JPH06218735A - Resin core - Google Patents

Abstract

PURPOSE:To provide a lightweight thin-walled resin core having high rigidity, the high degree of freedom of designing and capable of being shortened in the dissolving time liquid. CONSTITUTION:A resin core 1 is constituted of divided shells 3a, 3b composed of a resin material dissolved in a liquid such as a hot water and a plurality of ribs 5, 6 are provided to the inner surfaces of the divided shells 3a, 3b so as to provide intervals in the longitudinal direction of the shells and, in such a state that spheres 4 are received in the spaces between the ribs 5,6, the divided shells 3a, 3b are fixed to form a hollow core main body 3 having a plurality of the spheres 4 arranged therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin core which is soluble in a liquid.

[0002]

2. Description of the Related Art Conventionally, resin hollow bodies having complicated shapes, such as pipes such as intake manifolds and housings having water channels, for automobile engine parts have a hollow structure obtained by blow molding of a thermoplastic resin. It is manufactured by using a core, forming a resin on the outside of the core arranged in the mold by injection molding or the like, and then eluting the core to hollow the core. To elute such a core, when the core is made of a resin that dissolves in a liquid, for example, a water-soluble resin, hot water or the like is sprayed toward the core after molding the resin product, The method of melting and discharging the core is adopted. Therefore, in order to shorten the elution time of the core, the core needs to be formed as thin as possible.

However, as shown in FIG. 14, when the resin product 51 is injection-molded with the resin 51a, several hundreds are formed on the surface of the core 54 arranged in the upper and lower molds 52 and 53 during the molding process. Since a pressure of kgf / cm ² is applied, if the thickness of the core 54 is thin, the core 54 may be deformed and destroyed. On the other hand, in order to prevent such damage of the core 54 and reduce the amount of deformation of the core 54, there is a method of forming the core 54 with a sufficiently thick wall or a solid structure. According to the core 5
4 has a problem that the elution time is long and the amount of the core material used is large.

Therefore, various methods for reinforcing the core 54 have been conventionally proposed. For example, the core 54 of the hollow structure
A method has been adopted in which a powder filling material such as sand or metal powder is placed in the inside, and the core 54 is reinforced by the powder filling material.

[0005]

However, in the above-mentioned conventional reinforcing method, the core 54 is made of the resin product 51.
Since it is integrated with the core 54, the weight of the core 54 becomes very large, and the handling is complicated and the workability is poor. In addition, by adding a filler to the core material,
However, considering the solubility of the core material in a liquid and the balance of the system for recycling, it is impossible to reinforce the core material excessively.

The present invention has been made in view of the above circumstances, and its purpose is to reduce the time taken to dissolve in a liquid while having a small thickness, a light weight, a high rigidity, a large degree of design freedom. An object is to provide a resin core that can be made.

[0007]

In order to solve the above-mentioned problems of the prior art, in the present invention, a split shell is formed of a resin material that dissolves in a liquid, and a plurality of ribs are formed on the inner wall surface of the split shell. Spaced in the longitudinal direction,
A plurality of spherical bodies are arranged inside the core body by forming the hollow core body by fixing the divided shells with the spherical body placed between the ribs.

[0008]

In the resin core according to the present invention, a split shell is formed of a resin material that is soluble in a liquid, and a plurality of ribs are provided on the inner wall surface of the split shell at intervals in the longitudinal direction, and between the ribs. A rib that enhances the reinforcing effect because it is composed of a hollow core body formed by fixing split shells in a spherical body and a plurality of spherical bodies arranged inside the core body. And the presence of the spherical body makes it possible to withstand the pressure during resin molding sufficiently even if the core body is made thin, and as a result, the elution time can be shortened and the amount of core material used can be reduced. It Moreover, since the spherical body disposed inside the core body has a ball shape,
When the core elutes, it moves smoothly inside the resin product and is quickly discharged to the outside.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

1 to 12 show an embodiment of a resin core according to the present invention. In the figure, 1 is a water-soluble resin that is soluble in a liquid, for example water (for example, Swiss BELLA
A substantially cylindrical (hollow) resin core 2 formed by ND's GBC-1330, etc., 2 is a resin product that is a resin hollow body having a complicated shape, and this resin product 2 is the resin core. 1 to be manufactured.

The resin-made core 1 is composed of a core body 3 having a hollow structure and a plurality of spherical bodies 4 arranged inside the core body 3. As shown in FIG. 1 and FIG. 2, the core body 3 faces the inner wall surfaces of the split shells (half shells) 3a, 3b, which are made of the above-mentioned water-soluble resin material and have a substantially semicircular cross section, facing each other. It is manufactured by welding or adhering in this state.

Therefore, these split shells 3a, 3b
Is integrally formed by blow molding,
The inner wall surface has a plurality of ribs 5 as shown in FIG. 3 or 4.
6 are provided at regular intervals along the longitudinal direction. These ribs 5 and 6 are provided to prevent the spherical body 4 from freely moving inside the core body 3, and the split shells 3a and 3b are fixed to assemble the core body 3. In this state, they are arranged so as to face each other.

On the other hand, the spherical body 4 has an outer diameter of the core body 3
Is formed within the minimum thickness of the split shell 3
When the a and 3b are fixed, they are placed between the ribs 5 and 6 and arranged inside the core body 3. The plurality of spherical bodies 4 may be installed only in a portion requiring reinforcement of the core body 3 in accordance with the pressure distribution during injection molding of the resin product 2, or may be installed in the entire core body 3. It is also possible.

As the material of the spherical body 4, aluminum, steel, glass fiber reinforced resin, ceramics or the like which is free from rust and has a small deformation capable of withstanding several tens of kgf / mm ² stress can be considered. If these spherical bodies 4 are formed in a ball shape, they may have a hollow structure as shown in FIG. 5 or a solid structure as shown in FIG. It is configured to roll around inside and be discharged to the outside. Moreover, the spherical body 4 having a hollow structure can be assembled by fixing the hemispherical bodies 4a and 4b as shown in FIGS. 6 and 7. In addition, as shown in FIG. 9, the spherical body 4 having a solid structure may be assembled by fixing hemispherical bodies 4a and 4b, or as shown in FIG.
It is also possible to attach and fix b, 4c, and 4d. In the case of the metallic spherical body 4, it is possible to generate heat by electromagnetic induction heating.

To manufacture the resin product 2, the resin core 1 is used.
Besides, a pair of upper and lower molds 7, 8, a pipe 10 for injecting hot water 9, and a container 11 for accommodating the eluted core body 3
Then, the net plate 12 or the like that receives the spherical body 4 discharged from the resin product 2 is used. Then, recesses 13 and 14 corresponding to the shapes of the resin product 2 and the core body 3 are formed on the lower surface 7a of the upper mold 7 and the upper surface 8a of the lower mold 8, respectively. A passage 15 for the resin 2a for molding the resin product 2 is provided inside the container along the up-down direction.

In order to manufacture the resin product 2 using the resin core 1 constructed as described above, first the divided shell 3
A spherical body 4 is inserted between the ribs 5 and 6 of a and 3b, respectively, and in this state, the divided shells 3a and 3b are fixed to form a core body 3 having a hollow structure. The resin core 1 reinforced by disposing the individual spherical bodies 4 is assembled. Next, the resin core 1 is set in the recesses 13 and 14 of the upper and lower molds 7 and 8 to set the upper and lower molds 7 and 8.
Is closed, and in this state, the resin product 2a is molded by injection molding or the like to fill the outside of the core body 3 with the resin 2a such as thermoplastic resin via the passage 15 (see FIG. 11). After that, the upper and lower molds 7 and 8 are released, the resin core 1 and the resin product 2 are taken out from the upper and lower molds 7 and 8, the core body 3 is eluted, and the spherical bodies 4 are discharged. Then, only the resin product 2 is obtained.

In order to elute the core body 3,
As shown in FIG. 12, the hot water 9 is jetted from the pipe 10,
The warm water 9 is poured on the resin core 1. Then, the core body 3
Is dissolved in the warm water 9, is discharged from the inside of the resin product 2, and is housed in the container 11. At this time, the ribs 5 and 6 of the split shells 3a and 3b forming the core body 3 are also melted, so that the spherical body 4 rolls inside the resin product 2 and is discharged from the inside of the resin product 2 to the outside. Net plate 12
Fall on. Therefore, the melted core body 3 and the spherical body 4 are collected in a state of being separated from each other.

For example, in the case of a three-cylinder 1.0-liter engine intake manifold, when a conventional resin core is molded with a solid structure, it is 2 to 2.5 kg, 1300.
Since it is up to 2000 cc, it takes 1.5 to 2.5 before the core is eluted from the resin product even if hot water at 95 ° C is applied.
It took time. On the other hand, the resin core 1 of the present embodiment
If 30 aluminum spherical bodies 4 are provided inside the core, the amount of resin used to mold the core body 3 is reduced to about 1/3 of the conventional one due to the thinning, and 95 ° The elution time of C with hot water was shortened to 10 minutes in consideration of the heating effect of the aluminum spherical body 4.

In the resin-made core 1 of this embodiment, the divided shells 3a and 3b provided with a plurality of ribs 5 and 6 are fixed to form the core body 3, and the inside of the core body 3 is formed. Since a plurality of spherical bodies 4 are disposed in the core body 3 and the core body 3 that dissolves in warm water is reinforced from the inside by the plurality of ribs 5 and 6 and the spherical body 4, the thickness of the core body 3 is made thin. Even so, the resin product 2 can sufficiently withstand the pressure at the time of injection molding, and the elution time of the core body 3 can be shortened. Moreover, when a metal ball is used for the spherical body 4, the core body 3 is heated by using electromagnetic induction heating to heat itself.
Since it is possible to heat the core body 3, the elution rate of the core body 3 can be further increased.

Further, since the spherical body 4 has a ball shape and moves smoothly while rolling inside the resin product 2 when the core body 3 is eluted, it can be easily taken out from the resin product 2. It does not interfere with the elution process.

The embodiment of the present invention has been described above.
The present invention is not limited to the embodiments described above, and various modifications and changes can be made based on the technical idea of the present invention.

For example, in the above-mentioned embodiment, each spherical body 4 is formed in the same shape and arranged separately,
As shown in FIG. 13, the hollow spherical bodies 4a, 4 which are connected to each other
Inserting holes 16 and 17 are provided in each of b, a connecting portion 18 extending in the radial direction is provided on the outer peripheral surface of one spherical body 4a, and the connecting portion 18 is inserted into the inserting hole 17 of the other spherical body 4b. It is also possible to arrange the two spherical bodies 4a and 4b in the core body 3 in a connected state. According to this, the plurality of spherical bodies 4a and 4b are not discharged from the inside of the resin product 2 in pieces, and the collection work is facilitated.

[0023]

As described above, in the resin core according to the present invention, a split shell is formed of a resin material that is soluble in a liquid, and a plurality of ribs are arranged on the inner wall surface of the split shell in the longitudinal direction at intervals. By providing the spherical shell between these ribs and fixing the split shell to form a hollow core body, a plurality of spherical bodies are provided inside the core body. Since the ribs and spherical bodies reinforce the core body from the inside to increase the rigidity, it is possible to reduce the thickness of the core body, which makes it possible to reduce the elution time of the core body. It can be greatly shortened and productivity can be improved. In addition, since such a core material is generally recycled and used, the amount of the core material used is small due to the thin thickness of the core body, and the recycling cost can be reduced.

Further, by using the resin core of the present invention, it is possible to sufficiently withstand the pressure during molding of the resin product even if the core body is made thin. Since there is no danger of breaking the core, the flexibility of core design is increased and various resin products with complicated shapes can be handled. Further, in the resin core of the present invention, even if a plurality of spherical bodies are arranged inside, the weight does not become so large as compared with the conventional reinforcing method of adding a filler, so the weight is reduced and the handling is easy. Become. Moreover, when the core body is eluted, each spherical body smoothly moves inside the resin product and is discharged, so that it can be easily taken out from the inside of the resin product to improve workability. Can be planned.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state before assembling a resin core according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which the resin core is assembled.

FIG. 3 is a cross-sectional view showing the vicinity of ribs in a core body that constitutes the resin core.

FIG. 4 is a cross-sectional view showing the vicinity of ribs formed in another shape inside the core body that constitutes the resin core.

FIG. 5 is a cross-sectional view showing a hollow structure spherical body disposed in the core body.

FIG. 6 is a cross-sectional view showing a halved type of the hollow structure spherical body.

FIG. 7 is a cross-sectional view showing another two-divided type of the hollow spherical body.

FIG. 8 is a front view showing a spherical body having a solid structure arranged in the core body.

FIG. 9 is a front view showing a two-divided type of the spherical body having the solid structure.

FIG. 10 is a front view showing a quarter-division type of the solid spherical body.

FIG. 11 is a cross-sectional view showing a mold for molding a resin product on the outside of the resin core.

FIG. 12 is a perspective view conceptually showing a state where the core body is eluted from the inside of the resin product.

FIG. 13 is a cross-sectional view showing a spherical body according to a modified example of the above embodiment.

FIG. 14 is a cross-sectional view showing a mold for molding a resin product on the outside of a conventional resin core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin core 2 Resin product 3 Core body 3a, 3b Split shell 4 Spherical body 5,6 Rib 9 Hot water 10 Pipe 11 Container 12 Net plate

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[Procedure amendment]

[Submission date] March 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Therefore, these split shells 3a, 3b
Is integrally formed by injection molding or the like, and a plurality of ribs 5 and 6 as shown in FIG. 3 or FIG. 4 are provided on the inner wall surface at regular intervals along the longitudinal direction. There is. These ribs 5 and 6 are provided to prevent the spherical body 4 from freely moving inside the core body 3, and the split shells 3a and 3b are fixed to assemble the core body 3. In this state, they are arranged so as to face each other.

Claims (1)

[Claims] 1. A divided shell is made of a resin material that dissolves in a liquid, a plurality of ribs are provided on an inner wall surface of the divided shell at intervals in the longitudinal direction, and a spherical body is inserted between these ribs. A resin-made core, wherein a plurality of spherical bodies are arranged inside the core body by fixing the split shells to form a hollow core body.