Angular contact ball bearings usually need to be used in pairs or sets when bearing loads, and their pairing combinations directly affect the bearing capacity, rigidity, and operational accuracy of the bearings.  

The two basic pairing combinations include the following three pairing methods.  

1. DB Back-to-Back Pairing  

This assembly increases the distance between the acting points, enabling it to withstand axial and radial loads in any direction. It offers excellent axial, radial, and moment rigidity.  

2. DF Face-to-Face Pairing  

This assembly reduces the distance between the acting points, allowing it to withstand axial and radial loads in any direction, but it has relatively lower moment load capacity. It is generally used when high alignment accuracy cannot be achieved. Face-to-face pairing may affect the permissible speed.  

3. DT Face-to-Back Pairing  

The acting vectors in this assembly are parallel, enabling it to withstand radial loads and axial loads in one direction. If axial loads in the opposite direction are present, additional bearings or bearing sets are required.