JP2573141B2 - Extrusion molding method and apparatus - 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 molding method and an apparatus therefor, and more particularly, to an extrusion molding method for a workpiece made of metal without damaging the inner surface of a cylindrical container. It relates to a possible extrusion method and its device.

[0002]

2. Description of the Related Art When manufacturing a cylindrical container made of metal, for example, as shown in FIG. 8A, a supporting punch 6 is inserted into a through hole 4 in a cylindrical die 2, and
Extrusion molding is generally used in which the workpiece 8 supported by the support punch 6 is pressed by a pressing punch 10 so that the workpiece 8 is extruded from the die 2 and processed.
This extrusion has the advantages of saving material, shortening one processing time, and repeatedly and continuously processing a product with uniform accuracy.

[0003]

However, in the extrusion molding according to the above-mentioned prior art, after the extrusion, FIG.
As shown in the figure, when extracting the pressing punch 10 surrounded by the extruded workpiece 8a, the inner wall surface 12 of the extruded workpiece 8a and the outer peripheral surface 14 of the pressing punch 10 come into contact with each other, There is a disadvantage that scratches (hereinafter referred to as galling) are generated on the inner wall surface 12 of the workpiece 8a, that is, the inner surface of the cylindrical container. In this case, in a container requiring hermeticity, for example, an air cylinder, the galling may cause air leakage and impair hermeticity.

[0004] The present invention has been made to overcome the above-mentioned disadvantages, and it is possible to prevent the occurrence of galling on the inner surface of a cylindrical container made of metal when the container is manufactured. It is an object of the present invention to provide a simple extrusion molding method and an apparatus therefor.

[0005]

In order to achieve the above object, the present invention provides a front extrusion method for extruding a workpiece in the same direction as a pressing direction, the method comprising the steps of inserting the workpiece into a die. Pressing the workpiece toward the support punch side that supports the workpiece via the pressing punch, the workpiece expands in diameter from the inner diameter side of the die to the outer side, and the extruded workpiece is pressed. Extruding the workpiece along the axial direction of the support punch while maintaining a state in which a gap is defined between the inner wall surface and the outer peripheral surface of the support punch that supports the workpiece; and Displacing toward the pressing punch side, reducing the diameter of the extruded workpiece from the inner diameter of the die to the outer side toward the inner peripheral surface side of the support punch, and separating the workpiece from the support punch And a step of causing

The present invention also provides a backward extrusion method for extruding a workpiece in a direction opposite to a pressing direction, wherein the workpiece is inserted into the die with the upper surface of the workpiece protruding from the upper surface of the die, and the workpiece is inserted into the die. A step in which the workpiece is supported by the support punch inserted into the hole in the die, and in a state in which the workpiece is supported by the support punch, the workpiece is moved toward the support punch by displacing the pressing punch. Pressing, and displacing the die in the same direction as the pressing direction of the pressing punch while the pressing surface of the pressing punch and the upper surface of the die are held at a predetermined separation distance. I do.

Further, according to the present invention, there is provided an extrusion molding apparatus for extruding a workpiece in the same direction as the direction in which the workpiece is pressed, wherein a through hole is defined, and an inner wall surface of the hole has a substantially same diameter as an inlet. A first inner wall surface extending downward from the first
A tapered surface that is reduced in diameter from the end of the inner wall surface to the lower side, an annular convex portion that continues downward from the end of the tapered surface with substantially the same diameter, and a reverse that expands downward from the end of the annular convex portion. A die having a tapered surface, a second inner wall surface having substantially the same diameter and continuing from an end of the reverse taper surface to a lower side, and a workpiece inserted into the first inner wall surface of the die being moved downward; And a supporting punch for supporting the workpiece pressed by the pressing punch.

[0008]

In the extrusion molding apparatus according to the present invention, the workpiece is inserted into the first inner wall surface in the die, and presses the workpiece toward the support punch via the pressing punch. The pressed workpiece is squeezed and reduced in diameter by the tapered surface and the annular convex portion in the die, and is further extruded radially outward by the reverse tapered surface. The pushed-out angle of the pushed-out portion is regulated by the second inner wall surface. As a result, the workpiece is extruded along the axial direction of the support punch while having a gap between the inner wall surface of the workpiece that has been extruded with an increased diameter and the outer peripheral surface of the support punch.

On the other hand, by displacing the supporting punch toward the pressing punch, the expanded and extruded portion is narrowed and reduced in diameter by the reverse tapered surface and the annular convex portion of the die. In this case, since the inner wall surface of the extruded portion and the outer peripheral surface of the support punch are reduced in a non-contact state, the inner wall surface of the extruded portion and the outer peripheral surface of the support punch rub against each other and the inner wall surface of the workpiece is rubbed. The workpiece can be taken out of the support punch without flaws.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing an extrusion molding method according to the present invention.

FIGS. 1 to 3 show an extrusion molding apparatus for carrying out an extrusion molding method according to claim 1 of the present invention. FIG. 1 shows a workpiece inserted into a die with a punch. FIG. 2 is a cross-sectional view showing an initial state of pressing and extruding.
Is a cross-sectional view showing a state where the extrusion is completed, and FIG. 3 is a cross-sectional view showing a state at the time of knockout. In addition, the said molding apparatus employ | adopts front extrusion pushed out in the same direction as a pressurization direction through a punch.

The extrusion molding apparatus 20 is provided with a support base 22 having a through hole substantially at the center thereof. Four cylinders 26 having cylinder rods 24 displaced in directions of arrows X and Y are provided on the outer end side of the support base 22 (however,
The two cylinders are omitted in the figure) are fixed to the support base 22. A plate 28 that is displaced in the direction of arrow Y under the driving action of the cylinder 26 during knockout is fixed to the tip of the cylinder rod 24. In a substantially central portion of the plate 28, a substantially circular hole 3 having a diameter slightly larger than a diameter of a support punch 30 described later.
2 are defined.

The plate 28 is for preventing the influence of the vibration of the support punch 30 during extrusion molding by inserting the support punch 30 through the hole 32. Four guide rods 34 (however, two guide rods are omitted in the drawing) are fixed upright on the support base 22 substantially at the center of the support base 22. A through hole is defined at a substantially central portion of the support base 22, and a knockout pin 36 that is inserted through the through hole and displaced in the directions of arrows X and Y under the driving action of a cylinder (not shown) is provided. A support plate 38 is fixed to the tip of the knockout pin 36. A support punch 30 for supporting a workpiece 39 during extrusion molding is fixed to the support plate 38 via a locking member 40. First and second support members 44 and 46 for holding a cylindrical die 42 are fixed to an upper portion of the guide rod 34.

The die 42 has a through hole 48 defined therein. As shown in FIG. 4, the inner wall surface of the hole portion 48 has an annular first inner wall surface 50 which is continuously formed with substantially the same diameter near the upper entrance of the die 42 and the first inner wall surface 50.
It has a tapered surface 52 that is inclined from the end of the inner wall surface 50 toward the axial center of the hole 48 to reduce its diameter, and an annular convex portion 54 that is continuous from the end of the tapered surface 52 with substantially the same diameter. further,
The inner wall surface of the hole 48 has a reverse tapered surface 56 which is formed so as to be radially outwardly enlarged from the end of the annular convex portion 54 so as to be inclined.
And an annular second inner wall surface 58 that continues from the end of the reverse tapered surface 56 with substantially the same diameter. In this case, the first inner wall surface 50 is for holding the workpiece 39, and the tapered surface 52 and the annular convex portion 54 are for compressing and reducing the diameter of the workpiece 39. The tapered surface 56 is for expanding the workpiece 39 in a radially outward direction of the support punch 30 and extruding the same.
Numeral 8 is for restricting the angle of the extruded portion whose diameter has been expanded by the tapered surface 52.

A holder plate 60 connected to displacement means (not shown) is provided above the die 42, and a substantially cylindrical pressing punch 64 is fixed to the holder plate 60 via a punch holder 62. A tapered surface 6 that comes into contact with the tapered surface 52 of the die 42 at the end of the pressing punch 64 when the pushing of the workpiece 39 is completed.
6, the pressing punch 6 excluding the tapered surface 66.
4 has a diameter substantially equal to the diameter of the first inner wall surface 50 of the die 42.

The extrusion molding apparatus 20 according to this embodiment is basically configured as described above, and the operation thereof will be described next.

First, the workpiece 39 is placed in the first die 42 in the die 42.
It is inserted into the inner wall surface 50 (see the broken line shown in FIG. 1). Therefore, the pressing punch 64 is driven under the driving action of a displacement means (not shown).
Is displaced in the direction of the arrow X to bring the tip of the pressing punch 64 into contact with the workpiece 39. The workpiece 39 is pressed in the arrow X direction by the pressing punch 64,
The outer peripheral surface on the lower side of the workpiece 39 is reduced along the tapered surface 52 of the die 42 and the annular convex portion 54 to reduce the diameter (see FIG. 4A).

In this case, it is preferable that the workpiece 39 has a substantially columnar shape and has a diameter substantially equal to the diameter of the first inner wall surface 50. The outer diameter accuracy may not be so high as compared with the extrusion molding method in the prior art. In the extrusion molding method according to the prior art, the distance between the inner wall surface of the die 42 and the outer peripheral surface of the workpiece 39 affects the wall thickness accuracy of the processed cylindrical container. It is necessary to match the outer diameter dimension of 39 with high precision. On the other hand, in the present embodiment, the accuracy of the outer diameter of the workpiece 39 does not matter so much. When the workpiece 39 is pressed by the pressing punch 64, the outer diameter of the workpiece 39 is reduced by the tapered surface 52 and the annular convex portion 54, and the workpiece 39 is reduced in diameter.
As a result, there is no room for forming a gap between the outer peripheral surface of the workpiece 39 and the inner wall surface of the die 42.

Next, the tapered surface 52 and the annular projection 5
The bottom end surface of the workpiece 39 reduced in diameter in FIG. 4 is further pressed in the direction of the arrow X via the pressing punch 64 to be displaced downward from the end of the annular convex portion 54, and FIG.
As shown in the figure, the bottom end face of the workpiece 39 is
0 abuts on the tip. In this case, as shown in FIG.
The plate 28 supporting the support punch 30 is a support base 2
Since the support punch 30 is located on the upper side and the displacement of the support punch 30 with respect to the lower side is prevented, the support punch 30 acts to press the workpiece 39 relatively upward. Therefore,
When the workpiece 39 is further pressed, the end of the bottom surface of the workpiece 39 excluding the portion that comes into contact with the support punch 30 is curved toward the outer peripheral surface side of the support punch 30 as shown in FIG. 4B. And deform.

At this time, the extruded portion 39a of the workpiece 39 is constrained by the second inner wall surface 58 extending below the reverse tapered surface 56 and is extruded from the axis of the support punch 30. The extrusion direction with respect to the radial outside direction is regulated. As a result, as shown in FIG. 4C, the extrusion angle of the extruded portion 39b of the workpiece 39 is restricted by the second inner wall surface 58, and is separated from the outer peripheral surface of the support punch 30 so that the axial center of the support punch 30 Deformation with a gap substantially parallel to (see FIG. 2). The hole 48 in the die 42
The thickness of the extruded portion 39b can be adjusted by adjusting the position of the distal end surface of the support punch 30 in the above.

In this manner, as shown in FIG. 1, when the tapered surface 66 at the tip of the pressing punch 64 comes into contact with the tapered surface 52 of the die 42, the extrusion is completed. Subsequently, the support table 2 is driven under the action of driving the respective cylinders (not shown).
The knockout pin 36 inserted through the through-hole 2 and the cylinder rod 24 having the plate 28 connected to the distal end are displaced in the direction of arrow Y. The outer diameter of the portion extruded away from the outer peripheral surface of the support punch 30 is formed slightly larger than the inner diameter of the annular convex portion 54 of the die 42. Therefore, when the support punch 30 is displaced in the direction of arrow Y, the extruded portion 9 b formed apart from the outer peripheral surface of the support punch 30 is narrowed by the reverse tapered surface 56 of the die 42 and the annular convex portion 54. And reduced in diameter. in this case,
The extruded portion 39b of the workpiece 39 is the support punch 3
The outer peripheral surface of the support punch 30 is pressed down in the axial direction of the support punch 30 as in a conventional extrusion molding method in order to further reduce the diameter of the expanded portion. Without contacting the outer peripheral surface thereof, and can be reduced in diameter with a predetermined spacing (see FIG. 3).
The extruded portion 39b of the workpiece 39 is reduced in diameter by the reverse tapered surface 56 and the annular convex portion 54 of the die 42. At this time, the first inner wall surface 50 serves as a flank surface. The diameter can be reduced without causing scratches or the like on the outer peripheral surface of the extruded portion 39b of the object 39.

As described above, the extruded molded product 3
When the support 9 is separated from the support punch 30, a small gap 68a is provided between the inner wall surface of the support punch 30 and the inner wall surface of the molded product 39c, so that the inner wall surface of the molded product 39c is in a non-contact state. Without scratching, etc.
It can be taken out suitably (see FIG. 3).

Next, an extrusion molding apparatus for carrying out the extrusion molding method according to claim 2 of the present invention will be described with reference to FIGS.
Shown in Note that this molding apparatus employs backward extrusion in which a workpiece is extruded in a direction opposite to the method of applying pressure through a punch.

As shown in FIG. 5, the extruder 70 has a support punch 74 for supporting the workpiece 72 and a hole 76 surrounding the workpiece 72 and the side surface of the support punch 74. And a pressing punch 80 for pressing the workpiece 72 toward the support punch 74. In this case, since the support punch 74 is fixed to a support table (not shown), the support punch 74 does not displace. On the other hand, the pressing punch 80 and the die 78 are formed so as to be displaceable in the direction of an arrow under the driving action of a displacement means (not shown). Have been.

The molding device 70 is basically configured as described above, and the operation thereof will be described next. First, as shown in FIG.
The workpiece 72 is arranged at the tip of the support punch 74 in 6. In this case, the workpiece 72 is disposed at a position where the upper surface of the workpiece 72 slightly protrudes from the upper surface of the die 78.
Subsequently, a displacement means (not shown) is driven to press the pressing punch 80.
Is coaxial with the workpiece 72 and is displaced in the direction of the arrow to abut on the upper surface of the workpiece 72. The pressing punch 8
The diameter of 0 is formed smaller than the diameter of the workpiece 72.

Next, after the pressing punch 80 abuts on the workpiece 72, a displacing means (not shown) is driven together with the pressing punch 80 to displace the die 78 in the direction of the arrow. At this time, as shown in FIG. 6, the pressing punch 80 and the die 78 are displaced in a state where the distal end portion of the pressing punch 80 and the upper surface portion of the die 78 maintain a separation distance A in the axial direction. The thickness A of the extruded portion 72a of the workpiece 72 can be adjusted according to the set distance A.

Due to the pressing action of the pressing punch 80, the portion other than the portion where the tip of the pressing punch 80 abuts on the workpiece 72, that is, the upper end of the workpiece 72 is the outer peripheral surface of the pressing punch 80. Extruded in a direction away from In this case, in the extrusion molding according to the prior art shown in FIG. 8, the raised and extruded portion is restricted by the space surrounded by the inner wall surface of the die 2 and the outer peripheral surface of the pressing punch 10, and the outer periphery of the pressing punch 10 Extruded in contact with the surface.

On the other hand, in the present embodiment, the state in which the tip of the pressing punch 80 and the upper surface of the die 78 are separated by the separation distance A is maintained, and the work of pressing the workpiece 72 is performed. . Therefore, as shown in FIG. 5B, the portion 72a extruded by the pressing punch 80 is slightly larger than the inner diameter of the die 78 due to the separation distance A, and is separated from the outer peripheral surface of the pressing punch 80 to form the gap 82. Is extruded. In this case, as shown in FIG. 6, the separation distance A between the distal end portion of the pressing punch 80 and the upper surface of the die 78 with respect to the axial direction, and the axial direction between the outer peripheral surface of the pressing punch 80 and the inner wall surface of the die 78. The direction C orthogonal to the angle θ formed by the separation distance B with respect to the orthogonal direction is the extrusion direction of the extruded portion 72a.

The extruded portion 7 of the workpiece 72
When the thickness D of 2a is relatively thick, it is preferable to regulate the extrusion direction and fix a ring member 84 having a predetermined inner diameter to the upper surface of the die 78 as shown in FIG.
This is because the portion 72a pushed out by the inner peripheral surface of the ring member 84 is restrained and deforms along the inner peripheral surface of the ring member 84.

As described above, in this embodiment, when the pressing punch 80 is separated from the extruded molded product 72c, the pressing punch 80 is defined between the outer peripheral surface of the pressing punch 80 and the inner wall surface of the molded product 72c. Since there is no gap 82, the outer peripheral surface of the pressing punch 80 and the inner wall surface of the molded product 72c do not rub against each other.
2c can be taken out.

In the embodiment described above, cold forging for extruding a workpiece at normal temperature is employed.

[0032]

According to the extrusion molding method and apparatus according to the present invention, the following effects can be obtained.

That is, in the case of front extrusion molding, a gap is defined between the outer peripheral surface of the support punch and the inner wall surface of the workpiece, and the non-contact state is established. Therefore, when the work is separated from the support punch, the outer peripheral surface of the support punch and the inner wall surface of the work do not rub against each other, and there is no such a problem.

This is the same in the backward extrusion molding, and a gap is defined between the outer peripheral surface of the pressing punch for pressing the workpiece and the inner wall surface of the extruded workpiece. It is possible to prevent the occurrence of flaws or the like on the inner wall surface of the object.

As described above, for example, in a case where a hermetic seal is required such as an air cylinder, it is possible to prevent the hermetic seal from being impaired by a flaw in the inner wall surface.

Further, in this case, since the material is less restrained by the pressing punch and the die, the pressing force by the pressing punch can be reduced as compared with the related art. As a result, the durability of the processed product can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an extrusion molding apparatus according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a state where the extrusion operation of the extrusion molding apparatus shown in FIG. 1 has been completed.

FIG. 3 is a longitudinal sectional view showing a state at the time of knockout of the extrusion molding apparatus shown in FIG.

4A to 4C are partial cross-sectional views illustrating an extruded state of the extrusion molding apparatus shown in FIG.

FIG. 5 is a longitudinal sectional view showing an extrusion molding apparatus according to a second embodiment of the present invention, FIG. 5A is a view showing a state before a pressing punch presses a workpiece, and FIG. It is a figure showing the state where a work was extruded with a punch.

FIG. 6 is a view for explaining a separation position between a pressing punch and a die in the extrusion molding apparatus shown in FIG.

7A and FIG. 7B are views in which a ring member for regulating the angle of the extruded portion is provided in the extrusion molding apparatus shown in FIG. 5;

FIGS. 8A and 8B are cross-sectional views showing an extrusion method according to the related art, respectively.

[Explanation of symbols]

 20, 70 ... Extrusion molding device 22 ... Support base 26 ... Cylinder 30, 74 ... Support punch 36 ... Knockout pin 42, 78 ... Die 50 ... Inner wall surface 52 ... Tapered surface 54 ... Annular convex portion 56 ... Reverse taper surface 64, 80 … Pressing punch 68, 68a… Gap 84… Ring member

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-135876 (JP, A) JP-A-63-30143 (JP, A) JP-A-2-187228 (JP, A) JP-A-4- 200946 (JP, A) JP-A-61-253139 (JP, A) JP-A-63-194836 (JP, A) JP-A-6-39472 (JP, A)

Claims (4)

(57) [Claims] 1. A front extrusion molding method for extruding a workpiece in the same direction as a pressing direction, wherein the step of inserting the workpiece into a die, and a step toward a supporting punch supporting the workpiece via a pressing punch. The workpiece is expanded from the inner diameter side of the die to the outer side, and the inner wall surface of the extruded workpiece and the outer peripheral surface of the support punch for supporting the workpiece are pressed. Extruding the workpiece along the axial direction of the support punch while maintaining a state in which a gap is defined between the support punch, displacing the support punch toward the pressing punch side, and moving outward from the inner diameter of the die. An extrusion molding method, comprising: a step of reducing the diameter of a work to be extruded after being extruded toward an inner peripheral surface side of a support punch; and a step of separating a work from the support punch. 2. A backward extrusion method for extruding a workpiece in a direction opposite to a pressing direction, wherein the workpiece is inserted into the die in a state where an upper surface of the workpiece protrudes from an upper surface of the die, and the workpiece is inserted into the die. A step of being supported by a support punch inserted into the inner hole, and, in a state where the workpiece is supported by the support punch, displacing the pressing punch to press the workpiece toward the support punch side A step of displacing the die in the same direction as the pressing direction of the pressing punch while the pressing surface of the pressing punch and the upper surface of the die are maintained at a predetermined separation distance. . 3. The method according to claim 2, wherein the die is displaced in the same direction as the pressing direction in a state where the workpiece is pressed by the pressing punch, so that the die is separated from the outer peripheral surface of the pressing punch. An extrusion molding method comprising a step of regulating an extrusion direction in an extruded portion. 4. An extruding apparatus for extruding a workpiece in the same direction as a direction in which the workpiece is pressed, wherein a through hole is defined, and an inner wall surface of the hole has a substantially identical diameter from an inlet to a lower side. A continuous first inner wall surface, and a tapered surface whose diameter is reduced downward from the end of the first inner wall surface;
An annular convex portion continuing downward from the terminal end of the tapered surface with substantially the same diameter, a reverse tapered surface expanding downward from the terminal end of the annular convex portion, and a downward tapered portion from the terminal end of the reverse tapered surface. A die having a continuous second inner wall surface having the same diameter, a pressing punch for pressing a workpiece inserted into the first inner wall surface of the die downward, and a pressing member pressed by the pressing punch. An extrusion molding apparatus, comprising: a support punch that supports a workpiece.