1).
The lubricants generally used for rolling bearings do not have a detrimental effect on cage properties. However, some synthetic oils and greases with a synthetic oil base and lubricants containing EP additives, when used at high temperatures, can have a detrimental effect on polyamide cages. For additional information about the suitability of cages, refer to Cages and Cage materials.

Sealing solutions

Needle roller bearings with machined rings in the (R)NA 49 series are available with a contact seal on one (fig. 2) or both (fig. 3) sides. The NBR seals are effective at keeping the lubricant in and contaminants out of the bearing.

The inner ring of sealed bearings is 1 mm wider than the outer ring. This maintains the effectiveness of the seals and simplifies the bearing arrangements even when small axial displacements occur.

In addition to integral bearing seals, SKF also supplies an assortment of external seals that can be used for needle roller bearing arrangements. Appropriate power transmission seals are listed in the product table, when available. For information about these seals, refer to the product information, available under Seals.

Greases for capped bearings

Needle roller bearings with one or two seals are are supplied greased. They are filled with high-quality grease under clean conditions.

The relatively large quantity of grease in the bearings means they can be operated for long periods before relubrication is required. SKF recommends SKF LGWA 2 grease, if relubrication is required.

The technical specifications for the initial grease fill and the grease for relubrication are listed in table 2.

Relubrication features

Depending on the design and size, SKF supplies needle roller bearings with different features to facilitate efficient lubrication and relubrication.
All needle roller bearings with machined rings and flanges, with an outside diameter D ≥ 19 mm (F, Fw ≥ 12 mm) have an annular groove and, depending on the bearing size, one or more lubrication holes in the outer ring (fig. 4). Sealed needle roller bearings have an additional lubrication hole in the inner ring (fig. 2, fig. 3).
Double row machined needle roller bearings without flanges have an annular groove with one lubrication hole in the outer ring (fig. 5).
For single row bearings without flanges and with an inner ring, SKF supplies certain sizes with one lubrication hole in the inner ring (→ product table).
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