JP2001191373A - Mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold an undercut part being inside a molded product even in the case where there is not a margin for a space inside the molded product. SOLUTION: For a mold 10, a core insert die 25 for molding an undercut part 3 and a center core 25 for setting the core insert die 25 at a molded position of the undercut part 3 are equipped to a side for molding an inside of the molded product 1. An ejection pin 27 for ejecting the core insert die 25 from the undercut part 3 is provided onto a side for molding an outside of the molded product 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a mold.

[0002]

2. Description of the Related Art When an injection molding die has an undercut portion inside a molded product (inside of a cap or the like, which is surrounded by a side wall), a slide core for molding the undercut portion is attached to the molded product. Extending from inside to outside,
The slide core is provided with an angular pin that engages obliquely with the mold opening direction, and the slide core can be moved to a position that does not interfere with the undercut portion when the mold is opened.

[0003]

The above-mentioned slide core cannot be adopted when there is no more than a certain space inside the molded product.

An object of the present invention is to make it possible to mold an undercut portion inside a molded product even when there is no space inside the molded product.

[0005]

According to the present invention, there is provided a mold for a molded product having an undercut portion on the inside thereof, wherein an undercut portion is provided on a side on which the inside of the molded product is molded. A core insert for molding the core insert and a center core for setting the core insert at the molding position of the undercut portion, and an extrusion pin for extruding the core insert from the undercut portion on the side for molding the outside of the molded product. It is intended to be prepared.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 4, an injection mold 10 has a molded article 1 made of, for example, a hinge cap (consisting of a base cap 1A and a cover cap 1B). There is an undercut portion 2 formed by the nozzle portion 1C outside the side wall of 1A, and an undercut portion 3 formed by a concave portion on the back surface of the nozzle portion 1C inside the side wall of the base cap 1A. The nozzle portion 1C is oblique to the central axis of the base cap 1A, and the undercut portions 2, 3 are also oblique to the central axis of the base cap 1A.

The mold 10 is configured such that the fixed-side cavity 11 and the movable-side core block 21 are separated by a parting line P.D. L allows each other to open and close.

The mold 10 is provided with a base cap 1A in a cavity 11 (the side on which the outside of the base cap 1A is molded).
And a slide core 12 for forming the undercut portion 2 outside of the slide core. When the mold is closed, the slide core 12 is in the advanced position and forms the molding surface of the undercut portion 2 of the base cap 1A. When the mold is opened, the slide core 12 is moved to a position where it does not interfere with the undercut portion 2 by a mold opening force or a cylinder. (FIG. 4).

The mold 10 includes a core A22, a core B23, an ejector sleeve 24 on a core block 21 (the side on which the inside of the base cap 1A is formed), and also forms an undercut 3 inside the base cap 1A. And a center core 26 for setting the core insert 25 to the molding position of the undercut portion 3 when the mold is closed. Core nest 25 and center core 26 are each core A
Are accommodated in the hollow portions 22A and 22B. Center core 2
6 has a taper surface 26A which moves back and forth in the center axis direction of the base cap 1A along the hollow portion 22B by a mold opening force or a cylinder, etc., and abuts against the taper surface 25A of the core insert 25. Converted into oblique movement along the hollow portion 22A of the core insert 25 through the surfaces 25A and 26A,
At the advanced position, the core insert 25 is pushed into the molding position of the undercut portion 3 (FIG. 1), and at the retracted position, separated from the core insert 25 (FIG. 2).

The mold 10 is provided with a base cap 1A in a cavity 11 (the side on which the outside of the base cap 1A is molded).
And an extruding pin 27 for extruding the core insert 25 from the undercut portion 3 on the inside. The extrusion pin 27 is built in the slide core 12, and when the mold is closed, is pushed against the above-described core insert 25 set at the molding position of the undercut portion 3 so that the nozzle portion of the base cap 1A can be molded (FIG. 1) When the mold is opened, the core insert 25 is protruded by a spring 28 built in the slide core 12 to push the core insert 25 from the undercut portion 3 to a position where the core insert 25 does not interfere with the undercut portion 3.

Accordingly, the molding operation of the mold 10 is as follows. (1) When closing the mold in which the cavity 11 and the core block 21 are in contact with each other, the slide core 12 on the side of the cavity 11, the core A22, the core B23, the ejector sleeve 24, and the core insert 25 on the side of the core block 21 as shown in FIG. After setting, the molded product 1 having the undercut portions 2 and 3 in the base cap 1A is injection-molded. At this time, the core insert 25 is set at the molding position of the undercut portion 3 by the center core 26.

(2) The center core 26 is moved by a mold opening force or the like to separate the center core 26 from the core insert 25 (FIG. 2). At the same time, the push pin 27 is protruded by the spring 28 to push the core insert 25 from the undercut 3 inside the base cap 1A to a position where it does not interfere with the undercut 3 (FIG. 3).

(3) The slide core 12 and the push-out pin 27 are removed from the undercut portion 2 outside the base cap 1A to a position where they do not interfere with the undercut portion 2 by a mold opening force or the like (FIG. 4), and a core block is formed. The mold 21 is opened from the cavity 11 together with the molded product 1 and separated therefrom.

(4) The molded product 1 is extruded from the core block 21 together with the core A22 by the ejector sleeve 24 together with the core B23, and then the ejector sleeve 24 is further extruded so that the molded product 1 can be taken out.

After taking out the molded product 1, the core B23 and the ejector sleeve 24 are returned to the core block 21 and again.
Wait for operation preparation of (1).

When the screw 4 is formed on the molded article 1,
It is possible to form a screw having a hollow shape.

(According to Claim 1) A core insert 25 for forming the undercut portion 3 and a center core 26 are placed on the side where the inside of the molded product 1 is formed. Therefore, molded article 1
The undercut portion 3 inside the molded product 1 can be formed even when there is no room for space inside.

[0018]

As described above, according to the present invention, the undercut portion inside the molded article can be molded even when there is no room inside the molded article.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a closed state of a mold.

FIG. 2 is a sectional view showing a center core moving state.

FIG. 3 is a cross-sectional view showing a state where a core insert is pushed out.

FIG. 4 is a sectional view showing a slide core moving state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molded product 3 Undercut part 10 Die 25 Core insert 26 Center core 27 Extrusion pin

Claims (1)

[Claims] 1. A mold for a molded product having an undercut portion inside, wherein a core insert for molding an undercut portion, and a core insert undercut are formed on a side for molding the inside of the molded product. A mold comprising: a center core set at a molding position of a molding part; and an extrusion pin for extruding a core insert from an undercut part on a molding side of a molded product.