The main reasons for oil leakage in the manual forklift bulldozer reducer include pressure difference, unreasonable structural design, excessive fuel consumption, improper installation and maintenance processes, and improper oil selection. To address these reasons, the following corresponding measures can be taken:

Reasons for oil leakage

The pressure difference generated inside and outside the gearbox: In a closed gearbox, each pair of gears generates heat when they mesh and rub against each other. As the operating time increases, the temperature inside the gearbox gradually rises, while the volume inside the gearbox remains unchanged. Therefore, the pressure inside the gearbox increases, and the lubricating oil inside the gearbox splashes and spills onto the inner wall of the gearbox. Under the pressure difference, the lubricating oil leaks out from the gaps.

Unreasonable structure design or processing problems of the reducer:

The designed gearbox does not have a ventilation hood or a vent plug on the peephole cover, resulting in an increase in pressure inside the box.

The design of the shaft seal structure is unreasonable, such as using an oil groove or felt ring shaft seal structure. Due to the poor compensation performance of the felt, the seal fails in a short period of time.

Although there are oil return holes on the oil groove, they are prone to blockage, making it difficult to fully utilize the oil return function.

During the manufacturing process, castings were not annealed or aged, and internal stresses were not eliminated, resulting in deformation and gaps, leading to oil leakage.

There are defects such as sand holes, slag inclusions, pores, and cracks.

Oil leakage caused by poor machining accuracy may occur due to factors such as low machining accuracy, inappropriate tolerances, and assembly not meeting requirements on the mating surface of the gearbox body.

Excessive oil filling: During the operation of the gearbox, the oil pool is stirred vigorously, and lubricating oil splashes everywhere inside the machine. If the oil filling is too high, a large amount of lubricating oil will accumulate at the shaft seal, joint surface, etc., leading to leakage.

Improper installation and maintenance processes:

Oil leakage caused by low installation accuracy. The reducer is subjected to a huge dynamic load during startup. Once the installation accuracy of the reducer does not meet the standard requirements, it will cause the bolts of the reducer base to loosen, thereby exacerbating the vibration of the reducer, increasing the wear of the sealing rings at the high and low speed shaft holes of the reducer, and causing lubricating oil to flow out.

During equipment maintenance, oil leakage can also occur due to incomplete removal of dirt on the joint surface, improper selection of sealant, reverse installation of sealing components, and failure to replace sealing components in a timely manner.

Improper selection of oil: The lubricating oil for the gearbox should be selected based on conditions such as load, speed, and temperature. It is not right to blindly pursue a higher viscosity of the lubricating oil.

treatment method

Improve breathable cap and inspection hole cover:

Develop an oil cup style breathable cap and replace the previously thin inspection hole cover with a 6mm thick one. Weld the oil cup style breathable cap onto the cover with a 6mm diameter breathable hole to facilitate ventilation and achieve pressure balance between the inside and outside of the machine.

When refueling, refuel from the oil cup without opening the inspection hole cover plate, reducing the chance of oil leakage.

Optimize the oil seal assembly process:

When assembling oil seals, specialized tools should be used to avoid damage or tilting of the oil seal lip.

Before assembly, apply an appropriate amount of lubricating grease to the shaft and lip to reduce friction and wear.

Improve the design and processing of the shaft:

Ensure that the machining process of the shaft is reasonable, the surface roughness is moderate, and avoid problems such as burrs and improper chamfering.

The hardness requirement for the contact part between the shaft and the oil seal lip is between 50-60HRC. If the hardness is too low, the shaft is prone to wear; The hardness is too high and the economy is poor.

The tolerance of the shaft is generally selected between d9 and h9. If the tolerance is too small, the pressure between the shaft and the oil seal lip is too low, which can easily cause leakage; If the tolerance is too large, the pressure between the shaft and the oil seal lip will be high, and wear will also intensify.

Adopting new sealing materials:

For the leakage of the static sealing point of the reducer, a new type of polymer repair material can be used to block it.

If there is oil leakage at the static sealing point during the operation of the reducer, surface engineering technology can be used to use emergency repair agents to block the oil surface.

Seriously implement the maintenance process:

During the maintenance of the gearbox, it is necessary to carefully follow the process regulations. The oil seal should not be installed backwards, the lip should not be damaged, the outer edge should not be deformed, and the spring should not fall off.

The joint surface should be cleaned thoroughly, the sealant should be applied evenly, and the amount of oil added should not exceed the scale on the dipstick.

Regularly wipe and clean oil stains:

The static sealing point of the reducer can generally achieve no leakage or seepage through treatment.

However, due to aging seals, poor quality, improper assembly, and high surface roughness of the shaft, the dynamic sealing points may experience slight leakage.

Due to the poor working environment, dust adheres to the shaft and becomes oily, so it is necessary to wipe off the oil stains on the shaft after the equipment stops running.

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