3 main reasons that cause reducers oil leakage

A reducer is a reduction transmission device commonly used between the prime mover and the working machine. It is very common in the mechanical and industrial fields. During the use of the reducer, oil leakage is a common fault that may occur. It not only causes waste of lubricating oil and affects the normal operation of the equipment, but may also pollute the working environment and even pose a threat to the safety of the equipment.

In more than 10 years of manufacturing and production of planetary gear reducers and double enveloping worm reducers, Shanghai SGR Heavy Industry Machinery Co.,Ltd. found that the main causes of reducer oil leakage can be divided into three categories: structural design and assembly problems, lubrication problems and pressure problems.

(1) Structural design and assembly issues that cause oil leakage

Structural design problems mainly refer to the unreasonable structure of the gear reducer itself, including:

a. The sealing requirements are not fully considered when designing the reducer, such as unreasonable design of the vent hole, insufficient oil return groove or unreasonable oil circuit design, which causes lubricating oil to accumulate and leak.

b. The hole cover of the reducer is too thin, which is easy to deform after tightening the bolts, making the joint surface uneven and causing oil leakage in the contact gap;

c. The castings of the reducer have not been annealed or aged, and the internal stress has not been eliminated, which will inevitably cause deformation, resulting in gaps and leakage.There is no oil return groove on the reducer housing, and the lubricating oil accumulates in the shaft seal, end cover, joint surface, etc., and leaks out from the gap under the action of pressure difference;

d. The problem of improper oil seal . In early times,reducers mostly used oil groove and felt ring shaft seal structures. During assembly, the felt was compressed and deformed, and the gap between the joint surfaces was sealed. Since the compensation performance of the felt was extremely poor, the seal failed in a short time. The oil return hole was easily blocked, and the oil return function was difficult to play.

e. Structural design and assembly problems: During the assembly process of the reducer, if the sealing surfaces of the housing, bearing seat, end cover and other parts are not machined with sufficient precision, with scratches or burrs, or the sealing ring is not installed correctly during assembly, or the pre-tightening force of the fasteners is uneven or too loose, it may lead to poor sealing and oil leakage;

(2) Lubrication problem that causes oil leakage

Lubricating oil is extremely important for reducers. Lubricating oil is not only a lubricant for the normal operation of reducers, but also a key factor in protecting reducers, improving efficiency and reducing maintenance costs. Improper lubrication may cause oil leakage mainly including:

a. Too much oil: During the operation of the reducer, the oil pool is stirred violently and the lubricating oil splashes everywhere in the machine. If too much oil is added, a large amount of lubricating oil will accumulate in the shaft seal, joint surface, etc., causing leakage.

b. Using the wrong type of lubricant will cause the pressure in the inner box to increase, causing the lubricant to overflow;

c. Improper maintenance process: When repairing the reducer, oil leakage may also occur due to incomplete removal of dirt on the mating surface, improper selection of sealant, reverse installation of seals, and failure to replace seals in time.

(3) Pressure difference problem that cause oil leakage

a. During the operation of the reducer, the friction of the moving parts and the influence of the ambient temperature cause the temperature of the reducer to rise. If there is no air vent or the air vent is blocked, the pressure inside the machine will gradually increase. The higher the temperature inside the machine, the greater the pressure difference with the outside world, and the lubricating oil will leak out from the gap under the action of the pressure difference.

b. Deformation of the housing or joint surface: Long-term overload operation of the reducer, impact load or uneven installation foundation may cause the housing to deform, resulting in the sealing surface not fitting tightly, forming a gap and oil leakage.

c. Pressure problem: The pressure inside the reducer increases due to temperature increase, poor ventilation, etc. If there is no suitable exhaust or pressure balancing device, the high pressure will force the lubricating oil to overflow from the weak seal.

In addition, SGR reminds you that if the reducer leaks oil during use, you should stop the machine immediately for inspection, find out the specific cause of the leakage and take corresponding repair or replacement measures to prevent the fault from expanding and causing greater losses.(Author: SGR, Angie Zhang)

Email: export@sgr.com.cn

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