JP2012035319A - Extrusion dies for forming hollow material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide extrusion dies for forming a hollow material, allowing high-speed extrusion, and capable of lengthening the service life by preventing rupture of a mandrel, even when extrusion-molding a billet made of a high-strength alloy requiring a large extruding force, particularly, a high-strength aluminum alloy such as the so-called 7000 system.SOLUTION: This extrusion dies 10 include a male die 20 for molding an inside shape of the material by extruding the billet B sent from the upstream side to the downstream side, and a female die 30 for molding an outside shape of the material. The male die 20 is constituted of the mandrel 22 and a holder 25 for holding its outer periphery. The mandrel 22 is formed of a material interior-forming part 23, and a bridge part 24 for supporting the material interior forming part 23 and having a tip outer peripheral surface mutually engaging with an inner peripheral part of the holder 25. An engagement surface between the tip outer peripheral surface of the bridge part 24 and the inner peripheral part of the holder 25, is formed as an inclined face which approaches the die center toward the downstream in the extrusion direction.

Description

  The present invention relates to an extrusion die for forming a hollow member for forming a hollow member made of a high-strength alloy, particularly, a high-strength aluminum alloy such as a so-called 7000 type alloy.

In general, extrusion of aluminum alloy or the like is widely used at present because it has a high degree of freedom in cross-sectional shape and is excellent in obtaining a hollow shape material to be extruded.
Particularly in recent years, products obtained by extrusion have been widely used as strength members for structural materials, machine parts, and the like. Therefore, high-strength alloys such as 7075, 7N01, 7003 and so on, such as so-called 7000 series. There is an increasing demand for extruded members made of high-strength aluminum alloys.

  As an example of a conventional extrusion die for forming a hollow material, a hollow material extrusion die made of a so-called spider die in which a male die and a female die are mounted inside a die ring is known (for example, , See Patent Document 1).

As shown in FIG. 17, the spider die 100 disclosed in Patent Document 1 is formed with a male die 101 having a core (mandrel) 110 for shaping the inner shape of the hollow shape member, and the outer shape of the hollow shape member. And a female die 102.
The male mold 101 includes the core 110 and a male ring 112 that holds the core 110. Further, the core 110 is formed by a molding convex portion 113 and a bridge foot 111 that holds the molding convex portion 113.
And the front-end | tip part surrounding side surface 115b of the front-end | tip part 115 of the bridge | bridging leg 111 becomes an inclined surface which expands as it goes to the front side of an extrusion direction. The tip peripheral surface 115 b is fitted with the inner peripheral surface 112 a of the male ring 112.

  The core 110 has a portion for forming the inner shape of the hollow shape at the lower portion thereof, and the outer periphery of the core 110 has, for example, an X shape toward the inner peripheral surface 112a of the male ring 112, that is, The bridge legs 111 extending in all directions are provided. A space surrounded by the four bridge legs 111 and the inner peripheral surface 112a of the male ring 112 is a billet introduction space S made of an aluminum alloy as a material.

The male mold 101 is held by the female mold 102 on the front side in the extrusion direction indicated by the arrow A. In the female mold 102, a lower portion of the core 110 is inserted, and a forming hole portion 106 for forming the outer shape of the hollow shape member is formed. A holding surface 116 that holds the bottom surface of the bridge foot 111 of the male die 101 is formed on the upper surface on the outer peripheral side of the female die 102.
As described above, in the spider die 100 disclosed in Patent Document 1, each bridge foot 111 has an inclined surface that expands as the distal end circumferential surface 115b of the distal end 115 goes to the front side in the extrusion direction. Thus, during the billet extrusion, an axial force acts on each bridge foot 111 and the bending stress acting on each bridge foot 111 is reduced. Therefore, the bending of each bridge foot 111 is suppressed, and the holding state of the core 110 during extrusion is stable.

JP 7-124633 A

  By the way, a high-strength alloy, in particular, a so-called 7000-type high-strength aluminum is used as a material for forming a hollow shape material. When forming an extruded profile having a plurality of hollow parts, the deformation resistance is higher than other alloy types, so the extrusion force increases, and the load on the die tool system is large, so the extrusion speed is increased, It is difficult to improve the life of the die.

  For example, in the hollow material extrusion die 100 disclosed in Patent Document 1, the inner peripheral inclined surface 112a of the male ring 112 and the distal end peripheral surface 115b of the bridge foot 111 are press-fitted, and the bridge foot 111 is extruded. Compressive stress in a direction orthogonal to the direction is generated, and this compressive stress and the pushing force applied to the upper surface of each bridge foot 111 when the extrusion process is performed, that is, the extrusion direction leading side generated in the forming convex portion 113 This is intended to cancel out the tensile force that is pulled to the bottom, and thus to prevent breakage of the bridge foot 111 and consequently breakage of the core 110.

However, in the extrusion die 100 described above, the distal end portion 115 of the bridge foot 111 is inclined in a direction spreading toward the front side in the extrusion direction, so that the distal end portion 115 of the bridge foot 111 is on the holding surface 116 of the female die 102. The distance L between the base end portion P1 held at this point and the intersection between the bridge foot 111 and the molding convex portion 113, that is, the action point P2 that may be broken by a tensile force, is increased, and the moment is increased.
For this reason, when a pushing force is applied to the core 100, a large load is applied to the action point P2, and the bridge foot 111 is broken.

In order to solve this problem, the size of the bridge foot 111 is increased to increase the strength of the bridge foot 111, or the distance L between the base end portion P1 and the action point P2 is decreased to reduce the moment. Can be considered.
However, when the dimensions of the bridge 111 are increased, the billet introduction space S for guiding and accommodating the billet is reduced, and the set amount of the billet cannot be secured. In order to secure the set amount of the billet, it is necessary to increase the inner diameter portion of the male ring 112, and as a result, the die becomes larger and the distance L becomes longer, so that the moment cannot be reduced.
Further, when the distance L between the base end portion P1 and the action point P2 is reduced, the space between the male ring 112 and each bridge foot 111, that is, the billet introduction space S is reduced, and the billet extrusion amount is reduced. Problems such as reduction occur, and there is a limit to reducing the distance L naturally.

  As described above, in the spider die 100 that tries to solve the problem by canceling between the compressive stress and the tensile stress, the bridge foot 111 and the core 110 may be broken, so that the life of the die can be extended. There is a limit to the plan.

  In order to solve the above problems, in the present invention, even when extruding a billet (extruded material) made of a high-strength alloy having a large extrusion processing force, particularly a high-strength aluminum alloy such as a so-called 7000 series, high-speed extrusion is possible. Another object of the present invention is to provide an extrusion die for forming a hollow shape that can prevent the mandrel from being broken and extend its life.

  In order to achieve the above object, the extrusion die for forming a hollow shape material of the present invention is a male die for extruding a billet made of an aluminum alloy sent from the upstream side to the downstream side to shape the inner shape of the hollow shape material, An extrusion die for forming a hollow member having a female die for forming the outer shape of the hollow member, wherein the male die, a mandrel for forming the inner shape, and the mandrel are partially held from the outside And a plurality of bridges projecting from the outer periphery of the profile inner molded portion to the inner peripheral surface side of the holder. A bridge contact engagement surface formed on the inner peripheral surface of the holder and in contact with and engaged with the outer peripheral surface of the tip of each bridge. And each of the above Tsu downstream of said extrusion direction and a tip outer peripheral surface of di is characterized in that an inclined surface as approaching the die center.

Since the extrusion die for forming a hollow shape material of the present invention is configured as described above, a bridge contact member formed on the outer peripheral surface of the plurality of bridges constituting the bridge portion of the mandrel and the inner peripheral surface of the holder. Since the mating surface is formed on an inclined surface that is inclined so as to approach the center of the die along the extrusion direction, the base end portion of each of the plurality of bridges on the support surface of the holder, and the inner shape of the profile from the base end portion The distance to the action point in the direction orthogonal to the extrusion direction at the part can be reduced.
For this reason, the moment generated at the action point of the profile inner molded portion can be reduced, so that the strength of each of the plurality of bridges can be increased, thereby preventing breakage of the bridge portion of the mandrel. As a result, even when a billet (extrusion material) made of a high-strength alloy having a large extrusion processing force, particularly a high-strength aluminum alloy such as the so-called 7000 series, is extruded, high-speed extrusion can be achieved and the life of the die can be extended. become.
Further, the outer peripheral surface of each bridge end and the bridge contact engagement surface formed on the inner peripheral surface of the holder are inclined so that the downstream side in the pushing direction approaches the center of the die. The lower end of the surface extends toward the die center side, and most of the lower end surface of the holder is held by a female holding surface. Therefore, since the bridge portion composed of the holder and each of the plurality of bridges is stably held, a stable hollow shape can be formed.

1 is an overall plan view showing one embodiment of an extrusion die for forming a hollow shape according to the present invention. It is a longitudinal cross-sectional view along the II-II line in FIG. It is a longitudinal cross-sectional view which shows the detail of the male type | mold of the said embodiment. It is a longitudinal cross-sectional view along the IV-IV line in FIG. It is a whole top view which shows the mandrel of the said embodiment. It is a longitudinal cross-sectional view along the VI-VI line of FIG. It is a longitudinal cross-sectional view along the VII-VII line of FIG. FIG. 6 is a view taken along arrow VIII in FIG. 5. It is a whole top view which shows the holder of the said embodiment. It is a longitudinal cross-sectional view along the XX line of FIG. It is a whole top view which shows the female type | mold of the said embodiment. It is a longitudinal cross-sectional view along the XII-XII line of FIG. It is a perspective view which shows the cross-shaped square-shaped hollow shape shape | molded by the extrusion die for hollow shape material shaping | molding of the said embodiment. It is a perspective view which shows the hollow shape material of the cross-sectional opening shape shape | molded with the extrusion die for hollow shape material shaping | molding of the said embodiment. It is a longitudinal cross-sectional view which shows the male deformation | transformation form of the extrusion die for hollow shape shaping | molding which concerns on this invention. FIG. 16 is a longitudinal cross-sectional view of the cross section taken along line XVI-XVI in FIG. It is a longitudinal cross-sectional view which shows the conventional die for hollow material extrusion.

  Below, with reference to FIGS. 1-12, one Embodiment of the extrusion die (henceforth an extrusion die) 10 for hollow shape molding of this invention is described.

  The extrusion die 10 of the present embodiment forms a hollow shape made of a high-strength alloy, in particular, a high-strength aluminum alloy such as a so-called 7000 series. In the extrusion die 10 of the present embodiment, as shown in FIG. The hollow profile 1 having a cross-sectional shape is formed.

As shown in FIG. 2, the extrusion die 10 includes a male die 20 for extruding a billet B made of an aluminum alloy sent from the upstream side in the extrusion direction to the downstream side to form the inner shape of the hollow shape member 1, and a hollow die. A female die 30 for forming the outer shape of the profile 1 and a back die 40 for holding the female die 30 are provided.
The billet B is accommodated in a billet extrusion device 60 composed of a chamber or the like disposed on the upstream side of the male mold 20 and is configured to be extruded by the billet extrusion device 60.

The male mold 20, the female mold 30, and the back die 40 are integrally connected.
That is, after the male mold 20 and the female mold 30 are positioned by, for example, two positioning pins 45 as shown in FIGS. 1 and 2, the male mold 20, the female mold 30, and the back die 40 are For example, it is connected and fixed by two connecting bolts 46.

  As shown in detail in FIG. 3, the male mold 20 includes a mandrel 22 that molds the inner shape of the hollow shape member 1 and a holder 25 that partially holds the outer periphery of the mandrel 22. 25 and the mandrel 22 are integrated by press-fitting, for example.

The mandrel 22 has a profile inner molded portion 23 corresponding to the inner shape of the hollow profile 1 and a plurality of bridges that support the profile inner molded portion 23 and extend from the profile inner molded portion 23 in substantially four directions. In other words, the bridge portion 24 includes a first bridge 24a, a second bridge 24b, a third bridge 24c, and a fourth bridge 24d.
The four outer peripheral surfaces 24C of the first bridge 24a, the second bridge 24b, the third bridge 24c, and the fourth bridge 24d are engaged with the bridge abutment of the bridge holding portion 26 in the holder 25. It partially engages with the bridge seating surface 26A, which is a surface.
The engagement surfaces of the outer peripheral surface 24C of the first bridge 24a, the second bridge 24b, the third bridge 24c, and the fourth bridge 24d and the bridge seating surface 26A of the holder 25 are in the pushing direction. It is formed in the inclined surface which approaches the center of die | dye toward the downstream side from the upstream.

  Here, as shown in FIG. 1, when the mandrel 22 of the male mold 20 and the holder 25 are assembled together, the profile member inner molding portion 23, the first bridge 24 a, and the second bridge constituting the mandrel 22 are assembled. The upper surfaces of the bridge 24b, the third bridge 24c, and the fourth bridge 24d are set in the shape of a recess that is retracted from the upper end surface (seal surface 25B) of the holder 25 to the downstream side in the pushing direction of a predetermined dimension. Billet introduction spaces S and S1 are formed by these hollow portions and the space between the four bridge portions 24.

As shown in FIG. 5, the bridge portion 24 extends from the upper surface portion 23A of the profile member inner molding portion 23 in substantially four directions as described above, and includes a first bridge 24a, a second bridge 24b, and a third bridge 24c. The fourth bridge 24d is formed so that the planar shape is substantially X-shaped.
The first to fourth bridges 24a to 24d include an inclined surface 24B (see FIG. 3) that decreases from the upper surface portion 23A toward the distal end portion 24A, and the distal end of the inclined surface 24B, that is, the distal end portion 24A. The bridge tip outer peripheral surface 24 </ b> C that is continuous with the bridge is provided.
The bridge tip outer peripheral surface 24C engages with and is held by the bridge seating surface 26A of the holder 25 described in detail later.

  The inclined surface 24B has a shape that expands from its upper end toward the bridge seating surface 26A of the holder 25. Then, as shown in FIG. 4, the width is formed on the outer peripheral surface 24C of the bridge tip, and the outer peripheral surface 24C of the bridge tip abuts on and is held by the bridge seating surface 26A, as shown in FIG. Furthermore, the base end portion P1 is reached while inclining in a direction approaching the center portion of the die.

Here, in the extrusion die 10 of the type as in the present embodiment, the contact between the first to fourth bridges 24a to 24d and the holder 25 becomes strong on the downstream side of the bridge seating surface 26A, and the compressive stress is very high. Tend to be higher. In order to reduce the compressive stress in this portion, the portion that abuts on the bridge seating surface 26 </ b> A on the left and right sides as shown in FIGS. It was set as the shape which provided the extended part 24E of the expanded triangular shape (refer also FIG. 7, 8).
The extended portion 24E comes into contact with an expanded portion 26C formed on the downstream side of the bridge seating surface 26A. For this reason, the contact area between the first to fourth bridges 24a to 24d and the bridge seating surface 26A increases by the amount of the expanded portion 24E, so that the compressive stress at that portion can be reduced.

  As described above, the bridge tip outer peripheral surface 24C is engaged with the bridge seating surface 26A of the holder 25 over a predetermined distance along the pushing direction, and from the terminal portion to the tip of the molding inner molding portion 23 is formed. It is a billet guide portion 24G (see FIG. 6) having a gentle arc shape toward 23B.

The inner molding protrusion 23B is formed to protrude slightly outward from the end of the billet guide hole 24F. And the space | interval of the predetermined dimension set between this inner side shaping | molding protrusion part 23B and the outer side shaping | molding opening part 30A of the said female die 30 becomes the hole 50 for shape forming (refer FIG. 7, FIG. 8). ).
A step is formed at the downstream end of the flow of the inner molding protrusion 23B, and this step is a relief portion 50A (see FIG. 6) having an inclined shape that becomes wider in the downstream direction of the flow.

  As shown in FIGS. 7 and 8, the end of the profile inner molding portion 23 on the downstream side in the extrusion direction has a hollow shape with a cross-sectional shape as shown in virtual images in FIGS. 13, 7, and 8, respectively. A first inner piece portion 23B, a second inner piece portion 23C, and a third inner piece portion 23D that form the three spaces 1S, 1S, and 1S of the profile 1 are formed.

  Here, as shown in FIGS. 13, 7, and 8, the hollow shape member 1 having a cross-sectional shape has a pair of long side walls 1 </ b> A and 1 </ b> A and longitudinal ends of the long side walls 1 </ b> A and 1 </ b> A. It has a shape having short side walls 1B and 1B that connect the parts, and two partition walls 1C and 1C that are equally disposed between the short side walls 1B and 1B.

  The thickness dimensions of the two partition walls 1C and 1C are set to be thinner than the thickness dimensions of the long side walls 1A and 1A and the short side walls 1B and 1B. However, the thickness dimensions of the partition walls 1C, the long side walls 1A, and the short side walls 1B may be the same, and can be freely set according to the specifications of the hollow shape member 1.

The first inner piece portion 23B, the second inner piece portion 23C, and the third inner piece portion 23D are each formed in a substantially quadrangular prism shape, and as described above, on the downstream side in the extrusion direction of the shape member inner molding portion 23. Is provided at the end.
In each of the pieces 23B, 23C, and 23D, on the upstream side in the pushing direction, strip-like projection frames 23E that protrude outward from the respective outer circumferences are provided so as to wrap around the respective outer circumferences.

The projection frames 23E at the outer periphery of the first inner piece portion 23B and the third inner piece portion 23D and the projection frames 23E at the outer periphery of the second inner piece portion 23C are the openings for the outer shape of the female die 30. 30B is opposed to each other, and each gap constitutes a shape forming hole 50 for forming the long side walls 1A, 1A and the short side walls 1B, 1B.
The long side walls 1A and 1A and the short side walls 1B and 1B of the hollow shape 1 are formed by the billet B extruded from the shape forming hole 50.

Further, the gap between the protruding frame 23E of the first inner piece 23B and the protruding frame 23E of the second inner piece 23C, and the protruding frame 23E of the second inner piece 23C and the third inner piece 23D. A gap with the projection frame 23E constitutes a shape forming hole 51 for forming the partition walls 1C and 1C.
The partition walls 1 </ b> C and 1 </ b> C of the hollow shape member 1 are formed by the billet B extruded from the shape forming hole portion 51.

In the gap between the projection frame 23E of the first inner piece portion 23B and the projection frame 23E of the second inner piece portion 23C, the gap between the projection frame 23E of the second inner piece portion 23C and the projection frame 23E of the third inner piece portion 23D. The billet guide holes 24F communicate with each other.
The billet guide hole 24F is formed along a line direction connecting the first bridge 24a and the second bridge 24b, and the third bridge 24c and the fourth bridge 24d, as indicated by a dotted line in FIG. As shown in FIGS. 6 and 7, it is formed in a substantially semicircular tunnel shape.

The billet guide hole 24F is pressed and guided by the billet B from the billet introduction spaces S and S1 as indicated by an arrow n and is extruded through the shape forming hole 51. It is like that.
Further, the billet B is formed in the gap between the projection frame 23E of the first inner piece portion 23B and the third inner piece portion 23D and the profile shape opening 30B of the female die 30, that is, in the profile formation hole portion 50. It is pressed and guided from the introduction spaces S and S1 as indicated by the arrow m, and is extruded through the shape forming hole 50.

  As shown in FIGS. 9 and 10, the holder 25 is formed in an overall disk shape having a predetermined thickness, and a circular billet introduction opening 25 </ b> A is formed on an end face on the upstream side in the extrusion direction. Is formed.

In the holder 25, a bridge holding portion 26 is provided on the downstream side in the extrusion direction of the billet introduction opening 25 </ b> A so as to sandwich and hold the bridge portion 24 from the outer periphery thereof.
That is, as shown in FIG. 9, the bridge holding portions 26 are provided at four locations corresponding to the first to fourth bridges 24 a to 24 d arranged in a substantially X shape. Each bridge holding portion 26 has the bridge receiving surface 26A for holding the bridge tip outer peripheral surface 24C of the first to fourth bridges 24a to 24d of the mandrel 22, as described above. .

  These bridge seating surfaces 26 </ b> A are adapted to engage with the bridge tip outer peripheral surface 24 </ b> C of the bridge portion 24. That is, as shown in FIG. 10, the bridge seating surface 26A is formed to be inclined so as to approach the die center C from the upstream end portion 26F in the extrusion direction toward the downstream side in the extrusion direction of the billet B. It is the base end portion P1 in the bridge seating surface 26A.

The base end portion P1 of the bridge seating surface 26A is continuous with the escape portion 26D that is expanded outward from the position where the engagement with the bridge tip outer peripheral surface 24C is released, that is, in a direction away from the die center C. Then, as shown in FIG. 7, the relief portion 26D and the billet guide portion 24G of the bridge portion 24 form a billet communication path S3 having a semicircular cross section, and the billet communication path S3 is It communicates with billet introduction spaces S, S1.
Here, the inclination angle α ° between the bridge seating surface 26A and the bridge outer peripheral surface 24C is set in a range of 55 ° to 60 °, for example. However, it is not limited to this angle.
Note that the end surface of the holder 25 on the upstream side in the billet extrusion direction is a seal surface 25 </ b> B for contacting the billet extrusion device 60.

As shown in detail in FIGS. 9 and 10, the bridge seating surface of the holder 25 is between the billet introduction opening 25A of the holder 25 and the upstream end portion 26F in the pushing direction of the bridge seating surface 26A. A stopper portion 26B is provided to prevent the first to fourth bridges 24a to 24d and thus the mandrel 22 from coming off from 26A.
That is, the stopper portion 26B is formed so as to protrude from the billet introduction opening 25A to the center C side of the die by a predetermined dimension and to extend a predetermined dimension downstream in the extrusion direction. Further, the front side of the stopper portion 26B on the downstream side in the pushing direction is formed to be recessed outside the die, and the R portion thereof serves as the upstream end portion 26F of the bridge seat surface 26A.

As shown in FIGS. 11 and 12, the upper surface of the female die 30 is provided with a holder receiving surface 30A having a recessed central portion, and the lower surface 25B of the holder 25 abuts on the holder receiving surface 30A. Thus, the holder 25 is held.
In the holder receiving surface 30A, a profile outer shape opening 30B is formed at the center. The profile outer shape opening 30 </ b> B forms the outer shape of the hollow profile 1 (see FIG. 13) having a cross-sectional shape that is a molded product described below.

  As shown in FIG. 12, the profile outer shape opening 30 </ b> B is formed by a straight portion having a slight size and a relief hole 30 </ b> C that expands from the straight portion toward the outer periphery of the female die 30.

FIG. 13 shows the hollow shape member 1 extruded by the die 10 configured as described above.
That is, as shown in FIG. 13, the hollow shape member 1 connects both ends of a pair of long side portions 1A with short side portions 1B, and two partition wall portions 1C between the short side portions 1B. Is formed between the pair of long side portions 1A and has a cross-sectional shape having three spaces 1S, 1S, 1S therein.
And the hollow shape material 1 having such a cross-sectional shape is continuously extruded from the shape forming hole 50 of the extrusion die 10 in accordance with the supply amount of the billet B. .

Next, a method for forming the hollow member 1 using the extrusion die 10 having the above-described configuration will be described.
When the billet B is extruded with respect to the male mold 20 by the billet extrusion device 60 disposed on the upstream side in the extrusion direction of the billet B, the billet B is first inserted into the male 25 from the billet introduction opening 25A. It is introduced into a billet introduction space S formed by a gap between the mandrel 22 and the holder 25 of the mold 20.

The billet B introduced into the billet introduction space S passes through the first to fourth bridges 24a to 24d arranged in a substantially X shape and the side surfaces of the profile inner molded portion 23, and the profile inner molded portion 23 and It is guided to the shape forming hole 50 formed between the female die 30 and the shape outer shape opening 30 </ b> B, and is extruded from the shape forming hole 50.
The extruded hollow profile 1 is fed from a profile feed hole 40A formed in the back die 30, and then held by a holding mechanism (not shown) and carried into a predetermined stockyard or the like. .

Since the extrusion die 10 of the present embodiment is configured as described above, the following effects can be obtained.
(1) The engagement surface of the outer peripheral surface 24C of the first to fourth bridges 24a to 24d of the bridge portion 24 constituting the mandrel 22 and the bridge seating surface 26A of the bridge holding portion 26 faces the downstream side in the pushing direction. Therefore, the base end portion P1 of the bridge seating surface 26A of the holder 25 and the direction perpendicular to the extrusion direction from the base end portion P1 to the profile member inner forming portion 23 are formed. The distance L1 to the point of action P2 can be reduced. Therefore, the moment generated at the action point P2 of the shape member inner molding portion 23 can be reduced, and as a result, the strength of the first to fourth bridges 24a to 24d can be increased. Breakage of the four bridges 24a to 24d can be prevented. As a result, even when a billet B made of a high-strength alloy having a large extrusion processing force, particularly, a high-strength aluminum alloy such as a so-called 7000 series is extruded, high-speed extrusion can be achieved and the life of the die can be extended.

(2) An inclined surface such that the engagement surface between the distal end outer peripheral surface 24C of the first to fourth bridges 24a to 24d and the bridge receiving surface 26A of the bridge holding portion 26 approaches the die center toward the downstream side in the pushing direction. Therefore, the lower end surface of the holder 25 extends toward the die center side. Therefore, most of the lower end surface of the holder 25 is held by the holding surface 30A of the female die 30, so that the holder 25 and the first to fourth bridges 24a to 24d are stably held, and as a result, a stable hollow shape The material 1 can be molded.

(3) Since a portion of the first to fourth bridges 24a to 24d in the vicinity of the base end portion P1 is provided with a triangular extension portion 24E in which a portion that abuts on the extension portion 26C of the bridge seating surface 26A extends left and right. The contact area between the first to fourth bridges 24a to 24d and the bridge seating surface 26A is increased by the extension portion 24E. As a result, it is possible to reduce the compressive stress in the entire first to fourth bridges 24a to 24d to which the expanded portion 24E is added, so that breakage of the first to fourth bridges 24a to 24d can be prevented. Thereby, even when billet B made of a high-strength aluminum alloy such as a so-called 7000 series is extruded, high-speed extrusion can be performed and the life of the die can be extended.

(4) Since the bridge portion stopper portion 26 </ b> B is formed on the upstream side of the bridge receiving surface 26 </ b> A of the bridge holding portion 26 in the holder 25 so as to protrude toward the center portion in the radial direction of the holder 25. It is possible to prevent the 24 from coming out of the holder 25, thereby enabling stable extrusion molding.

  While the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention. Further, the invention of the present application includes a combination of part or all of the configurations of the above-described embodiments as appropriate.

  For example, in the above-described embodiment, the hollow member 1 formed by the extrusion die 10 is a hollow member having a cross-sectional shape, but the present invention is not limited thereto. It can also be used when molding a hollow member 2 having a cross-sectional shape as shown in FIG.

In this case, first, instead of the first inner piece portion 23B, the second inner piece portion 23C, and the third inner piece portion 23D of the shape member inner molding portion 23 in the mandrel 22 of the above-described embodiment, In order to form the internal space 2 </ b> S of the hollow shape member 2, one substantially square columnar piece portion is provided at the end portion of the shape member inner molding portion.
Then, instead of the shape member outer shape opening 30B of the female die 30, a substantially rectangular shape member outer shape opening corresponding to one piece of the substantially square pillar shape may be provided in the female shape.
At this time, the engagement state and the inclination angle between the outer peripheral surface of the bridge of the mandrel and the bridge seating surface of the holder may be the same as those in the configuration for the eye-shaped hollow shape member 1 as described above. Since it can be used as it is, it is possible to extrude a plurality of types of hollow shapes having different cross-sectional shapes with a small number of members.

  In the above embodiment, the bridge portion 24 including the first bridge 24 a, the second bridge 24 b, the third bridge 24 c, and the fourth bridge 24 d is formed integrally with the shape member inner molding portion 23. The mandrel 22 is configured, and the outer peripheral surfaces 24C of the first to fourth bridges 24a to 24d are supported by the bridge seating surface 26A of the holder 25. 15. It is good also as a structure as shown in FIG.

  In the mandrel 72 of this modification, a bridge receiving seat surface 76A, which is a bridge contact engagement surface, protrudes from the inner peripheral surface 25D of the holder 25 to the center C side of the mandrel 72, and accordingly, the bridge portion 74 The only difference is that the length of the outer peripheral surface 74C of the tip of the first bridge 74a and the like is shortened, and the other configuration is exactly the same as the mandrel 22 of the above embodiment. Therefore, in the modification shown in FIG. 15 and FIG. 16, the same members and the same configurations as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The mandrel 72 includes a profile inner molded portion 73 corresponding to the profile inner molded portion 23, and the first bridge 24a extending from the outer periphery of the profile inner molded portion 73 toward the inner peripheral surface 25D of the holder 25. And a bridge portion 74 composed of a first bridge 74a and the like.

The bridge unit 74 includes a first bridge 74a, a second bridge, a third bridge, and a fourth bridge (not shown).
As described above, these first bridges 74a and the like have a distance from the center C of the male die 20 to the outer peripheral end surface 24C of the first bridge portion 74a and the like from the first bridge portion 24a of the above embodiment. Is also shorter.
The first bridge 74a and the like are formed with an inclined surface 74B that is lowered from one end of the upper surface 73A of the profile inner molding portion 73 toward the distal end portion 74A side of the first bridge 74a.

On the other hand, a bridge holding portion 76 corresponding to the bridge holding portion 26 is provided on the inner peripheral portion of the holder 25.
The bridge holding portion 76 includes a bridge receiving seat surface 76A corresponding to the bridge receiving seat surface 26A of the embodiment. As shown in FIG. 16, the bridge receiving seat surface 76 </ b> A is configured by a projecting surface that protrudes from the inner peripheral surface 25 </ b> D of the holder 25 toward the center C side of the male mold 20 by a predetermined dimension. The bridge receiving seat surface 76A is in contact with and engaged with the outer peripheral surface 24C of the tip such as the first bridge portion 74a.

That is, in this modified embodiment, the first bridge portion 74a having a short length and the like and the bridge receiving seat surface 76A protruding by a predetermined dimension are configured to correspond to the first bridge portion 24a of the embodiment. Will be.
The bridge receiving seat surface 76A and the outer peripheral surface 24C such as the first bridge portion 74a are in contact with each other and are inclined so that the downstream side in the village pushing direction approaches the die center.

Further, an escape portion 76D corresponding to the escape portion 26D of the above embodiment is formed at the lower end of the bridge receiving seat surface 76A. Furthermore, a stopper portion 76B corresponding to the stopper portion 26B of the above embodiment is formed on the upstream side in the extrusion direction of the bridge receiving seat surface 76A.
Further, an extended portion 74E corresponding to the extended portion 24E of the above-described embodiment is provided on the outer peripheral surface 24C of the tip such as the first bridge portion 74a.

  And according to such a deformation | transformation form, since the lower end of 76 A of bridge receiving seat surfaces protrudes in the center C side of the holder 25 and by extension, the male type | mold 20, the base end part P1 of the lower end of 76 A of bridge receiving seats and The distance L2 between the first bridge portion 74a and other action points P2, which may break due to the tensile force of the outer peripheral surface 24C of the tip, can be made shorter than the distance L1 in the above embodiment. Thereby, the moment which arises in the action point P2 of the shape member inner side shaping | molding part 73 can be made smaller, and also fracture | rupture of the 1st bridge | bridging 24a etc. can be prevented. As a result, even when a billet B made of a high-strength alloy having a large extrusion processing force, particularly, a high-strength aluminum alloy such as a so-called 7000 series is extruded, high-speed extrusion can be achieved and the life of the die can be extended.

  The extrusion die of the present invention is used when molding a hollow material made of a high-strength alloy, particularly a high-strength aluminum alloy such as a so-called 7000 series.

DESCRIPTION OF SYMBOLS 1 Cross-shaped hollow shape 10 Extrusion die | dye for hollow shape shaping | molding 20 Male type | mold 22 Mandrel 23 Profile shape inside shaping | molding part 23B Inner shaping | molding projection part 24 Bridge parts 24a-24d First to fourth bridge 24C Outer peripheral surface 24E Expansion portion 25 Holder 26 Bridge holding portion 26A Bridge seating surface 26B which is a bridge contact engagement surface Bridge portion stopper portion 30 Female die 30B Shape shape outer shape opening 50 Shape shape formation hole portion 51 Shape formation Hole portion 72 Mandrel 73 Profile inner molding portion 73B Inner molding protrusion 74 Bridge portion 74a First bridge 74C Bridge tip outer peripheral surface 76 Bridge holding portion 76A Bridge seating surface 76B which is a bridge contact engagement surface For bridge portion Stopper

Claims (4)

A hollow member comprising a male die for forming the inner shape of the hollow shape member by extruding a billet made of an aluminum alloy sent from the upstream side to the downstream side, and a female die for shaping the outer shape of the hollow shape member. An extrusion die for molding,
The male mold is composed of a mandrel that molds the inner shape, and a holder that partially holds the mandrel from the outside,
The mandrel is formed by a profile inner molding portion corresponding to the inner shape of the hollow profile, and a bridge portion including a plurality of bridges protruding from the outer periphery of the profile inner molding portion to the inner peripheral surface side of the holder. And
Provided on the inner peripheral surface of the holder is a bridge abutting engagement surface that abuts and engages with the outer peripheral surface of the end of each bridge,
An extrusion die for forming a hollow shape, characterized in that each of the bridge contact engagement surfaces and the outer peripheral surface of the tip of each bridge are inclined surfaces such that the downstream side in the extrusion direction approaches the die center. In the extrusion die for hollow shape molding according to claim 1,
An extrusion die for forming a hollow shape member, wherein each bridge abutting engagement surface is constituted by a protruding surface protruding from an inner peripheral surface of the holder toward the tip end surface of each bridge. In the extrusion die for forming a hollow material according to claim 1 or 2,
An extrusion die for forming a hollow shape member, wherein an extended portion that swells to the left and right from the end portion is provided at the downstream end portion of the outer peripheral surface of each bridge. In the extrusion die for hollow shape molding according to any one of claims 1 to 3,
An extrusion die for forming a hollow shape member, wherein a bridge portion stopper portion is provided on the upstream side of the inner peripheral portion of the holder so as to protrude toward the center portion in the radial direction of the holder.

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