Bearings with seals
Bearings are regularly used under special circumstances. It may be necessary to protect the bearings against dust, dirt and moisture. It is also possible to prevent fat loss from the bearing. Bearings can be provided with various double-sided seals for this.
Double-sided sealed bearings are maintenance-friendly. The seals eliminate the need to worry about the amount or type of grease to be used. Regreasing is also not necessary with double-sided sealed bearings. The two most common seals are the two-sided ZZ and the 2RS seal.
Bearings with a ZZ seal
The ZZ seal is a thin steel plate. It is called a non-contact seal because the cover plate does not come into contact with the inner ring. As a result, there is practically no friction, virtually no wear and therefore it is widely used and is also known as 'dust sealing'. The ZZ seal is also very suitable for high speeds and for use in environments with higher temperatures.
Bearings with a 2RS seal
The 2RS seal, which stands for Rubber Seal, is a dragging seal and covered with a rubber steel plate, the rubber lip of which drags in a groove on the inner ring of the bearing, thus providing some friction and limiting speed. Typically this is about seventy percent of the open bearing maximum speed.
The operating temperature of bearings with a 2RS seal is between -30° and +110°C. Bearings with this seal are preferably used for applications where there is moderate contamination or where a 'splash sealed' bearing is desired.