JPH10166031A - Manufacture of metallic tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method free from any squeezing even in a thin-walled tube, unnecessary for cutting a tip, and capable of facilitating the handling of an extruded tube. SOLUTION: A metallic material 1 is fed to a passage 5 comprising an outer circumferential groove 3 provided on a rotary wheel 2 and a shoe block 4, and the metallic material fed to the inner end of the passage 5 is extruded as a metallic tube 10 from a gap between a die 7 arranged to the inner end of the passage 5 and a tip part 9 of a mandrel 8 where a tip part is faced to a bearing part 12 of the die 7. A through hole 13 to be communicated with the outside from the tip part 9 is provided in the mandrel 8, and the inside 11 of the metallic tube 10 to be extruded is kept at the atmospheric pressure through the through hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal tube using a rotating wheel type extruder.

[0002]

2. Description of the Related Art FIG. 3 shows an embodiment in which a metal tube is manufactured using a rotary wheel type extruder. The metal material (rough drawing line) 1 supplied to the outer circumferential groove 3 provided in the rotating wheel 2 is sent to the depth of the passage 5 by frictional force with the wheel 2, and the die 7 and the mandrel 8 arranged in the depth of the passage 5 The metal tube 10 is extruded from a gap between the end portion 9 and a predetermined metal tube 10.

In this case, the tip 11 of the metal tube 10 at the beginning of the extrusion is cut off halfway. This is an extruded metal tube 10
However, since the tip is easily deformed at a high temperature, the tip 11 is fused and closed, and the inside 12 of the tube is at a negative pressure with respect to the atmospheric pressure, the tube 10 is crushed if the extrusion is continued as it is.

[0004]

However, the above method has the following problems.

(1) For continuous extrusion, the extruded metal tube is wound up. However, if the length of the tube is long, the air flowing from the end to the inside of the tube becomes insufficient and the inside of the tube becomes negative pressure, and the end is cut. A decrease in crushing of the tube occurs as when not.
Therefore, a mechanism for reducing the winding tension as the extrusion progresses is required.

(2) Even if the end of the tube at the beginning of extrusion is cut to release the inside of the tube to atmospheric pressure, if the metal tube is crushed during material handling such as setting to a winder, it will be too early. Over time, the inside of the tube becomes negative pressure, and the treatment becomes complicated.

(3) Since the part released to the atmospheric pressure is only on the tip side of the metal pipe, negative pressure inside the pipe cannot be avoided in high-speed extrusion, and it is limited to a thick material.

Accordingly, an object of the present invention is to provide a manufacturing method which does not cause crushing or the like even in a thin-walled tube, does not require cutting of a tip, and can facilitate handling of an extruded metal tube. It is in.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is that, in the extrusion of a metal tube by a rotary wheel type extruder, a through hole is provided in a mandrel for forming the metal tube in cooperation with a die, and the through hole is used to extrude the metal tube. The inside of the metal tube is always kept at atmospheric pressure.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a manufacturing method according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the outline of a first embodiment of the method according to the present invention. The device comprises a rotating wheel 2 having an outer circumferential groove 3
And a shoe block 4 having a collecting chamber 6 connected to the outer peripheral groove 3 and in contact with the outer periphery of the rotating wheel 2 and having a collecting chamber 6 communicating with the passage 5, and a die arranged in the collecting chamber 6. 7 and a mandrel 8 which penetrates the shoe block 4 and has a front end 9 facing the bearing 13 of the die 7. The mandrel 8 has a predetermined thickness which penetrates the shaft core from the front end to the rear end. A through hole 14 is provided.

In the configuration of such an apparatus, the rotating wheel 2 is rotated at a predetermined speed, and a metal material 6, for example, an aluminum rough wire is continuously supplied to the groove 3 of the rotating wheel 2 so that the metal material 6 is rotated. 6 is sent to the interior of the passage 5 by the contact frictional force with the wheel 2 and reaches the collecting chamber 6,
From there, an aluminum tube 10 having, for example, an outer diameter of 7 mm and a wall thickness of about 0.1 mm is extruded from a gap between the die 7 and the tip 9 of the mandrel 8.

At the beginning of this extrusion, the distal end 11 of the metal tube 10 is closed. However, since the inside 12 of the tube communicates with the atmosphere through a through hole 14 provided in the mandrel 8, the metal tube 10 is formed. Even if the interior 12 has a negative pressure, the atmosphere flows through the through-holes 14 to prevent the metal tube 10 from being collapsed due to the negative pressure.

The extruded metal tube 10 is then cooled through a cooling means, for example, a cooling water bath (not shown) and wound up by a winder (not shown), but the inside 12 of the tube always passes through the mandrel 8. Since the tube 10 communicates with the atmosphere through the hole 14, even if the tube 10 is elongated or extruded at a high speed, the tube 10 is prevented from collapsing due to the negative pressure inside the tube 12.

If the interior 12 of the metal tube 10 to be extruded by supplying gas from the end of the through hole 14 at the initial stage of the extrusion is forcibly pressurized, a gap is formed at the tip 11 of the metal tube 10. Even so, when the cooling means as described above is employed, it is possible to prevent the cooling water from flowing through the gap.

FIG. 2 shows a second embodiment of the method according to the present invention, in which a metal tube having a plurality of spiral fins on its inner surface is manufactured. The same reference numerals are used.

In the case of this embodiment, a straight or spiral groove 15 is formed on the outer periphery of the mandrel tip 9 and the metal tube 10 is formed.
The metal tube 10 having a plurality of spiral fins on the inner surface is rotated by rotating the mandrel 8 at a predetermined speed via a power transmission mechanism by a driving source provided externally, for example, a motor 15 equipped with a speed reducer while performing extrusion. Although the mandrel 8 is manufactured, a through hole 14 is provided in the mandrel 8 from the tip side to the middle in order to prevent the inside 12 of the extruded tube from becoming negative pressure, and the end portion is formed between the shoe block 4 and the mandrel 8.
The inside of the metal tube 10 extruded by opening a hole in the space between the inside and the outside is communicated with the atmosphere.

By rotating the mandrel 8 in this manner, the bottom thickness is reduced to 0.3 as in the case of a metal tube having no fins on the inner surface.
The metal tube 10 having spiral fins on the inner surface of about 0.1 mm to 0.1 mm can be manufactured continuously.

In each of these forms, one wheel
The present invention is applied to a case where a plurality of outer circumferential grooves are provided on one wheel, and a plurality of outer circumferential grooves are provided on one wheel, and a plurality of passages are gathered and extruded. The present invention can also be applied to a type in which wheels are arranged symmetrically in the up and down direction, and passages are gathered and extruded in the middle.

[0020]

As is apparent from the above description, according to the present invention, since a mandrel is provided with a through hole and the inside of the extruded metal tube is made to communicate with the atmosphere and extruded, the extruded metal tube is provided. It is possible to always keep the inside of the inside at a pressure higher than the atmospheric pressure, it is not necessary to cut the tip, it is easy to handle, etc., and even if it is a thin aluminum tube with a wall thickness of about 0.1 to 0.3 mm, There is an advantage that a material without crushing can be extruded at a high speed.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a first embodiment of the method of the present invention.

FIG. 2 is an explanatory view schematically showing a second embodiment of the method of the present invention.

FIG. 3 is an explanatory diagram showing a conventional method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal material 2 rotating wheel 3 outer peripheral groove 4 shoe block 5 passage 6 collective chamber 7 die 8 mandrel 9 tip of mandrel 10 metal pipe 11 tip of metal pipe 12 inside metal pipe 13 die bearing part 14 through hole

Claims (3)

[Claims] 1. A die in which a metal material is supplied to a passage formed by an outer peripheral groove and a shoe block provided in a rotating wheel, and a metal material sent to a depth of the passage is disposed in a depth of the passage, and a tip and a die are formed by the die. In the method of extruding a metal tube from the front end of the mandrel facing the bearing portion, a through hole is provided in the mandrel from the front end to the outside, and the inside of the extruded metal tube is formed through the through hole. A method for producing a metal tube, characterized in that the pressure is maintained at atmospheric pressure through a pipe. 2. The method according to claim 1, wherein a mandrel provided with a plurality of grooves on the outer periphery of the tip is rotated by an external drive to form spiral fins on the inner surface of the extruded tube. 3. The method according to claim 1, wherein the inside of the tube is pressurized from the through hole of the mandrel at the beginning of the extrusion.