Solid-phase welding device, control device, and control method

Abstract

To provide a solid-phase welding device, a control device, and a control method with which joining quality can be maintained even when a contact area cannot be contained within a reference range.SOLUTION: A control device 30 applies a load in a thickness direction to a first workpiece W10 and a second workpiece W20 by controlling a pair of pressure application shafts 11, 12, calculates a contact area of the first workpiece W10 and the second workpiece W20, in a state that the first workpiece W10 and the second workpiece W20 are in contact with each other, controls at least one out of the load applied to the first workpiece W10 and the second workpiece W20 and current flowing to a pair of electrodes 21, 22, and adjusts the contact area so as to be contained within the reference range.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a solid-state joining apparatus for joining a first workpiece and a second workpiece made of metal, a control device for controlling a solid-state joining device for joining the first workpiece and the second workpiece made of metal, and a control method for controlling the solid-state joining device. [Background technology]

[0002] Japanese Patent No. 7242112 (Patent Document 1) discloses a solid-phase spot joining device including a pressurizing mechanism including a pressing part and a current-carrying mechanism including a pair of welding electrodes. The solid-phase spot joining device disclosed in Japanese Patent No. 7242112 (Patent Document 1) is configured to press two metal plates in a direction perpendicular to the metal plates by the pressing part while the pair of welding electrodes are energized to heat each metal plate. In this specification, the joining method disclosed in Japanese Patent No. 7242112 (Patent Document 1), which joins the metals in a solid phase at a low temperature without melting them, thereby preventing a decrease in strength due to melting of the metals caused by a large current, is called "solid-phase joining". [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7242112 Summary of the Invention [Problem to be solved by the invention]

[0004] In the solid-state joining disclosed in Japanese Patent No. 7242112 (Patent Document 1), the occurrence of some kind of disturbance may cause the position of the pressing part to shift laterally, causing the contact area between the metal plates to deviate from the initially planned standard range, which may result in a decrease in joining quality. However, the solid-state spot joining device disclosed in Japanese Patent No. 724112 (Patent Document 1) does not take into account the effects of disturbances, and therefore cannot prevent a decrease in joining quality due to the contact area not falling within the standard range.

[0005] An object of the present disclosure is to provide a solid-state joining apparatus, a control device, and a control method that are capable of maintaining joining quality even when the contact area does not fall within a standard range. [Means for solving the problem]

[0006] A solid-state welding apparatus according to one aspect of the present disclosure includes a pair of pressure shafts for pressing a first workpiece and a second workpiece made of metal from both sides in a thickness direction, a pair of electrodes respectively arranged around the pair of pressure shafts, and a control device. The control device controls the pair of pressure shafts to apply a load to the first workpiece and the second workpiece in the thickness direction, calculates a contact area between the first workpiece and the second workpiece in a state in which the first workpiece and the second workpiece are in contact with each other, and controls at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the calculated contact area to adjust the contact area to fall within a reference range.

[0007] A control device according to an aspect of the present disclosure relates to a control device for controlling a solid-state joining machine for joining a first workpiece and a second workpiece made of metal. The solid-state joining machine includes a pair of pressure shafts for pressing the first workpiece and the second workpiece from both sides in the thickness direction, and a pair of electrodes arranged around the pair of pressure shafts. The control device includes a storage device and a calculation device for executing processing according to a program stored in the storage device. The calculation device controls the pair of pressure shafts to apply a load to the first workpiece and the second workpiece in the thickness direction, calculates a contact area between the first workpiece and the second workpiece in a state where the first workpiece and the second workpiece are in contact with each other, and controls at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the calculated contact area to adjust the contact area to fall within a reference range.

[0008] A control method according to one aspect of the present disclosure relates to a control method in which a computer controls a solid-state welding machine that joins a first workpiece and a second workpiece made of metal. The solid-state welding machine includes a pair of pressure shafts that press the first workpiece and the second workpiece from both sides in a thickness direction, and a pair of electrodes that are respectively arranged around the pair of pressure shafts. The control method includes, as processing executed by the computer, a step of controlling the pair of pressure shafts to apply a load to the first workpiece and the second workpiece in the thickness direction, a step of calculating a contact area between the first workpiece and the second workpiece in a state in which the first workpiece and the second workpiece are in contact with each other, and a step of controlling at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the contact area calculated in the calculation step to adjust the contact area to fall within a reference range. Effect of the Invention

[0009] According to the present disclosure, based on the calculated contact area, at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes is controlled to adjust the contact area so that it falls within a standard range, making it possible to maintain joining quality even if the contact area does not fall within the standard range. [Brief description of the drawings]

[0010] [Figure 1] 1A to 1C are diagrams illustrating a current application process in a solid-state bonding apparatus according to an embodiment of the present disclosure. [Diagram 2] 11A and 11B are diagrams for explaining a bonding process according to a contact area. [Diagram 3] 4 is a flowchart showing the control contents executed by the control device. [Figure 4] 10 is a flowchart showing the control contents executed by the control device in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0012] 1 is a diagram illustrating a schematic diagram of a current application process in a solid-state joining apparatus 1 according to an embodiment of the present disclosure. The solid-state joining apparatus 1 is an apparatus for applying current to multiple workpieces W10, W20 stacked on top of each other to form softened regions at the interfaces between the multiple workpieces W10, W20, and for plastically deforming the softened regions to join the multiple workpieces W10, W20 in a solid state without melting them.

[0013] The multiple workpieces W10, W20 include a first workpiece W10 and a second workpiece W20. Each of the workpieces W10, W20 is made of a metal such as iron or aluminum. Each of the workpieces W10, W20 is formed, for example, in a flat plate shape.

[0014] 1, the solid state bonding apparatus 1 includes a solid state bonding apparatus 10, a control device 30, and an ammeter 35. The solid state bonding apparatus 10 includes a pair of pressure shafts 11 and 12, a pair of electrodes 21 and 22, and a pressure sensor 40.

[0015] The pair of pressure applying shafts 11, 12 includes a first pressure applying shaft 11 and a second pressure applying shaft 12. The pair of pressure applying shafts 11, 12 can apply pressure to the first workpiece W10 and the second workpiece W20 from both sides in the thickness direction of the stacked plate-like workpieces. The pair of pressure applying shafts 11, 12 are driven by a drive source (such as a servo press machine) not shown.

[0016] The first pressure shaft 11 has an elongated shape. The first pressure shaft 11 can press the first workpiece W10 so that the first workpiece W10 is plastically deformed. Specifically, the first pressure shaft 11 can press the first workpiece W10 so that a protrusion W11 is formed on the first workpiece W10. The first pressure shaft 11 is made of, for example, tungsten carbide. In this embodiment, the first pressure shaft 11 is formed in a cylindrical shape. The first pressure shaft 11 has a pressing surface 11a that presses the first workpiece W10. The pressing surface 11a is an end surface of the first pressure shaft 11. The pressing surface 11a is formed in a circular shape.

[0017] The second pressure applying shaft 12 has the same configuration as the first pressure applying shaft 11. The second pressure applying shaft 12 is disposed in such a manner that the central axis of the second pressure applying shaft 12 is located on an extension of the central axis of the first pressure applying shaft 11, and the pressing surface 12a of the second pressure applying shaft 12 faces the pressing surface 11a of the first pressure applying shaft 11. The first pressure applying shaft 11 and the second pressure applying shaft 12 may have a shape other than a cylindrical shape.

[0018] The pressure sensor 40 is provided, for example, on the first pressurizing shaft 11. In this embodiment, a load cell is used as the pressure sensor 40. Note that the location where the pressure sensor 40 is installed is not limited to the first pressurizing shaft 11.

[0019] The pair of electrodes 21, 22 includes a first electrode 21 and a second electrode 22. The pair of electrodes 21, 22 can pass electricity through the first workpiece W10 and the second workpiece W20 while in contact with the first workpiece W10 and the second workpiece W20. A voltage and a current are supplied to the pair of electrodes 21, 22 from a power supply unit (not shown).

[0020] The first electrode 21 can contact a portion of the first workpiece W10 surrounding a portion of the first workpiece W10 that is pressed by the first pressure shaft 11. In this embodiment, the first electrode 21 is formed in a cylindrical shape surrounding the first pressure shaft 11. A gap is provided between the inner peripheral surface of the first electrode 21 and the outer peripheral surface of the first pressure shaft 11. The first electrode 21 is made of, for example, copper. The first electrode 21 has a contact surface 21a that contacts the first workpiece W10. The contact surface 21a is formed in an annular shape. The shape of the contact surface 21a is not limited to an annular shape.

[0021] The second electrode 22 has the same configuration as the first electrode 21. The second electrode 22 can come into contact with a portion of the second workpiece W20 surrounding a portion pressurized by the second pressurizing shaft 12. The second electrode 22 is disposed in such a manner that the central axis of the second electrode 22 is located on an extension of the central axis of the first electrode 21, and the contact surface 22a of the second electrode 22 faces the contact surface 21a of the first electrode 21.

[0022] The ammeter 35 detects the value of the current X flowing from the pair of electrodes 21, 22 to each of the protrusions W11, W21.

[0023] The control device 30 includes a calculation device 31, a memory 32, a storage device 33, and an input / output interface 34. These components are connected via a bus.

[0024] The arithmetic device 31 is a computing entity (computer) that executes a predetermined process. The arithmetic device 31 is composed of a processor such as a central processing unit (CPU), a micro-processing unit (MPU), a tensor processing unit (TPU), or a graphics processing unit (GPU). The processor, which is an example of the arithmetic device 31, has a function of executing a predetermined process by executing a predetermined program, but some or all of these functions may be implemented using a dedicated hardware circuit such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). The term "processor" is not limited to a processor in the narrow sense that executes a process using a stored program method such as a CPU, an MPU, a TPU, or a GPU, but may include a hardwired circuit such as an ASIC or an FPGA. The arithmetic device 31 is not limited to a von Neumann type computer such as a CPU or a GPU, but may be composed of a non-von Neumann type computer such as a quantum computer or an optical computer. The arithmetic device 31 as described above can also be read as a processing circuitry that executes a predetermined process. The computing device 31 may be configured as one chip or multiple chips. Furthermore, the processor and related processing circuits may be configured as multiple computers interconnected by wire or wirelessly via a local area network or a wireless network. The processor and related processing circuits may be configured as a cloud computer that performs remote calculations based on input data and outputs the results of the calculations to other devices in remote locations.

[0025] The memory 32 includes a storage area (for example, a working area) for storing program codes or work memories when the arithmetic unit 31 executes various programs. Examples of the memory 32 include volatile memories such as DRAM and SRAM, and non-volatile memories such as ROM and flash memory.

[0026] The storage device 33 stores various programs or various data executed by the arithmetic device 31. For example, the storage device 33 stores a control program 330 executed by the arithmetic device 31 to control the pair of pressure shafts 11, 12 and the pair of electrodes 21, 22. The storage device 33 may be one or more non-transitory computer readable media, or may be one or more computer readable storage media. Examples of the storage device 33 include a hard disk drive (HDD) and a solid state drive (SSD).

[0027] Values ​​acquired by acquisition units such as the pressure sensor 40 and ammeter 35 are input to the input / output interface 34 .

[0028] The control device 30 controls the pair of pressure applying shafts 11, 12 and the pair of electrodes 21, 22. Specifically, the control device 30 controls the load acting on the first workpiece W10 and the second workpiece W20 from each of the pair of pressure applying shafts 11, 12, the load acting on the first workpiece W10 and the second workpiece W20 from each of the pair of electrodes 21, 22, the voltage applied to the pair of electrodes 21, 22, and the pressing amount of the pair of pressure applying shafts 11, 12 and the pair of electrodes 21, 22. The control device 30 controls the voltage applied to the pair of electrodes 21, 22 to control the current X passed through the pair of electrodes 21, 22.

[0029] The control device 30 performs an operation of applying a load F (see FIG. 1) from the pair of pressure shafts 11, 12 to the first work W10 and the second work W20 so that protrusions W11, W21 that contact each other are formed on each of the first work W10 and the second work W20. The control device 30 also performs an operation of passing electricity through the first work W10 and the second work W20. Specifically, the control device 30 applies a load F to the first work W10 and the second work W20 from the pair of pressure shafts 11, 12, and also performs an operation of passing electricity through the first work W10 and the second work W20 in a state in which the contact surface 21a of the first electrode 21 is in contact with a portion of the first work W10 surrounding a portion of the first work W10 that is pressed by the first pressure shaft 11 and the contact surface 22a of the second electrode 22 is in contact with a portion of the second work W20 surrounding a portion of the second work W20 that is pressed by the second pressure shaft 12. The control device 30 controls so that a current X indicated by a dashed line flows between the pair of electrodes 21 and 22 via each of the protrusions W11 and W21.

[0030] Each of the protrusions W11, W21 is softened by the flow of the current X. In this embodiment, the control device 30 applies a load F to the first workpiece W10 and the second workpiece W20 while softening each of the protrusions W11, W21 by flowing the current X. As a result, in this embodiment, the first workpiece W10 and the second workpiece W20 can be joined at the positions of each of the protrusions W11, W21.

[0031] Next, differences in the joining process according to the contact area between the first work W10 and the second work W20 will be described. There is a possibility that the position of the pressed part of the pair of pressure shafts 11, 12 may shift sideways due to some disturbance. When the position of the pressed part shifts sideways, there is a possibility that the contact area of ​​each of the projections W11, W21 where the first work W10 and the second work W20 come into contact may deviate from the initially planned standard range.

[0032] For example, if the contact area does not reach the initially planned standard range, the joining area in the joining process may be smaller than initially planned, and the joining quality may be reduced. On the other hand, if the contact area exceeds the initially planned standard range, the current value may be insufficient, or the pressure applied to the contact area may be insufficient, and the joining quality may be reduced. Therefore, the solid-state joining apparatus 1 of the present disclosure is configured to maintain the joining quality even when the contact area is not included in the initially planned standard range by taking into account the change in the contact area. FIG. 2 is a diagram for explaining the joining process according to the contact area.

[0033] The control device 30 executes the joining process in the order of Fig. 2(A) to (D). As shown in Fig. 2(A), the pair of electrodes 21, 22 are fixed to the pair of pressure shafts 11, 12 by a spring 50. The biasing force of the spring 50 acts on each of the workpieces W10, W20 via the pair of electrodes 21, 22. The spring 50 is omitted from Fig. 2(B) and subsequent figures.

[0034] As shown in FIG. 2(A), the control device 30 moves the pair of pressure shafts 11, 12 toward each of the workpieces W10, W20. At this time, each of the workpieces W10, W20 is sandwiched between the pair of electrodes 21, 22. A contact load of, for example, 1 kN acts on each of the workpieces W10, W20 as a biasing force by the spring 50. The pair of electrodes 21, 22 is biased to a position protruding from the pair of pressure shafts 11, 12 toward each of the workpieces W10, W20 by about 1 mm. The pair of pressure shafts 11, 12 and the pair of electrodes 21, 22 are a mechanism that is entirely driven by one driving source (such as a servo press machine) not shown.

[0035] Next, as shown in Fig. 2(B), the control device 30 moves the pair of pressure shafts 11, 12 toward the workpieces W10, W20 and applies a load to each of the workpieces W10, W20 to form protrusions. The load to form protrusions is applied to each of the workpieces W10, W20, thereby forming each of the protrusions W11, W21.

[0036] Next, the control device 30 applies current to each of the protrusions W11, W21 as shown in Fig. 2(C). The control device 30 applies current to each of the protrusions W11, W21 formed at the contact portion of each of the workpieces W10, W20 to detect the resistance value of each of the protrusions W11, W21, and calculates the contact area based on the resistance value. A specific method of calculating the contact area will be described later.

[0037] 2(C1)-(C4) are diagrams showing the projections W11, W21. As shown in FIG. 2(C1), when the projections W11, W21 are formed without the pair of pressure shafts 11, 12 being laterally displaced, the contact area falls within a predetermined reference range S. An upper limit and a lower limit are set for the reference range S. When the contact area is equal to or greater than the lower limit and equal to or less than the upper limit, it can be said that the contact area falls within the reference range S.

[0038] When the contact area is within the reference range S, the control device 30 controls the current to flow between the pair of electrodes 21, 22 via each of the protrusions W11, W21, as shown in Fig. 2(D), thereby softening each of the protrusions W11, W21. Then, the control device 30 changes the pressing force of the pair of pressing shafts 11, 12 so that a joining load acts on each of the workpieces W10, W20 from the pair of pressing shafts 11, 12.

[0039] The workpieces W10, W20 are joined to each other at the positions of the protrusions W11, W21 by applying a joining load. Specifically, the softened regions of the protrusions W11, W21 (regions including the contact interface between the workpieces W10 and W20) are plastically deformed while being joined while the regions remain in a solid phase state.

[0040] 2(C2), when the pair of pressure shafts 11, 12 are displaced laterally due to the occurrence of some disturbance, and each protrusion W11, W21 is formed, the contact area becomes S1 which is smaller than S. When the contact area is not within the reference range S, the control device 30 controls at least one of the load applied to each workpiece W10, W20 and the current passed through the pair of electrodes 21, 22 to adjust the contact area so that it falls within the reference range S.

[0041] For example, the control device 30 executes at least one of the following controls: increasing the pressure of the pair of pressure shafts 11, 12; and passing a current through the pair of electrodes 21, 22 to soften the protrusions W11, W21. Specifically, the control device 30 controls the pair of pressure shafts 11, 12 to apply a load to each of the workpieces W10, W20, thereby increasing the contact area so that the contact area falls within the reference range S. Alternatively, the control device 30 controls the pair of pressure shafts 11, 12 to apply a load to each of the workpieces W10, W20 while controlling the pair of electrodes 21, 22 to pass a current through the pair of electrodes 21, 22, thereby increasing the contact area so that the contact area falls within the reference range S. The control device 30 may increase the contact area so that the contact area falls within the reference range S by controlling the pair of electrodes 21, 22 to pass a current through the pair of electrodes 21, 22 without applying a load to each of the workpieces W10, W20. This allows the control device 30 to bring the contact area closer to the reference range S from S1, as shown in FIG. 2(C3).

[0042] As shown in Fig. 2(C3), the control device 30 adjusts the contact area from S1 to the reference range S, then applies current to each of the protrusions W11, W21 to detect the resistance value of each of the protrusions W11, W21, and calculates the contact area based on the resistance value. When the contact area is within the reference range S, the control device 30 joins each of the workpieces W10, W20 at the positions of the protrusions W11, W21, as shown in Fig. 2(D).

[0043] The control device 30 executes at least one of the following controls: increasing the pressure of the pair of pressure shafts 11, 12 from the state in which the contact area is S1 shown in Fig. 2(C2), and passing a current to soften each of the protrusions W11, W21 to the pair of electrodes 21, 22. There are cases in which the control device 30 does not adjust the contact area well and increases the contact area to S2, which is larger than the reference range S, as shown in Fig. 2(C4).

[0044] As shown in Fig. 2(C4), the control device 30 applies a current to each of the protrusions W11, W21 to detect the resistance value of each of the protrusions W11, W21, and calculates the contact area based on the resistance value. When the contact area is a contact area S2 larger than the reference range S, the control device 30 executes the joining process shown in Fig. 2(D) so as to correspond to the contact area of ​​S2. Specifically, the control device 30 increases the pressure applied by the pair of pressure shafts 11, 12 so that a load corresponding to the contact area S2 acts on each of the workpieces W10, W20 from the pair of pressure shafts 11, 12 while applying a current larger than normal corresponding to the contact area S2 between the pair of electrodes 21, 22 via each of the protrusions W11, W21.

[0045] Here, a method for calculating the contact area will be described. As shown in Fig. 2(C1), if the length of each protrusion W11, W21 in the thickness direction is L, then there is a relationship of R = ρL / S. L is also the pressing amount of the pair of pressure shafts 11, 12 for forming each protrusion W11, W21. R is the resistance value of each protrusion W11, W21, ρ is the resistivity, which is a physical property value determined for each material, and S is the contact area. The resistance value R is calculated from the set voltage value and the value of the ammeter 35 according to Ohm's law.

[0046] The control device 30 adjusts the contact area to be within the reference range S, for example, by adjusting the current I. Here, the mass of each of the protrusions W11, W21 is calculated as gSL, where g is the gravitational acceleration. The amount of heat required for each of the protrusions W11, W21 to reach a temperature ΔT is calculated from cgSLΔT. c is the heat capacity, which is a physical property value determined for each material. Furthermore, the resistance heat generated by each of the protrusions W11, W21 is calculated as I, where t is the time for current flow. 2 Calculated from Rt.

[0047] cgSLΔT=I 2 To calculate I with the contact area as the reference range from the relationship between R and R, the formula is transformed as follows: I 2 =cgSLΔT / Rt. From the relationship R=ρL / S, I 2 =cgS 2ΔT / ρt, from which the required I can be calculated. Here, I, ΔT, and t other than the predetermined values ​​c, g, and ρ, and the contact area S that can be calculated by energization, are control parameters that can be controlled by the control device 30. The control device 30 changes the current value according to the change in the contact area based on the change in the contact area.

[0048] As described above, the control device 30 may control at least one of increasing the pressure of the pair of pressure shafts 11, 12 and passing a current to soften the protrusions W11, W21 through the pair of electrodes 21, 22 to keep the contact area within the reference range. Furthermore, the control device 30 may control the temperature change and current flow time of the protrusions W11, W21 to keep the contact area within the reference range.

[0049] Next, the process executed by the control device 30 will be specifically described. Fig. 3 is a flowchart showing the control contents executed by the control device 30. The process of the flowchart in Fig. 3 is repeatedly called as a subroutine from a main routine in the control of the control device 30 and executed. First, in step S (hereinafter simply referred to as "S") 1, the control device 30 moves the pair of pressure shafts 11, 12 toward the first workpiece W10 and the second workpiece W20.

[0050] Next, the control device 30 judges whether the pair of pressure shafts 11, 12 contact the first workpiece W10 and the second workpiece W20 (S2). For example, the control device 30 acquires the detection value of the pressure sensor 40, and judges that the pair of pressure shafts 11, 12 contact the first workpiece W10 and the second workpiece W20 based on an increase in the detection value. The control device 30 stores the contact position as a reference position in S2. When the control device 30 judges that the pair of pressure shafts 11, 12 are not in contact with the first workpiece W10 and the second workpiece W20 (NO in S2), it returns to the process of S1. When the control device 30 judges that the pair of pressure shafts 11, 12 are in contact with the first workpiece W10 and the second workpiece W20 (YES in S2), it proceeds to the process of S3.

[0051] In S3, the control device 30 presses the pair of pressure shafts 11, 12 to the formation positions of the protrusions W11, W21. Next, the control device 30 executes energization of the pair of electrodes 21, 22 to measure the contact area (S4). The control device 30 applies current to each of the protrusions W11, W21 formed at the contact portion of each of the workpieces W10, W20 via the pair of electrodes 21, 22 to detect the resistance value of each of the protrusions W11, W21, and calculates the contact area based on the resistance value from the relationship R=ρL / S.

[0052] Next, the control device 30 judges whether the calculated contact area falls within a predetermined reference range (S5). If the contact area falls within the reference range (YES in S5), the control device 30 controls the pair of pressure shafts 11, 12 to apply a load to the first workpiece W10 and the second workpiece W20 in the thickness direction while applying current for joining to the pair of electrodes 21, 22, and presses the pair of pressure shafts 11, 12 to the joining position, thereby joining the first workpiece W10 and the second workpiece W20 (S6).

[0053] Next, the control device 30 judges whether the pair of pressure shafts 11, 12 have reached a set joining position (S7). For example, the control device 30 may judge whether the pair of pressure shafts 11, 12 have moved from the contact position stored in S2 to the joining position where the first workpiece W10 and the second workpiece W20 are joined, based on the pressing amount of the pair of pressure shafts 11, 12.

[0054] When the control device 30 determines that the pair of pressure shafts 11, 12 have not reached the joining position (NO in S7), the process returns to S6. When the control device 30 determines that the pair of pressure shafts 11, 12 have reached the joining position (YES in S7), the process returns from the subroutine to the main routine.

[0055] If the contact area does not fall within the reference range in S5 (NO in S5), the control device 30 applies a load in the thickness direction to the first workpiece W10 and the second workpiece W20 while applying current to the pair of electrodes 21, 22 to enlarge the contact area, and presses the pair of pressure shafts 11, 12 so that the contact area falls within the reference range (S8). Next, the control device 30 applies current to the pair of electrodes 21, 22 to measure the contact area (S9).

[0056] Next, the control device 30 judges whether the calculated contact area falls within a predetermined reference range (S10). If the contact area falls within the reference range (YES in S10), the control device 30 proceeds to processing in S6. If the contact area does not fall within the reference range (NO in S10), the control device 30 applies a load in the thickness direction to the first workpiece W10 and the second workpiece W20 while applying a current corresponding to the increased contact area to the pair of electrodes 21, 22, controls the pair of pressure shafts 11, 12, and presses the pair of pressure shafts 11, 12 in a manner corresponding to the increased contact area (S11), and proceeds to processing in S6.

[0057] 3, the solid-state welding apparatus 1 of the present embodiment adjusts the contact area to fall within a reference range by controlling at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21 and 22 based on the contact area calculated in S4 and S9. This allows the solid-state welding apparatus 1 to maintain the welding quality even if the contact area changes from the initially planned contact area.

[0058] Next, a modified example of the process executed by the control device 30 will be described. Fig. 4 is a flowchart showing the control contents executed by the control device 30 in the modified example. The process in Fig. 4 differs from the control in Fig. 3 in that the control device 30 measures the temperature of the softened portion of each of the protrusions W11, W21 when current is applied to expand the contact area.

[0059] As shown in FIG. 4, the control device 30 moves the pair of pressure shafts 11, 12 toward the first workpiece W10 and the second workpiece W20 (S21). Next, the control device 30 judges whether the pair of pressure shafts 11, 12 contact the first workpiece W10 and the second workpiece W20 (S22). The control device 30 stores the contact position as a reference position in S22. When the control device 30 judges that the pair of pressure shafts 11, 12 are not in contact with the first workpiece W10 and the second workpiece W20 (NO in S22), it returns to the process of S21. When the control device 30 judges that the pair of pressure shafts 11, 12 are in contact with the first workpiece W10 and the second workpiece W20 (YES in S22), it proceeds to the process of S23.

[0060] In S23, the control device 30 pushes the pair of pressure shafts 11, 12 to the formation position of the protrusions W11, W21. Next, the control device 30 applies current to the pair of electrodes 21, 22 to measure the contact area (S24). Next, the control device 30 determines whether the calculated contact area falls within a predetermined reference range (S25). If the contact area falls within the reference range (YES in S25), the control device 30 applies current to the pair of electrodes 21, 22 for joining, while controlling the pair of pressure shafts 11, 12 to apply a load in the thickness direction to the first workpiece W10 and the second workpiece W20, and pushes the pair of pressure shafts 11, 12 to the joining position, thereby joining the first workpiece W10 and the second workpiece W20 (S26).

[0061] Next, the control device 30 judges whether the pair of pressure shafts 11, 12 have reached the set joining position (S27). If the control device 30 judges that the pair of pressure shafts 11, 12 have not reached the joining position (NO in S27), the process returns to S26. If the control device 30 judges that the pair of pressure shafts 11, 12 have reached the joining position (YES in S27), the process returns from the subroutine to the main routine.

[0062] If the contact area does not fall within the reference range in S25 (NO in S25), the control device 30 applies current to the pair of electrodes 21, 22 to expand the contact area (S28). Next, the control device 30 measures the temperature of the softened portion of each of the protrusions W11, W21 (S29). Any method may be used to measure the temperature of the softened portion. For example, the temperature of the softened portion may be measured by a method that calculates the temperature from the waveform of ultrasonic waves generated when a laser is irradiated to the softened portion.

[0063] Next, the control device 30 judges whether the temperature of the softened portion has reached a predetermined reference value (S30). If the temperature of the softened portion has not reached the reference value in S30 (NO in S30), the control device 30 returns to the process of S28. If the temperature of the softened portion has reached the reference value in S30 (YES in S30), the control device 30 presses the pair of pressure shafts 11, 12 so that the contact area falls within the reference range (S31), and proceeds to the process of S26.

[0064] 4, the solid-state welding apparatus 1 of the modified example measures the temperature of the softened part and judges whether the temperature of the softened part has reached a reference value, and can calculate the remaining amount of heat to be given to the softened part. This allows the solid-state welding apparatus 1 of the modified example to make detailed adjustments so that the contact area falls within a reference range, taking into account the temperature of the softened part, and can maintain the joining quality even if the contact area changes from the initially planned contact area.

[0065] <Summary> (1) The solid-state joining apparatus 1 of the present disclosure includes a pair of pressure shafts 11, 12 that press a first workpiece W10 and a second workpiece W20 made of metal from both sides in the thickness direction, a pair of electrodes 21, 22 that are respectively arranged around the pair of pressure shafts 11, 12, and a control device 30. The control device 30 controls the pair of pressure shafts 11, 12 to apply a load to the first workpiece W10 and the second workpiece W20 in the thickness direction, calculates a contact area between the first workpiece W10 and the second workpiece W20 in a state in which the first workpiece W10 and the second workpiece W20 are in contact with each other, and controls at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22 based on the calculated contact area to adjust the contact area to fall within a reference range.

[0066] According to the solid-state joining apparatus 1 of the present disclosure, the contact area can be adjusted to fall within a reference range based on the calculated contact area by controlling at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22. This makes it possible to maintain the joining quality even if the contact area changes from the initially planned contact area.

[0067] (2) In the solid-state joining apparatus 1 of (1), the control device 30 determines whether the calculated contact area falls within a reference range, and if the contact area falls within the reference range, a predetermined current is passed through the pair of electrodes 21, 22 while controlling the pair of pressure shafts 11, 12 to apply a load in the thickness direction to the first workpiece W10 and the second workpiece W20, thereby joining the first workpiece W10 and the second workpiece W20.

[0068] According to the solid-state joining apparatus 1 of the present disclosure, when the contact area falls within a reference range, the first workpiece W10 and the second workpiece W20 can be joined by applying a load in the thickness direction to the first workpiece W10 and the second workpiece W20 by controlling the pair of pressure shafts 11, 12 while passing a predetermined current through the pair of electrodes 21, 22. This makes it possible to maintain the joining quality.

[0069] (3) In the solid-state joining apparatus 1 of (1), the control device 30 determines whether the calculated contact area falls within a standard range, and if the contact area does not fall within the standard range, adjusts the contact area so that it falls within the standard range, and then calculates the contact area between the first workpiece W10 and the second workpiece W20 again.

[0070] According to the solid-state welding apparatus 1 of the present disclosure, when the contact area does not fall within the reference range, the contact area between the first workpiece W10 and the second workpiece W20 can be calculated again after adjusting the contact area so that it falls within the reference range. This allows the contact area to be adjusted so that it falls within the reference range.

[0071] (4) In the solid-state joining apparatus 1 of (3), the control device 30 adjusts the contact area so that it falls within a reference range, and then determines whether the adjusted contact area falls within the reference range. If the adjusted contact area does not fall within the reference range, a current corresponding to the adjusted contact area is passed through the pair of electrodes 21, 22 while controlling the pair of pressure shafts 11, 12 to apply a load in the thickness direction to the first workpiece W10 and the second workpiece W20, thereby joining the first workpiece W10 and the second workpiece W20.

[0072] According to the solid-state joining apparatus 1 of the present disclosure, after adjusting the contact area so that it falls within a reference range, it is determined whether the adjusted contact area falls within the reference range, and if the adjusted contact area does not fall within the reference range, a pair of pressure shafts 11, 12 are controlled to apply a load in the thickness direction to the first workpiece W10 and the second workpiece W20 while passing a current according to the adjusted contact area through the pair of electrodes 21, 22, thereby joining the first workpiece W10 and the second workpiece W20. This makes it possible to maintain the joining quality even if the contact area becomes larger than the initially planned contact area.

[0073] (5) The solid-state joining apparatus 1 of (1) to (4) further includes a temperature measuring device that measures the temperature of the contact portion between the first workpiece W10 and the second workpiece W20. Based on the contact area and the measurement value of the temperature measuring device, the control device 30 controls at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22 to adjust the contact area to fall within a reference range.

[0074] According to the solid-state joining apparatus 1 of the present disclosure, the contact area can be adjusted to fall within a reference range by controlling at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22 based on the contact area and the measurement value of the temperature measuring device. This allows detailed adjustment so that the contact area falls within the reference range, taking into account the temperature of the softened portion, which is the contact portion, and makes it possible to maintain the joining quality even if the contact area changes from the initially planned contact area.

[0075] (6) In the solid-state joining apparatus 1 of (1) to (5), the control device 30 passes an electric current through a protrusion formed at the contact portion between the first workpiece W10 and the second workpiece W20 to detect a resistance value of the protrusion, and calculates the contact area based on the resistance value.

[0076] According to the solid-state welding apparatus 1 of the present disclosure, the contact area can be calculated based on the resistance value, and therefore the contact area can be easily obtained.

[0077] (7) The present disclosure relates to a control device 30 that controls a solid-state welding apparatus 10 that joins a first workpiece W10 and a second workpiece W20 made of metal. The solid-state welding apparatus 10 includes a pair of pressure shafts 11, 12 that press the first workpiece W10 and the second workpiece W20 from both sides in the thickness direction, and a pair of electrodes 21, 22 that are respectively arranged around the pair of pressure shafts 11, 12. The control device 30 includes a storage device 33 and a calculation device 31 that executes processing in accordance with a control program 330 stored in the storage device 33. The calculation device 31 controls a pair of pressure axes 11, 12 to apply a load in the thickness direction to the first work W10 and the second work W20, calculates the contact area between the first work W10 and the second work W20 when the first work W10 and the second work W20 are in contact with each other, and controls at least one of the loads applied to the first work W10 and the second work W20 and the currents passed through the pair of electrodes 21, 22 based on the calculated contact area, to adjust the contact area so that it falls within a standard range.

[0078] According to the control device 30 of the present disclosure, based on the calculated contact area, at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22 can be controlled to adjust the contact area so that it falls within a reference range. This makes it possible to maintain the joining quality even if the contact area changes from the initially planned contact area.

[0079] (8) The present disclosure relates to a control method in which a calculation device 31, which is a computer, controls a solid-state welding apparatus 10 that joins a first workpiece W10 and a second workpiece W20 made of metal. The solid-state welding apparatus 10 includes a pair of pressure shafts 11, 12 that press the first workpiece W10 and the second workpiece W20 from both sides in the thickness direction, and a pair of electrodes 21, 22 that are respectively disposed around the pair of pressure shafts 11, 12. The control method includes, as processing executed by a calculation device 31 which is a computer, the steps of controlling a pair of pressure axes 11, 12 to apply a load in the thickness direction to the first workpiece W10 and the second workpiece W20, calculating a contact area between the first workpiece W10 and the second workpiece W20 while the first workpiece W10 and the second workpiece W20 are in contact with each other, and controlling at least one of the loads applied to the first workpiece W10 and the second workpiece W20 and the currents passed through the pair of electrodes 21, 22 based on the contact area calculated in the calculation step, to adjust the contact area so that it falls within a reference range.

[0080] According to the control method of the present disclosure, the contact area can be adjusted to fall within a reference range by controlling at least one of the load applied to the first workpiece W10 and the second workpiece W20 and the current passed through the pair of electrodes 21, 22 based on the calculated contact area. This makes it possible to maintain the joining quality even if the contact area changes from the initially planned contact area.

[0081] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0082] 1 solid-state bonding apparatus, 10 solid-state bonding equipment, 11, 12 pressure shaft, 11a, 12a pressing surface, 21, 22 electrode, 21a, 22a contact surface, 30 control device, 31 calculation device, 32 memory, 33 storage device, 34 input / output interface, 35 ammeter, 40 pressure sensor, 50 spring, 330 control program, F load, X current, W10, W20 workpiece, W11, W21 protrusion.

Claims

1. A pair of pressure shafts that press the first workpiece and the second workpiece made of metal from both sides in a thickness direction; A pair of electrodes disposed around the pair of pressure shafts, respectively; a control device; The control device includes: a load is applied to the first workpiece and the second workpiece in the thickness direction by controlling the pair of pressure shafts; Calculating a contact area between the first workpiece and the second workpiece in a state where the first workpiece and the second workpiece are in contact with each other; a solid-state joining apparatus that adjusts the contact area so that it falls within a reference range by controlling at least one of a load applied to the first workpiece and the second workpiece and a current passed through the pair of electrodes based on the calculated contact area.

2. The control device includes: determining whether the calculated contact area falls within the reference range; 2. The solid-state joining apparatus according to claim 1, wherein, when the contact area falls within the reference range, a predetermined current is passed through the pair of electrodes while the pair of pressure shafts are controlled to apply a load to the first workpiece and the second workpiece in the thickness direction, thereby joining the first workpiece and the second workpiece.

3. The control device includes: determining whether the calculated contact area falls within the reference range; 2. The solid-state joining apparatus according to claim 1, wherein, when the contact area does not fall within the reference range, the contact area is adjusted so that it falls within the reference range, and then the contact area between the first workpiece and the second workpiece is calculated again.

4. The control device includes: After adjusting the contact area so that it falls within the reference range, it is determined whether or not the adjusted contact area falls within the reference range; 4. The solid-state joining apparatus according to claim 3, wherein, when the contact area after the adjustment does not fall within the reference range, a current according to the contact area after the adjustment is applied to the pair of electrodes while controlling the pair of pressure shafts to apply a load to the first workpiece and the second workpiece in the thickness direction, thereby joining the first workpiece and the second workpiece.

5. Further comprising a temperature measuring device for measuring a temperature of a contact portion between the first workpiece and the second workpiece, 2. The solid-state joining apparatus according to claim 1, wherein the control device controls at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the contact area and the measurement value of the temperature measuring device, to adjust the contact area so that it falls within the reference range.

6. 2. The solid-state joining apparatus according to claim 1, wherein the control device passes an electric current through a protrusion formed at a contact portion between the first workpiece and the second workpiece to detect a resistance value of the protrusion, and calculates the contact area based on the resistance value.

7. A control device that controls a solid-state joining device that joins a first workpiece and a second workpiece made of metal, The solid-state bonding equipment includes: A pair of pressure shafts that press the first workpiece and the second workpiece from both sides in a thickness direction; a pair of electrodes disposed around the pair of pressure shafts, The control device includes: A storage device; a computing device that executes processing according to the program stored in the storage device, The computing device includes: a load is applied to the first workpiece and the second workpiece in the thickness direction by controlling the pair of pressure shafts; Calculating a contact area between the first workpiece and the second workpiece in a state where the first workpiece and the second workpiece are in contact with each other; A control device that adjusts the contact area so that it falls within a reference range by controlling at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the calculated contact area.

8. A control method in which a computer controls a solid-state joining device that joins a first workpiece and a second workpiece made of metal, comprising: The solid-state bonding equipment includes: A pair of pressure shafts that press the first workpiece and the second workpiece from both sides in a thickness direction; a pair of electrodes disposed around the pair of pressure shafts, The control method includes: The process executed by the computer is controlling the pair of pressure shafts to apply a load to the first workpiece and the second workpiece in the thickness direction; calculating a contact area between the first workpiece and the second workpiece in a state in which the first workpiece and the second workpiece are in contact with each other; and controlling at least one of the load applied to the first workpiece and the second workpiece and the current passed through the pair of electrodes based on the contact area calculated by the calculating step, thereby adjusting the contact area so that it falls within a reference range.

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