JP2837335B2 - Mold structure for thin wall molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a mold for injection molding, and more particularly to the structure of a thin mold for injection molding, which can prevent defects occurring when releasing a thin molded product after injection molding. It relates to the structure of the mold.

[0002]

2. Description of the Related Art In general, a molding process for producing a molded product by injection molding includes a mold clamping for closing a mold for injecting a resin, a resin injection, a pressure-holding / cooling, and a release of a molded product from a mold. This is performed in four steps. FIG. 3 is a view showing each step of the injection molding using a conventional mold. In FIG.
Is a movable mold, 12 is a fixed mold, 13 is a cylinder, 1
4 is a screw, 15 is a resin, 16 is a molded product, and 17 is an ejector pin for releasing the molded product from the mold 11.

In the case of performing injection molding, as shown in FIG. 1A, the movable mold 11 and the fixed mold 12 are combined and clamped, and as shown in FIG. Then, the screw 14 of the cylinder 13 is advanced to inject the resin 15 into the mold. Next, as shown in (c), after holding pressure and cooling, as shown in (d), the movable mold 11 is moved.
From the fixed mold. Then, as shown in (e), the molded product 16 attached to the movable mold 11 is released by the ejector pin 17.

[0004]

However, in recent years, as the size and weight of products are reduced, the thickness of molded products tends to be reduced. For this reason, after the steps (a) to (d) of FIG. 3, the molded product is ejected by the ejector pins 17 in the step (e).
When the ejector pin 17 hits the thin portion of the molded product 16 when the mold is pressed and released, the molded product may be deformed or broken due to excessive force applied thereto.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and uses a spring resilience to absorb the force of an ejector pin. An object of the present invention is to provide a thin-wall molding die that can prevent breakage and the like and reduce the occurrence of defective molded products.

[0006]

According to a first aspect of the present invention, a movable mold 1 and a fixed mold 2 are provided, and the movable mold 1 and the fixed mold are provided. After injecting the resin into the space formed by the mold 2, the movable mold 1 is moved together with the molded product to separate the fixed mold 2 and the movable mold 1, and penetrate the movable mold 1. In a mold structure in injection molding in which a molded product is released from the movable mold 1 by an ejector pin 3, the fixed mold 2 is positioned on the side of the resin filling space at the time of resin injection, and the molded product is released at the time of release. A first mold member 2a that moves laterally or obliquely laterally, and a second mold member that is located on a surface of the resin-filled space that faces the movable mold and that is urged in the movable mold direction by a spring 2d. A mold member 2b;
It is fixed to the cylinder for injection molding, and the second
And a third mold member 2c that urges the movable mold 1 in the direction of the movable mold. When the molded product is released, the movable mold 1 is moved to move the movable mold 1 to the fixed mold. While separating from the mold 2, the first mold member 2a is moved to the side or obliquely to the side of the molded article, and the molded article is moved by the ejector pin 3 against the spring 2d to the second mold. The molded product is released from the movable mold 1 by moving with the mold member 2b.

According to a second aspect of the present invention, a slide surface for moving the first mold member 2a obliquely to the side of the molded product is provided on the second mold member 2b. Mold member 2a
Is moved along the slide surface.

[0008]

According to the first aspect of the present invention, when the molded product is released from the mold, the movable mold 1 is moved to separate the movable mold 1 from the fixed mold 2 and the first mold is removed. The mold member 2a is moved to the side or obliquely to the side of the molded product, and the molded product is moved by the ejector pin 3 against the spring 2d to the second position.
The molded product is released from the movable die 1 by moving the molded product together with the die member 2b.
The force of the pin 3 can be absorbed, and no excessive force is applied to the molded product. For this reason, it is possible to release the molded product having the thin portion without deforming or breaking the molded product.

In the invention of claim 2 of the present invention, the first
The second mold member 2b is provided with a slide surface for moving the mold member 2a to the oblique side of the molded product, so that the first mold member 2a is moved to the lateral side of the molded product at the time of mold release. The mechanism can be simplified, and the structure of the fixed mold can be simplified.

[0010]

FIG. 1 is a view showing a mold structure according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a movable mold, and 2 denotes a fixed mold. In the fixed mold 2, 2a is a first mold member which slides in the direction of the arrow at the time of mold release, 2b is provided with a slide surface with the first mold member on the side surface, and a resin injection The second mold member 2c having pores has a slide surface on the side surface on which the first mold member slides. One surface is in contact with the second mold member 2b, and the second mold member 2c is in the middle. A third mold member 2d provided with a small hole communicating with the resin injection hole of the mold member is a spring for urging the second mold member in the movable mold 1 direction.

Reference numeral 3 denotes an ejector pin, and reference numeral 4 denotes a cylinder. The resin injected from the cylinder 4 is supplied to the movable mold 1 through fine holes provided in the second and third mold members 2b and 2c. And a first mold member 2a and a second mold member 2b. FIG. 2 is a view showing a mold release process when injection molding is performed using the mold shown in FIG. 1. The same components as those shown in FIG. 1 are denoted by the same reference numerals. In the figure, reference numeral 5 denotes a molded product.
Next, a release process in injection molding using the mold of the present embodiment will be described with reference to FIG.

FIG. 1A shows a mold clamping → resin injection →
This shows a state in which pressure holding and cooling have been performed, and the mold is filled with resin. In order to release the molded product from the state shown in (a), first, as shown in (b), the movable mold 1 is moved to the left in the figure. As a result, the first mold member 2a of the fixed mold 2 slides along the slide surface as shown in the figure to release from the molded product, and is urged by the spring 2d. Mold member 2b is movable mold 1
Move with the molded product in the direction of.

In this state, the molded product 5 is pushed by the ejector pin 3 as shown in FIG.
Release the molded product. At this time, the surface of the molded product 5 opposite to the surface in contact with the ejector pin 3 is the second mold member 2b.
When the ejector pin 3 is pressed, the second
The mold member 2b moves rightward in the same figure against the spring 2d. For this reason, the force of the ejector pin 3 is absorbed by the spring 2d, and the molded product 5 can be released without applying excessive force. Then, as shown in FIG. 3D, the movable mold 1 further moves leftward in the figure, the first mold member 2a of the fixed mold 1 returns to the original position, and the molding is completed. I do.

In this embodiment, as described above, since the force of the ejector pin 3 can be absorbed by the spring 2d, no excessive force is applied to the molded product 5. Therefore, it is possible to release the molded product having the thin portion without deforming or damaging the molded product. Further, since the first mold member 2a is configured to slide on a slide surface formed on the second mold member 2b of the fixed mold 1, the first mold
A mechanism for pressing the mold member 2a from the side surface of the fixed mold 2 by a spring or the like in the mold direction, and a mechanism for holding the position when the first mold member 2a moves to a predetermined position. If provided, when the movable mold 1 moves to the position shown in FIG. 2B, the first mold member 2a can be slid to the position shown in FIG. ,
The first mold member 2a can be held at the position shown in FIG. Therefore, the mechanism of the fixed mold 2 can be simplified.

The first mold member 2a of the fixed mold 2
The mechanism for sliding is not limited to the above structure, and various other well-known mechanisms can be used. In the above embodiment, the first mold member 2a
The present invention is not limited to the above-described embodiment, and the first and second mold members 2a and 2b are not provided with a sliding surface. The mold member 2a may be configured to move in a direction orthogonal to the moving direction of the movable mold 1.

[0016]

As described above, according to the present invention, when the molded product is released from the mold, the movable mold is moved to separate the movable mold from the fixed mold, and the first mold is formed. By moving the member to the side or obliquely to the side of the molded product and moving the molded product together with the second die member against the above-mentioned spring by an ejector pin, the molded product is moved from the movable die. Since the mold is released, the force of the ejector pin can be absorbed by the spring at the time of release, so that no excessive force is applied to the molded product. For this reason, the molded product having the thin-walled portion can be released without being deformed or damaged, and the occurrence of defects at the time of releasing the thin-walled molded product can be significantly reduced as compared with the related art.

Further, by providing the second mold member with a slide surface for moving the first mold member obliquely to the side of the molded article, the first mold member is moved to the side of the molded article. The mechanism can be simplified, and the structure of the fixed mold can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a mold release process using a mold according to an embodiment of the present invention.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 movable mold 2 fixed mold 2a first mold member 2b second mold member 2c third mold member 2d spring 3 ejector pin 4 cylinder

Claims (2)

(57) [Claims] A movable mold (1) and a fixed mold (2) are provided, and resin is injected into a space formed by the movable mold (1) and the fixed mold (2). Then, the movable mold (1) is moved together with the molded product to separate the fixed mold (2) and the movable mold (1), and the ejector pins (3) penetrate the movable mold (1). ), The fixed side mold (2) is positioned on the side of the resin filling space during resin injection, and the molded article is released during mold release. A first mold member (2a) that moves to the side or oblique side of the resin filling space;
Second mold member biased in the movable mold direction by (2d)
(2b), fixed to the cylinder for injection molding, and
And a third mold member (2c) for urging the mold member (2b) in the movable mold direction. When the molded product is released, the movable mold (1) is moved to move the movable mold (1). The mold (1) is separated from the fixed mold (2), and the first mold member (2a) is moved to the side or oblique side of the molded product. Against the spring (2d)
A mold structure for thin-wall molding, wherein the molded product is released from the movable mold (1) by moving the molded product together with the second mold member (2b). 2. A second mold member (2b) is provided with a slide surface for moving the first mold member (2a) obliquely to the side of the molded product,
The mold structure for thin-wall molding according to claim 1, wherein the first mold member (2a) is moved along the slide surface when releasing the mold.