What Is A Porous Bearing
Porous bearing is a kind of bearing with the advantage of self-lubrication, its characteristic is that oil oozes out from the hole in the operation and lubricates on the friction surface, and once the operation stops, the oil is sucked into the hole again, so a small amount of oil can be used for long time lubrication. In addition, it does not glue with heat and is inexpensive, so it is now widely used in audio, home appliances, automotive electrical equipment, etc.
Porous Bearing Material Characteristic
Bronze: The most common porous bearing material. It contains 90% copper and 10% tin. These bearings are wear-resistant, ductile, conformable, and corrosion-resistant. Their lubricity, embeddability, and low cost give them a wide range of applications from home appliances to farm machinery.
Leaded Bronzes: Have a 20% reduction of the tin content of the usual 90-10 bronze and a 4% reduction in copper. Lead content is 14% to 16% of the total composition and results in a lower coefficient of friction and good resistance to galling in case the lubricant supply is interrupted. These alloys also have higher conformability than 90-10 bronzes.
Copper-Iron: The inclusion of iron in the composition boosts compressive strength although the speed limit drops accordingly. These materials are useful in applications involving shock and heavy loads and should be used with hardened shafts.
Hardenable Copper-Iron: The addition of 1-1/2% free carbon to copper-iron materials allows them to be heat treated to a particle hardness of Rockwell C65. They provide high impact resistance and should be used with hardened-and-ground shafts.
Iron: Combine low cost with good bearing qualities, widely used in automotive applications, toys, farm equipment, and machine tools. Powdered iron is frequently blended with up to 10% copper for improved strength. These materials have a relatively low limiting value of PV (on the V side) but have high oil-volume capacity because of high porosity. They have good resistance to wear but should be used with hardened-and-ground steel shafts.
Leaded-Iron: Provide improved speed capability, but are still low-cost bearing materials.
Aluminum: In some applications, they provide cooler operation, greater tolerance for misalignment, lower weight, and longer oil life than porous bronze or iron. The limiting PV value is 50,000, the same as for porous bronze and porous iron.”
Wholesale Porous Bearing | Material
The material of porous bearing is roughly divided into four kinds: copper, paste, copper-iron, and aluminum. The affinity of copper is good, the mechanical strength of iron is high, and copper and iron have a specialty of intermediate nature between the two. Aluminum is light in weight and has good heat transfer.
Most porous-metal bearings consist of either bronze or iron which has interconnecting pores. These voids take up 10% to 35% of the total volume. In operation, lubricating oil is stored in these voids and feeds through the interconnected pores to the bearing surface. Any oil which is forced from the loaded zone of the bearing is reabsorbed by capillary action. Since these bearings can operate for long periods without an additional supply of lubricant, they can be used in inaccessible or inconvenient places where relubrication would be difficult.
wholesale porous bearing
High Performance Porous Bearing
Main features of porous bearings.
Advantages: 1. Adapt to mass production
2. Elimination of cutting process, saving cost
3. Compared with rolling bearings, the sound is smaller
4. Self-lubricating effect, no heat gluing
5. No need or only need a small amount of oil supply
Disadvantages: 1. Not suitable for multi-species small batch production
2. Mechanical strength (compressive strength) is weak because of hollow holes inside the bearing
3 load capacity is small, most of the mixed lubrication or critical lubrication state, and therefore compared with the sliding bearing, the coefficient of friction is relatively large
Many Variations Are Possible To Meet Specific Requirements.
From 1% to 3.5% graphite is frequently added to enhance self-lubricating properties. High porosity with a maximum amount of lubricating oil is used for high-speed light-load applications, such as fractional-horsepower motor bearings. A low-oil-content low-porosity material with a high graphite content is more satisfactory for oscillating and reciprocating motions where it is hard to build up an oil film.
Porous Metal Bearing | Lubricating
The lubrication characteristics of porous oil-impregnated bearings are related to load capacity, friction coefficient, bearing temperature, etc. Its lubrication method is that the oil flows into the bearing from the bearing gap, flows and lubricates in the bearing, and at the same time flows into the bearing gap again. Porous oil-impregnated bearings can be lubricated in a wide range of forms, including from fluid lubrication to mixed or critical lubrication, as well as factors related to lubricating characteristics (such as the oil content inside the bearing, the permeability of the porous body, the porosity, the friction surface The material combination, the physical and chemical properties of the oil used for penetration, etc.) are more complicated than conventional plain bearings.
wholesale porous bearing
Economical & Practical Sinter Bushing
Porous-metal bearings are used widely in instruments and general machinery, in which their self-lubricating characteristics and load-carrying ability are very desirable. When properly designed, they can be both economical and highly functional. Their manufacturing method consists of briquetting the metal powder mixtures to the proper density. Subsequently, they are sintered for different duration subject to the temperatures. Sintered bearings are then sized to obtain the required dimensional characteristics. This is followed by inspection and impregnation with lubricating oil.