JP7516135B2 - Method and device for joining electric wires - Google Patents

Description

The present invention relates to a method and device for joining electric wires.

For example, in the automotive industry, it has been common to join the conductive wires at the ends of electric wires drawn from multiple electronic devices installed in an automobile, and then attach the joined and aggregated conductor to the body panel of the automobile, etc., for grounding. A commonly used method for joining such electric wires is ultrasonic joining, which disperses impurities on the surface of the conductive wire, such as the oxide film, and firmly joins the metal parts of the conductive wires using ultrasonic vibrations.

For example, in the conventional method of joining electric wires disclosed in Patent Document 1, the surface of the conductive wire at the tip of the electric wire is roughened and then joined by ultrasonic bonding, thereby increasing the strength of the joint.

JP 2016-201313 A

The conventional method of joining electric wires disclosed in Patent Document 1 is effective when the conductive wires to be joined are single wires (especially thin single wires) of approximately the same diameter. However, the conductive wires used in automobiles and the like are often made by twisting multiple strands of wires together, taking into consideration ease of bending, and the like, and the diameters and twisting methods are also various. Furthermore, when joining the conductive wires at the ends of multiple electric wires, in order to improve work efficiency, it is common not to consider the arrangement of the conductive wires at the ends of the electric wires to strengthen the joint strength of the joint. As such, because the joining conditions vary for many reasons, a method and apparatus for joining electric wires that can achieve the required joint strength of the joint of the electric wires and achieve stable joining even under various different joining conditions has not yet been seen or heard, including the conventional technology disclosed in Patent Document 1.

The object of the present invention is to provide a method and device for joining electric wires that can provide the required joining strength at the joint of the electric wires and can achieve stable joining even under various different joining conditions.

The method of joining electric wires of the present invention is a method of joining electric wires for joining the tip portions of a plurality of electric wires, comprising: an insulating coating removal step of removing an insulating coating covering an outer circumference of a conductive wire at the tip portion of the plurality of electric wires; an untwisting step of untwisting strands of the conductive wire at the tip portion of at least one of the plurality of electric wires from which the insulating coating has been removed; and a joining step of joining the conductive wires at the tip portions of the plurality of electric wires by ultrasonic joining in which ultrasonic vibrations are applied while applying a compressive pressure from a radial side portion of the conductive wire to form a joint, and is characterized by including an insulating coating removal/untwisting step in which the insulating coating removal step and the untwisting step are performed simultaneously .

The method of joining electric wires according to the present invention makes it possible to obtain the required joining strength at the joint of the electric wires even under a variety of different joining conditions, and to achieve a stable joint.

FIG. 2 is a flow diagram of a method for joining electric wires according to the first embodiment of the present invention. 1A is a plan view showing an electric wire before the insulating coating is removed, and FIG. 1B is a plan view showing the electric wire after the insulating coating is removed, in an insulating coating removal step of a method for joining electric wires according to a first embodiment. FIG. 2A is a plan view showing the electric wires before untwisting, and FIG. 2B is a plan view showing the electric wires after untwisting, in an untwisting step of a method for joining electric wires according to a first embodiment. 1 is a side view showing a state in which conductive wires at the tip portions of a plurality of electric wires are set in an ultrasonic joining device in a joining step of a method for joining electric wires according to a first embodiment. FIG. FIG. 11 is a side view showing a state in which, after the conductive wires at the tip ends of a plurality of electric wires are set in an ultrasonic joining device, the anvil is closed to perform joining in a joining step of the method for joining electric wires according to the first embodiment. 1 is a side view showing a state in which joining of conductive wires at the tips of a plurality of electric wires has been completed in an ultrasonic joining device in a joining step of a method for joining electric wires according to a first embodiment. FIG. 1 is a plan view showing a state in which joining of conductive wires at the ends of a plurality of electric wires has been completed in the method for joining electric wires according to the first embodiment. FIG. 10 is a side view showing a state in which conductive wires at the tip portions of a plurality of electric wires are set in an ultrasonic joining device in a joining process of a method for joining electric wires in a comparative example. FIG. 10 is a side view showing a state in which, after conductive wires at the tip portions of a plurality of electric wires are set in an ultrasonic joining device, the anvil is closed to perform joining in a joining step of a method for joining electric wires in a comparative example. FIG. 10 is a side view showing a state in which joining of conductive wires at the ends of a plurality of electric wires has been completed in an ultrasonic joining device in a joining process of a method for joining electric wires in a comparative example. FIG. FIG. 6 is a flow diagram of a method for joining electric wires according to a second embodiment of the present invention.

The first embodiment of the present invention will be described below with reference to Figs. 1 to 7. Fig. 1 is a flow diagram of the method for joining electric wires in this embodiment, and Figs. 2 to 7 are explanatory diagrams for explaining the method for joining electric wires in this embodiment.

In the method for joining electric wires according to this embodiment, in the insulating coating removal step S1 in FIG. 1, the insulating coating 2 covering the conductive wire 3 at the tip of a plurality of electric wires 1 (1A, 1B) (two wires as an example here) is cut away and removed as shown in FIGS. 2(a) and 2(b). To remove the insulating coating 2, a jig or device for removing the insulating coating is used, which makes an incision down to the surface of the conductive wire 3 and pulls off the cuttings of the insulating coating 2 to the outside.

Next, in the untwisting process S2 in FIG. 1, as shown in FIG. 3(a) and FIG. 3(b), the strands 4, ... of the conductive wires 3 at the ends of the multiple electric wires 1 (1A, 1B) from which the insulating coating 2 has been removed are untwisted. To untwist the strands 4, ... of the conductive wires 3, for example, an untwisting tool or device is used that grips the surface of the strands 4, ... of the conductive wires 3 and rotates them in the opposite direction to the twisting direction to untwist them.

Next, in the joining step S3 in FIG. 1, as shown in FIG. 4, the conductive wires 3 at the tips of the multiple electric wires 1 (1A, 1B) in which the strands 4, ... have been untwisted are set in an ultrasonic joining device 5 consisting of a horn 51, an anvil 52, and gliding jaws 53, 53. Then, as shown in FIG. 5, the anvil 52 of the ultrasonic joining device 5 is closed, and ultrasonic waves are applied in the axial direction of the multiple electric wires 1 (1A, 1B) while pressure is applied from the radial side of the multiple electric wires 1 (1A, 1B) as shown by the white arrows, causing vibration. As shown in FIG. 5, the strands 4, ... of the conductive wires 3 at the tips of the multiple electric wires 1 (1A, 1B) are displaced and are crimped with a substantially uniform density to form a joined joint 6. Note that, as shown in FIG. 7, the marks of the knurled protrusions on the surface of the horn 51 and the anvil 52 are firmly transferred to the front and back surfaces of the joint 6. In addition, the method of joining electric wires in this embodiment may be performed manually by an operator, or may be performed automatically using an electric wire joining device, an example of which will be described later. In addition, when applying pressure to the radial side of the multiple electric wires 1 (1A, 1B) using the ultrasonic joining device 5, the pressure may be applied from the horn 51 side.

According to the above-described method for joining electric wires of the present embodiment, even under various different joining conditions, the joining strength of the joint portion 6 of the electric wires 1 (1A, 1B) can be made as required, and stable joining can be achieved. For example, as shown in Figs. 4 and 5, even if the conductive wire 3 of the electric wire 1A having a large diameter and the conductive wire 3 of the electric wire 1B having a smaller diameter are considered in the joining conditions, the joining strength of the joint portion 6 of the electric wires 1 (1A, 1B) cannot be made as required and stable joining cannot be achieved, as described in the comparative example below, as in the present embodiment, without the untwisting process S2. In addition, if the arrangement of the multiple electric wires 1 is good, the joining strength of the joint portion 6 can be made as required, and stable joining can be achieved. However, including such a case, considering the large number of electric wires 1, the difference in diameter, and the various ways of twisting the wires 4, ... of the conductive wire 3, the joining conditions are various in any case, and it is not efficient to consider the arrangement of the multiple electric wires 1. In other words, the method of joining electric wires in this embodiment can be carried out efficiently, ignoring such variations in joining conditions.

To explain the effectiveness of the action and effect of the method for joining electric wires of the present embodiment, a comparison is made with the method for joining electric wires of the comparative example shown in Figures 8 to 10. The method for joining electric wires of the comparative example also has an insulating coating removal step S1 and a joining step S3, like the method for joining electric wires of the first embodiment described above. The method for joining electric wires of the comparative example differs from the method for joining electric wires of the first embodiment described above in that it does not have an untwisting step S3. The differences are described in detail below. Note that in the comparative example, configurations that are substantially similar to those of the first embodiment described above are given the same reference numerals and descriptions are omitted or simplified.

In the method of joining electric wires of this comparative example, as shown in Figures 8 to 10, since there is no untwisting step S3, the conductive wires 3 of the electric wires 1A and 1B remain twisted. Therefore, in order to easily distinguish it from the method of joining electric wires of the first embodiment described above, the end faces of the electric wires 1A and 1B are indicated with dots, omitting the wires 4, .... In the joining step S3, as shown in Figure 8, the conductive wires 3 at the tip of the multiple electric wires 1 (1A, 1B) with the wires 4, ... twisted are set in an ultrasonic joining device 5 consisting of a horn 51, an anvil 52, and gliding jaws 53, 53. As shown in Figures 8 and 9, the diameter of the conductive wire 3 of the electric wire 1A on the left side is nearly three times larger than the conductive wire 3 of the electric wire 1B on the right side, and since both conductive wires 3 remain twisted, they all have the rigidity of a single lump. As shown in FIG. 9, the anvil 52 of the ultrasonic bonding device 5 is closed, and ultrasonic waves are applied to the axial direction of the multiple electric wires 1 (1A, 1B) while applying pressure from the radial side of the multiple electric wires 1 (1A, 1B) as shown by the white arrows, and the multiple electric wires 1 (1A, 1B) are vibrated. However, since the tip of the anvil 52 does not contact the surface of the conductive wire 3 of the right electric wire 1B, a bonding force with unevenness is performed. Therefore, as shown in FIG. 10, even when the conductive wire 3 at the tip of the multiple electric wires 1 (1A, 1B) is deformed, crimped, and bonded, a bonding portion 60 with uneven density is formed. In other words, the part 60a where the conductive wire 3 at the tip of the electric wire 1B of the bonding portion 60 is deformed has a lower density than the other parts, and the bonding strength of the bonding portion 60 of the electric wires 1 (1A, 1B) cannot be required, and a stable bonding is not performed.

Next, we will explain an example of an apparatus for joining electric wires that uses the method for joining electric wires according to the first embodiment of the present invention.

Although not shown in the figure, the device for joining electric wires in this example includes an insulation removal device (insulation removal means), an untwisting device (untwisting means), and a joining device (joining means).

The insulation removal device automatically performs the insulation removal process S1, which removes the insulation 2 that covers the outer periphery of the conductive wire 3 at the tip of multiple electric wires 1 (1A, 1B).

The untwisting device automatically performs the untwisting process S2, which untwists the strands 4, ... of the conductive wires 3 at the ends of the multiple electric wires 1 (1A, 1B) from which the insulating coating 2 has been removed by the insulating coating removal device.

The joining device automatically performs a joining process S3 in which the conductive wires 3 at the ends of the multiple electric wires 1 (1A, 1B) that have been untwisted by the untwisting device are joined by ultrasonic joining, which applies ultrasonic vibrations while applying compressive pressure from the radial sides, to form a joint 6.

The insulation coating removal device, untwisting device, and joining device may be connected by a conveying means such as a belt conveyor and controlled by a central processing unit (control unit) to automate the entire system.

The electric wire joining device of this example can automatically perform the electric wire joining method of the first embodiment described above.

Next, a second embodiment of the present invention will be described with reference to FIG. 11. FIG. 11 is a flow diagram of the method for joining electric wires according to this embodiment. The method for joining electric wires according to this embodiment also has a joining step S3, similar to the method for joining electric wires according to the first embodiment described above. The method for joining electric wires according to this embodiment differs from the method for joining electric wires according to the first embodiment in that it has an insulating coating removal and untwisting step S10 in which an insulating coating removal step S1 and an untwisting step S2 are simultaneously performed. The differences will be described in detail below. Note that in this embodiment, configurations that are substantially similar to those of the first embodiment described above are given the same reference numerals, and descriptions thereof will be omitted or simplified.

In the method for joining electric wires of this embodiment, in the insulating coating removal and untwisting step S10, an incision is made to the surface of the conductive wire 3, and the cutting residue of the insulating coating 2 is removed to the outside, while the surface is gripped and rotated in the opposite direction to the twisting direction, or the cutting residue of the insulating coating 2 is removed to the outside with a comb-like shape, while the strands 4, ... are untwisted. Using a jig or device that can simultaneously remove the insulating coating 2 and untwist the strands 4, ... of the conductive wire 3, the insulating coating removal step S1 and the untwisting step S2 are performed simultaneously. Therefore, in the method for joining electric wires of this embodiment, since the insulating coating removal step S1 and the untwisting step S2 are performed simultaneously, a product can be manufactured with even greater time efficiency than the method for joining electric wires of the first embodiment.

Next, an example of an electric wire joining device that applies the electric wire joining method according to the second embodiment of the present invention will be described. Although not shown in the drawings, the electric wire joining device of this example is different from the electric wire joining device that applies the electric wire joining method of the first embodiment in that it is equipped with an insulation removal/untwisting device (insulation removal/untwisting means) that can simultaneously perform insulation removal processing by an insulation removal device and untwisting processing by an untwisting device. The differences will be described in detail below. Note that in this example, configurations that are substantially similar to those of the example in which the first embodiment described above is applied are given the same reference numerals and descriptions thereof will be omitted or simplified.

In the electric wire joining device of this embodiment, instead of an insulation coating removal device that performs an insulation coating removal process S1 to remove the insulation coating 2 covering the outer periphery of the conductive wire 3 at the tip of a plurality of electric wires 1 (1A, 1B) and an untwisting device that performs an untwisting process S2 to untwist the strands 4, ... of the conductive wire 3 at the tip of a plurality of electric wires 1 (1A, 1B) from which the insulation coating 2 has been removed, an insulation coating removal and untwisting device that automatically performs an insulation coating removal and untwisting process S10 that can simultaneously perform the insulation coating removal process by the insulation coating removal device and the untwisting process by the untwisting device is provided. Therefore, compared to the electric wire joining device that applies the electric wire joining method of the first embodiment, products can be manufactured more efficiently in time, in a smaller space, and at a lower cost. In addition, in the case of the device for joining electric wires in this example, the insulation removal/untwisting device and the joining device can be connected by a conveying means such as a belt conveyor and controlled by a central processing unit (control unit) to automate the entire device.

The above describes in detail the form for carrying out the present invention based on the first and second embodiments with reference to the drawings, but the specific configuration is not limited to these embodiments, and design changes that do not deviate from the gist of the present invention are included in the present invention.

For example, in the first and second embodiments described above, the conductive wires 3 of the multiple electric wires 1 (1A, 1B) are all made up of multiple strands 4, ... but this is not limited thereto, and it is also possible to mix in electric wires with a single strand 4.

S1: Insulation sheath removal step S2: Untwisting step S3: Joining step S10: Insulation sheath removal and untwisting step 1, 1A, 1B: Electric wire 2: Insulation sheath 3: Conductive wire 4: Wire 6: Joint

Claims (3)

A method for joining tip portions of a plurality of electric wires, comprising the steps of:
an insulating coating removal process for removing insulating coatings covering outer peripheries of the conductive wires at the tip portions of the plurality of electric wires;
an untwisting step of untwisting the conductive wires at the tip of at least one of the plurality of electric wires from which the insulating coating has been removed;
a joining process for joining the conductive wires at the tip ends of the plurality of electric wires by ultrasonic joining in which ultrasonic vibration is applied while applying a compressive pressure from a radial side portion of the conductive wires to form a joint ,
The method includes an insulating coating removal/untwisting step in which the insulating coating removal step and the untwisting step are performed simultaneously.
A method for joining electric wires, comprising: 2. The method for joining electric wires according to claim 1 , wherein in the untwisting step, the strands of the conductor wires at the tip portions of all of the plurality of electric wires in which the strands of the conductor wires are twisted are untwisted. A wire joining device for joining tip portions of a plurality of wires, comprising:
an insulating coating removing means capable of removing an insulating coating covering an outer periphery of the conductive wires at the tip portions of the plurality of electric wires;
an untwisting means for untwisting a conductive wire at a tip end of at least one of the plurality of electric wires from which the insulating coating has been removed by the insulating coating removing means;
and a joining means capable of performing a process of joining the conductive wires at the tip portions of the plurality of electric wires, including those whose strands have not been untwisted by the untwisting means, by ultrasonic joining in which ultrasonic vibrations are applied while applying a compressive pressure from radial sides of the conductive wires to form a joint ,
The wire is provided with an insulating coating removal/untwisting means capable of simultaneously performing the insulating coating removal process by the insulating coating removal means and the untwisting process by the untwisting means.
A device for joining electric wires, comprising:

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