Common faults and necessary remedial measures of Timken thrust ball bearing
Common faults and necessary remedial measures of Timken thrust ball bearing
2022年4月11日
Precautions for prolonging the service life of IKO one-way bearing
2022年4月12日

Causes of universal joint bearing failure

  • Although the bearing is metal, it will also be damaged. No matter what hard material it is, it will be damaged, but the degree of damage is different. We all know that the bearing is of good quality and made of good steel. Steel is a very solid material, but it will also be damaged. Causes of universal joint bearing failure

Causes of universal joint bearing failure

  • The rotary table bearing runs in the machine every day, and it is easy to damage the bearing due to constant friction, so we should also prevent the damage of the bearing, We should maintain the bearing well and do not use the bearing indiscriminately, which will cause unnecessary losses to ourselves.Causes of universal joint bearing failure
  • Timken bearing is to ensure that it can produce excessive deformation during installation. It is also necessary to do from these aspects. There are many things to do for the bearing. Here are the effects of those aspects that need to be paid attention to.
  • The roundness of shaft and seat hole and the perpendicularity of retaining shoulder shall be required according to the corresponding accuracy of bearing.
  • It is necessary to accurately calculate the interference amount of the rotating ferrule and the appropriate amount of the fixed ferrule. The burning interference of rotating ferrule should also be small within the possible range. Causes of universal joint bearing failure
  • As long as the influence of thermal expansion under working temperature and centrifugal force under high speed are ensured, the creep or sliding of tight fitting surface will not be caused. According to the working load and bearing size, the fixed ring selects a very small clearance fit or interference fit. Too loose or too tight is not conducive to maintaining the original accurate shape.Causes of universal joint bearing failure
  • If the bearing operates at high speed and the working temperature is high, special attention should be paid to the matching of the rotating ring not to be too loose to prevent eccentric vibration, and the matching of the fixed ring should not have clearance to prevent the ring from deforming and exciting vibration under load.Causes of universal joint bearing failure
  • 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.Causes of universal joint bearing failure
Causes of universal joint bearing failure
  • The main shaft with paired double angular contact ball bearings has light half load. If the fit interference is too large, the internal axial preload will be significantly too large, resulting in adverse effects. The spindle with double row short cylindrical roller bearing and the spindle with rotary table bearing have relatively large load, so their fitting interference is also relatively large.Causes of universal joint bearing failure
  • From the perspective of rotation, Timken bearing should pay attention to the above situations in terms of configuration, but whether the temperature is stable or not should be considered. The main aspect is how the rotary table bearing should cooperate with its device effect.Causes of universal joint bearing failure
  • Speed and temperature rise:Causes of universal joint bearing failure
  • With the development of science and technology, the rotating speed of machine tool spindle is higher and higher, and the speed range is larger and larger. Therefore, the requirements for the stability of bearing high-speed operation are higher and higher. The temperature rise of machine tool spindle bearing is an important factor to limit the bearing speed. Generally, the correct selection of non-standard bearing type, tolerance grade, configuration mode, clearance (preload), lubricant and lubrication mode can improve the high-speed performance of rolling bearing to a certain extent.Causes of universal joint bearing failure
  • Technical requirements for Timken bearing of main shaft
  • Service life and bearing capacity:Causes of universal joint bearing failure
  • For general machine tools, the service life of the spindle assembly mainly refers to the service life of maintaining the spindle accuracy. Therefore, the accuracy maintenance performance of the bearing is required to meet the requirements of the service life of the spindle assembly. For heavy machine tools or power cutting machine tools, the bearing capacity of non-standard bearings should be considered first.Causes of universal joint bearing failure
  • Rolling bearings make precision parts, so it is required to be cautious when using them. Since high-performance bearings are used, if they are not used properly, they can not achieve the expected performance effect. Therefore, the following matters should be paid attention to when using bearings:Causes of universal joint bearing failure
  • Keep non-standard bearings and their surroundings clean. Even if the small dust invisible to the naked eye enters the bearing, it will increase the wear, vibration and noise of the bearing.Causes of universal joint bearing failure
  • When using and installing, it shall be careful. It is not allowed to punch with force, directly knock the bearing with a hammer, and transfer pressure through the rolling body.
  • Use proper and accurate installation tools, try to use special tools, and try to avoid using cloth and short fiber.Causes of universal joint bearing failure
  • To prevent Timken bearing from rusting, when taking the bearing directly by hand, fully wash the sweat from your hands and apply high-quality mineral oil
  • The inner diameter and outer diameter of rolling bearings are manufactured according to standard tolerances. The fit tightness of bearing inner ring and shaft, outer ring and seat hole can only be realized by controlling the tolerance of journal and seat hole. The matching of non-standard bearing inner ring and shaft adopts base hole system, and the matching of bearing outer ring and seat hole adopts machine shaft system.Causes of universal joint bearing failure
  • To correctly select the fit, you must know the actual load conditions, working temperature and other requirements of Timken bearing, which is actually very difficult. Therefore, in most cases, the matching is selected according to the use of fine grinding.Causes of universal joint bearing failure
  • The win-win amount between the ferrule and the shaft or shell depends on the load. The heavier load adopts the larger win-win amount, and the lighter load adopts the smaller win-win amount.Causes of universal joint bearing failure
  • According to the formation mechanism of grinding metamorphic layer on the working surface of Timken bearing, the main factors affecting grinding metamorphic layer are grinding heat and grinding force. Next, analyze the causes of universal joint bearing failure.Causes of universal joint bearing failure
  • Main purpose of preloading: the main purpose and representative examples of preloading can be proved by giving some examples:Causes of universal joint bearing failure
  • While correctly determining the position of the radial direction and axial direction of the shaft, restrain the runout of the shaft.Causes of universal joint bearing failure
  • Improve the rigidity of the bearing. The spindle of the machine tool is used as the bearing, and the pinion of the differential mechanism is used as the imported bearing.Causes of universal joint bearing failure
  • Prevent axial vibration and abnormal sound caused by resonance. Bearings for small motors.Causes of universal joint bearing failure
  • For the centripetal bearing under combined load, due to the increase of the number of rolling elements under load, the increase of friction resistance, the increase of fever, the deterioration of lubrication and cooling conditions, and the increase of force acting on the cage, it is necessary to adjust the limit speed of universal joint bearing by multiplying a reduction factor F2 according to Timken bearing type and load angle.Causes of universal joint bearing failure.Causes of universal joint bearing failure
  • If the limit speed of the selected bearing cannot meet the application requirements, some improvement techniques and methods can be adopted to make progress, so as to meet the requirements. Such as increasing the tolerance difference of Timken bearing; Properly increase the clearance; Causes of universal joint bearing failure
  • Use special materials and improve the structure of the persistence frame; Change lubrication methods, such as oil-gas, oil mist and jet lubrication; Improved cooling conditions.Causes of universal joint bearing failure
  • In the case of premature failure of all Timken bearings, about 16% are caused by improper or incorrect installation. Various applications may require machinery, proper thermal or hydraulic devices and effective installation of linear bearings.Causes of universal joint bearing failure 
  • Choosing the appropriate installation method of the application will help you prolong the service life of the bearing and reduce the cost caused by premature failure and potential damage of the bearing.Causes of universal joint bearing failure
  • The bearings are usually heated in an oil bath before installation. However, this method may pollute the bearing and cause premature bearing failure. Induction heating is a common heating method. Because of its controllability, the efficiency and of bearing are very high. Causes of universal joint bearing failure
  • Application development standard of Timken bearing induction heater. The linear bearing induction heater has many functions to help prevent damage to the bearing during heating.Causes of universal joint bearing failure
  • In fact, if each specific use, a sufficient number of bearing life tests have been taken to verify whether it is suitable for the economic time and labor of the selected bearing. Therefore, the bearing life test method is necessary or important. In most cases, before use, a standard calculation method is used to estimate the life of Timken bearing life, which has a sufficient reliability level.Causes of universal joint bearing failure
  • The metallurgical quality of Timken bearing material was once the main factor affecting the early failure of rotating bearing. With the progress of metallurgical skills (such as vacuum degassing of bearing steel), the quality of raw materials has been improved.Causes of universal joint bearing failure
  •  The proportion of raw material quality factor in bearing failure description has obviously decreased, but it is still one of the main influencing factors of bearing failure. Whether the material selection is appropriate is still the factor that must be considered in the failure description of linear bearing.Causes of universal joint bearing failure
  • In addition, the working conditions of the monitored bearings have the plan of bearing effect in the repair progress of the bank, which can get twice the result with half the effort. According to a reasonable process, efficient equipment and things for maintenance, and with the help of professionals, the bearing factory will contribute to economic development.Causes of universal joint bearing failure
  • Timken bearing metal corrosion and rust are the key points of sweaty hands, accounting for the vast majority of metal corrosion, which can not be avoided in many cases. Hand sweat will cause corrosion of linear bearings, mainly sweat on its membrane sweat contact surface. Electrochemical reaction and interaction will lead to corrosion, but it can be avoided, such as gloves, professional tools such as picking up parts.Causes of universal joint bearing failure
  • The work of grease is separated from the ball and used with the inner and outer raceway oil layer. The viscosity of oil is used. It is pasted on the ball and raceway surface, and separated from the inner and outer raceway and metal interface ball, which reduces the wear of metal surface, prevents air and moisture from corroding metal, reduces vibration and noise, and makes the linear bearing rotate smoothly.Causes of universal joint bearing failure
  • Timken bearing shows the characteristics of late failure. The time from the occurrence of serious failure (generally bearing damage, such as shaft holding, burn, sand frame crack, raceway, bead wear, etc.) is mostly less than one week.Causes of universal joint bearing failure
  •  The larger the equipment capacity, the faster the speed, and the shorter the interval. Therefore, in the actual rolling bearing fault diagnosis, once the late fault characteristics are found, the fault of linear bearing should be determined and the maintenance should be arranged as soon as possible.Causes of universal joint bearing failure.
  • treatment.
  •  Causes of universal joint bearing failure
  • How to protect it and prolong its service life, the following matters should be paid attention to when using the bearing:

 Causes of universal joint bearing failure

  • 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. 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.
  •  Causes of universal joint bearing failure
  • 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.
  • 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.
  • 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.
  • 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.
  • Koyo imported bearing, in most cases, working state: use appropriate clearance. According to different uses, and in the assembly bearing, the bearing is advanced to make the internal stress and make the negative bearing clearance used. This method is called using preload. More suitable, such as angular contact ball bearings, tapered roller bearings, two family bearings, bearing clearance, can be adjusted.
  • Main purpose of preloading: the main purpose of preloading can be proved by some representative examples:
  • In the correct direction and radial position, the axial direction determines the shaft and suppresses the runout of the shaft.
  • Increase the rigidity of the bearing. Machine tool spindle bearing, bicycle and small agent bearing, gear differential.
  • To prevent the axial direction of vibration and resonance of different sounds. Small motor bearings.
  • Suppresses scrolling, rotating slides, sliding and rotating revolution slides. High speed rotating center thrust bearing, thrust ball bearing.
  • Ring and keep rolling in the correct position. Thrust ball bearing, thrust spherical roller bearing, and horizontal shaft.
  • Preloading method: the pre positioning of load is the preloading method that the relative position of Koyo imported bearing shaft will not change in use. Here is an example
  • In order to implement the difference before the adjustment of the width between preloads or the fastening method after the axial clearance of bearings.
  • Adjust the size of the pad, gasket and bearing preload to make way.
  • The method adopted after tightening the screw and nut clearance with adjustable shaft direction. In this case, adjust the friction torque on the hand side with an appropriate preload to determine the start.
  • The so-called constant pressure preload is the use of coil springs and Belleville springs to give the load-bearing of appropriate preparation methods. When in use, even if the relative position of the Koyo inlet bearing changes, the preloading method. When in use, it will even change its relative position, and the preload can be maintained at a certain level.
  • 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. Make the oil collect residual pollutants as much as possible, and then drain the oil. Note: the engine oil is filtered before use.Causes of universal joint bearing failure
  • When replacing the grease of the bearing lubricated with grease, the Joe remover used shall avoid the contact of cotton with any part of the bearing. Because these residual fibers may wedge between rolling parts and cause damage, especially in the application of small bearings.Causes of universal joint bearing failure
  • Wen inspecting Koyo imported bearings, never expose the bearings to pollutants or moisture. If the work is interrupted, cover the machine with oil paper, plastic sheet or similar materials.Causes of universal joint bearing failure
  • Tile surface corrosion: abnormal concentration of non-ferrous metal elements is found by spectral analysis; Submicron wear particles with many non-ferrous metal components appear in ferrography; The water content and acid value of lubricating oil exceed the standard.Causes of universal joint bearing failure
  • Journal surface strain: there are ferrous cutting abrasive particles or black oxide particles in the ferrogram, and there is tempering color on the metal surface.
  • Journal surface corrosion: the spectral analysis found that the concentration of iron was abnormal. There were many submicron particles of iron in the ferrogram, and the water content or acid value of lubricating oil exceeded the standard.Causes of universal joint bearing failure
  •  Causes of universal joint bearing failure
  • Surface strain: cutting abrasive particles are found in the Ferrograph, and the abrasive particles are composed of non-ferrous metals.Causes of universal joint bearing failure
  •  Causes of universal joint bearing failure
  • Fretting wear of tile back: abnormal iron concentration is found by spectral analysis. There are many iron components, submicron wear particles, abnormal moisture and acid value of lubricating oil in the ferrogram.
Causes of universal joint bearing failure