A property of precision angular contact ball bearings is that they allow the creation of groups of two or more units to obtain much higher load capacity and more rigid assembly with the same overall diameter.

The simplest form of a set is a Duplex. This is an assembly of two ball bearings together in various configurations (see below).

Duplex

Back to Back (DD)
Symmetrical arrangement;
Possibility to withstand radial axial loads in two directions;
High moment rigidity.

Face to Face (FF)
Symmetrical arrangement;
Possibility to withstand radial axial loads in two directions;
Low moment rigidity.

Tandem (T)
The bearings must be identical;
Possibility to withstand one direction axial load, only;
Requires preloading by springs.

Multiple Sets
Groups with more than two bearings can be employed whenever much higher load capacity and more rigid assembly are requested, with the same overall diameter.

Groups formed with bearings of different kinds

Duplex and Multiplex sets can be further varied by mixing the contact angles and/or different sizes or series of bearings.

The only rule governing these sets concerns tandem groups, which must be formed with identical bearings.

The main advantages, which these sets offer, are:

  • optimization of load capacity and rigidity
  • possibility to reduce bearing preload and, consequently, to increase operation speed (for example, if preloading bearings of a set have smaller contact angle than loading bearings, the set preload can be reduced without affecting the limiting axial load)
  • smaller overall dimensions of the preloading bearings.

Designation Example:

EX80 7CE3T / EX75 7CE1 DDL

Group of 3 bearings, formed by 2 EX series bearings, tandem arrangement, 80 mm bore, 25 contact angle and by 1 EX series bearing, 75mm bore, 15 contact angle, back to back.