RAH Ceramic Ball Bearings Manfaucturer

Name	Ceramic ball bearings	Advatange	high degree of standardisation
Application	development and application of engineering ceramic products	SS	stainless steel
The other name	rolling body using hot pressed Si3N4 ceramic balls	S	indicates stainless steel

In the development and application of engineering ceramic products, ceramic ball bearing is a typical example of the wide application of engineering ceramics in the industrial field, which is highly valued by many countries. In the high-speed precision bearings, the most widely used is the hybrid ceramic ball bearings, that is, the rolling body using hot-pressed Si3N4 ceramic balls, the bearing ring is still a steel ring. This kind of bearing has a high degree of standardisation, small changes to the structure of the machine tool, easy to maintain, especially suitable for high-speed running occasions. Its assembly of high-speed spindle, with high speed, high stiffness, high power, long life and other advantages.1.Bearing configuration: inner and outer ring bearing steel/stainless steel + ceramic ball + PA66/stainless steel keeper +2RS/ZZ2.High temperature grease, 3.The advantages of using ceramic ball bearings compared with ordinary bearings.

vantage
High temperature resistance
Ceramic ball thermal expansion coefficient is small, in the high temperature environment will not be caused by the temperature of the bearing ball expansion, which greatly improves the use of the whole bearing temperature, the temperature of ordinary bearings in the 160 degrees or so, ceramic ball can reach 220 degrees or more.

Ceramic ball has oil-free self-lubricating properties, ceramic ball friction coefficient is small, so ceramic ball bearings have a very high speed. According to the statistics, the bearing with ceramic ball is more than 1.5 times of the general bearing speed.

Long life
Ceramic ball can not add any grease, that is to say, even if the grease is dry, the bearings can still operate, which avoids the phenomenon of premature damage caused by the drying out of grease in ordinary bearings. According to our test and some customers' feedback, the service life of the bearings after using ceramic ball is 2-3 times of the normal bearings.

Insulation
The last point is also the most important point, insulation, the use of ceramic ball bearings, can make the bearings of the inner and outer rings of the insulation, because the ceramic ball is an insulator, in the bearings of the inner and outer rings of the ceramic ball, between the insulating effect can be achieved. This makes the bearings can be used in the conductive environment. A rolling bearing consists of a collar, a rolling body, a cage, a grease, and a seal. When the rolling body is made of ceramic material, this rolling bearing is defined as a ceramic ball bearing.

make up
Because the ceramic ball itself has self-lubricating properties, so the lubrication can be used according to the requirements, there can be lubricated Grease can also not add grease. Seals can also be used according to the requirements of the decision ceramic ball bearings with seals or not. Keeper can also be used according to the requirements of whether to use. Then the collar, rolling body is bearing two indispensable elements, when these two elements are not the same material, there is a mixed bearing (Hybrid construction bearing) said. When the rolling body is made of ceramic material, it is defined as hybrid ceramic ball bearing (Hybrid construction ceramic ball bearing). Commonly used ceramic ball materials are zirconium oxide (ZRO2) and silicon nitride (SI3N4); commonly used ring materials are bearing steel (GCR15) and stainless steel (440, 440C) and stainless steel (304, 316, 316L).

According to the use of the environment, speed, load, temperature, and the use of the requirements, ceramic ball bearing rings and rolling body can be combined with each other by the above materials, and play a different use of the effect.

Ceramic ball bearing code.

HY + collar material + bearing type + seal type -- ball material -- keeper material -- grease

RING MATERIAL: S means stainless steel SS means stainless steel What material can be marked with a registered number?

specificities
Practice has proved that as bearing materials must also have the dimensional stability at different temperatures to ensure that bearings in the temperature changes in the working environment, to maintain precision dimensions and accurate fit, in special environments must also have corrosion resistance, resistance to decomposition. In short, used to manufacture rolling shaft
Bearing parts of ceramic materials should have the following performance characteristics: 1) low density. As the rolling body density is reduced, high-speed operation of its centrifugal load is also reduced, thus can work at higher speeds. 2) Medium modulus of elasticity. Too large a modulus of elasticity reduces the load carrying capacity of the bushing due to stress concentration. 3) Small coefficient of thermal expansion. Reduce the sensitivity to temperature changes, so that the bearing working temperature range is wider. 4) High compressive strength. High compressive strength is a rolling bearing to withstand high stress needs. 5) High hardness and high toughness. The combination of these two characteristics can obtain a good surface roughness; and can prevent external particles and impact damage. 6) good rolling contact fatigue resistance and has a spalling failure mode. 7) Special occasions should have high temperature resistance, corrosion resistance and stability.

Rings and rolling body contact point by the role of the applied load and rotation, and thus repeatedly produce contact pressure and deformation. Due to the steel bearing's own material performance characteristics, bearing failure is the main form of fatigue spalling, fatigue life is short, the scope of application is greatly restricted. The ceramic material has the advantages of low density, medium modulus of elasticity, small coefficient of thermal expansion, high hardness, high temperature resistance, corrosion resistance, non-magnetic and so on, with silicon nitride ceramic ball rolling body of ceramic ball bearings can significantly improve the bearing contact fatigue life, greatly expanding the application field of rolling bearing, has been widely used in a variety of high-precision, high speed machine tools, automobiles, racing cars, underground, electric motors, aviation engines, petrochemical machinery, metallurgical machinery and other fields. machinery, metallurgical machinery and other fields.

Silicon Nitride Ceramics
Ceramic bearings are being used in a wide range of applications, but it is the ceramic ball bearings that have been successfully used in industry. Silicon nitride ceramic ball bearings are the most widely used. Its advantages are: high limiting speed, good accuracy retention, small starting torque, High stiffness, good dry running, long life, very suitable for high speed, high temperature and corrosion, radiation conditions to maintain high precision, long operation, mainly used in CNC machine tools and high-speed precision machinery, such as high-speed spindle bearings, machine tool spindle bearings, dental drill bearings, instrumentation bearings, computer hard drive bearings and so on. In addition, the hardness of silicon nitride ceramics is 1 times higher than bearing steel, the modulus of elasticity is about 1/3 higher, under the same load conditions, the elastic deformation of silicon nitride ceramics is small, so the use of ceramic ball bearings for machine tool spindles have good running accuracy.

Hybrid ceramic bearings have been successfully applied to high-speed machine tool spindles, and has entered the practical stage, such as Japan's Makino and other companies to produce the HPM-type ultra-precision lathe, spindle speed of 16 000 r/min, and the United States MIKRO production of HSM700 high-speed machining centres, the spindle speed of 42 000 r/min, the cutting speed increased by 5 to 10 times. In addition, hybrid ceramic bearings should also be used in electric spindles, vortex molecular pumps and other high speed equipment.

Ceramic bearings as an important mechanical infrastructure, because it has metal bearings can not be compared to the excellent performance, high temperature resistance, super strength, etc. in the new materials world leading the way. Over the past decade, in the national economy and people's livelihood in various fields has been increasingly widely used. Aerospace, navigation, nuclear industry, petroleum, chemical industry, textile industry, machinery, metallurgy, electric power, food, locomotives, underground, high-speed machine tools and scientific research in the field of national defence and military technology and other areas need to work in high temperature, high speed, deep cold, flammable, explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction and other special conditions, the product market price is also gradually approaching the practicality of the degree of acceptance by the user, the ceramic The wave of large-scale application of ceramic bearings has come.

Since the 1960s, with the development and application of ceramic materials, ceramic bearings can also be developed. The United States Norton has silicon nitride ceramic bearings used in the space shuttle hydraulic pumps, bearing operating speed increased by 50% to 100%, a U.S. company to the U.S. aerospace industry supply of ceramic bearings have been used in the high temperature of 800 * (2); Japan's main aircraft engine manufacturer Ishikawajima broadcast also steel a ceramic hybrid bearings and all ceramic bearings in the engine for testing.

1. low density: due to the low density of ceramic rolling element material, centrifugal load is small, so that it can work at higher speeds, and generate less heat.

2. Medium modulus of elasticity: The modulus of elasticity of ceramic rolling elements is higher than that of steel rolling elements, which increases the dynamic stiffness of the bearing, but the modulus of elasticity is too large to reduce the bearing capacity due to stress concentration.

3. Small coefficient of thermal expansion: A small coefficient of thermal expansion helps to reduce the sensitivity to temperature changes, thus preventing seizing. For hybrid roller bearings, a wider range of operating speeds can be applied.

4. High compressive strength: High compressive strength is required for rolling bearings to withstand high contact stresses (in the case of ceramic materials, the strength is usually determined by the modulus of rupture measured by a three- or four-point bending test).

5. high hardness and high toughness: the combination of these two properties results in a good surface roughness and protection against external hard particles and impact damage.

6. good resistance to rolling contact fatigue characteristics: this performance is critical to the requirements of the rolling element of the bearing.

7. Forms of spalling failure: If a rolling element fails in operation, it should be fatigue spalling, which is the least harmful form of failure, as it is predicted before seizing. In some applications with high conditions of application ceramic materials also have some special properties. 8.

8. High temperature resistance and stability: in up to 800 ℃ high temperature environment can be stable to maintain its mechanical properties. 9.

9. Corrosion resistance: in the oxidation and corrosion environment, especially in the repeated rolling and squeezing off the surface of the oil film in the contact area should have oxidation and corrosion stability.

Industrial silicon nitride ceramic materials and bearing steel sex ability

Density(Kg/m3) 3250 7800 Young's modulus(GPa) 310 210 Compressive strength(MPa) >3500

Modulus of rupture (MPa) 700-1000 Vickers hardness (GPa) 14-18 8 Toughness (MPa- m1/2) 5-8 16-20
Coefficient of thermal expansion (×10-2/°K) 3 12 Thermal conductivity (W/mK) 20 30 Specific heat (J/KgK) 800 450

Upper service temperature (°K) 1050 400-600 Thermal shock resistance High Very high Rolling contact fatigue failure form Flaking Flaking

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