The leakage of the pipe joint in the hydraulic system can not be ignored, and the leakage can cause the efficiency to decrease, the oil temperature to rise, the actuator to be unstable, and the environment to be polluted. Directly affecting the normal use of hydraulic equipment, how to improve the sealing reliability of the joint body, is the subject that design and manufacturing enterprises and users have been facing. The ferrule type pipe joint has the advantages of simple structure, light weight, small volume, convenient use, no welding, and good pressure resistance, vibration resistance, heat resistance and reliable sealing.

After years of comparative trials and market research, it has been found that the single-edge ferrules designed and manufactured according to the national standard have the following problems:

1. The sealing reliability of the large-diameter ferrule is poor, especially the diameter of 28mm or more is not easy to use in the high-pressure pipeline.

2, the ferrule edge is easy to bite the wall.

3. During the assembly process, the arched portion is prone to yield, and the heat resistance and vibration absorption force are poor.

4. Repetitive assembly performance is poor. Through the analysis of the double-edged ferrule, the German double-edge progressive ferrule was fully tested and tested. It was found that the high-medium-pressure sealing reliability is higher than that of the domestic single-edge ferrule regardless of the large diameter and small diameter.

Taiwan's steel single-edge ferrule, hardened layer 35~45um, hardness 700HV, good toughness, core hardness 180HV. Comparison of the size design of several kinds of ferrules: The size design of the ferrules produced in China and Taiwan is generally the same, except that the inner diameter of the ferrules made in Taiwan is small, the double-edged ferrules are larger than the other ferrules, and the individual specifications are different. It is not interchangeable with domestic ferrules, but the strength cantilever of elastic deformation zone is better designed, which greatly improves the resistance to yielding. The double-edged progressive ferrule and one pre-formed deformation groove make the double-edged edge tightening more labor-saving, and when the double-edged edge is cut into a certain depth, the thrust ring restricts the cutting edge from excessively cutting into the outer wall of the steel pipe, ensuring cutting edge cutting At the same time, the depth of the elastic region is guaranteed to have high yield resistance, and the outer diameter of the outer diameter is different from that of the single edge.

The sealing principle of the sleeve type pipe joint: the right end of the ferrule is pressed under the top pressure of the nut, and the left end is squeezed into the gap between the taper hole and the pipe in the joint body. The right end of the ferrule is pressed under the top pressure of the nut, and the left end is squeezed into In the gap between the taper hole and the pipe in the joint body, the outer tapered surface of the ferrule is formed into a tapered surface contact seal, the inner cutting edge of the ferrule is embedded in the outer wall of the steel pipe, and a closed ring groove is pressed out on the outer wall of the steel pipe to cut into the seal to form a cone Face contact sealing, the inner edge of the ferrule is embedded in the outer wall of the steel pipe, and a closed ring groove is pressed out on the outer wall of the steel pipe to cut into the seal, and the nut is further tightened so that the middle portion of the ferrule is slightly convex, causing elastic deformation, reduction, low to passivation Click below. Stainless steel ferrules have poor corrosion resistance and can be rusted during storage. Therefore, the corrosion resistance of the Eo stainless steel ferrule is poor, and it can be rusted when stored. Due to the special surface treatment of the thread of the Eo nut, the joint body has less loss when the tightening torque is transmitted to the ferrule during assembly, and the special wear-reducing surface layer and the shallow hard surface layer are treated, so that the joint body is assembled. When the tightening torque is transmitted to the ferrule, the loss is small, and the layer design allows the ferrule to be smoothly cut into the steel pipe. The layer design allows the ferrule to be cut into the steel tube smoothly. Ordinary single-edge stainless steel ferrule 1Cr18Ni9Ti (304) cyanidation, the thread part is not surface treated, ordinary single-edge stainless steel ferrule, material 1Cr18Ni9Ti (304) cyanidation, the thread part is not surface treated, due to stainless 1.0 Therefore, the tightening torque cannot be effectively transmitted to the ferrule. The surface hardness of the ferrule cannot be high, and the friction coefficient of the steel to stainless steel is 1.0, so the tightening torque cannot be effectively transmitted to the ferrule. The surface hardness of the ferrule cannot be high, and the material and processing technology cannot be guaranteed. Only the depth of the hardened layer is lowered to avoid the false cut of the card sleeve. The material and processing technology can not be guaranteed, only the depth of the hardened layer is reduced to avoid the false cut of the card sleeve.

Further tighten the nut so that the middle part of the ferrule is slightly convex, and elastic deformation occurs. The elastic stress causes the right end surface of the ferrule to generate friction with the nut taper surface to prevent the nut from loosening, and the elastic deformation part can absorb the vibration in the hydraulic pipe. The vibration, the friction, to prevent the nut from loosening, the elastic deformation part can absorb the vibration in the hydraulic pipe, in addition, the tail of the ferrule also holds the steel pipe to form a collision seal. The tube forms a seal against the seal. The following is a further analysis of the sealing reliability of the single-edge ferrule and the double-edged progressive ferrule. The following is a further analysis of the sealing reliability of the single-edge ferrule and the double-edged progressive ferrule. The correct assembly of the ferrule fitting is also an important factor in ensuring the reliability of the joint body seal. The correct assembly of the ferrule fitting is also an important factor in ensuring the reliability of the joint body seal. Assembly notes for fittings:

Assembly notes for fittings:

(1) The perpendicularity of the end face of the steel pipe to the axis is less than 0.5.

(2) Deburring the end face, chamfering 0.2×450 to the end face burr.

(3) Apply a proper amount of grease to the threaded portion and the contact cone. Apply a proper amount of grease to the threaded portion and the contact cone.

(4) Install the ferrule, nut, and pay attention to the direction. Install the ferrule, nut, and pay attention to the direction.

(5) Grasp the steel pipe and make the end face against the joint body step. Grab the steel tube and place the end face against the joint body step.

(6) Draw a mark and tighten the nut. Draw a mark and tighten the nut.

(7) Ensure that the steel pipe does not follow the turn and screw it 1.3~1.5 turns to ensure that the steel pipe does not follow.

(8) Remove the nut and check the ferrule cut. Remove the nut and check the ferrule cut. (9) When pre-assembling and reassembling, the tightening torque is suddenly increased from the hand, and then tightened 600~900.

In summary, the leakage prevention and manufacturing quality of the ferrule type pipe joint (especially the design of the ferrule and the intrinsic quality of the ferrule), the accuracy of the steel pipe, in summary, the leakage prevention and manufacturing quality of the ferrule type pipe joint ( In particular, the design of the ferrule and the intrinsic quality of the ferrule) the precision of the steel pipe and the quality of the assembly are inseparable, requiring good cooperation between the manufacturer and the user.