Most fag bearings are damaged for many reasons, such as exceeding the original estimated load, ineffective sealing, too small bearing clearance caused by too tight fit, etc. Any of these factors has its special damage type and will leave special damage traces. Therefore, by examining the damaged bearing, the possible causes can be found in most cases.
Generally speaking, one-third of the bearing damage is caused by fatigue damage, the other one-third is caused by poor lubrication, and the other one-third is caused by pollutants entering the bearing or improper installation and treatment. However, these types of damage are also related to industry. For example, the pulp and paper industry is mostly due to bearing damage caused by poor lubrication or pollution, rather than material fatigue.
When inspecting the fag bearing removed during the regular maintenance and operation of fag bearing equipment and the replacement of peripheral parts, it is necessary to judge whether the secondary bearing parts can be reused and record the good or bad use. Also carefully investigate and record the appearance of the removed fag bearings. In order to find out and investigate the remaining amount of lubricant, the fag bearing should be well cleaned after sampling.
Secondly, check the raceway surface, rolling surface and mating surface of fag bearing and the wear state of cage for damage and abnormalities, especially observe the running track of raceway surface. Judge whether the bearing can be used again after considering the degree of bearing damage, machine performance, importance, operating conditions, inspection cycle, etc.
According to the inspection results, if the fag bearing is found to be damaged or abnormal, please find out the causes and formulate countermeasures according to the phenomenon of bearing damage. In addition, according to the inspection results, if there are the following defects, the fag bearing can no longer be used and needs to be replaced with a new bearing. The clearance of rolling bearing is divided into radial clearance and axial clearance. Its function is to ensure the normal operation and lubrication of rolling element and compensate thermal elongation.Several problems of ina imported bearing matching
For Timken bearings with adjustable clearance, due to the positive proportional relationship between axial clearance and radial clearance, the required radial clearance can be obtained as long as the axial clearance is adjusted. However, they are generally used in pairs (i.e. installed at both ends or one end of the shaft). Therefore, it is only necessary to adjust the axial clearance of one Timken bearing. The axial clearance is generally adjusted with gaskets, and some can also be adjusted with screws or thrust rings.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
For rolling bearings with non adjustable clearance, the radial clearance cannot be adjusted because it has been determined according to the standard during manufacturing. After such Timken bearings are installed on the shaft diameter or in the bearing seat hole, the actual radial clearance is called assembly radial clearance. During assembly, the size of the assembly radial clearance should be just enough to create the necessary working radial clearance during operation, so as to ensure the flexible rotation of the bearing.
When this kind of Timken bearing is working, due to the thermal elongation of the shaft when the temperature rises, the inner race is relatively displaced, which reduces the radial clearance of Timken bearing and even makes the rolling element stuck between the inner and outer race. Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The above phenomenon can be avoided if an axial clearance is left between one bearing (the other Timken bearing is fixed on the shaft and in the Timken bearing seat) and the side cover in the double support rolling Timken. The causes of NTN bearing failure are often multifactorial.
All influencing factors in the design and manufacturing process will be related to the bearing failure, which is difficult to judge by analysis. In general, it can be considered and analyzed from two aspects: use factors and internal factors. Use factors mainly refer to whether the installation, adjustment, use and maintenance, maintenance and repair meet the technical requirements.
The installation condition is one of the primary factors in the use factors. The improper installation of the bearing often leads to the change of the stress state between the parts of the whole bearing, and the bearing operates in an abnormal state and fails early. 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 borne by the running bearing, find out the cause immediately and adjust it to make it return to normal. In addition, it is also important to analyze and test the quality of grease and the surrounding medium and atmosphere.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
Internal factors mainly refer to the three factors that determine the quality of bearings, such as structural design, manufacturing process and material quality.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
First of all, the reasonable design and advanced nature of the structure will lead to longer bearing life. The manufacturing of bearings generally goes through multiple processing processes such as forging, heat treatment, turning, grinding and assembly. The rationality, advanced nature and stability of all the processing technologies will also affect the life of bearings. Several problems of ina imported bearing matching
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.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The metallurgical quality of NTN bearing material was once the main factor affecting the early failure of rolling bearing. With the progress of Metallurgical Technology (such as vacuum degassing of bearing steel), the quality of raw materials has been improved. Several problems of ina imported bearing matching
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.Several problems of ina imported bearing matching
The main task of NTN 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. Several problems of ina imported bearing matching
After the installation of IKO bearing, in order to check whether the installation is correct, operation inspection shall be carried out. Small machinery can be rotated by hand to confirm whether it rotates smoothly.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The inspection items include poor operation caused by foreign matters, scars and indentation, unstable torque caused by poor installation and poor processing of mounting base, excessive torque caused by too small clearance, installation error and sealing friction, etc. If there is no abnormality, the power operation can be started.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
Large machinery cannot rotate manually, so the power shall be cut off immediately after no-load start, and the machinery idles. Check whether there is vibration, noise, contact of rotating parts, etc. after confirming that there is no abnormality, enter the power operation.
Power operation, starting from no-load low speed, slowly increase to the rated operation under the specified conditions. During the test run, the inspection items are whether there is abnormal sound, IKO bearing temperature change, lubricant leakage or discoloration, etc. If any abnormality is found, stop the operation immediately, check the machinery, and remove the bearing for inspection if necessary.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The temperature of IKO bearing can generally be inferred from the external temperature of bearing pedestal. However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The bearing temperature rises gradually from the beginning of operation, and the temperature is usually stable after 1 ~ 2 hours. Several problems of ina imported bearing matching
If the bearing is not installed properly, the temperature will rise sharply, resulting in abnormal high temperature. The reasons are too much lubricant, too small bearing clearance, poor installation, excessive friction of sealing device, etc. In the case of high-speed rotation, the wrong choice of IKO bearing structure and lubrication mode is also the reason.
The rotating sound of IKO bearing is checked with stethoscope, and there are strong metal noise, abnormal sound, irregular sound and other indications of abnormality. The reasons are poor lubrication, poor accuracy of shaft or bearing seat, bearing damage, foreign matter intrusion, etc. It is more accurate to detect the clearance of fag imported bearing with lead pressing method than with feeler gauge, but it is more troublesome.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The aluminum wire used for testing should be soft and moderate in diameter. It should not be too large or too small. The ideal diameter is 1.5 ~ 2 times of the gap. In practical work, soft lead wire is usually used for testing.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
During the inspection, first open the fag inlet bearing cover, select the lead wire with appropriate diameter, cut it into a small section with a length of 15 ~ 40mm, put it on the journal and the interface between the upper and lower fag inlet bearings, cover the fag inlet bearing cover, tighten the fixing bolts according to the specified torque, then loosen the bolts, remove the fag inlet bearing cover, detect the thickness of the flattened lead wire with a micrometer, and calculate the average value of the top clearance of the fag inlet bearing.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
If the top clearance is too small, a pad can be added on the joint surface of the upper and lower tiles. If it is too large, the pad shall be reduced, scraped or the tile shall be poured again.
Adjustment of bearing bush tightening force: in order to prevent the possible rotation and axial movement of the bearing bush in the working process, in addition to matching the interference and stop parts, the bearing bush must also be compressed with fag imported bearing cover. The measurement method is the same as the top clearance measurement method. In addition to measuring the thickness of soft lead wire, the bearing bush tightening force can be calculated.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
Generally, the pressing force of bearing bush is 0.02 ~ 0.04 mm. If the pressing force does not meet the standard, it can be adjusted by increasing or decreasing the thickness of the gasket at the joint surface of fag inlet bearing and bearing seat, and the pad back is not allowed to be padded.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
In addition to ensuring the radial clearance, the sliding bearing should also ensure the axial clearance. When detecting the axial clearance, move the shaft to an extreme position, and then measure the displacement of the shaft from one extreme position to another with a feeler gauge or dial indicator, that is, the axial clearance. When the clearance of sliding bearing does not meet the requirements, it shall be adjusted. The radial clearance of split fag imported bearings is often adjusted by gaskets.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
Cooling water mainly plays multiple roles in fag imported bearing processing, such as cooling, lubrication, cleaning and rust prevention. Its correct use and maintenance directly affect the surface quality of processed parts and the service life of cutting tools. The cooling water used can be roughly divided into soda water, emulsion and synthetic grinding fluid. Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
Basically, more than 50 tons of groove fluid is used for large-scale recycling. The washed grinding products, grinding wheel dust, iron filings and oil stain are easy to cause the corruption and deterioration of cooling water, resulting in burns and corrosion of machined parts. The scientific use of cooling water can reduce the cost and improve the quality of cooling water.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
In order to ensure that the antirust process can be seriously implemented, the technology department formulates specific assessment rules according to the process requirements, and fag imports bearings and converts the component value to assess the manufacturer. The first-class antirust management personnel shall conduct a monthly process discipline inspection on the production plant, conduct a comprehensive inspection on the management of cooling water, antirust fluid.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
cleaning fluid and antirust oil, as well as the corrosion rate, cleanliness and oiling packaging of finished fag imported bearings, the management level of antirust personnel and the detection of monitoring items, score the assessment, and send the assessment results to the production plant. Establish a rust prevention management network from top to bottom, so that the rust prevention work has a good management foundation.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The quality of antirust materials directly affects the quality of product processing. Therefore, when selecting antirust materials, the physical and chemical properties shall be tested according to the quality requirements first, and then the pilot test shall be carried out after being qualified. Only when meeting the process requirements can they be used in large quantities. Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The antirust auxiliary materials selected for use shall be strictly tested according to the quality standards of different materials after entering the factory. Only after fag imported bearings are qualified can they be issued and used by the supply department. During use, the antirust materials and the prepared solution shall be tested regularly to ensure that the concentration and proportion of the solution meet the process requirements and meet the service performance. Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
The establishment of a complete material acceptance system and quality acceptance standards provides a reliable guarantee for doing a good job in rust prevention management. The function of ina inlet bearing coordination is to make the stationary ring and rotating ring of ina inlet bearing consolidate with the stationary part (usually ina inlet bearing seat) and rotating part (usually shaft) of the installation part respectively, so as to realize the basic task of transmitting load in the rotating state and limiting the position of the moving system relative to the stationary system.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
On the shaft and in the ina inlet bearing seat, the rolling ina inlet bearing is required to fix its position in three directions: radial, axial and tangent directions. Radial and tangential positioning is realized through tight fit of ina inlet bearing ring, and tight fit is adopted for axial positioning only in a few cases; Generally, axial limit parts, such as end caps and retaining rings, are used to limit the axial position within the clearance range.Several problems of ina imported bearing matchingSeveral problems of ina imported bearing matching
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