Asia United Machinery CO.,LTD

Ceramic bearing

2018-09-13 16:15:39

1. Advantages:

First, since ceramics are hardly corrosive, ceramic rolling bearings are suitable for operation under harsh conditions filled with corrosive media.

Second, since the density of the ceramic rolling ball is lower than that of the steel, the weight is much lighter, so the centrifugal effect of the outer ring can be reduced by 40% when rotating, and the service life is greatly extended.

Third, ceramics are less affected by thermal expansion and contraction than steel. Therefore, when the clearance of the bearing is constant, the bearing can be allowed to work in an environment where the temperature difference changes drastically.

Fourth, since the modulus of elasticity of ceramics is higher than that of steel, it is not easily deformed when subjected to force, so it is advantageous to increase the working speed and achieve higher precision.

2. Main uses:

Ceramic bearings have high temperature resistance, cold resistance, wear resistance, corrosion resistance, resistance to magnetic and electrical insulation, oil-free self-lubrication, high speed and other characteristics. It can be used in extremely harsh environments and special working conditions. It can be widely used in aviation, aerospace, marine, petroleum, chemical, automotive, electronic equipment, metallurgy, electric power, textile, pump, medical equipment, scientific research and national defense military. High-tech products for new materials applications.

The ferrule and rolling element of the ceramic bearing are made of all ceramic materials, including zirconia (ZrO2), silicon nitride (Si3N4), and silicon carbide (Sic). The retainer is made of polytetrafluoroethylene, nylon 66, polyetherimide, zirconia, silicon nitride, stainless steel or special aviation aluminum to expand the application of ceramic bearings.

3. Application areas:

Medical equipment, cryogenic engineering, optical instruments, high-speed machine tools, high-speed motors, printing machinery, food processing machinery.

In the fields of aerospace, marine, nuclear, petroleum, chemical, textile, machinery, metallurgy, electric power, food, locomotive, subway, high-speed machine tools and scientific research, national defense, military technology, high temperature, high speed, deep cold, flammable, Explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction and other special working conditions, the indispensable replacement of ceramic bearings is gradually being recognized.

With the continuous advancement of processing technology and the increasing level of technology, the cost of ceramic bearings has been declining. From the past, it has only been applied in a small range of high, fine and pointed fields, and gradually extended to various industrial fields of the national economy. It is also gradually approaching practical use, reaching the level acceptable to users, and the wave of large-area application of ceramic bearings has already arrived!

4. Use classification:

(1) High-speed bearing: It has the advantages of cold resistance, small elasticity, high pressure resistance, poor thermal conductivity, light weight, small friction coefficient, etc. It can be applied to high speed spindles of 12000 rpm/-75000 rpm and others. High precision equipment;

(2), high temperature bearing: the material itself has a high temperature resistance of 1200 ° C, and self-lubricating, the use temperature does not produce expansion due to temperature difference between 100 ° C and 800 ° C. Can be used in high temperature equipment such as furnace, plastic, steel, etc.;

(3) Corrosion-resistant bearings: The materials themselves have corrosion-resistant properties and can be applied in fields such as strong acids, alkalis, inorganics, organic salts, seawater, etc., such as electroplating equipment, electronic equipment, chemical machinery, shipbuilding, medical equipment, etc. .

(4) Anti-magnetic bearing: Because it is non-magnetic and does not absorb dust, it can reduce the early peeling of the bearing and the noise. Can be used in demagnetization equipment. Precision instruments and other fields.

(5), electrically insulated bearings: due to high resistance, can avoid arc damage bearings, can be used in a variety of electrical equipment requiring insulation.

(6), vacuum bearing: due to the unique oil-free self-lubricating properties of ceramic materials, in the ultra-high vacuum environment, it can overcome the problem that ordinary bearings can not achieve lubrication. Note: The above five types of bearings, the same set of bearings can be applied to high temperature, high speed, acid and alkali, magnetic field, non-insulation, but due to different material properties (please refer to the rare earth ceramic material performance table), so when customers choose products, Choose the most suitable ceramic bearing for your application, depending on the application you are using.

5. Material classification:

Zirconium oxide full ceramic bearings are resistant to magnetic and electrical insulation, wear and corrosion resistance, oil-free self-lubricating, high temperature and high temperature resistance, and can be used in extremely harsh environments and special working conditions. The ferrule and rolling element are made of zirconia (ZrO2) ceramic material, and the retainer is made of polytetrafluoroethylene (PTFE) as standard. Generally, glass fiber reinforced nylon 66 (RPA66-25) and special engineering plastic (PEEK, PI), stainless steel (AISISUS316), brass (Cu), etc.

Silicon nitride silicon nitride all-ceramic bearing rings and rolling elements are made of silicon nitride (Si3N4) ceramic materials, and generally RPA66-25, PEEK, PI, and phenolic cloth bakelite tubes can also be used. Compared to ZrO2, the SiN4 all-ceramic bearing is suitable for higher speed and load capacity, as well as for higher ambient temperatures. At the same time, it can provide precision ceramic bearings for high-speed, high-precision and high-rigidity spindles with the highest manufacturing precision up to P4 to UP.

The full-ball full-ball type ceramic bearing has a ball gap on one side. Because of the cage-free design, it can load more ceramic balls than the standard structure bearing, thus improving its load capacity and avoiding the cage. The limitation of materials can achieve the corrosion resistance and temperature resistance of ceramic cage type full ceramic bearings. This series of bearings is not suitable for high speed. When installing, please pay attention to the notch surface to the end that does not bear the axial load.

The mixed ceramic ball, especially the silicon nitride ball, has the characteristics of low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity, and is particularly suitable for rolling elements of high-speed, high-precision and long-life hybrid ceramic ball bearings (inside and outside) The circle is metal). Generally, the inner and outer rings are made of bearing steel (GCr15) or stainless steel (AISI440C), and the ceramic balls are made of ZrO2, Si3N4, or SiC.