Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/26—Deep-drawing for making peculiarly, e.g. irregularly, shaped articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/02—Stamping using rigid devices or tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/02—Stamping using rigid devices or tools
  • B21D22/06—Stamping using rigid devices or tools having relatively-movable die parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
  • B21D24/005—Multi-stage presses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/01—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D53/00—Making other particular articles
  • B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards

Definitions

• the present invention relates to a method of manufacturing a press-formed product including: a top plate portion and a vertical wall portion continuous from the top plate portion via a ridgeline portion, a step portion having a concave shape or a convex shape being formed in the top plate portion in a direction in which the ridgeline portion extends.
• Such a metal plate generates large stress generated at a press-forming time.
• large spring-back occurs and the metal plate tends to deviate from a target shape.
• spring-back occurs in which an inner angle formed by the top plate portion and the vertical wall portion is opened.
• Patent Literature 1 discloses a method of, in press-forming a product to a predetermined product size in two or more times of press-forming, in the last press-forming of the second and subsequent times, widening a punch width more than a punch width in the first press-forming.
• Patent Literature 2 discloses a method of press-forming a workpiece while pressing a die side pad against the workpiece in a state in which a punch side pad is projected further to the outer side than a pressurizing surface of a punch and press-forming the workpiece such that the punch side pad is at the same height as the pressurizing surface of the punch at a forming bottom dead center.
• the present invention has been made in view of the problems described above, and an object of the present invention is to provide a method of manufacturing a press-formed product that can reduce spring-back without spoiling the appearance of a press-formed product having a target shape in which a step portion having a concave shape or a convex shape is formed in a top plate portion.
• the press-formed product having a target shape, the press-formed product including the top plate portion and the vertical wall portion continuous from the top plate portion via the ridgeline portion, the step portion having the concave shape or the convex shape in the cross section orthogonal to the ridgeline portion being formed in the top plate portion in the extending direction of the ridgeline portion.
• the press-formed product including top plate portion in which the step portion having the concave shape or the convex shape is formed and the pair of vertical wall portions continuous from both the edges of the top plate portion via the ridgeline portion is divided by cutting the top plate portion in the direction in which the ridgeline portion extends.
• FIG. 12 illustrates an example of a press-formed product 100 targeted in the present invention.
• the press-formed product 100 has a hat cross-sectional shape including a top plate portion 101, a vertical wall portion 105 continuous from the top plate portion 101 via a ridgeline portion 103, and a flange portion 107 continuous from the vertical wall portion 105.
• a step portion 109 having a concave shape in a cross section orthogonal to the ridgeline portion is formed in an extending direction of the ridgeline portion 103 in top plate portion 101.
• the step portion 109 is formed over the entire length in the extending direction of the ridgeline portion 103.
• FIG. 3 illustrates an example of a method of press-forming the blank 110 into the press-formed product 100 ( FIG. 12 ) by a die 30.
• a process of press-forming the press-formed product 100 in one step of the related art is explained based on a cross-sectional view in a ridgeline portion orthogonal direction illustrated in FIG. 4 .
• the step portion 109 having the concave shape is formed in a part equivalent to the top plate portion 101 in a blank 110 ( FIG. 4(i) ) which is a metal plate ( FIG. 4(ii) ).
• both edge sides of the blank 110 are formed into the vertical wall portion 105 and the flange portion 107 ( FIG. 4(iii) to FIG. 4(v) ).
• FIG. 5(a) is a contour diagram in which a stress distribution on a plate thickness direction outer side is displayed in a perspective view of the press-formed product 100 having a target shape.
• FIG. 5(b) is a cross-sectional view in the ridgeline portion orthogonal direction in which the press-formed product 100 at the forming bottom dead center and the press-formed product 100 after being released and sprung back are superimposed and displayed.
• FIG. 5(a) illustrates stress in a direction orthogonal to the extending direction of the ridgeline portion 103.
• the inventor intensively studied a method of reducing such spring-back in the press-formed product 100.
• the order of press-forming is changed to form the step portion 109 in the top plate portion 101 after forming the ridgeline portion 103.
• the inventor conceived to draw the ridgeline portion 103 to the top plate portion 101 side, cause bending bending back in the part, and generate stress for offsetting the stress of the ridgeline portion 103 of the target shape.
• the present invention is based on such an idea and is specifically described in the following embodiments.
• a method of manufacturing a press-formed product according to a first embodiment of the present invention is a method of manufacturing the press-formed product 100 illustrated in FIG. 12 as an example. As illustrated in FIG. 1 , the method of manufacturing the press-formed product according to the first embodiment includes a first forming step and a second forming step. Each of the first forming step and the second forming step is explained below.
• the blank 110 is press-formed into the intermediate formed product 120 with a first die 10.
• the intermediate formed product 120 has a hat cross-sectional shape including an intermediate top plate portion 121, an intermediate ridgeline portion 123, an intermediate vertical wall portion 125, and an intermediate flange portion 127.
• the intermediate formed product 120 has a shape before the step portion 109 ( FIG. 2(b) ) is formed in the intermediate top plate portion 121.
• the second forming step is a step of forming the step portion 109 in the intermediate top plate portion 121 of the intermediate formed product 120 with a second die 20 and press-forming the press-formed product 100 having the target shape.
• the second forming step when the step portion 109 is formed, a part that has been the intermediate ridgeline portion 123 in the intermediate formed product 120 is drawn to the top plate portion 101 side, whereby bending back is caused in the part.
• the part drawn to the top plate portion 101 side is desirably the entire or a part of the part that has been the intermediate ridgeline portion 123 of the intermediate formed product 120.
• FIG. 6(a) is a contour diagram in which a stress distribution on a plate thickness direction outer side is displayed in a perspective view of the press-formed product 100 having the target shape.
• FIG. 6(b) is a cross-sectional view in a ridgeline portion orthogonal direction in which the press-formed product 100 at the forming bottom dead center and the press-formed product 100 after being released and sprung back are superimposed and displayed.
• FIG. 6(a) illustrates stress in a direction orthogonal to the extending direction of the ridgeline portion 103.
• FIG. 6(a) it can be seen that tensile stress is generated in the ridgeline portion orthogonal direction on the plate thickness direction outer side of the ridgeline portion 103 and compressive stress is generated on the top plate portion 101 side on the plate thickness direction outer side near the ridgeline portion 103.
• the tensile stress generated in the ridgeline portion 103 and the compressive stress generated in the top plate portion 101 are offset. Accordingly, spring-back does not occur even if the press-formed product 100 having the target shape is released.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 of the press-formed product 100 after the release is substantially the same as the inner angle at the forming bottom dead center.
• the first forming step as illustrated in a cross section in the ridgeline portion orthogonal direction in FIG. 7(a) , tensile stress due to bending is generated the plate thickness direction outer side in the intermediate ridgeline portion 123 and compressive stress is generated on the plate thickness direction inner side.
• the subsequent second forming step as illustrated in a cross section in the ridgeline portion orthogonal direction in FIG. 7(b) , when the step portion 109 is formed in the intermediate top plate portion 121, the part that has been the intermediate ridgeline portion 123 is drawn to the intermediate top plate portion 121 side from the intermediate vertical wall portion 125 side.
• the tensile stress on the plate thickness direction outer side of the ridgeline portion 103 is offset by the compressive stress ( FIG. 7(b) ) on the plate thickness direction outer side of the bent-back intermediate ridgeline portion 123 in the top plate portion 101.
• the compressive stress on the plate thickness direction inner side of the ridgeline portion 103 is offset by the tensile stress ( FIG. 7(b) ) on the plate thickness direction inner side of the bent-back intermediate ridgeline portion 123 in the top plate portion 101.
• stress acting on the ridgeline portion 103 is offset by stress generated by formation of the step portion 109. Therefore, spring-back sufficiently decreases.
• a cross-sectional line length of the intermediate formed product 120 is not set excessively larger than the target shape unlike the method disclosed in Patent Literature 2. Therefore, the ridgeline portion 103 is not bent. Moreover, since the cross-sectional line length of the intermediate formed product 120 is not set excessively smaller than the target shape, the angle of the ridgeline portion 103 can be set to the target shape.
• a low step portion having a step height smaller than the target shape may be formed in the intermediate top plate portion 121.
• the step portion 109 can be formed to suppress spring-back.
• a process of press-forming, in one step, the press-formed product 100 having a target shape in which the step portion 109 is formed in the top plate portion 101 is explained with reference to a cross-sectional view in a ridgeline portion orthogonal direction illustrated in FIG. 9 .
• the blank 110 is held by pads 59 and a punch 57 of a die 50 ( FIG. 9(i) ). Subsequently, both edge sides of the blank 110 are held and bent by cams 61 ( FIG. 9(ii) ).
• the vertical wall portion 105 and the flange portion 107 are formed and the step portion 109 is formed in the top plate portion 101 ( FIG. 9(iii) to FIG. 9(iv) ).
• the process of press-forming in one step, the press-formed product 100 having the target shape is analyzed by the finite element method (FEM) and a stress distribution at a forming bottom dead center is illustrated in FIG. 10 .
• FEM finite element method
• FIG. 10(a) is a contour diagram in which a stress distribution on a plate thickness direction outer side is displayed in a perspective view of the press-formed product 100.
• FIG. 10(b) is a cross-sectional view in the ridgeline portion orthogonal direction in the press-forming process.
• FIG. 10(a) illustrates stress in a direction orthogonal to the extending direction of the ridgeline portion 103.
• tensile stress is generated on the plate thickness direction outer side of the ridgeline portion 103 and the vicinity of the ridgeline portion 103 and compressive stress is generated on the top plate portion 101 side adjacent to the ridgeline portion 103.
• FIG. 10(b) these stresses offset each other and spring-back does not occur.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 of the press-formed product 100 is substantially the same as the inner angle at the forming bottom dead center.
• the tensile stress on the plate thickness direction outer side of the ridgeline portion 103 is offset by the compressive stress ( FIG. 7(b) ) on the plate thickness direction outer side of the bent-back ridgeline portion 103 in the top plate portion 101.
• the compressive stress ( FIG. 7(a) ) on the plate thickness direction inner side of the ridgeline portion 103 is offset by the tensile stress ( FIG. 7(b) ) on the plate thickness direction inner side of the ridgeline portion 103 unbent in the top plate portion 101. Accordingly, in the press-formed product 100 having the target shape after being released, spring-back sufficiently decreases.
• the method of manufacturing the press-formed product according to the second embodiment it is possible to sufficiently reduce spring-back in which the inner angle between the top plate portion 101 and the vertical wall portion 105 is opened in the press-formed product 100 in which the step portion 109 having the concave shape is formed. Furthermore, the method of manufacturing the press-formed product according to the second embodiment does not deteriorate the appearance of the press-formed product 100 having the target shape as in the first embodiment explained above.
• the step portion 109 may be formed immediately before the forming of the ridgeline portion 103 is completed or the step portion 109 may be formed after the forming of the ridgeline portion 103 is completed.
• a step height (depth to the bottom surface of the step portion) of the step portion having the concave shape formed in the top plate portion is preferably set in a range of 1/5 to two times a cross-sectional length in the ridgeline portion orthogonal direction.
• the cross-sectional length in the ridgeline portion orthogonal direction refers to length from a bending start part with the top plate portion to a bending stop part with the vertical wall portion in the ridgeline portion.
• step height of the step portion is as excessively small as 1/5 or less of the cross-sectional length in the ridgeline portion orthogonal direction, an amount of drawing in and bending back the vertical wall portion when forming the step portion deceases. Expansion of the inner angle between the top plate portion and the vertical wall portion due to spring-back after release cannot be sufficiently offset.
• step height of the step portion is as excessively large as exceeding two times of the cross-sectional length in the ridgeline portion orthogonal direction, an amount of drawing the vertical wall portion 105 when forming the step portion is too large and the vertical wall portion is draw-formed to cause warpage. Therefore, the press-formed product 100 less easily formed in the target shape.
• Both of the first and second embodiments target a press-formed product in which a step portion recessed in a press-forming direction is formed.
• the present invention may target a press-formed product in which a step portion having a convex shape in a cross section orthogonal to the ridgeline portion is formed in a top plate portion in an extending direction of a ridgeline portion.
• the step portion having the convex shape only has to be formed by the same method as the method in the first or second embodiment.
• a material is drawn from the vertical wall portion toward the top plate portion side when the step portion having the convex shape is formed.
• bending-back occurs a part that has been the intermediate ridgeline portion.
• the present invention can reduce spring-back in which the inner angle between the top plate portion and the vertical wall portion is opened not only in the press-formed product having the hat cross-sectional shape but also in a press-formed product having a U cross-sectional shape, a Z cross-sectional shape, or an L cross-sectional shape.
• the press-formed product having the Z cross-sectional shape and including the top plate portion, the vertical wall portion, and the flange portion can be manufactured by a press-forming step and a dividing step as explained below.
• the press-forming step is a step of press-forming the press-formed product 100 having the hat cross-sectional shape illustrated in FIG. 12 by the method according to the first or second embodiment explained above.
• the dividing step is a step of cutting the top plate portion 101 of the press-formed product 100 in the extending direction of the ridgeline portion and dividing the press-formed product 100. Accordingly, two press-formed products having the Z cross-sectional shape can be obtained.
• spring-back can be reduced as explained above. For that reason, in the press-formed product having the Z cross-sectional shape obtained by dividing the press-formed product having the hat cross-sectional shape in the subsequent dividing step, spring-back is sufficiently reduced. As explained above, two press-formed products having the Z cross-sectional shape with reduced spring-back can be obtained from the press-formed product having the hat cross-sectional shape manufactured by one press-forming. This is preferable because production cost can be reduced.
• the press-formed product having the U cross-sectional shape may be press-formed and the top plate portion may be cut in the subsequent dividing step to be divided into two press-formed products having the L cross-sectional shape.
• a steel sheet having a plate thickness of 1.0 mm and tensile strength of a 1470 MPa class or a 980 MPa class was used to manufacture press-formed products having a hat cross-sectional shape, a U cross-sectional shape, a Z cross-sectional shape, and an L cross-sectional shape.
• the width of the top plate portion 101 was set to 150 mm
• the vertical wall height of the vertical wall portion 105 was set to 55 mm
• the inner angle between the vertical wall portion and the top plate portion was set to 95°
• the bending radiuses of the ridgeline portion 103 and the step portion 109 were respectively set to R 4 mm on the inside of bending.
• the width of the step portion 109 was set to 80 mm and the step height of the step portion 109 was set to 9 mm (1.4 times the cross-sectional length in the ridgeline portion orthogonal direction).
• the step height of a step portion having a shallow concave shape and a shallow convex shape (hereinafter referred to as low step portion) was set to 5 mm.
• the press-formed product having the U cross-sectional shape is obtained by removing the flange portion 107 from the press-formed product 100 having the hat cross-sectional shape illustrated in FIG. 11 .
• Dimensions of the parts were set equal to the dimensions of the press-formed product 100 illustrated in FIG. 11 .
• the press-formed product having the Z cross-sectional shape is obtained by removing the vertical wall portion 105 and the flange portion 107 on one side from the press-formed product 100 having the hat cross-sectional shape illustrated in FIG. 11 . Then, the widths of the top plate portion and the step portion were respectively set to 75 mm and 40 mm, which were halves of the widths in the press-formed product 100 and the dimensions of the other parts were set equal to the dimensions of the press-formed product 100.
• the press-formed product having the L cross-sectional shape is obtained by removing the vertical wall portion 105 on one side and the flange portions 107 on both sides from the press-formed product 100 having the hat cross-sectional shape illustrated in FIG. 11 .
• the widths of the top plate portion and the step portion were set to halves of the widths in the press-formed product 100 and the dimensions of the other parts were set equal to the dimensions of the press-formed product 100.
• the press-formed products press-formed by the methods explained in the first and second embodiments explained above were inventive examples.
• the shape of the step portion formed in the top plate portion in the target shape explained above, the number of steps, and timing for forming the step portion in the top plate portion were changed.
• the number of steps of the press-formed product was set to two as the method according to the first embodiment explained above and was set to one as the method according to the second embodiment explained above.
• press-forming was performed in one step of the related art and the step portion 109 having the concave shape was formed from an initial stage of forming.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 1 was 111 degrees, and spring-back greatly occurred.
• press-forming was performed in one step according to the present invention and the step portion 109 having the concave shape was formed near the forming bottom dead center.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 2 was 102 degrees and spring-back satisfactorily decreased more than the spring-back in No. 1 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and the step portion 109 having the concave shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 3 was 100 degrees and spring-back satisfactorily deceased more than the spring-back in No. 1 of conventional example and No. 2 of the invention example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion having a shallow concave shape was formed in the first forming step and was set to a step height of the target shape in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 4 was 101 degrees and spring-back satisfactorily decreased more than the spring-back in No. 1 of conventional example.
• press-forming was performed in one step of the related art and a step portion having a concave shape was formed from the initial stage of forming.
• the inner angle between the top plate portion and the vertical wall portion in No. 5 was 108 degrees and spring-back greatly occurred.
• press-forming was performed in one step according to the present invention and a step portion having a concave shape was formed near the forming bottom dead center.
• the inner angle between the top plate portion and the vertical wall portion in No. 6 was 98 degrees and spring-back satisfactorily decreased more than the spring-back in No. 5 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a concave shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 7 was 98 degrees and, as in No. 6 of the invention example, spring-back satisfactorily decreased more than No. 5 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion having a shallow concave shape was formed in the first forming step and set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 8 was 99 degrees and spring-back satisfactorily decreased more than the spring-back in No. 5 of conventional example.
• press-forming was performed in one step of the related art and a step portion having a convex shape was formed from the initial stage of forming.
• the inner angle between the top plate portion and the vertical wall portion in No. 9 was 115 degrees and spring-back greatly occurred.
• press-forming was performed in one step according to the present invention and a step portion having a convex shape was formed near the forming bottom dead center.
• the inner angle between the top plate portion and the vertical wall portion in No. 10 was 101 degrees and spring-back satisfactorily decreased more than the spring-back in No. 9 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 11 was 101 degrees and, as in No. 10, spring-back satisfactorily deceases more than the spring-back in No. 9 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion having a low convex shape was formed in the first forming step and was set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 12 was 104 degrees and spring-back satisfactorily decreased more than the spring-back in No. 9 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 15 was 101 degrees and, as in No. 14 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 13 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion having a convex shape was formed in the first forming step and set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 16 was 101 degrees and, as in No. 14 and No. 15 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 13 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a concave shape was formed in the top plate portion in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 20 was 100 degrees and spring-back satisfactorily decreased more than the spring-back in No. 17 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the top plate portion in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 21 was 101 degrees and, as in No. 19 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 17 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a concave shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 25 was 98 degrees and, as in No. 23 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 22 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 26 was 101 degrees and, as in to No. 24 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 22 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and the step portion 109 having the concave shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 53 was 97 degrees and spring-back satisfactorily decreased more than the spring-back in No. 51 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion was formed in the first forming step and set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 54 was 97 degrees and, as in No. 53 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 51 of conventional example.
• press-forming was performed in two steps including a first forming step and a second forming step according to the present invention and a step portion having a concave shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 57 was 96 degrees and, as in No. 56 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 55 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion was formed in the first forming step and the low step portion was set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 58 was 96 degrees and, as in No. 56 and No. 57 of the invention example, spring-back satisfactorily decreased more than the step-back in No. 55 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion 101 and the vertical wall portion 105 in No. 61 was 98 degrees and spring-back satisfactorily decreased more than the spring-back in No. 59 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion was formed in the first forming step and a step portion was formed with height set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 62 was 99 degrees and spring-back satisfactorily decreased more than the spring-back in No. 59 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 65 was 98 degrees and spring-back satisfactorily decreased more than the spring-back in No. 63 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a low step portion is formed in the first forming step and a step portion is formed with height set to the step height of the target shape in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 66 was 99 degrees and, as in No. 64 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 63 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a concave shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 70 was 97 degrees and spring-back satisfactorily decreased more than the spring-back in No. 67 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 71 was 99 degrees and spring-back satisfactorily decreased more than the spring-back in No. 67 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a concave shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 75 was 96 degrees and, as in 73 of the invention example, spring-back satisfactorily decreased more than the spring-back in No. 72 of conventional example.
• press-forming was performed in two steps including the first forming step and the second forming step according to the present invention and a step portion having a convex shape was formed in the second forming step.
• the inner angle between the top plate portion and the vertical wall portion in No. 76 was 98 degrees and spring-back satisfactorily decreased more than the spring-back in No. 72 of conventional example.
• the present invention can provide a method of manufacturing a press-formed product that can reduce spring-back without spoiling the appearance of a press-formed product having a target shape in which a step portion having a concave shape or a convex shape is formed in a top plate portion.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

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• 2022
  • 2022-11-14 JP JP2022181604A patent/JP2024070951A/ja active Pending
• 2023
  • 2023-08-23 EP EP23891116.8A patent/EP4596134A4/fr active Pending
  • 2023-08-23 CN CN202380078748.0A patent/CN120129576A/zh active Pending
  • 2023-08-23 WO PCT/JP2023/030319 patent/WO2024105956A1/fr not_active Ceased
  • 2023-08-23 KR KR1020257013659A patent/KR20250076609A/ko active Pending
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