Three-section type composite material air cylinder

Abstract

The invention relates to a three-section type composite material air cylinder which comprises two oppositely-arranged shells, and each shell is provided with an opening end; the connecting piece is arranged between the opening ends of the two shells; wherein the opening end of the shell or the end face of the connecting piece is provided with a groove extending in the circumferential direction, and the shell and the connecting piece are bonded through the groove. The shell and the connecting piece are in surface contact connection through the double-layer bonding surface of the groove, under the condition of the same pressure intensity, the surface contact structure has a larger stress area, stress concentration can be effectively reduced, stress distribution of the connecting part is more uniform, the groove has a limiting effect, the connecting precision is ensured, and the service life of the shell is prolonged. And the air tightness of the connecting part and the reliability of the whole structure are improved.

Description

Technical Field

[0001] The present application relates to the technical field of automobile parts, and in particular to a three-section composite material air storage cylinder. Background Art

[0002] Air reservoirs are widely used in automotive, rail transit, and construction machinery applications, primarily for storing and transporting compressed air or other gases. In existing technology, air reservoirs typically employ a segmented structure, consisting of two or more sections connected by welding or bolting. While this design facilitates manufacturing and assembly, it presents numerous drawbacks in practical applications, impacting the structural strength and airtightness of the air reservoir.

[0003] In welded structures, stress concentration areas are easily formed at the joints. Especially under high-pressure conditions or dynamic loads (such as vibration and impact), fatigue cracks are prone to appear in the welds. In severe cases, they may cause the cylinder to burst, posing a major safety hazard.

[0004] While bolt-on construction avoids the problems associated with welding, it does require a connecting boss at the end of the cylinder, which is then fastened with bolts. This increases the overall volume of the cylinder, taking up too much installation space and hindering lightweight design requirements. Summary of the Invention

[0005] The embodiment of the present application provides a three-section composite gas storage cylinder to solve the problem of insufficient structural strength and air tightness of the connection parts of multi-section gas storage cylinders in the related art.

[0006] In a first aspect, a three-section composite material gas storage cylinder is provided, comprising: Two oppositely disposed housings, each housing having an open end; A connecting member is provided between the open ends of the two shells; Wherein, the opening end of the shell or the end surface of the connecting piece is provided with a groove extending along the circumferential direction, and the shell and the connecting piece are bonded via the groove.

[0007] In some embodiments, the groove is arranged on both side end surfaces of the connecting member, and the groove includes an inner groove wall and an outer groove wall, the inner groove wall is bonded to the inner wall surface of the opening end of the shell, and the outer groove wall is bonded to the outer wall surface of the opening end of the shell.

[0008] In some embodiments, the groove is arranged on the end surface of the open end of the shell, and the groove includes an inner groove wall and an outer groove wall. The inner wall surface of the connecting member is bonded to the inner groove wall of the groove, and the outer wall surface of the connecting member is bonded to the outer groove wall of the groove.

[0009] In some embodiments, a radially extending partition is provided at the center of the connecting member; The partition adopts an axially protruding arc-shaped structure.

[0010] In some embodiments, a plurality of guide and limiting ribs are provided circumferentially on the inner wall of the groove, and the guide and limiting ribs are arranged along the axial direction.

[0011] In some embodiments, the housing and the connector are bonded together using structural adhesive.

[0012] In some embodiments, the structural adhesive is made of a two-component acrylic material.

[0013] In some embodiments, the depth of the groove is calculated based on the radius of the gas reservoir, the design pressure, the shear strength of the structural adhesive, and a correction factor; The correction coefficient is the ratio of the actual bonding strength of the structural adhesive to the theoretically calculated bonding strength.

[0014] In some embodiments, the housing is provided with a connector, and the connector is connected to the housing through an insert pre-embedding process; A mounting bracket is provided on the outside of the shell, and the mounting bracket is connected to the shell through a bonding process or a friction welding process.

[0015] In some embodiments, the connecting member is arranged perpendicularly or parallel to the axis of the housing.

[0016] The embodiment of the present application provides a three-section composite material gas storage cylinder, in which connectors are provided at the open ends of the two shells, and grooves are provided on the end faces of the connectors, and the open ends of the shells extend into the grooves, or grooves are provided at the open ends of the shells, and the connectors extend into the grooves of the shells, forming a double-layer bonding surface. Compared with the line contact connection method of the traditional welding process, the present application realizes surface contact connection through the double-layer bonding surface of the grooves. Under the same pressure conditions, the surface contact structure has a larger force-bearing area, which can effectively reduce stress concentration and make the stress distribution of the connection part more uniform. Compared with the single-sided overlap, the double-sided surface contact further improves the compressive performance, and the groove has a limiting effect, which ensures the connection accuracy and improves the airtightness of the connection part and the reliability of the overall structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A schematic diagram of the structure of a three-section composite material gas storage cylinder provided in an embodiment of the present application; Figure 2Schematic diagram of the cross-sectional structure of the three-section composite material gas storage cylinder provided in the embodiment of this application Figure I ; Figure 3 Schematic diagram of the cross-sectional structure of the three-section composite material gas storage cylinder provided in the embodiment of this application Figure II ; Figure 4 for Figure 3 A in the middle is an enlarged structural diagram; Figure 5 Stress cloud diagram of compressive strength analysis at 1.2MPa; Figure 6 Stress cloud for 4 MPa compressive strength analysis.

[0019] In the figure: 1. Shell; 101. Open end; 2. Connector; 201. Partition; 3. Groove; 301. Inner groove wall; 302. Outer groove wall; 4. Connector; 5. Mounting bracket. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0021] The embodiment of the present application provides a three-section composite material gas storage cylinder, which can solve the problem of insufficient structural strength and air tightness of the connection parts of the multi-section gas storage cylinder in the related art.

[0022] Example 1: like Figures 1 to 4 As shown, a three-section composite gas storage cylinder comprises: Two oppositely disposed shells 1, each of which is cylindrical and has an open end 101; The connecting member 2 is cylindrical in shape, open at both ends, and is disposed between the open ends 101 of the two shells 1; The opening end 101 of the housing 1 or the end surface of the connecting member 2 is provided with a groove 3 extending in the circumferential direction, and the housing 1 and the connecting member 2 are bonded via the groove 3 .

[0023] The present application realizes a three-section modular design through two shells 1 and a connector 2. Connectors 2 are arranged at the open ends 101 of the two shells 1, and grooves 3 are respectively arranged on the end faces of the connector 2 on both sides. The open end 101 of the shell 1 extends into the groove 3, or a groove 3 is arranged at the open end 101 of the shell 1, and the connector 2 extends into the groove 3 of the shell 1. The double-layer bonding surface of the groove 3 enables a surface contact connection between the shell 1 and the connector 2. Compared with the line contact connection method of the traditional welding process, under the same pressure conditions, the surface contact structure has a larger force area, which can effectively reduce stress concentration and make the stress distribution of the connection part more uniform. Compared with the single-sided overlap, the double-sided surface contact further improves the pressure resistance, and the groove 3 has a limiting function, which ensures the connection accuracy and improves the airtightness of the connection part and the overall structural reliability.

[0024] Furthermore, the groove 3 is provided on both side end faces of the connector 2, and the groove 3 includes an inner groove wall 301 and an outer groove wall 302. The inner groove wall 301 is bonded to the inner wall surface of the shell opening end, and the outer groove wall 302 is bonded to the outer wall surface of the shell opening end. Each shell 1 and connector 2 adopts a 30mm wide overlap structure, that is, the depth of the groove 3 is 30mm; the double-sided structural design of the groove 3 can effectively increase the bonding area while reducing the axial size of the connector 2, thereby improving the structural strength of the connector 2. During the design process, if the connector 2 and the shell 1 adopt a single-sided overlap method, to achieve the same contact area, the axial depth of the groove 3 needs to be increased to 60mm; while using the double-sided overlap structure of this solution, only a groove depth of 30mm is required to achieve the same bonding area.

[0025] Furthermore, a radially extending partition 201 is provided at the center of the connector 2. In the three-section composite gas storage cylinder structure of the present application, the shells 1 at both ends are designed as universal parts, and their structural specifications remain consistent, which can adapt to different types of intermediate connectors; and the connector 2 located in the middle is divided into two types, with a partition 201 and without a partition 201, and the two types of connectors 2 match the open end of the shell 1. This modular design allows the gas storage cylinder to conveniently switch between single-chamber and dual-chamber functions by simply replacing the intermediate connector 2: when a connector 2 without a partition 201 is used, the two shells 1 are connected through the connector 2 to form a single-chamber structure gas storage cylinder; when replaced with a connector 2 with a partition 201, the partition 201 completely separates the internal space of the two shells 1 to form an independent dual-chamber structure, and the two cavities can respectively store gases of different pressures or different media. It effectively solves the technical problem that composite pressure vessels prepared by the existing continuous winding process cannot achieve a dual-cavity structure due to their overall molding characteristics. While ensuring the lightweight and high-strength advantages of composite gas cylinders, it significantly improves the functional flexibility and applicable scenarios of the product, and reduces the development cost and cycle for different cavity requirements.

[0026] Furthermore, the partition 201 adopts an axially protruding arc-shaped structure, which has a more uniform force distribution and can withstand greater pressure compared to a planar structure.

[0027] Furthermore, the housings 1 at both ends are designed as universal parts with a rotationally symmetrical design, and the position of the adapter interface can be adjusted by angle.

[0028] Furthermore, housing 1 is provided with a connector 4 for connecting the internal and external pipes of the gas reservoir. In this embodiment, connector 4 is a threaded metal connector that is pre-embedded using an insert process. During the injection molding of the end parts, it is directly injection-molded and connected, which effectively improves the connection strength and airtightness.

[0029] Furthermore, a mounting bracket 5 is provided on the exterior of the housing 1 for mounting the gas cylinder on the vehicle. Directly attached to the housing 1 via adhesive or friction welding, the mounting bracket 5 can be flexibly adjusted. Compared to a strap connection, this design is simpler and significantly reduces costs.

[0030] Furthermore, the connecting member 2 is arranged perpendicular to the axis of the shell 1, and is installed in a manner of connecting along the radial direction of the cylindrical structure formed by the two shells 1.

[0031] In some optional embodiments, the connecting member 2 is arranged parallel to the axis of the shell 1, that is, the connection is performed along the axial direction of the two shells 1 forming a cylindrical shape.

[0032] Furthermore, the inner wall of the groove 3 is provided with a plurality of guide limit ribs in the circumferential direction, and the guide limit ribs are arranged in the axial direction, that is, the inner groove wall 301 and the outer groove wall 302 are provided with a plurality of guide limit ribs. When the open end of the shell 1 is inserted into the groove 3 of the connector 2, the plurality of guide limit ribs can play a guiding role in the insertion process of the shell 1: by forming a fitting limit with the inner wall surface or the outer wall surface of the open end of the shell 1, the radial displacement of the shell 1 can be effectively limited, ensuring that the preset coaxiality between the shell 1 and the groove 3 is maintained, and avoiding the unevenness of the fitting clearance between the two due to assembly eccentricity. The guide limit ribs can control the distance between the shell 1 and the inner wall of the groove 3, thereby ensuring that the thickness of the adhesive layer in each circumferential area is uniform; at the same time, with the help of the radial support effect of the guide limit ribs, the problem of excessive or insufficient local gaps due to eccentricity of the shell 1 during the insertion process can be prevented, thereby avoiding the situation where insufficient or even lack of adhesive is caused by abnormal gaps in some areas, and ensuring that the sealing and connection strength of the bonding surface are not affected by assembly deviation.

[0033] Furthermore, the housing 1 and connector 2 are bonded together using structural adhesive. Specifically, structural adhesive is evenly applied to the mating surfaces between the open end of the housing 1 and the inner and outer groove walls 301 and 302 of the groove 3 of the connector 2. The adhesive cures, forming a secure, integrated connection. Compared to traditional mechanical connections or welding, this bonding method avoids stress concentration points at the joint, better adapts to the mechanical properties of composite materials, and ensures the overall structural integrity of the gas reservoir.

[0034] Furthermore, the structural adhesive uses a two-component acrylic material. On the one hand, the two-component acrylic structural adhesive cures quickly after mixing, significantly shortening the assembly cycle and improving production efficiency. On the other hand, the adhesive layer formed after curing has excellent mechanical properties, including high shear strength and tensile strength, which can effectively resist the radial and axial forces caused by the internal air pressure of the gas reservoir, ensuring the stability of the connection. At the same time, the material also has excellent media resistance and aging resistance. During contact with the stored medium in the gas reservoir and long-term use, it is not prone to chemical corrosion or performance degradation, and can maintain reliable bonding and sealing performance over the long term, further improving the service life and safety factor of the three-section composite gas reservoir.

[0035] Furthermore, the depth of the groove 3 is calculated based on the radius of the gas reservoir, the design pressure, the shear strength of the structural adhesive, and the correction factor. If the depth of the groove 3 is too deep, the overall weight of the gas reservoir will increase, while if the depth is too shallow, the bonding surface area will be insufficient, affecting the compressive strength.

[0036]

[0037]

[0038] During the test, the radius of the gas cylinder R Set to 125mm, the nominal shear strength of the structural adhesive T According to the design requirements, the bonding strength of the structural adhesive is 18MPa. F2 The pressure at the opening end of the shell 1 must be at least F1 2 times (safety factor n= 2).

[0039] The calculation formula for the shell opening end pressure F1 is: F1=A1*P= ; The calculation formula of structural adhesive bonding strength F2 is: F2=A2*T=

[0040] Where, A1 is the pressure area at the opening end of the shell 1; A2 is the bonding area of ​​the structural adhesive; R is the radius of the gas reservoir; P Design pressure for the gas reservoir; h is the groove depth; T is the shear strength of structural adhesive.

[0041] In the initial design, the design pressure and cylinder size are fixed values. P To provide sufficient bonding strength, the bonding width is 30 mm. Substitute the specific parameters for calculation: F2= ≈3.14*2*125*30*18=423900N; F1= ≈3.14*125*125*4.0=196250N; at this time, F2≥F1*n , theoretically a 30mm wide bonding joint can meet the design requirements.

[0042] However, when the sample pressure test was conducted, the actual results showed a significant deviation from the theoretical calculation: when the actual pressure rose to 1.4 MPa, the adhesive joint failed. F1*n= 68688*2=137376N, this value is much lower than the theoretical calculation F2 (423900N), indicating that there is a significant gap between the actual bonding force and the theoretical value. In order to correct this deviation, the bonding joint correction factor is introduced. K , that is, it must meet the following requirements: F2*K≥F1*n; Calculated from test data K=F1*n / F2= 137376 / 423900=0.32; To further verify the stability of the correction factor, the bonding width was increased to 60mm and the test was continued. After multiple tests, the actual pressure failed at 2.6MPa. K The values ​​are: K=F1*n / F2≈ 127563*2 / 847800=0.30; Two trials K The values ​​(0.32 and 0.30) are close, indicating that in this type of bonded structure, the correction factor has a certain stability and can be taken as 0.3~0.32 for practical design.

[0043] An in-depth analysis of the reasons for the deviation shows that the actual bonding joint strength is lower than the theoretical value mainly due to many factors: first, the strength of the structural adhesive itself may be affected by the ambient temperature and humidity, curing time, etc. during the actual curing process, and the nominal shear strength may not be fully achieved; second, there may be pollutants such as oil and oxide layer on the surface of the part, or the surface roughness may be insufficient, resulting in a decrease in the adhesion strength between the structural adhesive and the part surface; in addition, process problems such as uniformity of adhesive application and residual bubbles during the bonding process will also weaken the actual bonding effect.

[0044] Based on the above conclusions, in the subsequent strength design of bonded joints, the bonding coefficient needs to be increased for correction; F2*K≥F1*n, K is the correction coefficient for bonded joints, and its value ranges from 0.3 to 0.32.

[0045] At the same time, the correction factor can be improved by optimizing the process: for example, plasma treatment is used to remove surface pollutants of parts and introduce polar functional groups, or laser polishing is used to increase surface roughness. These measures can effectively improve the adhesion between the surface of parts and structural adhesives, thereby improving K Values ​​can be increased, reducing the required bonding width and optimizing structural design. Structural adhesive bonding replaces friction welding, resolving the problem of insufficient weld strength (bonding strength reaches 25% → 100% of the parent material). Surface treatment technology can also be used to increase the adhesion of the bonding area.

[0046] Finally, after the above derivation, the groove depth is calculated as: h≥RPn / 2TK , ( n =2, K =0.3~0.32).

[0047] Based on CAE simulation analysis, this technology specifically designs the gas reservoir structure and materials to verify its pressure resistance under actual operating conditions. Based on technical specifications and regulatory requirements for gas reservoir use, two typical operating conditions—air tightness testing (1.2 MPa pressure) and static pressure testing (4.0 MPa pressure)—were selected for pressure strength simulation analysis, covering key pressure scenarios encountered in the product's actual service life.

[0048] From the simulation results, under the 4.0MPa static pressure test condition, the maximum stress of the gas cylinder reaches 162MPa, which is concentrated in the end transition fillet and segment connection edge area - these parts are prone to stress concentration effects due to sudden changes in geometric shapes, such as fillet transition and segment splicing. Through the optimized compressive strength analysis stress cloud diagram, such as the simulation model Figure 5 and Figure 6As shown, the stress distribution under different pressure conditions shows a gradient change, and the maximum stress point is identifiable and traceable, which can intuitively verify the rationality of the structural design: while meeting the 4.0MPa pressure resistance requirement, the stress concentration area does not exceed the allowable strength range of the material, proving that the structure and material scheme adopted by this technology can stably support the gas storage cylinder to withstand the design pressure, providing a digital verification basis for product reliability.

[0049] CAE simulation and actual testing form a "digital-physical" closed loop: simulation verifies pressure resistance from the macro-structural level, and testing verifies bonding reliability from the micro-joint level. The two work together to ensure the service capability of the gas cylinder under complex working conditions, laying a solid foundation for technical verification for the entire product process from design to mass production.

[0050] According to the technical requirements and regulatory requirements for the use of gas cylinders, two working conditions were selected: the gas cylinder air tightness test requirement pressure of 1.2MPa and the static pressure test strength requirement pressure of 4.0MPa for pressure resistance simulation analysis. The maximum stress is 162MPa, which occurs at the end transition fillet and the segment connection edge area. Figure 5 and Figure 6 Stress cloud diagram for optimized compressive strength analysis.

[0051] In this embodiment, both the housing 1 and the connector 2 are made of a discontinuous glass fiber composite material, PA6GF50. Field measurements have shown this material to exhibit excellent performance: a density of only 1578 kg / m³, a tensile strength ≥202 MPa, a flexural modulus of 15.6 GPa, and an elongation at break of 1.7%. Its high strength and high modulus properties allow it to meet the strength and stiffness requirements of the gas reservoir's maximum pressure resistance of 4 MPa with a minimum wall thickness of only 4 mm, achieving a balance between lightweighting and mechanical performance.

[0052] In terms of lightweighting and cost control, compared to the industry's mainstream steel air reservoirs, the weight is reduced by 70% due to the advantages of material density and structural design. Furthermore, the simplicity of the injection molding process and the material cost advantages can reduce costs by 10%. Compared to the industry's conventional aluminum alloy lightweight air reservoirs, this 10% weight reduction achieves a cost reduction of over 45%.

[0053] In terms of manufacturing process, the shell 1 and the connector 2 use non-continuous glass fiber injection molding technology. A closed pressure vessel segmented design is adopted, and the single shell 1 is an open structure. It can be molded with the help of conventional injection molding technology, breaking away from the dependence of continuous glass fiber composite winding technology on complex professional equipment and harsh process environment. Compared with the continuous glass fiber winding solution, the equipment investment for part molding is less, the process flow is simpler and more efficient, the cost can be reduced by 20%, and the production of thin-walled and high-glass fiber content parts can be stably achieved. Subsequently, by molding the three parts separately and then assembling them, it not only simplifies the manufacturing difficulty of individual parts, but also facilitates quality control and replacement of defective products in the production process, promoting cost reduction, efficiency improvement and process innovation from design to manufacturing.

[0054]

[0055] Example 2: A three-section composite material air storage cylinder, comprising: Two housings 1 arranged opposite to each other, each housing 1 having an open end 101; The connecting member 2 is provided between the open ends 101 of the two housings 1; The opening end 101 of the housing 1 or the end surface of the connecting member 2 is provided with a groove 3 extending in the circumferential direction, and the housing 1 and the connecting member 2 are bonded via the groove 3 .

[0056] Furthermore, a radially extending partition 201 is provided at the center of the connecting member 2 .

[0057] Furthermore, a plurality of guide and limiting ribs are provided on the inner wall of the groove 3 in the circumferential direction, and the guide and limiting ribs are provided along the axial direction, that is, a plurality of guide and limiting ribs are provided on both the inner groove wall 301 and the outer groove wall 302 .

[0058] Furthermore, the housing 1 and the connector 2 are bonded together by means of structural adhesive.

[0059] Furthermore, the structural adhesive adopts a two-component acrylic material.

[0060] Furthermore, the depth of the groove 3 is calculated based on the radius of the gas reservoir, the design pressure, the shear strength of the structural adhesive and the correction factor.

[0061] Furthermore, the correction factor is the ratio of the actual bonding strength of the structural adhesive to the theoretically calculated bonding strength.

[0062] The difference between Example 2 and Example 1 is that the groove 3 is arranged on the end face of the open end of the shell 1, the groove 3 includes an inner groove wall 301 and an outer groove wall 302, the inner wall surface of the connecting part 2 is bonded to the inner groove wall 301 of the groove, and the outer wall surface of the connecting part 2 is bonded to the outer groove wall 302 of the groove 3.

[0063] As an extension of Example 1, the only difference is in processing. The two remain consistent in core functions - through the double bonding of the inner and outer groove walls and the corresponding fitting surfaces, both can provide the air storage cylinder with sufficient pressure resistance and sealing effect. The structural adhesive transmits force evenly under the constraint of the groove wall, effectively resisting the separation force generated by the internal pressure.

[0064] Example 3: A three-section composite material air storage cylinder, comprising: Two oppositely disposed shells 1, each of which is cylindrical and has an open end 101; The connecting member 2 is cylindrical in shape, open at both ends, and is disposed between the open ends 101 of the two shells 1; The opening end 101 of the housing 1 or the end surface of the connecting member 2 is provided with a groove 3 extending in the circumferential direction, and the housing 1 and the connecting member 2 are bonded via the groove 3 .

[0065] Furthermore, a radially extending partition 201 is provided at the center of the connecting member 2 .

[0066] Furthermore, a plurality of guide and limiting ribs are provided on the inner wall of the groove 3 in the circumferential direction, and the guide and limiting ribs are provided along the axial direction, that is, a plurality of guide and limiting ribs are provided on both the inner groove wall 301 and the outer groove wall 302 .

[0067] Furthermore, the housing 1 and the connector 2 are bonded together by means of structural adhesive.

[0068] Furthermore, the structural adhesive adopts a two-component acrylic material.

[0069] Furthermore, the depth of the groove 3 is calculated based on the radius of the gas reservoir, the design pressure, the shear strength of the structural adhesive and the correction factor.

[0070] Furthermore, the correction factor is the ratio of the actual bonding strength of the structural adhesive to the theoretically calculated bonding strength.

[0071] Example 3 differs from Examples 1 and 2 in that groove 3 is threaded, and the housing or connector 2 is provided with matching threads. While retaining the bonding capabilities of Examples 1 and 2, a mechanical interlocking mechanism is added, creating a dual-security system of "threaded connection + structural adhesive bonding." In practice, a trapezoidal thread profile is recommended, as it ensures sufficient thread strength while not interfering with adhesive filling. The spiral sealing line of the threaded pair and the filling seal of the structural adhesive work synergistically to form a composite axial and radial sealing structure.

[0072] Specifically, when groove 3 is provided on both side surfaces of connector 2, groove 3 includes inner groove wall 301 and outer groove wall 302. Inner groove wall 301 is bonded to the inner wall surface of the open end of housing 1, and outer groove wall 302 is bonded to the outer wall surface of the open end of housing. At least one groove wall of groove 3 is threaded, and housing 1 and connector 2 are threadedly connected.

[0073] When the inner groove wall 301 of the groove 3 is threaded, the inner wall surface of the housing 1 is pre-machined with matching internal threads. During assembly, structural adhesive is first evenly applied to the groove 3 of the connector 2, and then to the open end of the housing 1. The housing 1 is then screwed into the groove 3 of the connector 2 along the threads. During the tightening process, the mechanical engagement of the threads provides an initial axial preload, ensuring a tight fit between the housing 1 and the groove wall of the connector 2. Simultaneously, the structural adhesive is squeezed to fill the gaps between the threads and the gap between the groove wall and the housing, preventing air bubbles from remaining.

[0074] This "thread + bonding" composite connection method achieves a synergistic enhancement of mechanical properties: the threaded connection directly transmits radial and axial forces through tooth engagement, effectively resisting the separation trend caused by the internal pressure of the air cylinder, and the structural adhesive forms an elastic adhesive layer after curing, which not only fills the gap caused by thread processing errors, but also absorbs vibration energy through shear deformation, reducing stress concentration on the thread teeth. In terms of sealing performance, the spiral line seal of the thread and the filling seal of the structural adhesive form a double barrier.

[0075] From a process compatibility perspective, the groove and threads of connector 2 can be machined simultaneously on a CNC lathe, ensuring the coaxiality of the inner and outer groove threads. The inner threads of housing 1 and the outer wall of the opening can also be machined simultaneously, ensuring precise fit with the connector. Once the structural adhesive cures, the adhesive layer and threaded assembly form an inseparable whole, preventing thread loosening while leveraging the adhesive's elasticity to compensate for thermal stress caused by temperature fluctuations.

[0076] In addition, this design also has assembly flexibility: if only the inner groove wall 301 is provided with threads, the outer groove wall 302 can retain a smooth surface, and matching threads are provided on the inner wall surface of the shell 1; if only the outer groove wall 302 is provided with threads, the inner groove wall 301 can retain a smooth surface, and matching threads are provided on the outer wall surface of the shell 1; if both the inner and outer groove walls are provided with threads, matching threads need to be provided on the inner and outer walls of the shell 1, which can further improve the mechanical locking capability and adapt to higher pressure working conditions.

[0077] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0078] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0079] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A three-section composite material gas storage cylinder, characterized in that: It includes: Two housings (1) arranged opposite to each other, each housing (1) having an open end (101); A connecting member (2) is provided between the open ends (101) of the two shells (1); The opening end (101) of the shell (1) or the end surface of the connecting member (2) is provided with a groove (3) extending in the circumferential direction, and the shell (1) and the connecting member (2) are bonded via the groove (3).

2. The three-section composite material gas reservoir according to claim 1, characterized in that: The groove (3) is provided on both side end surfaces of the connecting member (2), and the groove (3) comprises an inner groove wall (301) and an outer groove wall (302), wherein the inner groove wall (301) is bonded to the inner wall surface of the shell opening end, and the outer groove wall (302) is bonded to the outer wall surface of the shell opening end.

3. The three-section composite material gas reservoir according to claim 1, characterized in that: The groove (3) is provided on the end surface of the open end of the housing (1), and the groove (3) comprises an inner groove wall (301) and an outer groove wall (302). The inner wall surface of the connecting member (2) is bonded to the inner groove wall (301) of the groove, and the outer wall surface of the connecting member (2) is bonded to the outer groove wall (302) of the groove (3).

4. The three-section composite material gas reservoir according to claim 1, characterized in that: A radially extending partition (201) is provided at the center of the connecting member (2); The partition (201) adopts an axially protruding arc-shaped structure.

5. The three-section composite material gas reservoir according to claim 1, characterized in that: A plurality of guide and limiting ribs are provided circumferentially on the inner wall of the groove (3), and the guide and limiting ribs are arranged along the axial direction.

6. The three-section composite gas reservoir according to claim 1, characterized in that: The housing (1) and the connecting piece (2) are bonded together using structural adhesive.

7. The three-section composite material gas reservoir according to claim 6, characterized in that: The structural adhesive is made of two-component acrylic material.

8. The three-section composite material gas reservoir according to claim 6, characterized in that: The depth of the groove (3) is calculated based on the radius of the gas cylinder, the design pressure, the shear strength of the structural adhesive and the correction factor; The correction coefficient is the ratio of the actual bonding strength of the structural adhesive to the theoretically calculated bonding strength.

9. The three-section composite material gas reservoir according to claim 1, characterized in that: The housing (1) is provided with a joint (4), and the joint (4) is connected to the housing (1) through an insert pre-embedding process; A mounting bracket (5) is provided on the outside of the housing (1), and the mounting bracket (5) is connected to the housing (1) through a bonding process or a friction welding process.

10. The three-section composite material gas reservoir according to claim 1, characterized in that: The connecting member (2) is arranged perpendicularly or parallel to the axis of the housing (1).

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