JPH1177761A - Injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release securely a slide core forming an undercut section of a synthetic resin molded product from the synthetic resin molded product. SOLUTION: A slide core 13 forming an undercut section of a synthetic resin molded product is disposed to slide on a mold main body with the given cavity formed of a core mold 11 and a cavity mold 12. A through-hole 13e is so formed in the slide core 13 as to run through in the slide direction of the slide core 13, and a slide pin 14 runs through inside the through-hole 13e, and the slide core 13 can be slid along the slide pin 14. When the slide core 13 is slid in the direction of being released from the synthetic resin molded product, the end of the slide pin 14 is protruded from the through-hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die used for molding a synthetic resin molded product having an undercut portion, and in particular, a slide core forming an undercut portion is formed on a synthetic resin molded product. The present invention relates to an injection mold that can be easily released from the mold.

[0002]

2. Description of the Related Art In molding a synthetic resin molded article having an undercut portion, for example, an injection molding die in which an undercut portion is formed by a slide core is used. Such an injection molding mold has a mold body constituted by a core mold having a male part and a cavity mold having a female part fitted to the male part. A cavity is formed to be filled with the molten resin. The slide core forming the undercut portion of the synthetic resin molded product is slidably disposed with respect to the mold body.

In such an injection mold, the cavity is filled with a molten resin while the slide core is slid and arranged at a predetermined position. When the molten resin filled in the cavity is solidified, the slide core is slid so as to be released from the synthetic resin molded product.
When the slide core is released from the synthetic resin molded article, the core mold and the cavity mold of the mold body are opened, and the solidified synthetic resin molded article is taken out.

[0004]

In such an injection molding die, the synthetic resin molded product is in close contact with a slide core for forming an undercut portion due to shrinkage when the synthetic resin molded product is solidified. And the slide core may not be easily released from the synthetic resin molded product.

In an injection mold, an ejector pin for projecting a synthetic resin molded product from a cavity is usually used in order to release the synthetic resin molded product in a state where a mold main body constituted by a core mold and a cavity mold is opened. Is provided, and when the mold is opened, the ejector pins are operated by a hydraulic circuit.However, since the slide core is not provided with such an ejector pin, the slide core is not provided. It is not easy to release from a synthetic resin molded product.

In order to easily release the slide core from the synthetic resin molded product, a configuration is employed in which the slide core is pressed against the synthetic resin molded product by a spring such as a coil spring. In this case, at the time of molding, the slide core is strongly pressed against the slide core by the spring, but when the slide core is released from the synthetic resin molded product, the slide core is pressed by the repulsive force of the spring. The slide core can be slightly separated from the synthetic resin molded product, whereby the slide core can be reliably released from the synthetic resin molded product.

[0007] When the undercut portion penetrates the synthetic resin molded product, the slide core is pressed by a spring so as to be in close contact with the inner surface of the mold. By the repulsion of
The slide core can be easily released from the synthetic resin molded product.

However, if the slide core has a large shape, it may not be possible to reliably release the slide core from the synthetic resin molded product due to the repulsive force of the spring. Further, a constant repulsive force is not always obtained by the spring, and therefore, there is a possibility that the slide core cannot be reliably released from the synthetic resin molded product. Furthermore, depending on the shape of the undercut portion of the synthetic resin molded product, there is a possibility that a spring or the like for pressing the slide core against the synthetic resin molded product may not be provided. It is not easy to release from the product.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to form a slide core for forming an undercut portion from a synthetic resin molded product without using a spring such as a coil spring. An object of the present invention is to provide an injection mold that can be released from the mold.

[0010]

According to the injection mold of the present invention, an undercut portion of a synthetic resin molded product is formed in a mold body having a predetermined cavity formed by a core mold and a cavity mold. A slide core is an injection molding die slidably disposed, a through hole provided in the slide core so as to penetrate in the slide direction of the slide core, and a slide pin inserted through the through hole. The slide core is configured to be slidable along the slide pin, and when the slide core is slid in the direction of releasing from the synthetic resin molded product, the tip of the slide pin projects from the through hole. It is characterized by the following.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part showing an example of an embodiment of an injection mold according to the present invention. The injection mold 10 is used for manufacturing a synthetic resin molded product 20 shown in FIG. The synthetic resin molded product 20 has a vertical portion 21 extending vertically and a horizontal portion in which one side portion extends to the side of the vertical portion 21 so as to be orthogonal to the vertical portion 21 above the vertical portion 21. And a horizontal portion 22 arranged. The horizontal portion 22 has a hollow rectangular parallelepiped shape having a concave portion 22a opened on the upper surface, and its front and rear surfaces are elongated in the left-right direction. The vertical portion 21 has undercut portions 21a and 21b, which are a pair of upper and lower concave portions separated by a horizontal partition 21c at the center in the vertical direction, and each of the undercut portions 21a and 21b has an opening doing. Each undercut 21a and 21b
A short columnar boss 21d protruding forward is provided at the center of the front surface of the horizontal partition 21c provided between the bosses 21d.

As shown in FIG. 1, the injection molding die 10 of the present invention for molding such a synthetic resin molded product 20 has a concave portion 22a of a horizontal portion 22 in the synthetic resin molded product 20 with respect to a flat surface 11b. A core mold 11 having a male part 11a having a shape corresponding to the internal shape of the core mold 11 and a cavity mold 1 arranged in an opposed state with the male part 11a of the core mold 11 interposed therebetween.
2 and a slide core 13. Core type 11
And the cavity mold 12 constitutes a mold main body which is mutually clamped and opened.

The cavity mold 12 is provided with a female part 12a that fits into the male part 11a of the core mold 11 on a flat surface 12b that abuts against the flat surface 11b of the core mold 11, and the female part 12a The male portion 11a of the mold 11 is fitted so as to form a cavity corresponding to the rear surface of the horizontal portion 22 of the synthetic resin molded product 20, and the flat surface 12b is abutted against the flat surface 11b of the core mold 11. . The female part 12a of the cavity mold 12 is also opened on a flat surface 12c orthogonal to the flat surface 12b.

The inner surface of the female portion 12a of the cavity mold 12 includes a rear surface of the horizontal portion 22 of the synthetic resin molded product 20, a rear surface of a vertical portion 21 continuous with the rear surface of the horizontal portion 22, and left and right sides of the horizontal portion 22. They correspond to the respective end faces, the bottom surface of the horizontal portion 22, and the left and right side surfaces and the bottom surface of the vertical portion 21, respectively. The cavity mold 12 is slid with respect to the core mold 11 in the protruding direction of the male portion 11a, that is, in the depth direction of the concave portion 22a of the horizontal portion 22 in the synthetic resin molded product 20, and is moved into the female portion 12a of the cavity mold 12. The mold body is clamped so that the male part 11a of the core mold 11 is fitted.

The slide core 13 has a flat surface 13b along the flat surface 11b of the core mold 11.
Are slidably arranged along the flat surface 11b of the. The slide core 13 slid along the flat surface 11b of the core mold 11 is configured such that the flat surface 13c abuts on the flat surface 12c of the cavity mold 12. When the flat surface 13c of the slide core 13 abuts against the flat surface 12c of the cavity die 12, a cavity corresponding to the front surface of the horizontal portion 22 of the synthetic resin molded product 20 is formed together with the male portion 11a of the core die 11. It has become so.

The slide core 13 includes a cavity mold 12.
In the female portion 12a, a convex portion 13a fitted adjacent to the male portion 11a of the core mold 11 is provided. Convex part 13a
Has an outer surface similar to the inner surfaces of the undercut portions 21a and 21b of the vertical portion 21 of the synthetic resin molded product 20, and has the male portion of the core mold 11 fitted into the female portion 12a of the cavity mold 12. 11a is a state in which a cavity corresponding to the bottom surface of the horizontal portion 22 located on the vertical portion 21 of the synthetic resin molded product 20 is formed, and the female portion 12a of the cavity mold 12 is In this state, cavities corresponding to the rear surface and the left and right side surfaces of the vertical portion 21 are formed. A cavity 13 d corresponding to the partition 21 c of the vertical portion 21 of the synthetic resin molded product 20 is provided in the protrusion 13 a of the slide core 13.

The slide core 13 has a through hole 13e penetrating in parallel with the flat surface 11a of the core die 11. The through hole 13 e is formed in the protrusion 1 of the slide core 13.
The slide pin 14 is slidably inserted through the through hole 13e in communication with the center of the cavity 13d in 3a. The head of the slide pin 14 is supported by a support 15 attached to the core mold 11, and the head of the slide pin 14 is fixed to the support 15 by a fixture 16 attached to the support 15. I have.

The slide core 13 slides along a slide pin 14 whose head is fixedly supported by a support 15, and the slide core 13 is placed on the flat surface 12 c of the cavity mold 12. When the slide pins 14 are brought into contact with each other, the front end surface of the slide pin 14
d is kept in a state where a slight gap is provided. Therefore,
The through hole 1 between the cavity 13d provided in the protrusion 13a of the slide core 13 and the tip end surface of the slide pin 14
A space corresponding to the boss portion 21d of the synthetic resin molded product 20 is formed in 3e.

In the injection mold 10 having such a structure,
In a state where the female part 12a of the cavity mold 12 is fitted to the male part 11a of the core mold 11 and the mold body is clamped, the slide core 13 is moved along the slide pin 14 attached to the core mold 11. Is slid in a direction approaching the cavity mold 12. Then, the projection 13a of the slide core 13 is fitted into the female portion 12a of the cavity mold 12 adjacent to the male portion 11a of the core mold 11, and the flat surface 12c of the cavity mold 12 is Flat surface 1
3c is matched.

In such a state, the cavity mold 1
Male part 11a of core mold 11 fitted in female part 12a
The space between the convex portion 13a of the slide core 13 and the female portion 12a of the cavity mold 12 is filled with a molten resin. The female part 12a of the cavity mold 12 and the male part 11 of the core mold 11
a and the molten resin filled between the protrusion 13a of the slide core 13 is also filled in the cavity 13d provided in the protrusion 13a of the slide core 13, and slides in the through hole 13e of the slide core 13. The space between the pin 14 and the tip surface is also filled.

When the molten resin is solidified in such a state, the slide core 13 moves along the slide pin 14
It is slid in a direction away from the cavity mold 12. When the slide pin 14 is slid, the slide pin 14
Of the synthetic resin molded product 20 formed by filling the tip end surface of the slide core 13 into the through hole 13e.
1d, press the slide pin 1
4 protrudes from the through hole 13e. As a result, the protrusion 13a of the slide core 13 is
4 is smoothly released from the inside of the undercut portions 21a and 21b of the synthetic resin molded product 20 against which the front end surface is pressed.

In this case, since the synthetic resin molded article 20 is formed with the cylindrical boss 21d against which the distal end surface of the slide pin 14 is abutted, the synthetic resin molded product on which the distal end surface of the slide pin 14 is pressed. The article 20 has no risk of deformation such as turning up, cracks, and the like, and also has no risk of whitening. The boss 21d preferably has a projection length of about 1 to 2 mm so that deformation or the like does not occur when the distal end surface of the slide pin 14 is pressed, but is usually 0.2 mm or more. What is necessary is just to become the protrusion length.

If the boss portion 21d cannot be formed at the center of the partition 21c depending on the shape of the synthetic resin molded product 20, etc., the through-hole 13e is formed in the proper position of the synthetic resin molded product 20. When the through hole 13e is provided in the slide core 13 so as to oppose the one end of the partition 21c, the boss 21d is provided at one end of the partition 21c. Formed in the part.

When the slide core 13 is slid along the slide pins 14 to release the slide core 13 from the synthetic resin molded product 20, the cavity mold 12
Is slid in a direction away from the core mold 11, the mold body is opened, and the synthetic resin molded product 20 is released.

[0026]

As described above, the injection molding die of the present invention
When the slide core forming the undercut portion of the synthetic resin molded product is slid along the slide pin to release the slide core from the synthetic resin molded product, the slide pin protrudes from the slide core to remove the synthetic resin molded product. In order to press, the slide core can be reliably released from the synthetic resin molded product.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an example of an embodiment of an injection mold according to the present invention.

FIG. 2 is a perspective view of a synthetic resin molded product molded by the injection molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injection molding die 11 Core mold 11a Male part 11b Flat surface 12 Cavity mold 12a Female part 12b Flat surface 12c Flat surface 13 Slide core 13a Convex part 13b Flat surface 13c Flat surface 13d Cavity 13e Through hole 14 Slide pin 15 Support 16 Fixture

Claims (1)

[Claims] 1. An injection molding die in which a slide core forming an undercut portion of a synthetic resin molded product is slidably disposed with respect to a die main body in which a predetermined cavity is formed by a core die and a cavity die. A slide hole is provided in the slide core so as to penetrate in the slide direction of the slide core, and a slide pin inserted through the through hole allows the slide core to slide along the slide pin. Wherein the slide core is slid in a direction in which the slide core is released from the synthetic resin molded article, so that the tip of the slide pin projects from the through hole. Type.