Angular Contact Ball B. SKF 3309 DMA

The SKF 3309-dma angular contact ball bearing, a double-row rolling bearing with a brass cage, provides stable support for combined radial and axial loads.

This double-row angular contact ball bearing 3309-dma transmits radial forces as well as axial forces acting in both directions via angularly offset raceways. Functionally, the design corresponds to two single-row angular contact ball bearings in an O-arrangement, but requires less axial installation space. Manufactured from standard rolling-element bearing steel, the bearing has an outer diameter of 100 mm and a width of 39.7 mm. As an open design without integrated sealing washers, the construction allows for the free circulation of external lubricant.

What is the 3309-dma double-row angular contact ball bearing suitable for?

Bearings of this type are used when radial loads and axial forces acting on both sides need to be accommodated simultaneously. The bearing absorbs tilting moments and supports combined loads in both directions. Due to the standard radial bearing clearance, the rolling element arrangement has a defined operating clearance within the standard tolerance range. This design is rated for operating temperatures from –20 to +150 °C and is suitable for external lubrication systems.

What are the advantages of the brass cage in this bearing design?

The built-in brass cage guides the rolling elements in two rows with high rigidity and is characterised by good run-out properties. The material retains its mechanical stability even under demanding operating conditions and vibrations. As this is an unsealed bearing, the surrounding housing should be effectively sealed against dirt and moisture. During assembly, care must be taken to ensure that the bearing seats are correctly aligned.