Bearings whether rolling ball or roller are intended to support and guide using the least amount of friction while rotating or oscillating as elements in machine operation. Bearings are used to transfer loads between machine components providing high precision, low friction and the least amount of noise emissions. SKF Bearings provide a very cost effective means by which to transfer loads, while supporting machine components and conform to ISO standards.
The two standard types of rolling elements are ball and rollers.
The two basic types of rolling elements are the determinate as to what the bearing function is. Ball bearing uses balls, roller bearings use rollers. Ball and rollers make contact differently with the raceways.
- Ball → ball bearing
- Roller → roller bearing
Fig.1 Balls make point contact with the ring raceways
As the load increases acting on the bearing, the contact point forms into an elliptical area. This small point of contact allows for lower rolling friction. Because of the small contact point, SKF ball bearings can easily accommodate higher speeds as well. Conversely, SKF ball bearings will have limits for load-carrying capacity versus SKF roller bearings.
Fig. 2 Rollers make line contact with the ring raceways
When there are higher loads acting on the roller bearing, the contact line will become rectangular in shape. In SKF roller bearings with a larger contact area along the line they are able to carry heavier loads. As with the greater surface area the roller is generally operating at lower speeds than ball bearings of similar size.
SKF Radial and Thrust bearings
SKF rolling bearings can be classified based on the direction of the applied loads they are needed to accommodate. For example SKF radial ball bearings are used when loads act primarily perpendicular to the shaft. Some radial bearings support pure radial loads only, most however can additionally accommodate some axial loads in one direction and, in some cases, both directions. In the below (fig. 3). You see a roller bearing designed for axial load or loads parallel to the shaft and then a radial ball bearing used to accommodate radial loads or loads perpendicular to the shaft.
Fig. 3 Roller bearing designed for axial load or loads parallel to the shaft
Thrust bearings
SKF thrust ball bearings accommodate loads that act predominantly along the axis of the shaft or parallel to the shaft. Various types of SKF thrust bearings will support pure axial loads in one or both directions (fig. 4)
Fig. 4 SKF thrust bearings will support axial loads in one or both directions
Other SKF thrust bearings can accommodate radial loads (combined loads, fig. 5).
Fig. 5 Сombined loads
Thrust bearings cannot accommodate speeds as high as similar sized radial bearings.
Symbols used by SKF and the rest of the bearing industry are in accordance with ISO standards. The most common symbols are:
- d Bore diameter
- D Outside diameter
- B Bearing width
- H Bearing height
- r Chamfer dimension
- α Contact angle
SKF Bearing manufactures several bearing types enclosed with seals or shields on one or both sides. SKF Bearings enclosed on both sides are factory-filled with grease. Sealed ball bearings provide an economic, space-saving solution compared to other added machine component seals.
This article serves to introduce you to bearing basics. For further information please contact us a info@pibsales.com.