JPH0414173Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a molding die, and particularly relates to an improvement of a molding die used for producing a molded body having a through hole.

[Conventional technology]

BACKGROUND OF THE INVENTION Molded polyurethane foam products are widely used as cushion materials for automobile seats, furniture seats, and the like. As an example,
FIG. 3 shows a cushion body used for the backrest of an automobile seat.

In the figure, 1 is a cushion body made of polyurethane foam. The top of the cushion body is provided with a hole for mounting a headrest. Further, a hole 3 penetrating from the front surface to the back surface is bored in the central portion of the cushion body. This through hole 3 is required as a seat belt through hole, a button hole, or the like.

By the way, in order to form the through hole 3 in the mold for manufacturing the cushion body, the mold shown in FIG.
The structure shown in B is adopted. That is, Fig. 4A
In this case, a projection 13 is provided that reaches from the molding surface of the lower mold 11 to the upper mold 12. In addition, in FIG. 4B, the lower mold 11
and a protrusion 14 on the molding surface of both the upper die 12 and the upper die 12, respectively.
15 so that the tips of both protrusions are in contact with each other. In either case, when a polyurethane foaming stock solution is injected into the molding chamber and mold foaming is performed, through holes are formed in the protruding portions.

[Problem that the invention seeks to solve]

In the case of a mold with the structure shown in Figure 4A,
It is not possible to completely prevent the foaming solution from entering between the projections 13 and the upper mold 12. The foaming pressure generated within the molding chamber facilitates this intrusion. As a result, as shown in FIG. 5A, a burr 4 that blocks the top of the through hole 3 is inevitably formed on the cushion body 1 formed by mold foaming. must be removed. This removal process is extremely troublesome and is a factor that hinders productivity improvement.

Similarly, in the case of the structure shown in FIG. 4B, the protrusions 14, 1
Since the foaming solution penetrates into the mating surfaces of the cushions 5, burrs 4' are formed on the resulting cushion body 1, as shown in FIG. 5B. In this case, since the burr 4' is formed in the middle of the through hole 3 as shown, the process of removing the burr becomes more troublesome and difficult.

In view of the above circumstances, the present invention aims to provide a molding die that can easily remove burrs that are inevitably formed covering the through holes when manufacturing a molded body having through holes. .

[Means for solving problems]

The molding die according to the present invention includes a lower mold and an upper mold that define a molding chamber having a shape corresponding to the intended molded product, and a lower mold or the upper mold that defines a through hole forming position of the intended molded product. and the other molding surface of the lower mold or the upper mold at the through-hole formation position of the intended molded product, such that the tip fits into the recessed hole. It is characterized by comprising a protrusion erected at the .

The present invention is particularly useful as a mold for foam molding of polyurethane foam, etc., but it is not limited to this, and can be used for any type of molded product having through holes. It can also be applied to molds.

[Effect]

In the mold of the present invention, the mating surface between the protrusion and the mold to form the through hole is inserted into the lower mold or the upper mold, so the manufactured molded product has burrs that block the through hole on the molded product surface. formed protruding from the outside. Therefore, burrs can be removed much more easily than when a conventional mold is used.

〔Example〕

FIG. 1A is a sectional view showing the main parts of a molding die according to an embodiment of the present invention. In the figure, 11 is a lower mold, and 12 is an upper mold. A protrusion 23 higher than the height of the molding chamber is erected on the lower mold 21 at the position where the through hole is to be formed in the target molded product, and the upper mold 22
A recessed hole 24 is formed in. The tip of the protrusion 23 and the recess 24 both have a rectangular cross-sectional shape, and as shown in the figure, the tip of the protrusion 23 is fitted into the recess 24 when the mold is closed. Note that this mold is constructed as a mold for manufacturing the cushion body shown in FIG. 3.

When a polyurethane foaming stock solution is injected into the molding chamber in the state shown in FIG. 1A and foam molding is performed, through-holes 3 are formed in the resulting cushion body 1 as shown in FIG. 1B, and A protruding burr 5 covering the through hole 3 is formed. Since the burr is formed by the foaming solution that has entered the mating surface of the protrusion 23 and the recessed hole 24, the burr 5 naturally protrudes from the molded surface of the cushion body 1. The burr 5 that protrudes in this way can be easily cut off with a cutter, for example. Therefore,
The process required for removing burrs is simplified, and productivity can be improved.

FIG. 2A is a sectional view showing the main parts of a molding die according to another embodiment of the present invention. In this embodiment, the tip of the protrusion 23' provided upright on the lower die 21 has a semicircular cross section, and the upper die 22 is also formed with a recess 24' having a corresponding cross section. . The rest of the configuration is the same as in the case of FIG. 1A. Therefore, when foam molding is performed, a burr 5' covering the top of the through hole 3 in a dome shape is formed in the resulting cushion body 1. Also in this case,
Since the burr 5' is formed to protrude outward from the surface of the cushion body, it can be easily removed as in the case of FIG.

In addition, in the above embodiments, in both cases, the lower mold 21
Protrusions 23, 23' are set upright on the upper mold 22, and recessed holes 2 are formed on the upper mold 22.
4, 24' was formed, but the protrusion was formed on the upper mold,
The same effect can be obtained by forming a recessed hole in the lower mold.

[Effect of idea]

As described in detail above, according to the molding die of the present invention, when manufacturing a molded body having a through hole, burrs that are inevitably formed covering the through hole can be easily removed. This can bring about significant effects such as improved productivity.

[Brief explanation of the drawing]

1 and 2 are views showing the structure and function of a mold that is an embodiment of the present invention, respectively, and FIG. 3 is an example of a molded product having a through hole for a backrest portion of an automobile seat. The perspective view and FIG. 4 are cross-sectional views showing the main structure of a conventional molding die, and FIG. 5 is a cross-sectional view showing the problems thereof. 3... Through hole, 5, 5'... Burr, 21... Lower die, 22... Upper die, 23, 23'... Protrusion, 24,
24'... Concave hole.

Claims (1)

[Scope of utility model registration request] A lower mold and an upper mold that define a molding chamber having a shape corresponding to the target molded product, and a molding surface formed on one of the molding surfaces of the lower mold or the upper mold at the through hole formation position of the target molded product. A concave hole and
A protrusion is provided on the other molding surface of the lower mold or the upper mold at a position where the through hole is to be formed in the intended molded product, and the protrusion is erected so that the tip thereof is fitted into the recessed hole. A mold for molding.