(1) Choose appropriate sealing material and hydraulic oil, as well as adaptability to working temperature and compatibility with oil.

(2) The geometric position accuracy (concentricity) of the sliding parts relative to the sealing element is high, and the material is good (such as hard chromium plating) and the surface roughness is fine, which can extend the service life.

① For oil seals used in hydraulic pumps and motor journals, not only is the roughness of the sliding surface required to be within 0.25m Ra, but also hard chromium plating is required on its surface. During specific use, it is necessary to adjust the radial spring force of the oil seal lip according to the specific situation to make it moderately loose. Additionally, during installation, an installation sleeve or thin gasket should be used to protect the sealing ring to prevent the lip from curling or twisting, causing the spring to slide out.

② The commonly used rolling processing method for the inner surface of hydraulic cylinder not only improves surface roughness, but also makes its surface undergo cold work hardening treatment, which is beneficial for extending the service life of the sealing ring. In addition, the pressure used, the length and type of sliding surface also have a significant impact on the service life. Therefore, the "scheduled inspection" time should be determined based on these conditions.

③ The sealing surface is required to be in good lubrication condition to prevent dirt from invading. The use of oil that meets the specified cleanliness level and the correct installation method are also necessary conditions.