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Solid Oil Bearings

Solid oil bearings are an oil-saturated polymer matrix that completely fills the free space between the rings and rolling elements in the bearing, encapsulating rolling elements and cages, the polymer material has a porous structure with millions of micropores, To accommodate lubricating oil, since the pores are very small, the oil is retained in the material by surface tension.
  • W6204-2RS1/W64F


  • W64 Suffix

Pillow block bearing unit with solid oil

What is a solid oil bearing?

What is a permanently lubricated bearing?

Solid oil bearings are an oil-saturated polymer matrix that completely fills the free space between the rings and rolling elements in the bearing, encapsulating rolling elements and cages, the polymer material has a porous structure with millions of micropores, To accommodate lubricating oil, since the pores are very small, the oil is retained in the material by surface tension.

When the oil-filled polymer material is pressed into the bearing, very small gaps are formed around the rolling elements and raceways, allowing the bearing components to rotate freely, and the oil that seeps into the gap provides good lubrication for the bearing from the start. This design has advantages over traditional lubricated oil bearings.

Which bearing manufacturer produces solid oil bearings?

Almost world-renowned brands produce solid grease bearings, NSK is called molded oil bearings, SKF is called solid oil bearings, NTN, FAG, EASIER(Solid Lubricant Bearings), TIMKEN, TKW and other brands have production of Solid grease bearings.

Solid oil bearings are designed for practical applications at moderate to high temperatures with occasional exposure to water and other contaminants. Bearings using solid oil are lubricated for life and cannot be relubricated.

Solid oil bearings inject polymer materials into the bearing in the form of a mold. The polymer material absorbs saturated lubricating oil. The polymer material forms a small gap around the rolling elements, cages and raceways so that the bearing can rotate freely.

How do solid oil bearings work?

The unique design of solid oil bearings can provide a steady supply of lubricating oil to the bearings. When a metal surface, such as a raceway in a bearing, slides over solid oil, it is covered with a uniform film of oil, and then, with only modest increases in operating temperature, the oil is pushed against the surface of the polymer matrix, polymerizing This "low oil" in the polymer matrix is because the oil has a higher coefficient of thermal expansion than the polymer matrix, and because the viscosity of the oil decreases with increasing temperature, the excess oil reabsorbs when the bearing stops running into the polymer matrix.

Solid oil prefills the bearing with more available lubricant. Solid oil bearings contain two to four times as much oil as conventional grease-lubricated bearings because the bearings are completely filled with solid oil, whereas grease-lubricated bearings typically only fill about one-third of the free space with grease.

Solid oil bearings keep out contaminants. Since the solid oil completely fills the bearing cavity, it is difficult for contaminants to reach the bearing contact surfaces. In highly polluted environments, TKW recommends filling the free space in the housing with a suitable grease to provide an additional layer of protection.

Solid oil bearings require no seals and no relubrication. Solid oil contains a large amount of oil and is reusable so relubrication is not required, also solid oil bearings hold the lubricant inside so there is no need for seals to keep the bearing lubricated even on vertical shafts however, if If the unit already contains seals, the seals should be retained to prevent contamination.

Solid oil bearings are resistant to chemicals and high gravity. Solid oil polymer matrix is unaffected by most chemicals, with the exception of organic solvents, such as kerosene, which will break down the polymer matrix and remove the oil from it. Solid oil becomes an integral part of the bearing so that the lubricant cannot escape even when subjected to high centrifugal forces.

Classification of solid oil bearings

The standard assortment of bearings with Solid Oil includes:

• Deep groove ball bearings with solid oil

• Spherical roller bearings with solid oil

• Pillow Block bearings with solid oil

• Tapered roller bearings with solid oil

• Cylindrical roller bearings with solid oil

• Self-aligning ball bearings with solid oil

structure of ball bearings with solid oil

Features and benefits of Solid Oil Bearings

· Long service life

-- An increase in operating temperature pushes the oil toward the surface of the polymer material, supporting consistent lubricant supply. During shutdown, any excess oil is re-absorbed back into the polymer material.

· Extended lubricant life

-- With Solid Oil bearings, a large amount of oil is available (two to four times more compared to conventional grease fill).

-- The Solid Oil polymer structure eliminates lubricant churning.

-- Solid Oil is a high-quality synthetic oil that resists oxidation.

· Resists washout

-- Solid Oil cannot be washed out and virtually fills all free space, limiting the amount of wet contamination that can enter the bearing.

-- Water cannot mix with the oil or Solid Oil polymer.

· Virtually eliminates lubricant leakage

-- Solid Oil retains oil in the bearing.

-- Integral bearing seals further increase the oil retention.

· Protects against the ingress of contaminants

-- Close osculation between Solid Oil and the rolling elements and raceways significantly reduces the ingress of contaminants.

-- Solid Oil provides additional support for integral bearing seals.

What are the differences and advantages between solid oil bearings and traditional grease?

In most applications, standard greases and oils provide equal amounts of lubrication to the bearings, however, in applications where relubrication of the bearings is not possible, solid oil bearings are a good solution, solid oils can also be effective In applications where high levels of contamination lead to premature bearing failure, solid oil is actually a 2-in-1 solution, providing lubrication to the bearing and an extremely effective seal by completely filling the bearing cavity.

For best performance in wet environments, it is strongly recommended to use solid oil bearings with integral contact seals whenever possible, when combined with solid oil and contact seals, the sealing capability is increased, while the solid oil acts as an axial support, preventing sealing Comes off and opens under pressure.

Application of solid oil bearings


Solid oil bearings are widely used in harsh environment and clear applications such as Food and beverage,Material handling, Mining, mineral processing and cement, pellet mill equipment, steel mill rolling mills, glass factories, boiler equipment, kiln kiln cars, dirty or wet, corrosive chemicals, very cold, strong centrifugal forces, shafts, Difficult to maintain, oscillating motion, applications with high cleanliness requirements.

Suffix of Bearings with Solid Oil

-- SKF: W64, W64F, W64L

-- NSK: L11, L12 

-- NTN: LP03


-- JNS Solid Lubricant Needle Bearings

-- FAG,KOYO, PTI are all produce Solid Oil & Solid Lubrication Bearings &Molded-Oil Bearings

Operating temperature Of Solid Oil Bearings

Temperature range: -40 to 85 C (short peaks of 100 C)

Applications of Solid Oil & Solid Lubrication Bearings &Molded-Oil Bearings

  • Agriculture

  • Chemical and Pharmaceutical

  • Food and Beverage

  • Material Handling

  • Oil and Gas

  • Packaging

  • Paper

  • Quarrying, Mining and Construction

  • Steel and Metals

  • Utilities

TKW Focuses On the Development and Manufacturing of General and Non-Standard Rolling bearings

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