standard seals Mechanical and physical properties
Influence and Method of Hydraulic Oil on Seals
Hydraulic oil for the hydraulic drive system as a working medium, from the energy transfer, conversion and control role, but also plays a hydraulic system components of the lubrication, corrosion, rust and cooling and so on. The seal in the hydraulic system acts to prevent leakage of fluid from the joint surface, to maintain pressure, to maintain energy transfer or conversion.
At present, most of the sealing materials used at home and abroad are high molecular elastomers, and some special conditions also use plastic and various metals. But no matter what kind of material, should have the following performance:
1, with a certain degree of mechanical and physical properties: such as tensile strength, tensile strength, elongation
2, there is a certain degree of flexibility, hardness appropriate, and compression of permanent deformation is small;
3, with the working medium to adapt, not easy to produce swelling, decomposition, hardening
4, wear, have a certain tear resistance
5, with high temperature, low temperature aging performance.
However, without any sealing material, including all of the above properties, the need to work according to the environment, such as temperature, pressure, medium and movement to select the appropriate sealing material, and through the development of materials with the formula to meet certain requirements. Or use two or more materials composite or composite structure in the form of their own strengths, to achieve a more comprehensive effect.
Sealing effect formation: dynamic seal is divided into non-contact seal and contact seal. Non-contact seal is mainly a variety of mechanical seals, such as: graphite packing ring, floating ring seal, etc .; rubber composite seal and rubber and plastic combination seals are contact seals, relying on the pre-tightening force in the sealed cavity, Blocking the leakage channel and get the sealing effect. Hydraulic system seals are mostly static seal (end seal), reciprocating seal (piston, piston rod seal) and rotary seal.
Factors that affect the sealing effect: the choice of sealing structure and oil film formation, pressure, temperature, material compatibility, dynamic contact contact with the surface of the material, hardness, geometry, surface finish and so on.
First, the sealing material and hydraulic oil (liquid) compatibility: one of the sources of hydraulic oil pollution is the seal material and hydraulic oil does not adapt to the resulting "debris" or "debris." Seal due to "dissolved" damaged "debris" or "extracted" out of the combination of inorganic and fill reinforcement material, so that the seal damage and failure, while the formation of pollution of oil caused by hydraulic The oil is deteriorated.