Hollow structure

Abstract

To provide a hollow structure capable of reducing braking risk of a connection part to another structure, excellent in lightness, and facilitating accessibility to the inside.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 a side face opening part 30 in an area near a boundary to the joint part 50, facing to an extension direction of the hollow structure body 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In the fields of office furniture, stationery, and industrial equipment, products using hollow frames as components are known. Generally, molded products made of metal materials such as iron-based materials have been used as hollow structures. On the other hand, in order to increase the operating speed and reduce the size of hollow structures such as hollow frames, they are being molded from resin materials to reduce their weight.

[0003] For example, Patent Document 1 discloses a technology for reducing weight by using a link structure made of fiber-reinforced plastic. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-195998 A Summary of the Invention [Problem to be solved by the invention]

[0005] The fiber-reinforced plastic link structure described in Patent Document 1 is a composite body in which the fiber-reinforced plastic and the metal mounting seat are joined by an adhesive such as a urethane adhesive or an epoxy adhesive, or by a joining method that uses the above adhesive in combination with mechanical fastening, and therefore the manufacturing process is complicated. Also, there is a concern that the joint between the fiber-reinforced plastic and the metal mounting seat may be destroyed when transmitting torque from a driving source (e.g., a driving motor).

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a hollow structure that reduces the risk of destruction at the connection parts with other structures, is lightweight, and facilitates access to the inside. [Means for solving the problem]

[0007] [1] According to the present invention, A hollow structural body; a joint portion provided in the hollow structure body and having a central opening; having The hollow structure body has a side opening in a region facing the extension direction of the hollow structure body, the side opening being located near the boundary with the joint portion. A hollow structure is provided. [2] The hollow structure body is a connecting portion that extends integrally from the joint portion and changes an extending direction from an opening direction of the central opening to a direction different from the opening direction; An extension portion extending in the extension direction different from the opening direction; having The hollow structure according to [1] is provided, wherein the side opening is provided in a region of the connecting portion that faces the extending direction of the extending portion. [3] There is provided a hollow structure as described in [2], in which an inner wall surface of the connection portion has a rib extending in the same direction as the extension direction from the vicinity of the side opening. [4] There is provided a hollow structure as described in [3], wherein the ribs are two wall-shaped ribs opposing each other across the side opening and extending to the central opening of the joint portion. [5] There is provided a hollow structure described in any one of [1] to [4], wherein the hollow structure body has a reinforcing wall extending from the joint portion at a position opposite the side opening. [6] Provided is a hollow structure described in any one of [1] to [5], wherein, in a plurality of through holes provided in the joint portion, when the hollow structure main body is present in the opening direction of the through holes, the hollow structure has a recess extending from the joint portion in the opening direction so as to cylindrically surround the through holes. [7] There is provided a hollow structure described in any one of [1] to [6], wherein the hollow structure body has a width narrower than the outer diameter of the joint portion. [8] There is provided a hollow structure described in any one of [1] to [7], wherein the hollow structure body has a region that gradually extends wider from the joint portion. [9] There is provided a hollow structure described in any one of [1] to [7], wherein the hollow structure body has a region that extends from the joint portion and gradually narrows.

[10] There is provided a hollow structure described in any one of [1] to [9], wherein the edge of the side opening on the side of the joint portion is parallel to the surface of the joint portion.

[11] There is provided a hollow structure according to any one of [1] to

[10] , wherein the hollow structure body and the joint portion are injection-molded articles made of a resin composition.

[12] There is provided a hollow structure according to any one of [1] to

[10] , wherein the hollow structure body and the joint portion are castings of a metal material. Effect of the Invention

[0008] According to the present invention, it is possible to provide a hollow structure which is lightweight, reduces the risk of breakage at the connection parts with other structures, and facilitates access to the inside. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing a schematic view of a part of the structure of a hollow structure according to the present embodiment. [Diagram 2] FIG. 2 is a plan view showing a schematic view of a part of the structure of the hollow structure according to the present embodiment. [Diagram 3] FIG. 2 is a front view showing a schematic view of a part of the structure of the hollow structure according to the present embodiment. [Figure 4] FIG. 2 is a bottom view showing a schematic view of a part of the structure of the hollow structure according to the present embodiment. [Diagram 5]FIG. 2 is a left side view showing a schematic view of a part of the structure of the hollow structure according to the present embodiment. [Figure 6] 3 is a right side view showing a schematic view of a part of the structure of the hollow structural body according to the present embodiment, and corresponds to the view seen from the A1 arrow in FIG. 2. FIG. [Figure 7] 3 is a cross-sectional view taken along the line AA in FIG. 2 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all drawings, similar components are given the same reference numerals and the description will be omitted as appropriate. In addition, the drawings are schematic diagrams and do not correspond to the actual dimensional ratio.

[0011] FIG. 1 is a perspective view showing a schematic example of the structure of a hollow structure 1 according to this 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 bottom view of the hollow structure 1. FIG. 5 is a left side view of the hollow structure 1. FIG. 5 is a right side view, corresponding to the view seen in the direction of the arrow A1 in FIG. 2. FIG. 6 is a right side view showing a schematic view of a part of the structure of the hollow structure 1, corresponding to the view seen in the direction of the arrow A1 in FIG. 2. FIG. 7 is a cross-sectional view taken along the line AA in FIG. 2.

[0012] <Outline of hollow structure 1> The hollow structure 1 comprises a hollow structure body 10 and a joint part 50 provided at least on one end of the hollow structure body 10. The hollow structure 1 is used for products in the fields of office furniture, stationery, and industrial equipment. The hollow structure 1 is an injection molded product made of a resin composition or a casting made of a metal material, and the hollow structure body 10 and the joint part 50 are integrally provided. In this embodiment, a joint part 50 is provided at the end of the hollow structure body 10 on the left side as viewed in the drawing, and further, a side opening 30 is provided in a region near the boundary with the joint part 50 and facing the extension direction of the hollow structure body 10. The side opening 30 reduces the risk of destruction of the connection part with other structures (joint part 50, connection part 20, etc.), provides excellent lightness, and facilitates access to the inside of the hollow structure body 10. A specific description will be given below.

[0013] <Hollow structure body 10> The hollow structural 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 extension direction of the extension portion 11 and connects to a joint portion 50. The extension portion 11 and the connection portion 20 are molded in a substantially seamless manner (i.e., without any seams).

[0014] <Extension part 11> The extension 11 is a hollow body (also called a "hollow frame") that has the same diameter and extends linearly to a predetermined length in a cylindrical shape. The thickness of the extension 11 is determined by the required mechanical strength and the material used (i.e., a resin composition, an aluminum alloy, etc.).

[0015] The shape of the extension 11 is not particularly limited as long as it is a structure capable of forming a hollow frame. The extension direction (i.e., axis) may be straight or curved. The cross-sectional shape of the extension 11 in the width direction (direction perpendicular to the extension direction) may be the same or different over the entire region in the extension direction, and may be, for example, a circle, an ellipse, an oval, a semicircle, or a rectangle. In addition, the extension portion 11 is not limited to a configuration in which the outer diameter extends with the same size, but may have a region in which the width gradually increases, or may have a region in which the width gradually decreases. That is, the size of the cross-sectional shape may change. From the viewpoints of the mechanical strength of the hollow structure 1, ease of manufacture, and resistance to stress applied in the short direction, the cross-sectional shape of the extension portion 11 is preferably a circle, an ellipse, or a rectangle.

[0016] <Connection part 20> The connecting portion 20 has a substantially cylindrical shape and has a function of changing the extending direction in a predetermined direction. In this embodiment, the connecting portion 20 is a region of the hollow structure body 10 that covers the upper side of the joint portion 50, and is a region on the left side of a position where a reinforcing wall 40 (see FIG. 7) described later is provided. Specifically, the connection part 20 has a tubular shape that extends vertically upward in the figure so as to cover the joint opening 53, and is curved at the upper end to be continuously connected to the extension part 11. At this part, the connection part 20 changes the opening direction of the joint opening 53 of the joint part 50 by 90 degrees. In the connection part 20, a reinforcing wall 40 is provided at the connection part with the extension part 11. Also, in a region facing the connection part with the extension part 11, i.e., a region facing the reinforcing wall 40 and perpendicular to the upward direction, a side opening 30 that communicates between the inside and outside of the connection part 20 is provided.

[0017] For example, referring to Fig. 3 and Fig. 7, the opening of the joint opening 53 faces upward, but the direction of the extension portion 11, i.e., the extension direction, is changed by the connection portion 20 to face horizontally (to the right in Fig. 3 and Fig. 7). The direction (angle) of the change is not limited to 90 degrees (i.e., horizontal). For example, the direction may be changed to an angle (e.g., 45 degrees) that is diagonally upward in Fig. 3 and Fig. 7, or may be rotated 180 degrees to face downward. When considering injection molding of a resin composition or molding by casting of an aluminum alloy or the like, the change angle is preferably within 90 degrees, taking into account removal from a mold. The shape of the connecting portion 20 may be various shapes, similar to the extending portion 11. However, from the viewpoint of mechanical strength (particularly suppression of stress concentration) and ease of manufacture, it is preferable that the connecting portion 20 has a shape that is substantially the same as and continues from the shape of the extending portion 11.

[0018] <Side opening 30> The side opening 30 is provided in the connecting portion 20 in a region (region in the left direction in the figure) facing the extending direction of the extending portion 11 as described above. Here, the extending direction of the extending portion 11 refers to the linear direction when the extending portion 11 is provided in a straight line. When the extending direction is curved or bent, the extending direction can be the direction of the internal opening of the extending portion 11 at the boundary between the extending portion 11 and the connecting portion 20 (more specifically, the region of the reinforcing wall 40). The side opening 30 has a substantially rectangular shape, for example, as shown in FIG. 5. More specifically, among the edges (sides of the rectangular shape) of the side opening 30, the joint side 31 on the side of the joint portion 50 is provided parallel to the joint surface 51 of the joint portion 50. The two joint opposing side sides 32 are provided perpendicular to the joint side 31 (i.e., the joint surface 51). The protruding side 33 opposing the joint side 31 is provided slightly curved in a convex shape. With this configuration, it is possible to suppress stress concentration in the area close to the connection part with another structure, and to ensure a large side opening 30 for accessing the inside of the hollow structure main body 10. In particular, by providing the joint side 31 in a straight line, it is possible to effectively suppress stress concentration and ensure the area of ​​the side opening 30.

[0019] <Joint part 50> 2, the joint part 50 has a joint opening 53 which is a central opening, and is provided in an annular shape so as to protrude a predetermined width outside the connection part 20 when viewed from above. In other words, it can be said that the hollow structure body 10 has a width narrower than the outer diameter of the joint part 50. Note that a part of the joint part 50 (a part of the right side in FIG. 2) is covered by the connection part 20 and the extension part 11.

[0020] The joint part 50 is provided with a plurality of through holes 55, 56, 57 penetrating the joint front surface 51 and the joint back surface 52. Here, the through holes 55, 56, 57 are provided at a total of 10 locations evenly spaced apart in the circumferential direction. The through holes 55, 56, 57 are used for connection to a driving source such as a motor or other structures (hereinafter referred to as "other structures"). The through holes 55, 56, 57 may be provided with, for example, metal collars.

[0021] In the through holes 55, 56, 57 of the joint part 50, when the connection part 20 and the hollow structure main body 10 of the extension part 11 are present in the opening direction (here, upward direction) of the through holes 55, 56, 57, there are recesses (semi-cylindrical recess 21 and cylindrical recess 22) extending from the joint surface 51 of the joint part 50 in the opening direction (here, upward direction) so as to cylindrically surround the through holes 56, 57.

[0022] The two through holes 56 provided near the outer boundary of the connection part 20 are surrounded by semi-cylindrical recesses 21, which are concave toward the opening direction of the through holes 56. In other words, the semi-cylindrical recesses 21 are provided so as to open a part of the connection part 20 toward the opening direction of the through holes 56.

[0023] With this configuration, even if the through hole 56 provided in the joint part 50 is in a position hidden by the connection part 20, it can be used reliably, and fastening to another structure at the joint part 50 can be performed reliably.

[0024] For the two through holes 57 provided in the region that completely overlaps with the extending portion 11 (the boundary region between the extending portion 11 and the connecting portion 20), the cylindrical recess 22 is provided in a cylindrical shape so as to cover the periphery of the two through holes 57 in a concave shape toward the opening direction of the through holes 57. In other words, the cylindrical recess 22 is provided so as to open a part of the extending portion 11 (the boundary region between the extending portion 11 and the connecting portion 20) in the opening direction of the through holes 57.

[0025] With this configuration, even if the through hole 57 provided in the joint part 50 is in a position hidden by the connection part 20, it can be used reliably, and fastening to another structure can be reliably performed at the joint part 50. Also, as shown in Figures 5 and 7, the two cylindrical recesses 22 are spaced apart, and the interior of the connection part 20 and the interior of the extension part 11 communicate with each other between them, so that sufficient space can be secured even when wiring electric wires or the like inside.

[0026] The joint opening 53 of the joint portion 50 is continuous with the hollow structures of the connection portion 20 and the extension portion 11, and cables such as power lines and signal lines can be passed through the inside of the hollow structure 1. If necessary, a reinforcing member such as a metal plate may be attached to the joint back surface 52 (or joint front surface 51) of the joint portion 50. By providing a 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 another structure, or from being loosened by creep. Examples of the metal plate include aluminum alloys, titanium alloys, copper alloys, magnesium alloys, and stainless steel. As a method for attaching 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 when molding the hollow structure 1 can be used.

[0027] <Internal structure of hollow structure 1> The hollow structural body 10 has, as its internal structure, a reinforcing wall 40 provided in the boundary region between the connection portion 20 and the extension portion 11 , and a rib 70 provided inside the connection portion 20 .

[0028] <Reinforced Wall 40> The reinforcing wall 40 extends from the joint portion 50 to the upper surface of the hollow structure body 10 at a position facing the side opening 30, i.e., in the boundary region between the connection portion 20 and the extension portion 11, so as to close the boundary. A reinforcing wall opening 41 that connects the connection portion 20 and the extension portion 11 is provided near the center of the reinforcing wall 40. The position of the reinforcing wall 40 does not need to be exactly at the boundary between the connection part 20 and the extension part 11, and it may be provided at a position shifted toward the connection part 20 side or the extension part 11 side, or may be provided at multiple locations. With this configuration, the boundary area between the connection part 20 and the extension part 11, where strong stress is thought to act when an external force acts on the hollow structure 1, can be reinforced and strength can be increased. In addition, the reinforcing wall opening 41 ensures communication between the connection part 20 and the extension part 11, making it possible to route cables and the like. In addition, by appropriately setting the size, shape, and number of the reinforcing wall openings 41, it is possible to effectively organize the routing.

[0029] <Rib 70> 4 and 7, the rib 70 has a wall-like rib 70 extending from the vicinity of the side opening 30 inside the connecting portion 20 in the same direction as the extending direction of the extending portion 11. Specifically, the two ribs 70 extend from the inner wall surface near the two joint-opposing sides 32 of the side opening 30 of the connecting portion 20 toward the extending portion 11 (more specifically, the reinforcing wall 40) so as to face each other like a wall. The two ribs 70 separate the joint opening 53 of the joint portion 50 and the inside of the connection portion 20 into three spaces extending in the same direction as the extension direction of the extension portion 11. With this configuration, the connection portion 20 can be reinforced and its strength can be increased. In addition, by appropriately setting the position of the rib 70, the arrangement of the wiring can be effectively organized. An opening may be provided in the rib 70.

[0030] <Materials for hollow structure 1> The hollow structural body 1 is, for example, an injection molded article made of a resin composition or a casting made of a metal material.

[0031] When the resin composition is a thermoplastic resin, the hollow structure 1 can be molded, for example, by injection molding. When the metal material is an aluminum alloy, the hollow structure 1 can be molded, for example, by aluminum die casting. With this configuration, a hollow structure 1 that is lightweight and has the desired strength can be realized. In addition, since the hollow structure 1 is integrally molded, the risk of breakage can be reduced compared to hollow structures with other configurations that use adhesives or the like.

[0032] Examples of aluminum alloys that can pass through a narrow gate with high fluidity include aluminum alloys for die casting, such as ADC1, ADC3, ADC5, ADC6, ADC10, ADC10Z, ADC12, and ADC12Z. In the case where an aluminum alloy is used, the hollow structure 1 can be manufactured under known conditions using a known die-casting machine including, for example, a die having a cavity, an injection sleeve formed in a substantially cylindrical shape having an internal space and communicating with the cavity at one end thereof, and a plunger tip movably disposed within the injection sleeve. A magnesium alloy die-casting product can also be used as the die-casting product.

[0033] When a resin composition (thermoplastic resin) is used, a known method can be used as the injection molding method without any restrictions. That is, the hollow structure 1 can be manufactured, for example, by mounting the above-mentioned metal plate as necessary in a cavity formed between a moving mold and a fixed mold, then injecting and filling a molten thermoplastic resin or a thermoplastic resin composition, then opening the mold, and removing the slides and inserts used as necessary.

[0034] When the hollow structural body 1 is formed by injection molding, the thermoplastic resin as the raw material component is a thermoplastic resin composition that contains a thermoplastic resin as a resin component and further contains additives as necessary. As the thermoplastic resin, one or more thermoplastic resins selected from polyolefin-based resins, polyester-based resins, polyamide-based resins, polyacetal-based resins, polycarbonate-based resins, fluorine-based resins, polyarylene ether-based resins, polyarylene sulfide-based 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-based resins and polyester-based resins are more preferred, and polyamide-based resins are particularly preferred.As a polyamide-containing alloy, an alloy of a polyamide-based resin and a polyarylene ether-based resin can be mentioned as a suitable example.

[0035] 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, polyamide resins obtained from metaxylylenediamine and adipic acid are particularly preferred. Such polyamide resins are called nylon MXD6 and are commercially available, for example, from Mitsubishi Engineering Plastics Corporation under the trade name Reny™.

[0036] The thermoplastic resin composition according to the present embodiment may contain, for example, one or more additives selected from the group consisting of inorganic fillers, flame retardants, flame retardant assistants, heat stabilizers, antioxidants, pigments, weathering agents, plasticizers, dispersants, lubricants, release agents, antistatic agents, impact resistance modifiers, and colorants.

[0037] Examples of inorganic fillers include fibrous fillers (glass fiber, carbon fiber, etc.), powdered granular fillers (kaolin, talc, etc.), and plate-like fillers (mica, etc.). Among these fillers, fibrous fillers, particularly glass fiber (chopped strands, etc.), are preferred because of their high strength and rigidity. These fillers can be used alone or in combination of two or more.

[0038] These fillers may be used in combination with a sizing agent or a surface treatment agent. Examples of such sizing agents or surface treatment agents include functional compounds. Examples of the functional compounds include epoxy compounds, silane compounds, titanate compounds, etc. The amount of the inorganic filler in the thermoplastic resin composition is, for example, 0 to 60% by weight, and preferably 5 to 60% by weight.

[0039] As the flame retardant, known halogen-based flame retardants such as brominated epoxy polymer and decabromodiphenyl ether, and phosphorus-based flame retardants can be used without limitation, but when a polyamide resin is used as the base resin and a color tone other than black is required for the molded product, a halogenated bisimide can be exemplified as a suitable flame retardant. When a flame retardant is used, the content thereof 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.

[0040] In this embodiment, a general colorant can be blended with the resin. Examples of black colorants (black pigments) 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 pigments can be used alone or in combination of two or more kinds.

[0041] In addition, the non-black colorant is other than the black pigment, and includes inorganic pigments and organic pigments described below. 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, yellow lead, titanium yellow, zinc chromate, yellow ocher, yellow iron oxide, etc.), red pigments (e.g., red pigments, amber, red iron oxide, cadmium red, etc.), blue pigments (e.g., Prussian blue, ultramarine, cobalt blue, etc.), and green pigments (e.g., chrome green, etc.).

[0042] Examples of organic pigments include azo pigments, azomethine pigments, methine pigments, indanthrone pigments, anthraquinone pigments, pyranthrone pigments, flavanthrone pigments, benzenethrone pigments, phthalocyanine pigments, quinophthalone pigments, perylene pigments, perinone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, isoindoline pigments, pyrrulepyrrole pigments, and quinacridone pigments.

[0043] The amount of the non-black colorant blended is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 18 parts by mass, and even more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the thermoplastic resin composition.

[0044] In addition to the inorganic filler, flame retardant, and colorant, the thermoplastic resin composition according to the present embodiment may contain 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, release agents, weather resistance improvers, nucleating agents, foaming agents, impact resistance improvers, lubricants, plasticizers, and flow improvers. When other additives are used in combination, the amount of the additives 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.

[0045] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0046] The features of this embodiment are summarized as follows. (1) The hollow structure 1 of this embodiment is A hollow structural body 10; A joint portion 50 is provided in the hollow structure body 10 and has a joint opening 53 (central opening), The hollow structural body 10 has a side opening 30 in a region facing the extension direction of the hollow structural body 10, near the boundary with the joint portion 50. (2) The hollow structural body 10 is a connecting portion 20 that extends integrally from the joint portion 50 and changes its extending direction from the opening direction of the joint opening 53 to a direction different from the opening direction; and an extension portion 11 extending in a direction different from the opening direction thereof, The side opening 30 is provided in a region facing the extending direction of the extending portion 11 of the connecting portion 20 . (3) The inner wall surface of the connection portion 20 has a rib extending from the vicinity of the side opening 30 in the same direction as the extending direction. (4) The ribs 70 are two wall-shaped ribs that face each other across the side opening 30 and extend to the joint opening 53 of the joint portion 50 . (5) The hollow structural body 10 has a reinforcing wall 40 extending from the joint portion 50 at a position opposite the side opening 30 . (6) In the multiple through holes 55, 56, 57 provided in the joint portion 50, when the hollow structure main body 10 (connection portion 20) is present in the opening direction of the through holes 56, 57, the joint portion 50 has recesses (semi-cylindrical recesses 21, cylindrical recesses 22) extending from the joint portion 50 in the opening direction so as to surround the through holes 56, 57 in a cylindrical shape. (7) The width of the hollow structural body 10 is narrower than the outer diameter of the joint portion 50 . (8) The hollow structural body 10 may have a region that extends from the joint portion 50 and gradually becomes wider. (9) The hollow structural body 10 may have a region extending from the joint portion 50 that gradually narrows. (10) Of the edges of the side opening 30, the edge on the joint portion 50 side (joint side edge 31) is provided parallel to the surface of the joint portion 50 (joint surface 51). (11) The hollow structural body 10 and the joint portion 50 may be injection molded articles made of a resin composition. (12) The hollow structural body 10 and the joint portion 50 may be cast products of a metal material.

[0047] 1 Hollow structure 10. Hollow structure body 11 Extension 20 Connection 21 Semi-cylindrical recess 22 Cylindrical recess 30 Side opening 31 Joint side 32 Opposite side of joint 33 Projecting direction edge 40 Reinforced Wall 41 Reinforced wall opening 50 Joint 51 Joint Surface 52 Joint back side 53 Joint opening 55, 56, 57 Through holes 70 Ribs

Claims

1. A hollow structural body; a joint portion provided in the hollow structure body and having a central opening; having the hollow structure body has a side opening in a region facing an extension direction of the hollow structure body, the side opening being located near a boundary with the joint portion, The hollow structural body is a connecting portion that extends integrally from the joint portion and changes an extending direction from an opening direction of the central opening to a direction different from the opening direction; An extension portion extending in the extension direction different from the opening direction; having the side opening is provided in a region of the connecting portion that faces a direction in which the extending portion extends, A hollow structure having a rib extending in the same direction as the extension direction from the vicinity of the side opening on an inner wall surface of the connection portion.

2. The hollow structural body according to claim 1 , wherein the ribs are two wall-like ribs opposing each other across the side opening and extending to a central opening of the joint portion.

3. A hollow structural body, a joint portion provided in the hollow structure body and having a central opening; having the hollow structure body has a side opening in a region facing an extension direction of the hollow structure body, the side opening being located near a boundary with the joint portion, The hollow structure body has a reinforcing wall extending from the joint portion at a position opposite to the side opening.

4. A hollow structural body, a joint portion provided in the hollow structure body and having a central opening; having the hollow structure body has a side opening in a region facing an extension direction of the hollow structure body, the side opening being located near a boundary with the joint portion, A hollow structure in which no other hollow structure is connected to the side opening.

5. A hollow structure as described in any one of claims 1 to 4, wherein, in a plurality of through holes provided in the joint portion, when the hollow structure main body is present in the opening direction of the through holes, the hollow structure has a recess extending from the joint portion in the opening direction so as to cylindrically surround the through holes.

6. The hollow structure according to claim 1 , wherein the hollow structure body has a width narrower than an outer diameter of the joint portion.

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

8. The hollow structure according to claim 1 , wherein the hollow structure body has a region that gradually narrows from the joint portion.

9. The hollow structure according to claim 1 , wherein the edge of the side opening on the side of the joint portion is parallel to a surface of the joint portion.

10. 10. The hollow structure according to claim 1, wherein the hollow structure body and the joint portion are injection molded articles made of a resin composition.

11. 10. The hollow structure according to claim 1, wherein the hollow structure body and the joint portion are cast products of a metal material.

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