Discussion on the Solution to Oil Leakage of Auto Transmission

With the rapid development of the auto industry, the output of the auto continues to rise. The gearbox is one of the important parts of the auto, which plays a vital role in the driving and handling of the auto. The quality of gearbox has a direct impact on auto performance.
Transmission oil leakage is a common failure of the transmission, and it is also the cause of early transmission failure.
One of the highest failure modes for long-term rework. Oil seal and bolt fastening oil leakage are the biggest problems in the transmission oil leakage problem. Solving these two problems will basically solve the transmission oil leakage problem.
Oil seal problem analysis
In fact, there is no problem with the selection of oil seals. Almost all of them are designed independently for the transmission, and the cooperation with various parts of the transmission can also meet the requirements. Oil seal leakage is mainly reflected in two aspects: early oil leakage from the oil seal, generally within 4000km, and part of the oil seal is found to be aging or falling off when the oil seal is in some unconventional working areas.
Transmission oil seal problem solving
In view of the early oil leakage of the oil seal, the following problems were found:
1. The oil seal is not stable when it is pressed, and the cooperation between the oil seal and the oil seal installation parts is not good enough.
And the lip is in poor contact with the part.
2. The mating part of the lip of the oil seal (such as the first shaft of the transmission), although it has been
It has been polished, but during the installation process, the oil seal has to go through some rough processing parts, and it is easy to scratch the lip of the oil seal if you are not careful.
3. The internal cleanliness of the transmission cannot meet the requirements, resulting in oil leakage from the oil seal.
To address these problems, the following improvements can be made:
1. In practice, through the improvement of the oil seal press-fitting tooling, all guide
Type tooling to ensure the stability of press-fitting.
2. Design the oil seal installation protective cover. Before the oil seal is installed in place, use the protective cover to protect the oil seal through the rough machining surface of the matching parts, so as to fully protect the oil seal from being scratched during the installation process.
3. Oil leakage caused by bolt tightening in the gearbox
In the bolt fastening process, some bolts are caused by problems such as changes in air pressure during assembly, causing the bolts to
The bolts did not reach the required torque; second, some bolts were reworked due to problems found in the transmission assembly process, and the spring washers were not replaced in time. After the second assembly, the anti-loosening effect was significantly weakened, and the bolt torque attenuation was very obvious. Improvements can be made to address these issues:
1. Add a barometer to the air pipe connecting the pneumatic torque wrench on site, and add an air pressure tank to ensure that the air volume at the assembly site is sufficient, and use an electric torque wrench or a fixed torque wrench before going offline to check the bolt torque and oil leakage faults. The method guarantees the bolt torque.
2. Change all the bolts that can be changed into hexagonal flange bolts, for space, etc.
For bolt spring washers that cannot be changed due to reasons, it is required to replace all spring washers with new spring washers after disassembly and assembly at the assembly site to ensure that the bolt torque does not attenuate.