Solid resistance spot bonding equipment

Abstract

To suppress drift current of current flowing in an electrode.SOLUTION: A pressurization shaft 100 presses a plurality of overlapped joined objects 2 from a first direction in a plastic deformable manner. An electrode 110 is arranged around the pressurization shaft 100, and applies a voltage to the plurality of joined objects 2. A connection conductor 180 is positioned closer to the drive source 30 than the electrode 110 in the first direction, and extends in a second direction perpendicular to the first direction. A plurality of wiring members 190 are provided so as to electrically connect the connection conductor 180 and the electrode 110. The connection conductor 180 has a base part 181, and an extension part 182. The base part 181 is positioned so as to cover the electrode 110 when being viewed from the first direction. The extension part 182 extends in the second direction from a part of an edge 183 of the base part 181. Each of the plurality of wiring members 190 has a first end 191, and a second end 192. The first end 191 is connected to a position other than the part of the edge 183 in the base part 181. The second end 192 is positioned on the side of the electrode 110.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a solid resistance spot bonding apparatus. [Background technology]

[0002] International Publication No. 2021 / 182444 (Patent Document 1) is a prior art document that discloses a solid-state resistance spot joining device. The solid-state resistance spot joining device described in Patent Document 1 includes a central pressure shaft, a copper electrode, and a bus bar. The central pressure shaft applies an external stress to the metal plate that is equal to or greater than the yield strength of the metal plate at the joining temperature. The copper electrode has a cylindrical shape and heats the metal plate by passing a current through it. The bus bar is connected to the entire circumference of the cylindrical copper electrode and extends from the copper electrode in a direction perpendicular to the axial direction of the central pressure shaft. A current flows from a power source to the copper electrode through the bus bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 182444 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, current tends to flow more in the shortest path of the current path. In the solid-state resistance spot joining device described in Patent Document 1, the portion of the copper electrode near the side where the bus bar extends is the shortest path of the current path, so the current flows concentrated in this path. This may cause the current flowing in the electrode to drift.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a solid-state resistance spot joining apparatus that can suppress the uneven flow of current flowing within the electrodes. [Means for solving the problem]

[0006] A solid-state resistance spot bonding apparatus according to the present invention includes a drive source and a bonding unit. The bonding unit is driven in a first direction by the drive source. The bonding unit includes a pressure shaft, an electrode, a connection conductor, and multiple wiring members. The pressure shaft presses the stacked objects to be bonded from the first direction in a manner that allows plastic deformation. The electrode is arranged around the pressure shaft and applies a voltage to the multiple objects to be bonded. The connection conductor is located closer to the drive source than the electrode in the first direction and extends in a second direction perpendicular to the first direction. The multiple wiring members are provided to electrically connect the connection conductor and the electrode. The connection conductor has a base and an extension. The base is located so as to cover the electrode when viewed from the first direction. The extension extends in the second direction from a portion of an edge of the base. Each of the multiple wiring members has a first end and a second end. The first end is connected to a position other than the portion of the edge of the base. The second end is located on the electrode side.

[0007] In this case, part of the current path for the current flowing into the electrode is formed by a plurality of wiring members connected to the edge of the base of the connecting conductor, and the plurality of wiring members are connected to the edge of the base other than the part to which the extension is connected. This allows the current to be diverted from the current path when the part of the edge of the connecting conductor connected to the extension of the base is connected to the electrode in the shortest distance, and the current can be passed from the connecting conductor to the electrode via the plurality of wiring members, thereby suppressing the biasing of the current flowing in the electrode.

[0008] In one aspect of the present invention, the first ends of the plurality of wiring members are connected to each other at equal intervals on the edge of the base when viewed from the first direction.

[0009] In this case, by arranging the current paths between the connection conductor and the plurality of wiring members at equal intervals around the axis in the first direction, it is possible to suppress current drift in the connections between the connection conductor and the plurality of wiring members.

[0010] In one aspect of the present invention, the second end is disposed at the same rotation angle as the first end around the electrode when viewed from the first direction.

[0011] In this case, the distance between the first end and the second end can be shortened, thereby shortening the path of the multiple wiring members and improving current flow efficiency. By arranging the points where current flows from the multiple wiring members to the electrode at equal intervals, it is possible to suppress current drift at the connection between the electrode and the multiple wiring members.

[0012] In one embodiment of the present invention, the joining unit further includes an elastic member and a case member. The elastic member urges the electrode toward the plurality of objects to be joined. The case member is positioned around the pressure shaft and houses the elastic member therein. The second end is positioned outward from the case member with the electrode as the center when viewed from the first direction.

[0013] In this case, by arranging the wiring members on the outside of the case member that houses the electrode drive mechanism using the elastic member, it is possible to prevent the driving operation of the electrodes from being hindered by the multiple wiring members.

[0014] In one embodiment of the present invention, the joining unit further includes a conductive plate-shaped member. The plate-shaped member extends outward from an outer edge of the electrode when viewed from the first direction and is connected to the second ends of each of the plurality of wiring members. The electrode is electrically connected to each of the plurality of wiring members via the plate-shaped member. The connection point between the second end and the plate-shaped member is located outside the case member with the electrode as the center when viewed from the first direction.

[0015] In this case, by making the plate-shaped member wider than the case member that houses the electrode driving mechanism using the elastic member, the multiple wiring members connected to the plate-shaped member can be positioned outside the case member, thereby preventing the multiple wiring members from interfering with the electrode driving operation. [Effects of the Invention]

[0016] According to the present invention, it is possible to suppress the uneven flow of the current flowing in the electrode. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a front view showing a configuration of a solid-state resistance spot joining apparatus according to an embodiment of the present invention; [Figure 2] 1 is a cross-sectional view showing a configuration of a joining unit and its surroundings of a solid-state resistance spot joining apparatus according to an embodiment of the present invention. [Figure 3] 3 is an enlarged cross-sectional view of part III in FIG. 2, showing the state of the apparatus before the objects to be bonded are bonded. [Figure 4] 1 is a perspective view showing a configuration of a connecting conductor and a wiring member in a first joining unit of a solid-state resistance spot joining apparatus according to an embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a bottom view showing a current path to an electrode in the solid-state resistance spot joining apparatus according to the embodiment of the present invention. [Figure 6] 1 is a cross-sectional view showing a state of the solid-state resistance spot joining device according to an embodiment of the present invention immediately after objects to be joined are joined by the device. DETAILED DESCRIPTION OF THE INVENTION

[0018] A solid resistance spot joining apparatus according to one embodiment of the present invention will now be described with reference to the drawings. In the following description of the embodiment, the same or corresponding parts in the drawings will be given the same reference numerals, and description thereof will not be repeated.

[0019] In the drawings, the direction perpendicular to the axial direction of the pressure shaft and parallel to the extension direction of the connection conductor is defined as the X direction, which is the second direction. The axial direction of the pressure shaft is defined as the Y direction, which is the first direction. Furthermore, the direction perpendicular to the axial direction of the pressure shaft and the extension direction of the connection conductor is defined as the Z direction, which is the third direction.

[0020] Fig. 1 is a front view showing the configuration of a solid-state resistance spot joining apparatus according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view showing the configuration of the periphery of a joining unit of the solid-state resistance spot joining apparatus according to an embodiment of the present invention.

[0021] As shown in Figures 1 and 2, a solid-state resistance spot joining apparatus 1 according to one embodiment of the present invention is an apparatus that forms softened regions in a plurality of overlapping workpieces 2 by passing an electric current through the workpieces 2, and then plastically deforms the softened regions to join the plurality of workpieces 2 together while maintaining the workpieces 2 in a solid state.

[0022] The solid-state resistance spot joining apparatus 1 includes a first joining unit 10, a second joining unit 20, a drive source 30, and a power supply unit 40.

[0023] The first bonding unit 10 is a unit for pressing the plurality of articles 2 to be plastically deformable, and for applying a voltage to the plurality of articles 2. The first bonding unit 10 is driven in a first direction (Y direction) by a drive source 30. The configuration of the first bonding unit 10 will be described later.

[0024] The second joining unit 20 is a unit that presses the plurality of objects 2 together with the first joining unit 10 and applies a voltage to the plurality of objects 2. The second joining unit 20 is fixed to the housing of the solid-state resistance spot joining apparatus 1.

[0025] 2, the second joining unit 20 in this embodiment is plane-symmetrical with respect to the XZ plane with respect to the first joining unit 10 and has the same configuration as the first joining unit 10. Note that the second joining unit 20 is not limited to this configuration, and may have a configuration in which, for example, an elastic member 150 described below is not provided.

[0026] 1, the driving source 30 drives the first joining unit 10 in the Y direction. The driving source 30 in this embodiment is, for example, a servo press machine.

[0027] The power supply unit 40 applies a voltage to the first joining unit 10 and the second joining unit 20. The power supply unit 40 has a power supply side conductor 41. The power supply side conductor 41 is connected to each of the first joining unit 10 and the second joining unit 20.

[0028] The workpieces 2 to be joined by the solid-state resistance spot joining apparatus 1 are, for example, steel plates such as high-tensile steel plates. Note that the workpieces 2 are not limited to steel plates, and may be aluminum plates or the like, or may be made of dissimilar materials such as steel plates and aluminum plates.

[0029] The first joining unit 10 will be described below. Fig. 3 is an enlarged cross-sectional view of part III in Fig. 2, showing the state of the apparatus before the workpieces are joined. Fig. 4 is a perspective view showing the configuration of a connecting conductor and a wiring member in a first joining unit of a solid-state resistance spot joining apparatus according to an embodiment of the present invention. Fig. 5 is a bottom view showing a current path to an electrode in a solid-state resistance spot joining apparatus according to an embodiment of the present invention.

[0030] 2 to 5, the first joining unit 10 in one embodiment of the present invention includes a pressure shaft 100, an electrode 110, a base member 120, a case member 130, a lid portion 140, a sphere 142, an elastic member 150, a guide member 160, a plate-like member 170, a connecting conductor 180, and a plurality of wiring members 190. The elastic member 150 in this embodiment has a plurality of first elastic members 151 and one second elastic member 152.

[0031] The pressure shaft 100 is a cylindrical member extending in the Y direction. The material of the pressure shaft 100 is, for example, tungsten carbide. However, the material of the pressure shaft 100 is not particularly limited as long as it can apply the necessary pressing force to the article 2, and may be tool steel, heat-resistant steel, ceramics, or the like.

[0032] As shown in Fig. 3, the pressure shaft 100 has a front end 101 and a rear end 102. The front end 101 is a portion that comes into contact with an article 2a that is located on the first joining unit side among the plurality of articles 2. The rear end 102 is connected to a holder 103 that supports the pressure shaft 100. The rear end 102 has a tapered shape and engages with the inner circumferential surface of the holder 103.

[0033] The pressing shaft 100 presses the stacked articles 2 from a first direction (Y direction) in a manner that allows plastic deformation. Specifically, the pressing shaft 100 of the present embodiment presses the articles 2 with a pressing force of 30 to 50 kN by being driven by the drive source 30.

[0034] The electrode 110 is driven together with the pressure applying shaft 100 by the driving source 30. The electrode 110 is arranged around the pressure applying shaft 100 with a gap therebetween. In this embodiment, the tip 111 of the electrode 110 has a cylindrical shape when viewed from the Y direction.

[0035] The electrode 110 has electrical conductivity. The electrode 110 is made of, for example, copper. The electrode 110 applies a voltage to the plurality of objects to be bonded 2. By applying the voltage to the plurality of objects to be bonded 2, the electrode 110 passes a current of 3500 to 10000 A through the plurality of objects to be bonded 2, thereby heating the plurality of objects to be bonded 2.

[0036] The base member 120 is conductive and extends in a first direction (Y direction). The base member 120 is made of, for example, copper. The base member 120 is disposed around the pressing shaft 100 with a gap therebetween.

[0037] The base member 120 has a main body portion 121, a connection end portion 122, and a flange portion 123. The main body portion 121 is a cylindrical portion of the base member 120 that extends in the Y direction.

[0038] The connection end 122 is located on the article 2 side in the Y direction of the main body 121. The connection end 122 extends in the first direction (Y direction) with a gap therebetween so as to surround the pressurizing shaft 100. The connection end 122 is connected to the electrode 110.

[0039] The flange portion 123 extends on the XZ plane from the end portion of the main body portion 121 opposite to the side where the connection end portion 122 is disposed. The flange portion 123 is aligned with the plurality of first elastic members 151 in the first direction (Y direction).

[0040] The flange portion 123 has a contact surface 124. The flange portion 123 is in contact with the plurality of first elastic members 151 at the contact surface 124.

[0041] A first recess 125 is provided on the lid 140 side of the flange 123. The first recess 125 according to this embodiment has a conical surface shape. Note that the shape of the first recess 125 is not limited to a conical surface, and it may be a curved surface.

[0042] The range in which the electrode 110 can tilt in the first direction (Y direction) is defined by the gap between the electrode 110 and the base member 120 and the pressure shaft 100. Therefore, when the article 2 extending in the XZ plane tilts with respect to the XZ plane, the electrode 110 and the base member 120 can tilt with respect to the Y direction while the electrode 110 is in contact with the article 2.

[0043] The case member 130 is positioned around the pressure shaft 100 and houses therein a plurality of first elastic members 151 and one second elastic member 152. The case member 130 is made of, for example, an insulating material.

[0044] The case member 130 is provided with a groove 131 extending along the first direction (Y direction). A plurality of first elastic members 151 are housed in the groove 131. The case member 130 abuts against the elastic members 150 from the side opposite to the electrode 110 in the first direction (Y direction).

[0045] Lid portion 140 is a member that supports flange portion 123 via spheres 142. Lid portion 140 faces flange portion 123 and is connected to the end of case member 130 on the electrode 110 side. Lid portion 140 is made of, for example, steel.

[0046] A second recess 141 is provided on the flange portion 123 side of the lid portion 140. The second recess 141 according to this embodiment has a conical surface shape. Note that the shape of the second recess 141 is not limited to a conical surface shape, and it may also be a curved surface.

[0047] The spheres 142 are disposed between the lid portion 140 and the flange portion 123. The spheres 142 are, for example, steel balls. A plurality of the spheres 142 are disposed in line with the plurality of first elastic members 151 in the Y direction so as to correspond to each of the plurality of first elastic members 151.

[0048] The sphere 142 can be in line contact with each of the first recess 125 and the second recess 141. This reduces the contact resistance between the flange portion 123 and the sphere 142, making it easier for the electrode 110 and the base member 120 to tilt in the Y direction. Furthermore, the line contact of the sphere 142 makes it difficult for heat generated by current flow to the electrode 110 to be transferred from the flange portion 123 to the lid portion 140, thereby improving the heat resistance of the first joint unit 10.

[0049] The elastic member 150 urges the electrode 110 toward the plurality of articles 2. In this embodiment, the electrode 110 is urged by the elastic member 150 to press the plurality of articles 2 with a pressing force of, for example, 1 to 2 kN.

[0050] The plurality of first elastic members 151 in the elastic member 150 are arranged around the pressure shaft 100 at intervals from one another, and urge the electrode 110 toward the plurality of objects 2. Specifically, the plurality of first elastic members 151 abut against the contact surface 124 of the flange portion 123 of the base member 120, and urge the electrode 110 via the base member 120.

[0051] Each of the plurality of first elastic members 151 has an elastic body 153 and a base portion 154. In this embodiment, the elastic body 153 is, for example, a spring. Note that the elastic body 153 is not limited to a spring, and may be another elastic body such as rubber.

[0052] Pedestal portion 154 is disposed at the end of elastic body 153 on the side of base member 120. Pedestal portion 154 in this embodiment is, for example, a spring bearing.

[0053] One second elastic member 152 is disposed inside the multiple first elastic members 151 around the pressure shaft 100. One second elastic member 152 is, for example, a spring. Note that the second elastic member 152 is not limited to a spring and may be another elastic body such as rubber.

[0054] The one second elastic member 152 biases the electrode 110 toward the plurality of articles 2 to be bonded via the guide member 160. The one second elastic member 152 has a role of correcting the inclination of the base member 120 on the XZ plane when the first bonding unit 10 is separated from the articles 2 to be bonded after the base member 120 has been bonded at an inclination with respect to the XZ plane.

[0055] The guide member 160 is disposed around the pressure applying shaft 100 with a gap therebetween. The guide member 160 is provided with a plurality of through holes 161 penetrating in a first direction (Y direction). A corresponding one of the plurality of first elastic members 151 is inserted into each of the plurality of through holes 161. In this way, the guide member 160 supports each of the plurality of first elastic members 151.

[0056] The plate-shaped member 170 is conductive and extends outward from the outer edge of the electrode 110 when viewed from the first direction (Y direction). The plate-shaped member 170 in this embodiment is connected to the circumferential surface of the main body 121 of the base member 120.

[0057] A flow path 171 through which cooling water flows is provided inside the plate-shaped member 170. The electrode 110 and the plate-shaped member 170 can be cooled by the cooling water flowing through the flow path 171. Note that the plate-shaped member 170 does not necessarily have to be provided with the flow path 171.

[0058] The connecting conductor 180 is located closer to the driving source 30 than the electrode 110 in the first direction (Y direction), and extends in a second direction (X direction) perpendicular to the first direction (Y direction).

[0059] As shown in FIGS. 4 and 5, a connecting conductor 180 in this embodiment has a base portion 181 and an extending portion 182.

[0060] The base 181 is positioned so as to cover the electrode 110 when viewed from the first direction (Y direction). The base 181 in this embodiment is positioned so as to cover the electrode 110 and the plate-like member 170 when viewed from the Y direction. The base 181 has an octagonal edge 183 when viewed from the Y direction.

[0061] The extending portion 182 extends in the second direction (X direction) from a part of the edge 183 of the base portion 181. In the present embodiment, an imaginary boundary 184 is defined on one side of the octagonal edge 183 of the base portion 181, and the extending portion 182 extends in the X direction from the imaginary boundary 184. Note that the extending direction of the extending portion 182 is not limited to the X direction, and the extending portion 182 may extend in a direction other than the X direction on the XZ plane.

[0062] The extension portion 182 is connected to the power supply side conductor 41 at an end opposite to the end connected to the base portion 181 extending in the X direction. This allows current to flow from the power supply unit 40 to the connection conductor 180.

[0063] The width of base 181 in the Z direction is greater than the width of extension 182. This prevents current I that flows from extension 182 into base 181 from concentrating and drifting inside base 181.

[0064] The plurality of wiring members 190 are provided to electrically connect the connection conductor 180 and the electrode 110. In the present embodiment, each of the plurality of wiring members 190 is electrically connected to the electrode 110 via the plate-like member 170 and the base member 120. The wiring members 190 are made of, for example, copper wires.

[0065] The plurality of wiring members 190 includes a first wiring member 190a, a second wiring member 190b, a third wiring member 190c, and a fourth wiring member 190d. The number of the plurality of wiring members 190 is not limited to four, and it is desirable that the plurality of wiring members 190 be composed of at least three wiring members in order to suppress bias current within the electrode 110.

[0066] Each of the plurality of wiring members 190 has a first end 191 and a second end 192. The first end 191 is connected to a position other than a part of the edge 183 of the base 181 to which the extending portion 182 is connected.

[0067] The second end 192 is located on the electrode 110 side. The second end 192 of each of the plurality of wiring members 190 is connected to the plate-shaped member 170.

[0068] When viewed from the first direction (Y direction), the first ends 191 of the wiring members 190 are connected to one another at equal intervals on the edge 183 of the base 181.

[0069] When viewed from the first direction (Y direction), the second end 192 is disposed at the same rotation angle as the first end 191 around the electrode 110. When viewed from the first direction (Y direction), the second end 192 is located outside the case member 130 around the electrode 110. Specifically, when viewed from the first direction (Y direction), the connection point between the second end 192 and the plate-like member 170 is located outside the case member 130 around the electrode 110.

[0070] The current I supplied from the power supply unit 40 flows through the power supply side conductor 41, the connecting conductor 180, the plurality of wiring members 190, the plate-like member 170, the base member 120, and the electrode 110 in this order.

[0071] In general, current I tends to flow more in the shortest path of the current path. If the entire periphery of edge 183 of base 181 and the entire periphery of plate-shaped member 170 are connected by a wiring member, the wiring member connected to imaginary boundary 184 constitutes the shortest path of the current path. In this case, current I flows from imaginary boundary 184 of edge 183 of base 181 to plate-shaped member 170. For this reason, current I may flow from the side closer to imaginary boundary 184 to electrode 110, causing current I to drift within electrode 110.

[0072] On the other hand, in the present embodiment, the current I branches and flows through the multiple wiring members 190. Specifically, the current I that has flowed into the multiple wiring members 190 branches, with current Ia flowing in first wiring member 190a, current Ib flowing in second wiring member 190b, current Ic flowing in third wiring member 190c, and current Id flowing in fourth wiring member 190d. This allows the current I to be diverted from the current path that would connect electrode 110 to a part of edge 183 connected to extending portion 182 of base 181 of connecting conductor 180 in the shortest possible manner, and current I can be passed from connecting conductor 180 to electrode 110 via the multiple wiring members 190. As a result, it is possible to suppress uneven flow of the current I flowing within electrode 110.

[0073] In the solid-state resistance spot bonding apparatus 1, the contact resistance is reduced by the objects 2a, 2b coming into close contact with each other at their contact surfaces due to the pressing of the pressure shaft 100 and the electrode 110 against the objects 2. As a result, the current I that has flowed into the electrode 110 flows from the electrode 110 to the contact surface where the contact resistance is reduced.

[0074] Hereinafter, a description will be given of solid-state resistance spot welding of the workpieces 2 by the solid-state resistance spot welding apparatus 1. Fig. 6 is a cross-sectional view showing the state of the apparatus immediately after the workpieces are joined by the solid-state resistance spot welding apparatus according to one embodiment of the present invention.

[0075] In the operation of solid-state resistance spot bonding of the objects 2 by the solid-state resistance spot bonding apparatus 1, first, as shown in FIGS. 1 to 3, the drive source 30 drives the first bonding unit 10, thereby bringing the electrode 110 into contact with the object 2a, of the plurality of objects 2, that is located on the electrode 110 side of the first bonding unit 10.

[0076] Next, a voltage is applied to the plurality of objects 2 from the electrode 110. The contact surfaces where the objects 2 are in close contact with each other and the contact resistance is reduced become current paths, and a current I flows through the current paths. As a result, the plurality of objects 2 are heated, and softened regions R are formed between the plurality of objects 2.

[0077] Next, as shown in FIG. 6, the electrode 110 is pressed against the plurality of articles 2 by the biasing force of the elastic member 150, and the pressing shaft 100 is pressed against the plurality of articles 2.

[0078] Specifically, the driving source 30 further drives the first joining unit 10, thereby causing the pressure shaft 100 to plastically deform the softened regions R between the objects 2. At this time, the electrode 110 is biased by the elastic member 150 via the base member 120, and therefore is driven independently of the pressure shaft 100 in the first joining unit 10, and presses the plurality of objects 2 by the biasing force of the elastic member 150. By driving the electrode 110, a gap is created in the Y direction between the first recess 125 of the flange portion 123 and the sphere 142.

[0079] When the electrode 110 applies current to the article 2 and the pressurizing shaft 100 presses the article 2, the softened region R of the article 2 undergoes plastic deformation. The article 2 undergoes plastic deformation while creating a gap between the articles 2a, 2b at positions other than the softened region R. Due to the plastic deformation of the softened region R, a new surface is formed in the softened region R. When these new surfaces come into contact with each other, the articles 2a, 2b are solid-state resistance spot joined to each other.

[0080] The order in which the pressure shaft 100 and the electrode 110 come into contact with the article 2a is not limited. The pressure shaft 100 may come into contact with the article 2a before the electrode 110, or the pressure shaft 100 and the electrode 110 may come into contact with the article 2a at the same time.

[0081] In the solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, a portion of the current path of the current I flowing into the electrode 110 is formed by a plurality of wiring members 190 connected to an edge of the base 181 of the connecting conductor 180, and the plurality of wiring members 190 are connected to an edge 183 of the base 181 other than the portion to which the extending portion 182 is connected. This allows the current I to be diverted from the current path that would otherwise be taken when connecting the electrode 110 to the portion of the edge 183 of the connecting conductor 180 connected to the extending portion 182 of the base 181 in the shortest possible manner, and allows the current I to flow from the connecting conductor 180 to the electrode 110 via the plurality of wiring members 190. This makes it possible to suppress uneven flow of the current I flowing in the electrode 110.

[0082] In a solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, the current paths between the connecting conductor 180 and the plurality of wiring members 190 are arranged at equal intervals around the axis of the first direction (Y direction), thereby suppressing the drift of current I in the connection between the connecting conductor 180 and the plurality of wiring members 190.

[0083] In the solid-state resistance spot bonding apparatus 1 according to an embodiment of the present invention, the distance between the first end 191 and the second end 192 can be shortened, thereby shortening the path of the multiple wiring members 190 and improving current flow efficiency. By arranging the points at which the current I flows from the multiple wiring members 190 to the electrode 110 at equal intervals, it is possible to suppress uneven flow of the current I in the connection between the electrode 110 and the multiple wiring members 190.

[0084] In the solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, by arranging the wiring member 190 outside the case member 130 that houses the drive mechanism for the electrode 110 using the elastic member 150, it is possible to prevent the drive operation of the electrode 110 from being hindered by the multiple wiring members 190. Specifically, by making the plate-shaped member 170 wider than the case member 130 that houses the drive mechanism for the electrode 110 using the elastic member 150, it is possible to arrange the multiple wiring members 190 connected to the plate-shaped member 170 outside the case member 130, thereby preventing the drive operation of the electrode 110 from being hindered by the multiple wiring members 190.

[0085] In the solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, by providing a flow path 171 through which cooling water flows in the plate-shaped member 170, the plate-shaped member 170 can be cooled by the cooling water, thereby suppressing the temperature rise of the electrode 110 and the plate-shaped member 170, which generate heat when current is applied.

[0086] In this embodiment, a so-called direct bonding method has been described in which a pair of electrodes are arranged in one direction and the objects to be bonded are sandwiched between the pair of electrodes, but the present invention is not limited to the direct method and can also be applied to other resistance bonding methods such as the indirect method or the series method.

[0087] Furthermore, in this embodiment, a stationary solid resistance spot welding apparatus has been described, but the present invention is not limited to this configuration and can also be applied to a gun-type welding apparatus.

[0088] It should be noted that the above-described embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. In the description of the above-described embodiments, combinable configurations may be combined with each other. [Explanation of symbols]

[0089] 1 solid-state resistance spot joining device, 2, 2a, 2b workpieces, 10 first joining unit, 30 driving source, 100 pressure shaft, 110 electrode, 130 case member, 150 elastic member, 170 plate-shaped member, 171 flow path, 180 connecting conductor, 181 base, 182 extension portion, 183 edge, 190 multiple wiring members, 191 first end, 192 second end, I, Ia, Ib, Ic, Id current.

Claims

1. A driving source; a joining unit driven in a first direction by the drive source, The joining unit is a pressure shaft that presses the stacked objects from the first direction in a manner that allows plastic deformation; an electrode disposed around the pressure shaft and configured to apply a voltage to the plurality of objects to be bonded; a connecting conductor located closer to the driving source than the electrode in the first direction and extending in a second direction perpendicular to the first direction; a plurality of wiring members for electrically connecting the connection conductors and the electrodes; The connecting conductor is a base portion positioned to cover the electrode when viewed from the first direction; an extension portion extending in the second direction from a part of an edge of the base portion, Each of the plurality of wiring members is a first end connected to the base at a position other than a part of the edge; a second end located on the electrode side.

2. 2. The solid-state resistance spot joining apparatus according to claim 1, wherein the first ends of the plurality of wiring members are connected to each other at equal intervals on the edge of the base when viewed from the first direction.

3. The solid-state resistance spot joining apparatus according to claim 2 , wherein the second end is disposed at the same rotation angle as the first end around the electrode when viewed from the first direction.

4. The joining unit is an elastic member that biases the electrode toward the plurality of objects to be bonded; a case member positioned around the pressure shaft and accommodating the elastic member therein, 4. The solid-state resistance spot joining device according to claim 1, wherein the second end is located outward from the case member with the electrode at the center when viewed from the first direction.

5. The joining unit is the second end of each of the plurality of wiring members is connected to the second end of the electrode, and the second end of the plurality of wiring members is connected to the second end of the electrode. the electrodes are electrically connected to the plurality of wiring members via the plate-like member, 5. The solid-state resistance spot joining device according to claim 4, wherein a connection point between the second end and the plate-like member is located outside the case member with the electrode as the center when viewed from the first direction.

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