Causes of oil leakage at the outer edge of the oil seal

Oil leakage from the outer edge of the oil seal is a common problem in mechanical equipment. It may cause the leakage of lubricating oil or other fluids, which may cause damage to the equipment and deteriorate its performance. The main function of the oil seal is to prevent the internal lubricating oil from leaking out and external dust and dirt from entering the bearing or mechanical device. The reasons for oil leakage from the outer edge of the oil seal can be analyzed from many aspects, usually involving improper installation, quality problems of the oil seal itself, the condition of the bearing or shaft, and the influence of the operating environment.

Common causes of oil leakage from the outer edge of the oil seal

1. Improper installation

Improper installation:  If the oil seal is not fully in place during installation, or if a special installation tool is not used during installation, the oil seal will be deformed or damaged. In particular, the outer edge of the oil seal and the housing are not tightly fitted, forming a gap, causing oil leakage.

Tilt installation:  The oil seal is not installed completely horizontally, or it is installed at an angle, which causes the oil seal lip to contact the shaft surface unevenly, making it unable to effectively seal and causing oil leakage.

Wrong installation direction:  The oil seal is installed in the wrong direction, especially for oil seals with one-way sealing lips, installing in the opposite direction will cause the seal to fail.

2. Oil seal quality issues

Material aging or deterioration:  Aging or deterioration of the oil seal material will cause it to lose elasticity and sealing. Common causes include long-term exposure to high temperature, oxidation, ozone and ultraviolet rays, or use in an environment with incompatible chemicals.

Size mismatch:  Oil seal size mismatch (too large or too small) will lead to difficult installation, poor sealing or insufficient tightness, resulting in oil leakage. In particular, mismatched outer edge sizes will cause gaps between the housing.

Manufacturing defects:  The oil seal itself may have manufacturing defects, such as rough surface, uneven lip, uneven material, etc., which will affect its sealing effect.

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3. Condition of the shaft and housing

Shaft wear or damage:  The seal between the oil seal and the shaft mainly depends on the close contact between the lip and the shaft surface. If there is wear, scratches or pits on the shaft surface, the oil seal lip will not be able to fully fit the shaft surface, resulting in oil leakage.

Shaft runout or misalignment:  If the shaft has excessive runout or axis misalignment during rotation, the oil seal lip cannot stably seal the shaft, causing oil leakage. This situation often occurs when the bearing is worn, improperly installed, or the equipment is used for too long.

Uneven shell surface:  The seal between the outer edge of the oil seal and the shell depends on the smooth surface of the shell. If there are unevenness, dents or deformations on the shell surface, the outer edge will not be sealed tightly, causing oil leakage.

4. Impact of operating environment

High temperature environment:  Long-term exposure to high temperature environment will cause thermal aging of the oil seal material, causing it to lose elasticity and sealing ability, resulting in oil leakage. High temperature may also cause the viscosity of the lubricating oil to decrease, accelerating the aging of the oil seal.

Poor lubrication or use of incompatible lubricants:  The oil seal needs to be properly lubricated during installation to avoid initial wear. If an incompatible lubricant is used, it may cause the oil seal material to swell or soften, affecting the sealing effect.

Dust or impurity intrusion:  Dust, sand or other impurities in the external environment enter the oil seal, which may cause the seal lip to wear more, resulting in oil leakage.

5. Overload or excessive wear

Equipment overload operation: If the equipment is operated under overload conditions for a long time, it may cause excessive wear or deformation of the shaft and bearing, which may lead to a decrease in the sealing effect of the oil seal and cause oil leakage.

Excessive mechanical vibration: Excessive mechanical vibration will cause slight relative movement between the oil seal and the bearing seat, thereby damaging the sealing lip of the oil seal and causing oil leakage.

Conclusion

There are many reasons for oil leakage on the outer edge of the oil seal, usually involving improper installation, inappropriate oil seal material or size, poor surface condition of the shaft or housing, and the influence of the operating environment. Through correct installation, selection of appropriate materials, regular maintenance and optimization of the working environment, oil leakage on the outer edge of the oil seal can be effectively prevented to ensure the normal operation and service life of the equipment.