Positioning tool for mounting sound absorption structure of inner wall of fairing and application

Abstract

A kind of positioning tool for mounting sound absorption structure of fairing inner wall and application, including: external frame, grid plate and arc cover plate.Grid plate is pluggably arranged in external frame to form positioning grid, external frame is fixed to fairing inner wall surface by suction cup, and arc cover plate exerts pressure on sound absorption structure by buckle.The present application utilizes geometric constraint of trapezoidal section of grid plate to ensure that sound absorption structure is directed to fairing central axis in normal direction, realizes quick and accurate positioning installation;Positioning tool can be formed into physical sample by 3D printing, and installed sound absorption structure can be arrayed attached to fairing half-cover inner wall and used as noise reduction product, suitable for engineering installation of fairing noise reduction sound absorption structure.

Description

Technical Field

[0001] This invention relates to a technology in the field of aerospace structural assembly, specifically a positioning tool and its application for installing a sound-absorbing structure on the inner wall of a fairing. Background Technology

[0002] Launch vehicles generate intense acoustic loads during takeoff and flight, and the noise environment inside the fairing directly affects the safety and reliability of the payload. Arraying cuboid sound-absorbing structures onto the inner wall of the fairing is an effective way to reduce internal noise. In existing technologies, the installation of sound-absorbing structures mainly relies on manual measurement and marking for positioning, followed by individual pasting. Since the fairing wall is a cylindrical curved surface, the sound-absorbing structures need to be arranged along the normal direction of the wall, meaning their normal direction should point towards the central axis of the fairing to ensure sound absorption performance. However, existing methods suffer from low efficiency in manual positioning, poor accuracy in marking the curved surface, difficulty in ensuring the accuracy of the normal direction, and insufficient consistency of the adhesive layer due to lack of continuous pressure during pasting. These problems restrict the efficient and high-precision installation of the sound-absorbing structures, necessitating a rapid positioning and auxiliary pressure installation fixture suitable for the curved surface of the fairing. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention proposes a positioning fixture and its application for installing a sound-absorbing structure on the inner wall of a fairing. By combining an external frame with a grid plate to form a positioning mesh, the sound-absorbing structure can be quickly positioned and accurately installed on the curved inner wall of the fairing. This fixture features high positioning accuracy, convenient operation, and reusability.

[0004] This invention is achieved through the following technical solution:

[0005] This invention relates to a positioning fixture for installing a sound-absorbing structure on the inner wall of a fairing, comprising: an outer frame, a grid plate, and an arc-shaped cover plate, wherein: the grid plate is pluggably disposed in the outer frame to form a positioning grid, the outer frame is fixed to the inner wall of the fairing by suction cups, and the arc-shaped cover plate is connected to the outer frame by a snap fastener and applies pressure toward the wall surface to the sound-absorbing structure; the sidewalls of each grid unit used for positioning are parallel to each other, so that the normal of the inserted cuboid sound-absorbing structure points toward the central axis of the fairing.

[0006] The external frame is an arc-shaped plate structure, which appears as part of a ring when viewed from above. The radius of curvature of the outer arc surface is consistent with the radius of the inner wall of the fairing, allowing it to fit tightly against the wall.

[0007] The external frame includes an upper frame, a lower frame, and several horizontal bars disposed between them. The horizontal bars are arranged at equal intervals along the vertical direction to determine the vertical installation position of the sound-absorbing structure. The upper frame, the lower frame, and each horizontal bar are provided with trapezoidal holes in the vertical direction for inserting the grille plate.

[0008] The grating plate is a long strip-shaped plate component with a trapezoidal cross-section.

[0009] The trapezoidal cross-section of the grating plate means that after the grating plate is inserted into the trapezoidal hole of the outer frame, the opposite sides of two adjacent grating plates are parallel to each other, so that the two side walls of the grid unit are parallel, thereby ensuring that the normal of the inserted cuboid sound-absorbing structure is precisely pointed to the central axis of the fairing.

[0010] The geometric relationship between the trapezoidal holes and the trapezoidal cross-section of the grating plate satisfies the following condition: Let the length of the cuboid sound-absorbing structure be... (Horizontal direction), width is (Vertical direction), height is (Perpendicular to the wall panel direction), the horizontal spacing of the top side of the sound-absorbing structure after installation is: The vertical spacing is The thickness of the horizontal strip is then... The horizontal bar spacing is The dimensions and insertion position of the trapezoidal cross-section of the grid plate are determined by the geometric constraint that the sidewalls of the grid cells are parallel to and point towards the central axis of the wall.

[0011] Each of the four corners of the external frame is provided with a suction cup for detachably fixing the external frame to the inner wall of the fairing.

[0012] The lower right corner of the external frame is provided with a positioning strip, which is used to confirm the spacing and horizontal alignment between adjacent positioning fixtures when multiple positioning fixtures are used together.

[0013] The curvature of the inner surface of the arc-shaped cover plate is adapted to the outline of the exposed surface of the sound-absorbing structure after installation. It is connected to the external frame by a buckle, and applies uniform pressure towards the wall surface to the sound-absorbing structure to assist the curing of the adhesive layer.

[0014] This invention relates to the application of the above-mentioned positioning fixture, including:

[0015] Step 1: Insert the grating panels one by one into the trapezoidal holes of the outer frame to form a positioning grid together with the horizontal bars.

[0016] Step 2: Fix the positioning fixture to the target area on the inner wall of the fairing using the suction cups at the four corners of the external frame; when multiple positioning fixtures are used together, confirm the spacing and horizontal alignment of adjacent fixtures using the positioning strips.

[0017] Step 3: Apply adhesive to the bottom surface of the sound-absorbing structure, and insert the sound-absorbing structure into the grid unit one by one, so that its bottom surface is attached to the wall surface.

[0018] Step 4: Place the arc-shaped cover plate on the outside of the sound-absorbing structure, connect it to the external frame with the buckle, apply uniform pressure to the sound-absorbing structure, and keep it until the adhesive is completely cured.

[0019] Step 5: After curing, remove the curved cover plate, pull out the grid plate, unlock the suction cup, and remove the outer frame in sequence. Technical effect

[0020] This invention achieves rapid and precise installation of the sound-absorbing structure on the inner wall of the fairing by combining an external frame with trapezoidal cross-section grating plates to form a curved, adaptable positioning grid. Compared to existing technologies, this invention automatically ensures that the normal direction of the sound-absorbing structure points to the central axis through trapezoidal cross-section geometric constraints; it uses pluggable grating plates and suction cups for easy installation and disassembly, and the tooling is reusable; it uses positioning strips to achieve spacing and level calibration between multiple toolings; it uses an arc-shaped cover plate for pressure to ensure the quality of the adhesive layer; and it does not change the original structure of the fairing. This invention provides a new approach to the engineering installation of fairing sound-absorbing structures and has significant engineering application value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the positioning tooling structure of the present invention;

[0022] Figure 2 This is a three-dimensional view of the external frame of the present invention;

[0023] Figure 3 This is a schematic diagram of the cross-section of the grating plate and a geometric relationship diagram of the trapezoidal cross-section of the present invention;

[0024] Figure 4 A schematic diagram showing the positioning grid formed after the grating is inserted into the external frame;

[0025] Figure 5 This is a schematic diagram of the installation process of the present invention. Figure 1 The positioning fixture is fixed to the wall surface;

[0026] Figure 6 This is a schematic diagram of the installation process of the present invention. Figure 2 : Sound-absorbing structure inserted into the grid;

[0027] Figure 7 This is a schematic diagram of the installation process of the present invention. Figure 3 Curved arc-shaped cover plate under pressure;

[0028] Figure 8 This is a schematic diagram of the installation process of the present invention. Figure 4 : Layout effect diagram of the sound-absorbing structure on the inner wall of the fairing after the tooling is removed;

[0029] Figure 9 This is a physical image of the positioning tooling of the present invention after being 3D printed;

[0030] Figure 10 A real-world photograph of the noise reduction product structure formed by attaching the sound-absorbing structure array to the inner wall of the fairing half-cover.

[0031] In the diagram: 1. External frame, 2. Grille, 3. Arc-shaped cover, 4. Suction cup, 5. Buckle, 6. Horizontal bar, 7. Trapezoidal hole, 8. Positioning bar, 9. Rectangular sound-absorbing structure, 10. Inner wall of fairing. Detailed Implementation

[0032] like Figures 1 to 10 As shown, this embodiment relates to a positioning fixture for installing a sound-absorbing structure on the inner wall of a fairing, comprising: an outer frame 1, a grid plate 2, and an arc-shaped cover plate 3, wherein: the grid plate 2 is pluggably disposed in the trapezoidal holes 7 of the outer frame 1 to form a positioning grid, the outer frame 1 is fixed to the inner wall surface 10 of the fairing by suction cups 4 at the four corners, and the arc-shaped cover plate 3 is connected to the outer frame 1 by buckles 5.

[0033] The external frame 1 is an arc-shaped plate structure, such as... Figure 2 As shown, the top-view projection is part of a circular ring. In this embodiment, the radius of curvature of the outer arc surface of the outer frame 1 is consistent with the inner diameter of the fairing column section, which has a diameter of 4.2m and a radius of curvature of 2.1m.

[0034] The external frame 1 includes an upper frame, a lower frame, and several horizontal strips 6 disposed between them. The number of horizontal strips 6 is determined according to the number of rows of the sound-absorbing structure array, and the thickness is equal to the vertical spacing. The net spacing between the horizontal bars is equal to the width of the sound-absorbing structure. The top frame, bottom frame, and each horizontal strip 6 are all provided with trapezoidal holes 7 that run vertically through them.

[0035] The aforementioned grating plate 2 is a long strip-shaped plate component, such as... Figure 3 As shown, the cross-section is trapezoidal.

[0036] like Figure 3 As shown, the trapezoidal cross-section of the grating plate 2 is determined by the following constraints: Let the length of the cuboid sound-absorbing structure 9 be... (Horizontal direction), width is (Vertical direction), height is (Perpendicular to the wall panel direction), the horizontal spacing of the top side after installation is... The vertical spacing is The sound-absorbing structure needs to point towards the central axis, therefore the opposite sides of adjacent grid panels 2 must be parallel, making the two side walls of each grid unit parallel. This constraint requires that the cross-section of the grid panel 2 be trapezoidal, and the difference between the upper and lower bases of the trapezoid is determined by the radius of curvature of the wall panel and the central angle between adjacent grid panels.

[0037] In this embodiment, the length of the cuboid sound-absorbing structure 9 is... mm, width mm, height mm, horizontal spacing of top side edge mm, vertical spacing mm. The outer frame 1 covers an arc section of the fairing column, and can accommodate multiple rows and columns of sound-absorbing structures in the circumferential and axial directions, respectively.

[0038] The suction cups 4 are located at the four corners of the outer frame 1, and the outer frame 1 is detachably fixed to the inner wall 10 of the shroud by vacuum adsorption.

[0039] The positioning strip 8 is located at the lower right corner of the outer frame 1. When multiple positioning fixtures are spliced ​​together along the circumference or axial direction of the fairing, the positioning strip 8 is used to confirm the spacing between adjacent fixtures and whether they are horizontally aligned, ensuring the installation consistency of the sound-absorbing structure throughout the entire circumference of the fairing.

[0040] The inner surface curvature of the arc-shaped cover plate 3 is adapted to the outline of the exposed surface of the sound-absorbing structure 9 after installation. It is connected to the outer frame 1 through the buckle 5, applying uniform pressure towards the wall to the entire sound-absorbing structure. The arc-shaped cover plate 3 is made of lightweight composite material.

[0041] This embodiment, based on the application of the above-mentioned positioning fixture, specifically includes:

[0042] Step 1: Insert the grating plates 2 one by one into the trapezoidal holes 7 of the outer frame 1. The trapezoidal cross section and the trapezoidal holes 7 are positioned together to form a positioning grid with the horizontal bars 6.

[0043] Step 2: Press the suction cups 4 at the four corners of the outer frame 1 on the target area of ​​the inner wall 10 of the fairing to fix the outer frame 1 to the wall, and the normal of each unit of the positioning grid will automatically point to the central axis. When multiple positioning fixtures are used together, use the positioning strips 8 to calibrate the spacing and horizontal position of adjacent fixtures.

[0044] Step 3: Apply adhesive evenly to the bottom surface of the sound-absorbing structure 9, insert the grid units one by one, and make sure the bottom surface is in contact with the inner wall surface 10 of the fairing.

[0045] Step 4: Place the arc-shaped cover plate 3 on the outside of the sound-absorbing structure 9, and connect and fix it to the outer frame 1 through the buckle 5. Apply uniform pressure to the sound-absorbing structure and keep it until the adhesive is completely cured.

[0046] Step 5: After curing, first release the clips 5 and remove the arc-shaped cover plate 3; then pull out the grid plates 2 one by one from above, ensuring the trapezoidal cross-section makes the extraction direction perpendicular to the normal of the sound-absorbing structure, preventing lateral interference; finally, unlock the suction cups 4 and remove the outer frame 1 from the front. Figure 8 As shown, after removal, the sound-absorbing structure 9 is neatly pasted onto the inner wall surface 10 of the fairing, and the normal of each sound-absorbing structure points to the central axis.

[0047] The aforementioned positioning fixture can be reused and moved to an adjacent area to continuously complete the installation of the full-circumference sound-absorbing structure of the fairing.

[0048] like Figure 9 As shown, the positioning fixtures such as the external frame and grating in this embodiment can be 3D printed to form physical prototypes. The physical prototype shows the forming state of the external frame's curved surface, trapezoidal holes, grating's plug-in fit, and positioning mesh, which can be used to verify the fixture's curvature adaptation, structural manufacturability, and on-site assembly feasibility.

[0049] like Figure 10 As shown, after installation using the aforementioned positioning fixture, multiple cuboid sound-absorbing structures can be arrayed and attached to the inner wall of the fairing half-cover, forming a specific sound-absorbing product structure for fairing noise reduction. This on-site photograph reflects the arrangement of the sound-absorbing structures on the curved surface of the half-cover, their attachment status, and their connection with the inner wall of the fairing.

[0050] Compared with existing technologies, this invention uses an external frame and trapezoidal cross-section grid plates to form a curved, adaptable positioning grid. Geometric constraints automatically ensure that the normal of the sound-absorbing structure points to the central axis. A suction cup for detachable fixing and an arc-shaped cover plate for pressurization are employed. This allows for rapid and precise installation of the sound-absorbing structure without altering the original fairing structure. 3D-printed prototypes can verify the machining and assembly of the tooling structure, while the fairing half-cover on-site demonstrates the specific application of the sound-absorbing structure as a noise reduction product. This invention improves installation efficiency, positioning accuracy, and adhesive layer quality consistency, possessing significant engineering application value.

[0051] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A positioning fixture for installing a sound-absorbing structure on the inner wall of a fairing, characterized in that, include: The external frame, the grating, and the arc-shaped cover plate are configured to form a positioning grid in the external frame. The external frame is fixed to the inner wall of the fairing by suction cups. The arc-shaped cover plate is connected to the external frame by snaps and applies pressure to the sound-absorbing structure towards the wall. The sidewalls of each grid unit used for positioning are parallel to each other, so that the normal of the inserted cuboid sound-absorbing structure points to the central axis of the fairing.

2. The positioning fixture according to claim 1, characterized in that, The external frame is an arc-shaped plate structure, which appears as part of a ring when viewed from above. The radius of curvature of the outer arc surface is consistent with the radius of the inner wall of the fairing, allowing it to fit tightly against the wall.

3. The positioning fixture according to claim 1, characterized in that, The external frame includes an upper frame, a lower frame, and several horizontal bars disposed between them. The horizontal bars are arranged at equal intervals along the vertical direction to determine the vertical installation position of the sound-absorbing structure. The upper frame, the lower frame, and each horizontal bar are provided with trapezoidal holes in the vertical direction for inserting the grille plate.

4. The positioning fixture according to claim 3, characterized in that, The grating plate is a long strip-shaped plate component with a trapezoidal cross-section. Specifically, after the grating plate is inserted into the trapezoidal hole of the outer frame, the opposite sides of two adjacent grating plates are parallel to each other, so that the two side walls of the grid unit are parallel, thereby ensuring that the normal of the inserted cuboid sound-absorbing structure is precisely pointed to the central axis of the fairing.

5. The positioning fixture according to any one of claims 1-4, characterized in that, The outer frame has suction cups at its four corners and a positioning strip at the lower right corner for aligning the spacing and horizontal alignment of adjacent positioning fixtures. The positioning strip at the lower right corner of the outer frame is used to confirm the spacing and horizontal alignment between adjacent fixtures when multiple positioning fixtures are used together. The curvature of the inner surface of the arc-shaped cover plate is adapted to the outline of the exposed surface of the sound-absorbing structure after installation. It is connected to the outer frame by a buckle, applying uniform pressure towards the wall surface to the sound-absorbing structure to assist in the curing of the adhesive layer.

6. An application of the positioning fixture based on any one of claims 1 to 5, characterized in that, include: Step 1: Insert the grating panels one by one into the trapezoidal holes of the outer frame to form a positioning grid together with the horizontal bars; Step 2: Fix the positioning fixture to the target area on the inner wall of the fairing using the suction cups at the four corners of the external frame; When multiple positioning fixtures are used together, the spacing and horizontal alignment of adjacent fixtures are confirmed by the positioning strip; Step 3: Apply adhesive to the bottom surface of the sound-absorbing structure, and insert the sound-absorbing structure into the grid unit one by one, so that its bottom surface is attached to the wall surface; Step 4: Place the arc-shaped cover plate on the outside of the sound-absorbing structure, connect it to the outer frame with the buckle, apply uniform pressure to the sound-absorbing structure, and hold it until the adhesive is completely cured; Step 5: After curing, remove the curved cover plate, pull out the grid plate, unlock the suction cup, and remove the outer frame in sequence.

7. The application according to claim 6, characterized in that, When multiple positioning fixtures are used together, the positioning strip 8 is used to calibrate the spacing and horizontal position of adjacent fixtures.

8. The application according to claim 6 or 7, characterized in that, The sound-absorbing structure is attached to the inner wall of the fairing half-cover to form an array-type noise reduction and sound-absorbing structure, which is used as a fairing noise reduction product.

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