JP2012227028A - Fusing method and fusing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fusing method and a fusing device for switching an energization current value to an electrode in exact timing, and shortening time required for fusing to improve work efficiency when an insulation coat is discharged from between a terminal and a conducting wire.SOLUTION: Current of a first current value is energized between both electrodes 6, 7 while sandwiching a terminal 2 and a conducting wire 1 between a pair of electrodes 6, 7 to be pressurized, when a voltage commutation point where a voltage value between both the electrode 6, 7 converts into a rise after a fall is detected in this energization, current of a second current value which is made larger than the first current value is energized between both the electrodes 6, 7 while pressurizing the terminal 2 and the conducting wire 1 by both the electrodes 6, 7.

Description

  The present invention relates to a fusing method and a fusing apparatus for coupling a terminal and a conductor with an insulating coating.

  In recent years, when joining a terminal and a conductive wire with an insulating coating, the terminal and the conductive wire are sandwiched between a pair of electrodes, and the terminal and the conductive wire are melted and discharged by resistance heating by pressing while energizing the electrodes. Fusing (thermal caulking) for welding in a conductive state is employed. Unlike brazing using solder, fusing has the advantage that a terminal and a conductor with an insulating coating can be joined without using lead.

  By the way, in fusing, it is necessary to supply a relatively large current to the electrode in order to weld the lead wire to the terminal. However, at the initial stage of energization to the electrode, the insulating coating is not melted, so the electrical If the resistance is large and a relatively large current is supplied to the electrode at this time, the insulating coating may be scattered due to rapid high-temperature heat generation.

  In order to avoid this, the electrode is energized with a relatively small current until the insulating coating such as enamel provided on the surface of the conductor is melted and discharged from between the terminal and the conductor by pressurizing both electrodes. After the insulating coating is discharged and the terminal and the conductive wire are electrically connected, the value of the current supplied to the electrode is switched halfway, such that the electrode is energized with a relatively large current.

  It is known that a timer is generally used for switching the current value to the electrode. In this case, the timer is set with a predicted time from the start of energization to the electrode until the insulating coating melts and is discharged from between the terminal and the conductor, and until the set time elapses from the start of energization to the electrode A relatively small current is supplied to the electrode, and a relatively large current is supplied to the electrode when the set time of the timer has elapsed.

  However, in practice, the time from the start of energization to the electrode until the insulating coating is discharged from between the terminal and the conductor varies depending on the state of the electrode and the like. Therefore, it is necessary to set a long time with a margin in consideration of such a fluctuating time in the timer, which disadvantageously increases the time required for fusing and lowers the work efficiency.

  In addition to this, it is known that by detecting the displacement between the electrodes, it is determined that the insulating coating has been discharged from between the terminal and the conductive wire, and at this point the current value is switched to the electrodes. (See Patent Document 1). In this method, since the insulation coating melted with the energization of both electrodes detects displacement between the electrodes when it is pushed out between the terminal and the conductive wire by pressurization of both electrodes, the method using the timer described above It is possible to switch the current value at an earlier time than that.

  However, the amount of displacement between the electrodes when the molten insulating coating is pushed out between the terminal and the conductor is not constant depending on the cross-sectional shape of the conductor, the thickness of the insulating coating, etc. In addition, there is a possibility that the determination result of the current value switching timing may vary. Furthermore, when the thickness of the insulating coating is small, the displacement between the electrodes is small (usually about 0.1 mm), and it is difficult to accurately detect this displacement. Cannot judge.

Japanese Patent No. 3680728

  In view of the above points, the present invention can switch the current value to the electrode at an accurate timing when the insulating coating is discharged from between the terminal and the conductive wire, reducing the time required for fusing. It is an object of the present invention to provide a fusing method and a fusing apparatus capable of improving work efficiency.

  The present invention is a fusing method for coupling a terminal and a conductive wire with an insulating coating, wherein the terminal and the conductive wire are sandwiched between a pair of electrodes and pressed, and a current having a first current value is applied between the electrodes. A voltage turning point by detecting a voltage turning point where the voltage value between both electrodes starts to rise after the voltage value between the two electrodes falls and a voltage turning point by the voltage turning detection step A second energization step of energizing a current of a second current value larger than the first current value between the electrodes while pressurizing the terminal and the conductor with both electrodes. It is characterized by that.

  Further, the present invention is a fusing device for realizing the above method, wherein a pair of electrodes sandwiching the terminal and the conductive wire, and the terminal and the conductive wire between the electrodes are pressurized via the electrode. Pressurizing means, a power supply for supplying power to the electrode sandwiching the terminal and the conductive wire, and a voltage change detecting means for detecting a voltage turning point at which the voltage value between the two electrodes decreases and then increases when energized by the power supply. And a current control means for switching the current supplied from the power source to the electrode from the first current value to a second current value larger than the first current value when the voltage change detection means detects a voltage turning point. It is characterized by providing.

  According to the present invention, first, the insulation coating of the conducting wire is melted by energization (first energization process) with a first current value between both electrodes. When the insulating coating melts, the insulating coating is pushed out from between the terminal and the conductive wire by the pressurization of both electrodes and discharged.

  In the initial stage of energization with the first current value, when the insulation coating is heated in an unmelted state, the voltage value between the two electrodes gradually rises, and the insulation coating is melted to insulate between the terminal and the conductor. When the coating starts to be pushed out, the voltage value between the two electrodes starts to gradually decrease. When the molten insulation coating is discharged from between the terminal and the conductor, the conductor and the terminal become conductive, current flows to the terminal through the conductor, and the resistance between the electrodes decreases, so the voltage between the two electrodes The value starts to rise (voltage turning point). That is, the voltage turning point occurs at the same time as the discharge of the insulation coating from between the terminal and the conductive wire is completed.

  When the voltage change point at this time is detected by the voltage change detection means (voltage change detection step), the current control means switches to energization with the second current value between the electrodes (second current supply step). ). By passing a current having a second current value larger than the first current value between the electrodes, the terminal and the conductor can be smoothly welded.

  As described above, in the present invention, since the voltage switching point generated at the same time as the completion of the discharge of the insulation coating from between the terminal and the conductive wire is detected and the current value supplied to the electrode is switched, the discharge of the insulation coating is performed. The current value can be switched immediately upon completion. Thereby, the time required for fusing can be shortened as much as possible, and the working efficiency is improved. In addition, by detecting the voltage turning point, the insulation coating is completely discharged and the current value is switched without being affected by the cross-sectional shape of the conducting wire, the thickness of the insulating coating, or the state of the electrode. Can be matched exactly.

  In addition, since the 1st electric current value supplied between both electrodes by the 1st electricity supply process is constant, both the resistance value between both electrodes and a voltage value change. Therefore, in the present invention, the change in the voltage value between the two electrodes is synonymous with the change in the resistance value between the two electrodes.

Explanatory top view which shows the conducting wire and terminal which are joined in embodiment of this invention. Explanatory drawing which shows the apparatus of this embodiment typically. Explanatory sectional drawing which shows a conducting wire and the principal part of a terminal. The flowchart which shows the principal part of the method of this embodiment. Explanatory drawing which shows the action | operation of the apparatus of this embodiment. The diagram which shows the change of the voltage between both electrodes in this embodiment.

  An embodiment of the present invention will be described with reference to a case where terminals 2 are joined to a plurality of flat conductors 1 which are coil wires extending from a motor (not shown). As shown in FIG. 1, the terminal 2 includes a cylindrical lead wire joint portion 3 into which the flat lead wire 1 can be inserted, and a connection terminal portion 4 integrally connected to the lead wire joint portion 3.

  As shown in FIG. 2, the fusing device 5 of the present embodiment includes a lower electrode 6 that comes into contact with the conducting wire joint 3 of the terminal 2 from below, and an upper electrode 7 that comes into contact with the conducting wire joint 3 of the terminal 2 from above. It has. The upper electrode 7 is provided in a pressurizing means 8 such as a cylinder, and the upper electrode 7 and the lower electrode 6 sandwich the conductor joint portion 3 of the terminal 2 to be in a pressurized state. The upper electrode 7 and the lower electrode 6 are connected to a power source 9 and energized.

  In addition, the fusing device 5 includes a control means 10 that controls the operation thereof. The control unit 10 includes a pressurization control unit 11 that controls the pressure applied by the pressurization unit 8, a displacement measurement unit 12 that measures the amount of displacement of the upper electrode 7 (the collapsed dimension of the conductor joint 3 of the terminal 2), and a power source 9, a power supply control unit 13 (current control means) for controlling the energization operation to both electrodes 6, 7, a voltage measurement unit 14 for measuring the voltage value between both electrodes 6, 7 during energization, and both electrodes 6, 7 The voltage conversion detection part 15 (voltage conversion detection means) which detects the voltage conversion point which changes to a rise after the voltage value of between falls is provided as a function.

  As shown in FIG. 3 (a), each flat wire 1 is a copper wire having a rectangular shape in cross section, and an insulating coating 16 such as enamel is provided on the outer surface thereof. Each of the rectangular conductive wires 1 is aligned in the lateral direction with the side surfaces 12 in close contact with each other, and as shown in FIG. 3B, the insulating coating 16 on the upper surface side is removed, and then, as shown in FIG. As shown, it is inserted into the conductor joint 3.

  Next, the fusing method according to the present embodiment will be described. First, as shown in FIG. 2, the conductor joining portion 3 of the terminal 2 into which a plurality of aligned rectangular conductors 1 are inserted is sandwiched between the upper electrode 7 and the lower electrode 6 of the fusing device 5, and the control means The pressurizing means 8 is operated by the pressurizing control unit 11 and pressure is started.

  Next, as shown in FIG. 4, the control means 10 energizes the electrodes 6 and 7 from the power supply 9 by the power supply control unit 13 in STEP 1. At this time, the power supply control unit 13 energizes a current having a preset first current value (for example, 6000 A) between the upper electrode 7 and the lower electrode 6 (first energization process). Subsequently, the control unit 10 proceeds to STEP 2 and starts measuring the voltage value between the electrodes 6 and 7 by the voltage measuring unit 14.

  As shown in FIG. 5 (a), each rectangular conducting wire 1 is provided with the insulating coating 16, so that the current at the initial stage of energization (shown by a broken line arrow in the figure) mainly flows through the conducting wire joint 3. Then, when the terminal 2 generates heat due to the resistance between the upper electrode 7 and the lower electrode 6 in each of the conductive wire joint portion 3 and each flat conductive wire 1, the resistance value between the electrodes 6 and 7 increases with this temperature increase, As shown in FIG. 6, the voltage value increases when the first current value is constant.

  Next, as shown in FIG. 4, the control means 10 determines whether or not the voltage value between the electrodes 6 and 7 is lowered by the voltage measurement unit 14 in STEP 3. Then, when melting of the insulating coating 16 of each flat wire 1 is started due to the heat generated in the terminal 2, as shown in FIG. 6, the resistance value between the electrodes 6 and 7 is lowered, so that the voltage value is reduced. Start to descend. When the decrease of the voltage value at this time is detected, the control means 10 proceeds to STEP 4 in FIG.

  When the control means 10 proceeds to STEP 4, the voltage change detection unit 15 starts monitoring the voltage change point (voltage change detection step). As the insulation coating 16 of each flat wire 1 is melted, the melted insulation coating 16 is discharged from between each flat wire 1 and the conductor joint 3 of the terminal 2, and electrical conduction of each flat wire 1 is ensured. The Accordingly, as shown in FIG. 6, the decrease in the resistance value between the electrodes 6 and 7 is stopped, the decrease in the voltage value is stopped, and furthermore, each rectangular wire 1 starts to generate heat, so that the resistance value is increased. Begins to rise slowly and the voltage value starts to rise (a voltage turning point occurs). Therefore, when the melted insulation coating 16 is discharged from between each flat wire 1 and the wire joint 3 of the terminal 2, a voltage turning point is generated.

  When the voltage switching point is detected in STEP 4 of FIG. 4 by the voltage switching detection unit 15, the control means 10 has discharged the melted insulating film 16 from between each flat wire 1 and the wire joint 3 of the terminal 2. Deemed, go to STEP5. In STEP 5, the control means 10 causes a current of a second current value (for example, 10000 A), which is larger than the first current value, to pass between the electrodes 6 and 7 via the power supply control unit 13 (first 2 electrification process), it progresses to STEP6. Thus, since the current value is switched when the voltage turning point is detected, the energization time can be shortened.

  When proceeding to STEP 6, the control means 10 starts measuring the displacement amount of the upper electrode 7 by the displacement measuring unit 12. During this time, the pressurized state by the pressurizing means 8 is maintained. Then, the control means 10 proceeds to STEP 7 and proceeds to STEP 8 when the displacement amount measured by the displacement measuring unit 12 is equal to or larger than the predetermined displacement amount. By switching to the second current value, each of the rectangular conducting wire 1 sandwiched between the electrodes 6 and 7 and the conducting wire joint portion 3 of the terminal 2 are softened, and as shown in FIG. The flat conductor 1 and the conductor joint 3 of the terminal 2 are both crushed and deformed, and fusing (heat caulking) is performed. In STEP 7, it is detected by the displacement amount measured by the displacement measuring unit 12 that fusing has been performed.

  Then, when proceeding to STEP 8, the control means 10 stops energization of both electrodes 6 and 7 by the power supply control unit 13. At the same time, although not shown, the measurement of the displacement amount of the upper electrode 7 by the displacement measuring unit 12 and the measurement of the voltage value between both electrodes 6 and 7 are stopped, and the pressurization by the pressurizing means 8 is released and both electrodes are stopped. 6 and 7 are separated.

  In the present embodiment, the terminal 2 provided with the cylindrical conductive wire joint portion 3 is described as an example. However, although not illustrated, the conductive wire joint portion divided into upper and lower portions is provided, and each rectangular wire is provided in the divided conductive wire joint portion. Even a terminal sandwiching the conductor 1 can be subjected to fusing using the method of the present invention.

  Further, in the present embodiment, the flat conducting wire 1 has been described, but the same effect can be obtained by adopting the present invention even with a round conducting wire having a circular cross section.

  Further, in the present embodiment, as shown in FIG. 3 (b), the insulating coating 16 on the upper surface side of each rectangular conducting wire 1 is removed prior to inserting each rectangular conducting wire 1 into the conducting wire joining portion 3. However, the fusing method of the present invention is not limited to this, and the same effect can be obtained even if the insulating coating 16 on the upper surface side of each rectangular conducting wire 1 is removed without being removed. it can.

  DESCRIPTION OF SYMBOLS 1 ... Conductive wire, 2 ... Terminal, 5 ... Fusing apparatus, 6 ... Lower electrode (electrode), 7 ... Upper electrode (electrode) 8 ... Pressurizing means, 9 ... Power supply, 13 ... Power supply control part (current control means), 15 ... Voltage change detection part (voltage change detection means), 16 ... Insulating film.

Claims (2)

A fusing method for connecting a terminal and a conductor with an insulating coating,
A first energization step of energizing a current of a first current value between the electrodes while sandwiching and pressing the terminal and the conductive wire between a pair of electrodes;
A voltage change detection step for detecting a voltage change point at which the voltage value between both electrodes starts to rise and then rises during energization in the first energization step;
When a voltage change point is detected by the voltage change detection step, a current having a second current value larger than the first current value is applied between both electrodes while pressing the terminal and the conductive wire with both electrodes. And a second energizing step. A fusing device that couples a terminal and a conductor with an insulating coating,
A pair of electrodes sandwiching the terminal and the conducting wire;
A pressurizing means for pressurizing the terminal and the conducting wire between the electrodes through the electrode;
A power source for supplying power to the electrode sandwiching the terminal and the conductive wire;
A voltage change detection means for detecting a voltage change point at which the voltage value between the two electrodes falls and then rises when energized by the power source; and
Current control means for switching a current supplied from the power source to the electrode from a first current value to a second current value larger than the first current value when the voltage change detection means detects a voltage turning point; A fusing device comprising:

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