Methods to deal with oil seal leakage

Oil seal is an important part of various mechanical equipment. Although small, it is widely used. Its performance and quality directly affect the reliability of various mechanical equipment. Some oil seals have a long life of one year, at least a few months or even three to five days. The oil leaks and is scrapped due to poor sealing, which is a serious situation. It affects the work efficiency of various mechanical equipment, not only increases fuel consumption and production costs, but also pollutes the environment.

Main factors causing oil seal leakage

Insufficient sealing of the oil seal is the main factor causing oil leakage. When the shaft is worn to form grooves and cannot be sealed even if the new oil seal is replaced, the contact pressure between the oil seal lip and the shaft drops, causing the diameter of the oil seal lip to be in line with the shaft after installation. The interference of the neck is too small.

The 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;

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

3. When working, 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 penetrates between the oil seal blade and the shaft to form an extremely thin A layer of oil film, which is affected by the surface tension of the oil, forms a "crescent" surface on the outer edge of the rotating shaft and the oil seal blade to prevent the oil from overflowing and play a sealing role.

The countermeasures of oil leakage due to inadequate sealing of oil seal

1. The oil seals applied to machinery generally have harsh working conditions, large environmental temperature differences, a lot of dust, and frequent machine vibrations, which make the mechanical conditions of mechanical parts constantly change, so frequent inspections, frequent maintenance and frequent maintenance are required;

2. Master and identify the basic knowledge of counterfeit and inferior products, and choose high-quality and standard oil seals;

3. Before installation, if the outer surface of the shaft journal has low roughness or has defects such as rust spots, rust, burrs, etc., it should be smoothed with a fine emery cloth or oil stone; clean oil or grease should be applied to the oil seal lip or the corresponding position of the journal. Coat the outer ring of the oil seal with sealant, and wrap the keyway on the shaft with hard paper to avoid scratching the oil seal lip. Use a special tool to rotate the oil seal inward, and do not hit hard to prevent the oil seal from deforming. Or squeeze the spring to fail; if the lip flanges, the spring falls off and the oil seal is skewed, it must be removed and reinstalled. It should be noted that when the journal is not worn and the oil seal spring has sufficient elasticity, do not tighten the inner spring without authorization;

4. If the journals and bearings are severely worn, the oil seal rubber is aging, or the spring fails, repair and replace the corresponding parts in time;

5. Always check the oil level of the engine oil. If there are too many impurities in the engine oil, alloy powder, metal iron filings, the new engine oil must be completely replaced, and the brand and quality of the engine oil must meet the requirements of the season;

6. For parts or assemblies that are abnormally hot, the malfunction should be resolved in time to avoid mechanical overspeed and overload operation to prevent the temperature of the oil seal lip from rising, rubber aging, and early wear of the lip;

7. Oil seals that are not used temporarily should be kept properly to prevent them from being stained with oil, dust or sun exposure.