The coaxial sealing ring is a component developed in the early 1970s. After years of use and verification, it is widely used in the reciprocating motion sealing device of medium and high pressure hydraulic cylinders.

The coaxial seal ring for the piston is composed of a gray ring and an elastic rubber ring, which realizes two-way closure, and the coaxial seal for the piston rod has directionality. To prevent external leakage, it requires high tightness. The contact part is stepped and has cutting edges. The piston rod seal is called a stepped type. When stretching, due to the scraper action of the blade, the thickness of the oil film can be reduced. When shrinking, the closed inclined face The oil film can be protected by hydrodynamic action and sent back to the working steel to improve the closure and improve the lubrication conditions.

Gray rings and step seals used as sliding rings are made of polytetrafluoroethylene resins with different charges according to different conditions of use. Polytetrafluoroethylene hydrocarbon resin has a low coefficient of friction, is not easy to bond, and has self-lubricating properties, so the coaxial closure has the least frictional resistance in various reciprocating movements.

The elastic material is rubber, which can use a variety of cross-section forms, does not directly contact the sliding surface, does not require high mechanical strength, hardness, and wear resistance, and has a wide range of material choices.

The performance of the coaxial sealing ring for pistons is consistent with the precision of the sliding surface of the closed couple, and is closely related to the machining precision and surface roughness of the groove.

According to the high-speed and low-speed conditions of the rotating gray ring, and according to the cross-sectional size of the gray ring, one or two circular grooves are opened on the closed surface. The oil storage in the annular groove becomes a lubricating oil chamber that can reduce friction. The kinetics of oil accumulation in the rotating motion improves the sealing effect. The surface in contact with the rotating gray ring forms an arc along the shaft, which increases the contact with the O-ring and prevents the gray ring from rotating with the shaft. Its material is filled with polytetrafluoroethylene hydrocarbon and polyamide resin for high pressure. In the rotating grey ring, the external circular seal can be used, with lubricating oil, low friction, no stickiness, smooth start, wear resistance, and good dimensional stability.

Rotary gray rings are suitable for shafts, rods, pins, rotary joints, etc. that have rotating actions. They can withstand the pressure on both sides and the AC pressure, and work under the condition of moving speed without high pressure and tens of minutes. , such as automobile starters, central rotary joints of hydraulic loaders, etc.