Basic load ratings
Basic dynamic load ratings
For composite materials the basic dynamic load rating C is used together with other influencing factors, to determine the basic rating life of a bearing. As a rule it represents the maximum load that a bearing can sustain at room temperature when the sliding contact surfaces are in motion. The maximum permissible load in any individual application should always be considered in relation to the desired rating life. The basic dynamic load ratings quoted in the product tables are based on the effective projected sliding surface and the specific load factor K that takes the different composite materials into consideration.
In this definition it is assumed that the load acting on a bushing or flanged bushing is purely radial and that the load acting on a thrust washer is purely axial and applied at the centre. Dynamic load conditions are essentially oscillating movements or rotations under load, but can include micro sliding under variable load (e.g. as a result of vibration) or operation under high frequency alternating loads. Where oscillating movements or rotation under load usually produce wear, the other conditions may result in fatigue.
Basic static load ratings
The basic static load rating C0 is defined as the maximum load that an SKF composite bushing, flanged bushing or thrust washer can support when stationary at room temperature without inadmissible permanent deformation of the sliding layer and jeopardizing its performance. It is assumed that the bearing is adequately supported by the associated components of the bearing arrangement. In order to fully exploit the static load rating of a bearing it is generally necessary to use shafts and housings made of high-strength materials. The basic static load rating should also be considered when bearings are dynamically loaded and are subjected to additional heavy shock loads. The total load in these cases must not exceed the basic static load rating.