Bearings for alloys, bronze, aluminum-based alloys, zinc-based alloys, etc. are known as metal structural materials. Among them, bearing as well as alloy technology is also called a white alloy, mainly lead, tin, antimony, or some other metal alloy, it can be under heavy load, high speed, etc., and the strength impact is small. The reason is mainly because of its characteristics, good wear resistance type, high plasticity, good running together performance, good thermal conductivity, and good anti-gumming, and good adsorption with oil. However, because it is more expensive, it must be poured on bronze, steel strips, or cast iron shingles at the same time to form a thinner coating when it is used.
Bearing alloy is an alloy composed of tin, lead, antimony and copper, based on tin or lead, containing sb-sn and cu-sn hard grains. The hard grains have an anti-wear effect and the soft base material has the effect of increasing the plasticity of the material. Bearing alloys have low modulus of elasticity and elastic limit, and among all bearing materials, their embeddedness and friction flexibility are the best, easy to wear with the journal and not easy to bite and adhere to the journal. However, the strength of bearing alloys is very low, and they cannot be made into shingles alone. They can be attached to bronze, steel or cast iron shingles for lining. Bearing alloys are suitable for heavy-duty, high-speed operation and are more expensive.
Copper alloy as has relatively high strength, better friction reduction, and wear resistance. Bronze has better performance than ordinary brass and is the most commonly used material. Bronze has several kinds of tin bronze, lead bronze, aluminum bronze, etc., of which tin bronze has the best friction reduction and a wide range of applications. But tin bronze than the bearing for alloy surface hardness, abrasion, and embeddedness is poor, suitable for our heavy load and medium speed operation occasions. Lead bronze anti-adhesive technology ability is strong and suitable for China’s high-speed, heavy-duty equipment bearings. Aluminum bronze strength and hardness requirements are high, anti-adhesion problem ability development is poor, suitable for economic low speed, heavy load as well as bearings.
Aluminum-based bearing alloys have fairly good corrosion resistance and high fatigue working strength, and the friction material performance is also better. These product qualities make aluminum-based alloys in part of the development of research areas to replace the more expensive bearing alloys and Chinese bronze. Aluminum-based alloy company can be made into a single target metal processing parts (such as bushings, bearings, etc.), can also be made into nano-bimetallic due to parts, bimetallic shaft tiles to aluminum-based alloy for the bearing liner, steel for the backing.
Ordinary gray cast iron or wear-resistant gray cast iron containing nickel, chromium, titanium and other alloys, or ductile iron, can be used as bearing materials. The flake or spherical graphite in this material can form a lubricated graphite layer after covering the surface of the material, which has certain wear-resistant and friction-reducing properties. In addition, graphite can also adsorb hydrocarbons, which helps to improve the boundary lubrication performance. Therefore, when using gray cast iron as bearing material, lubricating oil should be added. Cast iron is only suitable for light load, low speed and no impact load due to its brittleness and poor wear.
The main application of non-metallic materials studied the most is a variety of different plastics (polymer composites), such as phenolic resins, nylon, polytetrafluoroethylene, etc.. Polymer characteristics are: with many students chemical analysis substances do not react, anti-corrosion ability to carry out particularly strong; has China a certain self-lubricating, can work in the enterprise without lubrication conditions, in high temperature environmental conditions development has the existence of a certain lubrication management ability; embedded good; friction reduction and wear resistance are relatively good.
Porous Metallic Materials
This is a bearing material that is pressed and sintered using different metal powders. This material is porous in structure with a porosity of about 10% ~ 35% of the volume. Bearings made of this material are often called oil bearings because they are soaked in hot oil for several hours before use to fill the pores with lubricant.
Oil Impregnation bronze bushing is self-lubricating.
When working, due to the role of different journals rotating suction system and the effect of oil expansion when the bearing is hot, the oil will enter the economic friction material surface between the lubrication management role; when not working, because of the capillary effect, the oil will be sucked back to the bearing inside, so in a long time, even if we do not add lubricant can still get a good job. If we can supply oil regularly, the effect will be better. However, because of its relatively small toughness, it is suitable for the development of smooth and shock-free as well as load and low to medium growth rate change situations. Commonly used are porous iron and porous quality bronze. Porous iron is commonly used to design and make mill bushings, machine tool oil pump bushings, internal combustion engine camshaft bushings, etc.
Precautions For Bearing Use
Selection and control of shaft and bearing chamber tolerances
The bearing should rotate flexibly without blocking the feeling after pressing into the bearing. If there is obvious rotation inflexibility, it indicates that the size of the shaft is too large and the tolerance should be adjusted downward. If there is an obvious “rustling” feeling after the bearing is pressed into the shaft, the tolerance of the shaft may be too large or the roundness of the shaft is not good. So the control of the shaft and bearing room tolerances should also control the roundness. The bearing is not only good but also a good bearing.
Bearing assembly method.
Because the bearing chamber is a high-precision product, improper assembly can easily cause damage to the bearing groove and lead to bearing damage. Bearings in the assembly should have a special mold, and not be randomly knocked.
Prevention of foreign objects in an assembly
Bearings in the installation to the rotor to do dynamic balancing is easy to dynamic balancing when the iron particles are generated into the bearing inside, so it is best to do dynamic balancing before installing bearings