JP2011073050A - Method for forming bent member, bent member, and method for manufacturing the same, - Google Patents

Abstract

The material is bent and deformed with almost no deformation of the drawing, overhanging, and extension flange, so that a single high-strength steel plate can be integrally pressed to a bent member. Furthermore, by reflecting the shape of the three-dimensional figure of the bending member that is the molding target in a plane, it is possible to easily obtain a member having a high bending strength and a complicated bending shape by reflecting the shape of the blank. The effect can be expected.
A blank 1 made of a single metal plate is formed into a three-dimensional bent member 30 in which a second wall portion 3 is connected to both sides of a first wall portion 2 that forms an inner peripheral side of a bending in a longitudinal direction. The bent member 30 is connected to the both ends of the constant-width chevron 4 and the constant-width chevron with the width direction of the first wall being the longitudinal direction of the first wall at the location of the longitudinal bend. A bending step of bending the blank so as to have a gradually changing valley-shaped portion 5 having a valley longitudinal direction.
[Selection] Figure 1

Description

  The present invention relates to a method of forming a flat plate into a bent member (specifically, a frame member having a bent shape), and in particular, enables forming a bent member from a high strength steel plate having a tensile strength (TS) of 590 MPa or more. The present invention relates to a forming method, a bent member, and a bent member manufacturing method.

  As a means for obtaining a bent member, conventionally, press molding (hereinafter, referred to as conventional press molding) in which various types of molding methods of drawing, stretching, stretching flange and bending are performed on a single metal plate is performed. Furthermore, a method of bending a cylindrical member (Patent Document 1), a roll forming technique (Patent Document 2), and a bending process using a hollow member (Patent Documents 3 and 4) have been proposed. As an example of reinforcing the bent member, a method of filling a foamed resin (Patent Document 5) has been proposed.

Japanese Patent Laid-Open No. 9-30345 Japanese Patent Application Laid-Open No. 11-129045 JP-A-8-174047 JP 2005-1490 A Japanese Patent Laid-Open No. 11-348813

  Increasing the strength of steel sheets in response to demands for weight reduction leads to a decrease in drawing, overhanging, and stretch flangeability of the steel sheets at the same time, so conventional press forming has problems such as cracks and wrinkles, especially complicated shapes. Accordingly, there has been a case where a bent member cannot be obtained. For example, when a single plate of a high strength steel plate having a TS of 590 MPa or more is formed into members 50A and 50B (having a curve in the XY plan view) constituting the bending member 50 as shown in FIG. Wrinkles (for example, occurring in “wrinkled” portions in the figure) and cracks in the side vertical wall portions and flange portions (for example, occurring in the “wrinkled” portions in the figure) will occur. At this time, it is possible to suppress the occurrence of cracks and wrinkles to some extent by optimizing the molding conditions such as wrinkle holding or changing the part shape. However, with such a method, TS to meet the need for weight reduction Therefore, it can be said that there is a limit to cope with further increase in strength of 980 MPa or more.

  In addition, a method for obtaining a high-strength bent member by bending a cylindrical member or roll forming is disclosed (Patent Documents 1 to 4), but from the viewpoint of process restrictions and material formability. In addition, it is difficult to obtain a complicated bent shape, and there are significant problems in production such as an increase in the number of processes. For example, when a low-strength material is used, a complicated shape can be easily obtained, but since the member strength is insufficient, there is a technique for obtaining a reinforcing effect by filling with a foamed resin (Patent Document 5). It is hard to say that the technology is always useful from the viewpoint of production or recycling.

  That is, in the conventional forming method, when a single sheet of high-strength steel plate is used as a raw material, it is difficult to form a desired bent member by integral press forming, or when a single plate of low-strength steel plate is used as a raw material, bending is performed. Although molding to a member is possible, there is a problem in that it is disadvantageous in terms of production and cost, such as an increase in component strength, because the strength of the member is insufficient.

The present invention for solving the above problems is as follows.
(Claim 1) A bending member forming method for forming a blank made of a single metal plate into a three-dimensional bending member in which a second wall portion is connected to both sides of a first wall portion that is an inner peripheral side of a bending in a longitudinal direction. ,
The bending member is connected to both ends of the constant-width chevron with the width direction of the first wall portion being the longitudinal direction of the first wall portion and the width direction of the second wall portion at the bent portion of the longitudinal direction. Or a valley portion having a gradual change width having a valley longitudinal direction, or a constant-width valley portion having a width direction of the first wall portion as a valley longitudinal direction, and both ends of the valley portion having the constant width. A bending member forming method, comprising: a bending step of bending the blank so as to have a gradually changing mountain shape having a width direction of the second wall portion as a mountain longitudinal direction.
(Claim 2) Before the bending step, at least a portion corresponding to the constant-width or gradually changing mountain-shaped portion and a portion corresponding to the constant-width or gradually changing valley-shaped portion with respect to the blank. The bending member forming according to claim 1, further comprising a preliminary step of making a crease and / or making a cut in the blank, wherein the bending is performed along the crease in the bending step. Method.
(Claim 3) A bending member manufactured by using the bending member forming method according to claim 1 or 2.
(Claim 4) A bending member manufacturing method, wherein a bending member is manufactured using the bending member molding method according to claim 1 or 2.

  According to the present invention, since the material undergoes bending deformation with almost no deformation of the drawing, overhanging, and extension flange, it is possible to perform integral press molding from a single sheet of high-strength steel sheet to a member constituting the bending member. . Furthermore, by reflecting a figure obtained by planarly developing a three-dimensional figure of a bending member as a forming target in a blank outline shape, it is possible to easily obtain a member having a high member strength and a complicated bending shape that has not been obtained conventionally. It is possible to expect a large weight reduction effect by expanding the space by reducing the cross section of the component, reducing the plate thickness, or eliminating the reinforcing member.

Schematic showing an example of an embodiment of the present invention ((a) a plan view of a blank, (b) a three-dimensional view of a bending member) Schematic showing one example of the embodiment of the present invention (an example different from the above-mentioned example) ((a) a plan view of a blank, (b) a three-dimensional view of a bent member) Schematic showing one example of the embodiment of the present invention (an example different from the above-mentioned example) ((a) a plan view of a blank, (b) a three-dimensional view of a bent member) Schematic showing one example of the embodiment of the present invention (an example different from the above-mentioned example) ((a) a plan view of a blank, (b) a three-dimensional view of a bent member) Schematic showing one example of the embodiment of the present invention (an example different from the above-mentioned example) ((a) a plan view of a blank, (b) a three-dimensional view of a bent member) Schematic showing one example of the embodiment of the present invention (an example different from the above-mentioned example) ((a) a plan view of a blank, (b) a three-dimensional view of a bent member) Schematic showing an example of how to crease Schematic showing an example of a bending member by conventional press molding

1 to 6 are schematic views ((a) a plan view of a blank and (b) a three-dimensional view of a bending member) showing different examples of embodiments of the present invention, respectively.
In the example of FIG. 1, the bending member 30 that is a forming target is bent at one location in the longitudinal direction, and the second wall portion 3 is connected to both sides of the first wall portion 2 that forms the inner peripheral side of the longitudinal bending. Has a shape.

  A bent portion at one place in the longitudinal direction of the bending member 30 includes a constant-width chevron 4 with the width direction of the first wall 2 as the longitudinal direction of the first wall 2, and a second wall connected to both ends of the constant-width chevron 4. There is a valley-shaped portion 5 having a gradually changing width in which the width direction of the portion 3 is the longitudinal direction of the valley. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. Corresponds to the corner line.

  By bending the blank 1 so that the portions of the mountain fold and valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, the material of the blank 1 is drawn and drawn. The bending member 30 which is a forming target is obtained by bending and deforming the projecting and extending flanges with little deformation. Such a bending process is realizable by bending the 2nd wall part 3 and the valley-shaped part 5, for example after bending the mountain-shaped part 4 by preforming.

In the example of FIG. 2, the bending member 30 that is a forming target is bent at one location in the longitudinal direction, and the second wall portion 3 is connected to both sides of the first wall portion 2 that forms the inner peripheral side of the longitudinal bending, Furthermore, it has a solid shape in which the flange 10 is connected to the end of the second wall 3 on the side opposite to the first wall 2 in the width direction. In addition, the cut | interruption 6 has entered into the longitudinal direction bending part of the flange 10. As shown in FIG.
A bent portion at one place in the longitudinal direction of the bending member 30 includes a constant-width chevron 4 with the width direction of the first wall 2 as the longitudinal direction of the first wall 2, and a second wall connected to both ends of the constant-width chevron 4. There is a valley-shaped portion 5 having a gradually changing width in which the width direction of the portion 3 is the longitudinal direction of the valley. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. Corresponding to the corner ridge line, the flange corresponding portion 10 </ b> A corresponds to the flange 10 of the bent member 30, and the cut 6 </ b> A corresponds to the cut 6 of the bent member 30.

  After the cut 6A is made in the blank 1, the blank 1 is bent so that the portions of the mountain fold and the valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, respectively. As a result, the material of the blank 1 is bent and deformed with little deformation of the squeezing, overhanging, and extension flange, and the bending member 30 that is a forming target is obtained. Such a bending process is realizable by bending the 2nd wall part 3 and the valley-shaped part 5, for example after bending the mountain-shaped part 4 by preforming.

In the example of FIG. 3, the bending member 30 that is a molding target is bent at one location in the longitudinal direction, and the second wall portion 3 is connected to both sides of the first wall portion 2 that forms the inner peripheral side of the longitudinal bending. Further, of the both sides, an end on the anti-first wall portion side in the width direction of the second wall portion 3 on one side and an end portion on the anti-first wall portion side in the width direction of the second wall portion 3 on the other side. It has a three-dimensional shape in which the third wall portion 11 is continuous on both sides.
A bent portion at one place in the longitudinal direction of the bending member 30 includes a constant-width chevron 4 with the width direction of the first wall 2 as the longitudinal direction of the first wall 2, and a second wall connected to both ends of the constant-width chevron 4. There is a valley-shaped portion 5 having a gradually changing width in which the width direction of the portion 3 is the longitudinal direction of the valley. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. The two third wall portion corresponding portions 11 </ b> A corresponding to the corner ridge lines and located at both ends in the width direction of the blank 1 correspond to the third wall portion 11 of the bending member 30.

  By bending the blank 1 so that the portions of the mountain fold and valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, the material of the blank 1 is drawn and drawn. The bending member 30 which is a forming target is obtained by bending and deforming the projecting and extending flanges with little deformation. Such a bending process is realizable by bending the 2nd wall part 3 and the valley-shaped part 5, for example after bending the mountain-shaped part 4 by preforming.

In addition, after the bending process, the two third wall corresponding portions 11A are in a separated state, but if necessary, their width direction free ends may be joined to form a closed cross section. . The joining method may be any of spot welding, continuous welding, rivet joining, and the like.
In the example of FIG. 4, the bending member 30 that is a molding target is bent at one location in the longitudinal direction, and the second wall portion 3 is connected to both sides of the first wall portion 2 that forms the inner peripheral side of the longitudinal bending, Further, of the both sides, an end on the anti-first wall portion side in the width direction of the second wall portion 3 on one side and an end portion on the anti-first wall portion side in the width direction of the second wall portion 3 on the other side. It has a three-dimensional shape in which the third wall portion 11 is continuous on both sides.

  A bent portion at one place in the longitudinal direction of the bending member 30 is connected to both ends of the valley portion 7 having a constant width with the width direction of the first wall portion 2 being the longitudinal direction of the valley, and both ends of the valley portion 7 having the constant width. There is a mountain-shaped portion 8 having a gradually changing width in which the width direction of the two wall portions 3 is the mountain longitudinal direction. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. The two third wall portion corresponding portions 11 </ b> A corresponding to the corner ridge lines and located at both ends in the width direction of the blank 1 correspond to the third wall portion 11 of the bending member 30.

  By bending the blank 1 so that the portions of the mountain fold and valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, the material of the blank 1 is drawn and drawn. The bending member 30 which is a forming target is obtained by bending and deforming the projecting and extending flanges with little deformation. Such bending can be realized, for example, by bending the valley portion 7 by preforming and then bending the second wall portion 3 and the mountain portion 8.

In addition, after the bending process, the two third wall corresponding portions 11A are in a separated state, but if necessary, their width direction free ends may be joined to form a closed cross section. . The joining method may be any of spot welding, continuous welding, rivet joining, and the like.
In the example of FIG. 5, the bending member 30 that is a forming target is bent at two places in the longitudinal direction, the bending direction is one direction, and both sides of the first wall portion 2 that forms the inner peripheral side of the bending in the longitudinal direction. The second wall portion 3 is connected to the second wall portion 3, and the end of the second wall portion 3 on the opposite side in the width direction of the second wall portion 3 on one side and the second width portion 3 on the opposite side of the second wall portion 3 on the other side. It has a three-dimensional shape in which the third wall portion 11 is continuous with both ends on the one wall portion side.

  In each bent portion at two places in the longitudinal direction of the bending member 30, it is connected to both ends of the valley portion 7 having a constant width with the width direction of the first wall portion 2 being the longitudinal direction of the valley, and both ends of the valley portion 7 having the constant width. There is a mountain-shaped portion 8 having a gradually changing width in which the width direction of the second wall portion 3 is the longitudinal direction of the mountain. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. The two third wall portion corresponding portions 11 </ b> A corresponding to the corner ridge lines and located at both ends in the width direction of the blank 1 correspond to the third wall portion 11 of the bending member 30.

  By bending the blank 1 so that the portions of the mountain fold and valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, the material of the blank 1 is drawn and drawn. The bending member 30 which is a forming target is obtained by bending and deforming the projecting and extending flanges with little deformation. Such bending can be realized, for example, by bending the valley portion 7 by preforming and then bending the second wall portion 3 and the mountain portion 8.

In addition, after the bending process, the two third wall corresponding portions 11A are in a separated state, but if necessary, their width direction free ends may be joined to form a closed cross section. . The joining method may be any of spot welding, continuous welding, rivet joining, and the like.
In the example of FIG. 6, the bending member 30 that is a forming target is bent at two places in the longitudinal direction, and the bending directions of one bending C1 and the other bending C2 are orthogonal to each other ( If C1 is a vertical curve, C2 is a horizontal curve). The bend of the bend C1, the second wall portion 3 ₁ contiguous with both sides of the first wall portion 2 ₁ forming the inner peripheral side of the bending C1, furthermore, the second wall portion 3 ₁ of the width direction of the one side of both sides the end of the reaction the first wall portion, the third wall portion 11 ₁ on both the ends of the anti-first wall portion of the other side the second wall portion 3 ₁ of the width direction are continuous in. Further, the bent portion of the bend C2, the first wall portion 2 ₂ forming the inner peripheral side of the bending C2 second wall portion 3 ₂ is contiguous to both sides, further, one side of both sides of the second wall portion 3 ₂ the end of the reaction the first wall portion side in the width direction, and both the third wall portion 11 ₂ is continuous to the end portion of the anti-first wall portion of the other side the second wall portion 3 ₂ in the width direction.

Then, since the direction of the bend at the bend C1 Tomo one point bending C2 of one point are orthogonal to each other, two of the second wall portion 3 ₂ of the first wall portion 2 ₁ a bending C2 of C1 bend one of the are the same and are identical to the first wall portion 2 ₂ bends C1 two second wall portion 3 one bend C2 of the _one and two second bend C1 the third wall portion 11 ₂ of the other one bend C2 of the walls 3 ₁ are the same and the third wall portion 11 of the bending C1 ₁ and bending two of the second wall portion 3 ₂ C2 Is the same as the other. The bending member 30 in the example of FIG. 6 has such a three-dimensional shape.

And in each bending part of the longitudinal direction two places of the bending member 30, the constant width valley-shaped part 7 which makes the width direction of the 1st wall part 2 (2 ₁ , 2 ₂ ) the valley longitudinal direction, and this constant width A mountain-shaped portion 8 having a gradual change width, which is continuous with both ends of the valley-shaped portion 7 and has the width direction of the second wall portion 3 (3 ₁ , 3 ₂ ) as a mountain longitudinal direction, exists. The plan view of the blank 1 corresponds to a plan development view of the bending member 30, and a mountain fold indicated by a dotted line in the plan view corresponds to a corner ridge line of the bending member 30, and a valley fold indicated by a broken line is the bending member 30. corresponding to the corner ridge, two third wall portion corresponding portion 11 1 _a located on the both widthwise end portions of the blank 1 corresponds to the third wall portion 11 ₁ of the bending C1 bending member 30, and the blank 1 the third wall portion corresponding portion 11 ₂ a adjacent the third wall portion corresponding portion 11 ₁ a corresponding to the third wall portion 11 ₂ of the bend C2 bending member 30.

  By bending the blank 1 so that the portions of the mountain fold and valley fold in the plan view of the blank 1 become the corner ridge line and the corner ridge line in the bent member 30 after forming, the material of the blank 1 is drawn and drawn. The bending member 30 which is a forming target is obtained by bending and deforming the projecting and extending flanges with little deformation. Such bending can be realized, for example, by bending the valley portion 7 by preforming and then bending the second wall portion 3 and the mountain portion 8.

In addition, after the bending process, the two third wall portion corresponding portions 11 ₁ A (corresponding to one of the two second wall portions 3 ₂ ) are in a separated state. Then, these width direction free ends may be joined to form a closed cross section. The joining method may be any of spot welding, continuous welding, rivet joining, and the like.
In the bending process according to the present invention, the material to be molded is deformed by the bending process so that the blank forming part of the blank becomes the corresponding bent part of the target member by using a mold, and the target material is deformed. Molded.

  Furthermore, in the present invention, in order to improve the positional accuracy of the bent portion during the bending process, it is preferable to crease the mountain fold and valley fold portions of the blank in advance. About a crease | fold, you may attach to all the object locations, and you may attach to a part and may raise the precision of a shape. Coining or the like can be preferably used as the processing method for forming the crease. Moreover, the method of transferring the uneven | corrugated shape given to the roll surface to the surface of material continuously is also mentioned. As a preferable form of such a fold, a V-groove as shown in FIG. 7 (d) is provided in the form of a line (a), a broken line (b), a dotted line (c), or a combination of these. Is mentioned. Here, the depth of the V-groove is preferably 20% or less of the metal plate thickness (abbreviated plate thickness). When the depth of the V-groove exceeds 20% of the plate thickness, there is a possibility of promoting a reduction in member strength required for an automobile frame member or the like, or cracking of a bent portion. This is because it is not easy to deepen the groove itself, and there are serious problems in production and cost.

Note that the shape of the groove is not limited to the V shape (not limited to the V groove illustrated in FIG. 7D), and may be various concave shapes such as a U shape. Moreover, when taking the curvature radius of a bending part large, you may provide a several groove | channel in parallel.
In addition, it is expected that there is a high risk of cracking or wrinkling due to local excessive elongation or shrinkage deformation processing during bending (for example, excessive elongation or shrinkage flange processing at the flange-corresponding portion of the blank). In the case where there are a plurality of local areas that are likely to be received, it is preferable to make a cut in such a local area in advance to prevent the occurrence of cracks or wrinkles more reliably.

  A blank made of a thin steel plate (material symbols A, B, C) having the thickness and tensile properties (yield strength YS, tensile strength TS, elongation El) shown in Table 1 is bent by the forming method shown in Table 2. The shape of the obtained bent member was visually observed to evaluate the forming method. As a result, as shown in Table 2, in the comparative example by the conventional press molding, wrinkles were generated in the “wrinkled” portion shown in FIG. Then, there was no generation of cracks and wrinkles, and a bent member almost according to the target shape was obtained.

  As shown in FIG. 7, a blank made of a thin steel plate (material symbols A, B, C) having the thickness and tensile properties (yield strength YS, tensile strength TS, elongation El) shown in Table 1 is preliminarily shown in FIG. After forming a crease composed of a straight, broken or dotted V-groove (the depth of the V-groove is shown in Table 3), it is formed into a bending member by the molding method shown in Table 3, and the obtained bending member The shape was visually observed to evaluate the molding method. As a result, as shown in Table 3, in the example of the present invention, cracks and wrinkles did not occur, and the degree of coincidence with the target shape was better than that of the example of the present invention in Example 1 (the dimensional accuracy was good). A bending member was obtained.

DESCRIPTION OF SYMBOLS 1 Blank 2, 2 ₁ , 2 ₂ 1st wall part 3, 3 ₁ , 3 ₂ 2nd wall part 4 Constant-width mountain-shaped part 5 Gradation-shaped valley-shaped part 6, 6A Break 7 Constant-width valley-shaped part 8 Slowly changing angle portion 10 Flange 10A Flange corresponding portion 11, 11 ₁ , 11 ₂ Third wall portion 11A, 11 ₁ A, 11 ₂ A Third wall corresponding portion 30 Bending member according to the present invention (molding target)
50 Bending member by conventional press molding (additional signs A and B are members constituting the bending member 50)

Claims (4)

It is a bending member forming method for forming a blank made of a single metal plate into a three-dimensional bending member in which the second wall portion is continuous on both sides of the first wall portion forming the inner peripheral side of the bending in the longitudinal direction,
The bending member is connected to both ends of the constant-width chevron with the width direction of the first wall portion being the longitudinal direction of the first wall portion and the width direction of the second wall portion at the bent portion of the longitudinal direction. Or a valley portion having a gradual change width having a valley longitudinal direction, or a constant-width valley portion having a width direction of the first wall portion as a valley longitudinal direction, and both ends of the valley portion having the constant width. A bending member forming method, comprising: a bending step of bending the blank so as to have a gradually changing mountain shape having a width direction of the second wall portion as a mountain longitudinal direction.   Before the bending step, crease at least a portion corresponding to the constant-width or gradual-change mountain portion and a portion corresponding to the constant-width or gradual-width valley portion with respect to the blank, and 2. The bending member forming method according to claim 1, further comprising a preliminary step of making a cut in the blank, wherein the bending process is performed along the crease in the bending step.   The bending member manufactured using the bending member shaping | molding method described in Claim 1 or 2.   A bending member manufacturing method, wherein the bending member is manufactured using the bending member forming method according to claim 1.

Images