The application function and basic classification of hydraulic seals

The use function of hydraulic seals and the basic classification. The use function of hydraulic seals. The leakage is extremely small. The leakage of hydraulic seals is extremely small. It has an outstanding sealing effect and actively improves its sealing effect as the pressure of the mechanical seal hydraulic oil increases. , Even in harsh working environments such as high pressure and high temperature, there is no significant increase in the leakage of hydraulic seals. Outstanding compatibility. Because hydraulic seals are immersed in hydraulic oil for a long time, mechanical seals are easy to swell, dissolve, or become embrittled and hardened, causing them to lose the sealing effect. Therefore, hydraulic seals are required to have outstanding performance in hydraulic oil compatibility. Small frictional resistance In order to prevent or reduce the occurrence of low-pressure creeping and other undesirable phenomena in hydraulic equipment, hydraulic seals are required to have low static and dynamic friction resistance, and their friction coefficient should be very stable. Long service life Hydraulic seals should have outstanding elasticity, heat resistance, cold resistance, pressure resistance, wear resistance and certain physical and mechanical strength, and have a long service life. Low-priced hydraulic seals should be easy to manufacture and install, and the corresponding sealing grooves are easy to process and manufacture, and the requirements for the processing accuracy of the seal surface are low, and the price is low. The basic classification of hydraulic seals ① UN series: UN type polyurethane oil seal is the most commonly used oil seal in hydraulic cylinders. It is a typical lip seal. It can achieve outstanding sealing function whether used for pistons or piston rods. Under the condition of low pressure, the U-shaped ring seals only by the interference deformation of the lip. With the increase of pressure, the elastic deformation of the lip increases, and the tension, contraction and bending stress increase, and the radial pressure of the U-shaped ring increases actively. The length of contact with the sealing surface is continuously added until the full axial length of the U-shaped ring touches the sealing surface, thereby ensuring excellent sealing performance under high pressure. UN is universal for the hole axis, its shape is symmetrical on both sides, it can accept the working pressure of 21mpa to 35mpa, and can withstand the temperature from -35℃ to 100℃. Made from M-90 materials. ② DH-type polyurethane oil seal The two-way effect of the pressure-proof sealing ring, on the one hand, scrapes off the dirt on the outer surface of the piston rod that moves inward, and on the other hand prevents the hydraulic oil from leaking in the cavity. No frame/double-effect compression ring, the data is M-90, the hardness is 90±2, and the temperature is -35 to 100°C. ③ D-1 type: D-1 type hole seal, its shape is short and thick on the outer lip, which is also classified as a kind of U-shaped ring. The pressure resistance can reach 40Mpa. It is often used in hydraulic cylinders. This kind of typical lip seal can achieve outstanding sealing effect when installed on the piston rod. It can accept the working pressure of 40Mpa, the operating temperature can reach -35 to 100 ℃, the movement speed is 0.03-0.5m/s, and it is made of M-95 raw materials. ④ Type D-2: Type D-2 polyurethane oil seal is a seal for shafts. Its shape is that the inner lip is short and thick, which is also a kind of U-shaped ring, with a pressure resistance of 40Mpa. Can accept -35 to 100 ℃. The moving speed is 0.03-0.5m/s, and it is made of M-95 raw material. ⑤ ME-1 series: It is a skeleton/dual-effect oil seal, the data structure is M-90 plus iron shell, it has anti-pressure effect, heavy load and auxiliary sealing, suitable for occasions with poor environmental conditions (such as outdoor, etc.). The moving speed of ME-1 is 0.03-1.0m/s, and the temperature resistance range is -35 to 100°C. ⑥ ME-2 series: ME-2 type polyurethane oil seal is a skeleton/reverse lip oil seal. Its raw material is M-90 plus iron shell, which has anti-pressure effect, strong heavy-duty scraping ability, and is suitable for harsh environments ( Such as mud/ash, etc.) occasions. The speed of ME-2 reaches 0.03-1.0m/s, and the working temperature is -35 to 100°C. ⑦ UPH series: The oil cylinder re-uses the hydraulic oil seal, which can be applied to the piston and piston rod seal. This seal has a large cross-section and can be used for large-scale operations. The nitrile rubber and fluorine rubber raw materials used ensure a wide range of operating temperature and a wide range of specifications. ⑧ LBH series: Reusable seal, which is a kind of seal that prevents dust from entering, protects the equipment and adheres to the sealing function. This is a kind of anti-scratch oil double-lip full rubber pressure-proof seal. Seals using nitrile rubber and fluoro rubber as materials are suitable for a wide range of operating temperatures. In addition to the most common hydraulic oil seals mentioned above, there are D-3 D-4 D-5 D-6 D-7 D-8 D-9 D-10 D-14 DH-03 DH-04 DH-05 DH -07 ME-3 ME-4 ME-5 ME-8 etc. Keywords: mechanical seals, mechanical seals