If rolling bearings are to operate reliably they must be
adequately lubricated to prevent direct metal-to-metal
contact between the rolling elements, raceways and cages.
The lubricant also inhibits wear and protects the bearing
surfaces against corrosion. The choice of a suitable
lubricant and method of lubrication for each individual
bearing application is therefore important, as is correct maintenance.
A wide selection of greases and oils is available for the
lubrication of rolling bearings and there are also solid
lubricants, e.g. for extreme temperature conditions. The
actual choice of a lubricant depends primarily on the
operating conditions, i.e. the temperature range and speeds
as well as the influence of the surroundings.
The most favourable operating temperatures will be obtained
when the minimum amount of lubricant needed for reliable
bearing lubrication is provided. However, when the lubricant
has additional functions, such as sealing or the removal of
heat, additional amounts of lubricant may be required.
The lubricant in a bearing arrangement gradually loses its
lubricating properties as a result of mechanical work,
ageing and the build-up of contamination. It is therefore
necessary for grease to be replenished or renewed and for
oil to be filtered and changed at regular intervals.
The information and recommendations in this section relate to
bearings without integral seals or shields. SKF bearings and bearing units with integral seals and
shields on both sides are supplied greased. Information
about the greases used by SKF as standard for these products
can be found in the relevant product sections together with
a brief description of the performance data.
The service life of the grease in sealed bearings most often
exceeds bearing life so that, with some exceptions, no
provision is made for the relubrication of these bearings.
Differences in the lubricating properties of seemingly
identical lubricants - particularly grease - produced at
different locations can exist. Therefore, SKF cannot accept
liability for any lubricant or its performance. The user is
therefore advised to specify lubricant properties in detail
so as to obtain the most suitable lubricant for the application.