1. Pressure Difference Inside and Outside the Gearbox: During the operation of the gearbox, frictional heat from moving parts and the influence of ambient temperature cause the gearbox temperature to rise. If there are no ventilation holes or they are blocked, the internal pressure of the machine gradually increases. The higher the internal temperature, the greater the pressure difference with the outside, leading to the lubricant leaking out through gaps under the pressure difference.
2. The reducer structural design is not reasonable.
The inspection cover plate is too thin, and it tends to deform after being tightened, causing the mating surface to be uneven and oil to leak through the contact gaps.
During the manufacturing process of the deceleration mechanism, casting parts were not annealed or aged, and internal stresses were not relieved, which inevitably leads to deformation, gaps, and subsequent leakage.
3) Without a return oil groove on the housing, lubricating oil accumulates in areas such as the shaft seal, end cover, and mating surfaces. Under the action of pressure difference, it leaks out through the gaps.
4) Inadequate shaft seal design. Early reducers often used oil groove and felt ring shaft seal structures, which, during assembly, compress the felt, causing deformation, and seal the gap between the mating surfaces. If the shaft collar does not contact the seal optimally, due to the felt's poor compensating properties, the seal fails within a short time. Although there are return oil holes on the oil groove, they are prone to clogging, making it difficult to utilize the return oil function.
Excessive Oil Addition: During the operation of the reducer, the oil sump is vigorously agitated, causing the lubricant to spray around the machine. If too much oil is added, a large amount of lubricant can accumulate in areas such as the shaft seal and mating surfaces, leading to leakage.