advantage
First, because ceramics are almost not afraid of corrosion, ceramic rolling bearings are suitable for operating under harsh conditions full of corrosive media.
Second, because the density of the ceramic rolling ball is lower than that of steel, the weight is much lighter, so the centrifugal effect on the outer ring can be reduced by 40% during rotation, and the service life is greatly extended.
Third, ceramics are less affected by thermal expansion and contraction than steel, so when the clearance of the bearing is constant, the bearing can be allowed to work in an environment with severe temperature changes.
Fourth, since the modulus of elasticity of ceramics is higher than that of steel, it is not easy to deform when stressed, so it is beneficial to improve the working speed and achieve higher precision.
The main purpose of ceramic bearings
Ceramic bearings have the characteristics of high temperature resistance, cold resistance, wear resistance, corrosion resistance, anti-magnetic and electrical insulation, oil-free self-lubrication, high speed and so on. It can be used in extremely harsh environments and special working conditions, and can be widely used in aviation, aerospace, navigation, petroleum, chemical industry, automobiles, electronic equipment, metallurgy, electric power, textiles, pumps, medical equipment, scientific research and national defense military and other fields. High-tech products with new material application.
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 cage is made of polytetrafluoroethylene, nylon 66, polyetherimide, zirconia, silicon nitride, stainless steel or special aviation aluminum, so as to expand the application surface of ceramic bearings.
Application field of ceramic bearing
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, light textile industry, machinery, metallurgy, electric power, food, locomotive, subway, high-speed machine tools and scientific research, national defense and military technology, etc. Working under special conditions such as explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction, etc., ceramic bearings are gradually being recognized as an indispensable substitute.
With the continuous improvement of processing technology and the increasing level of technology, the cost of ceramic bearings has been continuously decreasing. It has been used in a small range of high-end, precision and cutting-edge fields in the past, and has been gradually extended to various industrial fields of the national economy. The market price of products It is also gradually approaching practicality and reaching the level acceptable to users. The wave of large-area application of ceramic bearings has come!
Classification of ceramic bearings
(1) High-speed bearings: have the advantages of cold resistance, small elastic force, high pressure resistance, poor thermal conductivity, light weight, small friction coefficient, etc., and can be applied to high-speed spindles of 12000 rpm- 75000 rpm and others In high-precision equipment;
(2) High temperature resistant bearing: The material itself has a high temperature resistance of 1200°C, and is self-lubricating well, and the operating temperature does not cause expansion due to temperature difference between 100°C and 800°C. can be used in high temperature equipment such as kiln, plastic making and steel making;
(3) Corrosion-resistant bearings: The material itself has the characteristics of corrosion resistance, and can be used in strong acid, strong alkali, inorganic, organic salt, seawater and other fields, such as: electroplating equipment, electronic equipment, chemical machinery , shipbuilding, medical equipment, etc. .
(4) Anti-magnetic bearing: Because it is non-magnetic, it does not absorb dust, which can reduce the peeling of the bearing surface, thereby reducing the running noise. Can be used in demagnetization equipment. Precision instruments and other fields.
(5) Electrically insulated bearings: Due to the high resistance, arc damage to the bearings can be avoided, and they can be used in various electrical equipment requiring insulation.
(6) Vacuum bearings: due to the unique oil-free self-lubricating properties of ceramic materials, in an ultra-high vacuum environment, it can overcome the difficulty that ordinary bearings cannot achieve lubrication. Note: For the above five types of bearings, the same set of bearings can be applied to high temperature, high speed, acid and alkali, magnetic field, and non-insulation, but due to the different material properties (please refer to the performance table of rare earth ceramic materials), customers should choose products. Choose the ceramic bearing with the most suitable material according to your application.
Classification of ceramic bearing materials
1. Ceramic bearing zirconia
All-ceramic bearings have the characteristics of anti-magnetic and electric insulation, wear and corrosion resistance, oil-free self-lubrication, high temperature and cold resistance, etc., and can be used in extremely harsh environments and special working conditions. Rings and rolling elements are made of zirconia (ZrO2) ceramic material, and polytetrafluoroethylene (PTFE) is used as a standard configuration for cages. Generally, glass fiber reinforced nylon 66 (RPA66-25), special industrial plastics (PEEK, PI), stainless steel (AISISUS316), flavonoids (Cu), etc.
2. Ceramic bearing silicon nitride
Silicon nitride full-ceramic bearing rings and rolling elements are made of silicon nitride (Si3N4) ceramic materials. Generally, RPA66-25, PEEK, PI, and phenolic laminated bakelite tubes can also be used. Compared with ZrO2 material, SiN4 all-ceramic bearings are suitable for higher speed and load capacity, as well as higher ambient temperature. At the same time, precision ceramic bearings for high-speed, high-precision, and high-rigidity spindles can be provided, and the highest manufacturing accuracy can reach P4 to UP level.
3. Full complement balls of ceramic bearings
The full-complement ball-type all-ceramic bearing has ball gaps on one side. Due to the non-cage structure design, more ceramic balls can be loaded than standard structure bearings, thereby improving its load capacity. In addition, it can also avoid the limitation of the cage material. , It can achieve the effect of corrosion resistance and temperature resistance of ceramic cage type full ceramic bearings. This series of bearings is not suitable for high speed. When installing, pay attention to install the notched surface on the end that does not bear the axial load.
4. Hybrid ceramic bearings
Ceramic balls, especially silicon nitride balls, have the characteristics of low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity, and are especially suitable for rolling elements (inner and outer rings) of high-speed, high-precision and long-life hybrid ceramic ball bearings. for 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.
Classification of ceramic bearings
Ceramic Bearings Deep Groove Ball Bearings
(Technical grades: P4, P5, P6, P0) Deep groove ball bearings, the most representative rolling bearings, are widely used and can bear radial loads and bidirectional axial loads. It is suitable for high-speed rotation and occasions requiring low noise and low vibration, or high temperature, high cold, corrosion, magnetic field, non-insulation and other fields where steel bearings cannot be used.
Ceramic Bearing Self-aligning Ball Bearing
The raceway of the outer ring of the self-aligning ball bearing is spherical and self-aligning, which can compensate for errors caused by misalignment and shaft deflection. It is used to produce non-concentric or shaft deflection parts of the shaft and the shell, and self-aligning parts that require high temperature, low cold, corrosion, and non-insulation of magnetic fields. Note: The inclination cannot exceed 3 degrees.
Ceramic bearing single row angular contact ball bearing
(Technical grades: P4, P5, P6, P0) Angular contact bearings are suitable for high-speed and high-precision rotation, and their precision will not be affected by high temperature, magnetic field, water, etc., and can withstand synthetic loads. The standard contact angles are 15°, 30° and 40°. The larger the contact angle, the greater the axial load capacity, and the smaller the contact angle, the bearing can bear radial load and one-way axial load. Usually installed in pairs. Please pay attention when purchasing.
Ceramic bearing one-way thrust ball bearing
Single-phase thrust ball bearings are composed of a washer-shaped ring with a ball rolling raceway and a cage assembled with balls. Can bear axial load, but not radial load.
