JP6665612B2 - Method for manufacturing press-formed product and press device - Google Patents

Description

  The present invention relates to a method for manufacturing a press-formed product and a press apparatus.

  2. Description of the Related Art An automobile body is assembled by overlapping edges of a large number of molded panels and joining them by spot welding to form a box, and joining structural members to key points of the box by spot welding. For example, as a structural member, a side sill joined to both sides of a floor panel, an A-pillar lower and an A-pillar upper erected at the front of the side sill are provided on the side (body side) of the body of the automobile, A roof rail joined to the upper end of the A pillar upper, and further a B pillar joined to the side sill and the roof rail are used.

  Components of structural members such as an A pillar lower, an A pillar upper, and a roof rail (for example, respective outer panels) generally include a top plate extending in a longitudinal direction and two top plates connected to both sides of the top plate. It is composed of a protruding ridge portion, two vertical walls connected to the two protruding ridge portions, two concave ridge portions connected to the two vertical walls, respectively, and two flanges connected to the two concave ridge portions, respectively. It often has a substantially hat-shaped cross-sectional shape.

  The components described above have a relatively complex cross-sectional shape and are elongated. Therefore, in order to suppress an increase in manufacturing cost, the above-described components are generally manufactured by cold press molding. Further, in order to achieve both reduction in weight and improvement in strength of a vehicle body for improving fuel efficiency, a reduction in thickness using, for example, a high-tensile steel plate having a tensile strength of 440 MPa or more as the above-mentioned structural member has been promoted.

  However, the high-strength steel sheet is cold-pressed to be curved in the longitudinal direction, for example, as in a roof rail outer panel (hereinafter referred to as a roof member. The roof member is a structural member of an automobile). When an attempt is made to manufacture a component, springback may occur at the time of release from the press die, and the top plate may be twisted. As a result, there arises a problem of shape freezing in that the roof member cannot be formed into a desired shape.

  For example, Patent Literature 1 discloses an invention in which when a press-formed product having a uniform hat-shaped cross section in the longitudinal direction is manufactured, a step is provided to suppress the occurrence of a mouth opening to enhance shape freezing. It has been disclosed.

  Patent Document 2 discloses that when manufacturing a press-formed product having a top plate, a vertical wall, and a flange and bending in the longitudinal direction, the flange formed in the first step is bent back in the second step to form the flange. An invention that enhances shape freezing by reducing residual stress is disclosed.

JP 2004-31423 A Patent No. 5382281

  According to the invention disclosed in Patent Document 1, when a press-formed product having a shape curved in the longitudinal direction thereof, such as a component of a component of an A-pillar lower, an A-pillar upper and a roof rail, is manufactured, a spring after release is released. The back causes the curved wall to bend and cannot be formed into a desired shape.

  According to the invention disclosed in Patent Document 2, when a press-formed product curved in the longitudinal direction and the height direction is manufactured, the residual stress of the flange, the residual stress in the plane of the vertical wall and the top plate, and the surface of the vertical wall and the top plate are reduced. Deviation residual stresses occur within. As a result, the press-formed product is bent as viewed from the top plate side (bend in the short direction of the top plate) due to springback after release, and cannot be formed into a desired shape.

  An object of the present invention is to provide a method for manufacturing a specific press-formed product in which the occurrence of bending as viewed from the top plate side is suppressed. Here, the specific press-formed product is a long top plate, ridge portions at both ends in the short direction of the top plate, and each end faces each other in a state where one end is connected to the ridge portion, at least one of which is the aforementioned It refers to a press-formed product including a pair of vertical walls that are curved walls that are curved when viewed from above the top plate (hereinafter, the same applies in the present specification).

  The method for manufacturing a press-formed product according to the present invention is characterized in that the long top plate, the ridge portions at both ends in the short direction of the top plate, and each end face each other with one end connected to the ridge portion, and Is a method of manufacturing a press-formed product including a pair of vertical walls and a curved wall that is curved as viewed from above the top plate, pressing a blank, the top plate, Including a pair of vertical walls, each of which has a ridge portion at both ends and a curved wall which is opposed to each other in a state where one end thereof is connected to the ridge portion and at least one of which is curved when viewed from above the top plate. A first step of forming an intermediate molded product formed on the curved wall along a longitudinal direction of the top plate, wherein the stepped portion is configured and the vertical wall projects on the opposite side to the opposite side. Pressing the intermediate molded product, a portion of the curved wall on the other end side of the stepped portion And a second step of moving to the opposite side and the opposite side.

  The press device according to the present invention presses a blank, and the top plate, the ridge portions at both ends, and each end face each other in a state where one end is connected to the ridge portion, and at least one of the ridge portions is from above the top plate. A first pressing device that forms an intermediate molded product formed on a pair of vertical walls that are curved walls that are curved when viewed, and that presses the intermediate molded product to form an intermediate molded product other than the step portion on the curved wall. A second pressing device for moving the end portion to the opposite side to the opposite side.

  Further, the press device according to the present invention includes a first press device that presses a blank with a first die and a first punch to form an intermediate molded product, and a second die and a second punch that form the intermediate molded product. A press device comprising a second press device for pressing, wherein the first die has a long first bottom surface, and one end thereof is connected to an end of the first bottom surface in a short direction, and is opposed to each other. An elongated first groove including the first side surface is formed, and at least one of the first side surfaces is curved as viewed from the mold closing direction, and the first groove extends the facing width of the first side surface. One step portion is a first curved surface formed over the longitudinal direction of the first side surface, and the shape of the first punch is a shape that fits with the shape of the first groove when the mold is closed. 1 press device, the second die has a long second bottom surface, and each end has a short side of the second bottom surface. A long second groove that is connected to the end in the direction and includes a second side surface facing each other, at least one of the second side surfaces is curved when viewed from a mold closing direction, and the second side surface is curved. A second curved surface having a second step portion formed at a position corresponding to the one step portion, and a portion of the second curved surface on the other end side of the second step portion inclined with respect to the mold closing direction; The angle of the second punch is greater than the angle at which the portion of the first curved surface on the other end side of the first stepped portion is inclined with respect to the mold closing direction, and the shape of the second punch is A second press device having a shape that fits into the shape of the second groove.

  By using the method for manufacturing a press-formed product according to the present invention, it is possible to manufacture a specific press-formed product in which occurrence of bending in the short direction due to springback from a desired shape of the specific press-formed product is suppressed.

  ADVANTAGE OF THE INVENTION By using the press apparatus which concerns on this invention, the specific press molded product in which generation | occurrence | production of the bending in the short direction by spring back from the desired shape of a specific press molded product can be suppressed can be manufactured.

FIG. 2 is a perspective view of the roof member according to the first embodiment, including a cross-sectional view in a longitudinal direction. FIG. 2 is a cross-sectional view of the roof member according to the first embodiment, and is a cross-sectional view taken along line 2-2 in FIG. 1. FIG. 2 is a perspective view of the intermediate molded product of the first embodiment, including a cross-sectional view in a longitudinal direction. FIG. 4 is a cross-sectional view of the intermediate molded product according to the first embodiment, which is a cross-sectional view taken along line 4-4 in FIG. 3. FIG. 5 is a schematic diagram in which a part (two-dot chain line) of the cross-sectional view of FIG. 2 is superimposed on a part (solid line) of the cross-sectional view of FIG. 4. It is a perspective view of the metallic mold of the 1st press device used by the 1st process in the manufacturing method of the roof member of 1st Embodiment. FIG. 2 is a cross-sectional view of a first press device and a blank used in a first step in a method of manufacturing a roof member according to the first embodiment. It is a perspective view of the metallic mold of the 2nd press device used by the 2nd process in the manufacturing method of the roof member of 1st Embodiment. It is a cross-sectional view of the 2nd press device used in the 2nd process in the manufacturing method of the roof member of 1st Embodiment, and an intermediate molded product. It is a figure for explaining a bending evaluation method. It is the figure of the roof member of 2nd Embodiment, Comprising: It is the perspective view shown including the cross-sectional view in the longitudinal direction. It is a figure which shows the cross section of the roof member of 2nd Embodiment, Comprising: It is the 12-12 line sectional drawing in FIG. It is a figure for explaining an outside vertical wall change starting point and an inside vertical wall change starting point in an example and a comparative example. It is a table | surface which shows the evaluation result by the simulation about the bending of the roof member of the Example (Examples 1-19) of 1st Embodiment, and the bending of the roof member of a comparative example (Comparative Examples 1-6). It is a table | surface which shows the evaluation result by the simulation about the bending of the roof member of the Example (Example 20-37) of 2nd Embodiment, and the bending of the roof member of a comparative example (Comparative Examples 7-12).

≪Overview≫
Hereinafter, embodiments (embodiments) for carrying out the present invention will be described by exemplifying two embodiments (first and second embodiments). Next, examples will be described.

<< 1st Embodiment >>
Hereinafter, the first embodiment will be described. First, the configuration of the roof member 1 (see FIGS. 1 and 2) of the present embodiment will be described. Next, the configuration of the press device 17 (see FIGS. 6, 7, 8, and 9) of the present embodiment will be described. Next, a method for manufacturing the roof member 1 of the present embodiment will be described. Next, the operation of the present embodiment will be described. The roof member of the present embodiment corresponds to Example 9 in Examples described later (see FIG. 14).

<Configuration of roof member>
First, the configuration of the roof member 1 of the present embodiment will be described with reference to the drawings. Here, the roof member 1 is an example of a press-formed product and a specific press-formed product.

  As shown in FIGS. 1 and 2, the roof member 1 includes a top plate 2, two convex ridge lines 3 a, 3 b, two vertical walls 4 a, 4 b, two concave ridge lines 5 a, 5 b, The cross-sectional shape is a substantially hat-shaped elongate member integrally formed with the two flanges 6a and 6b. Here, the convex ridge lines 3a and 3b are examples of the ridge. As an example, the roof member 1 is a cold press-formed product made of a high-tensile steel sheet having a tensile strength of 1470 MPa class.

  The top plate 2 is long as shown in FIG. When viewed from above (the top plate 2), the top plate 2 extends in the longitudinal direction (the direction of the arrow L1 in the figure). The two convex ridge portions 3a and 3b are formed at both ends in the short direction of the top plate 2. The two vertical walls 4a and 4b face each other with one end connected to the protruding ridge portions 3a and 3b, respectively. That is, the roof member 1 of the present embodiment is a state in which the long top plate 2, the protruding ridge portions 3a, 3b at both ends in the short direction of the top plate 2, and one end are connected to the protruding ridge portions 3a, 3b. And vertical walls 4a and 4b opposed to each other. As shown in FIG. 1, the two vertical walls 4 a and 4 b are curved along the longitudinal direction of the top plate 2 when viewed from above the top plate 2. That is, at least one of the two vertical walls 4a and 4b of the present embodiment (both in the case of the present embodiment) is a curved wall that is curved when viewed from above the top plate 2. Here, the vertical wall 4a is an example of a curved wall. In the present embodiment, as an example, the vertical wall 4a is curved convexly toward the side opposite to the vertical wall 4b side (the side facing the vertical wall 4b side), and the vertical wall 4b is It is concavely curved toward the side opposite to the side facing the wall 4a).

  In addition, each cross section (transverse cross section) perpendicular to the longitudinal direction of the top plate 2 of the present embodiment extends linearly in the lateral direction at each position in the longitudinal direction as an example (see FIG. 1). That is, the top plate 2 of the present embodiment is flat at each position in the longitudinal direction when viewing the respective vertical cross sections in the longitudinal direction (see FIG. 2). Here, the convex ridge line portion 3a is a portion connecting the top plate 2 and the vertical wall 4a as shown in FIG. Is the part that is. Two dashed lines in the figure indicate both ends of the convex ridge line portion 3a connected to the top plate 2 and the vertical wall 4a, respectively. The convex ridge line portion 3b is a portion connecting the top plate 2 and the vertical wall 4b, although not shown at both ends by a one-dot chain line, and is curved when looking at each cross section perpendicular to the longitudinal direction of the top plate 2. Is the part that is.

  As shown in FIG. 2, the two concave ridge lines 5a and 5b are formed at the ends of the two vertical walls 4a and 4b, respectively, on the opposite side to the side connected to the top plate 2. The two flanges 6a, 6b are connected to two concave ridge portions 5a, 5b, respectively. The concave ridge line portion 5a is a portion connecting the vertical wall 4a and the flange 6a, although illustration of both ends by a dashed line is omitted. When looking at each cross section perpendicular to the longitudinal direction of the top plate 2, it is curved. Part. Further, the concave ridge line portion 5b is a portion connecting the vertical wall 4b and the flange 6b, and the cross section perpendicular to the longitudinal direction of the top plate 2 is curved. The part that is.

  As shown in FIG. 1, the roof member 1 is curved from one end 1a to the other end 1b in the longitudinal direction when viewed from the top plate 2 side. The roof member 1 includes a first portion 8 including one end 1a, a third portion 10 including the other end 1b, a second portion 9 connecting the first portion 8 and the third portion 10, and Can be said to be integrally configured.

  Here, in the present embodiment, when viewed from the top plate 2 side, the radius of curvature of the first portion 8 is, for example, 2000 (mm) or more and 9000 (mm) or less, and the radius of curvature of the second portion 9 is one example. Is set to 500 (mm) or more and 2000 (mm) or less, and the radius of curvature of the third portion 10 is set to 2500 (mm) or more and 9000 (mm) or less as an example.

  As shown in FIG. 2, the thickness center of the R starting point (R stop) of the convex ridge line portion 3a on the top plate 2 side, that is, from the thickness center of the top plate 2 to the concave ridge line portion 5a side of the vertical wall 4a. The height up to the end (the lower end of the vertical wall 4a) is defined as height h. Then, in the vertical wall 4a, a step portion 11a having a step amount a2 (mm) is formed in a portion separated from the center of the top plate 2 by 40% or more of the height h over the longitudinal direction. In addition, the height h 'is defined as the height of the center of the thickness of the R start point (R stop) of the convex ridge line portion 3b on the top 2 side, that is, the height from the thickness center of the top 2 to the lower end of the vertical wall 4b. . Then, a step portion 11a 'having a step amount a2' (mm) is formed on the vertical wall 4b at a portion separated from the center of the top plate 2 by at least 40% of the height h 'in the longitudinal direction. ing. In the present specification, the center of the top plate 2 in the thickness direction is a position in the height direction of the top plate 2. Note that the projecting widths a2, a2 'of the step portions 11a, 11a' are 20% or less of the width W of the top plate 2 at each position in the longitudinal direction of the top plate 2 in the short direction. .

  Of both ends of the step portion 11a, a portion closer to the top plate 2 (upper side) is defined as a concave portion 11a1, and a portion farther from the top plate 2 (lower side) is defined as a convex portion 11a2. Further, of the two ends of the step portion 11b, a portion closer to the top plate 2 (upper side) is defined as a concave portion 11a'1, and a portion farther from the top plate 2 (lower side) is defined as a convex portion 11a'2. Then, when generalizing both ends of the step portions 11a and 11a ', the following can be rephrased. Of the both ends of the step portion 11a, the concave portion 11a1 which is the end on the side (upper side) close to the top plate 2 is a portion that forms a radius of curvature that is the largest convex on the inner surface side on the inner surface of the vertical wall 4a, The protruding portion 11a2, which is an end farther (lower side) from the plate 2, is a portion that forms a radius of curvature that becomes the largest convex on the outer surface side on the inner surface of the vertical wall 4a. In addition, the concave portion 11a'1 which is the end (upper side) closer to the top plate 2 of both ends of the step portion 11a 'forms a radius of curvature which is the largest convex on the inner surface side of the inner surface of the vertical wall 4b. The projecting portion 11a'2, which is an end farther (lower side) from the top plate 2, is a portion that forms a radius of curvature that becomes the largest convex on the outer surface side on the inner surface of the vertical wall 4b. As shown in FIG. 2, when the cross section perpendicular to the longitudinal direction of the roof member 1 is viewed, the protrusion width a2 of the step portion 11a is different from the convex portion 11a2 and the concave portion 11a1 in the short direction of the top plate 2. Means the separation width. The protruding width a2 ′ of the step portion 11a ′ is, when viewed in a cross section perpendicular to the longitudinal direction of the roof member 1, the width of the separation between the convex portion 11a2 ′ and the concave portion 11a1 ′ in the short direction of the top plate 2. That means.

  In the roof member 1, the cross-sectional shapes of the flanges 6a and 6b are different between one end 1a and the other end 1b in the longitudinal direction (not shown). The angle of the flange 6b with respect to the vertical wall 4b is 30 ° at one end 1a and 40 ° at the other end 1b. The angles of the flanges 6a and 6b with respect to the vertical wall 4a are respectively continuously changed in the longitudinal direction. Further, the width of the top plate 2 in the short direction changes so as to continuously increase from one end 1a to the other end 1b in the longitudinal direction.

  The above is the description of the configuration of the roof member 1 of the present embodiment.

<Configuration of press device>
Next, the press device 17 of the present embodiment will be described with reference to the drawings. The press device 17 of the present embodiment is for manufacturing the roof member 1 of the present embodiment. The press device 17 is configured to include a first press device 18 and a second press device 19, as shown in FIGS. 6, 7, 8, and 9. In the press device 17 of the present embodiment, the first press device 18 is used to press-form the blank 25 (see FIG. 7) by drawing to form an intermediate molded product 30 (see FIGS. 3 and 4). The intermediate molded product 30 is press-formed by the second press device 19 to manufacture a product, that is, the roof member 1. The blank 25 is a long high-tensile steel plate which is a base material for manufacturing the roof member 1.

  Here, as shown in FIGS. 3 and 4, the intermediate molded product 30 includes a top plate 2, two convex ridge lines 3a, 3b, two vertical walls 33a, 33b, and two concave ridges 34a. , 34b and two flanges 35a, 35b. The two vertical walls 33a and 33b are formed with step portions 11a and 11a 'extending from one end to the other end in the longitudinal direction of the vertical walls 33a and 33b, respectively. In this specification, “press-molding” refers to a product to be molded (for example, a blank 25 or an intermediate molded product 30) that is molded into a mold (for example, a first mold 20 and a second mold 20, which will be described later). This refers to the act from setting the mold 40) to closing the mold and opening the mold. In addition, "press-molding" means that an object to be molded is pressed (pressed) and molded.

[First press device]
The first press device 18 has a function of pressing the blank 25 to be molded and molding the intermediate molded product 30.

  As shown in FIG. 7, the first press device 18 includes a first mold 20 and a first moving device 25. As shown in FIGS. 6 and 7, the first mold 20 has an upper mold (die) 21, a lower mold (punch) 22, a first holder 23, and a second holder 24. ing. The upper mold 21 is arranged on the upper side, and the lower mold 22 is arranged on the lower side.

  The upper mold 21 and the lower mold 22 are long as shown in FIG. When the upper mold 21 and the lower mold 22 are viewed from the direction in which the upper mold 21 and the lower mold 22 face each other, the lower mold 22 is curved and protrudes along the longitudinal direction. A groove is formed along the groove. Further, in the upper mold 21, when viewed from the short direction of the upper mold 21, the width of the groove continuously increases from the bottom of the groove toward the opening side of the groove (from the upper side to the lower side). . When viewed from the short direction of the lower mold 22, the width of the protruding portion of the lower mold 22 decreases continuously from the lower side toward the upper side. The shape of the lower mold 22 is set to fit the shape of the groove of the upper mold 21 when the mold is closed.

  As shown in FIG. 7, when the lower mold 22 is viewed from the longitudinal direction, step portions 22a are formed on both side surfaces of the lower mold 22, respectively. In addition, step portions 21a and 21a 'are formed on both side surfaces of the groove of the upper die 21 along the step portions 22a, respectively. In addition, the inclination angle of the portion below the step portion 21a on the side surface where the step portion 21a is formed with respect to the vertical direction (the direction in which the upper mold 21 and the lower mold 22 face each other) is θ1.

  The first holder 23 and the second holder 24 are elongated along the upper mold 21 and the lower mold 22. The first holder 23 and the second holder 24 are arranged on both sides of the lower mold 22 in the lateral direction, as shown in FIGS. 6 and 7. The first holder 23 and the second holder 24 are urged upward by springs 26 and 27, as shown in FIG.

  The first moving device 25 moves the upper mold 21 toward the lower mold 22. That is, the first moving device moves the upper mold 21 relative to the lower mold 22.

  When the first moving device moves the upper mold 21 toward the lower mold 22 in a state where the blank 25 is arranged at a position where the gap between the upper mold 21 and the lower mold 22 is determined, as shown in FIG. The blank 25 is pressed to form the intermediate molded product 30 in a state where the both ends of the blank 25 in the short direction are sandwiched between the first holder 23 and the second holder 24 and the upper die 21 respectively. It has become. Then, the blank 25 is pressed by the step portions 22a (22a ') and the step portions 21a (21a') along with the formation of the intermediate molded product 30, so that the vertical walls 33a and 33b move vertically from the position of the top plate 2. Step portions 11a and 11a 'having a protrusion width a1 (mm) are formed at portions separated by at least 40% of the height of the walls 33a and 33b (see FIG. 4). In addition, since the shape of the groove of the upper mold 21 and the shape of the protruding portion of the lower mold 22 are as described above, the step portions 21a and 21a 'are located on the top plate 2 side when viewed from the longitudinal direction of the top plate 2. The openings are inclined so that the distance between them facing each other becomes larger (the facing width is increased) on the opening side. From another viewpoint, the step portions 21a and 21a 'are inclined so that the distance between the steps 21a and 21a' is larger on the opening side than on the top plate 2 side.

  As described above, the first press device 18 has been described. From another viewpoint, the first press device 18 is as follows. That is, the upper die 21 (an example of a first die) has a long bottom surface (first bottom surface) and side surfaces (first side surfaces) facing each other with one end connected to both ends of the bottom surface in the short direction. And a long groove (an example of a first groove) configured to include. The side surface (first side surface) is curved when viewed from the mold closing direction (the direction in which the upper die 21 and the lower die 22 face each other) and has a depth of 40 from the bottom surface (first bottom surface) to the groove (first groove). %, The step portions 11a and 11a '(first step portions) having a width of 20% or less of the width in the lateral direction of the bottom surface (an example of the first bottom surface) are located in the longitudinal direction of the side surface (first side surface). It is a curved surface (an example of a first curved surface) formed over it. The lower mold 22 (an example of a first punch) is adapted to fit into the groove (first groove) when the mold is closed. That is, the inclination angle of the portion of the lower die 22 below the step 22a with respect to the vertical direction (the direction in which the upper die 21 and the lower die 22 face each other) is θ1.

[Second press device]
The second pressing device 19 presses the intermediate molded product 30 to be molded, and a portion on the other end side (concave ridge line portion 34a side) of the step portion 11a formed on the vertical wall 33a of the intermediate molded product 30. It has a function of moving 33a1 (see FIGS. 3, 4 and 5) to the side (opposite side) where the vertical walls 33a and 33b face each other (opposite side) (the direction of arrow A in the figure).

  As shown in FIG. 9, the second press device 19 includes a second mold 40 and a second moving device 45. As shown in FIGS. 8 and 9, the second mold 40 has an upper mold 41, a lower mold 43, and a holder 42. The upper mold 41 is arranged on the upper side, and the lower mold 43 is arranged on the lower side. The lower die 43 is urged by a spring 46 from below. Then, the second pressing device 19 moves the upper die 41 to the lower die 43 side by the second moving device 45 in a state where the intermediate molded product 30 is fitted in the lower die 43, and the two The angles of the flanges 35a and 35b are changed.

  Further, as shown in FIG. 9, when the lower mold 43 is viewed from the longitudinal direction, step portions 43a are formed on both side surfaces of the lower mold 43, respectively. Further, on both side surfaces (curved surfaces) of the groove of the upper die 41, a step portion 41a (an example of a second step portion) is formed along the step portion 43a. The shape of the step portion 43a (41a) (the width in the short direction of the lower die 43) is equivalent to the shape of the step portion 22a (21a) of the first press device 18. Further, the step portion 43a (41a) is formed at a position corresponding to the step portion 22a (22a ') (a position where the step portions 11a and 11a' of the intermediate molded product 30 overlap). As shown in FIG. 9, when viewed from the longitudinal direction of the upper die 41, the width of the upper die 41 increases from the bottom of the groove toward the opening side of the groove (from the upper side to the lower side). It is continuously widening. When viewed from the longitudinal direction of the lower mold 43, the width of the protruding portion of the lower mold 43 decreases continuously from the lower side toward the upper side. The shape of the lower mold 43 is set to fit the shape of the groove of the upper mold 41 when the mold is closed.

  When the second moving device 45 moves the upper mold 41 toward the lower mold 43 in a state where the intermediate molded article 30 is fitted in the lower mold 43, the intermediate molded article 30 is pressed and the roof member 1 is molded. It has become. With the formation of the intermediate molded product 30, the portion 33a1 of the vertical wall 33a on the other end side of the stepped portion 36a is moved to the opposite side (outside) to the side (opposite side) where the vertical walls 33a and 33b face each other. It has become. For this reason, the inclination angle θ2 of the portion of the lower die 43 below the stepped portion 43a with respect to the vertical direction (the direction in which the upper die 21 and the lower die 22 face each other) is larger than the inclination angle θ1. Since the shape of the groove of the upper die 41 and the shape of the protruding portion of the lower die 43 are as described above, the step portions 43a and 41a are formed on the top plate 2 side when viewed from the short direction of the top plate 2. The openings are inclined so that the distance between them facing each other becomes larger (the facing width is increased) on the opening side. From another viewpoint, the step portions 41a and 41a 'are inclined so that the distance between the steps 41a and 41a' is larger on the opening side than on the top plate 2 side.

  As described above, the second press device 19 has been described. From a different viewpoint, the second press device 19 is as follows. That is, the upper mold 41 (an example of the second die) has a bottom surface (an example of the second bottom) of the same shape as the bottom surface (an example of the first bottom surface) of the upper mold 21 of the first press device 18 when viewed from the mold closing direction. One example) and one end is connected to both ends in the short direction of the second bottom surface, and a long groove (an example of the second groove) including side surfaces (an example of the second side surface) facing each other is formed. Have been. The second side surface (at least one of them is referred to as a second curved surface) is curved when viewed from the mold closing direction (the direction in which the upper mold 41 and the lower mold 43 face each other) and corresponds to the first step portion. The second curved surface is formed with a second step at a position where the second step is formed. Further, the angle θ2 at which the other end of the second curved surface relative to the second step portion is inclined with respect to the mold closing direction is such that the portion of the first curved surface closer to the other end of the first curved portion relative to the mold closing direction is closed. It is larger than the angle θ1 inclined to the direction. The lower mold 43 (second punch) fits into the shape of the groove (second groove) when the mold is closed. That is, the shape of the lower die 43 (an example of the second punch) is a shape that fits into the groove (second groove) when the die is closed.

  The above is the description of the configuration of the press device 17 of the present embodiment.

<Roof member manufacturing method>
Next, a method for manufacturing the roof member 1 of the present embodiment will be described with reference to the drawings. The method for manufacturing the roof member 1 according to the present embodiment is performed using a press device 17. Further, the method for manufacturing the roof member 1 according to the present embodiment includes a step (first step) performed by the first press device 18 and a step (second step) performed by the second press device 19.

[First step]
In the first step, a blank 25 is arranged in a gap between the upper mold 21 and the lower mold 22. Next, when the operator operates the first press device 18, the upper die 21 is moved to the lower die 22 side by the first moving device, and the blank 25 is press-formed by drawing. That is, in the first step, the blank 25 to be molded is pressed using the upper mold 21 and the lower mold 22. As a result, the intermediate molded product 30 is formed from the blank 25. Then, the intermediate molded product 30 is removed from the first mold 20, and the first step is completed.

[Second step]
Next, the intermediate molded product 30 is fitted into the lower die 43 of the second die 40 of the second press device 19. Then, when the operator operates the second press device 19, the upper die 41 is moved to the lower die 43 side by the second moving device, and the intermediate molded product 30 is pressed. That is, in the second step, the blank 25 formed in the first step is pressed using the upper mold 21 and the lower mold 22. As a result, the roof member 1 is molded from the intermediate molded product 30. Then, the roof member 1 is removed from the second mold 40, and the second step is completed. Accordingly, the method of manufacturing the roof member 1 according to the present embodiment ends.

  The above is the description of the method for manufacturing the roof member 1 of the present embodiment.

<Action>
Next, the operation of the present embodiment will be described in comparison with a later-described comparative embodiment (not shown). In the description of the comparative embodiment, when the same components and the like as those used in the present embodiment are used, the symbols of the components and the like are used as they are even when not shown. The roof member 1 (not shown) of the comparative example corresponds to a comparative example 5 in a comparative example described later (see FIG. 9).

  In the case of the comparative embodiment, the blank 25 is pressed by the second pressing device 19 to form a roof member. Except for this point, the comparative embodiment is the same as the present embodiment.

  According to the evaluation result of the comparative example (Comparative Example 5), as shown in the table of FIG. 14, the bending at the front end is 4.38 (mm), the bending at the rear end is 5.85 (mm), and the average bending is Was 5.12 (mm).

  Here, the evaluation of the front end bending and the rear end bending is based on the roof member data created by the simulation based on the roof member manufacturing method of the comparative embodiment with respect to the design data and the roof member manufacturing method of the present embodiment. The data was compared with the data of the roof member 1 created by the simulation. Specifically, using a computer (not shown), the cross section of the central portion in the longitudinal direction of the top plate 2 is matched (best fit), and the measurement is performed on the center position of the front end (rear end) in the design data. The deviation amount in the width direction of the center position of the front end (rear end) of the obtained data is defined as a bend, and the average value of the front end bend value and the rear end bend value is defined as the average bend amount (see FIG. 10). ).

  On the other hand, according to the evaluation of the present embodiment (Example 9), as shown in the table of FIG. 14, the bending of the tip portion of the roof member 1 created by the simulation based on the manufacture of the roof member of the present embodiment. 5.02 (mm), the rear end bending was 4.34 (mm), and the average bending amount was 4.68 (mm). That is, in the present embodiment, it can be said that the occurrence of bending in the short direction of the top plate 2 due to springback is suppressed as compared with the comparative embodiment.

  As described above, in the present embodiment, the reason why the occurrence of bending as viewed from the top 2 is suppressed as compared with the comparative embodiment is presumed as follows. That is, in the case of the comparative embodiment, as described above, the blank 25 is pressed by the second pressing device 19 to form the roof member. The vertical wall 4a of the roof member has a curved surface that is convexly curved to the side opposite to the side facing the vertical wall 4b when viewed from the top plate 2 side. The vertical wall 4b is inclined with respect to the vertical direction (the thickness direction of the top plate 2). Therefore, in the case of the comparative embodiment, when the roof member is press-molded and removed from the second mold 40, a compressive stress acts on the outer surface of the vertical wall 4a in the longitudinal direction of the top plate 2. In particular, a portion 4a1 (see FIGS. 1 and 2) of the vertical wall 4a closer to the concave ridge 5a than the step 11a is a portion 4a2 of the vertical wall 4a closer to the convex ridge 3a than the step 11a (see FIGS. 1 and 2). 2) (see FIG. 2). Therefore, the outer surface of the portion 4a1 has a larger compressive stress acting in the longitudinal direction of the top plate 2 than the outer surface of the portion 4a2. From the above results, it is inferred that the roof member of the comparative example was bent when viewed from the top plate 2 side. On the other hand, in the case of the present embodiment, in the second step, the portion 33a1 on the other end side (concave ridge portion 34a side) of the step portion 11a formed on the vertical wall 33a of the intermediate molded product 30 (FIG. 3, FIG. 4 and 5) are moved to the side (opposite side) where the vertical walls 33a and 33b face each other (opposite side) (the direction of the arrow A in the figure) to become the portion 4a1 (see FIG. 5). Therefore, the present embodiment is in a state where the compressive stress applied in the longitudinal direction of the portion 4a1 is reduced as compared with the comparative embodiment. As a result, in the present embodiment, the target shape (bending allowable value) is more likely to occur after the outer surface of the portion 4a1 bends due to the action of compressive stress as compared with the comparative embodiment.

  Therefore, according to the present embodiment, in the second step, the vertical wall 33a of the intermediate molded product 30 is placed on the opposite side (opposite side) where the vertical walls 33a and 33b face each other (opposite side) (the direction of arrow A in the drawing). Compared with the case where the top plate 2 is not moved, the generation of the bending of the top plate 2 in the lateral direction due to the springback is suppressed. In the case of the present embodiment, a spring 33 is used to move the portion 33a1 of the vertical wall 4a away from the protruding ridge line portion 3a in the second step to the side opposite to the side (opposite side) where the vertical walls 33a and 33b face each other. The effect of suppressing the occurrence of bending of the top plate 2 in the short direction due to the back becomes more remarkable.

  The above is the description of the operation of the present embodiment.

<< 2nd Embodiment >>
Next, a second embodiment will be described. First, the configuration of the roof member 1A (see FIGS. 11 and 12) of the present embodiment will be described. Next, the configuration of the press device (not shown) of the present embodiment will be described. Next, a method for manufacturing the roof member 1A of the present embodiment will be described. Next, the operation of the present embodiment will be described. Note that, in the following description, portions of the present embodiment that are different from the first embodiment will be described.

<Configuration of roof member>
First, the configuration of the roof member 1A of the present embodiment will be described with reference to the drawings. Here, the roof member 1A is an example of a press-formed product and a specific press-formed product.

  The roof member 1A of this embodiment (see FIGS. 11 and 12) does not include the flanges 6a and 6b (FIGS. 1 and 2). Except for this point, the roof member 1A of the present embodiment has the same configuration as the roof member 1 of the first embodiment.

<Configuration of press device>
Next, the press device of the present embodiment will be described. The press device of the present embodiment is for manufacturing the roof member 1A.

  The first press device of the present embodiment is different from the first press device 18 of the first embodiment in that it does not include the holders 23 and 24 (FIGS. 6 and 7). Except for this point, the first press device of the present embodiment has the same configuration as the press device 17 of the first embodiment. The intermediate molded product formed by the first pressing device is the same as that of the first embodiment except that the intermediate molded product 30 does not include the two flanges 35a and 35b (FIGS. 3 and 4) of the first embodiment. Has the same configuration as that of the intermediate molded product 30. That is, in the intermediate molded product of the present embodiment, the cross section viewed from the longitudinal direction of the top plate 2 is a groove-shaped member.

<Roof member manufacturing method>
Next, a method for manufacturing the roof member 1A of the present embodiment will be described. The method for manufacturing the roof member 1A of the present embodiment is the same as that of the first embodiment except that the first press device of the present embodiment is used instead of the first press device 18 of the first embodiment. In the case of the present embodiment, in the first step, the blank 25 is press-formed by bending to form an intermediate molded product, and in the second step, the intermediate molded product is press-formed by bending to form the roof member 1A. Molded.

<Action>
The operation of the present embodiment is the same as the operation of the first embodiment (see the table in FIG. 15 described later).

  The above is the description of the second embodiment.

<< Example >>
Next, simulations of Examples and Comparative Examples will be described with reference to the drawings. In the following description, when the same reference numerals as those used in the present embodiment and the comparative embodiment are used, the same reference numerals are used as they are.

  In this simulation, as shown in the table of FIG. 14, the roof member 1 (Examples 1 to 19) created by the simulation based on the roof member manufacturing method of the first embodiment and the roof member of the comparative embodiment described above. With respect to the roof members (Comparative Examples 1 to 6) created by simulation based on the manufacturing method, the bending at the one end 1a and the other end 1b and the average bending amount were evaluated. In this simulation, as shown in the table of FIG. 15, the roof member 1 (Examples 20 to 37) created by the simulation based on the roof member manufacturing method of the second embodiment and the roof of the comparative embodiment described above. The bending at the one end 1a and the other end 1b and the average bending amount were evaluated for the roof members (Comparative Examples 7 to 12) created by the simulation based on the member manufacturing method.

[Description of Table in FIG. 14]
The table of FIG. 14 describes simulation conditions and evaluation results for Examples 1 to 19 (hat shape) and Comparative Examples 1 to 6 (hat shape). Here, the table of FIG. 14 will be described. The plate thickness is the thickness of the blank 25 used in the simulation. The strength is the tensile strength of the blank 25 used for the simulation. The outer vertical wall change start point (%) is a position in the height direction of the other end (the end connected to the concave ridge line portion 34a) in the portion 33a1 with the convex portion 11a2 of the intermediate molded product 30 as a reference (0%). The start position of the portion 33a1 when 100% is set is shown. For example, FIG. 13 shows a case where the outer vertical wall change start point is set to 50%. When the outer vertical wall change start point (%) is "-", it means that there is no change start point in the first place, that is, the portion 33a1 is not moved in the second step. The inside vertical wall change start point (%) is the other end of the portion 33b1 (see FIG. 13) below the convex portion 11a'2 with the convex portion 11a'2 of the intermediate molded product 30 as a reference (0%). The start position of the portion 33b1 when the position in the height direction of the (end connected to the concave ridge line portion 34b) is 100% is shown. For example, FIG. 13 shows a case where the inside vertical wall change start point is set to 50%. When the inside vertical wall change start point (%) is "-", it means that there is no change start point in the first place, that is, the part 33b1 is not moved in the second step. Therefore, to mold the roof member 1 in FIG. 13, only the second press device (not shown) is different from the second press device 19 of the press device 17 of the first embodiment. Specifically, the second press device is configured such that at least a part of a portion of the second curved surface of the cross section of the second die projected on the cross section of the first die on the other end side with respect to the second stepped portion, The first curved surface is located outside the first step portion on the other end side of the first stepped portion. That is, the second press device presses the intermediate molded product 30 to be molded, and the other end side (the concave ridge line portion 34b side) of the stepped portion 11a 'formed on the vertical wall 33b of the intermediate molded product 30. Has a function of moving the portion 33b1 (see FIG. 13) to the side opposite to the side (opposite side) where the vertical walls 33a and 33b face each other (the direction of arrow A in the figure).

  The roof members of Comparative Examples 1 to 4 are examples of the above-described comparative embodiment. The roof members of Examples 1 to 19 are examples of the roof member 1 of the first embodiment.

[Evaluation results and considerations]
From the table in FIG. 14, the roof member of the example has a smaller bend than the comparative example (the amount of bend is smaller than that of the comparative example) under the same thickness and strength conditions as compared with the roof member of the comparative example. ). For example, when Example 1 and Comparative Example 1 are compared, and Example 3 and Comparative Example 2 are compared, in each of the examples, the bending is smaller than the comparative example (the bending amount is smaller). That is, it is considered that these examples exhibit the operation and effect of the first embodiment.

  Further, comparing Example 14 with Comparative Example 5, Example 14 has a smaller bend (a smaller amount of bend) than Comparative Example 5. In Example 14, the portion 33b1 of the vertical wall 4b, which is different from the first embodiment and the second embodiment, below the step portion 11a 'is formed in a direction opposite to the direction in which the vertical wall 4a faces the vertical walls 33a, 33b (see FIG. (In the direction opposite to the direction of arrow A). The vertical wall 4b has a curved surface that is concavely curved on the side opposite to the side facing the vertical wall 4b when viewed from the top plate 2. In the case of the roof member of Example 14, the outer surface of the moved portion 33b1 bends due to the tensile stress acting on the outer surface of the moved portion 33b1 as compared with Comparative Example 5 in the case of the roof member of Examples 5 and 9 as compared with Comparative Example 5. It is considered that the target shape (bending tolerance) is likely to occur later.

[Description of Table in FIG. 15]
The table of FIG. 14 describes the simulation conditions and evaluation results for Examples 20 to 37 (groove shapes) and Comparative Examples 7 to 12 (groove shapes).

  The roof members of Comparative Examples 7 to 12 are examples of the above-described comparative embodiment. The roof members of Examples 20 to 37 are examples of the roof member 1 of the first embodiment.

[Evaluation results and considerations]
From the table of FIG. 15, the roof member of the example has a smaller bend than the comparative example (the amount of bend is smaller than that of the comparative example) under the same thickness and strength conditions as compared with the roof member of the comparative example. ). For example, when Example 20 and Comparative Example 7 are compared, and Example 21 and Comparative Example 8 are compared, in each of the examples, the bending is smaller (the amount of bending) is smaller than the comparative example. That is, it is considered that these examples exhibit the operation and effect of the second embodiment.

  Also, comparing Example 31 with Comparative Example 11, Example 31 has a smaller bend (a smaller amount of bend) than Comparative Example 11. In Example 31, the portion 33b1 of the vertical wall 4b different from the first embodiment and the second embodiment, which is lower than the stepped portion 11a ', is opposed to the direction facing the vertical walls 33a, 33b (see FIG. 13). (In the direction opposite to the direction of arrow A). The vertical wall 4b has a curved surface that is concavely curved on the side opposite to the side facing the vertical wall 4b when viewed from the top plate 2. Then, in the case of the roof member of Example 31, it is considered that, compared to Comparative Example 11, the outer shape of the moved portion 33b1 tends to have a target shape (bending allowable value) after the outer surface of the moved portion 33b1 bends due to a tensile stress. .

  The above is the description of the embodiment.

  As described above, the present invention has been described with respect to the specific embodiment. However, the technical scope of the present invention includes embodiments other than the above-described embodiment. For example, the technical scope of the present invention includes the following embodiments.

  In each of the embodiments and examples, an example of the press-formed product has been described as a roof member. However, if the intermediate molded product is manufactured including a process of pressing the intermediate molded product to move a portion on the other end side of the curved wall to the opposite side to the opposite side, the pressed molded product is a roof member. Other automotive parts may be used. Also, if the intermediate molded product includes a step of pressing the intermediate molded product to move a portion on the other end side of the curved wall to the opposite side to the opposite side, it is a component other than a component for an automobile. Is also good.

  In each embodiment and example, the vertical walls 4a and 4b have been described as being curved walls. However, one of the vertical walls 4a and 4b is a curved wall, and the step of pressing the intermediate molded product and moving the portion of the curved wall on the other end side of the stepped portion to the opposite side to the opposite side. The other vertical walls 4a and 4b do not have to be curved walls if they are formed by including them. For example, the other vertical walls 4a and 4b may be linear walls along the longitudinal direction.

1 Roof member (an example of a press-formed product)
2 Top plates 3a, 3b Convex ridges 4a, 4b Vertical wall (an example of a curved wall)
17 Pressing device 18 First pressing device 19 Second pressing device 25 Blank 30 Intermediate molded product stepped portion 36a, 36a '

Claims (6)

A long top plate, ridge portions at both ends in the short direction of the top plate, and one end facing each other in a state where one end is connected to the ridge portion, at least one of which is curved as viewed from above the top plate. A method of manufacturing a press-formed product including a pair of vertical walls and a curved wall that is,
Pressing a blank, the top plate, the ridge portions at both ends, and a curved wall which is opposed to each other in a state where one end is connected to the ridge portion, and at least one of which is curved as viewed from above the top plate. A vertical section formed on the curved wall along the longitudinal direction of the top plate, wherein the vertical wall is configured to include a pair of vertical walls, A first step of molding a molded article;
A second step of pressing the intermediate molded product and moving a portion of the curved wall closer to the other end than the stepped portion to the opposite side to the opposite side;
And a method for producing a press-formed product. In the first step, the step is formed in a portion of the curved wall separated from the top plate by 40% or more of a height from the top plate to a lower end of the curved wall with reference to a position of the top plate.
A method for producing a press-formed product according to claim 1. In the first step, the step portion is formed such that a protrusion width of the step portion is 20% or less of a width in a short direction of the top plate.
A method for producing a press-formed product according to claim 2. A long top plate, ridge portions at both ends in the short direction of the top plate, and one end facing each other in a state where one end is connected to the ridge portion, at least one of which is curved when viewed from above the top plate. A press device for a press-formed product including a pair of vertical walls that are curved walls,
Pressing a blank, the top plate, the ridge portions at both ends, and a curved wall which is opposed to each other in a state where one end is connected to the ridge portion, and at least one of which is curved as viewed from above the top plate. A vertical section formed on the curved wall along the longitudinal direction of the top plate, wherein the vertical wall is configured to include a pair of vertical walls , A first press device for forming a molded product,
A second pressing device that presses the intermediate molded product, and moves a portion of the curved wall closer to the other end than the stepped portion to the opposite side to the opposite side,
Press machine for press-formed products provided with. A first press device for pressing a blank with a first die and a first punch to form an intermediate molded product, and a second press device for pressing the intermediate molded product with a second die and a second punch. A press device,
The first die has an elongated first bottom surface and an elongated first bottom surface including one end connected to a short-side end of the first bottom surface and opposing first side surfaces. A groove is formed,
At least one of the first side surfaces is curved as viewed from a mold closing direction, and a first curved surface formed with a first step portion extending in a longitudinal direction of the first side surface to increase an opposing width of the first side surface. And
The shape of the first punch is a shape that fits with the shape of the first groove when the mold is closed.
A first pressing device;
The second die has an elongated second bottom surface, and an elongated second bottom surface including one end connected to the short-side end of the second bottom surface and opposing second side surfaces. A groove is formed,
At least one of the second side surfaces is curved as viewed from the mold closing direction, and is a second curved surface having a second step portion formed at a position corresponding to the first step portion,
The angle at which the portion of the second curved surface on the other end side of the second step portion is inclined with respect to the mold closing direction is such that the portion of the first curved surface on the other end side of the first step portion is more inclined. Larger than the angle of inclination with respect to the mold closing direction,
The shape of the second punch is a shape that fits with the shape of the second groove when the mold is closed.
A second pressing device;
Press device equipped with. A first press device for pressing a blank with a first die and a first punch to form an intermediate molded product, and a second press device for pressing the intermediate molded product with a second die and a second punch. A press device,
The first die has an elongated first bottom surface and an elongated first bottom surface including one end connected to a short-side end of the first bottom surface and opposing first side surfaces. A groove is formed,
At least one of the first side surfaces is curved as viewed from a mold closing direction, and a first curved surface formed with a first step portion extending in a longitudinal direction of the first side surface to increase an opposing width of the first side surface. And
The shape of the first punch is a shape that fits with the shape of the first groove when the mold is closed.
A first pressing device;
The second die has an elongated second bottom surface, and an elongated second bottom surface including one end connected to the short-side end of the second bottom surface and opposing second side surfaces. A groove is formed,
At least one of the second side surfaces is curved as viewed from the mold closing direction, and is a second curved surface having a second step portion formed at a position corresponding to the first step portion,
At least a part of a portion of the second curved surface of the cross section of the second die projected onto the cross section of the first die on the other end side of the second curved portion is the first stepped portion of the first curved surface. Outside than the other end,
The shape of the second punch is a shape that fits into the shape of the second groove when the mold is closed.
A second pressing device;
Press device equipped with.