TWI477329B - Method for manufacturing curvilineal closed structure parts and apparatus for the same - Google Patents

Description

Method and device for manufacturing closed-section structural part having curved shape

The present invention relates to a method and an apparatus for manufacturing a closed-section structural member having a curved shape. In particular, there is a method and an apparatus for manufacturing a closed-section structural member having a curved shape, which is conventionally closed in the automotive, home appliance, and other fields by joining two individually formed individual members. The parts manufactured by the cross-section can be advantageously provided with a curved shape for the purpose of light weight, collision characteristics, and rigidity improvement, and a cross-sectional shape that spans the entire length of the part.

Patent Document 1 describes a technique in which a high-tensile steel sheet is roll-formed to produce a molded body having a fixed cross-sectional shape, and then the molded body is subjected to induction hardening and further in the longitudinal direction of the molded body (and In the direction orthogonal to the cross section, the bending process (sweep molding) is performed in a circular arc shape with a fixed curvature, thereby manufacturing bumper reinforcements as shock absorbers for vehicles.

Patent Document 2 discloses a technique in which a pair of rotating rolls disposed so as to sandwich a conveying path of a thin metal plate and a rotating roll disposed below the pair of rotating rolls are provided in the roll forming apparatus. Further, the interval between the rolls of the pair of rotating rolls can be changed, and the rotating rolls disposed under the pair of rotating rolls can be moved up and down; and as the roll forming apparatus and the part manufacturing method using the apparatus, the strips are made long When a part of the thin metal plate is transported between the pair of rotating rolls, the interval between the rolls of the pair of rotating rolls is changed, and the metal thin plate to be conveyed is partially deformed so as to be placed under the surface. The side rotating rolls are raised and lowered to thereby manufacture roll-formed parts having the same cross section in the longitudinal direction.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-120227

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-30023

In the technique of Patent Document 1, after a closed-section part having a fixed cross-sectional shape is formed by ordinary roll forming, induction hardening is performed, and curvature is imparted to three bending pieces. To manufacture curved closed section parts. However, it is not possible to form a part in which the cross-sectional shape in the longitudinal direction of the part is not fixed. Moreover, the direction of curvature imparting is limited to the two-dimensional direction.

The technique of Patent Document 2 is a forming technique in which the cross-sectional shape can be changed in the longitudinal direction of the component by the molding device, but at the same time, the curved shape in the longitudinal direction cannot be imparted, and the forming device has In addition to the ordinary roll forming of a pair of rotating rolls, a rotating roll for changing the sectional shape in the longitudinal direction of the part is attached below the pair of rotating rolls.

As described above, in the prior art, the cross-sectional shape (in detail, the direction orthogonal to the longitudinal direction of the component, that is, the cross-sectional shape in the component width direction) cannot be deformed in the longitudinal direction of the component. In addition, the three-dimensional shape of the bending (or the twisting) in the longitudinal direction of the component is applied simultaneously. Therefore, it is necessary to set the profiled and three-dimensional shape of each section to a separate molding step, which requires a corresponding cost. And, in order to When a high-strength steel sheet is used as a material for weight reduction, molding defects are likely to occur in the bending process after the irregularities of the respective sections of the parts.

In order to solve the above problems, the inventors of the present invention have conducted active research, and as a result, it has been found that two sections of metal sheets can be bent in the longitudinal direction of the part by simultaneously forming the sections of the parts and forming the three-dimensional shape. The closed-section structural part of the profiled cross-sectional shape has completed the present invention.

That is, the present invention is as follows.

(1) A method of manufacturing a closed-section structural member, wherein a closed section having a deformed cross-sectional shape in which a flange portion is connected to a flange portion in a longitudinal direction of a part is produced from two metal plates In the structural part, the method of manufacturing the closed-section structural part includes a first step of bending a longitudinal direction of the sheet corresponding to the longitudinal direction of the part, and two metal plates corresponding to the flange portion at both ends of the plate width. The press forming is performed to impart a crease to the plate portion corresponding to the non-welded bent portion and the welded portion in the section of the part, and in the second step, the two metal sheets after the press forming are as described above. The convex side of the two metal plates is vertically overlapped, and the creases corresponding to the flange portions corresponding to the upper and lower sides of the width are welded to each other in the longitudinal direction to form a welded portion. Forming a closed-section structure; and a third step of guiding and transporting the obtained closed-section structure by a pair of left and right rotating rolls or a rotating roll below, and by the above The change in the interval of the rolls of the rotating rolls or the raising and lowering of the rotating rolls causes the closed-sectional structure to be three-dimensionally formed from the creases and the welded portion as a starting point to form a desired shape.

(2) A manufacturing apparatus for a closed-section structural component, wherein a closed section having a curved cross section and a welded portion in the longitudinal direction of the component and having a deformed cross-sectional shape in which the flange portion is connected to the welded portion is produced from two metal plates In the structural component, the manufacturing apparatus of the closed-section structural component includes a press molding machine, and is provided with two metal plates that are bent in the longitudinal direction of the plate corresponding to the longitudinal direction of the component, and that have two end portions of the plate width corresponding to the flange portion. Press forming is performed to impart a crease to each of the plate portions corresponding to the non-welded bent portion and the welded portion in the section of the part; and the welding machine has two pieces of the above-mentioned press-formed two metal plates. The convex surface side of the metal plate is vertically overlapped, and the creases corresponding to the flange portion corresponding to the upper and lower sides of the width are welded to each other in the longitudinal direction to form a welded portion to form a closed portion. a cross-sectional structure; and a roll forming machine that guides and conveys the obtained closed-section structure by a pair of left and right rotating rolls or a rotating roll below, and by the above-described rotation The change of the roll interval of the roll or the raising and lowering of the rotating roll causes the closed-sectional structure to be three-dimensionally formed from the crease and the welded portion as a starting point to form a component having a target shape.

According to the present invention, the cross-sectional shape can be changed, and the longitudinal direction of the component and the vertical direction thereof can be imparted by one-time molding, that is, the three-dimensional shape. In the shape, the number of molds is reduced and the assembly step is reduced, and the manufacturing step is simplified, so that the cost can be greatly reduced.

Further, since a predetermined shape can be obtained mainly by bending, it is easy to manufacture a part made of an ultrahigh-tensile steel sheet.

FIG. 2 is a schematic perspective view showing an example of a part (a closed-sectional structure part having a curved shape) 10 to be manufactured in the present invention.

In the example of FIG. 2, the cross-sectional shape (the meaning of the cross-sectional shape in the width direction, the same applies hereinafter) is a quadrangular shape, and has a curvature in the longitudinal direction, and the initial end portion in the longitudinal direction and the end portion have different cross-sectional shapes (that is, Alien). In other words, the shape is such that the one end of the quadrangular cross section has a length of 30 mm, the length of one end of the end portion is 20 mm, and the total length in the longitudinal direction (the shortest distance between both ends in the longitudinal direction) is 300 mm, and the radius of curvature of the curved portion is on the starting end side. It is 400 mm, and is 400 mm on the terminal side, and the direction in which the center portion in the longitudinal direction of the component (the position from the both ends in the longitudinal direction is 150 mm) is reversed left and right. Further, of the two pairs of vertices located at the diagonal positions of the quadrilateral, one pair is the welded portion 11, and the other pair is the non-welded bent portion 12. The 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 step of the present invention. Here, the case where the components of FIG. 2 are manufactured will be described as an example. The parts of the example of Fig. 2 are the parts of the example 1 shown in Fig. 3 (a).

3(a) to 3(c), in order to bend the two metal plates 1a and 1b in the longitudinal direction of the plate corresponding to the longitudinal direction of the part, a bending line (B) is respectively provided in the metal plate 1a. (B), in the metal plate 1b The bending line (B') (B') is provided as two bending lines on the width end side corresponding to the welded portion 11 of the member 10 connected to the flange portion 13, and bending is provided in the metal plate 1a, respectively. In the line (A), a bending line (A') is provided in the metal plate 1b as one bending line inside the width corresponding to the non-welded bending portion 12.

(Step 1)

The first step is a preforming step. Using the press molding machine 20 having a punch 3 and a die 4, the metal plate 1 has a curved line inside the width corresponding to the non-welded bent portion 12 among the four vertices of the four-sided cross section of the part. The portion of (A) (A') and the portion of the bending line (B) (B') on the width end side corresponding to the welded portion 11 are press-formed so as to impart the fold 2 . The shape of the punch 3 and the mold 4 is designed in such a manner as to impart the crease 2. Further, the radius of curvature in the plate width direction of the portion of the crease 2 is a fixed value across each of the creases 2 across the entire length of the plate.

(Step 2)

The second step is a flange portion welding step. The pre-formed metal plates 1a and 1b are formed on the convex side of the metal plates 1a and 1b (in the first step, the crease 2 is formed by bending and the convex surface is formed). In the welding machine 30, the corresponding portions of the flange portions 13 that face each other on the left and right sides of the width are pressed by the upper and lower pressing jigs 6a and 6b, so that the left end of the width overlapping the upper and lower sides is The creases 2 at the bending line (B) (B') portion and the creases 2 at the bending line (B) (B') portion at the right end are welded to each other in the longitudinal direction to form the welded portion 11, Thereby, the closed-section structure 5 is formed. The welding is preferred It is carried out by spot welding, laser welding, and the like. A known spot welding device, a laser welding device, or the like can be used for the welding device (not shown).

(Step 3)

The third step is a roll forming step. That is, the closed-section structure 5 obtained in the previous step is passed through the roll forming machine 40. The roll forming machine 40 guides and conveys the closed cross-sectional structure 5 by the pair of left and right rotating rolls 40a and 40b or the lower rotating roll 40c, and changes the roll interval of the rotating rolls 40a and 40b. Further, by the raising and lowering of the rotating roller 40c, the closed-end structure 5 is three-dimensionally formed by the crease 2 and the welded portion 11 as a starting point to form a component 10 having a target shape.

The shape of the rotating roller is set to a shape in which the roller abutting portion of the closed-sectional structure as the workpiece is not displaced or the like, and can be stably guided. The rotating rolls of 40a, 40b, and 40c of Fig. 1 exhibit a V shape as one example, but are not limited thereto. In particular, in the rotating rolls 40a and 40b that guide the flange portion 13, a slit 14 for guiding the flange is provided at the bottom. The roller interval of the rotating roller (corresponding to the pressing force from the left and right sides of the roller to the closed-section structure) and the lifting position of the rotating roller (corresponding to the upper thrust from the lower side of the roller for the closed-section structure) are obtained. The way the part target shape changes. The method of changing the roller interval of the rotating roller and the lifting position of the rotating roller can be determined in advance based on theoretical analysis or experiment. Further, a rotating roller corresponding to the lower rotating roller may be provided above to form a target shape of the component.

Further, in this example, since the target shape of the part is a shape without distortion, in order to achieve the shape, in FIG. 3(a), two pieces are used. Each of the metal plates 1 can achieve a twisted target shape by one or both of the following methods: a total of three bending lines for two bending lines on the width end side and one bending line on the inner side of the width. The curvature radii are the same and the center points of curvature are on the same straight line; and when the target shape of the parts is a twisted shape, the curvature radii are different or the center points of curvature are not in the same straight line with respect to the total of three bending lines. on-line. In the first step to the third step, in the same manner as in the case of the quadrangular shape, a mold having a shape corresponding to the shape of the part, a rotating roll, or the like can be used to manufacture the closed-section structure part.

For example, when the hexagonal cross-section member shown in FIG. 5 is to be manufactured, the non-welded curved portion 12 is increased by two more than the rectangular cross-section of FIG. 2 . Here, in response to this, as shown in FIG. 6, the bending line (A) (B) (A') (B') on the inner side of the width is opposed to the upper side and the lower side (blank), respectively. Set 4 roots.

Further, as a manufacturing step, a step shown in FIG. 4 is applied to the device member used in FIG. 1 in accordance with the change of the quadrangular cross section to the hexagonal cross section. That is, the shape of the mold used in the first step (preform step) is a mold shape in which the fold 2 is given to the portion of the bending line (A) (B) (A') (B') of FIG. 6 . In the second step (the flange portion welding step), the pressing jig 6 is formed into a cross-sectional shape conforming to the shape of the base after the preforming. In the third step (roll forming step), the roll profile of the lower rotating roll 40c is, for example, a flat bottom shape in which a hexagonal one side portion can be stably guided. Except for these changes, it is the same as Fig. 1. Thereby, the shape after forming shown on the lower side of FIG. 6, It can be achieved with high precision and easily.

[Example]

In the example, the following items are common matters.

[Particle target shape] The cross section has a shape in which four sides (each corner is a right angle) having a different shape in the longitudinal direction of the component, and has a flange portion connected to the welded portion and has an S-shape in the longitudinal direction of the component. bending.

[Material Metal Plate] A cold-rolled steel sheet (thickness: 1.4 mm) having a tensile strength of 1,180 MPa was cut out, and two curved bases A and B having an S-shape corresponding to the target shape of the part were cut out as materials.

[Welding conditions] Laser welding, laser output 3.8kW, welding speed 2.5m/min, laser focusing diameter 2mm

(Example 1)

As shown in Fig. 3 (a), the position of the center of the one base 1a (base A) between the two bending lines (B) and (B) on the width end side is set as the bending line which should be the fold 2 (A); the position of the center of the other base 1b (base B) between the two bending lines (B') (B') on the width end side is set to be a bending line which should be the crease 2 (A) '). In the first step, the two substrates A and B are pre-formed as described above, and are provided with creases 2 along the bending line (A) (A') (B) (B'), respectively; In the step, when superimposing as described above, the base A is used as the upper side, and the base B is used as the lower side, and the bending line (B) (B') portion on the width end side of the upper and lower sides is subjected to laser welding; In the third step, the closed-section structure 5 is subjected to roll forming as described above to obtain the part 10 .

(Example 2)

As shown in Fig. 3(b), one base 1a (base A) is placed on the left side of the two bending lines (B) and (B) on the width end side, and is set to be crease 2 The bending line (A); the other base 1b (substrate B) is located between the two bending lines (B') (B') on the width end side than the center (on the center position) The position on the left side is a symmetrical position), and the bending line (A') which should be the crease 2 is set. In the first step, the two substrates A and B are pre-formed as described above, and are provided with creases 2 along the bending line (A) (A') (B) (B'), respectively; In the step of superimposing as described above, the base A is used as the upper side, and the base B is used as the lower side, and the bending lines (B) and (B') on the width end sides of the upper and lower sides are subjected to laser welding; In the third step, the obtained closed-section structure 5 is subjected to roll forming as described above to obtain a part 10 .

(Comparative example)

A single base material having a shape different from that of the example is cut out from the same steel sheet as the example, and the forming start portion and the forming end portion are formed into a cross-sectional shape having a different shape by roll forming as in the prior art. The forming process (shaped cross-section) is performed to form the intermediate-shaped component 15 as shown in Fig. 3 (c), and the intermediate-shaped component 15 is bent by a three-point bending method by roll forming. Thereby, the final shape part 16 is obtained.

For the examples and comparative examples, an evaluation of whether or not formable is made. As a result, in any of the examples, the first step to the third step can be formed, and the component 10 after the third step has a target shape, and there are no formation defects such as fracture, buckling, and wrinkles. On the other hand, in the comparative example, the profile is broken. In the intermediate shape part 15 after the surface, there is no formation defect occurrence portion, but in the final shape part 16 after the bending process, buckling occurs in the illustrated portion.

1‧‧‧Metal plates (a, b are one of the two and the other, also known as the base)

2‧‧‧creases (corresponding to bending lines (A) (A'), (B) (B'))

3‧‧‧ Punch

4‧‧‧

5‧‧‧Closed-section structures

6‧‧‧Squeeze fixtures (a, b are upper and lower extrusion clamps)

10‧‧‧ Parts (closed-section structural parts having a curved shape as a manufacturing target in the present invention)

11‧‧‧Weld Department

12‧‧‧ Non-welded bends

13‧‧‧Flange

14‧‧‧Incision

15‧‧‧ intermediate shape parts of the comparative example

16‧‧‧The final shape part of the comparative example

20‧‧‧Compression molding machine

30‧‧‧ welding machine

40‧‧‧ Roll Forming Machine

40a, 40b‧‧‧Rotating roller

40c‧‧‧Rotating roller

(A)(A')(B)(B')‧‧‧Bending line

Fig. 1 is an explanatory view of a manufacturing step of the present invention.

Fig. 2 is a schematic perspective view showing an example of a target shape of a part.

3(a) to 3(c) are schematic diagrams showing the manufacturing steps of the parts of the examples and the comparative examples.

Fig. 4 is an explanatory view showing a manufacturing procedure of a hexagonal cross-section member.

FIG. 5 is a schematic perspective view showing an example of a target shape of a hexagonal cross-section member.

Fig. 6 is a schematic view showing a manufacturing method of a hexagonal cross-section member.

1‧‧‧Metal plates (a, b are one of the two and the other, also known as the base)

2‧‧‧creases (corresponding to bending lines (A) (A'), (B) (B'))

3‧‧‧ Punch

4‧‧‧

5‧‧‧Closed-section structures

6‧‧‧Squeeze fixtures (a, b are upper and lower extrusion clamps)

11‧‧‧Weld Department

13‧‧‧Flange

14‧‧‧Incision

20‧‧‧Compression molding machine

40‧‧‧ Roll Forming Machine

40a, 40b‧‧‧Rotating roller

40c‧‧‧Rotating roller

Claims (2)

A method for producing a closed-section structural member, wherein a closed-section structural member having a curved cross-section and a welded portion in a longitudinal direction of the component and having a different-shaped cross-sectional shape in which the flange portion is connected to the welded portion is produced from two metal plates. The method for manufacturing the closed-section structural member includes a first step of providing a bending in a longitudinal direction of the sheet corresponding to the longitudinal bending of the component, and two metal plates corresponding to the flange portion at both ends of the plate width. Press forming is performed by providing a crease in a portion corresponding to the non-welded bent portion and the welded portion in the section of the part, and in the second step, the two metal sheets after the press forming are made of the above two metals The convex side of the plate is vertically overlapped, and the creases corresponding to the flange portion corresponding to the upper and lower sides of the width are welded to each other in the longitudinal direction to form a welded portion to form a closed portion. In the third step, the obtained closed-section structure is guided and conveyed by a pair of left and right rotating rolls or a rotating roll below, and the roll by the rotating roll In the change of the interval, or by the raising and lowering of the rotating roller, the closed-sectional structure is three-dimensionally formed from the crease and the welded portion as a starting point to form a component having a target shape. A manufacturing apparatus for a closed-section structural component, which is a closed-section structural part having a deformed cross-sectional shape in which a bent portion and a welded portion are formed in a longitudinal direction of a component, and a flange portion is connected to the welded portion by two metal plates. The manufacturing apparatus of the closed-section structure part includes a press molding machine, and a plate length corresponding to the bending of the length direction of the part is provided The two metal plates corresponding to the flange portions at both ends of the plate width are creased in a direction in which the plate portions corresponding to the non-welded bent portions and the welded portions in the section of the part are respectively provided with a crease. In the welding machine, the two metal plates after the press forming are vertically overlapped so that the convex sides of the two metal plates are outward, and the flanges are vertically opposed to each other on the left and right sides of the width. The creases of the corresponding portions are welded to each other in the longitudinal direction to form a welded portion to form a closed-sectional structure, and a roll forming machine is used to form a closed-end structure obtained by using a pair of left and right rotating rolls Or the lower rotating roller guides and conveys, and the above-mentioned crease and the welded portion are used as a starting point to be closed by the change of the roll interval of the rotating roll or by the raising and lowering of the rotating roll The surface structure is three-dimensionally formed to form a part of the target shape.