Hollow grid rudder structure of recoverable rocket

Abstract

The invention discloses a hollow grid rudder structure of a recoverable rocket, belongs to the technical field of rocket recovery, and is designed for solving the problems of high processing difficulty and the like of an existing grid rudder formed by tailor welding. The invention discloses a hollow grid rudder structure of a recoverable rocket. The hollow grid rudder structure comprises at least two grid units, wherein each grid unit comprises two ribs arranged in parallel; the two skins are arranged in parallel, and a flat cylindrical structure is defined by the two skins and the two ribs; the bottom flange is connected to an opening in one side of the cylindrical structure defined by the two skins and the two ribs; the at least one rib is located in the barrel-shaped structure defined by the bottom flange, the two skins and the two ribs; and a unit cell; the hollow grid rudder structure is manufactured and formed in a 3D printing mode. The hollow grid rudder structure of the recoverable rocket is manufactured and formed in a 3D printing mode, the weight of the structure can be reduced on the premise that the control and use requirements and the rigidity and strength performance are met, the technology is simple, the machining period is short, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of rocket recovery technology, and more particularly to a hollow grid fin structure for reusable rockets. Background Technology

[0002] The recovery of the first stage of a rocket (whether it's a return-to-space recovery or a flight-line recovery) requires the use of aerodynamic control mechanisms to control the rocket's attitude and trajectory during reentry. These mechanisms include grid fins, which are folded during ascent and unfolded after stage separation and attitude adjustment. These fins control the rocket's pitch, yaw, and roll, while simultaneously maximizing drag to decelerate the rocket and achieve a precise landing.

[0003] To achieve the above functions, the grid wall thickness of the rudder needs to be increased to reduce the large heat flux caused by the high dynamic pressure during recovery, while simultaneously meeting the aerodynamic, thermal, stiffness, and strength requirements of the recovery process. Currently, the grid wall thickness of some existing rudders is generally greater than 5mm, and the width and height are generally greater than 1m, resulting in a single rudder surface weighing over 100kg. Some existing rudders are manufactured using a welding method; for example, some rudders are manufactured using an aluminum alloy plate insertion and welding process, with a heat-resistant coating applied to the surface.

[0004] The shortcomings of existing grid fins include: numerous welds, long total weld length, complex process, difficulty in controlling the degree of deformation during manual welding, excessive internal stress after welding, and easy generation of defects; a significant increase in the overall weight of the rocket, which directly reduces the overall payload coefficient; strict control of raw material properties and assembly process, and the use of special assembly tooling, resulting in high costs and low processing efficiency. Summary of the Invention

[0005] The purpose of this invention is to propose a hollow grid fin structure for reusable rockets, which solves the problem of high processing difficulty of existing welded grid fins, and is lightweight and low in cost.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A hollow grid fin structure for a reusable rocket includes at least two grid units. Each grid unit includes: two parallel ribs; two parallel skins, each skin connected to the two ribs on both sides, forming a flat cylindrical structure; a bottom baffle connected to an opening on one side of the cylindrical structure formed by the two skins and the two ribs, the bottom baffle, the two skins, and the two ribs forming a flat barrel-shaped structure, with an inlet / outlet at the end away from the bottom baffle; at least one rib located inside the barrel-shaped structure formed by the bottom baffle, the two skins, and the two ribs, with an inlet / outlet channel formed between the rib and the ribs, and between two adjacent ribs; and a cell disposed in the inlet / outlet channel, with opposite ends of the cell abutting against the skins, and gaps formed between the cell and the ribs, or between the cell and the ribs. The hollow grid fin structure is manufactured using 3D printing.

[0008] In one preferred embodiment, the grid unit further includes a stop block located at the inlet / outlet, the stop block being formed by the end of the rib or the reinforcing bar protruding toward the center of the inlet / outlet, and the opposite ends of the stop block being connected to the skin respectively.

[0009] In one preferred embodiment, the ribs, the unit cells, the stiffeners, and / or the stops are all rounded.

[0010] In one preferred embodiment, the bottom guard edge is arc-shaped and protrudes toward the inlet / outlet direction.

[0011] In one preferred embodiment, the unit cell includes four vertical walls connected to the same point, and the unit cell is X-shaped in a cross section parallel to the plane of the skin.

[0012] In one preferred embodiment, each of the inlet and outlet channels is provided with at least two of the unit cells arranged in a row, and the recess between the two vertical walls faces the inlet and outlet.

[0013] In one preferred embodiment, the free end of the vertical wall is an arc-shaped surface.

[0014] In one preferred embodiment, the rib is provided with a powder discharge hole, which is connected to the inlet / outlet channel.

[0015] In one preferred embodiment, the hollow grid rudder structure further includes a frame, the ribs of each grid unit are connected to the ribs of adjacent grid units, all grid units form a grid within the frame, and the inlets and outlets of all grid units open in the same direction.

[0016] In one preferred embodiment, the hollow grid rudder structure further includes a support member connected between the grid unit and the frame.

[0017] The hollow grid fin structure of the reusable rocket disclosed in this invention is manufactured by 3D printing. Compared with the existing welded grid fin structure, the 3D printed hollow grid fin structure can reduce the weight of the structure while meeting the requirements of control use, rigidity and strength performance. The process is simple, the processing cycle is short and the cost is low. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the hollow grid rudder structure provided in a specific embodiment of the present invention;

[0019] Figure 2 This is one of the structural schematic diagrams of the grid unit provided in a specific embodiment of the present invention;

[0020] Figure 3 This is a second structural schematic diagram of the grid unit provided in a specific embodiment of the present invention;

[0021] Figure 4 This is the third structural schematic diagram of the grid unit provided in a specific embodiment of the present invention;

[0022] Figure 5 yes Figure 4 A magnified view of a section at point A in the middle;

[0023] Figure 6 This is the fourth structural schematic diagram of the grid unit provided in a specific embodiment of the present invention;

[0024] Figure 7 yes Figure 6 A magnified view of a section at point B in the middle;

[0025] Figure 8 This is a top view of the internal structure of the grid unit provided in a specific embodiment of the present invention;

[0026] Figure 9 yes Figure 8 A magnified view of a section at point C.

[0027] In the picture:

[0028] 1. Rib; 2. Skin; 3. Bottom edge; 4. Inlet / outlet; 5. Rib; 6. Inlet / outlet channel; 7. Unit cell; 8. Block; 51. Powder discharge hole; 71. Vertical wall; 100. Grid unit; 200. Frame; 300. Support component. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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 invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0035] This embodiment discloses a hollow grid fin structure for a reusable rocket, such as Figure 1 As shown, it includes at least two grid units 100 and a frame 200, with all grid units 100 forming a grid within the frame 200. This hollow grid rudder structure is manufactured using 3D printing. Compared to existing welded grid rudders, the 3D-printed hollow grid rudder structure reduces weight while meeting control requirements, rigidity, and strength performance. It also features a simpler process, shorter processing cycle, and lower cost.

[0036] The specific steps of 3D printing are not limited. In this embodiment, printing starts from the root of the hollow grid rudder structure and continues to the tip. Of course, printing from the tip to the root is also feasible. 3D printing technology is particularly suitable for the one-piece molding of complex thin-walled components. If there are no special assembly requirements after molding, almost no subsequent subtractive processing is needed.

[0037] All grid cells 100 form a mesh within the frame 200, meaning the grid rudder is a hollow structure. To meet requirements for control capability, aerodynamics, thermal performance, structural strength, and stiffness, the grid wall thickness and other dimensions of the grid rudder must remain constant. By adopting a hollow structure, the weight of the grid rudder is reduced by approximately 30%, improving its payload capacity.

[0038] Before starting 3D printing, the stress values ​​at various locations need to be analyzed. Auxiliary supports are added to areas with high stress. This is a standard application in 3D printing and will not be elaborated upon here. Additionally, the support component 300 connects the grid unit 100 and the frame 200 to transfer structural forces, increase strength, and reduce deformation of the hollow grid rudder under stress.

[0039] like Figures 1 to 7 As shown, each grid unit 100 includes two parallel ribs 1, two parallel skins 2, a bottom edge 3, at least one rib 5, and a unit cell 7. The ribs 1 of each grid unit 100 are connected to the ribs 1 of adjacent grid units 100 to form a rudder surface entity.

[0040] Each skin 2 is connected to two ribs 1 on each side, and the two skins 2 and the two ribs 1 form a flat cylindrical structure (open at both ends); the bottom flange 3 is connected to one side opening of the cylindrical structure formed by the two skins 2 and the two ribs 1, and the bottom flange 3, the two skins 2 and the two ribs 1 form a flat barrel structure (open at one end), with the end away from the bottom flange 3 forming an inlet / outlet 4. In this hollow grid rudder structure, the inlet / outlet 4 of all grid units 100 are opened in the same direction.

[0041] At least one rib 5 is located inside the barrel-shaped structure formed by the bottom flange 3, two skin panels 2, and two ribs 1. The two ends of the rib 5 are connected to the two skin panels 2 respectively to enhance the rigidity and strength of the control surface. The extension direction of the rib 5 is basically consistent with the extension direction of the rib 1. An inlet / outlet channel 6 is formed between the rib 5 and the rib 1, as well as between two adjacent ribs 5. Airflow can enter the inlet / outlet channel 6 through the inlet / outlet 4, and powder generated during processing can be removed through the inlet / outlet channel 6.

[0042] The two opposite ends of the unit cell 7 located in the inlet / outlet channel 6 abut against two skin sheets 2, which can support the skin sheets 2 and enhance the rigidity and strength of the rudder surface. A gap is formed between the unit cell 7 and the rib 1, or between the unit cell 7 and the rib 5, to facilitate the cleaning of residual powder inside the rudder surface after 3D printing.

[0043] Based on the above structure, the grid unit 100 also includes a stop block 8 located at the inlet / outlet 4. The stop block 8 is formed by the end of the rib 1 or the stiffener 5 protruding towards the middle of the inlet / outlet 4. In the same inlet / outlet channel 6, the distance between two stop blocks 8 is less than the original width of the inlet / outlet 4, and the opposite ends of the stop blocks 8 are respectively connected to the skin 2, which can effectively reduce the stress concentration at the inlet / outlet 4, prevent the structure from cracking at this point after 3D printing, and extend the service life.

[0044] To avoid significant deformation due to high stress during 3D printing, rib 1, unit cell 7, rib 5, and / or stop block 8 are all rounded. Rounding effectively prevents stress concentration, and the stress dispersion prevents significant deformation of rib 1, unit cell 7, rib 5, and / or stop block 8, thus ensuring the shape and performance of the hollow grid rudder structure.

[0045] The specific shape of the bottom flange 3 is not limited, as long as it can form a flat, barrel-shaped structure with the two skins 2 and the two ribs 1. In this embodiment, the bottom flange 3 is arc-shaped and protrudes towards the inlet / outlet 4, which improves aerodynamics.

[0046] The specific shape of unit cell 7 is not limited; in this embodiment, for example... Figures 7 to 9As shown, the unit cell 7 includes four vertical walls 71. The four vertical walls 71 are connected to the same point, and the unit cell 7 is X-shaped in a cross-section parallel to the plane containing the skin 2. This design maximizes the contact area with the skin 2 while reducing weight, thereby improving the stiffness and structural strength of the control surface, resulting in a wide range of applications and a long service life.

[0047] Each inlet / outlet channel 6 has at least two unit cells 7 arranged in a row, with the recess between the two vertical walls 71 facing the inlet / outlet 4, and the distance between the two blocks 8 is less than the width of the unit cell 7.

[0048] The specific method to achieve "rounding treatment of cell 7" is to make the free end of the vertical wall 71 an arc surface, which is convenient to process, has high processing efficiency, can avoid deformation of cell 7 due to high stress, and has a high yield.

[0049] Based on the above structure, the rib 5 is provided with several powder discharge holes 51, which are connected to the inlet and outlet channels 6. After 3D printing is completed, residual powder inside the rudder surface can be cleaned through the powder discharge holes 51, reducing the processing difficulty.

[0050] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A hollow grid fin structure for a reusable rocket, comprising at least two grid units (100), characterized in that, Each of the grid cells (100) includes: Two parallel ribs (1); Two parallel skins (2) are arranged, and each skin (2) is connected to two ribs (1) on both sides. The two skins (2) and the two ribs (1) form a flat cylindrical structure. The bottom edge (3) is connected to the opening on one side of the cylindrical structure formed by the two skins (2) and the two ribs (1). The bottom edge (3), the two skins (2) and the two ribs (1) form a flat barrel structure, and the end away from the bottom edge (3) forms an inlet and outlet (4). At least one rib (5) is located inside the barrel-shaped structure formed by the bottom flange (3), the two skin panels (2), and the two ribs (1), and an access channel (6) is formed between the rib (5) and the rib (1), and between two adjacent ribs (5); and, A cell (7) is disposed in the inlet / outlet channel (6), and the opposite ends of the cell (7) abut against the skin (2), and a gap is formed between the cell (7) and the rib (1) or between the cell (7) and the rib (5); The hollow grid rudder structure is manufactured using 3D printing.

2. The hollow grid fin structure of the reusable rocket according to claim 1, characterized in that, The grid unit (100) also includes a stop (8) located at the inlet / outlet (4). The stop (8) is formed by the end of the rib (1) or the reinforcing bar (5) protruding towards the middle of the inlet / outlet (4). The opposite ends of the stop (8) are respectively connected to the skin (2).

3. The hollow grid fin structure of the reusable rocket according to claim 2, characterized in that, The ribs (1), the cell (7), the ribs (5) and / or the blocks (8) are all rounded.

4. The hollow grid fin structure of the reusable rocket according to claim 1, characterized in that, The bottom guard (3) is arc-shaped and protrudes towards the inlet / outlet (4).

5. The hollow grid fin structure of the reusable rocket according to claim 1, characterized in that, The unit cell (7) includes four vertical walls (71) connected to the same point. In a cross section along the plane parallel to the skin (2), the unit cell (7) is X-shaped.

6. The hollow grid fin structure of the reusable rocket according to claim 5, characterized in that, Each of the inlet and outlet channels (6) is provided with at least two of the unit cells (7) arranged in a row, and the recess between the two vertical walls (71) faces the inlet and outlet (4).

7. The hollow grid fin structure of the reusable rocket according to claim 5, characterized in that, The free end of the vertical wall (71) is an arc-shaped surface.

8. The hollow grid fin structure of the reusable rocket according to any one of claims 1 to 7, characterized in that, The rib (5) is provided with a powder discharge hole (51), which is connected to the inlet / outlet channel (6).

9. The hollow grid fin structure of a reusable rocket according to any one of claims 1 to 7, characterized in that, The hollow grid rudder structure also includes a frame (200), the rib (1) of each grid unit (100) is connected to the rib (1) of the adjacent grid unit (100), all the grid units (100) form a grid in the frame (200), and the inlet and outlet (4) of all the grid units (100) are opened in the same direction.

10. The hollow grid fin structure of the reusable rocket according to claim 9, characterized in that, The hollow grid rudder structure also includes a support member (300) connected between the grid unit (100) and the frame (200).

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