Ceramic Bearings, as an indispensable transmission component in the industrial system, are designed with different materials according to different application requirements. Chrome steel bearings are the most common type. Stainless steel bearings and ceramic bearings are relatively high-cost materials. The requirements of equipment for corrosion resistance, high temperature, dust resistance, High speed, etc. have been improved, and it has become more and more widely used in the market.
The performance comparison of ordinary bearing steel AISI52100 (GCr15), stainless steel AISI440 (9Cr18), silicon nitride (Si3N4) and zirconia (ZrO2) four kinds of bearing materials, ceramic bearing as an important mechanical basic part, because of its metal bearing Unmatched excellent performance, high temperature resistance, super strength, etc. take the lead in the world of new materials. In the past ten years, it has been widely used in various fields of national economy and people’s livelihood.
What Are Full Ceramic Bearings?
Full Ceramic Bearings are often the answer for extreme environments, such as high temperatures, corrosive chemicals, steam, and hard vacuum. These bearings have both the inner and outer rings in addition to the rolling elements manufactured from ceramic material. Like the balls in hybrid bearings, the rings in full ceramic bearings are typically manufactured from silicon nitride, Si3N4, or zirconia, ZrO2. Retainers in full ceramic bearings are typically made from high-performance plastics such as PEEK or PTFE. Full complement versions are also available.
| Characteristics | Unit | Chrome Steel | Stainless Steel | Nitrogen Enhanced Stainless Steel | Si3N4 | ZrO2 |
| Density | g/cm3 | 7,85 | 7,85 | 7,85 | 3,2 | 6,0 |
| Hardness | Rc | >60 | >58 | >60 | >75 | >75 |
| E-Modulus |
| 210 | 200 | 218 | 320 | 200 |
| Poissons Coefficient |
| 0,28 | 0,28 | 0,3 | 0,26 | 0,3 |
| Expansion Coefficient | x 10-6°C | 10,9 | 10,1 | 10,1 | 2,9 | 10 |
| Top Temperature Limit | °C | 170 | 260 | 500 | 1000 | 600 |
| Corrosion Resistance |
| limited | good | very good | very good | good |
| Electrical Conductivity |
| conductor | conductor | conductor | isolator | isolator |
| Magnetism |
| magnetic | magnetic | magnetic | not magnetic | not magnetic |
Advantage of Ceramic Bearings
1. ceramics are almost not afraid of corrosion, ceramic rolling bearings are suitable for operation under harsh conditions full of corrosive situation.
2. Because the density of the ceramic rolling ball is lower than that of 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.
3. Ceramics are less affected by thermal expansion and contraction than steel, so when the bearing gap is constant, the bearing can be allowed to work in an environment where the temperature difference changes more drastically
4. Since the elastic modulus of ceramic is higher than that of steel, it is not easy to deform when subjected to force, so it is beneficial to increase the working speed and achieve higher accuracy
The main purpose
Ceramic bearings have the characteristics of high temperature resistance, cold resistance, wear resistance, corrosion resistance, anti-magnetic and electrical insulation, oil-free self-lubricating, and high speed. It can be used in extremely harsh environments and special working conditions. It can be widely used in aviation, aerospace, navigation, petroleum, chemical, automotive, electronic equipment, metallurgy, electric power, textiles, pumps, medical equipment, scientific research, national defense and military fields. High-tech products for the application of new materials.
Ceramic bearings have the characteristics of high temperature resistance, cold resistance, wear resistance, corrosion resistance, anti-magnetic and electrical insulation, oil-free self-lubricating, and high speed. It can be used in extremely harsh environments and special working conditions. It can be widely used in aviation, aerospace, navigation, petroleum, chemical, automotive, electronic equipment, metallurgy, electric power, textiles, pumps, medical equipment, scientific research, national defense and military fields. High-tech products for the application of new materials.
The rings and rolling elements of ceramic bearings are made of all-ceramic materials, including zirconia (ZrO2), silicon nitride (Si3N4), and silicon carbide (Sic). The retainer is made of PTFE, nylon 66, polyetherimide, zirconia, silicon nitride, stainless steel or special aviation aluminum, thereby expanding the application range of ceramic bearings.
Application field
Medical equipment, cryogenic engineering, optical instruments, high-speed machine tools, high-speed motors, printing machinery, food processing machinery.
In the fields of aerospace, navigation, nuclear industry, petroleum, chemical industry, textile industry, machinery, metallurgy, electric power, food, locomotives, subways, high-speed machine tools, scientific research and defense military technology, it is necessary to use high temperature, high speed, cryogenic, flammable, Working under special working conditions such as explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction, etc., the indispensable substitute role of ceramic bearings is gradually being recognized by people.
With the continuous progress of processing technology and the increasing level of craftsmanship, the cost of ceramic bearings has been declining. From the past, it has only been applied in a small range of high, precise and cutting-edge fields, and has been gradually extended to various industrial fields of the national economy. The product market price It is also gradually approaching practicality, reaching a level acceptable to users. The wave of large-scale application of ceramic bearings has surged.
Classification of ceramic bearings
1. High-speed bearing: It has the advantages of cold resistance, small force elasticity, high pressure resistance, poor thermal conductivity, light weight, and low friction coefficient. It can be used in high-speed spindles and other high-precision equipment at 12,000 rpm to 75,000 rpm
2. High temperature resistant bearing: The material itself is resistant to high temperature of 1200°C, and it is self-lubricating. The use temperature is between 100°C and 800°C without expansion caused by temperature difference. Can be used in high temperature equipment such as furnaces, plastics, steel, etc.
3. Corrosion-resistant bearings: The material itself has corrosion-resistant properties and can be used in fields such as strong acids, strong alkalis, inorganic, organic salts, and seawater, such as: electroplating equipment, electronic equipment, chemical machinery, shipbuilding, medical equipment, etc.
4. Antimagnetic bearing: Because it is non-magnetic, it does not absorb dust, which can reduce the peeling of the bearing surface, thereby reducing the operating noise. Can be used in demagnetization equipment. Precision instruments and other fields.
5. Electrically insulated bearings: Because of their high resistivity, they can avoid arc damage to the bearings and can be used in various electrical equipment requiring insulation.
6. Vacuum bearings: Due to the unique oil-free and self-lubricating properties of ceramic materials, it can overcome the problem that ordinary bearings cannot achieve lubrication in an ultra-high vacuum environment. Note: For the above five types of bearings, the same set of bearings can be applied to high temperature, high speed, acid-base, magnetic field, and non-insulation. However, due to the different material properties, please choose the product according to your application. Select the ceramic bearing with the most suitable material
Zirconia ceramic bearing
All-ceramic bearings have the characteristics of anti-magnetic and electrical insulation, wear-resistance and corrosion resistance, oil-free self-lubrication, high temperature resistance and high cold resistance, and can be used in extremely harsh environments and special working conditions. The ferrule and rolling elements are made of zirconia (ZrO2) ceramic material, and the retainer uses polytetrafluoroethylene (PTFE) as the standard configuration. Generally, glass fiber reinforced nylon 66 (RPA66-25), special engineering plastics (PEEK, PI), stainless steel (AISISUS316), brass (Cu), etc.
Silicon nitride ceramic bearing
Silicon nitride full ceramic bearing rings and rolling elements are made of silicon nitride (Si3N4) ceramic materials. Generally, RPA66-25, PEEK, PI, and phenolic cloth bakelite pipes can also be used. Compared with ZrO2 material, SiN4 full ceramic bearings can be applied to higher speed and load capacity, as well as higher ambient temperature. At the same time, it can provide precision ceramic bearings for high-speed, high-precision and high-rigidity spindles, with the highest manufacturing accuracy reaching P4 to UP.
Full complement full ceramic bearing
The full complement full ceramic bearing has a ball-filling gap on one side. Due to the cageless structure design, more ceramic balls can be loaded than the standard structure bearing, thereby improving its load capacity and avoiding the limitation of the cage material. , Can achieve the corrosion resistance and temperature resistance of ceramic cage type full ceramic bearings. This series of bearings are not suitable for higher speeds. When installing, pay attention to installing the notched surface on the end that does not bear the axial load.
Ceramic balls, especially silicon nitride balls, have the characteristics of low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity. They are especially suitable for high-speed, high-precision and long-life hybrid ceramic ball bearings. Is metal). Generally, the inner and outer rings are made of bearing steel (GCr15) or stainless steel (AISI440C), and the ceramic balls can be made of ZrO2, Si3N4, or SiC.
Design of the rolling elements
Deep groove ball bearing
(technical grade: P4, P5, P6, P0) Deep groove ball bearing, the most representative rolling bearing, has a wide range of applications, and can withstand radial load and bidirectional axial load. It is suitable for high-speed rotation, low noise, low vibration, high temperature, cold, corrosion, magnetic field, non insulation, etc.
self-aligning ball bearing
The outer ring raceway of the self-aligning ball bearing is spherical, which can be self-aligning to supplement the errors caused by different centrality and shaft deflection. It is used to produce the non concentricity between the shaft and the shell or the shaft bending parts, as well as the alignment parts required by high temperature, low cold, corrosion, magnetic field non insulation, etc. Note: the inclination should not exceed 3 degrees.
Single row angular contact ball bearing
(technical grade: P0, P6, P5, P4, P2) Angular contact bearings are suitable for high-speed and high-precision rotation, in high temperature, magnetic field, water does not affect its accuracy, and can withstand synthetic load. The standard contact angle is 15 degree, thirty degree And 40 degree, The larger the contact angle is, the larger the axial load capacity is, and the smaller the contact angle is, the bearing can bear radial load and unidirectional axial load. Generally, it is installed in pairs. Please pay attention when purchasing.
One way thrust ball bearing
One way thrust ball bearing is composed of washer ring with ball rolling raceway and cage with ball assembled. It can bear axial load, but not radial load.
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