CPU fan bearing classification

Oil-containing bearings
Oil-containing bearings (Sleeve Bearing) are the most commonly used cooling fan bearings. It uses lubricating oil as a lubricant and drag reducer. The advantage is that the price is very low and the operating noise is relatively low during the initial use. The disadvantage is that the bearing is easy to wear and has a short life. In addition, after this type of bearing is used for a long time, the lubricating oil in the bearing sleeve is easy to leak out, the noise increases, and it will pollute the motherboard and other accessories.
Dual Ball Bearings
Dual Ball Bearings (Dual Ball Bearing or Two Ball Bearing) use two ball bearings and use rolling friction instead of traditional sliding friction, so the friction is small, no lubricating oil is required, and there is no problem of oil leakage. Its advantages are very long service life, good anti-aging performance, and suitable for fans with higher speeds. The disadvantages are high manufacturing costs and the highest noise.
Single Ball Bearings
Single Ball Bearings (ONE Ball Bearing or Ball+Sleeve Bearing) are an improvement on traditional oil-containing bearings. It uses a mixture of sliding friction and rolling friction, using one ball bearing + one oil-containing bearing to reduce the cost of double ball bearings. It combines the advantages of oil-containing bearings and double ball bearings. The disadvantage is that after adding balls, the running noise increases, but it is still less than double ball bearings.
Hydraulic bearings
Hydraulic bearings are improved on the basis of oil-containing bearings. Hydraulic bearings use a unique ring-type oil supply circuit, which greatly reduces the problem of oil leakage. The service life is greatly extended compared with ordinary oil-containing bearings, and it inherits the advantages of oil-containing bearings: low running noise. Hydraulic bearings have been widely used in AVC radiators.
Rifle bearings
Rifle bearings are mainly used for CoolerMaster's cooling fans, and are also an improvement on traditional oil-containing bearings. Rifle bearings are made of wear-resistant materials to make high-oil hollow bearings, and also have a shaft core with reverse spiral grooves and oil retaining grooves. When the fan is running, the lubricating oil in it will form a reverse reflux, thereby avoiding oil leakage problems and keeping the running noise very small.
Magnetic bearings
Magnetic bearings are new types of bearings that use magnetic force to achieve non-contact. They have a series of excellent qualities such as non-contact, no need for lubrication and sealing, low vibration, long service life, and low maintenance costs. They belong to the field of high technology. Those who have used oil-sealed bearings know that after a period of time, the fan noise becomes louder. At this time, it is necessary to add lubricating oil to the fan bearing, which is not something that ordinary users can do and is troublesome. Ball bearings also have this weakness, but magnetic bearings are different. This type of bearing is used in Anmei fans.
In addition, there are nano bearings (NACOOL Bearing), nano ceramic bearings (NANO Ceramic Bearing), fluid protection system bearings (Hypro Bearing), etc., but they are more expensive and less common in the market.