Seal friction, especially crawling seals hysteresis phenomenon can be caused by changing the chemical composition influence on purpose. In the process of changing the seal material, the design must firmly grasp the seal wear and extrusion properties change.

Seal manufacturer request to increase efficiency and system availability at the same time has good environmental performance. This requirement can be met through a variety of ways, one way is by changing the chemical composition of seals to improve their tribological properties and improve the overall efficiency of the system. Exposed to dynamic loading of the seal also plays a more difficult task - as much as possible to extend the service life of lubricating oil film to reduce friction and avoid seal leakage. If the seal friction is too large, there will be uneven movement, resulting in serious crawling seals and stick-slip phenomenon. In addition, manufacturers are now more inclined to use seals for use in low viscosity media materials and thermoplastic elastomer material, so when the seals to withstand high pressure and high temperature load or reboot after running idle for a long time is very prone to crawling phenomenon. If the cylinder back to work after the shutdown are often the driving force will be due to the lower can not function properly.

Optimization of friction seals

Almost all the materials and thermoplastic elastomer material of the seal will appear larger in the rest after the static friction. Static friction caused by a variety of reasons, but the main reason lies with the material itself. In addition, the seal lip seal geometry changes on the reaction direction of motion and lubrication sliding surface of the material and also the size of the static friction has a greater impact.

Friction optimized seals main purpose is to reduce equipment downtime and re-start when the required power and reduce the variety of conditions from run-time dynamic seal friction. After several tests, obtaining a large number of common seals of hydraulic and pneumatic seals friction properties of materials, lubrication material and information between the sliding velocity, and its feedback to the seal manufacturer. In addition, seal manufacturers can also be learned from research and development center seal on seal geometry and dimensions, and physical boundary conditions, such as surface material, pressure and temperature information. Conducting the tests, Research Center seal geometry of the standard size of the friction and wear of different materials for the basic performance of the test, the most important is the static coefficient of friction of different materials and the sliding friction coefficient. This article will use the TPU thermoplastic polyester materials testing to explain the whole process. TPU polyester materials according to their molecular structure can be divided into two types of polyester-based and polyurethane-based polymer materials. Static friction coefficient test show a significant static coefficient of friction and hardness, basic materials, polymeric agents and filling materials used in the relationship between species.

Friction and pressure was proportional to the change

Hydraulic rod seals in the tests conducted, the seals did not directly come to the hardness and the relationship between the static friction coefficient. But during all the experiments there is a common feature, namely, friction will increase as the pressure increases. When the friction increased to "deformation pressure", that is entirely fitting seal when the piston rod will not increase. Deformation pressure of the size and seal materials related. With the temperature increasing, the crawl will be more severe. Experiment proved that, with TPU P5001 materials resistance to low temperature creep properties of U-shaped ring the best. This seals in the piston speed is less than 0.03m / s to appear more pronounced when crawling. If a lower coefficient of friction material to add P5080 antifriction polymer materials with better performance, even at very high pressure is also able to demonstrate its standard P5001 and P5008 than smaller friction material, and the creeping trend also significantly reduced. Made use of this material has been successfully used to seal various industrial fields, such as convertible roof liner seal. Optimization of material Seals R & D is only a very small part of its structural design has been optimized to complement and support, has also been supported by finite element method.

Improved through the seal material can be a purpose of the seal friction and creepy performance influence; but in the process of sealing material improvements in the material should also be considered to improve the wear resistance and extrusion properties. Panacea for all the work of the seal material does not exist. Sealing materials based on solid knowledge and understanding of rising, through sealing material composition on the "Edit" to adapt to different circumstances. Design and production and processing in the appropriate technology in cooperation with, and soon there will be new and unique properties of the seal material successfully developed and put into production.