JPH0356651B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a design surface provided with a rear design forming part,
The present invention relates to a mold for molding an insert molded product formed on an insert.

Examples of this type of insert molded product include automobile horn pads, marks, and emblems.

<Conventional technology> Conventionally, for example, horn pads of automobiles, etc.
As shown in the figure, insert 1 made of hard synthetic resin
After setting it in the movable mold 2 of the mold, close the mold,
A fixed mold 4 having a shaped surface 3 with a design surface and the movable mold 2
constitute a product cavity 5, and inject a soft synthetic resin material into the product cavity 5 by injection or the like,
After cooling and solidifying, the mold was opened and released to be molded. The rear design forming part 7 formed in the middle part of the design surface of the molded product 6 after being released from the mold is usually a recessed part, as shown in FIG. wear it. In addition, molded product 6
In order to prevent the molding material from adhering to the fixed mold side and from peeling off from the insert 1, the molding material also wraps around the back side of the insert outer peripheral portion 10.

<Problems to be Solved by the Invention> In the above-mentioned mold release, the molded product 6 is released from the movable mold 2 using the ejector pin 9 as shown in the figure. Since the amount of wraparound is small only at the outer circumferential portion 10 of the insert, there was a problem that the molded product 6 easily adhered to the fixed mold 4 side when the mold was opened, making it difficult to release the mold smoothly. If the molded product 6 attached to the fixed mold 4 side is later tried to be released by hand, the attached surface is the designed surface 6a, so the designed surface is likely to be damaged.
Molded product defects were more likely to occur.

It is conceivable to pass the material over the entire back surface of the insert 1 so that the molded product 6 remains on the movable mold 4 side, but this would result in the insert being held in the middle, making the insert holding mechanism complicated and impractical. This is undesirable as it requires a large amount of heat, which leads to an increase in the weight of the molded product.

<Means for Solving the Problems> As a result of intensive development efforts in order to solve the above-mentioned problems, the present inventors came up with a molding die having the following characteristics, and completed the present invention.

A mold for molding an insert molded product in which a designed surface including a rear design forming part is formed on the insert, comprising a movable mold for setting the insert and a fixed mold for forming the designed surface. When the mold is closed, the movable mold and the fixed mold form a product cavity, and an insert is inserted into a holding hole formed in the fixed mold so as to be slidable back and forth in the same direction as the mold opening/closing direction. A presser pin is provided inside, and the insert presser pin is provided with a biasing means in the direction of the movable mold, and has a small-diameter convex portion formed at its tip, and serves as a presser step for shaping the post-design forming part during molding. a portion of the holding hole that is continuous with the product cavity is fitted with the insert holding pin in a clearance fit that makes it difficult for molding material to flow in, and an air flow path communicating with the holding hole is formed. , is formed in the fixed mold.

<Example> An example of the present invention will be described based on illustrated examples. The same parts as those in the conventional example are given the same reference numerals and the explanation will be omitted.

As shown in FIGS. 1 and 2, an insert presser pin 11 is installed inside a holding hole 12 formed in the fixed mold 4 so as to be slidable back and forth in the same direction as the mold opening/closing direction, and the insert presser pin 11 is movable. A means for biasing the mold in two directions is provided. Specifically, a holding hole 12 for an insert presser pin 11 is formed in the shaping area of the rear design forming part of the fixed die 4 so as to be continuous with the product cavity 5. The stationary platen side is a large diameter part 15, and the product cavity side is a small diameter part 16. Furthermore, a certain distance (usually several mm) of the small diameter part 16 continuous with the product cavity 5 side is a fitting hole 16a. It is said that The insert holding pin 11 has a flange part 17 in the middle, and the fixed platen 1 of the flange part 17
A biasing coil spring 18 is attached to the third side, and the product cavity 5 side is fitted into the fitting hole 16a with a clearance fit (same as the fit of the ejector pin 9) that makes it difficult for molding material to flow in. , the tip thereof is a small diameter convex portion 19 having the same height as the thickness of the rear design forming portion 7. Naturally, the outer diameter of the flange portion 17 is smaller than the large diameter portion 15 of the holding hole 12 and larger than the small diameter portion 16. A stepped portion 20 is formed.
It is now locked in place. Furthermore, the fixed mold 4 has a holding hole 12 for the insert holding pin 11.
In other words, the air inflow path 21 communicates with the fitting hole 16a.
is formed.

Next, how the above embodiment is used will be explained.

First, with the mold open, insert 1 into movable mold 2.
Set to . At this time, the material for forming the insert is usually a hard synthetic resin such as ABS resin or polyamide, but it may also be made of metal. Next, when the mold is closed, a product cavity 5 is constituted by a fixed mold 4 having a design surface 3 and a movable mold 2 (first
figure). Here, the insert holding pin 11 is biased by a coil spring 18 and comes into contact with the insert 1 at a small diameter convex portion 19, forming a part of the shaping surface of the rear design forming section.

Subsequently, a soft synthetic resin material is injected into the product cavity 5 by injection or the like. Here, examples of the soft synthetic resin material include soft polyvinyl chloride and soft polyurethane. At this time,
The fitting hole 16a communicating with the product cavity 5 has a
Although the insert holding pin 11 is fitted with a clearance, it is difficult for the molding material to flow in, so the molding material does not flow through the gap.

After the synthetic resin material in the product cavity 5 is cooled and solidified, the mold is opened. At this time, the air inflow path 21 is connected to a compressor (not shown) or the like to apply air pressure. Then, the design surface 6a of the molded product 6 is aligned with the presser stepped portion 1 of the insert presser pin.
1a (the insert 1 is also held down by the holding pin 11)
It is held down by the protrusion 19 at the tip. ) and the air ejected from the gap between the insert presser pin 11 and the fitting hole 16a flows between the designed surface 6a of the molded product and the designed surface 3 of the fixed mold, thereby ensuring that the designed surface of the fixed mold 4 is It separates from the shaping surface 3. Subsequently, the molded product 6 is separated from the movable mold 2 by the action of the ejector pin 9, and mold release is completed.

In the above embodiment, the case where there is one rear design forming section 7 is taken as an example, but in the case where there is a plurality of rear design forming sections 7, it is desirable to provide a plurality of corresponding insert presser pins. Furthermore, the aspect of the rear design forming part does not have to be a concave part, but may be flush or a convex part. Furthermore, the height of the small diameter convex portion 19 may not be the same as the thickness of the rear design forming portion 7, but may be slightly lower.

<Actions and Effects of the Invention> As described above, in the molding die of the present invention, when the mold is opened, the designed surface is pressed by the insert presser pin, and moreover, the molding die is pressed against the fixed designed surface and the molded surface. Since air is blown between the product and the design surface, the molded product does not stick to the fixed mold, and the mold can be released smoothly without damaging the design surface.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the molding die of the present invention, and Figure 1 is a partial sectional view before injection of mold closing material;
Fig. 2 is a partial sectional view immediately after the mold opens, Fig. 3 is a schematic sectional view showing an example of a conventional molding die, and Fig. 4 is a molded product having a design surface with a rear design forming part. It is an exploded perspective view showing an example. 1... insert, 2... movable type, 4... fixed type, 5... product cavity, 6... molded product, 6a
. . . Design surface, 7 .

Claims (1)

[Scope of Claims] 1. A mold for molding an insert molded product in which a designed surface including a rear design forming part is formed on an insert, comprising a movable mold for setting the insert, and a movable mold for setting the designed surface. The movable mold and the fixed mold form a product cavity when the mold is closed. An insert holding pin is installed inside the insert holding pin so as to be slidable back and forth in the direction of the movable mold. A presser stepped portion is formed to shape the forming part, and the fitting hole formed in the continuous portion of the holding hole with the product cavity is fitted with the insert presser pin through a clearance fit that makes it difficult for the molding material to flow in. A molding die characterized in that an air flow path communicating with the holding hole is formed in the fixed mold.