Generally speaking, natural rubber refers to solid latex obtained from rubber trees, which is cured, dried, etc. Natural rubber is a natural polymer compound with polyisoprene as its main component.

Physical properties of natural rubber. Natural rubber has high elasticity at room temperature, poor plasticity, very good mechanical strength, low hysteresis loss, low heat value in multiple deformation, so its bending resistance is also very good, and because it is non-polar rubber, the electrical insulation property is good.

Selection of suitable sealing material and hydraulic oil, as well as adaptability to working temperature and oil compatibility.

The geometric position accuracy (concentric degree) of the sliding part is higher than that of the seal (such as hard chromium plating), and the surface roughness is good in order to prolong the service life.

1 For hydraulic pumps, the oil seals used in the motor journal require not only the roughness of the sliding surface within 0.25 m of Ra, but also hard chromium plating on the surface. In the specific use, it is necessary to adjust the diameter of the lip edge of the oil seal according to the specific conditions. Apply spring force to make it elastic, and use sealing sleeve or thin washer to protect sealing ring during installation to prevent lip rolling and twisting, causing spring to slip out.

2. The inner surface of hydraulic cylinder is usually machined by rolling, which not only improves the surface roughness, but also makes the surface cold hardened, which is beneficial to prolong the service life of sealing ring. In addition, the pressure used, the length and type of sliding surface have a great impact on the service life. Therefore, the inspection time should be determined according to these conditions.

3. The sealing surface is required to be in a good lubrication state and prevent dust from invading. The use of oil that meets the required clean levels and the correct installation method are also necessary.