Metal plate material bending method, and bent metal plate product

Abstract

To provide a metal plate bending method that can achieve a prescribed bending angle, and can maintain the bending angle.SOLUTION: A metal plate bending method comprises: a first process in which slits (3) parallel to a bending line (BL) are alternately formed on both sides of the bending line; and a second process in which a metal plate material (P) is bent along the bending line. In the first process, a slit is formed without overlapping a first slit formation range (S1) corresponding to a first slit (31) on a first plate part (1) on one side of the bending line and a second slit formation range (S2) corresponding to a second slit (32) on a second plate part (2) on the other side. In the second process, the metal plate material is bent so that a cut surface on a side opposite to the bending line of the first slit is brought into surface contact with a second inner surface on a bending inner side of the second plate part, and a cut surface on a side opposite to the bending line of the second slit is brought into surface contact with a first inner surface on a bending inner side of the first plate part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for bending a metal plate and a product produced by bending a metal plate. [Background technology]

[0002] The following Patent Document 1 discloses a bending method for metal plates. Patent Document 1 describes the bending method for metal plates described in Patent Document 2 as a conventional technique (see Figs. 2, 2A, and 2B in Patent Document 1). Patent Documents 1 and 2 disclose a processing method in which slits are formed alternately on both sides of a bending line of a metal plate, and then the metal plate is bent along the bending line (see Figs. 6, 7, and 9 in Patent Document 1; see Figs. 8-10 in Patent Document 2). Patent Document 2 explains that "a strong bending joint is formed at any angle, including 90 degrees" (see paragraph

[0068] in Patent Document 2). However, Patent Document 1, which describes Patent Document 2 as a conventional technique, explains that the bending method of Patent Document 2 generates gaps in the bent portion (see paragraphs

[0009] -

[0010] in Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4495592 [Patent Document 2] US Patent Application Publication No. 2002 / 0184936 Summary of the Invention [Problem to be solved by the invention]

[0004] One of the purposes of the invention disclosed in Patent Document 1 is to improve the strength reduction caused by deformation under load due to the above-mentioned gaps (see paragraphs

[0011] and

[0010] of Patent Document 1). However, when the inventors actually checked the bending method of Patent Document 1, they confirmed that gaps were also generated in the bent portion. When these gaps are formed, the bending angle cannot be set accurately. In addition, when gaps are formed, the bending angle may change due to external forces even after bending. It is also possible to obtain an accurate joint angle by laser welding two cut members at a right angle, instead of using a bending method in which slits are alternately formed on both sides of the bending line. However, in this case, it is necessary to accurately align the angle between the two members and fix them in place before laser welding, which is time-consuming.

[0005] A first object of the present invention is to provide a method for bending a metal plate material, which can realize a predetermined bending angle and maintain the bending angle. A second object of the present invention is to provide a bent product of a metal plate material, which can easily realize a predetermined bending angle during bending and maintain the bending angle. [Means for solving the problem]

[0006] The method for bending a metal sheet according to the present invention includes a first step of forming slits parallel to a bending line of the metal sheet alternately on both sides of the bending line, and a second step of bending the metal sheet along the bending line. Here, a portion on one side of the bending line of the metal sheet is a first plate portion, and a portion on the other side is a second plate portion, and a plurality of slits intermittently formed in the first plate portion among the slits are called first slits, and a plurality of slits intermittently formed in the second plate portion among the slits are called second slits. In the first step, the slits are formed on the bending line without overlapping a first slit forming range, which is a range formed by translating the first slit perpendicularly to the bending line and overlapping it with the bending line, and a second slit forming range, which is a range formed on the bending line by translating the second slit perpendicularly to the bending line. In the second step, the metal plate is bent so that the cut surface of the first slit opposite the bending line is in surface contact with a second inner surface on the inside of the bend of the second plate portion, and the cut surface of the second slit opposite the bending line is in surface contact with a first inner surface on the inside of the bend of the first plate portion.

[0007] In the bent metal sheet according to the present invention, slits are formed alternately on both sides of the bending line, parallel to the bending line. The portion on one side of the bending line of the metal sheet is a first plate portion, and the portion on the other side is a second plate portion, and a plurality of slits intermittently formed on the first plate portion among the slits are first slits, and a plurality of slits intermittently formed on the second plate portion among the slits are second slits. A first slit forming range, which is a range formed by translating the first slit perpendicularly to the bending line and overlapping it on the bending line, and a second slit forming range, which is a range formed on the bending line by translating the second slit perpendicularly to the bending line, do not overlap on the bending line. The cut surface of the first slit on the opposite side to the bending line is in surface contact with the second inner surface on the inside of the bend of the second plate portion, and the cut surface of the second slit on the opposite side to the bending line is in surface contact with the first inner surface on the inside of the bend of the first plate portion. The metal sheet does not have an outer edge parallel to the bending line. Effect of the Invention

[0008] According to the method for bending a metal plate material of the present invention, a predetermined bending angle can be realized and the bending angle can be maintained. Also, according to the bent metal plate material of the present invention, a predetermined bending angle can be easily realized during bending and the bending angle can be maintained. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing the upper surface of a bent product of a metal plate according to the embodiment. [Diagram 2] 2 is a perspective view showing the lower surface of the bent product shown in FIG. 1. [Diagram 3] FIG. 3 is a development view of the bent product shown in FIGS. 1 and 2. [Figure 4] 4 is an enlarged plan view of a bent portion in the development shown in FIG. 3. [Diagram 5]FIG. 3 is an enlarged perspective view of a bent portion in the bent product shown in FIGS. 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A bent product of a metal plate material according to an embodiment (hereinafter simply referred to as a bent product) will be described together with a bending method according to an embodiment (hereinafter simply referred to as a bending method) with reference to the drawings.

[0011] 1 and 2 show the processed product Q after processing. The processed product Q has a rectangular first plate portion 1 and a right-angled triangular second plate portion 2 erected from two opposing sides of the first plate portion 1. The angle between the first plate portion 1 and the second plate portion 2 is a right angle. Therefore, the pair of second plate portions 2 are parallel to each other. The boundary between the first plate portion 1 and the second plate portion 2 is bent by bending. Here, as shown in FIG. 2, the inner surface of the bent first plate portion 1 is called the first inner surface 10, and the inner surface of the bent second plate portion 2 is called the second inner surface 20.

[0012] FIG. 3 shows a development of the processed product Q, and shows the metal plate P before bending. In FIG. 3, the dimensional ratio of each part is not shown accurately for ease of viewing. The dimensions of each part will be mentioned in turn in the following description of the embodiment. The metal plate P in this embodiment is a stainless steel plate (SUS304) having a thickness of 1.0 mm. FIG. 4 shows an enlarged plan view of the bent part of the developed metal plate P shown in FIG. 3. As shown in FIG. 4, a bending line BL is set at the boundary between the first plate part 1 and the second plate part 2 to be bent. In other words, one side of the bending line BL of the metal plate P is the first plate part 1, and the other side is the second plate part 2.

[0013] On both sides of the bending line BL, slits 3 parallel to the bending line BL are alternately formed. In this embodiment, the slits 3 are formed by laser processing. Here, among the slits 3, a plurality of slits 3 intermittently formed in the first plate portion 1 are referred to as first slits 31, and among the slits 3, a plurality of slits 3 intermittently formed in the second plate portion 2 are referred to as second slits 32. In addition, the range formed by moving the first slits 31 in parallel to the bending line BL and overlapping it on the bending line BL is referred to as the first slit forming range S1. Similarly, the range formed by moving the second slits 32 in parallel to the bending line BL and overlapping it on the bending line BL is referred to as the second slit forming range S2. These parallel movements are performed perpendicular to the bending line BL.

[0014] When the slits 3 are formed (first step), the slits 3 are formed so that the first slit formation area S1 and the second slit formation area S2 do not overlap on the bending line BL. In this embodiment, the slits 3 (first slits 31 and second slits 32) are formed so that the first slit formation area S1 and the second slit formation area S2 are alternately arranged on the bending line BL without any gap. As described above, in this embodiment, the slits 3 are formed by laser processing, and the laser path LP of the laser light during laser processing is illustrated in FIG.

[0015] When a pinhole is formed in the metal plate P by the laser light, a diameter is generated in the pinhole, and when a slit 3 is formed, a width W is generated in the slit 3. These diameters and widths W are almost the same as the focused diameter of the laser light. Therefore, a gap g is formed on the bending line BL between the laser path LP of the first slit 31 and the laser path LP of the second slit 32, and this gap g is almost equal to the focused diameter. When the slit 3 is formed according to these laser paths LP, no gap is formed on the bending line BL between the first slit 31 and the second slit 32 due to the influence of the focused diameter described above. In laser processing, the width W can be made very small, and for example, the width W can be made 0.2 mm.

[0016] In this embodiment, taking into consideration the thickness (1.0 mm) of the metal plate material P and the width W (0.2 mm) of the slits 3, the distance D between the bending line BL and the laser path LP is set to 0.5 mm, and the length of each slit 3 is set to 10.0 mm. The length of each slit 3 may be any value within the range of 5.0 to 10.0 mm. Each slit 3 is formed perpendicular to the metal plate material P.

[0017] 5 shows an enlarged perspective view of the bent portion of the workpiece Q after bending. As shown in FIG. 4 and FIG. 5, simply by bending along the bending line BL (second step), the cut surface 310 of the first slit 31 on the opposite side of the bending line BL and the second inner surface 20 on the inner side of the bend of the second plate portion 2 come into surface contact. The cut surface 310 can also be said to be the cut surface 310 of the first slit 31 that is farther from the bending line BL. Similarly, simply by bending along the bending line BL, the cut surface 320 of the second slit 32 on the opposite side of the bending line BL and the first inner surface 10 on the inner side of the bend of the first plate portion 1 come into surface contact. The cut surface 320 can also be said to be the cut surface 320 of the second slit 32 that is farther from the bending line BL.

[0018] As shown in Fig. 5, the first slit 31 and the second slit 32 are each widened on the outside of the bend by the bending process, and the connection portion 300 between the end of the first slit 31 and the end of the second slit 32 is slightly twisted. Then, the second plate portion 2 is attracted to the first plate portion 1 by these connection portions 300, and the second inner surface 20 thereof is brought into surface contact with the cut surface 310. Similarly, the first plate portion 1 is attracted to the second plate portion 2 by these connection portions 300, and the first inner surface 10 thereof is brought into surface contact with the cut surface 320. As a result, the first plate portion 1 and the second plate portion 2 are bent forming a right angle with each other, and this right angle is firmly maintained by the surface contact between the cut surface 310 and the second inner surface 20 and the surface contact between the cut surface 320 and the first inner surface 10.

[0019] In this embodiment, since the thickness of the metal plate P is 1.0 mm, bending along the bending line BL was performed by hand. The second plate portion 2 was fixed to a vice, and the first plate portion 1 was bent by hand relative to the second plate portion 2. In this embodiment, a vice was used because the second plate portion 2 has an acute angle as described above, but depending on the shape of the metal plate P (workpiece Q), bending can also be performed by hand without using a vice.

[0020] This is compared with the case where the slit 3 is not formed and the bending process is performed by a press brake. When there is an acute inclined portion close to the bending process line BL, i.e., the most acute angle of the second plate portion 2 of the right triangle, as in the metal plate material P of this embodiment, the area to receive this acute angle portion during bending process by the press brake cannot be sufficiently secured. For this reason, the press brake may not be able to bend this acute angle portion firmly. In this case, the bending angle of the acute angle portion becomes a slightly obtuse angle. However, by forming the slit 3 as in this embodiment, it is possible to bend the bend line BL firmly at a right angle over the entire length.

[0021] Furthermore, in bending by a press brake that does not form slits 3, a bend R (bend curve) is formed in the bent portion, but according to this embodiment, a sharp bend edge can be realized. Also, according to this embodiment, as described above, the right angle is firmly maintained by the surface contact between cut surface 310 and second inner surface 20, and the surface contact between cut surface 320 and first inner surface 10, so there is no need to consider springback, which returns the bend angle after bending.

[0022] In addition, if the metal plate material P before bending does not have an outer edge parallel to the bending line BL as in this embodiment, it is difficult to position it by "butting" with a press brake. Although the apex of the second plate portion 2 of the metal plate material P of this embodiment can be butted against the back gauge of the press brake, it is difficult to match the bending line BL with the bending line of the press brake. Therefore, it is difficult to bend the shape of the metal plate material P of this embodiment with a press brake. However, as described above, according to this embodiment, it is possible to accurately bend the metal plate material P without using a machine.

[0023] As described above, the metal plate P of this embodiment is difficult to bend with a press brake due to its shape. However, this does not mean that bending along the bending line BL cannot be performed with a press brake in the present invention. For example, by forming a slit in a thick metal plate and bending it, the bending load can be reduced. In other words, by forming a slit, it is possible to reduce the processing load and bend a metal plate of a thickness that cannot be bent with a press brake. If the metal plate P has an outer edge parallel to the bending line BL, it is easy to make the bending line BL coincide with the bending line of the press brake by abutting the outer edge against the back gauge of the press brake.

[0024] The bending method is compared with the bending methods disclosed in Patent Documents 1 and 2. In the bending methods disclosed in Patent Documents 1 and 2, slits are formed so that the first slit forming range S1 and the second slit forming range S2 overlap on the bending line BL. Therefore, the portion corresponding to the above-mentioned connection portion 300 of this embodiment extends along the bending line BL after bending. In contrast, the above-mentioned connection portion 300 of this embodiment in which the first slit forming range S1 and the second slit forming range S2 do not overlap on the bending line BL extends so as to intersect with the bending line BL. Therefore, the first plate portion 1 and the second plate portion 2 are attracted to each other by the connection portion 300 in the method of this embodiment compared to the methods disclosed in Patent Documents 1 and 2. As a result, the surface contact between the cutting surface 310 and the second inner surface 20 and the surface contact between the cutting surface 320 and the first inner surface 10 can be more reliably realized.

[0025] Furthermore, since the portion corresponding to the connection portion 300 in Patent Documents 1 and 2 is longer than the connection portion 300 in this embodiment, this corresponding portion itself comes into contact with the first inner surface 10 and the second inner surface 20 and the surfaces corresponding to the cut surfaces 310, 320 of the slit 3. For this reason, the surface contact between the surfaces corresponding to the cut surfaces 310, 320 and the surfaces corresponding to the first inner surface 10 and the second inner surface 20 is hindered. Due to these factors, it is thought that the above-mentioned gap occurs in the bending portion in the methods disclosed in Patent Documents 1 and 2. According to this embodiment, the first plate portion 1 and the second plate portion 2 are attracted to each other more, and the connection portion 300 does not hinder the surface contact between the cut surfaces 310, 320 of the slit 3 and the first inner surface 10 or the second inner surface 20, so that such a gap does not occur.

[0026] According to this embodiment, after bending, the inner corner 4 (see FIG. 2) where the first inner surface 10 and the second inner surface 20 intersect can be laser welded intermittently or continuously parallel to the bending line BL (third step) to further improve the rigidity and strength. As described above, in the bending methods disclosed in Patent Documents 1 and 2, a gap is formed in the bent portion corresponding to the inner corner 4, so that when laser welding is performed, the molten metal blows through the gap and cannot be welded normally. In addition, the blow-through of the molten metal reduces the appearance quality of the bent outside of the workpiece. However, according to this embodiment, a gap is not formed in the inner corner 4, so that it can be firmly laser welded, and the rigidity and strength of the workpiece Q (particularly the bent portion) can be further improved.

[0027] The bending method according to the above embodiment includes a first step of forming slits 3 (31, 32) parallel to the bending line BL alternately on both sides of the bending line BL of the metal plate P, and a second step of bending the metal plate P along the bending line BL. In the first step, the slits 3 (31, 32) are formed without overlapping the first slit forming range S1 and the second slit forming range S2 on the bending line BL. In the second step, the metal plate P is bent so that the cut surface 310 of the first slit 31 on the opposite side of the bending line BL is brought into surface contact with the second inner surface 20, and the cut surface 320 of the second slit 32 on the opposite side of the bending line BL is brought into surface contact with the first inner surface 10. Therefore, according to the bending method according to the above embodiment, a predetermined bending angle can be realized and the bending angle can be maintained without forming a gap in the bent portion after bending.

[0028] Furthermore, after the second step, a third step may be further provided in which the inner corner 4 where the first inner surface 10 and the second inner surface 20 intersect is laser-welded intermittently or continuously parallel to the bending line BL. In this case, the rigidity and strength of the workpiece Q (particularly the bent portion) can be further improved. In particular, since no gap is formed during welding, welding can be performed reliably.

[0029] Furthermore, in the second step, the metal plate P may be bent along the bending line BL using a press brake. Even if the metal plate P is thick, a predetermined bending angle can be achieved and a sharp bent edge (without raised radius) can be achieved. Furthermore, since the bending load can be reduced by forming the slits 3, it is possible to bend metal plates of a thickness that cannot be bent by a press brake.

[0030] In the bent product Q according to the above embodiment, slits 3 (31, 32) parallel to the bending line BL are formed alternately on both sides of the bending line BL. The first slit forming range S1 and the second slit forming range S2 do not overlap on the bending line BL. The cut surface 310 of the first slit 31 on the opposite side of the bending line BL is in surface contact with the second inner surface 20, and the cut surface 320 of the second slit 32 on the opposite side of the bending line BL is in surface contact with the first inner surface 10. The metal plate material P does not have an outer edge parallel to the bending line BL. Since the metal plate material P does not have an outer edge parallel to the bending line BL, it is difficult to position the metal plate material P by "butting" with a press brake, but it is possible to accurately bend the metal plate material P without using a machine. It is easy to achieve a predetermined bending angle during bending, and the bending angle can be maintained.

[0031] Although the above-mentioned embodiment has been described, the present invention is not limited to these, and various modifications are possible within the scope of the gist of the present embodiment. For example, the slit 3 is preferably laser processed because the width W can be made small, but it may be formed by other processing methods. For example, the slit 3 may be formed by water jet processing. However, in order to water jet process a metal plate material, it is necessary to mix an abrasive (abrasive) with the water to be sprayed. For this reason, the width W of the slit 3 can be made smaller by laser processing. The slit 3 may also be formed by press processing. If the slit 3 is formed in the metal plate material by press processing, the periphery of the slit 3 is plastically deformed as if it were crushed, making it difficult to achieve precision.

[0032] In the above embodiment, no gap was formed between the first slit 31 and the second slit 32 on the bending line BL. However, when the thickness of the metal plate material P is large, a gap G may be formed between the first slit forming area S1 and the second slit forming area S2 depending on the thickness, as shown in the lower part of Fig. 4. In the present invention, it is sufficient that the first slit forming area S1 and the second slit forming area S2 do not overlap on the bending line BL. [Explanation of symbols]

[0033] P Metal plate material BL bending wire Q Bending products 1 First plate part 10 (first plate portion 1) first inner surface 2 Second plate part 20 (of second plate portion 2) second inner surface 3 Slit 31 First Slit 32 Second slit 310 (the side opposite to the bending line BL of the first slit 31) cut surface 320 (the opposite side of the bending line BL of the second slit 32) cut surface S1 First slit forming range S2 Second slit forming range 4 Inner corner

Claims

1. A first step of forming slits alternately on both sides of a bending line of a metal plate material, the slits being parallel to the bending line; A second step of bending the metal plate material along the bending line, When a portion on one side of the bending process line of the metal plate is defined as a first plate portion and a portion on the other side is defined as a second plate portion, and when a plurality of slits intermittently formed in the first plate portion among the slits are defined as first slits and a plurality of slits intermittently formed in the second plate portion among the slits are defined as second slits, In the first step, a first slit forming range, which is a range formed by translating the first slit perpendicularly to the bending line and overlapping it on the bending line, and a second slit forming range, which is a range formed by translating the second slit perpendicularly to the bending line and overlapping it on the bending line, are formed on the bending line without overlapping each other, In the second step, the metal plate is bent so that a cut surface of the first slit opposite the bending line is brought into surface contact with a second inner surface on the inside of the bend of the second plate portion, and a cut surface of the second slit opposite the bending line is brought into surface contact with a first inner surface on the inside of the bend of the first plate portion.

2. 2. The method for bending a metal plate according to claim 1, further comprising a third step of intermittently or continuously laser welding an inner corner where the first inner surface and the second inner surface intersect, parallel to the bending line, after the second step.

3. 3. The method for bending a metal plate according to claim 1, wherein in the second step, the metal plate is bent along the bending line using a press brake.

4. A bent product of a metal plate material, Slits are formed alternately on both sides of the bending line parallel to the bending line, When a portion on one side of the bending process line of the metal plate is defined as a first plate portion and a portion on the other side is defined as a second plate portion, and when a plurality of slits intermittently formed in the first plate portion among the slits are defined as first slits and a plurality of slits intermittently formed in the second plate portion among the slits are defined as second slits, A first slit forming range, which is a range formed by translating the first slit perpendicularly to the bending line and overlapping it on the bending line, and a second slit forming range, which is a range formed by translating the second slit perpendicularly to the bending line and overlapping it on the bending line, do not overlap on the bending line, The cut surface of the first slit opposite the bending line is in surface contact with a second inner surface on the inside of the bend of the second plate portion, and the cut surface of the second slit opposite the bending line is in surface contact with a first inner surface on the inside of the bend of the first plate portion, A bent metal sheet, wherein the metal sheet does not have an outer edge parallel to the bending line.

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