I believe that everyone must have encountered the new bearing after it has been installed. At this time, we must think of returning, but the bearing sound must be the quality of the product? I will share some ideas for you today and hope to help you. Normal running bearing sound
1. If the bearing is in a good continuous rotation state, it will emit a low or low humming sound. If a sharp voice is heard, the voice and other irregular sounds often indicate that the bearing is in a bad transition condition. Sharp squeaking noise can be caused by improper lubrication. Improper bearing clearance can also cause metallic sound.
2. The dent on the outer ring of the bearing will cause vibration and cause a smooth and crisp sound.
3. If there is intermittent noise, it means the rolling parts may be damaged. This sound occurs when there is a contaminant in the bearing when the damaged surface is crushed. Severe bearing damage can result in irregular and large noise. 4. If the knocking damage caused by the installation will also produce noise, the noise will vary with the speed of the bearing. Abnormal bearing noise
►Large metal noise
Reason 1: Abnormal load, countermeasures: Correct the fit, study bearing clearance, adjust and load, and correct the position of the housing shoulder. Cause 2: Poor installation, countermeasures: Machining accuracy of shaft and outer casing, improvement of mounting accuracy, and installation method. Cause 3: The lubricant is insufficient or unsuitable. Countermeasure: Replenish the lubricant and select the appropriate lubricant. Cause 4: The rotating parts are in contact. Countermeasure: Modify the contact part of the curved path seal. ►Regular noise
Cause 1: Indentation, rust, or scratch on the rolling surface due to foreign matter. Countermeasures: Replace the bearing, clean the parts, improve the sealing device, and use a clean lubricant. Reason 2: (after steel carburization) surface deformation, countermeasures: replace the bearing, pay attention to its use. Cause 3: The raceway surface is peeled off. Countermeasure: Replace the bearing. ► Irregular noise
Reason 1: The clearance is too large. Countermeasure: Study the fit and bearing clearance, and modify the preload. Reason 2: Intrusion of foreign matter, countermeasures: Study replacement of bearings, cleaning related parts, improving sealing devices, and using clean lubricants. Cause 3: Spherical injury, peeling, countermeasure: Replace the bearing. 30 reasons why the bearing is ringing
1. Grease has impurities; 2. Insufficient lubrication (oil level is too low, improper storage causes oil or grease to leak through the seal); 3. The clearance of the bearing is too small or too large (production plant problem); 4. Mixing in the bearing Impurities such as sand or carbon particles act as an abrasive; 5. The bearing is mixed with water, acid or paint and other contaminants, causing corrosion; 6. The bearing is flattened by the seat hole (the roundness of the seat hole is not good) , or the seat hole is not twisted straight; 7. The horn of the bottom of the bearing seat is not flat (resulting in the deformation of the seat hole or even the crack of the bearing seat); 8. There are debris in the hole of the bearing housing (residue of chips, dust particles, etc.); 9. The seal is eccentric (wearing adjacent parts and rubbing); 10. The bearing is subjected to additional load (the bearing is axially tightened, or there are two fixed end bearings on one shaft); 11. Bearing and shaft fit Too loose (the diameter of the shaft is too small or the adapter sleeve is not tightened); 12. The clearance of the bearing is too small, too tight when rotating (the tightening sleeve is too tight); 13. The bearing is noisy (roller The end face or the steel ball is slipped); 14. The thermal elongation of the shaft is too large (the bearing is subjected to static and indeterminate axial additional load); 15. The shoulder is too large (the seal of the bearing is encountered and friction occurs) 16. The shoulder of the seat hole is too large (the seal of the bearing is twisted); 17. The gap of the labyrinth seal is too small (friction with the shaft); 18. The tooth of the lock washer is bent (touching the bearing) And the friction occurs); 19. The position of the oil ring is not suitable (the flange cover is encountered and friction occurs); 20. There is a pressure pit on the steel ball or roller (caused by hammer hitting the bearing during installation); 21. Bearing There is noise (with external vibration source interference); 22. The bearing is heated and discolored and deformed (caused by the use of a spray gun to dismantle the bearing); 23. The shaft is too thick to make the actual fit too tight (causing the bearing temperature to be too high or noise); The diameter of the seat hole is too small (causing the bearing temperature to be too high); 25. The diameter of the bearing housing hole is too large, the actual fit is too loose (the bearing temperature is too high - the outer ring is slipping); 26. The bearing seat hole becomes larger (non-ferrous metal The bearing housing bore is enlarged or enlarged due to thermal expansion); 27. The cage is broken. 28. The bearing raceway is rusty. 29. Steel ball, raceway wear (unqualified grinding or product damage). 30. The ferrule raceway is unqualified (manufacturer problem). Detection method and instrument for abnormal sound of bearing
There are currently two ways to detect abnormal sounds in bearings. One is acoustic-based noise detection and the other is vibration-based detection.
(1) Noise detection method:
In the muffler environment with the basic noise less than 20db, the high-quality microphone is used to extract the bearing sound pressure signal at a certain distance and direction, and the abnormal sound component is extracted by a certain analysis method, which is a direct measurement method of abnormal sound. (2) Vibration detection method:
It is an indirect detection method for abnormal sounds, and can be divided into qualitative detection method and quantitative parameter detection method. Among them, the qualitative detection method is divided into the monitoring abnormal sound method and the observation vibration waveform method. The quantitative parameter detection method refers to the evaluation of the abnormal sound of the bearing by using the measured parameter values related to the abnormal sound in the vibration signal of the tested bearing, such as the peak value of the vibration and the crest factor. (3) Measuring instruments for measuring abnormal sound of bearings:
There are many measuring instruments for measuring abnormal sound of bearings, for example: BANT-1 bearing abnormal sound monitor of Hangzhou Bearing Test Research Center; S092 bearing vibration (abnormal sound) measuring instrument of Shanghai Bearing Technology Research Institute; Luoyang Bearing Research Institute and Dalian Bearing S0910-III jointly developed by the instrument factory. These bearing measuring instruments can measure the effective value of bearing vibration and measure the peak value, crest factor and pulse number of the abnormal acoustic parameters of the bearing. 1 Simple diagnosis of rolling bearings The acupuncture method is used to monitor the condition of the bearing by touching one end of the tool such as the needle and the outer casing of the bearing to be tested, and the other end is placed at the ear hole of the tester to hear the sound inside the bearing. A common tool for monitoring the working condition of a rolling bearing by auscultation is a stylus or a long-hand screw with a wooden handle, or a hard plastic tube with an outer diameter of about φ20 mm. 1.1 Acoustic characteristics of rolling bearing in normal working condition When the rolling bearing is in normal working condition, the running is smooth, brisk, no stagnation, the sound is harmonious and no noise, and a uniform and continuous “beep” sound can be heard, or lower “ Booming. The noise intensity is not large. 1.2 Bearing failure reflected by abnormal sound (1) The bearing emits a uniform and continuous “click” sound. This sound is generated by the rolling element rotating inside and outside the picture, and contains irregular metal vibration sounds independent of the rotation speed. Generally, the amount of fat in the bearing is insufficient and should be supplemented. If the equipment is out of downtime for a long time, especially in the low temperature conditions in winter, the sound of “sand sand” will sometimes sound during the bearing operation, which is related to the smaller radial clearance of the bearing and the smaller penetration of the grease. The bearing clearance should be properly adjusted to replace the new grease with a lower viscosity. (2) The bearing emits a uniform periodic "嗬" sound in a continuous "哗哗" sound. This sound is caused by flaws, grooves, and rust spots on the rolling elements and the inner and outer ring raceways. The period of the sound is proportional to the speed of the bearing. Bearings should be replaced. (3) The bearing emits a discontinuous "stalk" sound which is caused by the rupture of the cage or the inner and outer rings. The bearing must be replaced immediately. (4) The bearing emits an irregular, uneven “beep” sound. This sound is caused by impurities such as iron filings and sand grains falling inside the bearing. The sound intensity is small and has no connection with the number of revolutions. The bearings should be cleaned, regreased or oil changed. (5) The bearing emits a continuous and irregular "sand" sound. This sound is generally related to the loose fit of the inner ring of the bearing and the shaft or the loose fit of the outer ring with the bearing hole. When the sound intensity is large, the bearing relationship should be checked and the problem should be repaired in time. (6) The bearing emits a continuous squeaking sound. This sound is caused by poor lubrication of the bearing or lack of oil, or the local contact of the rolling element is too tight, such as the inner and outer ring raceways are skewed, and the inner and outer rings of the bearing are too tight. caused. The bearings should be inspected in time to identify the problem and treat it symptomatically. 2 Bearing peeling phenomenon and its causes 2.1 Bearing peeling phenomenon When the bearing is subjected to load rotation, the rolling surface of the inner ring, the outer ring or the rolling surface of the rolling element is scaly-like peeling off due to the rolling fatigue Billet phenomenon. 2.2 Main causes of bearing peeling (1) Surface deformation such as raw embroidery, erosion points, bruises and indentations caused by foreign matter intrusion or water ingress and poor lubrication selection. (2) The load is too large; the mechanical damage caused by the installation of a bad torque load. (3) Mechanical crushing or impact damage caused by improper installation of the tightness. (4) The deflection of the shaft is large, the accuracy of the bearing housing is not good, and the mechanical vibration shock damage caused by uneven rigidity. (5) Uneven stress caused by improper bearing quality and oil gap, and local impact damage. 3 Type of damage (1) One-way angular contact ball bearings are generally bearings that are subjected to one-way thrust and positioning. The peeling phenomenon of the inner ring of the one-way radial angular contact ball bearing along the halfway of the raceway surface causes the damage mainly due to the large deflection of the shaft, the one-way force and the intrusion of the cutting fluid, resulting in poor lubrication. (2) The radial angular contact bearing is generally subjected to a certain two-way thrust, and is mainly subjected to bearings for radial positioning and support. The rolling path generated by the inner ring of the two-way radial angular contact ball bearing is inclined by the inclined surface, and the damage is mainly caused by the defective positioning center. (3) The radial ball bearing mainly bears the bearing for radial positioning and support. The peeling of the ball pitch generated by the inner ring of the radial ball bearing. The damage caused is mainly caused by the development of the indentation caused by the impact load during the outage. (4) One-way ball bearings mainly bear bearings with axial thrust and radial positioning support. The one side of the raceway surface produced by the outer ring of the one-way radial ball bearing produces a full-circle peeling phenomenon. The damage caused is mainly caused by excessive axial load. (5) The self-aligning roller bearing mainly bears the bearing with biaxial self-aligning and radial positioning support. The inner ring of the self-aligning roller bearing is only a single-sided peeling phenomenon in the single row of the raceway surface. The damage caused is mainly caused by poor lubrication. (6) Deep groove ball bearings mainly bear bearings that have a certain axial thrust and radial positioning support. The peeling of the ball pitch generated by the inner ring raceway surface of the deep groove ball bearing. The damage caused is mainly caused by the indentation caused by excessive impact load during installation. (7) The self-aligning roller bearing mainly bears the bearing with biaxial self-aligning and radial positioning support. The inner ring of the self-aligning roller bearing is only a single-row peeling phenomenon in a single row of the raceway surface. The damage caused is mainly caused by excessive axial load. 4 Comprehensive analysis and measures to take measures 4.1 Comprehensive analysis of bearing damage is related to the power, selection, design, manufacturing and installation quality of the equipment, as well as the operation mode and maintenance, etc., often at the same time, mutual influence, judgment The reason is somewhat difficult. It is even more difficult to solve. However, there are still certain rules to follow. As long as we grasp the law of the phenomenon and the cause of the problem, there will be a solution. According to the specific problem phenomenon, sum up the experience, analyze and propose the targeted measures to solve the problem, to improve the life of the equipment, to reduce the workload and maintenance costs. 4.2 Measures According to the analysis of the cause of the problem, there are generally the following ways: (1) According to the size of the load, the design, selection and bearing type of the accounting bearing are studied again. (2) Cleaning the fuel tank during maintenance and improving the installation process and lubrication Ways, choice of oil type and other means; (3) The size of the operating load is determined by the impact force to start and stop. (4) Check the bending, pendulum and wheel sway of the shaft to improve the alignment accuracy to reduce the axial and radial impact forces. (5) Check the strength of the bearing housing and its bottom corner bolts to prevent shock fatigue damage caused by vibration. (6) Select different pairs of wheels to slow the axial and radial impact forces to improve the life of the wheels and bearings. (7) Improve the shaft end seal device, prevent the bearing from entering the water corrosion and the measures of drainage and oil change and anti-corrosion after the stop. Correct storage method for bearings
1. Keep the original packaging and do not open it arbitrarily. If the package is found to be damaged, it must be opened carefully and re-applied. 2. The relative humidity of the storage room should not exceed 60%, the temperature difference should not be too large, and the bearings placed in the original packaging can be stored for several years. Sealed bearings or bearings with a dust cover may have reduced lubrication properties of the grease filled in the bearing after prolonged storage. 3. The storage room should also be protected from vibration and shaking. Bearings not stored in the original packaging should be properly stored. It is strictly forbidden to put the bearings together with corrosive materials to prevent corrosion and pollution. 4. Large rolling bearings can only be placed flat when stored, and the sides of the inner and outer rings are preferably all supported. If it is stored upright, the inner and outer rings and rolling parts are heavier, while the inner and outer rings are relatively thin, which may cause permanent deformation.