1. Hardness of O-ring The hardness of the O-ring materi […]
1. Hardness of O-ring
The hardness of the O-ring material is the most important indicator of sealing performance evaluation. o The compression amount determined by the hardness of the ring and the maximum allowable gap of the groove. Because A70 nitrile rubber seals can meet most of the conditions of use, the sealing material is generally provided with A70 nitrile rubber without special instructions.
2. Extrusion gap
The maximum allowable squeeze gap modulus and system pressure, o-ring cross section diameter and material hardness. Under normal circumstances, the higher the pressure, the smaller the maximum allowable modulus. If the gap g exceeds the allowable range, it will destroy the o-ring even.
3. To evaluate another index of o-ring seal, compress the selected material. Under pressure, as an elastic o-ring, it deforms elastically, and as the pressure increases, permanent plastic deformation occurs.
The O-ring is installed in the gutter to ensure its sealing performance, and the initial amount of compression should be allocated. For different applications, the amount diameter w relative to the prepress part is also different. Usually, the static seal is about 15%-30%, and about 9%-25% is in the dynamic seal.
5. Tension and compression
When the O-ring groove is installed, stretch or compress. If the value of tension and compression is too large, the increase or decrease will result in excessive o-rings, and the extension will reduce the cross-section diameter w 1% 0.5% accordingly. The hole sealing o-ring is under tension, and the maximum allowable extension is 6%; shaft seals, the best promotion of the o-ring, its circumference is compressed, and the maximum allowable circumference is compressed by 3%.
6. O-ring seals as O-rings can also be used as low-speed and rotating shaft seals for shorter operation. When the peripheral speed is less than 0.5 m/s and the O-ring can be selected according to the normal design standard, the peripheral speed is greater than 0.5 m/s, and the heat shrinkage of the rubber ring should be considered. Therefore, the sealing diameter is selected to seal 2% than the shaft diameter. Around, this phenomenon can be avoided. After the seal ring is installed in the groove, it will be radially compressed to cause the seal, and the o-ring groove is made of micro corrugated cardboard to improve the lubrication condition.