According to the function, hydraulic dynamic seals can be divided into 5 categories. They are piston seal, piston rod seal, dust seal, rotary seal and wear ring (guide ring).
1. Piston seal
The role of the piston seal is to ensure that the liquid working medium in the hydraulic cylinder does not leak through the piston end. Piston seals usually include one-way seals and two-way seals. Unidirectional seal, that is, the pressure only acts on a single direction; Bidirectional seal, then the pressure on the reciprocating motion of the two directions.
2. Piston rod seal
Piston rod seal ring, also known as U cup, is the main piston rod seal, installed on the inside of the hydraulic cylinder end cover, the role is to prevent hydraulic oil leakage. Piston rod seals are made of polyurethane or nitrile rubber and in some cases need to be used in conjunction with a support ring (also called a retaining ring) to prevent the sealing ring from extruding under pressure.
3. Dust seal
Dust ring is installed on the outside of the end cover of the hydraulic cylinder to prevent external pollutants from entering the cylinder. According to the installation mode, it can be divided into clamping type and pressing type.
4. Rotary seal
Rotary seal is a kind of bidirectional sealing ring that can bear the pressure on both sides or alternating pressure. It is used to seal the rod, shaft, pin, rotary joint and other parts with rotating or swinging motion.
5. Wear ring (guide ring)
The guide support ring is installed on the end cover of the hydraulic cylinder and the piston to support the piston rod and piston and guide the piston to move in a straight line to prevent metal to metal contact. Installation of piston rods and pistons usually requires wear rings.
