1. Selection of forms for hydraulic seals
In hydraulic systems, common sealing forms include extruded O-ring seals, Y-rings, V-rings, and U-ring lip seals. Lip shaped sealing rings are mainly used for reciprocating dynamic seals. Compared with compression seals such as O-rings, reciprocating dynamic seals using lip shaped sealing rings have better comprehensive performance and longer service life. (Related reading: Sealing principle and model characteristics of lip shaped sealing rings)
The sealing pressure of the lip shaped sealing ring changes with the pressure of the medium. During work, the pressure of the medium should always be monitored to ensure sufficient sealing pressure without generating excessive friction. Squeezing sealing mainly relies on pre pressing force to generate sealing force, and the contact pressure of the sealing ring is pre-set, which cannot change according to the change of medium pressure during work. A large pre pressure will increase the contact area between the sealing ring and the sealing surface, resulting in significant frictional resistance. Excessive frictional force will cause damage to the sealing ring, making it difficult to start or causing crawling during low pressure. The lip shaped sealing ring can be stretched open through the lip to compensate for small wear and ensure sealing effectiveness and service life; As the friction margin decreases, the O-ring directly affects its sealing performance.
2. Material selection of hydraulic seals
The form and structure of seals have generally been finalized, and the quality differences among seals mainly lie in the materials used for production. The sealing materials mainly use rubber and synthetic resin. Due to the different performance characteristics of various materials, their applications also vary. When selecting, it is necessary to make appropriate choices based on different usage conditions and conditions. In addition, the sealing performance of a certain material on a sealed working medium (such as mineral oil) is good, while the performance on another medium is extremely poor, which is the compatibility between the sealing material and hydraulic oil. Moreover, various sealing materials exhibit different performance under different working conditions. Some are heat-resistant, while others are not; Some are acid resistant, some are alkali resistant, some are water resistant, and some are oil resistant; Some are resistant to heat, some are resistant to low temperatures, some are resistant to high temperatures, and so on. These factors need to be taken into consideration when considering sealing material.