JPH06179246A - Joint structure of hollow synthetic resin - Google Patents

Abstract

(57) [Abstract] [Purpose] In the case of manufacturing a hollow body by abutting half-split bodies, the present invention provides a joining structure that gives a large joining strength without providing a slide structure in a mold. To do. The present invention has a structure in which injection-molded halves are abutted with each other in their respective molds, and a molten resin material for joining is injected into the abutting portions to join the halves. The joint end surface of is a concave-convex surface that protrudes in the direction orthogonal to this along the longitudinal direction, and is formed so that the molten resin is injected into a curved path or a multi-way path formed by the concave-convex surface in an abutting state. And a joint structure of synthetic resin hollow bodies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure of a joining portion in the case where a hollow body is manufactured by abutting and joining an injection-molded half body.

[0002]

Blow molding is generally used as a method for manufacturing a hollow container. However, in consideration of the structural strength or shape of the hollow body, the divided half body is subjected to primary injection molding, and the half body is then injected. A two-step molding method has been proposed in which a resin is abutted against each other and a resin is secondarily injection-molded at the abutting portion (Patent Publication 2).
-20410). However, when the entire hollow body is large and the joints need to have a certain level of joint strength, there is a problem in that it is not sufficient to injection-mold a molten resin for joining the joints.

[0003]

By the way, in the case of manufacturing a hollow body by abutting half-split bodies, in order to give a certain joint strength to the joint portion of the hollow body, the joint surface is perpendicular to the horizontal direction. It is desirable that both joint surfaces engage with each other in different directions, but in order to perform engagement in the vertical direction, a slide structure is attached to the mold to form an engaging portion orthogonal to the mold cutting direction. However, it is necessary to have a structure for retracting the slide core when the die is removed, which causes a problem of complicating the die structure. Therefore, an object of the present invention is to provide a joining structure that provides a joining force with a large joining strength without providing such a slide structure in a mold.

[0004]

According to the present invention, when a concavo-convex surface is formed in the joining surface in the longitudinal direction and a curved path is formed in the longitudinal direction in the abutting state of the hollow body by the concavo-convex surface, the die cutting direction, that is, This was done by paying attention to the fact that the engaging force in the direction perpendicular to the joining surface can be increased. The injection-molded halves are joined to the abutting portion by abutting their end faces against each other in the mold. In the structure of injecting a molten resin material for joining and joining, the joining end surface of each half is an uneven surface projecting in the direction orthogonal to this in the longitudinal direction, and in the abutting state, the uneven surface extends in the longitudinal direction. It is a joint structure of synthetic resin hollow bodies, which is characterized in that it is formed so that the molten resin is injected into the curved path to be formed. In the present invention, the concavo-convex surface may be one that goes in and out in the die-cutting direction or one that goes in and out in the joint surface width direction, and the curved path means a void path that is not straight, and is laterally intermittent from the central void. Includes branch roads that have branches.

[0005]

According to the present invention, since the joint end face only forms the uneven surface in the die cutting direction which is orthogonal to the joint end face in the longitudinal direction, it can be formed without attaching the slide structure to the die. Moreover, since the uneven surface forms a curved path in an abutting state, the molten resin injected into the curved path has a large contact area with the joint end surface, and can have a strong joint strength.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing a molding state of the joint structure of the present invention, showing a state before mold clamping for secondary molding after primary molding of each half body of the hollow body.
2 is an enlarged perspective view of an essential part thereof, FIG. 3 is a sectional view showing a state where molten resin is injected into the joint structure of the present invention after mold clamping for secondary molding, and FIG. 4 is an enlarged perspective view of the essential part. Is.

In the drawings, 1 is an upper mold, 2 is a lower mold, and hollow halves 3 and 4 are formed in each. The half-split body 3 has outwardly projecting flange portions 31 and 32 on the peripheral portion of the main body portion 30, and a zigzag-shaped uneven portion 33 projecting in the die-cutting direction along the longitudinal direction on the joint end surface thereof.
Are formed. On the other hand, the half-divided body 4 also has a flange portion 4 that protrudes outward at a slightly lowered position on the peripheral portion of the main body portion 40.
1 and 42, and a zigzag-shaped concavo-convex portion 43 protruding upward that meshes with the concavo-convex portion 33 is formed on the joint end surface in the longitudinal direction.

The concavo-convex portions 33 and 43 are preferably formed so as to extend over the entire length of the peripheral portion of the half-split body (see FIG. 2). The concave and convex portions 33 and 43 formed on the joint end face form a curved cross-section R1 as shown in FIG. 3 in the abutting state of the half-split bodies 3 and 4, so that the curved path R1 is formed via a spool.
When the molten resin B is injected into the joint end face, the joint force of the molten resin acts on the joint end faces of the halves 3 and 4 over the joint area enlarged by the curved path.

As shown in FIG. 5, the cross-section bending path R1 is directly connected to the end face as shown in FIG. 6 when the end face is thick like the half-divided bodies 5 and 6 of the circular cross-section hollow body. Zigzag-shaped concave and convex portions 52 and 62 may be formed. In this case, a part of the joint end surfaces 51 and 61 is brought into direct contact with each other to form the cross-sectional bending path R2 which the concave and convex portions 52 and 62 face each other so as to mesh with each other and which moves in and out in the die cutting direction. Is good. Also, as shown in FIG.
The innermost first convex portions 53, 63 of the joint end surfaces are brought into contact with each other, while the outermost second convex portions 54, 64 are opposed to each other with a constant interval, and the first convex portions 53, 63 and A curved path R2 (FIG. 8) in which the concave portions 55 and 65 between the two convex portions 54 and 64 are bent in the horizontal direction (bonding surface width direction) and extend in the longitudinal direction.
(See FIG. 9) or R3 (see FIG. 9) may be formed so as to increase the area of the joint portion in contact with the molten resin.

[0010]

As is apparent from the above description, according to the present invention, a molten resin for joining injection-molded halves to their abutting portions by abutting their end faces against each other in a mold. In the structure in which the material is injected and bonded, the joint end surface of each half body is only formed with the uneven surface that goes in and out in the direction orthogonal to the longitudinal direction, so it can be molded without attaching the slide structure. is there. In addition, since the uneven surface forms a curved path (or a multi-way path) in the abutting state, the contact area of the joint end surface is enlarged, and molten resin is injected into the joint area for joining, so that a strong joint strength is obtained. Can have

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molded state of a joint structure of the present invention,

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

FIG. 3 is a cross-sectional view showing a state where molten resin is injected into the joint structure of the present invention,

FIG. 4 is an enlarged perspective view of an essential part of FIG.

FIG. 5 is a cross-sectional view when the first modification of the joining structure of the present invention is applied to another hollow body,

6 is an enlarged side view of the main part of FIG.

FIG. 7 is a cross-sectional view of second and third modified examples of the joining structure of the present invention,

FIG. 8 is a sectional view of the second modification in the direction of the arrow in FIG. 7,

FIG. 9 is a sectional view of the third modification in the direction of the arrow in FIG.

[Explanation of symbols]

1 is an upper mold, 2 is a lower mold, 3 and 4 are hollow halves, 3
0 and 40 are main body parts, 31, 32 are flange parts, 33
Is an uneven part, 41 is a flange part, 43 is an uneven part, R1, R
2 and R3 are bends.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Shozo Nishida Shozo Nishida 1-6-7 Funakoshi Minami, Aki-ku, Hiroshima City, Hiroshima Prefecture Japan Steel Works, Ltd.Hiroshima Works (72) Inventor Naoshi Kiyama Hachihonmatsucho, Higashihiroshima City, Hiroshima Prefecture Daikyo Hara No. 175 1 Daikyo Co., Ltd.

Claims (1)

[Claims] 1. A structure in which injection-molded halves are abutted against each other in their respective molds and a molten resin material for joining is injected into the abutting portions to join the halves. The joint end surface is an uneven surface protruding in a direction orthogonal to the longitudinal direction, and is formed so that the molten resin is injected into a curved path formed in the longitudinal direction in the abutting state. The joint structure of synthetic resin hollow bodies.