What are the common causes of oil leakage in gear reducers?

Analysis of the causes of oil leakage in gear reducers

1.1 Pressure difference between the inside and outside of the reducer During operation, the friction of the moving parts generates heat, and the ambient temperature affects the reducer's temperature. If there is no vent or the vent is blocked, the internal pressure gradually increases. The higher the internal temperature, the greater the pressure difference with the outside. Under the action of the pressure difference, the lubricating oil leaks out from the gaps.

1.2 Unreasonable structural design of the reducer

(1) The inspection hole cover plate is too thin, and it is easy to deform after tightening the bolts, making the mating surface uneven and causing oil leakage from the contact gaps.

(2) During the manufacturing process of the reducer, the castings were not annealed or aged, and the internal stress was not eliminated, which inevitably led to deformation and gaps, resulting in leakage.

(3) There is no oil return groove on the housing, and the lubricating oil accumulates in the shaft seal, end cover, mating surface, etc., and leaks out from the gaps under the action of the pressure difference.

(4) Unreasonable shaft seal structure design. Early speed reducers often used an oil groove and felt ring shaft seal structure. During assembly, the felt was compressed and deformed to seal the gaps at the mating surfaces. If the contact between the journal and the seal was not ideal, the seal would fail quickly due to the poor compensation performance of the felt. Although there were oil return holes in the oil groove, they were easily clogged, hindering the return of oil.

1.3 Excessive Oil Addition During operation, the oil sump is violently agitated, and lubricating oil splashes throughout the machine. Excessive oil addition causes a large amount of lubricating oil to accumulate at the shaft seal and mating surfaces, leading to leakage.

1.4 Improper Maintenance Procedures During equipment maintenance, incomplete cleaning of the mating surfaces, improper selection of sealant, reversed installation of seals, or failure to replace seals in a timely manner can also cause oil leaks.

1.5 For low-quality speed reducers, purchase from reputable companies with good quality and strong technical capabilities.