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Because NTN bearing even if the slight peeling and other damage, it will emit abnormal sound and irregular sound, so you can use the sounder to distinguish between the use of the sounding device, the angular noise of the angular contact ball bearings in operation and the sound quality Checking can play a preventive role in advance.
If the use of oil hole can directly measure the bearing outer ring temperature, it is more appropriate. Under normal circumstances, the temperature of the NTN bearing can be estimated based on the temperature of the outside of the bearing. If the lubrication and mounting parts are appropriate, the temperature of the bearing will suddenly rise and abnormal high temperatures will occur. At this time, the operation must be stopped and necessary precautions must be taken. In general, the temperature of the bearing gradually rises with the start of operation and reaches a stable state after 1-2 hours. The normal temperature of angular contact ball bearings varies depending on the heat capacity, heat dissipation, speed, and load of the machine. When necessary, the thermal sensor can be used to monitor the working temperature of the bearing at any time, and when the temperature exceeds the specified value, the alarm will be automatically alarmed or stopped to prevent the accident of the burning shaft.
The assembly of the NTN bearing is the basic operation in the fitter assembly and repair work, and adjustment and preloading of the clearance is an important part of the assembly work of the rolling bearing. Accurately understanding the process concept of clearance adjustment and preloading, and the correct application of this process method in the assembly work, is a guarantee of the quality of bearing assembly work.
The clearance of an NTN bearing refers to the maximum amount of movement that the other ring is made to make in a radial or axial direction under the condition that one ferrule is fixed, so the clearance is divided into two kinds: radial clearance and axial clearance. When angular contact ball bearings are assembled, clearance cannot be too large or too small. If the clearance is too large, the number of rolling elements that simultaneously bear the load will be reduced, the load of a single rolling element will increase, which will reduce the bearing rotation accuracy and reduce the service life. If the clearance is too small, the friction will increase and the heat generated will increase. Increases, exacerbates wear, and can also reduce bearing life. Therefore, the bearing must be strictly controlled and adjusted during assembly.
Pre-tightening means that when the bearing is assembled, an axial force is applied to the inner ring or the outer ring to eliminate the bearing clearance, and the initial deformation of the rolling element is brought into contact with the inner and outer rings. Pre-tightening can improve the bearing's stiffness and rotation accuracy under working conditions. Bearings with large loads and high rotational accuracy require most of them to operate under no-gap or even a small amount of interference. In this case, The bearing needs to be pre-tightened during assembly. The adjustment and pre-tightening of the clearance are usually done through proper axial relative displacement of the inner ring to the outer ring. It is not difficult to see from the above technical concept that through the adjustment of the angular contact ball bearing clearance, the bearing bearing capacity and rotation accuracy can be improved, and the service life of the bearing can be improved. However, at the same time, ntn bearing friction increases and the heat generation increases, so good lubrication and heat dissipation must be ensured when adjusting clearance or preload. If improperly adjusted or poorly lubricated, it will in turn cause increased bearing wear and reduced life. Correctly adjust and preload the bearing clearance, and pay attention to the following issues.
Judging fault damage adjustment preloading method for NTN angular contact ball bearings
From peeling, indentation, rust, crack, wear, etc. will be reflected in the bearing Vibration Measurement, NTN bearing vibration is very sensitive to the damage of the bearing, so the angular contact ball bearing adopts a special bearing vibration measurer ( Frequency analyzers, etc., can measure the magnitude of the vibration, and the specific circumstances of the abnormality cannot be inferred from the frequency division. Since the measured value differs depending on the conditions of use of the bearing or the mounting position of the sensor, it is necessary to analyze and compare the measured values ​​of each machine in advance and determine the judgment criteria.