Current Status Of Rotary Shaft Lip Seals
Rotary shaft lip seals (abbreviated as oil seals) are high-tech precision rubber parts. They prevent leakage of lubricating oil or other media through the contact between a flexible rubber (or leather, plastic, etc.) seal and the shaft, as shown in Figure 1. Early oil seals were made from shaped leather. After World War II, the use of synthetic rubber oil seals gradually increased. Especially in the last two or three decades, the rapid development of industries such as machinery manufacturing, vehicles, aviation, and aerospace has placed stringent demands on oil seals, including resistance to high and low temperatures, high pressures, resistance to special media, adaptability to high speeds and vibrations, and extended service life. This has spurred extensive and in-depth research into oil seal materials, structures, performance testing, quality control methods, and sealing mechanisms, greatly improving the sealing performance and service life of oil seals. In the early 1960s, foreign countries successfully developed hydrodynamic oil seals with a backflow effect, marking a significant leap in oil seal technology and solving sealing problems in some very difficult sealing areas. In the 1980s, the United States manufactured polytetrafluoroethylene (PTFE) oil seals, which are not only suitable for ultra-high speeds but also resistant to high and low temperatures, various corrosive media, and suitable for applications with dry friction. The promulgation and implementation of international standards for oil seals in the 1980s made oil seals more applicable and interchangeable worldwide, and various countries have formulated new national standards with reference to international standards.
