Importance of test run inspection to installation quality of ina thrust ball bearing
2022年4月12日
The common problems and Countermeasures of loading failure of imported rotary table bearing are analyzed
The common problems and Countermeasures of loading failure of imported rotary table bearing are analyzed
2022年4月13日

Precautions for correctly judging the operation law of NSK linear bearing

  • NSK bearing shows strong regularity and good repeatability in its use. When the normal high-quality bearing (linear bearing) is put into use, the vibration and noise are relatively small, but the spectrum is scattered and the amplitude is small, which may be caused by some defects in the manufacturing process, such as surface burrs.Precautions for correctly judging the operation law of NSK linear bearing

Precautions for correctly judging the operation law of NSK linear bearing

  • After moving for a period of time, the vibration and noise maintain a certain level, and the spectrum is very single, with only one or two times the frequency. The frequency spectrum above three times of power frequency rarely appears, and the bearing state is very stable and enters the stable working period.Precautions for correctly judging the operation law of NSK linear bearing
  • After continued operation and entering the later stage of use, the vibration and noise of NSK bearing began to increase, and sometimes abnormal sound appeared, but the change of vibration increase was slow. At this time, the bearing kurtosis began to suddenly reach a certain value. We believe that NSK bearing shows initial failure at this time.Precautions for correctly judging the operation law of NSK linear bearing
  • At this time, it is required to closely monitor the NSK bearing and pay close attention to its changes. Since then, the bearing kurtosis value began to decline rapidly and close to the normal value, while the vibration and noise began to increase significantly, and the increase amplitude began to accelerate. 
  • When the vibration exceeded the vibration standard (such as ISO2372 standard), the bearing kurtosis value also began to increase rapidly. Precautions for correctly judging the operation law of NSK linear bearing
  • When both the vibration standard and the kurtosis value also exceeded the normal value (the relative standard of kurtosis can be used), the bearing has entered the late fault production, so it is necessary to repair the equipment and replace the linear bearing in time.Precautions for correctly judging the operation law of NSK linear bearing
  • How to protect it and prolong its service life, the following matters should be paid attention to when using the bearing:
  • 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.
  • 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.
  • NSK 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 spalling, raceway, bead wear, etc.) is mostly less than one week. The larger the equipment capacity, the faster the speed, and the shorter the interval. 
  • Therefore, in the actual NSK bearing fault diagnosis, once the late fault characteristics are found, the bearing fault should be determined and the maintenance should be arranged as soon as possible.Precautions for correctly judging the operation law of NSK linear bearing
  • Generally speaking, the bearing quality of NSK Bearings is very strong, which is not comparable to ordinary bearing products, but even bearings can be good or bad. For example, the quality of bearings produced in authentic Japan is much better than that produced by domestic joint venture. So how to test the quality of NSK Bearings!
  • Although the new technology uses the integrated cage, it only saves materials, and the performance of rotation is worse than that of the two bodies. In general, the service life of the bearing is related to three factors: one is the quality of the bearing itself. The second is the use environment. The third is the installation method.
  • The chamfer of the bearing does not determine the quality of the bearing, but reflects the processing method of the bearing. The chamfering is black, which means that after quenching and other heat treatment, the hardness of the bearing is increased.Precautions for correctly judging the operation law of NSK linear bearing
  •  However, some people think that the chamfering is black and not good-looking, which is not completely processed. This is a misunderstanding.Precautions for correctly judging the operation law of NSK linear bearing
  • Many customers say that as long as the bearing surface is bright, it is of good quality, which is wrong. The brightness of the bearing surface should be a kind of dark brightness. The reason for this dark brightness is whether the steel used by the bearing meets the standard, its grinding process and the cutting fluid used, mainly the first two items.Precautions for correctly judging the operation law of NSK linear bearing
Precautions for correctly judging the operation law of NSK linear bearing
  •  Even if a small amount of dust invisible to the naked eye enters the bearing, it will add wear, vibration and noise to the bearing.Precautions for correctly judging the operation law of NSK linear bearing
  • When taking the linear bearing directly by hand, fully wash the sweat from your hands and apply high-quality mineral oil before stopping the operation. Pay special attention to rust prevention in rainy season and summer.Precautions for correctly judging the operation law of NSK linear bearing
  • Under the premise of some special operation, NSK bearing can achieve a life better than traditional competition and debate, especially under the condition of light load. The premise of these special operations is that when the rolling surface (track and rolling parts) is effectively separated by a lubricating oil film and limits the possible surface damage caused by pollutants. In fact, under the premise of fantasy, the so-called eternal bearing life is possible.
  • In addition to excellent quality, NSK bearing is also a very precise part. It is both a high-performance bearing. If it is not properly used in the application process, it will not only fail to achieve the expected functional effect, but also easily damage the bearing. Everyone must have paid attention to lubrication.
  • Generally speaking, the bearing quality of high-temperature bearings is very strong, which is not comparable to ordinary bearing products, but even bearings can be good or bad. For example, the quality of bearings produced in authentic Japan is much better than that produced by domestic joint ventures. So how to detect the quality of NSK Bearings!Precautions for correctly judging the operation law of NSK linear bearing
  • One cage is better than two bodies
  • Although the new technology uses the integrated cage, it only saves materials, and the performance of rotation is worse than that of the two bodies. In general, the service life of the bearing is related to three factors: one is the quality of the bearing itself. The second is the use environment. The third is the installation method.Precautions for correctly judging the operation law of NSK linear bearing
  • Whether the chamfer is bright
  • The chamfer of the bearing does not determine the quality of the bearing, but reflects the processing method of the bearing. The chamfering is black, which means that after quenching and other heat treatment, the hardness of the bearing is increased. However, some people think that the chamfering is black and not good-looking, which is not completely processed. This is a misunderstanding.Precautions for correctly judging the operation law of NSK linear bearing
  • Feel the bearing quality through the surface
  • Many customers say that as long as the bearing surface is bright, it is of good quality, which is wrong. The brightness of the bearing surface should be a kind of dark brightness. The reason for this dark brightness is whether the steel used for high-temperature bearing meets the standard and its grinding process and cutting fluid, mainly the first two items.Precautions for correctly judging the operation law of NSK linear bearing
  • Some professionals are required to inspect the bearings regularly, so as to find potential problems early, prevent unexpected machine suspension, enable production and improve the productivity and efficiency of the factory. During the use of articulated bearings, the basic external conditions of the operation of imported ina bearings should be monitored frequently, such as the measurement of temperature, vibration and noise, so as to prevent accidents.
  • These operations may accelerate fatigue and reduce the service life of bearings and damage the service life of other machine parts. In addition, increased vibration and friction may greatly increase energy consumption and the risk of premature failure. However, after the joint bearing is installed, if it is not carefully aligned, the alignment may cause the bearing to suffer additional load, friction and vibration. As a result, the bearing is damaged prematurely, so it should be aligned and straightened!
  • If the bearing considers lubrication, the lubricity of oil lubrication is dominant. However, grease lubrication can simplify the advantages of the surrounding structure of imported ina bearings. 
  • In the process of operation, the bearing requires correct re lubrication, which can make the bearing operate healthily. In order to make the bearing function well, first of all, choose the lubrication method suitable for the use conditions and purpose. Whether it is oil lubrication or grease lubrication depends on the specific situation of the bearing!
  • Even if a small amount of dust invisible to the naked eye enters the bearing, it will add wear, vibration and noise to the bearing.Precautions for correctly judging the operation law of NSK linear bearing
  • When taking NSK Bearings directly by hand, wash off the sweat on your hands and apply high-quality mineral oil before stopping the operation. Pay special attention to rust prevention in rainy seasons and summer.
  • So how to deal with the bearing damage. 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 the quality service limit known as 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. As for the damage state of the bearing, such as the clamping damage of the ring and retaining edge of the roller bearing, these reasons can be considered. 
  • These reasons also coincide with insufficient lubricant, unfitness, defects of the oil supply and drainage structure, invasion of foreign matters, bearing installation error and excessive deflection of the shaft.Precautions for correctly judging the operation law of NSK linear bearing
  •  Therefore, only investigating the bearing damage, it is difficult to know the real cause of the damage. However, if we know the use machinery and conditions of NSK bearing, the structure around the high-temperature bearing, understand the situation before and after the accident, and investigate the damage state of the bearing and several causes, we can prevent the recurrence of similar accidents.Precautions for correctly judging the operation law of NSK linear bearing
  • Through the introduction, it can be found that the correct use will not cause damage to the bearing, incorrect installation, external immersion in foreign matters and improper lubrication are the main reasons for the damage of high-temperature bearing. Precautions for correctly judging the operation law of NSK linear bearing
  • Therefore, enterprises should pay more attention to these aspects in the use of bearing to prevent the damage of bearing and affect the work.Precautions for correctly judging the operation law of NSK linear bearing
  • Generally, the rolling bearing installed with tight fit and interference must be close to the shaft shoulder. 

Test method: 

  • lighting method. Aim the electric light at the bearing and shaft shoulder and judge the light leakage. If there is no light leakage, the installation is correct; If the light leaks evenly around the shaft shoulder, it means that the bearing is not close to the shaft shoulder, and pressure should be applied to the bearing to make it close; If there is partial light leakage, it indicates that the bearing is installed obliquely. Precautions for correctly judging the operation law of NSK linear bearing
  • Tap the inner ring of the bearing with a hammer, copper rod or sleeve and install it slowly. Thickness gauge inspection method. The thickness of the thickness gauge shall be 0. 03mm start. During the inspection, try to insert several places on the end face of the bearing inner ring and the whole circumference of the shaft shoulder. Precautions for correctly judging the operation law of NSK linear bearing
  • If there is a gap and it is very uniform, it indicates that the bearing is not installed in place. Pressurize the bearing inner ring to make it close to the shaft shoulder; If the increased pressure is not tight, it means that the fillet of the journal fillet is too large and the bearing is stuck. The journal fillet should be trimmed to make it smaller; If it is found that the thickness gauge of the end face of the bearing inner ring and some parts of the bearing shoulder can pass, it means that it must be removed, trimmed and reinstalled at this time.Precautions for correctly judging the operation law of NSK linear bearing
  • If the bearing is installed in the bearing seat hole with an interference fit and the bearing outer ring is fixed by the housing hole shoulder, whether the end face of the outer ring is close to the end face of the housing hole shoulder and whether the installation is correct can also be checked with a thickness gauge.
  • Inspection of thrust bearing after installation
  • When installing the thrust bearing, check the verticality of the shaft ring and the shaft centerline. The method is to fix the dial indicator on the end face of the box shell, make the contact of the dial indicator push on the raceway of the bearing shaft ring, rotate the bearing and observe the pointer of the dial indicator. If the pointer deviates, it indicates that the shaft ring is not perpendicular to the shaft centerline. When the box shell hole is deep, it can also be inspected with an extended dial indicator.
  • When the thrust bearing is installed correctly, its seat ring can automatically adapt to the rolling of the rolling element and ensure that the rolling element is located in the raceway of the upper and lower rings. Precautions for correctly judging the operation law of NSK linear bearing
  • If it is installed reversely, not only the bearing will not work normally, but also the mating surfaces will be seriously worn. Since the difference between the shaft ring and the seat ring is not obvious, extra care should be taken during assembly to avoid mistakes. In addition, 0 should be left between the thrust bearing race and the bearing seat hole. 2—0。Precautions for correctly judging the operation law of NSK linear bearing
  •  Clearance is used to compensate the error caused by inaccurate processing and installation of parts. When the center of bearing ring is offset during operation, this clearance can ensure its automatic adjustment, avoid contact friction and make it operate normally. Otherwise, the bearing will be severely damaged.Precautions for correctly judging the operation law of NSK linear bearing