In the research in the last century, there were obvious wear and local burning phenomena on the mechanical seal friction pairs of the rotating seals in the measurement of the characteristics of the rotating seal. Based on the same formula, the friction coefficient measured by the researchers equals 0.1 ~0.6. A series of experiments show that the leakage rate cannot be calculated by the formula of laminar flow in radial annular gap. Because only in the special cases, mechanical seals operate in liquid friction. They work mainly in the mixed friction and boundary friction. Due to the different values of the standards for leakage of mechanical seals, researchers put forward a standard value for them.
At present, the research work of rotary shaft seals abroad mainly focuses on the following aspects:
1. Intelligent sealing system. The EDV system developed by Hunger Company can monitor the wear of the seals at any time, and automatically adjust the interference amount through the external mechanism, thus restoring the sealing effect.
2. Multifunction of sealing device. For example, a car bearing uses a seal with inductive function, and uses the magnetic parts of the metal filler to compound the function of the active magnetic inductor into the seal, which can accurately measure the speed of the shaft.
3. Improvement of sealing material. Adopt new sealing material or improve the strength, wear resistance, heat resistance and dimensional stability of materials by various means.
4. Magnetic fluid seal technology. It is mainly used for rotary dynamic seals and reciprocating dynamic seals. At present, it is widely applied to drive shaft of computer hard disk, to avoid the harm of bearing lubricant, water and dust to the hard disk. Another successful application of magnetic fluid seals is vacuum equipment, in which the vacuum dynamic seal of the rotating shaft or swing rod has reached the level of standardization and generalization.