JP2002045913A - Extruding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve wear resistance and to suppress chipping in the projection part as small as possible. SOLUTION: A core 4 has bar-shaped projecting bodies 5 of the projection parts consisting of the projection parts 3a and the base 3b of the projections which are extended to the upstream side with the direction of a base stock flow as a reference. These bar-shaped bodies of the projection parts are arranged in parallel to each other in a plurality of grooves 12 provided on the main body of a male die, fit and fixed thereto. A groove 7 which is placed orthogonally to the length direction is formed in the base part 3b of the projection of each bar-shaped body 5 of the projection part and a common stopper 8 for controlling the movement in the length direction of the bar-shaped body is engaged with those grooves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion die suitable for use in extruding a flat multi-hole tube used in, for example, various aluminum heat exchangers.

[0002]

2. Description of the Related Art As is well known, extrusion of various metals is used in manufacturing various electrical devices and mechanical parts such as automobiles. Among them, especially in manufacturing various aluminum heat exchange tubes used for heat exchangers such as evaporators for car air conditioners, condensers, radiators, etc. Processing is widely used,
When such an extrusion process is actually performed, an extrusion die is used.

FIGS. 17 to 21 show an example of a conventionally known extrusion die (see Japanese Patent Application Laid-Open No. Hei 7-124634). The extrusion die includes a male die 31 (see FIG. 17) having a substantially rectangular plate shape and a female die 41 (see FIGS. 18 and 19) having a substantially cylindrical shape.

As shown in FIG. 17, a plate-shaped male die 31 having a predetermined plate thickness is made of, for example, high-speed steel, hot die steel, or the like. A part 33 is formed. At the center of the step portion 33, a protruding portion 34 is formed, which protrudes further in a comb-like shape. Also, on both side surfaces 35 of the male die 31 sandwiching the end surface 32, formed are flow-in portions 36 whose plate thickness gradually decreases toward the protruding portions 34, respectively. And this inflow section 36
Between the side surfaces 35 located on both sides of the plate-shaped fitting portions 37, 37 having a uniform plate thickness.

On the other hand, as shown in FIGS. 18 and 19, the female die 41 is composed of a main body 42 made of die steel and an insert 43 made of high-speed steel or cemented carbide which is harder than the main body 42. It is configured. The main body 42 is a member having a substantially cylindrical shape in appearance, and the male die 3
A groove 45 is formed in the end face 44 facing the first part 1 and has a predetermined width and penetrates in the radial direction. A rectangular recess 47 is formed at the center of the bottom surface 46 of the groove 45, and the insert 43 is fitted in the recess 47.

The insert 43 is formed in a rectangular plate shape which is fitted in the recess 47 and whose upper surface is flush with the bottom surface 46 of the groove 45. As shown in FIG. 19, a through hole 48 extending in a direction orthogonal to the extending direction of the groove 45 is formed. This through hole 48
Is located on the upper surface side of the insert 43, into which the protruding portion 34 is inserted, and between the protruding portion 34, an oblong mold hole 49 for extruding a material (a billet) such as aluminum into a predetermined shape. And the opening width of the mold hole 4
9 and a discharge hole 50 formed on the lower surface of the insert 43. And this nest 43
Is fitted and fixed in the recess 47 by shrink fitting.

On the end faces 44 located on both sides of the groove 45 of the main body 42, concave grooves 51, 51 which are shallower than the groove 45 and extend in a direction perpendicular to the groove 45 are formed. On the other hand, the other end surface 52 of the main body 42 has a first hole 53 through which one end communicates with the through hole 48 and a molded product is discharged by opening the other end to the other end 52. A second hole 54 is formed in a direction perpendicular to the first hole 53, one end of which is open on the bottom surface of the recess 47, and the other end of which is open on the other end 52. I have.

In this die, the projection 34 of the male die 31 is positioned in the mold hole 49 of the female die 41,
The fitting portion 37 of the male die 31 is fitted into the concave portion 51 of the female die 41, and the male die 31
The step 33 of the female die 41 is fitted between the grooves 45 of the female die 41 to be used integrally.

The male dice 31 and the female dice 4 having the above constructions
1 is inserted into and fixed in the through hole of the die holder, which serves as the material inflow path, and is made of aluminum or the like inserted in the hole of the container connected to the through hole that serves as the material inflow path. The material (billet) is pressed by a pressure plate (stem) so as to flow toward the die. At this time, the extruded billet is moved from between the both side surfaces 35 and 35 of the male die 31 and the inner wall surface of the through-hole of the die holder to the gap between the protrusion 34 of the male die 31 and the mold hole 49 of the female die 41. And flows through the gap between the mold hole 49 and the projection 34, for example, a flat multi-hole tube Ca as shown in FIG. 13 is extruded.

[0010]

When the billet flows into the material flow path in the extrusion die described above, the die shown in FIG.
The material in the high-pressure and high-temperature state flows into the projection 34 of the male die 31 shown in (1), and an excessive pressure is applied, and the abrasion of the projection 34 proceeds rapidly. For this reason, frequent replacement of the male die 31 is required, which causes a problem that the cost of the mold rises. This problem is particularly noticeable when the flat multi-hole tube Ca of FIG. 20 having a large number of holes is formed, because the thickness of the projection 34 of the male die 31 used becomes thin and the resistance to abrasion is weakened. appear.

In order to deal with such a problem, recently,
As shown by a two-dot chain line in FIG. 17, the core portion including the protruding portion 34 at the tip of the male die 31 is separately provided.
A has been developed in which a is made of a cemented carbide that is resistant to wear, and the other part of the male die body 31b is made of ordinary die steel (for example, see Japanese Patent Application Laid-Open No. 9-155438).

By the way, as described above, the male die body 3
1b and the core 31a are separated from each other, and the core 31a is made of a cemented carbide or high-speed steel having excellent wear resistance.
As shown in FIG. 1, the portion where the plurality of projections 34 at the tip of the core 31a are formed requires high hardness of the material itself and requires fine and high-precision processing. At present, machining can only be performed by electric discharge machining or wire electric discharge machining.

When ordinary electric discharge machining or wire electric discharge machining using an electrode plate is employed, since the core 31a is made of a cemented carbide or high-speed steel having a high hardness, the wear resistance is increased to some extent. However, there is a disadvantage that the protruding portions 34 are likely to be lost.

The present inventors have observed the projections 34 of the core 31a processed by ordinary electric discharge machining or wire electric discharge machining in detail using a scanning electron microscope or the like. In addition to the formation of the layer (irregular layer), it has been found that phenomena such as chipping or minute falling off of the material have occurred at the edge of the protrusion 34, which is one of the causes that the protrusion 34 is likely to be damaged. I thought it was one.

That is, in the electric discharge machining, electrodes (plates, wires, etc.) are arranged with an appropriate gap from the object to be processed, a discharge is generated between the electrode and the work, and the material near the discharge point is melted and evaporated. , Which is blown off by the explosion pressure caused by electric discharge, and the work surface of the work becomes high temperature. The edge portion of the portion 34 is intensively processed, and as a result, the protrusion 3
It was thought that this was because the strength of No. 4 was reduced.

The present invention has been made in view of the above circumstances, and has as its object the object of the present invention is to provide excellent wear resistance.
In addition, it is an object of the present invention to provide an extrusion pressing die capable of minimizing the phenomenon of protrusions being lost.

[0017]

The present invention has the following features in order to solve the above-mentioned problems. That is,
The invention according to claim 1 includes a male die having a plurality of projections arranged at a predetermined interval from each other, and a female die having a mold hole into which the projections are inserted, and these male and female dies are fitted to each other. The fitting portion is fitted and connected to the extruder, and the material is extruded from a gap formed between the mold hole and the protruding portion, whereby the flat multi-hole tube is extruded. In the extrusion die, the male die includes a male die body and a core that is fitted and fixed to substantially the center of the male die body and has the plurality of protrusions.
Projecting rods each consisting of the projecting portion and a projecting base extending from the projecting portion to the upstream side with respect to the material flow direction and fitted and fixed to the male die body are formed separately by one each. It is characterized by. In the present invention, the core is constituted by a plurality of projecting rods which are separately formed one by one, and each projecting rod has a much simpler structure than a conventional core. Therefore, normal electric discharge machining and wire electric discharge machining can be eliminated as much as possible, and other electric discharge machining such as grinding and cutting can be performed. In the case of mere mechanical processing such as grinding, etc., phenomena such as the formation of an abnormal melting layer (uneven layer) as in the case of using electric discharge machining, chipping and minute falling off are also observed. Will not occur. For this reason, the durability of the core can be significantly improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the projection bar is formed by extruding the material into a predetermined shape by contacting a projection provided at one end with the material. The projection base on the other end side is provided with a locked part which is locked to the male die body and regulates movement of the projection bar in the axial direction. In the present invention, in fixing the projection bar to the male die body, the locked portion provided on the projection base is locked to the male die body, thereby restricting the movement of the projection bar in the axial direction. ing. When extruding the material, the projection bar is subjected to an excessive force such that it moves in the axial direction due to friction between the material and the material. , So that the protrusion bar does not move in the axial direction.

The invention according to claim 3 is the invention according to claim 1 or 2
In the invention according to the first aspect, at least a portion of the projection bar which comes into contact with the material is processed by grinding. In the present invention, the portion where the core is subjected to the most load and wear is advanced, and the portion that comes in contact with the material is processed by grinding, and the grinding is finished to a flat shape with less unevenness by suppressing the surface roughness. Therefore, when a coating film is formed on a portion that comes into contact with the same material, the bonding strength between the core base material and the coating film can be increased, and also in this respect, the durability of the core can be improved.

The invention according to claim 4 is the invention according to claim 1 or 2.
In the invention according to the first aspect, the projection bar-shaped body is processed by polishing at least a portion in contact with the material. In the present invention, the portion where the core is subjected to the most load and wear is advanced, and the portion in contact with the material is processed by polishing, and the polishing is finished to a precise flat shape by further suppressing the surface roughness. Therefore, when a coating film is formed on a portion in contact with the material, the bonding strength between the core base material and the coating film can be further increased, and in this regard, the durability of the core can be further improved.

The invention according to claim 5 is the invention according to claim 1 or 2
In the invention according to the above, the projection bar is preferably finished by polishing after at least a portion in contact with the material is processed by grinding. In the present invention, the portion where the core is subjected to the most load and wear is advanced, the portion that comes into contact with the material is processed by grinding and then finished by polishing. The processing accuracy is improved, and both processing speed and processing accuracy can be satisfied.

The invention according to claim 6 is the invention according to claim 1 or 2
In the invention according to the above aspect, the protrusion bar-shaped body is finished by polishing after at least a portion in contact with the material is processed by electric discharge machining. In the present invention, the portion where the core is subjected to the most load and wear is advanced, the portion in contact with the material is processed by electric discharge machining and then finished by polishing, and the machining speed is increased by electric discharge machining and the surface of the core is polished by polishing. The processing accuracy is improved, and both processing speed and processing accuracy can be satisfied.

The invention according to claim 7 is characterized in that, in the invention according to any one of claims 1 to 6, an uneven portion is formed along at least an outer periphery of a tip end of the projection along an axial direction. . In the present invention, since the uneven portion is formed at least on the outer periphery of the distal end of the projecting portion, an uneven portion along the axial direction is formed on the inner surface of the flat multi-hole tube formed by the die. The heat transfer coefficient of the tube is significantly improved because the heat transfer area increases and the turbulence occurs in the refrigerant flowing through the tube.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIGS. 1 to 6 show a first embodiment of the present invention. FIGS. 1 and 2 show a male die 1 among extrusion dies including a male die and a female die according to the present invention.
Since the structure of the female die 41 is the same as that described in the above-described conventional example, the description thereof is omitted here. Also, regarding the male die 1, the same components as those of the male die 31 shown in the aforementioned conventional example are used. Are denoted by the same reference numerals, and a part of the description is omitted.

The male die 1 is also used by being mounted on an extruder (not shown) in a state where the fitting portions are fitted and connected to the female die 41 shown in FIGS.
That is, the protrusion 3a of the male die 1 is connected to the female die 41.
And the fitting portion 37 of the male die 1 is fitted into the concave groove portion 51 of the female die 41, and the step portion 33 of the male die 1 is further fitted into the groove portion 4 of the female die 41.
5 and are integrated with each other. In this state, it is used by being mounted on an extruder.

The male die 1 is composed of a male die body 2
And a core 4 fitted and fixed substantially at the center of the male die body 2 and having the projection 3a. Core 4
Are formed by the protrusion 3a and the protrusion base 3b extending upstream from the protrusion 3a with respect to the material flow direction and fitted and fixed to the male die body 2.
Are formed one by one. The projection bar 5 is formed on a mating surface S of a male die main body base 2A and a male die main body lid 2B, which will be described later, at least in the center of which is divided in the thickness direction.
A plurality of grooves 12 provided on the male die body base 2A side.
And are fitted and fixed in parallel with each other.

As shown in FIG. 3, there are provided two types of protrusion rods 5 at the right and left ends: a protrusion rod 5a at the end and a protrusion rod 5b at the center. The protruding rod 5a at the end is formed, for example, in a semicircular cross section, and a concave portion 6 is formed at a position corresponding to the chord and slightly toward the center from the front end, and is extruded. A good flow of the material in the direction of the tip during molding can be ensured. On the other hand, the projection bar 5b at the center has, for example, a rectangular cross section, and a recess 6 for ensuring a good flow of the material is also formed on each of the left and right sides. . In addition, the projection bar 5a at the end is provided.
On both upper and lower surfaces of the projection bar 5b at a position slightly closer to the center from the base end of the projection base 3b, a groove 7... In a direction perpendicular to the length direction of the projection bar 5 Are formed along. A common stopper 8 described later is engaged with the groove 7. The concave portion 6 is not always required, and may not be necessary if the flow of the material itself is good. The protruding portion bar 5 is a molding portion in which the protruding portion 3a provided at one end contacts a material and extrudes the material into a predetermined shape. Further, the protrusion base 3b on the other end side of the protrusion bar is locked to the male die body 2 via a common stopper 8 to be described later to restrict the movement of the protrusion bar 5 in the axial direction. A groove 7, which is a locked portion, is provided.

The projecting rod 5 is not limited to the one shown in FIG. For example, as shown in a plan view in FIG.
Even if the protrusion bar 5c has the same shape from one end to the other end, or as shown in FIG. 4 (b), only the tip portion that comes into contact with the material is a narrow portion 5da.
The central portion and the base end may be a projecting rod 5d having an enlarged diameter portion 5db. Further, as shown in FIG. 5ea, and a protruding rod 5e having a narrow portion 5eb at the center and the base end may be used. Further, the cross section may have a square shape or a rhombic cross section.

As shown in FIG. 6, the entirety of the outer periphery of the distal end of the projection 3a of the projection bar 5 is provided with the irregularities 3aa.
May be formed along the axial direction of the projection 3a. Examples of the specific shape of the uneven portion include those shown in FIGS. 6A to 6E in addition to the zigzag uneven portion in which triangles are continuous. In FIG. 6A, each peak and valley is formed not in a triangle but in a square shape. FIG.
The one shown in (b) is the same square shaped mountain valley,
The width of the projection is set to be larger than the width of the depression.
Conversely, the one shown in FIG. 5C is one in which the width of the convex portion is set smaller than the width of the concave portion. In FIG. 6D, the cross-sectional shape of the protrusion 3a is formed in a substantially square shape. In FIG. 6E, the cross-sectional shape of the protrusion 3a is formed in a substantially rhombic shape.

The protrusion bar 5 (5a, 5b, 5c, 5
d and 5e) are made by grinding a cemented carbide or high-speed steel. The male die body 2 shown in FIGS. 1 and 2 is a material softer than the core 4, for example, high-speed steel or hot steel. Made of die steel. In the case where the protruding rods 5 are processed,
It is not always necessary to perform all the processing by mechanical processing such as grinding, and the part that comes into contact with the material, which is the part where the most load is applied and the wear proceeds, is processed by mechanical processing, preferably grinding or polishing. Is enough. In the case where the rod 5a having a semicircular cross section shown in FIG. 3 is formed by grinding or the like, first, a rod having a circular cross section is extruded and then formed by grinding or the like. It is obtained by halving in the vertical direction by means. If necessary, at least a portion of the projecting rod 5 which contacts the material may be processed by grinding and then precision finished by polishing, or at least a material of the projecting rod 5 may be used. May be finished only by polishing. In the case where wire electric discharge machining is used to halve the rod-shaped body, additional processing such as grinding or polishing is performed at least on a portion required to be in contact with the material, and the abnormal melting layer on the surface is scraped off.

As shown in FIGS. 1 and 2, the male die body 2 has at least a central portion divided in a thickness direction.
It has a two-part structure consisting of a male die main body base 2A and a male die main body lid 2B. Male die body base 2
A is a basic configuration having a flat plate portion 10 set to a thickness slightly larger than half the thickness of the male die main body 2 and thick portions 11 provided on both left and right sides of the flat plate portion 10, respectively. It is. At the center of the flat plate portion 10, grooves 12 for fitting the protrusion bar members 5 are formed in parallel with each other at equal intervals. A lower portion 3 of the flat portion 10, which constitutes the step portion 33, is located at a downstream end of the flat portion 10 with respect to the material flow direction so as to be located outside the groove 12.
3a are formed, and at the center thereof, the protruding rods 5 are formed.
A triangular portion 13 having substantially the same height as that of is formed to protrude outward. The triangular portion 13 is for ensuring a smooth flow of the material.

Note that the groove for fitting the projecting rod in the center of the flat plate portion 10 of the male die body 2 is shown in FIGS.
As shown in FIG. 5A, a plurality of projecting rods 5 are in close contact with each other, as shown in FIG. 5B, without being limited to a large number of grooves 12 arranged in parallel at intervals as shown in FIG. May be wide grooves 12a to be fitted together. In this case, as the protruding portion rod-like body fitted into the wide groove 12a, a 5d having a narrow portion 5da at the tip end portion as shown in FIG. 4B is used.

As shown in FIG. 2, the left and right thick portions 1
Tapered surfaces 11a, 11a gradually narrowing upward are formed on the side surfaces on the center side of 1, 11 and the tapered surfaces 16a, 16a formed on the male die body lid 2B are engaged with the tapered surfaces 11a, 11a. By joining, the male die main body lid 2B is connected to the male die main body base 2.
The distance from A in the thickness direction is regulated. Further, through holes 14 are formed on the left and right sides of the male die body base 2A for engaging with a cap 20 described later. The cap 20 side of the through hole 14 of the male die body base 2A is formed in a half-shape.

In FIG. 2, the male die body cover 2B is formed in a substantially T-shape in plan view, and has a rectangular portion 16 which covers above the grooves 12 of the male die body base 2A, and one end of the rectangular portion 16. Branches 17 extending left and right,
17 The right and left sides of the rectangular portion 16 are formed with the tapered surfaces 16a that engage with the tapered surfaces 11a of the male die body base 2A. In addition, the square part 16
An upper portion 33b constituting the step portion 33 is formed at a downstream end portion with respect to the material flow direction. In addition, on the upper surface of the square 16, the inflow portion whose thickness is gradually reduced toward the downstream side with respect to the material flow direction is formed, and the outer surface of the flat portion of the male die body base (corresponding to this) is formed. (Invisible in FIG. 2), a flow-in portion where the plate thickness gradually decreases is formed. The left and right branches 17,
On the lower surface of FIG. 2 in FIG. 2, a half portion for forming the through hole 14 is formed.

As shown in FIG. 2, the common stopper 8 is formed in a U-shape in plan view, and convex portions 15 are formed at both left and right end portions. The end of the common stopper 8 is reinforced. A slit 18 is formed in the center of the common stopper 8 in the thickness direction, and the groove 7 formed on the upper and lower surfaces of the projection bar 5 is engaged with the slit 18.
The tip of the pin 19 engaged with the hole 8a formed in the common stopper 8 is connected to the engaging hole 1 of the male die body base 2A.
By being locked to Oa, the common stopper 8 and the projecting rod 5 locked to the common stopper 8 are fixed to the male die body 2.

As shown in FIGS. 1 and 2, at the upstream end of the male die 1 with respect to the flow direction of the raw material, the pressing force of the raw material directly acts on the upstream end of the male die 1 during the extrusion of the raw material. A cap 20 is attached to prevent this. The thickness of the cap 20 is set to be substantially the same as the thickness of the male die 1. A hole 21 is formed at the downstream end of the cap 20. The base 21 of the protrusion bases 3b of the protrusion rods 5 and the common stopper 8 are housed in the hole 21. A gap is formed between the center of the upstream end of the male die 1 and the center of the cap 20. The hole 21 has an area approximately equal to or slightly larger than the upstream end of the core 2 and is set so as to cover the upstream end of the core 2.

As shown in FIGS. 1 and 2, a positioning pin (not shown) is inserted into the through hole 14 of the male die body 2, and the tip of the pin is inserted into a hole 22 formed in the cap 20. As a result, the cap 20 is positioned and fixed to the male die 1.

Next, the operation of the extrusion die having the above configuration will be described. The male die 1 shown in FIG.
Are fitted to an extruder (not shown) in a state where the fitting portions are fitted to each other with the female die 41 shown in FIG. . That is, a material (a billet) such as aluminum inserted into a hole of a container connected to a through hole serving as a material inflow path of the extrusion device is pressed toward a die by a pressing plate (stem), and the billet to be extruded is formed by a male die 31 Flows into the gap between the projection 3a and the die hole 49 of the female die 41, and the billet is moved from the die hole 49 to the projection 3a.
The point that the flat multi-hole tube Ca as shown in FIG. 13 is extruded when passing through the gap between the conventional example and FIG.

Here, since the core 4 including the protruding portion 3a, which is the most worn portion of the male die 1 shown in FIG. 1, is made of cemented carbide or high-speed steel having excellent wear resistance, the male die 1 Of course, the core 4 shown in FIG. 1 and FIG. 2 can be further reduced by a plurality of projection bar-like bodies 5 (5a, 5b) formed one by one. , 5c, 5d, 5e), each of which has a rod 5 (5a, 5b, 5c, 5c).
5d and 5e) have a much simpler structure than the conventional core 31a as shown in FIG. 21, so that they can be processed by grinding instead of electric discharge machining. In the case of mere mechanical processing such as grinding, an abnormal melting layer (irregular layer) may be formed on the surface as in the case of using electric discharge machining, and phenomena such as chipping and minute falling off may also occur. Because of this, the durability of the projection bar-shaped members 5, that is, the core 4 can be dramatically improved.

In addition, since the projections 3a of the projection bar 5 are formed at least on the outer periphery of the distal end with the irregularities 3aa (FIG. 6), the inner surface of the flat multi-hole tube formed by this die is placed in the axial direction. The heat transfer area of the tube is dramatically improved because the heat transfer area increases and the turbulent flow occurs in the refrigerant flowing through the tube.

The male die body 2 shown in FIG. 2 has a male die body base 2A having a central portion divided in the thickness direction.
And a male die cover 2B, and a projection bar 5 (5a, 5a, 5a, 5b) is provided on the mating surface S of the male die base 2A and the male die cover 2B.
b, 5c, 5d, 5e), the plurality of projecting rods 5 (5a, 5b, 5c, 5d, 5e) are
It can be easily set at the center of the male die main body 2 and, furthermore, by simply removing the male die main body lid 2B from the male die main body base 2A, the protrusion bar 5 (5a,
5b, 5c, 5d, and 5e) can be easily taken out, and the workability during core maintenance is excellent.

In FIGS. 2 and 3, the projection base 3 of each of the projection rods 5 (5a, 5b, 5c, 5d, 5e) is shown.
b, a groove 7 orthogonal to the longitudinal direction is formed, and a common stopper 8 for restricting the longitudinal movement of the projection bar 5 (5a, 5b, 5c, 5d) is engaged with the groove 7. Because
When the material is extruded, it is possible to restrict the movement of each projection bar 5 together with the material, and it is also excellent in terms of assemblability of the projection bar 5.

<Second Embodiment> FIGS. 7 to 12 show a second embodiment of the present invention. The first embodiment described above uses a flat multi-hole tube C having a rectangular cross section as shown in FIG.
This is an example in which a is extruded. However, in the second embodiment shown here, a flat multi-section having a shape in which a part such as a circular section, an elliptical section, or a circular section is deleted as shown in FIG. This is an example in the case of extruding the hole tube Cb. In order to extrude a flat multi-hole tube Cb having a circular or elliptical cross section, it is necessary to use a projection having a circular or elliptical cross section for the extrusion core. When the flat multi-hole tube Cb having a circular or elliptical cross section is used as described above, it can withstand a case where the pressure of the refrigerant flowing in the tube is relatively high, so that the flow rate of the refrigerant can be further increased, and as a result, In addition, the heat exchange rate can be further improved.

It should be noted that most of the structure of the second embodiment is the same as that of the above-described first embodiment, and the description thereof is given the same reference numerals as those of the first embodiment. And the description thereof will be omitted. In the second embodiment, as described above, the protrusion bar 25 is provided in the form shown in FIG.
As shown in (a), the whole is formed in a circular cross section, and grooves 7... Are respectively formed on upper and lower surfaces at positions slightly closer to the center side from the base end of the protrusion base, and the protrusion bar 5 is formed. Are formed along a direction orthogonal to the length direction. The common stopper 8 described above is engaged with the groove 7. Projection rod 2
As shown in FIG. 9 (b), the left and right sides of the circular cross section may be omitted from the plane, as shown in FIG. 9 (b). Alternatively, as shown in FIG. Only the left and right sides of the circular cross section have a shape in which each of the left and right sides is deleted in a planar shape, and the protrusion base 52b may have a circular cross section having a larger diameter than the protrusion 25a at the tip. Note that the cross-sectional shape of the projection bar 25 is not limited to a circle, but may be an ellipse, or a part of the ellipse, for example, the left and right sides may be deleted.

As shown in FIG. 10, the protrusion 25a of the protrusion bar 25 has an uneven portion 25a over the entire outer periphery of the tip.
a may be formed along the axial direction of the projection 25a. As the specific shape of the uneven portion 25a, in addition to the zigzag uneven portion in which triangles are continuous, FIGS.
There are the following. In FIG. 11A, each peak and valley is formed not in a triangle but in a square shape. In FIG. 11B, the width of the convex portion is set to be larger than the width of the concave portion, although the peaks and valleys have the same square shape. Conversely, the one shown in FIG. 11C is one in which the width of the projection is set smaller than the width of the depression. FIG.
As shown in (d), the cross-sectional shape of the projection bar is substantially elliptical. In FIG. 11E, the tip corner of the projection is rounded.

As shown in FIG. 8, the male die body base 2
A large number of grooves 26 are formed in the center of the flat plate portion 10 of A in a semicircular shape so as to be parallel to each other and to match the outer shape of the projection bar 25. On the other hand, a large number of grooves 27 are formed in a semicircular shape on the lower surface in FIG. 8 of the male die body cover 2B so as to be parallel to each other. That is, as shown in FIG. 12 (a), the projection bar 25 is formed by the male die body base 2A and the male die body cover 2B.
Are fitted and fixed to semi-circular grooves 26, 27,... Formed at an interval from each other.

The method of fixing the projecting rod 25 is not limited to the above-described fixing method. As shown in FIG. 12B, the male die main body base 2A and the male die main body lid 2B are used.
May be fitted into and fixed to semicircular grooves 26... 27 formed continuously without leaving a gap between each other. In this case, the projection bar 25 has a shape shown in FIG. 9C. Further, as shown in FIG. 12C, a large number of parallel grooves 26a having a triangular cross section are formed on one of the opposing surfaces of the male die body base 2A and the male die body cover 2B, for example, on the male die body base 2A side. Then, a flat plate portion 27a is formed on the other side of the male die main body lid portion 2B side, and the projection bar-like bodies 25 are sandwiched and fixed between the many parallel grooves 26a and the flat plate portion 27a. You may.

Also in this embodiment, the core 4 shown in FIG.
5, each of the projection bar-shaped members 25 has a much simpler structure than the conventional core 31a as shown by a two-dot chain line in FIG. Can be processed. When the projection bar 25 is formed by simple mechanical processing such as grinding, an abnormal melting layer (irregular layer) as in the case of using electric discharge machining is formed or chipped. Since there is no occurrence of a phenomenon such as a small dropout and a small drop-out, the same effect as that of the first embodiment described above, that is, the durability that the durability of the protruding rods 25... Can be played.

<Third Embodiment> FIGS. 13 to 16 show a third embodiment of the present invention. In the first and second embodiments described above, an example is shown in which the male die body 2 having a two-part structure in which the central part is divided in the thickness direction is used.
In the embodiment, an example in which the male die body 28 having an integral structure is used will be described. The basic configuration of the male die body 28 is as follows.
The structure is the same as the structure in which the male die main body base 2A and the male die main body lid 2B of the male die main body 2 having the two-part structure described above are engaged with each other.

That is, at the center of the male die body 28 in the thickness direction where the inflow portion 36 is formed, a large number of circular holes 28a are formed from one end of the male die main body along the flow direction of the material. It is formed at predetermined intervals in the width direction of the male die body 28 so as to extend to the other end. An opening 28b is formed in the end surface of the male die body 28 on the upstream side with respect to the material flow direction, and the opening 28b is connected to the circular holes 28a,. Then, these circular holes 28a,.
The projecting rods 29,...
b, the distal end is projected from one end of the male die main body 28, and the base large-diameter portion 29a formed in a substantially square shape of the projection rod 29 is engaged with the opening and set.

A cap 20 is attached to the upstream end of the male die body 28 with reference to the material flow direction.
It is not always necessary to provide the cap 20, but when the cap 20 is omitted, the base ends of the projecting rods 29,... So that the projecting rods 29,. It is preferable that the large diameter portion 29a be firmly fixed to the opening 28b by a fixing means such as shrink fitting. A large number of circular holes 28a,.
In order to form a hole, there is a method in which a prepared hole is first made by a small-hole electric discharge machine, and then a wire is passed through the prepared hole to finish-work the prepared hole so as to be as close to a perfect circle as possible. According to such a method, the small-diameter circular hole 28 into which the projecting rods 29 can be inserted and set.
can be formed in a shape close to a perfect circle at a predetermined angle via an extremely thin partition wall.

Also in this embodiment, the core 4 is
It is composed of a plurality of projecting rods 29 which are separately formed one by one. Since each projecting rod 29 has a simple structure, it can be processed by grinding instead of electric discharge machining. The effect is that the durability of the projection bar-shaped body 29, that is, the core 4, can be remarkably improved.

The above embodiments are merely examples, and the design can be changed as needed unless the gist of the invention is changed. For example, in the first and second embodiments, the common stopper 8 for restricting the axial movement of the projection rods 5 and 25 is engaged with the groove 7 of the projection base 3b. The protrusions 5 and 25 are provided with protrusions perpendicular to the axial direction at the ends thereof so that the entire protrusions 5 and 25 have an L-shape. The portion may be engaged with the end face of the male die body 2 to restrict the axial movement of the projection bar-shaped bodies 5 and 25.

In the above embodiment, the present invention will be described with reference to an example of an extrusion die composed of a male die having a substantially rectangular plate shape and a female die having a substantially cylindrical shape. However, the present invention is not limited to this, and it goes without saying that the present invention is also applicable to a general extrusion die in which both the male die and the female die have a substantially columnar appearance.

[0056]

As described above, according to the present invention, the core is constituted by a plurality of projecting bars each formed separately, and each of the projecting bars is different from the core. Since it has a much simpler structure, it can be processed not only by electric discharge machining but also by other processes such as grinding and / or grinding. In the case of mere mechanical processing such as grinding, the surface shape can be finished to a flat shape with less unevenness as compared with the case where electric discharge machining is used, and in this case, the surface of the protrusion bar For example, when a titanium-based coating film having excellent wear resistance is formed, a strong bonding strength between the base material and the coating film can be obtained, and a core having excellent durability can be obtained. In the case of simple mechanical processing such as grinding, an abnormal melting layer (irregular layer) is formed as in the case of using electric discharge machining, and phenomena such as chipping and minute falling off may also occur. However, also in this respect, the durability of the core can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a male die of an extrusion die according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the male dice according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view of the projection bar according to the first embodiment of the present invention.

FIGS. 4A to 4C are diagrams showing other examples of the projection bar according to the first embodiment of the present invention.

FIGS. 5 (a) and 5 (b) are cross-sectional views each showing an assembled state of a projection bar according to the first embodiment of the present invention.

FIGS. 6 (a) to 6 (e) are diagrams showing examples of uneven portions provided on the outer periphery of the distal end of the projection of the projection bar according to the first embodiment of the present invention.

FIG. 7 is a perspective view of a flat multi-hole tube showing an example formed by an extrusion die according to a second embodiment of the present invention.

FIG. 8 is an exploded perspective view of a male die according to the second embodiment of the present invention.

FIG. 9 is a perspective view of a projection bar according to the second embodiment of the present invention.

FIG. 10 is a perspective view showing another example of the projection bar according to the second embodiment of the present invention.

FIGS. 11 (a) to 11 (e) are second views of the present invention, respectively.
It is a figure which shows the example of the uneven | corrugated part provided in the outer periphery of the front-end | tip of the protrusion part of the protrusion part rod-shaped body of 1st Embodiment.

FIGS. 12 (a) to 12 (c) are cross-sectional views showing another method of fixing the projection bar according to the second embodiment of the present invention.

FIG. 13 is a perspective view showing a male die of an extrusion die according to a third embodiment of the present invention.

FIG. 14 is an exploded perspective view of a male die according to the third embodiment of the present invention.

FIG. 15 is a cross-sectional view of the male dice according to the third embodiment of the present invention.

FIG. 16 is a perspective view of a projection bar according to the third embodiment of the present invention.

FIG. 17 is a perspective view showing an example of a male die among conventional extrusion dies.

FIG. 18 is a sectional view of the die.

FIG. 19 is a cross-sectional view of another side of the die.

FIG. 20 is a perspective view of a flat multi-hole tube showing an example formed by an extrusion die.

FIG. 21 is a perspective view of a tip end of a core showing a problem of the conventional extrusion die.

[Explanation of symbols]

Reference Signs List 1 male die 2 male die body 2A male die body base 2B male die body lid 3a projection 3b projection base 4 core 5 projection bar 7 groove 8 common stopper 12 groove 20 cap 25 projection bar 28 protrusion male rod 29 male die body 29 The mating surface of the male die body base and the male die body lid

Claims (7)

[Claims] 1. A male die having a plurality of projections arranged at a predetermined interval from each other, and a female die having a mold hole into which the projections are inserted. Extrusion processing in which a flat multi-hole tube is extruded by being fitted to an extruder in a state of being fitted and connected, and extruding a material from a gap formed between the mold hole and the protrusion. In the die, the male die includes a male die main body, and a core fitted and fixed to substantially the center of the male dice main body and having the plurality of protrusions, and the core is configured such that the material flow direction from the protrusions and the protrusions And a protrusion base portion extending to the upstream side with respect to the base and fitted and fixed to the male die body, and each of the protrusion rods is formed separately by one. Extrusion die. 2. The projection bar-shaped body has a projection provided at one end serving as a molding portion for extruding the material into a predetermined shape by contacting the material, and the male die is provided at the other end of the projection base. The extrusion die according to claim 1, further comprising a locked portion that is locked to the main body and restricts movement of the projection bar in the axial direction. 3. The extrusion die according to claim 1, wherein at least a portion of the protruding portion bar that comes into contact with the material is processed by grinding. 4. The extrusion die according to claim 1, wherein at least a portion of the projection bar-shaped body that comes into contact with the material is processed by polishing. 5. The extrusion rod according to claim 1, wherein at least a portion of the projection bar which comes into contact with the material is finished by grinding and then polishing. dice. 6. The extrusion die according to claim 1, wherein the projection bar-shaped body is finished by polishing after at least a portion in contact with the material is processed by electric discharge machining. 7. The extrusion die according to claim 1, wherein a projection and a depression are formed on at least the outer periphery of the tip of the projection along the axial direction.