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Shanghai Shang Shaft Bearing Quality Inspection Institute Co., Ltd.

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Address: 301 Shangxue Road, Jiading District, Shanghai

Causes and treatment methods of bearing ring running

2020-09-01 10:16

Usually the bearing is used in conjunction with the shaft, the bearing inner sleeve is installed with the shaft, and the bearing outer sleeve is installed with the bearing seat.If the inner sleeve rotates with the shaft, the inner sleeve is closely matched with the shaft, and the bearing outer sleeve is clearance fit with the bearing body;On the contrary, if the bearing body and the bearing outer sleeve rotate together, the bearing outer sleeve and the bearing body adopt close fit, while the bearing inner sleeve and the shaft adopt clearance fit.

In the process of running often run lap failure, which requires analysis and processing, otherwise it will cause accidents, resulting in greater losses.

One

The reason why the bearing runs
Bearing running circle is a common fault, and the reasons for running circle are various.

1. The first is improper cooperation
We know that the running bearing will produce heat. There is a temperature difference between the shaft and the inner sleeve, the outer sleeve and the bearing body. These temperature differences will cause changes in the tightness of the fit. If the size of the inner sleeve of the tightly matched bearing is larger than the outer diameter of the shaft, With the extension of time, wear will occur, and running laps are inevitable!
The temperature of the bearing body will also rise. Once the bearing body expands and the bearing clearance disappears, the bearing inner and outer sleeve will become one body. As the shaft rotates, the bearing outer sleeve will rotate in the bearing body and generate a lot of heat. The accident happened, and the inner hole of the bearing body was also worn out.
This is the difference in temperature formation due to improper tightness caused by running laps.

2. Laps caused by vibration
If the equipment vibrates greatly, the greater the load on the bearing and the bearing, and the shaft is like being beaten during operation. Over time, the shaft will be beaten and extended, and the journal will become thinner, which will destroy the original fit tightness. Under the conditions of fretting, heating, and running circles, the journal will be ground and the inner hole of the bearing body will be large.

3. Lubrication failure
When the lubrication fails, the friction generates a lot of heat, the temperature difference between the inner and outer shell of the bearing and the bearing body is large, the original matching size is destroyed, and the bearing journal and the bearing body are worn.

4. improper selection of lubricating oil and even more impurities
When the grease hardness is very high or there are impurities, it will cause weir effect to the bearing rolling element, prevent the rolling element from rotating and generate frictional heat. At the same time, it will also drive the selection of the outer sleeve in the bearing body and cause wear. When the resistance is large, this resistance can overcome the friction between the inner sleeve of the bearing and the shaft, causing the shaft and the inner sleeve to slip, causing sliding and causing wear.

5. Improper installation
Improper installation mainly refers to the fact that the heating temperature of the bearing is too high and the size cannot be recovered after the bearing expands. The remaining clearance of the free end bearing of the shaft is insufficient, resulting in friction and heat generation on the side of the bearing. The bearing, shaft and bearing body are not cleaned cleanly, resulting in jamming. Splitting the bearing seat and flattening the bearing, causing local jamming of the bearing, etc. These conditions will cause the bearing to heat up and cause the bearing to run out.
6. Long-term vibration knock, will make the shaft fatigue peeling
Once the debris is discharged, it will inevitably cause loosening and cause the bearing to run.
7. Bearing failure
Long-term bearing operation of the bearing, the raceway will produce fatigue pitting, shedding debris will produce weir effect, once the heat, at the same time produce temperature difference, will cause running laps.

II

Handling of Bearing Rings
In summary, there are many reasons for the bearing running circle, so when a failure or accident occurs, the cause must be analyzed to find out the root cause of the accident, and then take appropriate measures to deal with it according to the specific situation. Specific introduction is as follows:

 

1. Proofing and punching method

 




When the bearing runs, it is certain that the shaft hole is large, which can be avoided on the surface of the bearing body or in the hole in the bearing body. Make some sample eye contact evenly to make up for the size change with the convex part. This can temporarily resolve operational issues.

 

2. Brush plating method



Through electroplating, the metal chromium is directly plated on the shaft or bearing body to restore the basic size.

 

3. Adhesive method



When the shaft is worn or the inner hole of the bearing body is worn, it will cause the bearing to run Circle,At this time, the appropriate metal adhesive can be selected to fill the contact area gap, which can be solved after solidification.. As a reminder, the adhesive can only be used on closely fitting contact surfaces. For example, the inner bearing sleeve rotates with the shaft and the outer bearing sleeve rotates with the wheel.
4. Welding and turning method



The worn part is filled by welding long meat, and then machined to the appropriate size to restore the function of the part. However, this method will change the mechanical properties of the material due to welding, resulting in stress concentration,Therefore, it should not be used in stress-sensitive parts.
5. Set method



Set method is also commonly used,That is, first process the damage avoidance and joint part of the material, then process a sleeve and insert it on the shaft or bearing body, and then process the mating surface to the appropriate size..This method needs to pay attention to the strength of the sleeve and the damage to the shaft and the bearing body.Wait.

Three

Concluding remarks

The above is the common method of bearing recovery, special account,The key is to analyze the reasons for the wear of shafts, bearings and bearing bodies. These reasons must be eliminated and the results of treatment will be used for a long time.For example, reduce vibration, improve lubrication, improve bearing quality, etc.