JPS5937209B2 - Manufacturing method of box-shaped synthetic resin molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding deep box-shaped items such as automobile glove boxes using synthetic resin.

The glove box of an automobile has a deep box shape, and in order to mold it, a male mold 1 is used as shown in Figure 1.
A method is adopted in which a synthetic resin is injected into the gap 3 between the male mold 1 and the female mold 2, and the resin is cured to form the mold.

However, when the depth of the product is deep, it is difficult to hold the male mold 1 and the female mold 2 so that the thickness of the gap 3 is uniform, especially when the injection pressure of the material (synthetic resin) is high. Male mold 1 inevitably moves.

For this purpose, conventionally, as shown in FIG. 1, a boss portion 1a with a circular cross section for positioning is provided protruding from the tip of the male mold 1, and a recess portion 2a with a circular cross section into which the boss portion 1a fits is provided on the female mold. The boss part 1
A is fitted into the recess 2a to hold the male die 1 relative to the female die 2 so that the position thereof does not move.

However, the product obtained by such a conventional method has a hole in the boss portion 1a, and although the hole is small, it is not preferable when used as a storage container.

The present invention provides a method for manufacturing a box-shaped resin molded product that eliminates the above-mentioned conventional problems. That is, in the present invention, as shown in FIGS. 2 and 3, the boss portion 1a to be fitted into the recess 2a having a circular cross section has a square cross section,
The structure is such that a predetermined gap 4 is formed between the circumferential surface of the boss 1a and the inner circumferential surface of the recess 2a when the boss 1a is fitted, and a predetermined gap 5 is also formed between the tip of the boss 1a and the bottom of the recess 2a. Allow to form.

As mentioned above, the boss part 1a of the male mold 1 and the recess part 2a of the female mold 2
, the outer peripheral corner of the boss portion 1a is almost inscribed in the inner peripheral surface of the recess 2a, and the intended purpose of positioning the male mold 1 relative to the female mold 2 and holding the same can be achieved sufficiently. When material is injected into the part 3, the material passes through the gap 4 and also enters the gap 5, so that the gaps 4 and 5 are also filled with the material.

A product is obtained by curing the material (synthetic resin), and as shown in FIG. 4, the product according to the present invention has a protrusion B having a cylindrical outer shape corresponding to the recess 2a on the main body A (the portion of the gap 3). , and the peripheral surface of the protrusion B has only a linear extremely thin wall portion formed at the corner of the boss portion 1a, so that it does not become a problem as a storage case like in the past. No holes are formed.

In the illustrated embodiment, the boss portion 1a has a substantially quadrangular prism shape, but any prism shape such as a triangular prism or a pentagonal prism can be adopted.Alternatively, the concave portion 2a may have a square cross section and the boss portion 1a may have a cylindrical shape. can be accomplished.

As described above, according to the present invention, the fitting between the positioning boss part and the recess of the male mold and the female mold is such that one has a circular cross section and the other has a square cross section, and the gap created by the inscribed relationship between the circle and the corner is By flowing the material into the gap at the tip of the boss, it is possible to securely position and hold the male die relative to the female die, and to obtain a box-shaped product with no holes.

[Brief explanation of the drawing]

FIG. 1 shows a conventional mold, in which Figure A is an overall sectional view and Figure 1 is a sectional view taken along line X-X in Figure A. Figure 2 is a cross-sectional view of the main parts of the mold used in the method of the present invention;
FIG. 3 is a sectional view taken along YY line in FIG. 2, and FIG. 4 is a sectional view of a main part of a product molded according to the present invention. 1...Male type, 1a...Boss part, 2...Female type, 2a
...Concavity, 3...Gap, 4,5...
...Gap, A...Product body, B...
・Protrusion cut.

Claims (1)

[Claims] 1. A method for obtaining a box-shaped product by injecting a synthetic resin into the gap between a male mold and a female mold and curing it, in which a positioning boss protrudes from the tip of the male mold and the boss is inserted into the mold. A recess formed in the female shape to prevent the male mold from moving is formed so that one side has a square cross section and the other has a circular cross section, and the gap created by the inscribed relationship between the circle and the corner forms a boss. A method for manufacturing a box-shaped synthetic resin molded product, characterized in that a synthetic resin is flowed and filled into a gap at the tip of the part, and after the synthetic resin hardens, a protrusion is formed on the box-shaped product by fitting a boss part and a recess.