JP2013212522A - Method and device for indirect spot welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform spot welding of a bag structure part, etc., in high quality with a simple device.SOLUTION: An indirect spot welding method for welding first and second plate materials includes a first step in which the first and second plate materials are so arranged as to overlap with each other in a welding object part by using a welding gun provided with a pressurizing electrode and power-supplying electrode and further a bending tool, and further by using a second plate material provided with a standing-state to-be-welded piece; a second step in which the to-be-welded piece is so bent as to overlap with the first plate material in the welding object part by the bending tool by moving the welding gun along the first plate material; and a third step in which the pressurizing electrode is brought into contact with the to-be-welded piece bent in the second step, and the power-supplying electrode is brought into contact with a part distant from the welding object part in the first plate material to energize for welding.

Description

  The present invention relates to an indirect spot welding method used for welding a bag structure portion or the like in a frame plate constituting a vehicle body of an automobile, and a welding apparatus for the same.

  Conventionally, direct spot welding, in which current is directly applied in the plate thickness direction, is widely used for welding between members, but the direct spot welding is performed on both sides of the overlapped base metal (upper electrode). The lower electrode) is placed and sandwiched, so that the welding current is pressed and applied in the thickness direction directly from the electrodes in contact with both sides. Therefore, it is desirable to leave spot welding marks on the surface of the base metal plate on one side. Indirect spot welding is performed when spot welding is performed on a non-existing portion or when it is difficult to arrange an electrode on the back surface side.

  Indirect spot welding is an area where spot welding is performed (electrode for pressurization) and an electrode (power supply electrode) at a position different from that of the electrode in plan view, except for the welded portion of one base material. This is spot welding in which current is passed through the part. For example, Patent Document 1 describes a conventional invention for performing indirect spot welding. According to the conventional technique described in Patent Document 1, a welding electrode 26 that contacts the hemming bent portion 4a, and the welding electrode 26 are described. The hemming bent portion 4a can be spot-welded by supplying current through the door inner panel 5 which is a base material between the feeding electrode 30 on the same side as that of the feeding electrode 30 at a different position in plan view. . In addition, the said patent document 1 also describes that the bending process of the hemming bending part 4a can be performed with the same welding apparatus.

JP-A 64-057986

  However, the technique described in Patent Document 1 still has room for improvement as described below.

  That is, for example, when spot-welding a bag structure in a frame plate material that constitutes the body of an automobile, the mother is placed on the opposite side of the pressure electrode during welding, that is, on the position facing the pressure electrode from the inside of the bag structure. A cradle or the like that supports the material could not be provided, and a sufficient pressure contact force between the base materials could not be obtained during welding, so stable quality welding could not be performed. In particular, if the thickness of the upper plate constituting the outside of the bag structure is thick, the pressure contact force with the lower plate may be insufficient even if the pressing electrode is pressed against the upper plate with normal pressure during welding. there were. In addition, even when there are variations in the gap between the base materials to be welded, if the gap between the base materials is large, the pressure contact force between the upper and lower plates may be insufficient, so stable quality welding could not be performed. Furthermore, because of the bag structure, the welded state of the welded portion cannot be visually confirmed, and it is difficult to inspect the welding strength by a semi-destructive inspection or the like.

  The present invention provides stable quality welding even when spot welding is performed on a structure such as a bag structure where the pressure between the base materials cannot be sufficiently obtained during welding and the welding state cannot be visually confirmed. The main purpose is to realize a simple configuration.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a part separated from the welding target part by bringing the pressure side electrode into contact with one member in the welding target part where the first and second plate members are overlapped. In the indirect spot welding method of welding the first and second plate members at the welding target site by bringing a power supply side electrode into contact with the other member and energizing between these electrodes, the pressurizing electrode and A welding gun provided with a bending tool is used as the welding gun provided with the power supply electrode, and the first and second plate members are welded to each other using a standing plate as the second plate member. A first step of placing the welding guns so as to overlap each other at the target site, and moving the welding gun along the first plate member, so that the welding piece is moved at the welding target site by the bending tool. A second step of bending so as to overlap the plate material, and the pressing electrode on the welded piece bent in the second step, and the power supply electrode on a portion of the first plate material spaced from the welding target portion. And a third step of welding by energizing each in contact with each other.

  The invention according to claim 2 is the invention according to claim 1, wherein, in the second step, the bending tool having a guide groove is used, and the welding piece is bent while being guided by the guide groove. Features.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the bending tool is provided integrally with the power supply electrode.

  According to a fourth aspect of the present invention, a pressure side electrode is brought into contact with one member at a welding target portion where the first and second plate members are overlapped, and a power feeding side electrode is connected to the other member at a portion separated from the welding target portion. Is an indirect spot welding method in which the first and second plate members are welded at the welding target site by energizing between these electrodes, and the welding includes the pressurizing electrode and the power feeding electrode. The gun is provided with a bending tool, the first plate member is provided with a long hole, and the second plate member is provided with a standing piece to be welded, and the second plate member is welded. A first step of arranging the first and second plate members so as to overlap each other in the welding target portion while passing a piece through the elongated hole of the first plate member, and the welding gun along the first plate member Moved Thus, the second step of bending the welded piece with the bending tool so as to overlap the first plate at the site to be welded, and the added to the welded piece bent in the second step. And a third step of welding the pressure electrode by bringing the power feeding electrode into contact with a portion of the first plate member spaced apart from the portion to be welded and applying current thereto.

  The invention according to claim 5 is the invention according to claim 4, wherein the bending tool is provided integrally with the power feeding electrode.

  The invention according to Claim 6 is the invention according to any one of Claims 1 to 5, wherein the second plate material is a plate material thinner than the first plate material.

  The invention according to claim 7 is the invention according to any one of claims 4 to 6, wherein the first plate member is a frame plate member of a vehicle body, and the second plate member is a reinforcing member disposed on the frame plate member. It is characterized by that.

  According to an eighth aspect of the present invention, a pressure side electrode is brought into contact with one member at a welding target portion where the first and second plate members are overlapped, and a power feeding side electrode is placed on the other member at a portion separated from the welding target portion. In an indirect spot welding apparatus that welds the first and second plate members at the welding target site by energizing between these electrodes, a bending tool is provided together with the pressing electrode and the feeding electrode. The welding gun is moved along the first plate member with respect to the second plate member provided with the first plate member and the upright welded piece arranged so as to overlap with the welding gun part. By bending the welded piece with the bending tool so as to overlap the first plate at the site to be welded, the pressurizing electrode is placed in front of the folded welded piece. Characterized by comprising a control means for controlling to weld by energizing respectively brought into contact with the power supply electrode at a site remote from the welded portion in the first plate member.

  The invention according to claim 9 is the invention according to claim 8, wherein the bending tool includes a guide groove for guiding the welded piece when bent.

  The invention according to claim 10 is the invention according to claim 8, wherein the bending tool is provided integrally with the power feeding electrode.

  According to the first aspect of the present invention, since the welding piece can be bent into the first plate by the bending tool provided in the welding gun by moving the welding gun, the spot of the bag structure portion or the like can be easily bent. Welding can be achieved with high quality, and since the welded piece that is the welded part is outside the bag structure, the welding state can be visually confirmed.

  According to the second aspect of the present invention, it is possible to achieve appropriate bending of the welded piece by the guide groove.

  According to the invention which concerns on Claim 3, bending of a to-be-welded piece can be achieved with an electric power feeding side electrode, and spot welding can be achieved with a simple structure.

  According to the invention of claim 4, the same effect as that of the invention of claim 1 can be obtained.

  According to the invention of claim 5, the same effect as that of the invention of claim 3 can be obtained.

  According to the invention which concerns on Claim 6, it is easy to bend the to-be-welded piece, and even if it is between board | plate materials with which the clearance between board is not constant (when an upper board is a thick board and a lower board is a thin board), the welding object site | part is in specification The minimum gap between the plates can be made constant, and stable welding quality can be obtained.

  According to the invention which concerns on Claim 7, the member which heightened the reinforcement effect with the reinforcement board | plate material in the frame board | plate material of a vehicle body can be manufactured in a simple process.

  According to the inventions according to claims 8 to 10, the same effects as those of the inventions according to claims 1 to 3 can be obtained, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic showing the whole structure and welding object site | part of the welding apparatus of 1st Embodiment by this invention. It is an enlarged view of the welding object site | part welded by 1st Embodiment, (a) shows the state before bending a to-be-welded piece, (b) shows the state after bending to-be-welded piece, respectively. It is a three-view figure of the bending tool of 1st Embodiment. It is a schematic diagram showing the 1st process in the welding method of a 1st embodiment. It is a schematic diagram showing the 2nd process in the welding method of a 1st embodiment. It is a schematic diagram showing the 3rd process in the welding method of a 1st embodiment. It is a schematic diagram showing the 4th process in the welding method of a 1st embodiment. It is the front view and top view of the bending tool of 2nd Embodiment. It is a schematic diagram showing the 1st process in the welding method of a 2nd embodiment. It is a schematic diagram showing the 2nd process in the welding method of a 2nd embodiment. It is a schematic diagram showing the 3rd process in the welding method of a 2nd embodiment. It is a schematic diagram showing the 4th process in the welding method of a 2nd embodiment. It is an enlarged view of the welding object site | part welded by 3rd Embodiment, (a) shows the state before bending a to-be-welded piece, (b) shows the state after bending to-be-welded piece, respectively. It is a three-view figure of the bending tool of 3rd Embodiment. It is a front view of the bending tool of 4th Embodiment. It is a front view of the bending tool of 5th Embodiment. It is a perspective view of the principal part of the vehicle body of the motor vehicle which applies the welding method of this invention. (A) is a perspective view which shows the state before bending the to-be-welded piece of the gusset which comprises the vehicle body of FIG. 17, (b) is a perspective view which shows the modification. It is a cross-sectional enlarged view which shows the welding site | part of the vehicle body of FIG. FIG. 18 is an enlarged view showing a modified example of the shape around the long hole opened in the second plate member of FIG. 17.

Hereinafter, modes for carrying out the present invention will be described based on first to fifth embodiments. In the description of each embodiment, terms that indicate directions (for example, “upward”, “downward”, “right side”, “left side”, etc.) are used as appropriate for easy understanding. However, these terms do not limit the present invention. In the accompanying drawings, the same components are referred to by the same reference numerals.
[First Embodiment]

  The first embodiment of the present invention will be described in detail below with reference to FIGS. First, the overall configuration of the first embodiment will be described with reference to FIG.

  The indirect spot welding apparatus 10 of the first embodiment is mainly composed of a welding gun 1 and a robot arm 2 that attaches the welding gun 1 to the tip, and moves the robot arm 2 with the necessary degree of freedom. By controlling, it is possible to perform welding by appropriately controlling the position, direction, and posture of the welding gun 1 with respect to the site to be welded.

  The welding gun 1 includes a welding transformer 3 and a gun mounting bracket 4, and a pair of air and servo stud guns 5 are mounted on the gun mounting bracket 4. A pressure electrode 7 and a power supply electrode 8 are respectively attached to the air and servo stud gun 5 via electrode attachment point holders 6.

  Here, as a feature of the present invention, a folding flat plate 11 is attached to the gun mounting bracket 4 via a bending plate mounting slide base plate 9 as a bending tool. The pressure electrode 7, the power supply electrode 8, and the bending flat plate 11 are integrally provided.

  The flat plate 11 for bending is provided with a guide groove portion 11a that comes into contact with a member to be welded (welded piece 101a) at the tip thereof. Further, the folding flat plate 11 is provided with slide rails 11d on both side surfaces thereof so as to be slidable in the longitudinal direction with respect to the bending plate mounting slide base plate 9 when contacting the member to be welded. The slide rail 11 is slidably engaged with a slide groove 9a (not shown) provided in the bending plate mounting slide base plate 9. Further, in order to stably bring the folding flat plate 11 into contact with the member to be welded, a bolt 11e is provided at the base end of the bending flat plate 11 and is provided on the plate mounting slide base plate 9. The tip of the bolt 11e is inserted into the through-hole 9b, and a pressing assisting spring 9c is provided on the outer periphery of the bolt 11e between the bending flat plate 11 and the bending plate mounting slide base plate 9. When the bending flat plate 11 slides with respect to the plate mounting slide base plate 9, the pressing assisting spring 9 c applies a biasing force to the bending flat plate 11.

  Next, the member to be welded according to the first embodiment will be described with reference to FIG.

  Regarding the plate thickness of the two plate materials (the first plate material 101 and the second plate material 102) that are welded to each other, the second plate material 102 is thicker than the first plate material 101. In order to weld between these plate materials, the second plate material 102 is disposed on the upper side of the first plate material 101, and these plate materials are overlapped. At this time, a welded piece 101a is cut and raised in advance in the first plate 101 at a position adjacent to the site to be welded, and a long hole 102a is formed in the second plate 102 so as to pass therethrough. Positioning is performed such that the weld piece 101 a passes through the elongated hole 102 a, and the second plate material 102 is overlaid on the first plate material 101. As a result, the welded piece 101a protrudes from the upper surface of the second plate member 102 (see FIG. 2A). This is the preparation stage for spot welding.

  Next, the welded piece 101a protruding from the upper surface of the first plate member 102 is bent by the bending flat plate 11 which is a bending tool, and the peripheral portion of the welded piece 101a and the long hole 102a of the second plate member 102 are Are superimposed (see FIG. 2B). Since the overlapped portion becomes a welding target portion, the welded piece 101a is parallel to the second plate 102 so that the welded piece 101a is in surface contact with the peripheral edge of the elongated hole 102a of the second plate 102. Bend it.

  Subsequently, the pressing electrode 7 is brought into contact with the bent upper surface of the welded piece 101a, and the second plate member 102 is separated from the welded piece 101a in a plan view from the same side as the pressing electrode 7. The first plate member 101 and the second plate member 102 are spot-welded by bringing the power supply electrode 8 into contact and energizing between these electrodes.

  In addition, the shape of the to-be-welded piece 101a and the long hole 102a is not restricted to what was shown by FIG. It suffices that the welded piece 101a can be inserted through the elongated hole 102a and the lower side of the bent welded piece 101a can be opposed to the periphery of the elongated hole 102a with a contact area sufficient for spot welding.

  Further, the relationship between the plate thicknesses of the two plate members to be welded to each other is not limited to the case where the second plate member 102 is thicker than the first plate member 101, and these plate pressures may be the same thickness. On the contrary, even when the second plate member 102 is thinner than the first plate member 101, the present invention may be applicable by increasing the pressing force than usual.

  Furthermore, although the case where the long hole 102a is provided in the 2nd board | plate material 102 has been described, it does not restrict to this. For example, when spot welding the first plate material 101 to the edge of the second plate material 102, the second plate material 102 is not provided with a long hole, and the welded piece 101 a of the first plate material 101 is attached to the second plate material 102. Spot welding can be performed by the same welding apparatus or method as described above by bending the edge portion so as to be sandwiched from the outside.

  Moreover, although the case where the to-be-welded piece 101a was provided in the 1st board | plate material 101 by cutting and raising was described, it does not restrict to this. For example, when spot welding the second plate material 102 to the edge of the first plate material 101, the first plate material 101 is not cut and raised to provide the welded piece 101a, but the edge of the first plate material 101 has a convex shape. The protruding piece is provided as a welded piece 101a, and the welded piece 101a is inserted into the elongated hole 102a of the second plate 102 and bent, so that the spot can be spotted by the same welding apparatus or method as described above. Welding is possible.

  Next, the bending tool of the first embodiment will be described with reference to FIG.

  The flat plate 11 for bending is a bending tool that bends the welded piece 101a in a predetermined direction at a predetermined position, and stands upright at the tip of the bending flat plate 11 that abuts the welded piece 101a during bending. A guide groove portion 11a for guiding and positioning the welded piece 101a in the inward state is provided, and the width of the guide groove portion 11a is slightly larger than the width of the welded piece 101a. And the corner | angular part which makes the boundary of the bottom face of the guide groove part 11a and the lower end surface of the bending flat plate 11, and the surface in which the inner side surface of the guide groove part 11a and the guide groove part 11a of the bending flat plate 11 were provided are provided. A bottom chamfered portion 11b and a side chamfered portion 11c are respectively provided at the corners forming the boundary. By providing the bottom surface chamfered portion 11b, the bottom surface chamfered portion 11b and the to-be-welded piece 101a are first brought into contact with each other at the time of bending, so that the to-be-welded piece 101a can be gradually bent without applying excessive force. Further, by providing the side chamfered portion 11c, it is possible to guide to the guide groove portion 11a even when the standing piece 101a to be welded is slightly tilted.

  Further, as described above, the bending flat plate 11 is slidable in the longitudinal direction with respect to the bending plate mounting slide base plate 9 when contacting the member to be welded. 11d is provided. The slide rail 11 is slidably engaged with a slide groove 9a provided on the bending plate mounting slide base plate 9.

  Furthermore, although it repeats, in order to make the flat plate 11 for bending contact | abut stably with respect to a to-be-welded member, the volt | bolt 11e is provided in the base end part of the flat plate 11 for bending. The tip of the bolt 11e is inserted into a through hole 9b provided in the plate mounting slide base plate 9, and is held on the outer periphery of the bolt 11e between the bending flat plate 11 and the bending plate mounting slide base plate 9. Thus, when the bending flat plate 11 slides with respect to the bending plate mounting slide base plate 9, an urging force can be applied to the bending flat plate 11.

  Next, each step in the welding method of the first embodiment will be described in detail with reference to FIGS. 4 to 7.

  In addition, for the first plate member 101 and the second plate member 102 that are spot-welded to each other, the first plate member 101 is provided by cutting and raising the workpiece 101a in advance, and the second plate member 102 is provided with a long hole 102a that passes therethrough. deep. And it aligns so that the to-be-welded piece 101a may penetrate the elongate hole 102a, and the 2nd board | plate material 102 is piled up on the 1st board | plate material 101. FIG.

  When the welding preparation steps so far are completed, the first step is to move the welding gun 1 on which the feeding electrode 8, the pressing electrode 7, and the bending flat plate 11 are mounted, from the original position to the second step. The bending flat plate 11 is brought close to a height position at a distance corresponding to the thickness of the workpiece 101a from the plate material 102 (see FIG. 4).

  For convenience of explanation, the drawing is a schematic diagram in a weldability experiment, and the first plate member 101 and the second plate member 102 are drawn in a flat plate shape, but the shape of these plate members is not limited to this. Further, the first plate material 101 is placed on the support base 103 (for positioning the plate material in the embodiment), and the second member 102 is placed thereon. However, the setting method of the member to be welded at the time of welding is limited to this. is not.

  As a second step, the welding gun 1 is moved along the first plate member 101, so that the welding target piece 101 a is guided by the guide groove 11 a by the bending flat plate 11 mounted on the welding gun 1. Bending is performed so as to overlap the plate material 102 (see FIG. 5).

  As a third step, the welding gun 1 is moved obliquely upward, and the pressurizing electrode 7 is moved immediately above the spot welding spot position (see FIG. 6).

  As a fourth step, upon receiving a gun pressurizing command, the air and servo stud gun 5 are driven to lower the pressurizing electrode 7 and the power feeding electrode 8, and the pressurizing electrode 7 is bent to the welded piece 101 a. Then, spot welding is performed by energizing between the electrodes while the power supply electrode 8 is in contact with a portion of the first plate 101 that is a portion to be welded that is a portion to be welded 101a (see FIG. 7). ).

  As a fifth step, after the end of welding, the servo gun 1 is raised, the electrodes 7 and 8 are separated from the members to be welded 101 and 102, and the welding gun 1 is moved to the original position (not shown).

  In addition, when welding a some to-be-welded site | part continuously, it is good to determine an original position in consideration of the position of the to-be-welded site | part performed continuously before and behind in order to improve work efficiency.

  The spot welding between the plates of the first plate 101 and the second plate 102 is completed through the above steps.

  Since the pressurizing electrode 7, the power feeding electrode 8, and the bending flat plate 11 are separately attached to the gun mounting bracket 4 of the welding gun 1, any of these components can be replaced due to damage or the like. If necessary, it is sufficient to replace only that part.

As described above, according to the first embodiment, the welded piece can be bent by the bending tool provided in the welding gun by the movement of the welding gun. Therefore, high-quality spot welding of the bag structure portion or the like can be performed by easy bending. Can be achieved. Moreover, since the to-be-welded piece used as a welding part has come out of the bag structure part, a welding state can be confirmed visually and it is also possible to test | inspect welding strength by a semidestructive inspection etc. Further, even when the upper plate (second plate member) is thicker than the lower plate (first plate member), the upper plate is formed in this portion by passing the welded piece of the lower plate through the long hole of the upper plate. In addition, since the upper and lower sides of the lower plate are reversed, even when the pressing electrode is pressed with a normal pressing force during welding, the press contact force between the plate members is sufficient, and stable quality spot welding is possible. In addition, even when there are variations in the gaps between the plate materials to be welded, a sufficient pressure can be applied between the plate materials for the same reason, so that stable quality welding is possible.
[Second Embodiment]

  Next, a second embodiment according to the present invention will be described in detail below with reference to FIGS. First, the bending tool of the second embodiment will be described with reference to FIG.

  As described above, in the first embodiment, the work piece is bent by a bending tool provided separately from the electrode, whereas in the second embodiment, the bending tool is integrated with the power feeding electrode. It is different in that it is provided. In other words, in the second embodiment, bending is also performed by the power supply electrode, and the power supply electrode is also used as a bending tool.

  The outline of the power supply electrode 18 of the second embodiment is the same as that of the power supply electrode 8 of the first embodiment, but is also used to bend the welded piece 101a in a predetermined direction at a predetermined position. Therefore, the shape is partially different. That is, a guide groove portion 18a for guiding and positioning the welded piece 101a inward is provided on the side surface of the distal end portion of the power supply electrode 18 that abuts the welded piece 101a that stands up when bent. The width of the guide groove 18a is slightly larger than the width of the welded piece 101a. Then, similarly to the guide groove portion 11a provided in the bending flat plate 11 of the first embodiment, the corner portion that forms the boundary between the bottom surface of the guide groove portion 18a and the lower end surface of the power feeding electrode 18, and the guide groove portion A bottom chamfered portion 18b and a side chamfered portion 18c are provided at corners that form a boundary between the inner side surface of 18a and the cylindrical surface on which the guide groove portion 18a of the power feeding electrode 18 is provided. By providing the bottom chamfered portion 18b, the bottom chamfered portion 18b is first brought into contact with the workpiece 101a that is upright at the time of bending, so that the workpiece 101a can be bent gradually without applying an excessive force. Further, by providing the side chamfered portion 18c, it is possible to guide to the guide groove portion 18a even when the standing piece 101a to be welded is slightly tilted.

  Next, each step in the welding method of the second embodiment will be described in detail with reference to FIGS. 9 to 12.

  As in the first embodiment, the first plate material 101 and the second plate material 102 that are spot-welded to each other are provided by cutting and raising the workpiece 101a in advance in the first plate material 101 and penetrating through the second plate material 102. A long hole 102a is provided. And it aligns so that the to-be-welded piece 101a may penetrate the elongate hole 102a, and the 2nd board | plate material 102 is piled up on the 1st board | plate material 101. FIG.

  When the welding preparation steps so far are completed, as a first step, the welding gun 1 having the pressurizing electrode 7 and the feeding electrode 18 mounted at the tip thereof is moved, and the second plate member 102 is moved from the original position. The power feeding electrode 18 is brought close to a height position that is separated by a distance corresponding to the plate thickness of the weld piece 101a (see FIG. 9).

  As a second step, the welding gun 1 is moved along the first plate material 101, whereby the welded piece 101a is bent by the power supply electrode 18 so as to overlap the second plate material 102 (see FIG. 10).

  As a third step, the welding gun 1 is moved obliquely upward, and the pressurizing electrode 7 is moved immediately above the spot welding spot position (see FIG. 11).

  As a fourth step, upon receiving a gun pressurization command, the air and the servo stud gun 5 are driven to lower the pressurization electrode 7 and the power supply electrode 18 from the welding gun 1, and the pressurization electrode 7 is bent. Spot welding is performed by energizing the welding piece 101a between these electrodes in a state in which the feeding electrode 18 is in contact with a portion of the first plate material that is a portion to be welded that is a portion to be welded in the first plate member. 12).

  As a fifth step, after the end of welding, the servo gun 1 is raised, the electrodes 7 and 8 are separated from the members to be welded 101 and 102, and the welding gun 1 is moved to the original position (not shown).

  The spot welding between the plates of the first plate 101 and the second plate 102 is completed through the above steps.

In the case of the second embodiment, a dedicated part for performing the bending process is unnecessary, and therefore the effect of the present invention can be realized with a simpler configuration.
[Third Embodiment]

  Next, a third embodiment according to the present invention will be described in detail below with reference to FIGS. First, with reference to FIG. 13, a welding target portion to be welded according to the third embodiment will be described.

  Although 1st Embodiment demonstrated what bent one to-be-welded piece, 3rd Embodiment is different from 1st Embodiment by the point which bends two to-be-welded pieces.

  Similar to the first embodiment, the plate thickness of the two plate materials (the first plate material 101 and the second plate material 102) to be welded to each other is thicker in the second plate material 102 than in the first plate material 101. In order to weld between these plate materials, the second plate material 102 is disposed on the upper side of the first plate material 101, and these plate materials are overlapped.

  At this time, two pieces 201a and 201b to be welded are provided side by side in a state in which the first plate 201 is erected by cutting and raising in advance at a position adjacent to the site to be welded, and on the second plate 202. Is provided with one elongated hole 102a through which these welded pieces 201a and 201b can be inserted at the same time, and the two welded pieces 201a and 201b are aligned so as to pass through one elongated hole 202a. Then, the second plate material 202 is overlaid on the first plate material 201. As a result, the welded pieces 201a and 201b protrude from the upper surface of the second plate member 202 (see FIG. 13A). This is the preparation stage for spot welding.

  Next, the two welded pieces 201a and 201b protruding from the upper surface of the first plate member 202 are bent, and the welded pieces 201a and 201b and the peripheral portion of the long hole 202a of the second plate member 202 are overlapped (FIG. 13). (See (b)). Since the overlapped portion becomes a welding target portion, the welded pieces 201a and 201b are parallel to the second plate material 202 so that the welded piece 201a is in surface contact with the peripheral edge of the elongated hole 202a of the second plate material 202. Bend it so that

  Subsequently, the pressurization electrode 7 is brought into contact with the upper surfaces of the bent pieces 201a and 201b, and the pressurization electrode 7 is disposed on a portion of the second plate 202 separated from the welded pieces 201a and 201b in plan view. Are brought into contact with each other from the same side, and the first plate member 201 and the second plate member 202 are spot-welded by energizing between these electrodes.

  Note that the shapes of the welded pieces 201a and 201b and the elongated hole 202a are not limited to those shown in FIG. The welded pieces 201a and 201b can be inserted through the long holes 202a, and the lower side of the bent welded pieces 201a and 201b can be opposed to the periphery of the long holes 202a with a sufficient contact area for spot welding. I just need it.

  Further, the relationship between the plate thicknesses of the two plate members to be welded to each other is not limited to the case where the second plate member 202 is thicker than the first plate member 201, and these plate pressures may be the same thickness. On the contrary, even when the second plate member 202 is thinner than the first plate member 201, the present invention may be applicable by increasing the pressure and changing the welding conditions (such as energization time) than usual. is there.

  Furthermore, although the case where the long hole 202a is provided in the 2nd board | plate material 202 has been described, it does not restrict to this. For example, when spot welding the first plate member 201 to the edge of the second plate member 202, the second plate member 202 is not provided with a long hole, and the welded pieces 201a and 201b of the first plate member 201 are second plate members. Spot welding can be performed by the same welding apparatus or method as described above, by being provided so as to stand on the outside of the edge of 202 and bending the edge so as to be sandwiched from the outside.

  Further, when the two welded pieces 201a and 201b protruding from the upper surface of the second plate member 202 are folded, the two welded pieces 201a and 201b may be folded one by one or simultaneously. From the viewpoint of improving work efficiency, it is desirable to bend the two at the same time.

  Furthermore, although the case where the to-be-welded pieces 201a and 201b are cut and raised on the first plate member 201 has been described, the present invention is not limited to this. For example, when spot welding the second plate 202 to the edge of the first plate 201, the welded pieces 201a and 201b are not provided by cutting and raising the first plate 201, but at the edge of the first plate 201. Protruding protruding pieces are provided, and the raised pieces are set as welded pieces 201a and 201b, and the welded pieces 201a and 201b are inserted into the long holes 202a of the second plate member 202 and bent, thereby being the same as described above. Spot welding can be performed by a welding apparatus or method.

  When there are two pieces to be welded according to the third embodiment, the number of welded portions between the plate members is increased compared with the case where there is one piece to be welded according to the first embodiment, so that it is possible to perform stronger spot welding. is there.

  Next, a bending tool according to a third embodiment will be described with reference to FIG.

  The flat plate 21 for bending is a bending tool that simultaneously bends the welded pieces 201a and 201b in a predetermined direction at predetermined positions, and the distal end of the flat plate 21 for bending that contacts the welded pieces 201a and 201b at the time of bending. The guide portion is provided with two guide groove portions 21a for guiding and positioning the two to-be-welded pieces 201a and 201b in an inward direction, and the width of each guide groove portion 21a is set to each welded piece. The dimensions are slightly larger than the widths of 201a and 201b. Thereby, it can be bent, guiding the to-be-welded pieces 201a and 201b by the guide groove portion 21a.

  As in the first embodiment, the corners forming the boundary between the bottom surface of each guide groove 21a and the lower end surface of the bending flat plate 21, and the inner surface of each guide groove 21a and the bending flat plate. A bottom chamfered portion 21b and a side chamfered portion 21c are respectively provided at corners that form a boundary with the surface provided with the 21 guide groove portions 21a. By providing the bottom chamfered portion 21b, the bottom chamfered portion 21b and the to-be-welded pieces 201a and 201b that first stand up contact each other almost simultaneously at the time of bending. It is possible to bend it. Further, by providing the side chamfered portion 21c, it is possible to guide to the guide groove portion 21a even when at least one of the standing pieces 201a and 201b is slightly tilted.

  In addition, the bending flat plate 21 is provided with slide rails 21d on both side surface portions thereof and with bolts 21e at the base end portions thereof, as in the first embodiment.

In the case of the third embodiment, basically the same welding method as in the first embodiment can be performed, but in the welding process, two pieces to be welded 201a and 201b bent by the pressurizing electrode 7 are 1 Since welding can be performed only one by one, it is necessary to move the welding gun 1 on which the pressing electrode 7 is mounted between the two pieces to be welded 201a and 201b.
[Fourth Embodiment]

  Next, a bending tool according to a fourth embodiment of the present invention will be described in detail below with reference to FIG.

  The bending roller mold plate 31 that is a bending tool of the fourth embodiment is different from the first embodiment in the shape of the tip portion that comes into contact with the welded piece. In the case of the first embodiment, the tip has a flat plate shape, whereas in the case of the fourth embodiment, it differs in that it has a roller shape.

  A roller 31a is rotatably provided at the front end portion of the bending roller mold plate 31 of the fourth embodiment while supporting both ends in the central axis direction. One guide groove 31b is provided over the entire circumference in the central portion of the roller 31a in the rotation axis direction. Further, a chamfered portion 31c is provided over the entire circumference at the corner of the boundary between the inner surface of the guide groove 31b and the outer peripheral surface of the roller 31a provided with the guide groove 31b.

According to the fourth embodiment, when the roller 31a can freely rotate when contacting the welded piece, it can be gradually bent without applying an excessive force to the welded piece due to friction or the like. Become.
[Fifth Embodiment]

  Next, a bending tool according to a fifth embodiment of the present invention will be described in detail below with reference to FIG.

  Similarly to the fourth embodiment, the fifth embodiment is a roller-type bending tool, but the fourth embodiment is for bending one piece to be welded. The fifth embodiment is different in that the two pieces to be welded are bent at a time.

  A roller 41a is rotatably provided at the front end of the folding roller mold plate 41 of the fifth embodiment, with both ends in the central axis direction being supported. Two guide grooves 41b are provided over the entire circumference in the central portion of the roller 41a in the rotation axis direction. Further, a chamfered portion 41c is provided over the entire circumference at the corner of the boundary between the inner surface of each guide groove 41b and the outer peripheral surface of the roller 41a provided with the guide groove 41b.

  According to the fifth embodiment, the two welded pieces can be bent at the same time, and the roller 41a can freely rotate when contacting the welded piece. It becomes possible to bend gradually without applying excessive force.

  Finally, an example in which the welding method or welding apparatus of the present invention is applied will be described with reference to FIGS. First, FIG. 17 is a perspective view of a main part of a vehicle body of an automobile to which the welding method of the present invention is applied.

  FIG. 17 shows a portion where a base end portion of a B pillar (center pillar) between the front seat and the rear seat is connected to the side sill which is a frame constituting the body directly below the door of the automobile. ing. The side sill is a frame that needs to be strong enough to withstand a predetermined impact from the lateral direction of the automobile. The side sill inner 301 and the side sill outer 303 form a cylindrical shape as a whole, and the side sill inner 301 and the side sill outer 303 A side sill reinforcement 302 is provided for reinforcement. A pillar inner 307 constituting the B pillar is connected to the side sill inner 301, and an internal space between the side sill inner 301 and the side sill reinforcement 302 is provided to further improve the strength of the side sill before and after the B pillar. Are provided with gussets 304, 305, and 306 having a knot structure.

  Thus, the part provided with the gussets 304, 305, 306 surrounded by the side sill inner 301 and the side sill reinforcement 302 is a bag structure. Further, the plate thickness (1.4 mm or 1.6 mm) of the side sill inner 301 on the outer side of the bag structure portion is thicker than the plate thickness (1.0 mm) of the gussets 304, 305, and 306 on the inner side. With indirect spot welding, welding was difficult.

  Even with the bag structure as described above, high-quality spot welding can be performed with a simple configuration by applying the present invention. That is, spot welding can be performed by inserting and bending the welded pieces provided in the gussets 304, 305, and 306 in the side sill inner 301 provided with a long hole in advance.

  Next, the detailed structure of the gusset will be described. FIG. 18A is a perspective view showing a state before the welded piece of the gusset 304 in FIG. 17 is bent. The gusset 304 is integrally provided with a gusset main body 304a, flanges 304e and 304f for welding, and welded pieces 304b and 304c around it. The flange portions 304e and 304f are formed by being bent at a right angle to the gusset main body portion 304a, and the flange portion 304e and the flange portion 304f are perpendicular to each other. The welded pieces 304b and 304c are formed with two convex portions at the edge of the gusset main body 304a, and these convex portions are used as the welded pieces 304b and 304c. In addition, the structure which integrally provided these flange parts 304e and 304f and the to-be-welded pieces 304b and 304c around the gusset main-body part 304a is producible, for example by press molding from one board.

FIG. 18B shows a modification of the gusset 304 described above. As is apparent from the figure, the structures of the parts to be welded 304b and 304c are different, and the pieces to be welded 304b and 304c are formed by cutting and raising from a flange part 304d formed by bending the gusset body part 304a. .

  FIG. 19 is an enlarged cross-sectional view showing a welded portion of the gusset 304 of FIG. As described above, the gusset 304 having a knot structure is provided in the internal space between the side sill inner 301 and the side sill reinforcement 302. In order to produce this structure, first, the flange portions 304e and 304f of the gusset 304 are welded to the side sill reinforcement 302. Since welding of these portions is not a bag structure at this point, general spot welding is sufficient. The gussets 305 and 306 are also welded in the same manner. Next, the side sill inner 301 is covered so as to close the space in which the gussets 304 to 306 are provided. At this time, the pieces to be welded 304b and 304c of the gusset 304 are inserted into the elongated holes 301a provided in the side sill inner 301 in advance. Then, the pieces to be welded 304 b and 304 c protruding from the side sill inner 301 are bent at the same time using a bending tool so as to be parallel to the side sill inner 301. Subsequently, the pressurizing electrode 7 is brought into contact with one of the welded pieces 304b, the power feeding electrode 8 is brought into contact with another part of the side sill inner 301, and electricity is passed between these electrodes. Is brought into contact with the other welded piece 304c and energized between these electrodes. The gussets 305 and 306 are also welded in the same manner. As described above, spot welding between the side sill inner 301 and the gussets 304 to 306 can be performed.

  Here, FIG. 20 is an enlarged view showing a modification of the shape around the long hole which is opened in the side sill inner 401 of FIG. By processing the long hole, it is considered that the rigidity of the plate material around the long hole is insufficient, but in that case, by providing a bead (floating seat) in the portion where the long hole is provided, This lack of rigidity can be compensated.

  FIG. 20A is a plan view of a welded portion of the side sill inner 401 and the gusset 404 as viewed from above, and FIG. 20B is a cross-sectional view taken along the line AA in FIG. By providing the long hole 401a in the bead portion upper surface 401b that is floated from the periphery, the rigidity of the periphery can be increased even if the long hole is processed. Therefore, the gusset 404 is welded to the long hole 401a of the side sill inner 401. A side sill having the required rigidity can be obtained by inserting and bending the pieces 404b and 404c and spot welding.

  As described above, according to the present invention, spot welding of a bag structure portion or the like can be achieved with high quality by an easy bending process, and a welded piece to be a welded part is exposed to the outside of the bag structure portion. The state can be confirmed visually. Therefore, it may be suitably used in the field of an indirect spot welding method and its welding apparatus used for welding a bag structure portion or the like in a frame plate material constituting an automobile body.

DESCRIPTION OF SYMBOLS 1 Welding gun 2 Robot arm 3 Welding transformer 4 Gun mounting bracket 5 Air and servo stud gun 6 Electrode mounting point holder 7 Pressurizing electrode 8, 18 Feeding electrode 9 Bending plate mounting slide base plate 11, 21 Bending flat type Plates 31, 41 Folding roller type plates 101, 201 First plate members 101a, 201a, 201b Welded pieces 102, 202 Second plate members 102b, 202b Slotted holes 301, 401 Side sill inner 302 Side sill reinforcement 303 Side sill outer 304, 305 , 306, 404 Gusset 307 Pillar inner

Claims (10)

A pressure-side electrode is brought into contact with one member in a portion to be welded on which the first and second plate members are overlapped, and a power feeding side electrode is brought into contact with the other member in a portion separated from the portion to be welded. It is an indirect spot welding method for welding the first and second plate members at the welding target site by energizing in between,
While using a welding tool provided with a bending tool as a welding gun provided with the pressure electrode and the power feeding electrode,
A first step of arranging the first and second plate members so as to overlap each other in the welding target portion, using the second plate member provided with a piece to be welded in a standing state;
A second step of bending the welding piece with the bending tool so as to overlap the first plate at the site to be welded by moving the welding gun along the first plate;
The pressurizing electrode is welded to the piece to be welded bent in the second step, and the power feeding electrode is brought into contact with a portion of the first plate member that is separated from the welding target portion, and is then welded. An indirect spot welding method comprising a third step. In the invention according to claim 1,
In the second step, the bending tool having a guide groove is used, and the welding piece is bent while being guided by the guide groove. In the invention according to claim 1 or 2,
The indirect spot welding method, wherein the bending tool is provided integrally with the power feeding electrode. A pressure-side electrode is brought into contact with one member at a portion to be welded on which the first and second plate members are superimposed, and a power-feeding side electrode is brought into contact with the other member at a portion separated from the portion to be welded. It is an indirect spot welding method for welding the first and second plate members at the welding target site by energizing in between,
While using a welding tool provided with a bending tool as a welding gun provided with the pressure electrode and the power feeding electrode,
The first plate member is provided with a long hole, and the second plate member is provided with a stand-up welded piece, and the welded piece of the second plate member is passed through the long hole of the first plate member. However, a first step of arranging the first and second plate members so as to overlap each other at the site to be welded,
A second step of bending the welding piece with the bending tool so as to overlap the first plate at the site to be welded by moving the welding gun along the first plate;
The pressurizing electrode is welded to the piece to be welded bent in the second step, and the power feeding electrode is brought into contact with a portion of the first plate member that is separated from the welding target portion, and is then welded. An indirect spot welding method comprising a third step. In the invention according to claim 4,
The indirect spot welding method, wherein the bending tool is provided integrally with the power feeding electrode. In the invention which concerns on any one of Claims 1 thru | or 5,
The indirect spot welding method, wherein the second plate material is a plate material thinner than the first plate material. In the invention which concerns on any one of Claims 4 thru | or 6,
The indirect spot welding method, wherein the first plate member is a frame plate member of a vehicle body, and the second plate member is a reinforcing member disposed on the frame plate member. A pressure-side electrode is brought into contact with one member in a portion to be welded on which the first and second plate members are overlapped, and a power feeding side electrode is brought into contact with the other member in a portion separated from the portion to be welded. In an indirect spot welding apparatus that welds the first and second plate members at the welding target site by energizing in between,
A welding gun provided with a bending tool together with the pressing electrode and the feeding electrode;
With respect to the second plate member provided with the first plate member and the piece to be welded in an upright state, disposed so as to overlap in the welding target portion, the bending gun is moved by moving the welding gun along the first plate member. The welding piece is bent by a processing tool so as to overlap the first plate member at the welding target portion, and the pressurizing electrode is separated from the welding target portion in the first plate member by bending the welding piece. An indirect spot welding apparatus comprising: a control means for controlling welding by bringing the power supply electrodes into contact with each other and energizing them. In the invention according to claim 8,
The indirect spot welding apparatus, wherein the bending tool includes a guide groove for guiding the workpiece to be welded when bent. In the invention according to claim 8,
The indirect spot welding apparatus, wherein the bending tool is provided integrally with the power supply electrode.

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