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Elimination Of Common Bearing Problems

If the bearing is not running normally, it usually shows many symptoms, which can be roughly divided into seven categories:

 

A: The bearing is overheated;

 

B: Loud noise;

 

C: vibration;

 

D: The mechanical performance is not satisfactory;

 

E: The bearing is loose on the shaft;

 

F: High replacement frequency;

 

G: The shaft is difficult to rotate.

 

With different degrees of bearing damage, it is often the result of secondary damage. To effectively eliminate these bearing problems, you must first observe the application of these bearings, and then analyze the causes of these damages.

 

一. Bearing overheating:

 

The reason:

 

1. Lubricating grease or oil is invalid or incorrectly selected. The corresponding method is: select the correct grease or oil, and check the compatibility of the grease or oil.

 

2. The oil level is too low, the lubricant is lost from the oil seal, and the grease in the bearing box is insufficient. Countermeasure: The oil level should be slightly lower than the center of the lowest rolling element, and the grease in the bearing box should fill about 1/3 to 1/2 of the space.

 

3. The oil level is too high or the bearing box grease is completely filled, which will cause the lubricant to be stirred sufficiently and cause high temperature or oil leakage. Countermeasure: Add grease to the box to 1/2; if the oil is lubricated, the oil level is slightly lower than the center of the lowest rolling element.

 

4. Inappropriate bearing clearance, when heat flows through the shaft center, the inner ring will expand excessively. Countermeasure: Check whether the gap of the overheated bearing is within the original design range. If it is, please use a larger gap and change it to C3 or C3 to C4.

 

5. The contact type (friction) oil seal is too dry or the spring is too tight. Countermeasure: Replace the contact type oil seal and lubricate its oil seal surface.

 

6. The inner hole of the bearing box is not round, the bearing box is twisted and deformed, the supporting surface is not flat, and the inner diameter of the box hole is too small. Countermeasures: Check the bearing box and inner hole, and adjust the base plate to evenly distribute.

 

7. The rotating oil seal rubs against the gland, or the shaft shoulder rubs against the bearing seal cover. Countermeasures: Check the operating clearance of the rotating oil seal to avoid friction and prevent misalignment.

 

8. Cross positioning or there are two positioning bearings on the shaft, the internal clearance of the bearing is insufficient due to excessive axial expansion.

 

Countermeasures:

 

1) Insert an adjusting piece between the bearing housing and the flange of the end cover to release the axial preload of the bearing.

 

2) Move the end cover of any bearing box to the outside, use the adjusting piece to obtain the gap between the bearing box and the outer ring, if possible, apply axial spring force on the outer ring to reduce the axial float of the shaft .

 

9. The adapter sleeve is too tightly locked: loosen the fixed nut and sleeve and re-lock to ensure that the bearing can rotate freely.

 

10. When the shafts with two or more bearings are coupled, incorrect linear deviation or angular skew occurs. Countermeasures: Adjust the correct alignment by the adjustment piece to ensure that the shaft is coupled in a straight line, especially when there are three or more bearings running on the shaft at the same time, pay more attention.

 

11. The shaft diameter is too large, resulting in excessive expansion of the inner ring and reducing the bearing clearance.

 

Countermeasures:

 

1) Grind the shaft diameter to obtain a proper fit between the shaft and the inner ring of the bearing.

 

2) Switch to bearings with large radial clearance.

 

12. Because the material of the bearing box hole is too soft, the hole diameter becomes larger after being stressed, which causes the outer ring to slip in the box hole. Countermeasure: Improve the box material or process a steel bushing to squeeze into the box hole, and then process the inner hole of the bushing to the correct size.TIMKEN Bearing 6580/6535 online, click here to contact us and buy it.
 


 

二. Noise

 

1. Lubricating grease or engine oil is invalid, and the lubricant model is not selected properly. Countermeasures: Choosing appropriate lubricants should confirm their compatibility.

 

2. The oil level is too low or the bearing box grease is insufficient. Countermeasures: The oil level should be slightly lower than the center of the lowest rolling element, and the bearing box should be filled with grease 1/3 to 1/2 of the space.

 

3. Inappropriate internal clearance of the bearing, over-locking of the tightening sleeve, too large shaft diameter and too large interference in the bearing inner hole, etc. can all cause the bearing clearance to decrease. When heat flow through the shaft surface, the inner ring will expand excessively. .

 

Countermeasures:

 

1) Check whether the overheated bearing clearance is consistent with the original design, if it is still, you can use a larger clearance. For example, change from "0" group to "C3" from "C3" to "C4"

.

2) Improve the locking amount of the tightening sleeve, detect the radial clearance, and determine the proper position.

 

3) Adjust the matching relationship between the shaft and the inner hole of the bearing.

 

4. Dirt, sand dust or other pollutants enter the bearing box. Countermeasure: Clean the bearing box, replace the new oil seal or improve the oil seal design.

 

5. Water, acid, paint or other corrosive substances enter the bearing box. Countermeasures: Install a certain protective anti-pressure cover or throw-off ring to prevent foreign objects from entering the bearing.

 

6. The inner hole of the bearing box is not round, twisted and deformed, and the inner hole is too small. Countermeasures: Check whether the bearing box squeezes the bearing and whether the hole size is correct.

 

7. The debris and foreign matter in the bearing box before installing the bearing have not been cleaned up. Countermeasure: Carefully clean the bearing housing and the bearing itself.

 

8. (Cross positioning) There are two positioning bearings on the same shaft, causing misalignment or insufficient internal clearance of the bearing due to shaft thermal expansion. Countermeasures: Adjust the adjustment shim between the bearing box and the end cover, so that there is a certain gap between the bearing box and the outer ring.

 

9. The shaft shoulder rubs against the bearing seal cover, and the shaft shoulder diameter is incorrect and rubs with the cage. Countermeasure: Re-machine the shaft shoulder, check the diameter and fillet of the shoulder.

 

10. The outer ring and the bearing housing are twisted, and the shaft and inner ring are twisted. The reason is that the rounded corners of the box hole are too large; there is not enough support. The shoulder fillet is too large, there is insufficient support, and the two ends are not reliable. Countermeasures: Rework the fillet of the box hole and the shoulder.

 

11. Incorrect installation method, directly hitting the bearing with a hammer, resulting in knocks on the working surface of the bearing. Countermeasure: Choose the correct installation method: sleeve method, heating method, oil pressure method, etc.

 

12. The sun sheet (locking washer) of the fixed washer rubs against the bearing. Countermeasure: knock down the sun sheet or replace it with a new one.

 

13. The rotating parts in the equipment interfere with the stationary parts. Countermeasures: Check carefully to avoid interference.

 

14. Excessive bearing clearance causes vibration.

 

15. Equipment vibration, check the balance of the rotating parts of the equipment and correct it.

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三. Vibration

 

1. Dirt, foreign matter, sand or other pollutants enter the box. Countermeasure: Clean the bearing box and replace the new oil seal.

 

2. Water, acid, paint or other corrosive substances enter the bearing box. Countermeasure: Install a protective dust cover and improve the oil seal.

 

3. The inner hole of the bearing box is not round, twisted and deformed, and the supporting surface is uneven. Countermeasures: Check the bearing box, adjust the supporting surface, and adjust the gasket.

 

4. The shaft diameter is small or the adapter sleeve is not locked. Countermeasure: Check the shaft diameter, select the appropriate amount of fit, and re-tighten the adapter sleeve.

 

5. Unbalanced load, large box hole clearance, and outer ring slips in the box hole. Countermeasure: Replace the bearing box with the bore diameter that meets the design requirements.

 

6. Two or more bearings are coupled to produce axis linear deviation and angular deviation. Countermeasure: Re-adjust the shim so that the axis is coupled on the same straight line.

 

7. Incorrect installation, directly hit the bearing with a hammer.

 

8. The bearing clearance is too large.

 

9. Equipment vibration.

 

四. The mechanical cannot meet the design requirements

 

1. The internal clearance of the bearing is not appropriate, and the bearing pre-tightening force is not enough: choose a suitable bearing.

 

2. The debris and dirt in the bearing box have not been cleaned up, or the dirt, water and acidic pollutants have entered the box during operation.

 

3. The adapter sleeve is too tightly locked or not locked.

 

4. The accuracy of the bore diameter of the bearing box is not high, and the box hole is deformed and twisted.

 

5. The shaft diameter is too small, and the shaft shoulder size does not match, which interferes with the bearing.

 

6. The internal clearance of the bearing is too small due to excessive shaft diameter or box hole.

 

7. Multiple bearings are coupled, resulting in misalignment.

 

五. Difficulty in axis rotation

 

1. The choice of lubrication failure, oil level and bearing clearance.

 

2. Cleanliness and debris.

 

3. Friction: oil seal, shaft shoulder and seal, anti-loosening sheet (solar sheet).

 

4. The concentricity of the shaft is not right, and the axial jam caused by cross positioning.

 

5. The bearing box has low accuracy and distortion.

 

六. The bearing is loose on the shaft

 

1. The shaft diameter is small and the bearing bore is large.

 

2. Insufficient interference.

 

3. The adapter sleeve is insufficiently locked.
 

If you want a long bearing life, users must pay attention to bearing problems. Once a bearing has a problem, find and solve it in time to maximize the role of the bearing. Eric Bearing Limited is committed to selling excellent quality. Bearings with competitive prices and products are well received by customers and have established long-term cooperative relations with them.