With the increasingly harsh conditions of the use of mechanical products, higher requirements for the use of rubber sealing products are required. The use of rubber seals
in aerospace, oil and mining industries, construction machinery and transportation industries, and energy industries often adapt to a wide temperature environment and harsh
environment such as high pressure sand and dust. According to the 1984 International Rubber Conference information, the using conditions for lip-type packing of rotation axis in automobiles and tractors have grown considerably. Due to the changes of usage conditions, the consumption of special rubber will increase continuously, and new types of seals will be required to improve the service life and reliability of the seals. The system pressure of the reciprocating dynamic seals is generally below 20MPa. The system pressure of high performance combination seal used in the aerospace and aviation industries can reach 56 MPa. At this point, the maximum operating speed is 1m/s. With the development of China’s economic construction, the requirements for the development of seals used in environments such as alpine, desert and underwater have been proposed. Extrusion seals: extrusion seals, especially O-rings, have always been widely used in seals. Other types such as X-type, T-type, D-type, square, triangular and other types, are suitable for different applications. The direction of improvement is to make its sealing performance stable and reliable, improving its pressure resistance and reducing friction. So that it can also be combined with low friction plastics such as polytetrafluoroethylene, nylon slip ring and support ring to form a combined seal. Improve its pressure resistance and reduce friction. Some manufacturers have licensed products at the speed of 7.5m/s and seal pressure of 5.6MPa.
Reciprocating lip seal: The reciprocating lip seal, which is also known as lip liner or seal cup, is widely used for hydraulic seals in hydraulic systems. This sealing surface is lip-shaped, with minimal interference during installation, making the lip fully in contact with the sealing surface to produce a sealing effect. When the oil cylinder is working, its contact force and contact area increase as the pressure increases, so that the sealing ability is improved. In the return stroke of the cylinder, the pressure is low, and the contact area and friction are lower than the working stroke, so the respiration is generated and the lip is lubricated.