First, clearance seal
The working principle is that there will be a little gap between the two moving parts, and the liquid friction resistance in the gap will prevent leakage. This method has some disadvantages, is only applicable to small hydraulic cylinder and the piston diameter and pressure between seal and advantage in order to improve the efficiency of the seal will leave a few groove on the piston, the groove will let the oil change in internal leakage path or truncate, in a small groove form vortex and produce resistance, and reduce the oil leakage; On the other hand, it is to prevent the offset of the piston axis, so as to maintain the clearance, ensure the lubrication effect, reduce the wear of the piston and cylinder wall, and increase the clearance sealing performance.
Two, the use of rubber sealing ring
Due to the different types of sealing rings in the hydraulic cylinder forgings, the sealing mechanism is not the same, and the O-type sealing ring mainly depends on the precompression amount to offset the gap to realize the sealing effect. And Y, YX, V shape depends on the lip of the sealing ring is deformed by the action of liquid pressure, so that the lip is close to the sealing surface and sealed. The higher the liquid pressure, the tighter the lip is affixed, and has the ability to automatically compensate after wear.
Three, the use of rubber seal components to achieve the sealing effect
This kind of seal is generally a combination type with the characteristics of two kinds of seals, which play a role in sealing together in the work. Take the Gretel ring, which is a combination of rubber O-rings and teflon Gretel rings. In the work, the good elasticity of O-type rubber ring is used to produce pre-and self-moistening property, so that it can be used in the hydraulic cylinder seal for a longer life.