Welding device and welding method

Abstract

A welding device according to the present invention comprises an electroconductive heat generation body that is to be provided between a resin-containing first welding surface of a first adherend and a resin-containing second welding surface of a second adherend, an electrode that is attached to the heat generation body, a power supply device that applies voltage to the electrode to pass current through the heat generation body, a pressure application device that is to apply pressure to at least one of the first adherend and the second adherend in the direction of the other of the first adherend and the second adherend when current is passing through the heat generation body to cause the heat generation body to generate heat, thereby causing the first welding surface and the second welding surface to be welded together via the heat generation body, and a restriction jig that is to be provided at the first welding surface and the second welding surface so as to be adjacent to the first welding surface and the second welding surface in two directions that are the energization direction of the heat generation body and an orthogonal direction that is orthogonal to the energization direction of the heat generation body.

Description

Welding device and welding method

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2024-027519, filed on February 27, 2024, the contents of which are incorporated herein by reference.

[0002] For example, Patent Document 1 discloses a method for fusing (welding) a pair of joining members by disposing a resistance heating element between the pair of joining members and passing electricity through the resistance heating element while applying pressure to the joining members. In Patent Document 1, the heat generated by the resistance heating element melts the resin on the surface of each joining member, thereby joining the joining members together via the resistance heating element.

[0003] Patent No. 6358818

[0004] In resistance welding such as that described in Patent Document 1, the application of pressure to the joining members during welding can cause some of the molten resin to leak out from the welded portion of the joining members. After welding is complete, the leaked resin solidifies and becomes burrs. In resistance welding, the amount of burrs generated can affect the quality of the weld.

[0005] An object of the present disclosure is to provide a welding apparatus and a welding method that can stabilize the quality of welding.

[0006] In order to solve the above problem, a welding apparatus according to one embodiment of the present disclosure includes a conductive heating element disposed between a first welding surface of a first adherend that includes a resin and a second welding surface of a second adherend that includes a resin, electrodes attached to the heating element, a power supply that applies a voltage to the electrodes to pass a current through the heating element, a pressure device that applies pressure to at least one of the first adherend and the second adherend in a direction in which the first adherend and the second adherend approach each other when the heating element is heated by the current flowing through the heating element, thereby welding the first welding surface and the second welding surface via the heating element, and a restraining jig disposed adjacent to the first welding surface and the second welding surface in two directions: the direction in which current flows through the heating element and a perpendicular direction perpendicular to the direction in which current flows through the heating element.

[0007] In addition, the regulating jig is divided into a first part arranged in the direction of current flow relative to the first welding surface and the second welding surface, and a second part arranged in a direction perpendicular to the first welding surface and the second welding surface, and the thermal conductivity of the material constituting the first part may be different from the thermal conductivity of the material constituting the second part.

[0008] In order to solve the above problem, a welding method according to one aspect of the present disclosure includes the steps of: placing a conductive heating element between a first welding surface of a first adherend, the first welding surface including a resin, and a second welding surface of a second adherend, the second welding surface including a resin; passing a current through the heating element by applying a voltage to electrodes attached to the heating element; applying pressure to at least one of the first adherend and the second adherend in a direction in which the first adherend and the second adherend approach each other, in a state in which the heating element is heated after the step of passing a current through the heating element; and, prior to the steps of passing a current through the heating element and welding the first welding surface and the second welding surface, placing restraining jigs adjacent to the first welding surface and the second welding surface in two directions, the direction in which current flows through the heating element and a direction perpendicular to the direction in which current flows through the heating element.

[0009] In addition, the regulating jig is divided into a first part arranged in the direction of current flow relative to the first welding surface and the second welding surface, and a second part arranged in a direction perpendicular to the first welding surface and the second welding surface, and the thermal conductivity of the material constituting the first part may be different from the thermal conductivity of the material constituting the second part.

[0010] In addition, the amount of clearance between the first and second welding surfaces and the regulating jig may be set based on at least one of an estimated value of the strength of the first and second adherends after welding, the thermal conductivity of the components that make up the regulating jig, and an estimated value of the temperature distribution on the first and second welding surfaces.

[0011] The magnitude of the force for fixing the regulating jig may be set based on the allowable amount of resin that flows out from the first welding surface and the second welding surface.

[0012] According to the present disclosure, it is possible to stabilize the quality of welding.

[0013] FIG. 1 is a schematic diagram showing an example of the configuration of a welding apparatus according to this embodiment. FIG. 2 is a partially enlarged perspective view of the welding apparatus according to this embodiment, seen from an oblique angle. FIG. 3 is a partially enlarged perspective plan view of the welding apparatus according to this embodiment, seen from above. FIG. 4 is a schematic partial cross-sectional view of the welding apparatus according to this embodiment, taken along the current flow direction in FIG. 1. FIG. 5 is a schematic partial cross-sectional view of the welding apparatus according to this embodiment, taken along a direction perpendicular to FIG. 1. FIG. 6 is a flowchart illustrating the flow of a welding method using the welding apparatus according to this embodiment. FIG. 7 is a flowchart illustrating the flow of setting each member. FIG. 8 is a perspective view illustrating the flow of setting each member. FIG. 9 is a perspective view illustrating the flow of setting each member. FIG. 10 is a perspective view illustrating the flow of setting each member. FIG. 11 is a perspective view illustrating the flow of setting each member. FIG. 12 is a perspective view illustrating the flow of setting each member. FIG. 13 is a perspective view illustrating the flow of setting each member. FIG. 14 is a perspective view illustrating the flow of setting each member. FIG. 15 is a perspective view illustrating the flow of setting each member.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0015] FIG. 1 is a schematic diagram showing an example of the configuration of a welding device 1 according to this embodiment. FIG. 2 is a partially enlarged perspective view of the welding device 1 according to this embodiment, seen from an oblique angle. FIG. 3 is a partially enlarged perspective plan view of the welding device 1 according to this embodiment, seen from above. FIG. 4 is a schematic partial cross-sectional view of the welding device 1 according to this embodiment, taken along the current flow direction in FIG. 1. FIG. 5 is a schematic partial cross-sectional view of the welding device 1 according to this embodiment, taken along a direction perpendicular to FIG. 1. The welding device 1 according to this embodiment will be described below, but this embodiment can also be applied to a welding method using the welding device 1.

[0016] The welding apparatus 1 of this embodiment comprises a first adherend 10, a second adherend 12, a heating element 14, a positive electrode 20a, a negative electrode 20b, a power supply unit 22, a pressure unit 24, a control unit 30, a regulating jig 32, a cover jig 34, a work table 40, a pressure jig 42, and a pressure auxiliary jig 44.

[0017] The first adherend 10 and the second adherend 12 are members to be welded to each other by the welding apparatus 1. The first adherend 10 has a first welding surface 60, which is the surface to be welded (see FIGS. 4 and 5). At least the first welding surface 60 of the first adherend 10 is made of a thermoplastic resin. The second adherend 12 has a second welding surface 62, which is the surface to be welded (see FIGS. 4 and 5). At least the second welding surface 62 of the second adherend 12 is made of a thermoplastic resin. Hereinafter, the first welding surface 60 and the second welding surface 62 may be collectively referred to simply as the welding surfaces.

[0018] For example, the first adherend 10 and the second adherend 12 may be made of a fiber-reinforced resin such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP). The first adherend 10 and the second adherend 12 are not limited to fiber-reinforced plastic, and may be made of any composite material or simply a thermoplastic resin. The materials of the first adherend 10 and the second adherend 12 may be the same or different.

[0019] The first adherend 10 and the second adherend 12 may be, for example, flat plates or angle plates with planar welding surfaces. The first adherend 10 and the second adherend 12 may also be curved plates with curved welding surfaces. The first adherend 10 and the second adherend 12 are not limited to the shapes shown as examples, and may be any shape that has at least a welding surface.

[0020] The heating element 14 is made of a conductive material. For example, the heating element 14 may be made of a fiber-reinforced resin such as carbon fiber reinforced plastic (CFRP). More specifically, the heating element 14 may be made of a carbon fiber reinforced resin prepreg in which carbon fibers are arranged in one direction. The heating element 14 may also be made of metal wire such as wire mesh.

[0021] The heating element 14 is formed in a sheet shape. The length of the heating element 14 in at least one direction is longer than the first welding surface 60 of the first adherend 10 and the second welding surface 62 of the second adherend 12.

[0022] The positive electrode 20a and the negative electrode 20b are placed, for example, on a work table 40. Hereinafter, the positive electrode 20a and the negative electrode 20b may be collectively referred to simply as the electrodes 20. The electrodes 20 are made of, for example, a conductive metal material.

[0023] The positive electrode 20a is attached to a first end of the heating element 14. The negative electrode 20b is attached to a second end of the heating element 14 opposite the first end.

[0024] Each electrode 20 includes two electrode segments 50 and an electrode fixing member 52. The two electrode segments 50 are arranged opposite each other, and, for example, their opposing surfaces are flat. The end of the heating element 14 is arranged between the two electrode segments 50. The electrode fixing member 52 fixes the two electrode segments 50 to the work table 40 with the end of the heating element 14 arranged between the two electrode segments 50. The end of the heating element 14 is sandwiched between the two electrode segments 50.

[0025] The power supply device 22 is electrically connected to each of the electrodes 20. The power supply device 22 is configured to be able to apply a voltage to the electrodes 20. By applying a voltage to the electrodes 20, the power supply device 22 is able to pass a current between the electrodes 20 in the heating element 14.

[0026] Hereinafter, the flow of current may be referred to as “energization.” Furthermore, the direction in which current flows in the heating element 14 may be referred to as “energization direction.”

[0027] The heating element 14 generates heat when a current flows through it, that is, the temperature of the heating element 14 becomes higher when it is energized than when it is not energized.

[0028] The first adherend 10 and the second adherend 12 are disposed opposite each other. For example, the first adherend 10 is disposed on a work table 40. The second adherend 12 is disposed on the opposite side of the work table 40 from the first adherend 10.

[0029] The heating element 14 is disposed between the first adherend 10 and the second adherend 12. More specifically, the heating element 14 is disposed between a first welding surface 60 of the first adherend 10, which includes a resin, and a second welding surface 62 of the second adherend 12, which includes a resin. In this state, ends of the heating element 14 extend outward from the first adherend 10 and the second adherend 12, and are fixed to the respective electrodes 20. One of the two surfaces of the heating element 14 abuts against the first welding surface 60 of the first adherend 10. The other of the two surfaces of the heating element 14 abuts against the second welding surface 62 of the second adherend 12.

[0030] As described above, of the first adherend 10 and the second adherend 12, the second adherend 12 is placed on the opposite side of the heating element 14 from the work table 40. The pressurizing auxiliary jig 44 is placed on the surface of the second adherend 12 opposite to the surface that contacts the heating element 14. The pressurizing jig 42 is placed on the surface of the pressurizing auxiliary jig 44 opposite to the surface that contacts the second adherend 12.

[0031] The pressing jig 42 is formed, for example, in a columnar shape. The pressing auxiliary jig 44 is formed, for example, in a block shape having a surface that contacts the second adherend 12, and is attached to the tip of the pressing jig 42. Note that the shapes of the pressing auxiliary jig 44 and the pressing jig 42 are not limited to the shapes shown as examples, and may be any shape.

[0032] The pressure device 24 is connected to the pressure jig 42. The pressure device 24 is configured to be able to move the pressure jig 42 in a direction approaching the work table 40 by using a driving source such as hydraulic pressure.

[0033] That is, the pressure device 24 is configured to be able to apply pressure to at least one of the first adherend 10 and the second adherend 12 in a direction in which the first adherend 10 and the second adherend 12 approach each other via the pressure jig 42 and the pressure auxiliary jig 44. For example, in a mode in which the pressure auxiliary jig 44 is in contact with the second adherend 12, the pressure device 24 is configured to be able to apply pressure to the second adherend 12 via the pressure auxiliary jig 44.

[0034] Hereinafter, the direction in which pressure is applied by the pressure device 24 may be referred to as the pressure direction. The pressure direction corresponds to a direction substantially perpendicular to the first welding surface 60 and the second welding surface 62, in other words, a direction substantially perpendicular to the surface of the heating element 14.

[0035] For ease of explanation, the directions perpendicular to the current flow direction of the heating element 14 and the pressure direction of the pressure device 24 are sometimes referred to as the perpendicular directions. The first adherend 10 and the second adherend 12 are arranged to extend in the perpendicular directions, for example.

[0036] Alternatively, of the first adherend 10 and the second adherend 12, the second adherend 12 may be placed on the workbench 40, and the first adherend 10 may be placed on the opposite side of the workbench 40 with respect to the heating element 14. In this embodiment, the pressurizing auxiliary jig 44 is placed on the surface of the first adherend 10 opposite the surface that abuts against the heating element 14. In this embodiment, the pressurizing device 24 may be configured to be able to apply pressure to the first adherend 10 via the pressurizing jig 42 and the pressurizing auxiliary jig 44.

[0037] In addition, the workbench 40 may be omitted, and a pressure auxiliary jig 44 and a pressure jig 42 may be placed on both the first adherend 10 and the second adherend 12, and the pressure device 24 may apply pressure to both the first adherend 10 and the second adherend 12.

[0038] The pressure device 24 applies pressure to the first adherend 10 and the second adherend 12 while the heating element 14 is being heated by current flowing through it. As a result, the heat from the heating element 14 melts the first welding surface 60 of the first adherend 10 and the second welding surface 62 of the second adherend 12. As a result, the first welding surface 60 of the first adherend 10 is welded to the heating element 14, and the second welding surface 62 of the second adherend 12 is welded to the heating element 14. As a result, the first welding surface 60 of the first adherend 10 and the second welding surface 62 of the second adherend 12 are welded together via the heating element 14. In other words, resistance welding is performed in the welding device 1.

[0039] The control device 30 includes one or more processors and one or more memories connected to the processors. The memories include a ROM storing programs and the like and a RAM serving as a work area. The processors cooperate with the programs stored in the memories to control the entire welding device 1. For example, the control device 30 controls the power supply device 22 and the pressure device 24 to achieve resistance welding.

[0040] As described above, in resistance welding, the first welding surface 60 and the second welding surface 62 are melted, and the first adherend 10 and the second adherend 12 are pressurized by the pressure device 24. As a result, in resistance welding, some of the molten resin may leak out from the first welding surface 60 and the second welding surface 62 during welding. After welding is completed, the leaked resin solidifies and becomes burrs. In resistance welding, the quality of the weld may vary depending on the amount of burrs.

[0041] Therefore, the welding apparatus 1 of this embodiment is provided with a restraining jig 32. The restraining jig 32 may be formed, for example, in a plate shape or a block shape. The restraining jig 32 is arranged relative to the first welding surface 60 and the second welding surface 62 in two directions: the direction in which current flows through the heating element 14 and an orthogonal direction perpendicular to the direction in which current flows through the heating element 14. The restraining jig 32 is arranged adjacent to the first welding surface 60 and the second welding surface 62. The restraining jig 32 restrains the outflow of molten resin from the first welding surface 60 and the second welding surface 62.

[0042] 2 to 5, the restraining jig 32 is divided into a first portion 32a that is disposed in the current-carrying direction relative to the first welding surface 60 and the second welding surface 62, and a second portion 32b that is disposed in a direction perpendicular to the first welding surface 60 and the second welding surface 62. The first portion 32a and the second portion 32b are each formed as separate, independent members.

[0043] 4, the first portion 32a includes a positive electrode side segment 32a1 and a negative electrode side segment 32a2. The positive electrode side segment 32a1 is located between the welding surface and the positive electrode 20a. The positive electrode side segment 32a1 is disposed opposite the heating element 14 with the heating element 14 interposed therebetween and abuts against the heating element.

[0044] The positive electrode side segment 32a1 on the lower surface of the heating element 14 is adjacent to the end face of the first adherend 10 on the positive electrode 20a side. In other words, the positive electrode side segment 32a1 on the lower surface of the heating element 14 is adjacent to the boundary portion on the positive electrode 20a side of the first welding surface 60. The positive electrode side segment 32a1 on the lower surface of the heating element 14 blocks the outflow of resin that flows from the first welding surface 60 in a direction approaching the positive electrode 20a.

[0045] The positive electrode side segment 32a1 on the upper surface of the heating element 14 is adjacent to the end face of the second adherend 12 on the positive electrode 20a side. In other words, the positive electrode side segment 32a1 on the upper surface of the heating element 14 is adjacent to the boundary portion on the positive electrode 20a side of the second welding surface 62. The positive electrode side segment 32a1 on the upper surface of the heating element 14 blocks the outflow of resin that flows from the second welding surface 62 in a direction approaching the positive electrode 20a.

[0046] The negative electrode segment 32a2 is located between the welding surface and the negative electrode 20b. The negative electrode segment 32a2 is disposed opposite to the heating element 14 with the heating element 14 interposed therebetween and in contact with the heating element.

[0047] The negative electrode side segment 32a2 on the underside of the heating element 14 is adjacent to the end face of the first adherend 10 on the negative electrode 20b side. In other words, the negative electrode side segment 32a2 on the underside of the heating element 14 is adjacent to the boundary portion on the negative electrode 20b side of the first welding surface 60. The negative electrode side segment 32a2 on the underside of the heating element 14 blocks the outflow of resin that flows from the first welding surface 60 in a direction approaching the negative electrode 20b.

[0048] The negative electrode side segment 32a2 on the upper surface of the heating element 14 is adjacent to the end face of the second adherend 12 on the negative electrode 20b side. In other words, the negative electrode side segment 32a2 on the upper surface of the heating element 14 is adjacent to the boundary portion on the negative electrode 20b side of the second welding surface 62. The negative electrode side segment 32a2 on the upper surface of the heating element 14 blocks the outflow of resin that flows from the second welding surface 62 in a direction approaching the negative electrode 20b.

[0049] 5, the second portion 32b includes a first adherend side segment 32b1 and a second adherend side segment 32b2. The first adherend side segment 32b1 is adjacent to the end face of the first adherend 10 in the extension direction. In other words, the first adherend side segment 32b1 is adjacent to the boundary portion of the first welding surface 60 on the side of the end face of the first adherend 10 in the extension direction. The first adherend side segment 32b1 also abuts against the surface of the second adherend 12 on the first adherend 10 side. The first adherend side segment 32b1 blocks the outflow of resin from the welding surface in the orthogonal direction, away from the end face of the first adherend 10 in the extension direction.

[0050] The second adherend side segment 32b2 is adjacent to the end face in the extension direction of the second adherend 12. In other words, the second adherend side segment 32b2 is adjacent to the boundary portion of the second welding surface 62 on the side of the end face in the extension direction of the second adherend 12. The second adherend side segment 32b2 also abuts against the surface of the first adherend 10 on the side of the second adherend 12. The first adherend side segment 32b1 blocks the outflow of resin from the welding surface in the orthogonal direction, away from the end face in the extension direction of the second adherend 12.

[0051] 1 and other figures, the cover jig 34 is disposed so as to cover the restricting jig 32 and supports the restricting jig 32. The cover jig 34 is fixed to the workbench 40 by fastening members such as bolts. By fixing the cover jig 34 to the workbench 40, the restricting jig 32 is indirectly fixed to the workbench 40.

[0052] The restricting jig 32 may be directly fixed to the workbench 40 by bolts or the like. However, when the restricting jig 32 is directly fastened by the bolts, the position or posture of the restricting jig 32 may shift. On the other hand, when the restricting jig 32 is indirectly fixed by the cover jig 34, the position or posture of the restricting jig 32 can be prevented from shifting.

[0053] In this way, in the welding apparatus 1 of this embodiment, the restricting jig 32 is arranged to surround the periphery of the welding surface. Therefore, in the welding apparatus 1 of this embodiment, during welding, it is possible to prevent a portion of the molten resin from leaking out from the first welding surface 60 and the second welding surface 62. As a result, the welding apparatus 1 of this embodiment can stabilize the quality of welding.

[0054] Furthermore, in the welding apparatus 1 of this embodiment, the restraining jigs 32 are arranged not only in either the current-flow direction or the orthogonal direction relative to the welding surface, but also in two directions, the current-flow direction and the orthogonal direction, relative to the welding surface. Therefore, the welding apparatus 1 of this embodiment can improve the effect of suppressing resin outflow compared to an embodiment in which the restraining jigs 32 are arranged only in either the current-flow direction or the orthogonal direction relative to the welding surface. As a result, the welding apparatus 1 of this embodiment can improve the effect of stabilizing the welding quality.

[0055] In this example, the restraining jigs 32 are arranged so as to surround the entire periphery of the welded surface. However, the present invention is not limited to this example. For example, it is sufficient that the restraining jigs 32 are arranged in at least two directions, the current flow direction and the perpendicular direction, relative to the welded surface, and there may be a portion of the periphery of the welded surface where the restraining jigs 32 are not arranged.

[0056] In addition, here, the first portion 32 a and the second portion 32 b of the restricting jig 32 are separate and independent members. However, the restricting jig 32 may have a configuration in which the first portion 32 a and the second portion 32 b are integrated.

[0057] Incidentally, since the regulating jig 32 blocks the resin flowing out from the welding surface, heat exchange occurs at the interface between the regulating jig 32 and the resin on the welding surface.

[0058] Taking this into consideration, in the welding device 1 of this embodiment, the thermal conductivity of the material constituting the first portion 32a may be different from the thermal conductivity of the material constituting the second portion 32b in the restraining jig 32. In other words, in the welding device 1 of this embodiment, the first portion 32a and the second portion 32b may be made of different materials with different thermal conductivities.

[0059] As a result, the welding apparatus 1 of this embodiment can differentiate the degree of heat exchange at the interface of the welding surface in the current flow direction from the degree of heat exchange at the interface of the welding surface in the perpendicular direction. As a result, the welding apparatus 1 of this embodiment can set the temperature distribution of the welding surface to a desired temperature distribution by individually setting the thermal conductivities of the first portion 32 a and the second portion 32 b.

[0060] More specifically, in the welding device 1 of this embodiment, the first portion 32a may be made of a material having a higher thermal conductivity than the material that makes up the second portion 32b.

[0061] For example, the second portion 32b may be made of a material with a relatively low thermal conductivity, and the first portion 32a may be made of a material with a relatively higher thermal conductivity than the material of the second portion 32b. Note that the specific materials of the first portion 32a and the second portion 32b may be materials with a desired thermal conductivity.

[0062] If the thermal conductivity of the second portion 32b is relatively low, the amount of heat dissipated through the second portion 32b at the welding surface will be relatively small. In this case, even if heat dissipation occurs through the second portion 32b near the interface in the perpendicular direction at the welding surface, the effect is small, and the amount of temperature drop is small. As a result, the amount of temperature change along the perpendicular direction at the welding surface, i.e., the temperature gradient in the perpendicular direction, will be relatively small. Therefore, it is possible to maintain a roughly constant temperature distribution in the perpendicular direction at the welding surface.

[0063] Furthermore, if the thermal conductivity of the first portion 32a is relatively high, the amount of heat dissipated through the first portion 32a at the welding surface is relatively large. In this case, the temperature drop due to heat dissipation through the first portion 32a is large near the interface of the welding surface in the current-flow direction. On the other hand, near the center of the welding surface in the current-flow direction, the distance from the first portion 32a is large, so the effect of heat dissipation through the first portion 32a is reduced, and the temperature drop is small. In this case, the temperature near the center of the welding surface is high and decreases toward both ends in the current-flow direction (portions contacting the first portion 32a). The temperature change along the current-flow direction at the welding surface, i.e., the temperature gradient in the current-flow direction, is relatively large. Therefore, the temperature distribution along the current-flow direction at the welding surface can be made to vary significantly.

[0064] In this way, in the welding device 1 of this embodiment, by making the thermal conductivity of the first portion 32a higher than that of the second portion 32b, it is possible to control the temperature distribution along the current flow direction on the welding surface in particular.

[0065] The thermal conductivity of the first portion 32a may not necessarily be higher than that of the second portion 32b, but may be higher than that of the first portion 32a. In this case, the relatively high thermal conductivity of the second portion 32b allows the temperature distribution on the welding surface in the orthogonal direction to vary significantly. Furthermore, the relatively low thermal conductivity of the first portion 32a allows the temperature distribution on the welding surface in the current-carrying direction to be roughly constant.

[0066] For ease of explanation, the distance between the first welding surface 60 and the second welding surface 62 and the regulating jig 32 may be referred to as the clearance amount. In Fig. 4, the clearance amount between the first welding surface 60 and the second welding surface 62 and the first portion 32a of the regulating jig 32 is illustrated by an arrow C1. In Fig. 5, the clearance amount between the first welding surface 60 and the second welding surface 62 and the second portion 32b of the regulating jig 32 is illustrated by an arrow C2.

[0067] The clearance amount may be set based on at least one of an estimated value of the strength of the first adherend 10 and the second adherend 12 after welding, the thermal conductivity of the components that make up the regulating jig 32, and an estimated value of the temperature distribution at the first welding surface 60 and the second welding surface 62.

[0068] For example, if the clearance is relatively large, the amount of resin that flows out will be relatively large, which may result in the formation of relatively large burrs. On the other hand, if the clearance is relatively small, the amount of resin that flows out will be relatively small, which may result in the formation of relatively small burrs. It is presumed that the strength of the first adherend 10 and the second adherend 12 after welding will differ depending on the size of the burrs.

[0069] In light of this, in this embodiment, when the restricting jig 32 is placed, a clearance amount may be set so that the estimated strength values ​​of the first adherend 10 and the second adherend 12 after welding will be a desired value, and the restricting jig 32 may be set to that clearance amount. The clearance amount and the estimated strength values ​​of the first adherend 10 and the second adherend 12 after welding may be related in advance by experiment or simulation.

[0070] Furthermore, the higher the thermal conductivity of the regulating jig 32, the easier it is to dissipate heat from the welding surface. For example, if it is desired to set the temperature of the interface between the welding surface and the regulating jig 32 to a specific temperature, the higher the thermal conductivity of the regulating jig 32, the larger the clearance amount may be, and the lower the thermal conductivity of the regulating jig 32, the smaller the clearance amount may be.

[0071] In light of this, in the present embodiment, when the restricting jig 32 is placed, the amount of clearance may be set based on the thermal conductivity of the members constituting the restricting jig 32, and the restricting jig 32 may be set to have that amount of clearance. The amount of clearance and the thermal conductivity of the members constituting the restricting jig 32 may be related in advance by experiment or simulation.

[0072] Also, for example, if you want to use a specific material for the regulating jig 32, you can reduce the clearance amount if you want to lower the temperature at the interface with the regulating jig 32 on the welding surface, and increase the clearance amount if you do not want to lower the temperature at the interface.

[0073] In light of this, in the present embodiment, when the restricting jig 32 is placed, the clearance amount may be set based on estimated values ​​of the temperature distribution on the first welding surface 60 and the second welding surface 62, and the restricting jig 32 may be set to achieve that clearance amount. The clearance amount and the estimated values ​​of the temperature distribution on the first welding surface 60 and the second welding surface 62 may be associated in advance by experiment or simulation.

[0074] The clearance amount may be set based on an index that combines two or more of the above-mentioned estimated value of strength, the above-mentioned thermal conductivity, and the above-mentioned estimated value of temperature distribution.

[0075] In this embodiment, by setting the clearance amount in this manner, it is possible to suppress the outflow of resin from the welding surface while satisfying the desired welding conditions.

[0076] As described above, the regulating jig 32 is indirectly fixed to the workbench 40 by the cover jig 34. There is a certain amount of play, i.e., a gap, between the regulating jig 32 and the cover jig 34. Furthermore, the force that fixes the regulating jig 32 to the workbench 40 depends on the force that fixes the cover jig 34 to the workbench 40, specifically, the fastening force of the fastening members that fasten the cover jig 34 to the workbench 40.

[0077] During welding, the resin flowing out from the welding surface applies a force to the regulating jig 32 that presses the regulating jig 32 in a direction away from the welding surface. If the force fixing the regulating jig 32 is relatively small, the pressing force of the resin may overcome the force fixing the regulating jig 32, causing the regulating jig 32 to move in the direction of the pressing force of the resin. This effectively increases the amount of clearance, and increases the amount of resin that flows out.

[0078] In light of this, in the present embodiment, when the restricting jig 32 is fixed by the cover jig 34, the magnitude of the force for fixing the cover jig 34, i.e., the magnitude of the force for fixing the restricting jig 32, is set. In the present embodiment, the magnitude of the force for fixing the restricting jig 32 may be set based on the allowable amount of resin that flows out from the first welding surface 60 and the second welding surface 62.

[0079] For example, the force for fixing the regulating jig may be set to a larger value as the allowable amount of resin outflow is smaller, and may be set to a smaller value as the allowable amount is larger.

[0080] In this embodiment, by setting the force for fixing the regulating jig 32 in this manner, it is possible to prevent excessive effort from being required when setting up each component before welding, and it is possible to ensure an appropriate workload commensurate with the quality of the product.

[0081] Furthermore, the pressure-applying auxiliary jig 44 is disposed directly above the second welding surface 62, with the second adherend 12 interposed therebetween. This facilitates heat exchange between the pressure-applying auxiliary jig 44 and the entire welding surface. In light of this, in this embodiment, the thermal conductivity of the members constituting the pressure-applying auxiliary jig 44 may be set based on an estimated value of the temperature distribution on the welding surface.

[0082] In this embodiment, by setting the thermal conductivity of the pressure auxiliary jig 44 in this manner, the temperature distribution over the entire welding surface can be made closer to the desired distribution.

[0083] 6 is a flowchart illustrating the flow of the welding method using the welding apparatus 1 of this embodiment. Before welding is performed, each member is first set up (S10). The setting up may be performed by a worker, or at least a part of the setting up may be performed by a machine or device such as an industrial robot. The setting up will be described in detail later.

[0084] Next, the control device 30 sets a current profile including various welding conditions such as the voltage value of the voltage to be applied to the electrodes and the timing of pressure application (S11).

[0085] Next, when the welding execution start condition is met, the control device 30 causes the power supply device 22 to start applying voltage, thereby starting the energization of the heating element 14 (S12). The welding execution start condition may be, for example, receiving an input instructing the start of welding execution, or arriving at a set energization start time point.

[0086] Next, when the condition for starting pressurization is satisfied, the control device 30 causes the pressurizing device 24 to start pressurization (S13). The condition for starting pressurization may be, for example, that a time set in the energization profile has elapsed since the start of energization.

[0087] Next, when the energization termination condition is satisfied, the control device 30 terminates the energization by causing the power supply device 22 to stop applying voltage (S14). The energization termination condition may be, for example, that the pressurization time from the start of pressurization has elapsed a time set in the energization profile.

[0088] The control device 30 causes the pressure device 24 to stop applying pressure as the current supply is stopped (S15), thereby completing the welding of the first welding surface 60 of the first adherend 10 and the second welding surface 62 of the second adherend 12.

[0089] Fig. 7 is a flow chart for explaining the flow of setting each member, and Figs. 8 to 15 are perspective views for explaining the flow of setting each member.

[0090] First, as shown in FIGS. 7 and 8, the first adherend side segment 32b1 of the second portion 32b of the regulating jig 32 is placed on the work table 40 (S20).

[0091] The first adherend 10 is placed adjacent to the first adherend side segment 32b1 on the workbench 40 (S21). As a result, the end face of the first adherend 10 in the extending direction is adjacent to the first adherend side segment 32b1.

[0092] The negative electrode side segment 32a2 of the first part 32a of the restraining jig 32 is placed on the workbench 40 (S22). This negative electrode side segment 32a2 is positioned on the underside of the heating element 14. As a result, a part of the end face of the first adherend 10 on the negative electrode 20b side is adjacent to the negative electrode side segment 32a2.

[0093] 7 and 9, the positive electrode side segment 32a1 of the first portion 32a of the restraining jig 32 is placed on the workbench 40 (S23). This positive electrode side segment 32a1 is positioned on the underside of the heating element 14. As a result, a part of the end face of the first adherend 10 on the positive electrode 20a side is adjacent to the positive electrode side segment 32a1.

[0094] 7 and 10, the heating element 14 is placed so as to bridge between the positive electrode 20a and the negative electrode 20b (S24). More specifically, the heating element 14 is placed on the upper surface of the positive electrode segment 32a1, the upper surface of the first adherend 10, and the upper surface of the negative electrode segment 32a2 on the workbench 40. The portion of the first adherend 10 where the upper surface of the first adherend 10 and the lower surface of the heating element 14 overlap corresponds to the first welding surface 60.

[0095] Next, as shown in FIGS. 7 and 11, the second adherend side segment 32b2 of the second portion 32b of the regulating jig 32 is placed on the top surface of the first adherend 10 (S25).

[0096] 7 and 12, the second adherend 12 is placed on the upper surface of the heating element 14 and the upper surface of the first adherend side segment 32b1 (S26). The portion of the second adherend 12 where the lower surface of the second adherend 12 overlaps with the upper surface of the heating element corresponds to the second welding surface 62. As a result, the end face of the second adherend 12 in the extension direction is adjacent to the second adherend side segment 32b2.

[0097] 7 and 13, the negative electrode side segment 32a2 of the first portion 32a of the restraining jig 32 is placed on the upper surface of the heating element 14 (S27). As a result, a part of the end face of the second adherend 12 on the negative electrode 20b side is adjacent to the negative electrode side segment 32a2.

[0098] The positive electrode side segment 32a1 of the first portion 32a of the restraining jig 32 is placed on the upper surface of the heating element 14 (S28). As a result, a part of the end surface of the second adherend 12 on the positive electrode 20a side is adjacent to the positive electrode side segment 32a1.

[0099] Next, as shown in FIGS. 7 and 14, the cover jig 34 is placed so as to cover and conceal the various parts of the regulating jig 32, and is fixed to the workbench 40 by fastening members (S29).

[0100] 7 and 15, the tip of the pressure jig 42 is inserted into the through-hole 84 in the center of the cover jig 34, and the pressure jig 42 is positioned above the welding surface (S30). At this time, the pressure auxiliary jig 44 is attached in advance to the tip of the pressure jig 42, and the pressure auxiliary jig 44 comes into contact with the upper surface of the second adherend 12. In other words, the pressure jig 42 is positioned above the welding surface via the second adherend 12 and the pressure auxiliary jig 44.

[0101] The specific arrangement order of the components of the regulating jig 32 is not limited to the order illustrated in Fig. 7. As a result, the arrangement order of the components may be changed as appropriate within a range that allows the components of the regulating jig 32 to be arranged around the first welding surface 60 and the second welding surface 62.

[0102] As described above, the welding method of this embodiment includes a step of placing an electrically conductive heating element 14 between a first welding surface 60 of the first adherend 10, which includes a resin, and a second welding surface 62 of the second adherend 12, which includes a resin. The welding method of this embodiment includes a step of applying a voltage to electrodes 20 attached to the heating element 14 to pass a current through the heating element 14. After the step of passing a current through the heating element, the welding method of this embodiment includes a step of applying pressure to at least one of the first adherend 10 and the second adherend 12 in a direction that moves the first adherend 10 and the second adherend 12 toward each other, thereby welding the first welding surface 60 and the second welding surface 62 via the heating element 14. The welding method of this embodiment includes, prior to the step of passing an electric current through the heating element 14 and the step of welding the first welding surface 60 and the second welding surface 62 together, a step of positioning a regulating jig 32 adjacent to the first welding surface 60 and the second welding surface 62 in two directions relative to the first welding surface 60 and the second welding surface 62: the direction in which current flows through the heating element 14 and a perpendicular direction perpendicular to the direction in which current flows through the heating element 14.

[0103] In Figure 7, the process of positioning the first substrate side segment 32b1 (S20), the process of positioning the negative electrode side segment 32a2 (S22), the process of positioning the positive electrode side segment 32a1 (S23), the process of positioning the second substrate side segment 32b2 (S25), the process of positioning the negative electrode side segment 32a2 (S27), and the process of positioning the positive electrode side segment 32a1 (S28) are included in the process of positioning the above-mentioned regulating jig 32.

[0104] According to the welding method of this embodiment, the restricting jig 32 is arranged to surround the periphery of the welding surface. Therefore, the welding method of this embodiment can prevent a portion of the molten resin from leaking out from the first welding surface 60 and the second welding surface 62 during welding. As a result, the welding method of this embodiment can stabilize the quality of welding.

[0105] Furthermore, according to the welding method of this embodiment, the restraining jigs 32 are arranged not only in either the current-flow direction or the orthogonal direction relative to the welding surface, but also in two directions, the current-flow direction and the orthogonal direction, relative to the welding surface. Therefore, the welding method of this embodiment can improve the effect of suppressing resin outflow compared to an embodiment in which the restraining jigs 32 are arranged only in either the current-flow direction or the orthogonal direction relative to the welding surface. As a result, the welding method of this embodiment can improve the effect of stabilizing the welding quality.

[0106] 7, the above-described clearance amount may be set when each of the first adherend side segment 32b1, the second adherend side segment 32b2, the negative electrode side segment 32a2, and the positive electrode side segment 32a1 is positioned. In the welding method of this embodiment, the clearance amount may be set based on at least one of an estimated strength of the first adherend 10 and the second adherend 12 after welding, the thermal conductivity of the components constituting the restraining jig 32, and an estimated temperature distribution at the first welding surface 60 and the second welding surface 62. By setting the clearance amount in this manner, the welding method of this embodiment can suppress resin outflow from the welding surfaces while satisfying the desired welding conditions.

[0107] 7 , the magnitude of the force for fixing the regulating jig 32 may be set when the cover jig 34 is positioned and fixed. In the welding method of this embodiment, the magnitude of the force for fixing the regulating jig 32 may be set based on the allowable amount of resin that flows out from the first welding surface 60 and the second welding surface 62. In the welding method of this embodiment, setting the force for fixing the regulating jig 32 in this manner prevents excessive labor from being required when setting up each component before welding, and enables the workload to be appropriate for the quality of the product.

[0108] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0109] REFERENCE SIGNS LIST 1 welding device 10 first adherend 12 second adherend 14 heating element 20 electrode 22 power supply device 24 pressure device 32 regulating jig 32a first portion 32b second portion 60 first welding surface 62 second welding surface

Claims

1. A welding device comprising: a conductive heating element disposed between a first welding surface containing resin of a first adherend and a second welding surface containing resin of a second adherend; electrodes attached to the heating element; a power supply device that applies a voltage to the electrodes to pass an electric current through the heating element; a pressure device that applies pressure to at least one of the first and second adherends in a direction in which the first and second adherends approach each other when the heating element is heated by the current flowing through it, thereby welding the first welding surface and the second welding surface via the heating element; and restraining jigs disposed adjacent to the first welding surface and the second welding surface in two directions: the direction in which current flows through the heating element and an orthogonal direction perpendicular to the direction in which current flows through the heating element.

2. The welding device according to claim 1, wherein the regulating jig is divided into a first portion arranged in the current-carrying direction relative to the first and second welding surfaces, and a second portion arranged in the direction perpendicular to the first and second welding surfaces, and wherein the thermal conductivity of the material constituting the first portion is different from the thermal conductivity of the material constituting the second portion.

3. A welding method comprising the steps of: placing a conductive heating element between a first welding surface of a first adherend that includes resin, and a second welding surface of a second adherend that includes resin; applying a voltage to electrodes attached to the heating element to pass a current through the heating element; after the step of passing a current through the heating element, when the heating element has been heated by the current flowing through the heating element, applying pressure to at least one of the first adherend and the second adherend in a direction in which the first adherend and the second adherend approach each other, thereby welding the first welding surface and the second welding surface together via the heating element; and prior to the steps of passing a current through the heating element and welding the first welding surface and the second welding surface together, placing restraining jigs adjacent to the first welding surface and the second welding surface in two directions: the direction in which current flows through the heating element and a direction perpendicular to the direction of current flow through the heating element.

4. The welding method according to claim 3, wherein the regulating jig is divided into a first portion arranged in the current-carrying direction relative to the first and second welding surfaces, and a second portion arranged in the direction perpendicular to the first and second welding surfaces, and the thermal conductivity of the material constituting the first portion is different from the thermal conductivity of the material constituting the second portion.

5. A welding method as described in claim 3, wherein the amount of clearance between the first and second welding surfaces and the regulating jig is set based on at least one of an estimated value of the strength of the first and second adherends after welding, the thermal conductivity of the members constituting the regulating jig, and an estimated value of the temperature distribution on the first and second welding surfaces.

6. A welding method as described in claim 3, wherein the magnitude of the force for fixing the regulating jig is set based on the allowable amount of resin flowing out from the first welding surface and the second welding surface.

Images