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Preload

Single bearings
Deep groove bearings at higher speed have to be preloaded in axial direction.
For single bearings adjusting springs are used.
The minimum spring load for your application can be calculated by GMN. Please contact our

Matched deep groove ball bearings
In many cases, bearing applications demand higher axial or radial capacity and smaller bearing dimensions or higher rigidity or a certain range of axial play.
Such requirements can be met by matched bearings.Only bearings from the same series and same dimension can be matched.

Universal matching
By universal matching single bearings can be assembled to DF, DB or DT configuration.
Bearings with the same kind of matching (e.g. universal matching with same axial play, without axial play or with same preload) can be interchanged within their respective group.
When mounting universal matched bearings in the DT arrangement, with or without axial play or with preload the axial load is equally distributed.

Universal matched bearings from the same type of matching can be combined to form larger groups in the DF/DT arrangement or DB/DT arrangement with more than two bearings if required.
Universal matching takes place with a measured load or a preload as shown in the chart below.

When mounting universal matched bearings the marking etching on the rings (type designation / ) must be noted according to the illustrations. .

Universal matching with axial play. Symbol DUA.
The bearings are prepared in such a way that with inner and outer rings locked together in DF or DB arrangement, a certain axial play is included.
As the magnitude of the axial play depends on the operating conditions, the axial play must be specified for each individual application.
For example with axial play 40 to 60 microns, the symbol reads DUA 40.60

Universal matching without axial play. Symbol DUO.
The bearings are prepared in such a way, that when inner and outer rings are locked together in DF or DB arrangement, there is no axial play in the bearing set.

Universal matching with preload. Symbol DUV.
When a rigid bearing arrangement, free from play, is required, a matching of bearings with preload is used.
Bearings matched with preload have the advantage that under the effect of an external load only a small elastic deformation takes place, compared to unmatched bearing pairs or single bearings.
The bearings are prepared in a way that if inner and outer rings are locked together they are under the effect of a preload.
The preload has to be considered as an additional axial load in the life time calculation.

The preload of DUV matched bearings is 2% of the dynamic load rating, however the max is 300N.
A preload can be specified to suit the customer's requirements.

Measuring loads and tolerances

Measuring loads and preload

Type of maching	Measuring load
DF DB DT DUA     DUO	d   3 - 7  mm 8 - 15 mm 15 - 30 mm über 30 mm	12 N 22 N 32 N 50 N
DUV Preload meeting the individual application	2% of the dynamic carrying number, however max. 300 N

 

Width tolerance of matched deep groove bearings

Type of matching	Width tolerance B1  [µm]
DF    DB DT	0 - 250
DUA    DUO  DUV	0 - 500