1. Pressure difference occurs inside and outside the reducer
During the operation of the reducer, the friction and heat generated by gear meshing and the influence of ambient temperature will cause the temperature inside the machine to rise. Since the volume of the box remains unchanged, the internal pressure increases. If the ventilation holes are too small or blocked by dust or oil, the machine cannot equalize the pressure with the outside world, and lubricating oil will seep out from the gaps that are not tightly sealed under the pressure difference.
2. Unreasonable structural design or manufacturing process
Box deformation and gaps: If the casting is not fully annealed or aged during manufacturing, the internal stress is not eliminated, and it is easy to deform and create gaps in subsequent use; in addition, if the inspection hole cover is too thin, it will easily deform after tightening the bolts, resulting in uneven joint surfaces, which will cause leakage.
Poor return flow: If there is no oil return groove designed on the box, the lubricating oil thrown by the gear to the shaft seal, end cover or joint surface cannot flow back to the oil pool, and will easily leak out under the action of pressure difference.
Shaft seal defects: Early or poorly designed shaft seal structures (such as felt seals) have poor compensation performance, and when the contact between the journal and the seal is not ideal, it is easy to fail in a short time.
3. Too much oil
If the amount of oil injected exceeds the specified upper limit, the oil pool will be violently stirred when the reducer is running, causing lubricating oil to splash everywhere in the machine. A large amount of lubricating oil accumulates at the shaft seal and joint surface, eventually leading to leakage.
4. Improper maintenance and installation processes
Seal assembly problems: If special tooling is not used during assembly, the oil seal lip is easily damaged or installed skewed; in addition, oil leakage can also be caused by installing the seal in the opposite direction and failing to replace aging seals in time.
Foreign matter intrusion: Improper processing technology of the shaft (such as unreasonable surface roughness, insufficient hardness), or foreign matter (such as metal impurities, coal powder) entering the oil seal lip will accelerate the wear of the oil seal lip and the shaft, causing leakage.
Insufficient cleaning of the joint surface: If the dirt on the joint surface is not completely removed during maintenance, or the sealant selected is inappropriate, it will also lead to loose sealing.
