The common seal of construction machinery is the seal ring, also known as oil seal. It can isolate the oil and prevent the oil from overflowing or passing through. Because the service life of the seal is relatively short, the oil seal replacement frequency is high. During the use of construction machinery, the oil seal in use may always leak oil. This article will summarize several causes of oil seal leakage for reference only.
1. Assembly reason
Due to the press fitting tooling, the oil seal is deformed after press fitting. During assembly, the oil seal is scratched at the lip due to the thread or spline. Due to the low roughness of the oil seal position and the excessive pressing force, the spring fails or the lip turns over.
2. Skeleton reason
Due to the material and manufacturing problems of the oil seal spring, its performance fails. The failure form of spring is too tight or too loose. When it is too loose, the pressing force of the spring is small, and the sealing effect cannot be achieved. When it is too tight, the pressing force of the spring is large, and the oil seal and the rotating shaft are not properly matched. Resulting in abnormal wear of oil seal and oil leakage.
3. Working medium reason
The working medium is oil. The oil seal material shall be selected in consideration of its compatibility with oil. The compatibility of the two is poor, which will cause lip swelling, hardening, softening, cracking, etc., and eventually oil leakage.
4. Causes of lip wear
Including cleanliness issues such as casting sand, machining iron chips, oil impurities, etc. A large amount of oil is accumulated at the lip of the oil seal, and abnormal wear occurs during operation. The oil seal position is different from that of the rotating shaft. After the oil seal is pressed and assembled, the oil seal is eccentric worn and the lip is abnormally worn. The lithium grease at the oil seal lip is poorly lubricated, and dry friction will occur, resulting in abnormal wear.
