An innovation in lubrication, developed and manufactured by SKF, is being introduced to protect bearings that are used in particularly demanding applications, in areas where they cannot easily be relubricated, or where high levels of contamination may be present. Called Solid Oil, the technology is contained within the normal bearing envelope and has no negative impact on performance or functionality; yet, depending on the application, it can significantly prolong operating life.
Bearings equipped with Solid Oil technology are essentially sealed for life, using a conventional cage and rolling element arrangement that incorporates a specially developed oil-impregnated polymer material. This completely fills the internal voids within each bearing, leaving a narrow gap between the rolling elements and raceways. The micro-porous structure of the polymer material holds up to four times more oil than a conventional grease-filled bearing, and allows oil to be released gradually around the moving internal surfaces to ensure uniform and consistent lubrication for the operating life of the bearing.
This construction offers a number of important benefits over conventional bearings. In particular, it enables oil to be dispersed evenly over the bearing surfaces regardless of operating temperature. For example, at low temperatures a Solid Oil bearing has extremely low start-up torque, compared with competing grease-filled bearings; similarly, as operating temperatures rise, increasing the viscosity of the oil, so the lubricant expands and is pushed outwards from the polymer layer to match the increased requirement for lubrication of the moving surfaces. Once the bearing stops rotating, any excess oil is reabsorbed by the polymer matrix.
In addition, Solid Oil bearings are excellent for use both in areas with high levels of contaminants - as the polymer layer prevents dust, moisture and solvents from attacking the moving bearing parts - and in applications with high g-forces - the polymer layer also prevents oil from being spun from the bearing under centrifugal force.
The technology can be supplied as an option with most standard SKF bearings. Applications for Solid Oil bearings are many and varied but include printing and paper making, food processing and electronics manufacture, as well as in overhead cranes, chemical mixers and pneumatic couplings.