Edgewise bending method and edgewise bending device

Abstract

To achieve edgewise bending close to 90° for band plates such as busbars while suppressing deformation.SOLUTION: Starting from a straight state of a band plate X, when a pressing piece 23 is pressed down, a pair of clamp parts 7, 7 rotates in opposite directions at the same peripheral speed around a common fulcrum "C". A side edge 9b of the clamp part 7 on the left side and a side edge 9b of the clamp part 7 on the right side gradually move apart from the joined state in which plate surfaces face in the left-right direction. Namely, a space between concave grooves 13, 13 of the clamp parts expands in a fan shape to form a gap. During this process, an inner surface 13b and an inner surface 13b rise into a mountain-like shape from a state of being linearly continuous. The gradually rising surface is an "angled surface", a plate thickness surface Xb on one side in the edgewise direction of the band plate X is pressed against the "angled surface" and bent, and the contacting side becomes the bent inner surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an edgewise bending method for a plastically workable strip plate and an edgewise bending apparatus used for carrying out the edgewise bending method. [Background technology]

[0002] Busbars (copper sheets), a typical example of strips that can be plastically processed, are conductors used in areas where large amounts of current flow, and have traditionally been widely used in control panels, switchboards, batteries, etc. Recently, with the spread of electric vehicles, bus bars have been attracting attention as a replacement for high-voltage harnesses, which are the mainstream for electrical wiring. Unlike high-voltage harnesses, bus bars have a fixed shape and must be preformed into a specified shape. However, with vehicle space being limited due to the installation of large-capacity batteries and the like, the requirements for three-dimensional molding are becoming increasingly stringent in order to create space for the placement of other electrical components and to enable the bus bars to pass through narrow gaps. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-75310 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the width change portion is created during the blanking stage, the blank yield will be low, and the manufacturing cost will increase significantly. On the other hand, even if an attempt is made to perform edgewise bending by forming processing as described in Patent Document 1 after blanking, if a conventional punch and die for V-bending are used, the pointed tip of the punch will bite into the soft copper material, causing it to crack and the surrounding area to bulge and deform, resulting in insufficient bending workability, particularly for thick bus bars.

[0005] The present invention has been made in consideration of the above-mentioned problems in the conventional art, and has an object to provide a new and useful edgewise bending method that can achieve edgewise bending of close to 90° on plastically processable strip plate such as a bus bar while minimizing deformation, and an edgewise bending apparatus for use in carrying out the edgewise bending method. [Means for solving the problem]

[0006] The present invention has been made to solve the above-mentioned problems, and is an edgewise bending method characterized by clamping a plastically processable strip on both sides and gradually changing the clamp angle in the folding direction of the strip, thereby gradually increasing the surface pressure of the middle portion, which will become the bent portion, while bending the middle portion in the edgewise direction. Preferably, the inner bend surface of the bend is created using a varying clamp angle as the pressing surface.

[0007] The present invention is an edgewise bending device comprising a pair of symmetrical clamping sections which clamp a plastically processable strip by fitting it into groove sections which are arranged in series with the middle section in between, and a rotation means for rotating the pair of clamping sections in opposite directions about a common fulcrum, wherein one side of the middle section of the strip is pressed against the corner surface of the groove section which rises into a mountain shape as the groove section of the pair of clamping sections spreads out like a fan as a gap is formed, thereby forming an inner bent surface and the other side of the middle section of the strip in the edgewise direction.

[0008] Preferably, the clamp portion has opposing surfaces on both sides of the fulcrum, with the opposing surface on one side forming a corner surface of the groove portion, and when the respective groove portions of the pair of clamp portions extend straight and are connected, the opposing surfaces on the other side are brought together, and when the corner surfaces form the most acute angle, the opposing surfaces on the other side are opened. Preferably, a symmetrical triangular gap is formed at the end where the opposing surfaces of one of the clamping parts are joined together, and when a pressing piece having a triangular tip enters the gap, a force is applied in a direction extending from the apex of the triangle to the boundary between the joined opposing surfaces, causing the pair of clamping parts to rotate. Preferably, the tip of the pressing piece has a recessed corner portion consisting of a corner surface and an inner bottom surface, and ultimately, upon rotation, the space between the respective recessed groove portions of the pair of clamping portions expands in a fan shape, the inner bottom surface enters into the gap, and a continuous L-shaped recessed groove is formed by the recessed corner portion and the pair of groove portions, and the corner surface presses against the bent outer surface. Preferably, a support portion having an arcuate peripheral surface provided on the clamp portion side is rotatably fitted into a circular through hole provided in the base table and penetrating in the vertical direction, thereby realizing rotation of the clamp portion. Effect of the Invention

[0009] According to the edgewise bending method of the present invention, it is possible to realize edgewise bending of a plastically workable strip such as a bus bar at an angle close to 90° while suppressing deformation. In addition, a device with a simple structure and good durability has been proposed as an apparatus for performing this edgewise bending method. Assuming its use, the blank yield can be significantly improved, making the bending method fully cost-effective. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of an edgewise bending device according to an embodiment of the present invention; [Diagram 2] 2A and 2B are a top view and two side views of the edgewise bending device of FIG. 1. [Diagram 3] 2 is a top view of the edgewise bending device of FIG. 1, and a cross-sectional view taken along the lines AA and BB. [Figure 4] 2 is an image diagram of a method for edgewise bending a strip plate using the edgewise bending device of FIG. 1. FIG. [Diagram 5] 2 is an explanatory diagram of the operation of the edgewise bending device of FIG. 1. [Figure 6] FIG. 6 is a top view of the edgewise bending apparatus of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An edgewise bending apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings. The edgewise bending device 1 processes a copper plate intended for use as a bus bar as a strip X that can be plastically worked, and has a structure shown in Figs. 1 to 6. For ease of explanation, the directions indicated by the arrows in FIG. 1 are defined as front-rear, left-right, up-down and up-down directions. As shown in FIGS. 1 to 3, a strip X is placed and set on a flat rectangular base stand 3 having a flat upper surface 3a of the edgewise bending device 1.

[0012] A through hole 5 with a circular cross section penetrates straight through the base table 3 in the vertical direction, and the edge of the through hole 5 is visible on the top surface 3a. This through hole 5 has a circular step surface 5a halfway up and down, and the step surface 5a forms a small diameter hole 5b on the upper side and a large diameter hole 5c on the lower side, which are lined up coaxially up and down. The edgewise bending device 1 is configured symmetrically, and the through hole 5 is located in the center of the front half of the base table 3. A pair of clamp parts 7, 7 are disposed so as to cover this through hole 5 from above. The main part of the clamp part 7 is formed from a single flat plate body, and has an outline resembling two rectangular pieces meeting at an obtuse angle.

[0013] Focusing on the right clamp part 7, the rectangular piece 9 located on the rear side is almost square, and the rear edge 9a and the left and right side edges 9b, 9c form part of the outline of the clamp 7. In addition, the corner between the rear edge 9a and the left side edge 9b is slightly cut at an angle of 45° to form a short oblique edge 9d. In front of the square piece 9, the rectangle has a long side that runs diagonally from the front right to the rear left, with the rear right corner overlapping the front part of the square piece 9. The short side of the rectangle is shorter than the edge of the square piece 9, but the rectangle intersects with the front edge of the square piece 9 at an angle, and the front edge 11a and the left and right side edges 11b, 11c appear as part of the outline of the clamp 7, and the left and right side edges 11b, 11c are continuous with the left and right side edges 9b, 9c, respectively. The left side edges 9b and 11b, and the right side edges 9c and 11c intersect at the same vertical position at the same obtuse angle of 135°.

[0014] The area excluding the square piece 9 from the whole, that is, the area surrounded by the front edge 11a, the left and right side edges 11b, 11c, and the area corresponding to the front edge of the square piece 9, constitutes the square piece 11. The square pieces 9 and 11 are physically separate bodies, but are integrated by being connected via a support portion 15, which will be described later. The upper surface 7a of the clamp portion 7 is recessed to provide a groove portion 13. The groove portion 13 has a horizontally long rectangular concave cross section that is open upward. The groove portion 13 extends straight, and the concave surface is composed of a pair of inner side surfaces 13a, 13b and an inner bottom surface 13c that face each other in parallel.

[0015] The groove 13 is formed by recessing the side of the square piece 9, and of the inner surfaces 13a and 13b, the inner surface 13b located at the front is formed by the rear edge of the square piece 11 and extends in the left-right direction. The concave surface is open at both ends in the left-right direction. The square piece 11 has a two-layer structure to ensure strength, with the upper layer, which has greater strength, forming the inner surface 13b. The strip X is fitted into the groove 13 with one plate surface Xa overlapping the inner bottom surface 13c with a small clearance. At that time, the other plate surface Xa becomes substantially flush with the upper surface 7a of the clamp portion 7.

[0016] A support portion 15 is attached to the underside of the clamp portion 7. This support portion 15 is in the shape of an arc column, and the angle of the arc is 135°, which is the obtuse angle of the clamp 7 described above. In addition, an annular stepped surface 15a is provided midway on the circumferential surface, and through this stepped surface 15a, a small diameter surface 15b is formed on the upper side and a large diameter surface 15c is formed on the lower side, and are arranged coaxially in the vertical direction. When viewed from above, the support portion 15 is entirely hidden by the clamp portion 7. The support portion 15 is fitted into the through hole 5, with the small diameter surface 15b facing the small diameter hole 5b and the large diameter surface 15c facing the large diameter hole 5c.

[0017] The left clamping portion 7 is configured in the same manner as the right clamping portion 7, and so are given the same reference numerals with the left and right directions reversed. When each of the support parts 15, 15 is fitted into the through hole 5, the left clamp part 7 is supported by a fulcrum at "C" at the boundary between the side edge 9b and the side edge 11b, and the right clamp part 7 is supported by a fulcrum at "C" at the boundary between the side edge 9b and the side edge 11b, so that each of the clamp parts 7, 7 is rotatably held relative to the base 3. In this manner, the left and right clamp parts 7, 7 share a common fulcrum at "C." In addition, the base 3 is sandwiched between the step surface 15a of the support part 15 and the lower surface of the clamp part 7, and each of the support parts 15, 15 occupies more than half the space of the through hole 5, so that the clamp parts 7, 7 cannot be detached from the through hole 5. Additionally, side edge 9c and side edge 11c of clamp portion 7 are opposed surfaces sandwiching the letter "C."

[0018] The clamp portions 7, 7 are capable of rotating about a common fulcrum "C", but when the side edge 9b of the left clamp portion 7 and the side edge 9b of the right clamp portion 7 are brought together, further rotation in the direction of bringing the clamp portions together is prevented, and the same relationship exists between the side edge 11b of the left clamp portion 7 and the side edge 11b of the right clamp portion 7.

[0019] In order to restrict the rotation of the clamp portions 7, 7, a pair of restriction blocks 17, 17 are fixed to the upper surface 3a of the base table 3. The restriction block 17 is rectangular with its long side extending in the front-rear direction. The regulating block 17 is divided into an upper plate 19 and a lower plate 21. The lower plate 21 is shorter in width than the upper plate 19, and accordingly a step is formed on the inside in the left-right direction, and a groove 17a extends in the front-rear direction between the lower plate 21 and the upper surface 3a of the base stand 3. The restriction blocks 17, 17 are arranged with a gap in the left-right direction, and the left side portion of the front end face 17b of the right restriction block 17 is adjacent to the right side portion of the rear edge 9a of the right clamp portion 7 with a small clearance in the front-rear direction. In addition, the restriction block 17 has a thickness in the up-down direction and protrudes one step higher than the flat clamp portion 7.

[0020] Since the restricting block 17 is disposed as described above, the right clamp portion 7 is prevented from rotating in the counterclockwise direction from the position shown in Figures 1 to 3 by hitting the restricting block 17. The relationship between the left restricting block 17 and the left clamp portion 7 is similar, except that the positions are reversed.

[0021] A pressing piece 23 is disposed in the left-right gap between a pair of regulating blocks 17, 17. This pressing piece 23 forms a right-angled pentagon with two continuous right angles, and its area is divided into a square portion 25 and a triangular portion 27 including an acute angle, with the triangular portion 27 being the tip in the pressing direction. The left and right side edges 25a, 25a of the square portion 25, which face each other in parallel, are loosely fitted into the respective recessed grooves 17a, 17a of the regulating blocks 17, 17, and the acute apex angle 27a of the isosceles triangular portion 27 is sandwiched between the narrow edges 27b, 27b which face forward.

[0022] A substantially square recessed corner 31 is formed with narrow edges 27b, 27b as two edges. This recessed corner 31 is composed of an inner side surface 31a and an inner bottom surface 31b that stand in a "L" shape, and the inner side surface 31a forms a 45° "corner surface." The bend in this "L" shape is rounded. Furthermore, the inner bottom surface 31b is at the same height as the inner bottom surface 13c of the recessed groove portion 13. Furthermore, the length of the edge of the inner bottom surface 31b is the same as the width dimension of the inner bottom surface 13c of the recessed groove portion 13.

[0023] A reinforcing plate 29 is attached to the upper surface of the rear half of the square portion 25 of the pressing piece 23. The reinforcing plate 29 is rectangular in shape, and opposing short side edges 29a, 29a of the reinforcing plate 29 face the opposing surfaces of the upper plates 19, 19 of the pair of regulating blocks 17, 17. An extendable rod (not shown) of an electric cylinder is fixed to the rear end of the pressing piece 23, so that the pressing piece 23 can move forward and backward, and during movement, the left and right side edges 25a, 25a are guided and slid in the recessed grooves 17a, 17a of the regulating blocks 17, 17, respectively, and the short side edges 29a, 29a of the reinforcing plate 29 are guided and slid in contact with the opposing surfaces of the upper plates 19, 19 of the pair of regulating blocks 17, 17. Therefore, the movement trajectory is maintained constant. The forward end of the pressing piece 23 forms a recessed corner portion 31.

[0024] The edgewise bending device 1 is configured as described above, and when the strip X is set by fitting one sheet surface Xa into each of the concave grooves 13, 13 of the pair of clamping parts 7, 7 as shown in Figs. 1 to 3, the strip X is clamped at its middle part by the pair of clamping parts 7, 7 so that it can be bent in the edgewise direction. In this state, the strip X can be removed from the clamping parts 7, 7 by lifting it upward, but it is clamped to such an extent that it can be forced to bend in the edgewise direction. In this specification, "clamp" is used with this understanding. The strip X is loosely fitted into the groove 13 with a small gap therebetween.

[0025] The band plate X is straight with its longitudinal direction in the left-right direction, so that the pair of clamp portions 7, 7 have their respective groove portions 13, 13 lined up in series and their inner bottom surfaces 13c, 13c connected in a straight line, and the side edge 9b of the left clamp portion 7 and the side edge 9b of the left clamp portion 7 are joined together. From this state, when a thrust is applied to the pressing piece 23 to push it down and move it forward as shown by the arrow in Fig. 4(1), the pressing piece 23 enters the triangular gap 9e surrounded by the oblique edges 9d, 9d of the clamping parts 7, 7 with the apex angle 27a at the front, and the narrow edges 27b, 27b come into contact with the oblique edges 9d, 9d evenly on the left and right, exerting a force in the direction of opening the joint surfaces. Therefore, as shown by the arrow in Fig. 4(2), the pair of clamping parts 7, 7 rotate in opposite directions with "C" as a common fulcrum, that is, the left clamping part 7 rotates counterclockwise and the right clamping part 7 rotates clockwise at the same peripheral speed, and the side edge 9b of the left clamping part 7 and the side edge 9b of the right clamping part 7 gradually move away from the joint state in which the plate surfaces face the left and right directions. That is, the gap is formed by the fan-shaped expansion between the respective concave grooves 13, 13. During this process, the inner surfaces 13b, 13b rise from a state in which they were connected in a straight line into a mountain shape.

[0026] This gradually rising surface is the "corner surface," and the plate thickness surface Xb on one side of the edgewise direction of the strip X is pressed against this "corner surface" and bent, with this contact side becoming the bent inner surface. Moreover, the recessed corner portion 31 of the pressing piece 23 enters into the gap which expands in a fan shape. As shown in Figures 5 and 6, the pair of clamp portions 7, 7 rotate when the side edge 11b of the left clamp portion 7 and the side edge 11b of the right clamp portion 7 are in a palm-to-palm state with the plate surfaces facing left and right, and the "corner surface" ultimately becomes a surface bent at approximately 90°.

[0027] Furthermore, the gap that finally widens after the rotation is just the right size for recessed corner portion 31 to fit into, and recessed corner portion 31 enters and fits into that gap. Narrow edges 27b, 27b abut against the open end face of groove portion 13, and inner bottom surface 31b and inner bottom surface 13c, 13c are smoothly connected, and inner side surface 31a and inner side surface 13a, 13a are smoothly connected. In other words, recessed corner portion 31 and the pair of groove portions 13, 13 form an L-shaped continuous groove. The "corner surface" at this position abuts against and receives the plate thickness surface Xb on the other side in the edgewise direction of the strip X, thereby adjusting the uneven thickness. In other words, the pressing piece 23 also serves to receive and correct the portion that will become the outer bent surface.

[0028] In this edgewise bending device 1, the strip X is bent so that the middle part is folded by clamping both sides of the strip X and gradually changing the clamp angle in the folding direction of the strip X, and the inner surface of the bent part is pressed against the corners that gradually become sharper, so that the surface pressure at the center of the inner surface of the bent part gradually increases, preventing cracks and build-up around it. Moreover, the inner surface of the bent part sandwiching this part abuts against the inner surfaces 13a, 13a of the recessed groove part 13, so that the plastic flow causes the material to eventually flow into the inner bottom surface 31b of the recessed corner part 31 and be blocked. Therefore, the corners of the inner surface of the bent part and the corners of the outer surface of the bent part are both approximately right angles (=90°).

[0029] Although the embodiment of the present invention has been described in detail above, the specific configuration is not limited to this embodiment, and the invention also includes design changes within the scope of the present invention without departing from the gist of the present invention. For example, the above-mentioned edgewise bending device 1 is one example of a device devised for implementing the edgewise bending method, and the implementation of the edgewise bending method is not limited to those premised on the use of this device. In addition, the shape, size, and layout of each part of the edgewise bending device 1 are also optimally designed each time depending on the type, shape, size, etc. of the material. [Explanation of symbols]

[0030] 1…Edgewise bending device 3...Base stand 3a...Top surface 5...Through hole 5a...Step surface 5b...Small diameter hole 5c...Large diameter hole 7...Clamp section 7a...Top surface 9...Square piece 9a…Posterior margin 9b…Lateral margin 9c…Lateral margin 9d...Hypertension edge 9e...Triangular gap 11… Square piece, 11a… Front edge, 11b… Side edge 11c… Side edge, 13… Concave groove part, 13a… Inner surface 13b… Inner surface, 13c… Inner bottom surface, 15… Support part 15a… Step surface, 15b… Small-diameter surface, 15c… Large-diameter surface 17… Regulation block, 17a… Concave groove, 17b… Front end face 19… Upper plate, 21… Lower plate, 23… Pressing piece 25… Square corner part, 25a… Side edge, 27… Triangular part 27a… Apex angle, 27b… Clamping edge, 29… Reinforcing plate 29a… Short side edge, 31… Concave corner part, 31a… Inner surface 31b… Inner bottom surface X… Strip board, Xa… Board surface, Xb… Board thickness surface C… Rotation fulcrum

Claims

1. This edgewise bending method is characterized in that a plastically workable strip is clamped on both sides and the clamp angle is gradually changed in the folding direction of the strip, gradually increasing the surface pressure of the middle part, which will be the bending part, while bending the middle part in the edgewise direction.

2. 2. The edgewise bending method according to claim 1, This edgewise bending method is characterized in that the inner surface of the bent portion is formed by utilizing the changing clamp angle as a pressing surface.

3. The clamping device includes a pair of symmetrical clamping parts for clamping a plastically workable strip plate by fitting the strip plate into concave grooves arranged in series with an intermediate portion between them, and a rotating means for rotating the pair of clamping parts in opposite directions about a common fulcrum, An edgewise bending device characterized in that one side of the intermediate portion of the band plate is pressed against a corner surface of the groove portion which rises like a mountain as a gap is formed between the groove portions of the pair of clamping portions and as a result the groove portion is rotated to form a fan-shaped gap, thereby forming an inner bent surface and a bent outer surface on the other side.

4. 4. The edgewise bending apparatus according to claim 3, This edgewise bending device is characterized in that the clamp portion has opposing surfaces on both sides of the fulcrum, with the opposing surface on one side forming a corner surface of the groove portion, and when the respective groove portions of the pair of clamp portions extend straight and are connected, the opposing surfaces on the other side are brought together, and when the corner surfaces form the most acute angle, the opposing surfaces on the other side are opened.

5. 5. The edgewise bending apparatus according to claim 4, This edgewise bending device is characterized in that a symmetrical triangular gap is formed at the end where the opposing surfaces of one of the clamping sections are joined, and when a pressing piece having a triangular tip enters the gap, a force is applied in a direction extending from the apex of the triangle to the boundary between the joined opposing surfaces, causing the pair of clamping sections to rotate.

6. 6. The edgewise bending apparatus according to claim 5, The tip of the pressing piece has a recessed corner portion consisting of a corner surface and an inner bottom surface, Ultimately, as the clamp rotates, the space between the grooves of the pair of clamps expands in a fan shape, the inner bottom surface enters the gap, and a continuous L-shaped groove is formed between the corner and the pair of grooves, and the corner surface presses against the outer bent surface. This is an edgewise bending device characterized by the above.

7. In the edgewise bending apparatus according to any one of claims 3 to 6, An edgewise bending device characterized in that a support part having an arcuate circumferential surface is provided on the clamp part side and is rotatably fitted into a circular through hole that is provided in the base table and penetrates in the vertical direction, thereby enabling rotation of the clamp part.

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