The main factor of rubber O-ring damage is wear, and the degree of wear mainly depends on the size of friction.
When the liquid pressure is small, the size of the friction force of the rubber o-ring depends on the amount of pre-compression. When the working liquid is under pressure, the friction force increases with the increase of the working pressure. When the working pressure is less than 20MPa, the relationship is approximately linear. When the pressure is greater than 20MPa, with the increase of pressure, the increase of the contact area between the rubber O-ring and the metal surface is gradually slow, and the increase of friction is correspondingly slow. Under normal circumstances, the service life of the rubber O-ring will decrease approximately in a square relationship with the increase of liquid pressure. The increase in friction creates a lot of friction heat between the rotating or reciprocating shaft and the rubber O-ring. Because most O-rings are made of rubber, the thermal conductivity is very poor. Therefore, the friction heat will cause the aging of the rubber, resulting in the effectiveness of the O-ring, damaging its sealing performance. Friction can also cause surface damage to the O-ring, reducing the amount of compression. Serious friction will soon cause the O-ring surface damage, loss of sealing.
Now we can intuitively know that the friction of rubber O-rings to a large extent has a great impact on the service life of the O-ring, the friction of the O-ring affects the application, so do not ignore its friction when applying the O-ring.