What should I do if the slewing drive leaks?

Slewing drive is also called slewing reducer and slewing spur gear drive. Slewing drive oil leakage often occurs during the operation of the equipment, but there are many reasons for the oil leakage, and the solutions are also different. So what should I do if the slewing drive leaks gear oil? The following is a brief introduction by the slewing drive manufacturer on the cause and solution of the oil leakage of the slewing drive.

Reasons for gear oil leakage in slewing drive

HSE Slewing Drive Gearbox

1. The pressure difference between the inside and outside of the slewing drive

In a closed drive, each pair of gears meshing and friction will generate heat. According to Boyle Mario’s law, as the operating time increases, the temperature in the slewing drive box gradually rises, and the volume in the reducer box No change, so the pressure in the box will increase accordingly, and the lubricating oil in the box will be splashed and spilled on the inner wall of the reduction box. Due to the relatively strong oil permeability, under the pressure in the tank, where the seal is not tight, the oil will seep out from there.

2. The design of the slewing drive itself

The designed reducer has no ventilation hood or no breather plug on the peephole cover; the shaft seal structure design is unreasonable, and the oil groove and felt ring shaft seal structure is adopted. The compensation performance of the felt is extremely poor, which causes the seal to fail in a short time. ; Although there are oil return holes on the oil ditch, it is very easy to block and the oil return effect is difficult to play.

During the manufacturing process, the casting has not been annealed or aging treated, and the internal stress of the casting has not been eliminated, resulting in deformation and gaps resulting in oil leakage; there are defects such as sand holes, slag inclusions, pores, cracks, etc.; oil leakage caused by poor processing accuracy, due to deceleration The existence of factors such as low machining accuracy of the matching surface of the chassis body, improper tolerances, and non-conforming assembly requirements may cause the reducer to leak oil.

3. Excessive lubricating oil

During the operation of the slewing drive, the oil pool is greatly agitated, and the lubricating oil splashes everywhere in the machine. If the amount of lubrication is too much, a large amount of lubricating oil will accumulate on the shaft seal, joint surface, etc., resulting in leakage.

4. Insufficient installation accuracy

Oil leakage caused by poor installation accuracy. The reducer bears a huge dynamic load when it is started. Once the installation accuracy of the reducer does not meet the standard requirements, the base bolts of the reducer will be loosened, which will aggravate the vibration of the reducer and make the seal ring at the high and low speed shaft holes of the reducer. The wear is intensified, causing the lubricating oil to flow out. At the same time, when the equipment is overhauled, 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.

5. The lubricating oil model is wrong

Generally, the slewing drive often uses HJ-40, HJ-50 mechanical lubricants, and can also be lubricated with HL-30, HL-20 gear oils and HJ3-28 rolling machine oils. In short, the lubricating oil of the reducer should be selected according to the load, speed, temperature and other conditions. It is wrong to blindly pursue the viscosity of the lubricating oil, the better.

The solution to the leaking gear oil of the slewing drive

1. Improve the breathable cap and inspection hole cover

Aiming at the problem of oil leakage of the slewing drive caused by the pressure difference, it can be solved by improving the vent cap and the inspection hole cover. Although the reducer has a vent cap, the vent hole is too small, and it is easy to be blocked by dust and oil. In addition, the inspection hole cover must be opened every time the oil is refilled, and opening once will increase the possibility of oil leakage, causing leakage in places that did not leak. To this end, an oil cup-type vent cap can be made, and the original thin inspection hole cover is changed to 6mm thick, and the oil cup-type vent cap is welded to the cover plate. The diameter of the vent is 6mm, which is convenient for ventilation and makes the machine The internal and external pressures are balanced. When refueling in the future, you can directly add oil through the oil cup without opening the inspection hole cover to reduce the chance of oil leakage.

2. Unblock the lubricating oil return channel

The oil spilled on the inner wall of the box should flow back to the oil pool as soon as possible, and do not store it in the shaft head seal to prevent the oil from gradually leaching out along the shaft head. For example, an oil seal ring is designed on the shaft head of the reducer, or a semicircular groove is glued to the upper cover of the reducer at the shaft head, so that the oil splashed on the upper cover flows to the return pool along both ends of the semicircular groove.

3. Improve sealing materials

(1) Slewing drive shaft seal with output shaft as half shaft Improved belt conveyor, screw unloader, impeller coal feeder and other equipment. The output shaft of reducer is half shaft, which is more convenient for modification. Disassemble the reducer, remove the coupling, take out the shaft seal end cover of the reducer, machine the groove on the outer side of the original end cover according to the size of the supporting frame oil seal, install the frame oil seal, and the side with the spring is inward. When reinstalling, if the end cover is more than 35 mm away from the inner end surface of the coupling, a spare oil seal can be installed on the shaft outside the end cover. Once the oil seal fails, the damaged oil seal can be removed and the spare oil seal can be pushed into the end cover. Eliminate the time-consuming and laborious processes such as disassembling the reducer and disassembling the coupling.

(2) The output shaft of the reducer shaft seal of the entire shaft is improved. The output shaft of the reducer of the entire shaft transmission has no coupling. If the above scheme is modified, the workload is too large and unrealistic. In order to reduce the workload and simplify the installation procedure, a split-type end cover was designed, and an opening-type oil seal was tried. The outer side of the split end cover is machined with grooves. When installing the oil seal, first take out the spring, saw the oil seal into an opening, and sleeve the oil seal on the shaft from the opening, butt the opening with adhesive, and then install the opening upward. Put on the spring and push in the end cap.

4 Using polymer composite materials

Polymer composite materials are based on high molecular polymers, metal or ceramic ultra-fine powders, fibers, etc., which are composited under the action of curing agents and curing accelerators. Various materials complement each other in performance and produce a synergistic effect, so that the comprehensive performance of the composite material is better than that of the original composition material. With strong adhesion, mechanical properties, and chemical corrosion resistance, it is widely used in the repair of mechanical wear, scratches, pits, cracks, leakage, casting sand holes, etc. of metal equipment, as well as various chemical storage tanks , Chemical anti-corrosion protection and repair of reaction tanks and pipelines.

For the leakage of the static sealing point of the slewing drive, the polymer composite material and technology can be used to control the leakage on the spot. There is no need to disassemble, and the polymer composite material is used to control the leakage externally, which saves time and effort, and the effect is immediate. Oil resistance and 350% stretch, overcoming the influence of the vibration of the reducer, has well solved the problem that the company has not been able to solve for many years. If the static seal point of the reducer leaks oil during operation, the oil surface emergency repair agent of surface engineering technology can be used to stick the plug, so as to achieve the purpose of eliminating the oil leakage.

5. Improve the maintenance process

During the overhaul of the slewing drive, the process regulations must be carefully implemented. The oil seal must not be installed reversely, the lip must not be damaged, the outer edge must not be deformed, the spring must not fall off, the joint surface must be cleaned, the sealant must be evenly applied, and the amount of oil must not exceed the scale of the oil dipstick.

6. Do a good job of cleaning

The static sealing point of the slewing drive can generally be leak-proof through treatment. However, due to the aging of the seals, poor quality, improper assembly, and high surface roughness of the shaft, the dynamic sealing points will cause small leakage at individual dynamic sealing points. Due to the poor working environment of cement companies, the dust sticks to the shaft and it is almost greasy. Therefore, it is necessary to wipe off the oil stains on the shaft after the equipment is stopped.

What to do if the gear oil leaks in the slewing drive From the above-mentioned reasons and treatment methods of oil leakage, the common oil leakage problems can basically be solved. We should pay attention to the maintenance and regular maintenance of the reducer when using the slewing drive in daily life, which can better prevent the occurrence of oil leakage, and at the same time extend the operating life of the slewing drive to ensure its good working condition.