Whether for aluminum extrusion radiator or heat pipe radiator, fan is the soul of heat dissipation. Speaking of fans, I believe that everyone will soon associate them with features such as silence, air volume and service life. It is the bearing type that determines whether the fan is silent, the air volume and the service life, so don't underestimate the fan bearing. Because there is a lot of knowledge in it, it is essential to know the characteristics of bearings if you want to choose a cooling fan that meets your own needs. ?
Because different bearings have different performance effects, we can't generalize, let alone hearsay. After studying hard, you may be more interested in fan bearings and become an expert in this field. In order to facilitate everyone to learn and understand the characteristics of various types of fan bearings, the author specially collected and sorted out a large number of bearing information (the bearing explanation in this paper was taken from Baidu search) to share with netizens. If there is anything wrong, please correct me, and players with better information sources are also welcome to reply in the comments.
Bearing type refers to the bearing type used by air-cooled radiator fan. In mechanical engineering, there are many kinds of bearings, but only a few are used in radiator products: sliding friction oil-bearing (sleeve bearing), rolling friction ball bearing and the mixture of the two bearing forms.
In recent years, the new technologies introduced by major radiator manufacturers in bearings, such as nano-ceramic bearings and Frye bearings, are also improved on the basis of the above-mentioned basic forms of bearings, and their working principles have not changed. Ordinary air-cooled radiator mainly adopts oil-bearing and ball bearing.
Oil-bearing is a sleeve bearing with sliding friction, and lubricating oil is used as lubricant and drag reducer. Although the noise is low and the manufacturing cost is low, it is seriously worn and its service life is far from that of ball bearings. Moreover, after a long period of use, due to the oil seal, the lubricating oil will gradually evaporate, and dust will also enter the bearing, causing problems such as slower fan speed and increased noise. Continue to refuel or get a new one.
Ball bearings change the friction mode of bearings and adopt rolling friction, which effectively reduces the friction phenomenon between bearing surfaces, effectively prolongs the service life of fan bearings and therefore prolongs the service life of radiators. The disadvantage is that the process is more complicated, resulting in higher cost and higher working noise.
Current magnetic bearing (magnetic? Bearing) is popular, but it can't be regarded as a separate bearing method. Because its specific application has to cooperate with other bearing forms, such as magnetic suspension+ball bearing, magnetic suspension+oil bearing, magnetic suspension+vaporization bearing and so on. Magnetic bearings suspend the rotor in the air by magnetic force, so there is no mechanical contact between the rotor and the stator. Compared with traditional ball bearings and oil-bearing bearings, magnetic bearings have no mechanical contact, and the rotor can run at a very high speed, which has the advantages of low mechanical wear, low energy consumption, low noise, long service life, no lubrication and no oil pollution, and is especially suitable for special environments such as high speed, vacuum and ultra-clean.
Two. Detailed description of bearing type
In recent years, the new bearing technologies introduced by major radiator manufacturers, such as magnetic bearing, fluid protection system bearing, hydraulic bearing, Frye bearing and nano-ceramic bearing, are also improved on the basis of the above basic bearing forms, and the basic working principle has not changed. ?
●? oil-retaining bearing
Ordinary oil-bearing is full of oil.
Traditional oily oil is easy to volatilize and be polluted by dust.
Oil bearing (sleeve? Bearing)? It is a sleeve bearing with sliding friction, and lubricating oil is used as lubricant and drag reducer. In the initial use, the running noise is low and the manufacturing cost is low, but this kind of bearing is seriously worn and its service life is far from that of ball bearing. Moreover, after the bearing is used for a long time, due to the oil seal (it is impossible to use high-grade oil seal for computer radiator products, usually ordinary paper oil seal), the lubricating oil will gradually evaporate, and dust will also enter the bearing, thus causing problems such as slow fan speed and increased noise, and bearing wear will lead to serious vibration of the eccentric fan. When these phenomena occur, either open the oil seal to refuel, or only eliminate it and buy a new fan.
Examples of oils
The sintered body made of powder metallurgy with metal powder as the main raw material is porous and has the technical advantage of freely adjusting the number, size, shape and distribution of pores in the manufacturing process. ? Using the porosity of the sintered body, 10%-40% (volume fraction) lubricating oil was impregnated and used in the state of self-oil supply. When the bearing temperature rises during operation, because the expansion coefficient of oil is larger than that of metal, it automatically enters the sliding surface to lubricate the bearing. When it stops working, the oil is sucked back into the air hole with the temperature drop.
Oil-bearing has the characteristics of low cost, shock absorption, low noise and no need to add lubricating oil when working for a long time, and is especially suitable for working environments where lubrication is difficult or oil pollution is not allowed. Porosity is an important parameter of oil-bearing and oil-bearing working at high speed and light load requires high oil content and porosity. Oil-bearing working under low speed and heavy load requires high strength and low porosity. This kind of bearing was invented in the early 20th century, and it has been widely used because of its low manufacturing cost and convenient use. Now it has become an indispensable basic component for the development of industrial products such as automobiles, household appliances, audio equipment, office equipment, agricultural machinery and precision machinery.
Oily bearings are divided into copper-based bearings, iron-based bearings and copper-based bearings.
●? Single ball bearing
Example of single ball bearing principle
Single ball bearing (1? Ball+1? Sleeves Bearing)? It is an improvement on the traditional oil-bearing and adopts a mixed form of sliding friction and rolling friction. In fact, it is to use a ball bearing with an oil-bearing to reduce the cost of double ball bearings. Rotor and stator are lubricated with balls and equipped with lubricating oil. It overcomes the shortcomings of short service life and unstable operation of oil-bearing and the cost increase is extremely limited. Single ball bearing absorbs the advantages of oil-bearing and double ball bearing, and improves the service life of bearing to 40000 hours. The disadvantage is that the running noise increases after adding the ball, but it is still less than that of the double ball bearing.
Low noise and long service life are the characteristics of single ball bearing, which overcomes the shortcomings of high noise, high cost and great difficulty of double ball bearing. It inherits the advantages of long service life of double balls and absorbs the advantages of low noise of oil-sealed bearings, so it can be said that it is the first choice for low-cost bearings. Comparable to it is the hydraulic bearing, which has a service life of 40,000 ~ 50,000 hours. The advantage is that the noise will not increase after long-term use, and no lubricating oil is needed. The noise of a single ball bearing increases slightly after long-term use, which can be solved by adding grease. But no hydraulic bearing is used, so the hydraulic bearing is difficult and expensive.
●? Double ball bearing
Example of double ball bearing principle
Fully enclosed ball bearing
Double ball bearing (2? Ball? Bearing)? Belonging to a relatively high-grade bearing. It adopts two ball bearings with rolling friction. There are several tiny steel balls around the axis of the bearing. When the fan blade or axis rotates, the steel ball rotates with it. Because they are all spheres, the friction is small, and there is no problem of oil leakage. The advantage of double ball bearings is long service life, about 50000- 100000 hours. Good anti-aging performance, suitable for high-speed running fans.
The disadvantage of double ball bearings is high manufacturing cost and the maximum noise at the same speed level. Double ball bearings and hydraulic bearings have good sealing performance, especially double ball bearings. Double ball bearings are completely embedded in the fan, and the rotating parts are not in direct contact with the outside world. In a sealed environment, the working environment of the bearing is relatively stable. Therefore, almost all 5000 rpm large-caliber fans use double ball bearings. But the hydraulic bearing has a unique oil return circuit, so the possibility of lubricating oil leakage is very small, so don't worry too much.
Three. Oily bearing family
★? hydraulic bearing
Hydraulic bearings represent AVC fans.
Hydraulic bearing (hydraulic? Bearing)? It was initiated by AVC, which is an improved technology based on the fact that the oil-bearing hydraulic bearing has more oil storage space than the oil-bearing bearing and has a unique loop-back oil supply circuit. The working noise of the hydraulic bearing fan is obviously reduced, and its service life is very long, reaching 40,000 hours. Hydraulic bearings are essentially oil-bearing bearings. However, after improvement, the life of this kind of oil-sealed bearing is much longer than that of ordinary oil-sealed bearing, and it inherits the advantages of oil-filled bearing-low running noise. At present, hydraulic bearings have been applied to AVC radiators, but not all AVC radiators use hydraulic bearing fans.
★? Rifle position
Cool radiator adopts Frye bearing.
On the left is the oil-bearing and on the right is the Frye bearing.
Frye bearing (rifle? Bearing)? The representative manufacturer of technology is CoolerMaster. At present, CoolerMaster has upgraded most traditional oil-bearing fans to Xinfu bearings. As an improvement of traditional oil-bearing, Frye bearing is made of wear-resistant materials, which reduces the friction between bearing and shaft core. Frye bearing also has a shaft core with reverse spiral groove and oil retaining groove. When the fan runs, it will form reverse deviation to avoid oil loss and prolong the bearing life. By adopting the above structure and components, the Frye bearing fan greatly improves the bearing and oil retaining capacity and reduces the noise.
★? Fluid dynamic bearing
Sickle fans prefer to use hydrodynamic bearings.
Fluid dynamic bearing
Example of fluid dynamic bearings
Hydrodynamic bearing (Hypro? Bearing)? Its name comes from HY (fluid mechanics? Wave, hydrodynamic wave) PRO (oil? Protection? The system (oil protection system) is a patented product of ADDA, a well-known radiator and fan manufacturer. It is also improved many times on the basis of traditional oil-containing fluid dynamic bearings and hydraulic bearings, which can be described as the same goal. Both designs adopt some unique improvement measures, but they are essentially circulating oil systems, and their performances are basically the same in all aspects. Usually, the product life can reach more than 50,000 hours.
★? Nano ceramic bearing
Foxconn radiator takes the lead in launching nano-ceramic bearings.
The appearance of nano-ceramic bearings
Nano-ceramic bearing (nano? Ceramics? Bearing, NCB)? In essence, Foxconn is the first oil-bearing in its products. The traditional oil-containing fan is seriously worn in use and has low reliability in long-term use. Nano-bearing effectively overcomes this problem, and ceramic bearing technology fully integrates special polymer materials and special additives.
Example of nano-ceramic bearing
Nano-zirconia particles under microscope
The bearing core is made of special titanium dioxide material by stamping die and sintering process. The crystal particles are reduced from 60um to 0.3um, which has the characteristics of firmness, smoothness and wear resistance. Nano-ceramic bearing has strong high temperature resistance and non-volatilization, which greatly prolongs the service life of the fan. The properties of nano bearings are similar to ceramics, and the more they are ground, the smoother they become. According to the test, the average service life of fans with nano-ceramic bearings is more than 654.38+0.5 million hours. This technology is not a real nano-technology, and the materials used are not real nano-materials, but the word nano is used to attract people's attention.
Physical properties of nano-zirconia
Nano-zirconia powder has the characteristics of greatly reducing sintering temperature, high hardness and high strength. The thermal expansion coefficient, friction coefficient, density, hardness and other parameters are much higher than bronze and bearing steel used in oil-sealed bearings and ball bearings, and some parameters even reach the level of diamond coefficient. Using these characteristics, the nano-ceramic bearing itself can make the density very small, expand the high temperature resistance, and has the characteristics of strong insulation, compression resistance, oxidation resistance and corrosion resistance, which is far ahead of the production of traditional process fans.
The traditional oil seal bearing fan is seriously worn in use and has a short service life. Moreover, with the increase of temperature, it is easy to cause the internal heat to expand and get stuck in the axis, and the fan speed will decrease or even stop, which is extremely dangerous for the chips of various devices. However, the fan with nano-ceramic bearing has very strong high temperature resistance, and the nano-particle lubricant does not volatilize, which doubles the life of the fan with nano-ceramic bearing.
Compared with the ball bearing fan, the noise of the nano-ceramic bearing fan is also well controlled, and the noise generated is 2-3 dB lower than that of the double ball bearing fan. The assembly process of nano-ceramic bearing fan is much simpler than that of ball bearing fan, which virtually improves the quality and reduces the cost. Due to the small size of nano-ceramic bearing, the winding of motor can be lengthened in the design of fan, thus improving power and speed. Compared with the ball bearing fan, its central area is smaller, which effectively increases the space area of blades and increases the air circulation.
Fourthly, the ultra-static magnetic bearing.
Magnetic bearing?
An Naimei fan adopts magnetic bearings.
Magnetic suspension bearing structure
Magnetic bearing (magnetic? Bearing)? The rotor is suspended in the air by magnetic force, so there is no mechanical contact between the rotor and the stator. Its principle is that the magnetic induction line is perpendicular to the magnetic levitation line and the shaft core is parallel to the magnetic levitation line, so that the weight of the rotor is fixed on the running track and supported in the direction of the anti-magnetic levitation line by the almost empty shaft core, forming the whole rotor suspended on the fixed running track. Compared with traditional ball bearings and oil-bearing bearings, magnetic bearings have no mechanical contact, and the rotor can run at a very high speed, which has the advantages of low mechanical wear, low energy consumption, low noise, long service life, no lubrication and no oil pollution, and is especially suitable for special environments such as high speed, vacuum and ultra-clean. In fact, magnetic levitation is only an auxiliary function, not an independent bearing form. The specific application must cooperate with other bearing forms, such as magnetic suspension+ball bearing, magnetic suspension+oil bearing, magnetic suspension+vaporization bearing and so on. This technology has not been recognized by European and American countries.
Working principle of magnetic bearing
Active magnetic bearing principle
Take a simple magnetic levitation system as an example, it consists of four parts: rotor, sensor, controller and actuator, in which the actuator includes electromagnet and power amplifier. Assuming that the rotor is disturbed downwards at the reference position, it will deviate from its reference position. At this time, the sensor detects the displacement of the rotor from the reference point, and the microprocessor as the controller converts the detected displacement into a control signal, and then the power amplifier converts this control signal into a control current, and the control current generates a magnetic force in the actuator magnet, thereby driving the rotor back to the original equilibrium position. Therefore, no matter whether the rotor is disturbed downward or upward, the rotor can always be in a stable equilibrium state.
Magnetic bearing (magnetic? Bearing)? The motor adopts magnetic levitation (magnetic? System, MS) design, its magnetic induction line is perpendicular to the maglev line, so the shaft core is parallel to the maglev line, so the weight of the rotor is fixed on the running track, and the almost empty shaft core is used to support the anti-maglev line, forming the whole rotor suspended on the fixed running track. Therefore, magnetic levitation is actually only an auxiliary function, not an independent bearing form. The specific application must be matched with other bearing forms, such as magnetic suspension+ball bearing, magnetic suspension+oil bearing, magnetic suspension+vaporization bearing and so on. This technology has not been recognized by European and American countries.
★? Vapo bearing
ASUS Lion King radiator adopts vapo vaporizing bearing.
Vaporization bearing (VAPO? Bearing)? Sunon improved the magnetic levitation technology, that is, strengthened the hardness of the sleeve of the oil-bearing and specially treated the inner surface of the sleeve, thus overcoming the shortcoming that the oil-bearing is not resistant to high temperature. Combined with magnetic levitation technology, the service life is greatly prolonged.
With the development of control theory and the continuous improvement of performance requirements of magnetic bearing system, the complexity of the control algorithm that the controller of magnetic bearing system needs to realize is getting higher and higher. Although the traditional analog controller has the advantages of low cost, high speed, stable performance and good adaptability to PID control algorithm, it is difficult to meet the growing needs of users. Therefore, digital control has become the mainstream trend of magnetic axis system control. SUNON in Taiwan Province Province mainly produces SUNON magnetic levitation VAPO bearing fans.
★? Special individual external magnetic bearing
External magnetic fan appearance
Internal structure of external magnetic fan
The external magnetic (T.M.D) fan is characterized by moving the motor around the frame, and the center is only supported by a small bearing. The benefits are obvious: the wind area is increased and the blind area is greatly reduced. It is said that this design can increase the air volume and static pressure by 30%, and because T.M.D technology also combines the patented blades with the outer guide ring, it can make the air flow more concentrated and reduce the generation of turbulence, thus improving the heat dissipation efficiency and reducing the noise by 5%. Generally speaking, the ball bearing is suitable, with low friction and long service life. There is nothing wrong with using hydraulic bearings, but the aging of bearings may slow down the starting speed and the service life is not as good as that of ball bearings.
Verb (abbreviation of verb) Comparison of bearing types
related data
Through comparison, it is not difficult to see that after continuous improvement and perfection, the huge oil-bearing family has been able to meet the mainstream application needs. At present, the most widely used hydraulic fan has a service life of 30,000-50,000 hours, which can fully meet the general application requirements. The mute effect is obviously better than the ball fan, so players don't have to blindly pursue the ball fan when purchasing fans. Moreover, the craftsmanship of fans is relatively difficult and the price is relatively expensive. However, for players who pursue longevity, they might as well buy a double-ball fan and a nano-ceramic bearing. For players who pursue ultra-quiet, it will be better to buy a magnetic levitation fan, but the disadvantage is that the process is difficult and the price is more expensive.
Summary:
Through the above introduction, it is not difficult to find that there are still many doorways to choose a small cooling fan. And sometimes life and mute, mute and cost, life and cost are not directly proportional, so we must pay more attention and distinguish when choosing. Don't ignore one thing, and of course don't miss the function you need most. It is suggested to choose according to the characteristics of consumption capacity, use environment and air volume.