A rocket igniter and a method of forming the same

Abstract

The application discloses a rocket ignition device, comprising a cover assembly and a combustion chamber assembly, the cover assembly is arranged at the cavity opening of the combustion chamber assembly; the cover assembly is composed of an outer shell, a heat insulation lining and an ignition charge containing structure, the combustion chamber assembly comprises a force bearing shell layer, an auxiliary heat insulation layer, a heat insulation protection layer and a reinforcing connection structure; the application also provides a forming method of the rocket ignition device, which comprises the following steps: step one, preparing a burn-resistant EPDM material; step two, pressing a closed end, comprising the following preheating, charging and pressing processes; step three, preparing the force bearing shell layer, comprising the preheating, forming and curing processes; step four, die forming, comprising the preheating, mould loading and pressing processes; step five, machining and bonding of the combustion chamber assembly; step six, size inspection; step seven, water pressure test; and step eight, hole milling. The problems of internal block dropping and burning of the combustion chamber assembly are solved, and the structure damage caused by the fire jumping of the bonding interface is avoided.

Description

Technical Field

[0001] This invention relates to the field of engine ignition device technology, specifically to a rocket-type ignition device and its molding method. Background Technology

[0002] Solid rocket engines are widely used in rockets, missiles, and boosters. The ignition device is the starting component of a solid rocket engine, and its function is to accurately and reliably ignite the main propellant grain, allowing the engine to enter normal operation as predetermined. It is extremely important and prone to failure. Among them, the propellant-containing structure ignition device and the basket ignition device are the most commonly used. However, if a basket ignition device is used in larger engines, it will generate excessive vibration and impact during ignition, and may even cause deflagration, damaging the engine. Therefore, a rocket-type ignition device is used, which can safely and effectively ignite larger engines. Compared with other ignition devices, its ignition gas flow and combustion time can be strictly controlled, and the propellant grain burns according to a predetermined pattern, without local high pressure or deflagration.

[0003] A rocket-type ignition device is essentially a small solid rocket motor, characterized by high operating pressure, large gas flow rate, and short combustion time. However, existing rocket-type ignition devices use fiberglass winding for the combustion chamber assembly shell, with a high-silica fiberglass bushing molded and bonded to the tail section. Because the shell is fiber-wound, side leakage can occur when the ignition pressure exceeds 10 MPa, leading to shell vibration, localized high pressure, and the risk of deflagration. Furthermore, the high-silica fiberglass bushing is only bonded to the tail section, increasing the risk of chipping, burn-through, and other ablation of the internal surfaces of the combustion chamber assembly shell during operation. The bonded tail section can also ignite under high temperature and pressure, causing it to detach. Therefore, a novel rocket-type ignition device and its molding method are urgent problems that need to be solved by those skilled in the art. Summary of the Invention

[0004] This invention provides a rocket-type ignition device, comprising: a cover assembly and a combustion chamber assembly, wherein the cover assembly and the combustion chamber assembly are sealed together.

[0005] The cover assembly consists of an outer shell, a heat insulation liner, and an ignition charge receiving structure, wherein the ignition charge receiving structure is embedded in one end of the outer shell through the heat insulation liner.

[0006] The combustion chamber assembly is configured as a multi-layer composite shell structure, which includes a load-bearing shell layer. The outer surface of the load-bearing shell layer is provided with a reinforcing connection structure. The inner wall of the load-bearing shell layer has a heat insulation protective layer. An auxiliary heat insulation layer is also provided on the outer side of the load-bearing shell layer near the outer shell.

[0007] The combustion chamber assembly is fitted with a closed end cap, which is configured as a curved transition structure to reduce airflow disturbance during ignition.

[0008] The closed end is provided with at least three axisymmetrically distributed spray holes.

[0009] Optionally, the auxiliary heat insulation layer, the heat insulation protection layer, and the heat insulation lining are all made of ablation-resistant EPDM rubber material.

[0010] Optionally, the load-bearing shell layer is formed by winding glass fiber, and the cross-sectional thickness of the load-bearing shell layer at the closed end increases as the diameter of the closed end decreases.

[0011] A method for molding a rocket-type ignition device, including a process for molding a combustion chamber assembly, comprising the following steps:

[0012] Step 1: Prepare ablation-resistant EPDM rubber material by mixing and refining the base rubber, reinforcing components, flame retardant fillers, reinforcing fillers, processing aids, interface modifiers and vulcanizing agents in a predetermined ratio.

[0013] Step 2: Prepare the insulation layer at the closed end, including the following preheating, loading, and pressing processes, as detailed below:

[0014] A) Preheat the mold: Heat the mold with the closed end on a flat vulcanizing machine and then keep it at a constant temperature.

[0015] B) Loading and mold closing: Wrap the ablation-resistant EPDM rubber material prepared in step one around the surface of the female mold of the mold with the closed end, and then put it into a flat vulcanizing machine for mold closing to generate mold closing material.

[0016] C) Compression molding: The mold material is compressed, and after the erosion-resistant EPDM rubber material is demolded and wiped, a heat insulation layer with closed end is formed.

[0017] Step 3: Prepare the preform mold for the load-bearing shell layer, including preheating, molding, and curing processes, as detailed below:

[0018] D) Mold preheating: The mold for the load-bearing shell layer is heated in an oven and then kept at that temperature.

[0019] E) Winding: The insulation layer of the closed end prepared in step two and the overlap of the closed end are chamfered by 10mm, and adhesive is brushed on the chamfered part. The insulation layer and the closed end are bonded together. The bonded insulation layer and the closed end are then bonded together again on the mold surface of the load-bearing shell layer. A simulated closed end is placed on the winding section of the mold of the load-bearing shell layer. The simulated closed end is then clamped on the fiber winding machine for simulation. After confirming the simulation program, the simulation program is exported to the winding machine for winding. After the winding is completed, it is cut and separated along the cross section, and the simulated closed end is removed to form a simulated load-bearing shell layer.

[0020] F) Curing and molding: Place the wound simulated load-bearing shell layer in an oven and raise it from room temperature to 160℃-180℃ within 2-3 hours. Maintain the temperature at 160℃-180℃ for 4-6 hours, and then allow it to cool naturally to room temperature before demolding to form a pre-made mold of the load-bearing shell layer.

[0021] Step 4: Prepare the load-bearing shell layer by compression molding, which includes preheating, molding, and pressing processes, as detailed below:

[0022] G) Mold preheating: Place the preform mold of the load-bearing shell layer prepared in step three on the press and heat it to 80°C for the first time, and keep it warm for 1-2 hours.

[0023] H) Loading and molding: Wipe the release agent on the surface of the female mold and male mold of the pre-product mold of the load-bearing shell layer 2-3 times, weigh an appropriate amount of high silica fiber / phenolic resin, fill it into the forming surface of the female mold, and after filling, heat it a second time in the flat vulcanizing machine and close the mold to form secondary molding material.

[0024] I) Press molding: The secondary molded material is placed in an oven for a third heating and then naturally cooled to room temperature before demolding to form a load-bearing shell layer;

[0025] Step 5: Machining and bonding of combustion chamber components. Machining the outer dimensions of the load-bearing shell layer formed in Step 4 according to the design drawings. Bonding the reinforcing connection structure and the heat insulation layer to the shell respectively.

[0026] Step six: Inspection, perform dimensional inspection;

[0027] Step 7, Test: Perform a hydrostatic test on the combustion chamber assembly shell that passed the dimensional inspection in Step 6. The pressure range of the hydrostatic test is 12MPa-14MPa.

[0028] Step 8: Milling holes. After the test in Step 7 is passed, mill the spray holes at the tail end of the combustion chamber assembly housing.

[0029] Optionally, the ablation-resistant EPDM rubber material in step one is composed of the following materials by mass percentage: 3%-8% reinforcing component, 13%-20% flame retardant filler, 12%-20% reinforcing filler, 3.3%-11% processing aid, 3%-8% interface modifier, and 3%-8% vulcanizing agent, with the balance being basic rubber, and the sum of the mass percentages of all components being 100%.

[0030] The basic rubber is ethylene propylene diene monomer (EPDM) rubber.

[0031] The reinforcing component is a fiber material;

[0032] The flame-retardant filler comprises a metal hydroxide;

[0033] The reinforcing filler comprises fumed silica;

[0034] The processing aid comprises one or a mixture of two of stearic acid and zinc hydroxide;

[0035] The interface modifier includes a silane coupling agent;

[0036] The vulcanizing agent contains an organic peroxide;

[0037] The above components are mixed in proportion, heated and fired, and then stirred evenly to form an ablation-resistant EPDM rubber material.

[0038] Optionally, in step two, the mold for forming the closed end is heated to 80°C during the preheating process in the flat vulcanizing machine, and the heat preservation time is not less than 1 hour.

[0039] In step two, the temperature inside the flat vulcanizing machine during loading and mold closing is 160℃-180℃, and the pressure holding time is 1h-2h.

[0040] The wiping material in step two is ethyl acetate.

[0041] Optionally, in step three, the fiber winding machine is set with a winding tension of 30-50N, a yarn speed of 0.2m / s-0.4m / s, a winding angle of 90°, and a spiral winding angle that alternates between ±30° and ±60°. After setting these parameters, a simulation is performed.

[0042] Optionally, in step four, the temperature of the oven during the first heating is raised to 80℃-90℃ after 1 hour, and the holding time is 1-2 hours.

[0043] The second heating is to raise the temperature to 110℃-120℃ after the first heating for 2 hours, and the holding time is 1-2 hours.

[0044] The third heating is a further heating process of 2-3 hours after the second heating, with the final temperature controlled at 180℃-200℃.

[0045] Optionally, in step five, epoxy adhesive is used for bonding, and after bonding, it is placed at room temperature for 24-48 hours to complete curing.

[0046] Optionally, the dimensional inspection in step six involves ultrasonic testing of the bonding interface followed by CT scan to assess the internal quality of the composite material.

[0047] The beneficial effects of this application are as follows:

[0048] 1. This invention provides a multi-layer composite shell structure design and material innovation. By employing a multi-layer composite structure consisting of a load-bearing shell layer, a heat-insulating protective layer, and an auxiliary heat-insulating layer, combined with the application of ablation-resistant EPDM rubber material, the structural strength and ablation resistance of the ignition device are significantly improved. Specifically, the load-bearing shell layer is formed by glass fiber winding, and a gradient thickening design at the closed end (the cross-sectional thickness increases as the diameter decreases) optimizes stress distribution and solves the problem of easy cracking at the ends of traditional shells. Simultaneously, the synergistic effect of the inner and outer multi-layer heat-insulating materials (auxiliary heat-insulating layer, heat-insulating protective layer, and heat-insulating lining layer) effectively blocks the thermal shock of high-temperature combustion gases to the shell.

[0049] 2. This invention provides a breakthrough in the integrated molding process for closed-end ends, innovatively proposing a curved transition structure for closed ends and a compression molding process using ablation-resistant materials. Using a specific ratio of ablation-resistant EPDM rubber (containing reinforcing fibers, metal hydroxide flame-retardant fillers, and fumed silica reinforcing fillers), combined with a staged heating and pressing process (110℃-120℃ pressurization and heat preservation for 1-2 hours), dense molding of complex curved surface structures is achieved. Through chamfered bonding design and optimized simulated winding program, seamless connection between the closed end and the load-bearing shell layer is ensured, improving interface bonding strength. Furthermore, the overall structural integrity is maintained even after milling the tail nozzles, solving the technical bottleneck of easy leakage in traditional split-type ends.

[0050] 3. This invention provides synergistic optimization of fiber winding and curing processes. For combustion chamber component molding, it develops glass fiber winding tension control (30-50N), angle adjustment (winding angle of 90°, with alternating spiral winding angles of ±30° and ±60°), and curing processes. By simulating dynamic winding path planning at the closed end, combined with oven gradient curing (heating to 180℃-200℃ in 2 hours, holding for 4-6 hours), the porosity of the composite material is reduced, and the interlaminar shear strength is improved. Combined with hydrostatic testing (12-14MPa) and ultrasonic / CT non-destructive testing technology, the pressure-bearing capacity of the shell is ensured, significantly improving product reliability and batch consistency. Attached Figure Description

[0051] Figure 1 A schematic diagram of the ignition housing structure of the rocket ignition device provided by the present invention;

[0052] Figure 2 The molding method of the rocket-type ignition device provided by the present invention;

[0053] In the diagram: 1. Cover assembly; 2. Combustion chamber assembly; 3. Outer shell; 4. Insulating lining; 5. Ignition charge receiving structure; 6. Load-bearing shell layer; 7. Auxiliary insulation layer; 8. Insulating protective layer; 9. Reinforced connection structure; 10. Closed end. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Example 1:

[0056] Please refer to Figure 1 As shown, a rocket-type ignition device is prepared according to the following steps, including: a cover assembly 1 and a combustion chamber assembly 2, wherein the cover assembly 1 and the combustion chamber assembly 2 are sealed together, and the cover assembly and the combustion chamber assembly can be connected by threads;

[0057] The cover assembly 1 consists of an outer shell 3, a heat insulation liner 4, and an ignition charge receiving structure 5. The ignition charge receiving structure 5 is embedded in one end of the outer shell 3 through the heat insulation liner 4.

[0058] The combustion chamber assembly 2 is configured as a multi-layer composite shell structure, which includes a load-bearing shell layer 6. The outer surface of the load-bearing shell layer 6 is provided with a reinforcing connection structure 9. The inner wall of the load-bearing shell layer 6 has a heat insulation protective layer 8. An auxiliary heat insulation layer 7 is also provided on the outer side of the load-bearing shell layer 6 near the outer shell 3.

[0059] The reinforcing connection structure 9 is disposed on the outer surface of the load-bearing shell layer 6. The reinforcing connection structure 9 is a ring-shaped fitting that is interference-fitted into the middle of the load-bearing shell layer 6.

[0060] The combustion chamber assembly 2 is equipped with a closed end 10, which is configured as a curved transition structure to reduce airflow disturbance during ignition.

[0061] The closed end 10 is provided with at least three axisymmetrically distributed spray holes with a diameter of 4-12 mm.

[0062] The auxiliary heat insulation layer 7, the heat insulation protection layer 8, and the heat insulation lining layer 4 are all made of ablation-resistant EPDM rubber material.

[0063] The load-bearing shell layer 6 is formed by winding glass fiber, and the load-bearing shell layer 6 winds two parts: the outer shell of the column and the closed end 10. The cross-sectional thickness of the load-bearing shell layer 6 at the closed end 10 increases as the diameter of the closed end 10 decreases.

[0064] The load-bearing shell layer 6 has an outer diameter of 100mm and a cylindrical section thickness of 3mm. The thickness of the closed end 10 is naturally accumulated during fiber winding without mechanical processing. The cylindrical section thickness of the auxiliary heat insulation layer 7 is 2mm.

[0065] The natural accumulation of the load-bearing shell layer 6 during fiber winding around the closed end 10 will cause the load-bearing shell layer 6 to accumulate thickness at the closed end 10, and the winding layer will gradually thicken as the cross-sectional diameter of the closed end 10 gradually decreases. Figure 1 As shown, this winding optimizes the stress distribution, thereby increasing the load-bearing capacity of the load-bearing shell layer 6 for the end of the closed end 10.

[0066] Please refer to Figure 2 As shown, the load-bearing shell layer 6 is formed by winding glass fiber, and the auxiliary heat insulation layer 7 and the heat insulation protection layer 8 are made of ablation-resistant EPDM rubber material. The specific steps are as follows:

[0067] Step 1: Prepare ablation-resistant EPDM rubber material. The ablation-resistant EPDM rubber material has the following weight percentages: stearic acid 3.4%, fiber 6%, zinc hydroxide 7%, coupling agent 3%, aluminum hydroxide 20%, DCP 6%, silica 17%, and the balance is EPDM rubber and unavoidable impurities. All materials are refined on a two-roll mill according to the proportions to prepare the ablation-resistant EPDM rubber material.

[0068] Step 2: Pressing the insulation layer of the erosion-resistant EPDM rubber insulation layer at the sealed end 10, including the following preheating, loading, and pressing processes, as detailed below:

[0069] A) Preheat the mold: Heat the molding mold of the closed end 10 on a flat vulcanizing machine and then keep it at a constant temperature. The flat vulcanizing machine is heated to 80°C and the holding time is 1.5 hours.

[0070] B) Loading and mold closing: Wrap the ablation-resistant EPDM rubber material prepared in step one around the surface of the female mold of the heat insulation layer forming mold of the closed end 10, and then put it into a flat vulcanizing machine for mold closing to form mold closing material.

[0071] C) Press molding: Press the molded material, and wait for the erosion-resistant EPDM rubber material to be demolded and wiped to form the heat insulation layer of the closed end 10. The temperature of the flat vulcanizing machine in this step is 160°C, and the pressure and heat preservation time is 1 hour.

[0072] Step 3: Prepare the preform mold for the load-bearing shell layer 6, including preheating, molding, and curing processes, as detailed below:

[0073] D) Mold preheating: Heat the mold of the load-bearing shell layer 6 to 60°C in an oven and keep it at that temperature for 3 hours.

[0074] E) Winding: Chamfer the overlap of the insulation layer and the closed end 10 prepared in step two by 10mm, and apply adhesive to the chamfered area. Bond the insulation layer and the closed end 10 together, and then bond the bonded insulation layer and the closed end 10 together to the mold surface of the load-bearing shell layer 6. Place the simulated closed end 10 on the winding section of the mold of the load-bearing shell layer 6, and then clamp the simulated closed end 10 onto the fiber winding machine for simulation. After confirming the simulation program, export the simulation program to the winding machine for winding. After the winding is completed, cut off the simulated closed end 10 along the cross-section of the simulated closed end 10 and remove the simulated closed end 10.

[0075] The winding tension is set to 40N, the yarn speed to 0.35m / s, the winding angle to 90°, and the spiral winding angle to alternate between ±30° and ±60° in the software and the simulation is performed. After ensuring that there are no errors, the winding program is exported to the winding machine for winding. After the winding is completed, the fiber is cut along the end face of the simulated closed end 10 and the simulated closed end 10 is removed to form the simulated load-bearing shell layer 6.

[0076] Tests showed that the alternating winding angle design increased circumferential strength by 35% and axial strength by 22%.

[0077] F) Curing and molding: The wound simulated load-bearing shell layer 6 is placed in an oven and heated from room temperature to 160°C within 2.5 hours. It is then kept at 160°C for 4 hours and allowed to cool naturally to room temperature before demolding to form a pre-made mold of the load-bearing shell layer 6.

[0078] Step four, prepare the load-bearing shell layer 6, which includes preheating, molding, and pressing processes, as detailed below:

[0079] G) Mold preheating: Place the preform mold of the load-bearing shell layer 6 prepared in step 3 on the press and heat it to 80°C for the first time, and keep it warm for 1.5 hours;

[0080] H) Loading and molding: Wipe the release agent three times on the surfaces of the female and male molds of the pre-made mold of the load-bearing shell layer 6. Weigh an appropriate amount of high-silica fiber / phenolic resin and fill it into the female mold forming surface of the pre-made mold of the load-bearing shell layer 6. After filling, heat it a second time in the flat vulcanizing machine and mold it to form a secondary molding material. The secondary molding material is used to form the load-bearing shell layer 6. The second heating time is to raise the temperature to 110°C after 2 hours and keep it at that temperature for 1 hour.

[0081] I) Press molding: The secondary molded material is placed in an oven for a third heating. The third heating is based on the temperature after the second heating and heat preservation, and then the temperature is raised to 190°C for 2 hours and kept at that temperature for 2 hours. After naturally cooling to room temperature, the material is demolded to form the load-bearing shell layer 6.

[0082] Step 5: Machining and bonding of combustion chamber component 2. The outer dimensions of the load-bearing shell layer 6 formed by molding in step 4 are machined according to the design drawings. The reinforcing connection structure 9 and the heat insulation protection layer 8 are bonded to the shell with epoxy adhesive. After bonding, the shell is placed at room temperature for 30 hours to cure and form.

[0083] Step 6, Inspection: Perform dimensional inspection, use ultrasonic testing to inspect the bonding interface, and use CT to detect the internal quality of the composite material.

[0084] Step 7, Test: Perform a hydrostatic test on the combustion chamber assembly 2 shell, which has passed the dimensional inspection in Step 6. The hydrostatic strength is 12 MPa.

[0085] Step 8: Milling holes. After the test in Step 7 is passed, mill the spray holes at the tail end of the combustion chamber assembly 2 housing. The spray holes are 4-10mm in size.

[0086] Example 2:

[0087] The rocket-type ignition device is prepared according to the following steps: the outer diameter of the load-bearing shell layer 6 is 130 mm, the thickness of the cylindrical section is 4 mm, and the thickness of the closed end 10 is naturally accumulated during fiber winding without mechanical processing. The thickness of the cylindrical section of the auxiliary heat insulation layer 7 is 2.5 mm. The load-bearing shell layer 6 is formed by winding glass fiber, and the auxiliary heat insulation layer 7 uses an ablation-resistant EPDM rubber ablation-resistant layer. The specific steps are as follows:

[0088] Step 1: Prepare ablation-resistant EPDM rubber material. The ablation-resistant EPDM rubber material is composed of the following by weight percentage: stearic acid 3.6%, fiber 7%, zinc hydroxide 4%, coupling agent 5%, aluminum hydroxide 18%, DCP 5%, silica 20%, with the balance being EPDM rubber and unavoidable impurities. All materials are refined in proportion on an open mill to prepare the ablation-resistant EPDM rubber material.

[0089] Step 2: Prepare the insulation layer of the closed end 10, including the following preheating, loading and pressing processes, as detailed below:

[0090] A) Preheat the mold: Heat the mold of the closed end 10 on a flat vulcanizing machine and keep it at a temperature of 80°C for 2 hours.

[0091] B) Loading and mold closing: Wrap the ablation-resistant EPDM rubber material prepared in step one around the surface of the female mold of the mold at the closed end 10, and then place it into a flat vulcanizing machine for mold closing to form a mold closing material.

[0092] C) Press molding: Press the molded material, and wait for the erosion-resistant EPDM rubber material to be demolded and wiped to form an insulation layer. The temperature of the flat vulcanizing machine is 170°C, and the pressure and heat preservation time is 2 hours.

[0093] Step 3: Prepare the preform mold for the load-bearing shell layer 6, including preheating, molding, and curing processes, as detailed below:

[0094] D) Mold preheating: Heat the mold of the load-bearing shell layer 6 to 60°C in an oven and keep it at that temperature for 3.5 hours;

[0095] E) Winding: The overlap between the insulation layer and the closed end 10 prepared in step two is chamfered by 10mm, and adhesive is applied to the chamfered area. The insulation layer and the closed end 10 are then bonded together. The bonded insulation layer and closed end 10 are then bonded again to the mold surface of the load-bearing shell layer 6. A simulated closed end 10 is placed on the winding section of the mold in the load-bearing shell layer 6. The simulated closed end 10 is then clamped onto the fiber winding machine for simulation. After confirming the simulation program, the simulation program is exported to the winding machine. The yarn is wound on a winding machine. After winding is completed, the simulated closed end 10 is removed by cutting off the limit along the cross-section of the simulated closed end 10. The winding tension is set to 40N, the yarn speed to 0.35m / s, the winding angle to 90°, and the spiral winding angle to alternate between ±30° and ±60° in the software and the simulation is performed. After ensuring that there are no errors, the winding program is exported to the winding machine for winding. After winding is completed, the fiber is cut along the end face of the simulated closed end 10 and the simulated closed end 10 is removed to form the simulated load-bearing shell layer 6.

[0096] F) Curing and molding: The wound simulated load-bearing shell layer 6 is placed in an oven and heated from room temperature to 180°C within 3 hours. It is then kept at 180°C for 5 hours and naturally cooled to room temperature before demolding to form a pre-made mold of the load-bearing shell layer 6.

[0097] Step 4: Prepare the load-bearing shell layer 6 by molding, including preheating, molding, and pressing processes, as detailed below:

[0098] G) Mold preheating: Place the preform mold of the load-bearing shell layer 6 prepared in step 3 on the press and heat it to 90°C for the first time, and keep it warm for 2 hours.

[0099] H) Loading and molding: Wipe the release agent twice on the surfaces of the female and male molds of the pre-product mold of the load-bearing shell layer 6. Weigh an appropriate amount of high-silica fiber / phenolic resin and fill it into the female mold forming surface of the pre-product mold of the load-bearing shell layer 6. After filling, perform a second heating and mold closing in a flat vulcanizing machine to form a secondary molding material. The second heating time is to raise the temperature to 120°C for 2 hours and keep it at that temperature for 2 hours. The secondary molding material is used to form the load-bearing shell layer 6.

[0100] I) Press molding: The secondary molded material is placed in an oven and heated for the third time. The temperature of the third heating is based on the temperature of the second heating. The temperature is increased for 3 hours and then heated to 200°C and held for 3 hours. After naturally cooling to room temperature, the material is demolded to form the load-bearing shell layer 6.

[0101] Step 5: Machining and bonding of combustion chamber component 2. The outer dimensions of the load-bearing shell layer 6 formed by molding in step 4 are machined according to the design drawings. The reinforcing connection structure 9 and the heat insulation protection layer 8 are bonded to the shell using epoxy adhesive. After bonding, the shell is placed at room temperature for 35 hours to cure and form.

[0102] Step 6, Inspection: Perform dimensional inspection, use ultrasonic testing to inspect the bonding interface, and use CT to detect the internal quality of the composite material.

[0103] Step 7, Test: Perform a hydrostatic test on the combustion chamber assembly 2 shell, which has passed the dimensional inspection in Step 6. The hydrostatic strength is 12 MPa.

[0104] Step 8: Milling holes. After the test in Step 7 is passed, mill the spray holes at the tail end of the combustion chamber assembly housing. The spray holes are 4-10mm in size.

[0105] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A rocket-type ignition device, characterized in that, include: A cover assembly and a combustion chamber assembly, wherein the cover assembly and the combustion chamber assembly are sealed together. The cover assembly consists of an outer shell, a heat insulation liner, and an ignition charge receiving structure, wherein the ignition charge receiving structure is embedded in one end of the outer shell through the heat insulation liner. The combustion chamber assembly is configured as a multi-layer composite shell structure, which includes a load-bearing shell layer. The outer surface of the load-bearing shell layer is provided with a reinforcing connection structure. The inner wall of the load-bearing shell layer has a heat insulation protective layer. An auxiliary heat insulation layer is also provided on the outer side of the load-bearing shell layer near the outer shell. The combustion chamber assembly is fitted with a closed end cap, which is configured as a curved transition structure to reduce airflow disturbance during ignition. The closed end is provided with at least three axisymmetrically distributed nozzles; The auxiliary heat insulation layer, the heat insulation protection layer, and the heat insulation lining are all made of ablation-resistant EPDM rubber material; The load-bearing shell layer is formed by winding glass fiber, and the cross-sectional thickness of the load-bearing shell layer at the closed end increases as the diameter of the closed end decreases.

2. The molding method of a rocket-type ignition device according to claim 1, characterized in that, The process for forming the combustion chamber assembly includes the following steps: Step 1: Prepare ablation-resistant EPDM rubber material by mixing and refining the base rubber, reinforcing components, flame retardant fillers, reinforcing fillers, processing aids, interface modifiers and vulcanizing agents in a predetermined ratio. Step 2: Prepare the insulation layer at the closed end, including the following preheating, loading, and pressing processes, as detailed below: A) Preheat the mold: Heat the mold with the closed end on a flat vulcanizing machine and then keep it at a constant temperature. B) Loading and mold closing: Wrap the ablation-resistant EPDM rubber material prepared in step one around the surface of the female mold of the mold with the closed end, and then put it into a flat vulcanizing machine for mold closing to generate mold closing material. C) Compression molding: The mold material is compressed, and after the erosion-resistant EPDM rubber material is demolded and wiped, a heat insulation layer with closed end is formed. Step 3: Prepare the preform mold for the load-bearing shell layer, including preheating, molding, and curing processes, as detailed below: D) Mold preheating: The mold for the load-bearing shell layer is heated in an oven and then kept at that temperature. E) Winding: The insulation layer of the closed end prepared in step two and the overlap of the closed end are chamfered by 10mm, and adhesive is brushed on the chamfered part. The insulation layer and the closed end are bonded together. The bonded insulation layer and the closed end are then bonded together again to the mold surface of the load-bearing shell layer. A simulated closed end is placed in the winding section of the mold of the load-bearing shell layer. The simulated closed end is then clamped onto the fiber winding machine for simulation. After confirming the simulation program, the simulation program is exported to the winding machine for winding. After the winding is completed, the simulated closed end is cut and separated along the cross section to form a simulated load-bearing shell layer. F) Curing and molding: Place the wound simulated load-bearing shell layer in an oven and raise it from room temperature to 160℃-180℃ within 2-3 hours. Maintain the temperature at 160℃-180℃ for 4-6 hours, and then allow it to cool naturally to room temperature before demolding to form a pre-made mold of the load-bearing shell layer. Step 4: Prepare the load-bearing shell layer by compression molding, which includes preheating, molding, and pressing processes, as detailed below: G) Mold preheating: Place the preform mold of the load-bearing shell layer prepared in step three on the press and heat it to 80°C for the first time, and keep it warm for 1-2 hours. H) Loading and molding: Wipe the release agent on the surfaces of the female and male molds of the pre-product mold of the load-bearing shell layer 2-3 times. Weigh an appropriate amount of high-silica fiber / phenolic resin and fill it into the forming surface of the female mold of the pre-product mold of the load-bearing shell layer. After filling, heat it a second time in the flat vulcanizing machine and mold it to form a secondary molding material. The secondary molding material is used to form the load-bearing shell layer. I) Press molding: The secondary molding material is placed in an oven for a third heating and then naturally cooled to room temperature before demolding to form a load-bearing shell layer; Step 5: Machining and bonding of combustion chamber components. Machining the outer dimensions of the load-bearing shell layer formed in Step 4 according to the design drawings. Bonding the reinforcing connection structure and the heat insulation layer to the shell respectively. Step six: Inspection, perform dimensional inspection; Step 7, Test: Perform a hydrostatic test on the combustion chamber assembly shell that passed the dimensional inspection in Step 6. The pressure range of the hydrostatic test is 12MPa-14MPa. Step 8: Milling holes. After the test in Step 7 is passed, mill the spray holes at the tail end of the combustion chamber assembly housing. The ablation-resistant EPDM rubber material in step one is composed of the following materials by mass percentage: 3%-8% reinforcing component, 13%-20% flame retardant filler, 12%-20% reinforcing filler, 3.3%-11% processing aid, 3%-8% interface modifier, and 3%-8% vulcanizing agent, with the balance being basic rubber. The sum of the mass percentages of all components is 100%. The basic rubber is ethylene propylene diene monomer (EPDM) rubber. The reinforcing component is a fiber material; The flame-retardant filler comprises a metal hydroxide; The reinforcing filler comprises fumed silica; The processing aid comprises one or a mixture of two of stearic acid and zinc hydroxide; The interface modifier includes a silane coupling agent; The vulcanizing agent contains an organic peroxide; The above components are mixed in proportion, heated and fired, and then stirred evenly to form an ablation-resistant EPDM rubber material.

3. The molding method of a rocket-type ignition device according to claim 2, characterized in that, In step two, the mold for forming the closed end is heated to 80°C during the preheating process in the flat vulcanizing machine, and the heat preservation time is not less than 1 hour. In step two, the temperature inside the flat vulcanizing machine during loading and mold closing is 160℃-180℃, and the pressure holding time is 1h-2h. The wiping material in step two is ethyl acetate.

4. The molding method of a rocket-type ignition device according to claim 2, characterized in that, In step three, the fiber winding machine is set with a winding tension of 30-50N, a yarn speed of 0.2m / s-0.4m / s, a winding angle of 90°, and a spiral winding angle that alternates between ±30° and ±60°. After the settings are completed, a simulation is performed.

5. The molding method of a rocket-type ignition device according to claim 2, characterized in that, In step four, the temperature of the oven for the first heating is raised to 80℃-90℃ after 1 hour, and the holding time is 1-2 hours. The second heating is to raise the temperature to 110℃-120℃ after the first heating for 2 hours, and the holding time is 1-2 hours. The third heating is a further heating process of 2-3 hours after the second heating, with the final temperature controlled at 180℃-200℃.

6. The molding method of a rocket-type ignition device according to claim 2, characterized in that, In step five, epoxy adhesive is used for bonding, and after bonding, it is left at room temperature for 24-48 hours to complete curing.

7. The molding method of a rocket-type ignition device according to claim 2, characterized in that, The dimensional inspection in step six involves ultrasonic testing of the bonding interface followed by CT scans to assess the internal quality of the composite material.

Images