SKF inch roller bearing units are intended for grease lubrication.
Initial grease fill
SKF inch roller bearing units are filled with a mineral oil based lithium grease that contains EP additives. The initial grease fill at the factory fills the bearing completely and 40 to 50% of the free space in the housing. The technical specifications of the grease are provided in table 1. The grease provides reliable performance when operating between 95 and 230 °F. During start-up, temperatures down to –5 °F are permissible. For short periods, temperatures above 230 °F can be tolerated.
For additional information about permissible temperatures of rolling bearing greases, refer to Temperature range – the SKF traffic light concept.
SKF inch roller bearing units are typically relubricated in order to realize maximum service life. All bearing units except those in the FYRP series have a lubrication hole with a 1/8-27 NPSF thread. They are provided standard with a grease fitting AH 1/8-27 PTF. Units in the FYRP series have a 1/4-28 UNF straight thread, and are provided with a grease fitting 1/4-28 UNF.
Before relubricating, the grease fitting and the area surrounding it should be cleaned. High-pressure cleaning equipment should be avoided. During relubrication, grease should be introduced via the grease fitting while the shaft is rotating slowly. Excessive pressure and over-greasing should be avoided, otherwise the seals may be damaged.
The appropriate quantity of grease for relubrication of SKF inch roller bearing units is provided in table 4.
Greases for relubrication
To relubricate SKF inch roller bearing units, SKF recommends using SKF LGEP 2 grease, which is fully compatible with the original grease introduced at the factory. Other compatible greases such as SKF’s multi-purpose LGMT 2 and LGMT 3 greases can also be used.