1. The piston and cylinder liner, also known as the piston seal, are dynamic seals. Generally, the Gly ring (combined seal) can achieve a pressure of up to 40MPa, with dual seals (even up to 60MPa when selecting different sealing materials to reduce clearance). The guide belt is used to support and guide both sides of the seal

2. Pistons and hydraulic cylinders are generally statically sealed, and a 20MPa O-ring is generally used for the following purposes. Above 20MPa, an O-ring with a retaining ring is used, and two retaining rings are added for double pressure. Of course, there are also dumbbell seals. The rectangular ring can withstand up to 50MPa of pressure

3. The seal between the guide sleeve and the hydraulic cylinder is a dynamic seal, that is, the rod seal is a dynamic seal, followed by a U-shaped ring and subjected to unidirectional pressure. Both are shared to ensure reliable sealing, with a pressure of up to 40MPa. The guide belts on both sides of the sealing are used for support and guidance

3. The fitting between the end cover, guide sleeve, rotary cover, and cylinder liner is a static seal. A 20MPa O-ring is generally used for the following purposes. Above 20MPa, an O-ring with a retaining ring is used, with double pressure and two retaining rings added. Of course, there are also dumbbell seals. The rectangular ring can bear up to 50MPa pressure

The cover must be equipped with a dust ring, dust proof, etc.

4. The tolerance of the inner hole of the cylinder liner is H8 level, the tolerance of the rod is f7 level, the piston and hydraulic cylinder H8/shaft f7, the sealing pipe groove bottom diameter hole H9, and the shaft is h9. Based on these sealing samples, the sealing of the guide sleeve and hydraulic cylinder is dynamic, with a clearance of generally 0.2-0.4mm. The greater the pressure, the smaller the clearance.

This is indeed a complex problem. Choose different sealing components for oil cylinders under different working conditions. The above are common. You can find sealing samples from different brands, such as Parker, Bose Charcoal Plate, NOK.MELKEL, and many others. Cylinder design is a process of accumulating experience and must be constantly explored.