JP2003290819A - Port hole die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a port hole die of excellent economy for consistently manufacturing a hollow extrusion die material of excellent dimensional accuracy without any uneven thickness, and reducing wastes of materials. <P>SOLUTION: A male die 2 comprises a ring part 4, a bridge part 5 provided along the inner radial direction of the ring part 4, and one or a plurality of forming projecting parts 6, 7 provided on a front end part in the extruding direction of the bridge part 5 to form a hollow part 31 of a hollow extrusion die material 30. The ring part 4, the bridge part 5, and at least the forming projecting parts 6 and 7 are integrated with each other. A female fitting recessed part 4c is formed on the front end face in the extruding direction of the ring part 4 along the extruding direction, and a plate-like female die 3 having a forming hole 13 to form an outer circumferential part 32 of a hollow extrusion die material 30 is tightly fitted to the female fitting recessed part 4c. In this condition, the front end faces in the extruding direction of the male die 2 and the female die 3 are formed flush. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a port hole die used for extrusion processing of a metal hollow extrusion mold material such as an aluminum alloy.

[0002]

2. Description of the Related Art For example, a porthole die is generally used for extrusion processing of an aluminum hollow extrusion molding material (30) as shown in FIG.

As shown in FIG. 7, the port hole die (51) includes a male die (52) for molding the hollow portion (31) of the hollow extrusion mold material (30) and an outer peripheral portion () of the hollow extrusion mold material (30). 32) is combined with a female mold (53) for molding.

In the male mold (52), as shown in FIGS. 7 and 8, a bridge portion (55) having an X-shaped rear view is provided inside the ring portion (54) integrally with the ring portion (54). The bridge portion (55) divides the axial hole of the ring portion (54) into four port holes (54a) (54a) (54a) (54a) and the front end portion of the bridge portion (55) in the extrusion direction. The hollow parts (31) (31) of the extruded mold material (30) are provided with first and second molding convex parts (56) (57) (57) (57) (57) corresponding to the shape. Then, the first and second molding convex portions (56) (5) on the front surface side in the extrusion direction of the bridge portion (55) in the ring portion (54).
Around the circumferences of 7), there is provided a welding recess (59) forming a welding chamber (58) into which the extruded material divided by the bridge (55) is joined and welded.

The male mold (52) is a hollow extrusion mold material (30).
A convex step provided on the female mold (53) having a molding hole (60) corresponding to the shape of the outer peripheral part (32) of the male and female molds (52) (53) along the entire periphery of the facing surface. (52a) and concave step (5
3a) and the male bearing parts (56a) (5a) (5) at the tips of the first and second molding convex parts (56) (57) of the male mold (52).
7a) ... are aligned in the molding hole (60), that is, they are assembled in a centered state.

When the extruded material is pushed into the port hole die (51), the extruded material divided by the bridge portion (55) is merged and welded in the welding chamber (58) to form the first and the second portions. 2 Molding projections (56) (57) ... and molding holes (6
It is pushed into the molding gap formed by (0) and (3) to mold the desired hollow extrusion mold material (30).

[0007]

However, it is difficult for the above-mentioned conventional porthole die (51) to stably push out a high-quality product. That is, in the above porthole die (51), the male and female molds (52) (53) are
Since the annular convex step portion (53a) of the female mold (53) is fitted and combined with the annular convex step portion (52a) of the male mold (52), both male and female molds (52) (53) are formed. A relatively long distance is formed from the fitting peripheral surface which is in contact with to the molding gap. Therefore, for example, when the die (51) is bent by the pressure received from the extruded material during extrusion, the displacement between the molding projections (56) (57) ... It is difficult to maintain a proper centering state due to a large difference between the two, and it is difficult to stably manufacture a high-quality product having excellent dimensional accuracy due to uneven thickness.

The male die (52) is formed by cutting a cylindrical body of die steel or the like, and the tip of the molding convex portions (56) (57) ... Is formed in the male die (52). Since the ring portion (54) is provided so as to project from the front end face in the extrusion direction, the molding convex portions (56) (57) are formed from the cylindrical body including the length of the projecting portion.
… Unnecessary parts around the tip are scraped off and molded convex parts (56)
(57) ... is formed. For this reason, there are many parts that are scraped off when forming the male mold (52), and there is a problem that the material is wasted more than necessary.

That is, the first object of the present invention is to enable stable production of a hollow extruded mold material having an excellent dimensional accuracy without uneven thickness, reducing waste of material and being economical. It is to provide hole dice.

On the other hand, in the above-mentioned conventional porthole die (51), as shown in FIG. 5, an extruded mold material (30) having a thin partition wall between adjacent hollow portions or an outer peripheral wall between the hollow portion and the outer peripheral surface is used. When extruding an extruded material having a thin wall portion such as a thin extruded material, it is difficult to stably extrude a high quality product. That is, for example, when a hollow extruded mold material as shown in FIG. 5 is extruded, the welding chamber (58)
The first molding protrusion (5) corresponding to the thin wall portion (33) in
Since the narrow welding portions (58a) (58a) between the 6) and the second forming convex portions (57) (57) (57) (57) are narrow, the narrow welding portions (58a) (58a) (58a) (58a) There is a problem in that the extruded material does not sufficiently enter into) ..., and the product tends to be an uneven thickness product having a non-uniform thickness such as thinness.

Further, since the extruded material does not sufficiently enter into the narrow welded portion (58a), a difference occurs in the pressure acting on the outer peripheral surfaces of the second molding convex portions (57) (57) ... In the circumferential direction, The second molding convex portions (57) (57) ... tend to be bent and displaced, and it may not be possible to stably manufacture high-quality products.

A second object of the present invention is to provide a porthole die capable of reliably pushing an extruded material into a narrow weld portion and stably manufacturing a high quality product. To do.

[0013]

In order to achieve the above-mentioned first object, in the porthole die according to the first aspect of the present invention, a male die is provided along a ring portion and an inner radial direction of the ring portion. A bridge portion, and one or a plurality of molding convex portions that are provided at the front end portion in the extrusion direction of the bridge portion and that mold the hollow portion of the hollow extrusion mold member, the ring portion, the bridge portion, and at least one of In the porthole die integrally formed with the molding convex portion, the ring portion has a female fitting concave portion formed on the front end face in the extrusion direction along the extrusion direction,
In the female mold fitting recess, a plate-shaped female mold having a molding hole for molding the outer peripheral portion of the hollow extruded mold material is tightly fitted,
It is characterized in that the male die and the female die are formed so that their front end faces in the extrusion direction are flush with each other.

According to the first aspect of the present invention, since the female die is tightly fitted in the female die fitting concave portion of the male die, the fitting position and the molding gap for aligning the male and female dies are set. Even if the porthole die bends during extrusion, the alignment between the molding protrusion and the molding hole caused by this deflection can be maintained with high accuracy even during extrusion. Thus, it is possible to stably manufacture a hollow extruded mold material having excellent dimensional accuracy without uneven thickness. Further, since the plate-shaped female die is fitted into the male female die fitting concave portion, the molding convex portion arranged in a facing state in the molding hole is also extruded from the front end face in the extrusion direction of the ring portion. It is formed by retreating backward in the direction. Therefore, the waste of the material is reduced, and the die effectively uses the material and is excellent in economic efficiency. Further, since the female die is fitted in the female die fitting recess, a large backer accommodation space can be provided for supporting the female die from the front side in the extrusion direction, and a large backer can be accommodated to stabilize the female die. Can be supported. Moreover, when the male and female dies are fitted together, their front faces in the extrusion direction are formed flush with each other, so there is no need to process the back surface of the backer, and the burden of applying this die is reduced. It

In the first aspect of the invention, it is preferable that the female mold is set to have a thickness corresponding to a bearing length of the molding hole. According to this structure, even if the bearing is worn, the female die can be replaced at a relatively low cost.

In order to achieve the above-mentioned second object, the porthole die according to the second invention has at least one hollow portion, and a hollow portion between the hollow portion and the outer peripheral surface or an adjacent hollow portion. A port hole die for extrusion molding of a hollow extruded material having a thin wall portion between parts, wherein a material supply hole narrower than the port hole is provided in a bridge part that divides the axial hole of the ring part into a plurality of port holes. Is provided so as to pass through in the extrusion direction, and the front side opening in the extrusion direction of the material supply hole is provided so as to face the narrow width welding portion corresponding to the thin wall portion in the welding chamber.

According to the second aspect of the invention, the material supply hole is provided in the bridge portion so as to penetrate in the extrusion direction, and the front side opening in the extrusion direction of the material supply hole has a narrow width corresponding to the thin wall portion in the welding chamber. Since it is provided facing the welding portion, the extruded material pushed into the material supply hole is surely pushed into the narrow welding portion. Therefore, it is possible to stably manufacture a high-quality product without causing a defect such as thinning due to lack of the extruded material in the narrow weld portion. Further, since the extruded material is surely pushed into the narrow sandwiching portion, there is no pressure difference on the outer peripheral surface of the molding convex portion that molds the hollow portion in the extrusion mold material, or it becomes small and the molding convex portion hardly bends and is displaced. . Therefore, a high quality product can be stably manufactured. Moreover, since the material supply hole is narrower than the port hole, the strength of the bridge portion is not extremely reduced.

In the second aspect of the invention, the material supply hole has an opening on the rear end side in the extruding direction provided in an inner region of the rear surface of the bridge portion, and on the front end side in the extruding direction, is radially outward of the ring portion. It is preferably bent and provided. According to this structure, the partition wall between the port hole and the material supply hole in the bridge portion can be formed relatively thick, and the strength of the bridge portion can be ensured.

In the second aspect of the invention, it is preferable that the material supply hole has a main portion formed as a drill hole. According to this structure, it is possible to save time and labor as compared with the case where the material supply hole is formed by electric discharge machining or the like, and it is possible to reduce the machining cost.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A porthole die according to the present invention will be described below based on the embodiments shown in the drawings.

The porthole die (1) of the present embodiment shown in FIGS. 1 to 4 has a circular first hollow portion (31a) as shown in FIG. 5 at regular intervals around the first hollow portion (31a). ) Near the four small circular second hollow portions (31b) (31b) (31
b) (31b) is formed, and the first hollow portion (31a) and each second
Used for forming a prismatic hollow section extrusion mold material (30) having thin wall portions (33) (33) (33) (33) between the hollow portions (31b) (31b) (31b) (31b) It is a thing. The hollow extrusion mold material extruded by the porthole die (1) of the present invention is not limited to the extrusion mold material (30) as described above, and has at least one hollow part, Hollow extrusion mold materials having various other shapes may be used as long as they are hollow extrusion mold materials having a thin wall portion between the hollow portion and the outer peripheral surface or between adjacent hollow portions.

As shown in FIGS. 1 to 4, the porthole die (1) of this embodiment is a male mold (2) for molding the first and second hollow portions (31) of the hollow extruded mold material (30). And a female mold (3) for molding the outer peripheral part (32) of the hollow extrusion mold material (30)
And become the main components.

As shown in FIGS. 1 and 2, the male mold (2) is a cylindrical mold member made of a steel material such as die steel, and extends along the inner radial direction of the cylindrical ring portion (4). The bridge portion (5) is integrally formed.

As shown in FIGS. 1 and 2, the ring portion (4) is notched along the entire periphery of the front end face in the extrusion direction, whereby the front end portion is fitted into the fitting convex step (4a). ) Is formed as. Further, the ring portion (4) has a female fitting recess (4c) formed on the front end face in the pushing direction along the pushing direction so that the female die (3) can fit tightly. . In other words, the female fitting recess (4c) is formed by expanding the shaft hole of the ring portion (4) at the front end in the extrusion direction, and the expanding step (4d) is formed in the female mold (3d). ) Is brought into contact with the outer peripheral edge portion of the rear end face in the extrusion direction. The female fitting recess (4c) is formed corresponding to the female mold (3), and its shape is circular and its depth is equal to the thickness of the female mold (3) plate. In the state where the female die (3) is fitted, the female die (3) and the front end face in the extrusion direction of the ring portion (4) are flush with each other.

Further, the first portion, which will be described later, on the front side in the extrusion direction of the bridge portion (5) in the axial hole of the ring portion (4).
And around the second molding convex portions (6) (7) ..., a welding concave portion (9) for forming a welding chamber (8) in which the extruded material divided by the bridge portion (5) is joined and welded is provided. There is.

The bridge portion (5) is, as shown in FIG.
It is formed in a substantially X shape when viewed from the rear, and has a central intersection (5
a) and four bridges (5b) (5b) (5b) (5b) radially extending from the central intersection (5a) in a radial direction, and the axial hole of the ring (4) is 4 One port hole (4f) (4f) (4
f) It is supposed to be divided into (4f). These port holes (4f) (4f) ... are prismatic hollow extrusions (30)
Are provided corresponding to each side of the four circumferences.

The central intersection (5) of the bridge (5)
b) is formed in a substantially circular shape in the rear view and has a certain area in the rear view. As shown in FIGS. 3 and 4, the front end portion of the central intersecting portion (5b) in the extrusion direction is tapered so that the front end edge has a first hollow portion (31a) of the extrusion molding material (30). The first molding convex portion (6) for molding is integrally formed. This first molding convex portion (6)
The first male bearing portion (6a) is formed by slightly bulging its tip end outwardly, and the first male bearing portion (6a) is formed.
Are provided so as to face the female fitting hole portion (4c) of the ring portion (4), that is, the molding hole (13) of the female die (3).

On the other hand, as shown in FIG. 2, the bridge portions (5b) (5b) ... Are arranged at 90-degree intervals centering on the central intersection portion (5b) in the rear view. Then, as shown in FIGS. 1 and 3, the hollow extruded mold material (30) is provided at a position close to the first molding convex portion (6) on the front end face in the extrusion direction of each bridge portion (5b) (5b). The second molding protrusions (7), (7), ... For molding the second hollow portions (31b), (31b) ... That is, as shown in FIG. 1, these second molding protrusions (7), (7) ... are extruded in the vicinity of the first molding protrusions (6) on the bridge portions (5b), (5b). The second molding projection pin (1) is inserted into the insertion small holes (10) (10) (10) (10) formed along the direction.
The base ends of (1), (11), (11), and (11) are inserted and firmly fixed by welding or the like. Each second molding protrusion (7)
Like the first molding convex portion (6), the tip end thereof bulges slightly outward to form the second male bearing portion (7a),
The second male bearing portion (7a) is provided so as to face the female fitting hole portion (4c) of the ring portion (4).

Then, as shown in FIG. 1, the second forming protrusions (7) (7) (7) (7) (7) (7) (7) are located in the vicinity of the first forming protrusion (6) in the plane normal to the extrusion direction. ) Are arranged, and due to the gap between the first male bearing portion (6a) and the second male bearing portions (7a) (7a) ..., the thin wall portions (33) (33) (33) of the extruded mold material (30). It is supposed to mold (33). Therefore, the gap between the first molding convex portion (6) and each second molding convex portion (7) is formed to have a narrow width to form a narrow welding portion (8a). In 8a), the extruded material forming the thin wall portion (33) is joined and welded. The width of the narrow weld portions (8a) (8a) ... (In the present embodiment, the first molding convex portion (6) and the second molding convex portion (7))
The distance) is determined in consideration of the thickness of each thin wall portion (33) (33) ... Of the extruded mold material (30).

Further, the bridge portion (5) has a structure shown in FIGS.
And as shown in FIG. 4, four material supply holes (12) (12)
(12) (12) is provided so as to penetrate in the extrusion direction. These material supply holes (12) (12) ... are narrow welding parts (8a)
(8a) ... is provided corresponding to. That is, on the rear end side in the extrusion direction, the material supply holes (12) (12) ... Correspond to the bridge portions (5b) (5b) ... Of the bridge portion (5) in the radial direction of the central intersection (5a). While being opened at the inward position, the first molding convex portion (6) and the second molding convex portion (6) are formed on the front end side in the extrusion direction.
It is opened at the base end of the gap between the molding projections (7), (7), and, therefore, the opening of the material supply holes (12) (12) at the front end side in the extrusion direction is the narrow weld (8a) ( 8a) ...

As shown in FIG. 4, each material supply hole (12) is formed in a bent shape, and the rear end side in the extrusion direction is formed as a linear guide portion (12a) along the extrusion direction, while the extrusion direction is formed. The front end side is formed as a tilt guide portion (12b) that tilts radially outward of the male mold (2) in the extrusion direction. In the present embodiment, the linear guide portion (12a) is drilled from the rear surface side of the bridge portion (5), while the inclined guide portion (12b) is formed into the second forming convex portion pin (11).
Before the installation of (11) ..., it is provided by electric discharge machining from the front side of the bridge part (5). Further, the cross-sectional area of each material supply hole (12) is narrower than the cross-sectional area of the port hole (4f), so that the strength of the bridge portion (5) is not extremely reduced. . The straight guide portion (12a) is formed to have a substantially circular cross section, while the inclined guide portion (12b) is formed to have a substantially oval cross section.

On the other hand, the female die (3) is a disk-shaped body made of cemented carbide or the like, and a substantially square molding hole (13) is provided in the center of the female die (3) so as to penetrate the female die (3). Has been. The molding hole (13) is for molding the outer peripheral portion (32) of the extrusion mold material (30), and is appropriately changed depending on the extrusion mold material to be manufactured. It should be noted that knock pin through holes (3a) (3a) are provided at predetermined symmetrical positions of the female die (3).

Then, the female die (3) having the above construction is combined with the male die (2) to form the porthole die (1). That is, the female mold (3) is tightly fitted into the female fitting hole (4c) of the male mold (2) to combine them. At this time, the first male bearing portion (6a) of the first molding convex portion (6) and the second male bearing portions (7a) (7a) of the second molding convex portions (7) (7) ... It is in a state of facing the inside of the molding hole (13) of (3). Further, in a state where both are combined, the bridge part (5) of the male mold (2) in the extrusion direction and the female mold (3).
A welding chamber (8) for joining and welding the extruded material divided by the bridge portion (5) is formed between the rear surface and the rear surface in the extrusion direction. Further, in the state where both (2) and (3) are combined, the front end faces in the extrusion direction of the male die (2) and the female die (3) are formed flush with each other.

As described above, since the female die (3) is tightly fitted in the female fitting concave portion (4c) of the male die (2),
The distance between the fitting position for centering the male and female dies (2) and (3) and the molding gap is shortened, so that even if the port hole die (1) is bent during extrusion, this bending does not occur. Molding protrusions (6) (7) ... and molding holes (13) caused by
The centering condition with and is maintained with high accuracy even during extrusion,
It is possible to stably manufacture the hollow extruded mold material (30) having excellent dimensional accuracy without uneven thickness. Further, since the plate-shaped female die (2) having a thickness corresponding to the bearing length of the molding hole (13) is fitted in the female fitting recess (4c) of the male mold (2), the molding hole is formed. The first molding convex portion (6), which is arranged in an opposed state in the (13), is also formed integrally with the bridge portion (5) by retreating from the front end face in the extrusion direction of the ring portion (4) to the rear in the extrusion direction. It Therefore, the first molding convex portion (6) can be formed by cutting out from the cylindrical body corresponding to the length of the male die (2), the waste of the material is reduced, and the economy is excellent. Further, since the female die (3) is fitted in the female die fitting concave portion (4c), it is possible to secure a large accommodation space for the backer (14) that supports the female die (3) from the front side in the extrusion direction. it can.

Next, the porthole die (1) is attached to a backer (14) which has a mold material lead-out hole (14a) in the shaft core and supports the pressure acting on the female mold (3) from the back. This porthole die (1) has a front surface in the extrusion direction flush with each other when the male and female dies (2) and (3) are fitted to each other. There is no need to process the above, and the burden when using the die (1) is reduced.

Thus, this porthole die (1)
Is attached to the outlet of the container section of the extruder, and the billet as the extrusion material is loaded into the container section. Then, the stem of the billet is advanced from behind. The billet is pushed out in accordance with this forward movement, and the extruded material is pushed into the port holes (4f) (4f) ... And also into the material supply holes (12) (12). The extruded material pressed into the material supply holes (12) (12) ... has a narrower weld portion (8a) than the opening on the front side in the extrusion direction.
The extruded material is supplied to the narrow weld portions (8a), (8a), guided by the (8a). In this way, since the front side openings of the material supply holes (12) (12) ... in the extrusion direction are provided so as to face the narrow welding part (8a) in the welding chamber (8), the inside of the material supply hole (12) The extruded material pushed into is surely pushed into the narrow weld (8a),
It is possible to stably manufacture a high-quality product without causing defects such as thinness due to lack of the extruded material in a). Further, since the extruded material is surely pushed into the narrow sandwiching portion (8a), the pressure difference is eliminated or reduced on the outer peripheral surfaces of the second molding convex portions (7) (7) ... (7) (7) ... hardly bend and displace, and high quality products can be manufactured stably.

Further, the material supply hole (12) has an opening on the rear end side in the extrusion direction provided in the inner area of the rear surface of the bridge portion (5), and the linear guide portion (12a) and the inclined guide portion (12b).
Since and are bent, the partition wall between the port hole (4f) and the material supply hole (12) in the bridge part (5) can be formed relatively thick, and the bridge part (5) of the bridge part (5) can be formed. The strength can be secured.

Further, since the linear guide portion (12a) occupying the main part of the material supply hole (12) is drilled, compared to the case where it is formed by electric discharge machining or the like over the entire length of the material supply hole (12). As a result, the time and labor can be saved, and the processing cost can be reduced.
7 and FIG. 7 show another embodiment of the present invention. The porthole die (1) according to the above embodiment has the following points.
Different from

That is, the porthole die (20) according to another embodiment is an extrusion die member different from the extrusion die member (30) produced by the porthole die (1) according to the above embodiment, A first molding convex portion (21) for molding a substantially quadrangular first hollow portion in the center of the extruded mold material in cross section, and a small circle in cross section corresponding to each corner of the first molding convex portion (21). Second molding convex part (22) (22) (22) (22)
Of the third molding projections (23) (23) having a substantially oval cross section corresponding to the pair of opposing sides of the first molding projection (21), and the first molding projection (21). A fourth molding convex portion (24) having a small circular shape in cross section, provided on each side, two corresponding to the other pair of sides.
(24) (24) (24) are provided. Material gaps between the first molding convex portions (21) and the other molding convex portions (22) (23) (24), that is, the narrow welding portions (25) (25) (25), are respectively provided with material supply holes. (26) is provided so as to face the opening on the extrusion direction side. In particular, the material supply holes (26) (26) in the narrow weld portion (25) between the first molding convex portion (21) and the fourth molding convex portion (24) are one supply hole (26). Narrow welded portions (25) (25) (25) between the first forming protrusions (21) and the fourth forming protrusions (24) (24) and the adjacent fourth forming protrusions (24) (24)
Extruded material can be supplied to the.

In the porthole die (20) according to the other embodiment, the same effect as in the above embodiment can be obtained.

The porthole dice (1) (20) according to the embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned two embodiments, and the scope is not deviated from the scope thereof. Various changes are possible.

In each of the above-mentioned embodiments, the porthole dies (1) (20) used for the extrusion mold material having the thin wall portion between the adjacent hollow portions have been described, but the thin wall portion is provided between the hollow portion and the outer peripheral surface. The same can be applied to a porthole die used for an extrusion mold material having a portion.

Needless to say, various design changes can be made to the detailed structure such as the material, the shape and size of each member.

[0044]

As described above, according to the porthole die according to the first aspect of the present invention, the distance between the fitting position for centering the male and female dies and the molding gap is shortened, and the porthole die The alignment condition between the molding convex portion and the molding hole caused by bending can be maintained with high accuracy, and a hollow extrusion mold material having excellent dimensional accuracy without uneven thickness can be stably manufactured. Further, the molding convex portion arranged in the molding hole so as to be opposed to the molding hole is formed so as to recede rearward in the extrusion direction from the front end face in the extrusion direction of the ring portion. Therefore, it is possible to save the material for forming the molding convex portion, which is excellent in economic efficiency. Further, a large space can be provided for the backer that supports the female die from the front side in the extrusion direction, and a large backer can be accommodated to stably support the female die. Moreover, when the male and female dies are fitted together, their front faces in the extrusion direction are formed flush with each other, so there is no need to process the back surface of the backer, and the burden of applying this die is reduced. It

On the other hand, according to the porthole die of the second invention, the extruded material pushed into the material supply hole provided in the bridge portion is surely pushed into the narrow welding portion.
Therefore, it is possible to stably manufacture a high-quality product without causing a defect such as thinning due to lack of the extruded material in the narrow weld portion. Further, the pressure difference is eliminated or reduced on the outer peripheral surface of the molding convex portion that molds the hollow portion in the extrusion mold material, and the molding convex portion hardly bends and displaces, so that a high quality product can be stably manufactured. Moreover, since the material supply hole is narrower than the port hole, the strength of the bridge portion is not extremely reduced.

In the second aspect of the present invention, the material supply hole is formed such that an opening on the rear end side in the extrusion direction is provided in an inner region of the rear surface of the bridge portion and is bent on the front side in the extrusion direction. Has an advantage that the partition wall between the port hole and the material supply hole in the bridge portion can be formed relatively thick, and the strength of the bridge portion can be secured.

In the second aspect of the invention, when the material supply hole is formed by drilling a main portion thereof, it takes time and labor as compared with the case where the material supply hole is formed by electric discharge machining or the like. There is an advantage that the cost can be saved and the processing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a porthole die according to an embodiment of the present invention with a part cut away.

FIG. 2 is a rear view showing the porthole die.

FIG. 3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a cross-sectional view showing an example of a manufactured extrusion mold material.

FIG. 6 is a rear view showing another embodiment of the present invention.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a perspective view showing a conventional porthole die.

FIG. 9 is a rear view showing a conventional porthole die.

[Explanation of symbols] 1 ... Porthole Dice 4 ... Ring part 4c ... Female fitting recess 4f ... Port hole 5 ... Bridge 6 ... 1st molding convex part 7 ... Second molding protrusion 8 ... Welding chamber 8a ... Narrow welded part 12 ... Material supply hole 30 ... Extruded mold material 31 ... Hollow part 33 ... Thin wall part

Claims (5)

[Claims] 1. A male die for molding a ring portion, a bridge portion provided along the inner radial direction of the ring portion, and a hollow portion of a hollow extrusion molding member provided at a front end portion in the extrusion direction of the bridge portion. In a porthole die having one or a plurality of molding protrusions, the ring portion, the bridge portion, and at least one molding protrusion being integrally formed, the ring portion has a front end face in the extrusion direction. A female fitting recess is formed along the extrusion direction, and a plate-shaped female mold having a molding hole for molding the outer peripheral portion of the hollow extrusion mold material is tightly fitted into the female fitting recess. A porthole die in which the front end faces of the die and the female die in the extrusion direction are formed flush with each other. 2. The port hole die according to claim 1, wherein the female die has a thickness corresponding to a bearing length of the forming hole. 3. A porthole die for extrusion molding of a hollow extrusion molding material having at least one hollow portion, and having a thin wall portion between the hollow portion and an outer peripheral surface or between adjacent hollow portions. In the bridge portion that divides the axial hole of the ring portion into a plurality of port holes, a material supply hole narrower than the port hole is provided so as to penetrate in the extrusion direction, and the front end opening of the material supply hole in the extrusion direction is formed. Is provided so as to face a narrow width welding portion corresponding to the thin wall portion in the welding chamber where the extruded material divided by the bridge portion is joined and welded. 4. The material supply hole is formed such that an opening on the rear end side in the extrusion direction is provided in an inner region of the rear surface of the bridge portion, and is bent outward in the radial direction of the ring portion on the front end side in the extrusion direction. The porthole die according to claim 3, wherein 5. The material supply hole according to claim 3, wherein a main part of the material supply hole is formed as a drill hole.
Port hole dice described in.