JP2001071042A - Forming die for multiple rugged plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming die capable of forming many rugged parts having a large depth or height based on a plate thickness without developing the crack of a stock. SOLUTION: A die has at least a pair of clamp members 8, 9 to press/clamp a plate stock 1 in the thickness direction, many die holes 12, 13 formed for the clamp members 8, 9 and many punch parts 14, 15, which are arranged opposite to the die holes for the plate stock 1 pressed/clamped by the clamp members 8, 9 and are inserted into the die holes 12, 13. A shape of the tip part of the punch parts 14, 15 and a shape of the inner face of the die holes 12, 13 are set so that a reduction ratio of the min gap between the punch parts 14, 15 and the die holes 12, 13 is <=30%, while the plate stock 1 is projectingly deformed at least three times of the thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered unevenness in which a relatively large number of unevenness portions are provided by forming a plurality of concave portions or convex portions on at least one surface while forming a plate shape as a whole. The present invention relates to a mold for molding a plate.

[0002]

2. Description of the Related Art For example, a solid electrolyte type fuel cell constitutes a single cell (single cell) by providing electrodes on both sides of a flat electrolyte, and a fuel cell stack is formed by stacking a large number of such single cells. Then, power is taken out at the required voltage and current. In that case, electricity is taken out by conducting to each electrode, and a fuel gas (for example, hydrogen gas) or an oxidizing gas (for example, air) is applied to the surface of the electrolyte through each electrode.
In order to supply a reaction gas such as the above, a separator is arranged on the surface side of the electrode, that is, between each single cell.

[0003] Therefore, the separator is made of a conductive material for extracting electric power, and is configured to be in conductive contact with the electrode and to form a flow path for flowing a reaction gas between the separator and the surface of the electrode. It is necessary to have. In order to satisfy such demands, multiple irregularities are formed on a conductive plate material such as a metal by forming a large number of irregularities, contacting the convexities with the electrodes, and communicating the concaves with each other to form a gas flow path. May be used as a separator.

[0004] When the multiple uneven plate is used as a separator for a fuel cell, in order to increase current collection efficiency and power generation efficiency of the fuel cell, the tip surface (top surface) of the convex portion is formed in a flat surface to form an electrode. In order to increase the contact area as much as possible and to promote the flow of the reaction gas, it is desired that the height of the projection is about 1.5 times or more the plate thickness. Further, it is desirable to reduce the pitch of the projections as much as possible to increase the overall contact area with the electrodes.

Conventionally, an apparatus for continuously forming an uneven portion on a metal strip such as a strip or a wire has been disclosed in Japanese Patent Laid-Open Publication No. Hei.
No. 0-263714. In the apparatus described in this publication, a male mold and a female mold are set in a press machine, and a metal strip is intermittently fed between these molding dies. It is configured to intermittently process and form the uneven portion on the strip.

[0006]

The above-mentioned publication describes a technique for intermittently feeding a metal strip to continuously form an uneven portion. As described above, there is no description of what kind of processing such as processing involving elongation of the material or simple bending. If the apparatus described in this publication is an apparatus that forms an uneven portion by bending, the pitch and height of the obtained uneven portion are greatly limited, and as described above, the height of the convex portion is set to the height of the material plate. It is almost impossible to make the thickness 1.5 times or more of the plate thickness or to make the pitch of the projections a value as small as its outer diameter. In addition, even if the above-described apparatus is an apparatus that performs overhanging processing, if it is a conventionally known simple overhanging processing, when the pitch of the convexities or concaves is made as small as possible, each of the convexes or concaves can be formed. Material tension between
This is likely to cause cracks, especially when the height of the projections is 1.5 times or more the thickness of the material plate, and furthermore, the pitch of the projections is set to a value as small as its outer diameter. In this case, cracks almost certainly occur.

In the apparatus described in the above publication,
If an error occurs in the pitch of the intermittent feed of the metal strip, this will cause an error in the interval between the concave and convex portions, and in order to prevent such inconvenience, the metal strip is formed on the basis of the already formed concave portion or convex portion. If the position of the material is determined, it is necessary to perform an operation of fitting a concave portion or a convex portion to a portion serving as a reference for positioning, and there is an inconvenience that an operation that is difficult and has low productivity is required. Furthermore, if the feed speed is increased, the acceleration associated with intermittent feed may increase, causing an error in the feed pitch. Therefore, the feed speed is limited, and it is difficult to increase the productivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problem, and is intended to prevent a large number of uneven portions having a small gap and a large depth or height with respect to a diameter from causing cracks or cracks in a material. It is an object of the present invention to provide a molding die that can be molded efficiently without any problems.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a method for forming a large number of concave / convex portions by expanding a plate-shaped material. The change in the minimum gap between the two is limited to a predetermined value or less to prevent the material from being excessively compressed or pulled, thereby preventing the material from being cracked or cracked. That is, the invention of claim 1 is a molding die for a multiple uneven plate, which forms a large number of uneven portions by pressing and deforming a plurality of portions of a plastic plate material in the thickness direction thereof, At least a pair of sandwiching members that are sandwiched by pressing in the plate thickness direction, a number of die holes formed in the sandwiching member, and the die holes with respect to the plate-shaped material that is sandwiched by being pressed by the sandwiching member. Are disposed on the opposite side and have a number of punch portions fitted into the die holes, and the shape of the tip of the punch portions and the shape of the inner surface of the die holes are adjusted by the punch portions to form the plate. A molding die characterized in that a reduction ratio of a minimum gap between a punch portion and a die hole is reduced to 30% or less during a convex deformation of the shaped material to at least three times its plate thickness.

A second aspect of the present invention is a molding die according to the first aspect, wherein the punch portion and the die hole are both formed in a tapered shape.

[0011] By moving the punch portion in the direction of the die hole, the minimum gap between the outer surface of the punch portion and the inner surface of the die hole gradually decreases.
Since the reduction rate of the minimum gap is configured to be 30% or less when a part of the plate-like material is convexly deformed up to three times its thickness, the plate-like material is formed into a punch portion and a die hole. As a result, the material is not excessively compressed or excessively constrained, and as a result, the elongation of the material in the entire portion to be deformed is promoted, and the depth of the concave portion or the height of the convex portion is reduced. The height can be increased, and cracking and cracking of the material can be prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be specifically described with reference to the drawings. FIG. 1 is a diagram showing the principle of the configuration of a molding die according to the present invention. A workpiece 1 to be processed is a conductive plate-like material such as a metal plate.
The upper die 2 and the lower die 3 are arranged with a pass line for feeding the nip therebetween. These upper mold 2 and lower mold 3 are provided with intermediate plates 4 and 5, respectively, which receive cushion pressure.
The pressure plates 6, 7 and the dies 8, 9 are held by the intermediate plates 4, 5, respectively.

The pressure plates 6 and 7 are plate members having relatively high rigidity and are directed in a direction perpendicular to the stroke direction of the upper and lower dies 2 and 3, that is, in a direction parallel to the workpiece 1. It is held by intermediate plates 4 and 5. Dies 8 and 9 are fixed to the surfaces of the pressure plates 6 and 7 facing the workpiece 1. Each of the dies 8, 9 is a highly rigid block-shaped member, and is provided with a punch hole 1 at predetermined intervals.
0, 11 and die holes 12, 13 are formed. The die hole 13 in the lower die 3 faces the punch hole 10 in the upper die 2, and the punch hole 11 in the lower die 3 faces the die hole 12 in the upper die 2.

The punch holes 10, 11 penetrate the dies 8, 9 and the pressure plates 6, 7 in the stroke direction (vertical direction) of the dies 2, 3, and the punches 14, 11 are formed therein.
15 is inserted to be able to move up and down. In addition, each punch 1
The rear ends of the pressure plates 4 and 15 protrude from the rear surfaces of the pressure plates 6 and 7, and the front ends thereof are connected to the rams 16 and 17.
That is, there is a predetermined space between the pressure plates 6, 7 and the rams 16, 17, and the ram 16,
17 and punches 14 and 15 make a stroke.

Further, the die holes 12 and 13 are formed in the workpiece 1.
The receiving pins 18, 19 for defining the processing limit positions of the punches 14, 15 are arranged inside the opening. That is, the respective standby pins 18 and 19 are attached to the pressure plates 6 and 7 such that the positions of the distal ends thereof are set back from the open ends of the die holes 12 and 13 by a predetermined dimension.

Therefore, for example, when the upper die 2 descends and the upper and lower dies 2 and 3 relatively approach each other, the workpiece 1 is pressed and held by the upper and lower dies 8 and 9,
In this state, the punches 14 and 15 are pushed by the rams 16 and 17 and move forward to the workpiece 1, whereby the punches 14 and 15 are moved.
A part 15 presses and deforms a part of the workpiece 1 into the die holes 12 and 13 to form a concave part or a convex part. Therefore, the above dies 8, 9 correspond to the holding member of the present invention. Punch 14,1 in the process of the processing
The leading end of the die 5 enters the inside of the die holes 12 and 13, and the punches are adjusted so that the change rate of the minimum gap between the punches 14 and 15 and the die holes 12 and 13 at this time is as follows. The shapes of 14, 14 and the die holes 12, 13 are set.

FIG. 2 schematically shows the shapes of the tips of the punches 14 and 15 and the shapes of the open ends of the die holes 12 and 13. The shapes of the tips of the punches 14 and 15 correspond to the punch angle (taper angle). Of the die holes 12 and 13 are formed in a tapered shape in accordance with the shape. In addition, each punch 14,
The radii (corner radii) of the 15 tip corners are set to predetermined values. The punch angle and the corner radius are, in short, the distance between the punches 14 and 15 and the die holes 12 and 13 when the punches 14 and 15 are stroked at least three times the thickness of the workpiece 1. Is set to a value such that the change rate of the minimum gap is 30% or less. An example is as follows.

Four punches having the following shapes were prepared at the tip end, and an overhanging process (coining process) was performed on the concave and convex shapes using the mold shown in FIG. 1, and the processed shapes were evaluated. Shape 1: The punch angle at the tip is 18 degrees 10 minutes (36 degrees 20 minutes at the taper angle), and the radius of the tip corner is 1.0 m
m. Shape 2: The punch angle at the tip is 11 degrees 12 minutes (22 degrees 24 minutes in the taper angle), and the radius of the tip corner is 2.5 m
m. Shape 3: The punch angle at the tip is 11 degrees 12 minutes (22 degrees 24 minutes at the taper angle), and the radius of the tip corner is 1.0 m
m. Shape 4: spherical shape having the same outer diameter as the outer diameter of the straight shaft portion.

Each of the punches 14 and 15 is stroked by a predetermined size, and the punches 14 and 15 and the
The change in the minimum gap (minimum clearance) between Sample Nos. 2 and 13 was measured, and the occurrence of cracks in the molded product was observed. The measurement result is shown in FIG. The thickness of the workpiece was 0.3 mm. The plate holding force was set to 50% or more of the yield stress of the workpiece. Further, the outer diameter of each of the punches 14, 15 was 1.0 mm.

FIG. 3 shows the result of measuring the change in the minimum clearance between the punch and the die when each punch is moved by 1 mm from the state in which the punch is in contact with the workpiece. , The change rate of the minimum clearance was about 30%, and the molded article did not crack. On the other hand, when a punch of shape 2 is used,
The reduction rate of the minimum clearance was almost 50%, and the molded product was cracked. When the punch having the above-mentioned shape 3 was used, the reduction rate of the minimum clearance was almost 40%, and cracks occurred in the molded product. Further, when the punch having the above-mentioned shape 4 was used, the reduction rate of the minimum clearance was almost 50%, and the molded product was cracked.

After all, when the uneven shape is formed by coining up to 3.3 times the sheet thickness, the amount of change in the sheet thickness at the processing portion, that is, the ratio of the change in the minimum gap between the punch and the die hole, is about If the punch and die holes have a shape of 30% or less, a concave (or convex) forming process by coining can be performed without causing cracks. Therefore, in the present invention, the reduction rate of the minimum gap between the punch and the die hole when the plate material is deformed at least three times the thickness thereof is reduced by 30%.
It was as follows.

Here, the relationship between the tip shape of the punch and the shape of the die hole and the relative limit overhang height (H / t) in the overhanging process is shown. FIG. 4 shows the results of measuring the ratio of the plate thickness t to the overhanging height H in the overhanging process for a plurality of types of punches and die holes at each molding temperature. This is an example in which a punch having an angle and a corner radius of a tip portion of 2.5 mm and a die having a tapered hole are used. The line B is an example in which a punch having a punch angle of 18 degrees and 10 minutes and a corner radius of a tip portion of 2.5 mm and a die having a straight hole are used. The line C is an example using a spherical punch having a radius of 10 mm and a die having a straight hole. Line D is an example in which a spherical punch having a radius of 10 mm and a die having a tapered hole are used.

As is clear from the results shown in FIG.
By setting the tip of the punch to a tapered shape and appropriately setting the radius of the rounding (rounding) at the corner, the overhang limit height can be made higher than that of the spherical punch. In particular, by adopting a shape in which the reduction ratio of the minimum gap between the punch and the die becomes small, it becomes possible to increase the processing size without causing cracks.

Although the above-described specific example is an example used for a vertical-stroke type press machine, the molding die of the present invention can be configured to continuously form the concave and convex portions. . An example will be described below. The apparatus provided with the forming die shown in FIG. 5 performs a coining process (extending process) involving elongation or flow of a material on a conductive plate-like material such as a metal plate to form a large number of convex portions (or concave portions).
This is a device for forming the material, and is particularly configured to continuously perform the forming process. That is, in FIG. 5, a pair of large-diameter rollers 21 and 22 are arranged close enough to contact their outer peripheral portions, and the distance between the outer peripheral surfaces of these rollers 21 and 22 at the closest position is set as follows. Is set to be equal to or less than the thickness of the workpiece 1 such as a metal plate.

The upper roller 21 in FIG. 5 has a hollow structure, and its outer shell (peripheral wall) 24 has a large number of through holes 25 formed at a constant pitch. Further, on the outer peripheral surface of the lower roller 22 in FIG. 5, a large number of concave portions 26 are formed at the same pitch as the through holes 25 so as to face the openings of the through holes 25. The pair of rollers 21 and 22
Are set so that the phases in the rotational direction are aligned so that the respective through holes 25 and the concave portions 26 face each other in a one-to-one correspondence, and rotate synchronously. The rotational driving force may be applied to the respective rollers 21 and 22. However, as described later, these rollers 21 and 22 may be used.
2 rotates substantially in mesh with each other, so that the rotational driving force may be transmitted to only one of the rollers 21 and 22.

The pair of rollers 21 and 22 press the work 1 in the thickness direction thereof to constrain the work 1 and rotate the work 1 in one direction so that the work 1 travels in one direction. It is. Therefore, in order to increase the constraint area (restriction range) of the workpiece 1 as much as possible, the workpiece 1
The outer diameter is set to be much larger than the plate thickness. Further, in order to increase the contact area by elastic deformation, a large load is set in a direction in which the rollers 21 and 22 are brought closer to each other. FIG. 6 is an enlarged view of the state in which the workpiece 1 is held between the rollers 21 and 22 in this manner.

A forming roller 27 is disposed inside the upper roller 21 in FIG. 5 in which the above-mentioned through hole 25 is formed. The forming roller 27 is used to continuously perform a convex or concave coining process on the workpiece 1, and a tip portion of the forming roller 27 enters the concave portion 26 through the through hole 25. A large number of punch portions 28 are provided on the outer peripheral portion. Then, the punch portion 28 is disposed at a position eccentric to the lower side in FIG. 5 with respect to the upper roller 21 so that the punch portion 28 projects between the upper and lower rollers 21 and 22.

The shape of the punch portion 28 and the concave portion 26 corresponding to the die hole is such that the punch portion 28 is at least three times the plate thickness of the workpiece 1 as in the above-described specific example. The shape is such that the rate of decrease in the minimum gap between the two when entering the space 26 is 30% or less. Specifically, the shape can be obtained by creating a model and simulating it, or by performing an experiment.

Therefore, the pitch of the tip of the punch portion 28 is set to be the same as the pitch of the through hole 25 and the concave portion 26. In addition, the length of the workpiece 1 protrudes toward the recess 26 through the through-hole 25, and a deformation of a predetermined depth (for example, about 1.5 times the thickness of the workpiece 1) is formed on the workpiece 1. Set to length.

Further, the forming roller 27 is adjusted so that the forming process by the punch portion 28 of the forming roller 27 is not a simple bending process but a coining process (or an overhanging process) that causes the material to extend or flow.
And a predetermined dimension δ offset from the front side in the rotational direction. That is, the punch portion 28
Is performed while the punch portion 28 advances rightward in FIG. 5 with the rotation of the forming roller 27, so that the material of the workpiece 1 has a pulling force in the rightward direction in FIG. Works. On the other hand, a pair of upper and lower rollers 2
The clamping of the workpiece 1 by the workpieces 1 and 22 is the strongest on a line connecting the centers thereof.

Therefore, the position where the punch portion 28 performs the deepest processing on the workpiece 1, that is, the forming roller 27
The position immediately below the center of FIG.
The offset amount δ is set so as to be on the front side (front side in the rotation direction) of the strongest holding portion by the first and second 22. As a result, the elongation or flow of the material occurs only at the processing portion by the punch portion 28. Then, it is processed into a predetermined uneven shape. This is to prevent cracks due to the joining of the materials between the processing portions adjacent to each other, and to increase the processing depth.

The operation of the molding die according to the present invention mainly comprising the three rollers 21, 22, 27 will be described below. The rollers 21, 22, and 27 are rotated so that their peripheral speeds are the same. In this state, the workpiece 1 is fed between the pair of upper and lower rollers 21 and 22 from the rear side (the left side in FIG. 5) in the rotation direction. As described above, the interval between the pair of upper and lower rollers 21 and 22 is set to be equal to or less than the thickness of the workpiece 1 and is configured to approach the workpiece 1 so as to sandwich the workpiece 1. Workpiece 1 sent between rollers 21 and 22
Is transported forward (to the right in FIG. 5) with the rotation of the rollers 21 and 22. Therefore, the pair of upper and lower rollers 21 and 22 correspond to the holding member in the present invention.

The forming roller 27 is arranged on the inner peripheral side of the upper roller 21 in FIG. 5 and is a roller having a smaller diameter than this roller 21. The roller 21 gradually enters the through-hole 25 of the roller 21, projects from the through-hole 25 toward the lower roller 22, and then gradually retreats into the through-hole 25. As described above, the punch portion 28 gradually acts on the workpiece 1 that is held and restrained by the upper and lower rollers 21 and 22 and is running in the rotation direction, and coining accompanied by the extension or flow of the material. Process (or overhang). FIG. 7 is an enlarged view of this state, in which the rollers 21, 22, and 27 are in mesh with each other via the through hole 25, the punch portion 28, and the concave portion 26.

Particularly, in the apparatus having the above-described structure, since the forming roller 27 is arranged offset with respect to the pair of upper and lower rollers 21 and 22 in the rotational direction thereof,
The material is stretched or flown at the processing part due to the above, and the material does not come into contact between adjacent processing parts. As a result, it is possible to apply a concave processing with a large depth (or height) to the workpiece 1 without cracking.

Therefore, even in the configuration shown in FIG. 5, the workpiece 1 is restrained by pressing in the thickness direction, and coining is performed at a position adjacent to the restrained portion. The processing of the concave shape (or the convex shape) is performed by the extension or the flow. And
Since the shape of the punch portion 28 and the concave portion 26 corresponding to the die hole are the above-described shapes, the thickness of the sheet is reduced as much as possible by the elongation or flow of the material, thereby causing cracks. And the processing height can be increased.

[0036]

As described above, according to the molding die of the present invention, when the punch portion is inserted toward the die hole with the plate-like material interposed therebetween, the minimum gap between the punch portion and the die hole is reduced. The punch portions and the die holes are configured so that the ratio is 30% or less when a portion of the plate-shaped material is convexly deformed up to three times the plate thickness, so that a large number of uneven portions are formed. In this case, excessive compression of the plate-shaped material and accompanying strong restraint do not occur, and as a result, the elongation of the material in the entire portion to be deformed is promoted, and the depth of the concave portion or the height of the convex portion is increased. And cracks and cracks in the material can be prevented.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of a molding die according to the present invention.

FIG. 2 is a partially enlarged view schematically showing a tip shape of the punch portion and a shape of an opening of a die hole.

FIG. 3 is a diagram showing a measurement result of a minimum gap for each punch of each shape.

FIG. 4 is a diagram showing a measurement result of a relative overhang height for each shape of a punch and a die.

FIG. 5 is a diagram schematically showing an example of a molding die according to the present invention configured to perform continuous molding.

FIG. 6 is a partial view of a state in which a workpiece is held between upper and lower rollers.

FIG. 7 is a partial view showing a processing state of a workpiece. 1
... work material, 2 ... upper die, 3 ... lower die, 8,9 ... die, 12,13 ... die hole, 14,15 ... punch,
Reference numerals 21, 22, rollers, 26, concave portions, 27, forming rollers, 28, punch portions.

Claims (2)

[Claims] 1. A forming die for a multiple uneven plate, wherein a plurality of uneven portions are formed by pressing a plurality of portions of a plastic plate material in a thickness direction thereof to deform the plate material. At least a pair of sandwiching members, which are sandwiched by pressing, a plurality of dice holes formed in the sandwiching member, and the opposite side of the die holes with respect to the plate-shaped material which is sandwiched by being pressed by the sandwiching member. And a number of punch portions fitted into the die hole, and the shape of the tip portion of the punch portion and the shape of the inner surface of the die hole, the plate-shaped material by the punch portion A mold having a shape in which a reduction rate of a minimum gap between a punch portion and a die hole during a convex deformation of at least three times the plate thickness is 30% or less. . 2. The mold according to claim 1, wherein both the punch portion and the die hole are formed in a tapered shape.