JP2008036658A - Deep drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method by deep drawing by which fine forming by deep drawing is made possible by properly securing the flow property of a material. <P>SOLUTION: This forming method by the deep drawing is composed of a preforming stage and the final forming stage. In the preforming stage, a punch 22 is entered into a recessed part 21a formed on a die 21 together with a metal sheet 10. Because working liquid A is hermetically sealed in the recessed part 21, the working liquid A is pressurized when the metal sheet 10 is entered together with the punch 21. Thus, the metal sheet 10 is tightly pressed against the punch 22 by the increased liquid pressure of the working liquid A and the outer peripheral shape which is formed larger than the finally formed shape is transferred. Further, in the final forming stage, the drawn shape part of the preformed part 10' which is preliminarily formed is reduced and formed so as to become the final shape size. In this way, the flow property of the material is properly ensured and the fine forming by deep drawing is made possible. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a deep drawing method for deep drawing a flat material.

  2. Description of the Related Art Conventionally, for example, a press molding method for rectangular tube parts as shown in Patent Document 1 below is known. In this square tube part press molding method, a notch having a predetermined shape is provided in a blank, and the blank is pressed into a metal plate to suppress cracks and wrinkles and deepen the square tube. It is designed to be drawn. However, in the conventional press forming method of the rectangular tube part, since a desired rectangular tube shape is formed by a single press process, the fluidity of the material may not be sufficiently ensured. For this reason, for example, when deep drawing is performed on the metal plate, there is a high possibility that a crack will occur in the vicinity of the forming corner.

In this regard, for example, in Patent Document 2 below, a metal that is previously formed by hydraulic forming to generate a strain necessary for forming the metal plate, and then finally formed into a desired shape by press working. A thin plate forming method is shown. Further, for example, in Patent Document 3 below, there is a manufacturing method of an automobile door guard bar in which a cross-sectional area and an R shape larger than the product shape are formed by the first drawing process and then reduced to the product shape. It is shown.
JP-A-9-285825 JP-A-5-212464 Japanese Patent Publication No. 7-100184

  By the way, in the metal sheet forming method described above, the liquid sealed on the punch (punch) side of the metal sheet (material) is pressurized to act on the metal sheet to deform the metal sheet. In this case, the metal thin plate is deformed in a state where it is in contact with the liquid on one side and in contact with air on the other side, so that a large frictional force does not act on the metal thin plate. For this reason, when deformed by the action of hydraulic pressure, a uniform material flow may not be ensured due to variations in sheet thickness or mechanical strength of the thin metal sheet. There is a possibility that thinning or cracking may occur.

  Moreover, in the manufacturing method of the door guard bar for motor vehicles mentioned above, a cross-sectional area and a big shape of R shape are shape | molded previously by inserting a punch with a high-strength steel plate (raw material) in a shaping | molding recess. However, in this case, since the punch is formed while stretching the high-tensile steel plate, there is a possibility that the fluidity of the material is locally broken at the contact portion between the punch and the high-tensile steel plate. For this reason, depending on the amount of punch insertion, there is a high possibility that local thinning, cracking, or the like occurs in the high-tensile steel plate during the processing.

  As described above, in the conventional methods shown in Patent Documents 2 and 3, the processing force is applied to the material from one direction, more specifically, only from the punch side of the material. Molding, that is, preforming is performed. For this reason, especially when deep drawing is performed on the material, it is difficult to ensure adequate fluidity of the material, and it is difficult to perform deep drawing by preventing the material from thinning and cracking. is there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a deep-drawing method that can ensure good fluidity and enable good deep-drawing. It is in.

  In order to achieve the above object, the feature of the present invention is greater than the final bulge shape in a deep drawing method for molding a predetermined bulge shape to a predetermined bulge amount with respect to a flat plate material. A flat plate-like material is interposed between the first male mold having the bulging shape and the first female mold having the accommodating section that allows the same male mold to enter, and the first female mold accommodating section is disposed in the first female mold. Filling the liquid in a sealed state, moving the first male mold relative to the first female mold, and pushing the first male mold together with the material into the housing portion to fill the liquid Pressurizing and deforming the material by relative movement of the first male mold, and pressing and deforming the material against the first male mold by the pressurized liquid; Pre-mold a bulge shape that is larger than the final bulge shape, and The preformed material is interposed between a second male mold for molding a shape and a second female mold for molding the final bulge shape, and the second male mold is inserted into the second male mold. It is to move relatively to the female mold No. 2 to reduce the preformed bulge shape and finally form the final bulge shape.

  In this case, in the preforming, the flat plate-like material is applied to the opening peripheral portion of the first female mold housing portion so that air does not enter in the state where the first female mold housing portion is filled with liquid. After the first preforming step to be placed and after the first preforming step, the blank holder located on the outer periphery of the first male mold is moved toward the first female mold and placed as described above A second preforming step of sandwiching a peripheral portion of the flat plate material between the blank holder and an opening peripheral portion of the first female mold accommodating portion; and after the second pre-forming step, the first male mold Is moved relative to the first female mold, the central portion of the flat plate-like material is pressed and deformed by the first male mold, and the liquid is compressed and pressurized, and the pressure is increased. A third preformer for transferring the bulging shape of the first male mold onto the material by liquid Through the door, it is preferable to shape the large bulge shape than that of the final bulged shape with respect to the material.

  In the final molding, the second male mold is inserted into the preformed bulge-shaped portion, and is positioned on the outer periphery of the second male mold and can be displaced in the axial direction of the same male mold. A first step of placing a peripheral portion of the preformed bulge-shaped portion on a pad; and after the first step, the second male die is relatively positioned with respect to the second female die. The final bulge shape may be formed on the preformed material through a second main step of moving and deforming the preformed bulge shape portion while reducing the final bulge shape to the final bulge shape. .

  According to these, the mechanical working force based on the relative displacement of the first male mold is applied from one side of the material and the liquid pressure of the liquid pressurized from the other side of the material is applied, A bulge shape larger than the final bulge shape can be preformed. Thereby, an appropriate frictional force can be generated between the material and the first male mold, and an excessive flow of the material can be prevented. Moreover, since the hydraulic pressure acts uniformly on the entire material that has entered the liquid, the material can be uniformly pressed against the first male mold, and the bulging shape of the first male mold Can be transferred satisfactorily. Therefore, local thinning of the material can be suppressed, and a bulge shape larger than the final bulge shape can be preformed with respect to the material.

  Further, by sandwiching the preformed material between the second male mold and the second female mold, the preformed bulge shape can be reduced to form the final bulge shape. Thereby, the fluidity | liquidity of the material required for shaping | molding can fully be ensured, and an unnecessary tensile force is not made to act with respect to a raw material. Therefore, even when the final bulging shape is formed, local thinning and cracking can be prevented, and satisfactory deep drawing can be performed.

  In addition, the size of the corner portion existing in the first male bulge shape may be larger than the size of the corresponding corner portion of the final bulge shape. Further, it is preferable that the size of the corner between the inner peripheral surface forming the first female housing and the surface forming the peripheral portion of the housing is large. Further, a cross-sectional area in a direction perpendicular to the bulging molding direction of the preformed bulging shape and a cross-sectional area in a direction parallel to the bulging molding direction are perpendicular to the bulging molding direction of the final bulging shape. The cross-sectional area in the direction and the cross-sectional area in the direction parallel to the bulging forming direction may be larger.

  According to these, in the deep drawing, the material can be made to flow appropriately with respect to corner portions that are generally susceptible to thinning and cracking. That is, by forming a corner that is larger than the size of the corner of the final bulge shape by preforming, more specifically, by forming the cross-sectional length of the cross-sectional shape of the preformed portion to be large, It can be molded while reducing the cross-sectional length. And by reducing the cross-sectional length in the final molding in this way, the tensile force that is likely to occur when molding to the final bulging shape is reduced, in other words, the material can be properly flowed, As a result, thinning and cracking at the corners can be effectively prevented.

  Further, the final bulge shape may have a substantially square cross-sectional shape in a direction orthogonal to the bulge forming direction, and the corners of the substantially square shape may be small. Furthermore, it is preferable that the size of the corners in the cross-sectional shape in the direction parallel to the bulge forming direction is small. Thereby, the internal volume of the deep drawing part can be used efficiently, and space saving can be achieved.

  Furthermore, the final bulging shape may be formed after the preliminary molding for a component mounted on a vehicle. According to this, the mechanical strength of the deep-drawn molded product can be effectively prevented by forming the final bulge shape after preforming as described above, thereby effectively preventing local thinning and cracking of the material. And sufficient airtightness can be secured. Therefore, even a vehicle-mounted component that requires sufficient mechanical strength and airtightness can satisfy these requirements satisfactorily.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 to FIG. 3 show a preforming step constituting the deep drawing method of the present invention. And the preforming shape shown in FIG. 5 is shape | molded with respect to the flat metal thin plate 10 by the hydraulic forming machine 20 advancing each process of a preforming process one by one. FIG. 6 and FIG. 7 show the final forming step constituting the deep drawing method of the present invention. And the press molding machine 30 advances each process of a final shaping | molding process sequentially, and shape | molds the final shaping | molding shape shown in FIG. 8 with respect to the metal thin plate 10 preformed. Hereinafter, it demonstrates in detail from a preforming process in order.

  As shown in FIGS. 1 to 3, a hydraulic forming machine 20 that preforms a flat metal thin plate 10 includes a die 21 as a first female die, and a punch 22 as a first male die. A blank holder 23 is provided.

  For example, as shown in FIG. 1, the die 21 is fixed to the base B at the lower end surface, and includes a recessed portion 21 a as an accommodating portion that opens upward at a substantially upper center portion. The hollow portion 21a is formed in a size that allows the punch 22 to be inserted, and a support portion 21b for placing and supporting a thin metal plate is formed at the upper end portion of the hollow portion 21a. In addition, the cross-sectional shape of the hollow portion 21a in the vertical cross section in the figure is formed so that the opening area increases from the opening portion toward the bottom portion (so-called reverse taper shape), and the corner portion 21c on the opening portion side. For example, the size (radius) of the R shape is larger than the size (radius) of the corner of the final shape corresponding to the corner 21c. Furthermore, the depth dimension of the hollow part 21a is formed larger than the depth dimension of the final molded shape.

  The hollow portion 21a is filled with a predetermined working liquid A. For this reason, for example, as shown in FIG. 1, a liquid replenishing device S for replenishing the working liquid A reduced by molding is connected to the die 21 via an on-off valve S1, and is connected to the on-off valve S1. The liquid introduction pipe S2 thus opened is opened at the bottom of the recess 21a. Here, the on-off valve S1 is closed when the hydraulic forming apparatus 20 is in operation, that is, when the throttle shape is preformed on the thin metal plate 10, and shuts off the conduction of the working liquid A.

  In addition, after the preforming and before the punch 22 is lifted and retracted, the punch 22 is opened to release the hydraulic pressure, and when the working liquid A is replenished, the working liquid A is also opened. Allow continuity. Moreover, the working liquid A may become high temperature by continuous drawing of a drawing shape. In this case, the liquid replenishing device S may be provided with a cooling device for cooling the working liquid A so that the cooled working liquid A is replenished to the recess 21a.

  For example, as shown in FIG. 1, the punch 22 is integrally fixed to the lower surface side of the inner slider I configured to be movable up and down in the axial direction at the upper end surface, and the outer peripheral dimension thereof is a depression of the die 21. The dimension is smaller by a predetermined amount than the opening dimension of the portion 21a. The size (radius) of the R shape in the full corner portion 22a that contacts the thin metal plate 10 of the punch 22 is formed larger than the size (radius) of the corner portion of the final molded shape corresponding to the corner portion 22a. ing. Here, the dimension that is smaller by a predetermined amount is a dimension that is determined in consideration of the thickness of the thin metal plate 10 and the thickness variation in manufacturing.

  The blank holder 23 is integrally fixed to the lower surface side of the outer slider O configured to be movable up and down in the axial direction at the upper end surface, and is positioned on the outer periphery of the punch 22. And the lower end surface of the blank holder 23 is arrange | positioned facing the support part 21b of the die | dye 21. As shown in FIG.

  Next, the operation of pre-forming the thin metal sheet 10 from the first pre-forming step shown in FIG. 1 through the third pre-forming step shown in FIG. Details will be sequentially described from the process.

  In the first preforming step shown in FIG. 1, the thin metal plate 10 is placed on the support portion 21 b in a state in which the working liquid A is filled until reaching the upper end portion of the recessed portion 21 a of the die 21. At this time, when the working liquid A is not filled until it reaches the upper end of the recess 21a, the working liquid A is refilled by operating the liquid replenishing device S and opening the on-off valve S1. When the working liquid A is filled until it reaches the upper end of the recess 21a, the liquid replenishing device S is stopped and the on-off valve S1 is closed. When placing the thin metal plate 10 on the support portion 21b, care must be taken so that air does not enter between the liquid surface of the working liquid A and the thin metal plate 10.

  Thus, when the metal thin plate 10 is placed on the support portion 21b, the working liquid A is formed from the lower surface of the metal thin plate 10, the recessed portion 21a, the liquid introduction conduit S2, and the on-off valve S1. The space (hereinafter, this space is referred to as a sealed space) is filled.

  In the second preforming step shown in FIG. 2, the outer slider O is lowered, and the blank holder 23 is lowered in the direction of the support portion 21 b of the die 21. And the peripheral part of the thin metal plate 10 mounted in the support part 21b of the die | dye 21 is pinched by the blank holder 23 and the support part 21b. As described above, when the peripheral edge portion of the thin metal plate 10 is held between the blank holder 23 and the support portion 21b, the working liquid A is sealed in the sealed space.

  In the third preforming step shown in FIG. 3, the inner slider I is lowered, the punch 22 is lowered in the direction of the recess 21 a of the die 21, and the punch 22 is moved into the recess 22 a while pressing and deforming the metal thin plate 10. Insert it. More specifically, when the inner slider I is lowered and the punch 22 is lowered, the punch 22 and the metal thin plate 10 come into contact with each other. When the punch 22 is further lowered from this contact state, the punch 22 starts to enter the recessed portion 21 a of the die 21 while pressing and deforming the thin metal plate 10. The gap between the outer peripheral dimension of the punch 22 and the inner peripheral dimension of the opening of the hollow portion 21 a is set to a dimension larger than the plate thickness of the thin metal plate 10. For this reason, when the die 22 enters the recessed portion 21a, the metal thin plate 10 is not sandwiched between the die 21 and the punch 22 and cut.

  As described above, when the punch 22 starts to enter the recessed portion 21a while pressing and deforming the thin metal plate 10, the working liquid A in the sealed space starts to be compressed. Accordingly, the working liquid A is pressurized in proportion to the amount of the punch 22 entering, and as a result, the hydraulic pressure of the working liquid A increases. In this way, when the hydraulic pressure of the working liquid A increases, the thin metal plate 10 is strongly pressed against the outer peripheral surface of the punch 22.

  That is, as shown in FIG. 4, the hydraulic pressure of the working liquid A acts uniformly on the entire thin metal plate 10 that has been pressed and deformed and has entered the working liquid A. Thereby, the metal thin plate 10 is uniformly pressed against the punch 22, and the outer peripheral shape of the punch 22 is uniformly transferred. Further, when the metal pressure acts uniformly on the entire surface, the metal thin plate 10 is pressed against the punch 22, so that an appropriate friction is generated between the outer peripheral surface of the punch 22 and the surface of the metal thin plate 10 in contact with the outer peripheral surface. Force is generated. Therefore, local material flow hardly occurs, and the reduction of the plate thickness in the processed portion can be suppressed.

  Then, by lowering the inner slider I, the punch 22 is inserted into the recessed portion 21a of the die 21 to be larger than the drawing depth of the final molded shape. In this way, by inserting the punch 22 into the recess 21 a of the die 21, a drawn shape portion that is relatively larger than the final formed shape is preformed with respect to the thin metal plate 10.

  That is, as shown in FIG. 5A, the metal plate 10 has a corner 11 larger than the final shape shown by a broken line (hereinafter, the corner 11 is referred to as a plane R shape 11) and FIG. As shown in b), a corner 12 (hereinafter, this corner 12 is referred to as a die R shape 12) and a corner 13 (hereinafter, this corner 13 is referred to as a punch R shape 13) larger than the final molded shape indicated by a broken line ) And a drawing shape portion having a depth dimension larger than the final shaping shape indicated by a broken line is preformed. In the following description, the preformed thin metal plate 10 is referred to as a preformed product 10 '.

  Thus, when the third pre-forming step is completed, the on-off valve S1 is opened and the hydraulic pressure of the working liquid A is released and lowered, and then the inner slider I rises in the axial direction and the punch 22 rises. To do. Subsequently, the outer slider O rises in the axial direction, and the blank holder 23 rises. Thereby, the preformed product 10 ′ is taken out from the hydraulic molding machine 20. Then, the preformed product 10 ′ is supplied to the final molding step shown in FIGS. 6 and 7 so as to be equal to the final molding dimension.

  As shown in FIGS. 6 and 7, the press molding machine 30 for final molding of the preformed product 10 ′ includes a die 31 as a second female mold, a punch 32 as a second male mold, and a pad. 33.

  The die 31 is integrally fixed to the lower surface side of the slider J configured to be movable up and down in the axial direction at the upper end surface, and includes a hollow portion 31a that opens downward in a substantially central lower portion. The hollow portion 31 a is formed in a size that allows the punch 32 to be inserted, and a holding portion 31 b that holds the preform together with the pad 33 is formed at the peripheral portion thereof. Moreover, the opening shape of the hollow part 31a and the cross-sectional shape in the vertical direction in the drawing are formed in a shape that matches the dimensions of the final molded shape.

  The punch 32 is fixed to the base B at the lower end surface, and the outer peripheral dimension thereof is smaller than the opening dimension of the recess 31 a of the die 31 by a predetermined amount. The size (radius) of the R shape at the corner 32a that contacts the preformed product 10 'of the punch 32 is formed in accordance with the size (radius) of the corner of the final molded shape corresponding to the corner 32a. ing. Here, the dimension that is smaller by a predetermined amount is a dimension that is determined in consideration of the thickness of the metal thin plate and the thickness variation in manufacturing.

  The pad 33 is fixed integrally with the upper end side of the cushion pin C configured to be movable up and down in the axial direction on the lower end surface, and is positioned on the outer periphery of the punch 32. And the upper end surface of the pad 33 is arrange | positioned facing the clamping part 31b of the die | dye 31. FIG. The cushion pin C is operated by using, for example, hydraulic pressure or gas pressure.

  Next, the first operation of the press molding machine 30 configured as described above through the first main process shown in FIG. 6 and the second main process shown in FIG. 7 to the final molded product K shown in FIG. Details will be sequentially described from this step.

  In the first main process shown in FIG. 6, the opening-side peripheral portion of the drawn shape portion is placed on the upper surface of the pad 33 with the punch 32 inserted in the drawn shape portion of the preform 10 ′. In this state, a predetermined gap is generated between the upper end surface of the punch 32 and the inner peripheral surface of the drawn portion of the preformed product 10 '.

  In the second main process shown in FIG. 7, the slider J is lowered, and the die 31 is lowered in the direction of the punch 32 and the pad 33. As a result, the punch 32 enters the recessed portion 31 a of the die 31 together with the drawn shape portion of the preformed product 10 ′. As described above, when the punch 32 and the drawn shape portion of the preformed product 10 ′ enter the hollow portion 31 a of the die 31, the size (radius) of the pre-formed planar R shape 11 is the size of the final molding size. The diameter is reduced to (radius).

  Further, the pad 33 supported by the cushion pin C with respect to the lowering of the die 31 holds the preformed product 10 ′, so that the bottom surface (upper surface) of the recessed portion 31 a of the die 31 is the bottom surface (upper surface) of the drawn portion. Crush. As a result, the size (radius) of the preformed punch R shape 13 is reduced to the size (radius) of the final molding dimension, and the depth dimension of the preformed drawn shape portion is reduced to the depth of the product shape dimension. Shrink to size.

  Further, when the preformed part 10 'is strongly clamped by the pad 33 supported by the cushion pin C by the clamping part 31b of the die 31, the corner part 31c on the opening part side of the die 31 is strongly against the preformed part 10'. Abut. Thereby, the size (radius) of the preformed die R shape 12 is reduced to the size (radius) of the final product dimension.

  Here, in the case where the die 31 is lowered and the preformed planar R shape 11, die R shape 12, punch R shape 13 and depth dimension are reduced to the final molding dimension in the same process, it accompanies the processing. Since the material flow can be appropriately secured, the occurrence of cracks and the like can be effectively prevented. This will be specifically described.

  First, the die 31 descends to reduce the diameter of the preformed planar R shape 11, so that surplus material (so-called surplus) flows preferentially in the direction of the vertical wall surface (side surface) of the drawn shape portion. To do. Then, when the surplus material flows in the direction of the vertical wall surface (side surface), the material forming the vertical wall surface (side surface) easily flows in the direction of the die R shape 12. Thereby, when the preformed die R shape 12 is reduced in diameter, it can be prevented from being excessively stretched, and the die R shape 12 can be favorably reduced in diameter.

  Further, when the die 31 descends and crushes the bottom surface (upper surface) of the drawn shape portion of the preformed product 10 ′, the surplus of the bottom surface (upper surface) flows in the direction of the punch R shape 13. As a result, when the diameter of the preformed punch R shape 13 is reduced, the surplus is supplied satisfactorily, so that the diameter can be reduced extremely easily.

  Thus, when the second main process is completed, the slider J is raised in the axial direction, and the die 31 is raised. As a result, as shown in FIG. 8, a final molded product K having a substantially square-shaped drawn portion having a final molding dimension can be formed on the thin metal plate 10.

  As can be understood from the above description, according to the deep drawing method of the present embodiment, the metal thin plate 10 is preliminarily molded using the hydraulic molding machine 20, and then the press molding machine 30 is used. The final forming step can be performed. Thereby, it is possible to perform a pre-molding in which the cross-sectional shape is larger than the cross-sectional shape of the final forming dimension, that is, the cross-sectional length is large and the thinning amount of the thin metal plate 10 is reduced. Then, by performing final molding in a state in which the fluidity of the material is sufficiently ensured, generation of cracks in the pre-formed flat R shape 11, die R shape 12, and punch R shape 13 is prevented and the depth is improved. Drawing can be performed.

  Moreover, since the fluidity | liquidity of material can fully be ensured, the magnitude | size (radius) of the corner | angular part of a product (part) can be shape | molded small. Furthermore, since the configuration of the press molding machine 30 used in the main molding process can be simplified, the manufacturing cost of the product can be reduced.

  By adopting the above-described deep drawing method of the present invention, a container or the like that requires airtightness, vibration resistance, and compactness can be manufactured extremely well. Hereinafter, an example will be described.

  Examples of containers that require airtightness, vibration resistance, and compactness include a stack case for a fuel cell. As shown in FIG. 9, the fuel cell stack case 40 includes a pair of upper and lower upper case members 41 and a lower case member 42.

  The upper case member 41 is formed by a rectangular drawing formed with a predetermined opening area and a predetermined depth (height) in a substantially central portion of a flat metal thin plate by the deep drawing method according to the present invention described above. A portion 41a and a flange portion 41b formed around the throttle portion 41a are provided. The lower case member 42 is also a corner formed by a deep drawing method according to the present invention described above at a substantially central portion with a predetermined opening area and a depth (height) dimension larger than the drawn portion 41a of the upper case member 41. And a flange portion 42b formed around the throttle portion 42a. Here, the upper case member 41 and the lower case member 42 are formed of a thin metal plate (for example, an aluminum alloy, a stainless steel plate, a steel plate, or the like) having a predetermined plate thickness.

    Then, by connecting the flange portion 41b and the flange portion 42b in a state where the opening side of the throttle portion 41a of the upper case member 41 and the opening side of the throttle portion 42a of the lower case member 42 are opposed to each other, for example, a solid A stack case 40 for the polymer fuel cell is formed. Specifically, for example, the stack case 40 can be formed by accommodating a plurality of single cells stacked in the throttle part 42 a of the lower case member 42 and assembling the upper case member 41.

  As described above, by using the deep drawing method according to the present invention, it is possible to prevent cracks at the corners due to the molding, and thus it is possible to sufficiently ensure airtightness. Thereby, for example, leakage of hydrogen gas introduced into the fuel cell stack to the outside can be prevented.

  Further, by using the deep drawing method according to the present invention, local reduction in thickness (thinning) due to molding can be suppressed. As a result, the mechanical strength of the stack case can be sufficiently ensured.For example, even when the fuel cell stack is mounted on a vehicle and vibrations accompanying traveling are input, the stack case can be damaged. It can be surely prevented.

  Furthermore, the size (radius) of the corner portion of the stack case 40 can be reduced by using the deep drawing method according to the present invention. Thereby, since the internal volumes of the throttle portions 41a and 42a can be used effectively, a compact stack case 40 can be formed. Therefore, space saving can be achieved, and as a result, for example, it is possible to ensure a degree of freedom of mounting when mounted on a vehicle.

  Moreover, as a container which requires airtightness, vibration resistance, and compactness, for example, a fuel tank for a vehicle can be cited. Similarly to the stack case 40 shown in FIG. 9, this vehicle fuel tank is also composed of, for example, an upper case member and a lower case member. The upper case member and the lower case member are also formed by the deep drawing method according to the present invention. Therefore, like the above-described stack case 40, airtightness, vibration resistance, and compactness can be ensured satisfactorily.

  In the description of the above embodiment, it has been described that the final molded product K having a flat peripheral portion (so-called flange portion) on the opening side of the aperture-shaped portion is formed. However, it goes without saying that a final molded product having no flange portion can be molded. In this case, for example, the flange portion may be excised after preliminary molding, or the flange portion may be excised after final molding.

It is the schematic for demonstrating the 1st preforming process which the hydraulic forming apparatus which concerns on one Embodiment of this invention performs. It is the schematic for demonstrating the 2nd preforming process which the hydraulic forming apparatus which concerns on one Embodiment of this invention performs. It is the schematic for demonstrating the 3rd preforming process which the hydraulic forming apparatus which concerns on one Embodiment of this invention performs. It is a figure for demonstrating the effect | action of the liquid pressure of the working liquid A in the 3rd preforming process shown in FIG. (A), (b) shows a preform, (a) is a top view, (b) is sectional drawing. It is the schematic for demonstrating the 1st main process which the press molding apparatus which concerns on one Embodiment of this invention performs. It is the schematic for demonstrating the 2nd main process which the press molding apparatus which concerns on one Embodiment of this invention performs. It is a perspective view which shows the final molded product finally molded. It is the perspective view which showed schematically the stack case for fuel cells shape | molded by the deep drawing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Metal thin plate, 11 ... Plane R shape, 12 ... Die R shape, 13 ... Punch R shape, 20 ... Hydraulic forming apparatus, 21 ... Die, 21a ... Recessed part, 21b ... Support part, 22 ... Punch, 23 ... Blank holder, 30 ... press molding machine, 31 ... die, 32 ... punch, 33 ... pad, I ... inner slider, O ... outer slider, J ... slider, C ... cushion pin

Claims (9)

In the deep drawing method for forming a predetermined bulging shape into a predetermined bulging amount for a flat plate material,
A flat plate-like material is interposed between the first male mold having a larger bulge shape than the final bulge shape and the first female mold having a housing portion that allows entry of the same male mold. Filling the first female housing with liquid in a sealed state;
Relatively moving the first male mold toward the first female mold, and pressurizing the liquid by pushing the first male mold together with the material into the accommodating portion;
The material is deformed by the relative movement of the first male mold and is deformed by pressing the material against the first male mold with the pressurized liquid to deform the final bulge with respect to the material. Pre-form a bulge shape larger than the shape,
The preformed material is interposed between a second male mold for molding the final bulge shape and a second female mold for molding the final bulge shape, and the second male mold A deep drawing method, wherein a mold is moved relative to the second female mold to reduce the preformed bulge shape and finally form the final bulge shape. In the deep drawing method according to claim 1,
The preform is
A first preforming step of placing the plate-shaped material on the peripheral edge of the opening of the first female mold housing portion so that air does not enter in a state where the first female mold housing portion is filled with liquid. When,
After the first preforming step, the blank holder located on the outer periphery of the first male mold is moved toward the first female mold, and the peripheral portion of the flat plate-like material placed above is replaced with the blank. A second pre-molding step sandwiched between the holder and the opening peripheral edge portion of the first female mold accommodating portion;
After the second pre-forming step, the first male mold is moved relative to the first female mold, and the central portion of the flat plate material is pressed and deformed by the first male mold. The final bulge is applied to the material through a third preforming step of compressing and pressurizing the liquid, and transferring the bulging shape of the first male mold to the material by the pressurized liquid. A deep drawing forming method characterized by forming a bulging shape larger than the shape. In the deep drawing method according to claim 1,
The final molding is
The second male mold is inserted into the preformed bulge-shaped portion, and the preform is formed on a pad that is located on the outer periphery of the second male mold and can be displaced in the axial direction of the male mold. A first main step of placing the peripheral portion of the bulging shape portion;
After the first main step, the second male mold is moved relative to the second female mold, and the preformed bulge shape portion is deformed while being reduced to the final bulge shape. A deep drawing forming method, wherein the final bulging shape is formed on the preformed material through a second main step. In the deep drawing method according to claim 1,
The deep drawing method according to claim 1, wherein a size of a corner portion of the first male bulge shape is larger than a size of a corresponding corner portion of the final bulge shape. In the deep drawing method according to claim 1,
A deep drawing method characterized in that the size of the corner between the inner peripheral surface forming the first female mold accommodating portion and the surface forming the peripheral portion of the accommodating portion is large. In the deep drawing method according to claim 1,
The cross-sectional area in the direction orthogonal to the bulging molding direction of the preformed bulging shape and the cross-sectional area in the direction parallel to the bulging molding direction are in the direction orthogonal to the bulging molding direction of the final bulging shape. A deep drawing method characterized by being larger than a cross-sectional area and a cross-sectional area in a direction parallel to the bulging forming direction. In the deep drawing method according to claim 1,
The final bulging shape is a deep drawing method characterized in that a cross-sectional shape in a direction orthogonal to the bulging molding direction is substantially square, and a corner portion of the substantially square shape is small. In the deep drawing method according to claim 7,
Furthermore, the deep drawing method characterized in that the size of the corners in the cross-sectional shape in the direction parallel to the bulge forming direction is small. In the deep drawing method according to any one of claims 1 to 8,
A deep drawing forming method, wherein the final bulging shape is formed after the preforming for a component mounted on a vehicle.

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