A high-pressure self-tightening sealing structure and its use method

Abstract

The present invention discloses a high-pressure self-tightening sealing structure and a method for using the same. In the sealing structure, a cavity is provided inside the shell; the core shaft includes a large diameter section, a middle section and a small diameter section from bottom to top; the core shaft is provided with a gas passage; the flange is provided with a central through hole, and the lower end surface of the flange is provided with a flange. The method for using the present invention is as follows: a flexible sealing assembly is sleeved on the outer side of the middle section of the core shaft; the small diameter section of the core shaft is passed through the central through hole of the flange; the product to be sealed is placed in the shell cavity; the flange is fixedly installed on the upper end of the shell, and the outer surface of the flange flange, the outer surface of the flexible sealing assembly and the large diameter section of the core shaft are matched with the inner surface of the cavity provided in the shell from top to bottom; the clamping mechanism presses down the flange to achieve initial sealing; and the shell is pressurized to achieve pressurized sealing. The sealing structure of the present invention can be widely used in the field of sealing of high-pressure containers, and has the advantages of simple structure, reliable sealing, novel structure and strong adaptability.

Description

Technical Field

[0001] The invention relates to a high-pressure self-tightening sealing structure and a use method thereof, which are applied to the sealing of pressure vessels, in particular to the sealing of high-pressure and ultra-high-pressure structures, and belong to the technical field of sealing. Background Art

[0002] High-pressure vessels are widely used in aerospace, petrochemical and other fields. For high-pressure vessels containing toxic, harmful, flammable and explosive media, the reliability of the sealing structure is particularly important. Compared with forced seals, self-tightening seals that use operating pressure to compress sealing elements are more reliable and compact. The pre-tightening bolts of self-tightening seals only provide the force required for initial sealing. The higher the pressure, the more reliable the seal. Currently, the commonly used high-pressure self-tightening seals are mainly double cone seals and Wood seals. Double cone seals are radial self-tightening seals. This structure requires that the sealing pressure ratio on the two cone surfaces must be greater than the sealing pressure ratio required by the metal gasket. The sealing performance is heavily dependent on the choice of double cone ring material. Although the Wood seal has reliable sealing performance, its structure is complex, the assembly requirements are high, and it takes up a lot of space. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects and provide a high-pressure self-tightening sealing structure and a method of using the same. The high-pressure self-tightening sealing structure includes a flange, a housing, a core shaft, a flexible sealing assembly and a clamping mechanism;

[0004] The upper end of the shell is open and a cavity is provided inside; the core shaft is a stepped shaft structure, including a large diameter section, a middle section and a small diameter section from bottom to top, and the diameter of the middle section is smaller than the diameter of the large diameter section and larger than the diameter of the small diameter section; the shoulder between the large diameter section and the middle section is the first shoulder, and the shoulder between the middle section and the small diameter section is the second shoulder; the core shaft is provided with a gas channel connecting the external gas source and the cavity provided in the shell; the flange is provided with a central through hole, and the lower end face of the flange is provided with a flange. The method of using the present invention includes: sleeve the flexible sealing assembly on the outside of the middle section of the core shaft; make the small diameter section of the core shaft pass through the central through hole of the flange, and make the inner surface of the flange of the flange match with the outer side of the middle section of the core shaft; put the product to be sealed in the cavity provided by the shell; fix the flange to the upper end of the shell, and make the outer surface of the flange, the outer surface of the flexible sealing assembly and the large diameter section of the core shaft match with the inner surface of the cavity provided by the shell from top to bottom; the clamping mechanism presses the flange downward, and then presses the flexible sealing assembly on the first shoulder of the core shaft to achieve initial sealing; the external gas source presses the cavity provided by the shell through the gas channel of the core shaft, lifts the core shaft until the second shoulder of the core shaft contacts the lower end face of the flange, further compresses the flexible sealing assembly, and achieves pressurized sealing. The sealing structure of the present invention can be widely used in the sealing field of high-pressure containers, and has the advantages of simple structure, reliable sealing, novel structure and strong adaptability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A high-pressure self-tightening sealing structure comprises a flange, a shell, a core shaft, a flexible sealing component and a pressing mechanism;

[0007] The upper end of the shell is open, and a cavity is provided inside;

[0008] The core shaft is a stepped shaft structure, including a large diameter section, a middle section and a small diameter section from bottom to top, wherein the diameter of the middle section is smaller than that of the large diameter section and larger than that of the small diameter section; the shaft shoulder between the large diameter section and the middle section is the first shaft shoulder, and the shaft shoulder between the middle section and the small diameter section is the second shaft shoulder; the core shaft is provided with a gas channel connecting an external gas source and a cavity provided in the shell;

[0009] The flange is provided with a central through hole, and the lower end surface of the flange is provided with a flange;

[0010] The flexible sealing component is sleeved on the outer side of the middle section of the core shaft, the small diameter section of the core shaft passes through the central through hole of the flange, and the flange is fixedly installed on the upper end of the shell. The flange outer surface, the outer surface of the flexible sealing component and the large diameter section of the core shaft are matched with the inner surface of the cavity provided in the shell from top to bottom, and the flange inner surface of the flange is matched with the outer side of the middle section of the core shaft. The clamping mechanism presses the flange downward, and since the lower end surface of the flange contacts the flexible sealing component, the flexible sealing component is pressed against the first shaft shoulder of the core shaft through the lower end surface of the flange to achieve initial sealing;

[0011] In the initial sealing state, a gap is provided between the lower end face of the flange and the second shoulder of the core shaft. The external gas source pressurizes the cavity provided in the shell through the gas channel of the core shaft, lifting the core shaft until the second shoulder of the core shaft contacts the lower end face of the flange, further compressing the flexible sealing component to achieve pressurized sealing.

[0012] Furthermore, the flexible sealing assembly of the high-pressure self-tightening sealing structure includes two O-type rubber rings and a metal retaining ring located between the two O-type rubber rings. During initial sealing, the lower end face of the flange presses the upper O-type rubber ring, thereby causing the lower O-type rubber ring to press the first shoulder of the core shaft.

[0013] Furthermore, the clamping mechanism of the above-mentioned high-pressure self-tightening sealing structure is a clamping nut, which is threadedly connected to the small-diameter section of the core shaft, and the lower end of the clamping nut cooperates with the upper end surface of the flange. Tightening the clamping nut realizes downward clamping of the flange.

[0014] Furthermore, the high-pressure self-tightening sealing structure further comprises a hexagonal head bolt, and the flange is fixedly mounted on the upper end of the shell by means of the hexagonal head bolt;

[0015] The upper edge of the inner cavity of the shell is chamfered.

[0016] Furthermore, in the above-mentioned high-pressure self-tightening sealing structure, the inner surface of the flange's flange and the outer side of the middle section of the core shaft are clearance fit, and the outer surface of the flange's flange and the large diameter section of the core shaft and the cavity provided in the shell are clearance fit; the outer diameter of the middle section of the core shaft is equal to the outer diameter of the flange's flange.

[0017] Furthermore, the sum of the heights of the flexible sealing assembly and the flange is greater than the height of the middle section of the core shaft, and the height of the flange is the distance between the lower end of the flange and the lower end surface of the flange inside the flange.

[0018] In the initial sealing state of the high-pressure self-tightening sealing structure, the gap between the lower end surface of the flange and the second shoulder of the core shaft is 0.5 to 0.7 times the inner diameter of the O-type rubber ring.

[0019] Furthermore, the above-mentioned high-pressure self-tightening sealing structure also includes a supporting and fixing component arranged in the shell cavity, and the supporting and fixing component is used to support and fix the product to be sealed, including an upper fixing block and a lower supporting block.

[0020] Furthermore, the upper fixed block and the lower supporting block of the above-mentioned high-pressure self-tightening sealing structure are both made of polytetrafluoroethylene, and grooves are provided on the upper fixed block and the lower supporting block, respectively connecting the upper and lower parts of the upper fixed block and the lower supporting block to provide a passage for the gas in the shell to escape.

[0021] The method for using the above-mentioned high-pressure self-tightening sealing structure comprises the following steps:

[0022] S1. Cover the flexible sealing assembly on the outer side of the middle section of the core shaft;

[0023] S2 makes the small diameter section of the mandrel pass through the central through hole of the flange, and makes the inner surface of the flange fit with the outer side of the middle section of the mandrel;

[0024] S3: placing the product to be sealed in the cavity of the shell;

[0025] S4: The flange is fixedly installed on the upper end of the shell, and the outer surface of the flange, the outer surface of the flexible sealing component and the large diameter section of the core shaft are matched with the inner surface of the cavity provided in the shell from top to bottom;

[0026] The S5 pressing mechanism presses the flange downward, thereby pressing the flexible sealing component onto the first shoulder of the core shaft to achieve initial sealing; at this time, there is a gap between the lower end surface of the flange and the second shoulder of the core shaft;

[0027] S6 The external gas source pressurizes the cavity provided in the shell through the gas channel of the core shaft, lifts the core shaft until the second shaft shoulder of the core shaft contacts the lower end surface of the flange, further compresses the flexible sealing component, and realizes pressurized sealing.

[0028] Furthermore, the method for using the high-pressure self-tightening sealing structure further includes step S7:

[0029] The gas in the cavity of the shell is allowed to reach the external environment through the gas channel of the core shaft, thereby achieving pressure relief of the self-tightening sealing structure.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention utilizes the cooperation of a flexible sealing component, a core shaft, a flange and a shell to obtain a high-pressure self-tightening sealing structure, so that the core shaft actively presses the flexible sealing component after being pressurized to achieve a self-tightening effect. The sealing structure of the present invention can be widely used in the sealing field of high-pressure containers, and has the advantages of simple structure, reliable sealing, novel structure and strong adaptability;

[0032] (2) The present invention designs the flexible sealing assembly as a structure in which a metal retaining ring is sandwiched between two O-shaped rubber rings. After the first seal is established, the second seal is pressed tighter by the first seal, thereby achieving an adaptive compression effect;

[0033] (3) The present invention reasonably designs the compression amount of the flexible sealing component so that only a small part of the internal pressure of the flexible sealing component is maintained, thereby reducing the possibility of the flexible sealing component being damaged due to excessive force and further improving the reliability of the container seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an assembly cross-sectional view of the high-pressure self-tightening sealing structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the assembly structure between the mandrel and the flange, the O-type rubber ring and the metal retaining ring of the present invention;

[0036] Figure 3 It is a structural schematic diagram of the upper fixing block of the present invention;

[0037] Figure 4 It is a structural schematic diagram of the lower support block of the present invention;

[0038] Among them, 1-flange, 2-housing, 3-core shaft, 4-hexagonal head bolt, 5-O-type rubber ring, 6-metal retaining ring, 7-tightening nut, 8-upper fixing block, 9-valve core, 10-lower supporting block, 11-gap. DETAILED DESCRIPTION

[0039] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0040] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0041] The present invention overcomes the problem of unreliable sealing structure performance in the prior art and provides a high-pressure double-layer self-tightening sealing structure with simple structure, reliable sealing, novel structure and strong adaptability.

[0042] like Figure 1 and Figure 2 The high-pressure double-layer self-tightening sealing structure of the present invention comprises a flange 1, a shell 2, a core shaft 3, a flexible sealing component and a clamping mechanism;

[0043] Preferably, the flexible sealing assembly includes two O-type rubber rings 5 ​​and a metal retaining ring 6, and the clamping mechanism is a clamping nut 7; the O-type rubber ring 5, the metal retaining ring 6, and the O-type rubber ring 5 are sequentially installed on the outer side of the middle section of the core shaft 3, and the flange 1 is connected to the core shaft 3 with the clamping nut 7; preferably, the sealing structure also includes an upper fixing block 8 and a lower supporting block 10, and the product to be sealed is a valve core 9. After the lower supporting block 10, the valve core 9, and the upper fixing block 8 are sequentially installed into the housing 2, the flange assembly is then installed on the housing 2. Preferably, the flange assembly and the housing 2 are fixed with hexagonal bolts 4, and the clamping nut 7 is tightened to pre-tighten the O-type rubber ring 5. By pressurizing the housing 3 at the nozzle of the core shaft 3, the core shaft 3 is pressurized, and the two O-type rubber rings 5 ​​are actively and sequentially pressed, so that the O-type rubber rings 5 ​​produce a larger compression amount, forming two O-type rubber ring seals; after the pressurization is completed, the nozzle on the core shaft 3 is opened, and the high pressure in the housing 2 can be quickly discharged to atmospheric pressure. The present invention adds a metal retaining ring structure between two O-type rubber rings, so that the core shaft actively compresses the two O-type rubber rings after being compressed, thereby achieving an adaptive compression effect and realizing high-pressure sealing.

[0044] The principle of the above scheme is: the flange assembly is fixed to the housing 2 by the hexagonal bolt 4. When the compression nut 7 is tightened, the core shaft 3 and the flange 1 will compress the O-type rubber ring 5 and the metal retaining ring 6, so that the two O-type rubber rings 5 ​​in the sealing structure are pre-compressed to form an initial seal. When the pressure in the inner cavity of the housing 2 increases, the pressure will act on the lower end face of the core shaft 3, so that the lower end face of the core shaft 2 and the second axial shoulder formed between the middle section and the small diameter section of the core shaft 3 form a corresponding pressure difference, and continue to compress the O-type rubber ring 5. The first O-type rubber ring 5 will push the metal retaining ring 6 to compress the second O-type rubber ring 5 in the axial direction, so that the compression amount of the second O-type rubber ring 5 increases, thereby increasing the sealing pressure ratio with the metal part, that is, the metal retaining ring 6, forming a two-way O-type rubber ring seal, which can achieve reliable sealing under high pressure conditions.

[0045] Embodiment 1:

[0046] like Figure 1 As shown, the high-pressure double-layer self-tightening sealing structure of the present invention includes a flange 1, a shell 2, a core shaft 3, a hexagonal head bolt 4, an O-ring 5, a metal retaining ring 6, a clamping nut 7, an upper fixing block 8 and a lower supporting block 10. The product to be sealed in this embodiment is a valve core 9.

[0047] The lower end face of the flange 1 is provided with a flange. When the tolerance is not considered, the outer diameter of the flange is equal to the inner diameter of the housing 2. The mandrel 3 is a stepped shaft. When the tolerance is not considered, the diameter of its large diameter section is equal to the inner diameter of the housing 2 and the outer diameter of the flange at the lower end face of the flange 1. The diameter of the middle section of the mandrel 3 is equal to the inner diameter of the flange. When the tolerance is considered, the flange, the mandrel and the housing are all clearance fits. The small diameter section of the mandrel 3 has an external thread of a certain length for matching with the clamping nut 7.

[0048] like Figure 2 During installation, first string two O-type rubber rings 5 ​​and a metal retaining ring 6 on the middle section of the core shaft 3 in the order of O-type rubber ring 5, metal retaining ring 6, and O-type rubber ring 5; then place the flange 1 on the small diameter section of the core shaft 3 from top to bottom, and use the cooperation between the inner surface of the flange and the middle section of the core shaft 3 to position the flange 1 and the core shaft 3; then screw the clamping nut 7 on the small diameter section of the core shaft 3, and the core shaft 3, flange 1, O-type rubber ring 5, and metal retaining ring 6 can be assembled into a flange assembly. At this time, the clamping nut 7 only needs to position the core shaft 3 and the flange 1 to ensure that the two O-type rubber rings 5 ​​are in a natural state, and the second shaft shoulder formed between the middle section and the small diameter section of the core shaft 3 is still at a certain distance from the lower end face of the flange 1 inside the flange after pre-compression, that is, the gap 11, so that the core shaft 3 can move upward under high pressure until it contacts the lower end face of the flange 1. Then put the lower support block 10, valve core 9, and upper fixing block 8 into the housing 2 in order, so that the valve core 9 is fixed between the lower support block 10 and the upper fixing block 8; then insert the lower half of the flange assembly into the housing 2, so that the lower end surface of the flange 1 contacts the upper end surface of the housing 2. The inner cavity edge of the housing 2 is provided with a chamfer to prevent the O-type rubber ring 5 from being scratched when installing the flange assembly. Finally, the flange assembly and the housing 2 are connected together with the hexagonal bolt 4, and the hexagonal bolt 4 is tightened and then the compression nut 7 is tightened to make the O-type rubber ring 5 initially compressed to form the initial sealing condition. At this time, the pre-tightening of the O-type rubber ring 5 is mainly achieved by the hexagonal bolt 4.

[0049] The core shaft 3 is provided with a gas channel connecting the external gas source and the inner cavity of the shell 2. The upper end of the gas channel is set as a nozzle structure. The shell 2 can be pressurized through the nozzle on the core shaft 3. The lower end surface of the core shaft 3 is subjected to pressure, that is, an upward jacking force, so that the core shaft 3 continues to move upward. When the second shoulder formed between the middle section and the small diameter section of the core shaft 3 contacts the lower end surface of the flange 1 inside the flange, the internal pressure is transmitted to the flange 1, and then to the hexagonal head bolt 4. The present invention adopts a sealing structure in which a metal retaining ring 6 is sandwiched between two O-rings 5. When the core shaft 3 is subjected to internal pressure, the two O-rings 5 ​​will be actively compressed. After the first seal is established, the second seal is compressed tighter by the first seal, thereby achieving an adaptive compression effect and realizing high-pressure sealing of the container. In addition, in this structure, the compression amount of the O-ring can be controlled by changing the protruding height of the flange relative to the lower end face of the flange inside the flange. Therefore, only a small part of the internal pressure on the core shaft 3 is borne by the O-ring 5, and most of it is borne by the contact between the second shoulder of the core shaft 3 and the lower end face of the flange 1 inside the flange. This can prevent the O-ring 5 from being damaged by excessive force, and the damaged O-ring 5 is squeezed into the gap between the shell 2 and the flange 1, thereby causing sealing failure.

[0050] like Figure 3 and Figure 4 The upper fixing block 8 and the lower supporting block 10 are both made of polytetrafluoroethylene, and grooves are formed on the upper fixing block 8 and the lower supporting block 10 to facilitate the rapid release of the high pressure in the housing 2 to atmospheric pressure. After the pressurization is completed, the nozzle on the mandrel 3 is opened, and the high pressure in the housing 2 can be quickly released to atmospheric pressure through the gas channel of the mandrel 3 and the grooves on the upper fixing block 8 and the lower supporting block 10.

[0051] The size of the gap 11 between the lower end face of the flange 1 and the second shoulder of the core shaft 3 in the sealing structure of the present invention in the pre-compression state ( Figure 1 The dimension in the vertical direction) is 0.5 to 0.7 times the inner diameter of the O-type rubber ring. After the shell 2 is pressurized, the internal pressure of the shell 2 is ≥100MPa; and when the size of the gap 11 provided between the lower end face of the flange 1 and the second shoulder of the core shaft 3 in the pre-tightened state is less than 0.5 times the inner diameter of the O-type rubber ring, or greater than 0.7 times the inner diameter of the O-type rubber ring, it is difficult to achieve the effect of the present invention, and the internal pressure of the shell 2 is difficult to reach 100MPa.

[0052] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0053] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A high-pressure self-tightening sealing structure, characterized in that: It comprises a flange (1), a housing (2), a core shaft (3), a flexible sealing component and a clamping mechanism; The upper end of the shell (2) is open and a cavity is provided inside; The core shaft (3) is a stepped shaft structure, and comprises, from bottom to top, a large diameter section, a middle section and a small diameter section, wherein the diameter of the middle section is smaller than the diameter of the large diameter section and larger than the diameter of the small diameter section; the shaft shoulder between the large diameter section and the middle section is referred to as the first shaft shoulder, and the shaft shoulder between the middle section and the small diameter section is referred to as the second shaft shoulder; the core shaft (3) is provided with a gas passage connecting an external gas source and a cavity provided in the housing (2); The flange (1) is provided with a central through hole, and the lower end surface of the flange (1) is provided with a flange; The flexible sealing component is sleeved on the outer side of the middle section of the core shaft (3), the small diameter section of the core shaft (3) passes through the central through hole of the flange (1), the flange (1) is fixedly installed on the upper end of the shell (2), the flange outer surface of the flange (1), the outer surface of the flexible sealing component and the large diameter section of the core shaft (3) are matched with the inner surface of the cavity provided in the shell (2) from top to bottom, the flange inner surface of the flange (1) is matched with the outer side of the middle section of the core shaft (3), the clamping mechanism presses the flange (1) downward, and then presses the flexible sealing component onto the first shaft shoulder of the core shaft (3) through the lower end surface of the flange, so as to achieve initial sealing; In the initial sealing state, a gap is provided between the lower end surface of the flange (1) and the second shoulder of the core shaft (3), and an external gas source is pressurized into the cavity provided in the shell (2) through the gas passage of the core shaft (3), thereby lifting the core shaft (3) until the second shoulder of the core shaft (3) contacts the lower end surface of the flange (1), further compressing the flexible sealing component to achieve pressurized sealing.

2. A high pressure self-tightening sealing structure according to claim 1, characterized in that: The flexible sealing assembly comprises two O-type rubber rings (5) and a metal retaining ring (6) located between the two O-type rubber rings (5).

3. A high pressure self-tightening sealing structure according to claim 1, characterized in that: The clamping mechanism is a clamping nut (7), which is threadedly connected to the small-diameter section of the core shaft (3), and the lower end of the clamping nut (7) cooperates with the upper end surface of the flange (1). The flange (1) is clamped downward by tightening the clamping nut (7).

4. A high pressure self-tightening sealing structure according to claim 1, characterized in that: It also includes a hexagonal head bolt (4), and the flange (1) is fixedly mounted on the upper end of the housing (2) by means of the hexagonal head bolt (4); The upper edge of the inner cavity of the shell (2) is provided with a chamfer.

5. A high pressure self-tightening sealing structure according to claim 1, characterized in that: The inner surface of the flange (1) and the outer side of the middle section of the core shaft (3) are in clearance fit, and the outer surface of the flange (1) and the large diameter section of the core shaft (3) and the cavity provided in the shell (2) are in clearance fit; the outer diameter of the middle section of the core shaft (3) is equal to the outer diameter of the flange of the flange (1).

6. A high pressure self-tightening sealing structure according to claim 2, characterized in that: In the initial sealing state, the gap between the lower end surface of the flange (1) and the second shaft shoulder of the core shaft (3) is 0.5 to 0.7 times the inner diameter of the O-type rubber ring (5).

7. A high pressure self-tightening sealing structure according to claim 1, characterized in that: It also includes a supporting and fixing assembly arranged in the cavity of the shell (2), and the supporting and fixing assembly is used to support and fix the product to be sealed, and includes an upper fixing block (8) and a lower supporting block (10).

8. A high pressure self-tightening sealing structure according to claim 7, characterized in that: The upper fixing block (8) and the lower supporting block (10) are both made of polytetrafluoroethylene. The upper fixing block (8) and the lower supporting block (10) are both provided with grooves. The grooves are respectively connected to the upper and lower parts of the upper fixing block (8) and the lower supporting block (10) to provide a passage for the gas in the housing (2) to escape.

9. A method for using a high-pressure self-tightening sealing structure according to any one of claims 1 to 8, characterized in that: The steps include: S1: sleeve the flexible sealing assembly onto the outer side of the middle section of the core shaft (3); S2: making the small diameter section of the core shaft (3) pass through the central through hole of the flange (1), and making the inner surface of the flange (1) fit with the outer side of the middle section of the core shaft (3); S3 placing the product to be sealed into the cavity provided in the housing (2); S4: fixing the flange (1) to the upper end of the housing (2), and making the outer surface of the flange (1), the outer surface of the flexible sealing component and the large diameter section of the core shaft (3) match with the inner surface of the cavity provided in the housing (2) from top to bottom; The S5 pressing mechanism presses down the flange (1), thereby pressing the flexible sealing component onto the first shoulder of the core shaft (3) to achieve initial sealing; The S6 external gas source pressurizes the cavity provided in the shell (2) through the gas channel of the core shaft (3), lifts the core shaft (3) until the second shaft shoulder of the core shaft (3) contacts the lower end surface of the flange (1), further compresses the flexible sealing component, and realizes pressurized sealing.

10. The method for using a high-pressure self-tightening sealing structure according to claim 9, characterized in that: The step S7 is also included: The gas in the cavity provided in the shell (2) reaches the external environment through the gas passage of the core shaft (3), thereby achieving pressure relief of the self-tightening sealing structure.

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