Method for manufacturing a steel door

Abstract

To provide a steel door body 1 which is surely connected even when it is thick with plate thickness of 1.6 mm, in forming an abutted part X of surface and rear surface plates 7, 8 by welding them by laser beam irradiation.SOLUTION: Welding of an abutted part X is performed while allowing laser beam irradiation to perform wobbling movement in the two-dimensional direction which is a circular arc-shape crossing a connection line when the abutted part X is made to be the connection line. Thereby, a laser-welded door body 1 is provided in which plate thickness is as thick as 1.6 mm.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to the technical field of a manufacturing method of a fabricated door provided at an entrance of a building such as a house or a building. Steel

Background Art

[0002] Generally, a door body may be provided at the entrance of this type of building so as to be openable and closable. A steel door configured by integrally connecting a pair of front and back plates made of a steel material (for example, a galvanized steel sheet) is known. When manufacturing such a door body, the connecting portion where the front and back plates are to be connected is a portion where the edge portions are butted or laminated. Conventionally, these connecting portions have been connected by welding such as arc welding or sputter welding. However, when such welding is performed, the welded portion is exposed to high heat, which not only causes thermal distortion in the door body, but also causes unevenness due to welding marks and welding sags. Therefore, there is a problem that further work such as repairing these is required and the workability is poor. Therefore, a method has been proposed in which a laser beam is irradiated onto these connecting portions for welding (fusion bonding) to avoid the occurrence of thermal distortion and unevenness due to welding (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By forming the door body using the laser beam, it has become possible to efficiently manufacture a highly accurate steel door. However, in the case of using the laser beam, the dot-shaped laser beam simply moves linearly along the welding line. In addition to the narrow irradiation width, the energy irradiated may also be small. For example, when welding the butting parts of the front and back plates, if there is a gap at the butting part, the gap part will become hollow and will not be welded. To avoid this, the front and back plates must be bent into a special shape so that there is no gap at the welding part, which not only deteriorates the workability, but also the thicker the plate thickness of the front and back plates, the more difficult such bending processing itself becomes. As a result, when forming the door body using the conventional laser beam, there are problems such as it can only be manufactured as a thin-walled one with almost no gap between the connecting parts, and these are the problems to be solved by the present invention.

Means for Solving the Problems

[0005] The present invention was created for the purpose of solving these problems in view of the above circumstances. The invention according to claim 1 is a method for manufacturing a steel door having an irradiation step of welding a door body with front and back plates made of steel plates by irradiating a connecting portion between the front and back plates with a laser beam. In the method, the connecting portion between the front and back plates is a linear connecting line, and the irradiation in the irradiation step of the laser beam includes irradiation by two-dimensional wobbling movement that moves the connecting line while moving in the width direction across the connecting line. The connecting line is provided so that its start end or end reaches the edge of the front and back plates perpendicular to the connecting line. The welding in the irradiation step is performed with a gap from the start end or end of the connecting line. It is a method for manufacturing a steel door characterized by this. plate The invention according to claim 2 is a method for manufacturing a steel door having an irradiation step of welding a door body with front and back plates made of steel plates by irradiating a connecting portion between the front and back plates with a laser beam. In the method, the connecting portion between the front and back plates is a linear connecting line, and the irradiation in the irradiation step of the laser beam includes irradiation by two-dimensional wobbling movement that moves the connecting line while moving in the width direction across the connecting line. The connecting line is provided so that its start end or end reaches the edge of the front and back plates perpendicular to the connecting line. The welding in the irradiation step is performed with a gap from the start end or end of the connecting line. It is a method for manufacturing a steel door characterized by this. The invention according to claim 2 is a method for manufacturing a steel door having an irradiation step of welding a door body with front and back plates made of steel plates by irradiating a connecting portion between the front and back plates with a laser beam. In the method, the connecting portion between the front and back plates is a linear connecting line, and the irradiation in the irradiation step of the laser beam includes irradiation by two-dimensional wobbling movement that moves the connecting line while moving in the width direction across the connecting line. The connecting line is provided so that its start end or end reaches the edge of the front and back plates perpendicular to the connecting line. The welding in the irradiation step is performed with a gap from the start end or end of the connecting line. It is a method for manufacturing a steel door characterized by this. plateThe connecting part between the two is a linear connecting line, and the irradiation in the irradiation process of the laser beam includes irradiation by two-dimensional wobbling movement that moves the connecting line while moving in the width direction across the connecting line. The connecting line is provided so that the start or end reaches the corner of the front and back plates orthogonal to the connecting line. The welding in the irradiation process is characterized in that it is performed with a gap from the start or end of the connecting line. This is a method for manufacturing a steel door. The invention according to claim 3 is a method for manufacturing a steel door according to claim 1 or 2, characterized in that the gap from the start or end of the connecting line until the laser beam irradiation is 3 to 7 mm. The invention according to claim 4 is such that the connecting part between the front and back plates is a butting part where the edges of the bent piece parts that are bent from the front and back surfaces of the front and back plates to face each other and constitute the edge part of the door body are butted against each other. At this butting part, the side piece part of the bent piece part of the frame member provided with a pair of side piece parts on the front and back surface sides that abut against the front and back surfaces abuts. The part where the irradiation by the wobbling movement of the laser beam is performed is the butting part of the part where the side piece part of the bent piece part abuts. This is a method for manufacturing a steel door according to any one of claims 1 to 3. The invention according to claim 5 is a method for manufacturing a steel door according to claim 4, characterized in that the welding by the laser beam irradiation between the butting parts is welding in a state where it does not reach through the side piece part of the bent piece part. The invention according to claim 6 is a method for manufacturing a steel door according to claim 4 or 5, characterized in that the welding by the laser beam irradiation between the butting parts is welding up to the bent piece part that does not reach the side piece part of the bent piece part. The invention according to claim 7 is a method for manufacturing a steel door according to any one of claims 4 to 6, characterized in that the moving width in the width direction across the connecting line of the laser beam irradiation between the butting parts is in the range of 50% to 200% with respect to the plate thickness of the front and back plates. The invention according to claim 8 is a method for manufacturing a steel door according to any one of claims 1 to 7, characterized in that the plate thickness of the front and back plates is 1.2 mm to 2.0 mm.

Advantages of the Invention

[0006] By adopting the invention of claim 1, since the irradiation of the laser beam is by wobbling movement, it results in planar irradiation and a large amount of energy by the irradiation. When forming a steel door body, when connecting the front and back facing materials by welding, even if there is a gap at the connecting part, a steel door that is surely welded can be efficiently manufactured. In this case, when the connecting part is a linear one formed by butting the edges of the front and back plates against each other, efficient laser beam irradiation is performed by wobbling movement that moves the connecting line while moving in the width direction across the connecting line. As a result, a steel door with the connecting line reliably welded can be efficiently manufactured. Further, when the start or end of the connecting line is the edge of the front and back plates orthogonal to the connecting line, the edge will not be welded by laser beam irradiation. As a result, the edge will be maintained in its original state without welding, and the edge part will not be deformed and damage the appearance. By adopting the invention of claim 2, Since the irradiation of the laser beam is by wobbling movement, it becomes a planar irradiation and the amount of energy by the irradiation also becomes large. When forming a steel door body and connecting the front and back surface materials by welding, even if there is a gap at the connecting part, a steel door reliably welded can be efficiently manufactured. In this case, when the connecting part is a linear one formed by butting the edges of the front and back plates against each other, efficient laser beam irradiation is performed by wobbling movement that moves the connecting line while moving in the width direction across the connecting line. As a result, a steel door with the connecting line reliably welded can be efficiently manufactured. Further, when the start or end of the connecting line is the corner of the front and back plates orthogonal to the connecting line, the corner will not be welded by laser beam irradiation. As a result, the corner will be maintained in its original state without welding, and the corner part will not be deformed and damage the appearance. By adopting the invention of claim 3, Since the interval from the start or end of the connecting line to the start of laser beam irradiation is 3 to 7 mm, it is possible to avoid a decrease in the connecting strength while maintaining the shape of the edge or corner of the front and back plates orthogonal to the connecting line. 。 Claim 4 By adopting the invention of [claim number], the connecting part where the laser beam irradiation by wobbling movement is performed becomes the butting part between the edge parts of the bent piece parts actively formed on the front and back facing plates. However, since the side piece part of the bent piece part of the framing member installed inside the door body is in a butting state, welding by laser beam irradiation is performed in a state reinforced by the framing member. Claim 5 By adopting the invention of [claim number], when welding the butting part between the edge parts, since the welding by the laser beam does not penetrate the side piece part of the bent piece part, it is possible to avoid the deformation of the framing member that occurs when welding through the framing member, and thus a highly accurate steel door can be efficiently manufactured. Claim 6 By adopting the invention of [claim number], furthermore, when welding the edge parts of the bent piece parts, since the welding by the laser beam only welds the bent piece parts without reaching the side piece part of the bent piece part, at the welding part between the front and back facing materials, the framing member will not be deformed by welding or the like. As a result, a highly accurate steel door can be efficiently manufactured. Claim 7 By adopting the invention of [claim number], welding by laser beam irradiation with wobbling movement according to the plate thickness of the front and back facing plates can be performed. Claim 8 By adopting the invention of [claim number], in the case where the plate thickness of the front and back facing plates is a thickness of 1.2 mm to 2.0 mm, a highly accurate and strong steel door welded by laser beam irradiation can be provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a door body (panel body) constituting a steel door, and the door body 1 is pivotally attached to a door frame 3 via a hinge 2 so as to be openable and closable. Further, the door body 1 is provided with a handle 4, a locking device 5, and a door closer (self-closing device) 6, all of which are the same as those in the prior art.

[0009] The door body 1 is formed in a box shape using front and rear plates 7 and 8 made of a steel plate (for example, a galvanized steel plate), and a frame member 9 is interposed between the front and rear plates 7 and 8. The connection between the front and rear plates 7 and 8 and the connection between the front and rear plates 7 and 8 and the frame member 9 are performed using welding (fusion welding) based on the irradiation of a laser beam. In this case, the irradiation position of the laser beam is wobbling movement in the two-dimensional direction of the x-y direction while performing welding by laser beam irradiation. Hereinafter, these will be described in detail.

[0010] The front and rear plates 7 and 8 are formed with front and rear plate portions 7a and 8a, and bent piece portions 7b, 8b, 7e, and 8e that are bent in the front-rear direction so that the left and right edge portions and the upper edge portion face each other from the front and rear plate portions 7a and 8a. A frame member 9 is interposed between the front and rear plate portions 7a and 8a. The bent piece portions 7b, 8b, 7e, and 8e are in contact portions X where their edge portions abut against each other, and the contact portion X is set on a linear connection line R.

[0011] As the frame member 9, a horizontal upper frame member 9U and a lower frame member 9D provided at the upper and lower edge portions of the door body 1, vertical door tip side and door butt side (hanging side) frame members 9S and 9J provided at the left and right edge portions, and a vertical intermediate frame member 9M disposed between the upper and lower frame members 9U and 9D with a left-right gap between the door tip side and door butt side frame members 9S and 9J are provided. In the present embodiment, all of these frame members 9 are U-shaped, but it goes without saying that a shape commonly adopted such as an L-shape can be appropriately adopted as the frame member 9.

[0012] As described above, the aggregate 9 in this embodiment is formed in a U-shape, comprising front and rear leg pieces 9a and a cross piece 9b between the two leg pieces 9a. The upper and lower side aggregates 9U and 9D are incorporated into the door body 1 with the lower side open and the cross piece 9b positioned on the upper side. The head and tail side aggregates 9S and 9J are incorporated into the door body 1 with the inner side in the left-right direction open and the cross piece 9b positioned on the outer side. On the other hand, for the intermediate aggregate 9M, similar to the above-mentioned aggregates 9, the two leg pieces 9a are in contact with the front and rear surface parts 7a and 8a. For the cross piece 9b, it is possible to arbitrarily select a specification where all face the head side or the tail side, or a specification where a part faces the head side and the rest faces the tail side.

[0013] In the aggregate 9 incorporated in this way, all the leg pieces 9a constitute a pair of front and rear surface part side pieces that are in contact with the front and rear surface parts 7a and 8a of the front and rear panels 7 and 8. In contrast, for the cross piece 9b, the cross pieces 9b of the head and tail side aggregates 9S and 9J are in contact with the bent pieces 7b and 8b bent from the left and right edge parts of the front and rear surface parts 7a and 8a of the front and rear panels 7 and 8, and the cross piece 9b of the upper aggregate 9U is in contact with the bent pieces 7e and 8e bent from the upper edge parts of the front and rear surface parts 7a and 8a, constituting bent piece side pieces. However, the front and rear panels 7 and 8 do not contact the cross piece 9b of the intermediate aggregate 9M.

[0014] More specifically, regarding the butt side aggregate 9J, the half part 2a of the door body on the hinge side 2 is fixed via screws 2b, while regarding the door tip side aggregate 9S, a notch 9c for fitting and incorporating a lock case (not shown) in which a handle device 4 for operating a latch (not shown) for locking to protrude and retract and a lock device 5 for operating a dead bolt (not shown) for locking to protrude and retract are incorporated as a set is provided in the cross piece part 9b together with notches 7d, 8d provided in the bent piece parts 7b, 8b of the front and back face plates 7, 8. However, the notch 9c provided in the cross piece part 9b is narrower in the vertical direction than the notches 7d, 8d provided in the bent piece parts 7b, 8b, and the edge part on the notch part 9c side of the cross piece part 9b is exposed, and the handle 4 and the lock device 5 are assembled to this exposed edge part. In addition, attachment holes 7f, 7g, 8f, 8g for penetratingly incorporating the lock device 5 and the handle device 4 are formed in the front and back face plates 7, 8.

[0015] And as described above, the front and back face plates 7, 8 of the present embodiment are formed with bent piece parts 7b, 8b in which both left and right edge parts are bent inward in the front and back direction, and bent piece parts 7e, 8e in which both upper and lower edge parts are bent inward in the front and back direction. As a result, the door tip side, the butt side, and the upper side aggregates 9U, 9D, 9U are covered by the corresponding bent piece parts 7b, 8b, 7e, 8e and are in a state of being hidden (not visible), but the lower side aggregate 9D is exposed downward.

[0016] Next, the irradiation of the laser beam will be described. As the laser irradiation means for carrying out the present invention, those adopting commonly known laser light emission technologies and irradiation technologies such as diode lasers, fiber lasers, solid-state lasers, etc. are conventionally known. For example, a laser beam using a high-density wavelength beam combining (DWBC) laser source or the like can be appropriately adopted. Also, for the technology of wobbling and moving the irradiation position of the laser beam, those already known can be adopted. Furthermore, regarding the movement locus of the wobbling, there are various shapes such as circular arc movement, zigzag movement, figure-eight movement, ∞-shaped movement, etc., and it goes without saying that these can be appropriately adopted as necessary. And as the site where the laser beam irradiation accompanied by such wobbling movement is performed, as described above, not only the butting portion X of the front and back plates 7 and 8, but also the laminated portion between the front and back plates 7 and 8, and the laminated portion between the front and back plates 7 and 8 and the aggregate 9 can be used.

[0017] In this case, when the site connected by welding (fusion) by laser beam irradiation is linear (connection line) like the butting portion X described above, the irradiation position of the laser beam is made to perform a two-dimensional wobbling movement that moves the connection line while moving in a direction crossing the connection line. On the other hand, when the welding site is a point-like site like the laminated portion, welding with two-dimensional wobbling movement can be achieved by irradiating the laser beam in a spiral shape or a vertical and horizontal grid shape, for example, centering on the position to be welded. However, when it is desired to weld the butting portion X pointwise, welding can be performed by performing a wobbling movement centering on the welding position. Also, when it is desired to weld the laminated portion along the connection line, welding can be performed by a wobbling movement accompanied by the movement of the connection line. Needless to say, regarding what kind of wobbling movement to perform, an appropriate one can be adopted based on the welding specifications. Incidentally, in FIGS. 5 and 6, the depth of welding is schematically shown in a state indicated by a triangle.

[0018] The front and back plates 7 and 8 are made of steel, which is a material to be welded by laser beam irradiation as described above. However, since it is laser beam irradiation by wobbling movement, the connecting part is linear (linear), and when the laser beam moves in the width direction crossing the connecting line and moves in the two-dimensional direction along (follows, tracks) the connecting line, the laser beam will be irradiated in a state where it passes through the same position or a plurality of nearby positions multiple times. As a result, when the plate thickness of the front and back plates 7 and 8 is too thin, there is a risk that the butting part X where the front and back plates 7 and 8 are to be welded will melt and be missing (defective). Therefore, the plate thickness of the front and back plates 7 and 8 is preferably 1.0 mm or more. Also, when the plate thickness is too thick, there is a risk that the welded part of the front and back plates 7 and 8 will be biased only to the surface part side irradiated with the laser beam, resulting in a problem of insufficient welding. Therefore, the plate thickness of the front and back plates 7 and 8 is preferably 2.2 mm or less. However, it is judged that such a situation can be resolved depending on irradiation conditions such as irradiation energy and irradiation time. - And welding was attempted by irradiating the butting part X of the front and back surface materials 7 and 8 with such a plate thickness with a laser beam accompanied by an arc-shaped wobbling movement. In the drawing, the part indicated by the symbol Z is the welded part.

[0019] Welding conditions · Laser beam generator: MOTOMAN-MC2000 (manufactured by Yaskawa Electric Corporation) · Laser oscillator: TruDisk6001 · Laser beam output: 2 kW · Wobbling width and shape: Arc shape with a diameter of 2 mm · Moving speed in the connecting line direction: 2 m / min · Plate thickness of the front and back surface materials: 1.6 mm · Plate thickness of the middle frame: 2.3 mm

[0020] A laser beam irradiation experiment was conducted on the abutting portion X of the front and back plates 7 and 8 under the above conditions. First, regarding the case where there is a gap in the abutting portion X, when checking the state during welding, it was found that when the gap was up to 0.5 mm, welding was performed with all the gaps filled. For those with a gap of 0.6 mm to 0.9 mm, welding was performed in a state where both filled and unfilled gaps coexisted. For those with a gap of 1.0 mm or more, the gap remained unfilled. When viewed from a practical perspective, if the gap is 0.7 mm or less, there is no practical problem, and it can be preferably said that it is preferably 0.5 mm or less.

[0021] Next, the cases of laser beam irradiation under the above conditions were checked and shown in the substitute drawings of FIGS. 8 to 10. These are samples welded under the above conditions and do not have the upper bending piece portions 7e and 8e. Welding of the abutting portion X (connection line R) was performed in a state like the substitute drawing shown in FIG. 8. According to this, it was confirmed that the abutting portion X was welded in a state where the welding width was uniform and there was no protrusion of burrs. And the one in the substitute drawing of FIG. 8 was the result of attempting laser beam irradiation from a position where there was a 3 mm gap Y from the upper end edges of the bending piece portions 7b and 8b at the left and right edge portions (corresponding to the edges of the front and back plates orthogonal to the connection line of the present invention) as shown in FIG. 3(A). The one in the substitute drawing shown in FIG. 9 is a view of the same part with the shooting direction changed. According to these, the welded part did not reach the upper end edge which is the cut end, and the upper end edge remained in its original state without being deformed or missing. This is not only preferable in appearance but also eliminates the need for operations such as repair with putty. On the other hand, the one in the substitute drawing of FIG. 10 is welded starting from the upper end edge of the abutting portion X in the bending piece portions 7b and 8b at the left and right edge portions. According to this substitute drawing above, it was confirmed that the upper end edge which is the starting point of welding was deformed (melted) by welding to form a state where the opening was formed and there was a missing part.

[0022] It was confirmed that the presence or absence of such edge deformation and loss is the same not only at the start but also at the end of irradiation. Therefore, when the gap Y from the edge to the start and end of laser beam irradiation was examined, when the laser beam irradiation was performed with a gap Y of approximately 2 mm from the edge, no edge deformation or loss was observed, which was suitable. However, when the gap was smaller than this, edge deformation and loss were sporadically observed. However, if edge deformation and loss are not a problem, laser beam irradiation can be performed from the edge. When considering increasing this gap Y, when it exceeded 7 mm, the non-welded part from the edge became longer, resulting in a state lacking stability in appearance, which was not preferable. However, if this is not a problem, there is no problem even if it exceeds 7 mm. This is also the same for the corner where the connecting line is bent at a right angle, that is, the corner L of the front and back plates 7 and 8 perpendicular to the connecting line R as shown in Fig. 11(A). When welding reaches the corner L, deformation or loss of the corner is observed. To avoid this, it is preferable to perform laser beam irradiation with a gap Y of 2 mm to 7 mm from the corner L for the corner L as well.

[0023] Furthermore, when laser beam irradiation was performed under the above conditions, the wobbling was in the shape of an arc with a diameter of 2 mm, and this arc diameter was 125% of the plate thickness of the front and back plates 7 and 8. In this case, the welding of the abutting part X was the welding up to the front and back plates 7 and 8 that did not reach the aggregate 9, but almost the entire back surface of the front and back plates 7 and 8 was in a welded state (the state shown by the triangle in Fig. 5(A)). Therefore, since the aggregate 9 is not welded, there is no deformation or the like (influence) due to welding, and the intended strength and shape of the aggregate 9 can be maintained. Fig. 8 shows the welded state under the above conditions as a drawing substitute photograph. Incidentally, in the case of the substitute photograph of FIG. 8, just incorporating the front and back plates 7 and 8 and the aggregate 9 does not fix (temporarily fix) them and they become unstable. Therefore, a pre-integrated one by conventional spot plug welding is used. However, the welding of the front and back plates 7 and 8 and the aggregate 9 can also be carried out as the welding by the wobbling movement of the present invention.

[0024] In this case, when welding the abutting portion X, there may be a case where a spot-like portion is welded up to the aggregate 9 to be integrated, and the other portions are welded only at the abutting portion X. In such a case, for the portion to be welded up to the aggregate 9, for example, the irradiation output of the laser beam is increased, the irradiation time is lengthened (the moving speed is decreased), the wobbling movement locus is made dense, etc., so that the welding reaches the aggregate 9 partially (the state shown by the triangle in FIG. 5(B)). By doing so, in the process of welding the abutting portion X between the front and back plates 7 and 8 as a connecting line, welding that reaches the aggregate 9 partially is performed. As a result, it is not necessary to perform the welding operation for integrating the front and back plates 7 and 8 and the aggregate 9 as a separate operation from the welding operation of the abutting portion X, and the workability is improved. Of course, when performing such work, a maintenance device for maintaining the front and back plates 7 and 8 and the aggregate 9 in the incorporated state shape is required. For example, a device that presses and maintains the portion that abuts on the aggregate leg piece portion 9a of the front and back plates 7 and 8 so as not to interfere with the laser beam irradiation of the abutting portion X can be presented.

[0025] Also, regarding the moving width in the direction crossing the butting portion X of the laser beam during the wobbling movement, it is set to 2 mm (125% with respect to the plate thickness of the front and back plates 7 and 8) under the above conditions. However, when examining this moving width, a range of 0.8 mm (50%) to 3.2 mm (200%) is suitable. If it is smaller than 0.8 mm, when there is a gap in the butting portion X, it is sometimes found that the welding to close this gap is not sufficient. Also, if it exceeds 3.2 mm, there is a problem that the welding width only becomes unnecessarily wide and the workability deteriorates.

[0026] Furthermore, when considering the thickness of the front and back plates 7 and 8, laser beam irradiation accompanied by wobbling movement has a high irradiation energy. Therefore, if the thickness of the front and back plates 7 and 8 is as thin as 0.6 mm, the steel material will melt and fall off from the parts where the front and back plates 7 and 8 are not irradiated by the laser beam, and the shape cannot be maintained. The thickness of the front and back plates 7 and 8 that can avoid such a situation is 1.2 mm or more. If it is too thick, surface welding will occur. To avoid this, it is preferably 2.0 mm or less. In particular, when it is 1.6 mm, it is also suitable in terms of appearance, and a steel door with the required specifications can be efficiently manufactured. However, as the main factors for such problems, it can be mentioned that the irradiation energy of the laser beam is either too large or too small. Therefore, by appropriately adjusting the irradiation output of the laser beam, the speed of the wobbling movement, and the trajectory of the wobbling movement, welding can be performed without problems for both thick and thin materials.

[0027] In the present embodiment configured as described above, when manufacturing the door body 1 by welding the butting part X between the front and back plates 7 and 8 by laser beam irradiation, the laser beam irradiation on the butting part X involves wobbling movement that moves the irradiation position in the two-dimensional direction. Specifically, the butting part X between the bent pieces 7b and 8b of the front and back plates 7 and 8 is used as the connecting line, and it is by the two-dimensional wobbling movement that moves the connecting line while moving in the direction crossing the connecting line. Therefore, even if the front and back plates 7 and 8 have a certain thickness or there is a gap in the butting part X, and it cannot be welded by the conventional simple linear laser beam irradiation, reliable welding can be achieved with almost no problems such as thermal distortion, and a steel door can be efficiently manufactured. And in this case, since the butting part X is arranged with the overlapping part 9b of the frame member 9 lined on the back side, the butting part X will be welded by laser beam irradiation in a state reinforced by the overlapping part 9b, and it is possible to avoid the melted steel material from falling off inadvertently.

[0028] Moreover, in this case, when the welding by laser beam irradiation at the abutting portion X is carried out in a state where the welding does not reach through the bent piece portions 7b and 8b, that is, does not reach the aggregate 9, the front and rear plate members 7 and 8 can be welded to each other, and the aggregate 9 can be made unaffected by the welding, enabling highly accurate welding. - On the other hand, when the welding by laser beam irradiation reaches up to the aggregate 9, the welding at the abutting portion X site can be simultaneously performed as the welding between the abutting portions X and the welding to the aggregate 9 at this site, improving the workability. Moreover, although the embodiment described above is implemented with the bent piece portions 7e and 8e provided at the upper edge portions of the front and rear plate members 7 and 8, it can also be implemented without the bent piece portions 7e and 8e. Further, as a welding mode for the bent piece portions 7e and 8e provided at the upper edge portion of the door body 1, the bent piece portions 7b and 8b provided at the left and right edge portions, and the corner portions (angular portions) L between these vertical and horizontal bent piece portions 7b, 7e and 8b, 8e, as shown in FIG. 11(B), the welding shown in FIG. 11(A) can be made by welding the corner portion L at an intermediate portion separated from the triangular corner top T. Furthermore, as shown in FIG. 11(C), for the case where the corner portion L is welded in a state reaching up to the triangular corner top T, the welding shown in (A) can also be performed. - Moreover, although the embodiment described above is implemented with the bent piece portions 7e and 8e provided at the upper edge portions of the front and rear plate members 7 and 8, it can also be implemented without the bent piece portions 7e and 8e. Further, as a welding mode for the bent piece portions 7e and 8e provided at the upper edge portion of the door body 1, the bent piece portions 7b and 8b provided at the left and right edge portions, and the corner portions (angular portions) L between these vertical and horizontal bent piece portions 7b, 7e and 8b, 8e, as shown in FIG. 11(B), the welding shown in FIG. 11(A) can be made by welding the corner portion L at an intermediate portion separated from the triangular corner top T. Furthermore, as shown in FIG. 11(C), for the case where the corner portion L is welded in a state reaching up to the triangular corner top T, the welding shown in (A) can also be performed.

[0029] Moreover, although the embodiment described above is implemented with the bent piece portions 7e and 8e provided at the upper edge portions of the front and rear plate members 7 and 8, it can also be implemented without the bent piece portions 7e and 8e. Further, as a welding mode for the bent piece portions 7e and 8e provided at the upper edge portion of the door body 1, the bent piece portions 7b and 8b provided at the left and right edge portions, and the corner portions (angular portions) L between these vertical and horizontal bent piece portions 7b, 7e and 8b, 8e, as shown in FIG. 11(B), the welding shown in FIG. 11(A) can be made by welding the corner portion L at an intermediate portion separated from the triangular corner top T. Furthermore, as shown in FIG. 11(C), for the case where the corner portion L is welded in a state reaching up to the triangular corner top T, the welding shown in (A) can also be performed. As the form of the welding, reference examples of welding are shown in FIGS. 11(D) and (E). As shown in FIG. (D) of the same drawing, for the corner portion L welded at an intermediate portion spaced from the triangular corner top T, the welding portions between the bent pieces 7b, 8b and 7e, 8e are connected to the welding at the triangular corner portion. As shown in FIG. (E) of the same drawing, for the corner portion L welded in a state reaching the triangular corner top T, the welding portions between the bent pieces 7b, 8b and 7e, 8e are connected to the welding at the triangular corner portion. In these cases, since there is a mating member that receives the melted material by the irradiation of the laser beam for the welding of each corner portion, the edge portion does not melt and deform (fall off) as in the case of welding the cut end shown in FIG. 10 described above, and welding can be performed in an excellent appearance state.

Industrial Applicability

[0030] The present invention can be used as a steel door using front and rear plates with a thick plate thickness. Manufacturing method It can be used as such.

Explanation of Signs

[0031] 1 Door body 7 Front plate 7a Front surface portion 7b Bent piece portion 7c Edge portion 8 Rear plate 8a Rear surface portion 8b Bent piece portion 8c Edge portion 9 Frame member 9a Leg piece portion 9b Straddle piece portion X Abutted portion Y Gap Z Welding portion

Claims

1. In a method for manufacturing a steel door, the method includes an irradiation process in which a joint portion between the front and back panels of a door body having a steel plate as a front and back panel is welded by irradiation with a laser beam, the joint portion between the front and back panels being a linear joint line, and the irradiation in the irradiation process of the laser beam includes irradiation by a two-dimensional wobbling movement that moves across the joint line while moving in the width direction, The connecting line is provided so that the start end or end end reaches an edge of the front and back plates perpendicular to the connecting line; A manufacturing method for a steel door, characterized in that the welding in the irradiation step is performed with a gap from the start or end of the connection line.

2. In a method for manufacturing a steel door, the method includes an irradiation process in which a joint portion between the front and back panels of a door body having a steel plate as a front and back panel is welded by irradiation with a laser beam, the joint portion between the front and back panels being a linear joint line, and the irradiation in the irradiation process of the laser beam includes irradiation by a two-dimensional wobbling movement that moves across the joint line while moving in the width direction, The connecting line is provided so that the start end or end thereof reaches a corner of the front and back plates perpendicular to the connecting line; A manufacturing method for a steel door, characterized in that the welding in the irradiation step is performed with a gap from the start or end of the connection line.

3. 3. The method for manufacturing a steel door according to claim 1, wherein the gap between the start or end of the connection line and the laser beam irradiation is 3 to 7 mm.

4. A method for manufacturing a steel door as described in any one of claims 1 to 3, characterized in that the connection portion between the front and back panels is an abutment portion where the end edges of folded pieces which are bent from the front and back surfaces of the front and back panels to face each other and form the end edge portion of the door body are abutted against each other, and the abutment portion is abutted by a side piece of the folded piece of a frame which has a pair of front and back surface side pieces abutting against the front and back surfaces, and the portion which is irradiated by the wobbling movement of the laser beam is the abutment portion where the side pieces of the folded piece abut.

5. 5. The method for manufacturing a steel door according to claim 4, wherein the welding of the butting portions by irradiation of a laser beam is performed in a state where the welding does not penetrate through the folded piece and the side piece.

6. 6. The method for manufacturing a steel door according to claim 4 or 5, wherein the welding of the butting portions by irradiation of a laser beam is performed up to the folded pieces but not to the side pieces of the folded pieces.

7. A method for manufacturing a steel door according to any one of claims 4 to 6, characterized in that the width of movement across the connection line of the laser beam irradiation between the abutting portions is in the range of 50% to 200% of the plate thickness of the front and back panels.

8. The method for manufacturing a steel door according to any one of claims 1 to 7, characterized in that the thickness of the front and back panels is 1.2 mm to 2.0 mm.

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