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Diesel generator sets valve oil seal leakage of several major causes

June 23, 2022
The sealing principle of diesel generator oil seal is that the sealing lip of the oil seal is in direct contact with the surface of the rotating shaft, forming a narrow ring belt with a width of 0.1~0.2mm, which is the sealing interface. Under the action of pre-pressure (usually spring), the average pressure of radial contact between oil seal and shaft is about 1N/mm2, when the lubricant pressure is lower than the pressure value, the oil seal can prevent leakage. But sometimes users will find that the diesel generator set still has the leakage phenomenon, what is going on? In fact, this is mainly caused by the following reasons, the user can check one by one according to the following reasons.
A, assembly reasons
1, due to press fitting tooling reasons, resulting in deformation of the oil seal after press fitting.
2、During the assembly process, the oil seal passes through the thread or spline, resulting in scratching at the lip.
3、Due to the low roughness of oil seal bit, the press-fitting force is too large, leading to the failure of spring or lip flip.
Second, the reason of skeleton
Due to oil seal spring material and manufacturing problems, resulting in its performance failure. Spring failure is in the form of over-tight or over-loose spring. When it is over-loose, the spring compression force is small and cannot achieve the sealing effect; when it is over-tight, the spring compression force is large and the fit between the oil seal and the rotating shaft is improper, resulting in abnormal wear of the oil seal and eventually oil leakage.
Third, the working medium reason
The working medium is oil. The choice of oil seal material should consider its compatibility with oil, and poor compatibility between the two will produce lip swelling, hardening, softening, cracking, etc., and eventually oil leakage will occur.
Four, lip wear causes
1、Cleanliness problem: Casting sand, machining iron chips, oil impurities, etc., accumulate in large quantities in the lip of the oil seal, and abnormal wear occurs when working.
2、The oil seal position is different from the rotating shaft, and the oil seal is pressed and installed with partial wear, and the lip is abnormally worn.
3, poor lubrication of lithium grease at the lip of the oil seal, dry friction will occur, resulting in abnormal wear.
V. Causes of shaft
1、Rotary shaft surface roughness and hardness are unreasonable.
2、Defects on the surface of the rotary shaft, such as corrosion, scratches, directional knife marks, etc.