Working principle of rubber O-rings
Thread Content
Various sizes of O-rings are used in units in general, so who can explain how O-rings work?
I guess it’s by its expansion that sealing is achieved. I have seen many “O”-ring seals, but I am thinking about their principle for the first time. I heard from the master that there are quite specific requirements for this sealing ring as well. There are many levels and types.
Isn’t it sealed by compression?
O-rings are rubber sealing rings with a circular cross-section; they are called O-rings because of their O-shaped cross-section, and are also known as O-type seals. Its material is mainly nitrile rubber or fluororubber. The O-ring primarily regulates the degree of sealing at the sealing surface through the thermal expansion and contraction of its own material.
The unit is sealed using O-rings in general, and one day a college student who had just started working there asked about the principle behind this, and it was actually difficult to explain to him.
Firstly, vulcanized rubber is elastic, and elasticity is the key factor that determines a rubber’s sealing performance. After the O-ring is compressed, the rebound effect endows it with sealing properties. But apart from elasticity, the most important parameter for defining an O-ring is compressive set. Generally speaking, under the same conditions, the lower the compressive set, the better the sealing performance. If the O-ring is to be used in complex environments, such as those with special media or extreme temperatures, it is necessary to consider whether the physical properties of the rubber compound will change under these conditions. If the change is significant, it may lose its sealing performance. Thermal expansion and contraction, as well as rubber swelling, are not beneficial for O-rings that are used over a long period of time.
Sealed tightly to the cover by compression and rebound