Why is the O-ring compressed and deformed

Why is the O-ring compressed and deformed? The permanent deformation of the O-ring is caused by the following reasons:

1. Elements of O-ring shrinkage and stretching

The secret recipe of O-ring plastic particles is different, so the reduction and stretching of O-rings produced by different companies are also different. In the case of long-term shrinkage, the commodity can cause the imagination of reduced stress relaxation. This behavior will gradually expand with time. The longer the time, the smaller the shrinkage and tensile amount will be, so that its ductility is not enough, resulting in the emergence of leakage problems. The most immediate change method is to improve the cross-sectional specification of the commodity, but it will also expand the type of commodity structure.

2. Correlation between temperature and the whole process of O-ring relaxation

Temperature is the key to the relaxation of O-ring. No matter which vulcanized rubber material accelerates its embrittlement rate at high temperature. When the temperature in the natural environment is higher, the deformation of gas shrinkage will be greater. When the commodity deformation exceeds 50%, the O-ring will gradually lose its ductility and working ability, resulting in leakage. For example, when installing the O-ring, there will be the original in-situ stress, which will gradually subside due to the long-term relaxation of the sealing ring and the gradual reduction of the temperature. In some cases, it will subside with the significant reduction of the temperature. Even if the rubber material is temperature resistant, it is not easy to exceed 20% compared with the in-situ stress caused at 30 degrees, Therefore, when setting the original in-situ stress when installing the O-ring, the factor of temperature in the office environment should be considered.

3. Harm of material pressure to O-ring deformation

The working pressure of material is more harmful to the deformation of O-ring, which is the most common condition causing the deformation of O-ring in all loads. With the development trend of intelligent hydraulic press, the working pressure of hydraulic press material is increasing. The permanent deformation of O-ring will be caused in this kind of high-pressure working environment for a long time, and this kind of deformation is not reversible, Therefore, different materials should be used for different pressures, and the rubber material with relative breakdown voltage should be selected. Relatively, in order to solve the high pressure, the hardness of the sealing ring of the raw material of breakdown voltage will also be strengthened.

The working pressure of materials in work is the key factor causing the permanent deformation of O-ring. The pressure of contemporary hydraulic machinery is increasing day by day. Long term high pressure effect will cause permanent deformation of O-ring. Therefore, the design scheme should adopt appropriate breakdown voltage rubber material according to the pressure. The higher the pressure, the higher the strength and high pressure resistance of common raw materials.