JP2951251B2 - Extrusion Hollow Rice - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow die for extrusion for extruding a hollow profile.

[0002]

2. Description of the Related Art Conventionally, this type of extrusion hodice has a male mold having a mandrel forming a hollow portion of a profile,
It is constituted by a combination with a female mold having a forming hole for forming a profile outer peripheral portion. Then, by extruding an extruded material such as an aluminum alloy through the space between the mandrel and the forming hole, a hollow profile can be formed.

[0003] Further, in this type of extrusion hollowhead,
The length of the outer surface of the mandrel and the inner wall of the forming hole facing each other in the extrusion direction (that is, the bearing length) is made different depending on the distance between the two in each part, whereby the speed at which the extruded material is extruded is uniform in each part. It is thought to be. That is, in a portion where the distance between the outer periphery of the mandrel and the inner wall of the forming hole is small, the flow resistance when the extruded material is extruded is large. Therefore, the shorter the distance between the two, the shorter the bearing length, and the flow resistance when the extruded material is extruded is made uniform in each part.

[0004]

However, heretofore, the bearing length has been varied by cutting the outer periphery of the mandrel from the downstream side in the extrusion direction (hereinafter simply referred to as the downstream side). For example, as shown in FIG. 4 (A), when forming an extruded cylindrical body 101 in which one short side 101a has a rectangular cross section thinner than the other side.
Hollow rice 103 as illustrated in FIG. 5B and FIG.
Extrusion molding.

As shown in FIG. 4B, a female mold 105 of the hollow body 103 has a hole 107 having a rectangular cross section.
As shown in FIG. 5, the tip of the male mandrel 109 is formed into a columnar shape having a rectangular cross section which can be disposed in the formation hole 107. Further, the inner wall surface 107a for forming the short side 101a and the mandrel 1
The space between the 09 outer peripheral surfaces 109a is smaller than the space between the other portions. Therefore, the bearing length (0.4 mm) of the surfaces 107a and 109a is made shorter than other parts (1 mm),
The extruded material is extruded at the same speed between the portion constituting the short side 101a and the other portions. Also, surface 10
To shorten the bearing length of 7a and 109a,
Notch 1 on the outer periphery of mandrel 109 from the tip side (downstream side)
09b, and a cutout 107b is formed on the inner wall of the formation hole 107 from the same side.

When the cutouts 107b and 109b are formed as described above, a part of the extruded material may adhere to these portions during the extrusion molding and may accumulate to form a lump. Then, in some cases, the lump formed in the notch portion 109b peels off during extrusion molding, and the hollow portion 101b of the extruded cylindrical body 101 is removed.
(FIG. 4A) may be obstructed. In particular, when extruding a hollow material having a hollow portion of 3 mm square or less as in the case of the extruded cylindrical body 101, the depth of the notch portion 109b can be secured only up to about 0.5 mm, and such a lump is formed. Easy to do.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hollow extruder which can form a hollow material while preventing the hollow portion from being blocked.

[0008]

According to a first aspect of the present invention, there is provided a male mold having a mandrel forming a hollow portion of a profile, and a forming hole forming an outer peripheral portion of the profile. The extrusion mandrel which is formed of a combination with a female mold and has a bearing length between the outer periphery of the mandrel and the inner wall of the forming hole which is made different depending on the distance between the two in each part. A gist for extrusion is characterized in that the outer peripheral edge in the extrusion direction on the downstream side is disposed on the same plane as the tip surface of the mandrel.

According to a second aspect of the present invention, there is provided an extrusion hollow die according to the first aspect, wherein the male mold and the female mold are formed of a cemented carbide. Claim 3
The gist of the invention is that the inner wall of the forming hole facing the outer periphery of the mandrel is disposed with a predetermined choke angle.

[0010]

According to the first aspect of the present invention, the bearing length between the outer periphery of the mandrel and the inner wall of the forming hole is made different depending on the distance between the two at each part. . For example, when forming a rectangular cylinder having one side thinner than the other side, the bearing length of the surface on which the one side is formed is shortened by the outer periphery of the mandrel and the inner wall of the forming hole. In this case, the extruded material constituting the rectangular tube can be extruded at the same speed at any portion. Also,
In the present invention, the downstream edge of the outer periphery of the mandrel facing the inner wall of the formation hole is disposed on the same plane as the tip surface of the mandrel. In addition, such a configuration is, for example,
This can be achieved by providing a cutout portion for changing the bearing length on the upstream side.

For this reason, the notch does not exist on the tip end side of the mandrel, and a mass of extruded material is not formed. Therefore, in the extrusion holy dice of the present invention, it is possible to form a hollow profile while favorably preventing the hollow portion from being closed. According to a second aspect of the present invention, in addition to the configuration of the first aspect, the male mold and the female mold are formed of a cemented carbide. If abrasion occurs on the outer periphery of the mandrel or the inner wall of the forming hole, the dimensional accuracy and the like of the hollow profile to be extruded is reduced. However, in the present invention, these members are formed of a cemented carbide which is very hard to wear. For this reason, in addition to the effect of the first aspect of the invention, there is an effect that the hollow profile can be more precisely formed. In addition, as a cemented carbide, WC-Co system, WC-TiC-Co system, WC
Various materials such as -TiC-TaC-Co type can be used.

The invention described in claim 3 is the first or second invention.
In addition to the configuration described above, the inner wall of the forming hole facing the outer periphery of the mandrel is provided with a predetermined choke angle. At the time of extrusion molding, a stress acts on the downstream side so as to increase the gap between the outer periphery of the mandrel and the inner wall of the forming hole. In the present invention, since the inner wall of the forming hole has a choke angle, when this stress acts, the outer periphery of the mandrel and the inner wall of the forming hole can be kept parallel. Therefore, according to the present invention, in addition to the effect of the first or second aspect of the present invention, there is an effect that the hollow profile can be more precisely formed.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a cross-sectional view illustrating a configuration of an extrusion holy dice (hereinafter, simply referred to as a hollow dice) 1 of an embodiment. The hollow die 1 of this embodiment is configured by combining a male mold 5 having a mandrel 3 and a female mold 9 having a forming hole 7. For a detailed configuration of the formation hole 7, see the perspective view of FIG. Returning to FIG. 1 (A), the mandrel 3 is disposed at the center of the male mold 5 by a mandrel support member 11 arranged along the radial direction of the male mold 5, and on the upstream side of the male mold 5 A billet 13 made of an aluminum alloy is provided as an extruded material.

The billet 13 is pressurized by a stem (not shown), whereby the aluminum alloy constituting the billet 13 passes through the hollow dies 1. The distal end of the mandrel 3 is fitted at a predetermined interval with the inner wall of the forming hole 7, and the aluminum alloy is extruded through this interval to form an extruded cylindrical body 15 as a hollow material. A die backer 17 is provided downstream of the female mold 9.

Next, the configuration of the mandrel 3 and the formation hole 7 will be described in more detail. In this embodiment, FIG.
The extrusion mandrel 15 has a rectangular cross-section as shown in FIG. 1, and the mandrel 3 has an outer periphery corresponding to the hollow portion 15a, and the forming hole 7 has an inner wall corresponding to the outer peripheral portion 15b. The short side 15c of the rectangular cross section of the extruded cylindrical body 15 is 0.2 mm thick and thinner than the other sides (0.5 mm thick). For this reason, the distance between the inner wall surface 7a of the forming hole 7 for molding the short side 15c and the outer peripheral surface 3a of the mandrel 3 is as shown in FIG.
As shown in (B), the distance between other parts is narrower. Therefore, the bearing length (0.4 mm) of the surfaces 7a and 3a is made shorter than the other portions (1 mm) so that the extruded cylindrical body 15 is extruded at the same speed in any portion.

Here, in this embodiment, in order to shorten the bearing length of the surfaces 7a, 3a, the notch 3b is formed on the outer periphery of the mandrel 3 from the base end side (upstream side), and the female mold 9 is formed. The upstream side of the portion facing the surface 3a (surface 7a) is omitted. For this reason, the downstream edge of the outer periphery of the mandrel 3 is
It is arranged on the same plane as the tip surface 3c of the mandrel 3.
Therefore, the aluminum alloy extruded through the hollow body 1 is prevented from forming a lump around the front end face 3c, and the hollow lump is closed by the lump (that is, a hole is clogged). Can be satisfactorily prevented.

Next, various types of hollow tooth 1 of the embodiment designed in the same manner as in FIG. 2 and hollow tooth 103 of the comparative example designed in the same manner as in FIG. 4 are produced, and the holes are clogged by actually performing extrusion molding. Were compared. The configuration of each comparative example and example is as follows. Table 1 shows the results.

Comparative Example 1: Steel material for hot die SKD61 (J
The design was made in the same manner as in FIG. 4 using ISG4404).
The inner wall of the forming hole 107 was parallel to the outer periphery of the mandrel 109 (that is, the choke angle was 0 °). Comparative Example 2: A design was made in the same manner as in FIG. 4 using a cemented carbide mainly composed of WC, and the choke angle of the inner wall of the forming hole 107 was 0 °.

Example 1 A design was made in the same manner as in FIG. 2 using SKD61, and the choke angle of the inner wall of the formation hole 7 was 0 °. Example 2: Designed in the same manner as in FIG. 2 using the above cemented carbide,
The choke angle of the inner wall of the forming hole 7 was 0 °.

Embodiment 3: Using the above-mentioned cemented carbide, a design is made in the same manner as in FIG. 2, and the inner wall of the forming hole 7 approaches the outer periphery of the mandrel 3 at an inclination of 0.5 ° toward the downstream (choke angle 0.5
°).

[0021]

[Table 1]

As shown in Table 1, in Comparative Example 1, 300 m
Clogging occurred in the extrusion molding of
No hole clogging occurred even when 000 m extrusion molding was performed. Further, in Comparative Example 2, clogging occurred in the extrusion molding of 3000 m, but in Example 2, clogging did not occur even in the extrusion molding of 5000 m.

The comparative examples 1 and 1 or the comparative examples 2 and 2 have almost the same structure except for the cutout portions 3b, 107b and 109b. However, Example 1 was different from Comparative Example 1, and Example 2 was Comparative Example 2.
On the other hand, in all cases, clogging is significantly reduced. From this experimental result, in Examples 1 and 2, the downstream edge of the outer periphery of the mandrel 3 was arranged on the same plane as the tip surface 3c, so that the clogging could be significantly reduced. I understand.

Further, in Example 1 made using the SKD61, irregularities were generated due to wear of the hollow rod 1, but not in Example 2 made using a cemented carbide. This shows that the use of a cemented carbide as the die material allows the extrusion cylinder 15 to be formed more precisely.

Further, comparing Examples 2 and 3 using the same cemented carbide as the die material, the choke angle was 0.5 °.
In Example 3, the dimensional accuracy can be made extremely high as ± 0.2 mm, and the extruded cylinder 15 can be formed more precisely than Example 2 in which the choke angle is 0 °. Was.

Next, the function of the choke angle will be described. When the choke angle is 0 °, the gap between the outer surface 3a of the mandrel 3 and the surface 7a of the inner wall of the forming hole 7 is made downstream on the downstream side during the extrusion forming of the extrusion cylindrical body 15 as shown in FIG. Stress acts. The same stress acts on the outer periphery of the mandrel 3 and other surfaces of the inner wall of the forming hole 7. Thus, by providing the choke angle (α) as shown in FIG. 3B, when this stress acts, the outer periphery of the mandrel 3 and the inner wall of the forming hole 7 can be kept parallel. Therefore, in Example 3, Example 2
As compared with the above, the extruded cylindrical body 15 can be formed more precisely. As described above, in the present embodiment, it is possible to form the extruded cylindrical body 15 while favorably preventing the hollow portion 15a from being closed, and to use a cemented carbide as a die material or to reduce a choke angle. By providing them, the extruded cylinder 15 can be formed with higher accuracy.

It should be noted that the present invention is not limited to the above embodiment at all, and can be implemented in various modes without departing from the gist of the present invention. For example, in the above-described embodiment, the extrusion cylindrical body 15 having a rectangular cross section is formed as the hollow shape member. However, the present invention relates to an extrusion hollow body for forming other various shapes as the hollow shape member. Can be applied to

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and a perspective view illustrating a configuration of an extrusion hollow head of an embodiment.

FIG. 2 is a cross-sectional view illustrating the details of the configuration of an extruding cylinder and an extrusion hollowice of the embodiment.

FIG. 3 is a cross-sectional view illustrating the function of a choke angle by way of example.

FIG. 4 is a cross-sectional view illustrating details of the configuration of a conventional extrusion cylinder and extrusion hollowhead.

FIG. 5 is a perspective view showing a configuration of a mandrel of the extrusion hollow head.

[Explanation of symbols]

1. Hollow rice for extrusion 3. Mandrel
3b: Notch 3c: Tip surface 5: Male type
7 ... forming hole 9 ... female type 15 ... extrusion cylinder
15a ... hollow part

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takaji Shinozawa 5-11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industries Co., Ltd. (56) References Special Publication No. Sho 59-16532 (JP, B2) Special No. 51-43824 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21C 25/00 B21C 25/02 B21C 25/04

Claims (3)

(57) [Claims] The present invention comprises a combination of a male mold having a mandrel forming a hollow portion of a profile and a female mold having a forming hole forming an outer peripheral portion of the profile. In an extrusion holing machine in which bearing lengths are made different in accordance with the interval between the two parts in each part, the downstream end in the extrusion direction of the outer periphery of the mandrel facing the inner wall of the forming hole is arranged on the same plane as the tip surface of the mandrel. Hollow rice for extrusion characterized by being provided. 2. The extrusion hollow die according to claim 1, wherein said male die and female die are formed of a cemented carbide. 3. The extruding hollow dolly according to claim 1, wherein the inner wall of the forming hole facing the outer periphery of the mandrel is disposed with a predetermined choke angle.