Hydraulic seals are indispensable components in hydraulic systems, primarily used to prevent fluid leakage, maintain system pressure, and block contaminants from entering the system. They are widely employed in hydraulic cylinders, pumps, motors, and valves, significantly impacting the efficiency, reliability, and lifespan of hydraulic systems.
Hydraulic seals come in various types based on their function and application scenarios, including piston seals, rod seals, guide rings, support rings, wipers, and static seals. Piston seals are used between the piston and the cylinder bore to prevent fluid from leaking from the high-pressure side to the low-pressure side, with common types including U-cups, V-rings, and O-rings. Rod seals are used between the piston rod and the cylinder head to prevent fluid from leaking out of the cylinder, with common types including lip seals, combination seals, and Glyd rings. Guide rings and support rings are used to support and guide the piston and piston rod, preventing direct metal-to-metal contact and reducing wear and friction. Wipers are installed on the exterior of hydraulic cylinders to prevent dust, dirt, and other contaminants from entering the hydraulic system, thereby protecting internal seals and hydraulic fluid cleanliness. Static seals are used for sealing between fixed components, such as flanges, fittings, and valves, with common types including O-rings, flat gaskets, and metal rings.
The choice of materials for hydraulic seals is crucial, with common materials including rubber, polyurethane (PU), polytetrafluoroethylene (PTFE), and metals. Rubber materials such as nitrile rubber (NBR), fluorocarbon rubber (FKM), and silicone rubber (VMQ) offer excellent elasticity and wear resistance, suitable for various working environments. Polyurethane (PU) provides outstanding wear resistance and mechanical strength, making it ideal for high-pressure and high-load hydraulic systems. Polytetrafluoroethylene (PTFE) offers exceptional chemical resistance and low friction, suitable for high-temperature and corrosive media environments. Metal materials such as copper, aluminum, and stainless steel are primarily used for static seals and high-temperature, high-pressure environments.