The cause of oil leakage of oil seal and its maint

2022-07-22
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Analyze the causes of oil leakage of oil seal and its maintenance methods

oil seal is an important part of various mechanical equipment and is widely used. Its performance and quality directly affect the reliability of various mechanical equipment. Some oil seals have a long service life of one year, a few months or even three to five days. They are scrapped due to oil leakage due to lax sealing. This situation has seriously affected the working efficiency of various mechanical equipment, not only increased fuel consumption and production costs, but also polluted the environment

I. working principle of oil seal

1 In the free state, the inner diameter of the oil seal lip is smaller than that of the journal and has a certain amount of interference

sharp drop in hardness

2 After installation, the interference pressure of the oil seal blade and the contraction force of the self tightening spring should produce a certain radial pressure on the rotating shaft

3. During operation, the oil seal lip forms a 0.25 ~ 0.5mm wide sealing contact ring under the action of radial pressure. Under the action of lubricating oil pressure, the oil seeps into the oil seal edge and the rotating shaft to form an extremely thin oil film. The oil film forms a "Crescent" surface on the outer edge of the rotating shaft and the oil seal edge under the action of oil surface tension, so as to prevent oil from overflowing and play a sealing role

II. The main factor causing oil leakage of oil seal

the loose sealing of oil seal is the main factor causing oil leakage. When the shaft is worn to form a groove, even if the new oil seal is replaced, it is because the contact pressure between the oil seal lip and the shaft decreases, resulting in too small interference between the diameter of the oil seal lip and the journal after installation

III. countermeasures for oil leakage due to loose oil seal

1 Master and identify the basic knowledge of fake and inferior products, and purchase high-quality and standard oil seals

2. Before installation, if the outer surface of the journal has low roughness or rust spots, rust, burrs and other defects, it shall be polished smooth with fine abrasive cloth or oilstone; Apply clean engine oil or lubricating grease to the corresponding position of the oil seal lip or journal. Apply sealant to the outer ring of the mold oil seal, wrap the keyway on the shaft with hard paper to avoid scratching the lip of the oil seal, and use a special tool to rotate and press the oil seal inward. Do not hit the punch hard to prevent the oil seal from deforming or breaking the spring; In case of lip flanging, spring falling off and oil seal deflection, it must be removed and reinstalled. It should be noted that when the journal is not worn and the oil seal spring force is sufficient, do not tighten the inner spring without authorization

3. The oil seal applied to machinery generally has poor working conditions, large environmental temperature difference, much dust, and frequent machine vibration, which constantly changes the stress status of the parts. Therefore, it is necessary to check, maintain and maintain frequently

4. In case of serious wear of journal and bearing, aging of oil seal rubber or failure of spring, repair and replace corresponding parts in time

5. For abnormal heating parts or assemblies, the fault shall be removed in time to avoid mechanical overspeed and overload operation, so as to prevent the oil seal lip temperature from rising, rubber aging and early wear

6. Check the oil level frequently. If there are too many impurities in the oil and there are alloy powder and metal iron filings, replace the oil completely. The brand and quality of the replaced oil should meet the seasonal assumption that the test objects are mainly large tonnage (above 10t). With the booming global population

7 The temporarily unused oil seal shall be properly kept to prevent being stained with oil, dust or exposed to the sun

8. When the journal is worn into a "V" shaped groove, which makes the contact pressure between the new oil seal lip and the shaft drop and can not seal the oil, AR-5 two-component adhesive imported pump agent can be used for repair, which is simple, reliable and wear-resistant, or the method of oil seal displacement can be used for repair

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