Material Selection Of Dustproof Sealing Ring

The oil seal can be used as a dust seal, but in a dusty working environment or to protect other seals, it is often necessary to use a special dust seal.

Most of the dust-proof sealing rings of hydraulic machinery and equipment are made of rubber, and most of the pneumatic machinery and equipment are made of felt material sealing rings (square or trapezoid). Aircraft and hydraulic cylinders working in cold regions use metal materials to remove the ice on the outside of the piston rod. Dust-proof sealing ring, the chemical department also chooses metal dust-proof sealing ring to prevent sticking on the piston rod.

Square or trapezoidal dust-proof seals belong to packing seals in terms of sealing mechanism. The dust-proof ability is related to the tightness of the contact surface. The tighter the contact, the better the dust-proof ability, but the greater the frictional resistance. The wedge-shaped dust seal is actually no different from the lip seal, and relies on the contact force of the lip tip to scrape off dust and dirt. Its frictional resistance is small, and the angle formed by the sealing lip tip and the shaft surface has a great influence on the sealing performance and wear and its dustproof efficiency. When the lip tip is outward, the included angle can be satisfied as long as it is greater than 4°, and when the lip tip is inward, the dustproof effect is not good.

The contact state of the sealing lip with the shaft surface also directly affects the dustproof effect and the wear of the sealing lip. There are several common contact situations. Among them, in normal contact state, the oil film is thin, the dustproof effect is good, and the wear is less; The tip is raised, which not only makes the dustproof effect, but also has a large frictional resistance. The contact of the lip tip is insufficient, and the friction is not large, but it cannot be dustproof; the contact angle of the lip tip is too large, the dustproof effect is short, and it is easy to wear and cause serious leakage. The reason for the oil.

Dust seals are important for protecting critical hydraulic equipment components. The infiltration of dust will not only wear the seals, but also cause the wear of the guide sleeve and the piston rod. The impurities enter the hydraulic sealing medium, which will also affect the function of the operating valve and the pump. In bad cases, these devices may also be damaged. The dustproof sealing garden can remove any dust on the surface of the piston rod, but does not damage the oil film on the piston rod, which is also beneficial to the lubrication of the sealing ring.