Hollow structure

Abstract

To provide a hollow structure capable of reducing braking risk of a connection part to a driving source such as a motor or to another structure, and excellent in lightness.SOLUTION: A hollow structure 1 has a hollow structure body 10, a joint part 50 provided on the hollow structure body 10, and having a center opening (joint opening), and recesses (a semi-cylindrical recess 21, a cylindrical recess 22) extending in an opening direction from the joint part 50 so as to enclose cylindrically open holes 56, 57, when the hollow structure body 10 exists in the opening direction of open holes 55, 56, 57, in the joining open holes 55, 56, 57 of the joint part 50.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In the fields of office furniture, stationery, and industrial equipment, products using a hollow frame made of a hollow structure as a constituent member are known. Generally, a molded product of a metal material such as an iron-based material has been used as the hollow structure. On the other hand, for the purpose of speeding up the operation and miniaturizing a hollow structure such as a hollow frame, weight reduction is achieved by using a molded product of a resin material.

[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] The fiber-reinforced plastic link structure as described in Patent Document 1 is a composite in which a fiber-reinforced plastic and a 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 above adhesive and mechanical fastening. Therefore, the manufacturing process is complicated. In addition, there is a concern that the joint portion between the fiber-reinforced plastic and the metal mounting seat may be broken when transmitting torque from a drive source (for example, a drive motor).

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a hollow structure having excellent light weight and reducing the risk of breakage at a connection portion with a drive source such as a motor or another structure.

Means for Solving the Problem

[0007] According to the present invention, [1] a hollow structure body, a joint portion provided on the hollow structure body and having a central opening, and in a through hole for fastening provided in the joint portion, when the hollow structure body exists in the opening direction of the through hole, a hollow structure is provided which has a recess extending in the opening direction from the joint portion so as to surround the through hole in a cylindrical shape. [2] The hollow structure body extends integrally with the joint portion and has a connecting portion that changes the extending direction from the opening direction of the central opening to a direction different from the opening direction, and an extending portion extending in the extending direction different from the opening direction, and at the boundary between the connecting portion and the extending portion, the hollow structure according to [1] above is provided, in which the joint portion and the connecting portion are integrally formed. [3] The hollow structure body is narrower than the outer diameter of the joint portion, and the hollow structure according to [1] or [2] above is provided. [4] The hollow structure body has a region that gradually widens from the joint portion, and the hollow structure according to any one of [1] to [3] above is provided. [5] The hollow structure body has a region that gradually narrows from the joint portion, and the hollow structure according to any one of [1] to [4] above is provided. [6] A collar is provided in the through hole of the joint portion, and the hollow structure according to any one of [1] to [5] above is provided. [7] A reinforcing member is provided on the joint surface of the joint portion, and the hollow structure according to any one of [1] to [6] above is provided. [8] The hollow structure body and the joint portion are injection molded bodies made of a resin composition, and the hollow structure according to any one of [1] to [7] above is provided. [9] The hollow structure body and the joint portion are cast products of a metal material, and the hollow structure according to any one of [1] to [7] above is provided.

Advantages of the Invention

[0008] According to the present invention, it is possible to reduce the risk of destruction of the connection portion with a drive source such as a motor or other structures, and to provide a hollow structure excellent in light weight.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes 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 drawings are schematic views and do not match the actual dimensional ratios.

[0011] FIG. 1 is a perspective view schematically showing an example of the structure of the hollow structure 1 according to the present embodiment. FIG. 2 is a plan view of the hollow structure 1. FIG. 3 is a front view of the hollow structure 1. FIG. 4 is a side view of the hollow structure 1. FIG. 5 is a view corresponding to the arrow A1 in FIG. 2. FIG. 6 is a cross-sectional view taken along the line A2 - A2 in FIG. 2. FIG. 7 is a cross-sectional view taken along the line A3 - A3 in FIG. 3.

[0012] <Outline of the hollow structure 1> The hollow structure 1 includes a hollow structure main body 10 and a joint portion 50 provided at at least one end of the hollow structure main body 10. The hollow structure 1 is used for products in the office furniture field, stationary field, and industrial equipment field. The hollow structure 1 is an injection molded body made of a resin composition or a casting of a metal material, in which the hollow structure main body 10 and the joint portion 50 are integrally provided. In the present embodiment, as shown in FIGS. 2 and 3, the joint portion 50 is provided at the left end of the hollow structure main body 10.

[0013] <Hollow structure main body 10> The hollow structure main body 10 has an extension portion 11 and a connection portion 20 provided at one end of the extension portion 11. The connection portion 20 changes the direction of the extension direction of the extension portion 11 and is connected to the joint portion 50. The extension portion 11 and the connection portion 20 are formed substantially seamlessly (that is, without a seam).

[0014] <Extension portion 11> The extension portion 11 is a hollow body (hollow frame) that extends linearly in a cylindrical shape with the same diameter for a predetermined length. The wall thickness of the extension portion 11 is determined by the required mechanical strength and the material used (such as a resin composition or an aluminum alloy).

[0015] Further, the shape of the extending portion 11 is not particularly limited as long as it can form a hollow frame. The extending direction (i.e., the axis) may be straight or curved. Also, the cross-sectional shape in the width direction (the direction perpendicular to the extending direction) of the extending portion 11 may be the same throughout the entire region in the extending direction or may be different. For example, it may be any of circular, elliptical, oval, semi-circular, or rectangular shapes. Also, the extending portion 11 is not limited to a configuration in which the outer diameter extends with the same diameter size, and may have a region that gradually widens or a region that gradually narrows. That is, the size of the above cross-sectional shape may change. In addition, from the viewpoints of the mechanical strength of the hollow structure 1, ease of manufacturing, and resistance to stress applied in the short-side direction, a circular, elliptical, or rectangular cross-sectional shape of the extending portion 11 is preferably used.

[0016] <Connection portion 20> The connection portion 20 has a substantially cylindrical shape and has a function of changing the extending direction in a predetermined direction. In this embodiment, the opening direction of the joint opening 53 of the joint portion 50 is changed by 90 degrees. For example, referring to FIG. 3, the opening of the joint opening 53 is upward, but the connection portion 20 converts the direction of the extending portion 11, that is, the extending direction, to the horizontal direction (right direction in FIG. 3). Note that the conversion direction (angle) is not intended to be limited to 90 degrees (i.e., horizontal). For example, in FIG. 3, an angle that becomes obliquely upward (e.g., 45 degrees) or a conversion may be made so as to rotate 180 degrees and become downward. When assuming injection molding of a resin composition or molding by casting an aluminum alloy or the like, considering the mold release, the conversion angle is preferably within 90 degrees. Note that the shape of the connection portion 20 can also be various shapes similar to the extending portion 11. However, from the viewpoints of mechanical strength (particularly suppression of stress concentration) and ease of manufacturing, it is preferably a shape that is substantially continuously the same as the shape of the extending portion 11.

[0017] <Joint portion 50> As shown in the plan view of Fig. 2, the joint portion 50 is annularly provided so as to project outward by a predetermined width outside the connection portion 20 in a top view. That is, it can be said that the outer diameter of the hollow structure body 10 is narrower than that of the joint portion 50. Note that a part of the joint portion 50 (the right part in Fig. 2) is covered by the connection portion 20 and the extension portion 11.

[0018] A plurality of through holes 55, 56, 57 penetrating the joint surface 51 and the joint back surface 52 are provided in the joint portion 50. Here, the through holes 55, 56, 57 are provided at a total of 12 positions equally spaced in the circumferential direction. The through holes 55, 56, 57 are used for connection with a drive source such as a motor and other structures (hereinafter referred to as "other structures"). Note that, for example, a metal collar may be provided in the through holes 55, 56, 57.

[0019] In the through holes 55, 56, 57 of the joint portion 50, when the hollow structure body 10 of the connection portion 20 or the extension portion 11 exists in the opening direction (here, the upward direction) of the through holes 55, 56, 57, recesses (semicylindrical recess 21 and cylindrical recess 22) extending in the opening direction (here, the upward direction) from the joint surface 51 of the joint portion 50 are provided so as to surround the through holes 56, 57 in a cylindrical shape.

[0020] Regarding the two through holes 56 provided near the outer shape boundary of the connection portion 20, the semi-cylindrical recess 21 is provided in a concave shape toward the opening direction of the through holes 56 so as to cover the periphery thereof in a semi-cylindrical shape. That is, the semi-cylindrical recess 21 is provided so as to open a part of the connection portion 20 in the opening direction of the through holes 56.

[0021] With such a configuration, even when the through hole 56 provided in the joint portion 50 is in a position hidden by the connection portion 20, it can be surely used, and fastening with other structures in the joint portion 50 can be surely performed.

[0022] Regarding the two through holes 57 provided in a region that completely overlaps with the connection part 20, a cylindrical recess 22 is provided in a concave shape toward the opening direction of the through holes 57 so as to cover the periphery thereof in a cylindrical shape. That is, the cylindrical recess 22 is provided so as to open a part of the connection part 20 in the opening direction of the through holes 57.

[0023] With such a configuration, even when the through holes 57 provided in the joint part 50 are in a position hidden by the connection part 20, they can be surely used, and fastening with other structures in the joint part 50 can be surely performed. Further, as shown in FIGS. 5 and 7, the two cylindrical recesses 22 are separated from each other, and since the inside of the connection part 20 and the inside of the extension part 11 are communicated between them, sufficient space can be secured even when wiring electric wires or the like inside.

[0024] The joint opening 53 of the joint part 50 is continuous with the hollow structures of the connection part 20 and the extension part 11, and cables such as power lines and signal lines can be passed through the inside of the hollow structure 1. Note that a reinforcing member such as a metal plate may be bonded to the joint back surface 52 (or the joint front surface 51) of the joint part 50 as necessary. By arranging the reinforcing member, it is possible to prevent the resin member from being broken by the tightening torque acting when fastening the hollow structure 1 to other structures or loosening due to creep. 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 joint back surface 52 or the like, for example, a method of insert molding a thermoplastic resin into the metal plate during the molding of the hollow structure 1 can be used.

[0025] <Material of the hollow structure 1> The hollow structure 1 is, for example, an injection molded body of a resin composition or a casting of a metal material.

[0026] When the resin composition is a thermoplastic resin, the hollow structure 1 can be formed, for example, by an injection molding method. When the metal material is an aluminum alloy, it can be formed, for example, by an aluminum die-casting method. With such a configuration, a hollow structure 1 excellent in lightness and having a desired strength can be realized. Further, since the hollow structure 1 is integrally formed, the risk of breakage can be suppressed as compared with hollow structures of other configurations using an adhesive or the like.

[0027] Examples of the aluminum alloy include ADC1, ADC3, ADC5, ADC6, ADC10, ADC10Z, ADC12, ADC12Z, etc., which are aluminum alloys for die-casting, from the viewpoint of passing through a narrow gate with high fluidity. When the configuration uses an aluminum alloy, the hollow structure 1 can be manufactured under known conditions using a known die-casting machine including, for example, a mold in which a cavity is formed, 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 in the injection sleeve.

[0028] When the resin composition (thermoplastic resin) is used, as the injection molding method, a known method can be used without limitation. That is, the hollow structure 1 is manufactured by, for example, attaching the metal plate to a cavity formed between a movable mold and a fixed mold as needed, then injecting and filling a molten thermoplastic resin or a thermoplastic resin composition, then opening the mold, and removing slides and inserts used as needed.

[0029] When the hollow structure 1 is formed by an injection molding method, the thermoplastic resin as a raw material component is a thermoplastic resin composition containing a thermoplastic resin as a resin component and further containing additives as needed. 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 preferable, and polyamide resins are particularly preferable. As the polyamide-containing alloy, an alloy of a polyamide resin and a polyarylene ether resin can be cited as a preferred example.

[0030] 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 preferable. 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.

[0031] The thermoplastic resin composition according to this embodiment 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.

[0032] 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 preferable in terms of having high strength and rigidity. These fillers can be used alone or in combination of two or more.

[0033] 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 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.

[0034] 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 resin is used as the base resin and a color tone other than black is required for the molded article, halogenated bisimide can be exemplified as a suitable flame retardant. When a flame retardant is used, 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.

[0035] In this embodiment, a general colorant can be blended with the resin. Examples of the black colorant (black pigment) used in this embodiment 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.

[0036] In addition, the non-black colorant is other than the above black pigment, 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 the non-black pigment 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.

[0037] Also, examples of the organic pigment include azo-based, azomethine-based, methine-based, indanthrone-based, anthraquinone-based, pyranthrone-based, flavanthrone-based, benzeneslone-based, phthalocyanine-based, quinophthalone-based, perylene-based, perinone-based, dioxazine-based, thioindigo-based, isoindolinone-based, isoindoline-based, pyrrolopyrrole-based, quinacridone-based, etc.

[0038] 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.

[0039] In addition to the above inorganic filler, flame retardant and colorant, the thermoplastic resin composition according to this embodiment can be blended with other additives as long as the effects of the present invention are not impaired. 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 other additives are used 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.

[0040] As described above, the embodiments of the present invention have been described with reference to the drawings, but 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 of this embodiment is a hollow structure main body 10, a joint portion 50 provided on the hollow structure main body 10 and having a central opening (joint opening 53), In the through holes 55, 56, 57 for fastening the joint portion 50, when the hollow structure body main body 10 exists in the opening direction of the through holes 55, 56, 57 (here, the through holes 56, 57), recesses (semicylindrical recess 21, cylindrical recess 22) extending in the opening direction (upward direction in the drawing) from the joint portion 50 are provided so as to surround the through holes 56, 57 in a cylindrical shape. That is, as shown in FIG. 2, when the through holes 56, 57 overlap the hollow structure body main body 10 when viewed from above, cylindrical frames (here, the semicylindrical recess 21, cylindrical recess 22) are provided from above to the joint portion 50. Even when the through holes 56, 57 provided in the joint portion 50 are in positions hidden by the hollow structure body main body 10 (here, the connection portion 20), they can be surely used, and fastening between the joint portion 50 and other structures can be surely performed. (2) The hollow structure body main body 10 extends integrally with the joint portion 50, and has a connection portion 20 that extends from the opening direction (here, the upward direction) of the central opening (joint opening 53) to a direction different from the opening direction (here, the horizontal direction), and an extension portion 11 that extends in the extension direction different from the opening direction, and at the boundary between the connection portion 20 and the extension portion 11, the joint portion 50 and the connection portion 20 are integrally formed. Even if the orientation of the hollow structure changes midway, since it is seamlessly integrally formed, stress concentration can be suppressed in the region where the orientation of the hollow structure changes. (3) The hollow structure body main body 10 may be narrower than the outer diameter of the joint portion 50. (4) The hollow structure body main body 10 may have a region that gradually widens from the joint portion 50. That is, the root side (joint 50 side) of the hollow structure body main body 10 is tapered and narrower. (5) The hollow structure body main body 10 may have a region that gradually narrows from the joint portion 50. That is, the root side (joint 50 side) of the hollow structure body main body 10 is tapered and wider. (6) A collar is provided in the through holes 55, 56, 57 of the joint portion 50. It may be provided in all of the through holes 55, 56, 57, or may be provided in some of the through holes 55, 56, 57. (7) A reinforcing member may be provided on the joint surface (joint back surface 52) of the joint portion 50. (8) The hollow structure body 10 and the joint portion 50 may be injection molded bodies made of a resin composition. A hollow structure 1 with excellent light weight and desired strength can be realized. (9) The hollow structure body 10 and the joint portion 50 may be cast products made of a metal material. A hollow structure 1 with excellent light weight and desired strength can be realized.

[0042] 1 Hollow structure 10 Hollow structure body 11 Extension portion 20 Connection portion 21 Semi-cylindrical recess 22 Cylindrical recess 50 Joint portion 51 Joint surface 52 Joint back surface 53 Joint opening 55, 56, 57 Through holes

Claims

1. A hollow structure body main body, a joint portion provided on the hollow structure body main body and having a central opening, in a fastening through hole provided in the joint portion, when the hollow structure body main body exists in the opening direction of the through hole, there is a recess extending in the opening direction from the joint portion so as to surround the through hole in a cylindrical shape, the hollow structure body main body, a connecting portion that extends integrally with the joint portion and changes the extending direction from the opening direction of the central opening to a direction different from the opening direction, an extending portion that extends in an extending direction different from the opening direction, and has, at the boundary between the connecting portion and the extending portion, the joint portion and the connecting portion are integrally formed, the recess has a semi-cylindrical recess and a cylindrical recess in the connecting portion, the semi-cylindrical recess is provided in a concave shape toward the opening direction of the first through hole so as to cover the periphery of the first through hole provided at the outer shape boundary of the connecting portion among the through holes in a semi-cylindrical shape, the cylindrical recess is a hollow structure body that covers the periphery of a second through hole provided at a location different from the first through hole among the through holes and where the semi-cylindrical recess does not exist in a cylindrical shape.

2. The hollow structure body according to claim 1, wherein the hollow structure body main body is narrower than the outer diameter of the joint portion.

3. The hollow structure body according to claim 1 or 2, wherein the hollow structure body main body has a region that gradually widens and extends from the joint portion.

4. The hollow structure body according to any one of claims 1 to 3, wherein the hollow structure body main body has a region that gradually narrows and extends from the joint portion.

5. The hollow structure body according to any one of claims 1 to 4, wherein a collar is provided in the through hole of the joint portion.

6. The hollow structure body according to any one of claims 1 to 5, wherein a reinforcing member is provided on the joint surface of the joint portion.

7. The hollow structure body according to any one of claims 1 to 6, wherein the hollow structure body main body and the joint portion are injection molded bodies made of a resin composition.

8. The hollow structure body according to any one of claims 1 to 6, wherein the hollow structure body main body and the joint portion are cast products made of a metal material.

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