Spherical Roller Thrust Bearings are separable single direction acting axial bearings (see sketch below).
NKE Spherical Thrust bearings are manufacttured to the standard boundary dimensions DIN 728 General.

Spherical roller thrust bearings are self-aligning as their spherical rollers run on the sphered raceways of shaft and housing washers. Therefore they are well able to accommodate errors of misalignment and some shaft bending in an optimum way.
Spherical roller thrust bearings transmit forces via a contact angle towards the centre axis. Thus, they are able to accommodate some radial forces along with high axial loads.
But, it must be considered that the acting radial forces must not exceed approximately 55 % of the applied axial forces.

NKE spherical roller thrust bearings are produced to normal tolerance class (PN) as standard.
Detailed tolerance values available on request

Misallignment

Spherical Roller Thrust Bearings are optimum to compensate for misalignments.
The permissible amount of misalignment from the centre position however, is dependant on both the bearing series and the applied loading.

Under normal operating conditions, such as a rotating shaft washer and permanent misalignment the, following values may be assumed:

Cages

Small and medium size NKE spherical roller thrust bearings are available with either solid brass cages (suffix M) or pressed steel cages (suffix J).
Large spherical roller thrust bearings are produced with solid brass cages (suffix M) as standard.

Minimum load

All Spherical roller thrust bearings require a certain minimum axial load to perform effectively.
To prevent excessive sliding friction, the minimum axial load applied should be over 5 %
of the axial bearing dynamic load rating Ca.

Where such a minimum load is not achieved, the load must be increased by effective measures, (i.e. preloading the bearing), using spring washers or springs etc.

Lubrication

Oil lubrication is preferred for spherical roller thrust bearings.

Grease lubrication is adequate only for applications where low loads and low speeds occur.
Particular attention must be made to ensure a sufficient grease supply to the contacting areas between the roller ends and guide flange. Frequent re - lubrication is necessary.

It must be considered that the recommended speed limits for grease lubricated spherical roller thrust bearings applies only to horizontal bearing arrangements. In the case of vertical arranged spherical roller thrust bearings, these values must be reduced by 50 %.

Abutment and fillet dimensions

In the case of spherical roller thrust bearings, an effective support of both bearing washers is necessary.

The bearing washer must contact adjacent parts with their face sides only.
The fillet radii of bearing corners must not touch the shoulder fillet radii of the shaft or the housing shoulders.
Therefore, the largest fillet radius must be smaller than the minimum fillet dimension of the bearing rings.

To avoid any contact between rollers and the housing with high misalignments, the housing bore must be designed according to the recommendations. Further information can be made available on request.

All information courtesy and copyright NKE Bearings Austria www.nke.at