Design and variants

SKF supplies needle roller thrust bearings in two designs:
  • needle roller and cage thrust assemblies, AXK series (fig. 1)
  • needle roller thrust bearings with a centring flange, AXW series (fig. 2)
In applications where adjacent components cannot serve as raceways, the assemblies can be combined with bearing washers in different series (→ Bearing washers).
Needle roller and cage thrust assemblies

SKF needle roller and cage thrust assemblies in the AXK series (fig. 1) are available for shaft diameters ranging from 4 to 160 mm. They can be combined with washers in the LS, AS, GS 811 or WS 811 series (→ Bearing washers) in applications where adjacent components cannot serve as raceways. These thrust assemblies can accommodate axial loads in one direction only.

Double direction bearings

Double direction needle roller thrust bearings can accommodate axial loads in both directions. They can be created by combining two needle roller and cage thrust assemblies and two bearing washers with an intermediate washer. Depending on the design, an intermediate washer can be shaft or housing centred (fig. 3 and fig. 4).

Intermediate washers must have the same hardness and surface finish as bearing washers. SKF does not supply intermediate washers, but provides material specifications and dimensional data on request.

For additional information, refer to Design of bearing arrangements.

Needle roller thrust bearings with a centring flange

SKF needle roller thrust bearings in the AXW series (fig. 2 and fig. 5) consist of a needle roller and cage thrust assembly and a thrust washer with a centring flange. The flange facilitates mounting and accurately centres the housing washer radially (fig. 6 and fig. 7). These thrust assemblies, which accommodate axial loads in one direction only, are available for shaft diameters ranging from 10 to 50 mm.

Combined needle roller bearing arrangements

To accommodate combined radial and axial loads, needle roller thrust bearings in the AXW series can be combined with the following radial needle roller bearings:

  • drawn cup needle roller bearings with a closed end or with open ends (fig. 6)
  • needle roller bearings with machined rings (fig. 7)

These arrangements provide a cost-effective and compact solution for combined loads.

Bearing washers

SKF supplies bearing washers in different designs and series. The following series can be combined with needle roller thrust bearings:

  • LS series universal washers
  • AS series thin universal washers
  • 811 series shaft and housing washers 

Bearing washers are required in applications where adjacent machine components cannot serve as raceways.

Appropriate washers are listed in the product tables and must be ordered separately, due to the number of possible combinations.

LS series universal washers

LS series universal washers (fig. 8) are made of hardened carbon chromium bearing steel. They can be used as shaft or housing washers for needle roller thrust bearings in the AXK series and as shaft washers for bearings in the AXW series. LS series washers are available for shaft diameters ranging from 6 to 160 mm. The raceway surface is ground, while all other surfaces are turned. These washers are used for applications where accurate centring of the washers is not necessary or where low speeds are involved. The washer face opposite the side with the chamfers is the raceway surface and should face the rollers.

AS series thin universal washers

AS series thin universal washers (fig. 9) are 1 mm thick, made of spring steel and hardened. They can be used as shaft or housing washers for needle roller thrust bearings in the AXK series and as shaft washers for bearings in the AXW series. AS series washers are available for shaft diameters ranging from 4 to 160 mm. Both faces are polished and can be used as raceways. If adjacent machine components are not hardened, but have adequate stiffness and the running accuracy requirements are moderate, AS series thin universal washers can be used to provide a cost-effective bearing solution.

811 series shaft and housing washers

Shaft and housing washers are used primarily with cylindrical roller and cage thrust assemblies. However, 811 series shaft washers (prefix WS) and housing washers (prefix GS) can also be combined with needle roller and cage thrust assemblies. These washers can be used in high-speed applications where accurate centring of the bearing washers is required.

For additional information about 811 series washers, refer to Cylindrical roller thrust bearings.

Cages

Depending on their series and size, SKF needle roller thrust bearings are fitted with one of the cages shown in table 1. Bearings in the AXW series are fitted exclusively with steel cages.

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.

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