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As social progress and science and technology of high-speed development, KOYO bearings of using environment and conditions increasingly diversification, on bearing of structure, and material and performance of requirements also increasingly high, some hi-tech area and some special environment Xia work of machinery, as aviation space, and nuclear energy, and metallurgical, and chemical, and oil, and instrument, and machinery, and electronic, and textile, and pharmaceutical, industrial, needs in high temperature, and high-speed, and high precision, and vacuum, and no magnetic, and no oil lubrication, and acid, and alkali, special environment Xia work. Rely solely on these new requirements on improved structures of traditional metal bearings or improve lubricating conditions are far from enough to meet, had to develop new material, fundamental breakthroughs and innovations. Studies have found some ceramic materials with excellent performance at home and abroad, to withstand harsh metal and polymer materials to competent working environment, and has required all the important characteristics of bearing materials, manufacturing of ceramic materials should therefore be used for bearings, has become the world's high-tech development and application of hot spots, become a symbol of mechanical material revolution.
Silicon nitride ceramic bearings are mainly used in 4 areas: 1, high speed bearings, 2, high temperature bearings, bearings for 3, vacuum, 4, bearing corrosion. Silicon nitride ceramic bearings are able to work under special circumstances and conditions, fully benefit from the performance of silicon nitride ceramic. Silicon nitride ceramic bearing has the following advantages:
1, high speed
Ceramics only equal steel weight 40% weight, density, a characteristic, KOYO bearings lightweight and high speed can be realized, so that when the ceramic bearings in high speed rotating inhibition caused by the centrifugal force of the rolling load increases and slipping, Ceramic bearing of speed is steel system bearing of 1.3~1.5 times, its DN value can up 3 million, such as corner contact ball bearing, due to has must of contact corner, its scroll body and roll road surface Zhijian will produced rotating sliding, dang used density small of ceramic scroll body Shi, not only rotating sliding small, and on bearing fever and surface injury are up to useful of role, for aviation space aircraft is very useful of.
2, high rigidity
Young's modulus of silicon nitride ceramic much higher than metal, metal of 1.5 times, thus after the force of the elastic deformation is small, relative load of high rigidity, can increase stiffness around 15%~20%, so as to reduce the vibrations of machine tools. High precision application system to get a good value, such as the ultra precision machine tool spindles, high-precision aerospace bearings.
3, long life
Due to low dislocation of ceramics, low migration rates, and has a higher hardness, higher hardness than the metal 1 time more than doubled, to reduce wear and wear resistance of ceramic bearings are good. Also, nitride Silicon ceramic of machinery strength does not low, its tensile strength and anti-bent strength and metal quite; and compressive strength very high, about is metal of 5~7 times, especially in high temperature conditions Xia, still can keep high of strength and hardness, even in 1200 ℃ Shi strength also basic keep not variable, in has foreign body mixed with of situation Xia, ceramic ball rarely produced peeling failure, therefore, resistance pressure marks sexual good of ceramic bearing usually has more long of life, General more steel system bearing improve 3~5 times.
4, low fever
Due to less friction coefficient of silicon nitride ceramic materials, is about 30% of standard bearing steel, so compared with the metal, the poor thermal conductivity of silicon nitride ceramics, ceramic bearing the heat generated when a smaller, you can extend the life of the grease.
5, low thermal expansion
Thermal expansion coefficient of silicon nitride ceramics is about 20% of bearing steel, so small amount of ceramic bearing size change over temperature and lower heat generated by a preload, thus avoiding excessive heat gathered into fatigue spalling failure, useful in environments where temperature changes.
6, corrosion resistance
Inactive chemical properties of ceramic materials, ceramic bearings have a certain degree of corrosion resistance and, therefore, ceramic bearings for steel KOYO bearings fail prematurely due to lack of chemical resistance of all applications, such as chemical machinery, food machinery, Marine Department use and application of atomic energy equipment.
7, no magnetic
In a strong magnetic field environment, when using steel bearings, worn down by powder adsorption from the bearing itself between the rolling elements and raceways, bearing damage of falling off in advance, the main cause of increased noise due to ceramic bearings are completely non-magnetic, and have a good carrying capacity, so can be used to require a full non-magnetic bearing for the occasion.
8, insulation
Annealing resistance of ceramic materials is high, as better insulation, the bearing from arc damage.
In short, with ceramic material bearing can be greatly expanded range of applications in various fields of rolling bearings. World research, production and sales of ceramic bearing company a lot, but mostly for hybrid bearings, bearing rolling elements for ceramic materials, inner and outer rings for steel materials. Study on ceramic bearings in China started late, countries starting from 85 to include research and development of ceramic ball bearing technology research projects, and to inject large amounts of capital, a number of research institutes and enterprises have also made useful exploration, has had good results, but it is still in the study stage. Effects of ceramic ball bearings are widely used mainly because it is difficult to process and excessive manufacturing costs. Processing speed compared with the existing technology to improve more than 1 time, the technical indicators have reached or exceeded the G5 standards. On China's industrialization and commercialization of ceramic bearing process may play a role. Of course, research on ceramic bearings in the early stages, their research is far from over, and further research is needed in the following areas, explore:
Research scope is wider, lubricated ceramic bearings under rolling contact conditions even worse condition;
Second is the study of ceramic bearing part of the structure with the design, as well as reliability and economy of processing;
Three related parts nondestructive testing method bearing are ceramic and damage prediction technology;
Four is the development of ceramic bearing inspection standards.
Believe entered the practical stage of ceramic bearing is not too long, its prospects are very broad, and some even predicted: Ceramic bearing and will completely replace the steel bearing.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 7336BDB NSK | 180 | 380 | 75 |
| 7336ADB NSK | 180 | 380 | 75 |