A method for designing a one-piece metal plate of a shelter step and air duct

Abstract

This invention discloses a method for integrated sheet metal design of stepped air ducts in modular shelters, belonging to the field of modular shelters. In the design of the stepped air duct sheet metal structure, this method creates a solid model of the stepped air duct based on a 3D model of the modular shelter. Then, using the inner and outer contours of the solid model as references, a solid inversion template model is created. This inversion template model is then converted into sheet metal and designed within a sheet metal environment, achieving two-dimensional unfolding of the integrated sheet metal structure of the stepped air duct. This invention, through the inversion template sheet metal method, achieves an integrated sheet metal structure design for the stepped air duct in modular shelters, solving the problem of inconsistent interfaces between different sections of the air duct caused by the segmented sheet metal structure design and production of existing stepped air ducts. It also avoids the difficulties in connecting the interfaces during assembly of segmented air ducts into the upper cabin and the challenges of welding operations in the confined space within the modular shelter.

Description

Technical Field

[0001] This invention relates to the field of modular shelters, specifically to a method for designing an integrated sheet metal structure for a modular shelter's stepped ventilation duct. Background Technology

[0002] As a versatile loading platform, the modular container plays a vital role. In its design, the air circulation system, especially the stepped air duct design, is a crucial aspect. The stepped air duct, while meeting ergonomic requirements, must have a large cross-section to ensure smooth airflow, and its design must also be simple and easy to manufacture.

[0003] For a type of modular cabin stepped ventilation duct, the structure is as follows: Figure 1 , Figure 2 As shown ( Figure 1 (This is a diagram illustrating the installation of a stepped air duct within a shelter.) This stepped air duct includes a front stepped air duct 2, a left-side air duct 3, and a right-side air duct 1. Existing sheet metal design methods for stepped air ducts in shelters model the front, left, and right sections as independent sheet metal structures. The joints between the front and left-side sections, and between the front and right-side sections, are located at corners. This design method involves independently modeling and manufacturing the three air duct sheet metal structures, followed by welding and assembly within the shelter. However, this existing method not only wastes sheet metal during bending in the manufacturing process but also results in inconsistent cross-sectional dimensions at the joints of the three sections. This leads to difficulties in assembling the air duct sections later on, requiring repeated adjustments and resulting in significant waste of manpower, resources, and finances. In addition, the welding and connection of the three independent air ducts inside the cabin also poses risks such as the confined space making operation difficult, affecting other components inside the cabin, causing fires, and generating toxic and harmful gases that could cause injury to personnel.

[0004] for Figure 2 The stepped air duct shown, when using traditional 3D modeling methods, can only achieve independent sheet metal structure design for three sections of the duct, and cannot create an integrated sheet metal structure for the stepped air duct in a container. This is because when generating an overall stepped air duct structure using traditional 3D modeling methods, direct sheet metal design, when creating sheet metal bends, results in issues such as… Figure 3 The conventional sheet metal model shown cannot add bends (referring to the arc transition between adjacent sides of the air duct), nor can it create the connection surface between the rear panel of the container and the right / left air duct (i.e., the flange at the rear end of the left and right air ducts) using sheet metal. Therefore, it is impossible to form a one-piece sheet metal structure. Thus, a one-piece sheet metal design method for the stepped air duct of the container is needed to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides an integrated sheet metal design method for modular cabin stepped air ducts. In the sheet metal structure design of modular cabin stepped air ducts, the inverted template sheet metal method is used to realize the integrated sheet metal structure design of modular cabin stepped air ducts. This solves the problem of interface consistency of each section of the air duct caused by the segmented sheet metal structure design and production of existing modular cabin stepped air ducts. It also avoids the problems of difficult docking at the interface when assembling the upper cabin of segmented air ducts and the difficulty of welding operations in the narrow space inside the modular cabin.

[0006] The technical solution of this invention is: a method for designing an integrated sheet metal ventilation duct for a modular cabin, comprising: Based on the design dimensions of the air duct structure, and using the three-dimensional model of the container as a reference, an integral stepped air duct solid model is created. The stepped air duct solid model includes a front stepped air duct section solid model, a left air duct section solid model, and a right air duct section solid model. The three air duct solid models are provided with flanges that connect with the container wall on the docking surfaces of the container. Using the inner outer contour of the side of the stepped air duct solid model facing away from the container wall as a reference, a solid inversion template model is created. The solid inversion template model is set to correspond with the three-section air duct solid models. The side of the solid model facing the stepped air duct solid model is completely consistent with the inner outer contour of the stepped air duct solid model. The side of the solid model facing away from the stepped air duct solid model is the vertically intersecting plane created by the flange edges on both sides of the corresponding solid model in the vertical and horizontal directions, respectively. The solid inversion template model completely covers the stepped air duct solid model. Convert the solid inverted template model into a sheet metal model by performing a shelling operation on the solid inverted template model and removing the extra faces that do not contact the solid model of the stepped air duct. In the sheet metal modeling environment, the excess connecting surfaces that connect to the bulkhead in the converted sheet metal model are repaired, and then arc bends are created at all adjacent surface connections. Then, the sheet metal model after bending is torn using the tearing method in the 3D modeling software, and then unfolded in two dimensions to obtain the integrated sheet metal structure of the cabin step air duct.

[0007] A further technical solution of the present invention is: the method for creating a solid model of a stepped air duct includes: Using the inner wall of the front panel of the modular container as the reference plane, and according to the cross-sectional shape of the right-side air duct, the model is created using the extrusion function, with the extrusion length extending to the inner side of the rear panel of the modular container, thus completing the creation of the solid model of the right-side air duct section. Using the yz plane as the reference plane, and according to the cross-sectional shape of the front stepped air duct, the right half of the front stepped air duct section solid model is created by stretching the length to the right air duct section solid model and fitting it to the inner side. The yz plane is a plane that is perpendicular to the front stepped air duct section solid model and passes through the center of the front stepped air duct section solid model. Select the right half of the existing right air duct section solid model and the front step air duct section solid model, and mirror them with the yz plane as the symmetry plane to create the left air duct section solid model and the left half of the front step air duct section solid model, thus completing the solid model creation.

[0008] A further technical solution of the present invention is: the solid inversion template model includes a left air duct inversion template, a right air duct inversion template, and a front air duct inversion template; the solid inversion template model creation method includes: Using the inner and outer contours of the solid model of the left air duct section as a reference and the inner and outer contours of the solid model of the right air duct section as a reference, the left air duct inversion template and the right air duct inversion template are created by extrusion, with the extrusion length being the same as that of the solid models on both sides. Then, using the inner outer contour of the front step air duct section solid model as a reference, the front air duct inversion template is created by stretching it to both sides and connecting it to the outer sides of the left and right air duct inversion templates. Then, using the outer contour of the front air duct inversion template as a reference, stretch and cut to the inner side of the left and right air duct inversion templates to remove excess surfaces and complete the creation of the solid inversion template model.

[0009] A further technical solution of the present invention is: when the left air duct reversal template is created by stretching, its stretching section is: the inner outer contour of the solid model of the left air duct section is used as the boundary line facing the cabin in the stretching section of the left air duct reversal template, and the upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the cabin in the stretching section of the left air duct reversal template, which together enclose the stretching section of the left reversal template.

[0010] A further technical solution of the present invention is: when the right air duct reversal template is created by stretching, its stretching section is: the inner outer contour of the solid model of the right air duct section is used as the boundary line facing the cabin in the stretching section of the right air duct reversal template, and the upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the cabin in the stretching section of the right air duct reversal template, which together enclose the stretching section of the right reversal template.

[0011] A further technical solution of the present invention is: when the front air duct reversal template is created by stretching, its stretching section is: the inner outer contour of the solid model of the front step air duct section is used as the boundary line facing the cabin in the stretching section of the front step air duct reversal template. The upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the cabin in the stretching section of the front air duct reversal template, which together form the stretching section of the front air duct reversal template.

[0012] A further technical solution of the present invention is: the excess connecting surfaces in the modified sheet metal model that are connected to the bulkhead include: removing the excess surfaces connecting the front step air duct section to the front bulkhead in the sheet metal model by stretching; and then removing the excess surfaces connecting the rear ends of the left and right air duct sections to the rear bulkhead in the sheet metal model by stretching.

[0013] A further technical solution of the present invention is: the steps of the tearing method include: The four corners of the sheet metal model, including the left and right air duct sections, were constructed using the edge tearing technique. Curved surface tearing was used to remove the curved surfaces at the connection points of the left and right side air duct sections and the front stepped air duct section in the sheet metal model. The tearing connection method is used to complete the tearing of the flange connected to the front panel in the sheet metal model, and also to complete the tearing of the flange connected to the rear panel in the sheet metal model. Use sketch tearing to complete the tearing on the bottom surface of the left air duct section in the sheet metal model, and continue using sketch tearing to complete the tearing on the end surface of the left air duct section.

[0014] A further technical solution of the present invention is: the method for constructing a three-dimensional model of a container is as follows: if the container is a right-angle container, the front or rear shape of the container is used as a cross section for stretching, then the shell is removed, and then the rear panel is removed; if the container is a single-beveled container, the front or rear shape of the container is used as a cross section for stretching, then the bevel is formed by chamfering, then the shell is removed, and then the rear panel is removed.

[0015] The beneficial effects of this invention are as follows: This invention provides a method for designing an integrated sheet metal structure for a modular air duct with stepped sections. Based on a solid model of the air duct, a reverse template model is created. This reverse template model can be converted into a sheet metal model. The resulting sheet metal model allows for the creation of arc bends within a sheet metal modeling environment. Using conventional tearing methods, the integrated sheet metal structure of the modular air duct with stepped sections can be unfolded into a two-dimensional plane for use in the production and manufacturing of modular air ducts. The integrated sheet metal structure designed using this method avoids the inconsistencies in bending of traditional segmented modular air duct designs, particularly the inconsistent joint interfaces at corners in three-section split structures. The integrated sheet metal structure designed using this method can be welded externally to the modular air duct before installation, avoiding various risks associated with welding within the confined space of the modular air duct.

[0016] The integrated sheet metal structure designed using this method saves materials and reduces waste of manpower and resources, resulting in significant cost reduction and efficiency improvement. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a modular cabin stepped ventilation duct installed inside the modular cabin as described in this invention; Figure 2 This is a schematic diagram of the structure of the modular cabin stepped air duct described in this invention; Figure 3 As an integrated stepped air duct, it is impossible to generate a bending construction diagram under the sheet metal model of traditional 3D modeling methods; Figure 4 A schematic diagram illustrating the creation of a 3D model of the modular shelter in this invention; Figure 5 A schematic diagram of the creation of the solid model of the cabin step air duct in this invention is shown in the figure. (1) is the tensile section of the solid model of the right air duct section, (2) is the tensile section of the solid model of the front step air duct section, and (3) is the overall structural diagram of the solid model of the cabin step air duct. Figure 6 This is a schematic diagram of the creation of the solid inversion template model in this invention. In the figure, (1) is a stretched cross section of the left and right side air duct inversion templates, (2) is a stretched cross section of the front air duct inversion template, (3) is an overall structural diagram of the solid inversion template model, and (4) is a schematic diagram of the solid inversion template model created on the stepped air duct solid model. Figure 7 This is a schematic diagram of the construction of the solid inversion template model into a sheet metal model in this invention. In the figure, (1) and (2) show the six redundant surfaces that do not contact the solid model that need to be removed after the solid inversion template model is converted into a sheet metal model. They are: bottom surface 611 of the front air duct inversion template, inner side surface 612 of the front air duct inversion template, bottom surface 621 of the left air duct inversion template, inner side surface 622 of the left air duct inversion template, bottom surface 631 of the right air duct inversion template, and inner side surface 632 of the right air duct inversion template. In the figure, (3) shows the air duct surface that is retained after removing the six redundant surfaces.

[0019] Figure 8 is a schematic diagram of the process of constructing an integrated stepped air duct sheet metal model after converting the solid inversion template model into sheet metal in this invention. In the figure, ( Figure 8a This demonstrates the steps involved in repairing the excess surfaces connecting the front stepped air duct section to the front bulkhead after sheet metal work. Figure 8b This demonstrates the steps involved in trimming excess surfaces connecting the rear ends of the left and right side air duct sections to the aft bulkhead after sheet metal work. Figure 8c This demonstrates the steps for creating a 0.5mm bend after converting to sheet metal. Figure 8d The document demonstrates the construction steps involved in tearing the left and right corners of the air duct section after sheet metal transfer. Figure 8e This demonstrates the steps for removing the curved surfaces at the connection points between the left and right side air duct sections and the front stepped air duct section after sheet metal transfer. Figure 8f This demonstrates the tearing process of the flange connecting the front and rear hatch panels after sheet metal transfer. Figure 8g The process of tearing the bottom surface of the left-side air duct section after sheet metal transfer was demonstrated. Figure 8h This demonstrates the tearing process on the end face of the left air duct section after the sheet metal transfer. Figure 9 This is a two-dimensional unfolded schematic diagram of the integrated sheet metal structure model of the stepped air duct in this invention.

[0020] In the diagram: 1. Right side air duct; 2. Forward stepped air duct; 21. Connection surface between the forward stepped air duct and the bulkhead; 22. Inner side of the forward stepped air duct; 23. Bottom surface of the forward stepped air duct; 24. Small inclined surface of the forward stepped air duct; 3. Left side air duct; 31. Connection surface between the left side air duct and the bulkhead; 32. Inner side of the left side air duct; 33. Bottom surface of the left side air duct; 4. Container (removed rear hatch); 5. Solid model of stepped air duct; 51. Solid model of forward stepped air duct section; 52. Solid model of left side air duct section; 53. Solid model of right side air duct section; 6. Solid inverted template model; 61. Forward air duct inverted template; 611. Bottom surface of forward air duct inverted template; 612. Inner side of forward air duct inverted template; 62. Left side air duct inverted template; 621. Left side air duct. 622. The inner side of the left air duct reverse template, 63. The right air duct reverse template, 631. The bottom of the right air duct reverse template, 632. The inner side of the right air duct reverse template, 7. The redundant surface connecting the front stepped air duct section and the front bulkhead in the sheet metal model, 8. The redundant surface connecting the rear end of the left and right air duct sections and the rear bulkhead in the sheet metal model, 9. One of the four corners of the left and right air duct sections in the sheet metal model, 10. The curved surface at the connection between the left and right air duct sections and the front stepped air duct section in the sheet metal model, 11. The flange connecting to the front bulkhead in the sheet metal model, 12. The flange connecting to the rear bulkhead in the sheet metal model, 13. The tear line on the bottom surface of the left air duct section in the sheet metal model, 14. The tear line on the end surface of the left air duct section in the sheet metal model, 15. The yz plane. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] An embodiment of the present invention provides a method for designing an integrated sheet metal structure for a modular air duct with stepped access in a container, which is used to create an integrated sheet metal structure for the modular air duct with stepped access in a container. The structure of the modular air duct with stepped access in a container is as follows: Figure 1 , Figure 2 As shown, the stepped air duct includes a right-side air duct 1, a front-end stepped air duct 2, and a left-side air duct 3. In existing design methods, the three air duct sections are designed and fabricated independently, and then assembled within the container 4. Firstly, the independently segmented sheet metal design of the air ducts easily leads to material waste, and inconsistencies in cross-sectional dimensions at the interfaces during assembly can cause difficulties in docking. Secondly, assembling the three independent air duct sections within the container 4 presents challenges due to the limited space and operational difficulties. Furthermore, using existing traditional 3D modeling methods, after generating the overall stepped air duct structure, when creating sheet metal bends using direct sheet metal design, issues such as closed bend boundaries can arise... Figure 3 The inability to add bends, as shown, prevents the overall conversion to sheet metal, which makes it impossible to create a unified stepped air duct sheet metal structure.

[0023] The method of this invention provides a solution for the integrated sheet metal design of modular cabin air ducts by creating a solid inversion template model on a three-dimensional solid air duct model. At the same time, this method can also be applied to air ducts of other modular cabin structures.

[0024] This invention provides a method for designing an integrated sheet metal structure for a modular air duct with stepped access. The main steps of the method include: constructing a three-dimensional model of the modular air duct 4 → creating a solid model 5 of the stepped air duct → creating a solid inversion template model 6 → converting the solid inversion template model 6 into sheet metal → designing the sheet metal after conversion → creating a three-dimensional flattened two-dimensional machining drawing (i.e., an integrated sheet metal structure). The integrated sheet metal structure can then be machined and formed as a whole.

[0025] The following is for reference. Figure 4 - Figure 9 ,by Figure 2 Taking the stepped air duct structure of a container as an example, this paper provides a detailed introduction to the integrated sheet metal design method of the stepped air duct in the container of the present invention.

[0026] Step 1: Create a 3D model of Fangcang 4.

[0027] The design is based on the structural requirements of Container 4. If Container 4 is a right-angled container, it is stretched using the front or rear profile as the cross-section, then shelled, and finally the rear face (i.e., the rear panel) is removed. If the container is a single-beveled container, it is stretched using the front or rear profile as the cross-section, then chamfered to form a single bevel, then shelled, and finally the rear panel is removed. This embodiment illustrates this. Figure 4 The image shown is of a single-cornered container. Extrusion, shelling, removal, and chamfering are all drafting functions in 3D modeling software.

[0028] Step 2: Based on the structural dimensions of the air duct design, and using the three-dimensional model of the cabin 4 as a reference, create an integral three-dimensional stepped air duct solid model 5.

[0029] Stepped air duct solid model 5 Figure 2 The three-dimensional solid structure of the mid-step air duct, such as Figure 5 As shown in Figure (3), it includes a front stepped air duct section solid model 51, a left air duct section solid model 52, and a right air duct section solid model 53. All three air duct sections have flanges on their docking surfaces with the container cabin 4. Specifically, the upper edge away from the front bulkhead and the lower edge of the front bulkhead of the front stepped air duct section solid model 51 have flanges; the upper edge of the top bulkhead and the lower edge of the left bulkhead of the left air duct section solid model 52 have flanges; and the upper edge of the top bulkhead and the lower edge of the right air duct section solid model 53 have flanges. The setting of the flanges on the stepped air duct solid model 5 is related to... Figure 2 The connection surfaces of each air duct and the bulkhead are consistent (including the connection surface 21 between the front stepped air duct and the bulkhead, the connection surface 31 between the left air duct and the bulkhead, and the connection surface between the right air duct and the bulkhead; each connection surface is the designed flange structure; the flange here does not include the flange of the connection surface between the left and right side air ducts and the rear bulkhead of the container). like Figure 5 As shown, the specific creation method of the stepped air duct solid model 5 includes: Step 2.1: Using the inner wall of the front panel of the container as the reference plane, and according to the cross-sectional shape of the right air duct 1, use the extrusion function to create the model, and extend the length to the inner side of the rear panel of the container to complete the creation of the solid model 53 of the right air duct section. Figure 5 (1) shows the tensile cross-sectional shape of the solid model of the right air duct section. The upper left and lower right corners of the figure are the flange positions.

[0030] Step 2.2: Using the yz plane 15 as the reference plane, according to the cross-sectional shape of the front stepped air duct 2, use the extrusion function to create the right air duct section solid model 53 and make it fit the inner side (the inner side of the right air duct section solid model 53 refers to the side facing away from the right bulkhead of the container 4 and towards the inside of the container), thus completing the creation of the right half of the front stepped air duct section solid model 51; the yz plane 15 is a plane that is perpendicular to the front stepped air duct section solid model 51 and passes through the center of the front stepped air duct section solid model 51. Figure 5 (2) shows the tensile cross-sectional shape of the front step air duct section solid model. The upper left and lower right corners of the figure are the flange positions.

[0031] Select the right half of the existing right-side air duct segment solid model 53 and the front-end stepped air duct segment solid model 51, and mirror them with the yz plane 15 as the symmetry plane to create the left-side air duct segment solid model 52 and the left half of the front-end stepped air duct segment solid model, thus completing the creation of the stepped air duct solid model 5. Figure 5 (3) The final solid model of the cabin step ventilation duct is shown in the overall structural diagram.

[0032] Step 3: Create the entity inversion template model 6.

[0033] like Figure 6 As shown in (4), a solid inversion template model 6 is created based on the inner outer contour of the side of the solid model 5 facing away from the bulkhead of the container 4. The solid inversion template model 6 is set up in correspondence with the three sections of the solid model, specifically including the left airway inversion template 62, the right airway inversion template 63, and the front airway inversion template 61. The side of each section of the solid inversion template model 6 facing the solid model 5 is completely consistent with the inner outer contour of the solid model 5. The side facing away from the solid model 5 is the vertically intersecting plane created by the flange edges on both sides of the corresponding solid model in the vertical and horizontal directions, respectively. The solid inversion template model 6 completely covers the solid model 5.

[0034] Specifically, the method for creating Entity Inversion Template Model 6 includes: Step 3.1: Using the inner outer contour of the left air duct section solid model 52 and the inner outer contour of the right air duct section solid model 53 as references, create the left air duct inversion template 62 and the right air duct inversion template 63 by extrusion. The extrusion length is the same as that of the two solid models. The left air duct inversion template 62 and the right air duct inversion template 63 are mirror-symmetrical with respect to the yz plane 15.

[0035] like Figure 6 As shown in (1), when the left air duct inversion template 62 is created by extrusion, its extruded section is as follows: the inner outer contour of the solid model 52 of the left air duct section (the inner outer contour refers to the section boundary line of the solid model 52 of the left air duct section facing the inner cavity of the cabin) is used as the boundary line of the extruded section of the left air duct inversion template 62 facing the inner wall of the cabin 4 (that is, facing away from the inner cavity of the cabin). The upper edge of this boundary line and the lower edge of this boundary line (corresponding to the two flange edges of the solid model 52 of the left air duct section) are connected by two mutually perpendicular line segments to form the boundary line of the extruded section of the left air duct inversion template 62 facing away from the inner wall of the cabin 4 (that is, facing the inner cavity of the cabin). The boundary lines facing away from and facing the inner wall of the cabin together form the extruded section of the left inversion template, as shown in the figure. Figure 6 (1) Pink irregular cross section shown on the left.

[0036] The extruded section of the right-side air duct inversion template 63 is the same as that of the left side, and the two are mirror images of each other. When the right-side air duct inversion template 63 is created by extrusion, its extruded section is as follows: the inner outer contour of the right-side air duct section solid model 53 (the inner outer contour refers to the section boundary line of the right-side air duct section solid model 53 facing the inner cavity of the cabin) is used as the boundary line of the right-side air duct inversion template 63 facing the inner wall of the cabin (i.e., facing away from the inner cavity of the cabin). The upper edge of this boundary line and the lower edge of this boundary line (corresponding to the edges of the two flanges of the right-side air duct section solid model 53) are connected by two mutually perpendicular line segments, forming the boundary line of the right-side air duct inversion template 63 facing away from the inner wall of the cabin (i.e., facing the inner cavity of the cabin). The boundary lines facing away from and facing the inner wall of the cabin together enclose the extruded section of the right-side inversion template, as shown below. Figure 6 (1) Pink irregular cross section shown on the right.

[0037] After the reverse templates of the two side air ducts are stretched, flanges are created at the rear end of the reverse templates of the two side air ducts to connect the left and right side air ducts with the rear panel of the container.

[0038] Step 3.2: Using the inner outer contour of the front step air duct section solid model 51 as a reference, the front air duct inversion template 61 is created by stretching it to the outer side of the left and right air duct inversion templates (referring to the side facing the inner wall of the cabin).

[0039] When the front-end air duct reversal template 61 is created by extrusion, its extruded section is as follows: the inner outer contour of the front-end stepped air duct section solid model 51 (the inner outer contour refers to the section boundary line of the front-end air duct reversal template 61 facing the inner cavity of the cabin) is used as the boundary line facing the inner wall of the cabin in the extruded section of the front-end stepped air duct reversal template 61. The upper edge of this boundary line and the lower edge of this boundary line (corresponding to the edges of the two flanges of the front-end stepped air duct section solid model 51) are connected by two mutually perpendicular line segments, forming the boundary line facing away from the inner wall of the cabin (i.e. facing the inner cavity of the cabin) in the extruded section of the front-end air duct reversal template 61. The boundary lines facing away from and facing the inner wall of the cabin together enclose the extruded section of the front-end air duct reversal template 61, as shown below. Figure 6 (2) The irregular cross-section shown on the right end.

[0040] Step 3.3: Using the outer contour of the front air duct reversal template 61 (outer side refers to the side of the front air duct reversal template 61 facing the inner wall of the container) as a reference, extrude and cut to the inner surfaces of the left and right air duct reversal templates to remove excess surfaces (these excess surfaces refer to the excess surfaces located within the air duct after the left and right air duct reversal templates and the front air duct reversal template 61 intersect), thus completing the creation of the solid reversal template model 6. The completed solid reversal template model 6 is shown below. Figure 7 As shown in (1), Figure 6(4) shows the positional relationship between the created solid inversion template model 6 and the stepped air duct solid model 5.

[0041] Step 4: Convert the solid inverted template model 6 into a sheet metal model.

[0042] like Figure 7 As shown, the specific method is as follows: A shelling operation is performed on the solid inverted template model 5. The shell is used as the driving force to remove redundant faces that do not contact the stepped air duct solid model 5, retaining only the air duct faces. Redundant faces that do not contact the stepped air duct solid model 5 refer to… Figure 7 (1) and Figure 7 (2) shows the bottom surface 611 of the front air duct reversal template, the inner side surface 612 of the front air duct reversal template, the bottom surface 621 of the left air duct reversal template, the inner side surface 622 of the left air duct reversal template, the bottom surface 631 of the right air duct reversal template, and the inner side surface 632 of the right air duct reversal template. (3) shows the air duct surface remaining after removing the 6 redundant surfaces.

[0043] Step 5: Solid inversion template model 6, sheet metal design and 2D unfolding after conversion to sheet metal.

[0044] As shown in Figure 8, in the sheet metal modeling environment, the excess connecting surfaces of the converted sheet metal model that connect to the bulkhead are trimmed, and then arc bends are created at all adjacent surface connections. Finally, the bent sheet metal model is torn using the tearing method in the 3D modeling software. Figure 9 As shown, after tearing, the structure is unfolded in two dimensions to obtain the integrated sheet metal structure of the cabin's stepped air duct. Tearing and unfolding are standard drafting methods; this section mainly describes the specific operations after reversing the template model of this solid object to sheet metal.

[0045] Step 5.1: Trim excess surfaces and create rear flanges for the left and right side air duct sections. Trimming excess connection surfaces in the converted sheet metal model that connect to the bulkhead includes: removing excess surface 7 connecting the front stepped air duct section to the front bulkhead by stretching, such as... Figure 8a As shown, the excess surfaces 8 connecting the rear ends of the left and right air duct sections to the rear bulkhead in the sheet metal model are then removed by stretching, as shown. Figure 8b As shown.

[0046] Step 5.2: Create bends on the sheet metal model after trimming the excess surfaces. For example... Figure 8c As shown, a 0.5mm fillet bend is created at the intersection of all adjacent faces in the model.

[0047] Step 5.3: Tear the bent sheet metal model. This includes the following steps: like Figure 8d As shown, the tearing technique was used to construct four corners (9) at the edges of the left and right air duct sections in the sheet metal model.

[0048] like Figure 8e As shown, the curved surface 10 at the connection between the left and right air duct sections and the front stepped air duct section in the sheet metal model is removed by using curved surface tearing.

[0049] like Figure 8f As shown, the tearing connection is used to complete the tearing of the flange 11 connected to the front panel in the sheet metal model, and to complete the tearing of the flange 12 connected to the rear panel in the sheet metal model.

[0050] like Figure 8g As shown, the tear line on the bottom surface of the left air duct section in the sheet metal model is completed using a sketch tear line. Figure 13 shows the tear line on the bottom surface of the left air duct section in the sheet metal model. Figure 8h As shown, continue to use sketching to complete the tear on the end face of the left air duct section. In the figure, 14 is the tear line on the end face of the left air duct section in the sheet metal model.

[0051] Step 5.4 Two-dimensional unfolding. The torn 3D sheet metal model is unfolded in two dimensions to obtain the following: Figure 9 The diagram shows a two-dimensional machining drawing of the integrated sheet metal structure model. Using this two-dimensional machining drawing of the integrated sheet metal structure, it is possible to perform cutting, bending, and overall welding using CNC equipment, and then install the entire air duct inside the container 4.

[0052] This invention creates a reverse template sheet metal method for modular air ducts. The core of this method is to convert sheet metal by creating a reverse template. By creating the reverse template, two things can be done: first, bending can be added later; second, a connecting flange (i.e., a flange) with the rear cabin plate can be directly created. This ultimately achieves an integrated sheet metal structure design for the air duct, which solves the problem of poor interface consistency caused by segmented bending of the stepped air duct. It also avoids the problems of difficult docking and confined space operation that exist when welding and assembling segmented air ducts inside the modular air duct.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing an integrated sheet metal ventilation duct for a modular cabin, characterized in that, The methods include: Based on the design structure dimensions of the air duct, and taking the three-dimensional model of the container (4) as a reference, an integral stepped air duct solid model (5) is created; the stepped air duct solid model (5) includes a front stepped air duct section solid model (51), a left air duct section solid model (52) and a right air duct section solid model (53). The three air duct solid models are provided with flanges that connect with the container wall of the container (4) on the docking surface. Using the inner outer contour of the side of the solid model of the stepped air duct (5) facing away from the bulkhead of the container (4) as a reference, a solid inversion template model (6) is created. The solid inversion template model (6) is set to correspond with the three-section air duct solid model. Its side facing the solid model of the stepped air duct (5) is completely consistent with the inner outer contour of the solid model of the stepped air duct (5). Its side facing away from the solid model of the stepped air duct (5) is the vertical intersecting plane created by the flange edges on both sides of the corresponding solid model along the vertical and horizontal directions respectively. The solid inversion template model (6) completely covers the solid model of the stepped air duct (5). The solid inverted template model (6) is converted into a sheet metal model. Specifically, the solid inverted template model (6) is shelled to remove the redundant surfaces that do not contact the solid model (5) of the stepped air duct. In the sheet metal modeling environment, the excess connecting surfaces that connect to the bulkhead in the converted sheet metal model are repaired, and then arc bends are created at all adjacent surface connections. Then, the sheet metal model after bending is torn using the tearing method in the 3D modeling software, and then unfolded in two dimensions to obtain the integrated sheet metal structure of the cabin step air duct.

2. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 1, characterized in that, The methods for creating a solid model of a stepped air duct (5) include: Using the inner wall of the front panel of the container as the reference plane, and according to the cross-sectional shape of the right air duct (1), the model is created by stretching the length to the inner side of the rear panel of the container, thus completing the creation of the solid model (53) of the right air duct section. Using the yz plane (15) as the reference plane, according to the cross-sectional shape of the front step air duct (2), the right half of the front step air duct section solid model (53) is created by stretching the length to the right side air duct section solid model (53) and fitting it with the inner side, thus completing the creation of the right half of the front step air duct section solid model (51); the yz plane (15) is a plane that is perpendicular to the front step air duct section solid model (51) and passes through the center of the front step air duct section solid model (51); Select the right half of the existing right air duct section solid model (53) and the front step air duct section solid model (51), and mirror the left air duct section solid model (52) and the front step air duct section solid model (51) with the yz plane (15) as the symmetry plane to complete the creation of the step air duct solid model (5).

3. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 1, characterized in that, The solid inverted template model (6) includes a left air duct inverted template (62), a right air duct inverted template (63), and a front air duct inverted template (61); the method for creating the solid inverted template model (6) includes: Using the inner outer contour of the solid model (52) of the left air duct section as a reference and the inner outer contour of the solid model (53) of the right air duct section as a reference, the left air duct inversion template (62) and the right air duct inversion template (63) are created by extrusion, and the extrusion length is the same as that of the solid models of the two air ducts. Then, taking the inner outer contour of the front step air duct section solid model (51) as a reference, the front air duct inversion template (61) is created by stretching it to the outer side of the left and right air duct inversion templates. Then, using the outer contour of the front air duct inversion template (61) as a reference, stretch and cut to the inner side of the left and right air duct inversion templates to remove excess surfaces and complete the creation of the solid inversion template model (6).

4. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 3, characterized in that, When the left air duct inversion template (62) is created by extrusion, its extrusion section is: the inner outer contour of the solid model (52) of the left air duct section is used as the boundary line facing the container (4) in the extrusion section of the left air duct inversion template (62). The upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the container (4) in the extrusion section of the left air duct inversion template (62), which together form the extrusion section of the left inversion template.

5. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 3, characterized in that, When the right air duct inversion template (63) is created by extrusion, its extrusion section is: the inner outer contour of the solid model (53) of the right air duct section is used as the boundary line facing the cabin in the extrusion section of the right air duct inversion template (63). The upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the cabin in the extrusion section of the right air duct inversion template (63), which together form the extrusion section of the right inversion template.

6. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 3, characterized in that, When the front air duct reversal template (61) is created by extrusion, its extrusion section is: the inner outer contour of the front step air duct section solid model (51) is used as the boundary line facing the cabin in the extrusion section of the front step air duct reversal template (61). The upper edge of the boundary line and the lower edge of the boundary line are connected by two mutually perpendicular line segments to form the boundary line facing away from the cabin in the extrusion section of the front air duct reversal template (61), which together form the extrusion section of the front air duct reversal template (61).

7. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 1, characterized in that, The excess connection surfaces in the modified sheet metal model that are connected to the bulkhead include: removing the excess surface connecting the front step air duct section to the front bulkhead by stretching (7); and removing the excess surface connecting the rear end of the left and right air duct sections to the rear bulkhead by stretching (8).

8. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 1, characterized in that, The steps of the tearing method include: The four corners (9) of the left and right air duct sections in the sheet metal model were constructed by edge tearing. The curved surface (10) at the connection between the left and right side air duct sections and the front step air duct section in the sheet metal model was removed by using curved surface tearing. The tearing connection is used to complete the tearing of the flange (11) connected to the front panel in the sheet metal model, and the tearing of the flange (12) connected to the rear panel in the sheet metal model is also completed. Use sketch tearing to complete the tearing on the bottom surface of the left air duct section in the sheet metal model; continue using sketch tearing to complete the tearing on the end surface of the left air duct section.

9. The integrated sheet metal design method for the modular cabin stepped air duct according to claim 1, characterized in that, The three-dimensional model construction method of the container (4) is as follows: if the container is a right-angle container, stretch it with the front or rear shape of the container as the cross section, then shell it, and then remove the rear panel; if the container is a single-corner container, stretch it with the front or rear shape of the container as the cross section, then chamfer it to form a single corner, then shell it, and then remove the rear panel.

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