According to the formation mechanism of the grinding surface of the FAG bearing working surface, the main factors affecting the grinding of the metamorphic layer are the effects of grinding heat and grinding force. Let's analyze the reasons for the failure of cylindrical roller bearings.
1. The main purpose of preloading: The main purpose and representative examples of preloading can be exemplified by some examples:
(1) While accurately determining the position of the radial direction and the axial direction of the shaft, the runout of the shaft is suppressed.
(2) Improve the rigidity of the FAG bearing. Bearings for the main shaft of the machine tool, bearings for the differential gears of the bicycle differential mechanism.
(3) Prevent vibration in the axial direction and abnormal sound due to resonance. Bearings for small motors.
For the cylindrical roller bearing subjected to the combined load, the number of rolling elements under load increases, the frictional resistance increases, the amount of fever increases, the lubrication and cooling conditions become worse, and the force acting on the cage also increases, so According to the FAG bearing type and the load angle, the limit speed of the bearing must be multiplied by a reduction factor f2 to adjust.
If the limit speed of the selected cylindrical roller bearing is not satisfactory for the application, some improved techniques can be used to improve the request to reach a more satisfactory request. Such as improving the bearing tolerance difference; properly increase the clearance; use special materials and improve the structure of the support frame; change the lubrication method, such as oil and gas, oil mist and jet lubrication; improve cooling conditions.
Temperature rise is likely to occur during the use of FAG bearings. When the temperature of the cylindrical roller bearing rises, first judge whether it is wrong or not. If it is really raised, it should be done as follows
deal with:
(1). Check the cooling water pressure, water flow and piping system are normal. If the water pressure is low, the filter may be clogged and cannot be disposed of in time. It can be shut down and put into use when it is confirmed that it can work.
(2). Check the oil pressure of the governor. If the oil pressure is low, the cooling water hydraulic valve may be closed.
(3). Check if the FAG bearing has abnormal sound and check if the cylindrical roller bearing swing is abnormal.
(4). Take an oil sample to see if there is any change in the oil color and test it to see if it has deteriorated. If deterioration is confirmed, stop replacing the new oil.
(5). Check if the oil level is normal. If it is not normal, check if the oil drain valve is closed. If it is closed, it should be replenished. If the gasket is oily, stop it.
2018年12月18日星期二
Characteristics and classification of NSK magnetic bearings
Magnetic bearings are a new type of bearing. The specific information is not very detailed at the moment. Today, we will introduce the characteristics and classification of magnetic NSK bearings. A magnetic bearing is a form of support that supports a load or a suspended rotor by magnetic force. In recent years, such bearings have developed rapidly, especially in high speed, low friction, high (low) temperature and vacuum applications. Compared to other forms of support, magnetic bearings have unique advantages and are promising.
First, characteristics and classification
1. Features 1. Low friction, low power consumption, and ultra-high speed operation. 2, the bearing precision is high, the operation is stable and reliable. 3 can be operated in high temperature, deep cold and vacuum environment. 4 The structure is complex, demanding, and has magnetic interference to the environment, but no other pollution.
2. Classification magnetic bearings are classified according to their control methods, magnetic energy and structural forms. In addition, according to the type of magnetic field can be divided into permanent magnet type, electromagnetic type and permanent magnet - electromagnetic hybrid type. Depending on the type of bearing suspension force, it can also be divided into suction and repellent. Superconducting magnetic bearings are also classified into low temperature superconducting and high temperature superconducting. There are some special restrictions between the different types in the above categories, so special attention should be paid. 1 permanent magnet type bearing can only be passive (passive type), while passive type bearing is impossible
3. It is stable in all directions and at least one direction should be active. 2 DC excitation bearings can only be effective (effective). 3 pure electromagnet bearings can only be 5 degrees of freedom control type bearings, their volume, quality and power consumption are relatively large. 4 Repelling magnetic bearings, due to the low magnetic susceptibility, the structure is more attractive than the suction type and is rarely used.
First, characteristics and classification
1. Features 1. Low friction, low power consumption, and ultra-high speed operation. 2, the bearing precision is high, the operation is stable and reliable. 3 can be operated in high temperature, deep cold and vacuum environment. 4 The structure is complex, demanding, and has magnetic interference to the environment, but no other pollution.
2. Classification magnetic bearings are classified according to their control methods, magnetic energy and structural forms. In addition, according to the type of magnetic field can be divided into permanent magnet type, electromagnetic type and permanent magnet - electromagnetic hybrid type. Depending on the type of bearing suspension force, it can also be divided into suction and repellent. Superconducting magnetic bearings are also classified into low temperature superconducting and high temperature superconducting. There are some special restrictions between the different types in the above categories, so special attention should be paid. 1 permanent magnet type bearing can only be passive (passive type), while passive type bearing is impossible
3. It is stable in all directions and at least one direction should be active. 2 DC excitation bearings can only be effective (effective). 3 pure electromagnet bearings can only be 5 degrees of freedom control type bearings, their volume, quality and power consumption are relatively large. 4 Repelling magnetic bearings, due to the low magnetic susceptibility, the structure is more attractive than the suction type and is rarely used.
2018年12月14日星期五
Bearing special measuring tool
In order to ensure product quality and improve inspection efficiency, a large number of special measuring tools are used in the whole process of inspecting the bearings. Among them, the most used ones are special standard parts.
1. Common standard parts
At present, the standard parts used in each bearing factory are of different origins. The factory with conditions is manufactured by the machine repair (tool) workshop of the factory, and only some standard parts such as groove diameter standard parts are selected from the production parts. In addition to outsourcing or self-made parts, factories that do not have the conditions are selected from the production parts. In general, the precision of the specially manufactured standard parts is high, and the precision selected from the production parts as the standard parts is lower, but as long as the reasonable and correct selection, the quality requirements of the bearing parts products can be guaranteed. The selection of measuring tools is the task of measurement. They regularly and regularly check the performance of the measuring tools. As the user, the measuring tools and the instrument usage system must be strictly observed.
In addition to the reference parts of the measuring room, the standard parts used by our company in the production workshop are basically selected from the production parts. After passing the verification of the measuring room according to the technical conditions, they can be used as standard parts. At the time of the inspection, the manufacturing part is marked with the manufacturing size and number of the standard part. The actual size of the standard part is based on the standard part of the issued standard part verification card. In addition, the "|" mark on the outer diameter or end face of the standard part is indicated, which indicates the position of the measuring point of the standard part, so the tip of the meter (or the fulcrum corresponding to the tip) must be placed when the table is adjusted. On the "|" mark.
1) Width standard parts
The width standard is used to verify the width of the inner and outer rings of the bearing. The width standard is matched with the G903 series of measuring instruments and instruments to measure the width of the ferrule. No damage, burrs, etc. are allowed on the working surface of the standard parts. There are bumps and burrs on a working surface, which must be re-checked to avoid measurement errors.
2) Inner diameter and outer diameter standard parts
The inner and outer diameter standard parts are used to inspect the bearing inner diameter and outer diameter dimensions, respectively. The inner diameter and outer diameter of the bearing are the main dimensions of the bearing and are one of the important items that determine the quality of the bearing. Therefore, the verification of the inner and outer diameter standard parts must be accurate.
The inner diameter standard is matched with the D923 series inner diameter measuring instrument and instrument to measure the inner diameter, the inner diameter variation in a single radial plane, and the inner ring reference end to the inner diameter. The outer diameter standard is matched with the D913 series outer diameter measuring instrument and instrument to measure the outer diameter size, the outer diameter variation in a single radial plane, and the variation of the outer diameter surface busbar to the reference end surface inclination.
3) Ditch diameter standard parts
The inner groove diameter and the outer groove diameter standard are used to inspect the inner and outer ring channel diameters of the bearing, respectively. The groove diameter, groove curvature, groove symmetry, and single radial in-plane groove diameter change are selected from the product. Items such as quantity must be qualified. The channel standard parts are divided into inner and outer groove standard parts.
The inner channel standard is matched with the D022 series internal groove measuring instrument and instrument. It can be used to measure the diameter of the inner ring channel and the variation of the inner channel diameter in a single radial plane. The outer channel standard is matched with the D012 series outer groove measuring instrument and instrument, and can be used to measure the outer ring channel diameter size, the variation of the inner and outer channel diameters in a single radial plane, and the like.
4) Clearance and vibration standard parts
The clearance and vibration standard are used to check the clearance and vibration of the bearing, respectively, and are selected from the product. The clearance standard is matched with the X092 series radial clearance gauge and instrument to measure the radial clearance of the bearing. The vibration standard is matched with the S0910 or BVT-1 vibration measuring instrument to measure the vibration acceleration (or speed) level of the bearing.
1. Common standard parts
At present, the standard parts used in each bearing factory are of different origins. The factory with conditions is manufactured by the machine repair (tool) workshop of the factory, and only some standard parts such as groove diameter standard parts are selected from the production parts. In addition to outsourcing or self-made parts, factories that do not have the conditions are selected from the production parts. In general, the precision of the specially manufactured standard parts is high, and the precision selected from the production parts as the standard parts is lower, but as long as the reasonable and correct selection, the quality requirements of the bearing parts products can be guaranteed. The selection of measuring tools is the task of measurement. They regularly and regularly check the performance of the measuring tools. As the user, the measuring tools and the instrument usage system must be strictly observed.
In addition to the reference parts of the measuring room, the standard parts used by our company in the production workshop are basically selected from the production parts. After passing the verification of the measuring room according to the technical conditions, they can be used as standard parts. At the time of the inspection, the manufacturing part is marked with the manufacturing size and number of the standard part. The actual size of the standard part is based on the standard part of the issued standard part verification card. In addition, the "|" mark on the outer diameter or end face of the standard part is indicated, which indicates the position of the measuring point of the standard part, so the tip of the meter (or the fulcrum corresponding to the tip) must be placed when the table is adjusted. On the "|" mark.
1) Width standard parts
The width standard is used to verify the width of the inner and outer rings of the bearing. The width standard is matched with the G903 series of measuring instruments and instruments to measure the width of the ferrule. No damage, burrs, etc. are allowed on the working surface of the standard parts. There are bumps and burrs on a working surface, which must be re-checked to avoid measurement errors.
2) Inner diameter and outer diameter standard parts
The inner and outer diameter standard parts are used to inspect the bearing inner diameter and outer diameter dimensions, respectively. The inner diameter and outer diameter of the bearing are the main dimensions of the bearing and are one of the important items that determine the quality of the bearing. Therefore, the verification of the inner and outer diameter standard parts must be accurate.
The inner diameter standard is matched with the D923 series inner diameter measuring instrument and instrument to measure the inner diameter, the inner diameter variation in a single radial plane, and the inner ring reference end to the inner diameter. The outer diameter standard is matched with the D913 series outer diameter measuring instrument and instrument to measure the outer diameter size, the outer diameter variation in a single radial plane, and the variation of the outer diameter surface busbar to the reference end surface inclination.
3) Ditch diameter standard parts
The inner groove diameter and the outer groove diameter standard are used to inspect the inner and outer ring channel diameters of the bearing, respectively. The groove diameter, groove curvature, groove symmetry, and single radial in-plane groove diameter change are selected from the product. Items such as quantity must be qualified. The channel standard parts are divided into inner and outer groove standard parts.
The inner channel standard is matched with the D022 series internal groove measuring instrument and instrument. It can be used to measure the diameter of the inner ring channel and the variation of the inner channel diameter in a single radial plane. The outer channel standard is matched with the D012 series outer groove measuring instrument and instrument, and can be used to measure the outer ring channel diameter size, the variation of the inner and outer channel diameters in a single radial plane, and the like.
4) Clearance and vibration standard parts
The clearance and vibration standard are used to check the clearance and vibration of the bearing, respectively, and are selected from the product. The clearance standard is matched with the X092 series radial clearance gauge and instrument to measure the radial clearance of the bearing. The vibration standard is matched with the S0910 or BVT-1 vibration measuring instrument to measure the vibration acceleration (or speed) level of the bearing.
2018年12月12日星期三
Rolling bearing cooperation
Basis for selecting a match
According to the rotation of the load acting on the bearing relative to the ferrule, the bearing ferrule can bear three kinds of loads: partial load, cyclic load, and oscillating load. Generally, the cyclic load (rotary load) and the oscillating load are tightly fitted; in addition to the special requirements of the local load, it is generally not suitable to use a tight fit. When the bearing ring is subjected to the holding load and is heavy, the inner and outer rings should be equipped with interference fit, but sometimes the outer ring can be loosened a little and should be able to swim axially in the housing hole of the bearing housing; When the bearing ring is subjected to the oscillating load and the load is light, a looser fit than the tight fit can be used.
Load size
The amount of interference between the bearing ring and the shaft or housing bore depends on the size of the load. When the load is heavy, a large interference fit is used. When the load is light, a small interference fit is used. Generally, when the radial load P is less than 0.07C, it is a light load, P is greater than 0.07C and equal to or less than 0. When 15C is normal load, P is greater than 0. When 15C is heavy load (C is the rated dynamic load of the bearing).
Operating temperature
When the bearing is running, the temperature of the ferrule is often higher than the temperature of the adjacent parts. Therefore, the inner ring of the bearing may loosen with the shaft due to thermal expansion, and the outer ring may affect the axial movement of the bearing in the housing hole due to thermal expansion. When choosing to cooperate, the temperature difference and expansion and contraction of the bearing device part should be taken into consideration. When the temperature difference is large, the interference between the selected shaft and the inner ring should be larger.
Rotation accuracy
When the bearing has high rotation accuracy requirements, in order to eliminate the effects of elastic deformation and vibration, the clearance fit should be avoided.
Structure and material of bearing housing hole
For the form housing hole, it is not advisable to use an interference fit when mating with the bearing outer ring, nor should the outer ring rotate in the housing hole. For bearings mounted on thin-walled housing bores, light metal housing bores or hollow shafts, a tighter fit than thick-walled housing bores, cast iron housing bores or solid shafts should be used.
Easy to install and disassemble
For heavy machinery, the bearings should be loose. When a tight fit is required, separate bearings, tapered bores and adapter sleeves or withdrawal sleeve bearings are available.
Axial displacement of the bearing
In the cooperation, when a ferrule of the bearing is required to be axially movable during operation, the outer ring of the bearing and the hole of the bearing housing should be loosely fitted.
Matching choice
The bearing and the shaft are matched by a base hole, and the coupling with the outer casing is made of a base shaft. The cooperation between the bearing and the shaft is different from the tolerance matching system used in the machine manufacturing industry. The tolerance of the inner diameter of the bearing is mostly less than zero. Therefore, under the condition of the same fit, the matching ratio of the inner diameter of the bearing to the shaft is generally tight. . Although the tolerance zone of the bearing outer diameter and the tolerance zone of the base shaft are below the zero line, the value is not the same as the general tolerance system.
According to the rotation of the load acting on the bearing relative to the ferrule, the bearing ferrule can bear three kinds of loads: partial load, cyclic load, and oscillating load. Generally, the cyclic load (rotary load) and the oscillating load are tightly fitted; in addition to the special requirements of the local load, it is generally not suitable to use a tight fit. When the bearing ring is subjected to the holding load and is heavy, the inner and outer rings should be equipped with interference fit, but sometimes the outer ring can be loosened a little and should be able to swim axially in the housing hole of the bearing housing; When the bearing ring is subjected to the oscillating load and the load is light, a looser fit than the tight fit can be used.
Load size
The amount of interference between the bearing ring and the shaft or housing bore depends on the size of the load. When the load is heavy, a large interference fit is used. When the load is light, a small interference fit is used. Generally, when the radial load P is less than 0.07C, it is a light load, P is greater than 0.07C and equal to or less than 0. When 15C is normal load, P is greater than 0. When 15C is heavy load (C is the rated dynamic load of the bearing).
Operating temperature
When the bearing is running, the temperature of the ferrule is often higher than the temperature of the adjacent parts. Therefore, the inner ring of the bearing may loosen with the shaft due to thermal expansion, and the outer ring may affect the axial movement of the bearing in the housing hole due to thermal expansion. When choosing to cooperate, the temperature difference and expansion and contraction of the bearing device part should be taken into consideration. When the temperature difference is large, the interference between the selected shaft and the inner ring should be larger.
Rotation accuracy
When the bearing has high rotation accuracy requirements, in order to eliminate the effects of elastic deformation and vibration, the clearance fit should be avoided.
Structure and material of bearing housing hole
For the form housing hole, it is not advisable to use an interference fit when mating with the bearing outer ring, nor should the outer ring rotate in the housing hole. For bearings mounted on thin-walled housing bores, light metal housing bores or hollow shafts, a tighter fit than thick-walled housing bores, cast iron housing bores or solid shafts should be used.
Easy to install and disassemble
For heavy machinery, the bearings should be loose. When a tight fit is required, separate bearings, tapered bores and adapter sleeves or withdrawal sleeve bearings are available.
Axial displacement of the bearing
In the cooperation, when a ferrule of the bearing is required to be axially movable during operation, the outer ring of the bearing and the hole of the bearing housing should be loosely fitted.
Matching choice
The bearing and the shaft are matched by a base hole, and the coupling with the outer casing is made of a base shaft. The cooperation between the bearing and the shaft is different from the tolerance matching system used in the machine manufacturing industry. The tolerance of the inner diameter of the bearing is mostly less than zero. Therefore, under the condition of the same fit, the matching ratio of the inner diameter of the bearing to the shaft is generally tight. . Although the tolerance zone of the bearing outer diameter and the tolerance zone of the base shaft are below the zero line, the value is not the same as the general tolerance system.
2018年12月8日星期六
Characteristics of bearing part structure
Raceway
The rolling bearing bears the surface of the load portion and serves as a rolling track for the rolling elements.
2. Straight raceway straight raceway
The busbars in a plane perpendicular to the rolling direction are straight raceways.
3. Convex raceway crowned raceway
A substantially cylindrical {TodayHot} or conical raceway with a continuous micro-convex curve in a plane perpendicular to the rolling direction to prevent stress concentration at the roller-to-handle contact.
4. Spherical raceway
The raceway is part of the surface of the ball.
5. channel raceway groove
The ball bearing raceway is grooved, usually a circular arc-shaped cross section with a radius slightly larger than the radius of the ball.
6. (groove) shoulder
The side of the groove (rolling).
7. rib rib
A narrow shoulder that protrudes parallel to the rolling direction of the raceway surface. It is used to support and guide the rolling elements and keep them in the bearing.
8. Guide the surface of the cage
A cylindrical surface of the bearing ring and washer for guiding the cage in the radial direction.
9. Ferrule (gasket) end face ring (washer) face
A ferrule (washer) surface perpendicular to the ferrule (washer) axis.
10. Bearing bore bearing bore {HotTag}
The inner bore of the inner ring or shaft of the rolling bearing.
11. Cylindrical bore
The inner bore of a bearing or bearing part has a straight line that is substantially straight and parallel to the bearing shaft line or the bearing part axis.
12. Conical inner bore
The inner bore of a bearing or bearing part has a straight line that is substantially straight and intersects the bearing shaft line or the bearing part axis.
13. bearing outer surface bearing outside surface
Rolling bearing outer ring or outer surface of the race.
14. Ferrule (washer) chamfer ring (washer) chamfer
The surface of the ferrule (gasket) where the inner bore or outer surface of the bearing is connected to one end of the ferrule.
15. Overpassing groove grinding undercut
In the ferrule or flange of the bearing ring or bearing washer, the groove or groove is opened for easy grinding.
16. Sealing (contact) surface sealing (conract) surface
The surface that is in sliding contact with the seal.
17. Seal (dust cover) groove seal(shield)groove
A groove for holding a bearing seal (dust cover).
18. Stop ring groove snap ring groove
a slot to hold the stop ring.
19. Lubrication groove
A groove for conveying lubricant on a bearing part.
20. lubrication hole
On the bearing part, a hole for conveying the lubricant to the rolling elements.
The rolling bearing bears the surface of the load portion and serves as a rolling track for the rolling elements.
2. Straight raceway straight raceway
The busbars in a plane perpendicular to the rolling direction are straight raceways.
3. Convex raceway crowned raceway
A substantially cylindrical {TodayHot} or conical raceway with a continuous micro-convex curve in a plane perpendicular to the rolling direction to prevent stress concentration at the roller-to-handle contact.
4. Spherical raceway
The raceway is part of the surface of the ball.
5. channel raceway groove
The ball bearing raceway is grooved, usually a circular arc-shaped cross section with a radius slightly larger than the radius of the ball.
6. (groove) shoulder
The side of the groove (rolling).
7. rib rib
A narrow shoulder that protrudes parallel to the rolling direction of the raceway surface. It is used to support and guide the rolling elements and keep them in the bearing.
8. Guide the surface of the cage
A cylindrical surface of the bearing ring and washer for guiding the cage in the radial direction.
9. Ferrule (gasket) end face ring (washer) face
A ferrule (washer) surface perpendicular to the ferrule (washer) axis.
10. Bearing bore bearing bore {HotTag}
The inner bore of the inner ring or shaft of the rolling bearing.
11. Cylindrical bore
The inner bore of a bearing or bearing part has a straight line that is substantially straight and parallel to the bearing shaft line or the bearing part axis.
12. Conical inner bore
The inner bore of a bearing or bearing part has a straight line that is substantially straight and intersects the bearing shaft line or the bearing part axis.
13. bearing outer surface bearing outside surface
Rolling bearing outer ring or outer surface of the race.
14. Ferrule (washer) chamfer ring (washer) chamfer
The surface of the ferrule (gasket) where the inner bore or outer surface of the bearing is connected to one end of the ferrule.
15. Overpassing groove grinding undercut
In the ferrule or flange of the bearing ring or bearing washer, the groove or groove is opened for easy grinding.
16. Sealing (contact) surface sealing (conract) surface
The surface that is in sliding contact with the seal.
17. Seal (dust cover) groove seal(shield)groove
A groove for holding a bearing seal (dust cover).
18. Stop ring groove snap ring groove
a slot to hold the stop ring.
19. Lubrication groove
A groove for conveying lubricant on a bearing part.
20. lubrication hole
On the bearing part, a hole for conveying the lubricant to the rolling elements.
Ceramic bearings and advantages
Ceramic bearing
Noun explanation: zirconia all ceramic bearing
All ceramic bearings are resistant to magnetic and electrical insulation, wear and corrosion resistance, oil-free self-lubricating, high temperature and high temperature resistance, and can be used in extremely harsh environments and special working conditions. The ferrule and rolling element are made of zirconia (ZrO2) ceramic material, and the retainer is made of polytetrafluoroethylene (PTFE) as standard. Generally, glass fiber reinforced nylon 66 (RPA66-25) and special engineering plastic (PEEK, PI), stainless steel (AISISUS316), brass (Cu), etc.
Silicon nitride full ceramic bearing
The silicon nitride all-ceramic bearing ring and rolling element are made of silicon nitride (Si3N4) ceramic material, and the retainer is made of polytetrafluoroethylene (PTFE) as standard. RPA66-25, PEEK, PI, and phenolic clip can also be used. Cloth bakelite pipes, etc. Compared to ZrO2, the SiN4 all-ceramic bearing is suitable for higher speed and load capacity, as well as for higher ambient temperatures. At the same time, it can provide precision ceramic bearings for high-speed, high-precision and high-rigidity spindles with the highest manufacturing precision up to P4 to UP.
Full ball full ceramic bearing
Full-ball type all-ceramic bearing with a ball gap on one side, because of the cage-free design, it can load more ceramic balls than the standard structure bearing, thus improving its load capacity, and avoiding the limitation of cage material. It can achieve the corrosion resistance and temperature resistance of ceramic cage type full ceramic bearings. This series of bearings is not suitable for high speed. When installing, please pay attention to the notch surface to the end that does not bear the axial load.
Ceramic cage full ceramic bearing
The ceramic cage has the advantages of wear resistance, high strength, corrosion resistance and self-lubrication. The all-ceramic bearing made of ceramic cage can be used in harsh environments such as extremely strong corrosion, ultra-high temperature and high vacuum. Common ceramic materials are ZrO2, Si3N4 or SiC
Mixed ceramic ball bearing
Ceramic balls, especially silicon nitride balls, have low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity. They are especially suitable for rolling elements of high speed, high precision and long life hybrid ceramic ball bearings (internal and external). The circle is metal). Generally, the inner and outer rings are made of bearing steel (GCr15) or stainless steel (AISI440C), and the ceramic balls can be made of ZrO2, Si3N4, or SiC.
Advantages of ceramic bearings
When it comes to ceramics, the first thing that comes to mind is the tableware commonly used in the home. With the development of technology, the physical properties of ceramics are applied to all walks of life including the bearing industry. Here are some of the advantages of ceramic bearings!
First, since ceramics are hardly corrosive, ceramic rolling bearings are suitable for operation under harsh conditions filled with corrosive media.
Second, since the density of the ceramic rolling ball is lower than that of the steel, the weight is much lighter, so the centrifugal effect of the outer ring can be reduced by 40% when rotating, and the service life is greatly extended.
Third, ceramics are less affected by thermal expansion and contraction than steel. Therefore, when the clearance of the bearing is constant, the bearing can be allowed to work in an environment where the temperature difference changes drastically.
Fourth, since the modulus of elasticity of ceramics is higher than that of steel, it is not easily deformed when subjected to force, so it is advantageous to increase the working speed and achieve higher precision. ?
In summary, due to the many advantages of ceramic bearings in the application, the major imported bearing manufacturers such as: SKF bearings, NSK bearings, FAG bearings are involved in this field and launched the corresponding products.
Advantages of ceramic bearings compared to all-steel bearings
Glossary:
In recent years, research and development of ceramic bearings at home and abroad have yielded fruitful results and substantial progress. It has been applied in machine tools, chemical industry, aerospace and other fields and has played a magical effect.
Ceramic bearings have the following magical advantages over all-steel bearings:
1, high speed and acceleration ability - can operate under the condition that the dn value exceeds 3 million, and the slip, wear and heat can be reduced;
2, long life, wear resistance - the fatigue life of all ceramic bearings is expected to be 10-50 times longer than all steel bearings, hybrid ceramic bearings, life is also 3-5 times higher than the life of all steel bearings;
3, the required lubrication is very small - the ceramic material has a low friction coefficient, using oil-lubricated ceramic bearings, in the case of lubricating oil is thin or lean, its lubricating ability is still not lower than the traditional lubricant commonly used in steel bearings;
4, wear-resistant - because the ceramic material is an inert material, it is more resistant to corrosion and wear;
5, the rigidity is large - due to the high modulus of elasticity of ceramic materials, its rigidity is 15-20% larger than ordinary steel bearings;
6, high temperature resistance - all ceramic bearings can work at temperatures above 500C;
7, low torque - according to the structure, the torque of ceramic bearings is reduced by about 1/3;
8, non-magnetic and non-conductive - ceramic bearings can be protected from magnetic and electrical damage.
With the deepening of research and breakthroughs in mass manufacturing technology, the application prospects of ceramic bearings in the fields of high speed, high temperature and corrosion resistance will be considerable.
Noun explanation: zirconia all ceramic bearing
All ceramic bearings are resistant to magnetic and electrical insulation, wear and corrosion resistance, oil-free self-lubricating, high temperature and high temperature resistance, and can be used in extremely harsh environments and special working conditions. The ferrule and rolling element are made of zirconia (ZrO2) ceramic material, and the retainer is made of polytetrafluoroethylene (PTFE) as standard. Generally, glass fiber reinforced nylon 66 (RPA66-25) and special engineering plastic (PEEK, PI), stainless steel (AISISUS316), brass (Cu), etc.
Silicon nitride full ceramic bearing
The silicon nitride all-ceramic bearing ring and rolling element are made of silicon nitride (Si3N4) ceramic material, and the retainer is made of polytetrafluoroethylene (PTFE) as standard. RPA66-25, PEEK, PI, and phenolic clip can also be used. Cloth bakelite pipes, etc. Compared to ZrO2, the SiN4 all-ceramic bearing is suitable for higher speed and load capacity, as well as for higher ambient temperatures. At the same time, it can provide precision ceramic bearings for high-speed, high-precision and high-rigidity spindles with the highest manufacturing precision up to P4 to UP.
Full ball full ceramic bearing
Full-ball type all-ceramic bearing with a ball gap on one side, because of the cage-free design, it can load more ceramic balls than the standard structure bearing, thus improving its load capacity, and avoiding the limitation of cage material. It can achieve the corrosion resistance and temperature resistance of ceramic cage type full ceramic bearings. This series of bearings is not suitable for high speed. When installing, please pay attention to the notch surface to the end that does not bear the axial load.
Ceramic cage full ceramic bearing
The ceramic cage has the advantages of wear resistance, high strength, corrosion resistance and self-lubrication. The all-ceramic bearing made of ceramic cage can be used in harsh environments such as extremely strong corrosion, ultra-high temperature and high vacuum. Common ceramic materials are ZrO2, Si3N4 or SiC
Mixed ceramic ball bearing
Ceramic balls, especially silicon nitride balls, have low density, high hardness, low friction coefficient, wear resistance, self-lubrication and good rigidity. They are especially suitable for rolling elements of high speed, high precision and long life hybrid ceramic ball bearings (internal and external). The circle is metal). Generally, the inner and outer rings are made of bearing steel (GCr15) or stainless steel (AISI440C), and the ceramic balls can be made of ZrO2, Si3N4, or SiC.
Advantages of ceramic bearings
When it comes to ceramics, the first thing that comes to mind is the tableware commonly used in the home. With the development of technology, the physical properties of ceramics are applied to all walks of life including the bearing industry. Here are some of the advantages of ceramic bearings!
First, since ceramics are hardly corrosive, ceramic rolling bearings are suitable for operation under harsh conditions filled with corrosive media.
Second, since the density of the ceramic rolling ball is lower than that of the steel, the weight is much lighter, so the centrifugal effect of the outer ring can be reduced by 40% when rotating, and the service life is greatly extended.
Third, ceramics are less affected by thermal expansion and contraction than steel. Therefore, when the clearance of the bearing is constant, the bearing can be allowed to work in an environment where the temperature difference changes drastically.
Fourth, since the modulus of elasticity of ceramics is higher than that of steel, it is not easily deformed when subjected to force, so it is advantageous to increase the working speed and achieve higher precision. ?
In summary, due to the many advantages of ceramic bearings in the application, the major imported bearing manufacturers such as: SKF bearings, NSK bearings, FAG bearings are involved in this field and launched the corresponding products.
Advantages of ceramic bearings compared to all-steel bearings
Glossary:
In recent years, research and development of ceramic bearings at home and abroad have yielded fruitful results and substantial progress. It has been applied in machine tools, chemical industry, aerospace and other fields and has played a magical effect.
Ceramic bearings have the following magical advantages over all-steel bearings:
1, high speed and acceleration ability - can operate under the condition that the dn value exceeds 3 million, and the slip, wear and heat can be reduced;
2, long life, wear resistance - the fatigue life of all ceramic bearings is expected to be 10-50 times longer than all steel bearings, hybrid ceramic bearings, life is also 3-5 times higher than the life of all steel bearings;
3, the required lubrication is very small - the ceramic material has a low friction coefficient, using oil-lubricated ceramic bearings, in the case of lubricating oil is thin or lean, its lubricating ability is still not lower than the traditional lubricant commonly used in steel bearings;
4, wear-resistant - because the ceramic material is an inert material, it is more resistant to corrosion and wear;
5, the rigidity is large - due to the high modulus of elasticity of ceramic materials, its rigidity is 15-20% larger than ordinary steel bearings;
6, high temperature resistance - all ceramic bearings can work at temperatures above 500C;
7, low torque - according to the structure, the torque of ceramic bearings is reduced by about 1/3;
8, non-magnetic and non-conductive - ceramic bearings can be protected from magnetic and electrical damage.
With the deepening of research and breakthroughs in mass manufacturing technology, the application prospects of ceramic bearings in the fields of high speed, high temperature and corrosion resistance will be considerable.
2018年12月7日星期五
FAG bearing material
The performance of rolling bearings is highly dependent on their material properties. FAG usually uses low-alloy, high-purity, integrally-hardened chrome steel as a material for the manufacture of bearing rings and rolling elements. For bearings bearing high impact loads and alternating bending stresses, carburized steel is used.
In recent years, FAG has been able to significantly increase the bearing capacity of its bearings due to the continuous improvement in the quality of bearing steels (of course, the price is also rising). Research results and practical experience have proven that today's standard rolling bearing steel bearings can achieve unlimited fatigue strength under good lubrication, clean environment and low load.
The heat treatment process of the FAG rolling bearing ring and the rolling element ensures that the bearing is within 150 degrees and the size is stable. For higher operating temperatures, special heat treatment methods are required. If the bearing is used in a corrosive environment, the bearing steel is required to be corrosive. Standard bearings made of stainless steel are prefixed with "S" and suffix "W203B".
This bearing is identical to the main dimensions and load carrying capacity of the overall hardened bearing steel bearing. In order to maintain its corrosion resistance, its surface cannot be damaged during installation and use. FAG produces silicon nitride balls for ceramic spindle bearings.
Ceramic balls are much lighter than steel balls, and centrifugal force and friction are also significantly smaller than steel balls. This type of bearing can still reach extremely high speeds during grease lubrication, and has a long service life and low operating temperature.
In recent years, FAG has been able to significantly increase the bearing capacity of its bearings due to the continuous improvement in the quality of bearing steels (of course, the price is also rising). Research results and practical experience have proven that today's standard rolling bearing steel bearings can achieve unlimited fatigue strength under good lubrication, clean environment and low load.
The heat treatment process of the FAG rolling bearing ring and the rolling element ensures that the bearing is within 150 degrees and the size is stable. For higher operating temperatures, special heat treatment methods are required. If the bearing is used in a corrosive environment, the bearing steel is required to be corrosive. Standard bearings made of stainless steel are prefixed with "S" and suffix "W203B".
This bearing is identical to the main dimensions and load carrying capacity of the overall hardened bearing steel bearing. In order to maintain its corrosion resistance, its surface cannot be damaged during installation and use. FAG produces silicon nitride balls for ceramic spindle bearings.
Ceramic balls are much lighter than steel balls, and centrifugal force and friction are also significantly smaller than steel balls. This type of bearing can still reach extremely high speeds during grease lubrication, and has a long service life and low operating temperature.
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