Butt joint device and butt joint method

Abstract

To provide an abutment device that can inhibit a gap from generating between end edges of two members to abut on.SOLUTION: An abutment device 1 includes: a first clamp part 2 for clamping a first workpiece W1; a second clamp part 3 for clamping a second workpiece W2; and a drive part 4 for moving the first and second clamp parts 2, 3 in a direction of coming close to each other along a first direction D1. The first clamp part 2 is configured to clamp the first workpiece W1 with strong clamp force. The second clamp part 3 is configured to clamp the second workpiece W2 with weak clamp force. The drive part 4 is configured to move the first and second clamp parts 2, 3 in the direction of coming close to each other along the first direction D1 from a state where end edges W11, W21 of the first and second workpiece W1, W2 abut on each other in the first direction D1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a butting device and a butting method.

Background Art

[0002] Conventionally, in order to butt and weld two different members to each other, a tailored blank device as disclosed in Patent Document 1, for example, is used. The tailored blank device of Patent Document 1 includes a movable clamp that holds and is movable with respect to a first workpiece, a fixed clamp that holds and is fixed in position with respect to a second workpiece, and a driving means that moves the movable clamp with respect to the fixed clamp. In the tailored blank device of Patent Document 1, the first workpiece held by the movable clamp is abutted against the second workpiece held by the fixed clamp by moving the movable clamp by the driving means, and the butting portion between the first workpiece and the second workpiece is welded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The weldability when butting and welding two different members to each other is affected by the shape of the edges of either one or both of the members to be butted. For example, when the edges of both members to be butted have excellent linearity and are parallel to each other, almost no gap is generated in the butting portion between them, and excellent weldability can be obtained. However, if the linearity of the edges of either one or both of the members to be butted is poor, or if the edges of both members are not parallel to each other, a gap is generated in the butting portion between them, and there is a possibility that the expected weldability cannot be obtained.

[0005] The present invention aims to provide a butt joint device and a butt joint method that can suppress the occurrence of gaps between the butted edges of two members. [Means for solving the problem]

[0006] The butt joint device of the present invention is a butt joint device for butting the edge of a first work material and the edge of a second work material together in a first direction, wherein the butt joint device comprises a first clamping part for clamping the first work material, a second clamping part for clamping the second work material, and a drive unit for moving the first and second clamping parts, which are clamping the first and second work materials together, toward each other along the first direction in order to butt the edges of the first and second work materials together in the first direction, The clamping portion is configured to clamp the first workpiece with a strong clamping force, and this strong clamping force suppresses the sliding of the first workpiece against the first clamping portion until the edges of the first and second workpieces come into contact with each other as the first and second clamping portions, which are clamping the first and second workpieces, move toward each other along the first direction, and from the state in which the edges of the first and second workpieces come into contact with each other in the first direction, the first and second clamping portions move toward each other along the first direction. Even when moving, the clamping force is such that the sliding of the first workpiece against the first clamping portion is suppressed, and the second clamping portion is configured to clamp the second workpiece with a weak clamping force, and the weak clamping force suppresses the sliding of the second workpiece against the second clamping portion until the edges of the first and second workpieces come into contact with each other when the first and second clamping portions that clamp the first and second workpieces move toward each other along the first direction, and the edges of the first and second workpieces come into contact with each other. The clamping force is such that, when the first and second clamping portions move toward each other along the first direction from a state in which they are in contact in the first direction, the second workpiece material slides toward the second clamping portion, and the drive unit moves from a state in which the edge of the first workpiece material clamped by the first clamping portion with the strong clamping force and the edge of the second workpiece material clamped by the second clamping portion with the weak clamping force are in contact in the first direction, the first clamping portion that clamps the first workpiece material with the strong clamping force,The device is characterized by being configured to move the second clamping portion, which clamps the second workpiece with the weak clamping force, toward each other along the first direction.

[0007] Furthermore, the second clamping portion is configured to switch between the weak clamping force and the second strong clamping force. The second strong clamping force suppresses the sliding of the second workpiece against the second clamping portion until the edges of the first and second workpieces come into contact with each other when the first and second clamping portions, which clamp the first and second workpieces, move toward each other along the first direction. From the state where the edges of the first and second workpieces come into contact in the first direction, the first and second clamping portions move toward each other along the first direction. The clamping force is such that even when moved, it suppresses the sliding of the second workpiece against the second clamping portion, and it is preferable that the drive unit is configured to move the first clamping portion, which clamps the first workpiece with the strong clamping force, and the second clamping portion, which clamps the second workpiece with the second strong clamping force, in a direction toward each other along the first direction, from a state in which the edge of the first workpiece clamped by the first clamping portion with the strong clamping force and the edge of the second workpiece clamped by the second clamping portion with the second strong clamping force are in contact in the first direction.

[0008] Furthermore, it is preferable that the butt joint device includes a control unit for controlling the clamping force of the first and second clamping sections, and a gap detection unit for detecting the gap between the edge of the first workpiece and the edge of the second workpiece, and that when the gap detection unit detects a gap of a predetermined size or larger between the edge of the first workpiece and the edge of the second workpiece while the edges of the first and second workpieces are butted together, the control unit switches the clamping force of the second clamping section from the weak clamping force to the second strong clamping force.

[0009] The present invention relates to a butt joint method for butting the edge of a first workpiece and the edge of a second workpiece together in a first direction using a butt joint device, wherein the butt joint device comprises a first clamping portion for clamping the first workpiece, a second clamping portion for clamping the second workpiece, and a drive unit for moving the first and second clamping portions, which are clamping the first and second workpieces, toward each other along the first direction in order to butt the edges of the first and second workpieces together in the first direction, The fitting method includes the steps of: clamping the first workpiece with the first clamping portion; clamping the second workpiece with the second clamping portion; and using the drive unit to move the first clamping portion that clamped the first workpiece and the second clamping portion that clamped the second workpiece, from a state in which the edge of the first workpiece clamped with the first clamping portion and the edge of the second workpiece clamped with the second clamping portion are in contact in the first direction, in a direction toward each other along the first direction. Furthermore, in the step of clamping the first workpiece with the first clamping portion, the first workpiece is clamped with a strong clamping force by the first clamping portion, and this strong clamping force suppresses the sliding of the first workpiece with respect to the first clamping portion until the edges of the first and second workpieces come into contact with each other as the first and second clamping portions, which are clamping the first and second workpieces, move toward each other along the first direction, and from the state in which the edges of the first and second workpieces come into contact in the first direction, the first and A clamping force that suppresses sliding of the first workpiece against the first clamping portion even when the second clamping portion moves toward each other along the first direction, wherein in the process of clamping the second workpiece with the second clamping portion, the second workpiece is clamped with a weak clamping force by the second clamping portion, and this weak clamping force lasts until the edges of the first and second workpieces come into contact with each other as the first and second clamping portions, which clamp the first and second workpieces, move toward each other along the first direction.The clamping force is characterized by suppressing the sliding of the second workpiece material against the second clamping portion, and allowing sliding of the second workpiece material against the second clamping portion when the first and second clamping portions move toward each other along the first direction, starting from a state where the edges of the first and second workpiece materials are in contact with each other in the first direction.

[0010] Furthermore, in the step of clamping the second workpiece with the second clamping portion, it is preferable that the clamping force of the second clamping portion is switched from the weak clamping force to a second strong clamping force, and the second workpiece is clamped with the second strong clamping force by the second clamping portion, and that the second strong clamping force is such that, as the first and second clamping portions that clamp the first and second workpieces move toward each other along the first direction, the sliding of the second workpiece with respect to the second clamping portion is suppressed until the edges of the first and second workpieces come into contact with each other, and that even after the edges of the first and second workpieces come into contact in the first direction, the sliding of the second workpiece with respect to the second clamping portion is suppressed even when the first and second clamping portions move toward each other along the first direction.

[0011] Furthermore, it is preferable to include a step of switching the clamping force of the second clamping section from the weak clamping force to the second strong clamping force when there is a gap of a predetermined size or larger between the edge of the first workpiece and the edge of the second workpiece while the edges of the first and second workpieces are abutting against each other. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a butt joint device and a butt joint method that can suppress the occurrence of a gap between the butted edges of two members. [Brief explanation of the drawing]

[0013] [Figure 1]This is a schematic side view illustrating a tailored blank manufacturing apparatus equipped with a butt joint device according to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic top view showing the tailored blank manufacturing apparatus. [Figure 3] Figure 1 is an explanatory diagram illustrating the positioning operation in which the first and second workpieces are positioned relative to each other in the tailored blank manufacturing apparatus, where (a) shows the state before positioning, (b) shows the state after positioning, and (c) shows the state after positioning. [Figure 4] Figure 1 is an explanatory diagram for schematicly illustrating the butt joint operation in the tailored blank manufacturing apparatus shown, in which the first and second workpieces are butted together by a butt joint device. (a) shows the state in which the first and second workpieces are clamped by the first and second clamping parts, (b) shows the state in which the first and second workpieces are moved closer to each other by the first and second clamping parts, (c) shows the state in which the first and second workpieces are butted together by the first and second clamping parts, and (d) shows the state in which the first and second workpieces, which have been butted together and welded, have been transported to the welding inspection device. [Figure 5] This is a top view of the first and second workpieces joined together by a butt joint device according to one embodiment of the present invention. [Figure 6] This is a top view of the first and second workpieces joined together by a butt joint device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0014] A butt joint device and butt joint method according to one embodiment of the present invention will be described below with reference to the attached drawings. However, the embodiments shown below are examples only, and the butt joint device and butt joint method of the present invention are not limited to the following examples.

[0015] The butt joint device 1 and butt joint method of this embodiment are used to butt the edge W11 of a first workpiece W1 and the edge W21 of a second workpiece W2 in a first direction D1, as shown in Figure 1. Below, the butt joint device 1 and butt joint method of this embodiment will be described with an example of application to a tailored blank manufacturing apparatus TWB that produces tailored welded blanks (TWB) obtained by joining different types of workpieces together. However, the butt joint device and butt joint method of the present invention are not limited to the tailored blank manufacturing apparatus TWB and can be applied to other applications where it is necessary to butt the edges of two workpieces together while suppressing the occurrence of gaps between the edges of the two workpieces.

[0016] In this specification, the first direction D1 is shown as the horizontal direction, the second direction D2 which is substantially perpendicular to the first direction D1 is shown as the vertical direction, and the third direction D3 is shown as a direction substantially perpendicular to both the first and second directions D1 and D2. However, the first, second and third directions D1, D2 and D3 only need to be substantially orthogonal to each other, and for example, the first and second directions D1 and D2 may be inclined from the horizontal and vertical directions, respectively.

[0017] The tailored blank manufacturing apparatus TWB is an apparatus that butt-welds the edges W11 and W21 of different types of workpieces W1 and W2 to join different types of workpieces W1 and W2 together. The workpieces W1 and W2 joined together by the tailored blank manufacturing apparatus TWB are weldable plate-shaped members having a length in the first direction D1, a plate thickness in the second direction D2, and a width in the third direction D3. For example, they are steel plates such as cold-rolled steel plates and surface-treated steel plates. In particular, the tailored blank manufacturing apparatus TWB is preferably used to join two steel plates having different lengths, widths, plate thicknesses, materials, surface treatment layers, etc. However, the tailored blank manufacturing apparatus TWB is not limited to the meaning of the term "tailored blank", and can be applied to joining other workpieces other than steel plates as long as the workpieces can butt-weld their edges together and be joined to each other.

[0018] As shown in FIG. , the tailored blank manufacturing apparatus TWB includes a butting device 1 that butts the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 against each other, conveying devices T1 and T2 for conveying the first workpiece W1 and the second workpiece W2 to / from the butting device 1, a positioning device PP for positioning the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 relative to each other, and a welding machine WM for welding the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 to each other. The tailored blank manufacturing apparatus TWB further includes a welding inspection apparatus that also functions as a gap detection unit ⑥ of the butting device 1 described later.

[0019] The conveying devices T1 and T2 convey the first and second workpieces W1 and W2 along the first direction D1. As shown in Figures 1 and 2, the conveying devices T1 and T2 consist of a first conveying device T1 located on one side of the first direction D1 (right side in Figures 1 and 2) and a second conveying device T2 located on the other side of the first direction D1 (left side in Figures 1 and 2), flanking the butt joint device 1, positioning device PP, and welding machine WM. The first and second conveying devices T1 and T2 are spaced apart from each other in the first direction D1, and the butt joint device 1, positioning device PP, and welding machine WM are installed within that space. The first and second conveying devices T1 and T2 are not particularly limited as long as they can convey the first and second workpieces W1 and W2, and can be implemented as belt conveyors.

[0020] The first and second conveying devices T1 and T2 are positioned relative to each other such that their respective conveying surfaces (the surfaces that support the first and second workpieces W1 and W2) are substantially flush with each other. Furthermore, the first and second conveying devices T1 and T2 are positioned such that their respective conveying surfaces are substantially flush with the clamping surfaces (the surfaces that contact the first and second workpieces W1 and W2) on the other side (lower side in Figure 1) of the clamping portions 2 and 3 of the butt joint device 1, which will be described later, in the second direction D2. This facilitates the transfer of the first and second workpieces W1 and W2 between the first and second conveying devices T1 and T2 and the butt joint device 1.

[0021] Here, an example of the conveying operations of the first and second workpieces W1 and W2 by the first and second conveying devices T1 and T2 will be described. First, by the second conveying device T2, both the first and second workpieces W1 and W2 are conveyed from the other side (left side in the figure) to the one side (right side in the figure) in the first direction D1 with the first workpiece W1 located on one side in the first direction D1 (right side in the figure) of the second workpiece W2. When the end of the first workpiece W1 on one side in the first direction D1 advances beyond the butting device 1 to the one side in the first direction D1, while the second workpiece W2 is being conveyed to the one side in the first direction D1 by the second conveying device T2, the first workpiece W1 is conveyed to the one side in the first direction D1 by the first conveying device T1 instead of the second conveying device T2. When the first and second workpieces W1 and W2 are respectively arranged on one side and the other side in the first direction D1 sandwiching the butting device 1, the conveyance of the first and second workpieces W1 and W2 to the one side in the first direction D1 by the first and second conveying devices T1 and T2 is stopped (the states in FIGS. 1 and 2). Next, in order to bring the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 closer to each other, the first workpiece W1 is conveyed to the other side in the first direction D1 by the first conveying device T1, and the second workpiece W2 is conveyed to the one side in the first direction D1 by the second conveying device T2. The edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 that are brought closer to each other are welded to each other by the welding machine WM after being positioned by the positioning device PP and butted by the butting device 1. Finally, the first and second workpieces W1 and W2 that are welded and joined together are conveyed to the one side in the first direction D1 by the first and second conveying devices T1 and T2. The first and second workpieces W1 and W2 joined together are conveyed by the first and second conveying devices T1 and T2 so that the welded portion between the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 is located at the inspection position of the welding inspection device (gap detection unit s6) (see FIG. 4(d)), and after the welding inspection is completed, it is further conveyed to the one side in the first direction D1.

[0022] The positioning device PP works in cooperation with the transport devices T1 and T2 to position the edges W11 of the first workpiece W1 and W21 of the second workpiece W2 relative to each other so that a predetermined gap L (see Figures 3(b) and (c)) is provided between the edges W11 of the first workpiece W1 and W21 of the second workpiece W2. The positioning device PP includes a positioning member PP1 that is movable between a position within the gap between the edges W11 of the first workpiece W1 and W21 of the second workpiece W2 (positioning position, see Figures 3(a) and (b)) and a position separated from the gap between the edges W11 of the first workpiece W1 and W21 of the second workpiece W2 (release position, see Figure 3(c)). In the examples shown in Figures 1 and 2, the positioning member PP1 is shown as a plurality of rods extending along a second direction D2 and aligned along a third direction D3. The positioning device PP further includes a moving mechanism PP2 for moving the positioning member PP1 between a positioning position and a release position. In the example shown in Figures 3(a) to (c), the moving mechanism PP2 is configured to move the positioning member PP1 between the positioning position and the release position along a second direction D2.

[0023] When positioning the edges W11 and W21 of the first and second workpieces W1 and W2 relative to each other, the positioning device PP positions the positioning member PP1 at the positioning position, and the first and second transport devices T1 and T2 transport the first and second workpieces W1 and W2 such that the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 approach each other in the first direction D1 toward the positioning member PP1 (from the state in Figure 3(a) to the state in Figure 3(b)). When the edges W11 and W21 of the first and second workpieces W1 and W2 both come into contact with the positioning member PP1, the transport of the first and second workpieces W1 and W2 is stopped, and a predetermined gap L is formed between the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 (see Figure 3(b)). At this time, as shown in Figure 2, the multiple positioning members PP1 have approximately the same length (diameter in the illustrated example) in the first direction D1 and are arranged in a substantially straight line along the third direction D3, so that the edges W11 and W21 of the first and second workpieces W1 and W2 are positioned substantially parallel to each other along the multiple positioning members PP1. When the positioning operation is completed in this way and the edges W11 and W21 of the first and second workpieces W1 and W2 are brought together by the butt joint device 1 in a subsequent step, the positioning members PP1 are moved from the positioning position to the release position by the moving mechanism PP2 (see Figure 3(c)).

[0024] The butt joint device 1 butts the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 together in a first direction D1. In this embodiment, the butt joint device 1 brings the edges W11 and W21 of the first and second workpieces W1 and W2, which have been positioned by the conveying devices T1 and T2 and the positioning device PP so that there is a predetermined distance L between them, closer together along the first direction D1 and butts them together. However, when the butt joint device 1 butts the edges W11 and W21 of the first and second workpieces W1 and W2 together, it is sufficient that the edges W11 and W21 of the first and second workpieces W1 and W2 are in close proximity to each other in the first direction D1, and it is not necessarily required that they have been positioned in advance to have a predetermined distance L between them. Details of the butt joint device 1 will be described later.

[0025] The welding machine WM welds the edges W11 of the first workpiece W1 and the edge W21 of the second workpiece W2, which have been butted together by the butt joint device 1, to each other. The welding machine WM includes a known laser device WM1 and a moving mechanism (not shown) that moves the laser device WM1 along the direction in which the edges W11 and W21 of the first and second workpieces W1 and W2 extend (a third direction D3, see Figure 2). The welding machine WM welds the edges W11 and W21 of the first and second workpieces W1 and W2 to each other by irradiating the edges W11 and W21 of the first and second workpieces W1 and W2 with laser light while moving the laser device WM1 along the third direction D3 using the moving mechanism.

[0026] The welding inspection device (gap detection unit 6) inspects the welded portions of the edges W11 and W21 of the first and second workpiece materials W1 and W2 welded by the welding machine WM. The welding inspection device (gap detection unit 6) includes a laser device (not shown) that irradiates the welded portion with laser light and receives the reflected light reflected from the welded portion, and a calculation unit (not shown) that calculates the profile of the welded portion based on the round-trip time of the laser light. Based on the profile of the welded portion, the welding inspection device (gap detection unit 6) can determine the presence or absence of pinholes and the presence or absence of weld bead depressions (underfill) that occur when the edges W11 and W21 of the first and second workpiece materials W1 and W2 are welded together with a wide gap between them. For example, by determining the size of pinholes and underfill, the welding inspection device (gap detection unit 6) can also estimate the size of the gap that existed between the edges W11 and W21 of the first and second workpiece materials W1 and W2 before welding. In this embodiment, the welding inspection device (gap detection unit 6) is positioned on one side (right side in the figures) of the first direction D1 from the butt joint device 1 and the welding machine WM, as shown in Figures 1 and 2. After the edges W11 and W21 of the first and second workpieces W1 and W2 are welded together, the welded portion is positioned by the transport devices T1 and T2 to a position corresponding to the welding inspection device (gap detection unit 6) (see Figure 4(d)), and the welded portion is inspected by the welding inspection device (gap detection unit 6).

[0027] Next, the butt joint device 1 will be described. As shown in Figures 1 and 2, the butt joint device 1 includes a first clamping section 2 for clamping a first workpiece W1, a second clamping section 3 for clamping a second workpiece W2, and a drive section 4 that moves the first and second clamping sections 2 and 3, which are clamping the first and second workpieces W1 and W2, toward each other along a first direction D1. In this embodiment, the butt joint device 1 further includes a control section 5 that controls the clamping force of the first and second clamping sections 2 and 3.

[0028] In this embodiment, the first clamping unit 2 is driven by a drive device 23 (see Figure 1) which is communicatively connected to the control unit 5 in order to clamp the first workpiece W1. The first clamping unit 2 is configured so that the clamping force is controlled (adjusted) by the control unit 5, and is configured to be able to transition between a clamped state in which the first workpiece W1 is clamped (see Figures 4(a) to (c)) and an unclamped state in which the first workpiece W1 is not clamped (see Figure 4(d)) under the control of the control unit 5. However, the first clamping unit 2 only needs to be able to clamp the first workpiece W1, and may clamp the first workpiece W1 by other means such as manual drive, or may be configured so that the clamping force is adjustable by other means such as manual drive.

[0029] The first clamping portion 2 only needs to be able to clamp the first workpiece W1, and the direction in which the first workpiece W1 is clamped is not particularly limited. In this embodiment, as shown in Figure 4(a), the first clamping portion 2 is configured to clamp the first workpiece W1 from a second direction D2 which is substantially perpendicular to the first direction D1. To this end, as shown in Figure 1, the first clamping portion 2 comprises a one-side clamping member 21 positioned on one side (upper side in the figure) of the second direction D2, and a other-side clamping member 22 positioned on the other side (lower side in the figure) of the second direction D2, sandwiching the first workpiece W1. The first clamping portion 2 clamps the first workpiece W1 from the second direction D2 between the clamping surface of the one-side clamping member 21 (the surface on the other side of the second direction D2) and the clamping surface of the other-side clamping member 22 (the surface on the one side of the second direction D2) as the one-side clamping member 21 and the other-side clamping member 22 approach each other in the second direction D2. In this embodiment, the other-side clamping member 22 is fixed, and the one-side clamping member 21 is configured to move along the second direction D2 relative to the other-side clamping member 22. However, the one-side clamping member 21 may be fixed, and the other-side clamping member 22 may be configured to move along the second direction D2 relative to the one-side clamping member 21, or both the one-side and other-side clamping members 21 and 22 may be movable along the second direction D2 and configured to move along the second direction D2 relative to each other. The first clamping portion 2 may be configured to clamp the first workpiece W1 from a direction inclined from the second direction D2, depending on the shape of the first workpiece W1.

[0030] The first clamp portion 2 is positioned relative to the second clamp portion 3 such that when the edge W11 of the first workpiece W1 clamped by the first clamp portion 2 and the edge W21 of the second workpiece W2 clamped by the second clamp portion 3 are brought closer to each other along the first direction D1, they abut (come into contact) with each other. In this embodiment, as shown in Figures 1 and 2, the first clamp portion 2 is positioned in a location corresponding to the second clamp portion 3 in the second direction D2 and the third direction D3. More specifically, with respect to the second direction D2, the first clamp portion 2 is positioned such that the clamp surface of the first clamp portion 2 on the other side (lower side in Figure 1) of the first clamp portion 2 (the clamp surface of the other side clamp member 22) is substantially flush with the clamp surface of the second clamp portion 3 on the other side of the second direction D2 (the clamp surface of the other side clamp member 32, described later) in the second direction D2. This allows the edges W11 and W21 of the first and second workpieces W1 and W2 to be butted together so that the other surfaces of the first and second workpieces W1 and W2 in the second direction D2 are substantially flush with each other. Furthermore, as described above, the first clamp portion 2 is positioned in a position corresponding to the second clamp portion 3 with respect to the third direction D3, but it may also be configured to be movable along the third direction D3 in order to align one of the edges of the first and second workpieces W1 and W2 in the third direction D3.

[0031] The first clamping portion 2 is configured to be relatively movable relative to the second clamping portion 3 along a first direction D1 by a drive unit 4 while the first workpiece material W1 is clamped. By moving the first clamping portion 2 closer to the second clamping portion 3 along the first direction D1 by the drive unit 4, the edges W11 and W21 of the first and second workpiece materials W1 and W2, which are clamped by the first and second clamping portions 2 and 3 respectively, come into contact with each other. In this embodiment, the first clamping portion 2 is fixed and the second clamping portion 3 is configured to be movable relative to the first clamping portion 2 along the first direction D1. However, conversely, the second clamping portion 3 may be fixed and the first clamping portion 2 may be movable, or both the first and second clamping portions 2 and 3 may be movable.

[0032] The first clamping section 2 is configured to clamp the first workpiece W1 with a strong clamping force. Here, "strong clamping force" is a clamping force that, when the edges W11 and W21 of the first and second workpieces W1 and W2 are brought together, prevents the first workpiece W1 from moving relative to the first clamping section 2 in the first direction D1 (and third direction D3) even when the first workpiece W1 is subjected to a load from the second workpiece W2 in the first direction D1 (and third direction D3). In other words, the "strong clamping force" is a clamping force that suppresses the sliding of the first workpiece W1 against the first clamping part 2 until the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact with each other when the first and second clamping parts 2 and 3, which clamp the first and second workpieces W1 and W2, move toward each other along the first direction D1. From the state where the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact along the first direction D1, the clamping force continues to suppress the sliding of the first workpiece W1 against the first clamping part 2 even when the first and second clamping parts 2 and 3 move toward each other along the first direction D1. The first clamping section 2 firmly holds the first workpiece W1 by clamping it with a strong clamping force, so that even when the first workpiece W1 is subjected to a load from the second workpiece W2 when the edges W11 and W21 of the first and second workpieces W1 and W2 are brought together, relative movement of the first workpiece W1 with respect to the first clamping section 2 is suppressed. The strong clamping force is not particularly limited as long as it is set according to the frictional force between the first clamping section 2 and the first workpiece W1 as described above, and can be set to a range of 4 to 10 MPa, specifically 5 MPa.

[0033] In this embodiment, the second clamping section 3 is driven by a drive device 33 (see Figure 1) which is communicatively connected to the control unit 5 in order to clamp the second workpiece W2. The second clamping section 3 is configured so that the clamping force is controlled (adjusted) by the control unit 5, and is configured to be able to transition between a clamped state in which the second workpiece W2 is clamped (see Figures 4(a) to (c)) and an unclamped state in which the second workpiece W2 is not clamped (see Figure 4(d)) under the control of the control unit 5. However, the second clamping section 3 only needs to be able to clamp the second workpiece W2, and may be driven by other methods such as manual operation to clamp the second workpiece W2, or may be configured so that the clamping force is adjustable by other methods such as manual operation.

[0034] The second clamping portion 3 only needs to be able to clamp the second workpiece W2, and the direction in which the second workpiece W2 is clamped is not particularly limited. In this embodiment, as shown in Figure 4(a), the second clamping portion 3 is configured to clamp the second workpiece W2 from a second direction D2 which is substantially perpendicular to the first direction D1. To this end, as shown in Figure 1, the second clamping portion 3 comprises a one-side clamping member 31 positioned on one side (upper side in the figure) of the second direction D2, and a other-side clamping member 32 positioned on the other side (lower side in the figure) of the second direction D2, sandwiching the second workpiece W2. The second clamping portion 3 clamps the second workpiece W2 from the second direction D2 between the clamping surface of the one-side clamping member 31 (the surface on the other side of the second direction D2) and the clamping surface of the other-side clamping member 32 (the surface on the one side of the second direction D2) as the one-side clamping member 31 and the other-side clamping member 32 approach each other in the second direction D2. In this embodiment, the other-side clamping member 32 is fixed, and the one-side clamping member 31 is configured to move along the second direction D2 relative to the other-side clamping member 32. However, the one-side clamping member 31 may be fixed, and the other-side clamping member 32 may be configured to move along the second direction D2 relative to the one-side clamping member 31, or both the one-side and other-side clamping members 31 and 32 may be movable along the second direction D2 and configured to move along the second direction D2 relative to each other. The second clamping portion 3 may be configured to clamp the second workpiece W2 from a direction inclined from the second direction D2, depending on the shape of the second workpiece W2.

[0035] The second clamp portion 3 is positioned relative to the first clamp portion 2 such that when the edge W21 of the second workpiece W2 clamped by the second clamp portion 3 and the edge W11 of the first workpiece W1 clamped by the first clamp portion 2 are brought closer to each other in the first direction D1, they abut (come into contact) with each other. In this embodiment, as shown in Figures 1 and 2, the second clamp portion 3 is positioned in a position corresponding to the first clamp portion 2 in the second direction D2 and the third direction D3. More specifically, with respect to the second direction D2, the second clamp portion 3 is positioned such that the clamp surface of the second clamp portion 3 on the other side (lower side in Figure 1) in the second direction D2 (the clamp surface of the other side clamp member 32) is substantially flush with the clamp surface of the first clamp portion 2 on the other side in the second direction D2 (the clamp surface of the other side clamp member 22) in the second direction D2. This allows the edges W11 and W21 of the first and second workpieces W1 and W2 to be butted together so that the other surfaces of the first and second workpieces W1 and W2 in the second direction D2 are substantially flush with each other. Furthermore, as described above, the second clamp portion 3 is positioned in a position corresponding to the second clamp portion 3 with respect to the third direction D3, but it may also be configured to be movable along the third direction D3 in order to align one of the edges of the first and second workpieces W1 and W2 in the third direction D3.

[0036] The second clamping portion 3 is configured to be relatively movable relative to the first clamping portion 2 along the first direction D1 by the drive unit 4 while the second workpiece W2 is clamped. By moving the second clamping portion 3 closer to the first clamping portion 2 along the first direction D1 by the drive unit 4, the edges W11 and W21 of the first and second workpieces W1 and W2, which are clamped by the first and second clamping portions 2 and 3 respectively, come into contact with each other. As described above, in this embodiment, the first clamping portion 2 is fixed and the second clamping portion 3 is configured to be movable relative to the first clamping portion 2 along the first direction D1. However, conversely, the second clamping portion 3 may be fixed and the first clamping portion 2 may be movable, or both the first and second clamping portions 2 and 3 may be movable.

[0037] The second clamping section 3 is configured to clamp the second workpiece W2 with a weak clamping force. Here, "weak clamping force" is a clamping force that allows the second workpiece W2 to move relative to the second clamping section 3 in the first direction D1 (and third direction D3) when the edges W11 and W21 of the first and second workpieces W1 and W2 are brought together and the second workpiece W2 is subjected to a load from the first workpiece W1 in the first direction D1 (and third direction D3). In other words, the "weak clamping force" is a clamping force that suppresses the sliding of the second workpiece W2 against the second clamping part 3 until the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact with each other when the first and second clamping parts 2 and 3, which clamp the first and second workpieces W1 and W2, move toward each other along the first direction D1. From the state where the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact along the first direction D1, the first and second clamping parts 2 and 3 move toward each other along the first direction D1, and then allows the sliding of the second workpiece W2 against the second clamping part 3. The second clamping section 3 clamps the second workpiece W2 with a weak clamping force, thereby moving the second workpiece W2 relative to the first workpiece W1 so that the edges W11 and W21 of the first and second workpieces W1 and W2 fit together (reducing the gap between them) when the edges W11 and W21 of the first and second workpieces W1 and W2 abut each other. The weak clamping force is not particularly limited as long as it is set according to the frictional force between the second clamping section 3 and the second workpiece W2 as described above, and can be set to a range of 0.1 to 3 MPa, specifically 1 MPa.

[0038] The second clamping section 3 may be configured to switch the clamping force between a weak clamping force and a second strong clamping force. The clamping force of the second clamping section 3 may be switched by, for example, the control unit 5, or by other means such as manual operation. Here, "second strong clamping force" is a clamping force that, when the edges W11 and W21 of the first and second workpieces W1 and W2 are brought together, prevents the second workpiece W2 from moving relative to the second clamping section 3 in the first direction D1 (and third direction D3) even when the second workpiece W2 is subjected to a load from the first workpiece W1 in the first direction D1 (and third direction D3). In other words, the "second strong clamping force" is a clamping force that suppresses the sliding of the second workpiece W2 against the second clamping part 3 until the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact with each other when the first and second clamping parts 2 and 3, which clamp the first and second workpieces W1 and W2, move toward each other along the first direction D1. From the state where the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact along the first direction D1, the clamping force continues to suppress the sliding of the second workpiece W2 against the second clamping part 3 even when the first and second clamping parts 2 and 3 move toward each other along the first direction D1. The second clamping section 3 clamps the second workpiece W2 with a second strong clamping force, causing the edge W21 of the second workpiece W2 to abut against the edge W11 of the first workpiece W1, which is clamped with a strong clamping force by the first clamping section 2. This allows one or both of the edges W11 and W21 of the first and second workpieces W1 and W2 to fit together (reducing the gap between them). The second strong clamping force is not particularly limited, as long as it is set according to the frictional force between the second clamping section 3 and the second workpiece W2 as described above. It may be the same as or different from the strong clamping force of the first clamping section 2, and can be set in the range of 4 to 10 MPa, specifically 5 MPa.

[0039] The drive unit 4 moves the first and second clamping parts 2 and 3, which clamp the first and second workpieces W1 and W2, in a direction toward each other along the first direction D1 in order to butt the edges W11 and W21 of the first and second workpieces W1 and W2 together in the first direction D1. The drive unit 4 is configured to move the first clamping part 2, which clamps the first workpiece W1 with a strong clamping force, and the second clamping part 3, which clamps the second workpiece W2 with a weak clamping force, in a direction toward each other along the first direction D1, starting from a state in which the edge W11 of the first workpiece W1, which is clamped with a strong clamping force by the first clamping part 2, and the edge W21 of the second workpiece W2, which is clamped with a weak clamping force by the second clamping part 3, are in contact in the first direction D1. As a result, the butt joint device 1 of this embodiment can obtain the following effects. For example, as shown in Figure 5, even if the edges W11 and W21 of the first and second workpieces W1 and W2 are brought into contact with each other by the conveying devices T1 and T2 and the positioning device PP in the tailored blank manufacturing apparatus TWB before being brought into contact with each other by the butt joint device 1, the edges W11 of the first workpiece W1 and W21 of the second workpiece W2 may be slightly inclined relative to each other (see the solid line in Figure 5; Figure 5 illustrates the workpieces with a greater inclination than the actual inclination to make the inclination easier to understand). In such a case, even if the edges W11 and W21 of the first and second workpieces W1 and W2 come into contact in the first direction D1, a gap will still remain between them. In such a case, the drive unit 4 drives the first and second clamping units 2 and 3 as described above, causing the second workpiece W2 to slide against the second clamping unit 3 so that the edges W11 and W21 of the first and second workpieces W1 and W2 are substantially parallel to each other, and to move (rotate in the illustrated example) in a plane including the first and third directions D1 and D3 relative to the first workpiece W1 (see the dashed line in Figure 5). This allows the edges W11 and W21 of the first and second workpieces W1 and W2 to abut each other so that they fit together (the gap between them is reduced).Therefore, according to the butt joint device 1 of this embodiment, it is possible to suppress the occurrence of gaps between the butt edges W11 and W21 of the two workpiece materials W1 and W2.

[0040] In this case, the drive unit 4 may be configured to stop the relative movement of the first and second clamping units 2 and 3 when the first and second clamping units 2 and 3 have moved a predetermined distance closer than the state in which the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact with each other. For example, as described above, when the conveying devices T1 and T2 and the positioning device PP in the tailored blank manufacturing apparatus TWB clamp the first and second workpieces W1 and W2 with the first and second clamping units 2 and 3, starting from a state in which the edges W11 and W21 of the first and second workpieces W1 and W2 are separated by a predetermined distance L in a first direction D1, and move the first and second workpieces W1 and W2 toward each other, the drive unit 4 can be configured to move the first and second clamping units 2 and 3 toward each other by a distance equal to the predetermined distance L plus a predetermined distance. The butt joint device 1 can be operated safely by setting the timing (corresponding to a predetermined distance) at which the relative movement of the first and second clamping parts 2 and 3 stops within a range where the first and second clamping parts 2 and 3 do not collide with each other.

[0041] The drive unit 4 may be configured to move the first clamp unit 2, which clamps the first workpiece W1 with a strong clamping force, and the second clamp unit 3, which clamps the second workpiece W2 with a second strong clamping force, toward each other along the first direction D1, when the clamping force of the second clamp unit 3 has been switched from a weak clamping force to a second strong clamping force, and the edge W11 of the first workpiece W1 clamped with a strong clamping force by the first clamp unit 2 and the edge W21 of the second workpiece W2 clamped with a second strong clamping force by the second clamp unit 3 are in contact in the first direction D1. As a result, the butt joint device 1 of this embodiment can obtain the following effects. For example, as shown in Figure 6, one or both of the edges W11 and W21 of the first and second workpieces W1 and W2 may be curved or have burrs or sagging, resulting in a gap between them even when the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact with each other (see the solid line in Figure 6; Figure 6 illustrates the workpieces with a greater curvature than the actual curvature to make the curvature of the edges easier to understand). In such a case, the drive unit 4 drives the first and second clamp units 2 and 3 as described above, causing one or both of the edges W11 and W21 of the first and second workpiece materials W1 and W2 to plastically deform so that they fit together (reducing the gap between them), thereby bringing the edges W11 and W21 of the first and second workpiece materials W1 and W2 together (see the dashed line in Figure 6). Therefore, according to the butt joint device 1 of this embodiment, it is possible to suppress the occurrence of a gap between the butt joint edges W11 and W21 of the two workpiece materials W1 and W2.

[0042] In this case, the drive unit 4 may be configured to stop the relative movement of the first and second clamping parts 2 and 3 when a load exceeding a predetermined level is applied when the first and second clamping parts 2 and 3 are moved relative to each other from a state in which the edges W11 and W21 of the first and second workpiece materials W1 and W2 are in contact with each other. This suppresses excessive plastic deformation of the edges W11 and W21 of the first and second workpiece materials W1 and W2, avoids collisions between the first and second clamping parts 2 and 3, and allows the butt joint device 1 to operate safely. However, notwithstanding the above, the drive unit 4 may be configured to stop the relative movement of the first and second clamping parts 2 and 3 when the first and second clamping parts 2 and 3 have moved a predetermined distance closer to each other from a state in which the edges W11 and W21 of the first and second workpiece materials W1 and W2 are in contact with each other.

[0043] The control unit 5 is communicatively connected to the drive devices 23 and 33 that drive the clamping operation of the first and second clamp units 2 and 3, and controls the clamping force of the first and second clamp units 2 and 3 by controlling the driving force of the drive devices 23 and 33. For example, the control unit 5 is configured to switch the clamping force of the second clamp unit 3 from a weak clamping force to a second strong clamping force when the gap detection unit 6, described later, detects a gap of a predetermined size or larger between the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 when the edges W11 and W21 of the first and second workpiece materials W1 and W2 are butted together (in contact). The predetermined size or larger is not particularly limited and can be set appropriately according to the required butt joint quality. For example, the predetermined size or larger can be set appropriately according to whether the strength and water permeability of the welded part when welded with a gap of that size in place are within an acceptable range, and specifically, it can be 50 μm or larger. The control unit 5 is configured to switch the clamping force of the second clamping unit 3 when such a gap is detected. In this embodiment, if the gap between the edges W11 and W21 of the first and second workpieces W1 and W2 cannot be sufficiently eliminated by the abutting action of the edges W11 and W21 of the first and second workpieces W1 and W2 while the second clamping unit 3 is clamping the second workpiece W2 with a weak clamping force, the control unit 5 switches the clamping force of the second clamping unit 3 from a weak clamping force to a second strong clamping force. This causes plastic deformation of one or both of the edges W11 and W21 of the first and second workpieces W1 and W2, more reliably suppressing the formation of a gap between the edges W11 and W21 of the first and second workpieces W1 and W2. In this embodiment, the switching of the clamping force of the second clamping unit 3 is performed by the control unit 5, but it may also be performed by other methods such as manual operation.

[0044] The control unit 5 can switch the clamping force of the second clamping unit 3 at various timings. In this embodiment, if, based on the inspection results after butt welding of the first and second workpieces W1 and W2, it is estimated that there was a gap of a predetermined size or larger between the edges W11 and W21 of the first and second workpieces W1 and W2 when they were butted together before welding, the clamping force of the second clamping unit 3 is switched during the butt welding operation of the first and second workpieces W1 and W2 that will be butted together later. For example, when multiple workpieces W1 and W2 are cut under the same conditions (for example, with the same cutting tool), the shapes of the edges W11 and W21 of the workpieces W1 and W2 are often almost the same. When multiple workpieces W1 and W2 with almost the same edge shape W11 and W21 are butt welded together, the state of the welded part is almost reproduced. Therefore, if the welded portions of the previously butt-welded workpieces W1 and W2 do not meet the predetermined conditions, the butt-welding conditions of the later butt-welded workpieces W1 and W2 can be changed to prevent gaps from forming between the edges W11 and W21 of the workpieces W1 and W2 that are cut under the same conditions and then butt-welded.

[0045] The switching of the clamping force of the second clamping section 3 may be performed before welding, based on the state of the butt joint of the workpieces W1 and W2 before butt welding, rather than being performed at the time of the butt joint operation of the workpieces W1 and W2 based on the state of the butt joint after butt welding, as in this embodiment. For example, as will be described later, the gap detection section 6 can be configured to detect the gap between the edges W11 and W21 of the first and second workpieces W1 and W2 when their edges W11 and W21 are butted together (before welding). In this way, for example, when the edges W11 and W21 of the first and second workpieces W1 and W2 are butted together while the second clamping section 3 is clamping the second workpiece W2 with a weak clamping force, the gap detection section 6 can detect the gap between the edges W11 and W21. If a gap of a predetermined size or larger is detected between the edges W11 and W21, the clamping force of the second clamping section 3 is switched from a weak clamping force to a strong clamping force, and the butt joint operation is performed again.

[0046] The control unit 5 may also be configured to be communicatively connected to the drive unit 4 and to control the movement of the first and second clamping parts 2 and 3 in the first direction D1, as described above, by controlling the drive operation of the drive unit 4. For example, the control unit 5 controls the drive unit 4 to move the first and second clamping parts 2 and 3 relative to each other from a state where the edges W11 and W21 of the first and second workpiece materials W1 and W2 clamped by the first and second clamping parts 2 and 3 are in contact with each other, so that the first and second clamping parts 2 and 3 move closer to each other by a predetermined distance along the first direction D1. Furthermore, when the control unit 5 moves the first and second clamping parts 2 and 3 relative to each other from a state where the edges W11 and W21 of the first and second workpiece materials W1 and W2 clamped by the first and second clamping parts 2 and 3 are in contact with each other, the control unit 5 controls the drive unit 4 to stop the relative movement of the first and second clamping parts 2 and 3 when the drive unit 4 receives a load exceeding a predetermined level. However, the movement of the first and second clamping portions 2 and 3 in the first direction D1 only needs to be performed by the drive unit 4, and may be performed by controlling the drive operation of the drive unit 4 by other means, such as manually.

[0047] The butt joint device 1 may further include the gap detection unit 6 described above. The gap detection unit 6 detects the gap between the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 when the edges W11 and W21 of the first and second workpieces W1 and W2 are butted together. Here, "detecting the gap" between the edges W11 and W21 includes not only detecting the gap between the edges W11 and W21 before or after welding, or both, after the edges W11 and W21 of the first and second workpieces W1 and W2 are butted together, but also estimating the gap between the edges W11 and W21 when the edges W11 and W21 are butted together before welding, based on the state of the welded portion after welding.

[0048] In this embodiment, the gap detection unit 6 is implemented as a welding inspection device, as described above. The gap detection unit 6 detects pinholes, underfill, etc., from the profiles of the welded portions of the edges W11, W21 of the first and second workpiece materials W1, W2, and detects the gap between the edges W11, W21 after welding. Furthermore, by determining the size of the pinholes, underfill, etc., in the welded portion, the gap detection unit 6 can estimate the size of the gap that existed between the edges W11, W21 of the first and second workpiece materials W1, W2 before welding. In this embodiment, the gap detection unit 6 is implemented as a welding inspection device that inspects the welded portion after welding, but it is not limited to this embodiment, and may be positioned between the first clamp portion 2 and the second clamp portion 3, and configured to detect the gap between the edges W11, W21 of the first and second workpiece materials W1, W2 when they are butted together (pre-welding state).

[0049] Next, the butt joint method of this embodiment will be described. The butt joint method of this embodiment is a method for butting the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 in a first direction D1 using the butt joint device 1 described above. The following describes several steps included in the butt joint method, but each step may be carried out in the order described below, or in a different order.

[0050] The butt joint method may optionally include a preparatory step before butting the edges W11 and W21 of the first and second workpieces W1 and W2 together, as shown in Figures 3(a) to (c), in which the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2 are positioned relative to each other in a first direction D1 with a predetermined distance L between them. At this time, it is preferable that the edges W11 and W21 of the first and second workpieces W1 and W2 are substantially parallel to each other along a third direction D3. The step of positioning the edges W11 and W21 of the first and second workpieces W1 and W2 relative to each other can be performed using the conveying devices T1 and T2 and the positioning device PP described above. First, as shown in Figure 3(a), the positioning member PP1 of the positioning device PP is positioned at a position (positioning position) between the edge W11 of the first work material W1, which is positioned on one side of the first direction D1 (right side in the figure), and the edge W21 of the second work material W2, which is positioned on the other side of the first direction D1 (left side in the figure), with the butt joint device 1 in between. Next, as shown in Figure 3(b), the first and second work materials W1 and W2 are transported by the first and second transport devices T1 and T2, respectively, so that their respective edges W11 and W21 move closer to each other in the first direction D1 toward the positioning member PP1. When the edges W11 and W21 of the first and second work materials W1 and W2 both come into contact with the positioning member PP1, the transport of the first and second work materials W1 and W2 is stopped, and a predetermined gap L is formed between the edges W11 and W21. After forming a predetermined gap L between the edges W11 and W21 of the first and second workpieces W1 and W2, the positioning member PP1 is moved to a position separated from the positioning position (positioning release position), as shown in Figure 3(c). Note that the step of positioning the edges W11 and W21 of the first and second workpieces W1 and W2 relative to each other is not limited to the example described above, and may be performed by other methods such as manual operation instead of using the transport devices T1 and T2 and the positioning device PP.

[0051] The butt joint method, as shown in Figure 4(a), includes the steps of clamping the first workpiece W1 with the first clamping section 2 and clamping the second workpiece W2 with the second clamping section 3. In this embodiment, the first and second workpieces W1 and W2 are clamped by the first and second clamping sections 2 and 3, respectively, using drive devices 23 and 33 controlled by the control unit 5. More specifically, the first and second workpieces W1 and W2 are clamped from the second direction D2 by moving the clamping members 21 and 31 on one side of the first and second clamping sections 2 and 3, respectively, and the clamping members 22 and 32 on the other side of the first and second clamping sections 2 and 3, respectively, relative to each other along the second direction D2 in a direction approaching each other in the second direction D2. The step of clamping the first and second workpieces W1 and W2 with the first and second clamping parts 2 and 3 is not limited to the example described above, and may be performed by other methods such as manual operation instead of using the drive devices 23 and 33.

[0052] The butt joint method includes the step of using a drive unit 4 to move the first and second clamping parts 2 and 3, which clamp the first and second workpieces W1 and W2, in a direction toward each other along the first direction D1, in order to butt the edges W11 and W21 of the first and second workpieces W1 and W2 together in a first direction D1, as shown in Figure 4(b). The butt joint method also includes the step of using the drive unit 4 to move the first clamping part 2, which clamps the first workpiece W1, and the second clamping part 3, which clamps the second workpiece W2, in a direction toward each other along the first direction D1, from a state in which the edge W11 of the first workpiece W1 clamped by the first clamping part 2 and the edge W21 of the second workpiece W2 clamped by the second clamping part 3 are in contact in the first direction D1, as shown in Figure 4(c). This allows the edges W11 and W21 of the first and second workpieces W1 and W2 to be butted together in the first direction D1.

[0053] In the butt joint method, in the step of clamping the first workpiece W1 with the first clamping part 2, the first clamping part 2 clamps the first workpiece W1 with the strong clamping force described above, and in the step of clamping the second workpiece W2 with the second clamping part 3, the second clamping part 3 clamps the second workpiece W2 with the weak clamping force described above. Then, in the step of moving the first and second clamping parts 2 and 3 relative to each other, the drive unit 4 moves the first clamping part 2, which clamps the first workpiece W1 with a strong clamping force, and the second clamping part 3, which clamps the second workpiece W2 with a weak clamping force, from a state where the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact with each other, in a direction toward each other along the first direction D1. As a result, as described above, even if the edges W11 and W21 of the first and second workpieces W1 and W2 are slightly inclined relative to each other (see the solid line in Figure 5), the second workpiece W2 slides against the second clamp portion 3 so that its edges W11 and W21 become approximately parallel to each other, and moves (rotational movement in the illustrated example) in a plane including the first and third directions D1 and D3 relative to the first workpiece W1 (see the dashed line in Figure 5). By bringing the edges W11 and W21 of the first and second workpieces W1 and W2 together in this way, it is possible to suppress the formation of a gap between the abutting edges W11 and W21 of the two workpieces W1 and W2.

[0054] In this butt joint method, the relative movement of the first and second clamping parts 2 and 3 may be stopped when the first and second clamping parts 2 and 3 have moved a predetermined distance closer than the first and second workpiece materials W1 and W2, after the edges W11 and W21 of the first and second workpiece materials W1 and W2 are in contact with each other. For example, if the edges W11 and W21 of the first and second workpiece materials W1 and W2 are positioned relative to each other with a predetermined distance L between them before butting them together, the first and second clamping parts 2 and 3 may be moved relative to each other by a predetermined distance equal to the predetermined distance L. By setting the timing for stopping the relative movement of the first and second clamping parts 2 and 3 (corresponding to the predetermined distance) within a range where the first and second clamping parts 2 and 3 do not collide, the butt joint device 1 can be operated safely.

[0055] In the butt joint method, in the step of clamping the second workpiece W2 with the second clamping portion 3, the clamping force of the second clamping portion 3 may be switched from the weak clamping force described above to the second strong clamping force described above, and the second workpiece W2 may be clamped with the second strong clamping force by the second clamping portion 3. In this case, in the step of moving the first and second clamping portions 2 and 3 relative to each other, the control unit 5 moves the first clamping portion 2, which is clamping the first workpiece W1 with a strong clamping force, and the second clamping portion 3, which is clamping the second workpiece W2 with a second strong clamping force, from a state where the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact with each other, in a direction toward each other along the first direction D1. As a result, as described above, even if, for example, one or both of the edges W11 and W21 of the first and second workpieces W1 and W2 are curved (see solid line in Figure 6), or have burrs or sagging, one or both of the edges W11 and W21 of the first and second workpieces W1 and W2 will plastically deform so that they fit together (reduce the gap between them) (see dashed line in Figure 6). By butting the edges W11 and W21 of the first and second workpieces W1 and W2 together in this way, it is possible to more reliably suppress the occurrence of gaps between the butted edges W11 and W21 of the two workpieces W1 and W2.

[0056] In this butt joint method, when the first and second clamping parts 2 and 3 are moved relative to each other from a state where the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact, the relative movement of the first and second clamping parts 2 and 3 may be stopped when the drive unit 4 receives a load exceeding a predetermined level. This suppresses excessive plastic deformation of the edges W11 and W21 of the first and second workpieces W1 and W2, avoids collisions between the first and second clamping parts 2 and 3, and allows the butt joint device 1 to operate safely. However, notwithstanding the above, the relative movement of the first and second clamping parts 2 and 3 may be stopped when the first and second clamping parts 2 and 3 have moved a predetermined distance closer to each other from a state where the edges W11 and W21 of the first and second workpieces W1 and W2 are in contact.

[0057] The switching of the clamping force of the second clamping section 3 described above can be performed, for example, when the edges W11 and W21 of the first and second workpieces W1 and W2 are butted together and there is a gap of a predetermined size or larger between the edge W11 of the first workpiece W1 and the edge W21 of the second workpiece W2. In other words, the butting method may include a step of switching the clamping force of the second clamping section 3 from a weak clamping force to a second strong clamping force when there is a gap of a predetermined size or larger between the edges W11 and W21 of the first and second workpieces W1 and W2. As a result, when the second clamping section 3 clamps the second workpiece W2 with a weak clamping force, if the butting action of the edges W11 and W21 of the first and second workpieces W1 and W2 does not sufficiently eliminate the gap between the edges W11 and W21, switching the clamping force of the second clamping section 3 from a weak clamping force to a second strong clamping force will cause plastic deformation of one or both of the edges W11 and W21 of the first and second workpieces W1 and W2, thereby more reliably suppressing the formation of a gap between the edges W11 and W21 of the first and second workpieces W1 and W2.

[0058] The gap between the edges W11 and W21 of the first and second workpieces W1 and W2 can be detected either before or after welding, or both, after the edges W11 and W21 are butted together. Alternatively, the gap between the edges W11 and W21 before welding, when the edges W11 and W21 are butted together, can be estimated from the state of the welded portion after welding, as detected by the gap detection unit 6. In this embodiment, as shown in Figure 4(d), after welding the edges W11 and W21 of the first and second workpieces W1 and W2, the welded portion is positioned at a location corresponding to the gap detection unit 6, and the welded portion is inspected by the gap detection unit 6. The gap detection unit 6 then estimates the gap between the edges W11 and W21 before welding, when the edges W11 and W21 are butted together, from the state of the welded portion after welding.

[0059] The clamping force of the second clamp section 3 can be switched at various timings. In this embodiment, if, based on the inspection results after butt welding of the first and second workpiece materials W1 and W2, it is estimated that there was a gap of a predetermined size or larger between the edges W11 and W21 when their edges were butted together before welding, the clamping force of the second clamp section 3 is switched during the butt welding operation of the first and second workpiece materials W1 and W2 that will be butted together later. As a result, as described above, if the welded portion of the previously butt-welded workpiece materials W1 and W2 does not meet the predetermined conditions, the butt welding conditions of the workpiece materials W1 and W2 to be butt-welded later can be changed to suppress the occurrence of a gap between the edges W11 and W21 of the workpiece materials W1 and W2 that will be butt-welded later.

[0060] The clamping force of the second clamping section 3 may be switched before butt welding, based on the state of the butt joint of the workpieces W1 and W2 before butt welding. For example, when the edges W11 and W21 of the first and second workpieces W1 and W2 are butted together with the second clamping section 3 clamping the second workpiece W2 with a weak clamping force, the gap detection section 6 may detect the gap between the edges W11 and W21. If a gap of a predetermined size or larger is detected between the edges W11 and W21, the clamping force of the second clamping section 3 is switched from a weak clamping force to a strong clamping force, and the butt joint operation is performed again. This can suppress the occurrence of welding defects. [Explanation of Symbols]

[0061] 1. Butt joint device 2. First clamp section 21 One-sided clamping member 22 Other side clamp member 23 Drive unit 3. Second clamp section 31 One-sided clamping member 32 Other side clamp member 33 Drive unit 4. Drive Unit 5. Control Unit 6. Gap detection unit D1 First direction D2 Second direction D3 Third direction L predetermined interval PP positioning device PP1 Positioning Member PP2 movement mechanism T1 First conveying device T2 Second conveying device TWB Tailored Blank Manufacturing Machine W1 First workpiece W11 Edge of the first workpiece W2 Second workpiece W21 Edge of the second workpiece WM Welding Machine WM1 Laser Device

Claims

1. A butt joint device for butting the edges of a first workpiece and a second workpiece together in a first direction, wherein the butt joint device is A first clamping portion for clamping the first workpiece, A second clamping portion for clamping the second workpiece, A drive unit moves the first and second clamping portions, which clamp the first and second workpieces, toward each other along the first direction in order to bring the edges of the first and second workpieces toward each other in the first direction. Equipped with, The first clamping portion is configured to clamp the first workpiece with a strong clamping force, and the strong clamping force is such that, as the first and second clamping portions clamping the first and second workpieces move toward each other along the first direction, the clamping force suppresses the sliding of the first workpiece relative to the first clamping portion until the edges of the first and second workpieces come into contact with each other, and even after the edges of the first and second workpieces come into contact in the first direction, the clamping force suppresses the sliding of the first workpiece relative to the first clamping portion even when the first and second clamping portions move toward each other along the first direction. The second clamping portion is configured to clamp the second workpiece with a weak clamping force, and this weak clamping force is such that, as the first and second clamping portions clamping the first and second workpieces move toward each other along the first direction, the sliding of the second workpiece relative to the second clamping portion is suppressed until the edges of the first and second workpieces come into contact with each other, and from the state in which the edges of the first and second workpieces come into contact in the first direction, the sliding of the second workpiece relative to the second clamping portion is permitted when the first and second clamping portions move toward each other along the first direction. The drive unit is configured to move the first clamping portion, which clamps the first workpiece with the strong clamping force, and the second clamping portion, which clamps the second workpiece with the weak clamping force, from a state in which the edge of the first workpiece clamped by the first clamping portion with the strong clamping force and the edge of the second workpiece clamped by the second clamping portion with the weak clamping force are in contact in the first direction, toward each other along the first direction. The second clamping portion is configured to switch between a weak clamping force and a second strong clamping force, wherein the second strong clamping force is a clamping force that suppresses the sliding of the second workpiece against the second clamping portion until the edges of the first and second workpieces come into contact with each other when the first and second clamping portions, which clamp the first and second workpieces, move toward each other along the first direction, and continues to suppress the sliding of the second workpiece against the second clamping portion even when the first and second clamping portions move toward each other along the first direction from the state in which the edges of the first and second workpieces come into contact in the first direction. The drive unit is configured to move the first clamping portion, which clamps the first workpiece with the strong clamping force, and the second clamping portion, which clamps the second workpiece with the second strong clamping force, from a state in which the edge of the first workpiece clamped by the first clamping portion with the strong clamping force and the edge of the second workpiece clamped by the second clamping portion with the second strong clamping force are in contact in the first direction, toward each other along the first direction. The aforementioned butt joint device, A control unit for controlling the clamping force of the first and second clamping sections, A gap detection unit for detecting the gap between the edge of the first workpiece and the edge of the second workpiece, Equipped with, When the gap detection unit detects a gap of a predetermined size or larger between the edge of the first workpiece and the edge of the second workpiece while the edges of the first and second workpieces are abutting against each other, the control unit is configured to switch the clamping force of the second clamping unit from the weak clamping force to the second strong clamping force. Butt joint device.

2. A butt joint method for butting the edges of a first workpiece and a second workpiece together in a first direction using a butt joint device, The aforementioned butt joint device, A first clamping portion for clamping the first workpiece, A second clamping portion for clamping the second workpiece, A drive unit moves the first and second clamping portions, which clamp the first and second workpieces, toward each other along the first direction in order to bring the edges of the first and second workpieces toward each other in the first direction. Equipped with, The aforementioned butt joint method is The first step is to clamp the first workpiece with the first clamping portion, The process involves clamping the second workpiece with the second clamping portion, The drive unit moves the first clamping portion that clamps the first workpiece and the second clamping portion that clamps the second workpiece, from a state in which the edge of the first workpiece clamped by the first clamping portion and the edge of the second workpiece clamped by the second clamping portion are in contact in the first direction, toward each other along the first direction. Includes, In the step of clamping the first workpiece with the first clamping portion, the first workpiece is clamped with a strong clamping force by the first clamping portion, and this strong clamping force is such that, as the first and second clamping portions that clamp the first and second workpieces move toward each other along the first direction, the sliding of the first workpiece with respect to the first clamping portion is suppressed until the edges of the first and second workpieces come into contact with each other, and from the state in which the edges of the first and second workpieces come into contact in the first direction, the sliding of the first workpiece with respect to the first clamping portion is suppressed even when the first and second clamping portions move toward each other along the first direction. In the step of clamping the second workpiece with the second clamping portion, the second workpiece is clamped with a weak clamping force, and this weak clamping force is such that, as the first and second clamping portions that clamp the first and second workpieces move toward each other along the first direction, the sliding of the second workpiece with respect to the second clamping portion is suppressed until the edges of the first and second workpieces come into contact with each other, and from the state in which the edges of the first and second workpieces come into contact in the first direction, the sliding of the second workpiece with respect to the second clamping portion is permitted when the first and second clamping portions move toward each other along the first direction. In the step of clamping the second workpiece with the second clamping portion, the clamping force of the second clamping portion is switched from the weak clamping force to the second strong clamping force, and the second workpiece is clamped with the second strong clamping force by the second clamping portion, the second strong clamping force is a clamping force that suppresses the sliding of the second workpiece with respect to the second clamping portion until the edges of the first and second workpieces come into contact with each other as the first and second clamping portions, which clamp the first and second workpieces, move toward each other along the first direction, and from the state in which the edges of the first and second workpieces come into contact in the first direction, even if the first and second clamping portions move toward each other along the first direction, the sliding of the second workpiece with respect to the second clamping portion is suppressed. The process includes a step of switching the clamping force of the second clamping section from the weak clamping force to the second strong clamping force when the edges of the first and second workpieces are abutted together and there is a gap of a predetermined size or larger between the edge of the first workpiece and the edge of the second workpiece, Butt joint method.

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