Rotary shaft lip seal (referred to as: oil seal) is a high-tech precision rubber sealing part, it is through the flexible rubber (or leather, plastic, etc.) seal and shaft contact to prevent the leakage of lubricating oil or other media, as shown in Figure 1. The early oil seal is made of leather, after the second World War, the use of synthetic rubber production of oil seals gradually increased, especially in the past 20 or 30 years, due to the rapid development of machinery manufacturing, vehicles, aviation, aerospace and other industries, the oil seal has put forward high and low temperature resistance, high pressure resistance, special media resistance, to adapt to high-speed, vibration and prolong the service life and a series of harsh demands. Thus, the material, structure, performance test, quality control means and sealing mechanism of the oil seal are extensively and deeply studied, and the sealing performance and service life of the oil seal are greatly improved. In the early 1960s, the successful development of fluid power oil seals with reflux effect abroad made a great leap in the technology of oil seals, and solved the sealing problems of some very difficult sealing parts. In the 1980s, the United States produced a polytetrafluoroethylene oil seal, which is not only suitable for ultra-high speed, but also high and low temperature resistance, resistance to a variety of corrosive media, and suitable for occasions with dry friction. The implementation of the international standard for oil seals in the 1980s has made oil seals applicable and interchangeable in the world, and various countries have re-formulated new national standards with reference to international standards.
Rotate the mounting position of the seal ring
China started late in oil seal research, although there has been considerable progress in recent decades, but compared with the international level, there is still a big gap in product structure design, rubber matching technology, production technology, production equipment, mold processing, quality control means. At present, the production of oil seal in China is mostly distributed in small enterprises with relatively simple conditions. Backward production technology and equipment, coupled with the lack of sufficient understanding of the high technical content and high precision of the oil seal, the complexity of the technical performance requirements and the rigor of the process are insufficient, and the investment of the fund is insufficient, resulting in poor quality of the oil seal in China, unreliable sealing performance and short service life. The production level of most manufacturers only stays at the level of foreign countries in the 1950s and 1960s. Most of China's high-performance oil seals mainly rely on imports. On the other hand, due to the low quality of the oil seal, it also affects the competitiveness of China's mechanical products in the international market. Therefore, although the oil seal accounts for a small proportion in the entire machinery industry, it is a kind of precision rubber seal with wide service, wide influence and huge social and economic benefits in the rubber industry, which plays an important role in the development of the national economy, and its development should be highly valued.