JPH0113268Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a resin hollow body that is widely used as a solar heat collector plate in a solar water heater, a heat sink plate in a heating appliance, or a storage tank for various liquids. The present invention relates to an improvement in the structure of a resin hollow body in which a hollow portion is formed by joining resin materials together by molding.

BACKGROUND ART Conventionally, resin hollow bodies used for heat collecting plates, heat dissipating plates, storage tanks, etc. have generally been molded from resin materials such as resin sheets and parisons (resin tubes) by blow molding using split molds. FIG. 1 shows an example of a heat collecting plate 1 manufactured by forming a hollow part by bonding during blow molding. In this figure, a plurality of fluid passages 2 are provided in a heat collecting plate 1 in parallel via non-circulating portions 3, and one end of these fluid passages 2 is communicated with each other through a communication passage 5 having a water supply port 4. , and the other end thereof is communicated with each other through a communication path 7 having a drain port 6.

Further, FIG. 2 shows an example of a resin hollow body used as the large storage tank 11. In this large storage tank 11, the container wall swells or deforms due to the weight of the internal fluid, so in order to prevent this, a joining part 13 is formed in the center of the storage tank 11. A liquid supply port 14 is provided on the top surface.
and a discharge port 16 are provided.

However, in the conventional resin hollow body, for example, in the case of the heat collecting plate 1, as shown in FIG. 3 as a cross-sectional perspective view taken along the line - in FIG. A built-up portion 22 was formed to protrude at a position on the extension of 21. This built-up portion 22 is shown in FIGS. 4A and B.
According to the conventional molding method of a resin hollow body explained by , this was inevitably formed.

That is, as shown in FIGS. 4A and 4B before and after the molding of the resin hollow body, respectively, the resin material 23 such as a resin sheet or parison is heated during molding or in advance to a predetermined state. are crimped and bonded at a predetermined position by the crimping surface 25 of the split mold 24. In addition, during or after this joining, air or liquid may be press-fitted between the resin materials 23, or a through hole 27 may be provided in the groove-shaped concave portion 26 of the split mold 24 and air may be sucked through the through hole 27. Then, insert the resin material 23 into the groove-like concave part 2.
The hollow portion 20 is formed by making a mold. Therefore, since the crimping surface 25 of the split mold 24 is flat, the thickness of the two heated and melted resin materials 23 before molding is different from the thickness of the bonded part 21 after molding the resin hollow body. The excess resin resulting from the difference in thickness caused a build-up inside the hollow portion 20 formed as shown in FIG. 4B, and the build-up portion 22 protruded out.

Also, when molding the storage tank 11, a built-up portion 32 was formed inside the hollow portion 30, as shown in FIG. 5 as a partially cutaway perspective view.

In this way, in the case of the conventional resin hollow body, the built-up portion 2 that is generated when joining the hollow portions 20 and 30 is
2 and 32, the built-up parts 22 and 3 are used in any case where the resin hollow body is used as a heat collecting plate, a heat dissipating plate, a storage tank for various liquids, etc.
Stress is concentrated on 2. Especially the built-up parts 22 and 32
The grooves 28 and 38, which are formed by both side surfaces and the inner wall surfaces of the hollow parts 20 and 30, are prone to cracking due to stress concentration, a so-called notch effect, which reduces the durability of the hollow resin body. Ta. Furthermore, in order to compensate for this decrease in durability, the resin hollow body must be made thick, which is uneconomical. Furthermore, since the width of the crimping surface 25 of the split mold 24 is wide, sufficient crimping strength cannot be obtained and the resin material 23 cannot be sufficiently bonded and molded.

An object of the present invention is to provide a resin hollow body that has excellent durability, high strength, and can be made thinner.

The present invention provides at least one solid protrusion that is formed simultaneously with the formation of the hollow part when the hollow part is formed by bonding resin materials by blow molding using a split mold. The above objective is achieved by providing the joining part along the shape of the edge of the hollow part.

Hereinafter, embodiments of the resin hollow body according to the present invention will be described based on the drawings.

FIG. 6 is a partially cutaway perspective view showing an embodiment in which the resin hollow body according to the present invention is applied to a heat collecting plate. In this embodiment, no built-up part is formed in the hollow part 40, and on both sides of the approximately central part of the joining part 41, the shape of the edge of the hollow part, that is, the longitudinal direction of the hollow part 40 Continuous solid protrusion 4
9 are provided respectively. This protrusion 49
In this case, the thickness of the joint portion 41 protrudes in the thickness direction of the joint portion. In other schematic configurations, the third
There is no difference from the conventional heat collecting plate shown in the figure.

Next, the method for molding the heat collecting plate of this embodiment will be explained with reference to FIGS. 7A and 7B. FIGS. 7A and 7B show the state before and after molding, respectively. In these figures, a recess 59 is provided on the crimp surface 55 of the split mold 54, respectively. Therefore, the crimping surface 55 allows the resin material 2 to
Even if 3 is crimped, as shown in Figure 7B,
As a result of the excess resin generated by the joining flowing into the recess 59, the protrusion 49 is formed, and almost no built-up portion is formed within the hollow portion 40.

Furthermore, as shown in a partially cutaway perspective view in FIG. 8, even in an embodiment in which the resin hollow body according to the present invention is applied to a storage tank, the annular inner edge of the hollow part 60 of the storage tank has a built-up padding. A solid protrusion 69 having the shape of the inner edge of the hollow part, that is, an annular shape, is formed in the joined part 61 by excess resin produced by joining.

According to the embodiment as described above, the hollow portions 40, 6
Since there is no resin build-up inside the 0, stress is concentrated on the build-up when used as a heat collecting plate or storage tank, and there is no possibility of damage due to cracks occurring from there, resulting in excellent durability. It is possible to provide heat collecting plates and storage tanks as resin hollow bodies.

In addition, in these embodiments, the protrusions 49, 6
The size of the concave part of the mold forming the ridge 9 is at least the size of the built-up part formed by protruding into the hollow part 40, 60 that would have been created if these protrusions 49, 69 were not formed. Unless it is 60%, the formation of built-up portions cannot be effectively avoided even if a resin material with a high shrinkage rate upon cooling is used. In addition, the concave angle (indicated by θ in FIG. 9) of the mold concave portion for forming the protrusions 49 and 69 is 20 to 70 degrees, so that the resin can flow quickly during bonding. The above is desirable.

In addition, according to this embodiment as described above, even if the resin hollow body is made thinner, it has enough durability to be used, so it is possible to make the resin hollow body thinner, and it is excellent in economical efficiency such as saving resin materials. This has the effect of not only helping to save resources, but also reducing the weight of the resin hollow body. Furthermore, the protrusions 49, 6
9 is provided along the shape of the edge of the hollow portions 40, 60, the strength of the resin hollow body can be increased.

Furthermore, since the crimp surface of the split mold used for welding is narrowed by the width of the recess 59 etc., a large crimp force can be obtained.
The strength of 61 is improved, and the durability of the resin hollow body is also improved. In addition, even if a large pressure force is applied, the concave part of the mold prevents build-up from occurring, and since the pressure force can be increased in this way, the bonding area 4
It is also possible to narrow the width of 1 and 61, which has the effect of contributing to an improvement in the weight reduction of the resin hollow body.

In addition, in the above-mentioned embodiment, the protruding portions 49 and 69 formed by bonding are different from the bonding portions 41 and 61.
Although the explanation has been given as being provided on both sides of the substantially central portion, it may be provided on only one side.

In addition, when the resin hollow body according to the present invention is used as a heat collecting plate, for example, as shown in FIG. If formed, the strength against stress from the inside and outside of the hollow portion 70 will increase,
Furthermore, even if the internal fluid freezes and expands, the concave portions 72 absorb this, resulting in a heat collecting plate with dramatically improved durability.

As described above, according to the present invention, it is possible to provide a resin hollow body that has excellent durability, high strength, and can be made thin and lightweight.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a resin hollow body as a heat collecting plate, FIG. 2 is a perspective view showing a resin hollow body as a storage tank, FIG. 3 is a cross-sectional perspective view taken along the line - in FIG. Figures 4A and B are enlarged cross-sectional views showing the conventional molding method for resin hollow bodies, and Figure 5 is the - of Figure 2.
FIG. 6 is a partially cutaway perspective view showing an embodiment in which the resin hollow body according to the present invention is applied to a heat collecting plate; FIGS. 7 A and B are cross-sectional views of the resin hollow body according to the present invention. Fig. 8 is a partially cutaway perspective view showing an embodiment in which the resin hollow body according to the present invention is applied to a storage tank, and Fig. 9 illustrates the range of the optimal shape of the protrusion. Cross-sectional view, No. 10
The figure is a sectional view showing another embodiment in which the resin hollow body according to the present invention is applied to a heat collecting plate. 23...Resin material, 40,60,70...Hollow part, 41,61,71...Joining part, 49,69...
... Protrusion portion, 54 ... Split mold, 59 ... Groove-shaped concave portion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A resin hollow body in which resin materials are bonded together and molded by blow molding using a split mold to form a hollow part without a built-up part, the resin material At least one solid protrusion portion is formed in the mutually joined portions so that the flesh of the joined portions protrudes in the thickness direction of the joined portions along the shape of the edge of the hollow portion. A hollow resin body. (2) The resin hollow body according to claim 1 of the utility model registration claim, wherein the protrusion portions are formed to protrude from opposite sides of the joint portion.