Analysis of distinguishing the burn fault of Koyo bearing
Analysis of distinguishing the burn fault of Koyo bearing
2022年5月14日
Method of identifying INA Bearing
2022年5月14日

Inspection of vibration fault of punching outer ring needle roller bearing during operation

Measurement of shaft vibration roller bearing during operation

  • Let’s briefly introduce the rolling sound of the bearing first. The size and sound quality of the rolling sound should be checked by using a sound detector to check the of the stamping outer ring needle roller bearing in operation. The problem will be accurately judged with advanced tools. Even if the bearing has slight peeling and other damage, it will also produce abnormal sound and irregular sound, which can be distinguished by the sound detector.
  • Then, check the vibration of the outer ring needle roller bearing to see if the damage of the bearing is very sensitive. Whether peeling, indentation, corrosion, crack, wear, etc. will be reflected in the bearing vibration measurement. 
  • Therefore, the vibration can be measured by using a special bearing vibration meter (frequency analyzer, etc.), and the specific abnormal situation can not be inferred by frequency division. However, the values measured by each machine are different due to the service conditions of the bearing or the installation position of the sensor, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
  • Contact measurement can be used to measure the axial vibration of punched outer ring needle roller bearing. A black gold contact surface is adopted, which is directly pressed on the journal surface with a spring. The black gold is rigidly connected with an extended metal rod and passes through the bearing bush, and the black gold surface is close to the rotor surface. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Therefore, the vibration of the black gold surface directly reflects the axial vibration, and the vibration of the extension rod rigidly connected with the black gold surface also reflects the axial vibration. Using eddy current sensor to measure the vibration of metal extension rod avoids the interference to the bearing vibration measurement when the coil outlet passes through the excitation current.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • For the treatment of the axial vibration of the rear bearing, in order to ensure the lift of the shafting on site, the elevation of the stamped outer ring needle roller bearing or the bearing of the exciter is often raised, resulting in serious side contact of the rear bearing, resulting in large vibration of the rear bearing. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • The rear bearing is preset to be inclined, so that the contact between the bearing bush and the journal is better, which not only ensures the contact of the bearing bush, but also conforms to the lift of the shaft system, and has received good results. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • At the same time, the spherical surface of the shaft must be grinded well to give full play to the self positioning function of the bearing bush. In addition, the tightening force of the bearing bush shall be adjusted properly and the foot screw shall not be loose. In this way, the problem of large axial vibration of the rear bearing can be properly handled.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Treatment of large disturbing force of rotor
  • When there is neither the error of axial vibration measurement nor the problem of large axial vibration caused by the contact of rear bearing pad edge, it is analyzed and judged that the axial vibration exceeding the standard is true, and the vibration is power frequency, the vibration can be improved through on-site high-speed dynamic balance. As long as the method is appropriate, basically one balance can be successful, up to two times.
Inspection of vibration fault of punching outer ring needle roller bearing during operation

Inspection of vibration fault of punching outer ring needle roller bearing during operation

  • Proper material selection is still a factor that must be considered in bearing failure analysis. The main task of failure analysis of double row angular contact ball bearing 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.
  • The installation condition is one of the primary factors in the use factors. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • The improper installation of the bearing often leads to the change of the stress state between the parts of the whole set of bearing, and the double row angular contact ball bearing operates in an abnormal state and fails early. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • According to the technical requirements of bearing installation, use, maintenance and repair, monitor and inspect the load, speed, working temperature, vibration, noise and lubrication conditions of the running bearing, find out the causes immediately and adjust them to make them return to normal.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  •  Double row self-aligning roller bearing is a precision component, and its use must be carried out with corresponding caution. No matter how high-performance bearings are used, if they are not used properly, the expected high performance will not be obtained. Precautions for the use of bearings are as follows.
  • As soon as the double row self-aligning roller bearing moves, the inner ring takes the raceway surface of the outer ring. Because the rolling element is in rolling contact, the running track is a dark surface, and the running track attached to the raceway surface is not very important. 
  • Therefore, the load premise can be known. Therefore, under the environment of removing the bearing, what types of bearing seals are there. Please pay close attention to and observe the running track of the raceway surface. If you carefully observe the running track, you will be able to bear radial load, large axial load, torque load, or there is no extreme rigidity inequality on the bearing housing.
  • When removing the double row self-aligning roller bearing for inspection, first make appearance records by photography and other methods. In addition, confirm the amount of remaining lubricant and sample the lubricant before cleaning the bearing.
  •  The limit speed of rolling bearing is the allowable high speed under certain load and lubrication conditions, which is related to many factors, such as bearing type, size, load size and direction, lubricant type and lubrication mode, clearance, cage structure and cooling conditions.
  • The factors affecting the limit speed are: load size, load type and direction, lubricant and lubrication mode. Experience has proved that the ultimate speed of the bearing can also be improved by improving the manufacturing accuracy of the bearing, appropriately increasing the clearance of the bearing and adopting the cage of special material and structure.
  • The reasons for high bearing temperature include: the quality of lubricating oil does not meet the requirements or deteriorates, and the viscosity of lubricating oil is too high; The mechanism assembly is too tight (insufficient clearance); The assembly of one-way bearing is too tight; The bearing race rotates on the shaft or in the shell; Excessive load; Broken bearing cage or rolling element, etc.
  • The rolling bearing is allowed to make slight running noise during operation. If the noise is too loud or there is abnormal noise or impact sound, it indicates that the bearing is faulty.
  • 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. The bearing deviates from the axis at high speed, which leads to the wear of the bearing and the bearing at the correct position. 
  • When Timken bearing is tired, its surface metal 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 loosened, the cage is loose and damaged, which will also produce abnormal noise and damage to the bearing.
  • During the disassembly and inspection of rolling bearing, the fault and damage cause of one-way bearing can be judged according to the damage of bearing.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • 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 bearing changes, the preloading method. What are the seal types of the bearing when in use?, It will even change its relative position, and the preload can be maintained at a certain level.

Gear transmission roller bearing during operation

  • Gear transmission is a kind of mechanical transmission widely used. Almost all kinds of transmission devices of machine tools have gear transmission. There are two purposes of using gear transmission device in the servo feed system of NC machine tool. 
  • One is to change the output of servo motors with high speed torque (such as stepping motors, DC and AC servo motors, etc.) into the input of actuators with low speed and high torque; The other is to make the moment of inertia of ball screw and worktable have a small proportion in the system. In addition, the required motion accuracy can be guaranteed for the open-loop system.
  • In order to minimize the influence of tooth side clearance on the machining accuracy of NC machine tools, structural measures are often taken to reduce or eliminate the empty path error of gear pairs. For example, the double piece gear staggering method, the eccentric sleeve is used to adjust the center distance of the gear pair, or the axial gasket adjustment method is used to eliminate the gear backlash.
  • Compared with the use of synchronous toothed belt, the use of gear reduction device in the feed transmission chain of NC machine tool is more likely to produce low-frequency oscillation. Therefore, the reduction mechanism is often equipped with damper to improve the dynamic performance.

Synchronous toothed belt roller bearing during operation

  • Synchronous toothed belt drive is a new type of belt drive. He uses the tooth shape of the toothed belt to mesh with the teeth of the pulley in turn to transmit motion and power, so it has the advantages of belt transmission, gear transmission and chain transmission, and has no relative sliding. The average transmission is more accurate and the transmission precision is high. 
  • Moreover, the toothed belt has high strength, small thickness and light weight, so it can be used for high-speed transmission. The toothed belt does not need special tension, so the load acting on the shaft and bearing is small and the transmission efficiency is high. It has been widely used in CNC machine tools. The main parameters and specifications of synchronous toothed belt are as follows:
  • Pitch pitch P is the distance between two adjacent teeth on the pitch line. Since the length of the strength layer remains unchanged during operation, the center line of the strength layer is specified as the pitch line (neutral layer) of the toothed belt, and the perimeter l of the pitch line is taken as the nominal length of the toothed belt.
  • The modulus is defined as M = P / π, which is the main basis for the calculation of the size of toothed belt.
  • Other parameters other parameters and dimensions of toothed belt are basically the same as those of involute rack. The calculation formula of tooth profile of toothed belt is different from that of involute rack, because the pitch of toothed belt is on the strength layer, not on the high and middle part of the tooth.
  • The marking method of toothed belt is: module * width * number of teeth, i.e. m * b * Z.

For the installation and disassembly of IKO bearing

  • Basic knowledge of installation, use and maintenance of IKO bearing an important difference between automobile and ordinary mechanical bearing is that the bearing is used in a mobile environment, so its stress condition and working condition are more complex. At the same time, as a very precise mechanical part, the correct installation, use, lubrication and maintenance are very important to realize the basic functions of automobile.
  • For the installation and disassembly of IKO bearing, clean the bearing and its matching parts with clean kerosene or gasoline;Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Check whether the bearing to be used is consistent with the prototype number and whether the matching part size is qualified;Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Press the bearing in with the special assembly tool sleeve. The diameter of the tool sleeve shall not exceed the outer diameter of the bearing retaining edge. The force shall be uniform during assembly. Do not impact and rough assembly;Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • After the bearing is installed, rotate the bearing and related parts to check whether there is jamming and abnormal noise; Inject specified grease or lubricating oil according to the requirements of main engine components;Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • When assembling large bearings and products with large surplus between bearings and shaft and seat holes, IKO bearings must be heated in oil bath, and the oil temperature is about 80 ℃; When disassembling the bearing, special tools for drawing must be used, and iron is strictly prohibited

We want to emphasizeimportant to keep IKO bearings lubricated and clean.

  • Regular inspection of the bearing is a very important work to maintain the bearing in good condition, which can also reflect the discovery of problems. Matters needing attention and relevant knowledge about bearing in use.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Therefore, before we inspect the bearing, we should first clean the surface of the bearing, and then disassemble the parts around the bearing.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  •  It should be noted that the oil seal is a very fragile part, so you need to be extra careful during inspection and disassembly. Do not apply excessive force to avoid damage to the parts. Then carefully check the oil seal of the bearing and its surrounding parts. If there are bad symptoms, be sure to replace it. The bad oil seal will lead to the damage of the bearing and the abnormal cloud shape of the bearing, resulting in the shutdown of the equipment.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Secondly, we have to check the lubricant of the bearing. Lubrication is very important, not only for IKO bearings, but also for all bearings. However, please note that the bearing should not add too much grease.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Rub with a little lubricant between your fingers. If there are pollutants, you can feel them; Or apply a thin layer of lubricant on the back of the hand, and then conduct light sealing inspection.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • For IKO bearings lubricated with engine oil, after draining the old engine oil, if possible, refill 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. Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Note: the engine oil is filtered before use. When replacing the grease of the bearing lubricated with grease, the arbor used shall avoid connecting the angle of cotton to any part of the bearing. Because these residual fibers may wedge between rolling parts and cause damage, especially in the application of small bearings.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • The accuracy grade of IKO bearing is increased from grade 0. Grade 0 is sufficient for general purposes, but grade 5 or higher accuracy is required when used in the conditions or occasions shown in Table 1.Inspection of vibration fault of punching outer ring needle roller bearing during operation
  • Although the above accuracy levels are based on ISO standards, their names are different in national standards.
  • The Accuracy grades applicable to various IKO bearing types and the comparison between national standards are listed.Inspection of vibration fault of punching outer ring needle roller bearing during operation