Molds and processing methods for forming large fairings

Abstract

This invention provides a mold and processing method for forming large fairings. The mold includes a main mold with multiple support points on its outer bottom, a transfer support plate on its outer bottom, and lifting rods on its outer periphery. A surrounding strip is fixed to the inner wall of the main mold along the outer contour of the product. A window core mold is securely installed on the inner wall of the main mold, and a silicone rubber ring is fitted onto the window core mold. Multiple air nozzles are evenly distributed around the periphery of the main mold. A demolding insert is installed on the demolding side of the main mold in the flight direction. The demolding assembly and the demolding insert are detachably connected, and the demolding assembly demolds the product along the flight direction. Through the cooperation of the demolding assembly and the demolding insert, the product is demolded along the flight direction, avoiding damage to the product caused by the uncontrollable demolding force of the overhead crane during vertical lifting. Furthermore, the window core mold is made of aluminum alloy, which facilitates both the separation of the window core mold from the main mold along with the product and the separation of the window core mold from the product during the demolding stage, thus improving the success rate of demolding.

Description

Technical Field

[0001] This invention relates to the field of mold design technology, and more specifically, to a mold and processing method for forming large fairings. Background Technology

[0002] The launch vehicle fairing is a crucial component of the launch vehicle, protecting the satellite from harmful environmental factors such as aerodynamic forces, aerodynamic heating, and acoustic vibrations. Traditional rocket fairings are made of aluminum alloy or fiberglass skin with an aluminum alloy frame. This type of fairing is not only heavy but also lacks wave-transmitting capabilities, requiring different wave-transmitting windows to be created for different satellites, which brings inconvenience to model development.

[0003] Therefore, the fairing currently adopts a honeycomb sandwich structure, in which the inner and outer panels are made of glass fiber cloth reinforced composite material, and the space between the inner and outer panels is filled with aramid paper honeycomb. In order to reduce mold costs, improve product surface accuracy, and shorten the development cycle, fairings with this structure usually adopt the method of co-curing the skin and honeycomb as a whole.

[0004] Large rocket fairings consist of a cylindrical section, a von Kármán section, and a bulbous nose section. Currently, they are developed using a method where each of the three parts is molded separately and then assembled as a whole. However, this method still requires multiple sets of molds, resulting in long development costs and a long development cycle. Furthermore, the assembly of the three parts affects the overall precision of the fairing. Therefore, a new type of fairing has emerged, where the cylindrical section, von Kármán section, and bulbous nose section are molded as a single unit. This integrally molded fairing requires only one molding mold and eliminates the need for assembly, significantly reducing development costs and time. The overall precision of the fairing is also improved due to the integral molding process.

[0005] A Chinese patent application with publication number CN112123813A discloses a co-curing molding tooling for a large-size arc-shaped variable rectangular cross-section honeycomb sandwich structure. The upper mold, lower mold, and lower mold side block are connected and assembled by positioning pins. The upper mold, lower mold, and lower mold side block together form a molding female mold. In the molding female mold, the upper mold and lower mold, the lower mold and lower mold side block, and the upper mold and lower mold side block are further sealed by sealing grooves. The upper mold, lower mold, and lower mold side block are all made of cast iron.

[0006] The fairing molds in the existing technology have the following defects:

[0007] 1. The mold is very large in size and weight, which will make it extremely inconvenient to transport the mold, the heat capacity of the mold is too large and the temperature rises slowly, the overall temperature field distribution of the mold is uneven, and the mold surface profile is easily affected by the site.

[0008] 2. Because the overall cover has an open structure, if the product is demolded vertically as usual, the lateral force generated by the lifting equipment will cause the product to tend to close up. Furthermore, the overhead crane will generate uncontrollable demolding force, further increasing the risk of product damage during demolding.

[0009] 3. The large overall surface area of ​​the cover means that friction, sticking force, and local air trapping during the demolding process will significantly increase the final demolding force of the product. Since the product has no pre-reserved demolding force points, if conventional methods are used to drill lifting holes at the product blank allowance, the lifting hole positions may be damaged because they cannot withstand the excessive demolding shear force, ultimately leading to demolding failure. Summary of the Invention

[0010] In view of the deficiencies in the prior art, the purpose of this invention is to provide a mold and processing method for forming large fairings.

[0011] According to the present invention, a mold for forming a large fairing includes a main mold, a surrounding strip, air nozzles, a window core mold, a silicone rubber ring, a demolding insert, and a demolding assembly. The main mold has multiple support points on its outer bottom and a transfer support plate on its outer bottom. A lifting rod is provided on the outer periphery of the main mold. The surrounding strip is fixed to the inner wall of the main mold along the outer contour of the product. The window core mold is securely installed on the inner wall of the main mold. The silicone rubber ring is sleeved on the window core mold. Multiple air nozzles are evenly distributed around the periphery of the main mold. The demolding insert is installed on the flight demolding side of the main mold and is cured together with the product. The demolding assembly is detachably connected to the demolding insert, and the demolding assembly demolds the product along the flight direction.

[0012] Preferably, the main mold includes a cylindrical section, a von Kármán section, and a ball head section arranged sequentially; the main mold includes a mold panel and a frame structure, the inner surface of the mold panel forms the inner wall of the main mold, and the frame structure is connected to the outer surface of the mold panel.

[0013] Preferably, the support point, the transfer support plate, and the hoisting rod are all set on the frame structure, and the rib density of the frame structure at the positions of the support point, the transfer support plate, and the hoisting rod is increased and the thickness is increased.

[0014] Preferably, ventilation holes are provided on the stiffening plates of the frame structure, and target holes are provided around the main mold.

[0015] Preferably, the support points are symmetrically arranged on the main mold with respect to the center of gravity of the main mold, and at least three support points are provided at the bottom of the main mold; the lifting rods are symmetrically arranged on the main mold with respect to the center of gravity of the main mold.

[0016] Preferably, the surrounding strip forms a space for installing a demolding insert on the demolding side of the main mold, and the demolding insert has a transition chamfer on the side closer to the product.

[0017] Preferably, the demolding assembly includes a screw, a support plate, and a nut, wherein the screw is threaded through the support plate, and the nut is threadedly fitted onto one end of the screw.

[0018] Preferably, the material of the window core mold includes aluminum alloy.

[0019] Preferably, the demolding direction is the axial direction of the main mold.

[0020] According to the present invention, a processing method for a mold for forming a large fairing includes the following steps: S1, fixing the surrounding strip along the outer contour of the product to the inner wall of the main mold, and forming a space for installing the demolding insert on the flight side of the main mold; S2, placing the aramid paper honeycomb on the inner surface of the main mold and curing it, and then demolding the paper honeycomb and cutting out its shape by machining; S3, installing the demolding insert, evenly distributing the air nozzles around the main mold, fixing the window core mold on the main mold, and fitting the silicone rubber ring onto the window core mold; S4, performing a layering operation on the main mold with reference to laser projection and laying angle lines, first laying the outer skin, then placing the cured aramid paper honeycomb, and finally laying the inner skin; S5, making a bag on the mold and curing it; S6, after curing, removing the fixing parts, connecting the demolding assembly to the demolding insert, and pulling the demolding insert for flight demolding.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention achieves product demolding in the direction of travel by using demolding components and demolding inserts in combination, avoiding damage to the product caused by the uncontrollable demolding force of the crane during vertical lifting. In addition, the window core mold material is aluminum alloy, which is conducive to the separation of the window core mold from the main mold along with the product during the demolding stage, and also facilitates the separation of the window core mold from the product, thus helping to improve the success rate of demolding.

[0023] 2. The present invention, by opening ventilation holes in the main mold rib plate, can not only reduce weight, but also allow the high-temperature airflow in the autoclave to pass through the ventilation holes and heat the mold quickly and evenly, thereby making the temperature field of the mold uniformly distributed and avoiding thermal stress caused by uneven temperature distribution in the product.

[0024] 3. The present invention uses a welded structure for the main mold and a thin and uniform thickness for the mold panel, which results in a small heat capacity and a fast heating rate.

[0025] 4. By arranging three support points at the bottom of the main mold, the present invention ensures that the stress points of the mold remain consistent regardless of the site conditions, thereby guaranteeing that the mold surface profile remains consistent in different locations.

[0026] 5. By symmetrically arranging the support points and lifting rods of the main mold relative to the center of gravity of the mold, this invention can ensure that the mold remains balanced during transportation and hoisting, and avoid safety accidents caused by mold tilting during hoisting.

[0027] 6. The present invention provides a stable demolding point by using a demolding embedding part that is co-cured with the product.

[0028] 7. This invention improves bag-making efficiency by connecting the air nozzle and the main mold into one unit. Attached Figure Description

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram illustrating the overall structure of the main mold of this invention;

[0031] Figure 2 This is a schematic diagram illustrating the bottom structure of the main mold of this invention;

[0032] Figure 3 This is a schematic diagram illustrating the periphery of the main frame structure of the present invention;

[0033] Figure 4 This is a schematic diagram illustrating the overall structure of the demolding assembly, which is the main feature of this invention.

[0034] Figure 5 This is a schematic diagram illustrating the overall structure of the demolding embedded part, which is the main feature of this invention.

[0035] Figure 6 This is a schematic diagram illustrating the main structure of the silicone rubber ring installation in this invention.

[0036] As shown in the figure:

[0037] Main mold 1, window core mold 4

[0038] Support point 11, silicone rubber ring 5

[0039] 12 lifting rods and 6 demolding embedded parts

[0040] 13 Transfer support plate, 7 demolding components

[0041] Target hole 14, support plate 71

[0042] Ventilation hole 15, screw 72

[0043] 2 strips, 73 nuts

[0044] Valve 3 Detailed Implementation

[0045] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0046] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 as well as Figure 6 As shown, a mold for forming a large fairing according to the present invention includes a main mold 1, a retaining strip 2, an air nozzle 3, a window core mold 4, a silicone rubber ring 5, a demolding insert 6, and a demolding assembly 7. The main mold 1 has multiple support points 11 on its outer bottom, and a transfer support plate 13 is also provided on its outer bottom. Lifting rods 12 are provided on the outer periphery of the main mold 1. The retaining strip 2 is fixed to the inner wall of the main mold 1 along the outer contour of the product. The window core mold 4 is securely installed on the inner wall of the main mold 1. The silicone rubber ring 5 is sleeved on the window core mold 4. Multiple air nozzles 3 are evenly distributed around the periphery of the main mold 1. The demolding insert 6 is installed on the flight demolding side of the main mold 1, and the demolding insert 6 is cured together with the product. The demolding assembly 7 is detachably connected to the demolding insert 6, and the demolding assembly 7 demolds the product along the flight direction.

[0047] Specifically, the main mold 1 includes a cylindrical section, a von Kármán section, and a ball-head section arranged sequentially. The main mold 1 includes a mold panel and a frame structure. The inner surface of the mold panel forms the inner wall of the main mold 1, and the frame structure is connected to the outer surface of the mold panel. The frame structure is formed by the cooperation of horizontal stiffeners, vertical stiffeners, diagonal stiffeners, and reinforcing stiffeners. Furthermore, the support point 11, the transfer support plate 13, and the lifting rod 12 are all set on the frame structure, and the stiffener density and thickness of the frame structure at the positions of the support point 11, the transfer support plate 13, and the lifting rod 12 are increased.

[0048] The main mold 1 is an integral welded structure. The mold panel is made of steel plate with a thickness of 15mm, and the stiffening plate is 10mm thick. Ventilation holes 15 are provided on the stiffening plate of the frame structure, and target holes 14 are provided around the main mold 1. Due to the thin and uniform thickness of the mold panel, the mold has a small heat capacity and a fast heating rate. The ventilation holes 15 on the stiffening plate not only reduce weight but also allow the high-temperature airflow in the autoclave to pass through the ventilation holes 15, quickly and evenly heating the mold. This ensures a uniform temperature distribution throughout the mold and prevents thermal stress in the product caused by uneven temperature distribution.

[0049] Furthermore, the support points 11 are symmetrically arranged on the main mold 1 with respect to the center of gravity of the main mold 1, and at least three support points 11 are provided at the bottom of the main mold 1. The lifting rods 12 are symmetrically arranged on the main mold 1 with respect to the center of gravity of the main mold 1.

[0050] One feasible implementation of this application is as follows: three support points 11 are welded to the bottom of the main mold 1, and four lifting rods 12 are welded to the side of the main mold 1. The mold can be transferred by lifting the lifting rods 12, or by using a forklift to support the transfer support plate 13, or by using a ground-supported tank at the bottom of the transfer support plate 13. Target holes 14 are evenly distributed along the product contour of the main mold 1 for placing targets by laser projection later. Product lines and layup angle lines are engraved on the surface of the main mold 1.

[0051] The three support points 11 arranged at the bottom of the main mold ensure that the stress points of the mold remain consistent regardless of the site conditions, thus guaranteeing that the profile of the main mold 1 remains consistent in different locations. The symmetrical arrangement of the support points 11 and the lifting rod relative to the center of gravity of the main mold 1 ensures that the main mold 1 remains balanced during transportation and hoisting, preventing safety accidents caused by tilting of the main mold 1 during hoisting.

[0052] The retaining strip 2 is fixed to the main mold 1 along the outer contour of the product, and the retaining strip 2 has an overflow groove. The retaining strip 2 forms a space for installing the demolding insert 6 on the ejection side of the main mold 1. The demolding insert 6 has a transition chamfer on the side near the product to prevent bridging of the product layers and ensure product compaction. The demolding insert 6 has a threaded hole on the side away from the product for detachable connection to the demolding assembly 7. Two demolding inserts 6 are symmetrically arranged on the ejection side of the main mold 1 about the central axis of the main mold 1. The material of the window core mold 4 includes aluminum alloy. The demolding direction is the axial direction of the main mold 1, and the product can be demolded along the direction of demolding to avoid product shrinkage deformation caused by demolding in the vertical direction.

[0053] Preferably, the main mold 1, the retaining strip 2, the air nozzle 3, and the demolding insert 6 are all made of Q235 aluminum alloy, while the window core mold 4 is made of 2A12 aluminum alloy. Because aluminum alloy has a lower density and a larger coefficient of linear expansion, it facilitates both the separation of the window core mold 4 from the main mold 1 along with the product and the separation of the window core mold 4 from the product during the demolding stage. The air nozzle 3 is integrated with the main mold 1, which improves bag-making efficiency.

[0054] The demolding assembly 7 includes a screw 72, a support plate 71, and a nut 73. The screw 72 is threaded through the support plate 71, and the nut 73 is threadedly installed at one end of the screw 72.

[0055] According to the present invention, a processing method for forming a large fairing includes the following steps:

[0056] S1. Fix the outer strip 2 along the outer contour of the product to the inner wall of the main mold 1, and form a space for installing the demolding insert 6 on the demolding side of the main mold 1.

[0057] S2. Place the aramid paper honeycomb on the inner surface of the main mold 1 and solidify it. After the paper honeycomb is demolded, it is cut out into shape by machining.

[0058] S3. Install the demolding insert 6, and evenly distribute the air nozzles 3 around the main mold 1. Fix the window core mold 4 on the main mold 1, and fit the silicone rubber ring 5 onto the window core mold 4. The window core mold 4 is positioned by pins and fastened to the designated position on the main mold 1 with screws. The designated position is the window position of the product. The silicone rubber ring 5 provides lateral pressure to the window position of the product during the product curing process.

[0059] S4. Referring to the laser projection and the laid-out angle lines, perform the layering operation on the main body mold 1. First, lay the outer skin, then place the cured and shaped aramid paper honeycomb, and finally lay the inner skin. Specifically, after all parts are installed, refer to the laser projection and the laid-out angle lines to perform the layering operation on the main body mold 1. First, lay the outer skin, then place the cured and shaped aramid paper honeycomb, and finally lay the inner skin. During the process, the demolding embedding part 6 is laid and wrapped around the remaining space of the product blank.

[0060] S5. Make bags on the mold and cure them. Specifically, after the layers are laid, make bags on the mold. The breathable felt should cover the three holes of the air nozzle, and the sealing strip should be attached to the outside of the three holes of the air nozzle. Then, pressurize and cure the bags in an autoclave.

[0061] S6. After curing, remove the fixing parts, connect the demolding assembly 7 to the demolding insert 6, and pull the demolding insert 6 to demold in the flight direction. After curing, remove all pins, screws and silicone rubber bushings, connect the demolding assembly 7 to the demolding insert 6, manually tighten the nut 73 in the demolding assembly 7 so that the screw 72 connects with the threaded hole of the demolding insert 6, and then pull the demolding insert 6 to move in the flight direction. The window core mold 4 demolds along the flight direction with the product. After the product separates from the main mold 1, the window core mold 4 is then removed from the product.

[0062] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0063] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A mold for forming a large fairing, characterized by, The mold comprises a main body mold (1), a surrounding strip (2), an air nozzle (3), a window core mold (4), a silicone rubber ring (5), a demolding embedded part (6) and a demolding assembly (7); The outer bottom of the main body mold (1) is provided with a plurality of support points (11), and the outer bottom of the main body mold (1) is also provided with a transfer support plate (13); the outer periphery of the main body mold (1) is provided with a lifting rod (12). The surrounding strip (2) is fixed on the inner wall of the main body mold (1) along the product outer contour, the window core mold (4) is tightly installed on the inner wall of the main body mold (1), the silicone rubber ring (5) is sleeved on the window core mold (4), and the air nozzle (3) is uniformly distributed on the periphery of the main body mold (1). The demolding embedded part (6) is installed on the demolding side of the main body mold (1) in the heading direction, and the demolding embedded part (6) is solidified with the product; the demolding assembly (7) is detachably connected with the demolding embedded part (6), and the demolding assembly (7) demolds the product in the heading direction, and the heading direction is the axial direction of the main body mold (1). The surrounding strip (2) forms a space for installing the demolding embedded part (6) on the demolding side of the main body mold (1) in the heading direction, and the side close to the product of the demolding embedded part (6) is provided with a transition chamfer. The demolding assembly (7) comprises a screw rod (72), a support plate (71) and a nut (73), the screw rod (72) is threaded through the support plate (71), and the nut (73) is threadedly and fitly installed on one end of the screw rod (72).

2. The mold for forming a large fairing according to claim 1, wherein The main body mold (1) comprises a cylinder segment, a von Karman segment and a ball head segment arranged in sequence. The main body mold (1) comprises a profiled panel and a frame structure, an inner surface of the profiled panel forms an inner wall of the main body mold (1), and the frame structure is connected to an outer surface of the profiled panel.

3. The mold for forming a large fairing according to claim 2, wherein The support points (11), the transfer support plate (13) and the lifting rod (12) are all arranged on the frame structure, and the rib plate density and thickness of the frame structure at the positions of the support points (11), the transfer support plate (13) and the lifting rod (12) are increased.

4. The mold for forming a large fairing according to claim 2, wherein Ventilation holes (15) are formed in the rib plate of the frame structure, and target holes (14) are formed around the main body mold (1).

5. The mold for forming a large fairing according to claim 1, wherein The support points (11) are symmetrically arranged on the main body mold (1) with the center of gravity of the main body mold (1) as the center, and at least three support points (11) are arranged on the bottom of the main body mold (1). The lifting rod (12) is symmetrically arranged on the main body mold (1) with the center of gravity of the main body mold (1) as the center.

6. The mold for forming a large fairing according to claim 1, wherein The material of the window core mold (4) comprises an aluminum alloy.

7. A method for processing large fairings, characterized in that, The mold for forming a large fairing according to any one of claims 1-6 is used in a processing method comprising the following steps: S1, fixing the surrounding strip (2) on the inner wall of the main body mold (1) along the product outer contour, and forming a space for installing the demolding embedded part (6) on the demolding side of the main body mold (1) in the heading direction; S2, placing the aramid paper honeycomb on the inner surface of the main body mold (1) for curing and shaping, and cutting the shape of the shaped paper honeycomb after demolding by machining. S3, install the demolding insert (6), install the air nozzle (3) evenly around the main mold (1), fix the window core mold (4) on the main mold (1), and put the silicone rubber ring (5) on the window core mold (4); S4, refer to the laser projection and the angle line to lay the layer on the main mold (1), first lay the outer skin, then place the cured and shaped aramid paper honeycomb, and finally lay the inner skin; S5, bag making on the mold and curing; S6, after the curing is completed, remove the fixing part, connect the demolding assembly (7) with the demolding insert (6), and pull the demolding insert (6) to demold in the heading direction.

Images