Solid-phase resistance spot bonding device

Abstract

The pressure applied to the electrodes can be easily changed. [Solution] The solid-phase resistance spot bonding apparatus 1 comprises a pressurizing shaft 100, an electrode 110, and a drive mechanism 120. The drive mechanism 120 is capable of moving the electrode 110 relative to the pressurizing shaft 100 in the axial direction. The drive mechanism 120 includes a cylinder 130 and a piston 140. The cylinder 130 is fixed to the pressurizing shaft 100 so as to surround the pressurizing shaft 100 and has an inner circumferential surface 135 extending along the axial direction. The piston 140 is housed in the cylinder 130 while being connected to the electrode 110 and is driven by fluid pressure. The piston 140 divides the internal space of the cylinder 130 into a first chamber 11 and a second chamber 12. As fluid alternately enters and exits the first chamber 11 and the second chamber 12, the piston 140 is driven axially while sliding against the inner circumferential surface 135, thereby enabling the electrode 110 to move axially together with the piston 140.

Description

Technical Field

[0001] The present invention relates to a solid-phase resistance spot welding apparatus.

Background Art

[0002] As a prior art document that discloses the configuration of a solid-phase resistance spot welding apparatus, there is Japanese Unexamined Patent Application Publication No. 2024-8499 (Patent Document 1). The solid-phase resistance spot welding apparatus described in Patent Document 1 includes a pressing shaft, an electrode, and an elastic member. The pressing shaft presses a plurality of stacked workpieces so as to be plastically deformed. The electrode is disposed around the pressing shaft and applies a voltage to the plurality of workpieces. The elastic member biases the electrode toward the plurality of workpieces.

[0003] As a prior art document that discloses the configuration of a rotary pressing device for rotary friction welding, there is Japanese Unexamined Patent Application Publication No. 2022-74258 (Patent Document 2). The rotary pressing device for rotary friction welding described in Patent Document 2 performs rotary friction welding on a plug and an object. The rotary pressing device for rotary friction welding includes a pressing mechanism. The pressing mechanism applies a pressing force to the plug by a hydraulic cylinder.

[0004] In addition, there is Japanese Patent No. 5204928 (Patent Document 3) as a prior art document that discloses a cylinder configuration similar to that of Patent Document 2.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The solid-phase resistance spot bonding apparatus described in Patent Document 1 requires the elastic member to be replaced each time the electrode pressure is changed to obtain the required pressure. If the electrode pressure is changed frequently, the amount of work required to change the electrode pressure may increase.

[0007] In devices other than the solid-phase resistance spot bonding apparatus described in Patent Documents 2 and 3, a cylinder structure driven by fluid pressure is disclosed. There is potential to apply this cylinder structure to setting the pressure applied to electrodes in a solid-phase resistance spot bonding apparatus.

[0008] The present invention has been made to solve the above problems and aims to provide a solid-phase resistance spot bonding apparatus that can easily change the applied pressure of the electrodes. [Means for solving the problem]

[0009] The solid-phase resistance spot bonding apparatus according to the present invention comprises a pressurizing shaft, electrodes, and a drive mechanism. The pressurizing shaft presses multiple stacked objects to be bonded in an axial direction so as to be plastically deformable. The electrodes are arranged around the pressurizing shaft and apply a voltage to the multiple objects to be bonded. The drive mechanism is capable of moving the electrodes relative to the pressurizing shaft in the axial direction. The drive mechanism includes a cylinder and a piston. The cylinder is fixed to the pressurizing shaft so as to surround it and has an inner circumferential surface extending along the axial direction. The piston is housed in the cylinder while being connected to the electrodes and is driven by fluid pressure. The piston divides the internal space of the cylinder into a first chamber and a second chamber. As fluid alternately enters and exits the first and second chambers, the piston is driven in the axial direction while sliding against the inner circumferential surface, thereby enabling the electrodes to move in the axial direction together with the piston.

[0010] In this case, compared to the case where the electrodes are driven by an elastic member, it is not necessary to replace the elastic member each time the pressure applied to the electrodes is changed, thus reducing the amount of work required to change the pressure applied to the electrodes. As a result, the solid-phase resistance spot bonding device can easily change the pressure applied to the electrodes.

[0011] In one embodiment of the present invention, each of the cylinder and the piston has an insulating portion such that the pressurizing shaft and the electrode are insulated from each other.

[0012] This allows for insulation between the pressurizing shaft and the electrode, thereby suppressing the adhesion between the pressurizing shaft and multiple objects to be joined when voltage is applied to the pressurizing shaft.

[0013] In one embodiment of the present invention, the piston has a rod portion and a flange portion. The rod portion extends in the axial direction, and one end in the axial direction is connected to an electrode. The flange portion extends radially from the other end of the rod portion in the axial direction in a direction perpendicular to the axial direction and abuts against the inner circumferential surface. The first chamber is located on the rod portion side when viewed from the flange portion. The second chamber is located on the opposite side from the rod portion when viewed from the flange portion. The rod portion and the flange portion are provided with holes that penetrate in the axial direction. The holes are sealed when inserted through the pressurizing shaft. The second chamber is surrounded by a cylinder, the flange portion and the pressurizing shaft.

[0014] In this case, by using a single-rod drive mechanism, a portion of the second chamber can be enclosed by the pressure shaft compared to a double-rod mechanism, thus eliminating the need to omit part of the cylinder's configuration. As a result, the drive mechanism can be miniaturized, and therefore the solid-phase resistance spot bonding device can be miniaturized.

[0015] In one embodiment of the present invention, the cylinder has a metal bush that forms the inner circumferential surface and slides with the piston.

[0016] This improves the durability of the drive mechanism.

[0017] In one embodiment of the present invention, the solid-phase resistance spot welding apparatus further includes a sleeve. The sleeve is disposed so as to close the gap between the pressure shaft and the electrode and has insulating properties. The sleeve is slidable with respect to the pressure shaft or the electrode.

[0018] Thereby, it is possible to suppress sputtering during solid-phase resistance spot welding from entering the inside of the drive mechanism, so that the drive mechanism can be stably driven.

Advantages of the Invention

[0019] According to the present invention, the pressing force of the electrode can be easily changed.

Brief Description of the Drawings

[0020] [Figure 1] It is a front view showing the configuration of a solid-phase resistance spot welding apparatus according to an embodiment of the present invention. [Figure 2] It is a perspective view showing the configuration of a joining unit according to an embodiment of the present invention. [Figure 3] It is a cross-sectional view of the configuration of the joining unit of FIG. 2 as viewed from the direction of the arrow III-III. [Figure 4] It is a cross-sectional view showing a state where the electrode is pushed out toward the workpiece by the drive mechanism. [Figure 5] It is a cross-sectional view showing the configuration of a drive mechanism included in a solid-phase resistance spot welding apparatus according to a comparative example.

Embodiments for Carrying Out the Invention

[0023] Figure 1 is a front view showing the configuration of a solid-phase resistance spot bonding apparatus according to one embodiment of the present invention.

[0024] As shown in Figure 1, the solid-phase resistance spot bonding apparatus 1 according to one embodiment of the present invention is an apparatus that bonds multiple objects to be bonded together while remaining in a solid state by applying an electric current to multiple objects to be bonded 2, thereby forming softened regions in the objects to be bonded 2, and then plastically deforming these softened regions.

[0025] The solid-phase resistance spot bonding apparatus 1 comprises a bonding unit 10 and other bonding units 20.

[0026] The joining unit 10 is a unit for pressing multiple objects to be joined 2 in a way that allows for plastic deformation, and for applying voltage to the multiple objects to be joined 2. The joining unit 10 is driven axially (Y direction) by a drive source such as a servo press (not shown). The configuration of the joining unit 10 will be described later.

[0027] The other bonding unit 20 is a unit that presses multiple objects to be bonded 2 together with the bonding unit 10 and applies a voltage to the multiple objects to be bonded 2. The other bonding unit 20 is fixed to a housing (not shown) of the solid-phase resistance spot bonding apparatus 1.

[0028] In this embodiment, the other joining unit 20 has the same configuration as the joining unit 10, but is symmetrical with respect to the joining unit 10 with respect to the XZ plane. However, the other joining unit 20 is not limited to this configuration, and may, for example, have a configuration in which the drive mechanism 120 described later is not provided.

[0029] Voltage is applied to the junction unit 10 and the other junction units 20 from a power supply unit (not shown). Voltage is applied to the junction unit 10 from a connecting conductor 150, which will be described later. Voltage is also applied to the other junction units 20 from connecting conductors.

[0030] The objects to be joined 2 by the solid-phase resistance spot bonding apparatus 1 are, for example, steel plates such as high-tensile steel. However, the objects to be joined 2 are not limited to steel plates; they may also be aluminum plates or dissimilar materials such as steel plates and aluminum plates.

[0031] The joining unit 10 will now be described. Figure 2 is a perspective view showing the configuration of a joining unit according to one embodiment of the present invention. Figure 3 is a cross-sectional view of the configuration of the joining unit in Figure 2, taken from the direction of the arrow III-III.

[0032] As shown in Figures 2 and 3, the joining unit 10 in one embodiment of the present invention includes a pressurizing shaft 100, an electrode 110, a drive mechanism 120, a connecting conductor 150, a plate-shaped member 151, a wiring member 152, and a sleeve 160.

[0033] The pressurizing shaft 100 presses the multiple stacked objects 2 in an axial direction (Y direction) in a way that allows for plastic deformation. Specifically, in this embodiment, the pressurizing shaft 100 presses the multiple objects 2 with a pressing force of 30 to 50 kN when driven by a drive source.

[0034] In this embodiment, the pressurizing shaft 100 has a main shaft 101 and a tubular member 103. Alternatively, the pressurizing shaft 100 may have a configuration in which the main shaft 101 and the tubular member 103 are integrated.

[0035] The main shaft 101 is a cylindrical member extending in the Y direction. The material of the main shaft 101 is, for example, tungsten carbide. However, the material of the main shaft 101 is not particularly limited as long as it can apply the necessary pressing force to the workpiece 2, and may be tool steel, heat-resistant steel, or ceramics, etc.

[0036] The main shaft 101 has a tip 105 and a rear end 106. The tip 105 is the part that contacts the workpiece 2A (see Figure 1) located on the joining unit 10 side among the multiple workpieces 2. The rear end 106 is connected to the tubular member 103. The rear end 106 has a tapered shape and engages with the inner circumferential surface of the tubular member 103.

[0037] In this embodiment, the spindle 101 is composed of two interchangeable tip components. However, the spindle 101 is not limited to this configuration and may be composed of a single component.

[0038] The tubular member 103 is a member that supports the main shaft 101. The material of the tubular member 103 is, for example, steel.

[0039] The tubular member 103 has a cylindrical portion 107 and a flange portion 108. The cylindrical portion 107 extends in the Y direction. The cylindrical portion 107 has a tapered inner circumferential surface at its tip. The flange portion 108 extends radially from the upper end of the cylindrical portion 107 in the XZ plane. The flange portion 108 is fixed to the connecting conductor 150.

[0040] The electrode 110 is driven in the Y direction by a drive source together with the pressurizing shaft 100. The electrode 110 is positioned around the pressurizing shaft 100 with a gap between it and the shaft. In this embodiment, the tip 111 of the electrode 110 has a cylindrical shape when viewed from the Y direction.

[0041] The electrode 110 applies a voltage to multiple objects 2. By applying a voltage to the multiple objects 2, the electrode 110 heats the multiple objects 2 by passing a current of 3500 to 10000 A through them. The electrode 110 is made of, for example, copper.

[0042] In this embodiment, the electrode 110 is composed of two interchangeable tip portions. However, the electrode 110 is not limited to this configuration and may be composed of a single portion.

[0043] The connecting conductor 150 is fixed to the tubular member 103 in an insulated state. The plate-shaped member 151 is conductive and connected to the circumferential surface of the electrode 110. The wiring member 152 electrically connects the connecting conductor 150 and the plate-shaped member 151. The wiring member 152 is made of, for example, copper wire.

[0044] The current supplied from the power supply flows through the connecting conductor 150, wiring member 152, plate-shaped member 151, and electrode 110 in that order, and then flows to the object to be joined 2. In the solid-phase resistance spot bonding apparatus 1, the pressure applied by the pressurizing shaft 100 and electrode 110 to the object to be joined 2 causes the objects to be joined 2A and 2B to come into close contact at their contact surfaces, thereby reducing the contact resistance. As a result, the contact surface with reduced contact resistance becomes a current-carrying path, and current flows through this current-carrying path.

[0045] The drive mechanism 120 is capable of moving the electrode 110 relative to the pressurizing shaft 100 in the axial direction (Y direction). The drive mechanism 120 is driven by fluid pressure. In this embodiment, the drive mechanism 120 is driven by air pressure. However, the drive mechanism 120 is not limited to an air-driven system, and may be driven by the pressure of other fluids such as hydraulics.

[0046] The drive mechanism 120 includes a cylinder 130 and a piston 140.

[0047] The cylinder 130 is fixed to the pressurizing shaft 100 so as to surround it. The cylinder 130 surrounds the entire circumference of the pressurizing shaft 100 in the Y direction. The cylinder 130 is fixed to the pressurizing shaft 100, for example, by bolt fastening. The cylinder 130 is fixed to the flange portion 108 of the tubular member 103 of the pressurizing shaft 100.

[0048] The cylinder 130 includes a cylinder head 131, a bush 132, and a cylinder rod 133.

[0049] The cylinder head 131 is a plate-shaped member extending in the XZ plane. The cylinder head 131 abuts against the flange portion 108 of the tubular member 103 from the Y direction. The cylinder head 131 is provided with a hole 134 that penetrates in the Y direction. The tubular member 103 of the pressurizing shaft 100 is inserted through the hole 134 in the cylinder head 131.

[0050] The bush 132 is located on the electrode 110 side of the cylinder head 131. The bush 132 is sandwiched between the cylinder head 131 and the cylinder rod 133.

[0051] The bush 132 is a cylindrical member extending along the axial direction (Y direction). The bush 132 has an inner circumferential surface 135 extending along the axial direction (Y direction). That is, the bush 132 constitutes the inner circumferential surface 135 of the cylinder 130. The bush 132 is made of metal. The bush 132 slides against the piston 140.

[0052] The cylinder rod 133 is a plate-shaped member extending in the XZ plane. The cylinder rod 133 is positioned on the electrode 110 side of the bush 132. The cylinder rod 133 is provided with a hole 136 that penetrates in the Y direction. The pressurizing shaft 100 and the piston 140 are inserted through the hole 136 in the cylinder rod 133.

[0053] An inner bush 137 is provided in the hole 136 of the cylinder rod 133. The inner bush 137 is made of metal. The inner bush 137 slides against the rod portion 141 of the piston 140, which will be described later.

[0054] The piston 140 is housed in the cylinder 130 and connected to the electrode 110. The piston 140 is driven by fluid pressure. In this embodiment, the piston 140 is driven by air pressure.

[0055] The piston 140 has a rod portion 141 and a flange portion 142. The drive mechanism 120 in this embodiment has a so-called single-rod structure in which one rod portion 141 is provided on one side of the flange portion 142.

[0056] The rod portion 141 has a cylindrical shape. The rod portion 141 extends in the axial direction (Y direction). One end of the rod portion 141 in the axial direction (Y direction) is connected to the electrode 110. The rod portion 141 is connected to the electrode 110 by screwing it in.

[0057] The flange portion 142 extends radially from the other end of the rod portion 141 in the axial direction (Y direction) in a direction perpendicular to the axial direction. In this embodiment, the flange portion 142 extends radially on the XZ plane. The flange portion 142 is in contact with the inner circumferential surface 135.

[0058] The rod portion 141 and the flange portion 142 are provided with holes 143 that penetrate axially (in the Y direction). The pressurizing shaft 100 is inserted through the holes 143. The piston 140 is positioned to be supported by the outer circumferential surface 109 of the pressurizing shaft 100. The holes 143 are sealed while the pressurizing shaft 100 is inserted through them.

[0059] Each of the cylinder 130 and piston 140 has an insulating portion so as to insulate the pressurizing shaft 100 from the electrode 110. In this embodiment, each of the cylinder 130 and piston 140 has an insulating portion by being made of an insulating material. Each of the cylinder 130 and piston 140 is made of, for example, phenolic resin. Alternatively, each of the cylinder 130 and piston 140 may be made of metal coated with an insulating material.

[0060] The drive mechanism 120 is provided with an inner packing 121, an outer packing 122, a ring member 123, an upper packing 124, and a lower packing 125.

[0061] The inner packing 121 is provided on the wall surface of the hole 143. The inner packing 121 is provided to seal the hole 143 when it is inserted through the pressure shaft 100.

[0062] The inner packing 121 is provided in at least two locations along the axial direction (Y direction). In this embodiment, two inner packings 121 are provided along the axial direction (Y direction) with a gap between them. This supports the piston 140 in a direction along the Y direction with respect to the pressurizing shaft 100. As a result, tilting of the piston 140 in the Y direction or misalignment of the piston 140 with respect to the pressurizing shaft 100 can be suppressed.

[0063] The outer packing 122 and the ring member 123 are provided on the outer circumference of the flange portion 142. The outer packing 122 seals the space between the inner circumferential surface 135 of the cylinder 130 and the flange portion 142 of the piston 140. The ring member 123 assists in the sliding between the inner circumferential surface 135 and the flange portion 142. The ring member 123 is made of metal or resin. If the ring member is made of resin, it is desirable that the resin be relatively strong, such as cloth-reinforced phenol. As a result, the resin ring member is more resistant to seizing or galling during sliding compared to the metal ring member.

[0064] The upper packing 124 is provided on the cylinder head 131. The upper packing 124 seals the space between the pressurizing shaft 100 and the drive mechanism 120.

[0065] The upper packing 124 is provided on the upper end surface in the Y direction of the cylinder head 131. If the upper packing 124 were to be placed on the wall surface of the hole 134 provided in the cylinder head 131, in order to ensure the sealing function of the upper packing 124, the sealing function of the inner packing 121 may become insufficient due to the relationship between the manufacturing tolerances of the upper packing 124 and the inner packing 121. Therefore, by providing the upper packing 124 on the upper end surface in the Y direction of the cylinder head 131, the upper packing 124 and the inner packing 121 are not arranged along the outer circumferential surface 109. As a result, the influence of the upper packing 124 on the sealing function of the inner packing 121 is suppressed, and the airtightness of the internal space of the drive mechanism 120 can be improved.

[0066] The lower packing 125 is provided on the wall surface of the hole 136 of the cylinder rod 133. The lower packing 125 seals the space between the rod portion 141 and the cylinder rod 133.

[0067] The internal space of the cylinder 130 is sealed by an inner packing 121, an upper packing 124, and a lower packing 125.

[0068] The piston 140 divides the internal space of the cylinder 130 into a first chamber 11 and a second chamber 12. The first chamber 11 is located on the rod portion 141 side when viewed from the flange portion 142. The second chamber 12 is located on the opposite side from the rod portion 141 when viewed from the flange portion 142.

[0069] The first chamber 11 is in communication with the first supply path 15. The first supply path 15 is provided so as to pass through the inside of the cylinder rod 133. Air can be supplied to the first chamber 11 from the first supply path 15. In addition, the air in the first chamber 11 can be exhausted from the first supply path 15.

[0070] The second chamber 12 is in communication with the second supply path 16. The second supply path 16 is provided to pass through the inside of the cylinder head 131. Air can be supplied to the second chamber 12 from the second supply path 16. In addition, the air in the second chamber 12 can be exhausted from the second supply path 16.

[0071] The sleeve 160 is positioned to close the gap between the pressurizing shaft 100 and the electrode 110. The sleeve 160 is insulating.

[0072] The sleeve 160 is slidable with respect to the pressure shaft 100 or the electrode 110. In this embodiment, the sleeve 160 is fitted onto the pressure shaft 100. This allows the sleeve 160 to slide with respect to the electrode 110.

[0073] Figure 4 is a cross-sectional view showing the state in which the electrode is pushed towards the workpiece by the drive mechanism.

[0074] As shown in Figures 3 and 4, the piston 140 is driven axially (in the Y direction) as fluid alternately enters and exits the first chamber 11 and the second chamber 12, sliding against the inner circumferential surface 135. This allows the electrode 110 to move axially (in the Y direction) together with the piston 140.

[0075] As shown in Figures 1, 3, and 4, the operation of the solid-phase resistance spot bonding apparatus 1 begins with the drive mechanism 120 moving the electrodes 110 toward the multiple objects to be bonded 2. Specifically, the air in the first chamber 11 of the cylinder 130 is exhausted, and air is supplied to the second chamber 12. The first chamber 11 narrows, and the second chamber widens. As a result, the electrodes 110 move toward the objects to be bonded 2 as the piston 140 is driven (in the DR1 direction in Figure 4). The maximum travel distance of the electrodes 110 is, for example, 8 mm.

[0076] Next, the drive source drives the joining unit 10, causing the electrode 110 to come into contact with the object 2A located on the joining unit 10 side of the multiple objects 2 to be joined. By bringing the electrode 110 into contact with the object 2A before the pressurizing shaft 100 and applying prepressure, the objects 2 to be joined can be temporarily positioned. In addition, the electrodes of the other joining unit 20 come into contact with the object 2B of the multiple objects 2 to be joined.

[0077] Next, the pressure applied by the drive mechanism 120 presses the electrodes 110 against the multiple objects to be joined 2, while simultaneously pressing the pressurizing shaft 100 against the multiple objects to be joined 2. The electrodes 110 retract under air pressure until the pressurizing shaft 100 comes into contact with the multiple objects to be joined 2.

[0078] Next, a voltage is applied from the electrode 110 to the multiple objects to be joined 2. The contact surfaces where the objects to be joined 2 are in close contact and have low contact resistance become current-carrying paths, and current flows through these paths. As a result, the multiple objects to be joined 2 are heated, and softened regions are formed between the multiple objects to be joined 2.

[0079] As current is passed through the electrode 110 to the object to be joined 2, and it is pressed by the pressure shaft 100, the softened region of the object to be joined 2 undergoes plastic deformation. This plastic deformation of the softened region creates a new surface in the softened region. When these new surfaces come into contact with each other, the objects to be joined 2A and 2B are solid-phase resistance spot bonded together.

[0080] The order in which the pressurizing shaft 100 and the electrode 110 contact the object to be joined 2 is not limited. The pressurizing shaft 100 may contact the object to be joined 2 before the electrode 110, or the pressurizing shaft 100 and the electrode 110 may contact the object to be joined 2 simultaneously.

[0081] The following describes a solid-phase resistance spot bonding apparatus according to a comparative example. Since the configuration of the drive mechanism of the solid-phase resistance spot bonding apparatus according to the comparative example differs from that of the solid-phase resistance spot bonding apparatus 1 according to one embodiment of the present invention, the same configuration as that of the solid-phase resistance spot bonding apparatus 1 according to one embodiment of the present invention will not be repeated in the description.

[0082] Figure 5 is a cross-sectional view showing the configuration of the drive mechanism of a solid-phase resistance spot bonding apparatus according to a comparative example. Note that detailed connection structures of each component are omitted in Figure 5.

[0083] As shown in Figure 5, the solid-phase resistance spot bonding apparatus 1A according to the comparative example comprises a pressurizing shaft 200, an electrode 210, and a drive mechanism 220. The drive mechanism 220 includes a cylinder 230 and a piston 240. The cylinder 230 has a cylinder head 231, a bush 232, and a cylinder rod 233.

[0084] The piston 240 in the comparative example has a first rod portion 241, a flange portion 242, and a second rod portion 244. The drive mechanism 220 in this comparative example has a so-called double-rod structure in which rod portions are provided on both sides of the flange portion 242.

[0085] In the comparative example, the second chamber 22 is partitioned by the cylinder 230 and the piston 240. The alignment of the cylinder head 231 and the second rod portion 244 on the XZ plane tends to result in a relatively large size for the drive mechanism 220 on the XZ plane.

[0086] On the other hand, as shown in Figures 3 and 4, the drive mechanism 120 of one embodiment is a so-called single-rod structure. Therefore, the second chamber 12 is surrounded by the cylinder 130, the flange portion 142, and the pressurizing shaft 100. Compared to the drive mechanism 220 with a double-rod structure in the comparative example, the drive mechanism 120 in one embodiment can be made smaller because, by surrounding a part of the second chamber 12 with the pressurizing shaft 100, a part of the cylinder 130's configuration (the second rod portion 244 in this comparative example) can be omitted.

[0087] In the solid-phase resistance spot bonding apparatus 1 of this embodiment, the electrode 110 is moved by a drive mechanism 120 that uses the pressure of a fluid (air in this embodiment). This allows the required pressure applied to the electrode 110 to be changed by adjusting the fluid pressure. Compared to the case in which the electrode 110 is driven by an elastic member, the solid-phase resistance spot bonding apparatus 1 eliminates the need to replace the elastic member each time the pressure applied to the electrode 110 is changed, thus reducing the amount of work required to change the pressure applied to the electrode 110. As a result, the solid-phase resistance spot bonding apparatus 1 allows for easy changes to the pressure applied to the electrode 110.

[0088] In the solid-phase resistance spot bonding apparatus 1 of this embodiment, since each of the cylinder 130 and piston 140 has an insulating portion, the pressure shaft 100 and the electrode 110 can be insulated, and thus the adhesion between the pressure shaft 100 and the multiple objects to be bonded 2 that occurs when voltage is applied to the pressure shaft 100 can be suppressed.

[0089] When the drive mechanism 120 is constructed from insulating material, it is conceivable that the insulating material may be made of a material with lower rigidity than metal, such as resin. In this case, the drive mechanism 120 tends to become larger in order to ensure sufficient rigidity. In this embodiment, the pressurizing shaft 100 supports the piston 140 of the drive mechanism 120. As a result, the pressurizing shaft 100 and the piston 140 can be considered as a single unit, and the rigidity of the piston 140 can be ensured. Therefore, the piston 140 can be made smaller compared to the size required to ensure rigidity of the piston 140 alone. Consequently, the drive mechanism 120 can be miniaturized.

[0090] In the solid-phase resistance spot bonding apparatus 1 of this embodiment, by making the drive mechanism 120 a single-rod mechanism, compared to the case where the fluid containment chamber is defined only by the cylinder and piston (double-rod mechanism), a part of the second chamber 12 of the air containment chambers, the first chamber 11 and the second chamber 12, can be enclosed by the pressurizing shaft 100, thus allowing a part of the cylinder 130's configuration to be omitted. As a result, the drive mechanism 120 can be made smaller. Consequently, the solid-phase resistance spot bonding apparatus 1 can be made smaller.

[0091] In the solid-phase resistance spot bonding apparatus 1 of this embodiment, the cylinder 130 has a metal bush 132 that slides against the piston 140, so that the metal bush 132 can be placed at the sliding point of the piston 140 to improve the durability of the drive mechanism 120.

[0092] In the solid-phase resistance spot bonding apparatus 1 of this embodiment, by closing the gap between the pressurizing shaft 100 and the electrode 110 and providing a sliding sleeve 160 on the electrode 110, it is possible to suppress sputter during solid-phase resistance spot bonding from entering the inside of the drive mechanism 120, thereby enabling stable driving of the drive mechanism 120. Furthermore, since the electrode 110 is positioned by the sleeve 160, misalignment of the electrode 110 with respect to the pressurizing shaft 100 can be suppressed.

[0093] [Note] As described above, this embodiment includes the following disclosures.

[0094] [Configuration 1] A pressing shaft (100) presses multiple overlapping objects (2) in an axial direction in a way that allows for plastic deformation, An electrode (110) is arranged around the pressurizing shaft (100) and applies voltage to the plurality of objects to be joined (2), The system includes a drive mechanism (120) that allows the electrode (110) to move relative to the pressurizing shaft (100) in the axial direction, The aforementioned drive mechanism (120) is A cylinder (130) is fixed to the pressurizing shaft (100) so as to surround the pressurizing shaft (100) and has an inner circumferential surface (135) extending along the axial direction, It includes a piston (140) that is connected to the electrode (110) and housed in the cylinder (130), and is driven by the pressure of a fluid, The piston (140) divides the internal space of the cylinder (130) into a first chamber (11) and a second chamber (12). A solid-phase resistance spot bonding apparatus (1) is configured such that the fluid alternately enters and exits the first chamber (11) and the second chamber (12), causing the piston (140) to slide against the inner circumferential surface (135) and be driven in the axial direction, thereby enabling the electrode (110) to move in the axial direction together with the piston (140).

[0095] [Configuration 2] The solid-phase resistance spot bonding apparatus (1) according to configuration 1, wherein each of the cylinder (130) and the piston (140) has an insulating portion such that the pressurizing shaft (100) and the electrode (110) are insulated.

[0096] [Configuration 3] The aforementioned piston (140) is A rod portion (141) extending in the axial direction, with one end in the axial direction connected to the electrode (110), The rod portion (141) has a flange portion (142) that extends radially from the other end in the axial direction in a direction perpendicular to the axial direction and abuts against the inner circumferential surface (135), The first chamber (11) is located on the rod portion (141) side when viewed from the flange portion (142), The second chamber (12) is located on the opposite side from the rod portion (141) when viewed from the flange portion (142), The rod portion (141) and the flange portion (142) are provided with holes (143) that penetrate in the axial direction. The hole (143) is sealed while inserted through the pressure shaft (100). The solid-phase resistance spot bonding apparatus (1) according to configuration 1 or configuration 2, wherein the second chamber (12) is surrounded by the cylinder (130), the flange portion (142), and the pressure shaft (100).

[0097] [Structure 4] The cylinder (130) has a metal bush (132) that constitutes the inner circumferential surface (135) and slides with the piston (140), as described in any one of configurations 1 to 3, for the solid phase resistance spot bonding device (1).

[0098] [Composition 5] The system further includes an insulating sleeve (160) that is positioned to close the gap between the pressurizing shaft (100) and the electrode (110), The sleeve (160) is slidable with respect to the pressure shaft (100) or the electrode (110), as described in any one of configurations 1 to 4, of the solid-phase resistance spot bonding apparatus (1).

[0099] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not limited to the embodiments described above. Furthermore, all modifications within the meaning and scope of equivalence to the claims are included. In the description of the embodiments above, combinatorial configurations may be combined with each other. [Explanation of Symbols]

[0100] 1,1A Solid phase resistance spot bonding device, 2 Multiple objects to be bonded, 2A,2B Objects to be bonded, 11 First chamber, 12,22 Second chamber, 100,200 Pressurizing shaft, 110,210 Electrode, 120,220 Drive mechanism, 130,230 Cylinder, 132,232 Bushing, 135 Inner surface, 140,240 Piston, 141 Rod section, 142,242 Flange section, 143 Hole, 160 Sleeve.

Claims

1. A pressurizing shaft that presses multiple overlapping objects to be joined in an axial direction in a way that allows for plastic deformation, Electrodes arranged around the pressurizing shaft for applying voltage to the plurality of objects to be joined, The system includes a drive mechanism that allows the electrode to move relative to the pressurizing shaft in the axial direction, The aforementioned drive mechanism is A cylinder fixed to the pressurizing shaft so as to surround the pressurizing shaft and having an inner circumferential surface extending along the axial direction, It includes a piston that is housed in the cylinder and connected to the electrode, and is driven by the pressure of a fluid, The piston divides the internal space of the cylinder into a first chamber and a second chamber. A solid-phase resistance spot bonding apparatus in which the fluid alternately enters and exits the first and second chambers, thereby driving the piston in the axial direction while sliding against the inner circumferential surface, and the electrode is movable in the axial direction together with the piston.

2. The solid-phase resistance spot bonding apparatus according to claim 1, wherein each of the cylinder and the piston has an insulating portion such that the pressurizing shaft and the electrode are insulated from each other.

3. The aforementioned piston is A rod portion extending in the axial direction, with one end in the axial direction connected to the electrode, The rod portion has a flange portion that extends radially from the other end in the axial direction in a direction perpendicular to the axial direction and abuts against the inner circumferential surface, The first chamber is located on the rod side when viewed from the flange portion, The second chamber is located on the opposite side from the rod portion when viewed from the flange portion. The rod portion and the flange portion are provided with holes that penetrate in the axial direction. The aforementioned hole is sealed while inserted through the pressure shaft. The solid-phase resistance spot bonding apparatus according to claim 1 or claim 2, wherein the second chamber is surrounded by the cylinder, the flange portion, and the pressure shaft.

4. The solid-phase resistance spot bonding apparatus according to claim 1 or claim 2, wherein the cylinder has a metal bush that constitutes the inner circumferential surface and slides with the piston.

5. The system further comprises an insulating sleeve positioned to close the gap between the pressurizing shaft and the electrode, The solid-phase resistance spot bonding apparatus according to claim 1 or claim 2, wherein the sleeve is slidable with respect to the pressure shaft or the electrode.

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