Hydraulic Seal Knowledge
Sealing is a mechanism that prevents leakage of working medium (internal leakage and external leakage) and prevents foreign objects (such as air, dust and water, etc.) from entering hydraulic components and hydraulic systems.
Although seals are auxiliary parts in hydraulic equipment, the quality of the seal and sealing device is one of the keys that directly affects the normal operation of the hydraulic system. To a certain extent, the quality of seals has restricted the improvement of the performance and reliability of hydraulic components and hydraulic systems, the length of service life, and the impact on the grade and level of hydraulic equipment, and the key to participating in international competition. This is also the key to domestic competition. One of the main factors for the quality difference of external hydraulic components. Often the loss caused by the failure of an individual seal may be tens of millions of times the value of the seal itself.
Dust seal
Installed on the inner side of the hydraulic cylinder end cover, the main sealing lip is exposed to the air, and the sealing medium is dust, sand, rain, frost and other dirt attached to prevent external dust and rain from entering the seal mechanism and affecting the viscosity of the hydraulic oil And scratch the sealing lip of the internal seal.
Piston rod seal
Installed inside the dust-proof seal inside the hydraulic cylinder end cover, the function is to prevent the hydraulic oil from leaking out. One of the main pressure-bearing components is one-way pressure-bearing, with greater pressure, and direct contact with the hydraulic oil. It is required to have good pressure holding performance in a static state, high pressure bearing in motion, good sealing performance, small friction factor, and strong anti-extrusion ability.
Support ring
Installed inside the hydraulic cylinder end cover, the main function is to support the piston rod; prevent the uneven pressure of the rod seal caused by the non-vertical force of the piston rod, resulting in
Guide belt
Installed on the piston, the main function is to guide the piston to move in a straight line, prevent the internal leakage of the piston caused by uneven force, and reduce the service life of the seal. The service life of the guide belt and support ring directly affects the use effect and life of the piston seal and piston rod seal, so the requirements on the guide belt and support ring are also high, such as low friction coefficient, high hardness, and long service life.
Piston seal
Installed on the piston, the main function is to seal the gap between the piston and the cylinder, and prevent hydraulic oil from leaking. The piston seal is the main seal in the hydraulic cylinder, bearing pressure in both directions, and is one of the most important seals that the hydraulic cylinder can withstand the pressure value. The main requirements for piston sealing are good sealing effect, good pressure holding effect under static state, strong pressure bearing capacity during movement, anti-extrusion, low friction coefficient, long service life, etc.
Static seal
The static sealing ring of the end cover is installed at the contact position between the outer circle of the end cover and the inner wall of the hydraulic cylinder; the static sealing ring of the piston is installed between the piston and the piston rod.
They are all static sealing rings in hydraulic cylinders. The static seal of the end cover prevents the hydraulic oil from leaking from the gap between the end cover and the cylinder barrel. It is pressure-bearing on one side. It is required to have strong anti-extrusion ability and good sealing effect; The seal is two-way pressure-bearing to prevent the hydraulic oil from leaking between the piston and the piston rod, and requires strong anti-extrusion ability and good sealing effect.
Rotating seal
It is installed on the shaft of the hydraulic pump and hydraulic motor to prevent the working medium from leaking out of the shell along the shaft and the external dust from intruding into the body.