Manufacturing method of metallic component

Abstract

To provide a manufacturing method of a metallic component which can suppress processing failure such as creases and warp and which is excellent in productivity.SOLUTION: A manufacturing method of a metallic component transcribes a groove shape extending in a lengthwise direction of a belt-like metal plate where an uneven shape viewed in a cross section continues in a width direction of the metal plate into the metal plate through a plurality of molding rolls for molding. The manufacturing method of the metallic component comprises the steps of: transcribing a temporary groove shape where an uneven shape is rough by a temporary molding roll into a central part of the metal plate in the width direction (temporary roll molding process); and continuously transcribing the groove shape through a main molding roll into the metal plate into which the temporary groove is transcribed (main roll molding process) to mold the metallic component. Rotation speed of the main molding roll is higher than that of the temporary molding roll, or timing of starting rotation of the main molding roll is earlier than that of the temporary molding roll.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a metal processing method, and more particularly to a method for manufacturing a metal member having a continuous concave-convex shape by roll forming. [Background technology]

[0002] Patent Document 1 describes a multistage roll forming apparatus for forming fuel cell separators in which a concave-convex shape is formed around a flat metal material. The multistage roll forming apparatus described in Patent Document 1 is composed of a reference roll on which a concave-convex shape perpendicular to the roll axis direction is formed in the circumferential direction of the roll peripheral surface, and multiple forming rolls arranged circumferentially contacting the reference roll and on which a concave-convex shape perpendicular to the roll axis direction is formed in the circumferential direction of the roll peripheral surface. Of the multiple forming rolls, at least one of the groove depth or the width of the convex portion of the concave-convex shape of the n-th forming roll (n=2 or 3) from the start of forming is formed so as to be larger than the concave-convex shape of the n-1th forming roll.

[0003] Furthermore, Patent Document 2 describes a metal separator for fuel cells and a manufacturing method thereof that aims to provide a highly accurate fuel cell separator by enabling the processing of complex concave-convex shapes. In the manufacturing method for a metal separator for fuel cells described in Patent Document 2, for example, a stainless steel plate or a clad material of an aluminum alloy and a titanium alloy is used as a material, and a metal separator for fuel cells having a trapezoidal concave-convex cross section is formed by press processing.

[0004] Patent Document 3 describes a method for manufacturing a grooved metal plate, which aims to form a metal plate in which the thickness of the grooves is less likely to become thin. In the method for manufacturing a grooved metal plate described in Patent Document 3, multiple roll forming dies, each having a pair of convex and concave rolls, are arranged in the flow direction of a flat metal plate. A metal plate is passed between the pair of convex and concave rolls, and grooves that are continuous in the flow direction are formed in the metal plate in stages using the multiple roll forming dies. The clearance between the pair of convex and concave rolls is set to decrease toward the downstream side in the flow direction of the metal plate. The spacing between adjacent convex portions and the spacing between adjacent concave portions are each set to decrease toward the downstream side in the flow direction of the metal plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-289447 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-76304 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-147306 Summary of the Invention [Problem to be solved by the invention]

[0006] The multi-stage roll-forming apparatus described in Patent Document 1 rolls metal separators for fuel cells. Fuel cells are manufactured by stacking multiple metal separators made of materials such as stainless steel plates, aluminum alloys, or titanium. Therefore, efficient mass production of high-quality metal separators is crucial for widespread adoption of fuel cells. Furthermore, as described in Patent Document 2, metal separators for fuel cells require highly accurate formation of inclined flow passages for properly discharging water generated during power generation and flat portions for tight contact with the electrolyte membrane. To achieve this, the manufacturing method for metal separators for fuel cells described in Patent Document 2 involves press-forming the flat portions to a uniformly thin thickness of 90% or less of the base of the metal separator, and then forming the inclined portions, thereby achieving the concave-convex shape with highly accurate inclined and flat portions.

[0007] On the other hand, the roll forming described in Patent Documents 1 and 3 allows for continuous processing of metal members with the same cross-sectional shape at high precision and high speed. Therefore, by manufacturing a large number of metal separators for fuel cells by roll forming, improved productivity can be expected compared to manufacturing by conventional press working. On the other hand, when manufacturing metal separators with the above-mentioned uneven shape by roll forming, if the uneven shape of the metal separator is processed by roll forming while the continuous (long) material is warped or sagging, there is a high risk of excess or deficiency of material being fed into the forming roll, which can easily result in processing defects such as "wrinkles" and "warping."

[0008] This invention was devised with a focus on the above-mentioned technical problems, and aims to provide a method for manufacturing metal components that suppresses the occurrence of processing defects such as "wrinkles" and "warping" and has excellent productivity. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a method for manufacturing a metal member in which a cross section of a convexo-concave shape that is continuous in the width direction of a strip-shaped or rectangular metal plate has a groove shape extending in the length direction of the metal plate, the cross section being formed by transferring the groove shape to the metal plate using a plurality of forming rolls, the forming rolls including at least a temporary forming roll that transfers a temporary groove shape in which the depth or height of the convexo-concave shape is greater than the groove shape and the pitch of the convexo-concave shape is coarse, and a main forming roll that transfers the groove shape, and the temporary forming rolls are positioned at a central portion in the width direction of the metal plate. The method is characterized in that the provisional groove shape is transferred using a roll, and the groove shape is continuously transferred using the final forming roll to the metal plate to which the provisional groove shape has been transferred, thereby forming the metal member, and when the provisional forming roll and the final forming roll continuously transfer the provisional groove shape and the groove shape to the metal plate, respectively, the provisional forming roll and the final forming roll are each rotated so that the angular velocity of the final forming roll is faster than that of the provisional forming roll, or so that the start timing of the final forming roll is earlier than that of the provisional forming roll, thereby applying tension to the metal plate.

[0010] The provisional forming roll in this invention may have at least a rough forming roll that first transfers the provisional groove shape to the metal plate, and an intermediate forming roll that transfers the provisional groove shape between the rough forming roll and the final forming roll. The rough forming roll in this invention may transfer, as the provisional groove shape, a rough groove shape in which the depth or height of the concave-convex shape is the largest and the pitch of the concave-convex shape is the coarseest, or a single concave or convex shape. The intermediate forming roll in this invention may transfer, as the provisional groove shape, an intermediate groove shape in which the depth or height of the concave-convex shape is smaller than that of the rough groove shape and the pitch of the concave-convex shape is finer, and in which the depth or height of the concave-convex shape is larger than that of the groove shape and the pitch of the concave-convex shape is coarser. The manufacturing method of this invention includes forming the provisional groove shape in the central part in the width direction of the metal plate. The rough groove shape is transferred by a forming roll, the intermediate groove shape is continuously transferred to the metal plate to which the rough groove shape has been transferred by the intermediate forming roll, and the groove shape is continuously transferred by the final forming roll to the metal plate to which the intermediate groove shape has been transferred, thereby forming the metal member, and when the rough forming roll, the intermediate forming roll, and the final forming roll continuously transfer the rough groove shape, the intermediate groove shape, and the groove shape to the metal plate, respectively, the rough forming roll, the intermediate forming roll, and the final forming roll may each be rotated so that the angular velocity of the intermediate forming roll is faster than that of the rough forming roll, or so that the start timing of the intermediate forming roll is earlier than that of the rough forming roll and so that the angular velocity of the final forming roll is faster than that of the intermediate forming roll, or so that the start timing of the final forming roll is earlier than that of the intermediate forming roll.

[0011] Furthermore, the groove shape in this invention may have an upper bottom portion that forms the outer end of the convex side of the uneven shape, a lower bottom portion that forms the inner bottom of the concave side of the uneven shape, and an inclined portion that connects the upper bottom portion and the lower bottom portion, and the forming roll in this invention may form the outer surface of the upper bottom portion into a flat surface having a predetermined flatness, and form the outer surface of the inclined portion into an inclined surface having a predetermined flatness.

[0012] The metal member in this invention may be a metal separator for a fuel cell, the flat surface in this invention may be a smooth surface that is in close contact with the electrolyte membrane of the fuel cell, and the inclined surface in this invention may be a smooth surface that allows water generated when the fuel cell generates electricity to flow down and be discharged. [Effects of the Invention]

[0013] The metal member of this invention is a rectangular, plate-like member made of metal, formed from a strip-shaped or elongated metal plate or a rectangular metal plate. The metal member of this invention also has a groove shape formed in its cross section, with concave and convex shapes alternating continuously across the width. The groove shape is formed by transferring the above-described concave and convex shapes using multiple forming rolls. That is, the groove shape in the metal member of this invention is formed by so-called roll forming or roll forming. When forming a groove shape with continuous concave and convex shapes, processing defects such as "wrinkles" and "warping" are likely to occur when the material is rolled and transferred due to the influence of plastic flow and residual stress of the metal material. Therefore, in the method for manufacturing a metal member of this invention, when the above-described groove shape is formed by roll forming, the roll forming process is divided into multiple steps: a step of transferring a provisional groove shape using a provisional forming roll, and a step of transferring a final groove shape using a formal forming roll, and the groove shape is formed by these steps. In roll forming using a temporary forming roll, a temporary groove shape is first formed in the center of the metal plate in the width direction, with a rougher uneven shape (the concave grooves are deeper or the convex shapes are taller) than the groove shape to be finally formed. Next, in roll forming using a final forming roll, the metal plate to which the temporary groove shape has been transferred is formed with a groove shape that will become the product shape. The size and shape of the forming roll mold (the number and size of the uneven shapes) can be appropriately set to take into account the fluidity of the metal material during plastic deformation, so that excess or deficiency of material flowing when transferring the groove shape can be avoided, thereby suppressing the occurrence of processing defects.

[0014] Furthermore, the process of transferring the provisional groove shape using the provisional forming roll may be divided into two processes: a process of transferring a rough groove shape using a rough forming roll, and a process of transferring an intermediate groove shape using an intermediate forming roll. Alternatively, it may be divided into three or more processes. In roll forming using a rough forming roll, a rough groove shape with the coarsest uneven shape is first formed in the central portion in the width direction of the metal plate. A single concave or convex groove may be formed as the rough groove shape. Subsequently, in roll forming using an intermediate forming roll, an intermediate groove shape, which is an uneven shape intermediate between the final groove shape and the rough groove shape, is formed in the metal plate to which the rough groove shape has been transferred. Then, a groove shape is formed in the metal plate to which the intermediate groove shape has been transferred using a final forming roll. In short, in the method for manufacturing a metal member of this invention, when a groove shape is transferred to a strip-shaped or rectangular metal plate by roll forming, uneven grooves are formed sequentially from the central portion in the width direction of the material (metal plate) toward both outer end portions. In addition, in the thickness direction of the material (metal plate), the deepest recesses or the highest protrusions are formed first, followed by successively shallower or shorter uneven grooves, until the groove shape that will become the product shape is formed. By performing roll forming in such multiple steps, the size and shape (number and size of uneven shapes) of the forming roll dies used in each step can be precisely set, taking into account the fluidity of the metal material in plastic deformation, and therefore the occurrence of processing defects due to the plastic flow of the metal material when roll forming the groove shape can be appropriately suppressed.

[0015] Furthermore, in the method for manufacturing a metal member of the present invention, when the groove shape described above is formed by roll forming in multiple steps, the rotation of the forming rolls in each step is adjusted to prevent sagging or drooping of the material (metal plate) fed into the forming rolls. For example, the rotations of the provisional forming roll and the final forming roll are adjusted so that the provisional forming roll rotates faster than the provisional forming roll, or so that the final forming roll starts rotating earlier than the provisional forming roll. Also, the rotations of the rough forming roll, intermediate forming roll, and final forming roll are adjusted so that the intermediate forming roll rotates faster than the rough forming roll and the final forming roll rotates faster than the intermediate forming roll, or so that the intermediate forming roll starts rotating earlier than the rough forming roll and the final forming roll starts rotating earlier than the intermediate forming roll. In this way, when the groove shape is formed continuously in multiple steps, the rotation of each forming roll is adjusted so that the forming roll in the later step rotates faster or starts rotating earlier. This allows the material (metal plate) fed into the forming rolls to be given an appropriate tension, preventing the material from sagging or drooping, and thus effectively suppressing the occurrence of processing defects caused by variations in, excess or deficiency of the metal material fed when forming the groove shape into the roll.

[0016] Therefore, according to the method for manufacturing a metal member of the present invention, when a groove shape with a cross section having a continuous concave-convex shape is formed in a strip-shaped or rectangular metal plate by roll forming, the occurrence of processing defects such as "wrinkles" and "warping" can be suppressed, thereby improving the productivity of metal members having such groove shapes. For example, this can improve the productivity of metal separators for fuel cells, which require high-precision forming of a flat surface that comes into close contact with the electrolyte membrane to prevent transmission loss of generated electricity, and an inclined surface that allows water generated during power generation to flow down and be properly discharged. [Brief explanation of the drawings]

[0017] [Figure 1]FIG. 1 is a perspective view for explaining the configuration (image) of a metal member to be manufactured by the method for manufacturing a metal member of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of a metal member to be manufactured by the method of manufacturing a metal member of the present invention, and is a cross-sectional view showing an enlarged portion of a metal separator for a fuel cell. [Figure 3] FIG. 3 is a cross-sectional view illustrating a forming roll used when roll-forming the groove shape (flow path) of a metal member (metal separator) in the method for producing a metal member of the present invention. [Figure 4] FIG. 4 is a process diagram (flowchart) for explaining the forming process when the groove shape (flow passage) of the metal member (metal separator) is formed by roll forming in the manufacturing method of the metal member of the present invention. [Figure 5] FIG. 5 is a diagram illustrating a plurality of forming rolls (rough forming roll, intermediate forming roll, and main forming roll) used when roll-forming the groove shape (flow path) of a metal member (metal separator) in the manufacturing method of a metal member of the present invention. [Figure 6] FIG. 6 is a diagram for explaining the multiple forming steps (rough roll forming step, intermediate roll forming step, and main roll forming step) when roll-forming the groove shape (flow path) of a metal member (metal separator) in the metal member manufacturing method of the present invention, as well as the groove shapes (rough groove shape, intermediate groove shape, and final groove shape) formed in these multiple forming steps. [Figure 7] FIG. 7 is a diagram for explaining the state (image) of the plastic flow of the metal material when the groove shape (flow path) of the metal member (metal separator) is roll-formed in the manufacturing method of the metal member of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0019] The "metal member" to be manufactured in the embodiment of this invention is a rectangular, plate-shaped member made of metal, having a "groove shape" with a continuous concave-convex shape, and is formed from a strip-shaped or long "metal plate" or a rectangular "metal plate." In the manufacturing method of the metal member in the embodiment of this invention, the "groove shape" in the "metal member" is rolled using a plurality of "forming rolls." In other words, the "groove shape" is transferred and formed on the "metal plate" material by so-called roll forming. First, FIG. 1 shows an example of the "metal member" to be manufactured in the embodiment of this invention.

[0020] The metal member 1 shown in FIG. 1 is a rectangular plate-like member formed from a predetermined metal. The metal member 1 has a cross section of a concave-convex shape 4, in which concave portions 2 and convex portions 3 are alternately arranged in a width direction WD, with a groove shape 5 extending in a length direction LD. The material of the metal member 1 may be any metal that can be rolled and plastically processed. For example, the metal member 1 can be formed from stainless steel, aluminum alloy, titanium alloy or pure titanium, copper alloy or pure copper, or the like.

[0021] FIG. 2 shows a portion of a fuel cell 10 as an example in which the manufacturing method of a metal member that is the subject of an embodiment of the present invention is applied to a "metal separator for a fuel cell." That is, the metal member 1 shown in FIG. 2 is a metal separator 11 that constitutes the fuel cell 10, and is formed from a material such as stainless steel or titanium. FIG. 2 also shows a portion of a cross section of a flow path 15 of the metal separator 11. The flow path 15 has a configuration similar to the groove shape 5 shown in FIG. 1 above. That is, the flow path 15 has a "groove shape" in which a cross section of an uneven shape 14 in which recesses 12 and protrusions 13 are alternately arranged in a width direction of the metal separator 11 (left and right direction in FIG. 2) extends in the length direction of the metal separator 11 (front and back direction on the paper in FIG. 2).

[0022] The flow path 15 of the metal separator 11 is formed by an upper base 16, a lower base 17, and an inclined portion 18. The upper base 16 forms the outer end 13a of the convex portion 13 in the uneven shape 14 of the cross section of the flow path 15. The lower base 17 forms the inner bottom 12a of the concave portion 12 in the uneven shape 14 of the cross section of the flow path 15. The inclined portion 18 connects the upper base 16 and the lower base 17 to form an inclined surface 18a, which will be described later.

[0023] The outer surface of the upper bottom portion 16, i.e., the upper surface of the outer end 13a in Figure 2, is a flat surface 16a with a predetermined flatness, which serves as a "smooth surface" for the metal separator 11 to come into close contact with the electrolyte membrane 19 of the fuel cell 10.

[0024] The outer surface of the inclined portion 18, i.e., the inner surface of the recess 12 connected to the inner bottom 12a, is a smooth inclined surface 18a with a predetermined flatness, which serves as a "smooth surface" for allowing water generated when the fuel cell 10 generates electricity to flow down and be discharged.

[0025] As described above, in the fuel cell 10, the flow channels 15 of the metal separator 11 must be formed with high precision and quality to ensure appropriate intimate contact between the flat surface 16a of the flow channels 15 of the metal separator 11 and the electrolyte membrane 19, and to allow water to flow down the inclined surface 18a of the flow channels 15 of the metal separator 11 appropriately. Furthermore, because the fuel cell 10 is constructed by stacking a large number of metal separators 11, the metal separators 11 must be mass-produced with high precision. Therefore, in the method for manufacturing a metal member according to an embodiment of the present invention, the metal separator 11 having the flow channels 15 described above, i.e., the metal member 1 having the groove shape 5, is manufactured by so-called roll forming. In particular, in the method for manufacturing a metal member according to an embodiment of the present invention, when manufacturing such a metal member 1 (metal separator 11), the groove shape 5 (flow channels 15) is transferred and formed on a metal plate using multiple "forming rolls."

[0026] Specifically, in the method for manufacturing a metal part according to an embodiment of the present invention, a plurality of "forming rolls" including at least a "main forming roll" and a "pre-forming roll" are used to form the groove shape 5 (flow path 15) in a plurality of roll forming steps.

[0027] The "forming roll" is configured, for example, as in the forming roll 20 shown in FIG. 3, by a pair of a concave roll 21 and a convex roll 22. In the example shown in FIG. 3, the concave roll 21 is formed with a concave mold 21a that serves as the prototype of the "recesses" of the "uneven shape" or "groove shape" to be formed. The convex roll 22 is formed with a convex mold 22a that fits in correspondence with the concave mold 21a in the concave roll 21. A strip-shaped metal plate (not shown) that serves as the material is passed between the concave roll 21 and the convex roll 22 and rolled to plastically deform the metal material, thereby transferring a shape that follows the concave mold 21a and the convex mold 22a to the "metal plate."

[0028] Of the above-mentioned "forming rolls," the "main forming roll" transfers the groove shape 5 (flow path 15) that will be the product shape of the metal member 1 (metal separator 11) or the final formed shape to the "metal plate" material. In other words, the "main forming roll" is a "forming roll" that finally transfers and forms the groove shape 5 (flow path 15) onto the "metal plate" material.

[0029] On the other hand, the "temporary forming roll" is a "forming roll" that transfers a "temporary groove shape" to the "metal plate" of the material. The "temporary groove shape" is a "groove shape (flow path)" in which the depth or height of the uneven shape 4 (uneven shape 14) is greater than that of the groove shape 5 (flow path 15) formed by the above-mentioned "main forming roll" and the pitch of the uneven shape 4 (uneven shape 14) is coarser.

[0030] As will be described later, the "pre-forming roll" may be divided into at least two sets of "forming rolls", namely, a "rough forming roll" and an "intermediate forming roll". Furthermore, the "intermediate forming roll" may be divided into multiple "forming rolls". That is, in the method for manufacturing a metal member according to an embodiment of the present invention, three sets of "forming rolls", namely, a "rough forming roll", an "intermediate forming roll", and a "main forming roll", may be used to form the groove shape 5 (flow path 15) by dividing the roll forming process into three steps. Furthermore, four or more sets of "forming rolls" may be used to form the groove shape 5 (flow path 15) by dividing the roll forming process into four or more steps.

[0031] In the manufacturing method of a metal member in an embodiment of the present invention, when the groove shape 5 (flow path 15) of the metal member 1 (metal separator 11) is formed through multiple roll forming processes, in the first (initial) roll forming process (preliminary forming process), a ``preliminary groove shape'' is transferred to the central part of the ``metal plate'' of the material in the width direction WD by a ``preliminary forming roll.''

[0032] Subsequently, in the final roll forming step (main forming step), the groove shape 5 (flow path 15), i.e., the "final groove shape," is transferred by a "main forming roll" to the "metal plate" to which the above-mentioned "temporary groove shape" has been transferred. Then, the strip-shaped "metal plate" to which the groove shape 5 (flow path 15) has been transferred is cut into a rectangle corresponding to the product shape, thereby forming a metal member 1 (metal separator 11) having a groove shape 5 (flow path 15) with an uneven cross section. Note that the metal member 1 (metal separator 11) having the groove shape 5 (flow path 15) may be formed by processing a "metal plate" previously cut into a rectangle corresponding to the product shape through multiple roll forming steps as described above.

[0033] As described above, in the manufacturing method of a metal member according to an embodiment of the present invention, the groove shape 5 (flow path 15) of the metal member 1 (metal separator 11) is formed in multiple roll forming processes, which allows the size and shape of the "temporary forming roll" mold or the number and size of the "concave and convex shapes" of the "temporary groove shape" to be appropriately set in consideration of the fluidity of the metal material in plastic deformation. Therefore, it is possible to avoid an excess or deficiency of the metal material that is plastically flowed when transferring the groove shape 5 (flow path 15) that will become the final product shape, thereby suppressing the occurrence of processing defects.

[0034] Furthermore, in the manufacturing method of a metal member according to an embodiment of the present invention, when the groove shape 5 (flow path 15) of the metal member 1 (metal separator 11) is formed through multiple roll forming processes as described above, the "temporary forming roll" and the "main forming roll" are rotated so that the angular velocity of the subsequent "temporary forming roll" is faster than that of the previous "temporary forming roll," or so that the angular velocity of the final "main forming roll" is faster than that of the previous "temporary forming roll." Alternatively, the "temporary forming roll" and the "main forming roll" are rotated so that the start timing of the subsequent "temporary forming roll" is earlier than that of the previous "temporary forming roll," or so that the start timing of the final "main forming roll" is earlier than that of the previous "temporary forming roll." This applies an appropriate tension to the "metal plate" of material fed into each "forming roll," preventing the material from sagging or drooping. This makes it possible to prevent variations in, excess or deficiency of the metal material added when processing the groove shape 5 (flow path 15) by roll forming, and thus to appropriately suppress the occurrence of processing defects caused by such variations in, excess or deficiency of the metal material.

[0035] As a more specific example, Figures 4 and 5 show the steps for manufacturing a metal separator 11 (metal member 1) using the metal member manufacturing method according to an embodiment of the present invention, and an image of a "forming roll." Figure 4 is particularly a process diagram (or flowchart) for processing the flow paths 15 (groove shape 5) of the metal separator 11 (metal member 1) by roll forming. Figure 5 shows an image of multiple "forming rolls" used when processing the flow paths 15 (groove shape 5) of the metal separator 11 (metal member 1) by roll forming.

[0036] As described above, in the method for manufacturing a metal member according to an embodiment of the present invention, the flow paths 15 (groove shapes 5) of the metal separator 11 (metal member 1) are roll-formed using multiple "forming rolls" in multiple forming steps. In the examples shown in Figs. 4 and 5 below and in the examples thereafter, an example will be described in which roll forming is performed using three sets of "forming rolls" in three forming steps.

[0037] In the roll-forming process of the flow channels 15 (groove shape 5) of the metal separator 11 (metal member 1) shown in the process diagram of Fig. 4, first, in the first step P1 (rough roll-forming step), a "rough groove shape" is first transferred to the "metal plate" material by a "rough forming roll" acting as a "temporary forming roll." Therefore, this first step P1 is a "rough roll-forming step" in which the "rough groove shape" is formed using the "rough forming roll," or in other words, a "first roll-forming step" in which the "metal plate" material is subjected to the first roll-forming.

[0038] In the example of roll forming of flow channels 15 (groove shape 5) shown in the process diagram of FIG. 4, as shown in FIG. 5, three sets of forming rolls 100, namely, a rough forming roll (R1) 101, an intermediate forming roll (R2) 102, and a final forming roll (R3) 103, are used to transfer flow channels 15 (groove shape 5) having the shape shown in FIGS. 1 and 2 onto a strip-shaped or rectangular metal plate (material) 104. The rough forming roll 101 and the intermediate forming roll 102 are forming rolls 100 corresponding to the "provisional forming roll" in the embodiment of this invention. The final forming roll 103 is a forming roll 100 that forms flow channels 15 (groove shape 5) that will be the final product shape, i.e., the "final groove shape," and can also be called a "finishing forming roll" or a "final forming roll."

[0039] Note that the reference numerals "105" and "106" in FIG. 5 above both denote "feed rolls" that do not perform rolling. The feed roll 105, located on the input side (left side in FIG. 5) of the metal sheet 104 as a raw material, supports the metal sheet 104 before it is input to the rough forming roll 101, preventing the metal sheet 104 from warping or sagging before being formed. The feed roll 105 rotates in response to the transport of the metal sheet 104 in the processing direction (rightward in FIG. 5). In addition, in order to apply a predetermined tension to the metal sheet 104 before it is input to the rough forming roll 101, the feed roll 105 may be provided with a predetermined rotational resistance or may apply a predetermined pressing force. The magnitude of the predetermined tension applied to the metal sheet 104 is adjusted appropriately within a range that prevents the metal sheet 104 from warping or sagging and does not break the metal sheet due to the tension.

[0040] Meanwhile, the feed roll 106, which is disposed on the discharge side (right side in FIG. 5 ) of the metal separator 11 (metal member 1) that will become the molded product or final product, supports the formed metal plate 104 discharged from the main forming roll 103, i.e., the metal separator 11 (metal member 1) on which the "final groove shape" has been formed. The feed roll 106 is driven to rotate by a power source (not shown), such as a motor, and transports the metal plate 104 before forming and the formed metal separator 11 (metal member 1). In other words, the feed roll 106 serves as a "drive roller" that transports the metal plate 104 and the metal separator 11 (metal member 1). Note that the main forming roll 103, which finally forms the flow passage 15 (groove shape 5), may also function as a "drive roller" together with the feed roll 106. As will be described later, in the method for manufacturing a metal part according to an embodiment of the present invention, the rotation speed (angular velocity) of each forming roll 100 and the timing of starting rotation are adjusted by controlling the rotation of the feed roll 106, or the "drive roller" of the feed roll 106 and the main forming roll 103.

[0041] The rough shaping roll 101 used in this first step P1 is a shaping roll 100 that transfers, as a "temporary groove shape," a "coarse groove shape" having the largest depth or height of the uneven shape 4 (uneven shape 14) as shown in FIGS. 1 and 2 and the coarsest pitch of the uneven shape 4 (uneven shape 14), or a cross section of a single "concave shape" or "convex shape." In the example shown in FIG. 6, the rough shaping roll 101 transfers a rough groove shape 201 having a height H1 and a cross section of a single "convex shape." Then, in this first step P1, the rough shaping roll 101 transfers the rough groove shape 201 to the center portion in the width direction WD (left-right direction in FIG. 6) of the metal plate 104.

[0042] In the second step P2 (intermediate roll forming step), an "intermediate groove shape" is continuously transferred by the intermediate forming roll 102 to the metal plate 104 to which the rough groove shape 201 was transferred in the first step P1. The intermediate forming roll 102 transfers, as a "temporary groove shape," an intermediate groove shape 202 having a smaller depth or height of the uneven shape 4 (uneven shape 14) as shown in FIGS. 1 and 2 and a finer pitch of the uneven shape 4 (uneven shape 14) than the rough groove shape 201, and having a cross section in which the depth or height of the uneven shape 4 (uneven shape 14) is greater than that of the flow path 15 (groove shape 5) and the pitch of the uneven shape 4 (uneven shape 14) is coarser (larger). In the example shown in FIG. 6, the intermediate forming roll 102 transfers an intermediate groove shape 202 having a height H2 (H2

[0043] In the third step P3 (main roll forming step), the flow channels 15 (groove shape 5) are continuously transferred by the main forming roll 103 onto the metal plate 104 to which the intermediate groove shape 202 was transferred in the second step P2. Thereafter, the strip-shaped metal plate 104 to which the groove shape 5 (flow channels 15) was transferred is cut into a rectangle corresponding to the product shape, thereby forming a metal separator 11 (metal member 1) having flow channels 15 (groove shape 5) with an uneven cross section. Note that the metal plate 104 previously cut into a rectangle corresponding to the product shape may be processed through multiple roll forming steps using the above-mentioned forming rolls 100 to form the metal member 1 (metal separator 11) having flow channels 15 (groove shape 5).

[0044] ​The main forming roll 103 used in this third process P3 transfers the groove shape 5, i.e., the flow path 15, which will be the final product shape or formed shape. In the example shown in FIG. 6, the main forming roll 103 has a height H3 (H3 <H2

[0045] As described above, in the manufacturing method of a metal member according to an embodiment of the present invention, when the flow path 15 (groove shape 5) is transferred to a strip-shaped or rectangular metal plate 104 by roll forming, as shown in FIG. 6 , first, a coarse groove shape 201 having a height H1, which is the highest height of the cross-sectional “convex shape,” is formed. Next, an intermediate groove shape 202 having a “convex shape” height H2 is formed, and finally, the flow path 15 (groove shape 5) having a “convex shape” height H3 is formed. Therefore, in the manufacturing method of a metal member according to an embodiment of the present invention, by performing roll forming in three steps as described above, “grooves” having a cross-sectional uneven shape 14 (uneven shape 4) are formed sequentially from the center of the material (metal plate 104) in the width direction WD toward both outer ends. As shown in FIG. 7 , when the coarse groove shape 201 having a height H1 and the intermediate groove shape 202 having a height H2 are roll-formed, the metal material of the metal plate 104 plastically flows overall from the center of the material (metal plate 104) in the width direction WD toward both outer ends. Similarly, when the flow passage 15 (groove shape 5) of height H3 is roll-formed from the state in which the intermediate groove shape 202 has been formed, the metal material plastically flows toward both outer end portions. As a result, the flow passage 15 (groove shape 5) having a uniform or desired thickness and consisting of the flat surface 16a and the inclined surface 18a with the desired flatness is formed with high precision.

[0046] ​As described above, in the manufacturing method of a metal member according to an embodiment of the present invention, roll forming is performed in multiple steps, such as the forming steps P1, P2, and P3. This allows for detailed design of the size and shape (number and size of the uneven shapes 4) of the forming rolls 100 used in the forming steps P1, P2, and P3, taking into account the fluidity of the material (metal sheet 104) during plastic deformation. This allows for precise formation of flow channels 15 (groove shapes 5) with desired shapes and dimensions and flat surfaces 16a and inclined surfaces 18a with desired flatness. Furthermore, when roll-forming such flow channels 15 (groove shapes 5), the occurrence of processing defects due to the plastic flow of the metal material can be appropriately suppressed.

[0047] Furthermore, in the method for manufacturing a metal member according to an embodiment of the present invention, the rotation of each forming roll 100 is adjusted when the rough groove shape 201, the intermediate groove shape 202, and the "final groove shape," i.e., the flow path 15 (groove shape 5), are continuously transferred to the metal sheet 104 in the first step P1, the second step P2, and the third step P3, respectively. Specifically, the rotation of each of the rough forming roll 101, the intermediate forming roll 102, and the final forming roll 103 is adjusted so that the angular velocity of the intermediate forming roll 102 is faster than that of the rough forming roll 101, or so that the start timing of the intermediate forming roll 102 is earlier than that of the rough forming roll 101 and so that the angular velocity of the final forming roll 103 is faster than that of the intermediate forming roll 102. Alternatively, the rotation of each of the rough forming roll 101, the intermediate forming roll 102, and the final forming roll 103 is adjusted so that the start timing of the final forming roll 103 is earlier than that of the intermediate forming roll 102.

[0048] For example, as shown in FIG. 5, if the angular velocity of the feed roll 105 on the input side is ω0, the angular velocity of the rough forming roll 101 is ω1, the angular velocity of the intermediate forming roll 102 is ω2, the angular velocity of the main forming roll 103 is ω3, and the angular velocity of the feed roll 106 on the carry-out side is ω4, then: ω0<ω1<ω2<ω3<ω4 The rotation of each forming roll 100 is adjusted so that

[0049] The rotation of each forming roll 100 as described above can be adjusted, for example, by controlling the rotation of a motor (not shown) that drives the feed roll 106 on the discharge side shown in FIG. 5 , thereby adjusting the rotation speed (angular velocity) of each forming roll 100 and the timing at which it starts to rotate. Alternatively, the main forming roll 103, together with the feed roll 106, may be provided with a "drive roller" function, and the rotation of the motors that drive the feed roll 106 and the main forming roll 103 may be controlled to adjust the rotation speed (angular velocity) of each forming roll 100 and the timing at which it starts to rotate. Alternatively, for example, a brake (not shown) that brakes the rotation of the feed roll 105 on the input side shown in FIG. 5 , or brakes (not shown) that brake the rotation of the feed roll 105 and the rough forming roll 101 may be provided, and the rotation speed (angular velocity) of each forming roll 100 and the timing at which it starts to rotate may be controlled by controlling the operation of the brake. Furthermore, by providing such a "brake" function, it is possible to apply a desired tension to the material (metal plate 104) before it is fed into the rough forming roll 101 or the intermediate forming roll 102.

[0050] In short, in the manufacturing method of a metal member according to an embodiment of the present invention, when the flow paths 15 (groove shape 5) of the metal separator 11 (metal member 1) are formed by roll forming, the process is divided into three steps P1, P2, and P3 as shown in the process diagram of Fig. 4 above, and the rotations of the rough forming roll 101, intermediate forming roll 102, and final forming roll 103 are adjusted so that the intermediate forming roll 102 rotates faster than the rough forming roll 101, and the final forming roll 103 rotates faster than the intermediate forming roll 102. Alternatively, the rotations of the rough forming roll 101, intermediate forming roll 102, and final forming roll 103 are adjusted so that the intermediate forming roll 102 starts to rotate faster than the rough forming roll 101, and the final forming roll 103 starts to rotate faster than the intermediate forming roll 102. Therefore, an appropriate tension is applied to the metal plate 104 material fed into the forming roll 100, and it is possible to prevent the material (metal plate 104) from sagging or drooping before forming. This makes it possible to prevent variations or excesses or deficiencies in the material (metal plate 104) fed when processing the flow path 15 (groove shape 5) by roll forming. It is also possible to appropriately suppress the occurrence of processing defects caused by variations or excesses or deficiencies in the material (metal plate 104).

[0051] As described above, in the manufacturing method of a metal member according to an embodiment of the present invention, when the groove shape 5 (flow path 15) described above is processed by roll forming, the roll forming process is divided into a plurality of steps: a step of transferring a temporary groove shape (rough groove shape 201, intermediate groove shape 202) using temporary forming rolls (rough forming roll 101, intermediate forming roll 102), and a step of transferring a "final groove shape," i.e., groove shape 5 (flow path 15), using a final forming roll 103, to process the groove shape 5 (flow path 15). In the roll forming using the temporary forming rolls (rough forming roll 101, intermediate forming roll 102), first, temporary groove shapes (rough groove shape 201, intermediate groove shape 202) in which the uneven shape 4 (uneven shape 14) is coarser than the "final groove shape" are formed in the central portion of the metal plate 104 in the width direction WD. Subsequently, in roll forming using the main forming roll 103, the metal plate 104 to which the temporary groove shapes (rough groove shape 201, intermediate groove shape 202) have been transferred is formed with the groove shape 5 (flow path 15) that will become the product shape. In this way, when forming the groove shape 5 (flow path 15), the size and shape (the number and size of the uneven shapes 4, 14) of the molds of each forming roll 100 can be appropriately set in consideration of the fluidity of the metal material in plastic deformation, so that excess or deficiency of the material to be flowed when transferring the groove shape 5 (flow path 15) can be avoided, and the occurrence of processing defects can be suppressed.

[0052] Furthermore, in the manufacturing method of a metal member according to an embodiment of the present invention, when the groove shape 5 (flow path 15) as described above is formed by roll forming in a plurality of steps, the rotation of each forming roll 100 is adjusted so that the forming roll 100 in the later step rotates faster or starts rotating earlier. This applies an appropriate tension to the material (metal sheet 104) fed into the forming roll 100, preventing the material (metal sheet 104) from sagging or drooping. This makes it possible to appropriately suppress the occurrence of processing defects due to variations, excesses, or deficiencies in the metal material fed when the groove shape 5 (flow path 15) is roll formed.

[0053] Therefore, according to the manufacturing method of a metal member in an embodiment of the present invention, when a groove shape 5 (flow path 15) having a cross section with a continuous uneven shape 4 (uneven shape 14) is formed on a strip-shaped or rectangular metal plate 104 by roll forming, the occurrence of processing defects such as "wrinkles" and "warping" can be suppressed, thereby improving the productivity of the metal member 1 (metal separator 11) having the above-mentioned groove shape 5 (flow path 15). For example, it can improve the productivity of the metal separator 11 used in a fuel cell 10, which requires high-precision forming of a flat surface 16a that is in close contact with the electrolyte membrane to prevent transmission loss of generated electricity, and an inclined surface 18a that allows water generated during power generation to flow down and be properly discharged. [Explanation of symbols]

[0054] 1 Metallic parts 2 recesses 3 Convex part 4 Uneven shape 5 Groove shape 10 fuel cell 11 Metal separator (metal component) 12 recess 12a (recessed) inner bottom 13 Convex part 13a (outer end of convex part) 14 Uneven shape 15 Flow path (groove shape) 16 Upper base 16a (Upper bottom) flat surface 17 Lower base 18 Slope 18a (Sloped part) inclined surface 19 Electrolyte membrane (for fuel cells) 20 Forming roll 21 (forming roll) concave roll 21a (concave roll) concave 22 (forming roll) convex roll 22a (convex roll) convex 100 forming roll 101 Rough forming roll (R1) (pre-forming roll) 102 Intermediate forming roll (R2) (pre-forming roll) 103 Main forming roll (R3) 104 Metal plate (material) 105 Feed roll 106 Feed roll 201 Rough groove shape (temporary groove shape) 202 Intermediate groove shape (temporary groove shape) LD (Longitudinal direction of metal parts) WD (width direction of metal parts)

Claims

1. A method for producing a metal member in which a cross section of a continuous uneven shape in the width direction of a belt-shaped or rectangular metal plate has a groove shape extending in the length direction of the metal plate, the method comprising: transferring the groove shape to the metal plate using a plurality of forming rolls; The forming roll includes at least a temporary forming roll that transfers a temporary groove shape in which the depth or height of the concave-convex shape is greater than that of the groove shape and the pitch of the concave-convex shape is coarse, and a main forming roll that transfers the groove shape, The provisional groove shape is transferred to a central portion in the width direction of the metal plate by the provisional forming roll; The groove shape is continuously transferred by the main forming roll to the metal plate to which the temporary groove shape has been transferred, thereby forming the metal member; and When the provisional forming roll and the final forming roll continuously transfer the provisional groove shape and the groove shape to the metal plate, respectively, the provisional forming roll and the final forming roll are rotated so that the angular velocity of the final forming roll is faster than that of the provisional forming roll, or so that the start timing of the final forming roll is earlier than that of the provisional forming roll. A method for manufacturing a metal member comprising the steps of:

2. The method for manufacturing a metal member according to claim 1, the provisional forming roll includes at least a rough forming roll that first transfers the provisional groove shape to the metal plate, and an intermediate forming roll that transfers the provisional groove shape between the rough forming roll and the main forming roll, the rough forming roll transfers, as the temporary groove shape, a rough groove shape in which the depth or height of the concave-convex shape is the largest and the pitch of the concave-convex shape is the coarseest, or a rough groove shape in which one concave shape or one convex shape is transferred, the intermediate forming roll transfers, as the temporary groove shape, an intermediate groove shape in which the depth or height of the concave-convex shape is smaller and the pitch of the concave-convex shape is finer than that of the coarse groove shape, and the depth or height of the concave-convex shape is larger and the pitch of the concave-convex shape is coarser than that of the groove shape, The rough groove shape is transferred to a central portion in the width direction of the metal plate by the rough forming roll; The intermediate groove shape is continuously transferred to the metal plate to which the coarse groove shape has been transferred by the intermediate forming roll, The groove shape is continuously transferred by the main forming roll to the metal plate to which the intermediate groove shape has been transferred, thereby forming the metal member; and When the rough forming roll, the intermediate forming roll, and the final forming roll continuously transfer the rough groove shape, the intermediate groove shape, and the groove shape to the metal plate, respectively, the rough forming roll, the intermediate forming roll, and the final forming roll are rotated so that the angular velocity of the intermediate forming roll is faster than that of the rough forming roll, or so that the start timing of the intermediate forming roll is earlier than that of the rough forming roll, and so that the angular velocity of the final forming roll is faster than that of the intermediate forming roll, or so that the start timing of the final forming roll is earlier than that of the intermediate forming roll. A method for manufacturing a metal member comprising the steps of:

3. The method for manufacturing a metal member according to claim 1 or 2, the groove shape has an upper bottom portion forming an outer end of the convex side of the concave-convex shape, a lower bottom portion forming an inner bottom of the concave-convex shape, and an inclined portion connecting the upper bottom portion and the lower bottom portion, The main forming roll forms the outer surface of the upper bottom portion into a flat surface having a predetermined flatness, and forms the outer surface of the inclined portion into an inclined surface having a predetermined flatness. A method for manufacturing a metal member comprising the steps of:

4. The method for manufacturing a metal member according to claim 3, the metal member is a metal separator for a fuel cell, the flat surface is a smooth surface that comes into close contact with an electrolyte membrane of the fuel cell, The inclined surface is a smooth surface that allows water generated when the fuel cell generates electricity to flow down. A method for manufacturing a metal member comprising the steps of:

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