JP2012134103A - Method for connecting insulation electric wire and method of manufacturing wire harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for connecting insulation electric wires in which a plurality of conductors can be surely connected to one another by welding, and to provide a method of manufacturing a wire harness.SOLUTION: The method for connecting the insulation electric wires includes: a step in which conductors 12 are exposed in a predetermined length by uncovering of insulation coating 14 of each insulation electric wire 11; a step in which a twist part 16 is formed by integrally twisting the plurality of exposed conductors 12; a step of cutting a portion which is a middle portion of the twist part 16 and where all element wires 13 are arranged; and a step of connecting the conductors 12 to one another by welding in the cutting portion of the twist part 16.

Description

  The present invention relates to a method of connecting an insulated wire and a method of manufacturing a wire harness, and more particularly to a method of connecting an insulated wire and a method of manufacturing a wire harness that are suitably used for wiring to a vehicle such as an automobile.

  Conventionally, a plurality of insulated wires are wired in a vehicle such as an automobile. The plurality of insulated wires are usually bundled to form a wire harness. When connecting several insulated wires in such a wire harness (splice connection), peel off the insulation coating of the insulated wires to expose the internal conductor, and keep the conductors in contact with each other. The connection is made by welding or crimping.

  As a method of connecting the conductors of such a plurality of insulated wires, arc welding such as TIG (tungsten inert gas) welding may be used in addition to resistance welding and ultrasonic welding.

  FIG. 7A shows a plurality of insulated wires in a state before arc welding is performed and a wire harness is formed, and a welding torch used for arc welding.

  As shown in the figure, the insulated wire 11 includes a conductor 12 composed of a plurality of strands 13 and an insulating coating 14 covering the outer periphery of the conductor 12. In this case, the insulation coating 14 of each insulated wire 11 is peeled off, and the conductor 12 inside the insulation coating 14 is exposed for a predetermined length.

  The conductors 12 of each insulated wire 11 are arranged in parallel so that the respective tips are aligned (stacked in parallel). A welding torch used for TIG welding is disposed in the vicinity of the tips of the plurality of conductors 12.

  The welding torch includes a tungsten electrode 31 formed in a tapered rod shape, and the tip of each conductor 12 is melted by an arc generated between the tungsten electrode 31 and the tip of each conductor 12. It has become. Then, as shown in FIG. 7 (b), the tip of each conductor 12 melts and becomes liquid, thereby forming a welded portion 18 that is integrated into a substantially spherical shape by the action of the surface tension. As a result, the conductors 12 of each insulated wire 11 are electrically connected (spliced). In addition, the following patent document is mentioned as a prior art document relevant to this invention.

JP 2005-322544 A

  As shown in FIG. 7 (a), before arc welding, the exposed conductors 12 of the plurality of insulated wires 11 are simply arranged in parallel (stacked in parallel) to form the conductors constituting the conductor 12. There is a case where a part of 13 is scattered (extruded). When arc welding is performed in a state in which some of the strands 13 are separated (protruded), the protruding strands 13 are transferred to other strands 13 (conductors) in the welded portion 18 as shown in FIG. 12), a welding failure (connection failure) occurs in that it is not connected.

  Therefore, in order to prevent such welding failure (connection failure) due to the protrusion of the wire 13, before performing arc welding, the plurality of insulated wires 11 are exposed as shown in FIG. The conductors 12 are arranged in parallel (stacked in parallel), and each conductor 12 is twisted to form a twisted portion 16 as shown in FIG. 9 (b), and then, as shown in FIG. 10 (a), Arc welding is performed by arranging a welding torch in the vicinity of the tip of the twisted portion 16.

  However, as shown in FIG. 9B and FIG. 10A, the ends of all the strands 13 constituting each conductor 12 are not arranged at the ends of the twisted portions 16, that is, some In some cases, the tip of the strand 13 does not coincide with the tip of the twisted portion 16 (tip of the other strand 13). When arc welding is performed on the tip of the twisted portion 16 in this state, as shown in FIG. 10 (b), the strand 13 that is not located at the tip of the twisted portion 16 is replaced with another strand 13 ( A welding failure (connection failure) that the conductor 12) is not connected has occurred.

  Then, the subject which this invention solves is providing the connection method of the insulated wire which can perform the connection by welding of a some conductor reliably, and the manufacturing method of a wire harness.

  In order to solve the above problems, a method of connecting an insulated wire according to the present invention includes a step of preparing a plurality of insulated wires each having a conductor composed of a plurality of strands and an insulating coating covering the outer periphery of the conductor; The step of exposing the conductor by a predetermined length by peeling off the insulation coating of the insulated wire, the step of integrally twisting the exposed plurality of conductors to form a twisted portion, and the intermediate portion of the twisted portion. And a step of cutting the portion where all the strands are disposed, and a step of connecting the conductors by welding at the cut portion of the twisted portion.

  In this case, it is preferable that the welding is arc welding.

  Further, in order to solve the above problems, the present invention includes a plurality of insulated wires having a conductor composed of a plurality of strands and an insulating coating covering the outer periphery of the conductor, and is exposed from each of the insulated wires. In the method of manufacturing a wire harness in which conductors are connected, a step of exposing the conductor by a predetermined length by peeling off an insulation coating of each insulated wire, and twisting the exposed plurality of conductors integrally A step of forming a portion, a step of cutting a portion that is an intermediate portion of the twisted portion where all the strands are disposed, and a step of connecting the conductors by welding at the cut portion of the twisted portion; The gist is to provide.

  In this case, it is preferable that the welding is arc welding.

  Moreover, it is preferable to make it the structure provided with the process of compressing the welded part after the said welding and the edge part of each said insulation coating with an insulating tube, and compressing the covered said tube to radial direction.

  According to the method for connecting an insulated wire and the method for manufacturing a wire harness according to the present invention, the step of exposing the conductor for a predetermined length by peeling off the insulation coating of each insulated wire, and the plurality of exposed conductors are twisted integrally. Since it includes a step of forming a twisted portion together and a step of cutting a portion where the strands are all disposed in the middle of the twisted portion, all the cutting portions (tips) of the twisted portion are provided. The tip of the strand is supposed to be placed.

  Therefore, before welding, the state in which the tips of all the strands constituting each conductor are not arranged at the ends of the twisted portions, that is, the state where the tips of some strands do not coincide with the tips of the twisted portions is avoided. ing. As a result, it is possible to prevent the occurrence of poor welding in which a wire not arranged at the tip of the twisted portion is not connected to another wire (conductor) in the welded portion, and the wires constituting each conductor are reliably welded. It is possible to connect. As such welding, arc welding is particularly suitable in addition to resistance welding and ultrasonic welding.

  Further, in the method of manufacturing the wire harness according to the present invention, the method includes a step of covering the welded portion after welding and an end of each insulating coating with an insulating tube, and a step of compressing the covered tube in the radial direction. Then, even when a plurality of insulated wires are pulled in different directions, it is possible to prevent the tensile load at that time from being applied to the welded portion by the tube and to protect the welded portion by the tube. . Thereby, the fall of the connection reliability of a welding part can be suppressed. As such an insulating tube, a heat-shrinkable tube, a resin tube, or the like is applied. Further, for example, tubes in which a thermoplastic adhesive layer is formed inside these tubes can be applied.

It is the appearance perspective view showing the state where the conductor was exposed from the end of the plurality of insulated wires concerning the embodiment of the present invention. (A) is the external appearance perspective view which showed the twist part by which the some conductor of FIG. 1 was integrally twisted together, (b) is the external appearance perspective view which showed the state which cut | disconnected the intermediate part of the twist part of (a) It is. FIG. 2A is an external perspective view showing a state where arc welding is performed on the cut portion (tip) of the twisted portion in FIG. 2B, and FIG. 2B shows a welded portion formed at the tip of the twisted portion in FIG. It is the external appearance perspective view which showed the state (namely, wire harness which concerns on embodiment of this invention). It is sectional drawing which showed the state (namely, wire harness which concerns on embodiment of this invention) which covered the heat contraction tube on the welding part of FIG.3 (b), and contracted the heat contraction tube. (A) is sectional drawing which showed the state which covered the resin tube on the welding part of FIG.3 (b), (b) is the state which compressed the resin tube of (a) in the radial direction with the pressurization apparatus (namely, It is sectional drawing which showed the wire harness which concerns on embodiment of this invention. (A) is sectional drawing which showed the state which covered the resin tube on the welding part of FIG.3 (b), (b) is the state which compressed the resin tube of (a) in the radial direction with the pressurization apparatus (namely, It is sectional drawing which showed the wire harness which concerns on embodiment of this invention. (A) is the external appearance perspective view which showed the state which arc-welds to the front-end | tip of the conductor of the several insulated wire which concerns on a prior art, (b) shows the state by which the welding part was formed in the front-end | tip of the conductor of (a). It is the external appearance perspective view shown. It is the external appearance perspective view which showed the state by which some strands are not connected to the welding part of FIG.7 (b). (A) is the external appearance perspective view which showed the state before a several conductor is twisted together, (b) is the external appearance perspective view which showed the twist part by which the several conductor of (a) was twisted together. . (A) is the external appearance perspective view which showed the state which arc-welds to the front-end | tip of the twist part of FIG.9 (b), (b) showed the state by which the welding part was formed in the front-end | tip of the twist part of (a). It is an external perspective view.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the side where the conductor of the insulated wire is exposed will be referred to as the front side (front end side), and the opposite side will be referred to as the rear side (rear end side). 1 to 3, the lower left in the figure is the front side (front end side) and the upper right in the figure is the rear side (rear end side), and in FIGS. 4 to 6, the left in the figure is the front side (front end side) and in the figure The right is the rear side (rear end side).

  As shown in FIG. 1, the insulated wire 11 includes a conductor 12 and an insulating coating 14 that covers the outer periphery of the conductor 12. The conductor 12 includes one or more strands 13 serving as an electrical conductor. As a metal which forms the strand 13, the metal which is excellent in electroconductivity, such as copper, a copper alloy, aluminum, and an aluminum alloy, is preferable. The conductor 12 may be composed of only the strand 13 or may include a reinforcing wire made of stainless steel in order to increase mechanical strength against bending of the conductor 12 (insulated wire 11).

  In this case, as shown in the drawing, a plurality of (three in this embodiment) insulated wires 11 are prepared, and the insulation coating 14 of each insulated wire 11 is peeled off, and the conductors 12 inside the insulation coating 14 are peeled off. Is exposed for a predetermined length.

  As shown in FIG. 1, the conductors 12 of each insulated wire 11 are arranged in parallel so that their tips are aligned (stacked in parallel), and then, as shown in FIG. A plurality of conductors 12 are twisted together to form a twisted portion 16.

  At this time, as shown in FIG. 2 (a), the ends of all the strands 13 constituting each conductor 12 are not arranged at the ends of the twisted portions 16, that is, the ends of some of the strands 13. Is not in agreement with the tip of the twisted portion 16. When arc welding is performed in this state, the strand 13 that is not located at the tip of the twisted portion 16 is not connected to another strand 13 (conductor 12), as shown in FIG. This results in poor welding (connection failure).

  Therefore, using the cutters 21 and 22 as shown in FIG. 2A, a portion that is an intermediate portion of the twisted portion 16 and where the strands 13 are all disposed is cut. The cutters 21 and 22 are provided with V-shaped blade portions 21a and 22a that are vertically opposed to each other. Each blade part 21a, 22a is comprised from the plane parts 21b and 22b along the surface of the cutters 21 and 22, and the inclined slope parts 21c and 22c, and when the twist part 16 is cut | disconnected, mutual plane parts 21b and 22b are comprised. Is slidable.

  In this case, as shown in the drawing, the region A where the wire 13 whose tip does not match the tip of the twisted portion 16 is avoided, and the wire 13 whose tip does not match the tip of the twisted portion 16 In the region B that does not exist, the twisted portion 16 is cut by the cutters 21 and 22. FIG.2 (b) has shown the twist part 16 after a cutting | disconnection. As shown in the drawing, the tips of all the strands 13 are gathered at the cut portion (tip) 16a of the twisted portion 16 after cutting.

  Thereafter, as shown in FIG. 3A, arc welding is performed by placing a welding torch in the vicinity of the cutting portion (tip) 16 a of the twisted portion 16 after cutting.

  The welding torch includes a tungsten electrode 31 formed in a tapered rod shape. The tungsten electrode 31 is electrically connected to a welding power source via a power cable (not shown). The welding power source is electrically connected to the conductor 12 (twisted portion 16) via a ground cable (not shown). Around the tungsten electrode 31, there is provided a substantially cylindrical gas nozzle 32 opened at the tip side of the tungsten electrode 31. The base end side of the gas nozzle 32 is connected to a gas cylinder or the like filled with an inert gas so that the inert gas can be injected from the tip thereof.

  When the welding power source is turned on while injecting an inert gas from the gas nozzle 32, an arc is generated between the tungsten electrode 31 and the tip of the twisted portion 16. Due to the generation of the arc, the tip of the twisted portion 16 is melted.

  As shown in FIG. 3B, the tip of the twisted portion 16 melts and becomes liquid, whereby a welded portion 18 that is integrated into a substantially spherical shape is formed by the action of the surface tension. Thereby, the conductors 12 of each insulated wire 11 are electrically connected (spliced), and the wire harness 10 is obtained.

  Such a welded portion 18 is covered with a heat shrinkable tube 30 having heat shrinkability as shown in FIG. 4 as an insulating tube for protecting the welded portion 18 and the like. FIG. 4 shows the heat-shrinkable tube 30 that is heated and contracted by a heating means such as a dryer (not shown). In this case, the heat shrinkable tube 30 has a length that covers from the front of the welded portion 18 to the end of the insulating coating 14.

  Thus, even if the insulated wire 11 which comprises the wire harness 10 is pulled in a different direction by covering the edge part of the welding part 18 and the insulation coating 14 with the heat contraction tube 30, the tensile load in that case Is prevented from being applied to the welded portion 18 by the heat shrinkable tube 30. Thereby, the fall of the connection reliability of the welding part 18 can be suppressed. In addition, by providing a thermoplastic adhesive layer inside the heat shrinkable tube 30, it is possible to enhance the adhesion to the welded portion 18 and the end of the insulating coating 14.

  As such an insulating tube for protecting the welded portion 18 and the like, a resin tube 40 as shown in FIG. 5A is also applicable. The resin tube 40 has a length that covers from the front of the welded portion 18 to the end of the insulating coating 14. In this case, the resin tube 40 is compressed in the radial direction by a pressurizing device 50 as illustrated.

  The pressure device 50 includes an upper mold 51 and a lower mold 52. The upper mold 51 and the lower mold 52 are arranged so as to face each other vertically. On the lower surface of the upper mold 51, there are formed a concave portion 51 a whose upper portion is recessed upward so as to avoid the opposed welded portion 18, and convex portions 51 b and 51 c that protrude downward before and after the concave portion 51 a. Further, on the upper surface of the lower mold 52, a concave portion 52a having a substantially central portion recessed downward so as to avoid the opposing welded portion 18, and convex portions 52b and 52c projecting upward in front of and behind the concave portion 52a are formed. Yes. The upper mold 51 and the lower mold 52 are movable up and down by pressurizing means (not shown).

  Then, as shown in FIG. 5 (b), the resinous tube 40 is compressed in the radial direction by the pressurization of the upper mold 51 and the lower mold 52 of the pressurizing device 50.

  At this time, the portions disposed before and after the welded portion 18 of the resinous tube 40 are compressed by the convex portions 51b and 51c and the convex portions 52b and 52c facing the portion, but the welded portion 18 of the resinous tube 40 is compressed. The portion disposed in the portion is not compressed as much as the front portion and the rear portion of the resinous tube 40 because there are the concave portion 51a and the concave portion 52a facing the portion. Thereby, the tearing and tearing of the part arrange | positioned at the welding part 18 of the resin tube 40 at the time of pressurization are prevented.

  Thus, even if the insulated wire 11 which comprises the wire harness 10 is pulled in a different direction by covering the edge part of the welding part 18 and the insulation coating 14 with the resin tube 40, the tensile load in that case Is prevented from being applied to the welded portion 18 by the resin tube 40. Thereby, the fall of the connection reliability of the welding part 18 can be suppressed.

  A heating means (not shown) for heating the upper mold 51 may be provided inside the upper mold 51, and a heating means (not shown) for heating the lower mold 52 may also be provided inside the lower mold 52. With such a configuration, the resin tube 40 can be compressed in the radial direction while applying heat, so that the adhesion to the welded portion 18 and the end of the insulating coating 14 can be enhanced. In this case, by providing a thermoplastic adhesive layer on the inner side of the resinous tube 40, the adhesion to the welded portion 18 and the end of the insulating coating 14 can be further enhanced.

  FIG. 6A shows a pressurizing device 60 having a configuration different from the pressurizing device 50 described above. The pressure device 60 includes an upper mold 61 made of a soft material such as rubber, and a lower mold 62 made of a soft material such as rubber. In this case, the lower surface 61a of the upper mold 61 is formed flat. The upper surface 62a of the lower mold 62 is also formed flat. The upper mold 61 and the lower mold 62 can be moved up and down by pressurizing means (not shown).

  Then, as shown in FIG. 6B, the resin tube 40 is compressed in the radial direction by the pressurization of the upper mold 61 and the lower mold 62 of the pressurizing device 60.

  At this time, the portions disposed on the front and back of the welded portion 18 of the resin tube 40 are slightly distorted in the front portion 61b and the rear portion 61c of the upper surface 61a and the front portion 62b and the rear portion 62c of the lower surface 62a. Compressed by the front part 61b and the rear part 61c, and the front part 62b and the rear part 62c (while being recessed).

  Further, the portion of the resinous tube 40 arranged in the welded portion 18 is such that the central portion 61d of the upper surface 61a and the central portion 62d of the lower surface 62a facing this portion are the front portion 61b, the rear portion 61c and the lower surface 62a of the upper surface 61a. While being distorted (depressed) than the front part 62b and the rear part 62c, the central part 61d and the central part 62d are compressed. Thereby, the tearing and tearing of the part arrange | positioned at the welding part 18 of the resin tube 40 at the time of pressurization are prevented.

  According to the above-described method for connecting an insulated wire and a method for manufacturing a wire harness according to the present invention, the step of exposing the conductor 12 by a predetermined length by peeling the insulating coating 14 of each insulated wire 11 and the plurality of exposed conductors 12 is integrally twisted to form a twisted portion 16 and a step of cutting a portion of the twisted portion 16 where the strands 13 are all disposed is provided. At the cutting site (tip) 16a, the tips of all the strands 13 are arranged.

  Therefore, before welding, the ends of all the strands 13 constituting each conductor 12 are not arranged at the ends of the stranded portions 16, that is, the ends of some of the strands 13 coincide with the ends of the stranded portions 16. The state of not doing is avoided. As a result, it is possible to prevent the occurrence of poor welding in which the wire 13 that is not arranged at the tip of the twisted portion 16 is not connected to the other wire 13 (conductor 12) in the welded portion 18, and the wires that constitute each conductor 12 are prevented. It is possible to reliably connect 13 to each other by welding.

  Moreover, in the manufacturing method of the wire harness which concerns on this invention, the process of covering the welded part 18 after welding and the edge part of each insulation coating 14 with the insulating tube 30 (40), and the covered tube 30 (40) If a plurality of insulated wires 11 are pulled in different directions, the tensile load at that time is not applied to the welded portion 18 by the tube 30 (40). And the weld 18 can be protected by the tube 30 (40). Thereby, the fall of the connection reliability of the welding part 18 can be suppressed.

  As mentioned above, although the embodiment of the connection method of the insulated wire and the manufacturing method of the wire harness according to the present invention has been described, the present invention is not limited to such an embodiment and does not depart from the gist of the present invention. Various modifications are possible. For example, in the above-described embodiment, the configuration using three insulated wires 11 has been described. However, the present invention can be applied even if there are four or more wires, and the number of insulated wires 11 is not limited to the above-described embodiment. .

DESCRIPTION OF SYMBOLS 10 Wire harness 11 Insulated electric wire 12 Conductor 13 Strand 14 Insulation coating 16 Twisted part 16a Cutting part (cut surface)
18 Welded parts 21, 22 Cutter 30 Heat shrinkable tube 40 Resin tube 50 Pressurizing device 51 Upper mold 51a Recessed part 51b, 51c Convex part 52 Lower mold 52a Concave part 52b, 52c Convex part 60 Pressurizing apparatus 61 Upper mold 61a Lower surface 61b Front Part 61c rear part 61d center part 62 lower mold 62a lower surface 62b front part 62c rear part 62d center part

Claims (5)

  Preparing a plurality of insulated wires having a conductor composed of a plurality of strands and an insulation coating covering the outer periphery of the conductor, and exposing the conductor to a predetermined length by peeling the insulation coating of each insulated wire A step of integrally twisting the exposed plurality of conductors to form a twisted portion; a step of cutting a portion of the twisted portion where all the strands are disposed; And a step of connecting the conductors by welding at the cut portion of the twisted portion.   The method for connecting insulated wires according to claim 1, wherein the welding is arc welding.   In a method of manufacturing a wire harness in which a plurality of insulated wires having a conductor composed of a plurality of strands and an insulating coating covering the outer periphery of the conductor are provided, and the conductors exposed from the insulated wires are connected to each other A step of exposing the conductor by a predetermined length by peeling off the insulation coating of each insulated wire, a step of integrally twisting the exposed conductors to form a twisted portion, and a middle of the twisted portion A method of manufacturing a wire harness, comprising: a step of cutting a portion where all of the strands are disposed, and a step of connecting the conductors by welding at a cut portion of the twisted portion. .   The method of manufacturing a wire harness according to claim 3, wherein the welding is arc welding.   5. The method according to claim 3, further comprising a step of covering the welded portion after the welding and an end portion of each insulating coating with an insulating tube, and a step of compressing the covered tube in a radial direction. The manufacturing method of the wire harness of description.

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