Self-lubricating Bushing – What are the options

As a leading manufacturer of bronze bushings, we often receive requests for a variety of product types. One common product request is for self-lubricating bushings. This term can refer to many different products. This article should help you better define your requirements.

Self-Lubricating Bronze Bushings
The term “self-lubricating bushing” is a broad term for a variety of self-lubricating products. In a general sense, it refers to bronze bushings that do not require artificial lubrication. There are several methods that can be used to achieve this characteristic, and the following are the two most common methods

Oil Immersion Method – These are bronze bushings manufactured by a powder metallurgical process. In the final stage, the bushings are immersed in oil. These are also known as sintered bushings or named by SAE 841.

Self-Lubricating Bushings
Self-Lubricating Graphite Plugged Bronze Bushings
Plugged Graphite Bushing – This product is a cast bronze bushing that is milled and plugged with a graphite plug. The graphite acts as a lubricant. These products are used in applications where the performance of oil-impregnated bushings is not sufficient. Examples of this are high temperature applications or applications with heavy load requirements.

As you can see, these are two completely different product types. From the way they are manufactured to their proper use. However, many times they are referred to by the same name. If you are not sure which product type is right for your specific application, please contact our sales department at the link below.

Self-lubricating Bearings Type

Self-lubricating Bearings Bushing from the product structure is divided into solid inlay bearing, composite bearing, oil-free bushing, new single lubrication material.
Solid inlay bearings
Common is the solid lubrication material graphite (black lead), polytetrafluoroethylene (PTFE), molybdenum disulfide, etc. using the inlay process buried in high force brass, tin bronze, aluminum bronze, cast iron or GCr15 and other alloy materials. It breaks through the limitations of general sliding bearings relying on oil film lubrication. In the process of use, the solid lubrication is made to rub with the shaft through frictional heat, forming the excellent condition of oil and powder coexisting lubrication, which not only protects the shaft from wear but also makes the solid lubrication characteristics eternal. The hardness of high force brass is twice as high as the general brass bushing, and the wear resistance is twice as high, and the bearing capacity is high.
Composite Bearings
The common composite bearing is made by combining two layers of the steel plate and copper powder layer (bi-metal bushing), or three layers of steel plate, copper powder layer, and self-lubricating material (PTFE, PEEK, POM) + filling material. It adopts high-temperature sintering process to bond the self-lubricating material on the steel plate, which not only ensures the friction and wear performance of the working surface of the product but also ensures the structural stability and load-bearing capacity of the bearing.
Oilless bushing, Self-lubricating Bearings Bushing
Oil-containing bearings are made of metal materials, and the bearings are oiled and sealed with lubricating oil, so that they can be used without adding oil to achieve the effect of “self-lubrication”. Since the bearing contains oil lubricant, it has good lubrication and avoids oiling and maintenance work.
New Single Lubricant Bearings
New single-lubricated material bearings are common resin, ceramic, tungsten carbide bearings, etc., and new materials are constantly being developed, but these bearings may have high costs, narrow application area, etc., and cannot be widely promoted to replace rolling bearings.
Advantages of self-lubricating bearings bushing
Applicable occasions
Self-lubricating Bearings Bushing Oil-free lubrication or oil less lubrication, suitable for places where it is impossible or difficult to add oil, can be used without maintenance or less maintenance, and also eliminates the risk caused by insufficient oil supply.
No oil supply device required
No oil supply device is required, and oiling can be eliminated during operation, thus saving significant installation and operation costs. Oil-free can make the design and structure, etc. significantly simplified, reducing costs and saving design time.
Green and Environmentally Friendly
No need for waste oil recycling treatment, which is good for environmental protection.
Reduced requirements for grinding parts
The hardness requirement for grinding shafts is low, and shafts without tempering treatment can be used, thus reducing the difficulty of machining related parts.
High and low-temperature resistance
Resistant to high and low temperatures, some products are suitable for temperatures from -200°C to 600°C.
Self-lubricating bearing bushing applications
Engineering and construction machinery
Crank arm bushings, guide wheel bushings, oil cylinders, gear oil pumps, driven wheels, driven wheels, rotary tables, grapple joints and other parts in excavators, bulldozers, scrapers, rotary drilling rigs, lifting machines, handlers, forklifts, and other machinery.
Plastic and rubber machinery
Injection molding machine, tire curing machine, blowing machine, molding machine and other machinery such as crosshead, locking mold, oil cylinder, machine hinge, operating mechanism and other parts.
Automobile parts
Transmission, differential, clutch, balance axle, connecting rod bushings, throttle body, tension wheel, turbocharger, injection pump, idler pulley, oil pump, rocker arm bushings, shock absorber, steering machine, steering resistance pump, hinge, wiper, and other parts.
Office equipment fitness equipment
Copiers, printers, fitness equipment, sewing machines and other machinery requiring transmission or reciprocating motion parts.
Mold guide bush
Parts of the mold such as guide, diagonal fit, positioning, guide rail, etc.
Food and pharmaceutical machinery
Because of the high requirements for the production environment, the rotating and reciprocating parts of food machinery and pharmaceutical machinery
Failure mode
Abrasive particle wear
Some of the hard particles that enter the bearing gap rotate with the shaft and act as abrasive to the bearing surface.
Scratching
The hard particles entering the bearing gap or the rough microscopic contour spikes on the surface of the shaft diameter scratch the bearing surface with linear scars.
Gluing
When the transient temperature rise is too high, the load is too large, and when the oil film rupture or insufficient oil supply, bearing surface material adhesion and migration occurs, causing bearing damage.
Fatigue spalling
Under the repeated action of the load, the bearing surface fatigue cracks perpendicular to the sliding direction, after the expansion of the bearing material spalling
Corrosion
Lubricants in use constantly oxidation, the acid generated on the bearing material has corrosion, material corrosion is easy to form pitting spalling. There is also cavitation fluid erosion electric erosion.
Self-lubricating bearing characteristics description
Oil-free lubrication or oil-less lubrication is suitable for places where oiling is not possible or difficult and to avoid mixing of lubricating oil as well as no or less maintenance during use and also eliminates the risk caused by insufficient oil supply. No oiling device is required, no oiling device is required, no oiling is required during operation, and therefore significant installation and operating costs can be saved. Oil-free can make the design and structure greatly simplified, reducing costs and saving design time Green, no need for waste oil, recycling, and environmental protection. Reduced requirements for grinding parts, low hardness requirements for grinding shafts, untempered shafts can be used, thus reducing the difficulty of processing related parts. High and low temperature resistance, high and low temperature resistance; some products are applicable temperature -200℃ to 600℃.

Application of oil-free Self-lubricating Bearings Bushing: construction machinery; excavators, bulldozers, scrapers, rotary drilling rigs, lifting machinery, conveyors, forklifts, etc. Machinery crank arm bushings, guide wheel bushings, oil cylinders, gear oil pumps, driven wheels, driven wheels, rotary tables, grapple joints and other parts. Plastic and rubber machinery: injection molding machine; tire vulcanizing machine; blowing machine; forming machine and other machinery of crosshead locking, oil cylinder? Machine hinge? Operating mechanism and other parts. Auto parts shifter, differential, clutch, balance axle linkage bushing, throttle body, tensioner wheel, turbocharger, injection pump, idler wheel, oil pump, rocker arm bushing? Shock absorber, steering machine, steering resistance pump? Hinges, wipers and other parts. Office equipment fitness equipment: copiers, printers, fitness equipment, sewing machines and other machinery that requires transmission or reciprocating motion parts. Mold guide bush Mold guide, diagonal fit, positioning, guide rail and other parts of the food and pharmaceutical machinery. Because of the high requirements of the production environment: food machinery; pharmaceutical machinery rotation and reciprocating motion parts of the oil-free lubrication bearing failure mode Abrasive wear The hard particles that enter the bearing gap some rotate with the shaft? Abrasive effect on the bearing surface. Scratching The hard particles entering the bearing gap or the rough surface of the shaft diameter microscopic profile spikes, scratching a linear scar on the bearing surface. Gluing when the instantaneous temperature rise is too high load is too large oil film rupture or insufficient oil supply bearing surface material adhesion and migration caused by bearing damage. Fatigue spalling in the load has to be repeatedly under the action of the bearing surface with the sliding direction of the fatigue crack expansion caused by bearing material spalling corrosion lubricant in use constantly oxidation generated by the acidic material on the bearing material has corrosion material corrosion prone to the formation of point-like spalling.

Sliding friction occurs when the sliding bearing works; the size of the sliding friction mainly depends on the manufacturing accuracy; and the size of the sliding bearing friction mainly depends on the material of the sliding surface of the bearing.