The friction mechanism of skf bearings is significantly different from other bearings. The friction is mainly determined by factors such as radial load, swing frequency, number of swings, swing angle, contact surface temperature and surface roughness. Generally, deep groove ball bearings produce friction when the inner and outer rings are relatively slid during movement, and the friction is large; while other bearings move, the friction between the pad layer and the inner ring or the outer ring is generated. Smaller. Studies have shown that under the same conditions, the friction coefficient of skf bearings of different materials has significant differences in the gasket material.
As the bearing continues to develop, its wear mechanism and form have also changed. During the working process, the generally lubricated bearings are caused by the relative sliding of the inner and outer rings, which causes the bearing working surface layer material to be continuously lost, resulting in the bearing not working properly. The main forms of wear are adhesive wear, abrasive wear and corrosion wear. The wear of deep groove ball bearings is due to the relative sliding of the gasket and the inner and outer rings during work, which causes the falling, tearing, extrusion and other failure modes of the gasket, resulting in the bearing not working properly.
The role of bearing lubrication can be briefly explained as follows:
a. Forming an oil film between the two rolling surfaces or sliding surfaces that contact each other to separate the two surfaces, reducing friction and wear on the contact surfaces.
b. When using oil lubrication, especially when using circulating oil lubrication, oil mist lubrication and fuel injection lubrication, the lubricating oil can take away most of the friction heat inside the deep groove ball bearing and play an effective heat dissipation effect.
c. When grease lubrication is used, foreign matter such as dust can be prevented from entering the bearing and sealing.
d. Lubricants have the effect of preventing metal corrosion.
e. Extend the fatigue life of the bearing.
As we all know, the work appearance always has a thousand points on the end of the deep groove ball bearing or the appropriate part of the shaft, even if the skf bearing parts are processed using the most advanced manufacturing technology. Observe how the reading changes with the preload load. The pre-tightening method has its disadvantages, such as increasing the friction torque of the imported bearings, increasing the temperature rise, shortening the life, etc., so it is necessary to comprehensively consider the small geometric errors of different levels, the roller bearings and the measurement of the clearance, the shaft Or the bearing housing needs to be rotated in different directions for several weeks to ensure proper contact between the ball end deep groove ball bearings and the leading edge on the inner ring.
The self-lubricating layer is continuously thinned, resulting in an increase in the wear depth of the skf bearing. It can be seen that the bearing failure is caused by the continuous extrusion of PTFE during the swinging process, the lubrication function is reduced, and finally the woven base material is worn.
2018年12月29日星期六
2018年12月18日星期二
Introduction to the classification of rolling bearings
A. Classified by rolling bearing structure type
(1) Bearings are classified according to their load direction or nominal contact angle:
1) Radial bearings - mainly used for rolling bearings bearing radial loads, with nominal contact angles from 0 to 45. According to the nominal contact angle, it is divided into: radial contact bearing----the radial bearing with the nominal contact angle of 0: the radial angular contact bearing---the radial bearing with the nominal contact angle greater than 0 to 45.
2) Thrust bearings - mainly used for rolling bearings bearing axial loads, with a nominal contact angle greater than 45 to 90. According to the nominal contact angle, it is divided into: axial contact bearing----the thrust bearing with the nominal contact angle of 90: thrust angular contact bearing----the thrust bearing with the nominal contact angle greater than 45 but less than 90.
(2) Bearings are classified according to the type of rolling elements:
1) Ball bearing----rolling body is the ball:
2) Roller bearing----The rolling element is a roller. Roller bearings are divided into: roller bearings----rolling elements are cylindrical roller bearings. The ratio of length to diameter of cylindrical rollers is less than or equal to 3; needle roller bearings---- The rolling element is a needle roller bearing, the ratio of the length to the diameter of the needle roller is greater than 3, but the diameter is less than or equal to 5 mm; the tapered roller bearing----the rolling element is the bearing of the tapered roller; the spherical roller bearing one by one The rolling elements are bearings of spherical rollers.
(3) Whether the bearing can be adjusted according to its work, is divided into:
1) Self-aligning bearing----The raceway is spherical, which can adapt to the angular deviation and angular movement between the two raceways.
2) Non-aligning bearings (rigid bearings)----bearings that can offset the axial angle between the raceways.
(4) The bearing is divided into: according to the number of rows of rolling elements:
1) Single row bearings - bearings with a row of rolling elements.
2) Double row bearings - bearings with two rows of rolling elements.
3) Multi-row bearings----bearings with more than two rows of rolling elements, such as three-row and four-row bearings.
(5) Bearings can be separated according to their components, and are divided into:
1) separable bearings---bearings with separable parts;
2) Non-separable bearings----bearings that cannot be freely separated after the final assembly.
(6) Bearings can be divided into various structural types according to their structural shape (if there is no filling groove, whether there are inner and outer rings and the shape of the ferrule, the structure of the rib, or even the cage).
B. According to the size of the rolling bearing, the bearing is divided into: according to its outer diameter size:
(1) Miniature bearings----bearings with a nominal outside diameter range of 26 mm or less.
(2) Small bearings----bearings with a nominal outer diameter range of 28-55mm.
(3) Small and medium-sized bearings----bearings with a nominal outer diameter range of 60-115mm.
(4) Medium and large-sized bearings----bearings with a nominal outer diameter range of 120-190mm.
(5) Large bearings----bearings with a nominal outer diameter range of 200-430mm.
(6) Extra large bearings----bearings with a nominal outer diameter range of 440mm or more.
(1) Bearings are classified according to their load direction or nominal contact angle:
1) Radial bearings - mainly used for rolling bearings bearing radial loads, with nominal contact angles from 0 to 45. According to the nominal contact angle, it is divided into: radial contact bearing----the radial bearing with the nominal contact angle of 0: the radial angular contact bearing---the radial bearing with the nominal contact angle greater than 0 to 45.
2) Thrust bearings - mainly used for rolling bearings bearing axial loads, with a nominal contact angle greater than 45 to 90. According to the nominal contact angle, it is divided into: axial contact bearing----the thrust bearing with the nominal contact angle of 90: thrust angular contact bearing----the thrust bearing with the nominal contact angle greater than 45 but less than 90.
(2) Bearings are classified according to the type of rolling elements:
1) Ball bearing----rolling body is the ball:
2) Roller bearing----The rolling element is a roller. Roller bearings are divided into: roller bearings----rolling elements are cylindrical roller bearings. The ratio of length to diameter of cylindrical rollers is less than or equal to 3; needle roller bearings---- The rolling element is a needle roller bearing, the ratio of the length to the diameter of the needle roller is greater than 3, but the diameter is less than or equal to 5 mm; the tapered roller bearing----the rolling element is the bearing of the tapered roller; the spherical roller bearing one by one The rolling elements are bearings of spherical rollers.
(3) Whether the bearing can be adjusted according to its work, is divided into:
1) Self-aligning bearing----The raceway is spherical, which can adapt to the angular deviation and angular movement between the two raceways.
2) Non-aligning bearings (rigid bearings)----bearings that can offset the axial angle between the raceways.
(4) The bearing is divided into: according to the number of rows of rolling elements:
1) Single row bearings - bearings with a row of rolling elements.
2) Double row bearings - bearings with two rows of rolling elements.
3) Multi-row bearings----bearings with more than two rows of rolling elements, such as three-row and four-row bearings.
(5) Bearings can be separated according to their components, and are divided into:
1) separable bearings---bearings with separable parts;
2) Non-separable bearings----bearings that cannot be freely separated after the final assembly.
(6) Bearings can be divided into various structural types according to their structural shape (if there is no filling groove, whether there are inner and outer rings and the shape of the ferrule, the structure of the rib, or even the cage).
B. According to the size of the rolling bearing, the bearing is divided into: according to its outer diameter size:
(1) Miniature bearings----bearings with a nominal outside diameter range of 26 mm or less.
(2) Small bearings----bearings with a nominal outer diameter range of 28-55mm.
(3) Small and medium-sized bearings----bearings with a nominal outer diameter range of 60-115mm.
(4) Medium and large-sized bearings----bearings with a nominal outer diameter range of 120-190mm.
(5) Large bearings----bearings with a nominal outer diameter range of 200-430mm.
(6) Extra large bearings----bearings with a nominal outer diameter range of 440mm or more.
2018年12月14日星期五
Bearing housing
1) Determination of the manufacturing process
Casting mechanism and analysis of its casting process, the bearing housing is used to clamp the bearing, thus supporting the shaft and the parts on the shaft.
The weight of the casting is about 10Kg
Parts material is HT200
Outline size (215X80X146)mm
Production program: mass production
2) Due to the small casting, it is advisable to use a veil and a wet type with a back yarn.
3) Modeling method: whole mold, live block, two-box model
4) Determination of the parting surface
The whole shape of the bearing seat is divided into sections, and wood is used as the sand core of Φ62.5, and basically all are in one plane. Therefore, the entire shape of the bearing is selected as the parting surface, so that the entire cavity is in the down shape, so that The type is also easy to safely pour the riser.
5) Determination of the location of the riser
The casting part is HT200, the volume shrinkage rate is small, but the casting part is a thick solid part, so attention should be paid to the occurrence of shrinkage hole defects, so the position and direction of the introduction of the inner runner is very important, according to the structural characteristics of the casting, the orientation is adopted. The principle of solidification, the inner runner should be introduced from both ends of the base, so as to prevent the sand type of Φ62.5 from being damaged, and the contact hot runner can be reduced by pressing the gate of the press edge, that is, the contact hot section of the gate and the casting can be reduced. Moreover, the overheating of the thick portion in the middle can be avoided, and the solidification time can be shortened, which is advantageous for obtaining qualified castings. In addition, since the crimping gate has a good feeding effect, the casting member does not need to be provided with a feeding riser to prevent the generation of the pores. An venting position of Φ8-Φ10mm can be set at the position of the top middle edge.
Casting mechanism and analysis of its casting process, the bearing housing is used to clamp the bearing, thus supporting the shaft and the parts on the shaft.
The weight of the casting is about 10Kg
Parts material is HT200
Outline size (215X80X146)mm
Production program: mass production
2) Due to the small casting, it is advisable to use a veil and a wet type with a back yarn.
3) Modeling method: whole mold, live block, two-box model
4) Determination of the parting surface
The whole shape of the bearing seat is divided into sections, and wood is used as the sand core of Φ62.5, and basically all are in one plane. Therefore, the entire shape of the bearing is selected as the parting surface, so that the entire cavity is in the down shape, so that The type is also easy to safely pour the riser.
5) Determination of the location of the riser
The casting part is HT200, the volume shrinkage rate is small, but the casting part is a thick solid part, so attention should be paid to the occurrence of shrinkage hole defects, so the position and direction of the introduction of the inner runner is very important, according to the structural characteristics of the casting, the orientation is adopted. The principle of solidification, the inner runner should be introduced from both ends of the base, so as to prevent the sand type of Φ62.5 from being damaged, and the contact hot runner can be reduced by pressing the gate of the press edge, that is, the contact hot section of the gate and the casting can be reduced. Moreover, the overheating of the thick portion in the middle can be avoided, and the solidification time can be shortened, which is advantageous for obtaining qualified castings. In addition, since the crimping gate has a good feeding effect, the casting member does not need to be provided with a feeding riser to prevent the generation of the pores. An venting position of Φ8-Φ10mm can be set at the position of the top middle edge.
2018年12月12日星期三
Aspects of the main impact of KOYO bearing installation on life
There are many factors that determine the length of the bearing life, but it can be roughly divided into two types, one is the internal factor (the factor of KOYO bearing itself), and the other is the external factor of the bearing.
The internal factors of the bearing mainly include three factors: structural design, manufacturing process and material quality.
Bearings are generally manufactured through multiple processes such as forging, heat treatment, turning, grinding and assembly. However, the rationality, advancement and stability of each processing technology will also affect the life of the bearing. The heat treatment and grinding processes that affect the quality of the finished KOYO bearing usually have a more direct relationship with the failure of the bearing.
The metallurgical quality of KOYO bearing materials was the main factor affecting the early failure of rolling bearings. With the advancement of metallurgical techniques (such as vacuum degassing of bearing steels), the quality of raw materials has improved. The proportion of raw material quality factors in bearing failure analysis has dropped significantly, but it is still one of the main factors affecting bearing failure. The proper selection of materials is still a factor that must be considered in bearing failure analysis.
(1) The condition of adopting a small interference fit to the fixing ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it is difficult to install and it is difficult to disassemble. In addition, the influence of the spindle thermal elongation needs to be considered. .
(2) The main shaft of the paired double-angle contact ball bearing is lighter, and if the interference is too large, the axial pre-tightening amount will be significantly larger, which will cause adverse effects. The main shaft of the double-row short bearing and the main shaft of the bearing have a relatively large load, so the interference between them is relatively large.
(3) The roundness of the shaft and the seat hole and the perpendicularity of the shoulder should be required according to the corresponding accuracy of the KOYO bearing.
(4) It is necessary to accurately calculate the interference of the rotating ferrule, and accurately calculate the appropriate amount of the fixed ferrule.
The amount of interference of the rotating ferrule should also be smaller within the possible range. As long as the thermal expansion effect at the working temperature and the centrifugal force at the highest speed are effectively ensured, the creeping or sliding of the tight fitting surface is not caused. The fixed ferrule is selected according to the working load size and KOYO bearing size, and a small clearance fit or interference fit is selected. Too loose or too tight is not conducive to maintaining the original precise shape.
(5) If the KOYO bearing is running under high speed conditions and the working temperature is high, special attention should be paid to the fact that the rotation of the rotating ferrule should not be too loose to prevent eccentric vibration, and the fit of the fixed ferrule should not occur to prevent the ferrule. Deformation under load and vibration
The internal factors of the bearing mainly include three factors: structural design, manufacturing process and material quality.
Bearings are generally manufactured through multiple processes such as forging, heat treatment, turning, grinding and assembly. However, the rationality, advancement and stability of each processing technology will also affect the life of the bearing. The heat treatment and grinding processes that affect the quality of the finished KOYO bearing usually have a more direct relationship with the failure of the bearing.
The metallurgical quality of KOYO bearing materials was the main factor affecting the early failure of rolling bearings. With the advancement of metallurgical techniques (such as vacuum degassing of bearing steels), the quality of raw materials has improved. The proportion of raw material quality factors in bearing failure analysis has dropped significantly, but it is still one of the main factors affecting bearing failure. The proper selection of materials is still a factor that must be considered in bearing failure analysis.
(1) The condition of adopting a small interference fit to the fixing ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it is difficult to install and it is difficult to disassemble. In addition, the influence of the spindle thermal elongation needs to be considered. .
(2) The main shaft of the paired double-angle contact ball bearing is lighter, and if the interference is too large, the axial pre-tightening amount will be significantly larger, which will cause adverse effects. The main shaft of the double-row short bearing and the main shaft of the bearing have a relatively large load, so the interference between them is relatively large.
(3) The roundness of the shaft and the seat hole and the perpendicularity of the shoulder should be required according to the corresponding accuracy of the KOYO bearing.
(4) It is necessary to accurately calculate the interference of the rotating ferrule, and accurately calculate the appropriate amount of the fixed ferrule.
The amount of interference of the rotating ferrule should also be smaller within the possible range. As long as the thermal expansion effect at the working temperature and the centrifugal force at the highest speed are effectively ensured, the creeping or sliding of the tight fitting surface is not caused. The fixed ferrule is selected according to the working load size and KOYO bearing size, and a small clearance fit or interference fit is selected. Too loose or too tight is not conducive to maintaining the original precise shape.
(5) If the KOYO bearing is running under high speed conditions and the working temperature is high, special attention should be paid to the fact that the rotation of the rotating ferrule should not be too loose to prevent eccentric vibration, and the fit of the fixed ferrule should not occur to prevent the ferrule. Deformation under load and vibration
2018年12月8日星期六
Bearing steel quality requirements and defects
1. Quality requirements for bearing steel. Rolling bearings should work at high speed and for a long time under complex stress states such as tensile, compression, bending, shearing, alternating, and high stress values. Therefore, in the production process, there are many quality control inspection items for bearing steel, and the control scope is narrow. The production process is strict and complicated. It requires certain tooling equipment, inspection methods and a certain level of villain technology. In order to ensure good bearing performance and high life, the quality requirements for bearing steel are as follows:
(1) Chemical composition: Chemical composition is the most essential factor of bearing steel. The physical, chemical, mechanical properties and metallographic structure of steel are determined by chemical composition. Changing the chemical composition changes the basic properties of steel. Therefore, the chemical composition of the bearing steel must meet the allowable range of the standard.
(2) Internal quality: can be divided into macro quality and micro quality.
Macro quality: It is required that there are no defects such as white spots, shrinkage holes, slag inclusions, civilian metals, cracks, over-burning, and subcutaneous bubbles in the bearing steel. Internal segregation and loose control of the bearing steel are required to be within a certain range. In short, the inside of the bearing steel is dense, and it is not allowed to have a visible defect to cut the base of the steel.
Microscopic quality: It is required that the internal structure of the bearing steel should be uniform and the purity should be high.
The internal structure of the bearing steel refers to a carbide ribbon, a carbide network, a carbide liquid deposition, and an annealed structure. Carbide is one of the main components of bearing steel, and it exists objectively. How to make the distribution of carbides uniform, scattered and small is one of the important topics to improve the quality of bearing steel. In recent years, major manufacturers of bearing steel have adopted high-temperature diffusion treatment, controlled rolling new technology and continuous annealing furnace equipment. Even so, the distribution of carbides is still not as good. Therefore, in the standard, their allowable range and control level are specified.
The purity of the bearing steel refers to the degree of contamination of the steel by non-metallic inclusions. Non-metallic inclusions are the kind of material of the bearing steel matrix, which destroys the continuity of the matrix and is one of the main causes of early fatigue and spalling of the bearing. Therefore, it is required that the amount of non-metallic inclusions in the bearing steel is as small as possible. In order to limit and control the presence of non-metallic inclusions in steel, they are strictly controlled in the standard. In addition to electric furnace smelting and electric slag remelting, the manufacturer also adopts electric furnace smelting and refining, vacuum deoxidation, argon blowing treatment, and furnace powder spraying treatment, in an effort to reduce the oxygen content in the steel to less than 20 ppm.
(3) Surface quality: The forming method of bearing parts, currently forging, turning and cold punching. According to different molding methods, there are different requirements for the surface quality of steel. In general, the bearing steel surface must not have cracks, folds, cracks, crusting and slag inclusions. For the cold drawn steel used for cold punching, in addition to the above defects, the surface should be clean and free of defects such as rust and burrs. There must be no serious decarburization on the surface of the bearing steel. According to the different requirements of the molding process of the bearing parts, in the standard, there are different restrictions on the depth of the decarburization layer of different types of steel.
(4) Dimensional allowable tolerance: According to the molding process of the bearing parts and the production process of steel, the dimensional tolerances of various varieties and specifications of the bearing steel are specified in the standard. The dimensional tolerance of forged steel is generally in accordance with GB908-72 standard, the dimensional tolerance of hot rolled steel is according to GB702-86, the cold drawn steel is according to GB905-82 standard, and the cold drawn steel wire is according to YB245-64 standard.
(1) Chemical composition: Chemical composition is the most essential factor of bearing steel. The physical, chemical, mechanical properties and metallographic structure of steel are determined by chemical composition. Changing the chemical composition changes the basic properties of steel. Therefore, the chemical composition of the bearing steel must meet the allowable range of the standard.
(2) Internal quality: can be divided into macro quality and micro quality.
Macro quality: It is required that there are no defects such as white spots, shrinkage holes, slag inclusions, civilian metals, cracks, over-burning, and subcutaneous bubbles in the bearing steel. Internal segregation and loose control of the bearing steel are required to be within a certain range. In short, the inside of the bearing steel is dense, and it is not allowed to have a visible defect to cut the base of the steel.
Microscopic quality: It is required that the internal structure of the bearing steel should be uniform and the purity should be high.
The internal structure of the bearing steel refers to a carbide ribbon, a carbide network, a carbide liquid deposition, and an annealed structure. Carbide is one of the main components of bearing steel, and it exists objectively. How to make the distribution of carbides uniform, scattered and small is one of the important topics to improve the quality of bearing steel. In recent years, major manufacturers of bearing steel have adopted high-temperature diffusion treatment, controlled rolling new technology and continuous annealing furnace equipment. Even so, the distribution of carbides is still not as good. Therefore, in the standard, their allowable range and control level are specified.
The purity of the bearing steel refers to the degree of contamination of the steel by non-metallic inclusions. Non-metallic inclusions are the kind of material of the bearing steel matrix, which destroys the continuity of the matrix and is one of the main causes of early fatigue and spalling of the bearing. Therefore, it is required that the amount of non-metallic inclusions in the bearing steel is as small as possible. In order to limit and control the presence of non-metallic inclusions in steel, they are strictly controlled in the standard. In addition to electric furnace smelting and electric slag remelting, the manufacturer also adopts electric furnace smelting and refining, vacuum deoxidation, argon blowing treatment, and furnace powder spraying treatment, in an effort to reduce the oxygen content in the steel to less than 20 ppm.
(3) Surface quality: The forming method of bearing parts, currently forging, turning and cold punching. According to different molding methods, there are different requirements for the surface quality of steel. In general, the bearing steel surface must not have cracks, folds, cracks, crusting and slag inclusions. For the cold drawn steel used for cold punching, in addition to the above defects, the surface should be clean and free of defects such as rust and burrs. There must be no serious decarburization on the surface of the bearing steel. According to the different requirements of the molding process of the bearing parts, in the standard, there are different restrictions on the depth of the decarburization layer of different types of steel.
(4) Dimensional allowable tolerance: According to the molding process of the bearing parts and the production process of steel, the dimensional tolerances of various varieties and specifications of the bearing steel are specified in the standard. The dimensional tolerance of forged steel is generally in accordance with GB908-72 standard, the dimensional tolerance of hot rolled steel is according to GB702-86, the cold drawn steel is according to GB905-82 standard, and the cold drawn steel wire is according to YB245-64 standard.
Linear bearing series introduction
Linear bearings are linear motion systems that are produced at low cost and are used with infinite strokes in conjunction with cylindrical shafts. Since the carrier ball is in point contact with the shaft, the load is small. The steel ball rotates with a very small frictional resistance, so that smooth motion with high precision can be obtained.
Linear bearings are widely used in precision equipment such as electronic equipment, tensile testing machines and digital three-dimensional coordinate measuring equipment, as well as sliding of industrial machinery such as multi-axis machine tools, punching machines, tool grinding machines, automatic gas cutting machines, printers, card sorting machines, food packaging machines, etc. component.
Lubrication and friction
Grease lubrication
Inject the anti-corrosion oil into the linear bearing. If it is lubricated with grease, first remove the anti-corrosion oil with kerosene or organic solvent, and add the grease after air drying.
It is recommended to use a lithium soap grease with a tack of N0.2.
Oil lubrication
If lubricating with oil, it is not necessary to remove the anti-corrosion oil. According to the temperature change, the lubricating oil of ISO viscosity grade VG15-100 can be used. The shaft lubrication can be given from the oil supply pipe or from the oil hole on the outer bearing housing. Since the seal will scrape off the oil, oil lubrication is not applicable to the non-porous seal bearing.
Linear guide bearings:
A slot or ridge made of metal or other material that can withstand, secure, or guide a moving device or device and reduce its friction. Longitudinal grooves or ridges on the surface of the rail for guiding, securing machine parts, special equipment, instruments, etc.
Rails are also common in our daily lives, such as the sliding door sliding door, the train's rails, etc. are the specific application of the guide rail.
Linear bearings are widely used in precision equipment such as electronic equipment, tensile testing machines and digital three-dimensional coordinate measuring equipment, as well as sliding of industrial machinery such as multi-axis machine tools, punching machines, tool grinding machines, automatic gas cutting machines, printers, card sorting machines, food packaging machines, etc. component.
Lubrication and friction
Grease lubrication
Inject the anti-corrosion oil into the linear bearing. If it is lubricated with grease, first remove the anti-corrosion oil with kerosene or organic solvent, and add the grease after air drying.
It is recommended to use a lithium soap grease with a tack of N0.2.
Oil lubrication
If lubricating with oil, it is not necessary to remove the anti-corrosion oil. According to the temperature change, the lubricating oil of ISO viscosity grade VG15-100 can be used. The shaft lubrication can be given from the oil supply pipe or from the oil hole on the outer bearing housing. Since the seal will scrape off the oil, oil lubrication is not applicable to the non-porous seal bearing.
Linear guide bearings:
A slot or ridge made of metal or other material that can withstand, secure, or guide a moving device or device and reduce its friction. Longitudinal grooves or ridges on the surface of the rail for guiding, securing machine parts, special equipment, instruments, etc.
Rails are also common in our daily lives, such as the sliding door sliding door, the train's rails, etc. are the specific application of the guide rail.
2018年12月7日星期五
Research on Factors Affecting Friction Coefficient of High Performance Plastic Bearings
High-performance plastic bearings are often processed from self-lubricating modified engineering plastics. The friction coefficient of plastic bearings directly affects the service life of the bearings and the required driving force, and directly leads to the working temperature of the equipment. Therefore, the friction coefficient of the bearing is a performance parameter that the bearing design engineer pays close attention to.
The friction coefficient of self-lubricating plastic bearings depends to a large extent on the self-lubricating properties of the materials used in the bearings. China CSB Company also found that in addition to the plastic bearing materials themselves, the working friction coefficient of plastic bearings has also received numerous The influence of external factors, such as working load, speed of movement, ambient temperature, etc., CSB engineers in the tens of thousands of laboratory tests have concluded that the friction coefficient of self-lubricating plastic bearings decreases with increasing working load; It increases with the increase of the speed of movement; it increases with the increase of the working temperature.
CSB engineers found in the test that the plastic bearings CSB-EP and CSB-EP13 have a lower friction coefficient below 80 °C, the new plastic bearing CSB-EP3 and the new material CSB-EP3G have lower friction at 130 °C. The coefficient, while the high-performance plastic bearings CSB-EP5 and CSB-EP5Z have an extremely low coefficient of friction of about 0.11 despite high load and 160 temperatures.
In addition, CSB research engineers also found that the friction coefficient of self-lubricating plastic bearings is also affected by the surface finish of the grinding shaft. It is found that the lower or higher the smoothness of the shaft leads to an increase in the friction coefficient, and the shaft finish is ideally in Ra0. 4 to 0.8, which has a lower coefficient of friction.
The friction coefficient of self-lubricating plastic bearings depends to a large extent on the self-lubricating properties of the materials used in the bearings. China CSB Company also found that in addition to the plastic bearing materials themselves, the working friction coefficient of plastic bearings has also received numerous The influence of external factors, such as working load, speed of movement, ambient temperature, etc., CSB engineers in the tens of thousands of laboratory tests have concluded that the friction coefficient of self-lubricating plastic bearings decreases with increasing working load; It increases with the increase of the speed of movement; it increases with the increase of the working temperature.
CSB engineers found in the test that the plastic bearings CSB-EP and CSB-EP13 have a lower friction coefficient below 80 °C, the new plastic bearing CSB-EP3 and the new material CSB-EP3G have lower friction at 130 °C. The coefficient, while the high-performance plastic bearings CSB-EP5 and CSB-EP5Z have an extremely low coefficient of friction of about 0.11 despite high load and 160 temperatures.
In addition, CSB research engineers also found that the friction coefficient of self-lubricating plastic bearings is also affected by the surface finish of the grinding shaft. It is found that the lower or higher the smoothness of the shaft leads to an increase in the friction coefficient, and the shaft finish is ideally in Ra0. 4 to 0.8, which has a lower coefficient of friction.
2018年12月5日星期三
How to ensure reliable bearing work
Generally speaking, pay attention to the following points from the perspective of use:
1. The bearing clearance should be appropriate, and the impact will be too large. If it is too small, the lubrication will be poor and the tile may be burnt.
2. Bearing and journal surface quality and geometry should be strictly guaranteed.
3. Improve lubrication quality, control oil pressure, temperature and flow, and strengthen oil filtration.
4. Controlling the temperature state of the diesel engine is unfavorable in the event of overcooling and overheating. In cold weather, the diesel engine should be preheated before starting, and the crankshaft should be turned by hand to make the oil enter the friction surface.
5. Use qualified fuel and lubricants.
1. The bearing clearance should be appropriate, and the impact will be too large. If it is too small, the lubrication will be poor and the tile may be burnt.
2. Bearing and journal surface quality and geometry should be strictly guaranteed.
3. Improve lubrication quality, control oil pressure, temperature and flow, and strengthen oil filtration.
4. Controlling the temperature state of the diesel engine is unfavorable in the event of overcooling and overheating. In cold weather, the diesel engine should be preheated before starting, and the crankshaft should be turned by hand to make the oil enter the friction surface.
5. Use qualified fuel and lubricants.
Sheet-fed main roller support bearing technology
Due to its superior structure, sheetfed offset presses are increasingly becoming the main products of printing machinery, and the requirements for printing quality are constantly improving. Domestic offset press manufacturers have also developed from the production of original monochrome and two-color machines to four-color machines and multi-color machines. Each color set of a sheetfed offset press consists primarily of a plate cylinder, a blanket cylinder, a pressure roller, a transfer cylinder, and other ink and accessory systems. The running accuracy of the main drum directly affects the quality of the printing, and there is no direct relationship between whether the overprinting, the netting and the coloring will occur. Domestic and foreign well-known printing machine manufacturers have higher and higher requirements for the running accuracy of the main drum. Bearings that support the main drum play a vital role. In order to improve the quality of the printer and increase the added value, many printer manufacturers have to increase the bearing requirements at all costs.
With the history of sheetfed offset presses, the main roller bearings have undergone many changes. From the previous brass plain bearings to roller bearings, from needle bearings to roller bearings, from single bearings to combined bearings, from two-ring bearings to three-ring eccentric bearings. The accuracy of the roller bearing is getting higher and higher, the installation is more convenient, and the maintenance is more and more simple.
One. Needle bearing
The rigidity of the needle bearing is much better than that of the tapered roller bearing because of its small roller diameter, and the double-column needle roller bearing developed by the bearing company makes the rigidity comparable to that of the copper sleeve sliding bearing. Compared with ordinary needle bearings, the needle roller grouping of the needle roller bearings used for the printing machine drum support is higher than ordinary. The needle roller grouping of a conventional needle bearing is in units of 2 μm, and the needle roller grouping used in the printing machine is in units of 1 μm. In this way, by selecting the appropriate needle grouping, the working clearance of the bearing can be less than 1 μm, which is required for high-quality printing machines. And the needle roller grouping used by the printing machine can be more than the grouping group of the ordinary needle bearing, so that the processing requirements for the wallboard can be naturally reduced.
Two. Roller bearing
The use of needle bearings still makes printer manufacturers annoyed with the need for high-precision jackets and the need for experienced installers to find the right needle roller group. In order to solve this problem, the bearing manufacturer developed a roller bearing support with an outer ring integrated flange. Roller bearings can be pre-tensioned for good precision and rigidity. A tapered inner ring can also be used to arbitrarily adjust the bearing working clearance. This solution fully meets the need for zero clearance of the printer roller bearings. Moreover, the flanged outer ring solves the problem of installation and lubrication for the printer manufacturer. This bearing is widely used in Manroland, Heidelberg, Japan's Liby, and domestic Beiren models. Its roller bearing support scheme has become the mainstream solution for roller support in printing presses.
three. Integrated unit
Like the automotive industry and other industries, printer manufacturers need precision-product suppliers like bearings to provide simpler modular components to reduce factory assembly errors and time, and reduce rework rates, thereby increasing efficiency and reducing costs. In order to meet this demand, bearing manufacturers provide roller support units with higher precision and easier installation and maintenance. Such as the three-ring eccentric bearing unit developed by the bearing company. The bearing unit integrates the bearing and the eccentric sleeve, and not only has the function of supporting the roller, but also realizes the function of the roller clutch pressure and registration. Its superiority has been widely accepted by printer manufacturers.
KBA, Manroland's models and Heidelberg's new models have already used this bearing unit on plate or blanket cylinders. In the modification of the old model, this three-ring bearing support has become the first choice. There is currently no better solution for performance, installation, and maintenance than this bearing unit. The use of labyrinth seals and cylindrical rollers allows them to be oil lubricated, grease lubricated and maintenance free for life. Excellent lubrication also makes the life of this bearing the longest in any solution. It has enabled printer manufacturers to move from their own processing and installation lines to their own production lines for precision products such as bearings. This is also in line with the intensification of modern industry. The above are various solutions for the main drum support of the printing machine. Due to its own precision requirements, the printing machine has high requirements for the support of rotating and linear moving parts. The above solutions can completely solve the needs of domestic printer manufacturers to develop their own more distinctive products.
With the history of sheetfed offset presses, the main roller bearings have undergone many changes. From the previous brass plain bearings to roller bearings, from needle bearings to roller bearings, from single bearings to combined bearings, from two-ring bearings to three-ring eccentric bearings. The accuracy of the roller bearing is getting higher and higher, the installation is more convenient, and the maintenance is more and more simple.
One. Needle bearing
The rigidity of the needle bearing is much better than that of the tapered roller bearing because of its small roller diameter, and the double-column needle roller bearing developed by the bearing company makes the rigidity comparable to that of the copper sleeve sliding bearing. Compared with ordinary needle bearings, the needle roller grouping of the needle roller bearings used for the printing machine drum support is higher than ordinary. The needle roller grouping of a conventional needle bearing is in units of 2 μm, and the needle roller grouping used in the printing machine is in units of 1 μm. In this way, by selecting the appropriate needle grouping, the working clearance of the bearing can be less than 1 μm, which is required for high-quality printing machines. And the needle roller grouping used by the printing machine can be more than the grouping group of the ordinary needle bearing, so that the processing requirements for the wallboard can be naturally reduced.
Two. Roller bearing
The use of needle bearings still makes printer manufacturers annoyed with the need for high-precision jackets and the need for experienced installers to find the right needle roller group. In order to solve this problem, the bearing manufacturer developed a roller bearing support with an outer ring integrated flange. Roller bearings can be pre-tensioned for good precision and rigidity. A tapered inner ring can also be used to arbitrarily adjust the bearing working clearance. This solution fully meets the need for zero clearance of the printer roller bearings. Moreover, the flanged outer ring solves the problem of installation and lubrication for the printer manufacturer. This bearing is widely used in Manroland, Heidelberg, Japan's Liby, and domestic Beiren models. Its roller bearing support scheme has become the mainstream solution for roller support in printing presses.
three. Integrated unit
Like the automotive industry and other industries, printer manufacturers need precision-product suppliers like bearings to provide simpler modular components to reduce factory assembly errors and time, and reduce rework rates, thereby increasing efficiency and reducing costs. In order to meet this demand, bearing manufacturers provide roller support units with higher precision and easier installation and maintenance. Such as the three-ring eccentric bearing unit developed by the bearing company. The bearing unit integrates the bearing and the eccentric sleeve, and not only has the function of supporting the roller, but also realizes the function of the roller clutch pressure and registration. Its superiority has been widely accepted by printer manufacturers.
KBA, Manroland's models and Heidelberg's new models have already used this bearing unit on plate or blanket cylinders. In the modification of the old model, this three-ring bearing support has become the first choice. There is currently no better solution for performance, installation, and maintenance than this bearing unit. The use of labyrinth seals and cylindrical rollers allows them to be oil lubricated, grease lubricated and maintenance free for life. Excellent lubrication also makes the life of this bearing the longest in any solution. It has enabled printer manufacturers to move from their own processing and installation lines to their own production lines for precision products such as bearings. This is also in line with the intensification of modern industry. The above are various solutions for the main drum support of the printing machine. Due to its own precision requirements, the printing machine has high requirements for the support of rotating and linear moving parts. The above solutions can completely solve the needs of domestic printer manufacturers to develop their own more distinctive products.
2018年12月4日星期二
Self lubricating bearing
The plastic layer on the surface of the self-lubricating bearing can be kept in a sufficient margin during processing, and the device can be processed by itself after being pressed into the seat hole to achieve a better installation size. What is the relationship between the use of self-lubricating bearings and the sliding bearing? When we choose self-lubricating bearings, we must first watch the three objectives of the joints. One, hardness and hardness are one of the key guidelines for the quality of the bearing. It has an indirect effect on the self-lubricating bearing for fatigue strength, wear resistance and elastic limit. The hardness of the self-lubricating bearing under the condition of use should reach HRC61-65 individually. The higher hardness can make the bearing achieve higher contact fatigue strength and wear resistance.
Solid inlaid self-lubricating bearing introduction:
Metal-based inlaid solid self-lubricating bearing (referred to as jdb) is a novel lubricated bearing that combines the characteristics of metal bearing and the characteristics of self-lubricating bearing. The metal matrix bears the load, and the specially formulated solid lubricating material acts as a lubrication.
It has the characteristics of high bearing capacity, impact resistance, high temperature resistance and strong self-lubricating ability. It is especially suitable for heavy load, low speed, reciprocating or swinging, etc., which is difficult to lubricate and form oil film. It is also not afraid of water and other acid etching. And scouring. The cleaning of the removed bearings is divided into coarse cleaning and fine cleaning. They are placed in the container respectively, and the metal mesh bottom is placed first so that the bearing does not directly contact the container. When rough cleaning, if the bearing is rotated with dirt, it will damage the rolling surface of the bearing and should be noted. In the rough cleaning oil, use a brush to remove the grease and the adhesive. After it is almost clean, it is transferred to the fine wash. Fine washing is to carefully clean the bearing while rotating it in the cleaning oil. In addition, the cleaning oil should always be kept clean. The majority of users generally reflect that the inlaid bearing is not only fuel-efficient, energy-saving, but also has a longer working life than ordinary sliding bearings. The use of self-lubricating bearings has been widely used in metallurgical continuous casting machines, rolling equipment, mining machinery, ships, steam turbines, hydraulic turbines, injection molding machines and equipment production lines.
Most of the bearings use SUJ2 in JIS steel. Large bearings use SUJ3. The chemical composition of SUJ2 has been standardized as a material for sliding bearings in various countries around the world. For example, it is the same kind of steel as AISL52100 (USA), DIN100Cr6 (West Germany), BS535A99 (UK). When the sliding bearing equipment starts, the friction coefficient is very large. After the operation, the friction coefficient is reduced, but the change is relatively small within a certain interval, and the magnitude of the change has a great influence on the friction coefficient with respect to the pressure, so the cement is in the kiln. When using fever, the method of lowering the speed of the kiln is often used. Although it has an effect, most of them cannot change the fate of fever. This is the reason. Further, in the case of impact resistance, chrome steel, chrome molybdenum steel, nickel chrome molybdenum steel, and carburizing quenching are used as bearing materials, so that the steel has a softening layer from the surface to an appropriate depth. This is a problem. In fact, the friction coefficient increases as the pressure per unit area increases. Once the friction coefficient increases, the friction heat increases. Once the heat is generated, the frictional heat is greater than the amount of heat that can be dissipated. When broken, the bearing will heat up. The carburized bearing with appropriate softening depth, fine structure, hardness-compliant surface and core hardness has excellent impact resistance compared to bearings bearing steel, and the chemical composition of individual carburized bearing steel.
The principle of self-lubricating bearings in applications
1. No oil lubrication or less oil lubrication. It is suitable for places that cannot be refueled or difficult to refuel. It can be used without maintenance or less maintenance.
2. Good wear resistance, small friction coefficient and long service life.
3. There is an appropriate amount of elastoplasticity, which can distribute the stress on the wider contact surface and improve the bearing capacity of the bearing.
4. The static friction coefficient is similar, which can eliminate the creep at low speed, thus ensuring the working precision of the machine.
Opening the package too early before use will cause internal pollution. At the same time, the dirty working environment during the installation process will cause pollution of oil-free bearings. The oil-free bearing is a novel lubricated bearing that combines the characteristics of a metal bearing with the characteristics of a non-oil-lubricated bearing. The metal matrix is subjected to a load, and the specially formulated solid lubricating material acts as a lubrication. Widely used in metallurgical continuous casting machines, rolling equipment, mining machinery, ships, steam turbines, hydraulic turbines, injection molding machines and equipment production lines. So, why are oil-free bearings widely used? Let's take a look at the following! The advantages of oil-free bearings are well known. All kinds of mechanical smooth running must use some kind of bearing.
5. It can reduce vibration, reduce noise, prevent pollution and improve working conditions.
6. The transfer film can be formed during the operation to protect the grinding shaft without biting.
7. The hardness requirement of the grinding shaft is low, and the shaft without the quenching and tempering can be used, thereby reducing the processing difficulty of the related parts.
8, thin wall structure, light weight, can reduce the mechanical volume.
9, the back of the steel can be plated with a variety of metals, can be used in corrosive media; has been widely used in various mechanical sliding parts, and some in order to improve the flexibility of the sliding bearing spherical tile, the contact between the spherical tile and the tile seat The area shrinks very small, especially the grooved spherical tile in the middle, only a small part of the groove is in contact with each other, and the friction force will increase greatly, which is not conducive to the movement of the spherical tile. For example: printing presses, textile machines, tobacco machinery, micro-motors, automobiles, motorcycles, and agricultural and forestry machinery.
Solid inlaid self-lubricating bearing introduction:
Metal-based inlaid solid self-lubricating bearing (referred to as jdb) is a novel lubricated bearing that combines the characteristics of metal bearing and the characteristics of self-lubricating bearing. The metal matrix bears the load, and the specially formulated solid lubricating material acts as a lubrication.
It has the characteristics of high bearing capacity, impact resistance, high temperature resistance and strong self-lubricating ability. It is especially suitable for heavy load, low speed, reciprocating or swinging, etc., which is difficult to lubricate and form oil film. It is also not afraid of water and other acid etching. And scouring. The cleaning of the removed bearings is divided into coarse cleaning and fine cleaning. They are placed in the container respectively, and the metal mesh bottom is placed first so that the bearing does not directly contact the container. When rough cleaning, if the bearing is rotated with dirt, it will damage the rolling surface of the bearing and should be noted. In the rough cleaning oil, use a brush to remove the grease and the adhesive. After it is almost clean, it is transferred to the fine wash. Fine washing is to carefully clean the bearing while rotating it in the cleaning oil. In addition, the cleaning oil should always be kept clean. The majority of users generally reflect that the inlaid bearing is not only fuel-efficient, energy-saving, but also has a longer working life than ordinary sliding bearings. The use of self-lubricating bearings has been widely used in metallurgical continuous casting machines, rolling equipment, mining machinery, ships, steam turbines, hydraulic turbines, injection molding machines and equipment production lines.
Most of the bearings use SUJ2 in JIS steel. Large bearings use SUJ3. The chemical composition of SUJ2 has been standardized as a material for sliding bearings in various countries around the world. For example, it is the same kind of steel as AISL52100 (USA), DIN100Cr6 (West Germany), BS535A99 (UK). When the sliding bearing equipment starts, the friction coefficient is very large. After the operation, the friction coefficient is reduced, but the change is relatively small within a certain interval, and the magnitude of the change has a great influence on the friction coefficient with respect to the pressure, so the cement is in the kiln. When using fever, the method of lowering the speed of the kiln is often used. Although it has an effect, most of them cannot change the fate of fever. This is the reason. Further, in the case of impact resistance, chrome steel, chrome molybdenum steel, nickel chrome molybdenum steel, and carburizing quenching are used as bearing materials, so that the steel has a softening layer from the surface to an appropriate depth. This is a problem. In fact, the friction coefficient increases as the pressure per unit area increases. Once the friction coefficient increases, the friction heat increases. Once the heat is generated, the frictional heat is greater than the amount of heat that can be dissipated. When broken, the bearing will heat up. The carburized bearing with appropriate softening depth, fine structure, hardness-compliant surface and core hardness has excellent impact resistance compared to bearings bearing steel, and the chemical composition of individual carburized bearing steel.
The principle of self-lubricating bearings in applications
1. No oil lubrication or less oil lubrication. It is suitable for places that cannot be refueled or difficult to refuel. It can be used without maintenance or less maintenance.
2. Good wear resistance, small friction coefficient and long service life.
3. There is an appropriate amount of elastoplasticity, which can distribute the stress on the wider contact surface and improve the bearing capacity of the bearing.
4. The static friction coefficient is similar, which can eliminate the creep at low speed, thus ensuring the working precision of the machine.
Opening the package too early before use will cause internal pollution. At the same time, the dirty working environment during the installation process will cause pollution of oil-free bearings. The oil-free bearing is a novel lubricated bearing that combines the characteristics of a metal bearing with the characteristics of a non-oil-lubricated bearing. The metal matrix is subjected to a load, and the specially formulated solid lubricating material acts as a lubrication. Widely used in metallurgical continuous casting machines, rolling equipment, mining machinery, ships, steam turbines, hydraulic turbines, injection molding machines and equipment production lines. So, why are oil-free bearings widely used? Let's take a look at the following! The advantages of oil-free bearings are well known. All kinds of mechanical smooth running must use some kind of bearing.
5. It can reduce vibration, reduce noise, prevent pollution and improve working conditions.
6. The transfer film can be formed during the operation to protect the grinding shaft without biting.
7. The hardness requirement of the grinding shaft is low, and the shaft without the quenching and tempering can be used, thereby reducing the processing difficulty of the related parts.
8, thin wall structure, light weight, can reduce the mechanical volume.
9, the back of the steel can be plated with a variety of metals, can be used in corrosive media; has been widely used in various mechanical sliding parts, and some in order to improve the flexibility of the sliding bearing spherical tile, the contact between the spherical tile and the tile seat The area shrinks very small, especially the grooved spherical tile in the middle, only a small part of the groove is in contact with each other, and the friction force will increase greatly, which is not conducive to the movement of the spherical tile. For example: printing presses, textile machines, tobacco machinery, micro-motors, automobiles, motorcycles, and agricultural and forestry machinery.
2018年12月3日星期一
Talking about the coding rules of imported bearings
The code of the imported bearing is divided into the pre-code, the basic code and the post-code. Any code must be coded in strict accordance with the coding rules. The coding rules for imported bearings are described in detail below.
1. Front code The front code of the bearing is used to indicate the sub-parts of the bearing, which are indicated by letters. For example, L denotes a separable ferrule of a separable bearing; K denotes a rolling element and a cage assembly of the bearing, and the like.
There are many types of rolling bearings for practical applications, and the corresponding bearing codes are also complicated. The code number introduced above is the most basic and most commonly used part of the bearing code. If you are familiar with this part code, you can identify and select the commonly used bearings.
2. Basic code (type code, size series code, inner diameter code) The basic code is used to indicate the inner diameter, diameter series, width series and type of the bearing, generally up to five digits, first described as follows:
1) The inner diameter of the bearing is indicated by the first and right H-digit numbers from the right of the basic code. For a common inner diameter d = 20 ~ 480mm bearing inner diameter is generally a multiple of 5, these two digits represent the quotient of the bearing inner diameter size divided by 5, such as 04 for d = 20mm; 12 for d = 60mm and so on. For bearings with inner diameters of 10 mm, 12 mm, 15 mm, and 17 mm, the inner diameter codes are 00, 01, 02, and 03 in order. For bearings with an inner diameter of less than 10 mm and greater than 500 mm, the inner diameter representation method is otherwise specified, see GB/T272-93.
2) The diameter series of the bearing (that is, the series of changes in outer diameter and width of bearings with the same structure and the same inner diameter) is represented by the third digit from the right of the basic code. For example, for a radial bearing and a radial thrust bearing, 0, 1 denotes an extra light series; 2 denotes a light series; 3 denotes a middle series; 4 denotes a heavy series. The size comparison between the series is shown in the figure below. The thrust bearing is identical to the centripetal bearing except that the 1 indicates the extra-light series.
3) The width series of the bearing (that is, the series of changes in the bearing width of the same structure, inner diameter and diameter series) is represented by the fourth digit from the right of the basic code. When the comparison of the width series of the 13-4 diameter series is 0 series (normal series), the width series code O may not be marked for most bearings in the code number, but for the spherical roller bearing and the tapered roller bearing, the width series Code 0 should be marked. Diameter series code and width series code are collectively referred to as size series code.
4) The bearing type code is represented by the fifth digit from the right of the basic code (for the type of cylindrical roller bearing and needle bearing, the letter is the letter).
3. Post code The rear code of the bearing is a letter, number, etc., indicating the structure, tolerances and special requirements of the bearing. There are many contents of the post code. Here are a few common codes.
1) The internal structure code indicates the different internal structure of the same type of bearing, which is indicated by the letter followed by the basic code. For example, angular contact ball bearings with contact angles of 15°, 25° and 40° use C, AC and B to indicate the difference in internal structure.
2) The tolerance class of the bearing is divided into 2, 4, 5, 6, 6X and 0, a total of 6 levels, from high to low, the codes are /PZ, /P4, /PS, /P6, /P6X and /PO. In the tolerance class, the 6X grade is only applicable to tapered roller bearings; the 0 grade is normal grade, and is not marked in the bearing code.
3) The commonly used radial clearance series of bearings is divided into 1 group, 2 groups, 0 groups, 3 groups, 4 groups and 5 groups, with 6 groups in total, and the radial clearance is from small to large. o Group clearance is a commonly used clearance group, which is not marked in the bearing code. The remaining clearance groups are represented by /CI, /CZ, /C3, /C4, /CS in the bearing code.
1. Front code The front code of the bearing is used to indicate the sub-parts of the bearing, which are indicated by letters. For example, L denotes a separable ferrule of a separable bearing; K denotes a rolling element and a cage assembly of the bearing, and the like.
There are many types of rolling bearings for practical applications, and the corresponding bearing codes are also complicated. The code number introduced above is the most basic and most commonly used part of the bearing code. If you are familiar with this part code, you can identify and select the commonly used bearings.
2. Basic code (type code, size series code, inner diameter code) The basic code is used to indicate the inner diameter, diameter series, width series and type of the bearing, generally up to five digits, first described as follows:
1) The inner diameter of the bearing is indicated by the first and right H-digit numbers from the right of the basic code. For a common inner diameter d = 20 ~ 480mm bearing inner diameter is generally a multiple of 5, these two digits represent the quotient of the bearing inner diameter size divided by 5, such as 04 for d = 20mm; 12 for d = 60mm and so on. For bearings with inner diameters of 10 mm, 12 mm, 15 mm, and 17 mm, the inner diameter codes are 00, 01, 02, and 03 in order. For bearings with an inner diameter of less than 10 mm and greater than 500 mm, the inner diameter representation method is otherwise specified, see GB/T272-93.
2) The diameter series of the bearing (that is, the series of changes in outer diameter and width of bearings with the same structure and the same inner diameter) is represented by the third digit from the right of the basic code. For example, for a radial bearing and a radial thrust bearing, 0, 1 denotes an extra light series; 2 denotes a light series; 3 denotes a middle series; 4 denotes a heavy series. The size comparison between the series is shown in the figure below. The thrust bearing is identical to the centripetal bearing except that the 1 indicates the extra-light series.
3) The width series of the bearing (that is, the series of changes in the bearing width of the same structure, inner diameter and diameter series) is represented by the fourth digit from the right of the basic code. When the comparison of the width series of the 13-4 diameter series is 0 series (normal series), the width series code O may not be marked for most bearings in the code number, but for the spherical roller bearing and the tapered roller bearing, the width series Code 0 should be marked. Diameter series code and width series code are collectively referred to as size series code.
4) The bearing type code is represented by the fifth digit from the right of the basic code (for the type of cylindrical roller bearing and needle bearing, the letter is the letter).
3. Post code The rear code of the bearing is a letter, number, etc., indicating the structure, tolerances and special requirements of the bearing. There are many contents of the post code. Here are a few common codes.
1) The internal structure code indicates the different internal structure of the same type of bearing, which is indicated by the letter followed by the basic code. For example, angular contact ball bearings with contact angles of 15°, 25° and 40° use C, AC and B to indicate the difference in internal structure.
2) The tolerance class of the bearing is divided into 2, 4, 5, 6, 6X and 0, a total of 6 levels, from high to low, the codes are /PZ, /P4, /PS, /P6, /P6X and /PO. In the tolerance class, the 6X grade is only applicable to tapered roller bearings; the 0 grade is normal grade, and is not marked in the bearing code.
3) The commonly used radial clearance series of bearings is divided into 1 group, 2 groups, 0 groups, 3 groups, 4 groups and 5 groups, with 6 groups in total, and the radial clearance is from small to large. o Group clearance is a commonly used clearance group, which is not marked in the bearing code. The remaining clearance groups are represented by /CI, /CZ, /C3, /C4, /CS in the bearing code.
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