What Are the Functions of Solid Lubricating Grease for Bearings?
Solid lubricating grease is an oil-saturated polymer matrix that completely fills the free space in bearings, encapsulating the rolling elements and cage. The polymer material has a porous structure with millions of micropores to accommodate lubricating oil. Due to the extremely small size of the pores, the oil is retained in the material through surface tension.
When the oil-saturated polymer material is pressed into the bearing, very small gaps form around the rolling elements and raceways, allowing the bearing components to rotate freely. The oil that permeates into the gaps provides excellent lubrication for the bearing from the start.
Functions of Solid Lubricating Grease
1.It provides a stable supply of lubricating oil for the bearing.
When metal surfaces (such as the raceways of the bearing) slide over the solid oil, they are covered with a uniform and consistent oil film. Then, only when the operating temperature moderately increases, the oil is pushed to the surface of the polymer matrix. This "low" oil in the polymer matrix occurs because the oil has a higher thermal expansion coefficient than the polymer matrix and because the viscosity of the oil decreases as the temperature rises. When the bearing stops operating, excess oil is reabsorbed into the polymer matrix.
2.It pre-fills more available lubricant for the bearing.
Bearings using solid lubricating grease contain 2-4 times more oil than those lubricated with traditional grease. This is because the bearing is completely filled with solid lubricating grease, whereas grease-lubricated bearings typically only fill about one-third of the free space with grease.
3.It prevents contaminants from entering.
Since solid lubricating grease completely fills the bearing cavity, it is difficult for contaminants to reach the bearing contact surfaces. In highly contaminated environments, solid lubricating grease manufacturers recommend filling the free space in the housing with appropriate grease to provide an additional protective layer.
4.No sealing is required, and no relubrication is needed.
Solid lubricating grease contains a large amount of oil and is reusable, so no relubrication is required. At the same time, solid lubricating grease bearings secure the lubricant internally, so even on vertical shafts, no seals are needed to maintain bearing lubrication. However, if the unit already includes seals, they should be retained to prevent contamination.
5.Chemical resistance and high gravity resistance.
The polymer matrix of solid lubricating grease is unaffected by most chemicals, except for organic solvents such as kerosene, which can damage the polymer matrix and remove the oil from it. Solid lubricating grease becomes an integral part of the bearing, so even under high centrifugal forces, the lubricant cannot be expelled.
