JPS6312981Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an injection mold for molding the material by injecting the material into the space between the cavity mold and the core mold, and is particularly concerned with injection molds made of materials of different colors or compositions. The present invention relates to such a mold capable of forming a product with two parts.

One known method of injection molding a two-part product of two different materials is to use two molds, each having a cavity mold and a core mold. According to the above, it is clear that the mold cost is high and the process is complicated. Alternatively, it is known to form a product with two parts of different materials in the same mold, with the parts moved by a drive device such as a hydraulic cylinder. This method requires a hydraulic mechanism and has drawbacks such as a complicated mold and inconvenience in handling.

The purpose of this invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to achieve this purpose, the cavity mold has a receiving hole that opens toward the void between the cavity mold and the core mold. A main body portion provided with a main body portion, and a movable portion housed in a housing hole so as to be entirely movable with respect to the main body portion,
A partition rim extending along the main body and projecting toward the core mold is formed around the movable part and communicates with the main body side cavity between the main body and the core mold on the outside of the partition flange. do. An injection channel for a first material, which is different from the first material, is provided between the main body portion and the core mold, and further communicates with the movable portion side cavity between the movable portion and the core mold inwardly of the partition flange. An injection channel for the second material is provided in the core mold with an opening corresponding to approximately the center of the movable part.

According to this configuration according to this invention, before the start of the injection operation, the movable part of the cavity mold that is movable as a whole is pressed toward the core mold by the action of the spring, so that the partition edge of the movable part is pressed against the core mold. It is held in contact with the core mold, so that the body part side cavity between the body part and the core mold and the movable part side cavity between the movable part and the core mold are separated by the partitioning edge. If the first material is injected into the cavity on the side of the main body in this state, this material will fill this cavity but will not enter the cavity on the side of the movable part because it will be blocked by the partition ridge. Next, when a second material is injected and press-fitted from a material injection path that has an opening provided at a position corresponding to approximately the center of the movable part of the core mold, the movable part counteracts the force of the spring due to this press-in pressure. The partitioning edge then moves away from the core mold, and thus the partitioning edge separates from the core mold.
In this way, the second material not only fills the cavity on the side of the movable part, but also fills the gap created between the partition flange and the core mold, and also comes into contact with and becomes integrated with the first material in the cavity on the body side. In this way, according to this invention, a product having the above-mentioned structure can be formed extremely easily with one mold without using a hydraulic mechanism, and therefore, the drawbacks of the conventional method are eliminated.

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 show a wheel cover 1, which is an example of a product to be manufactured by this invention. The wheel cover 1 has a disc shape with bent and curved parts, and a portion 3 outside the dashed circle 2 is made of a first material A, and a portion 4 inside the dashed circle 2 is made of the first material and color. are formed of a second material B having different properties.

The mold 5 for forming the above-mentioned wheel cover 1 is composed of a core mold 6 and a cavity mold 7, as shown in FIG. The cavity mold 7 has a body part 8 that is held in contact with the core mold 6 during the injection molding operation, and this body part 8 has a shouldered cylindrical receiving hole 9 in the center having a diameter equal to the dashed circle 2 at its inner end. Be prepared. A shouldered cylindrical cavity-type movable part 10 is movably accommodated in the accommodation hole 9, and this movable part 10 is supported by the action of a compression spring 11 arranged between the shoulder of this movable part 10 and the shoulder of the main body part 8. It is elastically pushed in the direction of protruding from the main body part 8 (that is, toward the core mold 6 in the normal state where the main body part 8 and the core mold 6 are in contact). The movable part 10 has a partition edge 12 that protrudes along its circumference.
The partitioning edge 12 is normally held in contact with the core mold 6 when the movable member 10 is elastically pressed. On the opposing surfaces of the cavity mold 7 and the core mold 6, a main body part side cavity 13 to be filled with the first material A is formed between the main body part 8 and the core mold 6 and outside the partition flange 12, and is movable. A second material B is placed between the portion 10 and the core mold 6 and inside the main body portion side cavity 13.
(The shape and size of the space 14 change as the movable part 10 moves). An injection path 15 for injecting the first material A into the main body side cavity 13 is provided between the main body portion 8 and the core mold 6,
In addition, an injection path 16 for injecting the second material B into the movable part side cavity 14 is provided in the core mold 16 . This injection path 16 has an opening at a position corresponding to approximately the center of the movable portion 10.

Next, an injection molding operation using the above-mentioned mold will be explained. First, the first material A is injected through the injection path 15 into the cavity 13 on the main body side of the mold 5 arranged as shown in FIG. This first material A is blocked by the partition ridge 12 and moves into the movable part side space 14.
Do not invade inside. Thus, as shown in FIG.
is formed. Next, when the second material B is injected and press-fitted into the movable part side cavity 14 through the injection path 16,
The movable part 10 retreats to the left by the press-fitting pressure against the action of the spring 11, and the movable part side space 14 expands to the position shown by the broken line in FIG. Stay away from 6. Thus, as shown in FIG. 5, the second material B fills the expanded moving part side cavity 14 and the gap between the partitioning flange 12 and the core mold 6 and contacts the first material A in this gap. It is integrated with this. In this way, an inner part 4 is formed which is integral with the outer part 3 of the wheel cover.

In addition, in the configuration according to this invention, only the partitioning edge 12 of the movable part 10 is made movable,
The mold with other parts fixedly arranged was
Although it can be conceived based on the idea disclosed in Publication No. 255,
The disadvantage of this mold is that only the partition edge moves, which causes unevenness in the molded product.
Furthermore, since a large injection pressure is required to move the partition edge, a powerful molding machine is required and there is a risk that burrs will form on the mating surfaces. Compared to this, in the mold according to this invention, since the movable part 10 moves as a whole, there is no risk of unevenness in the molded product, the required injection pressure can be reduced, and a powerful molding machine is therefore unnecessary. , and the possibility of burrs occurring is reduced.

Further, according to this invention, since the opening of the injection path 16 for the second material B is provided at a position corresponding to approximately the center of the movable portion 10 as shown in the figure, the material is filled in the entire cavity 14. It is distributed evenly and no lateral forces are applied to the movable part 10, so that the movable part can be reliably pressed down with low material pressure, ie, retracted to the left in the drawing.

[Brief explanation of the drawing]

Figure 1 is a front view of a wheel cover, which is an example of a product made with the mold of this invention, Figure 2 is a sectional view along the diameter of the wheel cover of Figure 1, and Figure 3 is a diagram of the wheel cover of this invention. Partial cross-section along the diameter of the mold,
Fig. 4 is a drawing similar to Fig. 3, showing a state in which the first material is injected into the mold shown in Fig. 3, and Fig. 5 is a drawing showing a state in which the second material is further injected into the mold shown in Fig. 3. This is a drawing similar to FIG. 3. In the drawings, 5 is a mold, 6 is a core mold, 7 is a cavity mold, 8 is a main body part, 10 is a movable part, 1
1 indicates a spring, and 12 indicates a partition edge.

Claims (1)

[Claims for Utility Model Registration] 1. In an injection mold for molding a material by injecting material into a space between a cavity mold 7 and a core mold 6, the cavity mold is and a body part 8 with a receiving hole 9 opening towards the cavity between the core mold and a movable part 10 accommodated in the receiving hole so as to be entirely movable relative thereto. A partitioning rim 12 extending along the main body portion and protruding toward the core mold is formed around the movable part, and the main body portion and the core mold are formed on the outside of the partitioning rim. An injection path 15 for the first material A is provided between the main body portion and the core mold, and communicates with the main body portion side cavity 13 between the movable portion and the core inside the partition flange. An injection path 16 for a second material B different from the first material, communicating with the movable part side cavity 14 between the molds.
for forming a product with two parts made of different materials, characterized in that the core mold has an opening corresponding to approximately the center of the movable part. Mold for injection molding. 2. The injection mold according to claim 1, wherein the movable part is pressed against the core mold by a spring 11.