duplex pairs & axial preloading

Duplex Pairs

Duplex bearings are a pair of angular contact thin section ball bearings specially ground for use as a matched set.

There are three basic mounting methods to accommodate different loading requirements:

• Back to back (DB), B-Type
• Face to face (DF), F-Type
• Tandem (DT), T-Type

A duplexed pair can be used to provide accurate shaft location, to increase capacity or to increase stiffness of the bearing assembly. A duplex pair of thin section ball bearings is ground so that when mounting using recommended fits, there will be no internal clearance in the bearings. 

Back to Back (DB) B-Type	Face to Face (DF) F-Type	Tandem (DT) T-Type
Heavy radial loads Combined thrust and radial loads Reversing thrust load Excellent rigidity Moment loads	Heavy radial loads Combined thrust and radial loads Reversing thrust load Moment loads	High one-direction thrust loads Minimum axial shaft deflection Heavy radial loads

Axial Preloading

Standard duplex bearings are ground so that there will be a light axial preload induced on the bearing at nominal conditions. In some applications increased bearing stiffness may be required. In these cases the duplex grinding can be done such that a heavier axial load is induced in the mounted bearing. This load can be increased or decreased to meet the requirements of a particular application.