JPH0310015Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an injection mold. More specifically, the present invention relates to an injection mold suitable for manufacturing a molded product in which a metal insert is embedded. By using the injection molding die according to the present invention, the embedded position of the metal insert can be stabilized, and the incidence of defects in molded products can be drastically reduced.

``Prior art'' In order to manufacture molded products equipped with insert fittings for screw fastening, such as housings for electrical products such as radios, tape recorders, and televisions, electrical insulation materials, and household assembly products, it is necessary to Generally, an injection mold is used in which an insert guide pin is provided on the inner surface of the mold so as to protrude toward the cavity side. However, in actual molding operations, an insert mold is fitted onto this guide pin in advance by artificial or mechanical means, the mold is then clamped, molten resin is press-fitted into the cavity, and the resin is cooled and solidified. Afterwards, the mold is opened and the insert mold embedded in the resin molded product is pulled out from the insert guide pin when the molded product is released from the mold.

This will be explained based on FIG. 3, which shows a partially enlarged cross-sectional explanatory view of an example of an injection mold. female mold 3
An insert guide pin 31 is provided protruding toward the cavity side of the male mold 33, and an insert fitting 34 (a cap nut with a thread carved on the inside is shown) is fitted into the insert guide pin 31 of the male mold 33 (see Fig. 3). 1)), then the mold is clamped, and molten resin 35 is press-fitted into the cavity through a molten resin gate (not shown) (see Fig. 3 (2)). After that, melt resin 3
5 is solidified, the female mold 32 is moved back to open the mold, and the insert fitting 34 embedded in the resin molded product is pulled out from the insert guide pin 31 when the molded product is released from the mold, thereby producing a molded product with the insert fitting embedded therein. This is what you get.

"Problems to be Solved by the Present Invention" When manufacturing an injection molded product in which the above-mentioned insert fittings are embedded, the insert fittings 34 fitted into the insert guide pins 31 are It is inevitable that the fitting position will become unstable due to dimensional errors. For example, if the insert fitting 35 is not fitted in the correct position, the thickness of the resin portion covering it may become uneven, or the thickness of the resin portion covering the insert fitting may become uneven, or the insert may Even if the non-uniform thickness of the resin part covering the metal fittings is not noticeable, there is a problem in that the resin part becomes distorted when it is screwed to other parts during post-processing, causing it to crack during use. Further, if the molten resin gets around the cap nut side of the metal insert 35, there is a problem that it becomes difficult to screw the screw into the cap nut.

An object of the present invention is to provide an injection mold that eliminates the above problem of producing defective products by improving the structure of the insert guide pin.

``Means for Solving the Problem'' The gist of the present invention is to provide a groove with a center groove along the length direction, and to force the tip toward the outside with respect to the central axis of the insert guide pin. the insert guide pin for the inserted metal fitting,
The present invention relates to an injection mold for manufacturing a molded product in which an insert fitting is embedded, which is characterized by protruding from the cavity side of the injection mold.

"Operation" A biasing force acts on the groove of the insert guide pin outward with respect to the central axis of the insert guide pin, increasing its apparent diameter. Therefore, even if there is a dimensional error in the outer shape of the insert fitting or the cap nut, it can be inserted stably at a fixed position relative to the central axis of the insert guide pin, and the tip of the insert guide pin can be It can absorb the dimensional error of the cap nut and firmly hold the cap nut.

"Example" Hereinafter, an example of the present invention will be described based on the drawings, but the present invention is not limited to the following example as long as it does not go beyond the gist of the invention.

FIG. 1 is a partially enlarged cross-sectional explanatory view showing the male mold part of the injection mold according to the present invention, in which 3 is the male mold, 1 is the injection mold from the surface of the male mold 3. This is an insert guide pin that protrudes toward the cavity side. For this purpose, an insert metal fitting 4 such as a cap nut with a screw thread carved into the inside of the recess and a large number of uneven grooves carved into the outer wall in order to strengthen the retention by the molded resin is used. fitted by suitable means.

Reference numeral 6 denotes a groove provided in the vertical direction along the central axis of the insert guide pin 1. This divides the tip of the insert guide pin 1 into two halves, a and b, which extend outward with respect to the central axis. (indicated by arrow). That is, when the insert fitting 4 is fitted into this, even if there is a dimensional error in the cap nut, everything is stably and firmly fixed in a fixed position. Moreover, the metal insert 4 does not move due to the molten resin press-fitted into the injection molding cavity, and its embedded position in the molded product is stabilized, which is a major feature of the present invention.

FIGS. 2(1) to 2(4) are partially enlarged cross-sectional explanatory views illustrating the process of manufacturing a molded product in which an insert fitting is embedded using the injection molding die according to the present invention.

First, open the female mold 2 and prepare the insert fitting 4 between it and the male mold 3 equipped with the insert guide pin 1 toward the cavity side, and then fit the insert fitting 4 into the insert guide pin 1. (See Figure 2 (1) and Figure 2 (2)).Next, the mold is clamped and the molding resin 5 is press-fitted in a molten state through a gate (not shown) (See Figure 2 (3)). ,
After a certain period of time has passed and the molten resin is cooled and solidified,
The female mold 2 is moved back by opening the mold, and when the molded product is released, the insert fitting 4 embedded in the resin molded product is pulled out from the insert guide pin 1 to obtain a molded product (see Fig. 2 (4)). ).

In the above embodiments, an example has been described in which the insert guide pin 1 is provided in the male mold 3, but it is of course possible to have a configuration in which the insert guide pin 1 is provided in the female mold 2. The number of insert guide pins can be selected depending on the structure of the molded product to be manufactured.

``Effects'' As mentioned above, this invention improves the structure of the insert guide pin so that it can more firmly hold the insert fittings fitted into it, and is an injection molded product for manufacturing molded products with embedded insert fittings. It is a mold for molding. Therefore, even if there is a dimensional error in the insert metal fitting, the embedded position of the insert metal fitting is stable, and there is an advantage that the occurrence of defective molded products can be eliminated, and its industrial utility value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged sectional explanatory view of a male mold part showing an example of an injection mold according to the present invention, and Fig. 2 (1)
~(4) is achieved by the injection mold according to the present invention,
Figures 3 (1) and (2) are partially enlarged cross-sectional explanatory diagrams showing the process of manufacturing a molded product with embedded metal inserts.
It is a partially enlarged sectional explanatory view showing a process of manufacturing a molded product in which an insert fitting is embedded using a conventional injection mold. 1, 31...Insert guide pin, 2, 32
...Moving side mold, 3, 33... Fixed side mold, 4,
34...Insert metal fitting, 5, 35...Molding resin, 6...Intermediate groove.

Claims (1)

[Claims for Utility Model Registration] (1) An insert guide pin for an insert fitting that has a groove along its length and whose tip is biased outward with respect to the central axis of the insert guide pin. An injection mold for manufacturing a molded product, which is embedded with an insert fitting that protrudes from the cavity side of the injection mold. (2) Utility model registration claim No. (1) characterized in that the insert fitting is an insert nut
Injection mold as described in section.