Ceramic Bearings
Ceramic Bearings
Ceramic bearings have the following advantages:
1, Long life and wear resistance - the life expectancy of all ceramic bearing is 10-50 times longer than the life expectancy of all-steel bearings. The life of hybrid ceramic bearings is 3-5 times longer than full-bearing steel bearings.
2, 60% lighter than steel and 2 times of high temperature hardness than steel.
3, Corrosion resistance - As the ceramic material is the inert material, it is more resistant to corrosion and wear.
4, Rigidity - Because of the high elastic modulus of ceramic materials, its rigidity is 50-55% more than ordinary steel bearings.
5, High temperature - All ceramic bearings can be used in the environment with a temperature more than 500 。C.
6, Low torque - According to the structure, the ceramic bearing torque is reduced by about 1/3;
7, Non-magnetic and non-conductive.
Full Ceramic Bearings made with ZrO2
All ceramic bearings with anti-magnetic electrical insulation, wear resistance, corrosion resistance, oil-free self-lubricating, high temperature and cold tolerance characteristics can be used for extreme harsh environments and special conditions. The rings and the rolling element are made of zirconia (Zr02) and the retainer is made of PTFE (PTEE) as the standard equipment. Generally, the glass fiber reinforced nylon 66 (GPRA 66-25) and special engineering plastics
Full Ceramic Bearings made with SisN4
The rings and rolling elements of silicon nitride all-ceramic bearing are made of silicon oxide (Si3N4) ceramic material and with PTFE retainer as a standard equipment. Generally, the glass fiber reinforced nylon 66 (GPRA 66-25) and special engineering plastics (PEEK , PI) are also available. Comparing to Zr02 material, Si3N4 all-ceramic bearing is more applicable to higher speed and load capacity, and used in higher temperature environment. At the same time, it can be provided to be used on a axle required a high-speed high-precision high-rigidity precision bearing.
Full Ceramic Ball Bearings w/o cage
Due to the non-cage structure design, more ceramic balls loaded than the standard structure bearing is to enhancing its radial load capacity. In addition, it also can avoid the cage material constraints to achieve anti-corrosion and temperature resistance effects of the ceramic cage type all-ceramic bearings. However, the series is not suitable for a high-speed condition. Pay attention when the installation, the the gap surface is not installed in the axial load end. As the inner and outer ring of bearing with a ball gap, the bearing is not suitable for a larger axial load applications.
Full Ceramic bearings with Ceramic cage
Ceramic cage has the advantages of wear-resistant, high strength, corrosion-resistant and self-lubricating. The all-ceramic bearings with a ceramic cage can be used in the condition of strong corrosion, high temperature and high vacuum and other harsh environments. Commonly, Zr02 is used as the material of ceramic cage.
Properties comparison of ceramic materials
Technical data | Unit | B4C | 99A12O3 | ZTA-20% | ZrO2 | Si3N4 | Sic |
Density ρ | g/cm3 | 2.4-2.51 | 3.7-3.99 | 5.5 | 6 | 3.2 | 3.2 |
HV Hardness | kg/mm | 2700-3200 | 2300-2700 | 1470-1500 | 1300-1500 | 1700-2700 | 2350-2450 |
Flexural strength σs | Mpa | 350-400 | 300-400 | 700 | 1000-1500 | 900 | 450-800 |
Indentation strength | Mpa | 1800-2500 | 2800-3500 | 2000 | 2000 | 3500 | 2250-3000 |
Impact strength Kc | Map.m-3/2 | 6 | 2-4 | 5-6 | 11 | 7 | 4-5 |
Weber modulus | Gpa | >7 | >10 | >15 | >15 | >6 | |
Et. modulus of elastcity | Gpa | 407 | 260 | 210 | 320 | 410 | |
Poisson ratio | 0.2 | 0.23 | 0.3 | 0.26 | 0.16 | ||
Coefficient of expansion α | x10-6/℃ | 4.5 | 6.5-8.6 | 9.4 | 10.5 | 3.2 | 4.3 |
Heat Impact | △T℃ | 200 | 470 | 250 | 500 | 350 | |
Resistivity | CM2 | 0.3-0.8 | >1014-1016 | >1010 | >1010 | >1014 | 100~2 |
All-ceramic bearings made with ZrO2