Table of contents 



Schaeffler Noise Index

The Schaeffler Noise Index (SGI) has been developed as a new feature for comparing the noise level of different bearing types and series. As a result, a noise evaluation of rolling bearings can now be carried out for the first time.

The SGI value is based on the maximum permissible noise level of a bearing in accordance with internal standards, which is calculated on the basis of ISO 15242. In order that different bearing types and series can be compared, the SGI value is plotted against the basic static load rating C0.

This permits direct comparisons between bearings with the same load carrying capacity. The upper limit value is given in each of the diagrams. This means that the average noise level of the bearings is lower than illustrated in the diagram.

The Schaeffler Noise Index is an additional performance characteristic in the selection of bearings for noise-sensitive applications. The specific suitability of a bearing for an application in terms of installation space, load carrying capacity or speed limit for example, must be checked independently of this.

Until now, the Noise Index has only been available for the main series of radial deep groove ball bearings, radial angular contact ball bearings, tapered roller bearings and cylindrical roller bearings. Additional bearing types and series will be updated and introduced in subsequent publications.

Example of Noise Index calculation

If the requisite basic load rating is known for an application, the bearing arrangement can also be designed using the Noise Index as an additional performance characteristic. If the requisite basic static load rating is C0 = 20 300 N for example, various ball bearings are available with a different SGI value ➤ Figure. As a result, the calculation can be carried out for the bearing application using the smallest SGI value. Bearings of Generation C offer a particular advantage here.

Example: comparison of deep groove ball bearings using the Schaeffler Noise Index

SGI =  Schaeffler Noise Index

C0 =  basic static load rating

=  standard series 62

=  series 62..-C(Generation C)