Solid resistance spot bonding equipment

Abstract

To bring an electrode into uniform contact with joined objects, when the joined objects are arranged so as to be inclined.SOLUTION: A plurality of first elastic members 151 are arranged at intervals around a pressurization shaft 100, and energize an electrode 110 toward a plurality of joined objects 2. A drive source 30 drives a joining unit 10, and thereby brings the electrode 110 into contact with the joined object 2a positioned on the side of the electrode 110 out of the plurality of joined objects 2, and presses the pressurization shaft 100 against the plurality of joined objects 2 while pressing the electrode 110 against the plurality of joined objects 2 by each energization force of the plurality of first elastic members 151. The electrode 110 is supported in a posture changeable so as to be brought into contact, following its contact surface, with the joined object 2 positioned on the side of the electrode 110. Each of the plurality of first elastic members 151 is elastically deformed according to the attitude of the electrode 110 when being brought into contact with the joined object 2a positioned on the side of the electrode 110.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] A prior art document disclosing a solid-state resistance spot joining apparatus is International Publication No. 2021 / 182444 (Patent Document 1). The solid-state resistance spot joining apparatus described in Patent Document 1 includes a central pressure shaft and a copper electrode. 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 heats the metal plate by passing a current through it. The copper electrode is controlled by a separate drive from the central pressure shaft. The electrode is driven by an air cylinder to apply a load to the metal plate. [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] In the solid-state resistance spot bonding apparatus described in Patent Document 1, an electrode pressed against the workpiece by an air cylinder is driven in the axial direction of a central pressure shaft. If the workpiece extends in a direction perpendicular to this axial direction and is placed at an angle, the electrode may make uneven contact with the workpiece.

[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 device that can bring electrodes into uniform contact with the workpieces when the workpieces are placed at an angle. [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 an axial direction by the drive source. The bonding unit includes a pressure shaft, an electrode, and a plurality of first elastic members. The pressure shaft presses the stacked objects in the axial direction in a manner that allows plastic deformation. The electrode is arranged around the pressure shaft with a gap therebetween and applies a voltage to the objects. The plurality of first elastic members are arranged around the pressure shaft with a gap therebetween and bias the electrode toward the objects. The drive source drives the bonding unit to bring the electrode into contact with an object located on the electrode side among the multiple objects, and the biasing force of each of the multiple first elastic members presses the electrode against the multiple objects, while pressing the pressure shaft against the multiple objects. The electrode is supported in a position that can be changed so that it abuts along a contact surface with the object located on the electrode side. Each of the plurality of first elastic members is elastically deformed according to the posture of the electrode when it comes into contact with the article located on the electrode side.

[0007] In this case, by arranging a plurality of first elastic members around the pressure shaft and biasing the electrodes, when the objects to be bonded are placed at an angle, each of the plurality of first elastic members can elastically deform in accordance with the angle of the objects to be bonded. This allows the electrodes to be inclined with respect to the axial direction of the pressure shaft, so that when the objects to be bonded are placed at an angle, the electrodes can be brought into uniform contact with the objects to be bonded.

[0008] In one embodiment of the present invention, the joining unit further includes a base member. The base member extends in the axial direction with a gap therebetween so as to surround the pressure shaft, and has a connection end connected to the electrode and a flange portion aligned with the plurality of first elastic members in the axial direction. Each of the plurality of first elastic members abuts against the flange portion and biases the electrode via the base member. The range within which the electrode can tilt with respect to the axial direction is determined by the gap between the electrode and the base member and the pressure shaft.

[0009] In this case, by providing a base member and abutting multiple first elastic members against the flange portion of the base member, the multiple first elastic members can be abutted over a wider area compared to when the multiple first elastic members are abutted directly against the electrode, and the electrode can be stably biased by the multiple first elastic members via the base member.

[0010] In one embodiment of the present invention, the joining unit further includes a guide member. The guide member is arranged around the pressure shaft with a gap therebetween and supports the plurality of first elastic members. The guide member is provided with a plurality of through holes penetrating in the axial direction. A corresponding one of the plurality of first elastic members is inserted into each of the plurality of through holes.

[0011] In this case, by providing a guide member, it is possible to prevent the positional deviation of the plurality of first elastic members.

[0012] In one embodiment of the present invention, the joining unit further includes a second elastic member that is disposed inside the first elastic members around the pressing shaft and urges the electrode toward the objects via the guide member.

[0013] In this case, by biasing the electrode from near the center with one second elastic member, when the electrode is separated from the objects to be bonded after the objects are bonded, the electrode that has tilted in response to the objects to be bonded can be corrected from the tilted state to its original state.

[0014] In one embodiment of the present invention, the joining unit further includes a case member, a lid, and a sphere. The case member is positioned around the pressurizing shaft, houses a plurality of first elastic members therein, and abuts against the plurality of first elastic members from the side opposite the electrode in the axial direction. The lid is connected to the electrode side end of the case member while facing the flange. The sphere is disposed between the lid and the flange. A first recess is provided on the lid side of the flange. A second recess is provided on the lid side of the flange. The sphere is capable of line contact with each of the first recess and the second recess.

[0015] In this case, by making the contact between the base member and the lid portion a line contact, the contact resistance of the contacting members can be reduced, making it easier to tilt the electrode relative to the object to be bonded. [Effects of the Invention]

[0016] According to the present invention, when the article to be bonded is placed at an angle, the electrodes can be brought into uniform contact with the article to be bonded. [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 around a plurality of first elastic members in a first joining unit of a solid-state resistance spot joining device in accordance with an embodiment of the present invention. FIG. [Figure 5] 1 is a cross-sectional view showing a state of the solid-state resistance spot welding apparatus according to an embodiment of the present invention immediately after objects to be welded are welded by the apparatus. FIG. [Figure 6] FIG. 2 is a schematic diagram showing a configuration of a first joining unit of a solid-state resistance spot joining apparatus according to an embodiment of the present invention when an electrode is tilted. [Figure 7] FIG. 10 is a cross-sectional view showing a configuration of a solid-state resistance spot joining apparatus according to a modified example of an embodiment of the present invention. 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 extending direction of the connecting conductor is defined as the X direction, the axial direction of the pressure shaft is defined as the Y direction, and the direction perpendicular to the axial direction of the pressure shaft and the extending direction of the connecting conductor is defined as the Z 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 and a second joining unit 20 as joining units, 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 the axial 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 plurality of first elastic members and their surroundings in the first joining unit of a solid-state resistance spot joining apparatus according to an embodiment of the present invention. In Fig. 4, the case member is shown in a see-through manner to facilitate understanding of the invention.

[0030] 2 to 4, 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 wiring member 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 pressure shaft 100 presses the stacked articles 2 from the axial direction (Y direction) in a manner that allows plastic deformation. Specifically, the pressure shaft 100 of this embodiment presses the articles 2 with a pressing force of 30 to 50 kN when 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 electrically conductive and extends in the axial 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 axial 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 axial 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 axial 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 is tilted 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] 2 to 4, 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] 3 and 4, the case member 130 is provided with a plurality of grooves 131 extending along the axial direction (Y direction). A plurality of first elastic members 151 is housed in each of the plurality of grooves 131. The case member 130 abuts against the plurality of first elastic members 151 from the side opposite to the electrode 110 in the axial 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. The spheres 142 are arranged 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 are arranged around the pressure shaft 100 at intervals from one another, and urge the electrode 110 toward the plurality of objects to be bonded 2. Specifically, the plurality of first elastic members 151 abut against the flange portion 123 of the base member 120, and urge the electrode 110 via the base member 120.

[0051] In this embodiment, eight first elastic members 151 are arranged at equal intervals on the circumference of the XZ plane centered on the pressure axis 100. The number of first elastic members 151 is not limited to eight, and may be at least three as long as the electrode 110 and the base member 120 can be tilted in either direction with respect to the Y direction.

[0052] 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.

[0053] 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.

[0054] The pedestal portion 154 has a spherical surface 155 on the base member 120 side. The spherical surface 155 is in point contact with the contact surface 124 of the flange portion 123. As a result, when the contact surface 124 is inclined with respect to the XZ plane, it is possible to prevent the pedestal portion 154 from making one-sided contact with the contact surface 124 and to prevent the application of biased biasing force from the multiple first elastic members 151 to the contact surface 124, compared to when the pedestal portion 154 is cylindrical.

[0055] 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.

[0056] The one second elastic member 152 biases the electrode 110 toward the plurality of articles 2 via the guide member 160. The one second elastic member 152 has a role of correcting the inclination of the base member 120 when the first joining unit 10 is separated from the articles 2 after the electrode 110 and the base member 120 have joined the articles 2 while inclined with respect to the XZ plane.

[0057] It is desirable that the Young's modulus in the Y direction of each of the plurality of first elastic members 151 is higher than that of one second elastic member 152. This makes it possible to easily bring the electrode 110 into close contact with the article 2 by the biasing force of the plurality of first elastic members 151 when the electrode 110 and the base member 120 are inclined from the Y direction.

[0058] 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 that penetrate in the axial 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.

[0059] The position of the guide member 160 is fixed by being biased in the Y direction by one second elastic member 152. One second elastic member 152 can simply fix the position of the guide member 160 without using a fixing method such as bolt fastening.

[0060] The plate-shaped member 170 is conductive and connected to the peripheral surface of the main body 121 of the base member 120. The connection conductor 180 is fixed to the driving source 30 side of the first joint unit 10. One end of the connection conductor 180 is connected to the power supply side conductor 41. The wiring member 190 electrically connects the plate-shaped member 170 and the connection conductor 180. The wiring member 190 is made of, for example, copper wire.

[0061] The current supplied from the power supply unit 40 flows in the order of the power supply side conductor 41, the connecting conductor 180, the wiring member 190, the plate-like member 170, the base member 120, and the electrode 110, and then flows to the article 2. In the solid-state resistance spot welding apparatus 1, the pressing of the pressure shaft 100 and the electrode 110 against the article 2 brings the articles 2a, 2b into close contact with each other at their contact surfaces, thereby reducing the contact resistance. As a result, the contact surfaces with reduced contact resistance become a current path, and current flows through the current path.

[0062] It should be noted that one second elastic member 152 is not necessarily required in the first joint unit 10. When one second elastic member 152 is not provided in the first joint unit 10, the guide member 160 is fixed to the base member 120 by a known connection method such as bolt fastening.

[0063] 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. 5 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.

[0064] 1 to 3, the movement of the solid-state resistance spot bonding of the objects to be bonded 2 by the solid-state resistance spot bonding apparatus 1 is as follows: first, the drive source 30 drives the first bonding unit 10, thereby bringing the electrode 110 into contact with an object to be bonded 2a, of the plurality of objects to be bonded, which is located on the electrode 110 side of the first bonding unit 10. By bringing the electrode 110 into contact with the object to be bonded 2a before the pressure shaft 100 and applying a preload, the object to be bonded 2 can be provisionally positioned. Furthermore, the electrode 110 of the second bonding unit 20 comes into contact with an object to be bonded 2b, of the plurality of objects to be bonded 2.

[0065] 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 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.

[0066] Next, as shown in FIG. 4, the electrode 110 is pressed against the plurality of articles 2 by the biasing force of each of the plurality of first elastic members 151, and the pressing shaft 100 is pressed against the plurality of articles 2.

[0067] 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.

[0068] 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.

[0069] There is no limitation on the order in which the pressure shaft 100 and the electrode 110 come into contact with the article 2. The pressure shaft 100 may come into contact with the article 2 before the electrode 110, or the pressure shaft 100 and the electrode 110 may come into contact with the article 2 at the same time.

[0070] FIG. 6 is a schematic diagram showing a configuration when the electrode in the first joining unit of the solid-state resistance spot joining device according to one embodiment of the present invention is tilted.

[0071] As shown in Figure 6, when joining the workpieces 2 using the above-mentioned solid-state resistance spot joining apparatus 1, the workpieces 2 may be positioned at an angle to the XZ plane due to positional deviation when positioning the workpieces 2 relative to the solid-state resistance spot joining apparatus 1 or variations in thickness of the workpieces 2.

[0072] If the electrode is driven in the Y direction by an air cylinder or the like, the surface of the tip of the electrode that comes into contact with the article 2 is parallel to the XZ plane. Therefore, if the article 2 is placed at an angle to the XZ plane, the surface of the tip of the electrode that comes into contact with the article 2 may come into uneven contact with the article 2, for example, by making one-sided contact with the article 2. As a result, the electrode does not apply uniform pressure to the contact surfaces of the articles 2a and 2b, so a uniform current path cannot be ensured, and a softened region cannot be ensured, which may cause poor welding.

[0073] 6, the electrode 110 in this embodiment is supported so as to be able to change its posture so as to abut along the contact surface with the article 2a located on the electrode 110 side. This allows the electrode 110 to be tilted with respect to the axial direction (Y direction) of the pressure shaft 100, so that when the article 2 is placed at an angle, the electrode 110 can be brought into uniform contact with the article 2. As a result, a current path between the electrode 110 and the article 2 is secured, so that a softened region R can be formed uniformly in the article 2, thereby suppressing the occurrence of poor bonding.

[0074] Furthermore, if the electrode is biased by one elastic member, the one elastic member is elastically deformed mainly in the Y direction. Therefore, if the article 2 is disposed tilted with respect to the XZ plane, it is difficult to tilt the electrode in accordance with the tilt of the article 2.

[0075] On the other hand, in this embodiment, each of the plurality of first elastic members 151 is elastically deformed in accordance with the posture of the electrode 110 when it comes into contact with the article 2a located on the electrode 110 side. As a result, each of the plurality of first elastic members 151 arranged at a position corresponding to the inclination of the article 2 is elastically deformed in the Y direction, so that the electrode 110 and the base member 120 can be inclined.

[0076] After the articles 2 are bonded, the first bonding unit 10 is driven in the Y direction away from the articles 2. At this time, one second elastic member 152 urges the electrode 110 and the base member 120 in the Y direction via the guide member 160. As a result, if the electrode 110 and the base member 120 are inclined in the Y direction in accordance with the inclination of the articles 2, the inclination of the electrode 110 and the base member 120 can be corrected to their original parallel state with respect to the XZ plane.

[0077] In the solid-state resistance spot bonding apparatus 1 according to an embodiment of the present invention, by arranging a plurality of first elastic members 151 around the pressure shaft 100 and biasing the electrode 110, when the articles 2 are placed at an angle, each of the plurality of first elastic members 151 can elastically deform in accordance with the angle of the articles 2. This makes it possible to tilt the electrode 110 with respect to the axial direction (Y direction) of the pressure shaft 100, so that when the articles 2 are placed at an angle, the electrode 110 can be brought into uniform contact with the articles 2. Furthermore, by ensuring a current path between the electrode 110 and the articles 2, a softened region R can be formed uniformly in the articles 2, thereby suppressing the occurrence of poor bonding.

[0078] In a solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, a base member 120 is provided and a plurality of first elastic members 151 are abutted against the flange portion 123 of the base member 120. This allows the plurality of first elastic members 151 to abut over a wider area than when the plurality of first elastic members 151 are abutted directly against the electrode 110, and therefore the electrode 110 can be stably biased by the plurality of first elastic members 151 via the base member 120.

[0079] In the solid-state resistance spot bonding apparatus 1 according to the embodiment of the present invention, by providing the guide member 160, it is possible to prevent the positional deviation of the plurality of first elastic members 151.

[0080] In the solid-state resistance spot bonding apparatus 1 according to an embodiment of the present invention, by biasing the electrode 110 from near the center with one second elastic member 152, when the electrode 110 is separated from the objects 2 after bonding the objects 2, the electrode 110, which has been tilted in accordance with the objects 2, can be corrected from the tilted state to its original state.

[0081] In the solid-state resistance spot bonding apparatus 1 according to one embodiment of the present invention, the contact between the base member 120 and the lid portion 140 is made to be a line contact, thereby reducing the contact resistance of the contacting members, and making it easier to tilt the electrode 110 relative to the workpiece 2.

[0082] A solid-state resistance spot joining apparatus according to a modified example of an embodiment of the present invention will be described below with reference to the drawings. The solid-state resistance spot joining apparatus according to this modified example has a different configuration of the first joining unit from that of solid-state resistance spot joining apparatus 1 according to an embodiment of the present invention, and therefore, the configuration that is the same as that of solid-state resistance spot joining apparatus 1 according to an embodiment of the present invention will not be described repeatedly.

[0083] 7 is a cross-sectional view showing the configuration of a solid-state resistance spot welding apparatus according to a modified example of an embodiment of the present invention. As shown in FIG. 7, the solid-state resistance spot welding apparatus 1A according to this modified example includes a first welding unit 10A, a second welding unit 20, a drive source, and a power supply unit.

[0084] The first bonding unit 10A and the second bonding unit 20 are units for pressing the plurality of articles 3 to be bonded so as to be plastically deformable, and for applying a voltage to the plurality of articles 3 to be bonded.

[0085] The article 3 to be bonded by the solid-state resistance spot bonding apparatus 1A is composed of an article 3a to be bonded having a protrusion C and a flat-plate-shaped article 3b to be bonded.

[0086] The first joining unit 10A in this modification includes a pressing shaft 200 and a base member 220.

[0087] The pressing shaft 200 is longer in the Y direction than the pressing shaft 100 in the second joining unit 20 .

[0088] The base member 220 is longer in the Y direction than the base member 120 in the second joining unit 20. Specifically, the base member 220 has a main body portion 221, a connection end portion 122, and a flange portion 123. The main body portion 221 is longer in the Y direction than the main body portion 121 of the base member 120 in the second joining unit 20.

[0089] The length by which the pressure shaft 200 and the base member 220 in the first joining unit 10A protrude from the plate-like member 170 toward the articles to be joined 3 is longer than the length by which the pressure shaft 100 and the base member 120 protrude from the plate-like member 170 in the second joining unit 20 toward the articles to be joined 3. This allows the pressure shaft 200 and the electrode 110 to be pressed against the articles to be joined 3 without the first joining unit 10A coming into contact with the convex portion C of the articles to be joined 3a, and therefore the articles to be joined 3 can be joined by the solid-state resistance spot joining apparatus 1A.

[0090] The pressure shaft 200 and the base member 220 can be replaced with other pressure shafts and base members of different lengths by removing other components such as the lid portion 140 and the plate-like member 170. This makes it easy to change the length of the first joining unit 10A in the Y direction to suit various workpiece shapes.

[0091] In the solid-state resistance spot welding apparatus 1A according to a modified example of the embodiment of the present invention, the length in the Y direction of the pressure shaft 200 and the base member 220 in the first welding unit 10A is made longer relative to the pressure shaft 100 and the base member 120 of the second welding unit 20 in accordance with the shape of the objects to be welded 3, so that the length of the first welding unit 10A can be changed in accordance with the shape of the objects to be welded 3. This allows the solid-state resistance spot welding apparatus 1A to be configured to accommodate objects to be welded having various shapes.

[0092] In the above-described 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 an indirect method or a series method.

[0093] Furthermore, although the above-described embodiment describes a stationary solid resistance spot welding apparatus, the present invention is not limited to this configuration and can also be applied to a gun-type welding apparatus attached to the tip of a robot or the like.

[0094] 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]

[0095] 1, 1A solid resistance spot bonding apparatus, 2, 2a, 2b, 3, 3a, 3b workpieces, 10, 10A first bonding unit, 30 driving source, 100, 200 pressure shaft, 110 electrode, 120, 220 base member, 122 connection end, 123 flange portion, 125 first recess, 130 case member, 140 lid portion, 141 second recess, 142 sphere, 151 first elastic member, 152 second elastic member, 160 guide member, 161 through hole.

Claims

1. A driving source; a joining unit driven in the axial direction by the drive source, The joining unit is a pressure shaft that presses the stacked objects in the axial direction so as to be plastically deformable; an electrode that is arranged around the pressure shaft with a gap therebetween and applies a voltage to the plurality of objects to be bonded; a plurality of first elastic members arranged around the pressure shaft at intervals and biasing the electrode toward the plurality of objects to be bonded; The driving source drives the joining unit, thereby bringing the electrode into contact with an article to be joined that is located on the electrode side among the plurality of articles to be joined, and pressing the electrode against the plurality of articles to be joined by the biasing forces of the plurality of first elastic members, while pressing the pressure shaft against the plurality of articles to be joined; the electrode is supported so as to be able to change its posture so as to conform to and come into contact with a contact surface of the object to be bonded located on the electrode side, a first elastic member that is in contact with an object to be joined located on the electrode side and that is elastically deformed in accordance with the posture of the electrode when the first elastic member is in contact with the object to be joined located on the electrode side;

2. the joining unit further includes a base member extending in the axial direction with a gap therebetween so as to surround the pressurizing shaft, the base member having a connection end connected to the electrode and a flange portion aligned with the plurality of first elastic members in the axial direction, each of the plurality of first elastic members contacts the flange portion and biases the electrode via the base member; 2. The solid-state resistance spot joining apparatus according to claim 1, wherein a range within which the electrode can be tilted with respect to the axial direction is defined by a gap between the electrode and the base member and the pressure axis.

3. the joining unit further includes a guide member that is disposed around the pressure shaft with a gap therebetween and that supports the plurality of first elastic members; The guide member is provided with a plurality of through holes penetrating in the axial direction, 3. The solid-state resistance spot joining device according to claim 1, wherein a corresponding one of the plurality of first elastic members is inserted into each of the plurality of through holes.

4. 4. The solid-state resistance spot joining device according to claim 3, wherein the joining unit further includes a second elastic member that is arranged inside the plurality of first elastic members around the pressure shaft and that urges the electrode toward the plurality of workpieces via the guide member.

5. The joining unit is a case member that is positioned around the pressurizing shaft, that houses the plurality of first elastic members therein, and that abuts against the plurality of first elastic members from a side opposite to the electrode in the axial direction; a cover portion connected to the end of the case member on the electrode side while facing the flange portion; a sphere disposed between the lid portion and the flange portion, a first recess is provided on the lid side of the flange, a second recess is provided on the flange portion side of the lid portion, The solid resistance spot joining apparatus according to claim 2 , wherein the sphere is capable of making line contact with each of the first recess and the second recess.

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