WO2013153680A1

WO2013153680A1 - Device and method for producing closed-cross-section-structure component having curved shape

Info

Publication number: WO2013153680A1
Application number: PCT/JP2012/060639
Authority: WO
Inventors: 和彦樋貝; 雄司山▲崎▼; 新宮　豊久
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2012-04-13
Filing date: 2012-04-13
Publication date: 2013-10-17

Abstract

The present invention provides a device and method for producing, from two metal plates, a closed-cross-section-structure component having a deformed cross-sectional shape having a welded section and a bend in the direction of component length. In conventional techniques, it is not possible to simultaneously proceed with bending and cross-section deformation. The present invention can simultaneously proceed with bending and cross-section deformation. Two metal sheets (1a, 1b) that are provided with a sheet-length-direction bend corresponding to a component (10) length-direction bend and that have both sheet width edges matched at a flange section (13) are press-molded in a manner so that creases (2) are imparted to sheet sections corresponding to a non-welded bent section (12) and a welded section (11) within the component cross section, then are overlapped vertically in a manner so that the protruding surface sides thereof are at the outside and the creases of flange-section-corresponding sites facing each other vertically at the left and right edges of the width thereof are welded in the lengthwise direction thereof, forming the welded section (11), and while guiding and conveying the obtained closed-cross-section structure (5) by means of a left-right pair of rotating rollers (40a, 40b) or furthermore by a lower rotating roller (40c), with the creases and the welded sections as starting points, the closed-cross-section structure is caused to become 3D and forms a component having a target shape by means of altering the inter-roller gap of the rotating rollers or by furthermore raising/lowering the rotating roller.

Description

Method and apparatus for manufacturing a closed cross-section structure part having a bent shape

The present invention relates to a method and an apparatus for manufacturing a closed cross-section structure part having a bent shape, and in particular, in the conventional automobile, home appliance, and other fields, it is manufactured by joining two separately formed bodies to form a closed cross section. The present invention relates to a method and an apparatus for manufacturing a closed cross-section structure part having a bent shape, which can advantageously give a bent shape for the purpose of weight reduction, impact characteristics, and improvement of rigidity performance and an irregular cross-sectional shape over the entire length of the part.

In Patent Document 1, a high-tensile steel sheet is roll-formed to produce a formed body having a constant cross-sectional shape, and then the formed body is induction-hardened and further has a constant curvature in its longitudinal direction (direction perpendicular to the cross-section). As described above, a technique for manufacturing a bumper reinforcement as a shock absorber for a vehicle by bending into a circular arc shape (sweep molding) is described.

Patent Document 2 is provided with a pair of rotating rolls arranged so as to sandwich the conveyance path of the thin metal plate and a rotating roll arranged below the pair of rotating rolls, and the pair of rotating rolls is variable in the roll interval. As a roll forming apparatus that can move up and down the disposed rotating rolls, and a part manufacturing method in the apparatus, when a part of a long thin metal plate is conveyed between the pair of rotating rolls, A technique for manufacturing a roll-formed part that does not have the same cross section in the longitudinal direction by changing the roll interval and raising and lowering a rotating roll installed below so as to locally deform the metal sheet being conveyed. Is described.

JP 2008-120227 A Japanese Patent Laid-Open No. 2007-30023

In the technique of Patent Document 1, a closed cross-section part having a constant cross-sectional shape is formed by general roll forming, and then induction-quenched, and further, a curvature is given by three bending pieces to produce a bent closed cross-section part. . However, it is impossible to mold a part whose sectional shape in the longitudinal direction of the part is not constant. Further, the curvature applying direction is limited only to the two-dimensional direction.

In addition to the general roll forming having a pair of rotating rolls, the technology of Patent Document 2 uses a forming apparatus with a rotating roll for changing the cross-sectional shape in the longitudinal direction of the part below the pair of rotating rolls. Although it is a molding technique that makes it possible to change the cross-sectional shape in the longitudinal direction, it is impossible to impart a curved shape in the longitudinal direction at the same time.

As described above, in the conventional technique, the cross-sectional shape (specifically, the cross-sectional shape perpendicular to the component longitudinal direction, that is, the cross-sectional shape of the component short direction) is changed in the component longitudinal direction, and the bending in the component longitudinal direction ( Or, furthermore, the three-dimensional shape imparting torsion) was impossible to proceed at the same time, so the cross-section of each part and the three-dimensional shape impartation had to be made into separate molding processes, It was costing minutes. In addition, when a high-strength steel plate is used as a material for weight reduction, molding defects are likely to occur in bending after the cross-section of each part of the part is deformed.

The inventors have intensively studied to solve the above-mentioned problems, and as a result, a closed cross-section structural part having a modified cross-sectional shape having a bend in the longitudinal direction of the part from two metal plates can be obtained by deforming each cross-section of the part. In the molding process in which the three-dimensional shape formation proceeds simultaneously, a means that can be manufactured was found and the present invention was made.

That is, the present invention is as follows.
(1) A method of manufacturing a closed cross-section structure part having a deformed cross-sectional shape in which a bent part and a welded part are bent from two metal plates in a longitudinal direction of the part, and a flange part is connected to the welded part.
A plate corresponding to a non-weld bent portion and a welded portion in the cross section of the component is provided by providing two metal plates each having a plate longitudinal direction curve corresponding to the component longitudinal direction curve and corresponding to both ends of the plate width to the flange portion. A first step of press molding so that a crease is attached to the site;
The two metal plates after the press forming are overlapped vertically so that the convex side is on the outside, and the folds of the flange corresponding parts are welded in the longitudinal direction facing each other on both the left and right sides of the width. Forming a welded portion to form a closed cross-section structure,
The obtained closed cross-section structure is guided and transported by a pair of left and right rotating rolls or further lower rotating rolls, and the folds and the folds are changed by changing the roll interval of the rotating rolls or raising and lowering the rotating rolls. And a third step of forming a three-dimensional object with a welded portion as a starting point to form a part having a target shape.

(2) An apparatus for manufacturing a closed cross-section structure part having a modified cross-sectional shape having a bent portion and a welded portion in the longitudinal direction of the component from two metal plates, and a flange portion connected to the welded portion,
A plate corresponding to a non-weld bent portion and a welded portion in the cross section of the component is provided by providing two metal plates each having a plate longitudinal direction curve corresponding to the component longitudinal direction curve and corresponding to both ends of the plate width to the flange portion. A press molding machine that performs press molding so that a crease is attached to the site;
The two metal plates after the press forming are overlapped vertically so that the convex side is on the outside, and the folds of the flange corresponding parts are welded in the longitudinal direction facing each other on both the left and right sides of the width. A welder that forms a closed section structure by forming a welded portion,
The obtained closed cross-section structure is guided and transported by a pair of left and right rotating rolls or further lower rotating rolls, and the folds and the folds are changed by changing the roll interval of the rotating rolls or raising and lowering the rotating rolls. An apparatus for manufacturing a closed cross-section structure part, comprising: a roll forming machine that forms a three-dimensional object from a welded part as a starting part.

According to the present invention, it is possible to impart a bending in the longitudinal direction of a part and its vertical direction, that is, a three-dimensional shape, by changing the cross-sectional shape, and manufacturing by reducing the number of molds and the assembly process. The cost can be greatly reduced by the effect of process simplification.
Furthermore, since it is possible to obtain a predetermined shape mainly by bending, it is easy to manufacture parts using ultra-high strength steel sheets.

It is explanatory drawing about the manufacturing process which concerns on this invention. It is a schematic three-dimensional view which shows an example of the target shape of components. It is the schematic which shows the components manufacture point of an Example and a comparative example. It is explanatory drawing about the manufacturing process of hexagonal cross-section components. It is a schematic solid figure which shows an example of the target shape of a hexagonal cross-section component. It is the schematic which shows the manufacture point of a hexagonal cross-section component.

FIG. 2 is a schematic three-dimensional view showing an example of a part (a closed cross-section structure part having a curved shape) 10 to be manufactured by the present invention.
In the example of FIG. 2, the cross-sectional shape (meaning the cross-sectional shape in the short direction, hereinafter the same) is a quadrangle and has a bend in the longitudinal direction, and the cross-sectional shape is different at the start and end portions in the longitudinal direction. (Ie, it is a variant). The side length of the start end of the rectangular cross section is 30 mm, the length of one end of the end is 20 mm, the total length in the longitudinal direction (shortest distance between both ends in the length direction) is 300 mm, the curvature radius of the bend is 400 mm at the start end, and 400 mm at the end. It is a shape in which the direction of bending is reversed left and right at the center in the longitudinal direction of the part (position 150 mm from both ends in the longitudinal direction). In addition, a pair of two vertices at diagonal positions of the quadrangle form a welded portion 11 and the other pair forms a non-welded bent portion 12. A flange portion 13 is connected to the welded portion 11. The width of the flange portion 13 is 5 mm.

FIG. 1 is an explanatory view of a manufacturing process according to the present invention. Here, a case where the component of FIG. 2 is manufactured will be described as an example. The part in the example of FIG. 2 is the part of Example 1 shown in FIG.
In FIG. 3, the two

metal plates

1 a and 1 b have 2 on the width end side corresponding to the welded portion 11 connected to the flange portion 13 of the component 10 in order to represent the plate longitudinal direction bending corresponding to the component longitudinal direction bending. As the bending lines of the book, bending lines (B) and (B) are provided in the metal plate 1a, and bending lines (B ') and (B') are provided in the metal plate 1b, respectively, and the width corresponding to the non-weld bent portion 12 is provided. As one inner bending line, a bending line (A) is provided in the metal plate 1a, and a bending line (A ') is provided in the metal plate 1b.

(First step)
The first step is a preforming step. Using a press molding machine 20 having a punch 3 and a die 4, a bending line (A) (A ') on the inner side of the width corresponding to the non-weld bent portion 12 among the four vertices of the component square cross section with respect to the metal plate 1 And the part of the bending line (B) (B ′) on the width end side corresponding to the welded part 11 are press-molded so that the crease 2 is attached. The mold shapes of the punch 3 and the die 4 are designed so that the crease 2 is formed. The radius of curvature in the plate width direction at the location of the crease 2 takes a constant value over the entire length of the plate for each crease 2.

(Second step)
The second step is a width end welding step. The

pre-formed metal plates

1a and 1b are overlapped and welded so that the projecting side (the side where the crease 2 is formed by bending in the first step is the convex surface) is the outside. The left and right bending lines (B) of the width overlapped with the upper and lower

pressing jigs

6a and 6b, which are arranged in the machine 30 and pressed by the upper and lower

pressing jigs

6a and 6b, respectively, facing the upper and lower sides of the width. B ′) folds 2 in the part and folds 2 in the bending line (B) (B ′) part on the right end are welded in the longitudinal direction to form a welded portion 11 to form a closed cross-section structure 5. This welding is preferably performed by spot welding or laser welding. A well-known spot welding apparatus, a laser welding apparatus, etc. can be used for a welding apparatus (not shown).

(Third step)
The third step is a roll forming step. That is, the closed cross-section structure 5 obtained in the previous step is passed through the roll forming machine 40. The roll forming machine 40 changes the roll interval between the

rotating rolls

40a and 40b while guiding and transporting the closed cross-section structure 5 with a pair of left and right

rotating rolls

40a and 40b, or a rotating roll 40c below. Furthermore, by raising and lowering the rotary roll 40c, the fold 2 and the welded portion 11 are used as a starting point to form a part 10 having a target shape.

The shape of the rotating roll is set to a shape that can stably guide the roll contact portion of the closed cross-section structure, which is the workpiece, without causing a positional shift or the like. The rotary rolls 40a, 40b, and 40c in FIG. 1 are V-shaped as an example, but are not limited thereto. In particular, the rotary rolls 40a and 40b that guide the flange portion 13 are provided with a notch 14 for flange guide at the bottom. The roll interval of the rotating roll (corresponding to the pressing force from the left and right by the roll to the closed cross-section structure) and the raising and lowering position of the rotating roll (corresponding to the pushing force from the lower side by the roll to the closed cross-section structure) are obtained by the target part shape. To change. How to make the change can be obtained in advance by theoretical analysis or experiment. Further, a rotating roll corresponding to the lower rotating roll may be installed on the upper side and used to form the target shape of the component.

In this example, since the target shape of the part is a shape without twisting, in order to achieve the shape, two metal plates 1 on each of the two metal plates 1 in FIG. Regarding the total three bend lines including the bend line and one bend line inside the width, the radius of curvature is the same and the center of curvature is placed on the same straight line, but the target shape of the part is a twisted shape. In this case, with respect to the three bending lines in total, the target shape having a twist is achieved by either changing the radius of curvature or by preventing the center of curvature from being placed on the same straight line or both. Is possible. For shapes other than a quadrangle, the first to third steps can produce a closed cross-section structure part using a mold, a rotating roll, etc. having a shape corresponding to the part shape, as in the case of a square part. it can.

For example, when a hexagonal cross-section component as shown in FIG. 5 is a manufacturing target, the number of non-weld bent portions 12 is increased by two compared to the case of the square cross-section of FIG. Accordingly, in accordance with this, as shown in FIG. 6, four bending lines (A), (B), (A ′) and (B ′) on the inner side are set for each of the upper and lower blanks.
Then, as a manufacturing process, for example, a process as shown in FIG. 4 is adopted in which the apparatus member used in FIG. 1 is changed in response to the change from the rectangular cross section to the hexagonal cross section. That is, the mold shape used in the first step (pre-molding step) is a mold shape in which the crease 2 is attached at the positions of the bending lines (A), (B), (A ′), and (B ′) in FIG. To do. In the second step (flange portion welding step), the holding jig 6 has a cross-sectional shape that matches the blank shape after preforming. In the third step (roll forming step), the roll profile of the lower rotating roll 40c is formed into a flat bottom shape that can stably guide one side of the hexagon, for example. Except for these changes, the configuration is the same as in FIG. Thereby, the post-molding shape shown in the lower side of FIG. 6 is achieved with high accuracy and ease.

In the examples, the following items are common items.
[Part Target Shape] The cross section is a shape that is irregularly shaped in the longitudinal direction of the part (each corner is a right angle), has a flange portion that continues to the welded portion, and has an S-shaped bend in the longitudinal direction of the component.
[Raw metal plate] Two blanks A and B having an S-shaped bend corresponding to the part target shape were cut out from a cold-rolled steel plate (1.4 mm thick) having a tensile strength of 1180 MPa as a material.
[Welding conditions] Laser welding, laser output 3.8 kW, welding speed 2.5 m / min, laser focus diameter 2 mm

Example 1
As shown in FIG. 3 (a), one blank 1a (blank A) has a bend line to be a crease 2 at a center position between two bend lines (B) and (B) on the width end side. (A) is set, and the other blank 1b (blank B) is a bending line to be the crease 2 at the center position between the two bending lines (B ′) and (B ′) on the width end side. (A ') was set. These two blanks A and B are preformed as described above in the first step, and the creases 2 along the bending lines (A), (A ′), (B), and (B ′) are attached respectively, and the second step. As described above, the blank A is the upper side, the blank B is the lower side, and the bending line (B) (B ') portion on the width end side facing up and down is laser-welded, and the obtained closed cross-section structure 5 was roll-formed as described above in the third step to obtain a part 10.

(Example 2)
As shown in FIG. 3 (b), one blank 1a (blank A) should become a crease 2 at a position to the left of the center between the two bending lines (B) and (B) on the width end side. The bend line (A) is set, and the other blank 1b (blank B) is positioned to the right of the center between the two bend lines (B ′) (B ′) on the width end side (the above-mentioned position with respect to the center position). A bending line (A ′) to be the crease 2 is set at a position symmetrical to the left side position. These two blanks A and B are preformed as described above in the first step, and the creases 2 along the bending lines (A), (A ′), (B), and (B ′) are attached respectively, and the second step. As described above, the blank A is the upper side, the blank B is the lower side, and the bending line (B) (B ') portion on the width end side facing up and down is laser-welded, and the obtained closed cross-section structure 5 was roll-formed as described above in the third step to obtain a part 10.

(Comparative example)
Using a single blank cut out from the same steel plate as in the example in a shape different from that in the example, the forming process is performed so that the forming start part and the forming end part have an irregular cross-sectional shape by roll forming as usual ( 3), the intermediate shape part 15 was formed, and this was bent in a three-point bending manner by roll forming to obtain a final shape part 16.

The moldability was evaluated for the examples and comparative examples. As a result, in any of the embodiments, the molding can be performed in all of the first to third steps, and the part 10 after the third step achieves the target shape and molding such as fracture, buckling, wrinkle, etc. There were no defects. On the other hand, in the comparative example, the intermediate shape part 15 after the irregular cross section did not have a molding defect occurrence place, but the final shape part 16 after the bending process was buckled at the shown position.

1 Metal plate (a and b are either one of the two and the other, also called blank)
2 Fold line (corresponding to bending line (A) (A '), (B) (B'))
3 Punch 4 Die 5 Closed section structure 6 Holding jig (a and b are upper and lower)
10 parts (closed cross-section structure parts having a bent shape to be manufactured by the present invention)
DESCRIPTION OF SYMBOLS 11 Welding part 12 Non-weld bending part 13 Flange part 14 Notch 15 Intermediate shape part 16 of comparative example 16 Final shape part 20 of comparative example Press molding machine 30 Welding machine 40

Roll forming machine

40a, 40b Rotary roll 40c Rotary roll

Claims

A method for producing a closed cross-section structure part having an irregular cross-sectional shape having a bent portion and a welded portion in a longitudinal direction of a component from two metal plates, and a flange portion connected to the welded portion,
A plate corresponding to a non-weld bent portion and a welded portion in the cross section of the component is provided by providing two metal plates each having a plate longitudinal direction curve corresponding to the component longitudinal direction curve and corresponding to both ends of the plate width to the flange portion. A first step of press molding so that a crease is attached to the site;
The two metal plates after the press forming are overlapped vertically so that the convex side is on the outside, and the folds of the flange corresponding parts are welded in the longitudinal direction facing each other on both the left and right sides of the width. Forming a welded portion to form a closed cross-section structure,
The obtained closed cross-section structure is guided and transported by a pair of left and right rotating rolls or further lower rotating rolls, and the folds and the folds are changed by changing the roll interval of the rotating rolls or raising and lowering the rotating rolls. And a third step of forming a three-dimensional object with a welded portion as a starting point to form a part having a target shape.
An apparatus for manufacturing a closed cross-section structure part having a modified cross-sectional shape having a bent portion and a welded portion in the longitudinal direction of a component from two metal plates, and a flange portion connected to the welded portion,
A plate corresponding to a non-weld bent portion and a welded portion in the cross section of the component is provided by providing two metal plates each having a plate longitudinal direction curve corresponding to the component longitudinal direction curve and corresponding to both ends of the plate width to the flange portion. A press molding machine that performs press molding so that a crease is attached to the site;
The two metal plates after the press forming are overlapped vertically so that the convex side is on the outside, and the folds of the flange corresponding parts are welded in the longitudinal direction facing each other on both the left and right sides of the width. A welder that forms a closed section structure by forming a welded portion,
The obtained closed cross-section structure is guided and transported by a pair of left and right rotating rolls or further lower rotating rolls, and the folds and the folds are changed by changing the roll interval of the rotating rolls or raising and lowering the rotating rolls. An apparatus for manufacturing a closed cross-section structure part, comprising: a roll forming machine that forms a three-dimensional object from a welded part as a starting part.