JPS6145924Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extrusion die, and more particularly to an extrusion die used to produce a thick extruded section having a hollow portion with an extremely small diameter.

It is common practice to manufacture various shapes from metal materials such as aluminum or aluminum alloys by extrusion processing methods such as hot extrusion processing, but it is common practice to manufacture various shapes from metal materials such as aluminum or aluminum alloys. It is considered extremely difficult to manufacture a thick-walled cylindrical extruded section having the following characteristics, and in fact, it is almost impossible to manufacture it. . This is because when extruding a thick-walled cylindrical shape with an ultra-fine diameter, it is difficult to adjust the flow of the extruded metal material, and it is difficult to stably obtain holes with a predetermined ultra-fine diameter. This is because the lifespan of the extrusion die is extremely short due to breakage of the extremely small diameter portion of the mandrel.

For this reason, conventionally, when obtaining a thick-walled cylindrical product having a hollow part with an extremely small diameter, a solid shape without holes is first extruded using the usual method.
Next, a method is adopted in which holes are drilled into the extruded material using a drill, etc., but since it is necessary to drill holes with extremely small diameters, the drilling process may cause damage to the drill, etc. is extremely difficult,
In addition, it not only increases the number of machining steps, but also has drawbacks such as being limited in the machining depth in the longitudinal direction.

Furthermore, as a method and apparatus for forming an extruded product having micro-hollows, Japanese Patent Application Laid-Open No. 51-66351 discloses a method and apparatus in which the tip of the male mold faces the material inflow side of the extrusion hole of the female mold,
A technique has been disclosed to control the flow of the extruded material depending on the relative position and distance between the female mold and the male mold to form a microscopic hollow. Since the shape or size of the micro-hollows is only controlled by distance, the flow of material within the female mold cannot be sufficiently controlled, and the shape or size of the micro-hollows formed cannot be sufficiently controlled. There is a problem that an extruded product having uniform micro-hollows cannot be obtained because the size varies.

The present invention has been developed in view of the above circumstances, and an object of the present invention is to provide an extrusion die that can effectively extrude a thick-walled shape having a hollow part with an extremely small diameter. It is something.

In order to achieve this object, the extrusion die according to the present invention is composed of a female die having a chamber part and a bearing part, and a male die having a mandrel part, and the base of the mandrel part is placed inside the chamber part. The tip of the mandrel, which determines the diameter of the hollow part of the extruded section, is positioned so as not to protrude into the bearing part, and extends further forward from the tip of the protruding base of the mandrel part. The inner wall surface of the bearing part is configured as an inclined surface whose cross-sectional area gradually decreases toward the bearing part, and the inner wall surface of the bearing part is brought close to the bearing part without substantially forming a flat surface perpendicular to the extrusion direction. , the base of the mandrel portion is configured to have a conical shape that is substantially similar to the inclined surface, thereby making it possible to form a thick-walled shape having a hollow portion with an extremely small diameter. This makes manufacturing easier, eliminates the need for troublesome and difficult operations such as drilling, and allows the depth of the holes in the longitudinal direction to be unlimited.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, in FIGS. 1 to 3, reference numeral 2 denotes an extrusion die for processing metal materials such as aluminum or aluminum alloy, and is composed of a female die 4 and a male die 6. The female die 4 is provided with a chamber part 10 in the axial direction thereof, which includes a bearing part 8 narrowed to a small diameter.
Further, the inner wall surface of the chamber portion 10 is configured as a truncated cone-shaped inclined surface with the apex facing the extrusion direction, in other words, an inclined surface whose cross-sectional area gradually decreases toward the bearing portion 8. It is configured to reach the bearing portion 8 without substantially forming a flat surface perpendicular to the extrusion direction.

On the other hand, the male die 6 is provided with a bridge portion 12 that straddles its outer frame and two portholes 14 that serve as extrusion passages for the metal billet, and a conical mandrel base at the tip of the bridge portion 12. 16 is provided in a state of protruding into the chamber portion 10, and furthermore, a mandrel tip portion 18 is provided protruding from the tip of the mandrel base portion 16 in the extrusion direction. The tip portion 18 has an extremely small diameter suitable for forming a hollow portion of the extruded product, and is extremely short so that it is fixed within the chamber portion 10 and does not protrude into the adjacent bearing portion 8. has been done. Since the chamber portion 10 and the mandrel base portion 16 have substantially similar conical shapes, both wall surfaces are shaped to follow the flow line when the metal billet flows.

In the extrusion die 2 having such a configuration, when a metal billet housed in a container (not shown) is pressed from the back side of the male die 6 and introduced into the porthole 14, the metal billet is transferred from the porthole 14 to the chamber part 10. Mandrel base 16
A thick-walled cylindrical product having a desired ultra-thin diameter hole is extruded from the bearing part 8 through the gap 20 formed between the bearing part 8 and the bearing part 8.

When extruding such a metal billet, a strong pressing force acts on the surfaces of the mandrel base 16 and the mandrel tip 18, as well as a strong tensile force in the extrusion direction based on the frictional resistance of the flowing billet. However, since the wall surfaces of the chamber portion 10 and the mandrel base 16 are shaped along streamlines as described above, the frictional resistance is relatively small, and therefore the tensile force is also small, and the tip of the mandrel Since the length of the bearing part 8 is extremely short, the frictional resistance acting on its surface is also extremely small.Furthermore, there is a mandrel tip in the bearing part 8 where the flow path of the metal billet is most constricted and the frictional resistance is maximum. Since the portion 18 does not protrude, there is almost no possibility that the tip portion 18 will be torn off as in the conventional case, and moreover, the tip portion 18 is hardly peeled off as in the conventional case. This made it possible to obtain a functional extrusion die.

In this way, according to the extrusion die 2 described above, a thick cylindrical extruded section (shown in FIG. 7) having a hollow part with an extremely small diameter of, for example, 1.5 mmφ or less can be manufactured very easily. Since the mandrel tip 18 is not damaged as in the conventional case, there is no need to frequently replace the male die 6. Moreover, since the conventional drilling process is no longer necessary, the troublesome and difficult work is freed, and there is no restriction on the depth of the hole in the longitudinal direction of the product. Since hollow shapes of objects can be obtained very easily and the life of the extrusion die 2 is extended, processing costs, repair costs, etc. are reduced, and a large cost reduction can be achieved.

Further, an example in which the present invention is applied to an extrusion die for manufacturing an extruded section having a hexagonal cross section is shown in FIGS. 4 to 6.

In these figures, the inner surfaces of the bearing part 24 and the relief part 26 following this in the female die 22 are all hexagonal in cross section.
Since this embodiment is completely the same as the embodiment shown in FIGS. 1 to 3, the same reference numerals are given and the explanation thereof will be omitted. Also in this case, the wall surfaces of the chamber part 10 and the mandrel base 16 are shaped to follow the streamlines of the flow, and the mandrel tip 18 does not protrude inside the bearing part 24, so that the tip 18 is not exposed during the extrusion process. Without tearing off the portion 18, a thick-walled extruded section with a hexagonal cross section (FIG. 8) having a hollow portion with an extremely small diameter can be manufactured easily and at low cost. In addition, in an example of a product obtained using the die of the present invention shown in FIG. 8, A6063 was used as the material, and the distance between opposite sides a = 19 mm, and the hole diameter b = 1.05 mmφ.

In each of the above embodiments, the male die 6 includes a bridge portion 12 and two portholes 1.
Although the present invention is not limited to this in any way, for example, a male die having a cross-shaped bridge portion and four portholes may be used. Moreover, although examples of extruded shapes having circular and hexagonal cross sections have been shown as extruded products, they may also have octagonal or other cross-sectional shapes. Furthermore, the flow of the metal billet was adjusted by making the chamber part 10 of the female die 4, 22 into a truncated conical shape with low flow resistance, but it is not necessarily a truncated conical shape, and other shapes may be used. Even if it is, it does not depart from the scope of the present invention.

In addition, it goes without saying that various modifications and improvements can be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of an extrusion die according to the present invention, and FIGS. 2 and 3 are - and - sectional views, respectively, of FIG. 1. FIG. 4 is a plan view showing another embodiment of the present invention, and FIGS. 5 and 6 are - and - sectional views, respectively, of FIG. 4. FIGS. 7 and 8 are partial perspective views of thick-walled extruded sections having circular and hexagonal cross-sections manufactured according to two embodiments, respectively. 2...Extrusion die, 4,22...Female die,
6... Male die, 8, 24... Bearing part,
10...Chamber part, 12...Bridge part, 16
...Mandrel base, 18...Mandrel tip.

Claims (1)

[Scope of utility model registration request] It consists of a female die having a chamber part and a bearing part, and a male die having a mandrel part, and the base of the mandrel part projects into the chamber part, and extends further forward from the tip of the protruding base part of the mandrel part. The mandrel tip, which determines the diameter of the hollow part of the extruded section, is positioned so as not to protrude into the bearing part, and the inner wall surface of the chamber part has a cross-sectional area that gradually decreases toward the bearing part. The mandrel base is formed into a conical shape having a substantially similar shape corresponding to the inclined surface, so that the bearing portion is formed as an inclined surface without substantially forming a flat surface perpendicular to the extrusion direction. An extrusion die for manufacturing a thick-walled extruded section having a hollow part with an extremely small diameter.