JPH0118335Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vertically split mold used for molding cloth-filled rubber products, and aims to reduce costs by improving workability and saving surplus rubber.

For example, in order to mold a rubber product a containing cloth b as shown in FIG.
1. A split mold 1 consisting of a lower mold 12 is used. 2 is a molding cavity, 3 is a molding part of bead C, and 6 is a mold matching part.

When the upper mold 11 is opened by the press molding machine used, a release agent is applied to the upper mold 11, unvulcanized rubber is placed in the lower mold 12, and the rubber is molded into a semi-vulcanized state. Third
As shown in the figure, the upper mold 11 is opened, the reinforcing base fabric b is set on the semi-vulcanized molded product on the lower mold, and the mold is closed and molded and vulcanized together with the base fabric 4. After molding, remove the burrs around it and punch out the center hole d to obtain the product.

When the semi-vulcanized mold is opened, substantially trapezoidal rubber grooves 4 and 5 are formed in order to leave the rubber molded product in the lower mold 12, so that the semi-vulcanized molded product does not easily come off from the lower mold. be.

Even if the mold is configured as described above, the semi-vulcanized product is fixed to the lower mold 12 in the trapezoidal rubber grooves 4 and 5, but it adheres to the upper mold 11 on the surface of the cavity 2 and is not completely attached to the lower mold 11. It was difficult to release the mold so that it remained, resulting in poor workability. Further, in order to provide the rubber grooves 4 and 5, extra rubber is required, which also has the drawback of increasing costs.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, and after molding unvulcanized rubber into a semi-vulcanized state in the cavity 2 between the upper mold 11 and the lower mold 12, the mold is opened and the semi-vulcanized rubber is molded. In a mold for molding cloth-filled rubber products, in which reinforcing base fabric b is set on top of the molded product, the mold is closed, and the mold is vulcanized integrally with the base fabric, when the semi-vulcanized mold is opened, the semi-vulcanized molding is performed. The surface of the cavity 22 of the mold 11 on the side from which the product is released is formed into a rough surface 11a to the extent that it does not have a biting force against the molded product, and the surface of the cavity 2 of the mold 12 on the side where the semi-vulcanized molded product is left. 12a is formed on a surface that has greater adhesion to the molded product than the rough surface 11a.

Although FIG. 4 shows an embodiment in which the upper mold 11 is on the mold release side and the lower mold 12 is on the side where the molded product is left, it is also possible to set the base fabric b on the lower mold 12 in an upside-down manner.

The above-mentioned rough surface 11a is a rough surface with a not-so-acute cross-sectional shape, and the other surface 12a is, for example, given a mirror finish with a large suction force. The rough surface 11a is
It was found that formation on a rough surface of ~10 μm is good.

Alternatively, the cavity surface of the lower mold may be formed into an acute rough surface to impart adhesion to the molded product by biting.

As a method for roughening the surface, glass shot blasting is appropriate since sand shot blasting significantly abrases the surface of the mold. In order to form a rough surface with an acute angle, a sharp medium in the shape of a glass shot is used.

In this invention, as mentioned above, one surface forming the upper-lower split mold cavity is finished with a rough surface consisting of minute concavities and convexities, so air stays in the concavities and expands with heating and pressure during molding. The rubber product a is prevented from adhering to the surface 11a. Since the cavity surface 12a on the opposite side is finished with a mirror surface or a rough surface with an acute angle in cross-section, the rubber product will stick to the mirror surface or bite into the acute angle portion and adhere, and will remain on the surface 12a side. .

Therefore, when opening the mold to set the base fabric in the above process, the semi-vulcanized molded product is easily released from the rough side of the cavity, improving workability. In addition, the conventional trapezoidal rubber groove for biting can be omitted, and the rubber material is also omitted, which reduces material costs, especially when using expensive rubber materials such as silicone rubber, and reduces the cost of molded products. It has great economical effects, such as omitting the deburring process.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a cloth-filled rubber product, FIGS. 2 and 3 are sectional views of the left half of a conventional mold, and FIG. 4 is a sectional view of the right half of the mold of the present invention. 1 is a split mold, 11 is an upper mold, 12 is a lower mold, 2 is a cavity part, 3 is a bead part, 4 and 5 are trapezoidal rubber grooves,
6 is a mold matching part, and 11a is a rough surface.

Claims (1)

[Scope of Claim for Utility Model Registration] After molding unvulcanized rubber into a semi-vulcanized state in the cavity between the upper and lower molds, the mold is opened and a reinforcing base fabric is set on top of the semi-vulcanized molded product. , in a mold for molding cloth-filled rubber products that is vulcanized integrally with the base fabric after closing the mold, when opening the semi-vulcanized mold, the side of the cavity of the mold on the side from which the semi-vulcanized product is to be released is The surface is formed so rough that it does not have any biting force against the molded product, and the cavity surface of the mold on the side where the semi-vulcanized molded product remains is formed to have a greater adhesion force to the molded product than the rough surface. A mold for molding cloth-filled rubber products.