When selecting NSK imported bearings, the price of bearings should be taken into account, or bearings with higher load capacity but more expensive, or ordinary bearings should be used to prolong their service life. NSK imported bearings with high load capacity are adopted, such as cylindrical roller bearings with convexity,.How to extend the three principles of NSK imported bearings.How to extend the three principles of NSK imported bearings
spherical roller bearings with symmetrical rollers, reinforced tapered roller bearings and ball bearings, ball bearings with corrected ball groove bus, or NSK imported bearings of 70000cd series are used to replace deep groove (single row centripetal) ball bearings. These bearings with high load capacity may improve the stress distribution, Or it may have higher fatigue life due to the large number of rolling elements.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
In order to select the appropriate size of NSK imported bearing, the working load, speed and operating temperature of the bearing must be accurately calculated or verified. The load has a great impact on the service life of NSK imported bearings, so although the load is difficult to measure, it should be measured as accurately as possible. When it is difficult to measure the load, the actual power consumed by the motor can be measured, and the power loss along the way can be calculated according to the transmission route and deducted until the NSK imported bearing load is closer to the actual one. How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
If the calculated or measured load is too large, the expected fatigue life of the bearing must be reduced by a greater margin, which must be remedied. If the installation position allows, NSK imported bearing with a larger size can be selected; If the radial dimension is limited, the wider bearing should be selected when there is a wider bearing; If wider bearings cannot be used, NSK imported bearings with higher load carrying capacity can be used.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
When selecting NSK imported bearing materials, its price should also be taken into account, and when vacuum smelting or electroslag remelting steel has to be used, it should be noted that the lubrication conditions must be improved in order to double the expected fatigue life of the bearing. Of course, the cost of NSK imported bearings made of this kind of high-quality steel is much higher than that of bearings with high load capacity. However, for bearings that are difficult to access in machines and are extremely difficult to assemble and disassemble, or bearings used in operation machinery in mines and tunnels, where maintenance is extremely difficult, they must still be considered sometimes.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Second, check the sound condition of NTN imported bearing during rolling. Because NTN imported bearing will emit abnormal sound and irregular sound even if there is slight peeling and other damage, it can be distinguished with a sound detector. The sound detector is used to check the rolling sound and sound quality of NTN imported bearing in operation, so as to prevent it in advance.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Third, check the temperature of NTN inlet bearing during rotation. It is more appropriate if the outer ring temperature of NTN inlet bearing can be directly measured by oil hole. Generally, the temperature of NTN inlet bearing can be inferred based on the temperature outside the NTN inlet bearing chamber. If the lubrication and installation parts are appropriate, the temperature of NTN inlet bearing will rise sharply and abnormal high temperature will occur. At this time, the operation must be stopped and necessary preventive measures must be taken.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Generally, the temperature of NTN imported bearing rises slowly with the start of operation and reaches a stable state after 1-2 hours. The normal temperature of NTN imported bearing varies with the heat capacity, heat dissipation, speed and load of the machine.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Check the axle and find out the faults existing in Peilin before long-distance or race. In the early stage, when Peilin lubrication is seriously deteriorated, eliminate these faults in advance for lubrication or replacement, so as to avoid affecting the level of play due to hardware problems, which is very important for professional drivers and amateur drivers.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Touch is a very simple method. In industry, the lubrication problem of Peilin can lead to high temperature, which can be felt by hand. This high temperature will be harmful to the lubricant in Peilin. It is difficult for the bicycle to rotate at that high speed, or even reach the ground that makes Peilin hot. The inspection touch of the bicycle is only the axis of the flower drum rotating with the hand mold, which can feel the situation inside,How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The vibration indicates that there are pits or the beads are not round, and the quicksand feeling is the lack of good lubrication. If the rotation is astringent and stuck, it indicates that the oil is dry or the wrong device has caused Peilin to be misaligned and too tight.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The observation is mainly aimed at the appearance of Peilin to see whether the rubber seal has been broken. Open the rubber seal to check whether the lubricating oil is dry. Blackening means that the lubricating oil is polluted or carbonized. Whiteness and turbidity indicates water inflow. In this case, the earlier it is found, the smaller the damage after oil change. However, the long-term use of such oil can cause irreversible damage to Peilin.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Listen, electronic stethoscope is commonly used in industry to check the condition of Peilin. The low whine indicates that Peilin is working normally, while the hiss, sharp chirp or other irregular business indicates that NTN imported bearings are in an abnormal working state.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The sharp chirp may be caused by improper lubrication, which causes metal friction, while the hissing sound may be the pollution of lubricating oil. The irregular noise is caused by the vibration caused by the indentation of the raceway. In the absence of an electronic stethoscope, the bicycle has a very simple method. Put a wooden stick on the front fork or rear fork and turn it. This method can also be used for the center axle, but it is difficult to judge because the sound of the center axle will be mixed with the rear axle. There are two kinds of lubricants commonly used in Koyo bearings: How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
lubricating oil and grease. When the circumferential speed of the shaft is less than 4-5m / s, or the parts on the vehicle that cannot be lubricated with lubricating oil, they shall be lubricated with grease. The advantage of grease lubrication is that the sealing structure is simple, the grease is not easy to lose, and it is not affected by temperature. Adding grease once can be used for a long time.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Two problems should be paid attention to when using grease. One is to select the appropriate brand of grease according to the requirements of the automobile manual. For example, nano base grease should not be selected for automobile water pump bearing because of its poor water resistance. The second is to add an appropriate amount of lubricating grease into the Koyo bearing. Generally, it is appropriate to fill only 1 / 2-L / 3 of the cavity of the Koyo bearing. Too much is not only useless, but also increases the running resistance of the Koyo bearing and heats it up. Special attention should be paid to the automobile hub bearing. It is necessary to advocate “empty hub lubrication”, that is, only apply an appropriate layer of grease on the Koyo bearing. Otherwise, it will not only waste and poor heat dissipation, but also overflow the grease by heating, which may affect the braking performance.
The advantage of lubricating oil lubrication is low friction resistance and heat dissipation. It is mainly used for Koyo bearings with high speed and high working environment temperature. The brand of lubricating oil shall be selected according to the requirements of the vehicle manual, and shall be replaced in time after the vehicle maintenance cycle. After discharging the old oil, the mechanism shall be cleaned before adding new oil. The oil shall be added to the specified marking line or flush with the oil filler (depending on the specific structure and requirements of the vehicle), and no more oil shall be added.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The assembly accuracy of cage is guaranteed by special assembly mould, which can fully meet the assembly accuracy requirements of Koyo bearing. The condition of small interference fit for the fixed ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it will be difficult to install and more difficult to disassemble. In addition, the influence of thermal elongation of the main shaft needs to be considered.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Surface heat treatment is divided into two categories. One is surface quenching and tempering heat treatment, which uses vibration absorption or vibration isolation devices to reduce Koyo bearing noise or isolate Koyo bearing noise. The other is chemical heat treatment. Its hardness test method is as follows: chemical heat treatment is to make the workpiece surface infiltrate atoms of one or more chemical elements, so as to change the chemical composition, organization and performance of the workpiece surface. How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
After quenching and low-temperature tempering, the surface of the workpiece has high hardness, wear resistance and contact fatigue strength, while the core of the workpiece has high strength and toughness.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The main technical parameters of chemical heat treatment workpiece are hardened layer depth and surface hardness. The depth of hardened layer shall be checked by Vickers hardness tester. Check the distance from the workpiece surface to the point where the hardness drops to 50HRC. This is the effective hardening depth. When the hardness of the surface of the bearing is less than 0.7mm, the hardness of the rolling Rockwell tester can not be used to check the hardness of the surface of the bearing which is not thicker than 0.7mm.
If the local hardness requirements of parts are high, local quenching heat treatment can be carried out by means of induction heating. For such parts, the location of local quenching heat treatment and local hardness value shall be marked on the drawing. The hardness inspection of parts shall be carried out in the designated area. Rockwell hardness tester can be used to test HRC hardness value. Unbalanced rotating torque – cause: incorrect installation, installation error, etc.
Timken bearing for large machinery that cannot be turned by hand, it can be started under no-load state first, and then turn off the power immediately for inertial operation. At this time, after confirming that there is no abnormal vibration or noise and the rotation is normal, enter the power operation.
When entering power operation, start at low speed and no load and gradually reach the specified operating conditions. The power operation inspection is mainly based on the sound, temperature rise and vibration. The cause shall be found out immediately, and the one-way bearing shall be removed for inspection when necessary.
For the one-way sound inspection of Timken bearing, generally, a sound stick can be used.
The temperature inspection of one-way bearing can generally be speculated according to the shell temperature, but it is correct to directly measure the temperature of the outer ring of one-way bearing by using oil hole, etc.
The grinding layer, high-temperature layer and two-layer quenching of Timken bearing are treated in molten state. The molten metal molecular flow is uniformly coated on the working surface and cooled by the base metal at a very fast speed, forming an extremely thin amorphous structure layer. It has high hardness and toughness, but it is only about 10nm, which is easy to be removed in precision grinding.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
The instantaneous high temperature in the grinding area of Timken bearing can make the surface heated to a certain depth (10 ~ 100nm) higher than the tempering heating temperature of the workpiece. When the austenitizing temperature is not reached, with the increase of the heating temperature, the surface layer by layer will produce the microstructure transformation of re tempering or high-temperature tempering corresponding to the heating temperature, and the hardness will also decrease. The higher the heating temperature, the more severe the decrease of hardness.How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Timken bearing when the instantaneous high temperature in the grinding area heats the surface layer of the workpiece above the austenitizing temperature (AC1), the austenitized structure of the layer will be re quenched into martensitic structure in the subsequent cooling process. For the workpiece with secondary quenching burn, the high-temperature tempering layer with very low hardness must be under the secondary quenching layer. When examining the advantages of chromium steel and stainless steel as fag bearing materials, it is found that they do not only have anti rust effect. Chromium steel is a common fag bearing material. It is harder than stainless steel, so it has a longer service life. However, at higher temperatures, its performance is not very good.
At the high temperature of 120c, it will undergo huge deformation and reduce the load. The continuous high temperature of 150C can be tolerated, but the instantaneous temperature of 150C or higher will reduce the service life of fag bearing. Heat treatment can make fag bearing bear the high temperature of 170C at an instant.
The 440 stainless steel commonly used for fag bearing is hard and firm enough to carry load (20% less than Brass Steel), but it can prevent rust and can withstand the instantaneous high temperature of 250C and the continuous high temperature of 300C. We often mistakenly think that all stainless steel is non-magnetic, and 440 stainless steel is magnetic. It is not completely rustproof, but affected by salt, acid and alkali.
Grade 316 has good antirust performance, no magnetism, but it is relatively soft, so it has less load. Because it is not firm, the accuracy of 316fag bearing is not high and feels rough. Timken imported bearings must be installed under dry and clean environmental conditions. Before installation, carefully check the machining quality of the mating surface of the shaft and housing, the end face of the shoulder, the groove and the connecting surface. All mating connection surfaces must be carefully cleaned and deburred, and the unprocessed surface of the casting must be cleaned of molding sand.
Timken imported bearings shall be cleaned before installation and used after drying, and good lubrication shall be ensured. The bearings are generally lubricated with grease or oil. When grease lubrication is used, grease with excellent properties such as no impurities, oxidation resistance, rust prevention and extreme pressure shall be selected. The filling amount of lubricating grease is 30% – 60% of the volume of bearing and bearing box, which should not be too much. The double row tapered roller bearing with sealing structure and the shaft connecting bearing of water pump have been filled with grease, which can be directly used by users and can not be cleaned.
When installing the bearing, equal pressure must be applied on the circumference of the ferrule end face to press the ferrule in. It is not allowed to directly knock the bearing end face with hammers and other tools to avoid damaging the bearing. When the interference is small, press the end face of the bearing ring with the sleeve at room temperature, knock the sleeve with a hammer, and press the ring evenly through the sleeve. If it is installed in large quantities, hydraulic press can be used. When pressing in, ensure that the end face of the outer ring and the end face of the housing shoulder, the end face of the inner ring and the end face of the shaft shoulder are pressed tightly, and there is no gap.
When the interference is large, the bearing can be installed by oil bath heating or inductor heating. The heating temperature range is 80 ℃ – 100 ℃, and the height cannot exceed 120 ℃. At the same time, tighten the bearing with nuts or other appropriate methods to prevent the gap between the ferrule and the shaft shoulder caused by the width contraction of Timken inlet bearing after cooling.
The clearance of single row tapered roller bearing shall be adjusted after installation. The clearance value shall be determined according to different working conditions and the interference of the fit. If necessary, it shall be determined by test. The clearance of double row tapered roller bearing and water pump shaft connecting bearing has been adjusted at the factory, so it is not necessary to adjust it during installation.
Timken imported bearings shall be installed with rotation test. First, they shall be used for rotating shaft or bearing box. If there is no abnormality, they can run at no-load and low speed with power, and then gradually increase the rotation speed and load according to the operation, and detect the noise, vibration and temperature rise. If any abnormality is found, they shall stop running and check. It can be delivered for use only after the operation test is normal.
How to extend the three principles of NSK imported bearingsHow to extend the three principles of NSK imported bearings
Check the axle and find out the faults existing in Peilin before long-distance or race. In the early stage, when Peilin lubrication is seriously deteriorated, eliminate these faults in advance for lubrication or replacement, so as to avoid affecting the level of play due to hardware problems, which is very important for professional drivers and amateur drivers.How to extend the three principles of NSK imported bearings
Touch is a very simple method. In industry, the lubrication problem of Peilin can lead to high temperature, which can be felt by hand. This high temperature will be harmful to the lubricant in Peilin. It is difficult for the bicycle to rotate at that high speed, or even reach the ground that makes Peilin hot.How to extend the three principles of NSK imported bearings
The inspection touch of the bicycle is only the axis of the flower drum rotating with the hand mold, which can feel the situation inside, The vibration indicates that there are pits or the beads are not round, and the quicksand feeling is the lack of good lubrication. If the rotation is astringent and stuck, it indicates that the oil is dry or the wrong device has caused Peilin to be misaligned and too tight.How to extend the three principles of NSK imported bearings
The observation is mainly aimed at the appearance of Peilin to see whether the rubber seal has been broken. Open the rubber seal to check whether the lubricating oil is dry. Blackening means that the lubricating oil is polluted or carbonized. Whiteness and turbidity indicates water inflow. In this case, the earlier it is found, the smaller the damage after oil change. However, the long-term use of such oil can cause irreversible damage to Peilin.How to extend the three principles of NSK imported bearings
Listen, electronic stethoscope is commonly used in industry to check the condition of Peilin. The low whine indicates that Peilin is working normally, while the hiss, sharp chirp or other irregular business indicates that NTN imported bearings are in an abnormal working state.How to extend the three principles of NSK imported bearings
The sharp chirp may be caused by improper lubrication, which causes metal friction, while the hissing sound may be the pollution of lubricating oil. The irregular noise is caused by the vibration caused by the indentation of the raceway. In the absence of an electronic stethoscope, the bicycle has a very simple method. Put a wooden stick on the front fork or rear fork and turn it. This method can also be used for the center axle, but it is difficult to judge because the sound of the center axle will be mixed with the rear axle. How to extend the three principles of NSK imported bearings
There are two kinds of lubricants commonly used in Koyo bearings: lubricating oil and grease. When the circumferential speed of the shaft is less than 4-5m / s, or the parts on the vehicle that cannot be lubricated with lubricating oil, they shall be lubricated with grease. The advantage of grease lubrication is that the sealing structure is simple, the grease is not easy to lose, and it is not affected by temperature. Adding grease once can be used for a long time.How to extend the three principles of NSK imported bearings
Two problems should be paid attention to when using grease. One is to select the appropriate brand of grease according to the requirements of the automobile manual. For example, nano base grease should not be selected for automobile water pump bearing because of its poor water resistance. The second is to add an appropriate amount of lubricating grease into the Koyo bearing. How to extend the three principles of NSK imported bearings
Generally, it is appropriate to fill only 1 / 2-L / 3 of the cavity of the Koyo bearing. Too much is not only useless, but also increases the running resistance of the Koyo bearing and heats it up. Special attention should be paid to the automobile hub bearing. It is necessary to advocate “empty hub lubrication”, that is, only apply an appropriate layer of grease on the Koyo bearing. Otherwise, it will not only waste and poor heat dissipation, but also overflow the grease by heating, which may affect the braking performance.How to extend the three principles of NSK imported bearings
The advantage of lubricating oil lubrication is low friction resistance and heat dissipation. It is mainly used for Koyo bearings with high speed and high working environment temperature. The brand of lubricating oil shall be selected according to the requirements of the vehicle manual, and shall be replaced in time after the vehicle maintenance cycle. After discharging the old oil, the mechanism shall be cleaned before adding new oil. The oil shall be added to the specified marking line or flush with the oil filler (depending on the specific structure and requirements of the vehicle), and no more oil shall be added.How to extend the three principles of NSK imported bearings
The assembly accuracy of cage is guaranteed by special assembly mould, which can fully meet the assembly accuracy requirements of Koyo bearing. The condition of small interference fit for the fixed ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it will be difficult to install and more difficult to disassemble. In addition, the influence of thermal elongation of the main shaft needs to be considered.How to extend the three principles of NSK imported bearings
Surface heat treatment is divided into two categories. One is surface quenching and tempering heat treatment, which uses vibration absorption or vibration isolation devices to reduce Koyo bearing noise or isolate Koyo bearing noise. The other is chemical heat treatment. Its hardness test method is as follows: chemical heat treatment is to make the workpiece surface infiltrate atoms of one or more chemical elements, so as to change the chemical composition, organization and performance of the workpiece surface.How to extend the three principles of NSK imported bearings
After quenching and low-temperature tempering, the surface of the workpiece has high hardness, wear resistance and contact fatigue strength, while the core of the workpiece has high strength and toughness.How to extend the three principles of NSK imported bearings
The main technical parameters of chemical heat treatment workpiece are hardened layer depth and surface hardness. The depth of hardened layer shall be checked by Vickers hardness tester. Check the distance from the workpiece surface to the point where the hardness drops to 50HRC. This is the effective hardening depth. When the hardness of the surface of the bearing is less than 0.7mm, the hardness of the rolling Rockwell tester can not be used to check the hardness of the surface of the bearing which is not thicker than 0.7mm.How to extend the three principles of NSK imported bearings
If the local hardness requirements of parts are high, local quenching heat treatment can be carried out by means of induction heating. For such parts, the location of local quenching heat treatment and local hardness value shall be marked on the drawing. The hardness inspection of parts shall be carried out in the designated area. Rockwell hardness tester can be used to test HRC hardness value. Unbalanced rotating torque – cause: incorrect installation, installation error, etc.How to extend the three principles of NSK imported bearings
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