Hollow structure and method of manufacturing hollow structure

Abstract

To provide a hollow structure that can easily form a cavity part, and is low-cost and high in degree of design freedom, and a method of manufacturing the hollow structure.SOLUTION: A hollow structure 100 comprises a lower plate 11, an upper plate 13, and a cylindrical hollow extruded material 15. One extrusion-directional end face of the hollow extruded material 15 abuts on the lower plate 11 more on an inner peripheral side than an outer peripheral surface of the lower plate 11, and the other extrusion-directional end face of the hollow extruded material 15 abuts on the upper plate 13 more on an inner peripheral side than an outer peripheral surface of the hollow extruded material 15. A lower step surface is formed between the outer peripheral surface of the lower plate 11 and the outer peripheral surface of the hollow extruded material 15, and a lower joint part 23 is formed at a corner part where the lower step surface and the outer peripheral surface of the hollow extruded material 15 cross each other. An upper step surface along the other end surface of the hollow extruded material 15 is formed between the outer peripheral surface of the hollow extruded material 15 and the outer peripheral surface of the upper plate 13, and an upper joint part 25 is formed at a corner part where the upper step surface and the outer peripheral surface of the upper plate 13 cross each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hollow structure and a method for manufacturing a hollow structure. [Background technology]

[0002] Conventionally, the manufacture of hollow structures having internal cavities has often been impossible using casting or injection molding due to factors such as draft angles, etc. For this reason, hollow structures are sometimes manufactured by a method such as forming blind holes in a solid block by machining such as drilling, and then sealing the openings of the formed blind holes. Patent Document 1 also discloses a cooling device equipped with a semiconductor module, which has an upper lid and a lower storage section. The lower storage section is a box-shaped container with a bottom, and has an inlet at one end and an outlet at the other end. The opening of the lower storage section is sealed by brazing the upper lid. This allows a refrigerant to circulate through the inlet, the flow path between the lower storage section and the upper lid, and the outlet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6870253 Summary of the Invention [Problem to be solved by the invention]

[0004] However, forming a cavity by machining requires the laborious process of attaching and detaching the base material to a jig, as well as the need to seal the drilled opening, resulting in low productivity and high processing costs. Furthermore, forming the cavity by cutting out increases material costs, increases processing time, and limits design freedom for the shape of the cavity. Furthermore, forming a cavity by brazing a lid and a housing requires the lid and housing to be pressed together at a predetermined temperature, which requires these materials to be passed through a heat treatment furnace for brazing, making the process complicated and lengthening the processing time.

[0005] Therefore, an object of the present invention is to provide a hollow structure and a method for manufacturing the hollow structure, which can easily form a cavity with high productivity, at low cost, and with a high degree of freedom in design. [Means for solving the problem]

[0006] The present invention comprises the following configurations. (1) A lower plate; an upper plate disposed opposite the lower plate; a cylindrical hollow extrusion material disposed between the lower plate and the upper plate, with the direction from the lower plate toward the upper plate being the extrusion direction; Equipped with one end face of the hollow extrusion material in the extrusion direction abuts against the lower plate at a position more inward than the outer circumferential surface of the lower plate, and the other end face of the hollow extrusion material in the extrusion direction abuts against the upper plate at a position more inward than the outer circumferential surface of the hollow extrusion material; a lower step surface is formed between the outer peripheral surface of the lower plate and the outer peripheral surface of the hollow extrusion material, the lower step surface being aligned with the upper surface of the lower plate; a lower joint portion that joins the lower plate and the hollow extrusion material is formed at a corner where the lower step surface and the outer circumferential surface of the hollow extrusion material intersect, an upper step surface is formed between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, the upper step surface being along the other end surface of the hollow extrusion material; An upper joint portion that joins the hollow extrusion material and the upper plate is formed at a corner where the upper step surface and the outer peripheral surface of the upper plate intersect. hollow structure. (2) preparing a lower plate, an upper plate, and a cylindrical hollow extrusion material; one end surface of the hollow extrusion in the extrusion direction is brought into contact with the lower plate at a position inside the outer peripheral surface of the lower plate; the other end surface of the hollow extrusion material in the extrusion direction is brought into contact with the upper plate at a position inside the outer circumferential surface of the hollow extrusion material; the lower plate and the hollow extrusion material are joined at a corner where a lower step surface along the lower plate between an outer peripheral surface of the lower plate and an outer peripheral surface of the hollow extrusion material intersects with the outer peripheral surface of the hollow extrusion material; The hollow extrusion material and the upper plate are joined at a corner between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, where an upper step surface along an end face of the hollow extrusion material on the upper plate side intersects with the outer peripheral surface of the upper plate. A method for manufacturing a hollow structure. [Effects of the Invention]

[0007] According to the present invention, a hollow portion can be easily formed with high productivity, and a hollow structure with high design freedom can be obtained at low cost. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of the appearance of the hollow structure. [Figure 2] FIG. 2 is an exploded perspective view of the hollow structure shown in FIG. [Figure 3] FIG. 3 is a plan view of the hollow structure shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view of part A shown in FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view of part B shown in FIG. [Figure 7] FIG. 7 is an explanatory diagram that schematically shows the state of laser welding with the addition of filler metal. [Figure 8] FIG. 8 is a schematic cross-sectional view of a sealed joint. [Figure 9] FIG. 9 is a perspective view of a hollow structure shown as a reference example, in which a flow path is formed by machining a block and partially closing holes. [Figure 10] FIG. 10 is a plan view of a hollow structure in which a bracket is provided on the lower plate. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The hollow structure according to the present invention may be any structure in which a cavity is formed using a hollow extruded material, and the cross-sectional shape perpendicular to the extrusion direction of the hollow extruded material, the length in the extrusion direction, and other shapes can be freely set depending on the intended use, etc. Here, a hollow structure having a flow path connecting the inside and outside of the cavity, with an inlet and an outlet of the flow path, will be described as an example.

[0010] <Configuration of hollow structure> Fig. 1 is an external perspective view of a hollow structure 100. Fig. 2 is an exploded perspective view of the hollow structure 100 shown in Fig. 1. The hollow structure 100 shown in Fig. 1 has a lower plate 11, an upper plate 13 arranged opposite the lower plate 11, and a hollow extrusion material 15 arranged between the lower plate 11 and the upper plate 13. The hollow extrusion material 15 is a cylindrical body arranged with the direction from the lower plate 11 toward the upper plate 13 as the extrusion direction ED. Furthermore, as shown in Fig. 2, openings 13a and 13b are formed in two places on the plate surface of the upper plate 13, and a pipe member 17A is connected to one opening hole 13a, and a pipe member 17B is connected to the other opening hole 13b.

[0011] Fig. 3 is a plan view of the hollow structure 100 shown in Fig. 1. Fig. 4 is a cross-sectional view taken along line IV-IVI shown in Fig. 1. As shown in Figs. 3 and 4, the outer peripheral surfaces of the pipe members 17A and 17B fit into the inner peripheral surfaces of the opening holes 13a and 13b of the upper plate 13. A cavity 19 is formed inside the hollow extrusion material 15, and the cavity 19 communicates with the outside through the inner spaces 21A and 21B of the pipe members 17A and 17B.

[0012] The outer peripheral edge of the hollow extrusion material 15 is located more inward than the outer peripheral edge of the lower plate 11. A stepped surface, which will be described later, is formed around the entire circumference between the outer peripheral edge of the lower plate 11 and the outer peripheral surface of the hollow extrusion material 15. The outer peripheral edge of the upper plate 13 is located more inward than the outer peripheral edge of the hollow extrusion material 15. A stepped surface, which will be described later, is formed around the entire circumference between the outer peripheral edge of the top surface of the hollow extrusion material 15 and the outer peripheral surface of the upper plate 13.

[0013] Fig. 5 is an enlarged cross-sectional view of portion A shown in Fig. 4. One end surface 15a of the hollow extrusion material 15 below in the extrusion direction ED abuts against the lower plate 11 on the inner side of the outer peripheral surface 11a of the lower plate 11. A lower step surface 11c along the upper surface 11b of the lower plate 11 is formed between the outer peripheral surface 11a of the lower plate 11 and the outer peripheral surface 15b of the hollow extrusion material 15. A lower joint portion 23 that joins the lower plate 11 and the hollow extrusion material 15 is formed at the corner where the lower step surface 11c and the outer peripheral surface 15b of the hollow extrusion material 15 intersect.

[0014] Fig. 6 is an enlarged cross-sectional view of portion B shown in Fig. 4. The upper plate 13 abuts against the other end surface 15c of the hollow extrusion material 15 upward in the extrusion direction, on the inner side of the outer peripheral surface 15b of the hollow extrusion material 15. An upper step surface 15d is formed between the outer peripheral surface 15b of the hollow extrusion material 15 and the outer peripheral surface 13c of the upper plate 13, along the other end surface 15c of the hollow extrusion material 15. An upper joint portion 25 that joins the hollow extrusion material 15 and the upper plate 13 is formed at the corner where the upper step surface 15d and the outer peripheral surface 13c of the upper plate 13 intersect.

[0015] Furthermore, outer peripheral surface 17a of pipe member 17A inserted into opening hole 13a of upper plate 13 is positioned more inward than outer peripheral surface 13c of upper plate 13, and upper plate step surface 13e is formed between outer peripheral surface 13c of upper plate 13 and outer peripheral surface 17a of pipe member 17A, along upper surface 13d of upper plate 13. Then, upper plate joint portion 27 that joins upper plate 13 and pipe member 17A is formed at the corner where upper plate step surface 13e and outer peripheral surface 17a of pipe member 17A intersect.

[0016] Similarly, an upper plate joint 27 that joins the upper plate 13 and the pipe member 17B is formed at the corner where the outer peripheral surface 17a of the pipe member 17B and the upper surface of the upper plate 13 intersect (see FIG. 4).

[0017] The lower joint 23 and upper joint 25 join the lower plate 11, the hollow extrusion 15, and the upper plate 13 together, forming a hollow portion 17 inside the hollow extrusion 15. Furthermore, the upper plate joint 27 joins the upper plate 13 and the pipe members 17A, 17B, connecting the inner spaces 21A, 21B of the pipe members 17A, 17B to the hollow portion 19. In this way, the hollow portion 19 formed by being surrounded by the lower plate 11, the upper plate 13, and the hollow extrusion 15 can form a flow path that communicates between the inside and outside of the hollow portion 19, with the inner spaces 21A, 21B of the pipe members 17A, 17B serving as an inlet and an outlet.

[0018] The cavity 19 and the inner spaces 21A, 21B are stably airtight and watertight from the outside by the joining of the members by the lower joint 23, the upper joint 25, and the upper plate joint 27.

[0019] When the hollow portion 19 of the hollow structure 100 having the above-described configuration is used as a gas flow path, it can be applied to piping fixtures for city gas, LP gas, biogas, hydrogen gas, medical gas, etc., thereby reducing equipment costs. Furthermore, when the hollow portion 19 is used as a coolant flow path, a heat sink with high degree of freedom in shape can be obtained, which allows for improved heat transfer efficiency and reduced costs. Furthermore, when this hollow structure 100 is applied to other uses, it can also reduce costs.

[0020] <Materials for each component> The lower plate 11, the upper plate 13, the hollow extrusion material 15, and the pipe members 17A and 17B are made of, for example, a wrought material made of aluminum or an aluminum alloy (hereinafter also referred to as aluminum material). The use of a wrought material allows for a configuration with superior dimensional accuracy compared to a cast product. Furthermore, the use of aluminum material allows for a configuration with reduced weight and excellent thermal conductivity. The hollow extrusion material 15 is a tubular extrusion material with a closed cross section perpendicular to the extrusion direction, and may be made of, for example, a 2000 series, 5000 series, 6000 series, or 7000 series aluminum alloy. The thickness of the upper plate 13 is preferably 1 mm or more and 10 mm or less, considering its strength and the fact that the opening holes 13a and 13b are drilled by pressing.

[0021] Furthermore, when the lower plate 11, the upper plate 13, the hollow extrusion member 15, and the pipe members 17A and 17B are made of aluminum, it is preferable to anodize the surfaces of these members after welding or fusion bonding, which can improve the corrosion resistance and wear resistance of the hollow structure 100.

[0022] <Construction method for joints> The lower joint 23, upper joint 25, and upper plate joint 27 are each formed by sealed joining with a filler metal. Examples of sealed joining include laser welding (laser metal deposition-wire: LMD-W), which melts and solidifies a filler metal, plasma welding, and brazing such as laser brazing. They can also be formed by metal additive manufacturing techniques such as wire and arc additive manufacturing (WAAM), including tungsten inert gas (TIG) welding and metal inert gas (MIG) welding. Laser welding and laser brazing are particularly preferred because they can form thin weld beads or welded portions and can provide stable joining with high productivity through simple processes, even when the shape of the joint is complex.

[0023] 7 is an explanatory diagram showing a schematic diagram of laser welding with filler metal addition. In this sealed joining, an aluminum filler metal W fed by a feeder is protruded from the tip of a torch 31, and a laser beam LB is irradiated onto the protruding aluminum filler metal W. As a result, a bead B is formed by the molten aluminum filler metal W along the corners of the aforementioned members, joining the members together.

[0024] This joining is performed along the entire periphery of each corner of the lower step surface 11c, upper step surface 15d, and upper plate step surface 13e, which are exposed when the lower plate 11, hollow extrusion 15, upper plate 13, and pipe members 17A and 17B are stacked in this order. This sealed joining makes it easy to obtain a joining form with excellent aesthetics, and also enables high-speed welding, thereby improving production efficiency. In addition, since this welding applies a reinforcement that suppresses melting of the base material, stable welding quality can be ensured.

[0025] Figure 8 is a schematic cross-sectional view of a sealed joint. It is preferable that the horizontal leg length L1 and the vertical leg length L2 of the joint are equal. The recommended upper limit of the leg length varies depending on the diameter of the filler metal and the welding method, as shown in Table 1, but is preferably 1 mm or more and 10 mm or less. Furthermore, the leg length is preferably 10 mm or less when the diameter of the filler metal is 1.6 mm, preferably 8 mm or less when the diameter of the filler metal is 1.0 to 1.2 mm, and preferably 5 mm or less when the diameter of the filler metal is 0.8 mm. By keeping the leg length within the above range, the required joint strength can be obtained.

[0026] [Table 1]

[0027] <Comparison with reference example> 9 is a perspective view of a hollow structure 110 shown as a reference example, showing a flow path 35 formed by machining (cutting) a block 33 and partially closing (sealing) the holes. The block 33 of this reference example is a U-shaped solid body having a base 37 extending in one direction and a pair of protrusions 39A, 39B provided at both longitudinal ends of the base 37. The base 37 is provided with a drilled hole 41 that serves as a stop hole along the longitudinal direction. The opening of the drilled hole 41 is sealed by welding a sealing member 43. The pair of protrusions 39A, 39B have connection holes 45A, 45B formed from their respective ends toward the drilled hole 41 in the base 37.

[0028] In the hollow structure 110 configured as described above, the flow path 35 is formed by the drilled hole 41 and the connecting holes 45A and 45B. This requires a process of machining each hole and a welding process of closing the opening of the drilled hole 41, which complicates the process of forming the flow path and increases the manufacturing cost.

[0029] On the other hand, according to the hollow structure 100 shown in Fig. 4, a closed space (flow path) is formed by stacking multiple members in a stepped manner from the bottom up, and forming joints on the step surfaces of each step. In this case, a space such as a flow path can be easily formed by moving a torch 31 (Fig. 7) relative to the workpiece (multiple members) along the step surfaces and joining the members by welding or fusing along the corners formed on the step surfaces. In other words, the desired space can be formed simply by welding the step surfaces created by stacking multiple members, without the need to firmly fix the workpiece with a jig or to perform complicated machining that requires the disposal of cutting oil and chips.

[0030] Furthermore, because the stepped surfaces of each step are all exposed and facing upward, when the torch 31 and the workpiece are moved relative to each other to weld, the position of the workpiece can be maintained constant, eliminating the need to change the position using a positioner or to significantly change the position of the torch 31. In this way, welding can be performed easily without complicating the welding rod operation or using a dedicated jig. The same effects as those described above can also be achieved in deposition, not just welding.

[0031] <Other examples of hollow structure shapes> The shape of the hollow extrusion material 15 can be changed in various ways, such as changing from a simple tubular shape to a more complex shape, or tilting the end face of the hollow extrusion material 15 from a direction perpendicular to the extrusion direction, etc. Furthermore, the pipe members 17A, 17B are not limited to a configuration in which they protrude in the extrusion direction ED of the hollow extrusion material 15, but may also be a configuration in which they protrude in a direction tilted from the extrusion direction ED, or a configuration in which they protrude in different directions from each other, and a configuration in which the number of pipe members is increased or decreased.

[0032] Alternatively, openings may be provided in the lower plate 11, and the pipe members 17A and 17B may be connected to the openings, so that the internal spaces 21A and 21B of the pipe members 17A and 17B communicate with the hollow portion 19. Similarly, openings may be provided in the outer surface 15b of the hollow extrusion material 15, and the pipe members 17A and 17B may be connected to the openings, so that the internal spaces 21A and 21B of the pipe members 17A and 17B communicate with the hollow portion 19. Alternatively, instead of providing the pipe members 17A and 17B, connecting members such as well-known connectors may be attached to appropriate locations on the upper plate 13 or the like and used as inlets and outlets. Furthermore, the above-mentioned connection configurations may be combined as appropriate.

[0033] 10 is a plan view of a hollow structure 100A in which a bracket is provided on the lower plate 11A. A bracket 47 for connection to another member may be formed on the lower plate 11A. For example, the hollow structure 100A can be fixed to another member by connecting it to the other member through a fastening member (not shown) such as a screw or rivet that penetrates the bracket 47 in the thickness direction and passes through an attachment hole 49 formed therein. The bracket 47 described above is not limited to the lower plate 11A, and one or more brackets 47 may be provided on at least one part of the upper plate 13 or the hollow extrusion member 15. As such, this configuration improves the degree of freedom in designing the shape without complicating the manufacturing process of the hollow structure.

[0034] The present invention is not limited to the above-described embodiments, and it is also intended that the various components of the embodiments be combined with one another, and that modifications and applications be made by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0035] As described above, the present specification discloses the following: (1) A lower plate; an upper plate disposed opposite the lower plate; a cylindrical hollow extrusion material disposed between the lower plate and the upper plate, with the direction from the lower plate toward the upper plate being the extrusion direction; Equipped with one end face of the hollow extrusion material in the extrusion direction abuts against the lower plate at a position more inward than the outer circumferential surface of the lower plate, and the other end face of the hollow extrusion material in the extrusion direction abuts against the upper plate at a position more inward than the outer circumferential surface of the hollow extrusion material; a lower step surface is formed between the outer peripheral surface of the lower plate and the outer peripheral surface of the hollow extrusion material, the lower step surface being aligned with the upper surface of the lower plate; a lower joint portion that joins the lower plate and the hollow extrusion material is formed at a corner where the lower step surface and the outer circumferential surface of the hollow extrusion material intersect, an upper step surface is formed between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, the upper step surface being along the other end surface of the hollow extrusion material; An upper joint portion that joins the hollow extrusion material and the upper plate is formed at a corner where the upper step surface and the outer peripheral surface of the upper plate intersect. hollow structure. According to this hollow structure, a lower plate, a hollow extrusion, and an upper plate are stacked in this order, and the lower plate and the hollow extrusion are joined at a lower joint formed at a corner between the lower step surface and the outer peripheral surface of the hollow extrusion. Also, the hollow extrusion and the upper plate are joined at an upper joint formed at a corner between the upper step surface and the outer peripheral surface of the upper plate. This makes it possible to form a hollow structure in which the inside of the hollow extrusion is sandwiched between the lower plate and the upper plate to form a cavity, with a structure that minimizes the need for machining such as cutting.

[0036] (2) A hollow structure as described in (1), in which a hollow portion formed by being surrounded by the lower plate, the upper plate, and the hollow extrusion material has an inlet and an outlet of a flow path connecting the inside and outside of the hollow portion formed in at least one of the lower plate, the upper plate, and the hollow extrusion material. According to this hollow structure, by having an inlet and an outlet communicating with the cavity, for example, a fluid can be made to flow into and out of the cavity, thereby causing the fluid to flow inside the hollow structure.

[0037] (3) A hollow structure according to (1) or (2), wherein at least one of the lower joint and the upper joint is a sealed joint to which a filler material is added. With this hollow structure, each component is joined by a sealing joint containing an additive, and the spaces between the lower plate and the hollow extrusion material, and between the hollow extrusion material and the upper plate, can be sealed with high welding quality and an aesthetically pleasing form.

[0038] (4) A hollow structure according to any one of (1) to (3), wherein the leg lengths of the upper joint and the lower joint are 1 mm or more and 10 mm or less. This hollow structure provides high bonding strength with beads having a sufficient leg length.

[0039] (5) A hollow structure according to any one of (1) to (4), wherein an attachment hole is formed through the thickness direction in at least one of the lower plate, the upper plate, and the hollow extrusion material. According to this hollow structure, the mounting holes can be used to easily fix the hollow structure to other members.

[0040] (6) The hollow structure according to any one of (1) to (5), wherein the lower plate, the upper plate, and the hollow extrusion material are made of aluminum or an aluminum alloy. This hollow structure allows for a lightweight configuration.

[0041] (7) preparing a lower plate, an upper plate, and a cylindrical hollow extrusion material; one end surface of the hollow extrusion in the extrusion direction is brought into contact with the lower plate at a position inner than the outer circumferential surface of the lower plate; the other end surface of the hollow extrusion material in the extrusion direction is brought into contact with the upper plate at a position inner than the outer circumferential surface of the hollow extrusion material; the lower plate and the hollow extrusion material are joined at a corner where a lower step surface along the lower plate between an outer peripheral surface of the lower plate and an outer peripheral surface of the hollow extrusion material intersects with the outer peripheral surface of the hollow extrusion material; The hollow extrusion material and the upper plate are joined at a corner between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, where an upper step surface along an end face of the hollow extrusion material on the upper plate side intersects with the outer peripheral surface of the upper plate. A method for manufacturing a hollow structure. According to this method for manufacturing a hollow structure, a lower plate, a hollow extrusion, and an upper plate are stacked in this order, and the lower plate and the hollow extrusion are joined at a corner between the lower step surface and the outer peripheral surface of the hollow extrusion. Also, the hollow extrusion and the upper plate are joined at a corner between the upper step surface and the outer peripheral surface of the upper plate. This makes it possible to form a hollow structure in which the inside of the hollow extrusion is sandwiched between the lower plate and the upper plate to form a cavity, with a structure that minimizes the need for machining such as cutting.

[0042] (8) A method for manufacturing a hollow structure according to (7), wherein at least one of the joining of the lower plate and the hollow extrusion material and the joining of the hollow extrusion material and the upper plate is performed by a sealed joining using a filler material. According to this manufacturing method for a hollow structure, each component is joined by a sealing joint containing an additive, and the space between the lower plate and the hollow extrusion material, and the space between the hollow extrusion material and the upper plate can be sealed with high welding quality and an aesthetically pleasing form.

[0043] (9) The method for manufacturing a hollow structure according to (8), wherein the sealing joint is either laser welding or laser brazing, which melts and solidifies a filler material. According to this method for manufacturing a hollow structural body, even if the shape of the joint is complicated, stable joining with high joining strength can be achieved.

[0044] (10) The method for manufacturing a hollow structure according to any one of (7) to (9), wherein the lower plate, the upper plate, and the hollow extrusion material are made of aluminum or an aluminum alloy. This method of manufacturing a hollow structure allows for a lightweight structure. [Explanation of symbols]

[0045] 11,11A Lower plate 11a Outer surface 11b Top surface 11c Lower step surface 13 Upper Plate 13a,13b opening hole 13c Outer surface 13d top surface 13e Upper plate step surface 15 Hollow extrusion material 15a One end face 15b Outer surface 15c Other end surface 15d Upper step surface 17A, 17B Pipe members 17a Outer surface 19 Cavity 21A,21B Inner space 23 Lower joint 25 Upper junction 27 Upper plate joint 31 Torch 47 Bracket 49 Mounting holes 100 hollow structure B bead LB laser light W aluminum filler metal

Claims

1. The bottom plate and an upper plate disposed opposite the lower plate; a cylindrical hollow extrusion material disposed between the lower plate and the upper plate, with the direction from the lower plate toward the upper plate being the extrusion direction; Equipped with one end face of the hollow extrusion material in the extrusion direction abuts against the lower plate at a position more inward than the outer circumferential surface of the lower plate, and the other end face of the hollow extrusion material in the extrusion direction abuts against the upper plate at a position more inward than the outer circumferential surface of the hollow extrusion material; a lower step surface is formed between the outer peripheral surface of the lower plate and the outer peripheral surface of the hollow extrusion material, the lower step surface being aligned with the upper surface of the lower plate; a lower joint portion that joins the lower plate and the hollow extrusion material is formed at a corner where the lower step surface and the outer circumferential surface of the hollow extrusion material intersect, an upper step surface is formed between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, the upper step surface being along the other end surface of the hollow extrusion material; An upper joint portion that joins the hollow extrusion material and the upper plate is formed at a corner where the upper step surface and the outer peripheral surface of the upper plate intersect. hollow structure.

2. a cavity portion surrounded by the lower plate, the upper plate, and the hollow extrusion material, wherein an inlet and an outlet of a flow path communicating the inside and outside of the cavity portion are formed in at least one of the lower plate, the upper plate, and the hollow extrusion material; The hollow structure according to claim 1 .

3. At least one of the lower joint and the upper joint is a sealed joint to which a filler material is added. The hollow structure according to claim 1 .

4. The leg lengths of the upper joint and the lower joint are 1 mm or more and 4 mm or less. The hollow structure according to claim 1 .

5. At least one of the lower plate, the upper plate, and the hollow extrusion material has an attachment hole formed therethrough in the thickness direction. The hollow structure according to claim 1 .

6. The lower plate, the upper plate, and the hollow extrusion material are made of aluminum or an aluminum alloy. The hollow structure according to any one of claims 1 to 5.

7. A lower plate, an upper plate, and a cylindrical hollow extrusion material are prepared; one end surface of the hollow extrusion in the extrusion direction is brought into contact with the lower plate at a position inside the outer peripheral surface of the lower plate; the other end surface of the hollow extrusion material in the extrusion direction is brought into contact with the upper plate at a position inside the outer circumferential surface of the hollow extrusion material; the lower plate and the hollow extrusion material are joined at a corner where a lower step surface along the lower plate between an outer peripheral surface of the lower plate and an outer peripheral surface of the hollow extrusion material intersects with the outer peripheral surface of the hollow extrusion material; The hollow extrusion material and the upper plate are joined at a corner between the outer peripheral surface of the hollow extrusion material and the outer peripheral surface of the upper plate, where an upper step surface along an end face of the hollow extrusion material on the upper plate side intersects with the outer peripheral surface of the upper plate. A method for manufacturing a hollow structure.

8. At least one of joining the lower plate and the hollow extrusion material and joining the hollow extrusion material and the upper plate is performed by sealed joining with added filler material. The method for manufacturing the hollow structure according to claim 7 .

9. The sealing joint is either laser welding or laser brazing, in which a filler material is melted and solidified. The method for manufacturing the hollow structure according to claim 8 .

10. The lower plate, the upper plate, and the hollow extrusion material are made of aluminum or an aluminum alloy. A method for manufacturing a hollow structural body according to any one of claims 7 to 9.

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