JP2001205692A - Hollow dual wall structure and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow dual wall structure which is of superior strength and rigidity with a wall thickness molded uniformly as a whole, even when a reinforcing member is inserted under such a design that the inserted reinforcing member is interposed fixedly and firmly between a front wall and a back wall as well as a manufacturing method for the hollow dual wall structure. SOLUTION: The hollow dual wall structure 1 is formed of the front wall 2, the back wall 3 arranged opposite to the front wall 2, spaced from each other and a peripheral wall 4 forming a hollow part 5 between the front wall 2 and the back wall 3. In the hollow part 5, the reinforcing member 6 is inserted, sandwiched between the front wall 2 and the back wall 3. In addition, a pair of ribs 7, 7 connecting the front wall 2 to the back wall 3 with the reinforcing member 6 sandwiched in between, is formed. The paired ribs 7, 7 are inner ribs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow double-walled structure obtained by blow molding a thermoplastic, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, an inner rib formed in a hollow portion of a plastic hollow double-walled structure constituting an interior wall, a partition, a door of a building, a floor trunk lid of an automobile, a rear parcel shelf, or the like. Japanese Patent Application Laid-Open No. H11-216767 discloses a structure in which strength and rigidity are improved by inserting a flat and curved metal rod into the substrate.

[0003]

Problems to be Solved by the Invention JP-A-11-2
The hollow double-walled structure described in Japanese Patent No. 16767 has been developed by the present applicant, but as a result of a subsequent study, it has been found that there are the following problems mainly in blow molding. Was.

That is, as in a conventional hollow double-wall structure, a metal rod is inserted into a plastic molded body, and a part of the back wall is formed by blow molding so that the outer periphery of the inserted metal rod is formed. Although it is easy to form so that the parison has sufficient thickness, if the parison is thick enough, the part surrounding the metal rod is thinned to obtain the expected strength and rigidity. On the contrary, it is difficult.

Therefore, the present invention is not limited to a configuration in which a part of the parison is wrapped around a tubular or rod-shaped reinforcing member, and only when the reinforcing member is sandwiched between the front wall and the back wall. By forming a pair of ribs connecting the front wall and the back wall across the reinforcing member, the inserted reinforcing member is immovably and firmly interposed between the front wall and the back wall, and the reinforcing member is inserted. It is an object of the present invention to provide a hollow double-walled structure having excellent strength and rigidity, which can be uniformly formed in the entire wall thickness, and a method of manufacturing the same.

[0006]

In order to achieve the above object, a hollow double-walled structure according to claim 1 of the present invention is provided.
A hollow double-walled structure including a front wall, a back wall facing the front wall at an interval, and a peripheral wall forming a hollow portion between the front wall and the back wall, A reinforcing member of a tubular body or a rod-shaped body extends over at least a peripheral wall at one end and is inserted and sandwiched between the front wall and the back wall, and the sandwiching state of the reinforcing member with respect to the front and back walls can be maintained. A pair of ribs for connecting the front wall and the back wall with the reinforcing member interposed therebetween are formed.

According to a second aspect of the present invention, there is provided the hollow double-walled structure according to the first aspect, wherein a pair of ribs connecting the front wall and the back wall with the reinforcing member interposed therebetween are inner ribs. It is characterized by having.

According to a third aspect of the present invention, there is provided a method of manufacturing a hollow double-walled structure, comprising: a front wall; a back wall facing the front wall at an interval; Blow molding a hollow double-walled structure composed of a peripheral wall forming a hollow portion and a mold forming the back wall of the divided molds at one end for blow molding. A pair of slide dies facing each other is provided in the cavity so as to be freely operable, and a reinforcing member of a tubular body or a rod-like body is inserted between the pair of split dies in a space between the pair of slide dies facing each other. Between the pair of split dies, a parison is arranged between the inserted reinforcing member and the cavity of each die to close the pair of split dies. Part of the parison forming the wall is welded to the front wall The slide mold is retracted from the cavity to form a pair of ribs sandwiching the reinforcing member and blow molded, and the reinforcing member is inserted over at least one peripheral wall and sandwiched between the front wall and the back wall. A hollow double-walled structure having a pair of ribs connecting the front wall and the back wall with the reinforcing member interposed therebetween is formed.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a hollow double-walled structure according to the third aspect, wherein the parison disposed between the inserted reinforcing member and the cavity of each mold includes: It is a pair of sheet parisons.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a hollow double-walled structure according to the third aspect, wherein the pair of ribs connecting the front wall and the back wall with the reinforcing member interposed therebetween are formed by: It is characterized in that it is formed into an integral wall-shaped inner rib during blow molding.

[0011]

1 is an overall perspective view of a hollow double-wall structure according to an embodiment of the present invention, FIG. 2 is a perspective view showing details of a main part of FIG. 1, and FIG. FIG. 3 is a partial plan view showing the embodiment.

FIG. 4 is a sectional view of a hollow double-walled structure according to an embodiment of the present invention, showing a blow-molding mode before the mold is closed.
FIG. 5 is a cross-sectional view of a mode in which the slide die has advanced after closing the die, and FIG. 6 is a cross-sectional view of a mode in which the slide die has been retracted and blow-molded.

1 and 2, reference numeral 1 denotes a hollow double-walled structure. The hollow double-walled structure 1 has a panel shape. 2 is the front wall, 3 is the back wall, 4 is the surrounding wall,
The back wall 3 is opposed to the front wall 2 at an interval, and a hollow portion 5 is formed between the front wall 2 and the back wall 3 by the peripheral wall 4.

In the hollow portion 5 of the hollow double-walled structure 1, a tubular reinforcing member 6 is inserted over the peripheral wall 4a at one end and inserted between the front wall 2 and the back wall 3. In addition, a pair of ribs 7 are formed to connect the front wall 2 and the back wall 3 with the reinforcing member 6 interposed therebetween. 8,8
Is a holding joint of the reinforcing member 6. The pair of ribs 7, 7 connecting the front wall 2 and the back wall 3 with the reinforcing member 6 interposed therebetween are inner ribs in which no concave portion appears on the side of the back wall 3 and have an integral wall shape. It should be noted that the outer surface of the back wall 3 has a flat surface with only slight welding marks forming a pair of ribs 7, 7 appearing. The reinforcing member 6 is a metal pipe. In the embodiment shown in FIG. 1, the reinforcing member 6 is formed in the above-described manner so as to form a pair with the peripheral wall 4a at one end and the peripheral wall 4b at the other end.
And ribs 7, 7 are formed.

The hollow double-walled structure 1 according to the present invention may have a structure in which the reinforcing member 6 is inserted in a series between the opposing peripheral walls 4a and 4b. The reinforcing member 6 in this case is preferably a straight metal pipe. In the configuration in this case, a pair of ribs 7,
The reinforcement member 7 can be formed so as to correspond to substantially the entire length of the reinforcing member 6, or can be formed to partially correspond at appropriate intervals in addition to both end portions.

In the embodiment shown in FIGS. 1 and 2, a pipe having a circular cross section is exemplified as the reinforcing member 6, but the reinforcing member 6 is not limited to this. It may be a polygonal cylinder or an elliptical cylinder, or a solid cylinder.

The hollow double-walled structure 1 according to the present invention comprises AB
S resin, modified polyphenylene oxide resin, polycarbonate resin, polyamide resin, polypropylene resin,
It is made of a blowable thermoplastic resin such as polyethylene resin.

In the hollow double-wall structure 1 according to the present invention, even when the reinforcing member 6 is merely sandwiched between the front wall 2 and the back wall 3, the front wall 2 and the back wall are sandwiched by the reinforcing member 6. By forming a pair of ribs 7, 7 connecting the walls 3, the inserted reinforcing member 6 is immovably and firmly interposed between the front wall 2 and the back wall 3, and the reinforcing member Even if 6 is inserted, a part of the back wall 3 does not become thin and the whole wall thickness is not formed uniformly, so that the strength and rigidity are excellent.

Another embodiment shown in FIG.
Is bent into a hook shape, and a pair of ribs 7,
7 is along the bent shape of the reinforcing member 6. The hollow double-wall structure 1 shown in FIG. 3 is suitable, for example, as a bed protection frame.

As the hollow double-walled structure 1 according to the present invention, in addition to the illustrated embodiment, the hollow double-walled structure 1
A reinforcing member having a U-shape may be inserted into the longitudinal peripheral wall so that both ends protrude. This configuration is suitable for use in a stable standing posture as a shelf fall prevention frame or a bed protection frame.

The hollow double-wall structure 1 according to the present invention is shown in FIG.
Or blow molding as shown in FIG. 9 is the front wall 2
Is a second split mold for forming the back wall 3, and a pair of slide dies 11, 11 is inserted into the cavity at an interval in the other split mold 10. The recesses 12 and 12 corresponding to the reinforcing members 6 to be inserted respectively are formed in the cavities of one of the divided molds 9 and the other of the divided molds 10 for forming the front wall 2 so as to be capable of retreating. . 13 and 14 are a pair of sheet parisons.

In the blow molding of the hollow double-wall structure 1 according to the present invention, as shown in FIG. The reinforcing members 6 are inserted, and the parisons 13 and 14 are arranged between the inserted reinforcing members 6 and the cavities of the respective dies between the pair of divided dies 9 and 10.

Next, as shown in FIG. 5, the pair of split dies 9 and 10 are closed, and the pair of slide dies 11 and 11 are first advanced out of the cavity to form the back wall 3.
4 is welded to a parison 13 forming the front wall 2, and as shown in FIG. 6, the slide dies 11, 11 are retracted from the cavity and blow-molded to form a pair of ribs 7 sandwiching the reinforcing member 6. , 7 are formed.

As shown in FIG. 6, the pair of ribs 7, 7 formed by blow molding after retreating the slide dies 11, 11 are pressed into their concave shapes to be formed into an integral wall. This is an inner rib in which no concave shape appears on the back wall.

[0025]

According to the present invention, the parison has a structure in which a part of the parison is not wrapped around the tubular or rod-shaped reinforcing member, but only the reinforcing member is sandwiched between the front wall and the back wall. Also, by forming a pair of ribs connecting the front wall and the back wall across the reinforcing member, the inserted reinforcing member is immovably and firmly interposed between the front wall and the back wall, and the reinforcing member A hollow double-walled structure having excellent strength and rigidity and a method of manufacturing the same can be provided even if the wall is inserted.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a hollow double-wall structure according to an embodiment of the present invention.

FIG. 2 is a perspective view showing details of a main part of FIG. 1;

FIG. 3 is a partial plan view showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a hollow double-walled structure according to an embodiment of the present invention, showing a blow molding mode before closing the mold.

FIG. 5 is a cross-sectional view showing a blow molding mode of the hollow double-walled structure according to the embodiment of the present invention, in which the slide mold is advanced after closing the mold.

FIG. 6 is a cross-sectional view showing a blow-molding mode of the hollow double-walled structure according to the embodiment of the present invention, in which the slide mold is retracted and blow-molded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow double wall structure 2 Front wall 3 Back wall 4 Peripheral wall 4a Peripheral wall at one end 4b Peripheral wall at the other end 5 Hollow part 6 Reinforcement member 7,7 Rib 8,8 Clamping joint part 9,10 A pair of split metal Mold 11, 11 A pair of slide molds 12, 12, A recess 13, 14 A pair of sheet parisons

Claims (5)

[Claims] 1. A hollow double-walled structure comprising a front wall, a back wall facing the front wall at an interval, and a peripheral wall forming a hollow portion between the front wall and the back wall. In addition, in the hollow portion, a reinforcing member of a tubular body or a rod-like body is inserted into at least one peripheral wall while being sandwiched between the front wall and the back wall, and the reinforcing member is sandwiched between the front wall and the back wall. A pair of ribs connecting between the front wall and the back wall with the reinforcing member interposed therebetween so as to maintain the height of the hollow member. 2. The hollow double-wall structure according to claim 1, wherein the pair of ribs connecting the front wall and the back wall across the reinforcing member are inner ribs. 3. A hollow double-walled structure comprising a front wall, a back wall facing the front wall at an interval, and a peripheral wall forming a hollow portion between the front wall and the back wall. In a method of blow molding, a mold forming a back wall of a pair of split molds for blow molding is provided with a pair of slide molds facing each other at an interval so as to be able to freely move in and out of a cavity. A tubular or rod-shaped reinforcing member is inserted between the pair of split molds at opposing intervals of the pair of slide dies, and the inserted reinforcing member and the cavity of each mold are inserted between the pair of split dies. A pair of split dies is closed by placing a parison between them, and a pair of slide dies are first advanced out of the cavity, and a part of the parison that forms the back wall is welded to the front wall, and then the slide dies are removed. Retract from the cavity and sandwich a pair of reinforcing members A rib is formed and blow-molded so that the reinforcing member covers at least one peripheral wall and is inserted and inserted between the front and back walls, and connects the front and back walls with the reinforcing member interposed therebetween. Forming a hollow double-walled structure having a pair of ribs formed thereon. 4. The method according to claim 3, wherein the parison disposed between the inserted reinforcing member and the cavity of each mold is a pair of sheet parisons. . 5. The hollow double wall according to claim 3, wherein the pair of ribs connecting the front wall and the back wall with the reinforcing member interposed therebetween are formed into an integral inner rib at the time of blow molding. The method of manufacturing the structure.