SKF double row angular contact ball bearings correspond in design to two single row angular contact ball bearings arranged back-to-back, but take up less axial space. They can accommodate radial loads as well as axial loads in both directions. They provide stiff bearing arrangements and are able to accommodate tilting moments.
The standard assortment of SKF double row angular contact ball bearings comprises bearings in the 32 A, 33 A and 33 D series.
Bearings in the 52 and 53 series are no longer available from SKF and have been replaced with 32 and 33 series bearings. With the exception of size 3200, 32 and 33 series bearings are dimensionally interchangeable with bearings in the 52 and 53 series. Size 3200 has a width of 14 mm instead of 14,3 mm.
Basic design bearings
Basic design SKF bearings (designation suffix A) have an optimized internal geometry to provide high radial and axial load carrying capacity and quiet operation. Basic design bearings that are also available capped may have recesses in the inner and outer rings
Bearings with a two-piece inner ring
- Bearings with a two-piece inner ring incorporate a large number of large balls, giving the bearing its high load carrying capacity, especially in the axial direction.
- Bearings in the 33 D series are separable, i.e. the outer ring with ball and cage assemblies can be mounted independently of the inner ring halves.
- Bearings in the 33 DNRCBM series are non-separable. They have a snap ring groove with a snap ring in the outer ring, enabling simple and space-saving axial location in the housing. Bearings in the 33 DNRCBM series have been designed specifically for centrifugal pumps, but can also be used in other applications.
SKF double row angular contact ball bearings
more information: SKF angular contact ball bearings catalogue
Cages
SKF double row angular contact ball bearings are equipped with two cages. Depending on the bearing design, series and size, the cage design varies.
| Cage type |
Snap-type, ball centred |
Snap-type, ball centred |
Snap-type, crown, ball centred |
Window-type, ball centred |
Prong-type, outer ring centred |
|---|---|---|---|---|---|
| Material |
PA66, glass fibre reinforced |
Stamped steel |
Stamped steel |
Machined brass |
Machined brass |
| Suffix | TN9 |
– |
– | M | MA |
The lubricants generally used for rolling bearings do not have a detrimental effect on cage properties. However, some synthetic oils and greases with a synthetic oil base and lubricants containing EP additives, when used at high temperatures, can have a detrimental effect on polyamide cages. For additional information about the suitability of cages, refer to Cages and Cage materials.
Sealing solutions
SKF supplies the most common basic design bearings capped with a contact seal or shield on both sides. For information about the suitability of seals or shields under various conditions, refer to Sealing solutions.
Bearings capped on both sides are lubricated for the life of the bearing and should not be washed or relubricated. The bearings are considered virtually maintenance-free. If they are to be hot mounted, an induction heater should be used. SKF does not recommend heating capped bearings above 80 °C (175 °F). However, if higher temperatures are necessary make sure that the temperature does not exceed the permissible temperature of either the seal or grease, whichever is lowest. During start-up, grease may leak at the inner ring. For bearing arrangements where this would be detrimental, special design steps must be undertaken.
related articles
- SKF explorer angular contact ball bearings
- SKF angular contact ball bearing designation system
- SKF double row angular contact ball bearing designation
Related numbers
SKF 3204 ATN9 bearings
20mm x 47mm x 20.6mm
SKF 3307 A/C3 bearings
35mm x 80mm x 34.9mm
SKF 3200 ATN9/C3 bearings
10mm x 30mm x 14mm
SKF 3202 ATN9/C3 bearings
15mm x 35mm x 15.9mm
SKF 3203 ATN9/C3 bearings
17mm x 40mm x 17.5mm
SKF 3205 A/C3 bearings
25mm x 52mm x 20.6mm
SKF 3206 A bearings
30mm x 62mm x 23.8mm
