Analysis on the basic steps of maintenance and overhaul of NTN spherical plain bearings
Analysis on the basic steps of maintenance and overhaul of NTN spherical plain bearings
2022年5月29日
Judging the service life of fag needle roller bearing from its running sound
Judging the service life of fag needle roller bearing from its running sound
2022年5月31日

Failure reason of ina imported bearing

Influence on vibration and noise of ina imported bearing

  • The cleanliness of INA Bearing has a great impact on the service life of bearing. Ina bearing has carried out special tests for this purpose, and the result is that the difference is several times or even dozens of times. The higher the cleanliness of the bearing, the longer the service life. 
  • The tests of others show that the lubricating oil with different cleanliness has a great impact on the service life of the ball bearing. Therefore, improving the cleanliness of the lubricating oil can prolong the service life of the bearing. In addition, if the dirt particles in the lubricating oil are controlled below 10um, the service life of the bearing will increase several times.
  • The test results of INA Bearing Test Center show that the cleanliness seriously affects the vibration level of the bearing, especially in the high frequency band. The bearing with high cleanliness has low vibration speed, especially in high frequency band.
  • The influence of dust in INA Bearing Grease on noise has been tested. It is proved that the more dust, the greater the noise.Failure reason of ina imported bearing
  • The decrease of INA Bearing cleanliness will not only affect the formation of lubricating oil film, but also cause the deterioration of lubricating grease and accelerate its aging, thus affecting the decline of lubricating performance of lubricating grease. In order to ensure the working condition of NTN bearing, it is necessary to avoid damage as much as possible. What should we do?Failure reason of ina imported bearing
  • Generally, if the bearing is used correctly, it can be used until the fatigue life is reached. However, there will be accidental and premature damage, which can not be resistant to use. This early damage, as opposed to fatigue life, is called the quality service limit of failure or accident. Most of them are caused by careless installation, use and lubrication, foreign matters invading from the outside, and insufficient research on the thermal effects of shafts and shells.Failure reason of ina imported bearing
  • As for the damage state of NTN bearing, for example, the clamping damage of the ring retaining edge of roller bearing can be considered as the reason. These reasons can also coincide with insufficient lubricant, unsuitable, defects of oil supply and drainage structure, intrusion of foreign matters, bearing installation error and excessive deflection of shaft.Failure reason of ina imported bearing
  • Therefore, only investigating the bearing damage, it is difficult to know the real cause of the damage. However, if you know the use machinery, service conditions, the structure around the bearing, the situation before and after the accident, and combined with the damage state of the bearing and several causes, you can prevent the recurrence of similar accidents. The structural design, manufacturing process and material quality of ina imported bearings are analyzed.Failure reason of ina imported bearing
  • Ina imported bearing will have a long service life only if its structure design is reasonable and it is progressiveness. The manufacturing of bearings generally goes through multiple processing processes such as forging, heat treatment, turning, grinding and assembly. The rationality, progressiveness and stability of each processing technology will also affect the service life of the bearing. 
  • Among them, the heat treatment and grinding processes that affect the quality of finished bearings are often more directly related to the failure of bearings. In recent years, the research on the metamorphic layer on the working surface of bearing shows that the grinding process is closely related to the surface quality of bearing.Failure reason of ina imported bearing
  • The metallurgical quality of ina imported bearing materials was once the main factor affecting the early failure of rolling bearings. With the progress of Metallurgical Technology (such as vacuum degassing of bearing steel), the quality of raw materials has been improved. Failure reason of ina imported bearing
  • The proportion of raw material quality factor in bearing failure analysis has decreased significantly, but it is still one of the main influencing factors of bearing failure. Proper material selection is still a factor that must be considered in bearing failure analysis.Failure reason of ina imported bearing
  • The main task of ina imported bearing failure analysis is to find out the main factors causing bearing failure according to a large number of background materials, analysis data and failure forms, so as to put forward targeted improvement measures, prolong the service life of the bearing and avoid sudden early failure of the bearing.Failure reason of ina imported bearing
Failure reason of ina imported bearing

Effect on lubrication performance   ina imported bearing

  • In terms of its function, the bearing should be support, that is, it is literally used to support the bearing, but this is only part of its function. The essence of support is to be able to bear radial load. It can also be understood that it is used to fix the shaft.Failure reason of ina imported bearing
  •  It is to fix the shaft so that it can only rotate and control its axial and radial movement. The consequence of motor without bearing is that it can’t work at all. Because the shaft may move in any direction, and the motor requires that the shaft can only rotate. Theoretically speaking, it is impossible to realize the function of transmission. Failure reason of ina imported bearing
  • Moreover, the bearing will also affect the transmission. In order to reduce this impact, good lubrication must be achieved on the bearing of high-speed shaft. Some bearings already have lubrication, which is called pre lubricated bearing, while most bearings must have lubricating oil. When running at high speed, friction will not only increase energy consumption, but also easily damage the bearing.Failure reason of ina imported bearing

What effect does ina imported bearing lubricating 

  • Whether it is a rolling bearing or a sliding bearing, when the shaft rotates, the rotating part and the stationary part cannot be in direct contact, otherwise it will be damaged due to friction. In order to prevent friction between dynamic and static parts, lubricant must be added. The effect of lubricant on bearing is mainly manifested in three aspects: lubrication, cooling and cleaning.
  • Bearings can be divided into many kinds, rolling bearings, radial bearings, ball bearings, thrust bearings and so on. In terms of its function, it should be support, that is, it is literally used to support the bearing, but this is only a part of its function. The essence of support is to be able to bear radial load. It can also be understood that it is used to fix the shaft. It is to fix the shaft so that it can only rotate and control its axial and radial movement.Failure reason of ina imported bearing
  • What is the function of clutch release bearing?Failure reason of ina imported bearing
  • Clutch release bearing is a kind of thrust bearing (commonly known as clutch spring disk). Its function is to move the pressing plate or driving plate bearing the spring thrust to the clutch housing when stepping down the clutch pedal, that is, when stepping down the clutch pedal, tilt the release lever to overcome the spring thrust of the pressing plate, so as to complete the separation of the clutch.Failure reason of ina imported bearing
  • The release lever of the clutch rotates with the pressing plate, while the operating mechanism linked with the clutch pedal cannot rotate. In order to adapt to the different motion conditions between the two, thrust bearings are used to reduce friction and wear.Failure reason of ina imported bearing
  • If the release bearing loses its sliding function due to lack of oil, it will not only produce abnormal noise, but also aggravate the stress point of the release rod, and the effective range of the clutch pedal starting pressing plate will be smaller and smaller. When the clutch plate is not completely separated from the pressure plate, the shift will produce abnormal noise. The wear of the release rod will cause uneven or incomplete start of the pressure plate, and the drive and driven are involved with each other, resulting in failure to shift.Failure reason of ina imported bearing
  • Rolling bearings can be divided into two categories according to the types of rolling elements: ball bearings (ball bearings), whose rolling elements are balls; Roller bearing (roller bearing), whose rolling element is cylindrical.Failure reason of ina imported bearing
  • Rolling bearings can be divided into the following categories according to the load action direction they can bear:
  • Radial bearing can only bear radial load (such as radial short cylindrical roller bearing), or it can bear small axial load (such as radial ball bearing) while bearing radial load.Failure reason of ina imported bearing
  • The radial thrust bearing can bear the combined radial and axial load, and may be dominated by radial load or axial load.Failure reason of ina imported bearing
  • Thrust radial bearing can bear axial load, but it can also bear axial load and small radial load at the same time.
  • Thrust bearing can only bear axial load.Failure reason of ina imported bearing
  • According to the direction of load and the type of rolling element, rolling bearings are divided into ten types;

Classification by ina imported bearing

  • Rolling bearing is a kind of precision mechanical element that changes the sliding friction between the running shaft and the shaft seat into rolling friction, so as to reduce the friction loss. It is composed of outer ring, inner ring and rolling cage. Rolling bearing is generally composed of inner ring, outer ring, rolling element and cage. The function of inner ring is to match with the shaft and rotate with the shaft; Failure reason of ina imported bearing
  • The function of the outer ring is to cooperate with the bearing seat and play a supporting role; The rolling element is evenly distributed between the inner ring and the outer ring with the help of the cage. Its shape, size and quantity directly affect the service performance and service life of the rolling bearing; Failure reason of ina imported bearing
  • The cage can make the rolling elements evenly distributed, prevent the rolling elements from falling off, and the rolling elements rotate for lubrication; Among them, there is no retainer design, full loaded roller bearing, which is also widely used
  • Bearings are divided into rolling bearings according to the load direction or nominal contact angle they can bear. Radial bearings are mainly used to bear radial load, and their nominal contact angle ranges from 0 to 45 degrees. According to different nominal contact angles, it is divided into radial contact bearing – radial bearing with nominal contact angle of 0: radial angular contact bearing – radial bearing with nominal contact angle greater than 0 to 45.Failure reason of ina imported bearing
  • Thrust bearing —- rolling bearing mainly used to bear axial load, and its nominal contact angle is greater than 45 to 90. According to different nominal contact angles, it is divided into axial contact bearing – thrust bearing with nominal contact angle of 90: thrust angle contact bearing – thrust bearing with nominal contact angle of 5 but less than 90.Failure reason of ina imported bearing

The oil bath of ina imported bearing is smooth. 

  • The oil bath is a common smooth way in the bearing, which is suitable for the smooth of low and medium speed bearings. Partially immerse the bearing in the groove, and the smooth oil is brought up by the rotating turbocharged bearing parts, and then flows back to the oil groove. The oil level should be slightly lower than the center of the low dynamic projectile.Failure reason of ina imported bearing
  • The oil dripping of the bearing is smooth. The oil dripping is smooth. It is suitable for the bearing components that need to supply smooth oil quantitatively. The oil dripping amount is appropriate to drop once every 3-8 seconds. Excessive oil will cause the bearing temperature to increase.Failure reason of ina imported bearing
  • The circulating oil of the bearing is smooth. The filtered oil is delivered to the bearing parts by the oil pump. The smooth oil after passing through the bearing is filtered and cooled before use. Since the circulating oil can take away certain heat and cool the bearing, this method is applied to turbocharged bearing components with high speed.Failure reason of ina imported bearing
  • The spray of the bearing is smooth. The dry shrinking air is mixed with the smooth oil through the spray to cause oil mist. In the radial bearing, the air flow can effectively cool the bearing and avoid the invasion of impurities. This method is suitable for the smoothing of high-speed and low-temperature turbocharged bearing components.Failure reason of ina imported bearing
  • The radiation of the bearing is smooth. Use the oil pump to shoot the low-pressure oil into the bearing through the nozzle, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. When the bearing rotates at a high speed, the moving bullet body and the maintenance frame also cause air flow around at a fairly high rotation speed. Failure reason of ina imported bearing
  • It is difficult to send the smooth oil to the turbocharged bearing in an individual smooth way. At this time, the smooth oil must be sprayed into the bearing in the way of low-pressure radiation, and the position of the nozzle should be placed between the inner ring and the center of the maintenance frame.Failure reason of ina imported bearing
  • Generally speaking, the rolling bearing itself does not produce noise. The “bearing noise” usually felt is actually the sound effect of vibration between the bearing and the surrounding structure directly or indirectly. This is why many times noise problems can be regarded as vibration problems involving the whole bearing application.Failure reason of ina imported bearing
  • Excitation caused 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, which causes the deviation of the load direction. The resulting vibration is inevitable, but can be reduced by axial preloading, which is applied to all rolling elements (not applicable to cylindrical roller bearings).Failure reason of ina imported bearing

Local damage: of ina imported bearing

  • a small number of bearing raceways and rolling elements may be damaged due to incorrect operation or installation. During operation, rolling over damaged bearing parts will produce specific vibration frequency. Vibration frequency analysis can identify damaged bearing components. This principle has been applied to condition monitoring equipment to detect bearing damage. To calculate the bearing frequency, refer to the calculation program “bearing frequency”.Failure reason of ina imported bearing
  • Accuracy of relevant parts: when the bearing ring is closely matched with the bearing seat or transmission shaft, the bearing ring may be deformed by matching with the shape of adjacent parts. If deformation occurs, vibration may occur during operation.Failure reason of ina imported bearing
  • Pollutants: if operating in a polluted environment, impurities may enter the bearing and be rolled by the rolling element. The vibration degree depends on the quantity, size and composition of the impurity particles being rolled. Although the typical frequency form will not be generated, a disturbing noise can be heard.Failure reason of ina imported bearing
  • The causes of rolling bearing noise are complex. One is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this wear, the matching relationship between the bearing and the shell and between the bearing and the shaft is damaged, resulting in the axis deviation from the correct position and abnormal noise when the shaft moves at high speed. Failure reason of ina imported bearing
  • When the bearing is tired, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient bearing lubrication, dry friction and bearing breakage will produce abnormal sound. After the bearing is worn and loose, the cage is loose and damaged, which will also produce abnormal noise.Failure reason of ina imported bearing
  • In the daily use of bearings, we need to pay careful attention to their use. Let’s take a look at the nine matters we need to pay attention to.Failure reason of ina imported bearing
  • Riveted parts in the harvester, such as moving knife assembly, are generally made of cold extrusion. They should not be heated during riveting. If heated, the material strength will be reduced. After riveting, the forming punch shall be used to strengthen the firmness of the blade and cutter rod.Failure reason of ina imported bearing
  • Wearing parts, especially pin shaft, pressing plate, sleeve and sizing block, cannot be replaced by adding more butter in maintenance. For example, parts worn to the limit for a long time will shorten the service life of other machinery.Failure reason of ina imported bearing
  • For shaft repair without balancing machine, when balancing is required for repairing various shafts, a thrust bearing can be installed at one end of the shaft and clamped on the three claws of the lathe, and the other end can be supported by the center.Failure reason of ina imported bearing
  •  If the lathe is short, the SKF Bearing installed on the shaft at the other end can be clamped by the center frame to correct the balance. However, when balancing the weight, tighten it with screws and try not to balance the weight by electric welding.Failure reason of ina imported bearing
  • In the maintenance, due to the variety of bearing materials and models, it is difficult to purchase, so it can be processed with waste shafts. At present, most shafts in China are mainly made of 45# carbon steel. IF quenching and tempering are required, in case of poor conditions, oxygen and earth furnace can be used to heat the required parts to red and black and place them in salt water, depending on the demand.Failure reason of ina imported bearing
  • When processing sleeve parts, pull the oil groove in the sleeve hole as much as possible. Because it is very difficult to refuel some parts of the harvester, butter and heavy oil can be used where it is difficult to refuel, except nylon sleeve. Where nylon sleeve is used, cast iron, copper and aluminum shall not be used instead, because the nylon sleeve bears certain impact and does not deform.Failure reason of ina imported bearing
  • The key and keyway on the pulley and shaft shall be repaired in advance, and the size of the key shall not be increased, otherwise the strength of the shaft will be affected. The keyway on the shaft can be repaired and welded with electric welding filler, and a key groove can be milled in the opposite direction of the old key. The keyway on the pulley can be inlaid (transition fit). After inlaying, use countersunk screws to tap and tighten the key in the socket seam.Failure reason of ina imported bearing
  • For the maintenance of the hydraulic part of the harvester, remove the distributor and flow reducing valve, and use the air pump to flush the pressure of each pipe fitting. The hydraulic oil shall be filtered and vented during secondary loading. The maintenance of hydraulic assembly is mainly the seal, and the seal shall be replaced after removal

The first is to identify and check the rolling sound of NTN bearing

  • We can use sound detector to check the rolling sound and sound quality of Timken bearing in operation. Because Timken bearing will emit abnormal sound and irregular sound even if there is slight peeling and other damage, it can be distinguished by sound detector to prevent it in advance.Failure reason of ina imported bearing
  • Secondly, the vibration of Timken bearing in operation is identified and checked
  • Timken bearing vibration is very sensitive to the damage of Timken bearing. For example, peeling, indentation, corrosion, crack, wear, etc. will be reflected in the vibration measurement of Timken bearing. Therefore, the vibration can be measured by using a special Japanese Timken bearing vibration meter (frequency analyzer, etc.), and the specific situation of abnormality can not be inferred through frequency division.Failure reason of ina imported bearing
  •  The measured values are different due to the service conditions of Timken bearing or the installation position of sensor, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
  • After that, check according to the temperature of Timken bearing
  • The temperature of Timken bearing can generally be inferred from the temperature outside the Timken bearing chamber in Japan. It is more appropriate if the outer ring temperature of Timken bearing can be directly measured by oil hole. Usually, the temperature of Timken bearing rises slowly with the start of operation and reaches a stable state after 1-2 hours. The normal temperature of Timken bearing varies with the heat capacity, heat dissipation, speed and load of the machine.Failure reason of ina imported bearing
  •  If the lubrication and installation parts are appropriate, the Timken bearing temperature will rise sharply and abnormal high temperature will occur. At this time, the operation must be stopped and necessary preventive measures must be taken. Failure reason of ina imported bearing
  • According to a large number of test data, since the temperature is affected by lubrication, speed, load and environment, the value in the table only represents the approximate temperature range. Using the thermal sensor, the working temperature of Timken bearing can be monitored at any time, and the automatic alarm or stop when the temperature exceeds the specified value can be realized to prevent the occurrence of combustion shaft accident.Failure reason of ina imported bearing
  • In order to improve the actual fitting accuracy of NTN bearing during installation, it is necessary to accurately measure the fitting surface dimensions of the inner hole and outer circle of NTN bearing by using the measurement methods and tools that do not deform the NTN bearing. NTN bearing
  • All the measurement items related to the inner diameter and outer diameter can be measured, and the measured data can be comprehensively analyzed. Based on this, the dimensions of the installation parts of Japanese NTN bearing that accurately match the shaft and seat hole can be measured. When actually measuring the corresponding size and geometry of the matched shaft and seat hole, it shall be carried out under the same temperature conditions as when measuring NTN bearing.NTN bearing
  • In order to ensure a high actual matching effect, the roughness of the surface of the shaft and seat hole matched with the NTN bearing shall be as small as possible.NTN bearing
  • During the above measurement, two groups of marks indicating the direction of large deviation shall be made on the outer circle and inner hole of NTN bearing and the corresponding surface of shaft and seat hole on both sides close to the assembly chamfer, so as to align the large deviation of matching two sides with the same direction during actual assembly, so that the deviation of both sides can be partially offset after assembly.NTN bearing
  • The purpose of making two groups of orientation marks is to comprehensively consider the compensation of deviation, not only improve the rotation accuracy of the supports at both ends, but also partially eliminate the coaxiality error of the seat hole between the two supports and the journal at both ends. NTN bearing
  • The implementation of surface strengthening measures on the mating surface, such as sand blasting, using a precision plug with a slightly larger diameter to plug the primary inner hole, etc., are conducive to improving the mating accuracy.NTN bearing