Hollow structure

Abstract

To provide a technique for realizing a hollow structure as a lightweight hollow frame with fewer manufacturing processes.SOLUTION: A hollow structure 1 has: a hollow structure body 1a; and a connecting part 1b integrally provided at least at one end of the hollow structure body 1a and connected to another member. The connecting part 1b has: a connecting part body 1c integrally provided to make the hollow structure continuous with the hollow structure body 1a; and a fastening part 3 provided to close an opening at an end of the hollow structure and fastened to the other member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hollow structure.

Background Art

[0002] In the fields of office furniture, stationery, building materials, and industrial equipment, products using a hollow frame made of a hollow structure as a constituent member are known. As the hollow structure, generally, a molded product of a metal material such as an iron-based material has been used. On the other hand, for the purpose of speeding up the operation and downsizing of a hollow structure such as a hollow frame, weight reduction is achieved by using a molded product of a resin material. Further, as the usage area expands, at the same time, strengthening of the bonding strength with other structures is also attempted.

[0003] For example, Patent Document 1 discloses a technique for weight reduction using a link structure made of a fiber-reinforced plastic.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the joint structure of the fiber-reinforced plastic link structure as described in Patent Document 1 is a composite in which the fiber-reinforced plastic and the metal mounting seat are joined by an adhesive such as a urethane-based adhesive or an epoxy-based adhesive, or a joining method using a combination of the adhesive and mechanical fastening. Therefore, the manufacturing process is complicated, and a technique capable of manufacturing a hollow structure with a small number of manufacturing steps has been demanded.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for realizing a hollow structure as a hollow frame excellent in lightness with a small number of manufacturing steps.

Means for Solving the Problems

[0007] According to the present invention, there are provided a hollow structure body, a connecting portion integrally provided at at least one end of the hollow structure body and connected to another member, and the connecting portion includes a connecting portion main body integrally provided so as to continue the hollow structure of the hollow structure body, a fastening portion provided so as to close an opening at an end of the hollow structure and fastened to another member, and a hollow structure body is provided.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a technique for realizing a hollow structure as a hollow frame excellent in lightness with a small number of manufacturing steps.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by common reference numerals, and the description thereof will be omitted as appropriate. Also, the figures are schematic and do not match the actual dimensional ratios. The symbol "~" between the numbers in the text represents "from above to below" unless otherwise specified.

[0011] <Outline of the hollow structure 1> FIG. 1 is a perspective view schematically showing an example of the structure of the hollow structure 1. The hollow structure 1 (also referred to as a "hollow molded part" or a "hollow frame") includes a hollow structure body 1a and a connecting portion 1b provided at at least one end of the hollow structure body 1a. The hollow structure body 1a and the connecting portion 1b are formed of a thermoplastic resin or a light metal alloy (including light metals). That is, the hollow structure body 1a and the connecting portion 1b are integrally formed (in a seamless state). The shape of the hollow structure body 1a is, for example, pipe-shaped. The connecting portion 1b may be provided at one end of the hollow structure body 1a, or may be provided at both ends as shown in the figure.

[0012] When the hollow structure body 1a and the connecting portion 1b are made of a thermoplastic resin, the hollow structure body 1a and the connecting portion 1b can be formed, for example, by an injection molding method. When the hollow structure body 1a and the connecting portion 1b are made of a light metal alloy, the hollow structure body 1a and the connecting portion 1b can be formed by a die-casting method.

[0013] Since the hollow structure 1 is composed of a lightweight thermoplastic resin or a light metal alloy for the hollow structure body 1a and the connecting portion 1b, it is excellent in light weight. Furthermore, in the hollow structure 1, the hollow structure body 1a and the connecting portion 1b are integrally formed seamlessly. In other words, the hollow structure 1 having the hollow structure body 1a and the connecting portions 1b at both ends thereof can be manufactured in fewer manufacturing steps, more specifically, in a single molding process. Also, compared with conventional hollow molded parts using adhesives or the like, the risk of breakage between the hollow structure body 1a and the connecting portion 1b can be reduced. From the above, according to the present embodiment, it is possible to provide the hollow structure 1 in which the risk of breakage between the hollow structure body 1a and the connecting portion 1b is reduced and which is excellent in lightness.

[0014] <hollow structure body 1a> The shape of the hollow structure body 1a is not particularly limited as long as it can form a hollow frame structure. For example, the axis is straight, and the cross-sectional shape of the hollow structure body 1a in the short direction may be the same or different. For example, it may be any of circular, elliptical, oval, semi-circular, or rectangular. The size of the cross-section of the hollow structure body 1a may be the same or different at any point in the longitudinal direction of the hollow structure body 1a. When different, it is preferably the smallest at the midpoint in the longitudinal direction of the hollow structure body 1a and the largest at both ends of the hollow structure body 1a. In other words, it is preferable that the cross-sectional shape of the hollow structure body 1a in the short direction is the largest at both ends of the hollow structure body 1a. By adopting such a shape, the appearance becomes a smart structure and can contribute to the weight reduction of the entire hollow structure 1. In the present embodiment, "the size of the cross-section at point A is larger than the size of the cross-section at point B" is defined as that when viewed directly along the axis from the longitudinal direction, the cross-section forming frame at point B is completely within the cross-section forming frame at point A, and it should be noted that it is not simply determined by comparing the cross-sectional areas of point A and point B. From the viewpoints of the mechanical strength, ease of manufacturing, and resistance to stress applied in the short direction of the hollow structure 1, the cross-sectional shape of the hollow structure body 1a is preferably circular, oval, or rectangular. FIGS. 1 to 5 illustrate a hollow molded part in which the cross-section of the hollow structure body 1a is rectangular.

[0015] <connecting portion 1b> The connecting part 1b has a connecting part main body 1c integrally provided so as to continue the hollow structure body main body 1a and the hollow structure, and a fastening part 3 provided so as to close the opening at the end of the hollow structure and fastened to other members. The fastening part 3 has a substantially annular shape. The connecting part main body 1c extends cylindrically from the substantially annular outer contour of the fastening part 3 and is continuously connected to the hollow structure body main body 1a on the cylindrical side surface. In the present embodiment, the outer diameter of the fastening part 3 is narrower than the width in the short side direction of the hollow structure body main body 1a, but it may be the same.

[0016] In addition, when the hollow structure body 1 rotates around the connecting part 1b (more specifically, the fastening part 3), a fastening part 3 having a rotation center axis 3b is formed in the connecting part 1b. When the fastening parts 3 for connection are at both ends of the hollow structure body main body 1a, it is more preferable from the manufacturing viewpoint that the two rotation center axes 3b are parallel to each other with respect to the axis.

[0017] <Fastening part 3> The shape of the fastening part 3 is a disk shape, and more specifically, it is an annular shape provided with an opening for passing cables such as power lines and signal lines inside the hollow structure body 1. It is preferable that a plurality of screw holes 3a (through holes) for fixing other structures (mounted members) are formed in the fastening part 3. The number of the screw holes 3a is not particularly limited, but is usually 5 to 20, preferably 8 to 15. In addition, it is preferable that the plurality of screw holes 3a are provided at predetermined intervals in the circumferential direction of the disk-shaped fastening part 3. In this case, it is preferable that the plurality of screw holes 3a are provided at equal intervals.

[0018] A metal plate may be bonded to the bottom surface (outer surface) of the fastening portion 3 as needed. By arranging the metal plate, it can function as a seating surface for the mounting screw, and thus it may be possible to prevent the mounting screw from loosening. Examples of the metal plate include aluminum alloy, titanium alloy, copper alloy, magnesium alloy, stainless steel, etc. As a method of bonding the metal plate to the bottom surface of the fastening portion 3, for example, a method of insert molding a thermoplastic resin into the metal plate during the molding of the hollow structure 1 is preferably adopted. When the material of the hollow structure 1 is a thermoplastic resin as described later, by surface-treating the metal plate, a fine concavo-convex structure is formed on the surface of the metal plate, and the thermoplastic resin is preferably injection-molded onto the metal plate so that the surface on which the fine concavo-convex structure is formed becomes the bonding surface side.

[0019] The fastening portion 3 is provided inside the connecting portion 1b. That is, it does not protrude outward from the connecting portion main body 1c in a flange shape. With this configuration, when the hollow structure 1 is attached to another structure, the fastening portion 3 is not visible from the outside, that is, the screw hole 3a and the screw used for fastening can be hidden. This can improve the design property of the hollow structure 1. Also, it is possible to eliminate catching or the like due to the shape of the screw hole 3a or the screw used for fastening, and it is possible to avoid the trouble of preparing a cover or the like to cover them.

[0020] <Opening 2> FIG. 2 is a perspective view schematically showing an example of the structure of the hollow structure 1, and is a view showing an example of the structure of a hollow molded part in which the opening 2 is fitted and closed with a cap 4. FIG. 4 is a perspective view showing a structure in which the cap 4 is fitted and closed to the cross-sectional structure of the hollow structure 1 shown in FIG. 3.

[0021] The connecting portion 1b has an opening 2 as an opening that communicates the inside and outside of the hollow structure 1. The opening 2 is used for performing various operations such as an operation of fixing a cable assembly along the fastening portion 3 and an operation of passing a male screw through a screw hole provided in the fastening portion 3 and fastening and fixing it with a female screw.

[0022] The size of the opening 2 is not particularly limited, but preferably, when the hollow structure 1 is viewed from the longitudinal direction (for example, in the S direction in FIG. 1), the area (A1) within the frame line X1 formed by the innermost contour of the hollow structure main body 1a is usually 50 to 100 area %, preferably 60 to 95 area %, more preferably 65 to 90 area % of the area (A0) within the frame line X2 formed by the opening 2 (see FIG. 5). In FIG. 5, the A1 / A0 value is about 73 area %.

[0023] By setting the opening shape to a size that satisfies such requirements, the efficiency of various operations performed through the opening 2 can be improved, and the hollow structure 1 can be efficiently removed from the mold when molded, for example, by injection molding.

[0024] When no operation is being performed, the opening 2 may be fitted and closed, for example, by a detachable cap 4 in order to prevent the entry of foreign matter such as dust, prevent water ingress when exposed to water, and prevent accidents such as an operator's clothing being caught. The fitting and closing method is not particularly limited, and any detachable fitting method that allows for easy locking and unlocking can be used without limitation. For example, a screw mechanical fastening method or a snap fit, which is a fastening method that does not use screws, is also preferably used. A snap fit is formed with a claw portion on one member constituting the product, and a fixing portion, that is, a claw locking portion, into which this claw portion fits, is provided at a corresponding position on the other member, which is the mating member. By combining and fixing the claw portion and the claw locking portion of each member, a structure such as a housing composed of a plurality of members is assembled into one. A snap fit has the advantage of facilitating the work when assembling the structure without drilling holes in the members.

[0025] <Material of the hollow structure 1> The hollow structure main body 1a and the connecting portion 1b constituting the hollow structure 1 are each composed of at least one material selected from a thermoplastic resin and a light metal alloy, and a thermoplastic resin is preferable from the viewpoint of further improving the light weight of the hollow structure 1. One of the key points of this embodiment is that the hollow structure 1 is formed seamlessly. The hollow structure 1 is formed, for example, by die-casting of a light metal alloy or injection molding of a thermoplastic resin. Among these molding methods, the injection molding method using a thermoplastic resin is preferable from the viewpoint of improving the lightweight property of the entire hollow structure 1.

[0026] As the aluminum alloy of the light metal alloy, from the viewpoint of passing through a narrow gate with high fluidity, for example, ADC1, ADC3, ADC5, ADC6, ADC10, ADC10Z, ADC12, ADC12Z, etc., which are aluminum alloys for die-casting, can be mentioned. As the magnesium alloy, AZ91, AM60, etc. can be mentioned. When the hollow structure 1 is made of a light metal alloy, the hollow structure 1 can be manufactured under known conditions using a known die-casting machine including, for example, a mold with a cavity formed therein, an injection sleeve formed in a substantially cylindrical shape so as to have an internal space and communicating with the cavity at one end side thereof, and a plunger tip movably disposed within the injection sleeve.

[0027] On the other hand, as the injection molding method, a known method can be used without limitation. That is, when the hollow structure 1 is made of a thermoplastic resin, the hollow structure 1 is manufactured, for example, by attaching the metal plate as necessary to a cavity formed between a movable mold and a fixed mold, then injecting and filling a molten thermoplastic resin or a thermoplastic resin composition, and then opening the mold and removing slides and inserts used as necessary.

[0028] When the hollow structure 1 is formed by the injection molding method, the raw material component of the thermoplastic resin is a thermoplastic resin composition containing a thermoplastic resin as a resin component and further containing additives as necessary. As the thermoplastic resin, one or more thermoplastic resins selected from polyolefin resins, polyester resins, polyamide resins, polyacetal resins, polycarbonate resins, fluorine resins, polyarylene ether resins, polyarylene sulfide resins, ABS resins, and polyamide-containing alloys are preferably used because they can improve the mechanical strength of the hollow structure 1. Among these, polyamide resins and polyester resins are more preferred, and polyamide resins are particularly preferred. As the polyamide-containing alloy, an alloy of a polyamide resin and a polyarylene ether resin can be cited as a preferred example.

[0029] Specific examples of polyamide resins include aliphatic polyamides such as nylon 6, nylon 66, nylon 11, and nylon 12, semi-aromatic polyamide resins such as polyhexamethylene terephthalamide and polyhexamethylene isophthalamide, and polyamide resins obtained from metaxylylenediamine. Among these polyamide resins, a polyamide resin obtained from metaxylylenediamine and adipic acid is particularly preferred. Such a polyamide resin is called nylon MXD6 and is commercially available, for example, under the trade name of Reny TM from Mitsubishi Engineering Plastics Corporation.

[0030] The thermoplastic resin composition may contain, for example, one or more additives selected from the group consisting of inorganic fillers, flame retardants, flame retardant aids, heat stabilizers, antioxidants, pigments, weathering agents, plasticizers, dispersants, lubricants, mold release agents, antistatic agents, impact resistance improvers, and colorants.

[0031] Examples of the inorganic filler include fibrous fillers (such as glass fibers and carbon fibers), powdery and granular fillers (such as kaolin and talc), and plate-like fillers (such as mica). Among these fillers, fibrous fillers, particularly glass fibers (such as chopped strands), are preferred in terms of having high strength and rigidity. These fillers can be used alone or in combination of two or more.

[0032] These fillers may be used in combination with a converging agent or a surface treatment agent. Examples of such a converging agent or surface treatment agent include functional compounds. Examples of the above functional compounds include epoxy compounds, silane compounds, titanate compounds, and the like. The amount of the inorganic filler is, for example, 0 to 60% by weight, preferably 5 to 60% by weight in the thermoplastic resin composition.

[0033] As the flame retardant, known halogen-based flame retardants such as brominated epoxy polymers and decabromodiphenyl ether, and phosphorus-based flame retardants can be used without limitation. However, when a polyamide-based resin is used as the base resin and a color tone other than black is required for the molded body, halogenated bisimide can be exemplified as a suitable flame retardant. When using a flame retardant, its content is, for example, 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass per 100 parts by mass of the thermoplastic resin composition.

[0034] In this embodiment, a general colorant can be blended into the resin. Examples of the black colorant (black pigment) used include carbon black, graphite, titanium black, black iron oxide, and the like. Among these, carbon black is particularly desirable in terms of dispersibility, color development, and cost. The black pigment can be used alone or in combination of two or more.

[0035] In addition, non-black colorants are those other than the above black pigments, and examples include inorganic pigments and organic pigments described later. These non-black colorants can be used alone or in combination of two or more. Examples of non-black pigments include white pigments (e.g., calcium carbonate, titanium oxide, zinc oxide, zinc sulfide, etc.), yellow pigments (e.g., cadmium yellow, lead yellow, titanium yellow, zinc chromate, loess, yellow iron oxide, etc.), red pigments (e.g., red mouth pigment, amber, red iron oxide, cadmium red, etc.), blue pigments (e.g., ultramarine blue, ultramarine, cobalt blue, etc.), green pigments (e.g., chrome green, etc.), and the like.

[0036] In addition, as the organic pigment, for example, azo-based, azomethine-based, methine-based, indanthrone-based, anthraquinone-based, pyranthrone-based, flavanthrone-based, benzenesulphone-based, phthalocyanine-based, quinophthalone-based, perylene-based, perinone-based, dioxazine-based, thioindigo-based, isoindolinone-based, isoindoline-based, pyrrolopyrrole-based, quinacridone-based, etc. can be mentioned.

[0037] The blending amount of the non-black colorant is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 18 parts by mass, and still more preferably 0.5 to 15 parts by mass per 100 parts by mass of the thermoplastic resin composition.

[0038] In addition to the above-mentioned inorganic filler, flame retardant, and colorant, the thermoplastic resin composition can be blended with other additives within a range that does not impair the effects of the present invention. Examples of various additives include heat stabilizers such as copper-based heat stabilizers and phosphorus-based heat stabilizers, antioxidants such as hindered phenol-based antioxidants, mold release agents, weather resistance improvers, nucleating agents, foaming agents, impact resistance improvers, lubricants, plasticizers, fluidity improvers, etc. When using other additives in combination, the blending amount is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass per 100 parts by mass of the resin composition.

[0039] <Material of Cap 4> As the material constituting Cap 4, for example, various materials such as resin, light metal alloy, and wood can be used. In the case of resin or light metal alloy materials, it may be composed of the same material as the hollow structure body main body 1a or a different material. When Cap 4 is made of resin, the thermoplastic resin or thermoplastic resin composition for manufacturing the hollow structure 1 can be used without limitation as the resin. That is, as the resin constituting Cap 4, polyamide-based resins and polyester-based resins are more preferable, and polyamide-based resins are particularly preferable. Cap 4 can be molded using known molding methods such as injection molding, extrusion molding, vacuum molding, blow molding, pressure air molding, compression molding, etc. From the viewpoint of productivity, it is preferable to use injection molding and extrusion molding for molding.

[0040] The embodiments of the present invention have been described above with reference to the drawings. These are examples of the present invention, and various configurations other than the above can also be adopted.

[0041] The features of this embodiment are summarized as follows. [1] The hollow structure 1 has a hollow structure main body 1a, a connecting portion 1b provided integrally at at least one end of the hollow structure main body 1a and connected to other members, and the connecting portion 1b has a connecting portion main body 1c provided integrally so as to continue the hollow structure with the hollow structure main body 1a, a fastening portion 3 provided so as to close the opening at the end of the hollow structure and fastened to other members. [2] The fastening portion 3 has a substantially annular shape, and the connecting portion main body 1c extends from the outer contour of the substantially annular shape. [3] The connecting portion main body 1c has an opening 2. [4] It has a cap 4 (lid portion) removably fitted into the opening 2. [5] The fastening portion 3 has a plurality of screw holes 3a (through holes) provided at predetermined intervals in the circumferential direction for use in connecting to other members. [6] The shape of the cross section perpendicular to the extending direction of the hollow structure main body 1a is circular, elliptical, oval, semi-circular or rectangular. [7] The hollow structure main body 1a and the connecting portion 3 may be made of a thermoplastic resin. [8] The hollow structure main body 1a and the connecting portion 3 may be made of a light metal or a light metal alloy.

Explanation of Reference Numerals

[0042] 1 Hollow structure 1a Frame main body 1b Connecting portion 1c Connecting portion main body 2 Opening​ 3 Fastening part 3a Threaded hole 3b Rotation center axis 4 Cap X1 Frame line formed by the innermost contour of the hollow structure body X2 Frame line formed by the opening

Claims

Claim 1: A hollow structure body extending in the longitudinal direction, a connecting portion integrally provided at at least one end of the hollow structure body and connected to other members, and having, the connecting portion comprising: a connecting portion main body provided such that the hollow structure is continuous with the hollow structure body, and a fastening portion fastened to other members. The fastening portion has an annular shape with an opening at the center, a part of the outer contour of the annular shape extending from the outer contour of the connecting portion main body, the connecting portion main body having an opening, when viewed from the longitudinal direction of the hollow structure body, a first frame line formed by the innermost contour of the hollow structure body is located inside a second frame line formed by the opening, and the area of the region surrounded by the first frame line is 50 to 100 area% of the area of the region surrounded by the second frame line. A hollow structure. Claim 2: The hollow structure according to claim 1, further comprising a lid removably fitted into the opening. Claim 3: The fastening portion has a plurality of through holes provided at predetermined intervals in the circumferential direction and used for connection with other members. The hollow structure according to claim 1 or 2. Claim 4: The shape of a cross section perpendicular to the extending direction of the hollow structure body is circular, elliptical, oval, semi-circular or rectangular. The hollow structure according to any one of claims 1 to 3. Claim 5: The hollow structure body and the connecting portion are made of a thermoplastic resin. The hollow structure according to any one of claims 1 to 4. Claim 6: The hollow structure body and the connecting portion are made of a light metal or a light metal alloy. The hollow structure according to any one of claims 1 to 4. ​ ​ ​ ​ ​ ​

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