Sealing method of hydraulic cylinder

The hydraulic cylinder needs to be sealed because of the problem of internal leakage and external leakage. When there is internal leakage and external leakage in the hydraulic cylinder, the volume of the chamber of the hydraulic cylinder will become smaller and the efficiency will become low, which will reduce the performance of the hydraulic cylinder in the work. If the situation is severe, the system pressure will not rise and will not work. At the same time, from the point of view of environmental protection, it is also necessary to avoid the occurrence of leakage, so it is very important to take the necessary sealing measures.

The main sealing parts in the hydraulic cylinder are piston, piston rod, end cap and so on. There are three sealing methods usually used in hydraulic cylinders, which is also the main purpose of writing this article today, to introduce several ways of sealing in hydraulic cylinders.

First of all, the first method used is called the gap seal, which works by retaining a little gap between the two moving parts, and the liquid friction resistance generated in the gap prevents leakage. This method has certain disadvantages, that is, it is only suitable for sealing between the hydraulic cylinder and the piston with smaller diameter and pressure. The advantage is that in order to improve the efficiency of this sealing, several grooves will be opened on the piston, and these grooves will change the path or cut off the oil when the internal leakage occurs, forming a vortex in the small groove and generating resistance, so that the amount of oil leakage is reduced; On the other hand, it prevents the offset of the piston axis, which is conducive to maintaining the matching gap, ensuring the lubrication effect, reducing the wear of the piston and the cylinder wall, and increasing the clearance sealing performance.

The other is the use of rubber sealing ring, due to the different types of sealing rings in the hydraulic cylinder, so the sealing mechanism is not the same, of which the O-ring mainly relies on the amount of pre-compression to offset the gap to achieve the effect of sealing. The Y, YX, V shape, etc. rely on the lip of the sealing ring to be deformed by liquid pressure, so that the lip is sealed tightly to the sealing surface, the higher the liquid pressure, the tighter the lip, and has the ability to automatically compensate after wear.

Finally, rubber sealing components are used to achieve sealing. Among them, there are mainly gray ring, ray seal, Sterseal, etc. This seal is generally a combination type with the characteristics of two seals, and plays a sealing role in the work. Take the Gray ring, which is made of a combination of rubber O-ring and a polytetrafluoroethylene gray ring. In the work, the O-type rubber ring is used to produce good elasticity and self-moistening, so that it can be used in the hydraulic cylinder seal longer life.