JPH0382526A - Preventive technique of difference in level of hollow molding - Google Patents

Abstract

PURPOSE:To constitute the title technique so that a difference in level is not generated on a connecting part between an extrusion molded part and pattern molded part, by a method wherein at the time of molding of the pattern molded part by adjoining to an extrusion hollow molded product along with vulcanization by fitting a semiproduct of the extrusion hollow molded product into a mold, a core comprised by forming a spiral groove in the outside of the core to be inserted into a hollow part of the semiproduct is used. CONSTITUTION:At the time of molding of pattern molded parts 3a, 3b along with vulcanization by fitting semiproducts 1a, 1b of extrusion molded products into molds 6a, 6b, cores 4a, 4b obtained by forming spiral grooves 5a, 5b in the outside of cores to be inserted into hollow parts 2a, 2b of the semiproduct 1a, 1b are used. Repelling force Q from the inside opposing to clamping pressure P from the outside is unified and mitigated all over the surface by inserting the cores 4a, 4b having the spiral grooves 5a, 5b in the outside into the hollow parts 2a, 2b. Therefore, thicknesses of the semiproducts 1a, 1b can be absorbed between the sprial grooves 5a, 5b of the cores 4a, 4b and it is hard to generate a difference in level on a connecting surface M-M.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention involves fitting a semi-finished product of an extrusion hollow molded product into a mold,
The present invention relates to a construction method for preventing surface differences that occur on connecting surfaces when molded parts are molded adjacent to each other and vulcanized.

<Prior Art> There is a rubber weather strip for automobiles in which the sealing portion is hollow. Weatherstrips are string-like and have approximately the same cross-sectional shape, so the straight parts and large circular arc parts are made by extrusion, but the parts that connect two extruded weatherstrips and the corners of car entrances are made by molding. Made with. However, there is a problem in that a surface difference occurs at the connection point between the extrusion molded part and the die molded part.

Regarding the conventional method, Fig. 1 to Fig. 3 and Fig. 5 to Fig. 7
To explain with reference to FIGS. 9 and 9, semi-finished products 1a and 1b of extruded hollow molded products are fitted into molds 5a and 5b, and molded parts 3a and 3b are formed between them. 2a2b, the center core 7a shown in FIGS. 5 and 9;
After inserting and arranging the core 7b and performing heat molding and vulcanization, the core 4a
, 4b is removed.

<Problems to be Solved by the Invention> In the conventional molding method described above, during vulcanization, mold clamping pressure P is applied from the outside of the extruded products 1a, lb, and mold clamping pressure is applied from the inside of the hollow parts 2a, 2b. A repulsive force Q equal to P is applied to the cores 4a and 4b.

The repulsive force Q of the cores 4a, 4b is the extruded portion 1a, l.
There is a problem in that a surface difference appears on the connecting surface M-M between the molded parts 3a and 3b, and the appearance is impaired.

An object of the present invention is to provide a method for preventing surface differences in blow molded products that solves the above problems.

<Means for solving the problem> Description will be made with reference to FIGS. 1 to 4 and FIGS. 6 to 8.

In order to achieve the above object, the method for preventing surface difference in a hollow molded product according to the present invention involves fitting semifinished products 1a and lb of extruded hollow molded products into molds 5a and 5b, and molding molded parts 3a and 3b. At the same time, during vulcanization, the core 4 is inserted into the hollow parts 'la, 'lb of the semi-finished products 1a, lb, and has spiral grooves 5a, 5b formed on the outer surface thereof as shown in FIGS. 4 and 8.
a and 4b are used.

<Effect> A core 4a with spiral grooves 5a and 5b formed on its outer surface.

4b into the hollow parts 2a and 2b of the semi-finished products 1a and lb, the repulsive force Q from the inside that opposes the mold clamping pressure P from the outside is equalized and relaxed over the entire surface, and the semi-finished products 1a, lb of wall thickness can be absorbed between the spiral grooves 5b, 5b, making it difficult for surface differences to occur on the connecting surfaces M-M, and also preventing shrinkage due to the injection pressure of the molded parts 3a, 3b.

<Example> Ia and lb are semi-finished products of extrusion vulcanization hollow molded products, respectively;
2a and 2b are the respective hollow parts, and 4a and 4b in FIGS. 4 and 8 are the cores inserted into the respective hollow parts 2a and 2b during vulcanization, and a single screw thread continuous to the outer surface. The spiral grooves 5a and 5b are formed. In addition, in the figure, 11
1 is a sponge rubber part, 12 is a solid rubber part, and 13 is an insert metal.

Next, the effect will be explained. Spiral grooves 5a, 5b on the outer surface
The semi-finished product 1a includes cores 4a and 4b having the following properties.

By inserting the mold into the hollow parts 'la and 2b of 1b, the repulsive force Q from the inside that opposes the mold clamping pressure P from the outside is equalized and relaxed over the entire surface, and the thickness of the semi-finished products 1a and 1b is reduced. Spiral grooves 5a in the cores 4a, 4b.

5b, it is difficult to cause a surface difference between the connecting surfaces M-M, and furthermore, it is possible to prevent the molding parts 3a and 3b from shrinking due to the injection pressure.

This method is particularly applicable to hollow molded products made of solid sponge metal, as shown in FIGS.
It is also effective when the cross section of b is circular, and the center core 3
Processing cost of b is also low and can be easily implemented.

<Effects of the Invention> Since the present invention is configured as explained above, the semi-finished products 1a and lb of continuous extrusion hollow molded products are placed in the molds 6a and 6.
b, it is possible to easily prevent the difference in surface that occurs on the connecting surface M-M when the molded part is molded into the adjacent part and vulcanized, and the appearance is improved.

[Brief explanation of drawings]

Figures 1 to 4 are for explaining the first embodiment of the present invention; Figure 1 is a plan view of the manufacturing process, Figure 2 is a side view of the automobile, and Figure 3 is a sectional view of the product. , FIG. 4 is a perspective view of the center core, and FIG. 5 is a view corresponding to FIG. 4 of a conventional product. Figures 6 to 8 are for explaining the second embodiment of the present invention. Figure 6 is a plan view of the manufacturing process, Figure 7 is a perspective view of the product, and Figure 8 is a view of the center core. The perspective view, FIG. 9, is a view corresponding to FIG. 8 of the conventional product. 1a, 1b Semi-finished products 2a, 2b Hollow parts 3a, 3b Mold forming parts 4a, 4b Cores 5a, 5b! ll'll grooves 5a, 5b Molds 7a, 7b Core 11 Sponge rubber part 12 Solid rubber part 13 Insert metal M Connection surface P Mold clamping pressure Q Internal force patent Applicant Nishikawa Rubber Industries Co., Ltd. Representative Patent attorney Furukawa 1) Tsuyoshi Kei Figure 1 Figure 4 Negative Figure 5 Figure 6 Figure 7 Figure 8 h Figure 9

Claims (1)

[Claims] [1] The semi-finished products (1a, 1b) of the extrusion hollow molded product are fitted into the molds (6a, 6b), and the molded parts (3a, 3b) are molded adjacently and when vulcanizing, the semi-finished products (1a, 1b) are Product (1
The core (4) is inserted into the hollow portion (2a, 2b) of (a, 1b) and has spiral grooves (5a, 5b) formed on the outer surface of the core.
A method for preventing surface differences in hollow molded products, characterized by using a, 4b).