NSK bearing failure analysis and processing of cement machinery
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A rolling bearing failure analysis
1.1 rolling bearing vibration analysis
The typical way to scroll the FAG bearing failure is the rolling contact of simple fatigue spalling. This spalling, peeling off the surface area of ??approximately such as 2 mm2, depth up to 0.2mm ~ 0.3mm can be judged through the monitor to review its vibration. Peeling may occur, including the seat surface, the outer race or rolling element. Among them, the inner race due to higher contact stress, the rupture of the situation more.
Various types of diagnostic techniques for rolling bearings, vibration monitors monitoring method is still the most important kind. Overall, the time-domain analysis method is simple, suitable for small occasions of noise, is a good way of simple diagnostic; diagnostic method in the frequency domain, resonance demodulation method is the most mature and reliable, suitable for the precision diagnosis of bearing failure; time - frequency analysis method is similar to the resonance demodulation method can accurately characterize the time and frequency characteristics of the fault signal has more advantages.
1.2 rolling bearing damage in the form of analysis and remedies
(1) overload. Severe surface spalling and wear, indicating that the SKF rolling bearings due to overload caused early fatigue failure (in addition to tie too tight can also cause a certain degree of fatigue). Overload can also cause serious bearing ball raceway wear, peeling off a large area, sometimes accompanied by overheating. The remedy is to reduce the bearing load or load capacity.
(2) overheating. Roller, roller, ball or maintain change color, indicating that the bearing overheating. Lubricant role of temperature will reduce oil desert is not easy to form or disappear completely. High temperature annealing make the raceway and ball material, the hardness decreases. This is mainly thermal adverse or overload, high-speed cooling is not fully caused. The solution is fully cooling, additional cooling.
(3) low-load vibration eclipse. This indicates that when the bearing does not work do not result in the lubricant film failure caused by external vibration over-or low-load vibration eclipse oval signs of wear, the axial position of each ball. The remedy is to NTN Bearing isolation or to join the anti-wear additives in the bearing grease.
(4) installation problems. The main attention to the following aspects:
First, note that the installation force. Such as the raceway interval pressure pit, indicating that the load beyond the elastic limit of the material. This is caused due to static overload or severe shock (such as the installation had with a hammer bearing). The correct method of installation is only pressing force of the loop (Do not push the shaft mounted inner outer).
Second, pay attention to the mounting direction of angular contact bearings. Angular contact spindle NACHI bearing contact area with an oval-shaped, and withstand the axial thrust in one direction only. Due to the ball bearing assembly in the opposite direction at the edge of the raceway, the loading surface will produce trough the wear. Therefore, the installation should pay attention to correct installation direction.
Third, pay attention to the pair. The worn trace deflection, not parallel with the direction of the raceway, show that when installing the bearing is not. If the deflection is> 16000, it is easy to cause the bearing temperature rise and severe wear. Its causes may be axis bending, shaft or box glitches, the compression side of the lock mother is not with the thread axis vertical and so on. Therefore, the installation should be careful to check the diameter jump.
Fourth, we should pay attention to the correct co-ordination. The bearing outer ring assembly contact surface wear or discoloration of the circular-shaped, is caused by loose bearings with matching parts with. Oxide abrasive produce a pure brown abrasive, the result will cause the bearings to further wear and tear, heat and noise and produce a range of issues such as diameter jump, the assembly should be aware of the correct co-ordination.
Another example is the bottom of the raceway spherical wear track, suggesting that with tight bearing clearance is smaller, the torque increases, the bearing temperature rise, bearing soon due to wear and fatigue failure. At this point, as long as the appropriate restore the radial clearance, reducing the amount of interference can solve this problem.
(5) the IKO bearing normal fatigue failure. Irregular material peeling off in any one operation of the surface (such as roller or ball), and gradually extended to cause amplitude increase, which is a normal fatigue failure. If the life of ordinary bearings can not meet the requirements, only to re-selection of more advanced bearing, or improving a bearing specifications to improve the carrying capacity of the bearing.
(6) improper lubrication. All rolling bearing with high quality lubricant for continuous lubrication to maintain its design performance. Rely on a layer of film formed on the rolling element and the seat to prevent direct contact between the metal and metal bearing. If the lubrication is good, we can reduce the friction so that it will not wear.
Bearing in running state, the viscosity of the grease or oil is to ensure that the key to its normal lubrication;, grease kept clean, free of solid or liquid impurities is also essential. Oil viscosity is too low, can not play the full lubrication quickly wear to the seat. The beginning, the metal surface of the metal seat and rolling element with each other direct contact with friction, so that the polished surface is very smooth the ? subsequent dry friction the ? cause the surface of the seat ring rolling surface of crushed grain crumbs are fracturing. Can be observed at first to the surface darken, lose their luster, and finally the formation of dents and flaky fatigue off. Remedies in accordance with the bearings need to re-choose to replace oil or fat.
Pollutants of particulate contamination in lubricating oil or grease, even though these pollutant particles less than the average film thickness, but the particle is very hard the ? will continue to produce wear, and even penetrate the film and the local stress, resulting in the bearing surface, thus significantly shorten the TIMKEN bearing life. Even if the concentration of oil or grease in water to 0.01%, is sufficient to shorten the half of the bearing of the original life. Flow is soluble in oil or fat, and increasing concentrations of reduced bearing life will be over water. The remedy is to swap not clean oil or grease; usually a good filter should be installed to increase the sealing, storage, installation, pay attention to cleaning operations.
(7) corrosion. Raceway, steel ball, keep the frame and inside and outside the loop surface appear red or brown stain, and that the bearings exposed to corrosive liquids or gases corrosion failure. It will cause the vibration increases, increased wear and tear, increased radial clearance, pre-loaded to reduce the fatigue failure, and in the limit case. The remedy is to make the liquid discharged from the bearing or increase the overall bearing and outer seal.
INA Bearing failure causes and treatment of the two fan
According to incomplete statistics, the cement plant fan abnormal vibration of the highest failure rate of 58.6 percent, due to vibration caused by unbalanced fan operation. Among them, bearing adapter sleeve with the adjustment of misconduct will result in the bearing abnormal temperature rise and vibration.
Such as a cement plant during maintenance of equipment to replace the fan vane. The round leaves on both sides with tight sleeve bearing bearing fixed complexes. Re-test took place the free end bearing high temperature, high vibration value of the fault.
Disassemble bearing cover, manual slow rotary fan, found in the shaft of a particular position of the bearing roller, bearing running clearance changes in the high installation gap may be less than in the non-load area also scroll, can be determined. Learned by measuring bearing internal clearance of only 0.04mm, shaft eccentricity up to 0.18mm.
About NACHI bearing span, to avoid the installation angle of the shaft deflection or bearing error is more difficult, therefore, the large fan automatically on the heart to adjust the spherical roller bearings. However, when the bearing internal clearance less than the bearing internal rolling due to movement space limitations, the automatic function of the heart affected, the vibration values ??it will rise. Bearing temperature, bearing internal clearance with with the tightness of the decreases, the lubricant film can not be formed when the bearing running clearance due to temperature rise and reduced to zero, if the bearing is running the heat generated is still greater than the dissipation of heat will quickly climb. At this time, if not immediate shutdown, the bearings will eventually burn. Bearing inner ring and shaft with tight abnormal high temperature bearing operation in this case.
Processing step down tight sleeve, re-adjust the shaft and inner ring with the tightness, replace the bearing clearance after taking 0.10mm. Re-installed restart the fan bearing vibration values ??and operating temperature were normal.
Poor bearing internal clearance is too small or mechanical design and manufacture of precision are the main cause of high bearing operating temperature, to facilitate the installation of wi nd turbine equipment, overhaul and maintenance, generally in the design of multi-tight sleeve bearings tapered bore inner ring with the the bearing bearing. However, also easy because of the negligence of the installer has encountered a problem, especially the proper gap adjustment. Bearing internal clearance is too small, rapid increase in operating temperature; bearing inner ring tapered bore and adapter sleeve tie too loose of bearings failure in the short term burning due to the mating surface loose.
3 Conclusion
In summary, bearing failure, it should be in aspects of the design, maintenance and lubrication management, operation, use attention. This can reduce the maintenance costs of machinery and equipment, to extend the operation rate and service life of machinery and equipment.
234407BM 234706BM 234406BM 517/2860V/YA 5610/2500 517/1720X1V 527/1181M 510/1180M 517/930 510/670 590/560 510/500 52780 59080 517/368M 51760U 517/238 6207-2ZN 6206-2ZN 6205-2ZN 6204-2ZN 6203-RZ 6203-2ZN 6202N 6202-2ZN 6201-2ZN 6200ZZ 6200-2ZN 62/32-ZN 62/32-Z 62/32N 62/32-2Z 62/32-2RZ 62/32-2RS 62/28-2RZ 62/22-2RZ 61996 61992 61988 61984
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The bearings of the machinery and equipment are vulnerable parts of its operation status is a direct impact on the performance of the device. Cement machinery and equipment, many instances of equipment failure caused by the early failures of rolling bearings. Therefore, identifying the root cause failure to take remedial measures to eliminate the fault, is one of the keys to improve the rate of operation of the system.A rolling bearing failure analysis
1.1 rolling bearing vibration analysis
The typical way to scroll the FAG bearing failure is the rolling contact of simple fatigue spalling. This spalling, peeling off the surface area of ??approximately such as 2 mm2, depth up to 0.2mm ~ 0.3mm can be judged through the monitor to review its vibration. Peeling may occur, including the seat surface, the outer race or rolling element. Among them, the inner race due to higher contact stress, the rupture of the situation more.
Various types of diagnostic techniques for rolling bearings, vibration monitors monitoring method is still the most important kind. Overall, the time-domain analysis method is simple, suitable for small occasions of noise, is a good way of simple diagnostic; diagnostic method in the frequency domain, resonance demodulation method is the most mature and reliable, suitable for the precision diagnosis of bearing failure; time - frequency analysis method is similar to the resonance demodulation method can accurately characterize the time and frequency characteristics of the fault signal has more advantages.
1.2 rolling bearing damage in the form of analysis and remedies
(1) overload. Severe surface spalling and wear, indicating that the SKF rolling bearings due to overload caused early fatigue failure (in addition to tie too tight can also cause a certain degree of fatigue). Overload can also cause serious bearing ball raceway wear, peeling off a large area, sometimes accompanied by overheating. The remedy is to reduce the bearing load or load capacity.
(2) overheating. Roller, roller, ball or maintain change color, indicating that the bearing overheating. Lubricant role of temperature will reduce oil desert is not easy to form or disappear completely. High temperature annealing make the raceway and ball material, the hardness decreases. This is mainly thermal adverse or overload, high-speed cooling is not fully caused. The solution is fully cooling, additional cooling.
(3) low-load vibration eclipse. This indicates that when the bearing does not work do not result in the lubricant film failure caused by external vibration over-or low-load vibration eclipse oval signs of wear, the axial position of each ball. The remedy is to NTN Bearing isolation or to join the anti-wear additives in the bearing grease.
(4) installation problems. The main attention to the following aspects:
First, note that the installation force. Such as the raceway interval pressure pit, indicating that the load beyond the elastic limit of the material. This is caused due to static overload or severe shock (such as the installation had with a hammer bearing). The correct method of installation is only pressing force of the loop (Do not push the shaft mounted inner outer).
Second, pay attention to the mounting direction of angular contact bearings. Angular contact spindle NACHI bearing contact area with an oval-shaped, and withstand the axial thrust in one direction only. Due to the ball bearing assembly in the opposite direction at the edge of the raceway, the loading surface will produce trough the wear. Therefore, the installation should pay attention to correct installation direction.
Third, pay attention to the pair. The worn trace deflection, not parallel with the direction of the raceway, show that when installing the bearing is not. If the deflection is> 16000, it is easy to cause the bearing temperature rise and severe wear. Its causes may be axis bending, shaft or box glitches, the compression side of the lock mother is not with the thread axis vertical and so on. Therefore, the installation should be careful to check the diameter jump.
Fourth, we should pay attention to the correct co-ordination. The bearing outer ring assembly contact surface wear or discoloration of the circular-shaped, is caused by loose bearings with matching parts with. Oxide abrasive produce a pure brown abrasive, the result will cause the bearings to further wear and tear, heat and noise and produce a range of issues such as diameter jump, the assembly should be aware of the correct co-ordination.
Another example is the bottom of the raceway spherical wear track, suggesting that with tight bearing clearance is smaller, the torque increases, the bearing temperature rise, bearing soon due to wear and fatigue failure. At this point, as long as the appropriate restore the radial clearance, reducing the amount of interference can solve this problem.
(5) the IKO bearing normal fatigue failure. Irregular material peeling off in any one operation of the surface (such as roller or ball), and gradually extended to cause amplitude increase, which is a normal fatigue failure. If the life of ordinary bearings can not meet the requirements, only to re-selection of more advanced bearing, or improving a bearing specifications to improve the carrying capacity of the bearing.
(6) improper lubrication. All rolling bearing with high quality lubricant for continuous lubrication to maintain its design performance. Rely on a layer of film formed on the rolling element and the seat to prevent direct contact between the metal and metal bearing. If the lubrication is good, we can reduce the friction so that it will not wear.
Bearing in running state, the viscosity of the grease or oil is to ensure that the key to its normal lubrication;, grease kept clean, free of solid or liquid impurities is also essential. Oil viscosity is too low, can not play the full lubrication quickly wear to the seat. The beginning, the metal surface of the metal seat and rolling element with each other direct contact with friction, so that the polished surface is very smooth the ? subsequent dry friction the ? cause the surface of the seat ring rolling surface of crushed grain crumbs are fracturing. Can be observed at first to the surface darken, lose their luster, and finally the formation of dents and flaky fatigue off. Remedies in accordance with the bearings need to re-choose to replace oil or fat.
Pollutants of particulate contamination in lubricating oil or grease, even though these pollutant particles less than the average film thickness, but the particle is very hard the ? will continue to produce wear, and even penetrate the film and the local stress, resulting in the bearing surface, thus significantly shorten the TIMKEN bearing life. Even if the concentration of oil or grease in water to 0.01%, is sufficient to shorten the half of the bearing of the original life. Flow is soluble in oil or fat, and increasing concentrations of reduced bearing life will be over water. The remedy is to swap not clean oil or grease; usually a good filter should be installed to increase the sealing, storage, installation, pay attention to cleaning operations.
(7) corrosion. Raceway, steel ball, keep the frame and inside and outside the loop surface appear red or brown stain, and that the bearings exposed to corrosive liquids or gases corrosion failure. It will cause the vibration increases, increased wear and tear, increased radial clearance, pre-loaded to reduce the fatigue failure, and in the limit case. The remedy is to make the liquid discharged from the bearing or increase the overall bearing and outer seal.
INA Bearing failure causes and treatment of the two fan
According to incomplete statistics, the cement plant fan abnormal vibration of the highest failure rate of 58.6 percent, due to vibration caused by unbalanced fan operation. Among them, bearing adapter sleeve with the adjustment of misconduct will result in the bearing abnormal temperature rise and vibration.
Such as a cement plant during maintenance of equipment to replace the fan vane. The round leaves on both sides with tight sleeve bearing bearing fixed complexes. Re-test took place the free end bearing high temperature, high vibration value of the fault.
Disassemble bearing cover, manual slow rotary fan, found in the shaft of a particular position of the bearing roller, bearing running clearance changes in the high installation gap may be less than in the non-load area also scroll, can be determined. Learned by measuring bearing internal clearance of only 0.04mm, shaft eccentricity up to 0.18mm.
About NACHI bearing span, to avoid the installation angle of the shaft deflection or bearing error is more difficult, therefore, the large fan automatically on the heart to adjust the spherical roller bearings. However, when the bearing internal clearance less than the bearing internal rolling due to movement space limitations, the automatic function of the heart affected, the vibration values ??it will rise. Bearing temperature, bearing internal clearance with with the tightness of the decreases, the lubricant film can not be formed when the bearing running clearance due to temperature rise and reduced to zero, if the bearing is running the heat generated is still greater than the dissipation of heat will quickly climb. At this time, if not immediate shutdown, the bearings will eventually burn. Bearing inner ring and shaft with tight abnormal high temperature bearing operation in this case.
Processing step down tight sleeve, re-adjust the shaft and inner ring with the tightness, replace the bearing clearance after taking 0.10mm. Re-installed restart the fan bearing vibration values ??and operating temperature were normal.
Poor bearing internal clearance is too small or mechanical design and manufacture of precision are the main cause of high bearing operating temperature, to facilitate the installation of wi nd turbine equipment, overhaul and maintenance, generally in the design of multi-tight sleeve bearings tapered bore inner ring with the the bearing bearing. However, also easy because of the negligence of the installer has encountered a problem, especially the proper gap adjustment. Bearing internal clearance is too small, rapid increase in operating temperature; bearing inner ring tapered bore and adapter sleeve tie too loose of bearings failure in the short term burning due to the mating surface loose.
3 Conclusion
In summary, bearing failure, it should be in aspects of the design, maintenance and lubrication management, operation, use attention. This can reduce the maintenance costs of machinery and equipment, to extend the operation rate and service life of machinery and equipment.
