(1) Select the appropriate seal material and hydraulic oil, as well as the adaptability to the working temperature and the compatibility of the oil.
(2) The geometric position accuracy (concentricity) of the sliding parts relative to the seal is high, the material is good (such as hard chrome plating) and the surface roughness is fine, which can prolong the service life.
① For oil seals
used in hydraulic pumps and motor journals, not only the roughness of the sliding surface is required to be within Ra of 0.25m, but also the surface is required to be plated with hard chrome, and the diameter of the oil seal lip needs to be appropriately adjusted according to the specific situation. Adjust the spring force to make it tight enough, and use a mounting sleeve or a thin gasket to protect the sealing ring during installation to prevent the lip from rolling and twisting, causing the spring to slip out.
②The inner surface of the hydraulic cylinder is usually processed by rolling, which not only improves the surface roughness, but also makes the surface hardened by cold work, which is beneficial to prolong the service life of the sealing ring. In addition, the pressure used, the length and type of the sliding surface also have a great influence on the service life. Therefore, the "regular inspection" time should be decided according to these conditions.
③ The sealing surface is required to be well lubricated to prevent dirt from invading people. The use of fluids that meet the specified cleanliness levels and the correct installation method are also necessary conditions.