A tapering structure for an electric ignition tube

Abstract

This utility model discloses a constriction structure for an electric ignition tube, including a shell, an electrode plug, a propellant ring, a plug, a cover plate, and a propellant charge. The output end of the shell has an annular step, and the plug is nested within this step and fixedly connected by a radial constriction. The plug has a central through hole with a diameter smaller than the outer diameter of the propellant ring, used to limit the propellant ring during ignition and prevent it from flying out. The lower end of the plug has a secondary step, and the cover plate is bonded to this step with high-temperature resistant adhesive and coated with a moisture-proof paint. The cover plate is made of a moderately thick, easily breakable material with a weak adhesive structure, preferentially breaking when the combustion pressure reaches a threshold to achieve pressure relief. The contact area between the plug and the shell has a rounded corner structure to optimize stress distribution, and the constriction gap is filled with a high-temperature resistant sealant layer to enhance overall sealing. This utility model has the beneficial effects of reliable propellant ring constriction, a safe pressure relief mechanism, reasonable stress distribution, and excellent sealing performance.

Description

Technical Field

[0001] This utility model relates to the field of pyrotechnics technology, and in particular to a constriction structure for an electric ignition tube. Background Technology

[0002] As a core component in the field of pyrotechnics, the electric ignition tube is widely used in aerospace systems. Its function is to rapidly ignite the main propellant charge of the system using the high-temperature flame or pressure generated by gunpowder combustion, ensuring a rapid system response. Traditional electric ignition tubes typically use a cap to directly seal the end, which has the following drawbacks: 1. Risk of propellant ring scattering: After the ignition tube is ignited, the impact force generated by the combustion of the internal propellant can easily cause the propellant ring to loosen. Due to the lack of an effective restraint mechanism, the loose propellant ring may fly out from the output end at high speed, causing damage to subsequent mechanisms or blocking the ignition channel, ultimately leading to system failure. 2. Cover plate shear failure: When the cover plate is directly fixed to the outer shell, the internal pressure rises sharply at the moment of ignition. The cover plate is subjected to huge shear force and is easily sheared off along the edge of the closed end, forming high-speed fragments that threaten subsequent mechanisms or the charge. 3. Conflict between sealing performance and structural strength: To ensure sealing performance, the closing pressure needs to be increased, but excessive closing can easily lead to deformation and cracking of the cover plate, resulting in poor sealing performance and reduced reliability; 4. Right-angle stress concentration at the closing point can cause cracks at the closing point, which reduces the strength of the closing point or worsens its sealing performance.

[0003] Patent CN218509590U, Figure 5, discloses a structure in which the cover is directly closed at the end of the shell, but there are risks of cover shearing, excessive closure leading to cover deformation and breakage, and stress concentration at right angles at the closure point causing closure cracks; Patent CN2813151Y proposes a multi-lobed spring clamp closure device, which improves clamping uniformity, but does not solve the problems of charge ring scattering and sealing.

[0004] The aforementioned technical defects indicate that the traditional electric ignition tube retraction structure has significant bottlenecks in terms of safety, reliability, and environmental adaptability, and there is an urgent need for an innovative design that takes into account dynamic constraints, staged pressure relief, and high sealing performance. Utility Model Content

[0005] The purpose of this invention is to solve problems such as propellant ring scattering, cap shear failure, and insufficient sealing. It provides an electric ignition tube termination structure that combines high constraint, staged pressure relief, and multiple sealing functions. This is achieved through a composite structure design that utilizes dynamic limiting of the plug-cap through-hole, two-stage stepped adhesive sealing, rounded corner stress optimization, and epoxy resin filling. This structure combines optimized mechanical constraints with multiple sealing guarantees, significantly improving the safety and reliability of pyrotechnic devices.

[0006] This utility model is achieved using the following technical solution: a closing structure for an electric ignition tube, characterized in that it includes a shell, an electrode plug, a charge ring, a plug, a cover plate, and a charge. The output end of the shell is provided with an annular step, and the plug is nested within the annular step and fixedly connected by a radial closing method. The plug is provided with a central through hole, the diameter of which is smaller than the outer diameter of the charge ring, so as to physically limit the charge ring during combustion. The lower end face of the plug is provided with a secondary step, the upper surface of which is used to bond and fix the cover plate. The cover plate is made of a fragile material and is bonded to the upper surface of the step with a high-temperature resistant adhesive. After the adhesive layer cures, a moisture-proof paint is applied to the outer surface of the cover plate. This weak fixing structure allows the cover plate to break and release pressure preferentially when the combustion pressure reaches a threshold. The contact part between the plug and the closing part of the shell is provided with a rounded corner to optimize stress distribution. The closing gap between the shell and the plug is filled with a high-temperature resistant sealing adhesive layer to enhance sealing performance.

[0007] Furthermore, the height of the annular step is the sum of the height of the cap and the wall thickness of the cap. This structural dimensional fit ensures that the cap forms a tight fit with the outer shell after radial contraction, effectively dispersing the contraction stress while ensuring structural compactness and stability.

[0008] Furthermore, the cover plate has a thickness of 0.05~0.3mm, and the material is selected from aluminum foil or tin foil. The selected material and thickness range can ensure the necessary sealing while enabling rapid rupture and pressure relief, preventing the formation of high-speed flying fragments, and improving safety in use.

[0009] Furthermore, the moisture-proof paint is an alcohol-based shellac varnish, applied to the surface of the cover plate at a concentration of 15% to 35%. This moisture-proof coating effectively blocks moisture penetration, keeps the propellant dry, and improves the reliability of the product in high-humidity environments.

[0010] Furthermore, the diameter D1 of the plug hole and the outer diameter D2 of the charging ring satisfy the following condition: 0.6D2≤D1≤0.8D2. This dimensional matching achieves physical limitation while ensuring unobstructed ignition channels, effectively controlling combustion gas pressure, and avoiding excessive impact on the structure.

[0011] Furthermore, the fillet radius R is 0.2~0.5mm, and the wall thickness t of the cap's closing section satisfies t≥2R. This structural design significantly reduces the risk of local stress concentration, prevents cracks due to material fatigue, and improves the fatigue strength and sealing stability of the closing area.

[0012] Furthermore, the depth of the secondary step is 2 to 4 times the thickness of the cover plate. This matching relationship between the step depth and the cover plate thickness ensures a firm bond to the cover plate and effectively controls the tearing path of the cover plate during pressure relief, preventing detached fragments from damaging the system.

[0013] The beneficial effects of the closing structure of the electric ignition tube described in this utility model include: 1. Dynamic mechanical interference limiting: The diameter D1 of the plug hole is smaller than the outer diameter D2 of the charge ring, and the charge ring is limited from flying out by mechanical interference.

[0014] 2. Staged pressure relief: The cover is bonded to the secondary step with a high-temperature resistant adhesive layer, ensuring that the cover can break and release internal pressure preferentially under a very small threshold (not exceeding 1MPa), avoiding high-speed ejection; and by controlling the matching size of the plug hole with the inner hole of the outer shell, the gas pressure is prevented from impacting the closing position and the plug, so that the closing position and the plug maintain structural integrity to constrain the charge ring.

[0015] 3. Triple composite seal: The plug and the annular step are precisely fitted together to form a first seal. The epoxy resin layer fills the micro gaps at the joint to form a second seal. The lower end face of the plug is provided with a second step for attaching the cover plate, and the surface of the cover plate is coated with moisture-proof paint to form a triple seal.

[0016] 4. Stress optimization: The edges of the plug are rounded to eliminate stress concentration at right angles.

[0017] 5. Nested design of plug and step: The output end of the outer shell is provided with an annular step, and the plug is nested and fixed by the closing, which is different from the structure of the traditional direct closing cover.

[0018] This utility model, through a four-in-one design of "dynamic limiting, graded pressure relief, composite sealing and stress optimization", breaks through the technical bottlenecks of traditional electric ignition tube retraction structures in terms of safety, reliability and environmental adaptability, and is especially suitable for key fields such as aerospace systems where safety and reliability requirements are extremely high. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a front sectional view of the electric ignition tube of this utility model; Figure 2 This is a front sectional view of the outer casing of this utility model; Figure 3 This is a front sectional view of the plug of this utility model; Figure 4 This is a front sectional view of the charge ring of this utility model; In the figure, 1-outer shell; 101-annular step; 102-retracting edge; 2-electrode plug; 3-charge ring; 4-cover plate; 5-plug cap; 6-charge; 501-through hole; 502-secondary step; 503-rounded corner. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0023] like Figure 1-4 As shown, this embodiment provides a closing structure for an electric ignition tube, including a housing 1, an electrode plug 2, a propellant ring 3, a cover 4, a plug 5, and a propellant 6; the output end of the housing 1 is provided with an annular step 101, the plug 5 is nested in the annular step 101, and is fixedly connected by a radial closing method.

[0024] Specifically, the wall thickness T of the annular step 101 is 0.3 mm, and its height H1 is the sum of the height H2 of the plug 5 and its wall thickness t, i.e., H1=H2+t, to ensure that the plug 5 is in full contact with the outer shell 1 after the end is closed and formed, and to avoid affecting the normal conduction of the fire transmission channel due to the end edge 102 covering the through hole 501 of the plug 5.

[0025] The plug 5 has a through hole 501 in the center, the diameter of which is smaller than the outer diameter of the charge ring 3, D2. After ignition, it can form an effective physical limit to prevent the charge ring 3 from flying out due to impact. The lower end face of the plug 5 is provided with a secondary step 502, the diameter of which is smaller than the inner diameter of the outer shell 1, D4. The cover plate (4) is bonded and fixed to the upper surface of the secondary step 502.

[0026] The cover plate 4 is an aluminum foil with a thickness of 0.1 mm and a surface coated with 15-35% alcohol shellac varnish, which has good sealing performance and moisture resistance. The cover plate 4 achieves weak fixation through the adhesive layer. When the pressure generated by the combustion of the charge 6 exceeds the set threshold, it can break and release pressure first, so as to avoid the plug 5 from bearing too large impact load.

[0027] In addition, the edges of the plug 5 and the outer shell 1 are rounded with a radius of R=0.5mm, which can effectively eliminate stress concentration problems; the wall thickness of the closing part is t=1mm, which meets the structural safety requirement of t=2R; the gap between the plug 5 and the outer shell 1 is filled with epoxy resin to improve the sealing effect.

[0028] Through the above design, the sealing structure in this embodiment did not show any cracks in mechanical tests and environmental adaptation tests, and the charging ring did not fly out after ignition, demonstrating high safety and reliability. Example

[0029] This embodiment is a further optimization based on Embodiment 1, specifically: The improved matching degree between the stepped wall thickness of the outer shell 1 and the material of the cover plate 4 enhances the overall structure's load-bearing capacity under high pressure.

[0030] Specifically, the wall thickness T of the annular step 101 provided at the output end of the outer shell 1 is 0.8mm, and its height still satisfies the structural dimension relationship H1=H2+t; the plug 5 is nested in the step 101, fixed by radial closing, and forms full contact to effectively disperse the impact stress generated by ignition.

[0031] The through hole 501 set in the center of the plug 5 has a diameter D1 that is 0.8 times the outer diameter D2 of the charging ring 3. This not only maintains a good limiting function, but also avoids excessive gas pressure generated during the combustion of the ignition tube, which would cause excessive impact on the closing position and thus damage.

[0032] The depth of the secondary step 502 at the lower end of the plug 5 is twice the thickness of the cover plate 4, and it is used to bond the cover plate 4. The cover plate 4 is made of 0.2mm thick tin foil material, coated with alcohol shellac paint, which has high sealing performance. The bonding method is a weak fixing structure, which allows automatic rupture and pressure relief when the internal pressure reaches the threshold (≤1MPa), without forming high-speed flying pieces.

[0033] The contact edge between the plug 5 and the outer shell 1 is also provided with a rounded corner 503, with a radius R=0.2mm and a wall thickness t=0.6mm at the closing part, which meets the design requirement of t>2R; the gap between the plug 5 and the outer shell 1 is filled with a high-temperature resistant epoxy resin adhesive layer to further improve the sealing performance.

[0034] The above structure has been verified to be in a high-intensity vibration and high temperature and humidity environment without loosening or sealing failure, without cracks appearing in the sealing area, with the cover plate breaking completely after ignition, unobstructed pressure relief, and stable position of the charging ring, thus meeting the high reliability requirements.

[0035] The above embodiments describe the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Modifications and variations made by those skilled in the art without departing from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. An electric ignition tube closure structure, characterized by comprising: The device includes a housing (1), an electrode plug (2), a charge ring (3), a plug (5), a cover plate (4), and a charge (6). The output end of the housing (1) is provided with an annular step (101). The plug (5) is nested in the annular step (101) and fixedly connected by a radial closing method. The plug (5) is provided with a central through hole (501). The diameter of the through hole (501) is smaller than the outer diameter of the charge ring (3) so as to physically limit the charge ring (3) when the charge is burning. The lower end face of the plug (5) is provided with a secondary platform. Step (502), the upper surface of which is used to bond and fix the cover plate (4); the cover plate (4) is made of a fragile material and is bonded to the upper surface of the step with a high temperature resistant adhesive, and a moisture-proof paint is applied to the outer surface of the cover plate (4) after the adhesive layer is cured; so that the cover plate (4) will break and release pressure preferentially when the combustion pressure reaches the threshold; the contact part between the plug (5) and the outer shell (1) is provided with a rounded corner (503) to optimize the stress distribution; the gap between the outer shell (1) and the plug (5) is filled with a high temperature resistant sealant layer to enhance the sealing performance.

2. The pinch structure of an electric ignition tube according to claim 1, wherein The height of the annular step (101) is the sum of the height of the plug (5) and the wall thickness of the plug (5).

3. The pinch structure of an electric ignition tube according to claim 1, wherein The cover plate (4) has a thickness of 0.05~0.3mm and is made of aluminum foil or tin foil.

4. The pinch structure of an electric ignition tube according to claim 1, wherein The moisture-proof paint is an alcohol-based shellac paint, which is applied to the surface of the cover plate (4) at a concentration of 15% to 35%.

5. The closing structure of an electric ignition tube according to claim 1, characterized in that, The diameter D1 of the through hole (501) of the plug (5) and the outer diameter D2 of the charging ring (3) satisfy: 0.6D2≤D1≤0.8D2.

6. The closing structure of an electric ignition tube according to claim 1, characterized in that, The radius R of the fillet (503) is 0.2~0.5mm, and the wall thickness t of the closing part of the plug (5) satisfies t≥2R.

7. The closing structure of an electric ignition tube according to claim 1, characterized in that, The depth of the secondary step (502) is 2 to 4 times the thickness of the cover plate (4).

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