Aluminum profile connecting structure

Abstract

To provide a connection structure of an aluminum mold material that can prevent an aluminum mold material to be disposed in the vicinity of a carbon fiber-reinforced resin from corroding.SOLUTION: A connection structure 1 of an aluminum mold material includes: a pair of aluminum mold materials 31 including a hollow part 30, mutually abutting on and connected to each other; a sleeve 4 provided to a connection part 32 of the pair of aluminum mold materials 31 and inserted into the hollow part 30; and a carbon fiber-reinforced resin member 5 disposed at a surface of the sleeve 4. Inner peripheral surfaces 311a, 312a of the pair of aluminum mold materials 31 in the connection part 32 are provided with an alumite film 33 or a boehmite film 34.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a connecting structure for aluminum profiles.

Background Art

[0002] Conventionally, in various structures, members, etc., it is known to stack and arrange metal parts such as aluminum and carbon fiber reinforced resin (CFRP). Since carbon contained in the carbon fiber reinforced resin is conductive, in order to prevent corrosion of the aluminum member in contact with the carbon fiber reinforced resin, it has been proposed to arrange a non-conductive sheet such as a glass fiber reinforced resin between the aluminum member and the carbon fiber reinforced resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Providing other members such as glass fiber reinforced resin increases the manufacturing cost and requires space for other members. When connecting aluminum profiles, it is desirable to prevent corrosion of the aluminum profiles arranged close to the carbon fiber reinforced resin without providing other members.

Means for Solving the Problems

[0005] This disclosure relates to a connecting structure for aluminum profiles, comprising a pair of aluminum profiles having hollow portions and abutted and connected to each other, a sleeve provided at the connecting portion of the pair of aluminum profiles and inserted into the hollow portion, and a carbon fiber reinforced resin member disposed on the surface of the sleeve, wherein an alumite film or a boehmite film is provided on the inner peripheral surfaces of the pair of aluminum profiles at the connecting portion.

Brief Description of the Drawings

[0006] [Figure 1] This is a diagram showing the arch of this embodiment. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Modes for carrying out the invention]

[0007] Embodiments of this disclosure will now be described in detail with reference to the drawings. As shown in Figure 1, the arch 10 of this embodiment is a framework for an aluminum decorative member used for decorating a space. The arch 10 includes an aluminum profile connecting structure 1 formed by butting a pair of aluminum profiles together, and also has support columns 2, beams 3, and sleeves 4.

[0008] The support columns 2 are positioned opposite each other on one side and the other side in the left-right direction when viewed from the front of the arch 10. The support columns 2 are installed so as to extend vertically from the ground or other mounting surface. The support columns 2 are long aluminum profiles with a hollow structure that is hollow inside and has a roughly rectangular cross-section. The height dimension of the support columns 2 is not limited, but for example, they are about 2.5m long.

[0009] The girder 3 connects to the upper ends of the support columns 2 and is positioned to extend in the left-right direction in a front view of the arch 10. The length of the girder 3 is not limited, but it is, for example, about 10m long. The girder 3 is constructed by connecting a pair of girder bodies 31, which are aluminum profiles, and has a girder body 31, a connecting part 32, and a sleeve 4.

[0010] The girder body 31 is a long aluminum profile with a hollow structure that is hollow inside and has a roughly rectangular cross-section. As shown in Figure 1, the girder body 31 is a component that forms one girder 3 by connecting two girder bodies 31, and the cross-sectional shape of each girder body 31 is the same. The lengths of the connected girder bodies 31 may be different and are not limited, but for example they may be 4m and 6m. As shown in Figure 2, the girder body 31 has a hollow section 30, a girder upper section 311, a girder lower section 312, and a pair of girder side sections 313.

[0011] The hollow section 30 is the internal space of the girder body 31, extending from one end to the other in the longitudinal direction of the girder body 31. The girder upper surface 311 is a flat surface that is approximately rectangular in plan view. The width of the girder upper surface 311 in the short direction is, for example, about 15 cm. The girder lower surface 312 is a flat surface that is approximately rectangular in plan view, and is located below the girder upper surface 311. The width of the girder lower surface 312 in the short direction is, for example, about 15 cm. The girder side surface 313 is a flat surface that connects the girder upper surface 311 and the girder lower surface 312. As shown in Figure 2, the girder side surface 313 extends downward from the end of the girder upper surface 311, over the end of the girder lower surface 312, and is positioned to protrude downward from the lower end of the girder lower surface 312 in cross-sectional view. The width of the girder side surface 313 in the short direction is, for example, about 15 cm. The inner circumferential surfaces 311a and 312a of the upper girder portion 311 and the lower girder portion 312, that is, the surfaces facing the hollow portion 30, are provided with an anodized coating 33 or a boehmite coating 34 formed by electrode treatment or hydrothermal treatment.

[0012] The anodized coating 33 is a coating formed on the surface of aluminum by immersing the aluminum profile constituting the girder body 31 in an electrolyte solution and passing an electric current through the electrolyte solution. The boehmite coating 34 is a coating formed on the surface of aluminum by immersing the aluminum profile constituting the girder body 31 in hot water at 75 degrees Celsius or higher. The anodized coating 33 or the boehmite coating 34 may be formed on the entire inner circumferential surface of the hollow portion 30, but it is sufficient if it is formed on the inner circumferential surface of the portion where a pair of girder bodies 31 are butted together and connected, that is, on the inner circumferential surface of the girder body 31 in the connecting portion 32 described below.

[0013] The connecting portion 32 is the part where the ends of one girder body 31a and the other girder body 31b are connected. The connecting portion 32 refers to the area where the ends of adjacent girder bodies 31a and 31b are abutted together, and the sleeve 4, which will be described below, is inserted through the hollow portion 30 inside the girder bodies 31a and 31b.

[0014] Sleeve 4 is provided on the connecting portion 32 and is positioned by being inserted through the hollow portion 30 of the two girder bodies 31a and 31b. Sleeve 4 is positioned to increase the strength of the portion where the girder bodies 31 are connected to each other. Sleeve 4 is a long aluminum profile with a hollow structure that is hollow inside and has a roughly rectangular cross-section. The length of sleeve 4 is shorter than the length of the girder body 31 and is not limited, but may be, for example, 2m. Sleeve 4 is positioned so that its longitudinal center is located at the adjacent ends of the two girder bodies 31a and 31b and is fixed to the girder bodies 31a and 31b with screws. As shown in Figure 2, sleeve 4 has an upper surface portion 41, a lower surface portion 42, a pair of side portions 43, a sleeve hollow portion 40, and a carbon fiber reinforced resin member 5. The sleeve hollow portion 40 is the space inside sleeve 4 and extends from one end to the other in the longitudinal direction.

[0015] As shown in Figure 2, the upper surface portion 41 is a flat surface that extends to the upper surface of the aluminum profile when installed inside the girder body 31. The upper surface portion 41 has a recessed surface 41a and an end surface 41b. The end surface 41b is located on both ends in the width direction in a cross-sectional view of the sleeve 4 and is a surface that extends from the ends in the width direction toward the center. The recessed surface 41a is recessed compared to the end surface 41b so that it is located slightly toward the hollow portion 40 of the sleeve. The recessed height of the recessed surface 41a is about 2 to 3 mm.

[0016] As shown in Figure 2, the lower surface 42 has a shape symmetrical to the upper surface 41 and includes a recessed plane 42a and an end plane 42b. The end plane 42b is located on both ends in the width direction in a cross-sectional view of the sleeve 4 and is a plane that extends from the ends in the width direction toward the center. The recessed plane 42a is recessed compared to the end plane 42b so that it is located slightly toward the hollow portion 40 of the sleeve. The recessed height of the recessed plane 42a is about 2 to 3 mm.

[0017] The pair of side surfaces 43 are flat surfaces that extend vertically in a state of being arranged within the digit main body 31 so as to connect the boundary between the end surface plane 41b and the concave surface plane 41a on the upper surface portion 41 and the boundary between the end surface plane 42b and the concave surface plane 42a on the lower surface portion 42.

[0018] The carbon fiber reinforced resin member 5 is a member formed by making a carbon fiber reinforced resin (Carbon Fiber Reinforced Plastics) in which carbon fibers are mixed with a resin material into a sheet shape. The carbon fiber reinforced resin member 5 is adhesively bonded and arranged to the concave surface plane 41a of the upper surface portion 41 and the concave surface plane 42a of the lower surface portion 42 with an adhesive 51. By adhering the carbon fiber reinforced resin member 5 to the sleeve 4, the rigidity of the sleeve 4 is improved. The surface of the carbon fiber reinforced resin member 5 is located at approximately the same height as the end surface planes 41b and 42b of the sleeve 4. The dimensions of the carbon fiber reinforced resin member 5 are smaller than those of the upper surface portion 41 or the lower surface portion 42 of the sleeve 4.

[0019] The above-described sleeve 4 is arranged within the hollow portion 30 of the digit main body 31. At this time, a gap G of 2.0 mm or less is formed between the surface of the carbon fiber reinforced resin member 5 and the inner peripheral surfaces 311a and 312a of the digit upper surface portion 311 and the digit lower surface portion 312 of the digit main body 31.

[0020] Table 1 shows the test results verifying the presence or absence of electrolytic corrosion when an alumite film and a boehmite film are formed on the inner peripheral surface of an aluminum plate and when they are not formed.

[0021]

Table 1

[0022] As Examples 1 to 3 and Comparative Examples 1 and 2, extruded profiles of 6063 aluminum alloy were used as test specimens. The dimensions of the test specimens were 100 mm in the longitudinal direction, 30 mm in the short transverse direction, and 2 mm in thickness. Also, a carbon fiber reinforced resin plate, which is a pultruded molded product of epoxy resin TRW40-50L manufactured by Mitsubishi Chemical Corporation, was fixed with a clearance of 2.0 mm from the test specimens. The dimensions of the carbon fiber reinforced resin plate were 100 mm in the longitudinal direction, 30 mm in the short transverse direction, and 2 mm in thickness.

[0023] As Examples 1 and 2, a boehmite film was formed on the test specimens. The test specimens were immersed in warm water at 80 degrees with an aluminum plate. In Example 1, the immersion was carried out for 5 minutes, and in Example 2, the immersion treatment was carried out for 10 minutes.

[0024] As Example 3, an alodine film was formed on the test specimens. The test specimens were subjected to an etching treatment for 5 minutes with a 50-degree aqueous sodium hydroxide solution to remove the natural oxide film formed on the surface of the test specimens. Then, the test specimens were immersed in a 15% sulfuric acid aqueous solution and an anodic oxidation treatment was carried out at a current density of 100 A / m 2 for 5 minutes.

[0025] In Comparative Example 1, before conducting the test, the test specimens were subjected to an etching treatment for 5 minutes with a 5% aqueous sodium hydroxide solution at 50 degrees to remove the natural oxide film formed on the surface of the test specimens.

[0026] In Comparative Example 2, after extruding the aluminum plates of the test specimens, the natural oxide film formed on the formed test specimens was left as it was.

[0027] <Measurement of corrosion current> Corrosion current was measured by passing an electric current through Examples 1-3 and Comparative Examples 1 and 2 obtained as described above. The test specimens were covered with vinyl tape with holes of 19 mm in diameter, and the test area was set by positioning the holes in the vinyl tape on the inner circumferential surface facing the carbon fiber reinforced resin side. The measurement was performed by stirring a 2.5% NaCl aqueous solution at 25 degrees Celsius with a stirrer at 250 rpm to equalize the temperature. The test specimens and carbon fiber reinforced resin plates were short-circuited via a non-resistivity ammeter HM-103A manufactured by Hokuto Denko Co., Ltd., and the measurement was performed. The obtained current densities are shown in Table 1.

[0028] <Salt spray test> The test specimens and carbon fiber reinforced resin plates were subjected to a 4800-hour neutral salt spray test as specified in JIS Z2371. This allowed the test solution to enter between the test specimen and the carbon fiber reinforced resin plate, causing them to make electrical contact through the test solution. After salt spraying, the treated test specimens from each of Examples 1 to Comparative Example 2 were visually evaluated by comparing their appearance: one specimen placed individually without being adjacent to the carbon fiber reinforced resin plate, and another specimen formed by integrating the treated specimens from Examples 1 to Comparative Example 2 with the carbon fiber reinforced resin plate with a 2.0 mm clearance. In Examples 1 to Comparative Example 2, if the corrosion state was similar to that of the individual test specimens, it was marked with ○. If the corrosion was accelerated compared to the individual test specimens placed without being adjacent to the carbon fiber reinforced resin plate, it was marked with ×.

[0029] <Rating> In Examples 1 and 2, the aluminum plates with a boehmite coating exhibited a low corrosion current density. The appearance of Examples 1 and 2 after salt spraying was similar to that of individual test specimens placed separately from the carbon fiber reinforced resin plate. Furthermore, in Example 2, which involved a longer immersion time in hot water, a thicker boehmite coating was obtained, and the thicker coating in Example 2 resulted in a lower corrosion current density.

[0030] In Example 3, the aluminum plate with the anodized coating had a lower corrosion current density than in Examples 1 and 2. The appearance of Example 3 after salt spraying was similar to that of a single test specimen placed separately from a carbon fiber reinforced resin plate. The resulting coating was thinner than that of Examples 1 and 2.

[0031] In Comparative Examples 1 and 2, the corrosion current density was high, indicating that current flowed easily. After salt spraying, the appearance of Comparative Examples 1 and 2 showed accelerated corrosion compared to the test samples placed separately from the carbon fiber reinforced resin plate.

[0032] It was found that by forming an anodized or boehmite coating on the surface of the aluminum plate facing the carbon fiber reinforced resin plate, corrosion of the aluminum plate can be suppressed even when the aluminum plate is placed adjacent to the carbon fiber reinforced resin plate.

[0033] This embodiment provides the following advantages. The aluminum profile connecting structure 1 comprises a pair of aluminum profiles, each having a hollow section 30 and connected by butt joints, a sleeve 4 provided at the connecting section 32 of the pair of girder bodies 31 and inserted into the hollow section 30, and a carbon fiber reinforced resin member 5 positioned on the surface of the sleeve 4. An anodized coating 33 or boehmite coating 34 is provided on the inner circumferential surfaces of the pair of girder bodies 31 at the connecting section 32. This reinforces the aluminum sleeve 4 with the carbon fiber reinforced resin member 5, while preventing rainwater or the like from coming into contact with the inner circumferential surface of the hollow section 30 of the girder body 31 facing the carbon fiber reinforced resin member 5, causing electric current to flow and corrosion. Therefore, electrolytic corrosion can be easily prevented without providing other materials such as glass fiber reinforced resin.

[0034] According to this embodiment, a gap of 2.0 mm or less is formed between the carbon fiber reinforced resin member 5 and the inner circumferential surfaces 311a and 312a. Even though a gap of 2.0 mm or less G is formed between the carbon fiber reinforced resin member 5 and the inner circumferential surfaces 311a and 312a, electrolytic corrosion of the girder body 31 is prevented because an anodized coating 33 or a boehmite coating is provided on the inner circumferential surfaces 311a and 312a.

[0035] This disclosure is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of this disclosure are included. The dimensions and other specifications described above are for illustrative purposes only and can be changed as appropriate. [Explanation of symbols]

[0036] 1 Aluminum profile connecting structure, 4 Sleeve, 5 Carbon fiber reinforced resin member, 30 Hollow section, 31 Beam body (aluminum profile), 32 Connecting section, 33 Anodized coating, 34 Boehmite coating, 311a, 312a Inner circumferential surface

Claims

1. A pair of aluminum profiles having a hollow section and being butted together and connected, A sleeve is provided at the connecting portion of the pair of aluminum profiles and inserted into the hollow portion, The sleeve comprises a carbon fiber reinforced resin member disposed on the surface of the sleeve, An aluminum profile connecting structure wherein the inner circumferential surfaces of the pair of aluminum profiles in the connecting portion are provided with an anodized coating or a boehmite coating.

2. The aluminum profile connecting structure according to claim 1, wherein a gap of 2.0 mm or less is formed between the carbon fiber reinforced resin member and the inner circumferential surface.

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