- When the O-ring is in contact with the chamfer of the internal cavity, the local stress of the O-ring will increase suddenly, causing the O-ring to have a strong tendency to be squeezed into the gap. Once the O-ring is squeezed in Shear damage will occur in the gap, which will seriously damage the sealing performance of the O-ring seal, and even lead to seal failure.
- When the contact pressure is greater than a certain critical value, the O-ring will be quickly squeezed into the gap at the chamfer, and there will be a large stress concentration at the chamfer, which is enough to destroy the integrity of the O-ring. In order to avoid this kind of damage to the sealing performance, it is necessary to add a retaining ring at the chamfer to improve the local stress situation.
- The retaining ring is usually made of polytetrafluoroethylene material. The elasticity, rigidity and strength of this material are very suitable for use as a local force member. It is made into a 2nmm thick sheet and placed in the opposite direction of the O-ring contact with the fluid. The inner wall is chamfered. At this time, the distance between the cavity 2 side can be appropriately increased to ensure good contact between the retaining ring and the O-ring seal, and the retaining ring will isolate the contact between the O-ring seal and the groove wall, and the retaining ring is directly connected to the groove wall. The bottom surface of the groove is in contact with the upper surface of the groove wall.
- Due to the bearing effect of the retaining ring, the original excessively concentrated stress is dispersed. Even at two right angles, the stress is far below the critical point value. It can be seen that increasing the retaining ring can improve the force of the O-ring seal , Improve sealing stability.