NTN bearings are mass-produced mechanical parts with strict manufacturing accuracy and high degree of technical specialization. Therefore, for the vast majority of bearing varieties that are easy to buy, it should be more cost-effective to buy than repair. The repair of bearings can only be considered under the following circumstances, namely:
(1) The failure forms of a large number of bearings of the same model used in large factories are Method Of Ntn Bearing mainly the wear, fatigue or fretting abrasion of the rolling surface. In particular, the damaged parts are mostly cages or rolling elements, and the rings or washers still have repair value;
(2) Large and extra large bearings are on the verge of failure or have failed without major damage to parts, or valuable NTN bearings must try to prolong their effective service life;
(3) Some bearing varieties that are really difficult to buy have to be Method Of Ntn Bearing repaired without spare parts after failure, especially imported bearings;
(4) The bearing has slight damage, such as slight water rust during storage and slight fretting abrasion during transportation. Such cases Method Of Ntn Bearing are easy to repair and regrettable to discard.
In addition to the economy, the repair of NTN bearing is also technical, which requires the repairer to fully understand the corresponding technical requirements of the bearing and the characteristics of the bearing and its parts in structure, process and materials. Otherwise, it is difficult to ensure that the bearing repair has a satisfactory effect.
if users can obtain the cooperation of professional bearing enterprises, Method Of Ntn Bearing they may get the following benefits:
(1) It can clarify the technical requirements of each process of repair and how to ensure the overall quality of the repaired bearing,
(2) Many special experiences of professional bearing factories can be used, which can reliably, Method Of Ntn Bearing efficiently and economically meet the process requirements;
(3) You can order tooling cards and molds from professional bearing enterprises for repair business, which may be more economical and save a lot of trouble;
(4) You can order accessories such as cages, rolling elements and rivets from professional bearing enterprises, which may make the repair simple, convenient and economical.
If the NTN bearing is installed on the set sleeve, determine the direction of the bearing pedestal. The position of the oil nozzle on the top cover of the bearing pedestal shall always be on the other side of the set nut.
Attention must be paid to the Method Of Ntn Bearing direction of the whole bearing pedestal, because the top cover and base must be installed in the original direction.
1. The installation and disassembly of bearings are sometimes involved; The moving of heavy objects, the use of tools and other equipment or the use of high-pressure oil.
2. Ensure the environment is clean.
3. Check the dimension and shape tolerance of the journal.
4. Check that the surface roughness Ra of the support surface is not Method Of Ntn Bearing greater than 12.5 μ m。 Flatness tolerance shall be it7. For applications with lower requirements, it8 can be used.
If the bearing can be used correctly without selection error, it can be used for a long time before the Method Of Ntn Bearing service life of SKF Bearing. On the other hand, there are unexpected early damage, and the early damage that can not withstand use.
As the reasons for this early damage, there are insufficient consideration on use and lubrication, and then there are foreign matter intrusion, large bearing assembly error and shaft deflection, insufficient research on shaft and bearing housing, etc. It can be said that there are many cases in which these reasons coincide with each other.
Therefore, on the basis of fully understanding the machine, service conditions and peripheral structure of the bearing, if we can understand the situation before and after the accident, and then investigate the damage of the bearing and various reasons, we can prevent the recurrence of similar accidents.
The way to decide when to lubricate and when to stop oiling is very Method Of Ntn Bearing simple: make a baseline, make an observation schedule and monitor when oiling.
1. Develop a baseline
The bearing foundation line reflects the DB strength under the condition of normal operation, no visual error and sufficient lubrication.
There are three ways to formulate the foundation line:
1) Comparison method: if there are multiple bearings of the same type, these SKF bearings can be compared together.
Observe each bearing with the same test method or from the same angle. Analyze decibel intensity and sound quality. If there is no essential difference (less than 8 dB), we can set it as the basic DB strength of each bearing.
2) Set the basic line when adding lubricating oil: when adding lubricating oil, listen to the sound intensity. When the sound intensity decreases and then increases. At this time, do not add too much lubricating oil, and set it as the base line.
3) Historical records: observe the decibel strength of the bearing, record it every day, and then compare the record results of 30 days. If the decibel intensity changes little or no (less than 8 dB), we can set this as the base line and use it for the comparison of future observations.
2. Set observation schedule
For example, the criticality of equipment related to total output, environmental results and operation results is the main factor for selecting, setting and evaluating mechanical systems. When the basic observation line is formulated, it is very necessary to test once a month.
For those high decibel bearings to be lubricated, the frequency of detection should be more frequent, so that the possible changes can be observed. If a bearing is in a state of being destroyed, the lubricating oil can only temporarily cover up the error.
However, the decibel intensity will soon rise to indicate the existence of errors. In some cases, this phenomenon will appear in a few minutes, while in others, it will take a few days.
3. Inspection during lubrication
If the decibel of a SKF Bearing exceeds 8 decibels of the base line, we think the bearing needs lubrication. When we realize that this bearing needs lubrication, knowing when to stop oiling will prevent over lubrication. This can be done in the following three steps:
1) Calculate the consumption based on the guidance of the bearing manufacturer, and then inject lubricating oil without too much. This step is very subjective and has nothing to do with ultrasound, and this step has never failed.
2) When lubricating oil is injected, the lubricating technician shall use ultrasonic instrument to detect the bearing. Fill oil slowly until the decibel strength drops to the base line.
3) If there is no basic line as a guide, the amount of lubricating oil should stop when the sound decreases and then rises. At this time, the technician should stop using lubricating oil.
4. Ultrasonic bearing inspection
Ultrasonic inspection or monitoring is a reliable way to detect the initial (initial) stage of bearing damage. When the temperature rises or the intensity of low-frequency vibration increases, the ultrasonic warning will sound first.
This method of inspecting bearings is useful when the bearings are damaged due to excessive use, lack of lubricating oil or excessive lubricating oil at the initial stage.
5. Detect signs of failure
Ball bearings, like the metal on the track, such as rollers or ball bearings, will deform slightly when they begin to be overused. This will produce irregular surfaces, resulting in an increase in the emitted ultrasonic waves.
The change in amplitude obtained from the initial readings indicates one or two conditions: premature failure or lack of lubricating oil and initial bearing failure. If the ultrasonic wave exceeds the base line by eight decibels, it will be accompanied by continuous impact noise,
which indicates the failure of lubricating oil (dry bearing surface). If the ultrasonic reading exceeds the expected reading and reaches 12 dB, there will be a collapse noise. This noise can be assumed that the SKF Bearing has begun to enter the failure mode.