JP2011016161A - Method of manufacturing closed cross-sectional member made of metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of formation of a closed cross-sectional member in a method of manufacturing the closed cross-sectional member made of metal, in which the closed cross-sectional member is manufactured by press-forming the projecting part of a planar workpiece.SOLUTION: The method of manufacturing the closed cross-sectional member which is formed from the planar workpiece W1 made of metal, includes: a first press-forming step where the planar workpiece is press-formed into a projective shape and also a projecting part W2a projecting in the opposite direction to the projective top surface part is formed; a second press-forming step where a closed cross section is made by displacing projective side face parts on both sides to inward side respectively by press-forming the projecting part in the direction opposite to the projecting direction; and a tab part forming step where tab parts W2f are formed integrally in the end parts in the longitudinal direction of the planar workpiece in the projecting part of the planar workpiece. The second press-forming step is performed by positioning the tab parts which are formed in the tab forming stage to a press-forming die 60 for press-forming the projecting part in the direction opposite to its projecting direction.

Description

  The present invention relates to a method for manufacturing a metal closed cross-section member that manufactures a closed cross-section member formed in a closed cross-section shape from a metal plate-shaped material (plate-shaped workpiece).

  As is well known, body members such as pillar members that form part of the basic structure of a vehicle body in a vehicle such as an automobile, front and rear side frames, and a dash cross member that is located in the lower front portion of a dash panel include: From the viewpoint of ensuring strength and rigidity and improving safety, high strength and high rigidity are required, and weight reduction is required for improving fuel efficiency.

  In order to meet these demands, the vehicle body member as described above is often configured as a metal closed cross-section member. As a method of manufacturing such a metal closed cross-section member, for example, a metal plate-like workpiece such as a steel plate is formed into a cross-sectional hat shape by integrally molding flange portions projecting outward at both ends of a U-shaped cross section by pressing. In general, a method of manufacturing a closed cross-section member by overlapping the flange portions of two plate-like workpieces formed in a cross-sectional hat shape to form a closed cross-section shape and then welding the flange portions is known. Yes.

  Further, for example, in Patent Document 1, a triangular tube as a closed cross-section member is manufactured, and a first bending step of bending the vicinity of both end portions of a steel plate cut into a predetermined shape with a predetermined curvature, and the first A second bending step in which the central portion of the steel plate bent at both ends in the bending step is pushed and bent at a predetermined curvature, and a lower die in which a plurality of plates having notches having substantially the same shape as the forming cross section are arranged in parallel A constraining forming step of pressing the central portion of the steel sheet formed in the second bending step so as to follow and constraining the curved portions in the vicinity of both ends of the steel plate to be spread outward with an upper mold, A method of manufacturing a triangular tube having a welding step of welding the butted portions at both ends without unloading after the forming step is disclosed.

JP 2000-51932 A

  By the way, when manufacturing a vehicle body member configured as a metal closed cross-section member used in a vehicle such as an automobile by overlapping the flange portions of two plate-like workpieces formed in a cross-sectional hat shape, a closed cross-section Weight reduction will be hindered by the flange part used only for manufacturing a member.

  On the other hand, the method for manufacturing a triangular tube described in Patent Document 1 does not form a flange portion used only for manufacturing a closed cross-section member, and thus can be reduced in weight, but is used for a vehicle such as an automobile. Since the vehicle body member has a complicated shape and the cross-sectional shape can change in a complicated manner in the longitudinal direction, a plurality of plates having different shapes of the notches must be prepared in order to produce the lower mold. It can be difficult to apply to a vehicle body member used in a vehicle such as an automobile.

  For this, a first press molding step of pressing the plate-like workpiece into a convex shape, and forming a convex portion protruding in the opposite direction on the convex top surface portion press-formed into the convex shape, and this By pressing the convex part in the direction opposite to the protruding direction, the convex side surface parts on both sides of the convex top surface part formed in the first press molding process are displaced to the inner side of the plate-like workpiece and closed. A method of manufacturing a closed cross-section member from a plate-like workpiece by the second press forming step of making a cross section is conceivable.

  According to this method, it is not necessary to prepare a plurality of plates having different shapes of the flange portion used only for manufacturing the closed cross-section member and the notch portion for producing the lower mold, and the cross-sectional shape of the closed cross-section member. Even in the case where the length changes in the longitudinal direction, it is possible to manufacture the closed cross-section member from the plate-like workpiece relatively easily.

  However, when manufacturing a closed cross-section member from a plate-like workpiece by such a method, the convex portion of the plate-like workpiece is press-molded, and the convex side portions on both sides are displaced inward to make a closed cross-section. For example, due to a shift in the positional relationship with the press mold that press-molds the convex portion of the plate-like workpiece, the end portions of the convex side portions on both sides may not be close in a regular positional relationship, An improvement for improving the molding accuracy of the closed cross-section member is desired.

  Accordingly, the present invention has been made in view of the above technical problem, and in a method for manufacturing a metal closed cross-section member that manufactures a closed cross-section member by press-molding a convex portion of a plate-like workpiece, the closed cross-section member is provided. The object is to improve the forming accuracy of the member.

  For this reason, the manufacturing method of the metal closed cross-section member according to claim 1 of the present application presses the metal plate-like workpiece into a convex shape, and at the convex top surface portion formed into the convex shape of the plate-like workpiece. A first press molding step of molding a convex portion projecting in a direction opposite to the convex projecting direction of the plate-like workpiece; and the convex portion molded in the first press molding step is reverse to the projecting direction. A second press molding step of crushing the convex portion by press molding in a direction and displacing the convex side surface portions on both sides of the convex top surface portion inwardly to make a closed cross section. A method of manufacturing a metal closed cross-section member that manufactures a closed cross-section member formed in a closed cross-section shape from the plate-shaped workpiece, and before the second press molding step, at the convex portion of the plate-shaped workpiece. A tab portion is integrated with the longitudinal end portion of the plate-like workpiece. A tab portion forming step, wherein the second press molding step is formed in the tab portion forming step with respect to a press mold for press molding the convex portion in a direction opposite to the protruding direction. It is characterized by performing the positioning.

  The invention according to claim 2 of the present application is the invention according to claim 1, wherein the press mold includes a die that holds the plate-like workpiece, and the convex in a state where the plate-like workpiece is held by the die. A core mold that press-molds the part in the direction opposite to the protruding direction thereof, and the second press-molding step is performed by positioning the tab part with respect to the die. .

  Further, the invention according to claim 3 of the present application is the invention according to claim 1 or 2, wherein the tab portion is provided with a positioning hole and a positioning pin is provided in the press mold, and the second press molding step. Is characterized in that the tab portion is positioned with respect to the press mold by fitting the positioning hole to the positioning pin.

  Still further, the invention according to claim 4 of the present application is the invention according to any one of claims 1 to 3, wherein the plate-like workpiece is interposed between the first press molding step and the second press molding step. The method further comprises a bending step of bending an end portion of the convex side surface portion opposite to the convex top surface portion side toward the inward side of the plate-like workpiece.

  Still further, the invention according to claim 5 of the present application is the invention according to any one of claims 1 to 4, wherein the convex shape in which the plate-like workpiece is closed in cross section after the second press molding step. It is further characterized by further comprising a final pressing step of pressing and pressing the end portions of the side surface portions against the surface portion opposite to the surface portion that presses the convex portion of the core mold. is there.

  Furthermore, the invention according to claim 6 of the present application is the invention according to any one of claims 1 to 5, wherein the convex shape in which the plate-like workpiece is closed in cross section after the second press molding step. The method further includes a welding step of welding the end portions of the side surface portions.

  According to the manufacturing method of the metal closed cross-section member according to claim 1 of the present application, the first press molding step of pressing the plate-like workpiece into a convex shape and forming the convex portion on the convex top surface portion, and the convex portion A second press molding step of crushing the convex portion by press molding and displacing the convex side surface portions on both sides inward to make a closed cross-section, and the length of the plate-like workpiece in the convex portion A tab portion forming step of integrally forming a tab portion at an end portion in the direction, and the second press molding step includes a tab portion with respect to a press mold that presses the convex portion in a direction opposite to the protruding direction. By performing positioning, the second press molding is performed in a state where the plate-shaped workpiece and the press-molding die are held in a predetermined positional relationship, and the end portions of the convex side portions on both sides of the plate-shaped workpiece. Can always be in close proximity with the mold Which molding device and molding process without complicating the metal closed-section member can be accurately produced in a relatively simple manner.

  Further, according to the invention according to claim 2 of the present application, the press mold includes a die for holding the plate-like workpiece, and the convex portion is press-molded in a direction opposite to the protruding direction while holding the plate-like workpiece on the die. The second press molding step can be positioned with respect to the die fixed in the second press molding step by positioning the tab portion with respect to the die. The effect can be obtained effectively.

  Further, according to the invention of claim 3 of the present application, the tab portion is provided with the positioning hole and the press mold is provided with the positioning pin. In the second press molding step, the positioning hole is fitted to the positioning pin. By matching, by positioning the tab portion with respect to the press mold, positioning can be performed by a relatively simple and reliable method, and the above-described effects can be obtained with certainty.

  Still further, according to the invention according to claim 4 of the present application, the convex side surface side of the convex side surface portion of the plate-like workpiece is opposite to the convex side surface portion between the first press molding step and the second press molding step. By further comprising a bending process for bending the end part to the inner side of the plate-like workpiece, when the convex side parts on both sides are displaced inward, the inner side of the convex side part The metal closed cross-section member can be manufactured more accurately with less displacement.

  Still further, according to the invention according to claim 5 of the present application, after the second press molding step, the end portions of the convex side surface portions of the plate-like workpiece having the closed cross section are replaced with the core type convex portions. By providing a pressing process that presses against the surface part opposite to the surface part to be pressed and press-molding, it is possible to obtain high forming accuracy by a relatively simple method for the surface opposite to the pressing part. It is possible.

  Still further, according to the invention according to claim 6 of the present application, the method further includes a welding step of welding the end portions of the convex side portions of the plate-like workpiece having a closed cross section after the second press forming step. Accordingly, the bonding strength of the closed cross-section member can be increased, and a stronger closed cross-section member can be manufactured.

It is a side view showing typically the body structure of a car provided with the metal closed section member concerning this embodiment. It is a perspective view showing the front side frame as a metal closed section member concerning this embodiment. FIG. 3 is a cross-sectional view of the front side frame taken along lines Y3a-Y3a and Y3b-Y3b in FIG. It is a figure which shows the plate-shaped workpiece | work for manufacturing a front side frame. It is a perspective view which shows the press-molding die of the 1st press-molding apparatus for press-molding a plate-shaped workpiece. FIG. 6 is a cross-sectional view of the press mold along the line Y6-Y6 in FIG. It is explanatory drawing for demonstrating the press molding process by a 1st press molding apparatus. It is a perspective view which shows the plate-shaped workpiece press-molded by the 1st press molding apparatus. It is sectional drawing of the plate-shaped workpiece along the Y9-Y9 line | wire in FIG. It is a perspective view which shows the principal part of the plate-shaped workpiece press-molded by the 1st press molding apparatus. It is sectional drawing which shows the bending mold of the bending apparatus for bending the edge part of the convex side part of a plate-shaped workpiece. It is explanatory drawing for demonstrating a bending process. It is explanatory drawing for demonstrating a bending process. It is a side view of the press mold of the 2nd press molding apparatus for press-molding the convex part of a plate-shaped workpiece. It is a longitudinal cross-sectional view of the press molding die of the 2nd press molding apparatus along the Y15-Y15 line | wire in FIG. FIG. 16 is a cross-sectional view of the press mold of the second press molding apparatus along the line Y16-Y16 in FIG. It is explanatory drawing for demonstrating the press molding process by a 2nd press molding apparatus, and is a longitudinal cross-sectional view of the said press mold which shows the state by which the convex part of the plate-shaped workpiece was press-molded. It is explanatory drawing for demonstrating the press molding process by a 2nd press molding apparatus, and is a cross-sectional view of the said press mold which shows the state by which the convex part of the plate-shaped workpiece was press-molded. It is explanatory drawing for demonstrating the press molding process by a 2nd press molding apparatus about the cross section corresponding to the cross section shown in FIG.3 (b) of a front side frame. It is a longitudinal cross-sectional view of the said press mold which shows the state by which a part of tab part of the plate-shaped workpiece was cut | disconnected and bent after the convex part of the plate-shaped workpiece was press-molded. It is explanatory drawing for demonstrating a final pressing molding process. It is a figure which shows the state by which the bracket was joined to the flange part of the front side frame. It is explanatory drawing for demonstrating another method of manufacturing the metal closed cross-section member which concerns on this embodiment, and shows the press molding die of the 2nd press molding apparatus for press-molding the convex part of a plate-shaped workpiece. ing. It is a figure which shows the state by which the convex part of the plate-shaped workpiece was press-molded by the 2nd press-molding apparatus provided with the press-molding die shown in FIG. It is explanatory drawing for demonstrating the method used in order to attach a tab part with another member. It is sectional drawing which shows the state in which the two closed cross-section members shown in FIG. 25 were attached. It is explanatory drawing for demonstrating another method used in order to attach a tab part with another member. It is sectional drawing which shows the state in which the two closed cross-section members shown in FIG. 27 were attached.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, terms that mean a specific direction such as “up”, “down”, “right”, “left” and other terms including those terms are used. In order to facilitate understanding of the referenced invention, the technical scope of the present invention is not limited by the meaning of these terms.

  FIG. 1 is a side view schematically showing a vehicle body structure of an automobile provided with a metal closed cross-section member according to the present embodiment. In the present embodiment, as a metal closed cross-section member that is manufactured by forming a metal plate-like workpiece into a closed cross-section, a front side frame 20 coupled to a side body 10 of an automobile as shown in FIG. 1 is taken as an example. Although described, the present invention is not limited to this, and may be applied to other vehicle body members formed in a closed cross-sectional shape such as the rear side frame 30 coupled to the side body 10, and is not limited to the vehicle body members. It is also possible to apply to other metal closed cross-section members formed in a closed cross-section.

  FIG. 2 is a perspective view showing a front side frame as a metal closed section member according to the present embodiment. 3 is a cross-sectional view of the front side frame taken along the lines Y3a-Y3a and Y3b-Y3b in FIG. 2, and FIG. 3A shows the front side along the line Y3a-Y3a in FIG. 3B is a cross-sectional view of the front side frame taken along line Y3b-Y3b in FIG.

  As shown in FIG. 2, the front side frame 20 as a metal closed section member according to the present embodiment is configured as a closed section member that extends in the longitudinal direction and is formed in a closed section shape, The lower surface portion 22, the right side surface portion 23, the left side surface portion 24, the first inclined side surface portion 25 that is inclined obliquely downward to the right from the upper surface portion 21 toward the right side surface portion 23, and the upper surface portion 21 toward the left side surface portion 24. A second inclined side surface portion 26 inclined obliquely downward to the left, a third inclined side surface portion 27 inclined obliquely upward and rightward from the lower surface portion 22 toward the right side surface portion 23, and from the lower surface portion 22 toward the left side surface portion 24. Thus, the fourth inclined side surface portion 28 inclined obliquely upward to the left is formed into an octagonal cross section having a hollow portion 29.

  As shown in FIG. 2, the front side frame 20 has an upper surface portion 21 and a lower surface portion 22 formed substantially in parallel along the longitudinal direction and substantially the same cross-sectional length in the short direction. The cross-sectional shape is changed in the longitudinal direction. In the cross section shown in FIG. 3A, the front side frame 20 includes a left side surface portion 24, a first inclined side surface portion 25, and a third inclined side surface portion 27, the left side surface portion 24 in the cross section shown in FIG. The right inclined surface portion 23, the second inclined side surface portion 26, and the fourth inclined surface are formed so as to have shorter cross-sectional lengths than the first inclined side surface portion 25 and the third inclined side surface portion 27. The side surface portion 28 is formed to have a cross-sectional length longer than the cross-sectional lengths of the right side surface portion 23, the second inclined side surface portion 26, and the fourth inclined side surface portion 28 in the cross section shown in FIG. ing. Further, the inclination angle of the third inclined side surface portion 27 with respect to the lower surface portion 22 and the inclination angle of the fourth inclined side surface portion 28 with respect to the lower surface portion 22 are each formed at a predetermined constant angle in the longitudinal direction.

  In the present embodiment, the front side frame 20 as a metal closed cross-section member is also provided with flanges that are bent downward in a direction substantially perpendicular to the lower surface portion 22 at both ends in the longitudinal direction, as shown in FIG. The part 22a is integrally formed.

  In this way, in order to join the flange portion 22a to another member by integrally forming the flange portion 22a extending in a substantially right angle direction at both ends in the longitudinal direction on the lower surface portion 22 of the front side frame 20. It is possible to use. When joining other members to both ends of the front side frame 20 in a direction perpendicular to the longitudinal direction, the flange portions 22a can be easily joined to other members by being along the other members.

Next, manufacture of the front side frame 20 as a metal closed cross-section member according to the present embodiment configured as described above will be described.
In this embodiment, when the front side frame 20 is manufactured, first, a rectangular metal plate material (plate work) formed in a substantially flat plate shape such as a steel plate is prepared, and this plate work W1. Is trimmed, and a tab portion used for positioning when the convex portion of the plate-like workpiece is press-molded as described later is formed. In the present embodiment, a part of the tab portion is also cut to form the flange portion 22a of the front side frame 20.

  FIG. 4 is a view showing a plate-like workpiece for manufacturing the front side frame. As shown in FIG. 4, the plate-like workpiece W1 is trimmed by the first trimming means (not shown) at the both ends in the longitudinal direction of the plate-like workpiece W1, and the portions located outside the trimming line L1 are trimmed. In both ends of the longitudinal direction, tab portions W2f extending in the longitudinal direction are formed at the center in the lateral direction. As will be described later, the trimming line L1 is set so that the tab portion W2f is formed continuously with the convex portion W2a of the convex top surface portion W2 when the plate-like workpiece W1 is press-formed in a convex shape. .

  After trimming the plate-like workpiece W1 so that the tab portions W2f are formed at both ends in the longitudinal direction of the plate-like workpiece W1, the plate-like workpiece W1 is press-molded into a convex shape, specifically, draw (drawing) molding. Then, it is formed into a predetermined shape corresponding to the shape of the front side frame 20.

  FIG. 5 is a perspective view showing a press forming die of a first press forming apparatus for press forming a plate-like workpiece, and FIG. 6 is a cross-sectional view of the press forming die along line Y6-Y6 in FIG. It is. In FIG. 5, the concave portion provided on the lower surface of the die of the press mold and the punch provided in the blank holder of the press mold are shown by solid lines, and FIG. 6 also shows a plate-like work held by the blank holder. ing.

  As shown in FIGS. 5 and 6, the first press molding apparatus for press-molding the plate-like workpiece W1 presses the plate-like workpiece W1 into a convex shape, and the convex shape of the plate-like workpiece W1. A die 45 and a punch 42 for forming a convex portion projecting in a direction opposite to the convex direction of the plate-like workpiece W1 on the convex top surface portion to be formed, A press forming die 40 having a punch 42 and a blank holder 41 that sandwiches a plate-like workpiece W1 with a die 45 is provided.

  The die 45 of the press mold 40 is provided with a recess 45b that is recessed in the lower surface 45a, and a molding space 45c for press-molding the plate-like workpiece W1 is formed in the recess 45b. The concave portion 45b provided in the die 45 is formed in a predetermined shape according to the shape of the front side frame 20, and as shown in FIG. 6, a bottom surface portion 45d formed in a substantially flat shape and a right diagonal from the bottom surface portion 45d. A first inclined wall portion 45e inclined downward, a right vertical wall portion 45f extending vertically downward from the first inclined wall portion 45e, and a second inclined wall portion 45i inclined obliquely downward to the left from the bottom surface portion 45d. And a left vertical wall 45j extending downward in the vertical direction from the second inclined wall 45i.

  Further, the bottom surface portion 45d of the concave portion 45b provided in the die 45 is provided with a convex portion 45m that protrudes in a circular arc shape from the bottom surface portion 45d toward the inner side of the molding space 45c. The convex portions 45m are provided continuously in the longitudinal direction, and are formed such that the radius of curvature of the convex portions 45m formed in an arc shape in a cross section decreases toward the tip at both ends in the longitudinal direction.

  The punch 42 of the press mold 40 has the outer peripheral surface portion 42 a fitted into the inner peripheral surface portion 41 a of the blank holder 41, is moved in the vertical direction by a punch moving mechanism (not shown), and is moved relative to the die 45. It is like that. The punch 42 is formed in a predetermined shape according to the shape of the front side frame 20 in order to press-mold the plate-like workpiece W1 with the die 45, and the head of the punch 42 is formed in a substantially flat shape. 42 d of upper surface parts, the 1st inclination wall part 42e which inclines to the right diagonally downward from the upper surface part 42d, and the right vertical wall part which extends in the perpendicular direction downward from the 1st inclination wall part 42e, and comprises a part of outer peripheral surface part 42a 42f, a second inclined wall portion 42i inclined obliquely downward to the left from the upper surface portion 42d, and a left vertical wall portion 42j extending vertically downward from the second inclined wall portion 42i and constituting a part of the outer peripheral surface portion 42a, It has.

  Further, the upper surface portion 42d of the head portion of the punch 42 is provided with a concave portion 42m that is recessed from the upper surface portion 42d in a circular arc shape in cross section. The concave portion 42m is also provided continuously in the longitudinal direction, and at both ends in the longitudinal direction, the radius of curvature of the concave portion 42m formed in a circular arc shape as it goes toward the tip is reduced.

  The blank holder 41 of the press mold 40 is for holding the plate-like workpiece W1 against the die 45, and is illustrated so as to sandwich the plate-like workpiece W1 with the die 45 from the state in which the plate-like workpiece W1 is held. The blank holder moving mechanism is not moved up and down.

  Further, the first press molding apparatus includes a first press molding apparatus control unit (not shown) that comprehensively controls the first press molding apparatus, and controls the first press molding apparatus. The unit controls various operations such as a moving mechanism of the punch 42 and the blank holder 41. Note that the first press molding apparatus control unit, and the second press molding apparatus control unit and the bending molding apparatus control unit, which will be described later, include, for example, a microcomputer as a main part.

  In the first press molding apparatus including the press mold 40 configured as described above, the punch 42 is placed in the molding space 45c of the die 45 in a state where the plate-like workpiece W1 is sandwiched between the blank holder 41 and the die 45. The plate-like workpiece W1 is press-molded into a predetermined shape in accordance with the shape of the front side frame 20 by moving the plate to the plate-like workpiece W1.

  When press-molding the plate-like workpiece W1 using the first press-molding apparatus, as shown in FIG. 6, the blank holder 41 and the die 45 are spaced apart from each other, and the upper surface portion 42d of the punch 42 is blank. The plate-like workpiece W <b> 1 is held on the upper surface 41 b of the blank holder 41 in a state of being disposed below the upper surface 41 b of the holder 41. Then, the blank holder 41 of the press mold 40 is moved upward, the both ends in the short direction of the plate-like workpiece W1 are clamped by the blank holder 41 and the die 45, and then the punch 42 is moved upward, 42 is moved into the molding space 45c of the die 45, and the plate-like workpiece W1 is press-molded.

  FIG. 7 is an explanatory diagram for explaining a press molding process by the first press molding apparatus. FIG. 7A shows a state in which the plate-like workpiece W1 is sandwiched between the blank holder 41 and the die 45. FIG. 7B shows a state where the punch 42 is moved upward and the plate-like workpiece W1 is press-molded. FIG. 7B shows a state where the punch 42 is further moved upward and the plate-like workpiece W1 is press-formed. Show.

  As shown in FIG. 7A, the upper surface of the punch 42 is moved by moving the punch 42 into the molding space 45 c of the die 45 in a state where the plate-like workpiece W <b> 1 is sandwiched between the blank holder 41 and the die 45. The plate-like workpiece W1 is press-formed into a trapezoidal cross section by 42d. When the punch 42 is further moved upward, as shown in FIG. 7B, the plate-like workpiece W1 is further press-formed, and the plate-like workpiece W1 is formed into a predetermined shape by the punch 42 and the die 45.

  FIG. 8 is a perspective view showing a plate-like workpiece press-formed by the first press-forming apparatus, and FIG. 9 is a cross-sectional view of the plate-like workpiece taken along line Y9-Y9 in FIG. As shown in FIGS. 8 and 9, the plate-like workpiece W <b> 1 is such that the central portion in the short-side direction of the plate-like workpiece W <b> 1 sandwiched between the blank holder 41 and the die 45, excluding both short-side ends. The punch 42 is protruded in the moving direction and is press-formed into a convex shape, and has a convex top surface portion W2 and convex side surface portions W3 and W4 formed on both sides of the convex top surface portion W2.

  The press-formed plate-like workpiece W1 has a convex top surface portion W2 formed by the bottom surface portion 45d of the concave portion 45b provided on the die 45 and the top surface portion 42d of the punch 42, and the convex top surface portion W2 has a bottom surface portion 45d. A convex portion W2a that protrudes in a substantially circular arc shape in a direction opposite to the convex direction of the plate-like workpiece W1 by the convex portion 45m provided on the upper surface portion 42d and the concave portion 42m provided on the upper surface portion 42d of the plate-like workpiece W1. It is provided continuously in the longitudinal direction. Further, as shown in FIG. 8, the convex top surface portion W2 includes a right convex top surface portion W2b located on the right side of the convex portion W2a and a left convex top surface portion W2c located on the left side of the convex portion W2a. The sections W2b and W2c divided by the convex portion W2a of the convex top surface portion W2 are shaped so that the cross-sectional length in the short direction changes in the longitudinal direction of the plate-like workpiece W1.

  FIG. 10 is a perspective view showing the main part of the plate-like workpiece press-formed by the first press-forming apparatus. In FIG. 10, the plate-like workpiece shown in FIG. 8 is provided at the front end in the longitudinal direction. Only the vicinity of the tab portion is shown enlarged. In the present embodiment, before the press molding process by the first press molding apparatus, tab portions W2f extending in the longitudinal direction are formed at both ends in the longitudinal direction of the plate-like workpiece W1, and this tab portion W2f is A flat portion W2g that is press-molded by the bottom surface portion 45d of the die 45 and the upper surface portion 42d of the punch 42 and is formed in the same plane as the convex top surface portion W2, and a die 45 at the center in the short direction of the flat surface portion W2g. The protrusions 45m and the recesses 42m of the punch 42 are formed so as to have a protrusion W2h that protrudes in the shape of an arc of a cross section continuously from the protrusion W2a. The protruding portion W2h of the tab portion W2f is also a first portion W2i having the same cross-sectional shape as the convex portion W2a, and a second portion in which the radius of curvature of the protruding portion formed in a circular arc shape becomes smaller toward the tip. W2j. The tab portion provided at the rear side end in the longitudinal direction is similarly formed.

  On the right side of the convex top surface portion W2, the first inclined wall portion 45e and the right vertical wall portion 45f of the concave portion 45b provided in the die 45 and the first inclined wall portion 42e and the right vertical wall portion 42f of the punch 42 are provided. A convex side surface portion W3 is formed, and the convex side surface portion W3 includes a first right convex side surface portion W3a that is inclined obliquely downward to the right from the right convex top surface portion W2b of the convex top surface portion W2, and a first right side. And a second right convex side surface portion W3b extending downward in the vertical direction from the convex side surface portion W3a.

  On the other hand, on the left side of the convex top surface W2, the second inclined wall 45i and the left vertical wall 45j of the recess 45b provided in the die 45 and the second inclined wall 42i and the left vertical wall 42j of the punch 42 are provided. The convex side surface portion W4 is formed, and the convex side surface portion W4 includes a first left convex side surface portion W4a inclined to the left and obliquely downward from the left convex top surface portion W2c of the convex top surface portion W2. And a second left convex side surface portion W4b extending vertically downward from the left convex side surface portion W4a.

  The convex portion W2a, the right convex top surface portion W2b, and the left convex top surface portion W2c provided on the convex top surface portion W2 are the lower surface portion 22, the fourth inclined side surface portion 28, and the third inclined side surface of the front side frame 20, respectively. The first right convex side surface portion W3a of the convex side surface portion W3 is molded according to the shape of the left side surface portion 24 of the front side frame 20, and the second side surface of the convex side surface portion W3 is molded. The right convex side surface portion W3b is formed according to the shape of the second inclined side surface portion 26 and the upper surface portion 21 of the front side frame 20, and the first left convex side surface portion W4a of the convex side surface portion W4 is the front side. It is molded according to the shape of the right side surface portion 23 of the frame 20, and the second left convex side surface portion W 4 b of the convex side surface portion W 4 is according to the shapes of the first inclined side surface portion 25 and the upper surface portion 21 of the front side frame 20. Molded That. Further, in the tab portion W2f, the second portion W2i of the protruding portion W2h is formed according to the shape of the flange portion 22a of the front side frame 20.

  In this embodiment, when the plate-like workpiece W1 is press-molded, both ends in the short direction of the plate-like workpiece W1 are die 45 by the blank holder 41 as shown in FIGS. 7 (a) and 7 (b). Thus, wrinkles are prevented from being generated in the press-molded plate-like workpiece W1.

  In the present embodiment, the plate-like workpiece W1 is sandwiched between the blank holder 41 of the press mold 40 and the die 45, and the punch 42 of the press mold 40 is moved into the molding space 45c of the die 45 so that the plate The blank workpiece 41 is press-molded, but with the punch 42 fixed, the blank holder 41 holding the plate-shaped workpiece W1 and the die 45 are moved relative to the punch 42 to perform press molding. May be.

  After the plate-like workpiece W1 is press-molded by the first press-molding apparatus having the press-molding die 40 in this way, the press-molded plate-like workpiece W1 is subjected to second trimming means (not shown) in FIG. The portion located below the trimming line L2 shown in FIG. 2 is trimmed, and both end portions W5 in the short direction of the plate-like workpiece W1 are cut off.

  Thereafter, the plate-like workpiece W1 is trimmed by a third trimming means (not shown) and a portion (hatched portion hatched) defined by the trimming line L3 shown in FIG. Piercing is performed on an inner portion (a cross-hatched portion) of the piercing line L4 shown in FIG.

  When the tab portion W2f is trimmed by the third trimming means and pierced by the piercing means, both side portions of the first portion W2i of the protruding portion W2h are cut off and the substantially circular opening W2k is formed in the flat surface portion W2g. Is formed. As will be described later, the opening W2k is used as a positioning hole for positioning the convex portion W2a with respect to a press mold that press-molds the convex portion W2a. On the other hand, the second portion W2j of the protruding portion W2h is, as will be described later, a flange for press-molding at the same time when the convex portion W2a is press-molded, and then bending and joining with another member such as a bracket. Used as a part. Note that the tab W2f provided at the rear end of the plate-like workpiece W1 is similarly trimmed and pierced after being press-molded.

  In the present embodiment, after the plate-like workpiece W1 is trimmed by the second trimming means, it is trimmed by the third trimming means and pierced by the piercing means, but the second trimming and the third trimming are performed. The piercing may be performed at the same time.

  Next, the plate-like workpiece W1 is an end portion of the convex side surface portions W3 and W4, specifically, the convex top surface portion W2 of the second right convex side surface portion W3b of the convex side surface portion W3 shown in FIG. The end W3e opposite to the side and the end W4e opposite to the convex top surface W2 side of the second left convex side surface W4b of the convex side surface W4 are bent inward. FIG. 11 is a cross-sectional view showing a bending mold of a bending apparatus for bending an end portion of a convex side surface portion of a plate-like workpiece.

  As shown in FIG. 11, the end portions W3e, W4e opposite to the convex top surface portion W2 side of the convex side surface portions W3, W4 of the plate-like workpiece W1 are bent to the inward side of the plate-like workpiece W1. The bending apparatus includes a first die 51 for holding a plate-like workpiece W1 press-formed in a convex shape, a second die 52 fitted to the outer peripheral surface 51a of the first die 51, and a second die 52. The third die 53 that supports the second die 52, the fourth die 54 disposed below the first die 51, and the first die 51 are disposed so as to be opposed to each other by a punch moving mechanism (not shown). A bending mold 50 having a punch 55 configured to be movable in a direction.

  The first die 51 of the bending mold 50 is urged upward by urging means (not shown), and is arranged in a state of being separated from the fourth die 54 as shown in FIG. The upper surface 51b of the first die 51 is formed by bending the right side portion of the convex side surface portion W4 of the press-formed plate-like workpiece W1, specifically, the end portion W4e of the second left convex side surface portion W4b. Therefore, the second left convex side surface portion W4b is bent so that the end portion W4e to be bent is positioned above the second die 52 so as to hold the press-formed plate-like workpiece W1. It is formed according to the shape of the shape top surface portion W2 and the convex side surface portion W4. Further, the left side portion of the upper surface 51b of the first die 51 is formed by bending the convex side surface portion W3 of the press-formed plate-like workpiece W1, specifically, the end portion W3e of the second right convex side surface portion W3b. In order to hold the plate-like workpiece W1 press-formed in a state where the end portion W3e to be bent of the second right convex side surface portion W3b is positioned above the second die 52, It is formed according to the shape of the shape top surface portion W2 and the convex side surface portion W3.

  On the other hand, the punch 55 of the bending mold 50 includes a first punch 55a for pressing the plate-like workpiece W1 held on the right side portion of the upper surface 51b of the first die 51, and an upper surface 51b of the first die 51. And a second punch 55b for pressing the plate-like workpiece W1 held on the left side.

  In the bending apparatus, the first die 51 and the punch 55 are also tabs provided at both ends in the longitudinal direction of the plate-like workpiece W1 when bending the end portions W3e and W4e of the convex side portions W3 and W4. It is formed so as not to interfere with the portion W2f. In addition, the bending apparatus includes a bending molding apparatus control unit that controls the movement mechanism of the punch 55. The bending molding apparatus control unit includes the punch 55, specifically, the first punch 55a and the first punch 55a. Controls the vertical movement of the second punch 55b.

  When bending the end portions W3e and W4e of the convex side portions W3 and W4 of the plate-like workpiece W1 using a bending device, as shown in FIG. 11, the first die 51 is moved by the urging means. In a state of being biased upward, the press-formed plate-like workpiece W1 is held on the right side portion of the upper surface 51b of the first die 51 with the first left convex side surface portion W4a on the lower side. Then, the punch 55 of the bending mold 50 is moved downward, and bending is performed by the punch 55 and the second die 52.

  12 and 13 are explanatory diagrams for explaining the bending process. FIG. 12 shows a state where the punch is lowered and the punch and the plate-like workpiece are in contact with each other. FIG. 13 shows the punch further lowered. The first die and the fourth die are in contact with each other, and the end of the convex side surface portion of the plate-like workpiece is bent and formed.

  As shown in FIG. 12, when the punch 55 is lowered while the plate-like workpiece W1 is held on the upper surface 51b of the first die 51, the first punch 55a of the punch 55 and the plate-like workpiece W1 are moved. Contact. When the punch 55 is further moved downward from this state, the first punch 55a of the punch 55 and the first punch 55a of the punch 55 are sandwiched between the first punch 55a of the punch 55 and the first die 51. The second die 52 and the end portion W4e of the second right convex side surface portion W4b of the convex side surface portion W4 are bent inward, and the first die 51 is the fourth die as shown in FIG. When it comes into contact with the die 54, the downward movement of the punch 55 is stopped, and the bending is finished.

  When the bending of the end W4e of the convex side surface portion W4 of the plate-like workpiece W1 is completed, the punch 55 is moved upward, and the plate-like workpiece W1 held by the first die 51 and the first die 51 is moved upward. Is moved back to the initial position. Then, as shown by a two-dot chain line in FIG. 13, the plate-like workpiece W1 press-formed in a convex shape is rotated 90 degrees so that the plate-like workpiece W1 has the first right convex side surface portion W3a on the lower side. The second punch 55b and the second die 52 are similarly held by the left portion of the upper surface 51b of the first die 51 and the end of the second left convex side surface portion W3b of the convex side surface portion W3. The portion W3e is bent inward.

  After the end portions W3e and W4e on the opposite side of the convex side surface portions W3 and W4 of the plate-like workpiece W1 are bent inward in this way, the plate-like workpiece W1 is The convex portion W2a provided on the convex top surface portion W2 is press-molded in a direction protruding in the convex shape of the plate-like workpiece W1, which is the direction opposite to the protruding direction of the convex portion W2a, and the convex on both sides of the convex top surface portion W2. Each of the side surfaces W3 and W4 is displaced inward to make the plate-like workpiece W1 closed.

  FIG. 14 is a side view of a press molding die of a second press molding apparatus for press molding a convex part of a plate-like workpiece, and FIG. 15 is a second press molding apparatus along the line Y15-Y15 in FIG. FIG. 16 is a cross-sectional view of the press forming die of the second press forming apparatus along the line Y16-Y16 in FIG. 15, and in FIGS. Is shown held in the press mold. FIGS. 17 and 18 are explanatory views for explaining a press forming process by the second press forming apparatus, and FIG. 17 shows the press forming in which the convex portion of the plate-like workpiece is press formed. FIG. 18 is a cross-sectional view of the press mold showing a state in which the convex portions of the plate-like workpiece are press-molded.

  As shown in FIGS. 14 to 16, the second press molding apparatus for press-molding the convex portion W2a of the plate-like workpiece W1 to make a closed cross-section includes a die 61 for holding the plate-like workpiece W1, A core die 65 that is disposed above the die 61 and press-molds the convex portion W2a of the plate-like workpiece W1 held by the die 61 in a direction protruding in the convex shape of the plate-like workpiece W1, and a core die 65 The convex portion W2a of the core die 65 is pressed between the convex side portions W3, W4e, which are disposed above the convex portions W2a of the plate-like workpiece W1 and formed into a closed cross section by pressing. There is provided a press mold 60 having a punch 67 for pressing and pressing to a surface portion opposite to the surface portion.

  The die 61 of the press mold 60 includes an upper surface portion 61a formed in a substantially planar shape in order to hold the convex top surface portion W2 of the plate-like workpiece W1. The die 61 is provided with two columnar positioning pins 63 for positioning the tab portion W2f of the plate-like workpiece W1 so as to protrude from the upper surface portion 61a of the die 61 and separated in the longitudinal direction. The positioning pin 63 is for fitting the opening W2k of the tab portion W2f provided at both ends in the longitudinal direction of the plate-like workpiece W1. By fitting the opening W2k to the positioning pin 63, the die 61 is fitted. Accordingly, the tab portion W2f is positioned, and the plate-like workpiece W1 is positioned at a predetermined position of the die 61. The positioning pin 63 is also configured to be movable in the vertical direction by a moving mechanism (not shown) so that the core die 65 is pulled out in the longitudinal direction of the plate-like workpiece W1 after the plate-like workpiece W1 is closed.

  The die 61 of the press mold 60 also cuts a part of the tab portion W2f of the plate-like workpiece W1 and bends part of the cut tab portion W2f to both ends in the longitudinal direction of the plate-like workpiece W1. A concave portion 64 that is recessed from the upper surface portion 61 is provided so as to form a flange portion. The concave portion 64 is provided so as to correspond to the first portion W2i of the protruding portion W2h of the tab portion W2f of the plate-like workpiece W1 that is positioned and held with respect to the die 61.

  The core die 65 of the press mold 60 is disposed above the die 61 so as to press-mold the convex portion W2a provided on the convex top surface portion W2 of the plate-like workpiece W1 in the direction opposite to the protruding direction. . The core mold 65 is formed longer in the longitudinal direction than the plate-like workpiece W1, and includes an upper surface portion 65a, a lower surface portion 65b, a right side surface portion 65c, and a left side surface portion 65d as shown in FIG. It is formed in a rectangular shape and is formed continuously in the longitudinal direction. The upper surface portion 65 a of the core mold 65 is formed according to the shape of the upper surface portion 21 of the front side frame 20, and the lower surface portion 65 b of the core mold 65 is formed according to the shape of the lower surface portion 22 of the front side frame 20. In addition, the cross-sectional width in the short direction of the lower surface portion 65b is set to be substantially the same as the cross-sectional length of the convex portion W2a of the plate-like workpiece W1.

  As shown in FIG. 15, the core die 65 of the press mold 60 is also provided with concave portions 65e that are recessed in the vicinity of both ends in the longitudinal direction of the lower surface portion 65b. A movable slide portion 69 is disposed. The slide portion 69 is formed in a taper shape so that the lower surface portion 69a can cut the tab portion W2f of the plate-like workpiece W1, and the inner side surface portion 69b is cut off of the plate-like workpiece W1. The tab portion W2f is formed to extend in a substantially vertical direction so that a part of the tab portion W2f can be bent.

  Further, as shown in FIG. 18, the core die 65 of the press mold 60 has a narrower cross-sectional width than that of the front side frame 20 when the plate-like workpiece W1 is closed. The first left convex side surface portion W4a of the plate-like workpiece W1 in which the cross-sectional width L31 between the right side surface portion 65c and the left side surface portion 65d of the child mold 65 corresponds to the right side surface portion 23 and the left side surface portion 24 of the front side frame 20. And the first right convex side surface portion W3a is formed to have a cross-sectional width narrower than the cross-sectional width L32.

  The core mold 65 formed in this manner is moved in the vertical direction by a core-type vertical movement mechanism (not shown), and the plate-like workpiece W1 is moved by a core-type front-back movement mechanism (not shown). Is closed in the longitudinal direction of the closed cross-section member formed in the closed cross-section shape after the closed cross-section. Further, as described above, the slide part 65 is moved in the vertical direction with respect to the core mold 65 by a slide part vertical movement mechanism (not shown).

  The punch 67 of the press mold 60 has end portions W3e and W4e of the plate-like workpiece W1 that are abutted to each other to form a closed cross section, and then the ends of the abutted convex side portions W3 and W4. The parts W3e and W4e are pressed against the convex top surface W2 of the core 65, specifically, the surface (lower surface) 65b opposite to the surface (lower surface) 65b that presses the convex W2a. This is a punch for molding, and is moved up and down by a punch moving mechanism (not shown).

  The second press molding apparatus is provided with a second press molding apparatus control unit (not shown) for comprehensively controlling the second press molding apparatus, and the second press molding apparatus. The control unit controls various operations such as a positioning pin 63, a core die 65, a punch 67, and a moving mechanism of the slide portion 69.

  The second press molding apparatus provided with the press mold 60 configured as described above is configured such that the plate workpiece W1 is placed on the die 61 of the press mold 60 and the upper surface 61a provided on the die 61 is placed on the plate workpiece. In a state where the convex top surface portion W2 of W1 is held, the convex portion W2a of the plate-like workpiece W1 is press-molded by the core die 65 in the direction of projecting into the convex shape of the plate-like workpiece W1, and plate-like The projecting side surface portions W3 and W4 on both sides of the projecting top surface portion W2 of the workpiece W1 can be displaced inward to make a closed cross section.

When press-molding the convex portion W2a of the plate-like workpiece W1 using the second press molding apparatus,
As shown in FIG. 15, in the plate-like workpiece W1, the opening W2k provided in the tab portion W2f of the plate-like workpiece W1 is fitted into the positioning pin 63 arranged so as to protrude from the upper surface portion 61a of the die 61. The tab portion W2f of the plate-like workpiece W1 is positioned with respect to the die 61. Accordingly, the plate-like workpiece W1 is positioned at a predetermined position with respect to the press mold 60 so that the convex portion W2a is press-molded and crushed by the lower surface portion 65b of the core die 65, and the convex top surface portion W2 is formed as a die. 61 is held by the upper surface portion 61 a of the 61.

  When the plate-like workpiece W1 is held by the die 61, the core die 65 is moved downward in a state where the slide portion 69 is disposed in the recess 65e, and the convex portion W2a of the plate-like workpiece W1 is moved to the core die 65. Is pressed downward in the direction opposite to the protruding direction of the convex portion W2a, so that the left convex top surface portion W2c and the convex side surface portion W4 are plates with the intersection of the convex portion W2a and the left convex top surface portion W2c as a fulcrum. The right convex top surface W2b and the convex side W3 are displaced from the intersection of the convex W2a and the right convex top W2b as a fulcrum. It is displaced inward in the closing direction.

  As shown in FIG. 18, when the convex portion W2a of the plate-like workpiece W1 is press-molded by the core mold 65, the convex portion W2a is crushed and the core-shaped die 65 and the die 61 press the plate-shaped workpiece W1. While W2d is formed, the convex side portions W3 and W4 are displaced inward, the end portions W3e and W4e of the convex side portions W3 and W4 are abutted, and the plate-like workpiece W1 is closed. It becomes.

  In the present embodiment, as shown in FIG. 17, when the convex portion W2a of the plate-like workpiece W1 is press-molded, the protruding portions W2h of the tab portions W2f provided at both ends in the longitudinal direction of the plate-like workpiece W1 are also provided. Further, the tab part W2f is press-formed by the lower surface part 65b of the core mold 65, and the protruding part W2h is crushed and formed into a flat shape.

  FIGS. 14 to 18 show the cross section corresponding to the cross section shown in FIG. 3A of the front side frame 20 in order to explain the press forming process by the second press forming apparatus. Other cross sections such as the cross section corresponding to the cross section shown in FIG. 3B are simultaneously press-molded to form a closed cross section.

  FIG. 19 is an explanatory diagram for explaining a press molding process by the second press molding apparatus with respect to a cross section corresponding to the cross section shown in FIG. 3B of the front side frame, and FIG. FIG. 19B shows a state where the core 65 and the convex portion W2a of the plate-like workpiece W1 are in contact with each other. FIG. 19B shows a state where the convex portion W2a of the plate-like workpiece W1 is press-molded by the core die 65. ing.

  Also for the cross section corresponding to the cross section shown in FIG. 3B of the front side frame 20, when the core mold 65 is moved downward with the plate-like workpiece W1 held by the die 61, FIG. ), When the lower surface portion 65b of the core die 65 and the convex portion W2a of the plate-like workpiece W1 come into contact with each other, and the core die 65 is further moved downward from this state, the left convex top surface portion W2c. And the convex side surface W4 is displaced inward in the direction of closing the plate-like workpiece W1 with the intersection of the convex W2a and the left convex top surface W2c as a fulcrum, and the right convex top surface W2b and the convex side surface W3 is displaced inward in the direction of closing the plate-like workpiece W1 with the intersection of the convex portion W2a and the right convex top surface portion W2b as a fulcrum. Then, when the convex portion W2a is press-molded by the core die 65, the convex portion W2a is crushed and pressed by the core die 65 and the die 61 onto the plate-like workpiece W1 as shown in FIG. While W2d is molded, the end portions W3e and W4e of the convex side portions W3 and W4 are abutted to form a closed cross section.

  Thus, in this embodiment, the state where the opening W2k as the positioning hole of the tab portion W2f provided at both ends in the longitudinal direction of the plate-like workpiece W1 is fitted to the positioning pin 63 provided in the die 61. The convex part W2a is press-molded. Thus, the second press molding is performed in a state where the plate-like workpiece W1 and the press-molding die 60 are held in a predetermined positional relationship, and the ends of the convex side portions W3 and W4 on both sides of the plate-like workpiece W1. The portions W3e and W4e can be properly matched.

  By pressing the convex part W2a of the plate-like workpiece W1 in the direction opposite to the protruding direction, the convex part W2a is crushed to form a press-molding surface W2d and convex side surface parts W3 on both sides of the convex top surface part W2. , W4 is displaced inward to make a butted closed cross section, part of the tab part W2f provided at both ends of the plate-like workpiece W1 is cut and part of the tab part W2f is bent. To form a flange portion.

  FIG. 20 is a longitudinal cross-sectional view of the press mold showing a state in which a part of the tab portion of the plate workpiece is cut and bent after the convex portion of the plate workpiece is press molded. As shown in FIG. 20, after the convex portion W2a of the plate-like workpiece W1 is press-molded, the slide portion 69 of the core die 65 is moved downward, and the protruding portion of the tab portion W2f is moved by the lower surface portion 69a of the slide portion 69. The flat press-molded portion composed of the first portion W2i of W2h is cut and bent in a substantially right angle direction by the side surface portion 69b of the slide portion 69, and flange portions are provided at both ends in the longitudinal direction of the plate-like workpiece W1. W2l is formed.

  After a part of the tab part W2f provided at both ends of the plate-like workpiece W1 is cut and a part of the tab part W2f is bent to form the flange part W21, the closed section of the plate-like workpiece W1 is made. The end portions W3e, W4e of the convex side surface portions W3, W4 are pressed against the surface portion 65a opposite to the surface portion 65b that presses the convex portion W2a of the core mold 65, and are determined and pressed.

  FIG. 21 is an explanatory diagram for explaining the final pressing process, and FIG. 21 shows a state after the final pressing process. When the end faces W3e and W4e of the convex side portions W3 and W4 having a closed cross-section of the plate-like workpiece W1 are pressed against the core die 65 to be pressed and formed, the plate-like workpiece W1 is disposed above the core die 65. A punch 67 configured to be movable in the vertical direction is used.

  When the punch 67 of the press mold 60 is moved downward so as to press the end portions W3e and W4e of the convex side portions W3 and W4 having a closed cross section of the plate-like workpiece W1, as shown in FIG. Further, the end portions W3e, W4e of the convex side portions W3, W4 having a closed cross section of the plate-like workpiece W1 are pressed by the punch 67, and opposite to the surface portion 65b for pressing the convex portion W2a of the core die 65. It is pressed against the surface portion 65a and is determined to be press-molded, and the surface portion W6 corresponding to the upper surface portion 21 of the front side frame 20 is reliably formed by the punch 67 and the core die 65.

  21 shows the cross section corresponding to the cross section shown in FIG. 3A of the front side frame 20, but other cross sections such as the cross section corresponding to the cross section shown in FIG. Are simultaneously pressed and pressed. Note that the punch 67 is a surface portion on the opposite side to the surface portion 65b that presses the convex portion W2a of the core die 65 between the end portions W3e, W4e of the convex side surface portions W3, W4 having a closed cross section of the plate-like workpiece W1. A fixed press forming means for pressing and pressing to 65a is formed.

  In this way, the end portions W3e and W4e of the projecting side surface portions W3 and W4 of the plate-like workpiece W1 having a closed cross section are connected to the surface portion 65a opposite to the surface portion 65b that presses the convex portion W2a of the core die 65. By pressing and pressing, it is possible to obtain a high molding accuracy with respect to the surface opposite to the press molding surface W2d by a relatively simple method.

  After the end portions W3e and W4e of the projecting side surfaces W3 and W4 having a closed cross section of the plate-like workpiece W1 are pressed and formed by the punch 67 and the core die 65, the slide portion 69 becomes the core die 65. The core 65 is extracted in the longitudinal direction of the plate-like workpiece W1 in a state in which it is moved into the recess 65e and the positioning pin 63 is moved downward, and the punch 67 is moved upward. Then, the end portions W3e and W4e of the convex side surface portions W3 and W4 are welded by a welding device such as laser welding as a welding means for welding the end portions W3e and W4e of the convex side surface portions W3 and W4 having a closed cross section. Are joined continuously in the longitudinal direction, and the front side frame 20 as a closed section member formed in a closed section shape is manufactured without forming a flange portion used only for manufacturing the closed section member. The front side frame 20 is integrally formed with flange portions 22a bent at substantially right angles to the lower surface portion 22 at both ends in the longitudinal direction.

  FIG. 22 is a view showing a state in which a bracket is joined to the flange portion of the front side frame. As shown in FIG. 22, the flange portion 22a formed integrally with the front side frame 20 is a front portion of a bracket or the like. It is possible to easily join the other member 30 extending in the direction orthogonal to the longitudinal direction of the side frame 20.

  In the present embodiment, a closed cross-section member 20 formed in a closed cross-sectional shape from a metal plate-like workpiece W1 by the first press forming apparatus, the second press forming apparatus, the bending apparatus, and the welding apparatus. A metal closed cross-section member manufacturing apparatus is manufactured, and the metal closed cross-section member manufacturing apparatus accurately manufactures a closed cross-section member formed in a closed cross-section shape from a metal plate-like workpiece W1. can do.

  In the present embodiment, the plate-like workpiece W1 is moved to the die 45 by moving the punch 42 into the molding space 45c in a state where the plate-like workpiece W1 is sandwiched between the blank holder 41 and the die 45 of the press-molding die 40. While projecting in the moving direction of the punch 42 with respect to 45 and press-molding into a convex shape, a convex portion W2a projecting in the opposite direction is formed on the convex top surface portion W2 formed into a convex shape of the plate-like workpiece W1. For example, other press molding such as overhang may be used.

  Further, the convex side surface portions W3 and W4 of the plate-like workpiece W1 are bent and the end portions W3e and W4e opposite to the convex top surface portion W2 side of the W4 are bent and formed into a closed cross section. Further, only one end of the convex side surfaces W3 and W4 of the plate-like workpiece W1 may be bent inward and then closed, and the closed cross section may be formed without bending. It is also possible to make it.

  In the present embodiment, a part of the tab portion W2f provided at both end portions in the longitudinal direction of the plate-like workpiece W1 is cut. However, when the flange portion is not formed, in the second press molding step. You may make it cut | disconnect the tab part W2f used for positioning with respect to the press-molding die 60 after the press-molding of the convex part W2a.

  Thus, in this embodiment, when manufacturing the metal closed cross-section member 20 by forming the plate-like workpiece W1 in a closed cross-sectional shape, the plate-like workpiece W1 is press-molded into a convex shape and the convex top surface portion W2. The first press molding step for forming the convex portion W2a and the convex portion W2a are crushed by pressing the convex portion W2a, and the convex side surface portions W3 and W4 on both sides are displaced inward and closed. A second press forming step of cross-section, and further comprising a tab portion forming step of integrally forming a tab portion W2f at the longitudinal end portion of the plate-like workpiece W1 in the convex portion W2a. The molding step is performed by positioning the tab portion W2f with respect to a press mold 60 that press-molds the convex portion W2a in the direction opposite to the protruding direction. Thus, the second press molding is performed in a state where the plate-like workpiece W1 and the press-molding die 60 are held in a predetermined positional relationship, and the ends of the convex side portions W3 and W4 on both sides of the plate-like workpiece W1. The parts W3e and W4e can always be brought close to each other correctly, and the metal closed cross-section member can be accurately manufactured by a relatively simple method without complicating a molding apparatus such as a molding die and a molding process. In the case of manufacturing a deformed closed cross-section member whose cross-sectional shape changes in the longitudinal direction, the above effect can be obtained effectively.

  The press mold 60 includes a die 61 that holds the plate-like workpiece W1, and a core die 65 that press-forms the convex portion W2a in a direction opposite to the protruding direction while holding the plate-like workpiece W1 on the die 61. The second press molding process can be positioned with respect to the die 61 fixed in the second press molding process by positioning the tab portion W2f with respect to the die 61. It can be obtained effectively.

  Further, a positioning hole W2k is provided in the tab portion W2f, and a positioning pin 63 is provided in the press mold 60. In the second press molding process, the positioning hole W2k is fitted to the positioning pin 63, thereby press forming. By positioning the tab portion W2f with respect to the mold 60, positioning can be performed by a relatively simple and reliable method, and the above-described effect can be obtained with certainty.

  Furthermore, between the first press molding step and the second press molding step, the end portions W3e, W4e on the opposite side of the convex top surface portion W2 side of the plate-like workpiece W1 are placed on the plate. By further comprising a bending process for bending inward of the workpiece W1, the convex side portions W3 and W4 are displaced when the convex side portions W3 and W4 on both sides are displaced inward. A metal closed cross-section member can be manufactured more accurately with less inward displacement.

  Furthermore, after the second press forming step, a further step of welding the end portions W3e, W4e of the convex side portions W3, W4 having a closed cross section of the plate-like workpiece W1 is provided. The joining strength of the cross-sectional member can be increased, and a stronger closed cross-sectional member can be manufactured.

  In the above-described embodiment, in the second press molding apparatus having the press mold 60 shown in FIGS. 14 to 16, the convex top surface portion W2 of the plate-like workpiece W1 is held on the top surface portion 61a provided on the die 61. In this state, the convex portion W2a of the plate-like workpiece W1 is press-molded in the direction opposite to the protruding direction of the convex portion W2a by the core die 65 of the press-molding die 60, but a concave portion is provided on the upper surface portion 61a of the die 61. In addition, it is also possible to press-mold the convex portion W2a in the concave portion in the direction opposite to the protruding direction of the convex portion W2a by the core mold of the press-molding die.

  FIG. 23 is an explanatory diagram for explaining another method of manufacturing the metal closed cross-section member according to the present embodiment, in which the press of the second press-forming device for press-forming the convex portion of the plate-like workpiece. A mold is shown. The press mold 100 shown in FIG. 23 is the same as the press mold 60 except that a recess is formed in the die 61 of the press mold 60. Omitted. FIG. 23 shows a state where the plate-like workpiece W1 is held by the press mold 100.

  As shown in FIG. 23, the die 101 of the press mold 100 is provided with a concave portion 102 that is recessed in the upper surface portion 101a for holding the convex top surface portion W2 of the plate-like workpiece W1. The concave portion 102 includes a bottom surface portion 102a, side wall portions 102b and 102c, specifically, a right side wall portion 102b located on the right side and a left side wall portion 102c located on the left side in FIG. It extends.

  The bottom surface portion 102a of the concave portion 102 provided in the die 101 is formed according to the shape of the lower surface portion 22 of the front side frame 20, and the sectional length of the convex portion W2a provided on the convex top surface portion W2 of the plate-like workpiece W1. The cross section length L21 is substantially the same as the length L11. Further, the right side wall portion 102b of the concave portion 102 is formed to have a cross-sectional length L22 substantially the same as the shortest cross-sectional length L12 of the left convex top surface portion W2c, and the left side wall portion 102c of the concave portion 102 is formed. The right convex top surface portion W2b is formed to have the same cross-sectional length L23 as the shortest cross-sectional length L13, and the inclination angle of the side wall portions 102b and 102c of the concave portion 102 with respect to the bottom surface portion 102a is respectively According to the shape of the front side frame 20, it is formed at a substantially constant predetermined angle in the longitudinal direction.

  When press-molding the convex portion W2a of the plate-like workpiece W1 using the second press-molding apparatus provided with the press-molding die 100, the plate-like workpiece W1 is formed of the press-molding die 100 as shown in FIG. In the state where the opening portion W2k provided in the tab portion W2f of the plate-like workpiece W1 is fitted to the die 101 and the tab portion W2f of the plate-like workpiece W1 is positioned with respect to the die 101, the die 101 is positioned. The convex portion W2a of the plate-like workpiece W1 is disposed on the concave portion 102 provided in the upper surface portion 101a of the die 101 so that the central axis in the short direction thereof substantially coincides with the convex portion W2a. .

  When the plate-like workpiece W1 is held by the die 101, the core die 65 is moved downward, and the convex portion W2a of the plate-like workpiece W1 is pressed downward in the direction opposite to the protruding direction by the core die 65, thereby The left convex top surface portion W2c and the convex side surface portion W4 are inward in the direction of closing the plate-like workpiece W1 with the shoulder portion 102e of the die 101, which is the intersection of the right side wall portion 102b of the concave portion 102 and the upper surface portion 101a as a fulcrum. The plate-like workpiece W1 is displaced with the shoulder portion 102f of the die 101, which is the intersection of the left side wall portion 102c and the upper surface portion 101a of the concave portion 102, as the right convex top surface portion W2b and the convex side surface portion W3. It is displaced inward in the closing direction.

  FIG. 24 is a diagram showing a state in which the convex portions of the plate-like workpiece are press-molded by the second press-molding apparatus having the press-molding die shown in FIG. As shown in FIG. 24, when the convex part W2a of the plate-like workpiece W1 is press-molded by the core mold 65, the convex part W2a is crushed and the press mold surface W2d is molded by the core mold 65 and the die 101. At the same time, the convex side surface portions W3 and W4 on both sides of the convex top surface portion W2 are displaced inward, and the end portions W3e and W4e of the convex side surface portions W3 and W4 are brought into contact with each other, so that the plate-like workpiece W1 Is closed.

  Even when the second press molding apparatus provided with the press mold 100 is used, the plate workpiece W1 can be positioned with respect to the press mold 100 when the convex portion W2a of the plate workpiece W1 is press molded. Therefore, a metal closed cross-section member can be accurately manufactured by a relatively simple method without complicating a molding apparatus such as a molding die and a molding process. When a metal closed cross-section member is manufactured from a metal plate-like workpiece using the second press molding apparatus provided with the press mold 100, the cross-sectional lengths L12 and L13 of the convex top surface portions W2c and W2b are long. Even when the direction changes, the cross-sectional lengths L22 and L23 of the side wall portions 102b and 102c of the concave portion 102 provided in the die 101 of the press mold 100 are respectively the cross-sectional lengths L12 and L13 of the convex side surface portions W2c and W2b. The convex top surface portion corresponding to the third inclined side surface portion 27 and the fourth inclined side surface portion 28 of the front side frame 20 is formed by press molding using the die 101 set substantially the same as the shortest portion of the front side frame 20. W2c and W2b can be raised by being press-molded at substantially equal timing in the longitudinal direction, and the press-molding can be stably performed.

  In the above-described embodiment, a part of the tab portion W2f or the entire tab portion W2f provided at both ends in the longitudinal direction of the plate-like workpiece W1 and used for positioning with respect to the press molds 60, 100 is used in the second press. Although it cut | disconnects after shaping | molding, it can also be used in order to attach with another member, without cut | disconnecting tab part W2f.

  FIG. 25 is an explanatory diagram for explaining a method used for attaching the tab portion to another member, and FIG. 26 is a sectional view showing a state in which the two closed sectional members shown in FIG. 25 are attached. . As shown in FIG. 25, the two closed cross-section members 120 and 130 are each formed into a substantially octagonal cross section from a plate-like workpiece by the method for manufacturing a metal closed cross-section member according to the present embodiment, like the front side frame 20. The tab portions 122a and 132a used for positioning in the second press molding are respectively formed on the lower surface portions 122 and 132 along the lower surface portions 122 and 132 without being cut. The tab portions 122a and 132a are formed to have substantially the same cross-sectional width as that of the lower surface portions 122 and 132 in the short direction.

  The closed cross-section member 120 is formed so as to be fitted in the closed cross-section member 130, and an opening 122b as a positioning hole is formed in the tab portion 122a. The closed cross-section member 120 is formed with a closed cross-sectional shape, and then a bolt insertion hole 121a is formed in the upper surface portion 121, and a nut N1 is fixed inside the upper surface portion 121 corresponding to the bolt insertion hole 121a. . Also on the tab portion 122a, a nut N2 is fixed inside the tab portion 122a corresponding to the opening portion 122b.

  On the other hand, the closed cross-section member 130 is similarly formed with an opening 132b as a positioning hole in the tab portion 132a, and a bolt insertion hole 131a is formed in the upper surface portion 131 after being formed in a closed cross-sectional shape. The closed cross-section member 130 is slightly larger than the closed cross-section member 120 so that the closed cross-section member 120 can be fitted together.

  As shown in FIG. 26, the closed cross-section members 120 and 130 formed in this way are aligned with the opening 132 b of the tab portion 132 a of the closed cross-section member 130 and the bolt insertion hole 121 a of the closed cross-section member 120. The opening 122b of the tab section 122a of the closed cross-section member 120 and the bolt insertion hole 131a of the closed cross-section member 130 are fitted together, and the closed cross-section member 120 and the closed cross-section member 130 are connected using bolts B1 and B2. It can be fastened and fixed. Thus, the positioning holes 122b and 132b of the tab portions 122a and 132a can be used as mounting holes for mounting to other members without cutting the tab portions 122a and 132a used for positioning. In addition, attachment strength can be further improved by welding the fitting part of the closed cross-section members 120 and 130 from the outer peripheral side by laser welding or the like.

  FIG. 27 is an explanatory view for explaining another method used for attaching the tab portion to another member, and FIG. 28 is a sectional view showing a state in which the two closed sectional members shown in FIG. 27 are attached. It is. In another method used to attach the tab portion shown in FIGS. 27 and 28 to another member, two closed cross-section members are fitted together so that the tab portions overlap each other.

  As shown in FIGS. 27 and 28, the two closed cross-section members 140 and 150 are each substantially octagonal in cross section from the plate-like workpiece by the metal closed cross-section member manufacturing method according to the present embodiment, like the front side frame 20. The tab portions 142a, 152a used for positioning in the second press molding are formed on the lower surface portions 142, 152 along the lower surface portions 142, 152 without being cut. The tab portions 142a and 152a are formed to have substantially the same cross-sectional width as that of the lower surface portions 142 and 152 in the short direction.

  The closed cross-section member 140 is formed so as to be fitted into the closed cross-section member 150, and an opening 142b as a positioning hole is formed in the tab portion 142a. Further, the closed cross-section member 140 is formed with a closed cross-sectional shape, and then a bolt insertion hole 142c is formed in the lower surface portion 142, and a nut N3 is fixed inside the lower surface portion 142 corresponding to the bolt insertion hole 142c, Also on the tab portion 142a, a nut N4 is fixed to the inside of the tab portion 142a corresponding to the opening 142b.

  Similarly, the closed cross-section member 150 is also formed with an opening 152b as a positioning hole in the tab portion 152a, and after being formed in a closed cross-sectional shape, a bolt insertion hole 152c is formed in the lower surface portion 152. The member 150 is slightly larger than the closed cross-section member 140 so that the member 150 can be fitted with the closed cross-section member 140.

  As shown in FIG. 28, the closed cross-section members 140 and 150 formed in this way are closed while the opening 142 b of the tab portion 142 a of the closed cross-section member 140 and the bolt insertion hole 152 c of the closed cross-section member 150 are aligned. The opening 152b of the tab portion 152a of the cross-sectional member 150 and the bolt insertion hole 142c of the closed cross-sectional member 140 are fitted together, and the closed cross-sectional member 140 and the closed cross-sectional member 150 are fastened using bolts B3 and B4. Can be fixed. Thus, the positioning holes 142b and 152b of the tab portions 142a and 152a used for positioning can be used as mounting holes for mounting to other members.

  The present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the gist of the present invention.

  The present invention relates to the manufacture of a metal closed cross-section member that manufactures a closed cross-section member from a metal plate-like workpiece. For example, a vehicle body member formed in a closed cross-section shape such as a front side frame, a rear side frame, or a dash cross member. It can be effectively applied in manufacturing.

20 Front side frame 60, 100 Second press mold 61, 101 Second press mold die 63 Positioning pin 65 Core mold of second press mold 65a Core mold of second press mold 65a Upper surface portion 65b Lower surface portion of core die of second press molding die 120, 130, 140, 150 Closed cross-section member 122a, 132a, 142a, 152a Tab portion 122b, 132b, 142b, 152b Tab portion opening W1 Plate shape Workpiece W2 Convex top surface portion W2a Convex portion formed on convex top surface portion W2f Tab portion W2k Tab portion opening W3, W4 Convex side surface portion W3e, W4e

Claims (6)

A metal plate-like workpiece is press-formed into a convex shape, and a convex portion protruding in a direction opposite to the convex shape of the plate-like workpiece is formed on the convex top surface portion formed into a convex shape of the plate-like workpiece. A first press molding step to be molded, and the convex portion molded in the first press molding step is press-molded in a direction opposite to the protruding direction, so that the convex portion is crushed and the convex top surface portion. And a second press molding step of displacing the convex side portions on both sides inward to form a closed cross section, and manufacturing a closed cross section member formed in a closed cross section from the plate-like workpiece A method for producing a closed cross-section member,
Before the second press molding step, further comprising a tab portion forming step of integrally forming a tab portion at an end portion in the longitudinal direction of the plate workpiece in the convex portion of the plate workpiece,
The second press molding step is performed by positioning the tab portion formed in the tab portion forming step with respect to a press mold that press-molds the convex portion in a direction opposite to the protruding direction thereof.
A method for producing a metal closed cross-section member. The press molding die includes a die that holds the plate-like workpiece, and a core die that press-molds the convex portion in a direction opposite to the protruding direction in a state where the plate-like workpiece is held on the die.
The second press molding step is performed by positioning the tab portion with respect to the die.
The manufacturing method of the metal closed cross-section member of Claim 1 characterized by the above-mentioned. A positioning hole is provided in the tab portion and a positioning pin is provided in the press mold,
The second press molding step is performed by positioning the tab portion with respect to the press mold by fitting the positioning hole to the positioning pin.
The manufacturing method of the metal closed cross-section member of Claim 1 or 2 characterized by the above-mentioned.   Between the first press molding step and the second press molding step, the end opposite to the convex top surface side of the convex side surface portion of the plate workpiece is directed inward of the plate workpiece. The method for manufacturing a metal closed cross-section member according to any one of claims 1 to 3, further comprising a bending step of bending.   After the second press molding step, the end portions of the convex side surface portions of the plate-like workpiece having a closed cross section are pressed against the surface portion opposite to the surface portion that presses the convex portion of the core mold. The manufacturing method of the metal closed cross-section member as described in any one of Claims 1-4 further equipped with the fixed-push-molding process which carries out and press-molds by contact.   6. A welding step of welding the end portions of the convex side surface portion of the plate-like workpiece having a closed cross section after the second press molding step is further provided. The manufacturing method of the metal closed cross-section member as described in any one of these.

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