JPH0197612A - Method of forming two-layer rubber product having insert - Google Patents

Abstract

PURPOSE:To mold a quality product without flashes by a method including the steps of setting an insert on a support in a mold cavity, supplying a compressed, uncured rubber material, injecting an uncured rubber material by means of a plunger, and applying both materials to the insert. CONSTITUTION:An insert 9 is set on a support 8 in a cavity 7. A compressed material B of uncured rubber is supplied on the center of the support 8, while a molding material A of uncured rubber is charged in a pot 4. A lower mold 2 is raised to allow a plunger 5 to enter the pot 4 to charge the cavity 7 with the material A. When charged, the material A urges the insert 9 against the support 8. The molding material A flows toward the upper and outer peripheral portions of the insert 9, while the material B is compressed by a projection 3a and flows toward the lower and inner peripheral portions of the insert 9. Consequently, the insert 9 is coated with a double rubber layer of materials A and B, which is in conformity with the shape of the cavity 7.

Description

[Detailed Description of the Invention] Purpose of the Invention [Field of Industrial Application] The present invention relates to a method for molding a two-layer rubber product having an insert, and more specifically to a method for performing injection molding and compression molding almost simultaneously. be.

[Conventional technology]

Conventional molding of this type of two-layer rubber product is carried out by the steps shown in FIGS. 6-8. First, as shown in FIG. 6, the insert 24 is placed on the support part 23 formed in the cavity 22 of the lower mold 21, and the compressed material B made of unvulcanized rubber is accommodated in the cavity 22. On the other hand, the injection material A is put into the bot 26. Subsequently, as shown in FIG. 7, the lower mold 21 is raised to match the upper mold 25, and the compressed material B is pressed by the pressing protrusion 25a thereof.
At the same time, the pot 26 is brought into contact with the upper die 25, and the injection material A in the pot 26 is poured into the injection passage 26a formed in the pot 26 and the upper die 25 by the plunger 27.
, 25b into the cavity 22 to coat the injection material A and the compressed material B on the insert 24, and then vulcanize both materials by heating means (not shown) to form a 2M rubber product having the insert. is being molded.

[Problem that the invention seeks to solve]

However, in the above device, since a spring 28 is interposed between the plunger 27 and the bot 26 to urge them apart, the injection material A does not enter the cavity 22 as shown in FIG. Before being injected, the upper mold 2
The compressed material B is compressed by the pressing protrusion 25a of No. 5 and flows toward the bottom and inside of the insert 24, and the pressure lifts the insert 24 to create a gap between the insert 24 and the support part 23, and this gap Compressed material B enters the mold and remains as flakes after molding, which necessitates a flaking process.This also raises the problem of high manufacturing costs, especially when expensive rubber materials are used. .

Furthermore, if a large amount of the compressed material B enters between the insert 24 and the support portion 23, there is a problem that the insert 24 may become misaligned, resulting in a defective product.

This invention was made to solve the above-mentioned problems, and its purpose is to not only eliminate the need for a deburring process, but also to prevent the insert from becoming misaligned, and to improve the quality of the product. 2 with inserts that can
The present invention provides a method for forming layered rubber products.

Structure of the Invention [Means for Solving the Problems] In order to achieve the above object, the present invention sets an insert in a support formed in a cavity of a mold, and accommodates a compressed material made of unvulcanized rubber. Then, the injection material made of unvulcanized rubber housed in the bot is injected into the cavity using a plunger, and while pressing the insert toward the support part, the compressed material is compressed, and the injection material is injected into the insert. A structure is adopted in which a compressed material and a compressed material are applied.

[Action and effect]

According to this invention, before the compressed material is compressed and starts to flow, the insert is pressed by the injection material toward the support portion, so that the insert is not lifted up by the flowing compressed material, and the insert and the support portion are There is no gap between the two. Therefore, it is possible to prevent the compressed material from entering between the support portion and the insert, thereby preventing the occurrence of flakes, and also to prevent the insert from shifting, thereby improving the quality of the product.

〔Example〕

Hereinafter, a first embodiment of a molding method embodying this invention will be described.
This will be explained based on Figures 5 to 5.

First, the configuration of the molding apparatus will be described. A mold 1 includes a lower mold 2 that is raised and lowered by a lifting mechanism (not shown) and an upper mold 3 that is positioned above the lower mold 2. A bot 4 for charging injection material A and a plunger 5 fixed to a mounting frame (not shown) are arranged above the upper mold 3, and a force is applied between the bot 4 and the plunger 5 in a direction to separate them. A spring 6 is interposed for this purpose.

A ring-shaped insert 9 is placed in the cavity 7 provided in the lower mold 2. Ring-shaped support part 8 for placing
is formed, and a gasket 10 for maintaining airtightness during mold matching with the upper mold 3 is disposed to surround the cavity 7.

A heat insulating plate 11 is attached to the lower surface of the bot 4, and a plurality of injection passages 4a for supplying the injection material A are formed in the bot 4. Further, a gasket 12 for maintaining airtightness between the bot 4 and the upper mold 3 during injection is arranged so as to surround the heat insulating plate 11.

A pressing protrusion 3a for compressing the compressed material B disposed at a predetermined position in the cavity 7 of the lower mold 2 is formed in the center of the lower surface of the upper mold 3, and corresponds to the support part 8, and an injection passage 3b that can communicate with the injection passage 4a.
is formed.

Further, a laminated disc spring 13 is disposed at each corner of the lower mold 2, and as shown in FIG. The pressing protrusion 3a is strong enough not to compress the compressed material B until the injection of the compressed material B is started.

Now, in order to mold a two-layer rubber product using the molding apparatus configured as described above, first, as shown in FIG.
, the upper die 3, the bot 4, and the plunger 5 are held apart from each other, the insert 9 is placed on the support part 8 in the cavity 7, and a compressed material made of unvulcanized rubber is placed in the center of the support part 8. B is housed in the bot 4, while an injection material A made of unvulcanized rubber is put into the bot 4.

Next, as shown in FIG. 2, the lower mold 2 is raised and the chambers R1 and R2 are evacuated with the gaskets 10 and 12 in contact with the upper mold 3. After this, when the lower mold 2 is further raised as shown in FIG.
The injection of the injection material A into the cavity 7 is started through the injection valve.

At this time, due to the biasing force of the disc spring 13, the pressing protrusion 3a of the upper die 3 is not compressing the compressed material B, and the insert 9 is pressed toward the support portion 8 by the injected injection material A.

When the lower mold 2 is subsequently raised, the injection material A flows toward the top and outer circumference of the insert 9, as shown in FIG.
is compressed and flows toward the lower part and inner circumference of the insert 9, allowing the insert 9 to be coated with a 2Wi rubber layer of injection material A and compressed material B that follows the shape of the cavity 7, and then, When both materials A and B are vulcanized by heating means (not shown), a two-layer rubber product having an insert is completed.

Now, in this embodiment, before the compressed material B is compressed and begins to flow, the insert 9 is inserted into the support part 8 by the injection material A.
Since it is pressed to the side, the fluid compressed material B
Therefore, the insert 9 is not lifted up, and no gap is created between the insert 9 and the support part 8. Therefore,
It is possible to prevent the compressed material B from entering between the support part 8 and the insert 9, thereby preventing the occurrence of flakes, and also to eliminate the waste of the compressed material B, which makes it possible to use particularly expensive rubber materials. When used, increases in manufacturing costs can be suppressed. Moreover, the positional shift of the insert 9 can be prevented, and the quality of the product can be improved.

[Brief explanation of the drawing]

1 to 5 show an embodiment of a molding method embodying the present invention, in which FIG. 1 is a cross-sectional view showing the material charging state, FIG. 2 is a cross-sectional view at the start of mold clamping, and FIG. 3 is a cross-sectional view during mold clamping, FIG. 4 is a cross-sectional view when mold clamping is completed, and FIG. 5 is a partially enlarged cross-sectional view of FIG. 4. . 6 to 8 show the conventional molding method.
The figure is a cross-sectional view showing the material charging state, FIG. 7 is a cross-sectional view in the middle of mold clamping, and FIG. 8 is a partially enlarged cross-sectional view of FIG. 7. In the figure, 1 is a mold, 4 is a bot, 5 is a plunger, 7 is a cavity, 8 is a support part, 9 is an insert, A is an injection material, and B is a compression material. Patent applicant Toyoda Gosei Co., Ltd. Agent
Patent Attorney On 1) Hironobu Figure 3 Figure 4 Δ

Claims (1)

[Claims] 1 Set the insert (9) in the support part (8) formed in the cavity (7) of the mold (1), contain the compressed material (B) made of unvulcanized rubber, and place the pot (4)
The injection material (A) made of unvulcanized rubber housed inside is injected into the cavity (7) using a plunger (5), and while pressing the insert (9) toward the support part (8), A method for molding a two-layer rubber product with an insert, characterized in that the compressed material (B) is compressed and the insert (9) is coated with the injection material (A) and the compressed material (B).