You may have seen or heard people describe plain bearings as “self-lubricating”, “non-lubricating” or “dry running”. But what does this mean? These are bearings that do not require external lubrication. In other words, no one needs to stop the equipment and relubricate its bearings with a grease gun, and for larger equipment, there is no need for oil changes or fully automatic relubrication systems. What is behind this and how do plain bearings work without lubrication? We will cover this and more in this blog post. Let’s get started.

Self-lubricating bearings and self-lubricating materials

With the continuous progress of science and technology today, mechanical technology is moving towards advanced, sophisticated and diversified trends, for example, bearings in vacuum conditions, high temperature conditions and low temperature conditions and other extreme environmental problems, its solution mainly relies on the special lubrication properties of self-lubricating bearings. Self-lubricating bearing is the rolling body, inner and outer ring raceway or cage after special material treatment, no need to add oil or grease lubricants can work properly bearings. Self-lubricating bearings from the lubrication mechanism can be divided into self-lubricating material itself to produce self-lubricating characteristics of bearings and sintered microporous material due to the nature of the self-lubricating characteristics of bearings.

Self-lubricating bearing is the rolling body, inner and outer ring raceway or cage after special material treatment, do not need to add oil or grease lubricants can work properly bearings. Self-lubricating bearings from the lubrication mechanism can be divided into self-lubricating material itself to produce self-lubricating characteristics of bearings and sintered microporous materials due to the nature of the self-lubricating characteristics of bearings.

Self-lubricating materials mainly refer to some solid lubricants. Solid lubricant particles and metal co-deposited composite coating, the coefficient of friction is very small, and the coating itself has less wear. Solid lubricants are MoS2, fluorinated graphite (CF)n, polytetrafluoroethylene (PTFE) and so on. The following is a specific description of two of the more common self-lubricating materials, polytetrafluoroethylene (PTFE) and graphite.

Self-lubricating bearings provide their own lubrication during operation without the use of grease or oil-based lubricants. Self-lubricating bearings work by immersing a lubricant into the sliding layer of the bearing. Depending on the application requirements (e.g. operating temperature), this lubricant can be liquid (oil) or solid (graphite, MoS2, lead). As the bearing operates, the lubricant is released through holes in the sliding layer, thus lubricating the bearing surface. The lubricant is evenly dispersed throughout the sliding layer, so that even if the sliding layer wears, it does not degrade the performance of the low-friction bearing. A “break-in” surface is usually included at the top of the sliding layer to provide low-friction bearing performance before the impregnated lubricant reaches the bearing surface after start-up.

How do self-lubricating bearings Flange bearings work?

What is the importance of self-lubricating bearings?

Self-lubricating bearings require low-friction bearings with excellent wear resistance to help reduce labor costs. Since many applications are difficult to maintain, they benefit from long-life components, i.e. self-lubricating bearings.

Self-lubricating bearings eliminate the need for maintenance, reduce labor costs, and extend the life of the customer’s bearing application. PTFE anti-wear bearings with steel backing for collective. Learn more about oil-free composite self-lubricating bearings, sliding bearings in more industrial applications, please contact us

Therefore, self-lubricating bearings also do not require lubrication or grease, and are therefore also called maintenance-free or grease-free bearings. An important difference is that self-lubricating bearings are not pre-greased bearings, but are referred to as pre-lubricated bearings. Pre-lubricated bearings require relubrication at some point in their service life. An example of a pre-lubricated bearing is our POM bushing low friction bearing, which is lubricated with only a small amount of grease.

Lubrication was originally associated with grease or oil, but its presence does not necessarily mean dirty fingers when handling a plain bearing. Lubrication really only means reducing friction and wear between relatively moving (machine) components or friction partners. This can be a classic grease or a solid lubricant.

Solid lubricants consist of fine particles or microscopic plates that reduce the friction between friction partners. For example, graphite, molybdenum sulfite, ceramic particles or PTFE (Teflon) are common. These are usually also part of the “liquid” lubricant. But you can also process these in solid form in plain bearings.

What is self-lubrication

By compounding a solid lubricant with a low coefficient of friction into a load-bearing substrate to reduce friction or other forms of surface damage between friction surfaces.

Solid lubricating material refers to the use of solid powder, film or some overall material to reduce the frictional wear effect between the two bearing surfaces. In the process of solid lubrication, solid lubricating materials and surrounding media to physical and chemical reaction with the friction surface to generate a solid lubricating film to reduce frictional wear.

In the field of plain bearings, there are two different types of solid lubricant bearings. Plain bearings with a sliding layer, the so-called composite plain bearings, are established here. These bearings consist of a carrier layer made of metal or fabric fibers and an internal sliding layer. While the carrier layer absorbs most of the mechanical forces, the sliding layer made of PTFE or other POM ensures low friction.

Graphite Solid Lubricated Copper Bearings, Graphite Solid Lubricated Bronze Bushing. Alternatives are plain bearings made entirely of materials embedded in these lubricating particles. These plain bearings usually consist of metallic copper. The wall thickness of composite bearings is usually thinner, while the wall thickness of metallic graphite is thicker.

Not every kind of lubrication means dirty fingers or oil in the groundwater. Solid lubricants can be integrated into plain bearings, making them largely difficult to get into the environment. Solid lubricants for metal and fabric bushings include a thin layer of PTFE or other good sliding self-lubricating coating sketched out. The disadvantage is that the layer is sensitive to mechanical loads. In composite plain bearings, the solid lubricant can be integrated directly or blended into the material. This results in a homogeneous structure. The entire wall thickness acts as a wear or sliding material.

Self-lubricating materials (also known as solid self-lubricating materials) refers to the use of solid powder, film or some integral material to reduce the frictional wear effect between the two bearing surfaces. In the process of solid lubrication, solid lubricating materials and the surrounding media to physical and chemical reaction with the friction surface to generate a solid lubricating film to reduce frictional wear. The use of solid lubricating materials to lubricate the friction section is called self-lubricating technology.

Commonly used self-lubricating bearing bushing materials: Self-lubricating composite material is a composite material with certain strength and self-lubricating properties, which is prepared by a certain process by adding solid lubricant and some additional components to metal, ceramic or non-metal as the basic components. It has the mechanical properties of the base element and the tribological properties of the solid lubricant, with excellent overall performance, suitable for working in different atmospheric environment, chemical environment, electrical environment, high temperature, low temperature, high vacuum, strong radiation and other special working conditions. Mainly divided into metal-based lubricating materials, polymer-based self-lubricating materials, inorganic non-metallic-based self-lubricating materials. At present, the commercialized solid lubricants mainly include: graphite, molybdenum disulfide, polytetrafluoroethylene, etc.

Solid lubricants are commonly used in machining, pressure machining, cutting and some special working conditions. Common applications in daily life are

Self-lubricating tool: using coating coating and other methods can coat solid lubricant on the tool surface, using ion injection and other surface treatment methods can also form a solid lubricating film on the tool surface, so that the tool has self-lubricating function; also can add solid lubricant as an additive to the tool material matrix, using the advantages of solid lubricant to form a continuous solid lubricating layer on the tool surface.

Self-lubricating bearing: mainly divided into inlay type and powder metallurgy integral sintering molding. Inlay type refers to pre-designed and processed certain holes or grooves in the metal matrix, in which the solid lubricating material is embedded, so that the two are combined into a whole, to be used as bearings, shingles or liners; powder metallurgy overall sintering self-lubricating bearings refers to the solid lubricant in the form of powder added to the metal matrix raw materials, through the press molding, sintering to form a self-lubricating composite material, to be used as bearings, shingles or liner.