There are several reasons cause oil leakage of the reducers.
1. Pressure difference between the inside and outside of the reducer: During the operation, the friction and heat of the movement and the influence of the ambient temperature increase the temperature of the reducer. If there is no vent or clogged vent, the internal pressure will gradually increase, The higher the internal temperature, the greater the pressure difference with outside, and the lubricating oil will leak from the gap under the pressure difference.
2. Unreasonable structure design of the reducer
1) The inspection hole cover is too thin, and it is easy to deform after tightening the bolts, making the joint surface uneven and leaking oil from the contact gap;
2) During the manufacturing of the reducer, the castings are not proceeded with annealing or aging, and internal stress is not eliminated, and deformation will inevitably occur, and this will result in leakage;
3) There is no oil return groove on the box, and the lubricating oil accumulates in the shaft seal, end cover or joint surface etc., then leaks from the gap under the pressure difference;
4) The shaft seal structure design is unreasonable. Early reducers mostly adopted oil groove and felt ring type shaft seal structure, which caused the felt to be compressed and deformed during assembly, and the joint surface gap was sealed. If the contact between the journal and the seal is not good, the seal will fail in a short time due to the extremely poor compensation performance of the felt. Although there are oil return holes on the oil ditch, it is very easy to be blocked and the oil return can’t work.
3. Too much lubricating oil: During the operation of the reducer, the oil pool is greatly agitated, and the lubricating oil splashes everywhere on the machine. The overfilled lubricating oil will accumulate on the shaft seal, joint surface, etc., and this will cause leakage.
4. Improper maintenance process: During equipment maintenance, due to incomplete removal of dirt on the bonding surface, improper selection of sealant, reverse installation of the seal, and failure to replace the seal in time, oil leakage may also occur.