JP2002052581A - Mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding capable of precisely and efficiently molding a resin product having a rugged part in a through hole. SOLUTION: In the mold for molding an undercut resin product P having the rugged part Q in a mold drawing direction in the through hole (p), main slide cores 2 and sub-slide cores 3 are alternately disposed along an outer periphery of a central core 1, and outer rugged surfaces 2c and 3c in response to the rugged part of the hole are respectively provided at both the slide cores. The central cores and the main slide cores are provided at one side mold X of the fixed mold and the movable mold, and the sub-slide core is provided at the other side mold Y. At the mold opening time, the central core is solely retracted, the main slide core is slid to a central side of a first air gap A1 generated by the retracting of the center core to be separable. The sub-slide core is slid at the central side of a second air gap A2 generated by the release of the main slide core from the central core to enable an injection of the resin product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding of an undercut synthetic resin product having an uneven portion in a through hole.

[0002]

2. Description of the Related Art An undercut resin product having an uneven portion which is engaged in a through-hole in a through-hole in a through-hole is formed as an unfinished product having a thick peripheral wall, and is subsequently cut on the inner surface side of the thick peripheral wall. Processing was performed to form uneven portions. 53-42
No. 618, JP-B-59-14333, JP-A-59-150715, and JP-A-59-38032, the male part has a conical core core and the inclination direction of the slope of the core core. The first wedge-shaped core is divided into a first wedge-shaped core and a second wedge-shaped core, and the first wedge-shaped core is reduced toward the center side following the retraction of the core. There has also been proposed one in which a second wedge-shaped core is assembled in a space created by mold release and then released.

[0003]

SUMMARY OF THE INVENTION In a mold that collects and releases a wedge-shaped core toward the center following the retraction of a conical core, the retraction movement of the wedge-shaped core is prevented when the core is retracted. However, since it is necessary to be able to slide in the direction of inclination of the inclined surface of the core core, there has been a problem that the structure becomes complicated accordingly. Further, since all the wedge-shaped cores are released in the same direction, there is a problem that the arrangement side of the wedge-shaped core is complicated. Therefore, the present invention has been made in view of such problems of the prior art, and aims at precisely and efficiently undercut resin products having irregularities in the through holes. An object of the present invention is to provide a mold for injection molding that can be molded.

[0004]

In order to achieve the above object, an injection molding die according to the present invention is used for molding an undercut resin product having a concave / convex portion which is locked in a through-hole in a die-cutting direction. In the mold, a male part forming a through hole is composed of a center core, a main slide core and a sub slide core alternately arranged along the outer periphery of the center core, and both slide cores are formed of a resin product through hole. Equipped with an uneven outer surface corresponding to the uneven portion, the center core and the main slide core are provided on one of the fixed mold and the movable mold, and the sub slide core is provided on the other mold, and when the mold is opened. First, the center core retreats alone, the main slide core slides toward the center of the first space created by the retraction of the center core, and can be released, and the sub-slide core moves between the main slide core and the center core. Caused by mold release Slides toward the center of the second hollow portion to allow the injection of the resin product.

Here, the through hole of the resin product is not limited to a circular shape, but includes a non-circular shape. The concave and convex portions include a concave portion and a convex portion, a screw portion, etc. Refers to all the undercut parts that are locked to the part. Here, the male part refers to a part that forms a through-hole of a resin product, the center core refers to a part that is arranged at the center of the male part and first retreats when the mold is opened, and includes a main slide core and a sub slide. The slide cores are alternately arranged along the outer circumference of the center core, and after the main slide core slides toward the center of the first space created by the retreat of the center core, the sub slide core and the center slide core move together. It refers to a material that slides toward the center of the second space created by release from the core and releases the release. Here, the one-side mold and the other-side mold refer to a fixed mold and a movable mold, or a movable mold and a fixed mold.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an undercut resin product will be described with reference to FIG. 2. A resin product P has a through hole p, and a concave / convex portion Q is formed in the through hole p so as to be engaged in a die removing direction. As shown in FIG. 1, the injection mold used for molding the resin product P is a fixed mold 10, a movable mold 20, and a male mold 30.
The fixed mold 10 is provided with a plate receiving plate 15
And a cavity plate 1 forming an outer surface of the resin product P
6, the movable mold 20 is provided with a stripper plate 9,
The male part 30 includes a center core 1, a main slide core 2 and a sub slide core 3 that are alternately arranged along the outer periphery of the center core 1.

Next, a first embodiment of an injection mold according to the present invention will be described with reference to FIGS. 3 to 6. One of the fixed mold 10 and the movable mold 20 is one-side mold X. The other is a mold Y on the other side, and the main slide core 2 and the sub-slide core 3 constituting the male mold part 30 are formed by the uneven portions Q of the through holes p.
The center core 1 and the main slide core 2 are provided on the stationary mold 10 and the sub slide core 3 is provided on the movable mold 20. When the mold is opened, the center core 1 The main slide core 2 retreats singly and slides toward the center of the first space A1 generated by the retraction of the center core 1 so that the main slide core 2 can be released from the through hole p. The resin product P can be injected by sliding to the center side of the second space A2 generated by the release from the center core 1.

The center core 1 protrudes from the center in a radial direction from the center, and has one end attached to the plate receiving plate 15 of the fixed mold 10 and reciprocates toward the movable mold 20. The support portions 1a project in four directions at 90-degree intervals as shown in FIG. 10, and these are first to fourth support portions 1 for convenience.
1, 12, 13, and 14, the first to fourth support portions 11,
Receiving part 1 of main slide core 2 on the outer periphery of 12, 13, 14
b is provided.

The main slide core 2 is, as shown in FIG.
Main base 2a held on the front side of cavity plate 16
And a main core portion 2b inserted into the through hole p of the resin product P. The main core portion 2b is provided with a main uneven outer surface 2c corresponding to the uneven portion Q of the through hole p. 1a, the first to fourth support portions 11, 1
2, 13, and 14, respectively, and contact them with the first to fourth main slide cores 21, 21 for convenience.
2, 23, and 24, the sliding device 8 engaging with the main base 2a can slide in the direction perpendicular to the longitudinal movement of the center core 1 as shown in FIGS. When the portion A1 occurs, the main core portion 2b slides toward the center of the first empty portion A1, that is, separates from the uneven portion Q in the orthogonal direction.

As shown in FIG. 11B, the auxiliary slide core 3
It has a sub base 3a held on the front side of the core plate 5 and a sub core 3b inserted into the through hole p of the resin product P. The sub core 3b is continuous with the main uneven outer surface 2c of the main slide core 2. The first and fourth support portions 11, 12, 13, and 14 are provided with a sub-irregular outer surface 3c having a sub-irregular outer surface 3c as an outer edge, a side surface 3d and the other side surface 3e intersecting at approximately 90 degrees.
The first and fourth auxiliary slide cores 31, 32, 33, and 34 are provided for convenience, and are mainly provided by a slide device 18 that engages with the auxiliary base 3 a as shown in FIGS. 3 to 5. It becomes slidable similarly to the slide core 2, and the first to fourth sub slide cores 31, 32, 33, 34 are separated from the main slide core 2 and the center core 1 by the second empty space A2.
Occurs, the secondary core portion 3b slides toward the center of the second empty space A2, that is, separates from the uneven portion Q in the orthogonal direction.

Since the mold for injection molding of the first embodiment has the above structure, the center core 1 is preliminarily placed on the plate receiving plate 15, the main slide core 2 is placed on the cavity plate 16, and
The plate receiving plate 15 is provided with the auxiliary slide core 3 and the slide devices 8 and 18 are attached to the fixed mold 10 and the movable mold 20. When the fixed mold 10 and the movable mold 20 are clamped, As shown in FIGS. 1 and 3, the main slide core 2 and the sub slide core 3 of the male part 30 are connected to the center core 1 as shown in FIG.
The main uneven outer surface 2c of the main slide core 2 and the auxiliary uneven outer surface 3c of the sub slide core 3 are continuous with each other along the outer periphery of the main slide core 2 to form a cavity of the resin product P between the cavity plate 16 and the main plate.

After the molten resin is injected into the cavity and the molten resin is solidified, the mold is opened. First, as shown in FIG.
The plate receiving plate 15 and the cavity plate 16 are separated from each other, and accordingly, the center core 1 of the male mold portion 30 having one end fixed to the plate receiving plate 15 comes off alone, and the first empty space A1 is formed. After the formation of the first space A1, the first to fourth main slide cores 21, 22, 23, 24 are slid toward the center of the first space A1 by the slide device 8, and the first
The main core portions 2b of the fourth to fourth main slide cores 21, 22, 23, and 24 are separated from the concave / convex portion Q toward the center of the first empty space A1 as shown in FIG.

When the movable mold 20 is further retracted, and the core plate 5 and the stripper plates 9 and 19 are separated as shown in FIG. 5, the first to fourth main slides assembled at the center side of the first empty space A1. The cores 21, 22, 23, and 24 come out of the resin product P with the retreat of the movable mold 20, and accordingly, the second empty space A2 is formed. After the formation of the second empty space A2,
The first to fourth sub slide cores 31, 32, 33, 34 are slid toward the center of the second space A2 by the slide device 18, and the first to fourth sub slide cores 31, 32, 33, 3 are moved.
As shown in FIG. 9, the sub core portion 3b of FIG. 4 separates from the concave / convex portion Q toward the center of the second empty space A2 and gathers to make the injection of the resin product P free.

The difference between the second embodiment of the injection mold according to the present invention and the first embodiment will be described.
As shown in FIG. 12, the male part 30 is composed of a center core 1, a main slide core 2 and a sub slide core 3 alternately arranged along the outer periphery of the center core 1, and an insert 4 facing the main slide core 2. The center core 1 and the main slide core 2 are provided in a fixed mold 10, and the sub slide core 3 and the insert 4 are provided in a movable mold 20. It is inserted to the front side and is released by separating the core plate 5 and the stripper plates 9 and 19, and the other structure is the same as that of the first embodiment.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The slide dimension L of the main slide core 2 and the sub slide core 3 is equal to the difference T between the maximum internal dimension R and the minimum internal dimension r of the through hole p, that is, the internal / external difference T of the uneven portion Q, or When the main slide core 2 and the sub slide core 3 are retracted, the unevenness Q of the resin product P
It is desirable not to be locked. At the time of mold clamping, for example, one side surface 3d of the first
The other side surface 3e is in contact with the support portion 11 and one side surface of the first main slide core 21, and the other side surface 3e is in contact with the other side surface of the second support portion 12 and the second main slide core 22.
When 1, 2, 23, and 24 gather at the center of the first empty space A1, the first to fourth sub slide cores 31, 32, 33, 3
It is desirable that they are still inserted between the four.

The sliding means for the main slide core 2 and the sub slide core 3 is not limited to the above example. The main base 2a of the main slide core 2 and the sub base 3a of the sub slide core 3 are , 17, the slides of the main slide core 2 and the sub slide core 3 are further stabilized. The configurations of the fixed mold 10 and the movable mold 20 are not limited to the above embodiment, and the center core 1, the main slide core 2, and the sub slide core 3 constituting the male part 30 are provided.
Is not limited to four divisions, but can be divided into three to eight divisions. The center core 1 and the main slide core 2 can be provided on the movable mold 20 and the sub slide core 3 can be provided on the fixed mold 20. Achieve similar objectives. In the second embodiment, the insert 4 is provided on the stripper plate 9 to achieve substantially the same purpose even when the mold release is impossible.

[0017]

The injection mold according to the present invention has the same structure as described above, and has the following effects. Because the center core and the main slide core arranged along the outer periphery are provided on one of the fixed mold and the movable mold, and the sub slide core is separately provided on the other mold. Compared with the case where both slide cores are concentrated on one side mold or the other side mold, subdivision and arrangement become easier, and repair adjustment becomes easier. Moreover, since the main slide core and the sub slide core slide at right angles to the opening and closing direction of the mold, there is no need to press both slide cores when the center core is retracted. Is separated perpendicular to the concave and convex portions, so that no excessive force occurs at the time of separation, and as a result,
Even an undercut resin product having an uneven portion in the through hole can be easily and precisely molded.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic structure of an injection mold according to the present invention.

FIGS. 2A and 2B are longitudinal sectional views of a resin product.

FIG. 3 is a cross-sectional view of main parts at the time of mold clamping according to the first embodiment.

FIG. 4 is a sectional view of a main part when the main slide core slides.

FIG. 5 is a sectional view of a main part when the sub slide core slides.

FIG. 6 is a plan view showing an example of the arrangement of a male part and a slide device.

FIG. 7 is a plan view of a main part of the male mold part at the time of mold clamping.

FIG. 8 is a plan view of a main part of the male mold part when the main slide core is released from the mold.

FIG. 9 is a plan view of a main part of the male mold part when the auxiliary slide core is released from the mold.

FIG. 10 is a plan view of a center core.

11A and 11B are perspective views of a main slide core and a sub slide core.

FIG. 12 is a cross-sectional view of a main part of the second embodiment when the main slide core slides.

[Explanation of symbols]

 1 center core 2, 21, 22, 23, 24 main slide core 2a main base, 2b main core, 2c uneven outer surface 3, 31, 32, 33, 34 sub slide core 3a sub base, 3b sub core 3c Uneven surface 9, 19 Stripper plate 5 Core plate 6 Back plate 7, 17 Pressing plate 8, 18 Slide device 15 Plate receiving plate, 16 Cavity plate 10 Fixed mold, 20 Movable mold, 30 Male mold part X One side metal Mold, Y Mold on the other side A1 First void, A2 Second void P Resin product, p Through hole, Q Unevenness R Maximum internal dimension, r Minimum internal dimension L Slide dimensions of main slide core and sub slide core S Support width and core width T Difference between inside and outside of uneven part

Claims (1)

[Claims] 1. An undercut resin product (P) having a concave / convex portion (Q) to be locked in a through-hole (p) in a die-cutting direction.
In the molding die of (1), a male mold part (30) forming a through hole (p) comprises a center core (1) and a main slide core (2) alternately arranged along the outer periphery of the center core (1). The slide cores (2, 3) are provided with concave and convex outer surfaces (2c, 3c) corresponding to the concave and convex portions (Q) of the resin product through-hole (p), and the center core (1). ) And the main slide core (2) are one side mold (X) of the fixed mold (10) and the movable mold (20).
In addition, a sub slide core (3) is provided on the other mold (Y), and when the mold is opened, first, the center core (1) retreats alone, and the main slide core (2) retreats the center core (1). The auxiliary slide core (3) slides to the center side of the first empty space (A1) generated by the main slide core (3), and the secondary slide core (3) is released from the main slide core (2) and the center core (1). An injection molding die, characterized in that the resin product (P) can be injected by sliding toward the center of the two empty portions (A2).