JPH0353863Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a mold for forming a urethane foam having a hole in the center.

(Prior Art) Conventionally, a urethane foam 12 with a hole 10 in the center as shown in FIG.
A mold having a columnar protrusion 16 for forming a hole 10 in the center of the mold surface of No. 4 is used, a urethane foam raw material 20 is injected into the cavity 18, and the raw material is foamed in the cavity after closing the mold. It is being carried out.

(Problems to be Solved by the Invention) When molding urethane foam using a mold, it is preferable to perform single-point injection with a fixed injection position from the viewpoint of molding operations. However, in the case of the mold, single-point injection makes it difficult to uniformly disperse the raw material 20 into the cavity 18;
Not only is it difficult to obtain a urethane foam of uniform quality, but there is also the problem that the urethane foam is likely to have insufficient thickness.

Therefore, in the case of the mold, the cavity 18
In order to uniformly disperse the raw material 20 inside, the raw material 20 must be injected while moving the injection position, making the operation complicated.

This invention aims to solve the above-mentioned problems, and aims to provide a mold that can uniformly disperse raw materials into the cavity even by single-point injection.

(Means for solving the problem) This invention is a split-type mold for molding urethane foam with a hole in the center. The above-mentioned problem is solved by providing a columnar projection formed by gradually enlarging the hole for forming the hole, and providing a plurality of vertical grooves radially on the side surface of the enlarged portion.

(Function) Injecting the raw material of urethane foam into the lower mold,
This is done by discharging the raw material onto the upper end of a columnar projection protruding from the surface of the lower mold. The discharged raw material flows along the side surface of the columnar projection and flows into the cavity around the columnar projection. At this time, since the diameter of the columnar protrusion gradually increases from the upper end of the columnar protrusion to the middle of the upper part, the raw material is dispersed around the columnar protrusion due to its expanded shape. Moreover, since vertical grooves are radially provided on the side surface of the enlarged portion, the raw material is uniformly dispersed around the columnar projections by the vertical grooves. As a result, the raw material can be uniformly dispersed within the cavity even with single-point injection, and the urethane foam with a hole in the center is of good quality and has a good appearance with no missing parts. can be molded.

(Example) This invention will be explained below based on an example using drawings.

FIG. 1 is a perspective view showing an example of a urethane foam mold according to this invention.

The illustrated mold consists of a lower mold 22 and an upper mold 24, and has a cavity 26 that has the same shape as the desired molded product when the mold is closed.

The lower mold 22 is provided with columnar projections 28 on its mold surface up to the upper mold 24 mold surface. The columnar projection 28 has a diameter that gradually increases from the upper end to a predetermined position below, and a plurality of vertical grooves 32 are radially provided on the side surface of the enlarged portion 30. This columnar projection 28 is for forming the hole 10 in the urethane foam 12. The position of the lower end of the enlarged shaped portion 30 is set to an optimum position depending on the shape of the cavity 26 and the like.

FIG. 2 is a sectional view showing the process of molding urethane foam using the mold. The urethane foam is formed by discharging the urethane foam raw material 20 onto the upper end of a columnar projection 28 protruding from the surface of the lower mold 22, and then closing the upper mold and the lower mold. 34 is a nozzle for injecting the urethane foam raw material.

The raw material 20 discharged to the upper end of the columnar protrusion 28 flows along the enlarged portion 30 of the columnar protrusion and flows into the cavity 26 while being dispersed around the columnar protrusion 28 . Furthermore, the dispersion becomes uniform due to the radial vertical grooves 20 provided on the side surface of the enlarged shape portion 30. As a result, the urethane foam with a hole in the center, which is formed by the foaming reaction of the raw material 20 in the mold, is of uniform quality and has a good appearance with no underfill. After the foaming reaction is complete, the molded product is removed from the mold.
Urethane foam molded product with a hole in the center 1
2 is obtained.

Note that, depending on the use of the molded product, an insert is appropriately placed in the mold.

(Effect of the invention) This invention has a shape whose diameter is gradually enlarged from the upper end to a predetermined position below, and a columnar protrusion with vertical grooves radially provided on the side surface of the enlarged part is provided on the lower mold surface. be. Therefore, even when injecting at a single point to the upper end of a columnar projection, the injection material is dispersed around the columnar projection by the enlarged shape, and the radial vertical grooves on the side surface of the enlarged shape also ensure uniform distribution. , raw materials can be uniformly injected into the cavity.

Therefore, by using the mold of this invention, it is possible to mold a urethane foam with a hole in the center that has uniform quality and a good appearance with no missing parts even by single-point injection, which is extremely effective. Work becomes easier.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a mold according to an embodiment of this invention, Fig. 2 is a sectional view showing urethane foam molding using the mold according to this invention, and Fig. 3 is a perspective view of a urethane foam with holes. , FIG. 4 is a sectional view of the lower mold of a conventional mold. 22... Lower mold, 24... Upper mold, 26... Cavity, 28... Columnar projection, 30... Enlarged shape part,
32...Vertical groove.

Claims (1)

[Scope of utility model registration request] In a split-type mold for molding urethane foam with a hole in the center, the hole is formed by forming a columnar protrusion on the mold surface of the lower mold with a diameter gradually increasing from the upper end to a predetermined position below. 1. A urethane foam molding mold, characterized in that a plurality of longitudinal grooves are provided radially on the side surface of the expanded shape part.