Preparation method and forming die of aerospace probe olive ball-shaped heat shield layer

Abstract

The application relates to a preparation method and a forming die of a space probe rugby-shaped heat-proof layer, which adopts an optimized prepared quartz fiber preform as a reinforcing body, adopts nano-porous hybrid phenolic resin as a base body, adopts a set of forming dies to prepare upper, middle and lower parts of the rugby-shaped heat-proof layer, and obtains the rugby-shaped heat-proof layer through mechanical processing and assembly of the heat-proof layer parts. Compared with the prior art, the preform is prepared through a plurality of modes such as needling, wire winding and sewing, so that the structural strength of the heat-proof layer and the strength of the connecting part are effectively ensured, the low density and the heat-proof and heat-insulating performance of the heat-proof layer are ensured, the forming die of the application is optimized and designed, the three parts of the heat-proof layer can be formed through a set of the die, the forming period is shortened, the manufacturing cost is reduced, and the consistency of the heat-proof layer quality is ensured.

Description

Technical Field

[0001] This invention relates to the field of aerospace heat-resistant composite material preparation technology, and in particular to a method for preparing a rugby ball-shaped heat-resistant layer for a space probe and a molding die. Background Technology

[0002] The heat shield of a spacecraft is a crucial component of the load-bearing outer shell of the spacecraft's return capsule, its primary function being to dissipate or block aerodynamic heat. During space exploration, the heat shield plays a vital role, protecting the spacecraft from high-temperature damage as it traverses the atmosphere. In materials science, the heat shield of spacecraft typically employs materials with high thermal resistance, high-temperature resistance, and ablation resistance. These materials undergo special processing to maintain stable performance in the high-temperature environment of the atmosphere.

[0003] With the continuous development of aerospace technology, the requirements for the performance of heat shields are also constantly increasing. Research and application of new heat shield materials, advanced manufacturing processes, and intelligent thermal protection systems will all support the technological advancement of heat shields for aerospace probes. In recent years, the technology of heat shields for new probes has been continuously updated, placing higher demands on the material properties and molding technology of heat shields. This requires heat shield materials to have excellent mechanical and thermophysical properties, molding processes to have good stability, and the heat shield to be customizable to adapt to changes in the probe's structural form.

[0004] In summary, the heat shield of a spacecraft is a crucial component, and its performance directly impacts the spacecraft's flight safety and mission success. Therefore, in-depth research and continuous improvement of this layer are of great significance for advancing space technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing an olive-shaped heat-resistant layer for a space probe and a molding die.

[0006] The objective of this invention can be achieved through the following technical solution: a method for preparing a rugby ball-shaped heat shield for a space probe, comprising the following steps: S1 Preform Preparation: Quartz fiber preforms are prepared by laminating quartz fiber mesh and quartz fiber cloth. A combination of one layer of quartz fiber mesh and one layer of quartz fiber cloth constitutes a unit. After completing the needle-punched structure of one unit preform, quartz fiber filaments are wound around the surface of the quartz fiber mesh. After all fiber needle-punched units are completed, the corresponding positions of the preforms in the corresponding assembly areas of the product are stitched and reinforced. Finally, the quartz fiber mesh is used as the cover to obtain the upper preform, middle preform, and lower preform respectively. S2 heat-insulating layer molding: The upper preform, middle preform, and lower preform are placed into the core mold of the mold according to the mold closing sequence, and the various parts of the mold are assembled and locked. The resin is introduced into the mold using a low vacuum negative pressure method, and the resin is filled into the mold cavity using a gradient pressure method. The rough finished heat-insulating layer is obtained by heating and curing and drying at normal pressure. The excess area of ​​the product is removed by mechanical processing to obtain the upper, middle, and lower parts of the heat-insulating layer. S3 heat shield surface treatment and assembly: A waterproof coating is sprayed onto the outer surface of the heat shield (including the upper, middle and lower parts of the heat shield). After the waterproof coating dries at room temperature and is cured by heating, the upper, middle and lower parts of the heat shield are assembled to obtain a rugby ball-shaped heat shield for a space probe.

[0007] This invention achieves low-cost and high-efficiency preparation of the heat-resistant layer through optimized design. By optimizing the mold design, the three parts of the heat-resistant layer are formed in one mold, which fully ensures the consistency of quality of the three parts of the heat-resistant layer.

[0008] Preferably, the areal density of the quartz fiber mesh in step S1 is 45 g / cm³. 2 -60g / cm 2 The surface density of the quartz fiber fabric is 150 g / cm³. 2 -300g / cm 2 The needle density of the quartz fiber preform is 15-30 needles / cm. 2 .

[0009] Preferably, the suture reinforcement method in step S1 is cross suture, with a suture spacing of 2-5 mm.

[0010] Preferably, the number of layers of the quartz fiber mesh cover in step S1 is 1-3.

[0011] Preferably, in step S1, the preform is prepared using conformal tooling to form an upper preform and a lower preform with a spherical structure, as well as a middle preform with a cylindrical structure.

[0012] Preferably, in step S1, the thickness of the needle-punched structure of a single preform is 0.7-1 mm.

[0013] Preferably, the maximum thickness of the upper precast body, the middle precast body, and the lower precast body is 25-35 mm, and the minimum thickness is 12-18 mm.

[0014] Preferably, the vacuum negative pressure value of the low vacuum negative pressure in step S2 is 300mbar-600mbar.

[0015] Preferably, the resin in step S2 comprises a nanoporous hybrid phenolic resin. The nanoporous hybrid phenolic resin undergoes surface ceramization at high temperatures, which provides an anti-erosion effect.

[0016] Preferably, the maximum pressure of the gradient pressurization in step S2 is 0.6 MPa, and the pressurization range for each pressurization step is 0.04~0.06 MPa.

[0017] Preferably, the heating and curing in step S2 adopts a gradient heating method, first heating at 90-100℃ for 20-30 hours, and then heating at 120-130℃ for 10-14 hours.

[0018] Preferably, the atmospheric pressure drying in step S2 adopts a gradient temperature increase, first heating at 85-95℃ for 20-30 hours, and then heating at 115-125℃ for 10-14 hours.

[0019] Preferably, the amount of waterproof coating applied in step S3 is 0.3-0.8 g / cm³. 2 .

[0020] Preferably, the waterproof coating in step S3 is an RLHY-12 series high-temperature resistant heat insulation coating.

[0021] Preferably, the room temperature drying time in step S3 is 2-3 hours.

[0022] Preferably, the curing temperature in step S3 is 45-55℃, and the time is 5-6 hours.

[0023] Preferably, in step S2, threaded holes are machined in the corresponding assembly areas of the upper, middle, and lower parts of the heat-insulating layer, and in step S3, locking bolts are used to assemble the upper, middle, and lower parts of the heat-insulating layer.

[0024] A molding die for the preparation method of the rugby ball-shaped heat shield layer of the aforementioned space probe includes a core mold, an upper mold block, a lower mold block, a left mold block, a right mold block, a left retaining ring, and a right retaining ring.

[0025] Preferably, the upper mold block, left mold block, and right mold block are provided with injection ports and dispensing ports.

[0026] Preferably, the left and right retaining rings are provided with glue injection channels.

[0027] More preferably, the glue injection channel is an annular glue injection channel.

[0028] Preferably, the left and right retaining rings are provided with glue injection holes.

[0029] Preferably, the molding die is connected to the glue injection system.

[0030] More preferably, the glue injection system includes a glue injection pipeline, a glue outlet pipeline, and a ball valve installed on the pipeline.

[0031] Preferably, the molding die is provided with a positioning guide structure.

[0032] More preferably, the positioning and guiding structure is achieved by using the bosses on the left and right mold blocks and the grooves on the upper and lower mold blocks for positioning.

[0033] More preferably, the positioning guide structure includes bosses disposed on opposite sides of the left mold block and the right mold block, and grooves disposed on the upper mold block and the lower mold block corresponding to the bosses.

[0034] Preferably, the left retaining ring and the right retaining ring are located at both ends of the core mold body, and the upper mold block, lower mold block, left mold block and right mold block are located at the top, bottom, left and right sides of the core mold, respectively.

[0035] Preferably, the left retaining ring and the right retaining ring serve as positioning references for the upper mold block and the lower mold block.

[0036] More preferably, the left retaining ring includes an upper left retaining ring located on the upper side of the core mold body and a lower left retaining ring located on the lower side of the core mold body.

[0037] More preferably, the right retaining ring includes an upper right retaining ring located on the upper side of the core mold body and a lower right retaining ring located on the lower side of the core mold body.

[0038] Preferably, the molding die further includes a support, and the lower mold block is placed on the support.

[0039] Preferably, the molding die further includes a sealing structure and a locking structure.

[0040] More preferably, the sealing structure includes a sealing ring for preventing air leakage from the mold.

[0041] More preferably, the locking structure includes bolts for connecting the various modules of the mold.

[0042] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides an effective heat-resistant layer molding solution, which solves the detector's requirements for heat protection, heat insulation, erosion resistance, and mechanical properties of the heat-resistant layer; 2. This invention provides an innovative preparation method, resulting in a lightweight product with significantly improved heat-resistant layer performance; 3. Traditional composite materials are difficult to mold into thick, spherical composite products. This invention achieves high-quality preparation of rugby ball-shaped heat-resistant layers by optimizing the preform molding process and adopting a closed-mold liquid molding scheme. 4. This invention provides a set of heat-resistant layer molding molds, which can mold the three parts of the heat-resistant layer in one mold, effectively improving the molding efficiency of the heat-resistant layer, reducing the molding cost of the heat-resistant layer, and ensuring the performance consistency of the three parts of the product. 5. This invention achieves reliable assembly of the heat-insulating layer by stitching the assembly area; 6. The method provided by this invention can expand the product development ideas of designers and manufacturers of heat-resistant products and promote the development of heat-resistant product manufacturing technology; 7. The rugby ball-shaped detector is used for aerospace military exploration. The rugby ball-shaped heat protection layer of this invention can be applied to the surface of the rugby ball-shaped detector to prevent the heat generated by the detector ball during high-speed operation from damaging the cables and sensing equipment inside the spacecraft. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of the rugby ball-shaped heat shield layer for a space probe according to the present invention; Figure 2 This is an exploded view of the overall structure of the rugby ball-shaped heat shield layer for a space probe according to the present invention; Figure 3 This invention relates to a molding die for a rugby ball-shaped heat shield layer on a spacecraft. Figure 4 This is an anatomical diagram of the molding die for a rugby ball-shaped heat shield layer for a space probe according to the present invention. Figure 5 This is a schematic diagram showing the positions of the injection port and the outlet of the molding die of the present invention; Figure 6 This is a schematic diagram of the injection flow channel of the molding die of the present invention; In the diagram: 1-core mold, 2-upper mold block, 3-lower mold block, 4-left mold block, 5-right mold block, 6-left retaining ring, 61-left upper retaining ring, 62-left lower retaining ring, 7-right retaining ring, 71-right upper retaining ring, 72-right lower retaining ring, 8-bracket, 9-injection port, 10-outlet port, 11-injection channel; 01 - Upper part of heat protection layer, 02 - Middle part of heat protection layer, 03 - Lower part of heat protection layer, 04 - Locking bolt. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0046] Example 1 A method for fabricating a rugby ball-shaped heat shield for a space probe, wherein the rugby ball-shaped heat shield has the following properties: Figures 1-2 The structure shown includes an upper heat-insulating layer 01, a middle heat-insulating layer 02, a lower heat-insulating layer 03, and a locking bolt 04 for assembling the three components. It utilizes a structure having, for example... Figures 3-6 The molding die for the structure shown is made by the following steps: Step 1: Preform Preparation Using 45g / cm 2 Quartz fiber mesh with a surface density of 200 g / cm³ 2 Quartz fiber preforms are prepared by laminating layers of quartz fiber cloth with varying surface density. Each unit consists of a layer of quartz fiber mesh and a layer of quartz fiber cloth. Thicker areas are achieved by locally adding more units. The needle-punching density of the fiber preform is 30 needles / cm². 2 After completing the needle-punched structure of one prefabricated unit, 195tex fiber filaments are used to reinforce the prefabricated unit with a winding distance of 5mm. Once all fiber-punched and winding units are completed, local cross-stitch reinforcement is performed at the corresponding positions on the prefabricated units in the product's assembly area, with a stitch spacing of 5mm. Then, three layers of 45 g / cm³ fiber are used for reinforcement. 2 The surface density of the quartz fiber mesh is used as the cover.

[0047] Step 2: Forming the heat-insulating layer Assemble the left lower retaining ring 62 and the right lower retaining ring 72 onto the lower mold block 3. Hoist the core mold 1 vertically, and slowly slide the preformed middle section of the heat-insulating layer onto the core mold 1 from the bottom. Adjust the hoisting position of the core mold 1 to place it horizontally. Slide the upper and lower parts of the heat-insulating layer onto the core mold 1, and place them together onto the lower mold block 3. Position the left upper retaining ring 61 and the right upper retaining ring 71 onto the left lower retaining ring 62 and the right lower retaining ring 72 using pins. Position the upper mold block 2 onto the lower mold block 3 and initially tighten it with bolts. Position and lock the left mold block 4 and the right mold block 5 onto the upper mold block 2 and the lower mold block 3, and further tighten the upper mold block 2 and the lower mold block 3 with bolts. Install the ball valve and components, and connect the injection pipe and the dispensing pipe.

[0048] Adjust the vacuum negative pressure reading to 300 mbar, open the ball valve at the injection port, and the product begins injection. The silicon-boron hybrid phenolic resin enters the mold through injection port 9, and then flows through the injection holes on the left upper retaining ring 61 and right upper retaining ring 71 into the injection channels 11 on both sides of the left upper retaining ring 61, right upper retaining ring 71, left lower retaining ring 62, and right lower retaining ring 72. The resin is injected into the end face of the heat-insulating layer preform through the injection channels 11, wetting the heat-insulating layer preform. When the resin flow rate is less than 60 g / min, start the pressure injection mode, adjusting the injection pressure by 0.05 MPa each time. When all the resin has exited from the mold outlet 10, remove any bubbles from the resin. Once bubble removal is complete, end the injection process and disassemble the injection system. The maximum pressure during the injection process must not exceed 0.6 MPa.

[0049] The mold is transported to the heating equipment and heated at 95℃ for 24 hours, then increased to 125℃ for 12 hours to fully cure the resin. The mold is then cooled to room temperature with the furnace. The rough finished products of the upper, middle, and lower heat-insulating layers are removed from the mold and placed on a drying fixture for drying at 90℃ for 24 hours, then increased to 120℃ for 12 hours. The dried heat-insulating layer is then rough-machined using a milling machine. When the remaining 2-3mm is left, it is fine-ground using a grinding machine. The threaded holes on the heat-insulating layer are made using a thread milling cutter. Finally, the finished parts of the upper, middle, and lower heat-insulating layers are obtained.

[0050] Step 3: Surface treatment and assembly of the heat-insulating layer: Place the heat-insulating layer in a clean room and spray RLHY-12 coating. The distance between the spray gun and the product should be 15-20mm. The application rate of the waterproof coating is 0.6g / cm². 2 The waterproof coating needs to be dried at room temperature for 2.5 hours, and then placed in a heating device to cure at 50°C for 5.5 hours. Assemble the upper part 01, the middle part 02, and the lower part 03 of the heat-insulating layer, and tighten them with locking bolts 04. Check the gaps in the assembly area; the butt joints in the assembly area must not exceed 0.1 mm.

[0051] The performance of the rugby ball-shaped heat shield for the spacecraft prepared in this embodiment was tested, and its density was measured to be 0.6 g / cm³. 3 The tensile strength is 95 MPa; the thermal conductivity at room temperature is 0.81 W / (m·K); in the oxyacetylene test, after burning at 2000℃ for 30s, the recoil is 0.03 mm, and there is almost no ablation.

[0052] Example 2 A method for preparing a rugby ball-shaped heat shield for a space probe includes the following steps: Step 1: Preform Preparation Using 45g / cm2 Quartz fiber mesh with a surface density of 200 g / cm³ 2 Quartz fiber preforms are prepared by laminating layers of quartz fiber cloth with varying surface density. Each unit consists of a layer of quartz fiber mesh and a layer of quartz fiber cloth. Thicker areas are achieved by locally adding more units. The needle-punching density of the fiber preform is 30 needles / cm². 2 After completing the needle-punched structure of one prefabricated unit, 195tex fiber filaments are used to reinforce the prefabricated unit with a winding distance of 5mm. Once all fiber-punched and winding units are completed, local cross-stitch reinforcement is performed at the corresponding positions on the prefabricated units in the product's assembly area, with a stitch spacing of 5mm. Then, three layers of 45 g / cm³ fiber are used for reinforcement. 2 The surface density of the quartz fiber mesh is used as the cover.

[0053] Step 2: Forming the heat-insulating layer Assemble the left lower retaining ring 62 and the right lower retaining ring 72 onto the lower mold block 3. Hoist the core mold 1 vertically, and slowly slide the preformed middle section of the heat-insulating layer onto the core mold 1 from the bottom. Adjust the hoisting position of the core mold 1 to place it horizontally. Slide the upper and lower parts of the heat-insulating layer onto the core mold 1, and place them together onto the lower mold block 3. Position the left upper retaining ring 61 and the right upper retaining ring 71 onto the left lower retaining ring 62 and the right lower retaining ring 72 using pins. Position the upper mold block 2 onto the lower mold block 3 and initially tighten it with bolts. Position and lock the left mold block 4 and the right mold block 5 onto the upper mold block 2 and the lower mold block 3, and further tighten the upper mold block 2 and the lower mold block 3 with bolts. Install the ball valve and components, and connect the injection pipe and the dispensing pipe.

[0054] Adjust the vacuum negative pressure reading to 300 mbar, open the ball valve at the injection port, and the product begins injection. The silicon-boron hybrid phenolic resin enters the mold through injection port 9, and then flows through the injection holes on the left upper retaining ring 61 and right upper retaining ring 71 into the injection channels 11 on both sides of the left upper retaining ring 61, right upper retaining ring 71, left lower retaining ring 62, and right lower retaining ring 72. The resin is injected into the end face of the heat-insulating layer preform through the injection channels 11, wetting the heat-insulating layer preform. When the resin flow rate is less than 60 g / min, start the pressure injection mode, adjusting the injection pressure by 0.05 MPa each time. When all the resin has exited the mold, remove any bubbles from the resin. Once bubble removal is complete, end the injection process and disassemble the injection system. The maximum pressure during the injection process must not exceed 0.6 MPa.

[0055] The mold is transported to the heating equipment and heated at 95℃ for 24 hours, then increased to 125℃ for 12 hours to fully cure the resin. The mold is then cooled to room temperature with the furnace. The rough finished products of the upper, middle, and lower heat-insulating layers are removed from the mold and placed on a drying fixture for drying at 90℃ for 24 hours, then increased to 120℃ for 12 hours. The dried heat-insulating layer is then rough-machined using a milling machine. When the remaining 2-3mm is left, it is fine-ground using a grinding machine. The threaded holes on the heat-insulating layer are made using a thread milling cutter. Finally, the finished parts of the upper, middle, and lower heat-insulating layers are obtained.

[0056] Step 3: Surface treatment and assembly of the heat-insulating layer: Place the heat-insulating layer in a clean room and spray RLHY-12 coating. The distance between the spray gun and the product should be 15-20mm. The application rate of the waterproof coating is 0.3g / cm². 2 The waterproof coating needs to dry at room temperature for 2 hours, and then be placed in a heating device to cure at 50°C for 6 hours. Assemble the upper, middle and lower parts of the heat-insulating layer and tighten them with locking bolts. Check the gaps in the assembly area; the butt joints in the assembly area should not exceed 0.1 mm.

[0057] Example 3 A method for preparing a rugby ball-shaped heat shield for a space probe includes the following steps: Step 1: Preform Preparation Using 45g / cm 2 Quartz fiber mesh with a surface density of 200 g / cm³ 2 Quartz fiber preforms are prepared by laminating layers of quartz fiber cloth with varying surface density. Each unit consists of a layer of quartz fiber mesh and a layer of quartz fiber cloth. Thicker areas are achieved by locally adding more units. The needle-punching density of the fiber preform is 30 needles / cm². 2 After completing the needle-punched structure of one prefabricated unit, 195tex fiber filaments are used to reinforce the prefabricated unit with a winding distance of 5mm. Once all fiber-punched and winding units are completed, local cross-stitch reinforcement is performed at the corresponding positions on the prefabricated units in the product's assembly area, with a stitch spacing of 5mm. Then, three layers of 45 g / cm³ fiber are used for reinforcement. 2 The surface density of the quartz fiber mesh is used as the cover.

[0058] Step 2: Forming the heat-insulating layer Assemble the left lower retaining ring 62 and the right lower retaining ring 72 onto the lower mold block 3. Hoist the core mold 1 vertically, and slowly slide the preformed middle section of the heat-insulating layer onto the core mold 1 from the bottom. Adjust the hoisting position of the core mold 1 to place it horizontally. Slide the upper and lower parts of the heat-insulating layer onto the core mold 1, and place them together onto the lower mold block 3. Position the left upper retaining ring 61 and the right upper retaining ring 71 onto the left lower retaining ring 62 and the right lower retaining ring 72 using pins. Position the upper mold block 2 onto the lower mold block 3 and initially tighten it with bolts. Position and lock the left mold block 4 and the right mold block 5 onto the upper mold block 2 and the lower mold block 3, and further tighten the upper mold block 2 and the lower mold block 3 with bolts. Install the ball valve and components, and connect the injection pipe and the dispensing pipe.

[0059] Adjust the vacuum negative pressure reading to 300 mbar, open the ball valve at the injection port, and the product begins injection. The silicon-boron hybrid phenolic resin enters the mold through injection port 9, and then flows through the injection holes on the left upper retaining ring 61 and right upper retaining ring 71 into the injection channels 11 on both sides of the left upper retaining ring 61, right upper retaining ring 71, left lower retaining ring 62, and right lower retaining ring 72. The resin is injected into the end face of the heat-insulating layer preform through the injection channels 11, wetting the heat-insulating layer preform. When the resin flow rate is less than 60 g / min, start the pressure injection mode, adjusting the injection pressure by 0.05 MPa each time. When all the resin has exited the mold, remove any bubbles from the resin. Once bubble removal is complete, end the injection process and disassemble the injection system. The maximum pressure during the injection process must not exceed 0.6 MPa.

[0060] The mold is transported to the heating equipment and heated at 95℃ for 24 hours, then increased to 125℃ for 12 hours to fully cure the resin. The mold is then cooled to room temperature with the furnace. The rough finished products of the upper, middle, and lower heat-insulating layers are removed from the mold and placed on a drying fixture for drying at 90℃ for 24 hours, then increased to 120℃ for 12 hours. The dried heat-insulating layer is then rough-machined using a milling machine. When the remaining 2-3mm is left, it is fine-ground using a grinding machine. The threaded holes on the heat-insulating layer are made using a thread milling cutter. Finally, the finished parts of the upper, middle, and lower heat-insulating layers are obtained.

[0061] Step 3: Surface treatment and assembly of the heat-insulating layer: Place the heat-insulating layer in a clean room and spray RLHY-12 coating. The distance between the spray gun and the product should be 15-20mm. The application rate of the waterproof coating is 0.8g / cm². 2The waterproof coating needs to dry at room temperature for 3 hours, and then be placed in a heating device to cure at 50°C for 5 hours. Assemble the upper, middle and lower parts of the heat-insulating layer and tighten them with locking bolts. Check the gaps in the assembly area; the butt joints in the assembly area should not exceed 0.1 mm.

[0062] The fibers, resins, waterproof coatings, and other materials mentioned in the above embodiments can be appropriately selected based on the specific types of these products as raw materials for the preparation method of a rugby ball-shaped heat-resistant layer for a space probe. The molding die of this invention can also be modified to suit the shape of products with different structural forms, serving as molding dies for different products.

[0063] This invention provides a method for preparing a rugby ball-shaped heat-resistant layer for a spacecraft and a molding die. The method uses an optimized quartz fiber preform as reinforcement and nanoporous hybrid phenolic resin as the matrix. A single molding die is used to prepare the upper, middle, and lower parts of the rugby ball-shaped heat-resistant layer. Each part of the heat-resistant layer is obtained through machining and assembly. The preform provided by this invention is prepared using various methods such as needle punching, wire winding, and stitching, effectively ensuring the structural strength and joint strength of the heat-resistant layer, as well as its low density and heat insulation performance. The optimized mold design of this invention allows for the molding of all three parts of the heat-resistant layer using a single die, shortening the molding cycle, reducing manufacturing costs, and ensuring the consistency of the heat-resistant layer's quality.

[0064] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a rugby ball-shaped heat shield for a spacecraft, characterized in that, Includes the following steps: S1 Preform Preparation: Quartz fiber preforms are prepared by laminating quartz fiber mesh and quartz fiber cloth. A combination of one layer of quartz fiber mesh and one layer of quartz fiber cloth constitutes a unit. After completing the needle-punched structure of one unit preform, quartz fiber filaments are wound around the surface of the quartz fiber mesh. After all fiber needle-punched units are completed, the corresponding positions of the preforms in the corresponding assembly areas of the product are stitched and reinforced. Finally, the quartz fiber mesh is used as the cover to obtain the upper preform, middle preform, and lower preform respectively. S2 heat protection layer molding: The upper preform, middle preform and lower preform are placed on the core mold of the mold. After the mold is assembled, the resin is introduced into the mold by low vacuum negative pressure and the resin is filled into the mold cavity by gradient pressure. The rough heat protection layer is obtained by heating curing and normal pressure drying. The excess area is removed to obtain the upper heat protection layer, the middle heat protection layer and the lower heat protection layer. S3 heat protection layer surface treatment and assembly: A waterproof coating is sprayed on the outer surface of the heat protection layer. After the waterproof coating dries at room temperature and is cured by heating, the upper, middle and lower parts of the heat protection layer are assembled to obtain a rugby ball-shaped heat protection layer for a space probe.

2. The method for preparing the rugby ball-shaped heat shield layer for a spacecraft according to claim 1, characterized in that, The areal density of the quartz fiber mesh in step S1 is 45 g / cm³. 2 -60g / cm 2 The surface density of the quartz fiber fabric is 150 g / cm³. 2 -300g / cm 2 The needle density of the quartz fiber preform is 15-30 needles / cm. 2 .

3. The method for preparing the rugby ball-shaped heat shield layer for a spacecraft according to claim 1, characterized in that, The suture reinforcement method described in step S1 is cross suture, with a suture spacing of 2-5 mm; The number of layers of the quartz fiber mesh cover in step S1 is 1-3.

4. The method for preparing the rugby ball-shaped heat shield layer for a spacecraft according to claim 1, characterized in that, The vacuum negative pressure value of the low vacuum negative pressure mentioned in step S2 is 300mbar-600mbar.

5. The method for preparing the rugby ball-shaped heat shield layer for a spacecraft according to claim 1, characterized in that, The maximum pressure of the gradient pressurization in step S2 is 0.6 MPa, and the pressurization range for each pressurization step is 0.04~0.06 MPa.

6. The method for preparing the rugby ball-shaped heat shield layer for a spacecraft according to claim 1, characterized in that, The amount of waterproof coating applied in step S3 is 0.3-0.8 g / cm³. 2 .

7. A molding die used in the preparation method of the rugby ball-shaped heat shield layer of the space probe according to any one of claims 1 to 6, characterized in that, It includes a core mold (1), an upper mold block (2), a lower mold block (3), a left mold block (4), a right mold block (5), a left retaining ring (6), and a right retaining ring (7); The upper mold block (2), left mold block (4), and right mold block (5) are provided with injection ports and dispensing ports; The left retaining ring (6) and the right retaining ring (7) are provided with glue injection channels.

8. The molding die for the method of preparing the rugby ball-shaped heat shield layer of the space probe according to claim 7, characterized in that, The molding die is equipped with a positioning and guiding structure; The positioning guide structure includes bosses on opposite sides of the left mold block (4) and the right mold block (5) and grooves on the upper mold block (2) and the lower mold block (3) corresponding to the bosses.

9. The molding die for the method of preparing the rugby ball-shaped heat shield layer of the space probe according to claim 7, characterized in that, The glue injection channel is an annular glue injection channel.

10. The molding die for the method of preparing the rugby ball-shaped heat shield layer of the space probe according to claim 7, characterized in that, The left retaining ring (6) and the right retaining ring (7) are located at both ends of the core mold (1) body, and the upper mold block (2), lower mold block (3), left mold block (4) and right mold block (5) are located at the top, bottom, left and right sides of the core mold (1).

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