JP2003159722A - Synthetic-resin hollow molding and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which can increase the jointing strength of a pair of recess-like moldings and can offer a synthetic-resin hollow molding having an undercut by restraining butt parts of the recess-like moldings from being deformed to the side of a hollow part. <P>SOLUTION: This manufacturing method can offer the hollow molding 1 having the undercut 16 by undergoing: a butt process in which the respective butt parts 3a and 3b of the paired synthetic-resin moldings 2a and 2b butt against each other, so that a hollow channel 4 can be formed between the respective butt parts 3a and 3b; and a filling process in which the hollow channel 4 is filled with a molten resin in a state in which the respective moldings 2a and 2b are held in a sandwiched manner from a butt direction by molds 11 and 12 having slide cores 111, 112, 121 and 122 movable in a direction approximately orthogonal to the butt direction. In the filling process, rough surfaces 13 of the respective slide cores 111, 112, 121 and 122 having prescribed surface roughness are brought into pressure contact with outer surface sides 7 of the butt parts 3a and 3b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a synthetic resin hollow molded article and a synthetic resin hollow molded article, and more specifically, it is possible to further improve the bonding strength of a pair of concave molded articles. The present invention relates to a synthetic resin hollow molded article manufacturing method and a synthetic resin hollow molded article capable of suppressing deformation of an abutting portion of the concave molded article toward the hollow portion side.

[0002]

2. Description of the Related Art Hollow molded articles made of synthetic resin (hereinafter referred to as
It is also abbreviated as a hollow molded body. ), There is a complex shape having a predetermined thickness and a non-rotationally symmetric shape such as an intake manifold of an automobile engine. As a method for manufacturing such a hollow molded body, an abutting step of abutting the abutting portions of a pair of concave molded articles made of synthetic resin to form a hollow flow path between the abutting portions, A step of filling the hollow channel with a molten resin in a state where the pair of concave shaped bodies are sandwiched by a molding die from the abutting direction, and the pair of concave shaped bodies are integrated by solidifying the filled molten resin. There is known a manufacturing method in which a hollow molded body is obtained by mechanically bonding (JP-A-10-18923, etc.).

In the above conventional method for producing a hollow molded article, when the molding pressure of the molten resin is set to a relatively large value in the filling step, the molten resin is more smoothly filled and flowed, and the molten resin is solidified. The occurrence of voids inside the joining resin formed as described above can be suppressed, and the joining strength of the pair of concave molded bodies can be improved. However, if the molding pressure of the molten resin is set to a large pressure exceeding a predetermined value, as shown by the phantom line in FIG. 5, of the internal pressure applied perpendicularly to the inner peripheral surface of the hollow flow passage 104, the hollow portion 106 side. The inner abutment portion 131a supported in a cantilever state by the pressure component toward
131b is largely deformed toward the hollow portion 106 side, and as a result, not only the joint strength of the pair of concave shaped bodies 102a and 102b is lowered, but also the wall surface shape of the hollow portion 106 is deteriorated. . Therefore, in the conventional hollow molded body manufacturing method, the abutting portions 103a, 103
On the outer surface side 107 of b, a protruding rib 13 protruding in the abutting direction
0 is formed, and in the filling step, the protruding ribs 130 and the backup portions 140 formed on the pair of molding dies 131 and 132 are engaged with each other, whereby the hollow channel 10 is formed.
Inner abutting portions 131a, 131b due to internal pressure applied to the inside
The deformation of the hollow molded body 106 toward the hollow portion 106 side is suppressed, and the joint strength of the pair of concave shaped bodies 102a and 102b is improved.

[0004]

When an undercut portion (see reference numeral 16 in FIG. 1) in a direction substantially orthogonal to the abutting direction is set at a position close to the abutting portion as the hollow molded body, filling is performed. In the step, a slide core movable in a direction substantially orthogonal to the abutting direction is provided on the molding die, and the undercut portion is supported by the slide core. However, by using such a slide core, it is not possible to provide the protruding rib projecting in the abutting direction from the outer surface side of each abutting portion, and therefore, the deformation of the inner abutting portion toward the hollow portion side is suppressed. It was not possible to improve the bonding strength of the pair of concave molded bodies. The present invention solves the above problems, and can further improve the bonding strength of a pair of concave molded bodies, and suppress the deformation of the abutting portion of the concave molded bodies toward the hollow portion. An object of the present invention is to provide a method for producing a hollow molded body made of synthetic resin and a synthetic resin molded body which can be manufactured.

[0005]

According to the method of manufacturing a hollow molded body made of synthetic resin of the present invention, the abutting portions of a pair of concave molded bodies made of a synthetic resin are abutted to each other, and the space between the abutting portions is abutted. In the abutting step of forming a hollow channel in the, and a mold having a slide core movable in a direction substantially orthogonal to the abutting direction, while sandwiching the pair of concave shaped bodies from the abutting direction, A method of manufacturing a synthetic resin hollow molded article, comprising a filling step of filling a molten resin in a hollow channel, wherein in the filling step, a rough surface having a predetermined surface roughness provided on the slide core, The outer surface side, which is a plane substantially orthogonal to the abutting direction provided in the abutting portion, is brought into pressure contact with each other. In addition, as the above-mentioned "concave molded body", a U-shaped molded body having abutting portions projecting in a brim shape at both end edges, a U-shaped molded article having abutting portions projecting in a brim shape at both end edge sides, and the like. Can be mentioned. The "predetermined surface roughness" is preferably a ten-point average roughness (Rz) of 50 to 100.
μm.

The synthetic resin hollow-molded article of the present invention is a synthetic resin hollow-molded article manufactured by the above-mentioned manufacturing method, and has an undercut portion formed at a position close to the abutting portion. And The above "undercut part"
The term "convex and concave portions" of the molded product which hinders the removal of the molded product from the mold.

[0007]

EFFECTS OF THE INVENTION According to the method for manufacturing a synthetic resin hollow molded article of the present invention, in the filling step, a rough surface having a predetermined surface roughness provided on the slide core and an abutting direction provided on the abutting portion are provided. The outer surface side which is substantially orthogonal to each other is pressed against each other, and the frictional resistance between the rough surface of the slide core and the outer surface side of the abutting portion firmly holds the entire abutting portion, and the molding pressure of the molten resin is set to a relatively large pressure. The deformation of the inner abutting portion toward the hollow portion is suppressed. As a result, the joint strength of the pair of concave shaped bodies is further improved, deformation of the inner abutting portion toward the hollow portion side is suppressed, and the synthetic resin hollow molding having an undercut portion near the abutting portion is provided. The body can be manufactured.

According to the synthetic resin hollow molded article of the present invention,
It is possible to provide an undercut portion in the vicinity of the abutting portion in which the pair of concave shaped bodies have high bonding strength and the deformation of the inner abutting portion toward the hollow portion is suppressed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to FIGS. In this embodiment, the synthetic resin hollow molded body 1 according to the present invention is exemplified by an intake manifold held in an engine of an automobile or the like (see FIG. 4).

(1) Molding Mold First, a molding mold used in a filling step described later will be described. As shown in FIGS. 1 and 2, the molding die 10 is composed of a pair of upper and lower molding dies 11 and 12. The upper molding die 11 has a pair of slide cores 111 and 112 which are slidable in a direction substantially orthogonal to an abutting direction of a pair of concave molded bodies (arrow direction indicated by symbol P in the drawing) described later. . Further, the lower molding die 12 has a pair of slide cores 121 and 122 which are slidable in a direction substantially orthogonal to the abutting direction, similarly to the upper molding die 11 described above. These slide cores 111, 112, 121, 122
Has a rough surface 13 formed by forming fine irregularities on the entire surface thereof so as to have a predetermined surface roughness (surface roughness) (see FIGS. 2 and 3). This surface roughness is a ten-point average roughness (R
z) is about 100 μm. The lower molding die 12 is a slide core 1 that is slidable in a direction substantially orthogonal to the abutting direction at a position corresponding to a cylindrical portion of a concave molding body described later.
Has 23. The slide core 121 can be slid slightly in the abutting direction after sliding the slide core 123 in a direction substantially orthogonal to the abutting direction.

(2) Manufacture of Hollow Molded Body Made of Synthetic Resin As shown in FIGS. 1 and 2, the method for manufacturing a hollow molded body according to the present invention comprises abutting each pair of two split concave molded bodies 2a, 2b. By abutting the portions 3a and 3b, the pair of concave molded bodies 2a,
A hollow portion 6 is formed between 2b, and each abutting portion 3a, 3
an abutting step of forming a hollow channel 4 having a substantially rectangular cross section between b, and a pair of concave shaped bodies 2a by the molding die 10.
2b is sandwiched from the abutting direction, and a filling step of filling the hollow channel 4 with the molten resin is provided. Then, the pair of concave molded bodies 2a and 2b are bonded by the bonding resin 5 formed by solidifying the molten resin in the filling step, and the hollow molded body 1 is obtained.

In the abutting step, the inner abutting portion 3 that abuts at a portion near the hollow portion 6 which constitutes each abutting portion 3a, 3b.
1a and 31b, outer abutting portions 32a and 32b that abut on a portion away from the hollow portion 6, and these inner abutting portions 3
The hollow flow path 4 is formed as a closed space by opening only both ends in the flow path direction by the connection parts 33a, 33b connecting the 1a, 31b and the outer abutment parts 32a, 32b. Further, the concave portion 8 of the inner abutting portion 31a and the convex portion 9 of the inner abutting portion 31b are fitted together. Further, in the filling step, the cylindrical portion 16 (exemplified as a backup portion) formed in the concave shaped body 2b by the slide core 123 in a direction substantially orthogonal to the abutting direction is supported. In addition, each of the slide cores 111, 112, 12
Each rough surface 13 of 1 and 122 is in pressure contact with the outer surface side 7 which is a plane substantially orthogonal to the abutting direction of the abutting portions 3a and 3b.

(3) Effects of the Embodiments As described above, in the method for manufacturing the hollow molded body of the above embodiment,
In the filling step, the slide core 123 supports the cylindrical portion 16 of the recessed molded body 2b, and the rough surface 13 of each slide core 111, 112, 121, 122 allows the outer surface side 7 of each abutting portion 3a, 3b. Since they are pressed against each other, the entire abutting portions 3a and 3b can be firmly held by the frictional resistance between the rough surface 13 and the outer surface side 7 of the rough surface 13 and the molding pressure of the molten resin can be relatively reduced. Even if a large pressure is applied, the deformation of the inner abutting portions 31a and 31b toward the hollow portion 6 side is suppressed. Therefore, the pair of concave shaped bodies 2a, 2
The joint strength of b is further improved, and the inner abutting portion 31
The hollow molded body 1 having the backup portion can be manufactured by suppressing the deformation of a and 31b toward the hollow portion 6 side.

In the abutting process, the inner abutting portion 31
Since the concave portion 8 of a and the convex portion 9 of the inner abutting portion 31b are fitted to each other, each inner abutting portion 31a, 31 in the filling step.
The deformation of b toward the hollow portion 6 is further suppressed. Further, the hollow flow path 4 formed in the abutting step is formed as a closed space in which only both ends in the flow path direction are open, and is formed in a space shape having a relatively simple rectangular cross section. Therefore, in the filling step, the molten resin does not come into direct contact with the molding die 10 and is not rapidly cooled locally, but is more smoothly filled and flowed in the hollow flow path 4 and solidified. As a result, the bonding strength between the pair of concave shaped bodies 2a and 2b can be further improved.

The present invention is not limited to the above-mentioned embodiment, but various modifications may be made within the scope of the present invention according to the purpose and application. That is, in this embodiment, a plurality (four) of slide cores 111, 112, 121, 12 are used.
Although the rough surface 13 having a predetermined surface roughness is formed on all of the two, the present invention is not limited to this, and for example, the slide cores 111 and 112 (or the slide cores 121 and 122) provided on one of the molding dies. The rough surface 13 may be formed only on (). Further, the rough surface 13 is formed on each slide core 11
1, 112, 121, 122, each abutting part 3a, 3
It can be set to the entire surface area corresponding to the outer surface side 7 of b, or can be set to the local surface area partially corresponding to the outer surface side 7 of each abutting portion 3a, 3b.

Further, in the above embodiment, the cylindrical portion 16 is exemplified as the undercut portion, but the present invention is not limited to this, and a simple pin portion, hole portion or the like may be used as the undercut portion. The set number can be changed as appropriate. Further, in the above embodiment, the undercut portion in the direction substantially orthogonal to the abutting direction is illustrated, but the present invention is not limited to this, and an undercut portion inclined at a predetermined angle in the abutting direction may be used. In addition, in the filling step in the above-described embodiment, compressed air may be introduced into the hollow portion 6 to increase the internal pressure of the hollow portion 6. Thereby, it is possible to further suppress the deformation of the inner abutting portions 31a and 31b toward the hollow portion 6 side. Further, in the above-mentioned embodiment, the hollow channel 4 having a substantially rectangular cross section is illustrated, but the present invention is not limited to this, and for example, a substantially D-shaped hollow channel may be used. Substantially rectangular cross-section Further, in the above-mentioned embodiment, the synthetic resin hollow molded body according to the present invention was applied to a molded body (intake manifold) composed of a linear portion and a curved portion. Not limited to
The present invention can be applied to a molded product having only a linear portion (for example, an oil trainer) or a molded product having only a curved portion.

Although various injection molding methods can be adopted as the method for manufacturing the hollow molded article, a die slide for sliding the movable die in a straight line from the viewpoint that the above steps can be efficiently carried out. -It is preferable to adopt an injection method or an injection molding method called a die rotary injection method in which a movable die is rotated in a plane. Further, as the concave molded body and the molten resin,
For example, thermoplastic engineering resins such as polyamide and polybutylene terephthalate reinforced with reinforcing fibers such as glass fibers and carbon fibers can be mentioned. Further, the concave molded body and the molten resin may be different types of resins, but are preferably the same type of resin.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die and a synthetic resin hollow body used in a filling step.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a perspective view illustrating a slide core.

FIG. 4 is a perspective view showing an intake manifold.

FIG. 5 is an explanatory view for explaining a conventional method for manufacturing a hollow molded body.

[Explanation of symbols]

1: Synthetic resin hollow molded body, 2a, 2b: Recessed molded body,
3a, 3b: abutting part, 4: hollow channel, 7: outer surface side, 1
0: Mold, 111, 112, 121, 122: Slide core, 13: Rough surface, 16: Cylindrical part, P: Abutting direction.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F202 AD05 AD14 AG09 AG12 AG29                       AH16 CA11 CB01 CB12 CB20                       CK11 CK54 CQ01                 4F206 AD05 AD14 AG09 AG12 AG29                       AH16 JA07 JB12 JB14 JB15                       JB20 JL02 JM04 JN11 JQ81                 4F211 AD21 AD24 AG07 AG29 AH16                       TA08 TC14 TD07 TH17 TN82                       TN87

Claims (2)

[Claims] 1. An abutting step of abutting the abutting portions of a pair of concave moldings made of synthetic resin to form a hollow flow path between the abutting portions, and the abutting direction is substantially the same. A synthetic resin including a filling step of filling molten resin into the hollow channel in a state where the pair of concave molded bodies are sandwiched from the abutting direction by a molding die having a slide core movable in a direction orthogonal to each other. A method for manufacturing a hollow molded article, comprising: a rough surface having a predetermined surface roughness provided on the slide core in the filling step, and a plane substantially orthogonal to an abutting direction provided on the abutting portion. A method for producing a hollow molded body made of synthetic resin, which comprises press-contacting an outer surface side. 2. A synthetic resin hollow molded article manufactured by the manufacturing method according to claim 1, wherein an undercut portion is formed at a position close to the abutting portion. Hollow molded body.