Technical field
[0001]
　The present invention is a press working apparatus, stamping method, and a press-molded product, particularly, a press working apparatus for obtaining a molded article comprising a U-shaped portion in cross section, a press working method, and by such apparatus or method obtained press-molded product on.
Background technique
[0002]
　Elongated channel member, and the hat-shape members are formed by press working, for example, it is commonly used as a frame member such as a vehicle. The frame member of the vehicle, a high strength to ensure the collision safety and vehicle body rigidity is required. Further, also the cup shape members axisymmetric to be molded by press working, for example, are commonly used as a rotary member such as a drum or hub in the transmission of the vehicle. A rotary member also high strength is required to withstand the torque transmitted.
[0003]
　The above-mentioned channel member, and the hat-shape members, and the cup shape members are all have in common that they comprise a U-shaped portion in cross section. U-shaped portion includes a corner portion between the vertical wall, ceiling, and the vertical wall portion and a ceiling portion. If such strength members are required as described above, it is necessary to plate thickness of members in the U-shaped portion is sufficiently secured. Therefore, for example, as described in Patent Document 1, the distance between the die and the punch in the press working is larger than the thickness of the workpiece, the vertical wall portion after the outline of the U-shaped portion is formed of by pushing an end portion, increasing the thickness of the whole (to increase meat) technology of the U-shaped portion including the corner portion is known.
CITATION
Patent Literature
[0004]
Patent Document 1: JP 2009-208149 JP
Summary of the Invention
Problems that the Invention is to Solve
[0005]
　In the above-described conventional art, when pushed the end of the vertical wall portion, by flowing the material between the vertical wall portion and a ceiling portion, thereby thickening the entire U-shaped portion. Therefore, the outer corner portion in a shape having a curvature, and it is necessary to some extent the curvature radius, the point was to design constraints. Further, in order to increase meat as a whole a U-shaped portion, for example, processing such as to thickening only corner portions to a desired thickness is difficult.
[0006]
　The present invention has been made in view of the above problems, it is an object of the present invention, in the press working to obtain a molded article comprising a U-shaped portion in section, freely corner molding capable of realizing a new and improved pressing apparatus, to provide a press-forming method, and press-molded product.
Means for Solving the Problems
[0007]
　In order to solve the above problems, according to an aspect of the present invention, there is provided a pressing device for obtaining a molded product by press working of the workpiece, moldings ceiling, vertical wall, and the ceiling portion clamping the U-shaped portion comprising a corner portion comprises a cross section, a die with a recess formed to receive the U-shaped portion, the central region of the ceiling portion between the bottom surface of the recess between the vertical wall portion first and punch, is pressed into the recess later than the first punch, while restraining the vertical wall portion with the side face of the recess, the ceiling portion sandwich the workpiece between the bottom surface of the peripheral region and the corner portion and a second punch for shaping, the first punch for holding the central region of the ceiling portion pinching widths, and, from the first punch in the second punch in the pressing direction retraction amount is set based on the target thickness of the corner portion, flop Be machined apparatus is provided.
[0008]
　In the press working apparatus, the workpiece is a plate-shaped at the beginning of press working, the first punch and the second punch by the first press is retracted second punch than the first punch the state while maintaining a flat workpiece pushed into the recess, may be formed a central region of the vertical wall portion and a ceiling portion.
[0009]
　Second punch is pushed into the recess by the second press working may be molded marginal region and the corner portion of the ceiling portion by sandwiching the workpiece between the bottom surface.
[0010]
　Also, pinching width of the first punch, and, erosion of the second punch has a cross-sectional area of ​​the tapered portion between the central region and the vertical wall portion of the ceiling portion being formed by the first press working, the 2 corners are formed by pressing may be set so that the cross-sectional area of ​​the ridge portion of the molded article was the target thickness is matched.
[0011]
　For example, clamping width of the first punch, and, erosion of the second punch may be set so as to satisfy the following formula (A).
[0012]
[Equation 1]

　where, H 1 retraction of the second punch, W 1 is the length of the tapered portion in the width direction, Rp is the radius of curvature of the inner corner portion, t is the thickness of the workpiece .
[0013]
　In the press working apparatus, moldings may be an elongated member having a U-shaped portion to form a channel-shaped, may be axisymmetric member U-shaped portion to form a cup shape. Further, the corner portion may be shaped to thickness than the vertical wall portion and a ceiling portion increases. Outside corners may be formed at substantially right angles.
[0014]
　The above pressing apparatus, the corner portions of the vertical wall portion is abutted against the end face of the opposite side may further include a third punch which is pressed toward the bottom surface after molding of the corner portion.
[0015]
　In order to solve the above problems, according to another aspect of the present invention, there is provided a press-forming method for obtaining a molded product by press working of the workpiece, moldings ceiling, the vertical wall portion, and it includes a U-shaped portion consisting of a corner portion between the ceiling portion and the vertical wall portion in cross-section, a first pressing step of the first punch to clamp the central region of the ceiling portion between the bottom surface of the recess , the second punch is pressed into the recess of the die later than the first punch, while restraining the vertical wall portion with the side face of the recess, ceiling sandwich the workpiece between the bottom surface and a second pressing step of forming the marginal regions and the corner portion of the part, the first punch clamping width for holding the central region of the ceiling portion, and the first punch in the second punch in the pressing direction amount of recession, sets of on the basis of the target thickness of the corner portion from And that, pressing method is provided.
[0016]
　Workpiece is a plate-shaped at the beginning of pressing, in the first pressing step, the first punch and the second punch, remain second punch is retracted than the first punch the was left plate-shaped workpiece pushed into the recess, it may be formed a central region of the vertical wall portion and a ceiling portion.
[0017]
　In a second stamping operation, the second punch is pressed into the recess may be molded marginal region and the corner portion of the ceiling portion by sandwiching the workpiece between the bottom surface.
[0018]
　Pinching width of the first punch, and, erosion of the second punch has a cross-sectional area of ​​the tapered portion between the central region and the vertical wall portion of the ceiling portion being formed by the first press working, the second press processed by may be set so that the corner portion is molded and cross-sectional area of ​​the ridge portion of the molded article was the target thickness is matched.
[0019]
　For example, clamping width of the first punch, and, erosion of the second punch may be set so as to satisfy the following formula (B).
[0020]
[Equation 2]

　Here, H 1 retraction of the second punch, W 1 is the length of the tapered portion in the width direction, Rp is the radius of curvature of the inner corner portion, t is the thickness of the workpiece .
[0021]
　Moreover, the press working method, prior to the first pressing step may include a heating step of heating the workpiece to a predetermined temperature.
[0022]
　Moreover, the press working method, prior to the first pressing step, the recess formed in the die may further include a receiving step of receiving the U-shaped portion of the molded article.
[0023]
　Press-forming method includes a ceiling portion, and a vertical wall portion, a molded article comprising a U-shaped portion consisting of a corner portion in the cross section as the second workpiece, in a shape corresponding to the shape of the second molded article there are, a recess for accommodating the second workpiece, and a second die that supports the ceiling portion of the at least a second workpiece, the ceiling portion together with the second die the second workpiece using a fourth punch for clamping and pushing the end surface of the vertical wall portion of the second workpiece, and a fifth punch for forming the second molded product, a second pressing device provided with, in a state in which the ceiling portion of the second workpiece is sandwiched by the second die and the fourth punching, by the fifth punch press the end surface of the vertical wall portion of the second workpiece, the second molded product additional forming step of forming a may further include.
[0024]
　Here, the recess of the second die of the second pressing device, the length between a plane corresponding to the vertical wall portion of the second workpiece is, the outer surface of the vertical wall portion of the second workpiece is formed to be larger than the length between, in addition the molding step, in a state in which the ceiling portion of the second workpiece is sandwiched by the second die and the fourth punching, the second workpiece by a fifth punch push the end face of the vertical wall portion, a vertical wall portion of the second workpiece may be thickened.
[0025]
　Alternatively, among the second die of the second pressing device, a portion that supports the ceiling portion of the second workpiece, supported and fixed die for supporting the central region, the end of the vertical wall portion constitute a movable die which is movable in the extending direction, in addition the molding process, in a state in which the ceiling portion of the second workpiece sandwiched by the second die and the fourth punching, the by fifth punch push the end surface of the vertical wall portion of the second workpiece, by moving the movable die, it may be formed a Tatekabenobe portion that extends in the vertical wall.
[0026]
　Also, of the second die of the second pressing device, the part supporting the vertical wall portion of the second workpiece, in a position corresponding to the ceiling portion of the second workpiece, the vertical wall forming a stepped portion recessed in the direction away from the part, in addition the molding process, in a state in which the ceiling portion of the second workpiece sandwiched by the second die and the fourth punching, the by fifth punch push the end face of the vertical wall portion of the second workpiece may be formed ceiling extending portion that extends to the ceiling.
[0027]
　Further, the corner between the further according to another aspect, is formed by press working of the workpiece, the ceiling portion, the vertical wall portion, and a ceiling portion and a vertical wall portion of in order to solve the above problems, the present invention the U-shaped portion consisting of part a press molded article comprising a cross-section, the corner portion is vertical wall part and the plate thickness than the ceiling portion is larger press-molded product is provided. Further, according to still another aspect of the present invention, is formed by press working of the workpiece, the ceiling portion, the vertical wall portion, and a U-shaped portion consisting of a corner portion between the ceiling portion and the vertical wall portion a press molded article comprising a cross-section, the outer corners are substantially right, the press-molded product is provided.
[0028]
　Here, the curvature radius R1 of the inner corner portion, the curvature of the outer corner radius R2, the thickness t of the ceiling portion and the vertical wall portion of the workpiece, so as to satisfy the relationship of the following formula (C) it may be.
　　　R2 ≦ R1 + t ··· (C )
[0029]
　The hardness of the corner portion of the press-molded product is higher than the hardness of the workpiece.
[0030]
　For example, the hardness of the corner portion of the press-molded product is more than 1.5 times the hardness of the workpiece.
[0031]
　Further, the ceiling portion of the press-molded article, a central region, located between the central region and the corner portion consists of a peripheral region is a region within a predetermined distance from the corner portion, and the central area and the peripheral area the hardness of the boundary portion is higher than the hardness of the workpiece is lower than the hardness of the corner portion.
[0032]
　Here, the predetermined distance from the corner portion may be determined based on the thickness of the workpiece, and the radius of curvature of the inner corners.
[0033]
　The central region of the ceiling portion of the press-molded product is a region which is formed by the first press working, the side edge region of the ceiling portion of the press-molded product is molded by the second pressing after the first pressing area it may be.
[0034]
　Further, the thickness of the vertical wall portion of the press-molded product may be greater than the thickness of the ceiling portion.
[0035]
　Press-molded product may further comprise a Tatekabenobe portion of the vertical wall portion is extended.
[0036]
　Alternatively, the press-molded product may further comprise a ceiling extending portion of the ceiling portion is extended.
Effect of the invention
[0037]
　According to the present invention described above, in the press working to obtain a molded article comprising a U-shaped portion in cross section, it is possible to realize a free shaping of the corner portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038]
FIG. 1 is a schematic cross-sectional view showing the configuration of a pressing device together with the operation at the time of press working in accordance with the first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing the configuration of a pressing device together with the operation at the time of press working in accordance with the first embodiment of the present invention.
3 is a schematic cross-sectional view showing the configuration of a pressing device together with the operation at the time of press working in accordance with the first embodiment of the present invention.
4 is a schematic cross-sectional view showing the configuration of a pressing device together with the operation at the time of press working in accordance with the first embodiment of the present invention.
5 is a diagram for explaining a dimension related to the shape of the workpiece after the second press.
[FIG 6A] is a diagram for explaining an example of the shape of the corner portion in the cross section of the molded article molded by press working apparatus according to a first embodiment of the present invention.
[FIG 6B] is a diagram for explaining an example of the shape of the corner portion in the cross section of the molded article molded by press working apparatus according to a first embodiment of the present invention.
[7] for a part of the corner portion and the ceiling portion of the workpiece which is formed by pressing a diagram showing a plastic strain distribution.
Is a graph showing the hardness distribution of the workpiece shown in FIG. 8 Fig.
Is a diagram illustrating an example of a molded article according to the first embodiment of FIG. 9A] present invention.
Is a diagram illustrating an example of a molded article according to the first embodiment of FIG. 9B] present invention.
It is a schematic sectional view showing the operation of the press working apparatus according to a modification of the first embodiment of FIG. 10 the present invention.
11 is a schematic sectional view showing the operation of the press working apparatus according to a modification of the first embodiment of the present invention.
12 is a diagram for explaining an example of a molded article of the cross-sectional shape which is formed by press working apparatus according to another modification of the first embodiment of the present invention.
13 is a schematic cross-sectional view of the structure of the pressing device along with operation at the time of press working in accordance with another modification of the first embodiment of the present invention.
14 is a schematic cross-sectional view of the structure of the pressing device along with operation at the time of press working in accordance with another modification of the first embodiment of the present invention.
15 is a schematic cross-sectional view of the structure of the pressing device along with operation at the time of press working in accordance with another modification of the first embodiment of the present invention.
16 is a schematic cross-sectional view showing along with operation at the time of constituting the deep drawing of the press working apparatus according to the prior art.
17 is a schematic cross-sectional view showing along with operation at the time of constituting the deep drawing of the press working apparatus according to the prior art.
FIG. 18 is a schematic cross-sectional view showing as well as the operation of the time structure pressing the pressing device (deep drawing) according to the second embodiment of the present invention.
FIG. 19 is a schematic cross-sectional view showing as well as the operation of the time structure pressing the pressing device (deep drawing) according to the second embodiment of the present invention.
FIG. 20 is a schematic cross-sectional view showing as well as the operation of the time structure pressing the pressing device (deep drawing) according to the second embodiment of the present invention.
FIG. 21 is an explanatory diagram showing an example of a molded article is formed by pressing according to a third embodiment of the present invention.
22 is a schematic sectional view showing an initial state of the press working which thickened the vertical wall portion.
[Figure 23] press working which thickened the vertical wall portion, is a schematic sectional view showing a state after the thickening of the vertical wall portion.
FIG. 24 is an explanatory diagram showing an example of a molded article is formed by pressing according to a fourth embodiment of the present invention.
[25] is a schematic sectional view showing an initial state of the press working to extend the vertical wall portion.
FIG. 26 is a schematic sectional view showing a state of extension after casting of the vertical wall portion.
FIG. 27 is an explanatory diagram showing an example of a molded article is formed by pressing according to a fifth embodiment of the present invention.
FIG. 28 is a schematic sectional view showing an initial state of the press working to extend the ceiling.
FIG. 29 is a schematic sectional view showing a state of extension after casting of the ceiling portion.
[FIG. 30] is an explanatory view showing a molding method for press molding a channel shape having a flange to be tested in the Examples.
[FIG. 31] is a perspective view of the press-molded product to be tested in the Examples.
[FIG. 32] is a front view of the press-molded product to be tested in the Examples.
[FIG 33 is an explanatory view showing the shape of the press-molded product to be tested in the Examples.
FIG. 34 is an explanatory view illustrating a 3 rolling bending test.
Is a graph showing the FIG. 35 thickness increase rate of the press-molded product used in Test 1-5 and maximum load ratio.
DESCRIPTION OF THE INVENTION
[0039]
　Reference will now be described in detail preferred embodiments of the present invention. In the specification and drawings, components having substantially the same function and structure, might be omitted duplicate by referring to the figures in the drawings.
[0040]
　(1. First Embodiment corner thickening of)
　(. 1-1 Operation of the press working apparatus)
　1 to 4, press the configuration of the first press working apparatus according to the embodiment of the present invention is a schematic cross-sectional view showing as well as the operation at the time of processing. Referring to FIGS. 1-4, the press working apparatus 100 includes a die 120 and a punch 140. Die 120 includes a stationary die 122 and a movable die (pad) 124. Punch 140 includes a stationary punch 142, and outer movable punch (pad) 144 and an inner movable punch (pad) 146. That is, the punch 140 includes an inner movable punch 146 as the first punch, the outer movable punch 144 as the second punch, and a fixed punch 142 as the third punch.
[0041]
　As shown in FIG. 1, at the start of the pressing of the present embodiment, workpiece 10 is a flat plate. Movable die 124, the cushion 128 coupled to the bottom of the recess 126 formed in the fixed die 122, the upper surface is supported so as to be in contact with the workpiece 10. On the other hand, the punch 140, the inner movable punch 146 is in contact with the central portion of the workpiece 10, sandwiching the workpiece 10 between the upper surface of the movable die 124. Outer movable punch 144 includes a cushion 148 that is connected to the fixed punch 142, by a cushion 150 connected to the inner movable punch 146, retracted by a predetermined retraction amount than the inner movable punch 146 (i.e., the workpiece 10 and farther from the die 120) is supported in position.
[0042]
　After the start of the pressing, the punch 140 is pressed toward the bottom surface of the recess 126 (first press), first cushion 128 is contracted, the movable die 124, the work piece between the inner movable punch 146 10 It is pushed into the left recess 126 and sandwiching the central portion. Thus the cushion 148, 150 does not shrink at the time, the punch 140, the outer movable punch 144 is pushed into the recess 126 while maintaining the retracted position relationship than the inner movable punch 146. That is, the outer movable punch 144 will be pushed into the recess 126 later than the inner movable punch 146.
[0043]
　As shown in FIG. 2, when the movable die 124 has bottomed against the recess 126, the center of the workpiece 10 that is pushed into the recess 126 in a state of being sandwiched between the movable die 124 and the inner movable punch 146 part of the ceiling portion 14a (the central region of the ceiling portion 14 to be finally formed), vertically edges of the workpiece 10 that is folded between the side surface 130 of the outer movable punch 144 and the recess 126 with it the wall portion 12, outline of the U-shaped portion is formed.
[0044]
　Here, in this embodiment, the vertical wall portion 12 is captured between the side surface 130 of the outer movable punch 144 and the recess 126. That is, in the press working apparatus 100, the outer movable punch 144, the distance between the side surface 130 is designed to substantially match the thickness of the workpiece 10. Further, at the time when the movable die 124 is pushed inwardly the movable punch 146 has a bottom against the recess 126, since the outer movable punch 144 is pushed into the recess 126 later than the inner movable punch 146, the ceiling portion 14a and the vertical tapered portion 16 is formed between the wall portion 12.
[0045]
　As shown in FIG. 3, further followed by a punch 140 is pressed (second press), turn the cushion 150 is deflated, the inner movable punch 146 movable outer punch 144 is further pushed into the recess 126 catch up to. At this time, the outer movable punch 144 sandwich the workpiece 10 (tapered portion 16) between the bottom surface 132, a ceiling portion 14b (the side edge region of the ceiling), and a ceiling portion 14 and the vertical wall portion 12 molding a corner portion 18 between. Here, as is apparent by referring to FIGS. 2 and 3, in the cross section of the workpiece 10, the length of the tapered portion 16, than the combined length of the marginal region 14b and the corner portion 18 of the ceiling portion also long. Therefore, the pressing device 100, thereby thickened corner portions 18, that is, it is possible to mold the corner portion 18 as the plate thickness than the vertical wall portion 12 and the ceiling 14 is increased.
[0046]
　As shown in FIG. 4, as an additional step, after this, it may be further pressed toward the punch 140 to the bottom 132 of the recess 126. In this case, the cushion 148 is deflated, the fixed punch 142 is pushed into the recess 126. Fixed punch 142 is in contact with the end face 19 of the vertical wall portion 12, thereby further thickening the corner portion 18 by pushing the vertical wall portion 12 between the outer movable punch 144 and the side surface 130. The end face 19, of the end portion of the vertical wall portion 12, it is a surface of the end located on the opposite side of the corner portion 18. In the example shown, between the fixed punch 142 and the outer movable punch 144 and side 130 and bottom 132 by pushing the vertical wall portion 12 is filled, the outer corners 18 are formed at substantially right angles.
[0047]
　In the press working apparatus 100 for processing in this manner the workpiece 10, the length of the tapered portion 16 which is formed by the first press is longer than the combined length of the marginal region 14b and the corner portion 18 of the ceiling portion is processed so as to shape the corner portion 18 as the plate thickness than the vertical wall portion 12 and the ceiling 14 is increased. Therefore, to define the length of the tapered portion 16, sandwiching the central region 14a of the ceiling portion 14 of the workpiece 10, the upper surface of the inner movable punch 146 nipped width, and, inside the outer movable punches 144 in the pushing direction it is necessary to retreat amount from the movable punch 146 is properly set. Specifically, the corner portion 18, the molded to plate thickness than the vertical wall portion 12 and the ceiling 14 is increased, the amount of workpiece material forming the tapered portion 16, the target corner portion 18 It suffices same or more and amount of the workpiece required for the plate thickness. That is, the cross-sectional area of ​​the tapered portion 16 is, if (the ridge portion described below corresponds) portion including the corner portion 18 formed from a tapered portion 16 cross-sectional area the same as or more, the target thickness of the corner portion 18 it can be equal to or greater than.
[0048]
　First, the cross-sectional area of ​​the portion including the corner portion 18 formed from the tapered portion 16 is calculated as follows. For such explanation, in FIG. 5 shows an example of the workpiece 10 after the second press shown in FIG. Figure 5 is a diagram for explaining a dimension related to the shape of the workpiece 10 after the second press.
[0049]
　The workpiece 10 after the second press, including as shown in FIG. 5, a vertical wall 12, a ceiling 14, and a corner portion 18. The workpiece 10 is assumed to be a plate thickness t of at every position. Further, the curvature radius inner corners 18 R p and the outer radius of curvature of the corner portion 18 R p and a + t. Then, it comprises a corner section 18 sets an S square that share the outside of the outer and the ceiling portion 14 of the vertical wall portion 12 of the workpiece 10. The length of one side of the region S, the thickness t and radius of curvature R p and is the sum of the. That is, the area S, the radius R p circle and the radius R of + t p circle is contained 1/4 respectively. Hereinafter also referred to as a ridge portion portions of the area S of the workpiece 10.
[0050]
　Sectional area S of the ridge portion shown in FIG. 5 A is represented by the following formula (1). Sectional area S of the ridge line portion of formula (1) A represents represents a sectional area of a single ridge, the cross-sectional area of the left or right of the edge line portion if, for example, FIG.
[0051]
[Number 3]

[0052]
　Also, when to perpendicular to the outer corner portion 18, the cross-sectional area S of the ridge line portion of the workpiece 10 B is represented by the following formula (2).
[0053]
[Formula 4]

[0054]
　On the other hand, the sectional area S of the tapered portion 16 T , as shown in FIG. 2, H the length of the tapered portion 16 of the push-in direction 1 , the length of the tapered portion 16 in the width direction W 1 When the following formula ( represented by 3). Sectional area S of the tapered portion 16 of the following formula (3) T also represents the cross-sectional area of one of the tapered portion 16, represents a cross-sectional area of the left or right of the tapered portion 16 if FIG. 2, for example there.
[0055]
[Formula 5]

[0056]
　From the above, the sectional area S of the tapered portion 16 T is, at least the formula (1) in cross-sectional area S is expressed A long or more, thereby thinning the thickness of the corner portion 18 from the plate thickness of the workpiece 10 it is eliminated. Further, to ensure that the outside of the corner portion 18 becomes substantially right angle, the cross-sectional area S of the tapered portion 16 T cross-sectional area S of the above formula (2) B may be to equal. Thus, the cross-sectional area S of the tapered portion 16 in accordance with a target thickness of the corner portion 18 T may be set.
[0057]
　In the press working apparatus 100, the sectional area S of the tapered portion 16 T length H of the tapered portion 16 in the pushing direction to define the 1 is from the inner movable punch 146 of the outer movable punches 144 in the pushing direction of the pressing device 100 corresponding to the amount of retreat. Further, the sectional area S of the tapered portion 16 T length W of the tapered portion 16 in the width direction to define the 1 is the difference between the width of the top surface of the width and the inner movable punch 146 of the recess 126 of the fixed die 122 1/2 corresponding to. The width of the upper surface of the inner movable punch 146 is a clamping width for clamping the central region 14a of the ceiling portion 14. Since the width of the recess 126 of the fixed die 122 is determined as the size of the molded article, the width direction length W of the tapered portion 16 1 is adjusted according to the width of the upper surface of the inner movable punch 146.
[0058]
　Accordingly, the sectional area S of the tapered portion 16 T has a retraction amount from the inner movable punch 146 of the outer movable punches 144 in the pushing direction of the pressing device 100, the width of the upper surface of the inner movable punch 146 (i.e., sandwiching width) and it is possible to have a predetermined size by adjusting the. Therefore, the cross-sectional area S of the tapered portion 16 by the target thickness of the corner portion 18 T is determined and the determined cross-sectional area S T as tapered portion 16 is obtained having, by configuring the press working apparatus 100, it can be a corner section 18 to obtain a thickness increase has been molded article.
[0059]
　(1-2. Moldings feature)
　FIGS. 6A and 6B for explaining an example of the shape of the corner portion of the molded articles of the cross-section formed by press working apparatus according to a first embodiment of the present invention it is a diagram. 6A is a corner portion 18 is an example that is shaped to thickness than the vertical wall portion 12 and the ceiling portion 14 is increased. 6B is an example in which the outer is formed substantially at a right angle of the corner portion 18.
[0060]
　As already mentioned, in the prior art, the material to flow between the vertical wall portion and a ceiling portion by increasing the radius of curvature of the outer corner portion, have to thickening the entire U-shaped portion of the cross section It was. In this case, the radius of curvature of the outer corner portion is small, the defects such as Orekomi by material flow is inhibited occurs. In contrast, in this embodiment, since after molding of the central region of the vertical wall portion 12 and the ceiling 14, the corner portion 18 is molded by squeezing the tapered portion 16 is outwardly movable punch 144, the vertical wall portion 12 and flow of the material between the ceiling portion 14 does not occur, thus reducing the outer radius of curvature of the corner portion 18, or can be substantially perpendicular to the outer corner portion 18.
[0061]
　As described above, in the example shown in FIG. 6A, the corner portion 18 of the workpiece 10 is shaped as a plate thickness than the vertical wall portion 12 and the ceiling portion 14 is increased. That is, in this example, the corner portions 18 are thickened. In this case, in the cross section of the workpiece 10, the outer radius of curvature R2 of the corner portion 18 is smaller than plus the thickness t of the vertical wall portion 12 and the ceiling portion 14 on the inner side of the curvature radius R1 (R2 R1 + t. Therefore, the corner portions 18 are thickened, the outer radius of curvature R2 of the corner portion 18 is smaller that the equivalent than plus thickness t on the inner side of the curvature radius R1.
[0062]
　As a specific example, a case thickness t of the vertical wall portion 12 and the ceiling portion 14 of the workpiece 10 is 5 mm, 0.5 mm outside radius of curvature R2 of the corner portion 18 (10% of the sheet thickness t) the inner radius of curvature R1 as 7.5 mm (1.5 times the sheet thickness t), it is possible to perform the press working without causing flaws. Incidentally, as in the example shown in FIG. 6B, since the outer corner portion 18 is also possible to a right angle, the radius of curvature R2 may be smaller than 0.5 mm. Although in relation to the prior art as described above advantages of the present embodiment when reducing the radius of curvature R2 is remarkable, in this embodiment by the outer radius of curvature R2 of the corner portion 18 is greater since applications are not intended to be inhibited, the radius of curvature R2 may be greater than 0.5 mm. The radius of curvature R1 inner corners 18, there is a possibility that defects due Orekomi of too large material occurs for a radius of curvature R2, at least the curvature radius R1 is the above relative thickness t when in range as an example, it is possible to carry out press working without causing flaws.
[0063]
　On the other hand, in the example shown in FIG. 6B, in the cross section of the workpiece 10, the outside of the corner portion 18 is formed at a substantially right angle. In the present specification, when "is outside a substantially right angle of the corner portion 18" is not only the case outside of the corner portion 18 is strictly perpendicular, as possible the outer radius of curvature of the corner portion 18 small, also included is close to 0. In this case, it is also possible to mold a substantially right angle also inside of the corner portion 18, from the viewpoint of avoiding stress concentration on the corner portion 18, (not the extent close to 0) some for inner corner portion 18 it is desirable to provide a radius of curvature R1. In this case, the outer radius of curvature of the corner portion 18 can be interpreted as less than plus thickness t on the inner side of the curvature radius R1. Therefore, in the example shown in FIG 6B, it can be said that the corner portion 18 is thickened.
[0064]
　Further, the workpiece which is formed by press working apparatus according to the present embodiment, the corner portion is harder than other portions. As an example, in FIGS. 7 and 8, when the 270MPa grade steel using a press working apparatus according to the present embodiment by press working, vertical wall portion, the results of measuring the hardness distribution of the corner portion and the ceiling portion . 7, for some of the corner portion and the ceiling portion of the workpiece which is formed by pressing a diagram showing a plastic strain distribution. Figure 8 is a graph showing the hardness distribution of the workpiece shown in FIG. In Figure 8, the hardness at 200μm position in the thickness direction from the outer surface of the workpiece, was measured in each 1mm each toward the vertical wall portion and a ceiling portion side from the corner portion. Hardness is expressed in Vickers hardness, the harder the larger the value. The measurement distance w is the origin position of the corner portion, represents the ceiling direction in a positive value represents a vertical wall direction by a negative value.
[0065]
　Thickness before pressing of the workpiece of the present embodiment is 1.6 mm, (referred to hereinafter as "material hardness".) Its hardness HV 0 was 85. Tapered portion formed by the first press working, a length of 10mm, push-in direction of the length of 10mm in the width direction. Then, after forming the marginal area of the corner portion and the ceiling portion by a second pressing, the hardness at 200μm position in the thickness direction from the outer surface of the workpiece, the vertical wall portion and a ceiling portion side from the corner portion It was measured every 1mm each toward the.
[0066]
　From plastic strain distribution shown in FIG. 7, it can be seen that the strain is large in some of the corner portion and the ceiling portion. Looking at the hardness distribution of the workpiece, as shown in FIG. 8, the hardness at the home position representing the corner portion is higher than other portions. Although hardness decreased toward a ceiling portion side from the home position is higher again hardness measurement distance at a position of about 10 mm. Thus, the workpiece that is formed by press working apparatus according to the present embodiment, a corner portion, at a ceiling portion of a position away from the corner portion by a predetermined distance, becomes harder than the material hardness. In these positions, since plastic strain is increased, it is believed that work hardening is increased.
[0067]
　As shown in FIG. 8, in this example, material hardness HV 0 whereas it is 85, the hardness of the corner portion (measurement distance w = 0) is 212, material hardness HV 0 about the It was 2.5 times. Also, the hardness of the ceiling portion at a position away of 10mm from the corner section (measured distance w = 10mm) is 127, material hardness HV 0 was about 1.5 times. Thus, the corner portion, in a ceiling portion of the position apart from the corner portion by a predetermined distance, the hardness becomes high. The hardness of the corner portion is higher than the ceiling of the position apart from the corner portion by a predetermined distance. Here, the ceiling portion of the position apart from the corner portion by a predetermined distance, corresponding to a boundary portion between the marginal region and the central region of the ceiling portion.
[0068]
　More specifically, adjacent to the portion which is sandwiched by the inner movable punch in the recess of the die by the first press working, corresponding to the ceiling-side end region of the tapered portion. Because the central region of the ceiling portion which is sandwiched by the first press working, material hardness HV 0 is maintained almost hardness of the ceiling portion end region of the tapered portion is not sandwiched by the first pressing. Therefore, the second press working is carried out after the first pressing, is considered that the work hardening in the ceiling portion end region of the tapered portion occurs. Therefore, the workpiece which is formed by press working apparatus according to the present embodiment has a hardness distribution as shown in FIG.
[0069]
　As a comparison, for example, forming the corner portion by one press working, stress takes concentrated in the corners, plastic strain occurs only in the corners. On the other hand, when forming the corner portion by press working of a multi-stage such as in a press working apparatus according to the present embodiment, the central region of the ceiling portion by a first pressing element hardness HV 0 can substantially maintain the hardness of further , a load of the second pressing after the first pressing, easily dispersed throughout the tapered portion which is formed in the first pressing. Therefore, the stress in the corner portion molded from the tapered portion can be prevented from concentrating, the load at the time of molding the marginal area of the corner portion and the ceiling portion from the tapered portion can be reduced.
[0070]
　Incidentally, the workpiece of the present embodiment is 270MPa grade steel, although a large mild steel work hardening properties, for example, even a small steel plate work hardening ability such as a high tensile steel, and the corner portion, the distance from the corner portion of the predetermined in a ceiling portion of the remote position alone, tendency hardness becomes high appears as well. In this case, than mild steel, such as in this example, the rate of increase in the hardness of the ceiling portion of the position away from the tapered portion and the corner portion by a predetermined distance decreases. Specifically, the hardness of the corner portion, material hardness HV 0 1.5 times, the hardness of the ceiling portion of the position apart from the corner portion by a predetermined distance, material hardness HV 0 1 a .1 times.
[0071]
　9A and 9B are diagrams showing an example of a molded product in this embodiment. Elongated shaped article 50 shown in the example of FIG. 9A, includes a channel-shaped 52. Channel shape 52 includes a vertical wall portion 54, and a ceiling portion 56. In this example, (including a U-shaped portion) cross section of the workpiece 10 as shown in FIGS. 3 and 4 corresponds to the A-A cross section of the molded article 50 shown in Figure 9A. Also, in this example, the pressing device 100, the recess 126 formed in the die 120 has a groove, the bending of the workpiece 10 is performed by using the die 120 and the punch 140 become.
[0072]
　On the other hand, the molded article 60 of the axisymmetric shape shown in the example of FIG. 9B includes a cup-shaped 62. Cup-shaped 62 includes a vertical wall portion 64, and a ceiling portion 66. In this example, (including a U-shaped portion) cross section of the workpiece 10 as shown in FIGS. 3 and 4 corresponds to section B-B of the molded article 60 shown in Figure 9B. Also, in this example, the pressing device 100, the recess 126 formed in the die 120 forms a hole, that the drawing of the workpiece 10 is performed by using the die 120 and the punch 140 become.
[0073]
　Molded articles 50 and 60 described above are both shaped by pressing, a molded article comprising a U-shaped portion in cross section. These moldings, for example, as described above, characterized in that corner portions of the U-shaped portion is thickened or outer corners, is substantially perpendicular seen. Incidentally, as will be described later in detail, especially when the molded article has a cup-shaped may thinning occurs in the corner portion in the molding process of the U-shaped portion of the cross section. If inhibited thinning by applying the present embodiment in such a case, the radius of curvature of the outer corner portion of the molded product, or the same as those obtained by adding thickness to the inner radius of curvature, than It can also have it smaller.
[0074]
　(1-3. Modification)
　FIG. 10 and FIG. 11 is a schematic sectional view showing the operation of the press working apparatus according to a modification of the first embodiment of the present invention. In this modified example, by processes similar to those described with reference to FIGS. 1 and 2 above, the vertical wall portion 12 and the ceiling portion 14a constituting the U-shaped portion of the cross-section of the workpiece 10 is molded that (for this step are not shown since already described). Subsequently, the punch 140 is further pressed toward the bottom surface 132, the outer movable punch 144 by the cushion 150 is contracted is further pushed into the recess 126. At this time, the outer movable punch 144 is already made to catch up with the inner movable punch 146 that sandwich the ceiling portion 14a between the bottom surface 132, in this modification, as shown in FIG. 10, the outer movable before the punch 144 to catch up with the inner movable punch 146, the outer corners 18 formed by push the tapered portion 16 of the workpiece 10 is in close contact with the side surface 130 and bottom surface 132 of the recess 126, is substantially perpendicular there.
[0075]
　Thereafter, the punch 140 is further is pressed toward the bottom surface 132, by the inner corner portion 18 is widened by the outer movable punch 144, the vertical wall portion 12 is pushed upward. At this time, the fixed punch 142 is pushed up to the end surface 19 of the vertical wall portion 12 is retracted relative to the outer movable punch 144. That is, in this modification, the fixed punch 142, the example shown in FIG. 4 above the end face 19 to the reverse motion. As a result, as shown in FIG. 11, the inside of the corner portion 18 is molded along the outer movable punch 144, forming of the workpiece 10 is completed.
[0076]
　In this modification, for example, to adjust the length of the tapered portion 16 by setting the difference between the positions of the outer movable punch 144 and the inner movable punch 146 at the beginning of the pressing process (initial length of the cushion 150), FIG above 4 without performing an additional press with fixed punch 142 as in the example shown, are substantially at right angles forming the outer corner portion 18. In this case, in the course of the press by outer movable punch 144, there is a possibility that the vertical wall portion 12 by excess material at the corner portion 18 is pushed up. In such a case, as described above, by allowing an increase of the vertical wall portion 12 while pressing the end face 19 at a fixed punch 142 can be molded well end face 19 precision.
[0077]
　Figure 12 is a diagram for explaining an example of a molded article of the cross-sectional shape which is formed by press working apparatus according to another modification of the present embodiment. In the example shown in FIG. 12, by tapering towards the outside of the punch 140 to the lower surface of the outer movable punch 144, other than the central region Ra of the ceiling portion 14 of the workpiece 10 that is formed by the outer movable punch 144 and gradually thickening the regions Rb toward the central region Ra in the corner portion 18. In this case, by the change in thickness between the ceiling portion 14 and the corner portion 18 becomes gentle, it is possible to relieve the stress concentration on the corner portion 18.
[0078]
　(1-4. Conclusion)
　In the first embodiment of the present invention described above, in the press working of the workpiece 10 using the pressing device 100, the outer movable punch 144 is delayed from the inner movable punch 146 by being pushed into the recess 126, the tapered portion 16 is formed between the vertical wall portion 12 and the ceiling portion 14a. Longer than the length of the tapered portion 16 is a length tailored finally the ceiling portion formed marginal area 14b and the corner portion 18 is, by forming the corner section 18 push the tapered portion 16, longitudinal even the material between the wall 12 and the ceiling portion 14 is not necessary to flow can be thickened corner portions 18. Therefore, in the present embodiment, it is possible conventionally to reduce the outer radius of curvature of the corner portion 18 as compared to the art, or substantially to a right angle outer corners 18. In addition, without having to increase the meat of the vertical wall portion 12 and the ceiling portion 14, it can also be thickened only the corner portion 18.
[0079]
　In the press working apparatus 100 according to the present embodiment, in a series of pressing steps of pushing the punch 140, pushing in the recess 126 of the outer movable punch 144 by the action of the cushion 150 later than the inner movable punch 146, thereby which enables a free shaping of the corner portion 18. Therefore, the pressing device 100 may be a uniaxial pressing apparatus multiaxial press independently a plurality of portions of the punch each other is not required.
[0080]
　In the example described above, the pressing from the state workpiece 10 is a flat plate shape as shown in FIG. 1 is started, the present embodiment is not limited to such an example. For example, be implemented in other devices as steps primary molding for molding the vertical wall portion 12 and the ceiling portion 14a forms a U-shaped portion of the workpiece 10 (central region), followed by the press working apparatus 100 two as a next molding, for example, as shown in FIG. 2 above, it may be press working is started from a state where the U-shaped portion of the cross-section of the workpiece 10 is received in the recess 126. In this case, the movable die 124 may not necessarily be provided. Further, the present embodiment, the pressing for cross obtain a molded article having a hat-shaped portion further includes a flange portion continuous to the end portion of the vertical wall portion 12 (end portion opposite to the corner portion 18) It can also be applied.
[0081]
　: (. 1-5 supplemented when put curvature on the outside of the corner portion)
　as another modification of the first embodiment of the present invention, for example, in a recess formed in the die, the corner between the side surface and the bottom surface it may be formed in the surface. By shaping the workpiece along the corner surface, the outer corner between the vertical wall portion and a ceiling portion, it is possible to precisely process into a shape with a curvature. The following describes press forming when attaching the curvature on the outside of the corner portion. Since the other points are the same as those in the first embodiment, duplicate description is omitted.
[0082]
　13 to 15 are schematic cross-sectional view of the structure of the pressing device along with operation at the time of press working in accordance with another modification of the first embodiment of the present invention. Referring to FIGS. 13 to 15, the press working apparatus 200 includes a die 220 and a punch 140. Die 220 includes a stationary die 222 and a movable die (pad) 224. The configuration of the punch 140 is the same as the first embodiment described above.
[0083]
　As shown in FIG. 13, at the start of the pressing of the present embodiment, workpiece 20 is a flat plate. Movable die 224, the cushion 228 which is connected to the bottom of the recess 226 formed in the fixed die 222, the upper surface is supported so as to be in contact with the workpiece 20. On the other hand, the punch 140, as in the first embodiment described above, the inner movable punch 146 is in contact with the central portion of the workpiece 20, clamping the workpiece 20 between the upper surface of the movable die 224 are doing. The outer movable punch 144 is supported at a position recessed from the inner movable punch 146.
[0084]
　After the start of pressing, clamping the punch 140 is pressed toward the bottom surface of the recess 126, the cushion 228 is contracted first, the movable die 224, the central portion of the workpiece 20 between the inner movable punch 146 It is pushed into the the left recess 226. Like the first embodiment, the punch 140 is movable outer punch 144 is pushed into the recess 126 while maintaining the retracted position relationship than the inner movable punch 146. Thus, the outer movable punch 144 will be pushed into the recess 226 later than the inner movable punch 146.
[0085]
　As shown in FIG. 14, when the movable die 224 has bottomed against the recess 226, the center of the workpiece 20 that is pushed into the recess 226 in a state of being sandwiched between the movable die 224 and the inner movable punch 146 the Department ceiling 24a (central region of the ceiling portion 24 to be finally formed), vertically edges of the workpiece 20 that is folded between the side surface 230 of the outer movable punch 144 and the recess 226 with it the wall portion 22, outline of the U-shaped portion is formed.
[0086]
　Here, as a difference from the first embodiment, in this embodiment, between the bottom surface 232 and side surface 230 of the recess 226, the corner surface 234 having a curvature is interposed. Bottom 232 is formed by the movable die 224 by bottoming, sides 230 and corner surface 234 is formed by the fixed die 222. Accordingly, in this embodiment, the outer dimensions of the movable die 224, by the amount of the corner surfaces 234 is smaller than the internal dimension of the recess 226. Although outer movable punch 144 in the present embodiment is a tapered portion 26 is formed by being pressed into the recess 126 later than the inner movable punch 146, the tapered portion 26 is not in contact with the corner surface 234.
[0087]
　As shown in Figure 15, further followed by a punch 140 is pressed, turn the cushion 150 is contracted, catch up with the inner movable punch 146 movable outer punch 144 is further pushed into the recess 226. At this time, the outer movable punch 144 sandwich the workpiece 20 (tapered portion 26) between the bottom surface 232 and corner surface 234, a ceiling portion 24b (the side edge region of the ceiling), and forming the corner portion 28 to. The inner corner portion 28 along the outer movable punch 144, outside along the corner surface 234 of the recess 226, are formed respectively. Since corner surface 234 is a surface having a curvature, the outer corners 28 are also formed into a shape having a curvature.

The scope of the claims
[Claim 1]
　A press working apparatus for obtaining a molded product by press working of the workpiece, the moldings ceiling portion, the vertical wall portion, and a U-shaped consisting of a corner portion between the ceiling and the vertical wall portion include Jo partial cross section,
　a die recess for receiving the U-shaped portions are formed,
　a first punch for holding the central region of the ceiling portion between the bottom surface of the recess,
　said first later than the punch is pressed into the recess, thereby constraining the vertical wall portion between the side surface of the recess, side edge region of the ceiling portion by sandwiching the workpiece between the bottom surface and a second punch for forming the corner portion
includes a
　first punch clamping width for holding the central region of the ceiling portion, and the first punch of the in pushing direction second punch amount of retreat from, the target of the corner section Based on the thickness is set, the press working apparatus.
[Claim 2]
　Said workpiece, said a pressing flat at the beginning of,
　the first punch and the second punch, the second punch is recessed from the first punch by a first press pushing the left of the plate-shaped workpiece remains in the recess, forming the vertical wall portion and the central region of the ceiling portion, a press working apparatus according to claim 1.
[Claim 3]
　The second punch is pressed into the recess by the second press working, shaping the marginal region and the corner portion of the ceiling portion by sandwiching the workpiece between said bottom surface, claim press processing apparatus according to 2.
[Claim 4]
　It said first punch clamping width, and amount of retreat of the second punch has a cross-sectional area of ​​the tapered portion between the central region and the vertical wall portion of said ceiling portion which is formed by the first press working the corner portion is molded and cross-sectional area of ​​the ridge portion of the molded article becomes the target thickness is set to coincide with the second press working, to any one of claims 1 to 3, press processing apparatus according.
[Claim 5]
　It said first punch clamping width, and the erosion of the second punch is set to satisfy the following formula (A), a press working apparatus according to claim 4.
[6]

　Here, H 1 is the amount of recession of the second punch, W 1 is the length of the tapered portion in the width direction, Rp is the radius of curvature of the inner side of the corner portion, t is the workpiece the plate is the thickness.
[Claim 6]
　The molded article, said U-shaped portion is an elongated member which forms a channel-shaped, the press working apparatus according to any one of claims 1 to 5.
[Claim 7]
　The molded article, said U-shaped portion is axially symmetrical member which forms a cup-shaped, press working apparatus according to any one of claims 1 to 5.
[8.]
　The corner portion, the plate thickness than the vertical wall portion and the ceiling portion is formed to be larger, the press working apparatus according to any one of claims 1 to 7.
[Claim 9]
　Outside of the corner portion is shaped substantially at right angles, the press working apparatus according to any one of claims 1-8.
[Claim 10]
　Wherein the said corner portion of the vertical wall portion is contact with an end face on the opposite side, further comprising a third punch which is pressed toward the bottom surface after molding of the corner portion, any one of claims 1-9 1 pressing apparatus according to claim.
[Claim 11]
　A press working method for obtaining a molded product by press working of the workpiece, the moldings ceiling portion, the vertical wall portion, and a U-shaped consisting of a corner portion between the ceiling and the vertical wall portion include Jo partial cross section,
　a first pressing step of the first punch to clamp the central region of the ceiling portion between the bottom surface of the recess of the die,
　the second punch than the first punch delay the pressed into the recess of the die, as well as restraining the vertical wall portion between the side surface of the recess, side edge region of the ceiling portion by sandwiching the workpiece between said bottom surface and Te a second pressing step of forming the corner portion
　comprises,
　the sandwiching a central region of the ceiling first punch pinching widths, and, from the first punch of the in pushing direction second punch amount of recession, the eyes of the corners of the It is set based on the plate thickness, the press working method.
[Claim 12]
　It said workpiece, said a flat at the beginning of press working,
　wherein in the first pressing step, the first punch and the second punch, the second punch said first punch pushing the plate-like workpiece while maintaining the retracted state into the recess than molding the vertical wall and the central region of the ceiling portion, the press working method according to claim 11.
[Claim 13]
　In the second pressing step, the second punch is pressed into the recess, forming the marginal region and the corner portion of the ceiling portion by sandwiching the workpiece between said bottom surface, press-forming method according to claim 12.
[Claim 14]
　It said first punch clamping width, and amount of retreat of the second punch has a cross-sectional area of ​​the tapered portion between the central region and the vertical wall portion of said ceiling portion which is formed by the first press working , any one of the second said corner portion which is formed by pressing and the cross-sectional area of ​​the ridge portion of the molded article becomes the target thickness is set to match, according to claim 11 to 13 press processing method according to.
[Claim 15]
　It said first punch clamping width, and the erosion of the second punch is set so as to satisfy the following formula (B), press-forming method according to claim 14.
[Expression 7]

　Here, H 1 is the amount of recession of the second punch, W 1 is the length of the tapered portion in the width direction, Rp is the radius of curvature of the inner side of the corner portion, t is the workpiece the plate is the thickness.
[Claim 16]
　Wherein prior to the first pressing step includes a heating step of heating the workpiece to a predetermined temperature, the press working method according to any one of claims 11-15.
[Claim 17]
　Wherein prior to the first pressing step, the recess formed in the die, further comprising a receiving step of receiving the U-shaped portion of the molded article, a press working method according to claim 11.
[Claim 18]
　And said ceiling portion, said vertical wall portion, the molded article comprising a U-shaped portion consisting of said corner portion in the cross section as the second workpiece,
　a shape corresponding to the shape of the second molded article Te, the second has a recess for accommodating the workpiece, and a second die that supports the ceiling portion of at least the second workpiece, the second workpiece with said second die a fourth punch to sandwich the ceiling portion of the timber, pushing the end surface of the vertical wall portion of the second workpiece, the second comprising a fifth punch for forming the second molded product, the using a pressing device,
　the ceiling portion of the second workpiece while sandwiched by the second die and the fourth punching, by the fifth punch of said second workpiece push the end face of the vertical wall portion, further comprising an additional forming step of forming the second molded product, wherein Press-forming method according to any one of 11-17.
[Claim 19]
　Wherein said recess of said second die of the second pressing device, the length between the second surface corresponding to the vertical wall portion of the workpiece is, the longitudinal of said second workpiece is formed larger than the length between the outer surface of the wall portion,
　in a state in said additional molding step, which sandwiches the ceiling portion of the second workpiece in the second die and the fourth punching, the push the end face of the vertical wall portion of the fifth punch by said second workpiece, and thereby thickening the vertical wall portion of the second workpiece, press working method according to claim 18.
[Claim 20]
　Of the second die of the second pressing device, wherein the portion for supporting the ceiling portion of the second workpiece includes a fixed die for supporting the central region, to support the ends, the longitudinal consists of a extending direction movable in the movable die of the wall,
　the said additional molding step, while sandwiching the ceiling portion of the second workpiece in the second die and the fourth punching, push the end face of the vertical wall portion of the second workpiece by said fifth punch, by moving the movable die to form a Tatekabenobe portion that extends in the vertical wall portion, press-forming method according to claim 18.
[Claim 21]
　Of the second die of the second pressing device, wherein the second portion for supporting the vertical wall portion of the workpiece, a position corresponding to the ceiling portion of the second workpiece in the and stepped portion recessed in the direction away from the vertical wall portion is formed,
　in the additional molding step, the ceiling portion of the second workpiece in the second die and the fourth punching in a sandwich state, the first through fifth punch push the end face of the vertical wall portion of the second workpiece, to form a ceiling extending portion that extends to the ceiling, according to claim 18 press working method.
[Claim 22]
　Is formed by press working of the workpiece, the ceiling portion, the vertical wall portion, and a U-shaped portion consisting of a corner portion between the ceiling and the vertical wall portion a press-formed article comprising the cross-
　a corner portion is larger thickness than the vertical wall portion and the ceiling portion, the press-molded product.
[Claim 23]
　Is formed by press working of the workpiece, the ceiling portion, the vertical wall portion, and a U-shaped portion consisting of a corner portion between the ceiling and the vertical wall portion a press-formed article comprising the cross-
　a outside corners are substantially right, the press-molded product.
[Claim 24]
　The radius of curvature R1 of the inner side of the corner portion, the outer radius of curvature R2 of the corner portion, the the plate thickness t of the ceiling and the vertical wall portion of the workpiece satisfies the following relationship formula (C), press molded article according to claim 22 or 23.
　　　R2 ≦ R1 + t ··· (C )
[Claim 25]
　The hardness of the corner portion of the press-molded product is higher than said hardness of the workpiece, the press molded article according to any one of claims 22-24.
[Claim 26]
　The hardness of the corner portion of the press-molded product, said at least 1.5 times the hardness of the workpiece, the press molded article according to claim 25.
[Claim 27]
　It said ceiling portion of the press-molded article, a central region, located between the central region and the corner portion consists of a peripheral region is a region within a predetermined distance from the corner portion,
　and the central region the hardness of the boundary between the peripheral region, the higher than the hardness of the workpiece is lower than the hardness of the corner portion, the press-molded product according to any one of claims 22-26.
[Claim 28]
　Predetermined distance from the corner portion, the and the plate thickness of the workpiece, said determined based on the radius of curvature inside of the corner portion, the press molded article according to claim 27.
[Claim 29]
　The central region of the ceiling portion of the press-molded product is a region which is formed by the first press working,
　the side edge region of the ceiling portion of the press-molded article, the second pressing after the first pressing is a region which is formed by press-molded article according to claim 27 or 28.
[Claim 30]
　Thickness of the vertical wall portion, the greater the thickness of the ceiling portion, a press molded article according to any one of claims 22-29.
[Claim 31]
　The vertical wall portion further comprises a Tatekabenobe portion that extends, press-formed article according to any one of claims 22-29.
[Claim 32]
　Further comprising a ceiling extending portion of the ceiling portion is extended, the press molded article according to any one of claims 22-29.