JP2004188473A - Press working method excellent in shape freezing property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To a press working method excellent in shape freezing property by which the structure of a working tool is simplified and parts having highly accurate hat-shaped cross section is obtained. <P>SOLUTION: Drawing is performed while applying bending and unbending to both end parts in the width direction of the metallic sheet 4 by a first shoulder part 5 of a die and, in the process of the drawing or after the completion of the drawing, the forming of the wall part of the metallic sheet is started by the second shoulder part 6 of the die. Next, the die edge part of the metallic sheet is formed by the second shoulder part of the die and also the metallic sheet is clamped with beads provided on the opposite surface 9 of the flange of a punch 1 and the opposite surface 8 of the flange of a die 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press working method excellent in shape freezing property for forming a metal plate into a cross-sectional hat shape.
[0002]
[Prior art]
In recent years, in order to reduce the weight of an automobile body, a high-tensile steel plate having a thinner plate thickness than a conventional material or an aluminum alloy plate having a lower specific gravity has been used as a material. These materials are formed into various parts by press working, but because of their properties that are higher in strength or lower in Young's modulus (longitudinal elastic modulus) than conventional materials, they are inferior in shape freezing properties and target It may be difficult to obtain the shape.
[0003]
For example, when the cross-sectional hat-shaped part 11 as shown in FIG. 8 (a) is obtained by press working, as shown in FIG. 8 (b), the machining tool should have a target two-dot chain line shape. When the molded product is taken out from the shape, the shape shown by the solid line may be exhibited. This is a shape freezing defect in press working. It is known that the shape freezing failure of the part 11 is caused by a springback at a corner portion connecting the hat head 12 and the wall portion 13 and warping at the wall portion 13. In FIG. 8A, reference numeral 14 denotes a flange portion, and reference numeral 15 denotes a die edge portion.
[0004]
As shown in FIGS. 9A and 9B, the cross-sectional hat-shaped component 11 uses a punch 101, a die 102, and a processing tool including a wrinkle presser 103, and a die shoulder portion along the outer shape of the punch 101. In general, the metal plate 104 is bent at 105. Then, there is no problem if the shape of the pressed metal plate 104 is frozen as it is, but in reality, it is formed into a cross-sectional hat shape due to the bending moment generated by the bending and unbending by the die shoulder 105. When the metal plate 104 is removed from the processing tool, the metal plate 104 is elastically deformed so that the bending moment becomes zero. The bending moment generated by bending and unbending by the die shoulder 105 is the cause of defective shape freezing. The higher the strength of the material, the larger the bending moment and the smaller the Young's modulus of the elastic deformation caused by the bending moment. Since the amount of elastic deformation increases as the material plate thickness increases and the material plate thickness decreases, it is important to reduce the bending moment to improve the shape freezing property.
[0005]
By the way, the spring back at the corner portion is made sufficiently small by providing a concave portion having a predetermined depth on at least a part of the convex side of the metal plate 1 subjected to the bending process in the final step of the forming stroke in the press working. It is known that this can be done (Patent Document 1).
Alternatively, when the spring back at the corner is not so large, it is almost solved by putting a prospect in a processing tool such as a punch for obtaining a cross-sectional hat shape in advance so that a predetermined cross-sectional hat shape is obtained after the spring back. It is also known that it can be done.
[0006]
On the other hand, there is a problem that it is difficult to eliminate the warpage of the wall.
For example, when a punch for obtaining a predetermined hat cross-sectional shape is used, a wrinkle holding force is applied to both end portions in the width direction of the metal plate, and when the metal plate is subjected to drawing bending processing, the metal plate is in a state where tension is applied. Then, it is bent by the shoulder portion of the die, bent back, and once formed into a target shape. However, due to the bending moment generated in the metal plate after the press working, when the metal plate after the press working is removed from the processing tool, a large warp may occur in the wall portion so as to open the mouth. This warpage of the wall becomes particularly large when a metal plate material with high strength or a metal plate material with a low Young's modulus is used, so it is difficult to solve by preliminarily bending the bending tool. there were.
[0007]
As a method for suppressing such warpage of the wall portion, a press working method using a movable die is known (Patent Document 2).
In the press working method described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2000-271661), a movable die 205 is provided on the inner wall of a die 202 as shown in FIGS. Retract upward and start forming with punch 201 with the die face of the crimped flange forming part and the die side wrinkle holding part wrinkled, and then move the movable die 205 downward in the figure to make the die shoulder 206, a die edge portion is formed. However, a wrinkle pressing force is applied to both end portions of the metal plate 204 while the wall portion and didge portion of the metal plate 204 are being formed.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-174074 [Patent Document 2]
Japanese Patent Laid-Open No. 2000-271661 [0009]
[Problems to be solved by the invention]
However, since the press working method described in JP-A-2000-271661 requires two die shoulders at different molding direction positions on the inner wall of the die, and one die shoulder needs to be a movable die, There was a drawback that the structure of the machining tool was complicated.
Further, the press working method described in Japanese Patent Application Laid-Open No. 2000-271661 has a tendency to reduce the rigidity of the movable die provided on the inner wall of the die, so that a sufficient pressing force is applied to the corner portion of the metal plate through the movable die. It is difficult to act, and the accuracy of the corner portion of the part taken out from the processing tool may be inferior to that of the fixed die.
[0010]
Therefore, the present invention is to solve the above-mentioned conventional problems, and can simplify the structure of the working tool used, and can be a metal plate material such as a high-tensile steel plate or the like, an aluminum alloy plate, etc. Even when a metal plate material having a small Young's modulus is used, it is possible to reduce the warpage of the wall portion, and to provide a press working method excellent in shape freezing property capable of obtaining a highly accurate cross-sectional hat-shaped part. For the purpose.
[0011]
[Means for Solving the Problems]
The present invention is as follows.
1. Using a processing tool equipped with a punch, a die and a wrinkle presser, when performing press working to form a metal plate into a cross-sectional hat shape, at least two steps of the die shoulder are fixed to the inner wall from the mouth to the bottom of the die. The first die shoulder is the one located closest to the mouth side, and the second die shoulder is the one located on the mouth side next to the first die shoulder. Both ends of the metal plate in the width direction are sandwiched between the die face surface and the receiving surface of the wrinkle holding member, and after the wrinkle holding force is applied, the punch is pushed into the center portion in the width direction of the metal plate to start forming the first die. Drawing is performed while bending and bending back both ends in the width direction of the metal plate by the shoulder, and forming the wall of the metal plate by the second die shoulder during or after the drawing. And then the metal The die edge portion of the metal plate is formed by the second die shoulder portion in a state where both end portions in the width direction of the die face surface and the receiving surface of the wrinkle holding member are not applied with wrinkle holding force, and the punch flange A press working method excellent in shape freezing property, wherein the metal plate is clamped by a bead provided on a facing surface and a flange facing surface of the die.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a press working method according to an embodiment of the present invention will be described with reference to the drawings. In addition, as shown in FIGS. 1-4, the processing tool which fixed the shoulder part of the die | dye 2 steps | paragraph to the inner wall from the mouth of the die 2 to the bottom as shown in FIGS. In the following description, it is assumed that press forming is performed.
[0013]
However, what is located on the mouth side of the die 2 shown in the figure is referred to as a first die shoulder portion 5 and is located on the mouth side next to the first die shoulder portion 5, that is, the die shown in FIGS. In the case where two stages of die shoulders are provided from the mouth to the bottom of the two, the one located on the bottom side of the die 2 is referred to as a second die shoulder 6.
First, the working tool used in the press working method according to the embodiment of the present invention will be described with reference to FIG. The processing tool includes a punch 1, a die 2, and a wrinkle presser 3.
[0014]
In FIG. 1, A indicates the width dimension of the first stage of the punch 1, and B indicates the length dimension of the first stage of the punch 1. The punch 1 is a stepped punch in which a stepped portion is formed at a position B from the front end surface. The width dimension A of the first stage of the punch 1 is matched with the target shape of the part, and the length dimension B of the first stage of the punch 1 is matched with the molding height of the part. Further, C indicates a width direction interval between the inner walls on the bottom side of the die 2, and D indicates a width direction interval between the inner walls on the mouth side of the die 2. As described above, the inner wall of the die 2 is formed with a step in the middle so that the mouth side is wider than the bottom side.
[0015]
Here, the die face surface 7 is a surface of the die 2 that can sandwich the metal plate 4 with the receiving surface of the wrinkle presser 3 and can apply a wrinkle presser force. The first die shoulder 5 is connected to the die face surface 7 and fixed to the inner wall on the mouth side of the die 2. On the other hand, the second die shoulder 6 is fixed to the inner wall step on the bottom side of the die 2. Further, a flange facing surface 8 is formed on the inner wall step portion on the bottom side of the die 2 so as to be connected to the second die shoulder portion 6. When the die edge portion of the metal plate 4 is formed by the second die shoulder 6 after the molding process shown in FIG. 4, the flange facing surface 8 of the die 2 is made to face the flange of the die 2. It is formed so as to be housed within the width L of the surface 8. On the other hand, a flange facing surface 9 is formed at the step portion of the punch 1 so as to correspond to the flange facing surface 8 of the die 2. On the flange-facing surface 8 of the die 2, a protrusion 21 is provided, while on the flange-facing surface 9 of the punch 1, a groove 22 corresponding to the protrusion 21 is provided. A pair of beads is constituted by the convex strips 21 and the strip grooves 22.
[0016]
As shown in FIG. 4, the width-direction interval C between the inner walls on the bottom side of the die 2 is set such that the wall portion of the metal plate 4 can be formed by inserting the first stage of the punch 1 therein. Yes. Further, the width direction interval D between the inner walls on the mouth side of the die is set to C + 2 × L according to the width L of the flange facing surface of the die 2.
The wrinkle retainer 3 is connected to a hydraulic cylinder (not shown) via a rod, and as the die 2 descends, the metal plate 4 is clamped between the die face surface 7 and the receiving surface of the wrinkle retainer 3 to provide a wrinkle retaining force. It is possible. The pressing force can be set to an appropriate value by a pressure adjustment valve that adjusts the pressure of the hydraulic pressure in the hydraulic cylinder.
[0017]
1-4, the code | symbol 10 has shown the moving direction of the die | dye 2 in the formation process which shape | molds the metal plate 4 in cross-sectional hat shape.
As described above, the machining tool used in the present invention has a simple structure in which the die shoulder is fixed to at least two stages on the inner wall of the die.
Next, a press working method according to an embodiment of the present invention using the above-described working tool will be described.
[0018]
FIG. 1 is a schematic longitudinal sectional view showing a state in which the metal plate 4 is in contact with the front end surface of the punch 1, and FIG. 2 is a die shoulder portion in which both end portions in the width direction of the metal plate 4 are located on the mouth side of the die. 5 is a schematic longitudinal sectional view showing a state in which bending and bending back processing is performed by No. 5. FIG. FIG. 3 is a schematic longitudinal sectional view showing a state immediately before both ends in the width direction of the metal plate 4 are released from the wrinkle pressing force application state, and FIG. 4 is a diagram illustrating the position of the wall portion of the metal plate 4 on the bottom side. It is a schematic longitudinal cross-sectional view which shows the state currently shape | molded by the die shoulder part 6. FIG. The metal plate 4 is formed into a cross-sectional hat shape through a forming process as shown in FIGS.
[0019]
As shown in FIGS. 1 and 2, the press working method according to the embodiment of the present invention applies wrinkle pressing force by sandwiching both ends in the width direction of the metal plate 4 between the die face surface 7 and the receiving surface of the wrinkle presser 3. After the state, the die 2 is lowered, the punch 1 is pushed into the center of the metal plate 4 in the width direction, and forming is started, and the first die shoulder 5 is bent and bent back at both ends of the metal plate 4 in the width direction. Drawing is performed while applying. Further, by lowering the die 2, as shown in FIGS. 3 and 4, the forming of the wall portion of the metal plate 4 is started by the second die shoulder portion 6 immediately after the drawing forming is finished, and a wrinkle holding force is applied. The wall portion of the metal plate 4 is formed by the second die shoulder 6 in a state where it is not.
[0020]
Next, the die 2 is further lowered from the state shown in FIG. 4, and both ends in the width direction of the metal plate 4 are separated from the die face surface 7 and between the receiving surfaces of the wrinkle presser 3 and no wrinkle holding force is applied. Then, the die edge portion of the metal plate 4 is formed by the second die shoulder portion 6 and the metal plate 4 is clamped by a pair of beads provided on the flange facing surface 8 of the die 2 and the flange facing surface 9 of the punch 1 to form the metal plate 4. End the process.
[0021]
Thereafter, the die 2 is raised, and the metal plate 4 formed into a cross-sectional hat shape is taken out from the processing tool to form a part.
In the present invention, the bending thickness moment in the wall portion of the metal plate 4 caused by bending and bending back at the die shoulder, which is the main cause of warping of the wall portion of the hat-shaped part, is obtained. Reduced the wall warpage of parts.
[0022]
FIG. 5 shows an example of the relationship between the die shoulder radius and the curvature of the wall portion of the component when the wrinkle holding force is applied and the drawing is performed. The curvature on the vertical axis is defined by 1 / the radius of curvature. The larger the radius of curvature is, the closer the curvature is to 0, and the smaller the curvature of the wall of the obtained part.
From the results shown in FIG. 5, it can be seen that the warpage of the wall can be reduced by increasing the die shoulder radius. According to the present invention, as described above, the first die shoulder portion 5 that performs drawing and the second die shoulder portion 6 that molds the wall portion and the die edge portion are separated. It can be seen that by increasing the shoulder radius of the die shoulder portion 5, it is possible to reduce the warpage of the wall portion of the component without changing the shape of the die edge portion.
[0023]
On the other hand, the conventional die shoulder is connected to the die face on the inner wall of the die only at one location, and the function of bending and unbending the metal plate and the shape of the die edge part of the part are final. Since it has both the function of forming automatically, the shape and size of the die shoulder cannot be determined freely.
Even when the first die shoulder radius is smaller than, for example, the second die shoulder radius that determines the product shape, the size of the wrinkle pressing force is adjusted as appropriate to reduce the radius. It is possible to obtain a warp reduction effect at the vertical wall. This is because the metal plate is not completely wound around the first die shoulder, and the actual metal plate bending radius is larger than the first die shoulder radius.
[0024]
In the case of normal hat bending forming as shown in FIG. 9, the clearance between the die and the punch is set to about 1.0 to 1.4 times the normal plate thickness, and the metal plate is located between the die and the punch. Even if the wrinkle holding force is set low, the metal plate is appropriately wound around the die shoulder and the bending radius of the metal plate is almost the same as the die shoulder radius. Therefore, when the die shoulder radius is small, the warp of the vertical wall portion becomes large according to the die shoulder radius. On the other hand, in the present invention, the die shoulder is configured in two steps, and the clearance between the vertical wall of the die just above the first die shoulder, which is the portion through which the metal plate passes, and the punch is wide. By appropriately setting, the winding of the metal plate around the die shoulder can be eased, the bending radius of the metal plate can be easily made larger than the die shoulder radius, and the vertical wall warp can be reduced.
[0025]
In the present invention, the metal plate 4 is clamped by a pair of beads provided on the flange facing surface 8 of the die 2 and the flange facing surface 9 of the punch 1 to reduce the warp of the wall portion of the component. As described above, the pair of beads is constituted by the ridges 21 and the grooves 22. FIG. 6 is a schematic diagram for explaining the effect of reducing the warpage of the wall portion of the component according to the present invention. FIG. 6A is a view of a metal plate subjected to bending and unbending at the die shoulder by a conventional pressing method. The stress distribution of a wall part is shown typically. On the other hand, (b) schematically shows the stress distribution in the wall portion of the metal plate 4 when the metal plate 4 is clamped with beads by the press working method of the present invention. Note that the stress distribution of the wall portion of the metal plate 4 shown in FIG. 6B is a distribution in a portion subjected to bending and unbending processing at the first die shoulder portion 5 on the mouth side of the die.
[0026]
In the case of the conventional press working method, as shown in FIG. 6A, the stress distribution state is such that tensile stress is unevenly distributed on one side in the plate thickness direction of the wall portion of the metal plate and compressive stress is unevenly distributed on the other side. Therefore, the warp of the wall part was large.
On the other hand, according to the present invention, since the portion of the metal plate 4 pressed by the ridges 21 constituting the bead is pushed into the groove 22 constituting the bead, the stress distribution in the wall portion of the metal plate 4 is achieved. 6B is in a tensile stress state as shown in FIG. 6B. As a result, when the metal plate 4 formed from the processing tool is taken out and used as a part, the warp of the wall portion becomes smaller than in the conventional case. This is because the bending moment around the center of the plate thickness caused by the tensile stress distribution shown in FIG. 6B is more than the bending moment around the center of the plate thickness caused by the stress distribution shown in FIG. Because it is small. Thus, according to this invention, the curvature of the wall part of components can be reduced.
[0027]
Here, in the press working method of the present invention, the drawing is performed while bending and bending back both ends in the width direction of the metal plate 4 by the first die shoulder portion 5 in a state where the wrinkle pressing force is applied. This is to prevent the generation of wrinkles at both ends in the width direction of the metal plate 4 and the generation of wrinkles at the wall portions of the metal plate 4. On the other hand, when forming the metal plate 4 while bending and bending back the both ends in the width direction of the metal plate 4 by the first die shoulder 5 without applying the wrinkle holding force, both ends in the width direction of the metal plate 4 are applied. Wrinkles are generated in the wall portion and the wall portion of the metal plate 4, and a part having excellent surface quality cannot be obtained.
[0028]
By the way, the molding direction interval H between the first die shoulder 5 and the second die shoulder 6 is warped so as not to be less than the length B dimension of the first stage of the punch, which is the molding height. It is desirable from the viewpoint of reduction. The reason for this is that when the molding direction interval H between the first die shoulder 5 and the second die shoulder 6 is less than the molding height B, the second die shoulder is applied with a wrinkle holding force applied. This is because the molding of the wall portion of the metal plate is started by 6. When the wall portion of the metal plate is formed in such a state that the wrinkle pressing force is applied, the wall portion is also formed by bending and bending back the metal plate 4 even at the second die shoulder portion 6. Therefore, the warp reduction effect of reducing the warp of the wall portion of the component is slightly reduced.
[0029]
However, if the interval H exceeds the forming height B dimension, both ends in the width direction of the metal plate 4 are released from the wrinkle holding force application state, and then the wall portion of the metal plate by the second die shoulder 6. From the point of view of production cost, the interval H is the dimension of the molding height B because not only a useless stroke that does not perform molding occurs but also the mold becomes larger and the cost increases. The following is preferable. Therefore, the distance H may be set appropriately in consideration of the dimensional accuracy allowed for the parts, the mold cost, and the like. At that time, the appropriate value of the forming direction interval H between the first die shoulder 5 and the second die shoulder 6 is determined by the shape of the part to be manufactured, the thickness of the metal plate material used, the material, and the press. It can be determined by conducting a preliminary experiment or the like according to the processing conditions.
[0030]
In addition, the width | variety of the metal plate material used for this invention is the width | variety of the metal plate 4 when the die | dye 2 is lowered | hung from the shaping | molding state shown in FIG. The direction end portion does not protrude from the flange facing surfaces 8 and 9 in the width direction, and is determined based on the shape of the punch or the above-described experiment so that the width of the flange portion of the target part can be obtained. it can.
[0031]
In addition, the shape of the pair of beads provided on the flange-facing surfaces of the punch 1 and the die 2 that are the processing tools used in the present invention is not limited to the above-described semicircular shape, and various cross-sectional shapes can be used. For example, it may be triangular in cross section. Of course, it is also possible to form a pair of beads by providing a convex strip 21 on the flange facing surface 9 of the punch 1 used in the present invention and providing a corresponding groove 22 on the flange facing surface 8 of the die 2.
Moreover, the bead provided in the punch and die | dye used for this invention is not limited to a pair. The size and number of beads provided on the flange-facing surfaces of the punch and die used in the present invention are the bending moment around the center of the plate thickness generated in the wall portion of the metal plate when the metal plate 4 is clamped by the bead. What is necessary is just to determine so that tension | tensile_strength which can be reduced and can reduce the curvature of the wall part of components is obtained. However, when an excessive tension is generated on the wall portion of the metal plate, the metal plate may be broken. Therefore, it is desirable to provide an appropriate bead for obtaining the minimum necessary tension. An appropriate bead can be determined by a preliminary experiment or the like according to the shape of the part to be manufactured and the thickness and material of the metal plate material to be used. In the above description, the case where the die shoulder portions are fixed to the inner wall between the mouth and the bottom of the die is described as being fixed in two steps, but the number of die shoulder portions is not limited to this, and more It may be provided. In this case, the above-described processing may be performed with the first die shoulder as the first die shoulder and the second die shoulder as the second die shoulder next to the first die shoulder.
[0032]
【Example】
Using a processing tool equipped with punches, dies and wrinkle presses, a hat-shaped part with walls and flanges is manufactured by pressing, the dimensional accuracy of the part is examined, and the result is compared with the conventional case. This is shown in FIG.
Four types of metal plate materials were used: steel plates with a tensile strength of 270 MPa, 590 MPa, and 980 MPa, a plate thickness of 1.6 mm, and a 5000 series aluminum alloy plate with a plate thickness of 1.6 mm (Young's modulus: 70 GPa). .
[0033]
In the example of the invention, a stepped punch was used as the punch, and the first step width A was 50 mm, the first step length B was 60 mm, and the shoulder radius of the punch tip was 5 mm. The width of the second step of the punch was 86 mm, and the width of the flange facing surface of the punch was 18 mm corresponding to the flange facing surface of the die. On the other hand, as a die, at least two die shoulder portions are fixedly provided at the molding direction position of the inner wall of the die, the distance C between the inner walls on the bottom side of the die is 54 mm, and the width L of the die flange facing surface is 20 mm. The distance D between the inner walls on the mouth side of the die was 94 mm. Further, the molding direction interval H between the die face surface 7 and the die flange facing surface 8 is 30 mm, the radius of the first die shoulder portion on the die mouth side is 20 mm, and the second die shoulder portion on the bottom side of the die. The radius was 5 mm. Protruding strips having a semicircular cross section were provided on the flange-facing surface of the die, and a groove corresponding to the protruding strips was provided on the flange-facing surface of the punch to constitute a pair of beads. The radius of the ridges and grooves was 2 mm.
[0034]
The molding height of the parts was set to 60 mm, and the length of the flange part of the parts was set to 15 mm. The dimensional accuracy of the parts was evaluated by measuring the inner spacing of the wall at a position of 50 mm downward from the hat head after taking out the molded body from the tool, and evaluating the error with respect to the punch width. The wrinkle holding force was 20 kN.
As a conventional example, the processing tool shown in FIG. 9 was used, the same metal plate material as that of the invention example was used, and the forming height was set to 60 mm. However, the punch used the punch without a level | step difference, the width of the punch was 50 mm, and the shoulder radius of the front-end | tip part of the punch was 5 mm. As the dice, the inner walls of the dice were formed straight, the distance between the inner walls of the dice was 54 mm, and the radius of the die shoulder portion of the dice was 5 mm. The punch, die, and wrinkle presser were made of the same material as in the invention.
[0035]
From the result of the dimensional error of the part shown in FIG. 7, in the case of the conventional example, the dimensional error of the part wall part is large. On the other hand, in the case of the invention example, the dimensional accuracy of the part wall part is better than the conventional example. I know that there is. Also, even when using a metal plate material with high strength or a metal plate material with a low Young's modulus, the dimensional error of the wall of the component can be reduced, and the dimensional accuracy of the component due to variations in the material strength of the metal plate material It has been found that it is also effective in reducing the variation of.
[0036]
【The invention's effect】
According to the present invention, the working tool to be used can have a simple structure, and even when a metal plate material having a high strength or a metal plate material having a low Young's modulus is used, the warpage of the wall portion can be reduced. In addition, a cross-sectional hat-shaped part with high dimensional accuracy can be obtained. As a result, when a structural member is formed using a hat-shaped component, the assembly of the component can be easily performed, and a structural member for automobiles with high dimensional accuracy can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a forming process of a press working method according to the present invention, and is a schematic longitudinal sectional view showing a state where a metal plate is in contact with a front end face of a punch.
FIG. 2 is an explanatory view showing the forming process of the press working method according to the present invention, in which bending and unbending are performed by a die shoulder portion in which both ends in the width direction of the metal plate are located on the mouth side of the die. It is a schematic longitudinal cross-sectional view which shows the state which has received the process.
FIG. 3 is an explanatory view showing the forming process of the press working method according to the present invention, and schematically showing a state immediately before the both ends in the width direction of the metal plate are released from the wrinkle holding force application state. It is a longitudinal cross-sectional view.
FIG. 4 is an explanatory view showing a forming process of the press working method according to the present invention, and shows a state in which a wall portion of a metal plate is formed by a die shoulder located on the bottom side of the die. It is a schematic longitudinal cross-sectional view shown.
FIG. 5 is a graph showing the relationship between the die shoulder radius of the die and the curvature of the wall of the part.
FIG. 6 is a schematic diagram for explaining the effect of reducing the warpage of the wall portion of the component by the bead.
FIG. 7 is a graph showing the dimensional accuracy of a metal plate part manufactured by the pressing method of the present invention in comparison with a conventional example.
8A is a perspective view showing the shape of a metal plate part, and FIG. 8B is a front view.
9A and 9B are explanatory diagrams of a conventional press working method.
FIGS. 10A, 10B, and 10C are explanatory diagrams of a press working method when a moving die is used.
[Explanation of symbols]
1 punch 2 die 3 wrinkle retainer 4 metal plate 5 first die shoulder (die shoulder on the mouth side)
6 Second die shoulder (bottom die shoulder)
7 Die-face surface 8 Flange facing surface of die 2 9 Flange facing surface of punch 1
10 Direction of die movement
21 ridges
21 groove
11 parts
12 Hat head
13 Wall
14 Flange
15 Die edge A First width B of punch 1 First length C of punch 1 Width distance D between inner walls on the bottom side of the die 2 Width distance L between inner walls on the mouth side of the die 2 Width H of flange facing surface Forming direction interval between first die shoulder and second die shoulder

Claims (1)

Using a processing tool equipped with a punch, a die and a wrinkle presser, when performing press working to form a metal plate into a cross-sectional hat shape, at least two steps of the die shoulder are fixed to the inner wall from the mouth to the bottom of the die. The first die shoulder is the one located most on the mouth side, the second die shoulder is the one located on the mouth side next to the first die shoulder,
First, both ends of the metal plate in the width direction are sandwiched between a die face surface and a receiving surface of the wrinkle holding member, and then a wrinkle holding force is applied. Then, the punch is pushed into the widthwise center portion of the metal plate to start forming, Drawing is performed while bending and bending back both ends in the width direction of the metal plate with one die shoulder, and during the drawing or after drawing, the wall of the metal plate is formed with the second die shoulder. Part molding started,
Next, in a state where both end portions in the width direction of the metal plate are separated from the die face surface and between the receiving surfaces of the wrinkle holding member and no wrinkle holding force is applied, the die edge portion of the metal plate is held by the second die shoulder portion. A press working method excellent in shape freezing property, characterized in that the metal plate is clamped by a bead provided on the flange facing surface of the punch and the flange facing surface of the die while being molded.

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