High-voltage-resistant bidirectional combined O-shaped sealing ring and vulcanization forming method

Abstract

The application discloses a high-voltage bidirectional combined O-shaped sealing ring and a vulcanization forming method, and belongs to the technical field of sealing. The high-voltage bidirectional combined O-shaped sealing ring comprises a central pressure guide cavity which is arranged in the central region of the main sealing ring body and forms a closed ring cavity in a continuous ring shape; bidirectional pressure guide channels are arranged on the two sides of the central pressure guide cavity and are arranged in a mirror image, one end of the bidirectional pressure guide channel is communicated with an external medium contact area, and the other end is communicated with the central pressure guide cavity; a self-expanding support wing is arranged at the end of each bidirectional pressure guide channel and is located in the main sealing ring body, and the self-expanding support wing can generate radial expansion deformation when being pressed. The application realizes bidirectional automatic response sealing without distinguishing the installation direction, avoids the response lag of the traditional check ring structure, ensures that the contact stress of the main sealing arc surface is synchronously enhanced with the increase of pressure, constructs a pressure self-enhancing sealing system, and breaks through the pressure upper limit of the traditional O-shaped ring which relies on the initial interference amount.

Description

Technical Field

[0001] This invention relates to the field of sealing technology, and in particular to a high-pressure-resistant bidirectional combined O-ring and a vulcanization molding method. Background Technology

[0002] In hydraulic systems, deep-sea equipment, high-pressure valve groups, hydrogen storage and transportation equipment, and high-pressure rotary joints, seals are often subjected to working pressures of 20MPa to 120MPa, temperatures of -60℃ to 220℃, and pressure pulsation frequencies of 0.5Hz to 200Hz. Traditional O-rings often employ a single elastomer structure. When subjected to high pressure, their contact stress migrates towards the low-pressure side edge as the pressure increases, resulting in localized stress concentration. Under alternating bidirectional pressure conditions, this stress concentration area is repeatedly subjected to compression, causing the material to be gradually squeezed into the sealing gap, resulting in extrusion deformation, accompanied by permanent compressive deformation and stress fatigue cracks, ultimately leading to seal failure, equipment downtime, and high maintenance costs.

[0003] To address the aforementioned issues, existing technologies often employ a combination structure of "O-ring + retaining ring". However, this type of structure still has significant drawbacks in practical applications: while the retaining ring on the high-pressure side can suppress extrusion, it causes further concentration of contact stress on the high-pressure side, while the low-pressure side lacks effective support, resulting in insufficient contact pressure; when the pressure direction reverses, the retaining ring cannot synchronously switch its support area with the pressure direction, leading to a delayed response and an instantaneous leakage channel at the sealing interface; furthermore, the retaining ring and O-ring work independently, making it difficult to simultaneously ensure high-pressure anti-extrusion performance while also meeting the requirements of low friction and dynamic following.

[0004] The aforementioned defects make it difficult for traditional sealing structures to operate reliably for a long time in bidirectional high-pressure alternating environments. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-pressure-resistant bidirectional combined O-ring and a vulcanization molding method. It aims to solve the problems of uneven contact stress distribution, easy extrusion deformation, lag in pressure reversal response, and inability to balance high pressure support and low friction in the prior art under bidirectional high pressure alternating working conditions.

[0006] To achieve the aforementioned objectives, the first aspect of this invention provides a high-pressure-resistant bidirectional composite O-ring seal and a vulcanization molding method, comprising a main sealing ring body with a closed-loop annular structure, and further comprising: The central pressure guiding cavity is located in the central region inside the main sealing ring body and is continuously connected along the circumference to form a closed annular cavity; A bidirectional pressure channel is respectively disposed on both sides of the central pressure channel and arranged in a mirror image. One end of the bidirectional pressure channel is connected to the contact area of ​​the external medium, and the other end is connected to the central pressure channel. The self-expanding support wing is disposed at the end of each of the bidirectional pressure channels and located inside the main sealing ring body. The self-expanding support wing can generate radial expansion deformation when under pressure. A gradient limiting skeleton, embedded inside the main sealing ring and in a continuous ring structure, is used to limit the maximum deformation of the self-expanding support wing.

[0007] Optionally, the tilt angle α of the bidirectional pressure channel satisfies: 20°≤α≤55°, so as to form a pressure guiding path and generate a directional pressure amplification effect.

[0008] Optionally, the diameter of the central pressure guiding cavity is 0.18 to 0.35 times the cross-sectional diameter of the main sealing ring.

[0009] Optionally, the cross-section of the self-expanding support wing has an involute arc-shaped structure, and its thickness is 0.08 to 0.22 times the diameter D of the main sealing ring cross-section.

[0010] Optionally, the cross-section of the gradient limiting skeleton is corrugated, the height of the crest is 0.03 to 0.12 times the diameter D of the main sealing ring cross-section, and its material is one of PEEK, PEKK or carbon fiber reinforced PEEK.

[0011] Optionally, the cross-section of the main sealing ring body has a modified hyperbolic profile, and its outer periphery forms a first sealing arc surface and a second sealing arc surface arranged symmetrically about the central axis.

[0012] Optionally, it also includes a reverse extrusion energy blocking layer disposed on both sides of the sealing ring. The reverse extrusion energy blocking layer is made of a high-modulus nanocomposite elastomer, the modulus of which is 2 to 6 times that of the main sealing ring body material.

[0013] Optionally, the material of the main sealing ring is a blend of hydrogenated nitrile rubber and fluororubber, with a Shore A hardness range of 75 to 88.

[0014] A second aspect of this invention provides a vulcanization molding method for a high-pressure-resistant bidirectional composite O-ring as described above, comprising the following steps: S1, Prepare the main sealing layer adhesive material by using a blend system of hydrogenated nitrile rubber and fluororubber, and premix it with nano-silica and graphene sheets; S2, prepare a high-modulus barrier layer compound, the modulus of which is controlled to be 2 to 6 times the modulus of the main sealing layer compound; S3 adopts a multi-layer coaxial pre-forming process to form a three-layer composite structure consisting of a main sealing layer, a blocking layer, and a skeleton pre-embedded layer. S4, the gradient limiting skeleton is placed into a special mold, and concentric positioning is achieved through the positioning groove; S5, after mold closing, adopts zoned pressure vulcanization, successively going through the low-pressure pre-flow stage, the high-pressure shaping stage and the pressure-holding cross-linking stage, in order to form a central pressure guiding cavity and a self-expanding support wing structure. S6 undergoes post-vulcanization treatment at a temperature range of 180℃ to 230℃ for a time range of 2h to 12h to obtain a stable cross-linked network.

[0015] Optionally, the method also includes step S7: performing pressure pre-activation training by using cyclic pressure loading to enable the self-expanding support wing to form a stable response memory, thereby improving the initial unsealing performance.

[0016] The beneficial effects of this invention are: 1. The high-pressure-resistant bidirectional combined O-ring seal and vulcanization molding method of the present invention constitute an internal pressure guiding network by setting a central pressure guiding cavity and mirror-symmetrical bidirectional pressure guiding channels inside the main sealing ring body. When the medium pressure acts from either side, the pressure enters the central pressure guiding cavity through the pressure guiding channel on that side and drives the self-expanding support wing on the same side to expand radially, while the support wing on the opposite side does not move; when the pressure direction is reversed, the two sides automatically switch, thereby realizing bidirectional automatic response sealing without distinguishing the installation direction, avoiding the response lag of the traditional retaining ring structure.

[0017] 2. The high-pressure-resistant bidirectional combined O-ring and vulcanization molding method of the present invention adopts an external medium pressure that is introduced through a pressure guiding channel and directly acts on the self-expanding support wing. Its involute arc cross-section structure converts the pressure into a radial expansion force, and this expansion force is positively correlated with the medium pressure. The embedded gradient limiting skeleton constrains the maximum deformation of the expansion wing through its corrugated cross-section, ensuring that the contact stress of the main sealing arc surface increases synchronously with the increase of pressure, thus constructing a pressure self-reinforcing sealing system, breaking through the pressure resistance limit of traditional O-rings that rely on the initial interference.

[0018] 3. The high-pressure-resistant bidirectional combined O-ring seal and vulcanization molding method of the present invention, during the expansion of the self-expanding support wing, promotes local volume redistribution of the main sealing ring body, optimizing the contact stress distribution; simultaneously, the anti-extrusion energy blocking layer set on both sides of the sealing ring utilizes its high modulus of 2 to 6 times that of the main material to form a stiffness gradient, which can effectively block the extrusion flow of the matrix material into the sealing gap under high pressure, significantly reducing the extrusion risk and improving the adaptability of the limit gap. The self-expanding support wing and the gradient limiting skeleton jointly participate in the load-bearing, reducing the local stress amplitude borne by the elastomer matrix of the main sealing ring body, thereby reducing permanent compression deformation and extending the service life of the seal.

[0019] 4. The high-pressure-resistant bidirectional combined O-ring and vulcanization molding method of the present invention integrates sealing function, radial support function and deformation limiting function into one unit through the sealing ring. The gradient limiting skeleton and the reverse extrusion energy blocking layer work together to reduce or even eliminate the configuration of independent retaining rings and simplify the structure of the sealing system. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the high-pressure-resistant bidirectional combined O-ring seal according to an embodiment of the present invention; Figure 2 for Figure 1 A magnified view of a portion of point A in the middle; Figure 3 This is a process flow diagram of the vulcanization molding method of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Main sealing ring body; 11. First sealing arc surface; 12. Second sealing arc surface; 2. Central pressure guiding cavity; 4. Self-expanding support wing; 5. Gradient limiting skeleton; 51. Corrugated limiting section; 6. Reverse extrusion energy blocking layer; 7. Equipment installation trench; 8. High pressure medium inlet.

[0022] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Example 1 Reference Figures 1-3 This embodiment provides a high-pressure-resistant bidirectional combined O-ring seal, which has an overall closed-loop annular elastomer structure. For example... Figures 1 to 3 As shown, it includes a main sealing ring 1, a central pressure guiding cavity 2, a bidirectional pressure guiding channel, a self-expanding support wing 4, a gradient limiting skeleton 5, and a reverse extrusion energy blocking layer 6.

[0026] The main sealing ring 1 is a closed-loop ring with a modified hyperbolic profile in its cross-section. Its outer periphery forms a first sealing arc surface 11 and a second sealing arc surface 12, symmetrically arranged about the central axis, which are used to form a sealing contact with the sidewall and bottom of the equipment installation trench 7, respectively. The main material of the main sealing ring 1 is a blend of hydrogenated nitrile rubber and fluororubber, with a Shore A hardness controlled within the range of 75–88 to balance media resistance, low compression set, and elastic recovery.

[0027] The central pressure-guiding cavity 2 is located in the central region of the cross-section of the main sealing ring 1, and extends continuously along the circumference to form a closed annular cavity. The diameter of the central pressure-guiding cavity 2 is 0.18 to 0.35 times the diameter D of the cross-section of the main sealing ring 1. The central pressure-guiding cavity 2 is used to receive the medium pressure from the bidirectional pressure-guiding channels and uniformly transmit it to the structures on both sides.

[0028] Bidirectional pressure guiding channels are respectively arranged on both sides of the central pressure guiding cavity 2 in a mirror-symmetrical manner. One end of each bidirectional pressure guiding channel opens onto the outer surface of the main sealing ring 1 and communicates with the external medium contact area, serving as the high-pressure medium inlet 8; the other end communicates with the central pressure guiding cavity 2. The axis of the bidirectional pressure guiding channel is inclined relative to the radial direction of the main sealing ring 1, with an inclination angle α satisfying 20°≤α≤55°. This inclined design forms a pressure guiding path, allowing the external medium pressure to enter the cavity in a directional manner and producing a local pressure amplification effect.

[0029] The self-expanding support wing 4 is located at the end region of each bidirectional pressure channel and inside the main sealing ring 1. Figure 2 As shown, the self-expanding support wing 4 has an involute arc-shaped cross-section, and its thickness is 0.08 to 0.22 times the diameter D of the main sealing ring 1. The root of the self-expanding support wing 4 near the central pressure guiding cavity 2 is connected to the base of the main sealing ring 1. When the medium pressure acts on the inner surface of the self-expanding support wing 4 through the bidirectional pressure guiding channel and the central pressure guiding cavity 2, its arc-shaped structure can convert the pressure into radially outward expansion deformation, forming a continuous support ring along the circumference.

[0030] The gradient limiting skeleton 5 is embedded inside the main sealing ring 1, located in the outermost radial region of the self-expanding support wing 4, and continuously arranged along the circumference to form a ring-shaped constraint structure. The cross-section of the gradient limiting skeleton 5 is corrugated, with alternating peaks and troughs, wherein the peak height is 0.03 to 0.12 times the diameter D of the main sealing ring 1. Figure 2As shown, the crest section constitutes the corrugated limiting section 51. When the self-expanding support wing 4 expands to a predetermined extent, the corrugated limiting section 51 contacts the outer surface of the self-expanding support wing 4, thereby limiting its further expansion and achieving gradient control of the deformation. The material of the gradient limiting skeleton 5 is selected from PEEK, PEKK, or carbon fiber reinforced PEEK. This type of material has high rigidity, high strength, and excellent chemical resistance.

[0031] The reverse extrusion energy blocking layer 6 is disposed on both sides of the sealing ring, that is, on both sides adjacent to the gap with the equipment mounting groove 7. The reverse extrusion energy blocking layer 6 is made of a high-modulus nanocomposite elastomer, whose elastic modulus is 2 to 6 times that of the main material of the main sealing ring 1, thereby forming a stiffness gradient from the matrix to the edge. This blocking layer can effectively prevent the extrusion flow of the matrix material into the gap under the drive of high-pressure medium.

[0032] In this embodiment, the sealing ring constructs a bidirectional pressure self-conversion stress circulation sealing mechanism during operation, and its working principle is as follows: When an external high-pressure medium acts from one side, the high-pressure medium on that side enters the bidirectional pressure channel on the corresponding side through the high-pressure medium inlet 8 and flows into the central pressure channel 2. The pressure energy is transmitted through the central pressure channel 2 to the inner surface of the self-expanding support wing 4 on that side, driving the self-expanding support wing 4 to expand radially outward. During the expansion process, the self-expanding support wing 4 flips over, pushing the first sealing arc surface 11 and the second sealing arc surface 12 of the main sealing ring body 1 to press against the side wall and bottom of the equipment mounting groove 7, respectively, forming the first sealing contact area. At this time, the corrugated limiting section 51 of the gradient limiting skeleton 5 mechanically limits the expansion stroke of the self-expanding support wing 4 to prevent it from being over-deformed.

[0033] The force transmission and closed-loop stress circulation path is as follows: medium pressure → bidirectional pressure channel → central pressure channel 2 → self-expanding support wing 4 → gradient limiting frame 5 → first sealing arc surface 11 and second sealing arc surface 12 → equipment mounting groove 7 → reverse extrusion energy blocking layer 6 → finally transmitted back to the groove constraint boundary, forming a closed-loop force system. Traditional O-rings concentrate stress at the contact edge, while this invention disperses pressure throughout the entire circulation structure through the above path, significantly reducing local peak stress.

[0034] When the pressure direction of the medium reverses, the self-expanding support wing 4 is activated, and the self-expanding support wing 4, which was originally on the high-pressure side, is released. The entire process is completed automatically without any external control. Thus, under bidirectional alternating pressure, the sealing contact stress always adaptively reconfigures with the direction of the medium pressure, achieving a self-reinforcing effect where the higher the pressure, the stronger the support.

[0035] In a preferred embodiment, when the medium pressure reaches a first threshold, the self-expanding support wing 4 begins to exhibit perceptible radial expansion; when the pressure continues to rise to a second threshold, the self-expanding support wing 4 enters a secondary support state, at which point the contact area rapidly increases, and the contact stress growth rate exceeds the medium pressure growth rate, further enhancing the ultra-high pressure sealing capability. Even in the event of instantaneous overpressure, the gradient limiting skeleton 5 will first contact the groove wall of the equipment mounting trench 7, forming a rigid mechanical limit, while the reverse extrusion energy blocking layer 6 maintains the barrier function, preventing catastrophic sealing failure.

[0036] Example 2 This embodiment also provides a vulcanization molding method for the high-pressure-resistant bidirectional combined O-ring, referring to... Figure 3 This includes the following steps: Step S1: Preparation of the main sealing layer compound. A blend of hydrogenated nitrile rubber and fluororubber is used as the matrix. Nano-silica and graphene sheets are added during the mixing process for premixing to obtain a uniformly dispersed reinforcing compound.

[0037] Step S2: Prepare the high-modulus barrier layer compound. By adjusting the filler ratio and crosslinking system, its elastic modulus is controlled to be 2 to 6 times that of the main sealing layer compound.

[0038] Step S3: Employ a multi-layer coaxial preforming process. The main sealing layer adhesive, the blocking layer adhesive, and the adhesive layer for the pre-embedded gradient limiting skeleton 5 are coaxially extruded or laminated in the design sequence to form a three-layer composite preform containing the main sealing layer, the blocking layer, and the pre-embedded skeleton layer.

[0039] Step S4: Place the gradient limiting skeleton 5 into a special mold. The mold has a positioning groove that matches the shape of the gradient limiting skeleton 5. The positioning groove is used to achieve concentric positioning of the gradient limiting skeleton 5 and ensure its coaxiality with the rubber layer.

[0040] Step S5: After mold closing, zoned pressure vulcanization is employed. The vulcanization process proceeds sequentially as follows: a low-pressure pre-flow stage, allowing the rubber compound to fully fill the mold cavity and form the initial shape of the central pressure-guiding cavity 2 and the self-expanding support wing 4; a high-pressure setting stage, ensuring the interfaces of each layer are densely fused, precisely forming the involute arc-shaped support wing and channel structure; and a pressure-holding cross-linking stage, allowing the rubber to fully cross-link and set. Typical vulcanization pressure parameters are: 5MPa~10MPa for the low-pressure pre-flow stage, 15MPa~25MPa for the high-pressure setting stage, and mold temperature controlled at 160℃~180℃.

[0041] Step S6: Perform post-vulcanization treatment. Place the demolded sealing ring in an oven and maintain a constant temperature of 180℃~230℃ for 2h~12h to further improve the cross-linking network and obtain stable physical and mechanical properties.

[0042] Step S7: Perform pressure pre-activation training. Install the vulcanized sealing ring in the simulated groove and apply cyclic pressure, with the pressure amplitude between 0 and 80% of the rated working pressure, for 10 to 50 cycles. Through cyclic loading, the self-expanding support wing 4 forms a stable deformation response memory, improving the initial unsealing performance.

[0043] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-pressure-resistant bidirectional composite O-ring seal, comprising a main sealing ring body (1) with a closed-loop annular structure, characterized in that, Also includes: The central pressure guiding cavity (2) is located in the central region inside the main sealing ring (1) and is continuously connected along the circumference to form a closed annular cavity; A bidirectional pressure channel is respectively set on both sides of the central pressure channel (2) and arranged in a mirror image. One end of the bidirectional pressure channel is connected to the contact area of ​​the external medium, and the other end is connected to the central pressure channel (2). The self-expanding support wing (4) is disposed at the end of each of the bidirectional pressure channels and located inside the main sealing ring body (1). The self-expanding support wing (4) can generate radial expansion deformation when under pressure. The gradient limiting skeleton (5) is embedded inside the main sealing ring (1) and has a continuous ring structure, which is used to limit the maximum deformation of the self-expanding support wing (4).

2. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The inclination angle α of the bidirectional pressure channel satisfies: 20°≤α≤55°, so as to form a pressure guiding path and generate a directional pressure amplification effect.

3. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The diameter of the central pressure guiding cavity (2) is 0.18 to 0.35 times the cross-sectional diameter of the main sealing ring (1).

4. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The cross-section of the self-expanding support wing (4) is an involute arc structure, and its thickness is 0.08 to 0.22 times the diameter D of the cross-section of the main sealing ring (1).

5. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The gradient limiting skeleton (5) has a corrugated cross section, with the peak height being 0.03 to 0.12 times the diameter D of the main sealing ring (1) cross section, and its material is one of PEEK, PEKK or carbon fiber reinforced PEEK.

6. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The main sealing ring (1) has a modified hyperbolic profile in cross section, and its outer periphery forms a first sealing arc surface (11) and a second sealing arc surface (12) arranged symmetrically about the central axis.

7. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, It also includes a reverse extrusion energy blocking layer (6), which is disposed on both sides of the sealing ring. The reverse extrusion energy blocking layer (6) is made of a high-modulus nanocomposite elastomer, and its modulus is 2 to 6 times that of the main sealing ring body (1) material.

8. The high-pressure-resistant bidirectional combined O-ring according to claim 1, characterized in that, The main sealing ring (1) is made of a blend of hydrogenated nitrile rubber and fluororubber, with a Shore A hardness range of 75 to 88.

9. A vulcanization molding method for a high-pressure-resistant bidirectional composite O-ring as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1, Prepare the main sealing layer adhesive material by using a blend system of hydrogenated nitrile rubber and fluororubber, and premix it with nano-silica and graphene sheets; S2, prepare a high-modulus barrier layer compound, the modulus of which is controlled to be 2 to 6 times the modulus of the main sealing layer compound; S3 adopts a multi-layer coaxial pre-forming process to form a three-layer composite structure consisting of a main sealing layer, a blocking layer, and a skeleton pre-embedded layer. S4, the gradient limiting skeleton (5) is placed into the special mold and concentric positioning is achieved through the positioning groove; S5, after the mold is closed, the partition pressure vulcanization is adopted, and the low pressure pre-flow stage, high pressure shaping stage and pressure holding crosslinking stage are successively used to form the central pressure guiding cavity (2) and the self-expanding support wing (4) structure. S6 undergoes post-vulcanization treatment at a temperature range of 180℃ to 230℃ for a time range of 2h to 12h to obtain a stable cross-linked network.

10. The vulcanization molding method for the high-pressure-resistant bidirectional combined O-ring according to claim 9, characterized in that, It also includes step S7: performing pressure pre-activation training by using cyclic pressure loading to make the self-expanding support wing (4) form a stable response memory to improve the initial opening performance.

Images