JPS60161118A - Manufacture of rubber or resin tubular product - Google Patents

Abstract

PURPOSE:To mold a resin tubular product with no flash developed on the inside surface of a pipe by a method wherein a flexible annular sealing member is tightly fitted on the butting portion of a plurality of cores, all of which are arranged within a mold. CONSTITUTION:A gap of a butting line 5 of cores 1 and 1 is sealed with a sealing member 3. The resultant sealed cores 1 and 1 are put in a mold (not shown) and resin material 4 is poured in the mold. Because the gap of the butting line 5 of the cores 1 and 1 is sealed with the sealing member 3, no resin material 4a penetrates into the gap. The resin material 4a covering the outer periphery of the core 1 has favorable bonding power to the sealing member 3, resulting in strongly bonding the sealing member 3 and the resin material 4a into an integral structure. A complete straight pipe 4 is obtained by drawing the cores 1 and 1 out, after the solidification of the resin material 4a. No flash develops at all on the inside surface of the pipe, because no resin material penetrates into the butting line of the cores 1 and 1.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a rubber or resin tubular article.

Conventionally, straight pipes made of rubber or resin are made by connecting a plurality of cores t1) [1) straight together as shown in Fig. 6, and passing this through a rad die (not shown) to the cross of an extrusion molding machine. It is manufactured by a step of covering the outer periphery of the core with material (4a), and a step of removing the core (1) once the material (4a) has solidified.

However, it is unavoidable that a slight gap will be created at the butt part of the core, and a material with good fluidity will enter the gap, resulting in a burr IJ (41i). There was a problem with resistance to the fluid passing through it.

Moreover, the above problem is not limited to straight pipes manufactured by extrusion molding, but also when multiple cores are butted at right angles in a mold and the cavity formed between the core and the mold is filled with material. This also happened when manufacturing bent pipes.

〔the purpose〕

The object of the present invention is to prevent material from entering the gap between the abutting portions of the cores, and to produce a tubular product that does not have any cracks on its inner surface.

〔composition〕

The basic process of butting together multiple cores, covering the outer periphery of the cores with liquid rubber or resin material, and removing the cores after the material hardens to form a tubular object is the same as before, but Before covering the core with material, make sure it has good adhesion to the material of the tube (,
It is characterized in that a sealing member formed of a material with low adhesiveness to the core is tightly fitted to the outer periphery of the abutting part of the core so that the entire length of the crease line of the core is hidden.

[Function and Effect J: The abutting portion of the core is tightly covered with a sealing member, which reliably prevents material from entering through the gap between the butt lines.
Further, since the material and the sealing material have good adhesive properties, they become an integral part, and the sealing member becomes a part of the wall of the tubular object.

Therefore, it is possible to leave only the core inside the tube while leaving the sealing member inside the tube, and no cracks are generated on the inner surface of the tube.

The present invention will be specifically described below based on embodiments shown in the drawings.

Figure 1 shows the core (1) (1) for manufacturing straight pipe (4).
, both cores (11 (11 is removably connected straight) by engagement means (2) such as screw engagement.

There is a butt line (5) on the outer periphery of the butt part of the center core (1)
) with a flexible ring-shaped seal member (3
) is fitted closely to the core +11 +1+.

The sealing member (3) is preferably made of the same rubber or resin material as the material of the straight pipe (4) to be formed, which has good adhesion to the rubber or reciprocal material (4a) of the straight pipe (4) to be formed. has been done.

In the example, the material of the straight pipe is silicone rubber and the sealing member (
3) is also made of silicone rubber.

However, as described above, the core +1) LL) with the sealing member (3) fitted in the butt part was inserted into the crosshead of the extrusion molding machine (
The material (not shown) is passed continuously around the outer periphery of the core (1).
Cover with 4a).

At this time, the gap between the butt lines (5) of the core (1) tl) is sealed by the sealing member (3), so the material (4a) does not enter. In addition, the seal member (3
), since the material (4a) covering the outer periphery of the core (1) has good adhesive strength, the sealing member (3) and the material (4a)
It is strongly connected and becomes a whole.

After the material hardens, if you pull out the core, the straight pipe (4) is completed.As mentioned above, there is no material intrusion from the butt line of the core, so there is no paris on the inner surface of the pipe. , the sealing member (3) remains in the tube (4) as part of the wall of the tube and does not come out about the core (1).

Figure 3 shows a three-pronged tubular joint (6) manufactured according to the present invention.
It shows.

"The second joint (6) has three cylindrical parts f61) +62+ +
63+ butted against each other at right angles.

The above joint has three central cores tl) (1) as shown in Figure 3.
tl) are butted against each other at right angles in a mold (not shown), and the material is pressurized and filled into the cavity formed between the mold and the core (11). The butt line (5) of the core (1) (11(1)) is covered with a sealing member (3) with good adhesiveness in close contact with the three-pronged joint (6) to be formed in the same manner as described above. 17-- As shown in Figure 3, the sealing member (3) is made of material with good elasticity and is formed into a short cylindrical shape, and a cut (5) is made approximately halfway around the circumference in the center of the material. As shown in FIG. 5, each opening (33) (33i (3
1a) Figure 3 As shown in Figure 1, the three cores +1) (-
1) Pass through +1) and seal the abutting portion of core +1) (11 (1). If the sealing member (3) has good elasticity, it is possible to seal in this way.

Of course, the present invention can be applied to the manufacture of L-shaped or T-shaped tubular products, in addition to the above-mentioned straight pipes and three-pronged joints made by butting two cores at right angles. .

[Brief explanation of the drawing]

Figure 1 is a sectional view of the butting part of the core when manufacturing a straight pipe, Figure 2 is a slope view of the three-pronged joint, and Figure 3 is the butt of the core for making the same joint as above. Slope view showing 4th
The figure is a sectional view of another embodiment of the sealing member, FIG. 5 is a perspective view of the same sealing member in an open state, and FIG. 6 is a sectional view of a conventional example. (1)...Inner core (3)...Seal member applicant
Kinjo Gome Co., Ltd.

Claims (1)

[Claims] ■ A plurality of cores are butted against each other, and a sealing member made of a material that has good adhesion to the material of the tubular object to be molded and has little adhesion to the core is pressed against the cores. Fit the core closely to the outer periphery of the mating part so that the entire length of the mating wire is hidden, cover the outer periphery of the core with liquid rubber or resin material, and after the material hardens, remove the core to form a tubular object. A method for manufacturing rubber or resin tubular products. (2) The method for manufacturing a rubber or resin tubular article according to claim 1, wherein the two cores are butted straight against each other. (2) The method for producing a rubber or resin tubular article according to claim 1, wherein the two cores (1) (tl) are butted against each other at right angles. (2) The method for manufacturing a rubber or resin tubular article according to claim 1, wherein the three cores are butted against each other at right angles.