JPH07260Y2 - Mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to, for example, a mold for a rubber product, and more particularly to a mold for a molded product having a through hole.

(Prior Art) As a conventional molding die of this type, there is, for example, one shown in FIG. That is, the molding die 100 is an upper die 101.
A cavity 103 is formed between the mating surfaces of the lower mold 102 and the lower mold 102, and the core 10 protruding into the cavity 103 is formed in the lower mold 102.
4 are provided. The core 104 has its tip abutted against the upper mold 101 in a mold closed state, so that the core 104 forms a through hole 106 in a molded product 105 as shown in FIGS. 8 and 9. It has become.

(Problems to be solved by the invention) However, in the above-mentioned conventional mold structure, the molding material enters as a flash in the gap between the core 104 and the upper mold 101, and a thin film remains in the required through hole 106, resulting in a molded product. After the vulcanization molding of 105, finishing work was required to remove this thin film by hand or by using a razor or the like.

Therefore, the finishing process increases and the cost increases, and
Unperforated products that have been forgotten to finish may be mixed with good products. Furthermore, in the case of hand finishing in which the burrs are peeled off by hand, variations occur in the remaining burr.

The present invention has been made to solve the above-mentioned problems of the prior art. The purpose of the present invention is to enable deburring of a through hole at the same time as deburring of an injection gate to reduce the finishing process after molding. Another object of the present invention is to provide a molding die that can be formed and can reduce the amount of flash residue.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a hollow cavity is formed between the mating surfaces of the upper die and the lower die, and the lower die projects into the cavity. In a molding die in which a tip of the core reaches the upper die, and a through hole is formed in the molded product by the core, a core tip surface at the time of mold closing at a portion corresponding to the core tip of the upper die It is characterized in that it is provided with an injection gate which is closed by.

(Operation) In the molding die having the above-described configuration, since the tip end surface of the core is exposed at the injection gate opening in the deburring process of the injection gate, it is necessary to remove the flash remaining on the injection gate. The tip of is exposed and the through hole of the molded product is completely opened automatically.

(Example) Below, this invention is demonstrated based on the Example shown in figure. First
The figure shows a mold according to a first embodiment of the present invention. Also in this embodiment, it is assumed that a molded product 105 having a through hole 106 in the center is molded as in the conventional example shown in FIGS. 8 and 9.

This molding die is composed of an upper die 1 and a lower die 2 and is provided at the upper end of the upper die 1 and is a chamber 3 for storing a molding material.
A piston 4 is inserted in the. Then, the fluidized molding material in the chamber 3 is injected and filled by the piston 4 from the injection gate provided in the upper mold 1 into the cavity 5 formed between the mating surfaces of the upper mold 1 and the lower mold 2. There is.

The lower mold 2 is provided with a core 6 protruding into the cavity 5. The core 6 is erected upright through the center of the cavity 5, and its front end surface 5a is in the mold closed state.
Has reached.

Further, a finishing injection gate 7 for injecting a molding material into the cavity 5 is formed at a portion corresponding to the core tip surface 6a of the upper mold 1. A main filling injection gate 8 is provided at a position separated from the finishing injection gate 7 by a predetermined distance.

In the molding die having the above configuration, when the upper die 1 and the lower die 2 are closed, the tip surface 6a of the core 6 closes the opening of the finishing injection gate 7, and the edge portion of the tip surface 6a is closed. It is in contact with the opening edge of the finishing injection gate 7. And piston 4
The molding material in the chamber 3 is pressed by and is injected into the cavity 5 from the main filling injection gate 8 to fill the molding material in the cavity 5.

When the injection gates 7 and 8 are deburred after vulcanization, as shown in FIG. 2, since the core tip surface 6a is exposed in the opening of the finishing injection gate 7, the finishing injection gate 7 When the flash 9 is removed, the core tip surface 6a is exposed, and when the mold 6 is opened and the core 6 is removed, the through hole 106 is completely opened in the molded product 105.

FIG. 3 shows a second embodiment of the present invention. The second embodiment is a molded product 20 as shown in FIGS.
The molded product 200 is a plug body formed of a rubber-like elastic body in a disk shape, and a reinforcing ring 201 is formed on its outer peripheral portion.
Are buried, and through holes 202, ... Are penetratingly formed at five central portions thereof. As shown in FIG. 6, a plurality of hole lips 203 are formed on the inner periphery of the through-hole 202 so as to project entirely inward in the middle thereof. This molded product 200 is the 7th
As shown in the figure, it is used by being press-fitted and fixed to the inner periphery of the hole 205 of the housing 204.

In the molding die 20, an upper die 21 and a cavity 23, which follows the shape of the molded article 200, is formed between the mating surfaces of the lower die 22,
A pin 24 as a core for molding the through hole 202 of the molded product 200 projects into the lower mold 22 into the cavity 23.

Then, the tip surface 24a of each pin 24 is placed in the upper mold 21 when the mold is closed.
The finishing injection gates 25 are provided at the portions corresponding to the tips of the pins 24 of the upper mold 21. In addition to the finishing injection gate 25, the upper mold 21 is provided with an injection gate 26 for main filling.

In the mold of the second embodiment, the reinforcing ring 201 is inserted into the cavity 23 and the mold is closed. In this mold closed state, the injection tip 25 for finishing is provided by the pin tip surface 24a.
Is blocked. When the cavity 23 is filled with the molding material from the main filling injection gate 26 and the flash in the finishing injection gate 24 after vulcanization and molding is removed, the pin tip surface 24a is exposed and the through hole of the molded product 200 is automatically formed. It will be possible to finish through 202.

(Effect of the Invention) The present invention has the above-described configuration and operation. Since the injection gate of the molding material is opened at the tip portion of the core corresponding to the through hole of the molded product, the injection gate is opened when the mold is opened. If the remaining burrs of the molding material are removed, the through holes of the molded product are automatically opened, and there is no need to deburr the through holes after taking out the molded product as in the conventional case. Therefore, the number of steps can be reduced, the productivity can be improved, and the cost can be reduced.

Further, it is possible to improve quality by eliminating the generation of unpenetrated products.

Further, there is little flash residue on the finished surface, and the effect of stabilizing the quality is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a molding die according to a first embodiment of the present invention,
FIG. 2 is a longitudinal sectional view of a main part showing a deburring state after vulcanization by the forming die of FIG. 1, FIG. 3 is a longitudinal sectional view of a forming die according to a second embodiment of the present invention, and FIG. FIG. 3 is a plan view of a molded product molded by the molding die of FIG. 3, FIG. 5 is a vertical sectional view of FIG. 4, FIG. 6 is an enlarged sectional view of a C part of the molded product of FIG. 5, and FIG. Fig. 4 is a vertical cross-sectional view showing the use state of the molded product, Fig. 8 is a plan view showing an example of a molded product having a through hole formed by a conventional molding die, and Fig. 9 is a vertical cross-sectional view of Fig. 8. , Tenth
The figure is a vertical sectional view of a conventional molding die. Explanation of symbols 1 ... upper mold, 2 ... lower mold 3 ... chamber, 4 ... piston 5 ... cavity 6 ... core, 6a ... tip surface 7 ... finishing injection gate 8 ... main filling Injection gate 9 …… Bur 20 …… Molding die, 21 …… Upper die 22 …… Lower die, 23 …… Cavity 24 …… Pin (core) 25 …… Finishing injection gate 26 …… Main filling injection Gate

Claims (1)

[Scope of utility model registration request] 1. A hollow cavity is formed between mating surfaces of an upper mold and a lower mold, and a core is provided in the lower mold so as to project into the cavity and reach a top end of the cavity. The molded product is formed by the core. A molding die having a through hole formed therein, wherein a casting gate closed by the core tip surface when the mold is closed is provided at a portion of the upper mold corresponding to the core tip.