Manufacturing method of wire bundle and manufacturing method of wire connection body

Abstract

To provide a manufacturing method of a wire bundle, capable of suppressing propagation of an ultrasonic vibration to a terminal metal fitting with a simpler method.SOLUTION: A manufacturing method of a wire bundle in which an electric wire 10 with a plurality of terminals formed by connecting a terminal metal fitting 30 to one end of an electric wire 20 of which a conductor 21 is coated with an insulation coated part 22, includes: a step of expanding the insulation coated part by heating the insulation coated part in the electric wire with the plurality of terminals; and a step of performing an ultrasonic bonding of a plurality of conductors by applying the an ultrasonic vibration to the plurality of conductors exposed from the electric wire with the plurality of terminals in a state where the insulation coated part is expanded.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an electric wire bundle and a method for manufacturing an electric wire joint. [Background technology]

[0002] Conventionally, a method has been proposed for connecting multiple electric wires without using connecting parts such as connectors, in which multiple conductors exposed from the ends of multiple electric wires are directly joined to form a conductor joint. Specifically, multiple conductors are set together in a joining machine for joining conductors, and the conductors are joined by ultrasonic joining.

[0003] Here, when an electric wire with a terminal having a terminal metal fitting crimped to its end is used as the electric wire, when ultrasonic vibration is applied to the electric wire with a terminal, the vibration propagates through the conductor to the terminal metal fitting, and there is a risk of breakage at a relatively weak point such as a bent portion of the terminal metal fitting. For this reason, Patent Document 1 proposes a technique for reducing the propagation of vibration to the terminal metal fitting to suppress damage to the terminal metal fitting. Specifically, the patent document discloses a method for manufacturing an electric wire with a terminal, in which a terminal metal fitting is connected to one end of an electric wire having a conductor covered with an outer sheath, a middle part of the electric wire is clamped between a pair of plates, and ultrasonic vibration is applied to the conductor exposed at the other end of the electric wire to perform ultrasonic bonding processing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-177863 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, each electric wire is clamped by a pair of jigs (plates) to prevent the vibration from propagating to the terminal fitting. However, in order to prevent the vibration from propagating, each electric wire needs to be sufficiently pressurized by the jigs, and therefore it is desirable to use a jig suited to each electric wire. Therefore, there is a demand for a simpler method to prevent the ultrasonic vibration from propagating to the terminal fitting.

[0006] The present invention has been made in consideration of the problems inherent in the conventional techniques, and an object of the present invention is to provide a method for manufacturing an electric wire bundle and an electric wire joint body that are capable of suppressing the propagation of ultrasonic vibration to a terminal fitting in a simpler manner. [Means for solving the problem]

[0007] A method for manufacturing an electric wire bundle according to a first aspect of the present invention is a method for manufacturing an electric wire bundle in which a plurality of electric wires with terminals are joined to each other, each of which has a conductor covered with an insulating coating and a terminal fitting connected to one end of the electric wire, and includes a step of heating the insulating coating of the plurality of electric wires with terminals to expand the insulating coating, and a step of ultrasonically joining the plurality of conductors to each other by applying ultrasonic vibrations to the plurality of conductors exposed from the plurality of electric wires with terminals while the insulating coating is in an expanded state.

[0008] A manufacturing method for an electric wire joint according to a second aspect of the present invention is a manufacturing method for an electric wire joint in which a terminal-attached electric wire, which is formed by connecting a terminal fitting to one end of an electric wire having a conductor covered with an insulating coating, and a conductive member are joined together, and the manufacturing method for the electric wire joint includes a step of heating the insulating coating in the electric wire with terminal to expand the insulating coating, and a step of applying ultrasonic vibrations to the conductor exposed from the electric wire with terminal while the insulating coating is in an expanded state, thereby ultrasonically joining the conductor and the conductive member. Effect of the Invention

[0009] According to the present invention, it is possible to provide a method for manufacturing an electric wire bundle and a method for manufacturing an electric wire joint that are capable of suppressing the propagation of ultrasonic vibration to a terminal fitting in a simpler manner. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 2 is a perspective view illustrating an example of an electric wire with a terminal used in the method for producing an electric wire bundle according to the present embodiment. [Figure 1B] FIG. 2 is a schematic view showing a cross section of a terminal fitting in an electric wire with a terminal. [Diagram 2] 1 is a schematic diagram showing a state in which a plurality of electric wires with terminals are placed on an ultrasonic bonding device in a manufacturing method for an electric wire bundle according to the present embodiment. FIG. [Diagram 3] FIG. 4 is a schematic diagram showing a state in which a plurality of electric wires with terminals are heated in the method for producing an electric wire bundle according to the present embodiment. [Figure 4] 4 is a schematic diagram showing a state in which a plurality of electric wires with terminals are ultrasonically joined while being heated in the method for producing an electric wire bundle according to the present embodiment. FIG. [Diagram 5] FIG. 11 is a schematic diagram showing another example of a state in which a plurality of electric wires with terminals are heated in the method for producing an electric wire bundle according to the present embodiment. [Figure 6] FIG. 11 is a schematic diagram showing another example of a state in which a plurality of electric wires with terminals are heated in the method for producing an electric wire bundle according to the present embodiment. [Figure 7] 3 is a schematic diagram showing a state in which the electric wire with terminal is heated in the manufacturing method of the electric wire joint body according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the method for producing an electric wire bundle and the method for producing an electric wire joint body according to the present embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0012] [Method of manufacturing electric wire bundle] The method for producing an electric wire bundle according to the present embodiment is a method for producing an electric wire bundle by directly joining together the conductors of a plurality of electric wires with terminals 10. As shown in Fig. 1A and Fig. 1B, the electric wire with terminal 10 includes an electric wire 20 and a terminal fitting 30 connected to one end of the electric wire 20.

[0013] The electric wire 20 is an insulated electric wire including a conductor 21 and an insulating coating 22 that covers the conductor 21. The conductor 21 may be a stranded wire formed by twisting together wires made of a conductive metal material such as copper, a copper alloy, aluminum, or an aluminum alloy. The insulating coating 22 is made of a resin material that is flexible and electrically insulating. At both ends of the electric wire 20, the insulating coating 22 is removed to expose a part of the conductor 21.

[0014] A terminal fitting 30 is crimped to one end of the electric wire 20 where the conductor 21 is exposed. The terminal fitting 30 is formed by processing a plate material made of a conductive metal material such as copper, a copper alloy, aluminum, or an aluminum alloy. As shown in FIG. 1B, the terminal fitting 30 has an electric wire connection portion 31 and an electrical connection portion 32.

[0015] The wire connection portion 31 of the terminal fitting 30 has a conductor crimping portion 311 that is crimped to the conductor 21 of the electric wire 20, and a coating crimping portion 312 that is crimped to the insulator coating portion 22 of the electric wire 20. The conductor crimping portion 311 has a pair of conductor crimping pieces 311a, and the conductor 21 is crimped and fixed to the conductor crimping portion 311 by crimping the conductor crimping pieces 311a. Similarly, the coating crimping portion 312 has a pair of coating crimping pieces 312a, and the insulator coating portion 22 is crimped and fixed to the coating crimping portion 312 by crimping the coating crimping pieces 312a. In this way, the terminal fitting 30 and the electric wire 20 are connected, and electrical continuity is established between the terminal fitting 30 and the conductor 21 of the electric wire 20.

[0016] The electrical connection portion 32 of the terminal fitting 30 has a square cylindrical box portion 33 into which a tab formed on a male terminal to be connected is inserted from the tip side. A connecting portion 34 is provided on the electrical connection portion 32 on the side opposite to the side where the tab is inserted, and the wire connection portion 31 and the electrical connection portion 32 are integrated via the connecting portion 34.

[0017] The box section 33 of the electrical connection section 32 includes a bottom plate section 331, side plate sections 332 and 333 standing on both side edges of the bottom plate section 331, and an upper plate section 334 closing the upper section of the box section 33. A contact 335 protruding inwardly of the box section 33 is formed on the upper plate section 334. A connecting section 34 is integrally formed on the bottom plate section 331 on the electric wire connection section 31 side, and a spring contact 336 is connected to the tip side of the bottom plate section 331. The spring contact 336 is formed by folding back from the tip of the bottom plate section 331 toward the electric wire connection section 31 side inside the box section 33. The spring contact 336 has a pressure contact 337 protruding toward the contact 335 on the upper plate section 334.

[0018] Here, in the electric wire with terminal 10, when ultrasonic joining is performed on the conductor 21 on the other end side of the electric wire 20 to which the terminal fitting 30 is connected at one end, ultrasonic vibration is propagated to the terminal fitting 30 via the electric wire 20. In the terminal fitting 30, the spring contact 336 vibrates in response to the propagated ultrasonic vibration, and a large load is applied to the connected portion with the bottom plate portion 331, which may cause damage. For this reason, in the manufacturing method for an electric wire bundle according to this embodiment, the propagation of ultrasonic vibration to the terminal fitting 30 is suppressed when ultrasonically joining the conductors 21 of a plurality of electric wires with terminals 10 together.

[0019] In the method for manufacturing an electric wire bundle according to the present embodiment, first, a plurality of electric wires with terminals 10 shown in Fig. 1A and Fig. 1B are prepared. As described above, the electric wires with terminals 10 are prepared by removing the insulating coating 22 from both ends of the electric wire 20 to expose a part of the conductor 21. Then, a terminal fitting 30 is crimped to one end of the electric wire 20.

[0020] 2, the conductors 21 exposed at the other ends of the electric wires 20 are placed on the ultrasonic bonding device 40. At this time, the conductors 21 are placed on the ultrasonic bonding device 40 with the ends on the other ends of the electric wires 20 aligned in a direction perpendicular to the longitudinal direction of the electric wires 20.

[0021] The ultrasonic bonding device 40 includes a horn 41 located below the conductor 21 and an anvil 42 located above the conductor 21. The ultrasonic bonding device 40 also includes a fixed side plate and a movable slide core on the side of the conductor 21. The horn 41 is ultrasonically vibrated in the left-right direction in the figure by a vibrator. A knurl consisting of multiple convex stripes protruding in a direction perpendicular to the vibration direction is formed on the upper surface of the horn 41 (the surface that contacts the conductor 21), suppressing slippage between the upper surface of the horn 41 and the conductor 21. Similarly, a knurl consisting of multiple convex stripes protruding in a direction perpendicular to the vibration direction is formed on the lower surface of the anvil 42. In the ultrasonic bonding device 40, the space defined by the horn 41, the side plate, the slide core, and the anvil 42 is a bonding processing space, and the conductors 21 placed in this bonding processing space are ultrasonically bonded to each other.

[0022] Next, with the plurality of electric wires with terminals 10 placed on the ultrasonic joining device 40, the insulator coating portions 22 of the electric wires 20 in the plurality of electric wires with terminals 10 are heated to expand the insulator coating portions 22. Specifically, as shown in Fig. 3, at least a portion of each insulator coating portion 22 is heated using a heating device 50. When the insulator coating portion 22 is heated, the entire heated portion 60 of the insulator coating portion 22 expands toward the outside in the radial direction of the electric wire 20, and therefore the adhesion between the conductor 21 and the insulator coating portion 22 decreases.

[0023] The method for heating the insulating coating parts 22 is not particularly limited, and for example, a heating device 50 that emits hot air can be used. Specifically, in a state where the heating device 50 is disposed near the electric wire with terminal 10, hot air 51 is emitted from the heating device 50 and blown onto the side surface of the insulating coating parts 22. As a result, a part of each insulating coating part 22 is heated to the temperature of the hot air 51, and a heated part 60 is generated. Note that the heat medium to be brought into contact with the insulating coating parts 22 is not limited to a gas, and may be a liquid.

[0024] Then, with the insulator covering portion 22 heated, ultrasonic vibration is applied to the multiple conductors 21 placed inside the ultrasonic bonding device 40, thereby ultrasonically bonding the conductors 21 together. Specifically, as shown in Fig. 4, the multiple conductors 21 are clamped between the horn 41 and the anvil 42 of the ultrasonic bonding device 40, and then a current is passed through the vibrator. This causes the horn 41 to ultrasonically vibrate due to the vibrator, and ultrasonic vibration energy is transmitted to the conductors 21. Then, after oxide films and the like on the surfaces of the conductors 21 are destroyed and removed, the conductors 21 are bonded to each other.

[0025] Finally, the joined conductors 21 are removed from the ultrasonic joining device 40, and the insulator coating portion 22 is cooled to room temperature, thereby obtaining a wire bundle in which the conductors 21 of multiple terminal-equipped electric wires 10 are ultrasonically joined.

[0026] Here, when the insulator sheath 22 is not heated, the conductor 21 and the insulator sheath 22 are in close contact with each other, and the adhesion between the conductor 21 and the insulator sheath 22 is high. When the adhesion between the conductor 21 and the insulator sheath 22 is high, the friction between the conductor 21 and the insulator sheath 22 is also high. Therefore, when ultrasonic vibration is applied to the conductor 21 exposed at the other end of the electric wire 20, the conductor 21 and the insulator sheath 22 vibrate together. That is, the conductor 21 and the insulator sheath 22 vibrate at approximately the same frequency. As a result, the ultrasonic vibration propagates to the terminal fitting 30 via the conductor 21 and the insulator sheath 22, which may damage the terminal fitting 30.

[0027] On the other hand, when the insulator sheath 22 is heated, the entire insulator sheath 22 expands radially outward at the heated portion 60, and the adhesion between the conductor 21 and the insulator sheath 22 decreases. When the adhesion decreases, the force that moves the conductor 21 due to ultrasonic vibration becomes greater than the static friction force between the conductor 21 and the insulator sheath 22, and the conductor 21 and the insulator sheath 22 vibrate separately from each other. That is, the conductor 21 and the insulator sheath 22 vibrate at different frequencies. When the conductor 21 and the insulator sheath 22 vibrate separately from each other, the conductor 21 and the insulator sheath 22 slide against each other, and a frictional force (kinetic frictional force) is generated between the conductor 21 and the insulator sheath 22. As a result, the ultrasonic vibration propagating to the conductor 21 and the insulator sheath 22 is attenuated by the frictional force, and the ultrasonic vibration is less likely to propagate to the terminal fitting 30, and damage to the terminal fitting 30 can be suppressed.

[0028] Therefore, the temperature of the insulator covering part 22 when heated is preferably equal to or higher than the temperature at which the insulator covering part 22 expands and the conductor 21 and the insulator covering part 22 start to move separately. In other words, the temperature of the insulator covering part 22 when heated is preferably equal to or higher than the temperature at which the insulator covering part 22 expands and the conductor 21 and the insulator covering part 22 vibrate at different frequencies.

[0029] In addition, the upper limit of the temperature of the insulating coating portion 22 when the insulating coating portion 22 is heated is not particularly limited, but it can be set to, for example, the upper limit of the temperature determined for handling the electric wire 20, i.e., the heat resistance temperature.

[0030] As described above, in the manufacturing method of the present embodiment, the insulator covering portion 22 can be heated in a state where the plurality of electric wires with terminals 10 are placed on the ultrasonic joining device 40. However, the timing of heating the insulator covering portion 22 is not limited to this embodiment. For example, the insulator covering portions 22 of the plurality of electric wires with terminals 10 may be heated in advance, and then the electric wires with terminals 10 may be placed on the ultrasonic joining device 40.

[0031] 3, the heated portion 60 when the insulator sheathed portion 22 is heated can be at least a part of the insulator sheathed portion 22. The heated portion 60 can be, for example, a portion of the insulator sheathed portion 22 near the middle between the terminal fitting 30 and the conductor 21 exposed at the other end of the electric wire 20. The heated portion 60 can be a portion of the insulator sheathed portion 22 near the terminal fitting 30 or near the conductor 21 exposed at the other end of the electric wire 20.

[0032] 5, the heated portion 60 may be the entire terminal fitting 30 and the insulator sheath 22 of each electric wire with terminal 10. In particular, by using the entire insulator sheath 22 as the heated portion 60, the conductor 21 and the insulator sheath 22 become separate bodies and are more likely to vibrate, so that the conductor 21 and the insulator sheath 22 slide against each other, making it easier to attenuate the ultrasonic vibration.

[0033] The heated portion 60 in the insulating sheath 22 may be one location, as shown in Fig. 3. Alternatively, the heated portion 60 may be multiple locations along the longitudinal direction of the electric wire 20, as shown in Fig. 6. By providing the heated portion 60 at one location, the insulating sheath 22 can be heated easily. By providing the heated portions 60 at multiple locations, the number of locations where the conductor 21 and the insulating sheath 22 slide against each other increases, making it easier to attenuate ultrasonic vibrations.

[0034] As described above, the method for heating the insulator coating portion 22 is not particularly limited, and the heated portion 60 may be generated by blowing hot air onto the insulator coating portion 22. The heated portion 60 may also be generated by blowing heated liquid onto the insulator coating portion 22. Furthermore, the heated portion 60 may also be generated by heating the insulator coating portion 22 using a thermostatic bath.

[0035] In addition, as long as there is no effect on the ultrasonic bonding portion formed by ultrasonically bonding multiple conductors 21 and the terminal crimping portion formed by crimping a terminal fitting 30 to one end of the electric wire 20, the heated portion 60 may be created by immersing the electric wire 20 and the terminal fitting 30 in a heated liquid.

[0036] Furthermore, the thickness (diameter) of the electric wires 20 of the multiple electric wires with terminals 10 may be the same or different from each other. In this embodiment, regardless of the thickness of the electric wires 20, the heated portion 60 can be generated for each electric wire 20, so that the ultrasonic vibration to the terminal fitting 30 can be attenuated.

[0037] As described above, the manufacturing method of the electric wire bundle according to the present embodiment is a manufacturing method of an electric wire bundle in which a plurality of electric wires with terminals 10, each of which is formed by connecting a terminal fitting 30 to one end of an electric wire 20 having a conductor 21 covered with an insulating coating 22, are joined together. The manufacturing method includes a step of heating the insulating coating 22 of the plurality of electric wires with terminals 10 to expand the insulating coating 22. The manufacturing method further includes a step of ultrasonically joining the plurality of conductors 21 together by applying ultrasonic vibration to the plurality of conductors 21 exposed from the plurality of electric wires with terminals 10 in a state in which the insulating coating 22 is expanded.

[0038] In the manufacturing method of this embodiment, ultrasonic vibration is applied to the conductor 21 in a state in which the insulator sheath 22 is expanded, so that the conductor 21 and the insulator sheath 22 slide against each other, generating a frictional force between the conductor 21 and the insulator sheath 22. As a result, the ultrasonic vibration propagating to the conductor 21 and the insulator sheath 22 is attenuated by the frictional force, so that the ultrasonic vibration is less likely to propagate to the terminal fitting 30, and damage to the terminal fitting 30 can be suppressed. Furthermore, in the manufacturing method of this embodiment, there is no need to clamp each electric wire with a pair of jigs (plates) as in Patent Document 1, so that the propagation of ultrasonic vibration to the terminal fitting can be suppressed in a simpler manner.

[0039] In this embodiment, the temperature of the insulator sheath 22 when it is heated may be a temperature at which the conductor and the insulator sheath in each electric wire with terminal 10 vibrate at different frequencies when ultrasonic vibration is applied to the conductor 21 in a state where the insulator sheath is expanded. This causes sliding between the conductor 21 and the insulator sheath 22 to generate frictional force, so that the ultrasonic vibration propagating to the conductor 21 and the insulator sheath 22 can be attenuated.

[0040] In this embodiment, the insulating coating portion 22 may be heated by bringing at least one of heated hot air and liquid into contact with the insulating coating portion 22. Therefore, the heated portion 60 can be generated by a simple device such as a hot air generator.

[0041] In this embodiment, one or more locations of the insulating sheath 22 of each electric wire with terminal 10 may be heated. By providing one heated location 60, it is possible to easily heat the insulating sheath 22. By providing multiple heated locations 60, the number of locations where the conductor 21 and the insulating sheath 22 slide against each other increases, making it easier to attenuate ultrasonic vibrations.

[0042] In the present embodiment, the entire terminal fitting and the insulating coating portion of each electric wire with terminal 10 may be heated. This makes the conductor 21 and the insulating coating portion 22 separate from each other and more likely to vibrate, causing sliding between the conductor 21 and the insulating coating portion 22 and making it easier to attenuate ultrasonic vibration.

[0043] [Method of manufacturing electric wire joint] Next, a method for producing an electric wire joint body according to the present embodiment will be described in detail, with the same description as in the above-mentioned method for producing an electric wire bundle being omitted.

[0044] As described above, the propagation of ultrasonic vibration to the terminal fitting can be suppressed by forming the heated portion 60 in the insulating coating portion 22 of the electric wire with terminal 10. Such a vibration suppression method can be applied not only to the manufacture of electric wire bundles, but also to the manufacture of an electric wire joint body in which an electric wire with terminal and a conductive member are ultrasonically joined together.

[0045] In the manufacturing method of the electric wire joint body according to the present embodiment, first, an electric wire with terminal 10 is prepared. The electric wire with terminal 10 may be one or more. Furthermore, a conductive member 70 to be connected to the electric wire with terminal 10 is also prepared. The conductive member 70 is not particularly limited, but may be, for example, a metal terminal different from the terminal fitting 30 or a bus bar.

[0046] 7, the conductor 21 exposed at the other end of the electric wire 20 and the conductive member 70 are placed on the ultrasonic bonding device 40. At this time, the conductor 21 of the electric wire 20 and the conductive member 70 are placed on the ultrasonic bonding device 40 so as to overlap each other in a direction perpendicular to the longitudinal direction of the electric wire 20.

[0047] Next, with the terminal-fitted electric wire 10 and the conductive member 70 placed on the ultrasonic joining device 40, the insulator coating portion 22 of the electric wire 20 in the terminal-fitted electric wire 10 is heated to create a heated portion 60 and expand the insulator coating portion 22.

[0048] Then, with the insulator covering portion 22 being heated, ultrasonic vibration is applied to the conductor 21 and the conductive member 70 placed on the ultrasonic bonding device 40, thereby ultrasonically bonding the conductor 21 and the conductive member 70 together.

[0049] Finally, the joined conductor 21 and conductive member 70 are removed from the ultrasonic joining device 40, and the insulator coating portion 22 is cooled to room temperature, thereby obtaining an electric wire joint in which the conductor 21 and conductive member 70 of the terminal-equipped electric wire 10 are ultrasonically joined.

[0050] As described above, the manufacturing method of the electric wire joined body according to the present embodiment is a manufacturing method of an electric wire joined body in which an electric wire with terminal 10, which is formed by connecting a terminal fitting 30 to one end of an electric wire 20 having a conductor 21 covered with an insulator coating portion 22, is joined to a conductive member 70. The manufacturing method includes a step of heating the insulator coating portion 22 in the electric wire with terminal 10 to expand the insulator coating portion 22. The manufacturing method further includes a step of applying ultrasonic vibration to the conductor 21 exposed from the electric wire with terminal 10 in a state in which the insulator coating portion 22 is expanded, thereby ultrasonically joining the conductor 21 and the conductive member 70.

[0051] In the manufacturing method of this embodiment, ultrasonic vibration is applied to the conductor 21 in a state in which the insulator sheath 22 is expanded, so that the conductor 21 and the insulator sheath 22 slide against each other, generating a frictional force between the conductor 21 and the insulator sheath 22. As a result, the ultrasonic vibration propagating to the conductor 21 and the insulator sheath 22 is attenuated by the frictional force, making it difficult for the ultrasonic vibration to propagate to the terminal fitting 30, and thus damage to the terminal fitting 30 can be suppressed.

[0052] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0053] 10 Wires with terminals 20 Electric wire 21 Conductor 22 Insulating coating 30 Terminal fitting 70 Conductive materials

Claims

1. A method for manufacturing an electric wire bundle in which a plurality of electric wires with terminals are joined together, the electric wires being each formed by connecting a terminal fitting to one end of an electric wire having a conductor covered with an insulating coating, comprising the steps of: heating the insulating coating portions of the plurality of electric wires with terminals to expand the insulating coating portions; applying ultrasonic vibration to the conductors exposed from the electric wires with terminals while the insulating coating portion is in an expanded state, thereby ultrasonically joining the conductors together; The method for producing an electric wire bundle comprising the steps of:

2. 2. The method for manufacturing an electric wire bundle according to claim 1, wherein a temperature of the insulator sheath when the insulator sheath is heated is a temperature at which the conductor and the insulator sheath in each electric wire with terminal vibrate at frequencies different from each other when ultrasonic vibration is applied to the conductor in a state in which the insulator sheath is expanded.

3. 3. The method for producing an electric wire bundle according to claim 1, wherein the insulating coating portion is heated by contacting at least one of heated hot air and a liquid with the insulating coating portion.

4. The method for producing an electric wire bundle according to claim 1 or 2, further comprising heating one or more locations of the insulating coating portion of each of the electric wires with terminals.

5. The method for producing an electric wire bundle according to claim 1 or 2, wherein the terminal fittings and the insulating coating portion of each of the electric wires with terminals are entirely heated.

6. A method for manufacturing an electric wire joint body in which a terminal-attached electric wire is joined to a conductive member, the terminal-attached electric wire being formed by connecting a terminal fitting to one end of an electric wire having a conductor covered with an insulating coating, comprising the steps of: a step of heating the insulating coating portion of the electric wire with terminal to expand the insulating coating portion; a step of ultrasonically bonding the conductor and the conductive member by applying ultrasonic vibration to the conductor exposed from the electric wire with terminal while the insulating coating portion is in a expanded state; The method for producing an electric wire joint body comprising the steps of:

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