JP7708573B2 - hollow structure - Google Patents

Description

The present invention relates to a hollow structure.

In the fields of office furniture, stationery, building materials, and industrial equipment, products that use hollow frames as components are known. Generally, molded products made of metal materials such as iron-based materials have been used as hollow structures. However, in order to increase the operating speed and reduce the size of hollow structures such as hollow frames, they are being made into molded products made of resin materials to reduce their weight. As the range of use expands, efforts are also being made to strengthen the bonding strength with other structures.

For example, Patent Document 1 discloses a technology that reduces weight by using a link structure made of fiber-reinforced plastic.

JP 2009-195998 A

However, the joint structure of the fiber-reinforced plastic link structure described in Patent Document 1 is a composite in which the fiber-reinforced plastic and the metal mounting seat are joined using an adhesive such as a urethane adhesive or an epoxy adhesive, or a joining method that uses the above adhesive in combination with mechanical fastening, making the manufacturing process complicated, and there was a demand for technology that could manufacture hollow structures with fewer manufacturing steps.

The present invention was made in consideration of the above circumstances, and aims to provide a technology that realizes a hollow structure as a hollow frame with excellent light weight with fewer manufacturing steps.

According to the present invention, there is provided a hollow structural body,
A connecting portion that is integrally provided at least one end of the hollow structure body and is connected to another member;
having
The connecting portion is
A connecting portion body integrally provided so as to connect the hollow structure body and the hollow structure;
a fastening portion provided to close an opening at an end of the hollow structure and fastened to another member;
A hollow structure is provided having the following structure:

The present invention provides a technology that can realize a hollow structure as a lightweight hollow frame with fewer manufacturing steps.

FIG. 1 is a perspective view showing a schematic example of a structure of a blow molded part according to an embodiment of the present invention. FIG. 2 is a perspective view showing a schematic example of the structure of a blown molded part according to the present embodiment, the view showing an example of the structure of a blown molded part in which an opening is fitted and closed with a resin cap. 2 is a perspective view showing the structure of the blow molded part shown in FIG. 1 when a cross section passing through point P in the figure is cut perpendicular to the longitudinal direction and viewed from the y-axis direction. 4 is a perspective view showing a structure in which a resin cap is fitted and closed on the cross-sectional structure of the blown molded part shown in FIG. 3 . 2 is a diagram showing the structure of the blow molded part shown in FIG. 1 when viewed from the S direction (x-axis). FIG.

Below, 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 descriptions will be omitted where appropriate. The drawings are schematic and do not correspond to the actual dimensional ratios. The symbol "~" between numbers in the text means "above" to "below" unless otherwise specified.

<Outline of hollow structure 1>
FIG. 1 is a perspective view showing a schematic example of the structure of a hollow structure 1. As shown in FIG.
The hollow structure 1 (also referred to as a "hollow molded part" or "hollow frame") comprises a hollow structure body 1a and a connecting portion 1b provided at least at one end of the hollow structure body 1a. The hollow structure body 1a and the connecting portion 1b are molded from a thermoplastic resin or a light metal alloy (including light metal). That is, the hollow structure body 1a and the connecting portion 1b are molded seamlessly (without joints).
The hollow structure body 1a has, for example, a pipe shape.
The connecting portion 1b may be provided at one end of the hollow structure body 1a, or at both ends as shown in the figure.

When the hollow structural body 1a and the connecting portion 1b are made of a thermoplastic resin, the hollow structural body 1a and the connecting portion 1b can be molded, for example, by injection molding.
When the hollow structural body 1a and the connecting portion 1b are made of a light metal alloy, the hollow structural body 1a and the connecting portion 1b can be formed by a die casting method.

The hollow structure 1 has excellent light weight because the hollow structure body 1a and the connecting portions 1b are made of a lightweight thermoplastic resin or a light metal alloy.
Furthermore, the hollow structure 1 has the hollow structure body 1a and the connecting portion 1b molded seamlessly. In other words, the hollow structure 1 having the hollow structure body 1a and the connecting portions 1b at both ends can be manufactured with fewer manufacturing steps, more specifically, in one molding operation. Also, compared to conventional hollow molded parts using adhesives, the risk of destruction of the hollow structure body 1a and the connecting portion 1b can be reduced.
As described above, according to this embodiment, the risk of breakage between the hollow structure body 1a and the connecting portion 1b is reduced, and a hollow structure 1 having excellent lightweight properties can be provided.

<Hollow structural body 1a>
The shape of the hollow structure body 1a is not particularly limited as long as it is a structure capable of forming a hollow frame structure, but for example, the axis is a straight line, and the cross-sectional shape in the short side direction of the hollow structure body 1a may be the same or different, for example, a circle, an ellipse, an oval shape, a semicircle, or a rectangle. 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, but if it is different, it is desirable that the cross-sectional shape is smallest at the midpoint in the longitudinal direction of the hollow structure body 1a and largest at both ends of the hollow structure body 1a. In other words, it is preferable that the cross-sectional shape in the short side direction of the hollow structure body 1a is largest at both ends of the hollow structure body 1a. By making it into such a shape, the appearance becomes a smart structure and contributes to reducing the weight of the entire hollow structure 1. In this embodiment, the phrase "the size of the cross section at point A is larger than the size of the cross section at point B" is defined as the cross section forming frame at point B being completely contained within the cross section forming frame at point A when viewed directly along the axis from the longitudinal direction, and it should be noted that this is not determined simply by comparing the cross section areas of points A and B. From the viewpoints of the mechanical strength and ease of manufacture of the hollow structure 1, and resistance to stress applied in the short direction, the cross section shape of the hollow structure main body 1a is preferably circular, oval, or rectangular. Figures 1 to 5 show examples of hollow molded parts in which the cross section of the hollow structure main body 1a is rectangular.

<Connection part 1b>
The connecting portion 1b has a connecting portion main body 1c that is integrally provided with the hollow structure main body 1a so as to connect the hollow structure, and a fastening portion 3 that is provided to close the opening at the end of the hollow structure and is fastened to another member. The fastening portion 3 has a substantially annular shape. The connecting portion main body 1c extends cylindrically from the substantially annular outer periphery of the fastening portion 3, and is continuously connected to the hollow structure main body 1a at the cylindrical side. In this embodiment, the outer diameter of the fastening portion 3 is narrower than the width of the hollow structure main body 1a in the short direction, but it may be the same.

When the hollow structure 1 rotates around the connecting portion 1b (more specifically, the fastening portion 3), a fastening portion 3 having a rotation center axis 3b is formed at the connecting portion 1b. When the fastening portions 3 for connection are located at both ends of the hollow structure body 1a, it is more preferable from a manufacturing standpoint that the two rotation center axes 3b are parallel to each other with respect to the axis.

<Fastening part 3>
The fastening portion 3 has a disk-like shape, and more specifically, is annular in shape with openings provided inside the hollow structure 1 for passing cables such as power lines and signal lines.
The fastening portion 3 preferably has a plurality of screw holes 3a (through holes) for fastening another structure (attached member). The number of screw holes 3a is not particularly limited, but is usually 5 to 20, and preferably 8 to 15. The plurality of screw holes 3a are preferably provided at predetermined intervals in the circumferential direction of the disk-shaped fastening portion 3. In this case, the plurality of screw holes 3a are preferably provided at equal intervals.

A metal plate may be attached to the bottom surface (outer surface) of the fastening portion 3 as necessary. By disposing the metal plate, it may function as a seat surface for the mounting screw, and loosening of the mounting screw may be prevented. Examples of metal plates include aluminum alloys, titanium alloys, copper alloys, magnesium alloys, stainless steel, etc. In addition, as a method for attaching 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 when molding the hollow structure 1 is preferably used. When the material of the hollow structure 1 is a thermoplastic resin as described below, it is preferable to form a fine uneven structure on the surface of the metal plate by surface treatment of the metal plate, and to injection mold the thermoplastic resin into the metal plate so that the surface with the fine uneven structure becomes the attachment surface side.

The fastening portion 3 is provided inside the connecting portion 1b. In other words, it does not protrude outward from the connecting portion main body 1c in a flange-like manner. With this configuration, when the hollow structure 1 is attached to another structure, the fastening portion 3 is not visible from the outside, meaning that the screw holes 3a and the screws used for fastening can be hidden. This can improve the design of the hollow structure 1. It also eliminates the risk of snagging due to the shape of the screw holes 3a and the screws used for fastening, and avoids the trouble of having to prepare covers to cover them.

<Opening 2>
Fig. 2 is a perspective view showing a schematic example of the structure of the hollow structure 1, and is a diagram 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 on the cross-sectional structure of the hollow structure 1 shown in Fig. 3.

The connecting portion 1b has an opening 2 that communicates between the inside and outside of the hollow structure 1. The opening 2 is used to perform various operations, such as aligning the cable assembly inside the fastening portion 3 and fixing it, or passing a male screw through a screw hole provided in the fastening portion 3 and fastening it with a female screw.

The size of the opening 2 is not particularly limited, but is preferably designed so that when the hollow structure 1 is viewed in the longitudinal direction (e.g., the S direction in Figure 1), the area (A1) within the frame line X1 formed by the innermost wall of the hollow structure main body 1a is usually 50 to 100 area %, preferably 60 to 95 area %, and more preferably 65 to 90 area % of the area (A0) within the frame line X2 formed by the opening 2 (see Figure 5). In Figure 5, the A1/A0 value is about 73 area %.

By making the opening shape large enough to meet these requirements, the efficiency of various tasks performed through the opening 2 can be improved, and the hollow structure 1 can also be efficiently removed from a mold when being molded, for example, by injection molding.

When no work is being performed, the opening 2 may be closed by, for example, a removable cap 4 to prevent the ingress of foreign matter such as dust, to prevent water ingress when the opening is submerged, and to prevent accidents such as getting workers' clothes caught in the opening. There are no particular limitations on the method of closing the opening, but any method of fitting that allows for free locking and unlocking can be used without limitation. For example, mechanical fastening methods using screws and snap-fitting, which is a fastening method that does not use screws, are also preferably used. In a snap-fit, a claw portion is formed on one of the members that constitute the product, and a fixing portion into which the claw portion fits, i.e., a claw locking portion, is provided at the opposing position of the other member, which is the mating member. A structure such as a housing made of multiple members is assembled into one by connecting and fixing the claw portion and the claw locking portion of each member. A snap-fit has the advantage of making it easier to assemble the structure without drilling holes in the members.

<Material of Hollow Structure 1>
The hollow structure body 1a and connecting portion 1b constituting the hollow structure 1 are each made of at least one material selected from thermoplastic resins and light metal alloys, with thermoplastic resins being preferred from the viewpoint of further improving the lightweight nature of the hollow structure 1.
One of the key features of this embodiment is that the hollow structure 1 is seamlessly molded, and the hollow structure 1 is formed, for example, by a die casting method using a light metal alloy or a thermoplastic resin injection molding method. Among these molding methods, the injection molding method using a thermoplastic resin is preferred from the viewpoint of improving the light weight of the entire hollow structure 1.

Examples of the aluminum alloy of the light metal alloy include aluminum alloys for die casting, such as ADC1, ADC3, ADC5, ADC6, ADC10, ADC10Z, ADC12, and ADC12Z, from the viewpoint of passing through a narrow gate with high fluidity. Examples of the magnesium alloy include AZ91 and AM60.
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 that includes, for example, a mold having a cavity, an injection sleeve that is formed in an approximately cylindrical shape so as to have an internal space and communicates with the cavity at one end thereof, and a plunger tip that is movably arranged within the injection sleeve.

On the other hand, known injection molding methods can be used without restriction. That is, when the hollow structure 1 is made of a thermoplastic resin, the hollow structure 1 can be manufactured, for example, by mounting the above-mentioned metal plate as necessary in a cavity formed between a movable mold and a fixed mold, then injecting and filling the cavity with a molten thermoplastic resin or a thermoplastic resin composition, then opening the mold, and removing the slides and inserts used as necessary.

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.

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 TM.

The thermoplastic resin composition may contain 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 modifiers, and colorants.

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.

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.

As the flame retardant, known halogen-based flame retardants such as brominated epoxy polymers and decabromodiphenyl ether, as well as phosphorus-based flame retardants, can be used without restrictions, 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 used as an example of a suitable flame retardant. When a flame retardant is used, the 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.

In this embodiment, a general colorant can be blended with the resin. Examples of black colorants (black pigments) that can be used include carbon black, graphite, titanium black, black iron oxide, and the like. Of 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 types.

Non-black colorants include inorganic pigments and organic pigments other than the black pigments described above. 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.), green pigments (e.g., chrome green, etc.), etc.

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,
Examples of the isoindolinone type, the isoindoline type, the pyrrule-pyrrole type, the quinacridone type, and the like are mentioned.

The 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 even more preferably 0.5 to 15 parts by mass per 100 parts by mass of the thermoplastic resin composition.

In addition to the inorganic filler, flame retardant, and colorant, other additives may be blended into the thermoplastic resin composition as long as they do 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 blended is, for example, 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass, per 100 parts by mass of the resin composition.

<Materials for Cap 4>
As a material for forming the cap 4, various materials such as resin, light metal alloy, wood, etc. can be used. In the case of a material such as resin or light metal alloy, the cap 4 may be made of the same material as the hollow structure body 1a or may be made of a different material.
When the cap 4 is made of resin, the thermoplastic resin or thermoplastic resin composition for manufacturing the hollow structure 1 can be used as the resin without any restrictions. That is, polyamide-based resins and polyester-based resins are more preferable, and polyamide-based resins are particularly preferable, as the resin constituting the cap 4. The cap 4 can be molded using known molding methods such as injection molding, extrusion molding, vacuum molding, blow molding, pressure molding, and compression molding, and molding using injection molding and extrusion molding is preferable in terms of productivity.

The above describes the embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

The features of this embodiment are summarized as follows.
[1] The hollow structure 1 is
A hollow structural body 1a,
A connecting portion 1b is provided integrally with at least one end of the hollow structure body 1a and is connected to another member;
having
The connecting portion 1b is
A connecting portion body 1c is provided integrally with the hollow structure body 1a so as to connect the hollow structure,
A fastening portion 3 that is provided to close an opening at an end of the hollow structure and is fastened to another member;
has.
[2] The fastening portion 3 has a substantially annular shape,
The connecting portion main body 1c is provided extending from the substantially annular outer shell.
[3] The connecting portion body 1c has an opening 2.
[4] A cap 4 (lid portion) is 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 and used for connecting to the other member.
[6] The cross-sectional shape of the hollow structural body 1a perpendicular to the extending direction is circular, elliptical, oval, semicircular or rectangular.
[7] The hollow structural body 1a and the connecting portion 3 may be made of a thermoplastic resin.
[8] The hollow structural body 1a and the connecting portion 3 may be made of a light metal or a light metal alloy.

REFERENCE SIGNS LIST 1 Hollow structure 1a Frame body 1b Connection part 1c Connection part body 2 Opening 3 Fastening part 3a Screw hole 3b Rotation center axis 4 Cap X1 Frame line formed by the innermost periphery of the hollow structure body X2 Frame line formed by the opening

Claims (6)

a hollow structural body extending in a longitudinal direction ;
A connecting portion that is integrally provided at least one end of the hollow structure body and is connected to another member;
having
The connecting portion is
A connecting portion body provided so that the hollow structure body and the hollow structure are continuous;
A fastening portion that is fastened to another member,
The fastening portion has an annular shape with an opening at its center,
An outer shell of the coupling portion body extends from a part of the annular outer shell,
The coupling body has an opening,
When viewed from the longitudinal direction of the hollow structure body, a first frame line formed by an innermost wall of the hollow structure body is located inside a second frame line formed by the opening,
A hollow structure , wherein the area of the region surrounded by the first frame line is 50 to 100% of the area of the region surrounded by the second frame line . The hollow structure according to claim 1, which has a lid that is removably fitted into the opening. The hollow structure according to claim 1 or 2 , wherein the fastening portion has a plurality of through holes provided at predetermined intervals in the circumferential direction and used for connecting to the other member. 4. The hollow structure according to claim 1 , wherein the cross section of the hollow structure body perpendicular to the extending direction is circular, elliptical, oval, semicircular or rectangular. The hollow structure according to claim 1 , wherein the hollow structure body and the connecting portion are made of a thermoplastic resin. 5. The hollow structure according to claim 1 , wherein the hollow structure body and the connecting portion are made of a light metal or a light metal alloy.