JPH06210342A - Tool and method for extruding hollow product - Google Patents

Abstract

PURPOSE:To enable secure removal of a discard and to improve the life of a tool without damaging the tong part of a die when the discard is cut off. CONSTITUTION:An extruding tool 3 is constituted of a die 4 having the tong part 10 on the inner peripheral surface and regulating the shape of the outside surface of an extruded shape member 8 and a mandrel 5 regulating the shape of the inside surface of the extruded shape member 3. Since the end part on the side of the die 4 is made in the shape of a stepwise shaft, the mandrel 5 is inserted into the die 4 at the time of an ordinary extrusion and has a small diameter part 5A regulating the inside shape of the extruded shape member 8 and a large diameter part 5B having the outer diameter nearly equal to the distance between the tips of the tong part 10 and inserted into the die 4 in the end of working.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion tool for a hot extruder for continuously extruding hollow products such as aluminum tubes and a method for extruding hollow products.

[0002]

2. Description of the Related Art Generally, for extrusion processing of hollow metal products such as aluminum, an extrusion tool consisting of a die for defining the outer surface shape of the product and a mandrel for defining the inner surface shape of the product is mounted in a container and a billet is added. It is done by pressing it out of the die. 5 to 7 are views showing a conventional extrusion tool and an extrusion processing procedure, wherein 1 is a container, 2 is a billet 2 made of aluminum or an aluminum alloy which is heated to a predetermined temperature and loaded in the container 1, and 3 is a die 4. And a mandrel 5, an extrusion tool, 6 is a loose dummy, and 7 is a stem. During extrusion, the loose dummy 6 is fixed to the container 1, the die 4 and the mandrel 5 are moved to the right, the billet 2 is pressed, and the desired hollow profile 8 is obtained by pushing out from the hole of the die 4. Yes (Figs. 5 and 6). After the extrusion is completed, the mandrel 5 is retracted, the die 4 is pulled out from the container 5, and the unpressed material attached to the die 4 (discard)
9 is knocked down by a discard shear (not shown),
Separate from the die 4 (Fig. 7).

[0003]

As described above, the discard 9 attached to the die 4 is extruded by a discard shear after the extrusion, but in that case,
In the die 4 integrally provided with the tongue portion 10 on the inner peripheral surface as shown in FIG. 8, in addition to the portion corresponding to the length l of the tongue portion 10, the tip of the tongue portion 10 and the outer peripheral surface of the mandrel 5 are formed. Since the discard 9 remains in the part 11 between them,
Greater force is required when knocking out discard 9,
Further, particularly when the tongue portion 10 is long and thin, there is a problem that the tongue portion 10 is easily damaged even by a small impact and the die life is short.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to ensure the discard without damaging the tongue portion of the die when the discard is cut. It is an object of the present invention to provide a hollow product extruding tool and a hollow product extruding method that can be removed and that can increase the tool life.

[0005]

To achieve the above object, the first invention comprises a die including a tongue portion for defining the outer surface shape of the extruded profile, and a mandrel for defining the inner surface shape of the extruded profile. , The mandrel has a die-side end portion formed in a stepped shaft shape, so that a small-diameter portion that is inserted into the die during normal extrusion processing and defines the inner surface shape of the extruded profile, and the tongue portion that is larger than the small-diameter portion. And a large-diameter portion which has an outer diameter substantially the same as the tip-to-tip distance and is inserted into the die at the end of extrusion processing. A second aspect of the invention is to extrude a billet using the hollow product extruding tool according to the first aspect of the invention, then advance a mandrel to extrude an unpressed material remaining in the die at its large diameter portion, and The mandrel is retracted and the discard is removed from the die.

[0006]

The large-diameter portion of the mandrel moves forward after extrusion and is inserted into the die to push out the discard between the tongue tips. Therefore, only the discard corresponding to the length of the tongue portion remains, which facilitates cutting and removal of the discard.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view showing an embodiment of a hollow product extruding tool according to the present invention, and FIG. 2 is a front view of a die. In the figure, the same components as those of the conventional tool shown in FIGS. 5 to 8 are designated by the same reference numerals, and the description thereof will be omitted. In these figures, in this embodiment, by forming the end portion of the mandrel 5 on the die 4 side in a stepped shaft shape,
A small-diameter portion 5A that defines the inner-diameter dimension D1 of the extruded profile 8 and a large-diameter portion that is provided coaxially with the small-diameter portion 5A and has a diameter D3 that is substantially the same as the tip-to-tip distance D2 of the tongue portion 10 of the die 4. 5B is provided, and the step surface 21 between the small diameter portion 5A and the large diameter portion 5B is chamfered at an angle of approximately 45 °.

The material of the mandrel 5 is hot tool steel, for example JIS G4404 (1983) SKD61.
Etc. are used. The diameter D1 of the small diameter portion 5A is 17.19 m.
m, the length L1 is about 35 mm, the diameter D3 of the large diameter portion 5B is 30.5 mm, and the length L2 is about 30 mm.

The die 4 has a plurality of (for example, six) tongue portions 10 projecting from the inner peripheral surface thereof at equal intervals in the circumferential direction. The inner diameter D of the die 4 is 59.77 mm, the tongs 1
The length l of 0 is 13.99 mm and the maximum width W is 6.56 m
m, and the distance D2 between the tips is about 31.79 mm, which constitutes an extrusion tool for continuously extruding the hollow shape member 8 together with the mandrel 5. The die 4 is also made of hot work tool steel such as SKD61 like the mandrel 5.

Next, the extrusion processing of the hollow frame member 8 will be described with reference to FIGS. During normal extrusion, the die 4 and the mandrel 5 are moved to the right while the small diameter portion 5A of the mandrel 5 is inserted into the die 4 with a required size as shown in FIG. 1 to add the billet 2 in the container 1. By applying pressure, the hollow profile 8 is continuously extruded from the die 4. After the extrusion is completed, the mandrel 5 is moved forward by a predetermined amount as shown in FIG. 3 to insert the large diameter portion 5B into the hole of the die 4,
As a result, the unpressed material remaining between the tips of the tongue portions 10 of the die 4 is extruded, and then the mandrel 5 is moved backward as shown in FIG.
Then, the discard 9 is knocked down by the discard shear and removed from the die 4. At this time, tongs 1
0 Thickness t (D2-D3) of the unpressed material remaining on the tip side
Is extremely small, about 1.29 mm, so
Compared with the conventional tool shown in FIGS. 5 to 8, the discard 9 can be knocked off with a small force, and damage to the tongue portion 10 can be prevented from being reduced.

[0011]

As described above, according to the hollow product extruding tool and the hollow product extruding method of the present invention, by forming the die side end of the mandrel in a stepped shaft shape, the tongue tip ends of the die are separated. Provide a large-diameter part with an outer diameter that is approximately equal to the distance, and insert this large-diameter part into the die at the end of extrusion to extrude the unpressed material in the die, and remove the thickness of the unpressed material remaining on the tip side of the tongs. Since it is made small, it does not require a large force when cutting and removing the discard with a shear, so even if it is a thin and long tongue part, it can be prevented from being damaged and the die has a long life. Can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a hollow product extruding tool according to the present invention.

FIG. 2 is a front view of a die.

FIG. 3 is a diagram showing a state in which a mandrel has been moved forward after completion of extrusion processing.

FIG. 4 is a diagram showing a state in which the mandrel is moved backward and pulled out from a discard.

FIG. 5 is a cross-sectional view showing a conventional extrusion tool.

FIG. 6 is a diagram showing an extruded state.

FIG. 7 is a view showing a state in which the mandrel is moved backward after the completion of extrusion processing.

FIG. 8 is a front view of a die including a tongue portion.

[Explanation of symbols]

 1 Container 2 Billet 3 Extrusion Tool 4 Die 5 Mandrel 5A Small Diameter 5B Large Diameter 6 Loose Dummy 7 Stem 8 Extruded Profile 9 Discard 10 Tongs

Claims (2)

[Claims] 1. A die including a tongue portion for defining the outer surface shape of the extruded profile and a mandrel for defining the inner surface shape of the extruded profile, the mandrel having a die side end formed in a stepped shaft shape. As a result, a small-diameter portion that is inserted into the die during normal extrusion and regulates the inner surface shape of the extruded shape, and an outer diameter that is larger than this small-diameter portion and is approximately the same as the tip-to-tip distance of the tongs A hollow product extruding tool having a large diameter portion that is sometimes inserted into a die. 2. After extruding a billet using the hollow product extruding tool according to claim 1, the mandrel is advanced to extrude the unpressed material remaining in the die at its large diameter portion, and then the mandrel is removed. A method for extruding a hollow product, which comprises retracting and removing the discard from the die.