JPH0470315A - Joint structure of multi-colored molding - Google Patents

Abstract

PURPOSE:To avoid disadvantages caused by a core and thus improve the joint strength between side wall parts by providing a protrusion projected toward a second rib on the surface of a first rib that is melt-adhered opposite to the second rib, and making a second molding melt-adhere to a part of the side peripheral surface of the protrusion. CONSTITUTION:Molten resin is filled into the whole of a first cavity 30, one side half of a third cavity 32, and the whole of the lower side and one side half of the upper side of a fourth cavity 33 in order to form a first molding 1. A protrusion 14 projected from the first rib of the first molding 1 to the side joined with a second molding 2 is formed at the lower side part of the cavity 33 and has a first joint surface 14a formed by a slide core 34 and a second joint surface 14b formed by a core 4. Following this, in a state wherein the first molding 1 is left in a movable mold 3, molten resin is filled in a second cavity 31, the remained half of the third cavity 32, and the remained half of the fourth cavity 33, thereby obtaining a second molding 2 that is melt-adhered with the first molding 1. At the second molding 2, the second side wall part 21 is allowed to melt-adhere to the end surface of the first side wall part 11 and the first joint surface 14a of the protrusion 14, and also the second rib 23 is allowed to melt-adhere to the first rib 13, and the second joint surface 14b of the protrusion 14.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a joining structure of multi-colored molded bodies molded from two or more types of resins having different materials or colors, and more specifically to joining of thin plate-like side walls. Regarding structure.

[Prior Art] Decorative members used in and around tail lamps of automobiles are often designed in two colors due to the color scheme of stop lamps and blinker lamps. Conventionally, such decorative members have been formed by separately forming molded bodies of each color and then mounting them in combination. However, the special public service 1986-440
As seen in Publication No. 46, a two-color molding method has been established in recent years, and it has advantages such as high productivity and excellent appearance, so it is recommended to apply this two-color molding method to the above-mentioned decorative members. It is being considered.

In this two-color molding method, first, a first resin material is injected into a cavity formed by a movable mold and a first fixed mold to form a first molded body, and then the first molded body is left on the surface of the movable mold. In this state, a second molded body is formed from the second resin material together with the second fixed mold. As a result, the first molded body and the second molded body are fused at their respective contact portions, and an integrally joined two-color molded body is obtained.

[Problems to be Solved by the Invention] Some of the above-described decorative members for automobiles have a shape as shown in FIG. 7 on the back side. This decorative member is the first
It is composed of a molded body 100 and a second molded body 200. The first molded body 100 includes a first plane portion 1 constituting a design portion.
01, a thin plate-shaped first side wall portion 102 protruding toward the back side of the first flat portion 101, and a reinforcing rib 103 extending along the edge of the first flat portion 101. In addition, the second molded body 200
A second plane part 201 constituting a design part, a thin plate-shaped second side wall part 202 protruding from the back side of the second plane part 201, and a reinforcing rib 20 extending along an end of the second plane part 201.
It has 3. When such a decorative member is formed by a two-color molding method, the end faces of the first side wall portion 102 and the second side wall portion 202 are fused together, and the reinforcing ribs 103 and 203 are fused together.

However, since the first side wall part 102 and the second side wall part 202 are joined to each other in a butted structure, there is a problem that sufficient joint strength cannot be obtained when each plate is thin. Therefore, as shown in FIG.
．． It is conceivable to provide a first rib 104 that is continuous with 203 and protrudes inward from the end of the first side wall 102, and a second rib 204 that protrudes inward from the second side wall 202@.

With this configuration, the first rib 104 and the second rib 20
4 are fused to each other, a sufficient bonding area can be secured even at the end surfaces of the first side wall portion 102 and the second side wall portion 202, so that bonding strength can be ensured.

In the case of a decorative member having the shape described above, the first plane part 101
The portions other than the second flat portion 201 are usually molded using a cavity formed in a movable mold. When forming the first molded body 100, a slide core provided in the movable mold is used to prevent the resin from flowing from the cavity forming the first side wall part 102 to the cavity forming the second side wall part 202. It is necessary to close the cavity forming the second side wall portion 202. In addition, the reinforcing rib 103 and the first
The reinforcing ribs 203 and the second ribs 204 are formed by plate-shaped inserts provided on the fixed mold so that the resin does not flow from the cavities forming the ribs 104 to the cavities forming the reinforcing ribs 203 and the second ribs 204. It is necessary to close the cavity.

However, as shown in FIG.
When forming a first molded body having a shape in which the rib 204 protrudes from the entire end portions of the first side wall portion 102 and the second side wall portion 202, the portion that closes the cavity forming the tip portion of the second rib 204 is Since the shape of the insert becomes thinner, the number of man-hours required to manufacture the insert increases, and there is a risk that problems such as damage to the mold and breakage may occur during use. Furthermore, from a design point of view, it is often desirable for the volumes of the first rib 104 and the second rib 204 to be smaller, and in this case, not only will the insert become thinner, but a sufficient welding area may not be obtained. It also happens.

The present invention was made in view of these circumstances, and
The purpose is to avoid problems caused by nesting and to improve the bonding strength between side wall portions.

[Means for Solving the Problems] The joining structure of the multicolored molded body of the present invention includes a first plane part, a thin plate-shaped first side wall part protruding to the back side of the first plane part, and an end of the first side wall part. a first molded body having a first rib protruding inward from a second plane part, a thin plate-like second side wall part protruding to the back side of the second plane part, and an inner side from an end of the second side wall part; a second molded body having a second rib protruding from the molded body, and at least the first rib and the second rib are fused together so that the first side wall portion and the second side wall portion are located on the same straight line. A joint structure of integrally joined multicolored molded bodies, wherein the first rib has a convex portion protruding toward the second rib on the surface fused to the second rib, and [Operations and Effects of the Invention] In the joining structure of the multicolored molded product of the present invention, the first rib is fused to the second rib. The opposing fused surfaces have a convex portion projecting toward the second rib, and the second molded body is fused to a part of the side peripheral surface of the convex portion. Here, since the convex portion protrudes from the surface of the first rib, the side circumferential surface of the convex portion has a shape substantially perpendicular to the surface of the first rib. That is, the second molded body has at least two planes that are substantially orthogonal to each other at the end of the second side wall portion.
Since it is fused to the molded body, high bonding strength can be obtained even if the bonding area is small. Further, by adjusting the shape of the convex portion, it is possible to configure the convex portion to be fused in three mutually orthogonal planes, and in this case, particularly high bonding strength can be obtained.

Further, a convex portion can be formed on the first rear using a part of the cavity forming the second rib.

In other words, when forming the first rib, a part of the cavity forming the second rib is not blocked with a nest, and the resin forming the first molded body is configured to flow into that part, so that the first rib is formed. A convex portion can be formed. Therefore, it is not necessary to make the shape of the insert thinner, and problems such as increased man-hours for manufacturing the insert and damage to the mold can be avoided.

[Examples] Hereinafter, examples will be specifically described with reference to the drawings.

FIG. 1 shows a perspective view of the main parts of the two-color molded product of this example as seen from the back side, and FIG. 6 shows an enlarged perspective view of the main parts. This two-color molded body is a decorative member for an automobile composed of a first molded body 1 and a second molded body 2. The first molded body 1 includes a first plane part 10 constituting a design part, a thin plate-shaped first side wall part 11 protruding toward the back side of the first plane part 10, and a first plane part 1.
The reinforcing rib 12 protrudes inwardly along the edge of the first side wall 11, and the first rib 13 protrudes inwardly from the edge of the first side wall 11, and is made of red transparent resin.

The second molded body 2 includes a second flat part 20, a thin plate-shaped second side wall part 21 that protrudes toward the back side of the second flat part 20, and a reinforcement that protrudes inward along the end of the second flat part 20. It is composed of a rib 22 and a second rib 23 that protrudes inward from the end of the second side wall 21, and is made of yellow transparent resin.

Hereinafter, the detailed structure will be explained while explaining the method of manufacturing this two-color molded body.

The main parts of the movable mold 3 used in FIG. 2 are shown. For movable type 3,
A first cavity 30 forming the first side wall portion 11 and a second cavity 30 forming the first side wall portion 11.
A second cavity 31 forming the side wall portion 21 and a third cavity 32 forming the reinforcing rib 12 and the reinforcing rib 22.
and a fourth cavity 33 in which the first rib 13 and the second rib 23 are formed inside the third cavity 32.
is formed. In addition, the movable mold 3 has a second cavity 3
It has a slide core 34 that can freely move in and out. Further, the plate-shaped insert 4 is configured to close a portion of the third cavity 32 where the reinforcing rib 22 is formed and a portion of the fourth cavity 33 where the second rib 23 is formed.

(1) Formation of the first molded body 1 As shown in FIG. 2, the slide core 34 is advanced to close the communication between the second cavity 31 and the first cavity 30. Further, the insert 4 is placed in contact with the slide core 34, and closes a portion of the third cavity 32 where the reinforcing rib 22 is formed and a portion of the fourth cavity 33 where the second rib 23 is formed. Then, the mold is clamped with a fixed mold (not shown).
A first molded body is formed by injection molding using a red transparent acrylic resin. The molten resin is applied to the body of the first cavity 30, one half of the third cavity 32, and the fourth cavity 33.
Fill the entire lower side and half of one side of the upper side shown in Figure 2 of
A molded body 1 is formed.

Here, the insert 4 has a rectangular shape in plan view, and has the same shape as that used when forming the reinforcing rib 103 shown in FIG. 7. That is, since there is no thin part protruding into the interior of the fourth cavity 33, there is no increase in the number of man-hours for manufacturing the insert 4, and problems such as damage to the mold during use are avoided.

3 and 4 are perspective views of essential parts of the obtained first molded body 1.
As shown in the figure. The first molded body 1 includes a first plane part 10 constituting a design part, a thin plate-shaped first side wall part 11 protruding toward the back side of the first plane part 10, and a first side wall part 11 along the edge of the first plane part 10. A reinforcing rib 12 that protrudes inward, a first rib 13 that is continuous with the reinforcing rib 12 and protrudes inward from the end of the first side wall 11, and a side from the first rib 13 to which the second molded body 2 is joined. It is composed of a protruding convex portion 14.

The convex portion 14 is formed at the lower part of the fourth cavity 33,
A first bonding surface 14a formed by the slide core 34 and perpendicular to the surface of the first rib 13, and a first joint surface 14a formed by the insert 4.
The second joint surface 14b is perpendicular to the surface of the rib] 3 and the first joint surface 14a, respectively.

(2) Formation of the second molded body 2 Next, with the first molded body 1 left in the movable mold 3, the slide core 34 is moved back as shown in FIG. 5, and the insert 4 is removed. 2 Clamp with the fixed mold for molded body 2. Then, the second molded body 2 is formed by injection molding using a yellow transparent acrylic resin.

The remaining half of the second cavity 31, the third cavity 32, and the remaining half of the fourth cavity 33 are filled with the molten resin, and a second molded body 2 fused to the first molded body 1 is obtained.

In the second molded body 2, as shown in FIG.
is the end surface of the first side wall portion 11 and the first joint surface 1 of the convex portion 14
4a, and the second rib 23 is fused to the first rib 13 and the second joint surface 14b of the convex portion 14. That is, the second side wall portion 21 is fused and joined to three mutually orthogonal planes (the surface of the first rib 13, the first joint surface 14a, and the second joint surface 14b) at its end, so that the joint Although the area is small, high bonding strength is ensured, and cracking at the bonded portion is reliably prevented in the event of an impact.

[Brief explanation of the drawing]

Figures 1 to 6 relate to the joining structure of a two-color molded body according to an embodiment of the present invention. 3 and 4 are perspective views of the main parts of the first molded body, respectively. FIG. 5 is a perspective view of the main parts of the movable mold during molding of the second molded body, and FIG. 6 is a perspective view of the main parts of the movable mold. FIG. 2 is an enlarged perspective view of a main part of a two-color molded body. Figure 7 shows the conventional 2
It is a perspective view of the main part of a color molded object. FIG. 8 is a perspective view of essential parts of a hypothetical two-color molded product devised in the process of transitioning from the conventional molded product shown in FIG. 7 to the present invention. 1... First molded body 2... Second molded body 3...
- Movable type 4... Insert 10... First plane part 20... Second plane part 11... First side wall part
21...Second side wall portion 12...Reinforcement rib
22... Reinforcement rib 13... First rib 23-
...Second rib 14...Protrusion Fig. 1 Patent applicant Toyoda Gosei Co., Ltd. agent Patent attorney Hiroshi Okawa Fig. 3 Prefecture 4

Claims (1)

[Claims] (1) A first molded body having a first plane part, a thin plate-shaped first side wall part protruding to the back side of the first plane part, and a first rib protruding inward from the end of the first side wall part. and a second molded body having a second plane part, a thin plate-like second side wall part protruding from the back side of the second plane part, and a second rib protruding inward from an end of the second side wall part. At least the first rib and the second rib are fused and integrally joined so that the first side wall portion and the second side wall portion are located on the same straight line. In the joining structure, the first rib has a convex portion protruding toward the second rib on a surface fused to the second rib, and
A joining structure for multicolored molded bodies, characterized in that the molded body is also fused to a part of the side peripheral surface of the convex portion.