Five points for correct installation and adjustment of low noise NTN bearings
Five points for correct installation and adjustment of low noise NTN bearings
2022年4月13日
Common problems and precautions in selecting and using Timken bearings
Common problems and precautions in selecting and using Timken bearings
2022年4月14日

How to prevent the influence of Timken imported bearing running sound on its service life

  • Needle roller bearing is a mass-produced mechanical part with strict manufacturing accuracy and high degree of technical specialization. Therefore, for the vast majority of bearing varieties that are easy to buy, it should be more cost-effective to buy than repair.
  •  In addition to economy, the repair of bearing also has its technicality, which requires the repairer to fully understand the corresponding technical requirements of bearing and the characteristics of bearing and its parts in structure, process and materials, Otherwise, it is difficult to ensure the satisfactory effect of bearing repair.

 How to prevent the influence of Timken imported bearing running sound on its service life

  • Benchmark invariant combined repair method. When repairing and adjusting the accuracy of dimension chain, according to the principle of datum coincidence, only one datum plane is selected as the datum, that is, the design datum, while all other action surfaces are repaired based on this plane. How to prevent the influence of Timken imported bearing running sound on its service life
  • This combined repair benchmark is convenient to check the accuracy and reduce the accumulated error. For example, in the repair of variable speed hydraulic coupling, the bearing body is often used as the benchmark.
  • Datum transformation combined repair method. Sometimes the deformation of the design datum is too large to be used, so it is necessary to select some other planes as the datum and re integrate the dimension chain at the same time.
  •  For example, if the deformation of the bearing body is too large, the bearing body shall be reprocessed and corrected based on the rotating assembly, and then the assembly dimension chain shall be adjusted according to the size of the reprocessed bearing body. How to prevent the influence of Timken imported bearing running sound on its service life
  • The method of repairing the adjusting ring shall be adopted to detect and repair according to the arrangement order of the dimension chain, so as to control the accuracy of the closed ring. How to prevent the influence of Timken imported bearing running sound on its service life
  • Another function of Timken bearing sealing device is to prevent grease leakage from bearing components. If there is oil leakage, it will quickly destroy the normal lubrication of the bearing and burn out the bearing due to fever.How to prevent the influence of Timken imported bearing running sound on its service life
  •  In addition, the poor sealing device will not only cause spreading due to oil leakage, but also pollute mechanical equipment and processed products. Therefore, in order to make the machine operate normally, the bearing must have a good sealing device.How to prevent the influence of Timken imported bearing running sound on its service life
  • When selecting the type of Timken bearing sealing device, the following factors shall be considered:How to prevent the influence of Timken imported bearing running sound on its service life
  • Working ring of Timken bearing.How to prevent the influence of Timken imported bearing running sound on its service life
How to prevent the influence of Timken imported bearing running sound on its service life
 
  • Structural features of Timken bearing components.
  • Speed of Timken bearing (circumferential speed of bearing).
  • Type of lubricant (oil or grease) for Timken bearings.How to prevent the influence of Timken imported bearing running sound on its service life
  • Operating temperature of Timken bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  • As soon as the outer spherical bearing rotates, the raceway surface of the inner ring and the outer ring is in rolling contact with the rolling element, so the running track is a dark surface. The running track attached to the raceway surface is not abnormal, so the load conditions can be known. Therefore, please pay close attention and observe the running track of the raceway surface when disassembling Timken bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  • If you carefully observe the running track, you will know that it only bears radial load, large axial load, moment load, or extreme uneven rigidity on the bearing housing. It can be checked whether the unexpected load is added to the bearing and whether the installation error is too large, which will become a clue to investigate the damage cause of the outer spherical bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  • Lubrication is very important, not only for Timken bearings, but also for all bearings. However, please note that the bearing should not add too much grease. Then it’s time to change the lubricant of the bearing. 
  • After draining the old engine oil, if possible, the bearings lubricated with engine oil should be filled with fresh engine oil and let the machine rotate at low speed for a few minutes. How to prevent the influence of Timken imported bearing running sound on its service life
  • Make the oil collect residual pollutants as much as possible, and then drain the oil. When replacing the grease of the bearing lubricated with grease, the Joe remover used should avoid the contact of cotton with any part of the outer spherical bearing. Because these residual fibers may wedge between rolling parts and cause damage, especially in the application of small bearings.How to prevent the influence of Timken imported bearing running sound on its service life
  • When inspecting the bearing, never expose the bearing to pollutants or moisture. If the work is interrupted, the machine shall be covered with oil paper, plastic sheet or similar materials. If it is possible to clean the naked bearing without disassembly, clean it with a brush coated with petroleum solvent, and then wipe it dry with a piece of lint free cloth or blow it dry with compressed air (be careful not to start the rotation of the bearing assembly). How to prevent the influence of Timken imported bearing running sound on its service life
  • Use a small mirror and a probe similar to that used by dentists to check the track surface, retainer and beads of the bearing. Do not clean Timken bearings with encrypted cover or dust-proof; Just wipe the outer surface. If the bearing is damaged, it needs to be replaced.
  •  It is much more economical to replace the bearing during the regular shutdown and maintenance period than the loss of sudden shutdown due to the damage of the array bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  • Contact fatigue failure refers to the failure of bearing working surface caused by alternating stress. Contact fatigue spalling occurs on the working surface of the bearing and is often accompanied by fatigue cracks.
  •  It first occurs from the large alternating shear stress below the contact surface, and then extends to the surface to form different spalling shapes, such as pitting or pitting spalling, which is called shallow spalling.How to prevent the influence of Timken imported bearing running sound on its service life
  • Wear failure refers to the failure caused by the continuous wear of the metal on the working surface caused by the relative sliding friction between the surfaces. Continuous wear will cause gradual damage to bearing parts, and eventually lead to the loss of bearing dimensional accuracy and other related problems. 
  • Wear may affect the change of shape, the increase of fit clearance and the change of working surface morphology, may affect the lubricant or make it polluted to a certain extent, resulting in the complete loss of lubrication function, so that the outer spherical bearing loses the rotation accuracy and even can not operate normally. 
  • Wear failure is one of the common failure modes of all kinds of Timken bearings. According to the wear form, it can be divided into common abrasive wear and adhesive wear.How to prevent the influence of Timken imported bearing running sound on its service life
  • It is the running track of the outer ring when the cylindrical roller bearing used in the rotating load of the inner ring is correctly loaded with radial load.
  • It is a running track with relatively inclined inner ring and outer ring and large deflection of shaft. The running track of raceway surface produces intensity in its longitudinal direction. At the outlet of load ring, the running track is inclined, and the double row tapered roller bearing rotates the inner ring.
  • Indicates the running track of the outer ring when only radial load is borne. L represents the trajectory under axial load only. When the inner ring and outer ring are relatively inclined and only bear radial load, their running track deviates from the two rows of track surfaces by 180. Location of the (m).How to prevent the influence of Timken imported bearing running sound on its service life
  • There may be many factors affecting the service life of Timken imported bearings. The possible factors and internal friction sound have been further explained. The main factors used for adjustment are installation, use and maintenance, maintenance and repair, which meet the technical requirements. 
  • According to the technical requirements for the installation, use, maintenance and maintenance of Timken imported bearings, the contact load, speed and lubrication status of the operating bearings are monitored and inspected. The direct cause of the abnormality is found and adjusted back to normal.
  • Installation conditions, one of the factors used for bearings is the load-bearing force that often causes the change of state between various parts of the incorrect installation package, the primary factor of abnormal state of bearing working temperature, vibration, noise, gradual progress, and the quality of raw materials has been improved.How to prevent the influence of Timken imported bearing running sound on its service life
  •  The proportion of raw material quality factor in bearing fault analysis has decreased significantly, but it is still one of the main factors of bearing failure.
  • Strictly inspect the raw materials of steel wire to prevent the raw materials with martensitic structure, decarburization, rough surface, surface transverse lines, cracks and other defects from entering the drawing process; Or after pretreatment, the material properties are improved before processing.
  • Prevent and improve the poor microstructure defects of the workpiece, such as coarse flake pearlite, reticular ferrite, etc.
  • Strictly control the metallurgical quality of NSK bearing steel wire, prevent the blank containing non-metallic inclusions and folding defects from entering the processing process, and avoid brittle fracture failure of steel wire parts.How to prevent the influence of Timken imported bearing running sound on its service life
  • The steel wire with element segregation found in the inspection of raw materials can be subject to preliminary heat treatment to eliminate defects and improve the structure. If normalizing treatment is adopted in a protective atmosphere, the harm of segregation can be reduced.How to prevent the influence of Timken imported bearing running sound on its service life
  • Whether the selection is appropriate or not is still a bearing fault analysis that must be considered. Bearing manufacturing will be adjusted and restored to normal through forging, heat treatment, turning and lubrication conditions to monitor and check the direct causes of abnormalities. The installation condition is one of the factors for using the bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  •  It is the primary factor of the bearing capacity that often causes the state change between various parts of the incorrect installation package. In the abnormal operation state and the early termination of the inner life, the main factors refer to the structural design, high-quality manufacturing technology and materials. 
  • There are three factors that determine the quality of the bearing.How to prevent the influence of Timken imported bearing running sound on its service life
  • Timken imported bearings are superior. Even if the shape becomes a low buzzing sound, there will be knocking noise when injured. This noise will collide and diverge according to the speed of Timken imported bearings.How to prevent the influence of Timken imported bearing running sound on its service life
  • If there is intermittent noise, it is through. If sharp’s hissing, squeaking and other sounds do not follow the rules, Timken imported bearings that often perform poorly will reveal or even reverse the situation.How to prevent the influence of Timken imported bearing running sound on its service life
  • According to the moving direction, it can be divided into radial clearance and axial clearance. The measurement of the radial clearance of the whole set of bearings is not easy. The measuring force causes the elastic deformation of the ferrule and the rolling element itself and its contact. How to prevent the influence of Timken imported bearing running sound on its service life
  • The amount of deformation is a multi factor causing the measurement error, which is related to the measuring force, the contact state and the position of the rolling element. The rotation flexibility of Japanese NTN bearings is generally checked at the horizontal position.How to prevent the influence of Timken imported bearing running sound on its service life
  •  Usually fix the inner ring (or hold the inner ring by hand) and rotate the outer ring by hand to check whether there is abnormal sound and blockage during bearing rotation. How to prevent the influence of Timken imported bearing running sound on its service life
  • Due to different structural types and sizes of bearings, there should be different requirements for their rotation flexibility. For example, single row centripetal ball bearings and single row centripetal thrust ball bearings are relatively light when rotating due to the small contact area between the rolling element and the ferrule, 
  • while double row centripetal spherical bearings and thrust roller bearings are less light when checking their rotation flexibility due to the large contact area between the rolling element and the raceway and the small weight of the outer ring. For extra large bearings, there should be no jamming when rotating them, and the rotating sound is generally not checked.
  •  For tapered hole bearing, the following methods can be used to supplement and check the rotation flexibility of the bearing. The specific operations are as follows: press the tapered hole bearing into the mandrel until a certain radial preload is added.How to prevent the influence of Timken imported bearing running sound on its service life
  •  Under this preload, when a ferrule rotates, the rolling element should rotate. If the rolling element slides instead of rotates, it means that there are too many geometric defects of the ferrule or the size of the rolling element is uneven, and the rotation flexibility of the bearing is poor.How to prevent the influence of Timken imported bearing running sound on its service life
  • In the case of close fit between the bearing ring and the bearing seat or transmission shaft, the bearing ring may be deformed by matching with the shape of adjacent components. If deformation occurs, vibration may occur during operation. Therefore, it is important to machine the bearing pedestal and drive shaft to the required tolerances.How to prevent the influence of Timken imported bearing running sound on its service life
  • The bearing is excited by the change of the number of loaded rolling elements. When a radial load is loaded on a bearing, the number of loaded rolling elements will change slightly during operation, that is to say, it will cause the shift of load direction. In this case, it is inevitable to reduce the vibration of the roller by preloading the roller (but it is not applicable to all rolling bearings).How to prevent the influence of Timken imported bearing running sound on its service life
  • The bearing is partially damaged. A small number of bearing raceways and rolling elements may be damaged due to incorrect operation or installation. In operation, rolling damaged bearing components will produce specific vibration frequencies. Vibration frequency analysis can identify damaged Japanese NTN bearing components.
  • As we all know, NTN imported bearings are precision parts and require considerable caution in use, that is, high-performance bearings are used. If they are not used properly, they can not achieve the expected performance effect, and it is easy to damage NTN imported bearings. How to prevent the influence of Timken imported bearing running sound on its service life
  • Most bearings are broken for many reasons – exceeding the original estimated load, ineffective sealing, too small NTN inlet bearing clearance caused by too tight fit, etc. Any of these factors has its special damage type and will leave special damage traces.How to prevent the influence of Timken imported bearing running sound on its service life
  • Therefore, by examining the damaged bearing, we can find the possible causes in most cases. Generally speaking, one third of the NTN imported bearing damage is due to fatigue damage, the other one third is due to poor lubrication, and the other one third is due to pollutants entering the bearing or improper installation and treatment.
  • How to protect it and prolong its service life, the following matters should be paid attention to when using the bearing:How to prevent the influence of Timken imported bearing running sound on its service life
  • The installation and adjustment of low-noise NTN bearing can also follow the grouping method of long-life bearing, so that the matching interference is more consistent, and the clearance of NTN bearing is also more consistent. How to prevent the influence of Timken imported bearing running sound on its service life
  • It is hoped that the matching interference will take a smaller value within the possible range, so as to ensure that the deformation of NTN bearing raceway is small, and the noise caused by the passage of rolling element will be reduced.How to prevent the influence of Timken imported bearing running sound on its service life
  • The clearance has a great influence on the noise. The ideal state is that when the NTN bearing is in the high temperature state of operation, the clearance value is just zero. The methods to judge the excessive clearance are: the axial displacement of the bearing in the static state, the reciprocating amplitude is large, and a large and turbid noise is emitted during operation.How to prevent the influence of Timken imported bearing running sound on its service life
  • If there is an annoying shriek during operation, it indicates that the preload of NTN bearing is too large and the bearing has too large pre interference. The preload should be slightly relaxed. If the clearance is too large, the two bearing rings can be slightly offset along the axial direction:
  •  it not only reduces the clearance, but also increases the axial rigidity and reduces the bearing noise.How to prevent the influence of Timken imported bearing running sound on its service life.How to prevent the influence of Timken imported bearing running sound on its service life
  • When the rolling element enters the no-load area, it will slip or move left and right, which will not only increase the noise, but also cause wear. Small clearance and large axial stiffness can eliminate this phenomenon. However, the clearance should not be too small, so as not to cause excessive temperature and shorten service life.How to prevent the influence of Timken imported bearing running sound on its service life
  • Sometimes, due to the large working temperature range of the main engine or the large dispersion of the size between the shaft and the bearing seat hole, it is impossible to obtain a more appropriate clearance at one time. In this case, the elastic constant pressure preloading method can be adopted for the outer ring of NTN bearing.How to prevent the influence of Timken imported bearing running sound on its service life