JP2001239328A - Deep drawing mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deep drawing provided with a blank holder divided into an outer peripheral side and an inner peripheral side to prevent a peripheral edge of a material to be formed from being broken by pressing a blank holder. Provide a mold. SOLUTION: A blank holder 13 is divided into an outer holder 13a on an outer peripheral side and an inner holder 13b on an inner peripheral side, so that the pressure applied to the inner holder is changed, and the blank holder 13 is automatically bent, so that the peripheral edge of the material M is formed. Prevents end breaks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-acting mechanical press, and more particularly, to an apparatus for shearing a metal sheet material and subsequently forming a cylindrical deep-drawing die. The present invention relates to a deep drawing mold including a blank holder divided on an inner peripheral side.

[0002]

2. Description of the Related Art In the can industry, cylindrical deep-drawing containers (hereinafter referred to as "containers")
Call it a cup. ) Is produced, for example, in US Pat.
No. 020670, No. 4248076 and No. 4416
Double-acting mechanical presses with cup forming tools of the type disclosed in US Pat. No. 140 are commonly used. Such a cup forming press has a cup forming tool that performs a shearing process on a metal sheet material for each stroke and then performs a cylindrical deep drawing process. Production requirements in the can industry include increasing the number of production units per hour and reducing costs. The double-acting mechanical press for forming a cup is provided with a cup forming tool that can obtain about 10 cups per stroke, and therefore, the thrust of the press is of the order of 100 tons. Also, in the can industry, this cup is used, for example, in US Pat.
Perform redrawing / ironing as in No. 12 (hereinafter referred to as DI processing) to obtain a deeper metal container. In the case of beverage cans, the diameter of a can body with a large amount of circulation in the market is around 66 mm (commonly called 211 diameter: 2-11 / 16 inches), and the diameter of the cup is 90 mm and the height is around 40 mm Is used. Since such a cup is operated within the range of 150 to 200 strokes / minute, the strokes of the inner ram and the outer ram of the double-acting mechanical press are generally about 5 inches and about 2 inches, respectively. . In the cup processing, a cylindrical product having a bottom surface and side surfaces is obtained using a blank material obtained by punching a metal sheet material by shearing. FIGS. 21 (a), (b) and (c)
Shows a cup forming process using a conventional cup forming tool. The forming die has a punch 1, a die 2, and a blank holder 3, and a blank material M is arranged on the die 2, and a peripheral portion thereof is blanked. While pressing and holding the die 1 with the holder 3 and lowering the blank 1 by lowering the punch 1, the peripheral portion of the pressed and held blank M is slid and fed into the portion to be molded. I'm getting a cup.

[0003]

SUMMARY OF THE INVENTION For example, JP-A-10-1
Two types of cup forming tools introduced in Japanese Patent No. 284777 include one in which no processing is performed on the bottom surface of the cup, and one in which a convex shape is processed on the bottom surface of the cup. An example of a cup which receives a convex processing on the bottom surface of the cup is disclosed in JP-A-7-88580. This is because when the thickness of the blank metal is reduced,
By using a cup having a convex bottom surface, there is an effect that wrinkles are less likely to be generated at the bottom of a metal container (hereinafter referred to as a DI can) obtained by subsequent DI processing. Reducing the thickness of the blank material of the metal container reduces the manufacturing cost, but the amount of material input decreases, so in DI cans, etc., if the thickness of the side wall is not reduced, the container height will be sufficient. Can not be obtained. Reducing the thickness of the container side wall makes it easier for the container side wall to be depressed in the transport equipment, resulting in poor appearance as a product. In particular, in the DI can after the contents are filled, the side wall is particularly likely to be dented. To prevent this, the transport equipment needs to be improved, but this requires a large amount of cost. Therefore,
The manufacturer of the can may change the specifications of the can according to the requirements of the filling manufacturer. However, can manufacturers often respond by changing the forming tool without increasing the number of manufacturing facilities. Therefore, the above-mentioned two types of cup forming tools may be alternately mounted on one double-acting mechanical press.

FIG. 22 shows an example of a cup P obtained by a conventional deep drawing mold. A peak T and a valley V are formed at the peripheral edge. This is because, when a material having anisotropy in a plate surface such as a rolled material is deep drawn by pressing, the peripheral edge of the molded product becomes uneven due to a difference in strength characteristics depending on the rolling direction of the material. In particular, in the cylindrical deep drawing using a thin circular blank material, since the pressing of the blank holder concentrates on the mountain T at the final stage shown in FIG. 21B, the mountain T has a compressive deformation in the material plate pressure direction. The receiving material is crushed and the plate thickness becomes thin. Further, when the blank material M is slid into the shoulder of the die 2 by the punch, the peripheral edge of the blank material is restrained by the thickness of the blank holder, so that the blank material M undergoes tensile deformation in the material radial direction. Since the peripheral edge portion corresponding to is thinner, the portion may be broken. In particular, in a press operated automatically, the fragments at the peripheral edge are caught in the next blank material and damage the next molded product, and the wound may cause the molded product to break. In addition, when redrawing or ironing is performed to make a deeper molded product, the thickness T of the thinned peripheral edge of the blank material obtained by deep drawing is reduced.
May break.

[0005] In deep drawing, it is indispensable to prevent the wrinkles of the molded product by preventing the peripheral portion of the blank material M from being drawn while being pressed by the blank holder 3 and being drawn to the molded portion. However, when the molding process proceeds to the final stage shown in FIG. 21B and the blank holder 3 reaches the stage of pressing only the peripheral edge of the blank material M on the inner peripheral bottom surface, the peripheral end There is no danger of wrinkling if the pressing force is applied to slide the edge part to the shoulder of the die 2 stably, and if the pressing force is suppressed to this extent, the compression in the thickness direction with respect to the peripheral edge part It is considered that deformation can be avoided. In this regard, if the pressure of the blank holder 3 against the peripheral edge of the blank material M is adjusted and weakened at the final stage of the deep drawing forming process,
It should be possible to secure a good molded product without wrinkling and without forming a thin portion at the top of the mountain T at the peripheral edge. However, employing a large-sized mechanism or complicated control for adjusting the pressing force is not preferable in terms of cost and workability. Therefore, the following method has conventionally been used as a simple mechanism that adjusts the pressing of the blank holder 3 and does not crush the peripheral edge of the blank material. First
In the mechanical double-acting press, there is a method using a phase difference between a crank of an inner ram with a die and an outer ram with a blank holder. FIG. 23 shows the timing of the crank of the mechanical double-acting press. By setting the phase of the outer ram ahead of the phase of the inner ram, the outer ram is already at a position higher than the bottom dead center before the inner ram reaches the bottom dead center. By doing so, the blank holder attached to the outer ram is raised immediately before the punch attached to the inner ram slides into the inner diameter of the die, thereby preventing the peripheral edge from being subjected to compression deformation. it can. As a second method, there is a method in which a gap substantially equal to that of the blank material M is provided between the blank holder and the die so that pressing by the blank holder is not applied more than necessary. In this method, the pins 6 as shown in FIG. 24 are provided on the die mounting portion to support the blank holder 3 ′ so that the blank holder 3 ′ is not forcibly lowered. At this moment, the upper pin 6
By sandwiching the remaining portion of the metal sheet, which is a blank material, except for being blanked as a blank, between a and the lower pin 6b, a gap having the same thickness as the blank material is always created. The portion other than the punched portion later becomes scrap and is collected outside the press. However, even if these methods are selected, each cup forming tool that implements a cup that receives no processing on the bottom of the cup and a cup that receives a convex processing on the bottom of the cup is a mechanical double-acting press with the same phase difference. If you try to attach it to: In the first method, if the phase difference of the mechanical double-acting press is matched with a forming tool that does not perform any processing on the bottom of the cup, the punch attached to the inner ram will be used at the bottom dead center of the inner ram. With a forming tool that performs convex processing on the bottom of the cup, the blank holder attached to the outer ram moves up the blank holder long before the punch attached to the inner ram slides into the inner diameter of the die. Insufficient pressing and holding force acts on the material, causing large wrinkles on the side wall of the cup.Before pressing and holding the blank with the blank holder attached to the outer ram, the blank material is pressed by the punch attached to the inner ram. It is impossible to find the optimum range, for example, by slipping the inside of the die into the die and starting the molding, and also forming wrinkles on the side of the cup. In the second method, the optimal timing with the punch 1 'can be found by not forcibly lowering the blank holder 3', but on the other hand, the shearing of the blank material performed before the cup molding is performed. In the processing mold,
It will continue to descend further. Then, the portion of the scrap other than the blank that is punched out as a blank is sandwiched between the lower pin 6b and the stock plate 7 in FIG. 24. However, if the angle θ is large, the scrap warps greatly, and the scrap is conveyed out of the press. It becomes difficult. The present invention has been made in view of such a problem, and an object thereof is to provide a blank holder in a final stage of a deep drawing forming process in which a peripheral edge of a blank material is pressed and held on an inner peripheral bottom surface thereof. An object of the present invention is to provide a deep drawing mold having a simple structure capable of adjusting and weakening the pressing force of a blank holder.

[0006]

The present invention has the following arrangement in order to solve this problem and achieve the object. The invention according to claim 1 is a deep drawing mold having a forming punch, a forming die, and a blank holder for pressing and holding a blank material as a material to be formed between the die and a blank. The holder is divided into an outer holder on the outer peripheral side and an inner holder on the inner peripheral side, and is provided with a plurality of pressurizing means for applying pressure to the outer holder and the inner holder. As described above, by dividing the blank holder into the outer holder on the outer peripheral side and the inner holder on the inner peripheral side, the inner holder for pressing and holding the peripheral edge of the blank material M at the final stage of the molding process is targeted. Adjust the pressing force. Further, by providing a plurality of pressurizing means, the pressing force is adjusted or set by selecting or combining pressurizing means for applying pressure to the inner holder. In addition,
The pressure application by the pressurizing means in the present invention is not limited to the case where the pressure is directly applied to the outer holder or the inner holder, but also includes the case where the pressure is applied to each other via another divided component. The invention according to claim 2 is two fluid pressure cylinders in which the plurality of pressurizing means are connected in series, and a piston is fitted to one of the cylinders with its end extended to the other cylinder. At the same time, the piston of the other cylinder is constituted by dividing the blank holder by the outer holder and the inner holder, and the outer holder is located covering the outer periphery of the inner holder, and the upper surface of the convex part provided on the inner peripheral part is The piston is fitted on the lower surface of the convex portion provided on the outer peripheral portion of the inner holder, and the end of the piston fitted to the one cylinder is in contact with the upper surface of the inner holder. With this configuration, the pressurizing means (fluid pressure cylinder) that applies pressure to each of the outer holder and the inner holder is separated, and the pressure applied to the inner holder is also applied to the outer holder via the inner holder. On the other hand, the pressure applied to the outer holder is not transmitted to the inner holder, and the pressing force of the inner holder is set smaller than that of the outer holder. Claim 3
The described invention is two fluid pressure cylinders in which the plurality of pressurizing means are connected in series, and a piston is fitted on one of the cylinders with its end extended to the other cylinder, and the other is mounted on the other cylinder. The piston of the cylinder is divided into a blank holder by an outer holder and an inner holder, and the piston is fitted in one cylinder with its end extended to the other cylinder, and the outer holder is The upper surface of the inner peripheral portion is located in contact with the lower surface of the flange provided on the outer peripheral portion of the inner holder, and the end of the piston fitted to the one cylinder is in contact with the upper surface of the inner holder. Features. With this configuration, when the outer holder presses and holds the peripheral portion of the blank material, all the pressures of the plurality of pressing means are applied to the outer holder via the inner holder, and the blank material is formed. When the outer holder descends by the thickness of the blank material when it is pulled by the outer holder and the outer holder descends by the thickness of the blank material, a part of the supply pressure to the inner holder is lost due to the gap created between the outer holder and the inner holder. Thus, the pressing force on the blank material is reduced. The invention according to claim 4 is a blank holder composed of an outer holder and an inner holder for pressing and holding the blank material as the material to be formed between a molding die and pressing the material to be formed. The diameter ratio between the outer holder and the inner holder is 1.0: 0.65
8 to 0.839. With such a configuration, the cup side wall is less wrinkled and the cup can be used. In the invention according to claim 5, the innermost peripheral portion of the wrinkle suppressing surface of the outer holder is:
It is characterized in that it has a required length several times the diameter of the material to be molded and has a step. With this configuration, no scratch is generated on the side wall of the cup, and no wrinkles are generated. In the invention according to claim 6, the outermost peripheral portion of the wrinkle suppressing surface of the inner holder is:
It has a radius of 0.5 times or more of the material to be molded, and has an angle of 0 to 20 degrees with respect to the wrinkle suppressing surface in contact with the radius,
A radius connecting the angle and the wrinkle suppressing surface is at least 0.5 times the thickness of the material to be molded, and the outermost length is 0.001 to 0.005 of the material to be molded. . With this configuration, no scratch is generated on the side wall of the cup, and no wrinkles are generated. In the invention according to claim 7, the length of a portion different from the same plane with respect to a wrinkle suppressing surface formed by a gap in a divided portion of the outer holder and the inner holder is 0.006 to
It has a length of 0.02 times. With this configuration, the effect of preventing pitching can be obtained, and wrinkles do not occur. The invention according to claim 8 is characterized in that the wrinkle suppressing surfaces of the outer holder and the inner holder have a shape of a plurality of irregularities, and when the one closer to the vertical distance with respect to the molding die is convex, Is 1.5 to 5.0 of the thickness of the material to be molded.
And the ratio of the length of the irregularities in the radial direction is 1.0:
1.4 to 3.4, and the depth of the concave portion is 0.1 to 0.7 times the thickness of the material to be formed with respect to the surface of the convex portion, and the transition from the concave portion to the convex portion is performed. The part is 3.0 with respect to the horizontal plane of the convex part.
It is characterized by having a tangent of up to 20 degrees and a radius of 0.4 to 4.0 times the material to be molded. With this configuration, the wrinkle suppressing force is reduced, and pitching can be reduced. According to a ninth aspect of the present invention, a portion having a length of 0.003 to 0.02 times the diameter of the material to be molded, which is inside the radius start position of the molding die facing the inner holder, is formed on the molding die. Then, the formed 0.003-0.
02, a step of 0.4 to 0.6 times the plate thickness is formed in the inner holder corresponding to the length of 02, and the wrinkle suppressing surface of the inner holder and the step transition portion are 0.5 mm of the material to be molded.
It is characterized in that at least a portion serving as an ear of the cup is provided with a relief portion having a radius of twice or more and an angle of 10 to 30 degrees with respect to the wrinkle suppressing surface. With this configuration, no wrinkles occur at the tip of the cup, and there is no fear of scratching the surface of the cup.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
Description will be given based on the drawings. FIG. 1 is a partial sectional view showing an embodiment of the deep drawing mold according to the present invention. The forming die according to the present embodiment has a forming punch 11 and a die 12 and a blank holder 13 for pressing the blank material M, similarly to a normal deep drawing forming die. However, in the present embodiment, the outer holder 13a on the outer peripheral side and the inner holder 13 on the inner peripheral side where the blank holder 13 is divided are configured.
b, and two air cylinders 14 are provided as pressure means for applying pressure to the outer holder 13a and pressure means for applying pressure to the inner holder 13b. The pressure means for applying pressure to the inner holder 13b is an inner cylinder. Outer holder 13 via holder 13b
The pressure means for applying pressure to the outer holder 13a and applying pressure to the outer holder 13a does not apply pressure to the inner holder 13b.

Hereinafter, the present embodiment will be described in detail with reference to FIGS. The cylinder 14 in the present embodiment is an annular cylindrical cylinder provided with a through-hole H through which the punch 11 is slidably inserted in the axial direction of the center portion. A partition 14a leaving a gap on the side is provided to partition an upper first cylinder R1 and a lower second cylinder R2, which are two pressurizing means, and an air inlet 14b is provided at an upper outer peripheral position of each of the cylinders R1 and R2. Is arranged. In addition, the lower end of the inner peripheral side of the cylinder 14 is cut out in an annular shape, and a bottom surface 14c that is folded in the inner peripheral direction from the lower end edge of the outer peripheral side is provided.
An annular opening W connected to the notch is formed.

A cylindrical piston 15, which is pressed down by air pressure and descends, is air-tightly fitted in the first cylinder R1 in the upper part of the hollow portion of the cylinder 14, and the lower end thereof is provided with a gap on the inner peripheral side of the partition wall 14a. The second cylinder R2 reaches the lower second cylinder R2 and contacts the upper surface of an inner holder 13b described later. A blank holder 13 divided by an outer holder 13a and an inner holder 13b is hermetically sealed in the second cylinder R2 below the hollow portion of the cylinder 14 as a piston whose lower end bottom surface is exposed to the opening W of the cylinder 14. And the configuration is as follows. That is, the inner holder 13b is a cylindrical body having an inner diameter compatible with the through-hole H of the cylinder 14, and having an outer diameter compatible with the outer diameter of the piston 15, and having an annular convex portion on the outer peripheral portion,
The upper end face is fitted so as to close the cutout portion at the lower end on the inner peripheral side of the cylinder 14 in a state of contacting the bottom surface of the piston 15. The other outer holder 13a
A cylindrical body having an inner diameter compatible with the outer diameters of the piston 15 and the inner holder 13b, and having an outer diameter portion in contact with the outer periphery of the hollow portion of the second cylinder R2, the upper surface of a convex portion provided on the inner periphery thereof; Is brought into contact with the lower surface of the convex portion of the outer peripheral portion of the inner holder 13b, and is fitted so as to hermetically cover the outer peripheral surface of the inner holder 13b over the contact position with the piston 15.

The molding die according to the present embodiment has the above configuration, and the first cylinder R1 serving as one of the pressing means presses the inner holder 13b abutting on the bottom surface thereof via the piston 15. At the same time, the pressure is also transmitted to the outer holder 13a in which the upper surface of the inner convex portion abuts the lower surface of the outer convex portion of the inner holder 13b. On the other hand, the second cylinder R2 is the outer holder 1
It pushes only 3a and does not reach the inner holder 13b hermetically covered with the outer holder 13a.

The process of deep drawing using this mold is as follows.
As shown in FIG. FIG. 3A shows a state at the start of molding. The cylinder 14 is positioned on the blank material M placed on the die 12, and air is injected through the injection port 14b. At this time, both the outer holder 13a and the inner holder 13b press and hold the peripheral portion of the blank material M on the die 12, but the blank material M is the first material.
Both the cylinder R1 and the second cylinder R2 are strongly pressed by the outer holder 13a supplied with air pressure. Under this pressure, the punch 11 is moved down to push down the blank material M and pull the peripheral portion thereof toward the forming portion, thereby ensuring good forming without wrinkling. Subsequently, when the punch 11 is further lowered by further forming, the blank material M pulled in the direction of the forming portion slides and separates between the outer holder 13a and the die 12, and the peripheral edge portion of the blank material M is removed only by the inner holder 13b. To the end of the molding process. FIG. 3B shows this stage in the molding process. At this time, the peripheral edge of the blank material M stops receiving only a weak pressure from the inner holder 13b given only the air pressure of the first cylinder R1.
Compressive deformation of the peripheral edge of the blank material M at the final stage of molding can be avoided. As a result, the compressive deformation and the tensile deformation applied to the peripheral edge portion of the blank material M are alleviated, so that the problem that the mountain T 'of the cup P' obtained by molding is greatly crushed and breaks, etc. is solved. be able to. In addition, the change of the pressing force by the blank holder 3 is ensured in a timely and automatic manner by the movement of the blank material M accompanying the molding.
It is sufficient that the air pressures of the first and second cylinders R2 are kept constant, and no complicated adjustment / control and no equipment / device for the adjustment are required. The outer holder 13a
As shown in FIG. 3C, when the blank material M is released from the pressing, the blank material M is lowered by the thickness of the blank material M and the horizontal position of the bottom surface is different from that of the inner holder 13b. Then, all the blank material M is fed into the molding portion, thereby returning to the same horizontal position, so that the next molding operation can be performed.

FIG. 4 is a partial sectional view showing a schematic configuration of another embodiment of the deep drawing mold according to the present invention. The molding die according to the present embodiment also includes a punch 21, a die 22, and a blank holder 23 as in the above-described embodiment, and is configured so that the blank holder 23 can be divided by an outer holder 23a on the outer peripheral side and an inner holder 23b on the inner peripheral side. ,
This is airtightly fitted as a piston to the air cylinder 24. However, in this embodiment, when the outer holder 23a presses and holds the blank material, the two pressurizing means of the air cylinder 24 apply pressure to the inner holder 23b and also apply pressure to the outer holder 23a via the inner holder 23b. When pressure is applied and the blank material is released from the pressing of the outer holder 23a and only the inner holder 23b is pressing and holding the blank material, a part of the pressure applied to the inner holder 23b from the plurality of pressing means is reduced. It is configured to be eliminated or cut off. That is, when compared with the above-described embodiment, in the present embodiment, the air cylinder 24
Are not divided into a pressing means for applying pressure to the inner holder 23b and a pressing means for applying pressure to the outer holder 23a, and the aforementioned embodiment applies a low pressure to the inner holder 23b throughout the entire molding process. On the other hand, in the present embodiment, when the blank material moves and releases the pressing of the outer holder 23a, the inner holder 2
The difference is that the pressing force of 3b is changed to be low.

Hereinafter, the present embodiment will be described with reference to FIG. 4. The cylinder 4 is the same as the above-described embodiment, and has two pressing means, a first cylinder R1 and a second cylinder R2. The first cylinder R1 has a piston 2
5 is hermetically fitted with its lower end extended to the second cylinder R2. Also, the second cylinder R2
Has an outer holder 23a and an inner holder 23
The blank holder 23 divided by b is fitted airtightly with its bottom surface exposed to the opening W of the cylinder 24, and the configuration is as follows. That is, the inner holder 23b is a cylindrical body having an upper step inner diameter adapted to the inner periphery of the second cylinder R2 hollow part and a lower step inner diameter adapted to the through hole H of the cylinder 24, and an annular convex at the upper end part outer periphery. And an annular concave portion is provided on the outer periphery of the lower end portion. The other outer holder 23a is a cylinder having an outer diameter portion that matches the outer periphery of the hollow portion of the cylinder 4,
An annular projection is provided on the inner periphery of the lower end. Both of the upper surfaces of the inner peripheral portion of the outer holder 23a are attached to the inner holder 23b.
The blank holder 23 is brought into contact with the lower surface of the projection provided on the outer periphery of the upper end, and the projection on the inner periphery of the lower end of the outer holder 23a is fitted into the recess of the inner holder 23b.
And the upper surface of the inner holder 23b is fitted to the second cylinder R2 with the upper surface of the inner holder 23b contacting the piston 25 extending from the first chamber.

The molding die according to the present embodiment has the above configuration, and FIG. 5 shows a molding process using this molding die. FIG. 5A shows a state at the start of molding, in which a cylinder 24 is brought into contact with a blank material M placed on a die 22, and air is injected through an injection port 24b. The air pressure of the first chamber R1 presses the inner holder 23b which comes into contact with the piston 25 via the piston 25, and makes the upper surface of the inner peripheral portion abut the lower surface of the annular convex portion provided on the outer periphery of the upper end of the inner holder 23b.
The pressure is transmitted to and pressed against the outer holder 23a fitted to the concave groove portion b. Also, the second cylinder R
The air pressure of No. 2 presses the annular convex portion of the inner holder 23b to apply pressure to the inner holder 23b, and also applies pressure to the outer holder 23a via the contact portion. Thus, the outer holder 23
In the molding stage where a is pressing and holding the blank material M, 2
The air pressure of the first cylinder R1 and the second cylinder R2, which are two pressing means, is applied to both the outer holder 23a and the inner holder 23b to strongly press the peripheral edge of the blank material M. A desired molded product without wrinkles is secured by pulling in the direction of the molded portion. When the molding work is further advanced, the blank material M
Comes off from the space between the outer holder 23a and the die 22 in the direction of the molding portion, and the peripheral edge thereof is
It reaches the molding final stage where only b presses. FIG. 5B shows this stage. As shown, the outer holder 2
When the lower portion 3a descends on the die 22 and takes a different horizontal position from the bottom surface of the inner holder 23b that presses the peripheral edge of the blank material M, the inner holder 23b that has come into contact with the inner holder 23b
A gap S is formed between the lower surface of the convex portion on the outer periphery of the upper end portion and the upper surface of the inner peripheral portion of the outer holder 23a, and the air injected into the second cylinder R2 flows into the gap S. As a result, the air pressure is applied from both the upper and lower surfaces of the convex portion of the inner holder 23b and is offset, and the piston 25 is attached to the inner holder 23b.
Only the air pressure from the first cylinder R1 via Thus, according to the present embodiment,
When the forming process proceeds and the peripheral edge of the blank material M reaches the final stage in which the blank is pressed and held only by the inner holder 23b, the pressing force applied to the blank material M is given by the two pressing means R1 and R2. The pressure is reduced to the pressure of only one pressurizing means R1. As a result, the compressive deformation and the tensile deformation applied to the peripheral edge portion of the blank material M are alleviated, so that the problem that the mountain T 'of the cup P' obtained by molding is greatly crushed and breaks, etc. is solved. be able to. As shown in FIG. 5 (c), when all of the blank material M is pulled and fed into the molded portion, the outer holder 23a and the inner holder 23b return to the same horizontal position on the die 22, and the two are separated by two. The next molding operation can be immediately performed in a state where the same pressure is applied from the pressurizing means.

As described above, in this embodiment, the pressure applied to the inner holder 23b (in other words, the pressing force applied to the blank material M) is changed, but the change is caused by the mutual positional relationship between the outer holder 23a and the inner holder 23b. , And is inevitably generated with the progress of the forming process due to the movement of the blank material. Therefore, even in the case of the present embodiment, the first
The air pressures of the cylinder R1 and the second cylinder R2 may be kept constant, and no complicated adjustment / control and no equipment / device for it are required.

Further, when the cup is formed by the deep drawing molds of the above two embodiments, the blank material is not a perfect circle, and the diameter of the peak portion of the peripheral edge of the cup is reduced in advance. If a material is used, a better cup can be formed. In other words, a non-circular blank material in which the diameter of the peak portion in the original material characteristics is reduced,
At the time of passing the outer holder, the large diameter part undergoes compressive deformation in the thickness direction to grow a slight mountain, and just before passing the inner holder, the mountain part whose diameter is reduced is also the material characteristic At the same time, the peripheral edge of the blank material has a substantially uniform diameter when passing through the inner holder. As a result, as shown in FIG. 6, a cup P 'having a small peak T' at the peripheral edge and having a substantially uniform height is obtained. In addition, since the blank holder is divided by the outer holder and the inner holder, the diameter difference between the peak portion of the peripheral edge of the cup and the other portion is not large, and the non-circular shape close to a perfect circle is not enough. It is possible to obtain a cup having a blank edge and a peripheral edge having a substantially uniform height.

By dividing the blank holder into the outer holder and the inner holder as described above, a cup having a substantially uniform height at the peripheral edge of the cup can be obtained. By applying pressure by the pressing means, the pressing force against the material to be molded is reduced, and the compressive deformation and tensile deformation of the blank material at the peripheral edge of the material to be molded are reduced. However, by dividing the blank holder or providing a plurality of pressurizing means and setting the sizes of the outer holder and the inner holder, wrinkles generated on the side wall of the cup are prevented. There is a deep drawing mold. That is, in FIG. 1, the diameter ratio between the outer holder 13a and the inner holder 13b that presses the molding material M is 1: 0.658 to
When it is set to 0.839, the occurrence of wrinkles on the side wall of the cup obtained by molding is small, and a usable cup can be obtained.

FIGS. 7 and 8 show a case where a step is formed on the outer holder 13a. The length L of the outer holder 13a is set to 0.005 to 0.015 times the diameter D of the material to be molded. As shown in FIGS. 7 and 8, the length L is 0.0 mm of the material D to be molded.
If the magnification is less than 05 times, a pinching phenomenon occurs in which the tip of the cup is formed at an acute angle as shown in FIG. This pinching adversely affects the cup by damaging the tip of the cup. This pinching phenomenon is caused by the fact that, if the distance is insufficient, the hill portion of the cup has already passed through the valley before reaching the step (described later) in contrast to the anisotropy of the material to be molded. This is because there is a case that it is done. When the length L of the outer holder 13a exceeds 0.015D, wrinkles and scratches occur at the tip of the cup. The reason why the wrinkles and scratches are generated is that the wrinkle suppressing force is reduced at the escape portion of the step, and large wrinkles are generated when the area is large. (It does not disappear even if it passes through the inner holder). In addition, this is because the wrinkles are caught on the entry side of the inner holder 13b, so that scratches are easily generated. That is, the diameter ratio between the outer holder 13a and the inner holder 13b is 0.846, assuming that the outer holder 13a is 1, as shown in FIG.
0.839, 0.826, 0.790, 0.726,
The range of 0.658 is optimal.

In FIG. 7, the outer holder 13
The step s is formed by increasing the step angle by 10 to 30 ° from the pressing surface f holding the molding material a in FIG. This step s is 0.4 to 0.6 times the thickness t of the material to be molded. If the step s is smaller than 0.4 times the plate thickness t, the pinching phenomenon occurs at the tip of the cup. The reason why the pinching phenomenon occurs is that if the clearance of the step is narrow, the effect of the present shape is difficult to appear. When the step s exceeds six times the thickness t of the material to be molded, wrinkles and scratches occur at the tip of the cup. The reason for the occurrence of the wrinkles and scratches is that if the clearance of the step s is wide, the wrinkles cannot be sufficiently suppressed and the wrinkles grow even after passing through the inner holder 13b, and the wrinkles are caught on the entrance side of the inner holder 13b, This is because scratches are likely to occur. If the step angle θ is smaller than 10 °, a pinching phenomenon occurs at the tip of the cup. The reason for this pinching phenomenon is that
If the angle is small, the distance between the flat steps will be shorter,
This is because the effect of this shape is reduced. If the step angle θ is larger than 30 °, wrinkles and scratches occur at the tip of the cup. The reason for the occurrence of such wrinkles and scratches is that when the wrinkles are released rapidly, large wrinkles occur. This wrinkle remains even after passing through the inner holder. In addition, the wrinkles are caught on the entry side of the inner holder 13b, and scratches are likely to occur. A curved surface R is formed at the rising start end rising from the wrinkle suppressing surface f. This curved surface R is set to be 0.6 times or more the thickness t of the material to be molded. If this curved surface is less than 0.6 times, the side wall of the cup may be damaged. This is because the curved surface R that is too small scratches the surface of the cup material.

FIGS. 11 and 12 show the shape of the inner holder 13b. Radius R1, R2 of the outermost periphery of the wrinkle suppressing surface of this inner holder 13b
Is set to be 0.5 times or more the thickness t of the material to be molded. The reason for this is that if R1 and R2 are too small, the surface of the cup material will be scratched. Further, the angle θ is set to 0 to 20 ° with respect to the wrinkle surface in contact with the radius. This θ is set to 0
The reason why the angle is set to ２０20 ° is that if θ is set to be more than 20 °, the wrinkle suppressing force is reduced and large wrinkles are generated. The length L of the outermost periphery of the wrinkle suppressing surface is set to 0.001 to 0.005 times the diameter D of the material to be molded. If L is set to less than 0.001, the radius of R becomes small because a sufficient distance cannot be obtained, and as a result, the surface of the cup material is scratched. Alternatively, when L is set to be more than 0.005 times, the distance is too long, so that the wrinkle suppressing force is reduced and large wrinkles are generated. FIG.
3 is a result of an experiment in which L and θ were changed. FIG. 14, FIG.
5 shows the shape of the wrinkle suppressing surfaces of the outer holder 13a and the inner holder 13b. The length L consisting of the innermost peripheral part m of the outer holder 13a, the outermost peripheral part n of the wrinkle suppressing surface of the inner holder 13b, and the gap d between the outer holder 13a and the inner holder 13b is the diameter D of the material to be molded. 0.006
It is set to ~ 0.002 times. If the length L is less than 0.006 times D, a pinching phenomenon occurs at the cup tip. The reason why this pinching phenomenon occurs is that the pinching prevention effect of the present shape cannot be obtained unless a sufficient distance is taken. L is 0.02 of D
If it exceeds twice, wrinkles occur at the cup tip. The reason for the occurrence of the wrinkles is that if L is set too long, the wrinkle suppressing force decreases.

FIGS. 16 (a), 16 (b), and 17 show the case where the outer holder 13a or the inner holder 13b has an uneven portion formed on the wrinkle suppressing surface. The concave and convex portions are convex in a direction close to the vertical distance with respect to the forming die. At this time, assuming that the length of the convex in the radial direction is 1, the length of the concave in the radial direction has a ratio of 1.4 to 3.4 times. The depth of the concave portion is 0.1 to 0.7 times the thickness of the material to be formed with respect to the surface of the convex portion, and the transition from the concave portion to the convex portion is relative to the horizontal plane of the convex portion. θ3.0-
It has a tangent of 20 ° and at the same time, the thickness t of the material to be molded is 0.
It is designed to have a radius of 4 to 4.0 times. The length L of the projection is 1.5 to 5 times the thickness of the material to be molded. If the length L of the convex portion is less than 1.5t, the cup side wall is damaged. The reason for the occurrence of this scratch is that the distance of the wrinkle suppression becomes too short, and when moving to the next concave part without fully suppressing the wrinkle, a large wrinkle is eventually generated, and the wrinkle is on the side where the convex part enters And the cup side wall is scratched. If L exceeds 0.5t, wrinkles occur on the cup side wall. The reason why this wrinkle occurs is that when the distance between the convex portions is long, when the wrinkle suppressing force is constant, the wrinkle suppressing surface pressure (= wrinkle suppressing force / projection area) generated on the blank material becomes low. This is because wrinkles are likely to occur as a result. If the angle θ is less than 3 degrees, a pinching phenomenon occurs at the tip of the cup. This pinching phenomenon
This is because if the angle is small, the effect of the present shape is reduced. If θ exceeds 20 °, wrinkles occur at the tip of the cup. This is because when these wrinkles are released rapidly, large wrinkles occur. A curved surface R is formed at the beginning of the concave portion. This R is set to 0, 5 or more times the plate pressure t of the material to be molded. If this curved surface is less than 0.5 times, a pinching phenomenon occurs at the tip of the cup. This pinching phenomenon indicates that too small R will scratch the surface of the cup material. The concave portion formed in the outer holder 13a or the inner holder 13b intentionally generates small wrinkles in the material to be formed in the concave portion,
By causing the wrinkles to be hooked at the projection transition portion and generating an appropriate tensile force on the material to be molded, it is possible to prevent the occurrence of large wrinkles as a result. Also, the wrinkle suppressing force of the outer holder and the inner holder can be reduced to a maximum of 1/3 as compared with the conventional method. As a result, not only can pinching be reduced, but also the load on the press can be reduced, and the life of the press can be extended. FIG. 18 shows the results of an experiment in which the values of L, unevenness, s, and θ were variously changed.

FIGS. 19 and 20 relate to the shape of the inner holder 13. It is located inside the radius start position of the forming die 2 facing the inner holder 13b, and has a diameter of 0,003 to 0.
A portion L having a length of 02 times is formed on a forming die. This L
Is less than 0.003 times the diameter D of the material to be molded, a pinching phenomenon occurs at the tip of the cup. This pinching phenomenon is that if the distance is insufficient for the anisotropy of the material, the valley already passes through the forming die radius before the peak of the cup reaches the step difference (described later). This is because there is a case where it is done. L is 0. 0 of diameter D of the material to be molded.
If it exceeds 02, wrinkles occur at the cup tip. This is because the wrinkle suppressing force is reduced at the escape portion (described later), and as a result, wrinkles are generated at the tip of the cup.
0.0003 to 0.02 formed on the molding die 2
Is formed on the wrinkle suppressing surface of the inner holder corresponding to the length L of 0.4 to 0.6 times the plate thickness t. If the step s is less than 0.4 times the plate thickness t, a pinching phenomenon occurs at the tip of the cup. The reason for this pinching phenomenon is that if the clearance of the step is narrow, the effect of this shape is unlikely to appear. When the step s exceeds 0.6 times the plate thickness t, wrinkles occur at the cup tip. This is because wrinkles occur when the clearance of the step is wide. The wrinkle suppressing surface and the step transition portion of the inner holder have a radius R having 0.5 times or more of the plate thickness and a relief portion having an angle θ of 10 to 30 ° with respect to the wrinkle suppressing surface, at least with the ears of the cup. Is provided in the area where The radius R
If the thickness is less than 0.5, the cup side wall will be damaged. The reason for the generation of this scratch is that too small R scratches the surface of the cup material. If the angle θ is less than 10 degrees, a pinching phenomenon occurs at the tip of the cup.
The reason for this pinching phenomenon is that if the angle is small, the distance between the flat steps is short, and the effect of the present shape is reduced. If θ exceeds 30 degrees, wrinkles occur at the tip of the cup. This is because if the wrinkles are released rapidly, the wrinkles will be large.

[0023]

Since the present invention is configured as described above, the following effects can be obtained. (1) According to the first aspect of the present invention, since the blank holder is divided and a plurality of pressurizing means are provided, the pressurizing means for applying pressure is selected or combined, and the pressure on the inner holder is set or changed. Thus, in the forming stage in which the blank is pressed only by the inner holder as the forming process proceeds, the pressing force on the blank can be automatically reduced. Further, by using a non-circular blank material in which the diameter of the peak portion is slightly reduced in the material characteristics, a cup having a small peak and a substantially uniform height at the peripheral edge can be obtained. (2) According to the second aspect of the present invention, the pressure applied to the inner holder is transmitted to the outer holder, while the pressure applied to the outer holder is not transmitted to the inner holder. Since the pressure applied to the inner holder is set to be smaller than that in the forming step, the blank material is pressed only by the inner holder as the forming process proceeds.
The pressing force applied to the blank material can be automatically reduced while maintaining the pressure transmitted from the pressing means to the inner holder constant. (3) According to the third aspect of the invention, when the outer holder is pressing and holding the blank, all the pressure of the pressing means is applied, the blank releases the pressing of the outer holder, and the outer holder descends. When the pressure is applied, the pressure applied by the pressurizing means is kept constant because a part of the supply pressure to the inner holder is eliminated by using the gap inevitably generated at the contact part between the outer holder and the inner holder. While changing the pressure applied to the inner holder as the molding process progresses,
The pressing force received by the blank material can be automatically reduced. (4) The invention according to claim 4 is a blank holder comprising an outer holder and an inner holder for pressing and holding the blank material as the material to be formed between a molding die and pressing the material to be formed. The diameter ratio of the outer holder and the inner holder is 1.0: 0.6
Since it is 58 to 0.839, wrinkles are less likely to occur on the cup side wall, and the cup is usable. (5) In the invention according to claim 5, the innermost peripheral portion of the wrinkle suppressing surface of the outer holder has a length several times as large as the diameter of the material to be molded, and is provided with a step. No scratches occur on the side wall of the cup, and no wrinkles occur. (6) The invention according to claim 6 is that the outermost peripheral portion of the wrinkle suppressing surface of the inner holder has a radius of 0.5 times or more of the material to be molded, and the wrinkle suppressing surface in contact with this radius. The angle connecting the wrinkle suppressing surface with this angle is 0.5 times or more the thickness of the material to be molded, and the outermost length is 0.001 of the material to be molded. Since it is set to 0.005, no scratch is generated on the side wall of the cup, and no wrinkles are generated. (7) The invention according to claim 7, wherein the outer holder has a shape comprising the innermost peripheral portion of the wrinkle suppressing surface of the outer holder and the outermost peripheral portion of the wrinkle suppressing surface of the inner holder. The length of the part different from the same plane with respect to the wrinkle suppressing surface formed by the gap in the divided part of the holder and the inner holder is configured to have a length of 0.006 to 0.02 times the material to be molded, so that pitching is performed. , And wrinkles do not occur. (8) In the invention described in claim 8, the wrinkle suppressing surfaces of the outer holder and the inner holder are formed in a plurality of irregularities, and a portion closer to a vertical distance to the molding die is convex. In this case, the length of the convex in the radial direction is 1.5 to 5.0 of the plate thickness of the material to be molded, and the ratio of the length of the convex to concave in the radial direction is 1.0: 1.4 to 3.4. And the depth of the concave portion is 0. 3 of the thickness of the material to be formed with respect to the surface of the convex portion.
The transition portion from the concave portion to the convex portion has a tangent of 3.0 to 20 degrees with respect to the horizontal plane of the convex portion, and 0.4 to 4.0 times the material to be molded. Since it has a configuration having a radius, a small wrinkle is intentionally generated in the material to be formed in the concave portion formed by the outer holder or the inner holder, and the wrinkle is hooked at the transition portion of the concave portion to generate an appropriate tensile force in the material to be formed. As a result, generation of large wrinkles can be prevented. Also, the wrinkle suppressing force of the outer holder and the inner holder can be reduced to a maximum of 1/3 as compared with the conventional method. As a result, not only can pinching be reduced, but also the load on the press can be reduced, and the life of the press can be extended. (9) The ninth aspect of the present invention is to form a portion having a length of 0.003 to 0.02 times the diameter of the material to be formed, which is inside the radius start position of the forming die facing the inner holder. Formed in a die, this molded 0.003 ~
A step having a thickness of 0.4 to 0.6 times the plate thickness is formed in the inner holder corresponding to the portion having a length of 0.02, and the wrinkle suppressing surface of the inner holder and the step transition portion are formed in the inner holder at 0. 5 times or more radius and 10 to the wrinkle suppressing surface
Since the escape portion having an angle of 30 degrees is provided at least as a portion serving as an ear of the cup, wrinkles do not occur at the tip of the cup, and there is no fear of scratching the surface of the cup.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a cylinder in the embodiment.

FIG. 3 is an explanatory diagram of a main part showing a molding process in the embodiment.

FIG. 4 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of a main part showing a molding process in the same embodiment.

FIG. 6 is an explanatory view showing a molded product by a deep drawing mold according to the present invention.

FIG. 7 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram of a pinching phenomenon occurring in a material to be molded.

FIG. 10 is an explanatory diagram of an experimental study result of a deep drawing mold according to an embodiment of the present invention.

FIG. 11 is an explanatory diagram illustrating a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 13 is an explanatory diagram of an experimental result of a deep drawing mold according to an embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 15 is an explanatory view showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 16 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 17 is an explanatory diagram illustrating a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 18 is an explanatory diagram of an experimental result of a deep drawing mold according to an embodiment of the present invention.

FIG. 19 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 20 is an explanatory diagram showing a schematic configuration of a deep drawing mold according to an embodiment of the present invention.

FIG. 21 is a cross-sectional view showing a schematic configuration of a conventional deep drawing mold.

FIG. 22 is a schematic explanatory view showing a molded product of a conventional deep drawing mold.

FIG. 23 is a graph showing a crank timing of a conventional mechanical double-acting press.

FIG. 24 is a cross-sectional view showing a schematic configuration of another conventional deep drawing mold.

[Explanation of symbols]

 1, 1 ', 11, 21 Punch 2, 2', 12, 22 Die 3, 3 ', 13, 23 Blank holder 13a, 23a Outer holder 13b, 23b Inner holder 14, 24 Cylinder 15, 25 Piston M Blank material

Claims (9)

[Claims] 1. A forming punch, a forming die,
In a deep drawing mold having a blank holder that presses and holds a blank material as a molding material between the molding die, the blank holder is configured by an outer holder on an outer peripheral side and an inner holder on an inner peripheral side. A deep drawing mold, comprising: a plurality of pressurizing means for applying pressure to the outer holder and the inner holder. 2. A plurality of pressure means are connected to each other in two fluid pressure cylinders, and a piston is fitted in one of the cylinders with its end extended to the other cylinder. The piston of the cylinder is configured by dividing the blank holder by the outer holder and the inner holder, and the outer holder is located covering the outer periphery of the inner holder, and the upper surface of the convex provided on the inner periphery is
2. An end of a piston fitted to one of the cylinders is in contact with an upper surface of the inner holder, the end being in contact with a lower surface of a convex portion provided on an outer peripheral portion of the inner holder. Deep drawing mold. 3. A plurality of hydraulic cylinders connected to the plurality of pressurizing means, wherein a piston is fitted in one of the cylinders with its end extended to the other cylinder. The piston of the cylinder is constituted by dividing a blank holder by an outer holder and an inner holder, and the outer holder is positioned by bringing an upper surface of an inner peripheral portion thereof into contact with a lower surface of a flange surface provided on an outer peripheral portion of the inner holder. The deep drawing mold according to claim 1, wherein an end of the piston fitted to one of the cylinders is in contact with an upper surface of the inner holder. 4. A blank holder comprising an outer holder and an inner holder for pressing and holding a blank material as a molding material between a molding die, and an outer holder pressing the molding material. The diameter ratio of the inner holder is 1.0: 0.658 to 0.83
The deep drawing mold according to any one of claims 1 to 3, wherein 5. An innermost peripheral portion of a wrinkle suppressing surface of the outer holder has a length several times a diameter of the material to be molded, and has a step. 4
The deep drawing mold according to any one of the above. 6. The outermost peripheral portion of the wrinkle suppressing surface of the inner holder has a radius of 0.5 times or more of the material to be molded, and has an angle of 0 to 20 degrees with respect to the wrinkle suppressing surface contacting this radius. The radius connecting the angle and the wrinkle suppressing surface is 0.5 times or more the thickness of the material to be molded, and the outermost length is 0.001 to 0.005 of the material to be molded. The deep drawing mold according to any one of claims 1 to 5, characterized in that: 7. The length of a portion different from the same plane with respect to a wrinkle suppressing surface formed by a gap in a divided portion of the outer holder and the inner holder is 0.006 to
6. The structure of claim 5, wherein the length is 0.02 times.
Or a deep drawing mold according to 6. 8. A wrinkle suppressing surface of the outer holder and the inner holder has a plurality of irregularities,
When the one closer to the vertical distance with respect to the molding die is convex, the length of the convex in the radial direction is 1.
5 to 5.0, and the ratio of the length in the radial direction of the unevenness is 1.0: 1.4 to 3.4, and the depth of the recessed portion is smaller than the surface of the projected portion. The transition from the concave portion to the convex portion has a tangent of 3.0 to 20 degrees with respect to the horizontal plane of the convex portion, and the transition portion from the concave portion to the convex portion has a thickness of 0.1 to 0.7 times the plate thickness.
4. The method according to claim 1, wherein the material has a radius of 4.0 times.
7. The deep drawing mold according to 7. 9. A portion having a length of 0.003 to 0.02 times the diameter of the material to be molded, which is located inside the radius start position of the molding die facing the inner holder, is formed in the molding die. In the inner holder corresponding to the part having a length of 0.003 to 0.02,
A 0.6 times step is formed, and the wrinkle suppressing surface of the inner holder and the step transition portion have a radius having 0.5 times or more of the material to be molded and a relief having an angle of 10 to 30 degrees with respect to the wrinkle suppressing surface. The deep drawing mold according to any one of claims 1 to 8, wherein the portion has at least a portion serving as an ear of the cup.