The influence factors of seal performance

There are many factors that can affect seal performance, generally includes the following 1) ten o 'clock The piston rod quenching hardness HRC55 - Thick 30-60, chromium plating layer 501 m, undirected grinding after the piston rod plating to eliminate grinding spiral line trace. 2) The speed of oil film thickness is associated with reciprocating movement speed. High speed oil film thickness, easy to leak; cattle producers. Low speed is less than 0. 5 m/s, the film too thin, increase friction, easy to produce 'crawl'. 3) Seal friction resistance and the moving parts of frictional resistance is changing. Startup frictional resistance (largest Dry friction) , when reach the appropriate speed, between the friction pair formed the continuous oil film, friction resistance, friction pair movement speed is too high, thickened oil film, the friction resistance increases. 4) The change of the temperature of the oil temperature effect on oil viscosity, oil film thickness and sealing performance. In order to guarantee the good performance of sealing, the hydraulic system working temperature should be 40 - stabilise 80C。 5) Cleanness of liquid claw oil pollution control is commonly NAS level, namely oil diameter & amp; 101 m dirt particles concentration will xiaoding 3 mg / 100 ml. 6) Contact pressure of contact pressure must be moderate, so as to cambium thin oil film in a row. If the contact pressure is too small, the oil film thickness, easy to leak; Contact pressure is too large, the oil film too thin, easy to cause dry friction, shorten the service life of seals. 7) Surface roughness of the piston and piston rod surface roughness generally 0. 8, the roughness of the seal installation groove, 1 side. 6, bottom R3. 8) Hydraulic cylinder hydraulic pressure causes the deformation of the seal to seal effect, but also increased the wear and tear, sliding surface cause fever, prompting system temperature and increasing sliding resistance. So we will strictly control pressure in the actual use. It is also a need to ensure that the service life of the seal. Such as 16 mpa seals are used in hydraulic system of 16 mpa for the service life of two years; If in 21 mpa in the hydraulic system is reduced to two months; Used in 31. 5 mpa used in the hydraulic system of life only for two days. 9) Medium to satisfy various requirements, hydraulic oil by adding different additives. The compatibility of additives sealing material and will produce great influence on service life and to choose the appropriate sealing material must be in accordance with the product. 10) Q gap mainly refers to the seal installation groove or seal fitting clearance of slide surface in low pressure side. Seal in the fluid pressure, will produce deformation and plastic flow, the seals have a tendency to be fitting clearance into the root. In order to ensure the performance, accuracy and life of the hydraulic cylinder, sealing structure often set the guide element. Before and after seal friction pair in the gap due to the pressure, the conditions, types of seals, and materials.