The operating pressure of hydraulic cylinders is different. Generally, those below 16MPa are low-pressure cylinders, those between 16MPa and 25MPa are medium-pressure cylinders, and those above 25MPa are high-pressure cylinders. Polyurethane Y-type hydraulic oil seals are commonly used for low- and medium-pressure hydraulic cylinders, and combined oil seals can be used for high-pressure hydraulic cylinders. In addition, according to the speed of the piston movement in the cylinder barrel when the hydraulic cylinder is in use, the oil seal of polyurethane material should be selected for slow speed, and the hydraulic oil seal of hard material made of tetrafluoroethylene and copper powder should be used for fast speed.
There are many things that should be paid attention to when installing the oil seal of the hydraulic cylinder. For example: dustproof seals are divided into various types and sizes, including polyester oil seals and outer metal skeleton oil seals. Therefore, they are used in a wider range of applications. It is generally installed on the outside of the hydraulic cylinder end cover to prevent external dust, sand, rain, frost and other dirt from entering the inside of the sealing mechanism, contaminating the hydraulic oil, and even scratching the internal seals.
The main oil seal on the piston separates the A and B chambers of the hydraulic cylinder to prevent the two oil chambers from colluding with each other. The installation is relatively tight and you can use special tooling or tools. Smaller Gley rings should use split pistons.
The support ring is installed inside the guide sleeve of the hydraulic cylinder. Its main function is to support the piston rod and prevent the piston rod from being vertically stressed and causing uneven pressure bearing on the rod seal, resulting in poor sealing effect and short service life. The guide band is installed next to the oil seal of the piston so that there is no direct friction between the piston and the cylinder barrel, and friction is generated between the guide band and the inner surface of the cylinder barrel. Because the guide sleeve is generally made of soft and wear-resistant copper, tetrafluoroethylene and other materials, the hydraulic cylinder barrel is protected and the service life is extended. There are many forms of guide belts and support rings, and some are used in combination with the main seal. Installed on the piston, its main function is to seal the gap between the piston and the cylinder to prevent internal leakage of hydraulic oil. The piston seal is the main seal in the hydraulic cylinder. It bears pressure in both directions and is one of the most important seals that the hydraulic cylinder can withstand the pressure value. The main requirements for piston sealing are good sealing effect, good pressure maintaining effect in static state, strong pressure bearing capacity during movement, resistance to extrusion, small friction coefficient, long service life, etc. Advantages: excellent wear resistance, extrusion resistance, impact resistance, small compression deformation, wide adaptability, and easy installation. There are many cross-sectional forms and materials for piston rod seals, and different cross-sectional forms and materials are selected according to different working environments. There are various forms of piston seals, and the most appropriate form should be selected according to different usage environments.