JPS6219242B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to an extrusion molding apparatus.

PRIOR ART A pipe material in which a pipe or a plurality of hollow parts are extended in parallel in the longitudinal direction in order to flow a fluid such as a liquid or gas at a desired temperature and pressure is used, for example, in a water heater, It is widely used in radiators or heat exchangers for hair dryers, air conditioners, pots, and other equipment. When processing these pipes and pipe materials, if the inner diameter of the hollow portion serving as the fluid path is large, they can be easily molded using an extruder equipped with a normal mandrel. However, if the inner diameter is small, the diameter of the mandrel for forming the hollow part must also be changed.
Due to the small diameter, this small diameter mandrel cannot withstand the extrusion pressure and breaks during extrusion. For this reason, when forming a pipe or pipe material with a small diameter hollow part, it is necessary to extrude the pipe or pipe material with an inner diameter larger than the specified inner diameter and that can be extruded using a normal mandrel. A pipe or pipe material having an inner diameter larger than this predetermined value is subjected to post-processing such as drawing to have a predetermined inner diameter. That is, it requires two steps: extrusion and drawing. For this reason, at least two molding machines, such as an extruder and a drawing machine, are required to mold pipes or pipe materials with small inner diameters. This is extremely uneconomical and is a major cause of increasing product prices.
An example of this can be found in, for example, Japanese Patent Publication No. 10700/1970.

Problems to be Solved by the Present Invention The present invention aims to solve the problems of the conventional example as described above.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has the following features:
a first forming hole after the welding chamber;
A contiguous configuration with a passage between the tapered surface and the mandrel and a second forming hole is adopted.

Effect: By employing the above-mentioned means, the metal flow between the first and second forming holes changes uniformly and does not adversely affect the billet. Therefore, there is no dimensional error between the start and end of extrusion of one billet.

EXAMPLE Referring to FIG. A dummy block 2 and a stem 3 are arranged in a conventional manner in a container 1 of the extruder, and although not shown, the stem 3 is interlocked with a known pressurizer. At the front end of container 1,
An extrusion die consisting of upper and lower dies 4 and 5 is arranged. The upper die 4 has a porthole 6 and a mandrel 7 in the center thereof.
Further, a welding chamber A is formed between the upper and lower dies 4 and 5, and the metal from the porthole 6 is welded together within the chamber A. The mandrel 7 is machined to a size that can withstand pressure during extrusion molding, and is machined to have a larger inner diameter than the desired extruded shape. A lower die 5 is disposed in contact with the upper die 4, or the lower die 5 has a tapered surface in its center to reduce the outer dimensions of the extruded section. The minimum diameter of the tapered surface 8 is matched to the outer diameter required for the final extruded product. Further, its maximum diameter is selected to be larger than the outer diameter of the mandrel 7, and a passage is formed between the upper wall 10 of the lower die 5, the tip of the mandrel 7, and the maximum diameter portion of the tapered surface 8.

A guide 12 extending into the hollow part 9 of the lower die 5 is fixed to the mandrel 7. This guide 1
2 is formed with a tapered surface 13 whose diameter decreases toward the tip, and the minimum diameter portion of the tapered surface 8 of the lower mold die 5 and the tapered surface 1 of the guide 12 are formed.
3 determines the wall thickness of the desired product, and the minimum diameter portion of the tapered surface 13 of the guide 12 determines the inner diameter of the hollow portion of the desired product. During ironing with the lower die 5, the guide 12 supports the hollow part of the extruded product, so that the shape of the hollow part can be accurately obtained. Moreover, the guide 12 is a mandrel 7 with a large diameter.
It can withstand extrusion pressure sufficiently. The guide 12 is screwed onto the mandrel 7, for example.

In the illustrated example, the mandrel 7 and the lower die 5
The gap B between the welding chamber A and the wall surface becomes a first forming hole for preforming the material in the welding chamber A into a section having a larger cross-sectional shape than the final cross-sectional shape. The gap C between the tip of the guide 12 and the tapered surface 8 is the first
The preformed material is formed into the final shape in the forming hole B.

The die shown in the first figure is suitable for the production of hollow pipes, or the die shown in figures 2 and 3 are suitable for manufacturing hollow pipes.
It is suitable for manufacturing a pipe material 15 in which a plurality of hollow portions 14 are arranged in parallel. In the example shown in FIG. 2, the lower die 5
A hollow portion 16 having a tapered surface is formed in the hollow portion 16 . The inner diameter of this hollow portion 16 is gradually reduced, and becomes the outer diameter of the pipe material 15 at the tip. A guide 17 is disposed within the hollow portion 16 for forming the hollow portion 14, which becomes a plurality of parallel fluid passages. The guide 17 has a tapered surface 18 whose diameter gradually decreases. Guide 17
can be fixed to the mandrel 19. The minimum diameter portion of the guide 17 determines the inner diameter of the plurality of hollow portions 14 of the pipe material 15. A solid portion of the pipe material 15 is formed between the guides 17 and between the guide 17 and the tapered surface 16 of the lower die 5.

The example shown in FIG. 3 differs in that it is a spider type, whereas the example shown in FIG. 2 is a porthole type, but is substantially extruded in the same manner as the example shown in FIG.

Effects With the present invention, pipes and pipe materials with small hollow parts, which conventionally required two processes of extrusion and drawing, can be directly manufactured by an extrusion process, which simplifies the process and reduces product prices. I can do it. In addition, the lower die and guide have a simple shape and are easy to manufacture, and can be attached to a conventional extruder, so they can be used without modifying the extruder. Enables extrusion of pipes and pipe materials.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a cross-sectional view showing another example, FIG. 3 is a cross-sectional view showing another example, and FIG. 4 is a cross-sectional view of a pipe material. In the figure: 1...container, 3...stem, 4...upper die, 5...lower die, 7, 19...mandrel,
8, 16...Tapered surface, 12, 17...Id.

Claims (1)

[Scope of Claims] 1. In an extrusion molding apparatus equipped with an extrusion die having an upper die and a lower die, the upper die of the extrusion die has a porthole for diverting the billet, and the diverted metal is welded. forming a welding chamber between the upper and lower molds,
A first forming hole for preforming the material in the welding chamber into a cross-sectional shape larger than the final cross-sectional shape is provided by the mandrel of the upper die and the wall surface of the lower die; The mold die has a second molding hole continuous with the first molding hole on the rear side of the first molding hole, and the preformed shape is given a final shape by the second molding hole,
A passage is provided in the lower die between the forming hole and the second forming hole, the inner circumferential surface of which is a tapered surface that gradually decreases in diameter, and the mandrel extends into the passage. 1. An extrusion molding device, characterized in that it has a portion that is 2. The extrusion molding apparatus according to claim 1, wherein the upper die has a plurality of mandrels and is configured to mold a pipe material having a plurality of hollow parts.