How to deal with reducer oil leakage?

In industrial production, reducers can not only reduce input speed and increase output torque, but also provide precise speed control and other important functions. They are almost everywhere in the industrial field. However, in long-term and frequent use, reducers may have oil leakage problems. If the oil leakage is not handled in time, it will cause equipment failure, performance degradation or even damage.

In general, common types of reducers such as gear reducers, worm gear reducers, planetary gear reducers, etc. have different probabilities of oil leakage, but the common causes and treatment methods of reducer oil leakage are roughly similar.

(1) Common oil leakage phenomena and main causes of reducer oil leakage

There are three common oil leakage phenomena in reducers: oil seal leakage, sealing cover pop-up and breather leakage. Generally speaking, the corresponding causes of these three oil leakage phenomena are also different.

The main reasons for oil leakage from the shaft oil seal include: improper oil seal assembly process, improper shaft processing technology, insufficient shaft hardness, improper shaft tolerance selection, and foreign matter entering the oil seal lip.

The main reasons for the sealing cover to pop out and leak oil include: excessive pressure inside the reducer, improper selection of the sealing cover hole tolerance.

The main reasons for the breather to leak oil include: unreasonable breather structure, improper breather position selection, and excessive refueling exceeding the specified upper limit.

(2) How to deal with the three types of oil leakage?

In general, the main measures to eliminate oil leakage of reducers are to improve assembly technology, processing technology and local structure optimization.

a) Optimize the oil seal assembly process

The main reasons for oil leakage caused by improper oil seal assembly process are: damage to the oil seal lip during assembly, oil seal tilting and dry friction of the lip during operation. During the assembly of the oil seal, if a simple tool is used, or even the oil seal is directly installed without a tool, the oil seal lip is easily damaged, and the damage will gradually expand during future operation, causing oil leakage; at the same time, if the oil seal is installed crookedly, the oil seal lip will not work normally, causing lubricating oil leakage.

Optimizing the oil seal assembly process mainly involves adjusting the matching relationship between the pressure sleeve, oil seal, fixed sleeve and hollow shaft, and using D-mounting equipment to ensure good consistency in the oil seal position.

b) Improve the shaft of the reducer

The main reasons for reducer oil leakage due to shaft factors are improper shaft processing technology, insufficient shaft hardness and improper shaft tolerance selection.

The shaft processing methods include fine grinding, emery paper polishing, lathe finishing, super finishing and roller finishing. Among them, fine grinding is the most suitable processing method. The hardness of the contact part between the shaft and the oil seal lip is maintained between 50 and 60HRC; the shaft tolerance is generally selected between d9 and h9.

（3) Prevent foreign matter from entering the oil seal lip

To prevent foreign matter from entering the oil seal lip, the main protection measure for the high-speed shaft oil seal is adopted. In addition, after long-term operation and use, particulate impurities are easily accumulated at the bottom of the reducer. Once these foreign matter enter the oil seal lip, they will accelerate the wear of the oil seal lip and the shaft, causing leakage. For the particulate impurities inside the reducer, the improved design is to set magnetic steel around the oil seal, and the magnetic steel is fixed on the oil drain plug to absorb the metal impurities inside the reducer.

d) Prevent the sealing cover from popping out

The main reasons for the sealing cover popping out and leaking oil are excessive pressure inside the reducer and improper selection of the sealing cover hole tolerance. It is recommended that the sealing cover hole tolerance be selected within the range proposed by the sealing cover manufacturer.

The internal pressure of the reducer is the main reason for the sealing cover to pop out. The internal pressure is usually the pressure generated by the height of the lubricating oil and the heat of the reducer, and the pressure generated by the poor exhaust of the breather. Generally speaking, the reason for the poor exhaust of the breather can be solved by improving the breather structure, and the most effective way to solve the sealing cover popping out is to improve the sealing cover's anti-pop-out ability.