Intensive micro cylinder structure heat insulation layer forming method and device

Abstract

The invention relates to the technical field of heat insulation layer forming, in particular to a forming method and device for an intensive micro cylinder structure heat insulation layer, the device comprises a base, and the base is provided with a concave cavity used for bearing a combustion chamber shell; the mandrel is vertically arranged in the combustion chamber shell; and the upper die comprises a pressure head for pressing the heat insulation layer raw material into the inner sealing head end of the combustion chamber shell, and blind holes for forming a plurality of cylinder structures are formed in the pressure head. According to the method, the intensive micro cylinder structure heat insulation layer is firstly processed at the end socket end through the pressure head, and then the straight section heat insulation layer is formed by adopting the vulcanization process, so that the problem of forming the intensive micro cylinder structure heat insulation layer is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation layer forming, and particularly relates to a forming method and device for an insulation layer with a dense micro-column structure. Background Art

[0002] The insulation layer is an important part of a solid rocket motor. The material is generally ethylene propylene diene monomer (EPDM). The common insulation layer structure is a cylindrical thin-wall structure, whose outer shape is consistent with the inner wall of the combustion chamber shell, and most of its inner surfaces are flat without special structures. The forming method of such an insulation layer is usually completed in two steps. First, a mold is used to press a preform of the insulation layer, and then an airbag is used to apply pressure to bond the preform to the inner wall of the combustion chamber shell for vulcanization forming.

[0003] With the continuous development of engine technology, various complex structure insulation layers have emerged. In the research and development task of a certain small engine, according to the task requirements, a large number of micro-column structures are designed at the head part of the insulation layer. Among them, the bottom diameter of each column structure is 2.5 mm, the height is 3.5 mm, and the top diameter is 1.5 mm, which are used to position and install micro grain charges. The insulation layer structure is as Figures 1 to 2 shown. In the dense micro-column insulation layer 1 located in the combustion chamber shell 2, a large number of micro-column structures are provided in the insulation layer at the head part of the combustion chamber shell 2. It is difficult to meet the forming requirements by using traditional forming techniques.

[0004] For the above-mentioned insulation layer with a dense micro-column structure, when using the existing forming techniques, the following problems exist:

[0005] When adopting the overall die pressing forming scheme, since the thickness of the straight section of the insulation layer is too thin to provide a draft angle, after overall die pressing, the mold cannot be demolded, as Figure 3 shown;

[0006] When adopting the external segmented die pressing forming and then pasting inside the shell scheme, during bonding, when the airbag directly applies pressure, the micro-columns will be damaged, as Figure 4 shown. If a transition piece is used to protect the column structure, the holes on the transition piece cannot be aligned with the columns on the insulation layer, and thus cannot be assembled.

[0007] Based on this, the present invention provides a forming method and device for an insulation layer with a dense micro-column structure in order to solve the forming problem of the insulation layer with a dense micro-column structure. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a method and a device for forming an insulating layer of a dense micro-column structure. Compared with the existing forming technology for insulating layer forming, the present invention solves the following problems: a) Since the straight section of the insulating layer is too thin to provide a draft angle, when using the existing insulating layer forming technology for molding, the mold cannot be demolded. The present invention adopts the idea of space segmentation to solve the demolding problem; b) When bonding, the prior art directly pressurizes with an airbag, and the micro-columns will be damaged. The present invention adopts a segmented pressurization form to solve the pressurization problem; c) For a thin-walled combustion chamber shell, the prior art usually takes external molding of the insulating layer with a mold and then bonds the insulating layer to the inner wall of the shell by airbag pressurization. The present invention provides an overall molding technology for thin-walled combustion chamber shells.

[0009] The first object of the present invention is to provide a device for forming an insulating layer of a dense micro-column structure, including:

[0010] A base, which is provided with a cavity for carrying the combustion chamber shell;

[0011] A mandrel, vertically arranged in the combustion chamber shell, and the mandrel and the combustion chamber shell are coaxial;

[0012] An upper mold, including a pressing head for pressing the insulating layer raw material into the inner head end of the combustion chamber shell, and blind holes for forming a plurality of column structures are arranged at the pressing head;

[0013] Among them, the upper mold is provided with a through hole for the mandrel to pass through. When the upper mold is pressed into the combustion chamber shell, the mandrel is simultaneously inserted into the through hole to position the upper mold.

[0014] Preferably, the shape in the cavity matches the combustion chamber shell; among them, when the insulating layer raw material is pressed into the inner head end of the combustion chamber shell, the combustion chamber shell serves as the lower mold.

[0015] Preferably, an air storage cavity is arranged inside each blind hole, and each blind hole is communicated with the corresponding inner air storage cavity through an exhaust hole.

[0016] Preferably, the blind holes of each main structure are in a conical structure or a cylindrical structure.

[0017] The second object of the present invention is to provide an application of the above device in the forming of an insulating layer of a dense micro-column structure.

[0018] The third object of the present invention is to provide a method for forming an insulating layer of a dense micro-column structure, adopting the above device for forming an insulating layer of a dense micro-column structure, including:

[0019] Transfer the mandrel into the combustion chamber shell, and then integrally install it on the base;

[0020] Cut the ethylene propylene diene monomer (EPDM) rubber into circular rings and strips;

[0021] Put the circular EPDM rubber into the combustion chamber shell, and fill the blind hole of the upper mold pressing head with the strip EPDM rubber;

[0022] After putting the upper mold into the combustion chamber shell, place the whole in a vulcanizer, preheat at 80 - 95 °C for 3 - 6 min. Then, adjust the pressure of the vulcanizer to close the mold. After venting multiple times, close the mold and hold the pressure, and keep the temperature at 150 - 165 °C for 65 - 75 min. Then cool down to 55 - 65 °C and demold, and a dense micro-column structure insulation layer can be obtained at the head end of the combustion chamber shell.

[0023] Preferably, before pressing the film at the head end of the combustion chamber shell, apply an adhesive to the mold pressing part at the head end of the combustion chamber shell and leave it to dry at room temperature for 1 - 2 h.

[0024] Preferably, it also includes the forming of the straight-section insulation layer in the combustion chamber shell, and its forming method includes:

[0025] Use a mold to press multiple straight-section insulation layers;

[0026] Paste the straight-section insulation layer on the inner wall of the straight section in the combustion chamber shell;

[0027] After transferring the front plug cover to the combustion chamber shell, sequentially install the support plate, silica gel ring, and airbag close to the head end, and then install the rear plug cover of the combustion chamber shell; then, place the whole in an oven, inflate the airbag, and heat the oven to 150 - 165 °C and keep the temperature for 65 - 75 min to obtain the straight-section insulation layer in the combustion chamber shell.

[0028] Preferably, during the insulation layer forming process, adjacent straight-section insulation layers are overlapped through inclined chamfers; each straight-section insulation layer overlaps with the flash of the head-end insulation layer.

[0029] Preferably, the support plate is used to isolate the dense micro-column structure insulation layer at the head end to prevent the influence on the dense micro-column structure insulation layer when the airbag is pressurized.

[0030] The present invention has at least the following beneficial effects:

[0031] The present invention provides a forming method and device for a dense micro-column structure insulation layer. This method mainly includes three parts. First, the combustion chamber is divided into two parts, namely the head end and the straight section. The insulation layer at the head end is directly molded onto the shell using a mold. Since there is no straight section, easy demolding can be achieved. Second, the straight section is pasted onto the inner wall of the shell in a patch manner. When the airbag is pressurized, a "partition" is used to separate the front and rear sections, such as Figure 5As shown in the figure, only the straight section is pressurized to avoid damage to the micro-cylinders. When molding the insulation layer at the sealing head end, the formed flash is not cleaned and used as the bonding and lapping area for the straight section. Description of the Drawings

[0032] Figure 1 It is a structural diagram of the insulation layer;

[0033] Figure 2 It is a three-dimensional model of the insulation layer for the dense micro-cylinders;

[0034] Figure 3 The straight section of the insulation layer has no draft angle;

[0035] Figure 4 During bonding, when the airbag is pressurized, the cylinder structure will be damaged;

[0036] Figure 5 It is for space segmentation;

[0037] Figure 6 It is a forming die for the insulation layer at the sealing head end;

[0038] Figure 7 It is the upper die assembly;

[0039] Figure 8 It is the first scheme of the indenter blind hole structure;

[0040] Figure 9 It is the second scheme of the indenter blind hole structure;

[0041] Figure 10 It is the vulcanization tooling for bonding the straight section insulation layer;

[0042] Figure 11 It is a forming die for the straight section insulation layer;

[0043] Figure 12 It is Figure 11 The left view of the forming die for the straight section insulation layer. Detailed Implementation Modes

[0044] In order to elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will be described in detail in combination with the embodiments.

[0045] The purpose of the present invention is to provide a forming method for the insulation layer of a dense micro-cylinder structure and the adopted device. The main contents of the present invention include: a) space segmentation and local pressurization technology; b) integral molding technology for the dense micro-cylinders; c) synthetic joint treatment technology.

[0046] For the insulation layer of the dense micro-column structure, in view of the problems existing in the existing forming technologies, the present invention proposes the following solutions: a) The combustion chamber is divided into two parts, one part is the head end, and the other part is the straight section. The insulation layer of the head end is directly molded onto the shell by a mold. Since there is no straight section, easy demolding can be achieved; b) The straight section is pasted into the shell by a patch method. When the airbag is pressurized, a "partition" is used to separate the front and rear sections. As shown in the partial enlarged view in Figure 5 and Figure 5 shown, only the straight section is pressurized to avoid damage to the micro-columns; c) When the insulation layer of the head end is molded, the forming flash is not cleaned and serves as the bonding and overlapping area for the straight section.

[0047] It should be noted that the insulation layer of this structure is mainly applied to small solid rocket motors. At the present stage when the intelligent technology is developing unprecedentedly, small solid rocket motors have an important strategic position, and the forming technology of the insulation layer with the function of positioning dense micro-charge columns inside them has also become a key technology.

[0048] In order to realize the forming of the insulation layer at the head end, the present invention provides a forming device for the insulation layer of the dense micro-column structure. Refer to Figures 6 to 9 shown, including:

[0049] A base 5, which is provided with a concave cavity for carrying the combustion chamber shell;

[0050] A mandrel 6, which is vertically arranged inside the combustion chamber shell, and the mandrel 6 is coaxial with the combustion chamber shell;

[0051] An upper mold 3, including a pressing head 9 for pressing the insulation layer raw material into the head end inside the combustion chamber shell, and blind holes for forming a plurality of column structures are arranged at the pressing head;

[0052] Wherein, the upper mold 3 is provided with a through hole for the mandrel 6 to penetrate. When the upper mold 3 is pressed into the combustion chamber shell, the mandrel 6 is simultaneously inserted into the through hole to position the upper mold 3.

[0053] In the present invention, since the outer shape of the combustion chamber shell belongs to a cylindrical structure, the concave cavity for carrying the combustion chamber shell opened on the base also belongs to a cylindrical structure. That is, when forming the insulation layer of the dense micro-column structure, the combustion chamber shell is used as the lower mold, and the insulation layer is formed on the lower mold by the pressing of the upper mold.

[0054] It should be noted that after the combustion chamber shell is placed as the lower mold in the concave cavity of the base, the head end of the combustion chamber shell faces the concave cavity. In order to fix the combustion chamber shell in the concave cavity, the mandrel is vertically arranged inside the combustion chamber shell, and the mandrel facing the bottom of the concave cavity is fixed to the base 5 by a nut 7. At the same time, at the open end of the concave cavity and inside the concave cavity, a retaining ring 4 is sleeved, and the combustion chamber shell is fixed in the concave cavity by the retaining ring.

[0055] Wherein, the shape in the concave cavity matches the combustion chamber shell; when the raw material of the thermal insulation layer is pressed into the head end of the combustion chamber shell, the combustion chamber shell serves as the lower mold.

[0056] See Figures 8 to 9 As shown, a gas storage cavity is provided inside each of the blind holes. Each blind hole communicates with the corresponding inner gas storage cavity through an exhaust hole. The blind holes of each main structure are in a conical structure or a cylindrical structure.

[0057] In this embodiment, for such a dense columnar thermal insulation layer, when the diameter of the combustion chamber shell increases and the operating space increases, in the forming die for the head end thermal insulation layer of the combustion chamber shell, fine exhaust holes and gas storage cavities can be designed at the top of the upper die pressing head. Figure 8 As shown, before die pressing, it is not necessary to invert the upper die and pre-fill the adhesive material in the pressing head hole. After the head end thermal insulation layer is formed, there are small flash edges at the top of the micro-columns, which can be cleaned manually later.

[0058] In addition, the surface of the column in the present invention is actually a conical surface, with a bottom diameter of 2.5 mm and a top diameter of 1.5 mm. If the conical surface is changed to a cylindrical surface or other cross-sections, such as Figure 9 As shown, it can still be formed by the method described in the present invention.

[0059] The present invention provides an application of the above device in the forming of a dense micro-column structure thermal insulation layer.

[0060] The present invention provides a method for forming a dense micro-column structure thermal insulation layer. As shown in FIGS. 6-9, the above-mentioned forming device for a dense micro-column structure thermal insulation layer is adopted, including:

[0061] Transfer the mandrel into the combustion chamber shell, and then install the whole into the base;

[0062] Cut the ethylene propylene diene monomer (EPDM) rubber into circular rings and strips;

[0063] Install the circular EPDM rubber into the combustion chamber shell, and fill the blind holes of the upper die pressing head with the strip-shaped EPDM rubber;

[0064] After installing the upper die into the combustion chamber shell, place the whole in a vulcanizer, preheat at 80-95 °C for 3-6 min, then adjust the pressure of the vulcanizer to perform mold closing. After exhausting several times, perform mold closing and pressure holding, and keep warm at 150-165 °C for 65-75 min, and then cool down to 55-65 °C to perform mold removal, that is, a dense micro-column structure thermal insulation layer is obtained at the head end of the combustion chamber shell.

[0065] Wherein, before die pressing the head end of the combustion chamber shell, an adhesive is also applied to the die pressing part at the head end of the combustion chamber shell and left to dry at room temperature for 1-2 h.

[0066] The present invention further includes the forming of the straight-section heat insulation layer inside the combustion chamber housing, and the forming method includes:

[0067] Using a mold to press multiple straight-section heat insulation layers;

[0068] Pasting the straight-section heat insulation layer onto the inner wall of the straight section inside the combustion chamber housing;

[0069] After transferring the front plug cover into the combustion chamber housing, successively install the support plate, silica gel ring, and airbag close to the head end, and then install the rear plug cover of the combustion chamber housing; then, place the whole in an oven, inflate the airbag, heat the oven to 150 - 165 °C, and keep it warm for 65 - 75 min to obtain the straight-section heat insulation layer inside the combustion chamber housing.

[0070] Specifically, during the forming process of the heat insulation layer, adjacent straight-section heat insulation layers are overlapped through inclined chamfers; the flash of each straight-section heat insulation layer is overlapped with the heat insulation layer at the head end.

[0071] The support plate is used to isolate the heat insulation layer of the dense micro-column structure at the head end and prevent the influence on the heat insulation layer of the dense micro-column structure when the airbag is pressurized.

[0072] In order to further illustrate a forming method of a heat insulation layer of a dense micro-column structure provided by the present invention, it is described with reference to the accompanying drawings.

[0073] (1) The design structure of the forming mold for the heat insulation layer at the head end is as shown in the partial enlarged view in Figure 6 and Figure 6 The upper mold consists of an upper mold body and a punch head, as shown in the partial enlarged view in Figure 7 and Figure 7 the partial enlarged view in.

[0074] The forming process of the heat insulation layer at the head end is as follows:

[0075] a) Sandblasting the bonding surface between the combustion chamber housing and the heat insulation layer, with a sandblasting aging time of 24 h;

[0076] b) Cleaning the bonding surface of the combustion chamber housing, applying a primer, and air-drying at room temperature for 1 h;

[0077] c) Applying an adhesive to the molding part at the head end of the combustion chamber housing, without applying adhesive to the straight section, and air-drying at room temperature for 1 h;

[0078] d) Cleaning the mold with ethyl acetate and preheating it to 90 °C;

[0079] e) Assembling the mold, inserting the mandrel 6 into the combustion chamber housing 2, fixing it with a nut 7, then inserting the whole into the base 5, and then covering with a retaining ring 4;

[0080] f) Prepare materials. Cut the ethylene propylene diene monomer (EPDM) rubber into a circular ring shape with an outer diameter of 45 mm, an inner diameter of 15 mm, a thickness of 4.5 mm, and a quantity of 2 pieces, and into a strip shape with dimensions of 2 mm × 2 mm × 180 mm. The total weight is strictly controlled to be 15 g ± 0.3 g.

[0081] g) Load materials. Place the circular EPDM rubber ring into the combustion chamber housing. Invert the upper mold 3, then fill the blind hole of the pressure head 9 with the strip-shaped EPDM rubber and compact it. Load the remaining strip-shaped material into the combustion chamber.

[0082] h) Install the upper mold into the combustion chamber housing. Place the entire mold on the flat vulcanizing machine. Heat the flat vulcanizing machine to 90 °C and preheat it for another 5 minutes.

[0083] i) Adjust the pressure of the flat vulcanizing machine to 2 t, slowly close the mold, exhaust 3 times and then hold the pressure after closing the mold. Raise the temperature to 160 °C and keep it warm for 70 minutes.

[0084] j) Demold when the temperature drops to 60 °C, remove the mandrel, and clean and wipe the mold.

[0085] It should be noted that the main key points of the forming of the head end insulation layer are as follows:

[0086] Integral molding in the combustion chamber: Use the combustion chamber housing as the lower mold and the base as the main load-bearing component. The height of the base is slightly higher than the length of the combustion chamber housing. Ensure that the combustion chamber housing does not deform during integral molding.

[0087] Forming precision control: Both the housing and the base, and the upper mold and the housing adopt positioning at both ends to improve the positioning accuracy.

[0088] Ergonomics compliance: In this forming scheme, the combustion chamber housing is the lower mold. Therefore, the mandrel and the lower mold do not adopt an interference fit but a clearance fit, and are fixed at the bottom with nuts. At the same time, for easy disassembly, the mandrel is designed as a rod-shaped part.

[0089] Demolding structure design: Different from traditional molds, a retaining ring is set at the mold opening position. When opening the mold, the retaining ring limits the combustion chamber housing to ensure the smooth removal of the upper mold.

[0090] Exhaust and flash treatment: The main positioning surfaces of the upper mold and the combustion chamber housing are set at the upper part, and the clearance at the bottom is slightly larger than that at the upper part for exhaust and overflow of glue. At the same time, strictly control the loading amount to ensure that the flash width meets the requirements of later synthesis and lap joint; see Figure 6 As shown in the partial enlarged view in, an exhaust channel is set as the flash after molding, thus meeting the requirements of later lap joint.

[0091] Miniature cylinder forming: Since the miniature cylinder is used to position the propellant charge, there should be no flash on the surface during the forming process. Because the space is narrow, it is impossible to clean the flash on the cylinder later. Therefore, no vent holes should be set at the top of the forming punch. For this reason, before the overall molding, the upper mold of the die is inverted, and the inner hole of the punch is filled with rubber compound externally, and then the overall molding is carried out to ensure the molding quality.

[0092] (2) Design structure of the vulcanization tooling for bonding the straight-section insulation layer is as Figure 8 shown.

[0093] The forming process of the straight-section insulation layer is as follows:

[0094] a) Mold-press the straight-section insulation layer, i.e., ethylene propylene diene monomer (EPDM), using a die as Figures 11 to 12 shown. The die includes: a strip-shaped upper mold 17, a strip-shaped lower mold 18, and positioning pins 19 provided at both ends; the straight-section EPDM will be formed between the strip-shaped upper mold 17 and the strip-shaped lower mold 18. During the forming process, at both ends after the strip-shaped upper mold 17 and the strip-shaped lower mold 18 are closed, they are fixed by the provided positioning pins and cured. Among them, the molded straight-section EPDM has a thickness of 0.5 mm. Refer to the Figure 11 partial enlarged view. Press a step at one end in the length direction to overlap with the head end; refer to the Figure 12 partial enlarged view in. Press chamfered edges on both sides in the width direction for circumferential overlap;

[0095] b) Clean the bonding surface of the straight-section molded part, apply adhesive, and air-dry at room temperature for 1 h;

[0096] c) Apply adhesive to the straight section of the combustion chamber shell, including the flash overlap surface at the head end, and air-dry at room temperature for 1 h;

[0097] d) Install the combustion chamber shell with the pre-molded head insulation layer into the front plug 14, then sequentially install the support plate 15 and the silicone rubber ring 13. After installing the airbag 16, install the rear plug 10 and fix it with bolts 11 and nuts 12;

[0098] e) Put the assembled part into the oven, inflate the airbag to 0.8 MPa, heat the oven to 160 °C, keep it warm for 60 min, and then cool it to room temperature;

[0099] f) Disassemble the tooling, and the product forming is completed.

[0100] It should be noted that the key technologies for bonding the straight-section insulation layer are as follows:

[0101] Design a support plate in the vulcanization tooling. During the straight-section bonding process, when the airbag is pressurized, the support plate protects the already formed miniature cylinder to ensure that the miniature cylinder is not damaged;

[0102] When bonding the straight-section insulation layer, the formed flash at the head end is used as the lap zone to ensure the bonding performance and thickness index of the straight-section insulation layer;

[0103] A silicone rubber ring is placed in the triangular area between the airbag and the support plate to prevent the airbag from bursting during the pressurization process.

[0104] It can be seen that the present invention first processes the insulation layer with a dense micro-column structure at the head end by the indenter, and then forms the straight-section insulation layer by the vulcanization process, thereby solving the problem of forming the insulation layer with a dense micro-column structure.

[0105] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An adiabatic layer forming device for a dense micro-column structure, characterized in that, Comprising: A base, which is provided with a cavity for carrying the combustion chamber housing; A mandrel, vertically arranged inside the combustion chamber housing, and the mandrel is coaxial with the combustion chamber housing; An upper mold, including a press head for pressing the raw material of the insulation layer into the head end of the combustion chamber housing, and blind holes for forming a plurality of columnar structures are arranged at the press head; Wherein, the upper mold is provided with a through hole for the mandrel to penetrate. When the upper mold is pressed into the combustion chamber housing, the mandrel is simultaneously inserted into the through hole to position the upper mold.

2. The adiabatic layer forming device for the dense micro-column structure according to claim 1, characterized in that The shape inside the cavity matches the combustion chamber housing; wherein, when the raw material of the insulation layer is pressed into the head end of the combustion chamber housing, the combustion chamber housing serves as the lower mold.

3. The insulating layer forming device for the dense micro-column structure according to claim 1, characterized in that, A gas storage cavity is arranged inside each of the blind holes; wherein, each blind hole is communicated with the corresponding inner side gas storage cavity through an exhaust hole.

4. The adiabatic layer forming device for the dense micro-column structure according to claim 1, characterized in that, The blind hole of each columnar structure is a conical structure or a cylindrical structure.

5. Application of the device according to any one of claims 1 to 4 in the forming of a dense micro-columnar structure insulation layer.

6. A forming method for an insulating layer of a dense micro-column structure, characterized in that, Using the device for forming a dense micro-columnar structure insulation layer according to claim 1 or 2, comprising: Transfer the mandrel into the combustion chamber housing, and then integrally install it into the base; Cut the ethylene propylene diene monomer rubber into circular rings and strips; Install the circular ring ethylene propylene diene monomer rubber into the combustion chamber housing, and fill the blind holes of the press head of the upper mold with the strip ethylene propylene diene monomer rubber; After installing the upper mold into the combustion chamber housing, place the whole in a vulcanizer, preheat at 80 - 95 °C for 3 - 6 min, then adjust the pressure of the vulcanizer to close the mold. After exhausting air multiple times, close the mold and hold the pressure, and keep the temperature at 150 - 165 °C for 65 - 75 min, then cool down to 55 - 65 °C to remove the mold, and thus a dense micro-columnar structure insulation layer is obtained at the head end of the combustion chamber housing.

7. The method for forming the heat insulation layer of the dense micro-column structure according to claim 6, characterized in that, Before pressing the film at the head end of the combustion chamber housing, an adhesive is also applied to the die-pressing part at the head end of the combustion chamber housing and left to dry at room temperature for 1 - 2 h.

8. The method for forming the heat-insulating layer of the dense micro-column structure according to claim 6, characterized in that It also includes the forming of the straight-section insulation layer inside the combustion chamber housing, and its forming method includes: Using a mold to press multiple straight-section insulation layers; Paste the straight-section insulation layers on the inner wall of the straight section inside the combustion chamber housing; After transferring the front plug cover into the combustion chamber housing, sequentially install the support plate, silica gel ring, and airbag close to the head end, and then install the rear plug cover of the combustion chamber housing; then, place the whole in an oven, inflate the airbag, and raise the temperature of the oven to 150 - 165 °C, and keep the temperature for 65 - 75 min to obtain the straight-section insulation layer inside the combustion chamber housing.

9. The method for forming the heat-insulating layer of the dense micro-column structure according to claim 8, wherein, During the forming process of the insulation layer, adjacent straight-section insulation layers are overlapped through inclined chamfers; each straight-section insulation layer is overlapped with the flash of the head-end insulation layer.

10. The method for forming the heat insulation layer of the dense micro-column structure according to claim 8, characterized in that, The support plate is used to isolate the dense micro-columnar structure insulation layer at the head end to prevent the influence on the dense micro-columnar structure insulation layer when the airbag is pressurized.

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