JP2747434B2 - Extrusion dies that prevent deformation by using back pressure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion die, and more particularly to an extrusion die in which a mandrel is prevented from being deformed by utilizing a back pressure during extrusion.

[0002]

2. Description of the Related Art A hollow or semi-hollow material is extruded by a die having a male mandrel facing an extrusion opening of a female mold. Porthole dice as an example of such a dice are shown in FIGS.

[0003] In the figure, (110) is a female die,
(120) is a male die. A through-hole (111) is formed at the center of the female die (110), and the peripheral surface on the inlet side of the hole has a circular bearing portion (11).
2) And it is made. Incidentally, (113) is a relief portion. On the other hand, the male die (120) has a mandrel part (121) having a circular cross section at the center thereof and a circular bearing part (122) on the tip end peripheral surface of the mandrel part (121).
have. A plurality of bridge portions (123) extending in the radial direction and having their peripheral ends abutting or joined to the female mold portion are integrally formed on the outer periphery of the rear end portion of the mandrel portion (121). The molding material introduction space through which the molding material such as aluminum passes between the adjacent bridge portions (124)
Are formed.

[0004] The above-mentioned dice female mold (110) and dice male mold (120) are combined to form a dice male mold (120).
Both ends of the mandrel part (121) face the extrusion hole (111) of the female female die (110) and the male and female bearing parts (112)
(122) are opposed to each other with an annular forming gap (130) therebetween.

In the porthole dice shown in FIGS. 4 and 5,
During extrusion, the molding material such as aluminum is a male die (120
), Are passed through the molding material introduction space (124), merged in the welding chamber (140) around the male mandrel (121), and dies from the molding gap (130). It is extruded into the relief (113) of the mold (110).

[0006] In the above-mentioned porthole dice,
As shown by an arrow in FIG. 4, an extruding pressure is applied to the mandrel portion (121) of the male die (120) from the rear in the extruding direction. And the dimensional accuracy of the extruded material is deteriorated.

[0007] Such a defect occurs not only in a porthole die but also in a die having a bridge portion as shown in FIG. The dice shown in FIG.
As shown in FIG. 7, an extruded material (300) having a circular hollow portion (301) at the center and an opening (302) communicating with the hollow portion (301) on the upper surface is manufactured. The hollow part (301) and the opening part (302)
The male mandrel part (221) for forming the hole is integrally arranged facing the extrusion hole (211) of the female part (210), and the inner peripheral bearing part (212) of the extrusion hole (211). A molding gap (230) is formed between the outer peripheral bearing portions (222) of the mandrel portion (221). (213)
Is a relief part. Also, at the rear end of the mandrel part (221), the molding gaps (230) (230)
), Two reinforcing bridges (240) (240), which are bridged at both ends of the female part (210), are linearly formed integrally with the rear end of the mandrel. Between adjacent bridge portions (240) and (240), that is, the bridge portion (240)
) (240) and the mandrel part (221) are formed with molding material introduction spaces (250) on both sides in the thickness direction (the direction perpendicular to the paper surface).

In the die shown in FIG. 6, a molding material such as aluminum is diverted at a bridge portion during extrusion and then passes through a molding material introduction space (250) to form a welding chamber (260) around a male mandrel portion (221). And extruded from the molding gap (230), during which the mandrel (221) receives a large extrusion pressure as indicated by the arrow. For this reason, the mandrel part (221) is also liable to be deformed and the dimensional accuracy of the extruded material is likely to be deteriorated.

The present invention has been made in view of such a technical background, and an extruding die which can prevent deformation of a mandrel portion due to an extruding pressure and can obtain an extruded material having excellent dimensional accuracy. It is intended to be provided.

[0010]

In order to achieve the above object, the present invention, referring to the reference numerals in the drawings, shows a male mandrel section (21) in an extrusion hole (11) of a female section (1). ) Is formed, a molding gap (4) is formed between the inner peripheral bearing portion (12) of the extrusion hole (11) and the outer peripheral bearing portion (22) of the mandrel portion (21), and the mandrel portion (21) is formed. The outer periphery of the rear end portion extends radially and the peripheral end portion is a female mold portion (1).
Bridge parts (23) abutted or joined to
Are formed integrally, so that the adjacent bridge portion (23)
A die having a molding material introduction space (24) formed between the (23) and the outer periphery of the rear end of the mandrel (21) is provided at a position between the adjacent bridges (23) and (23). A back pressure utilization portion (25) having a back pressure receiving surface (25a) projecting radially outward and directing the extrusion direction at right angles to the extrusion direction is formed, and the mandrel portion (21) and the bridge portion (23) are formed. )
And behind the back pressure utilization part (25), the molding material introduction space (3
A plate (3) having a plate (3) is provided, and a gap (5) is provided at least between the plate (3) and the mandrel part (21) and the back pressure utilization part (25). The purpose of the present invention is to provide a die for preventing deformation by utilizing a back pressure. In this case, the size of the gap (5) is preferably set to 0.5 mm or more.

[0011]

During the extrusion, an extruding pressure is applied to the plate (3) in the extruding direction, but between the plate (3) and the back pressure utilization part (25) and the mandrel part (21) of the male die (2). Since the gap (5) is formed, the deformation of the plate (3) is absorbed by the gap (5), and the extrusion pressure applied to the plate (3) is reduced by the back pressure utilization section (25) and the mandrel section (2).
It does not directly participate in 1). The mandrel portion (21) is subjected to an extrusion pressure by the molding material flowing toward the molding gap (4), and at the same time, is filled into the molding material introduction space (24) and the welding chamber (6) of the male die (2). The back pressure in the direction opposite to the pushing direction acts on the back pressure receiving surface (25a) of the back pressure utilizing portion (25) due to the material, so that the mandrel portion (2
The extrusion pressure applied to 1) is canceled, and the mandrel section (2
The deformation of 1) is prevented.

[0012]

1 to 3 show an embodiment in which the present invention is applied to a porthole die.

In FIG. 1, (1) is a female die,
(2) is a male die. In the female die, a through-hole (11) is formed at the center, and a peripheral surface on the inlet side of the through-hole is formed as a circular annular bearing portion (12). (13) is a relief portion. On the other hand, the male die (2) has a mandrel part (21) having a circular cross section at the center thereof and a circular annular bearing part (22) on the peripheral surface of the tip of the mandrel part. A plurality of bridge portions (2) extending radially and having a circumferential end contacting the female die are provided on the outer periphery of the rear end of the mandrel (21).
3) is formed integrally, so that the adjacent bridge (2
3) A plurality of molding material introduction spaces (24) through which a molding material such as aluminum is passed are formed between (23).

Further, a back pressure utilization portion (25) is integrally formed on the outer periphery of the rear end portion of the mandrel portion (21) with both circumferential ends connected to the adjacent bridge portions (23). I have. This back pressure utilization part (25) is used as the molding material introduction space (24)
Projecting radially outward to nearly half the height of the
The rear end face matches the rear end face of the mandrel part (21), and the front end face extends in the extrusion direction to nearly half the length of the bridge part (23) in the extrusion direction. The front end face of the back pressure utilizing portion (25) is a back pressure receiving surface (25a) perpendicular to the extrusion direction and oriented in the extrusion direction. Die male type (2)
On the rear surface, the bridge portion (23) excluding the peripheral end portion, the back pressure utilizing portion (25), and the mandrel portion (21) are provided so as to be retracted in the pushing direction.

Further, a plate-shaped plate (3) having the same outer diameter as the male die is formed behind the male die (2). The plate (3) has a baffle part (31) having a cross-sectional shape equal to the cross-sectional shape of the mandrel part (21) and the back pressure utilization part (25) of the male die (2) at the center, and a baffle part (31). It has a bridge portion (32) extending radially from 31). The circumferential position of the bridge portion (32) is the same as that of the bridge portion (23) of the male die (2).
And the thickness in the circumferential direction is set to be the same, so that the molding material in the die male mold (2) is provided between the adjacent bridge portions (32) and (32) of the plate (3). A molding material introduction space (33) having the same cross-sectional shape as the rear end section of the introduction space (24) is formed.

The female die (1) and the male die (2) described above are combined, and the tip of the mandrel (21) of the male die (2) is formed at the end of the extrusion hole (11) of the female die (1). )
The bearing portions (12) and (22) of both sexes are arranged to face each other with an annular forming gap (4) facing. A plate (3) is provided at the rear of the die male mold (2) with its front peripheral edge abutting against the rear peripheral edge of the die male mold, and each molding material introduction space of the plate (3). (33) is combined with each molding material introduction space (24) of the die male mold (2) in a state of being aligned in the circumferential direction. On the rear surface of the male die (2), the bridge part (23), the back pressure utilization part (25), and the mandrel part (21) are provided so as to be retracted in the pushing direction with respect to the peripheral end. When the plate (3) is assembled, a gap (5) is formed between the plate (3) and the bridge portion (23), the back pressure utilizing portion (25), and the mandrel portion (21) of the male die (2). Is formed.

In the die according to the illustrated embodiment, at the time of extrusion, a molding material such as aluminum is diverted by the bridge portion (32) of the plate (3) and passes through the molding material introduction space (33). After passing through the molding material introduction space (24) of 2), they are joined in the welding chamber (6) around the mandrel part (21) and extruded from the molding gap (4).
Therefore, during extrusion, the central baffle (3
Extrusion pressure is applied to the 1) and the bridge part (32) in the extrusion direction as shown by the arrow in FIG. 1, but the bridge part (23) and the back pressure utilization part of the plate (3) and the male die (2) are applied. (2
Since a gap (5) is formed between the plate (3) and the mandrel (21), the deformation of the plate (3) is absorbed by the gap (5), and the pushing pressure applied to the plate (3) is reduced. It does not directly apply to the bridge part (23), the back pressure utilization part (25) and the mandrel part (21) of the male die (2). Also, the mandrel part (21) has a molding gap (4).
Extrusion pressure is applied by the molding material heading toward the die, but at the same time, the molding material filled in the molding material introduction space (24) of the male die (2) and the welding chamber (6) is used to form the male die (2).
The back pressure in the direction opposite to the pushing direction acts on the back pressure receiving surface (25a) and the bridge portion (23) of the back pressure utilization portion (25) in FIG.
The extrusion pressure applied to 1) is canceled, and the mandrel section (2
The deformation of 1) is prevented. Thus, the back pressure receiving surface (25a
In order to prevent the deformation of the mandrel part (21) by using the back pressure applied during extrusion to the maximum extent, the total area of the back pressure receiving surface (25a) should be adjusted to the rear end of the mandrel part (21). It is better to set the cross-sectional area to be almost the same or larger.

As is clear from the above description, the gap (5) between the plate (3) and the bridge portion (23), the back pressure utilizing portion (25) and the mandrel portion (21) of the male die (2). Is provided in order to absorb the deformation of the plate (3) and prevent the influence of the extrusion pressure applied to the plate from exerting on the male die (2). For this,
The size L of the gap (5) is such that even if the plate (3) is deformed, the baffle part (31) has a male die-shaped mandrel part (21).
It is necessary to set so as not to contact the rear surface, and therefore it is preferable to set it to 0.5 mm or more.

Although the embodiment shown in FIGS. 1 to 3 is for a porthole die composed of a combination of a female die (1) and a male die (2), the present invention is limited to a porthole die. Rather, the present invention is applied to the die shown in FIG. 6 and protrudes radially outward on the outer periphery of the rear end of the mandrel at a position between adjacent bridges and extrudes at right angles to the extrusion direction. A back pressure utilization section having a back pressure receiving surface oriented in the direction is formed, and a plate is disposed behind the mandrel section, the bridge section, and the back pressure utilization section, and at least the mandrel section, the back pressure utilization section, and the plate It may be configured such that a gap is provided between them.

[0020]

According to the present invention, the male mandrel portion faces the extrusion hole of the female mold portion, and a molding gap is formed between the inner peripheral bearing portion of the extrusion hole and the outer peripheral bearing portion of the mandrel portion. A plurality of bridges extending radially and having a peripheral end abutting or joined to the female mold part are integrally formed on the outer periphery of the rear end of the part, thereby forming between the adjacent bridge parts. A die in which a material introduction space is formed, and a back that projects radially outward and directs the extrusion direction at right angles to the extrusion direction at a position between adjacent bridge portions on the outer periphery of the rear end of the mandrel portion. A back pressure utilization portion having a pressure receiving surface is formed, and a plate having a molding material introduction space is disposed behind the mandrel portion, the bridge portion, and the back pressure utilization portion, and at least the mandrel portion and the back pressure utilization portion And play The extrusion pressure applied during extrusion is received by the plate so that it is not directly applied to the male die, and the back pressure is applied to the back of the back pressure utilizing part. Since the back pressure in the direction opposite to the pushing direction can be applied to the pressure receiving surface, it is possible to prevent the mandrel portion from being deformed by the pushing pressure. Therefore, deterioration of the dimensional accuracy of the extruded material, which has conventionally occurred due to deformation of the mandrel portion, can be prevented, and an extruded material having excellent dimensional accuracy can be provided.

When the size of the gap is 0.5 mm or more, the deformation of the plate due to the pushing pressure can be reliably prevented from reaching the mandrel, and the deformation of the mandrel can be reliably prevented.

When the area of the back pressure receiving surface in the back pressure utilizing section is set to be substantially the same as or larger than the cross-sectional area of the mandrel section, the back pressure during extrusion can be effectively used, and the mandrel section can be used more and more. A die that can prevent deformation and provide an extruded material with high dimensional accuracy can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of the dice of FIG.

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

FIG. 4 is a longitudinal sectional view showing an example of a conventional die.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a cross-sectional view showing another example of a conventional die.

FIG. 7 is a sectional perspective view of an extruded material extruded using the die of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Die female type (female type part) 2 ... Die male type 3 ... Plate 11 ... Extrusion hole 12 ... Bearing part 21 ... Mandrel part 22 ... Bearing part 23 ... Bridge part 24 ... Molding material introduction space 25 ... Back pressure utilization part 25a ... back pressure receiving surface 3 ... plate 33 ... molding material introduction space 4 ... molding gap 5 ... gap

Claims (3)

(57) [Claims] A male mandrel portion (21) faces an extrusion hole (11) of a female portion (1), and an inner peripheral bearing portion (12) of the extrusion hole (11) and an outer periphery of the mandrel portion (21). A molding gap (4) is formed between the bearings (22), and the outer periphery of the rear end of the mandrel (21) extends radially and abuts the peripheral end with the female mold (1). The plurality of bridge portions (23) joined or joined are integrally formed,
A die in which a molding material introduction space (24) is formed between adjacent bridge portions (23), (23), and an outer peripheral portion of a rear end portion of the mandrel portion (21) has an adjacent bridge portion (23) (23). ), A back pressure receiving surface (25) projecting radially outward and directing the extrusion direction at right angles to the extrusion direction.
a) a back pressure utilization part (25) having
Behind the mandrel part (21), the bridge part (23) and the back pressure utilization part (25), a plate (3) having a molding material introduction space (33) is provided, and at least the mandrel part (21) and the back A deformation preventing die using a back pressure, wherein a gap (5) is provided between the pressure utilization part (25) and the plate (3). 2. The deformation preventing die according to claim 1, wherein the size of the gap (5) is 0.5 mm or more. 3. The back pressure according to claim 1, wherein the area of the back pressure receiving surface (25a) in the back pressure utilization portion (25) is set to be substantially the same as or larger than the cross-sectional area of the mandrel portion (21). Die to prevent deformation due to use.